[PATCH 0/2] OMAP: PM: implement devices wakeup latency constraints APIs

[PATCH 0/2] OMAP: PM: implement devices wakeup latency constraints APIs

[Jean Pihet]

Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
creating similar APIs at the omap_device and omap_hwmod levels. The
omap_hwmod level call is the layer with access to the powerdomain
core, so it is the place where the powerdomain is queried to set and
release the constraints.

NOTE: only works for devices which have been converted to use
      omap_device/omap_hwmod.

Longer term, we could possibly remove this API from the OMAP PM layer,
and instead directly use the device level API.

The power domains get the next power state programmed directly in
the registers via pwrdm_wakeuplat_update_pwrst.

Note about PM QOS: the MPU and CORE power domains get the next power
state via cpuidle, which get the strongest wake-up latency constraint
by querying PM QOS. The usage of PM QOS is temporary, until a generic
solution is in place.

Jean Pihet (2):
  OMAP PM: create a PM layer plugin for the devices wakeup latency
    constraints
  OMAP: PM: implement devices wakeup latency constraints APIs

 arch/arm/mach-omap2/omap_hwmod.c              |   62 +++++-
 arch/arm/mach-omap2/powerdomain.c             |  197 ++++++++++++++
 arch/arm/mach-omap2/powerdomain.h             |   39 +++-
 arch/arm/mach-omap2/powerdomains3xxx_data.c   |   60 ++++
 arch/arm/plat-omap/Kconfig                    |    7 +
 arch/arm/plat-omap/Makefile                   |    1 +
 arch/arm/plat-omap/include/plat/omap_device.h |    2 +
 arch/arm/plat-omap/include/plat/omap_hwmod.h  |    2 +
 arch/arm/plat-omap/omap-pm-constraints.c      |  358 +++++++++++++++++++++++++
 arch/arm/plat-omap/omap_device.c              |   28 ++
 10 files changed, 754 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/plat-omap/omap-pm-constraints.c

-- 
1.7.2.3

[PATCH 1/2] OMAP PM: create a PM layer plugin for the devices wakeup latency constraints

[Jean Pihet]

Created arch/arm/plat-omap/omap-pm-constraints.c file from
arch/arm/plat-omap/omap-pm-noop.c and the associated Kconfig option
OMAP_PM_CONSTRAINTS.

Based on the original patch from Vishwanath,
cf. https://patchwork.kernel.org/patch/327312/

Cc: Vishwanath BS <vishwanath.bs@ti.com>

Signed-off-by: Jean Pihet <j-pihet@ti.com>
---
Based on khilman's pm-core branch

 arch/arm/plat-omap/Kconfig               |    7 +
 arch/arm/plat-omap/Makefile              |    1 +
 arch/arm/plat-omap/omap-pm-constraints.c |  363 ++++++++++++++++++++++++++++++
 3 files changed, 371 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/plat-omap/omap-pm-constraints.c

diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
index b6333ae..b8f51e3 100644
--- a/arch/arm/plat-omap/Kconfig
+++ b/arch/arm/plat-omap/Kconfig
@@ -215,6 +215,13 @@ config OMAP_PM_NONE
 config OMAP_PM_NOOP
 	bool "No-op/debug PM layer"
 
+config OMAP_PM_CONSTRAINTS
+	depends on PM
+	bool "OMAP PM layer implementation, devices wakeup latency constraints"
+	help
+	  Select this option to enable the PM layer plugin for
+	  the devices wakeup latency constraints support
+
 endchoice
 
 endmenu
diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile
index a4a1285..a293367 100644
--- a/arch/arm/plat-omap/Makefile
+++ b/arch/arm/plat-omap/Makefile
@@ -32,3 +32,4 @@ obj-y += $(i2c-omap-m) $(i2c-omap-y)
 obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o
 
 obj-$(CONFIG_OMAP_PM_NOOP) += omap-pm-noop.o
+obj-$(CONFIG_OMAP_PM_CONSTRAINTS) += omap-pm-constraints.o
diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
new file mode 100644
index 0000000..c8b4e4c
--- /dev/null
+++ b/arch/arm/plat-omap/omap-pm-constraints.c
@@ -0,0 +1,363 @@
+/*
+ * omap-pm.c - OMAP power management interface
+ *
+ * This code implements the OMAP power management interface to
+ * drivers, CPUIdle, CPUFreq, and DSP Bridge.
+ *
+ * Copyright (C) 2008-2009 Texas Instruments, Inc.
+ * Copyright (C) 2008-2009 Nokia Corporation
+ * Paul Walmsley
+ *
+ * Interface developed by (in alphabetical order):
+ * Karthik Dasu, Tony Lindgren, Jean Pihet, Rajendra Nayak, Sakari Poussa,
+ * Veeramanikandan Raju, Anand Sawant, Igor Stoppa, Paul Walmsley,
+ * Richard Woodruff
+ */
+
+#undef DEBUG
+
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+
+/* Interface documentation is in mach/omap-pm.h */
+#include <plat/omap-pm.h>
+#include <plat/omap_device.h>
+
+static bool off_mode_enabled;
+static u32 dummy_context_loss_counter;
+
+/*
+ * Device-driver-originated constraints (via board-*.c files)
+ */
+
+int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
+{
+	if (!dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (t == -1)
+		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+
+	/*
+	 * For current Linux, this needs to map the MPU to a
+	 * powerdomain, then go through the list of current max lat
+	 * constraints on the MPU and find the smallest.  If
+	 * the latency constraint has changed, the code should
+	 * recompute the state to enter for the next powerdomain
+	 * state.
+	 *
+	 * TI CDP code can call constraint_set here.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
+{
+	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
+	    agent_id != OCP_TARGET_AGENT)) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (r == 0)
+		pr_debug("OMAP PM: remove min bus tput constraint: "
+			 "dev %s for agent_id %d\n", dev_name(dev), agent_id);
+	else
+		pr_debug("OMAP PM: add min bus tput constraint: "
+			 "dev %s for agent_id %d: rate %ld KiB\n",
+			 dev_name(dev), agent_id, r);
+
+	/*
+	 * This code should model the interconnect and compute the
+	 * required clock frequency, convert that to a VDD2 OPP ID, then
+	 * set the VDD2 OPP appropriately.
+	 *
+	 * TI CDP code can call constraint_set here on the VDD2 OPP.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
+				   long t)
+{
+	if (!req_dev || !dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (t == -1)
+		pr_debug("OMAP PM: remove max device latency constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add max device latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+
+	/*
+	 * For current Linux, this needs to map the device to a
+	 * powerdomain, then go through the list of current max lat
+	 * constraints on that powerdomain and find the smallest.  If
+	 * the latency constraint has changed, the code should
+	 * recompute the state to enter for the next powerdomain
+	 * state.  Conceivably, this code should also determine
+	 * whether to actually disable the device clocks or not,
+	 * depending on how long it takes to re-enable the clocks.
+	 *
+	 * TI CDP code can call constraint_set here.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_max_sdma_lat(struct device *dev, long t)
+{
+	if (!dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (t == -1)
+		pr_debug("OMAP PM: remove max DMA latency constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add max DMA latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+
+	/*
+	 * For current Linux PM QOS params, this code should scan the
+	 * list of maximum CPU and DMA latencies and select the
+	 * smallest, then set cpu_dma_latency pm_qos_param
+	 * accordingly.
+	 *
+	 * For future Linux PM QOS params, with separate CPU and DMA
+	 * latency params, this code should just set the dma_latency param.
+	 *
+	 * TI CDP code can call constraint_set here.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
+{
+	if (!dev || !c || r < 0) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	}
+
+	if (r == 0)
+		pr_debug("OMAP PM: remove min clk rate constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add min clk rate constraint: "
+			 "dev %s, rate = %ld Hz\n", dev_name(dev), r);
+
+	/*
+	 * Code in a real implementation should keep track of these
+	 * constraints on the clock, and determine the highest minimum
+	 * clock rate.  It should iterate over each OPP and determine
+	 * whether the OPP will result in a clock rate that would
+	 * satisfy this constraint (and any other PM constraint in effect
+	 * at that time).  Once it finds the lowest-voltage OPP that
+	 * meets those conditions, it should switch to it, or return
+	 * an error if the code is not capable of doing so.
+	 */
+
+	return 0;
+}
+
+/*
+ * DSP Bridge-specific constraints
+ */
+
+const struct omap_opp *omap_pm_dsp_get_opp_table(void)
+{
+	pr_debug("OMAP PM: DSP request for OPP table\n");
+
+	/*
+	 * Return DSP frequency table here:  The final item in the
+	 * array should have .rate = .opp_id = 0.
+	 */
+
+	return NULL;
+}
+
+void omap_pm_dsp_set_min_opp(u8 opp_id)
+{
+	if (opp_id == 0) {
+		WARN_ON(1);
+		return;
+	}
+
+	pr_debug("OMAP PM: DSP requests minimum VDD1 OPP to be %d\n", opp_id);
+
+	/*
+	 *
+	 * For l-o dev tree, our VDD1 clk is keyed on OPP ID, so we
+	 * can just test to see which is higher, the CPU's desired OPP
+	 * ID or the DSP's desired OPP ID, and use whichever is
+	 * highest.
+	 *
+	 * In CDP12.14+, the VDD1 OPP custom clock that controls the DSP
+	 * rate is keyed on MPU speed, not the OPP ID.  So we need to
+	 * map the OPP ID to the MPU speed for use with clk_set_rate()
+	 * if it is higher than the current OPP clock rate.
+	 *
+	 */
+}
+
+
+u8 omap_pm_dsp_get_opp(void)
+{
+	pr_debug("OMAP PM: DSP requests current DSP OPP ID\n");
+
+	/*
+	 * For l-o dev tree, call clk_get_rate() on VDD1 OPP clock
+	 *
+	 * CDP12.14+:
+	 * Call clk_get_rate() on the OPP custom clock, map that to an
+	 * OPP ID using the tables defined in board-*.c/chip-*.c files.
+	 */
+
+	return 0;
+}
+
+/*
+ * CPUFreq-originated constraint
+ *
+ * In the future, this should be handled by custom OPP clocktype
+ * functions.
+ */
+
+struct cpufreq_frequency_table **omap_pm_cpu_get_freq_table(void)
+{
+	pr_debug("OMAP PM: CPUFreq request for frequency table\n");
+
+	/*
+	 * Return CPUFreq frequency table here: loop over
+	 * all VDD1 clkrates, pull out the mpu_ck frequencies, build
+	 * table
+	 */
+
+	return NULL;
+}
+
+void omap_pm_cpu_set_freq(unsigned long f)
+{
+	if (f == 0) {
+		WARN_ON(1);
+		return;
+	}
+
+	pr_debug("OMAP PM: CPUFreq requests CPU frequency to be set to %lu\n",
+		 f);
+
+	/*
+	 * For l-o dev tree, determine whether MPU freq or DSP OPP id
+	 * freq is higher.  Find the OPP ID corresponding to the
+	 * higher frequency.  Call clk_round_rate() and clk_set_rate()
+	 * on the OPP custom clock.
+	 *
+	 * CDP should just be able to set the VDD1 OPP clock rate here.
+	 */
+}
+
+unsigned long omap_pm_cpu_get_freq(void)
+{
+	pr_debug("OMAP PM: CPUFreq requests current CPU frequency\n");
+
+	/*
+	 * Call clk_get_rate() on the mpu_ck.
+	 */
+
+	return 0;
+}
+
+/**
+ * omap_pm_enable_off_mode - notify OMAP PM that off-mode is enabled
+ *
+ * Intended for use only by OMAP PM core code to notify this layer
+ * that off mode has been enabled.
+ */
+void omap_pm_enable_off_mode(void)
+{
+	off_mode_enabled = true;
+}
+
+/**
+ * omap_pm_disable_off_mode - notify OMAP PM that off-mode is disabled
+ *
+ * Intended for use only by OMAP PM core code to notify this layer
+ * that off mode has been disabled.
+ */
+void omap_pm_disable_off_mode(void)
+{
+	off_mode_enabled = false;
+}
+
+/*
+ * Device context loss tracking
+ */
+
+#ifdef CONFIG_ARCH_OMAP2PLUS
+
+u32 omap_pm_get_dev_context_loss_count(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	u32 count;
+
+	if (WARN_ON(!dev))
+		return 0;
+
+	if (dev->parent == &omap_device_parent) {
+		count = omap_device_get_context_loss_count(pdev);
+	} else {
+		WARN_ONCE(off_mode_enabled, "omap_pm: using dummy context "
+			  "loss counter; device %s should be converted to "
+			  "omap_device", dev_name(dev));
+		if (off_mode_enabled)
+			dummy_context_loss_counter++;
+		count = dummy_context_loss_counter;
+	}
+
+	pr_debug("OMAP PM: context loss count for dev %s = %d\n",
+		 dev_name(dev), count);
+
+	return count;
+}
+
+#else
+
+u32 omap_pm_get_dev_context_loss_count(struct device *dev)
+{
+	return dummy_context_loss_counter;
+}
+
+#endif
+
+/* Should be called before clk framework init */
+int __init omap_pm_if_early_init(void)
+{
+	return 0;
+}
+
+/* Must be called after clock framework is initialized */
+int __init omap_pm_if_init(void)
+{
+	return 0;
+}
+
+void omap_pm_if_exit(void)
+{
+	/* Deallocate CPUFreq frequency table here */
+}
+
-- 
1.7.2.3

Re: [PATCH 1/2] OMAP PM: create a PM layer plugin for the devices wakeup latency constraints

[Kevin Hilman]

Jean Pihet <jean.pihet@newoldbits.com> writes:

> Created arch/arm/plat-omap/omap-pm-constraints.c file from
> arch/arm/plat-omap/omap-pm-noop.c and the associated Kconfig option
> OMAP_PM_CONSTRAINTS.
>
> Based on the original patch from Vishwanath,
> cf. https://patchwork.kernel.org/patch/327312/
>
> Cc: Vishwanath BS <vishwanath.bs@ti.com>
>
> Signed-off-by: Jean Pihet <j-pihet@ti.com>
> ---
> Based on khilman's pm-core branch
>
>  arch/arm/plat-omap/Kconfig               |    7 +
>  arch/arm/plat-omap/Makefile              |    1 +
>  arch/arm/plat-omap/omap-pm-constraints.c |  363 ++++++++++++++++++++++++++++++
>  3 files changed, 371 insertions(+), 0 deletions(-)
>  create mode 100644 arch/arm/plat-omap/omap-pm-constraints.c
>
> diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
> index b6333ae..b8f51e3 100644
> --- a/arch/arm/plat-omap/Kconfig
> +++ b/arch/arm/plat-omap/Kconfig
> @@ -215,6 +215,13 @@ config OMAP_PM_NONE
>  config OMAP_PM_NOOP
>  	bool "No-op/debug PM layer"
>  
> +config OMAP_PM_CONSTRAINTS
> +	depends on PM
> +	bool "OMAP PM layer implementation, devices wakeup latency constraints"

Minor: The 'OMAP PM layer implmentatin' is redundant here as it's a sub-choice
of the OMAP PM layer menu.  How abou just "per-device constraint

Kevin

> +	help
> +	  Select this option to enable the PM layer plugin for
> +	  the devices wakeup latency constraints support
> +
>  endchoice
>  
>  endmenu
> diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile
> index a4a1285..a293367 100644
> --- a/arch/arm/plat-omap/Makefile
> +++ b/arch/arm/plat-omap/Makefile
> @@ -32,3 +32,4 @@ obj-y += $(i2c-omap-m) $(i2c-omap-y)
>  obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o
>  
>  obj-$(CONFIG_OMAP_PM_NOOP) += omap-pm-noop.o
> +obj-$(CONFIG_OMAP_PM_CONSTRAINTS) += omap-pm-constraints.o
> diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
> new file mode 100644
> index 0000000..c8b4e4c
> --- /dev/null
> +++ b/arch/arm/plat-omap/omap-pm-constraints.c
> @@ -0,0 +1,363 @@
> +/*
> + * omap-pm.c - OMAP power management interface
> + *
> + * This code implements the OMAP power management interface to
> + * drivers, CPUIdle, CPUFreq, and DSP Bridge.
> + *
> + * Copyright (C) 2008-2009 Texas Instruments, Inc.
> + * Copyright (C) 2008-2009 Nokia Corporation
> + * Paul Walmsley
> + *
> + * Interface developed by (in alphabetical order):
> + * Karthik Dasu, Tony Lindgren, Jean Pihet, Rajendra Nayak, Sakari Poussa,
> + * Veeramanikandan Raju, Anand Sawant, Igor Stoppa, Paul Walmsley,
> + * Richard Woodruff
> + */
> +
> +#undef DEBUG
> +
> +#include <linux/init.h>
> +#include <linux/cpufreq.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +
> +/* Interface documentation is in mach/omap-pm.h */
> +#include <plat/omap-pm.h>
> +#include <plat/omap_device.h>
> +
> +static bool off_mode_enabled;
> +static u32 dummy_context_loss_counter;
> +
> +/*
> + * Device-driver-originated constraints (via board-*.c files)
> + */
> +
> +int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
> +{
> +	if (!dev || t < -1) {
> +		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> +		return -EINVAL;
> +	};
> +
> +	if (t == -1)
> +		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
> +			 "dev %s\n", dev_name(dev));
> +	else
> +		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
> +			 "dev %s, t = %ld usec\n", dev_name(dev), t);
> +
> +	/*
> +	 * For current Linux, this needs to map the MPU to a
> +	 * powerdomain, then go through the list of current max lat
> +	 * constraints on the MPU and find the smallest.  If
> +	 * the latency constraint has changed, the code should
> +	 * recompute the state to enter for the next powerdomain
> +	 * state.
> +	 *
> +	 * TI CDP code can call constraint_set here.
> +	 */
> +
> +	return 0;
> +}
> +
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
> +{
> +	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
> +	    agent_id != OCP_TARGET_AGENT)) {
> +		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> +		return -EINVAL;
> +	};
> +
> +	if (r == 0)
> +		pr_debug("OMAP PM: remove min bus tput constraint: "
> +			 "dev %s for agent_id %d\n", dev_name(dev), agent_id);
> +	else
> +		pr_debug("OMAP PM: add min bus tput constraint: "
> +			 "dev %s for agent_id %d: rate %ld KiB\n",
> +			 dev_name(dev), agent_id, r);
> +
> +	/*
> +	 * This code should model the interconnect and compute the
> +	 * required clock frequency, convert that to a VDD2 OPP ID, then
> +	 * set the VDD2 OPP appropriately.
> +	 *
> +	 * TI CDP code can call constraint_set here on the VDD2 OPP.
> +	 */
> +
> +	return 0;
> +}
> +
> +int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
> +				   long t)
> +{
> +	if (!req_dev || !dev || t < -1) {
> +		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> +		return -EINVAL;
> +	};
> +
> +	if (t == -1)
> +		pr_debug("OMAP PM: remove max device latency constraint: "
> +			 "dev %s\n", dev_name(dev));
> +	else
> +		pr_debug("OMAP PM: add max device latency constraint: "
> +			 "dev %s, t = %ld usec\n", dev_name(dev), t);
> +
> +	/*
> +	 * For current Linux, this needs to map the device to a
> +	 * powerdomain, then go through the list of current max lat
> +	 * constraints on that powerdomain and find the smallest.  If
> +	 * the latency constraint has changed, the code should
> +	 * recompute the state to enter for the next powerdomain
> +	 * state.  Conceivably, this code should also determine
> +	 * whether to actually disable the device clocks or not,
> +	 * depending on how long it takes to re-enable the clocks.
> +	 *
> +	 * TI CDP code can call constraint_set here.
> +	 */
> +
> +	return 0;
> +}
> +
> +int omap_pm_set_max_sdma_lat(struct device *dev, long t)
> +{
> +	if (!dev || t < -1) {
> +		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> +		return -EINVAL;
> +	};
> +
> +	if (t == -1)
> +		pr_debug("OMAP PM: remove max DMA latency constraint: "
> +			 "dev %s\n", dev_name(dev));
> +	else
> +		pr_debug("OMAP PM: add max DMA latency constraint: "
> +			 "dev %s, t = %ld usec\n", dev_name(dev), t);
> +
> +	/*
> +	 * For current Linux PM QOS params, this code should scan the
> +	 * list of maximum CPU and DMA latencies and select the
> +	 * smallest, then set cpu_dma_latency pm_qos_param
> +	 * accordingly.
> +	 *
> +	 * For future Linux PM QOS params, with separate CPU and DMA
> +	 * latency params, this code should just set the dma_latency param.
> +	 *
> +	 * TI CDP code can call constraint_set here.
> +	 */
> +
> +	return 0;
> +}
> +
> +int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
> +{
> +	if (!dev || !c || r < 0) {
> +		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> +		return -EINVAL;
> +	}
> +
> +	if (r == 0)
> +		pr_debug("OMAP PM: remove min clk rate constraint: "
> +			 "dev %s\n", dev_name(dev));
> +	else
> +		pr_debug("OMAP PM: add min clk rate constraint: "
> +			 "dev %s, rate = %ld Hz\n", dev_name(dev), r);
> +
> +	/*
> +	 * Code in a real implementation should keep track of these
> +	 * constraints on the clock, and determine the highest minimum
> +	 * clock rate.  It should iterate over each OPP and determine
> +	 * whether the OPP will result in a clock rate that would
> +	 * satisfy this constraint (and any other PM constraint in effect
> +	 * at that time).  Once it finds the lowest-voltage OPP that
> +	 * meets those conditions, it should switch to it, or return
> +	 * an error if the code is not capable of doing so.
> +	 */
> +
> +	return 0;
> +}
> +
> +/*
> + * DSP Bridge-specific constraints
> + */
> +
> +const struct omap_opp *omap_pm_dsp_get_opp_table(void)
> +{
> +	pr_debug("OMAP PM: DSP request for OPP table\n");
> +
> +	/*
> +	 * Return DSP frequency table here:  The final item in the
> +	 * array should have .rate = .opp_id = 0.
> +	 */
> +
> +	return NULL;
> +}
> +
> +void omap_pm_dsp_set_min_opp(u8 opp_id)
> +{
> +	if (opp_id == 0) {
> +		WARN_ON(1);
> +		return;
> +	}
> +
> +	pr_debug("OMAP PM: DSP requests minimum VDD1 OPP to be %d\n", opp_id);
> +
> +	/*
> +	 *
> +	 * For l-o dev tree, our VDD1 clk is keyed on OPP ID, so we
> +	 * can just test to see which is higher, the CPU's desired OPP
> +	 * ID or the DSP's desired OPP ID, and use whichever is
> +	 * highest.
> +	 *
> +	 * In CDP12.14+, the VDD1 OPP custom clock that controls the DSP
> +	 * rate is keyed on MPU speed, not the OPP ID.  So we need to
> +	 * map the OPP ID to the MPU speed for use with clk_set_rate()
> +	 * if it is higher than the current OPP clock rate.
> +	 *
> +	 */
> +}
> +
> +
> +u8 omap_pm_dsp_get_opp(void)
> +{
> +	pr_debug("OMAP PM: DSP requests current DSP OPP ID\n");
> +
> +	/*
> +	 * For l-o dev tree, call clk_get_rate() on VDD1 OPP clock
> +	 *
> +	 * CDP12.14+:
> +	 * Call clk_get_rate() on the OPP custom clock, map that to an
> +	 * OPP ID using the tables defined in board-*.c/chip-*.c files.
> +	 */
> +
> +	return 0;
> +}
> +
> +/*
> + * CPUFreq-originated constraint
> + *
> + * In the future, this should be handled by custom OPP clocktype
> + * functions.
> + */
> +
> +struct cpufreq_frequency_table **omap_pm_cpu_get_freq_table(void)
> +{
> +	pr_debug("OMAP PM: CPUFreq request for frequency table\n");
> +
> +	/*
> +	 * Return CPUFreq frequency table here: loop over
> +	 * all VDD1 clkrates, pull out the mpu_ck frequencies, build
> +	 * table
> +	 */
> +
> +	return NULL;
> +}
> +
> +void omap_pm_cpu_set_freq(unsigned long f)
> +{
> +	if (f == 0) {
> +		WARN_ON(1);
> +		return;
> +	}
> +
> +	pr_debug("OMAP PM: CPUFreq requests CPU frequency to be set to %lu\n",
> +		 f);
> +
> +	/*
> +	 * For l-o dev tree, determine whether MPU freq or DSP OPP id
> +	 * freq is higher.  Find the OPP ID corresponding to the
> +	 * higher frequency.  Call clk_round_rate() and clk_set_rate()
> +	 * on the OPP custom clock.
> +	 *
> +	 * CDP should just be able to set the VDD1 OPP clock rate here.
> +	 */
> +}
> +
> +unsigned long omap_pm_cpu_get_freq(void)
> +{
> +	pr_debug("OMAP PM: CPUFreq requests current CPU frequency\n");
> +
> +	/*
> +	 * Call clk_get_rate() on the mpu_ck.
> +	 */
> +
> +	return 0;
> +}
> +
> +/**
> + * omap_pm_enable_off_mode - notify OMAP PM that off-mode is enabled
> + *
> + * Intended for use only by OMAP PM core code to notify this layer
> + * that off mode has been enabled.
> + */
> +void omap_pm_enable_off_mode(void)
> +{
> +	off_mode_enabled = true;
> +}
> +
> +/**
> + * omap_pm_disable_off_mode - notify OMAP PM that off-mode is disabled
> + *
> + * Intended for use only by OMAP PM core code to notify this layer
> + * that off mode has been disabled.
> + */
> +void omap_pm_disable_off_mode(void)
> +{
> +	off_mode_enabled = false;
> +}
> +
> +/*
> + * Device context loss tracking
> + */
> +
> +#ifdef CONFIG_ARCH_OMAP2PLUS
> +
> +u32 omap_pm_get_dev_context_loss_count(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	u32 count;
> +
> +	if (WARN_ON(!dev))
> +		return 0;
> +
> +	if (dev->parent == &omap_device_parent) {
> +		count = omap_device_get_context_loss_count(pdev);
> +	} else {
> +		WARN_ONCE(off_mode_enabled, "omap_pm: using dummy context "
> +			  "loss counter; device %s should be converted to "
> +			  "omap_device", dev_name(dev));
> +		if (off_mode_enabled)
> +			dummy_context_loss_counter++;
> +		count = dummy_context_loss_counter;
> +	}
> +
> +	pr_debug("OMAP PM: context loss count for dev %s = %d\n",
> +		 dev_name(dev), count);
> +
> +	return count;
> +}
> +
> +#else
> +
> +u32 omap_pm_get_dev_context_loss_count(struct device *dev)
> +{
> +	return dummy_context_loss_counter;
> +}
> +
> +#endif
> +
> +/* Should be called before clk framework init */
> +int __init omap_pm_if_early_init(void)
> +{
> +	return 0;
> +}
> +
> +/* Must be called after clock framework is initialized */
> +int __init omap_pm_if_init(void)
> +{
> +	return 0;
> +}
> +
> +void omap_pm_if_exit(void)
> +{
> +	/* Deallocate CPUFreq frequency table here */
> +}
> +

[PATCH 2/2] OMAP: PM: implement devices wakeup latency constraints APIs

[Jean Pihet]

Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
creating similar APIs at the omap_device and omap_hwmod levels. The
omap_hwmod level call is the layer with access to the powerdomain
core, so it is the place where the powerdomain is queried to set and
release the constraints.

NOTE: only works for devices which have been converted to use
      omap_device/omap_hwmod.

Longer term, we could possibly remove this API from the OMAP PM layer,
and instead directly use the device level API.

The power domains get the next power state programmed directly in
the registers via pwrdm_wakeuplat_update_pwrst.

Note about PM QOS: the MPU and CORE power domains get the next power
state via cpuidle, which get the strongest wake-up latency constraint
by querying PM QOS. The usage of PM QOS is temporary, until a generic
solution is in place.

Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
and PM QOS frameworks.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Cc: Vibhore Vardhan <vvardhan@ti.com>
---
Based on khilman's pm-core branch

 arch/arm/mach-omap2/omap_hwmod.c              |   62 ++++++++-
 arch/arm/mach-omap2/powerdomain.c             |  197 +++++++++++++++++++++++++
 arch/arm/mach-omap2/powerdomain.h             |   39 +++++-
 arch/arm/mach-omap2/powerdomains3xxx_data.c   |   60 ++++++++
 arch/arm/plat-omap/include/plat/omap_device.h |    2 +
 arch/arm/plat-omap/include/plat/omap_hwmod.h  |    2 +
 arch/arm/plat-omap/omap-pm-constraints.c      |  121 +++++++--------
 arch/arm/plat-omap/omap_device.c              |   28 ++++
 8 files changed, 446 insertions(+), 65 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 028efda..bad8248 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -142,6 +142,7 @@
 #include "powerdomain.h"
 #include <plat/clock.h>
 #include <plat/omap_hwmod.h>
+#include <plat/omap_device.h>
 #include <plat/prcm.h>
 
 #include "cm2xxx_3xxx.h"
@@ -2267,10 +2268,69 @@ ohsps_unlock:
 }
 
 /**
+ * omap_hwmod_set_max_dev_wakeup_lat - set a device wake-up constraint
+ * @oh: the device of @oh to set a constraint on.
+ * @req_oh: the device of @req_oh is the requester of the constraint.
+ * @t: wakeup latency constraint (us). -1 removes the existing constraint.
+ *
+ * Query the powerdomain of @oh to set/release the wake-up constraint.
+ * @oh is used to determine which power domain to set a constraint on.
+ * @req_oh is used to record the requester for later update or removal
+ * of a constraint.
+ *
+ * Returns -EINVAL if @oh or @req_oh have no power domain, or the return
+ * code from the pwrdm function (pwrdm_wakeuplat_set/release_constraint)
+ * of the powerdomain assocated with @oh.
+ */
+int omap_hwmod_set_max_dev_wakeup_lat(struct omap_hwmod *req_oh,
+				      struct omap_hwmod *oh, long t)
+{
+	struct device *req_dev;
+	struct platform_device *req_pdev;
+	struct powerdomain *pwrdm;
+
+	pwrdm = omap_hwmod_get_pwrdm(oh);
+
+	/* Catch devices with undefined powerdomains */
+	if (!PTR_ERR(pwrdm)) {
+		pr_err("omap_hwmod: Error: could not find parent "
+			"powerdomain for %s\n", oh->name);
+		return -EINVAL;
+	}
+
+	req_pdev = &(req_oh->od->pdev);
+	if (!PTR_ERR(req_pdev)) {
+		pr_err("omap_hwmod: Error: pdev not found for oh %s\n",
+		       oh->name);
+		return -EINVAL;
+	}
+
+	req_dev = &(req_pdev->dev);
+	if (!PTR_ERR(req_dev)) {
+		pr_err("omap_hwmod: Error: device not found for oh %s\n",
+		       oh->name);
+		return -EINVAL;
+	}
+
+	/* Call set/release_constraint for the given pwrdm */
+	if (t == -1) {
+		pr_debug("omap_hwmod: remove max device latency constraint: "
+			 "oh %s, pwrdm %s, req by oh %s\n",
+			 oh->name, pwrdm->name, req_oh->name);
+	} else {
+		pr_debug("omap_hwmod: add max device latency constraint: "
+			 "oh %s, t = %ld usec, pwrdm %s, req by oh %s\n",
+			 oh->name, t, pwrdm->name, req_oh->name);
+	}
+
+	return pwrdm_wakeuplat_set_constraint(pwrdm, req_dev, t);
+}
+
+/**
  * omap_hwmod_get_context_loss_count - get lost context count
  * @oh: struct omap_hwmod *
  *
- * Query the powerdomain of of @oh to get the context loss
+ * Query the powerdomain of @oh to get the context loss
  * count for this device.
  *
  * Returns the context loss count of the powerdomain assocated with @oh
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index eaed0df..6fb4741 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -19,6 +19,8 @@
 #include <linux/list.h>
 #include <linux/errno.h>
 #include <linux/string.h>
+#include <linux/slab.h>
+
 #include "cm2xxx_3xxx.h"
 #include "prcm44xx.h"
 #include "cm44xx.h"
@@ -103,6 +105,13 @@ static int _pwrdm_register(struct powerdomain *pwrdm)
 	pwrdm->state = pwrdm_read_pwrst(pwrdm);
 	pwrdm->state_counter[pwrdm->state] = 1;
 
+	/* Initialize priority ordered list for wakeup latency constraint */
+	spin_lock_init(&pwrdm->wakeuplat_lock);
+	plist_head_init(&pwrdm->wakeuplat_dev_list, &pwrdm->wakeuplat_lock);
+
+	/* res_mutex protects res_list add and del ops */
+	mutex_init(&pwrdm->wakeuplat_mutex);
+
 	pr_debug("powerdomain: registered %s\n", pwrdm->name);
 
 	return 0;
@@ -176,6 +185,74 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
 	return 0;
 }
 
+/**
+ * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
+ * @pwrdm: struct powerdomain * to which requesting device belongs to.
+ *
+ * Finds the minimum allowed wake-up latency value from all entries
+ * in the list and the power domain power state needing the constraint.
+ * Programs a new target state if it is different from current power state.
+ *
+ * Only OMAP3xxx is supported for now
+ *
+ * Returns 0 upon success.
+ */
+static int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm)
+{
+	struct plist_node *node;
+	int ret = 0, new_state;
+	long min_latency = -1;
+
+	/* Find the strongest constraint from the plist */
+	if (!plist_head_empty(&pwrdm->wakeuplat_dev_list)) {
+		node = plist_first(&pwrdm->wakeuplat_dev_list);
+		min_latency = node->prio;
+	}
+
+	/* Find power state with wakeup latency < minimum constraint. */
+	for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
+		if (min_latency == -1 ||
+		    pwrdm->wakeup_lat[new_state] <= min_latency)
+			break;
+	}
+
+	switch (new_state) {
+	case PWRDM_FUNC_PWRST_OFF:
+		new_state = PWRDM_POWER_OFF;
+		break;
+	case PWRDM_FUNC_PWRST_OSWR:
+		if (cpu_is_omap34xx())
+			pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
+		new_state = PWRDM_POWER_RET;
+		break;
+	case PWRDM_FUNC_PWRST_CSWR:
+		if (cpu_is_omap34xx())
+			pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
+		new_state = PWRDM_POWER_RET;
+		break;
+	case PWRDM_FUNC_PWRST_ON:
+		new_state = PWRDM_POWER_ON;
+		break;
+	default:
+		pr_warn("powerdomain: requested latency constraint not "
+			"supported %s set to ON state\n", pwrdm->name);
+		new_state = PWRDM_POWER_ON;
+		break;
+	}
+
+	if (pwrdm_read_pwrst(pwrdm) != new_state) {
+		if (cpu_is_omap34xx())
+			ret = omap_set_pwrdm_state(pwrdm, new_state);
+	}
+
+	pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
+		 "min_latency=%ld, set_state=%d\n", pwrdm->name,
+		 pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
+		 pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
+
+	return ret;
+}
+
 /* Public functions */
 
 /**
@@ -910,6 +987,126 @@ int pwrdm_post_transition(void)
 	return 0;
 }
 
+/*
+ * Test if the current powerdomain is MPU or CORE
+ *
+ * This function is only used by pwrdm_wakeuplat_set_constraint
+ * which applies the MPU and CORE power domains constraints using PM QOS.
+ *
+ * This will disappear when all power domains will be controlled directly
+ * from the wake-up latency constraints framework
+ */
+static inline int is_pwrdm_mpu_or_core(struct powerdomain *pwrdm)
+{
+	if ((strncmp(pwrdm->name, "mpu_pwrdm", 9) == 0) ||
+	    (strncmp(pwrdm->name, "core_pwrdm", 10) == 0))
+		return 1;
+	else
+		return 0;
+}
+
+/*
+ * pwrdm_wakeuplat_set_constraint - Set/update/remove powerdomain wakeup
+ * latency constraint
+ * @pwrdm: struct powerdomain * to which requesting device belongs to
+ * @dev: struct device * of requesting device
+ * @t: wakeup latency constraint in microseconds. The value of -1 removes
+ * the constraint
+ *
+ * Constraint set/update: Adds new entry to powerdomain's wakeup latency
+ * constraint list.
+ * If the requesting device already exists in the list, old value is
+ * overwritten. Checks whether current power state is still adequate.
+ *
+ * Constraint removal: Removes device's entry from powerdomain's wakeup
+ * latency constraint list. Checks whether current power state is still
+ * adequate.
+ *
+ * Note about PM QOS: the MPU and CORE power domains get the next power
+ * state via cpuidle, which get the strongest wake-up latency constraint
+ * by querying PM QOS. The usage of PM QOS is temporary, until a generic
+ * solution is in place.
+ * The power domains other then MPU and CORE get the next power state
+ * programmed directly in the registers via pwrdm_wakeuplat_update_pwrst.
+ *
+ * Returns -EINVAL if the powerdomain or device pointer is NULL or
+ * no such entry exists in the list, or -ENOMEM if kmalloc fails, or
+ * returns 0 upon success.
+ */
+int pwrdm_wakeuplat_set_constraint(struct powerdomain *pwrdm,
+				   struct device *req_dev, long t)
+{
+	struct  wakeuplat_dev_list *user;
+	int found = 0, ret = 0;
+
+	if (!pwrdm || !req_dev) {
+		WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	}
+
+	mutex_lock(&pwrdm->wakeuplat_mutex);
+
+	plist_for_each_entry(user, &pwrdm->wakeuplat_dev_list, node) {
+		if (user->dev == req_dev) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (t >= 0) {
+		/* Add new entry to the list or update existing request */
+		if (found && user->constraint_us == t) {
+			goto exit_set;
+		} else if (!found) {
+			user = kzalloc(sizeof(struct wakeuplat_dev_list),
+				       GFP_KERNEL);
+			if (!user) {
+				pr_err("powerdomain: FATAL ERROR: kzalloc "
+				       "failed\n");
+				ret = -ENOMEM;
+				goto exit_set;
+			}
+			user->dev = req_dev;
+		} else {
+			plist_del(&user->node, &pwrdm->wakeuplat_dev_list);
+			if (is_pwrdm_mpu_or_core(pwrdm))
+				pm_qos_remove_request(&(user->pm_qos_request));
+		}
+
+		plist_node_init(&user->node, t);
+		plist_add(&user->node, &pwrdm->wakeuplat_dev_list);
+		user->node.prio = user->constraint_us = t;
+		if (is_pwrdm_mpu_or_core(pwrdm))
+			pm_qos_add_request(&(user->pm_qos_request),
+					   PM_QOS_CPU_DMA_LATENCY, t);
+	} else {
+		/* Remove the constraint from the list */
+		if (!found) {
+			pr_err("OMAP PM: Error: no prior constraint to "
+			       "release\n");
+			ret = -EINVAL;
+			goto exit_set;
+		}
+
+		if (is_pwrdm_mpu_or_core(pwrdm))
+			pm_qos_remove_request(&(user->pm_qos_request));
+		plist_del(&user->node, &pwrdm->wakeuplat_dev_list);
+		kfree(user);
+	}
+
+	/*
+	 * Constraints on MPU and CORE are passed to PM QOS while other power
+	 * domains get the next power state programmed directly
+	 */
+	if (!(is_pwrdm_mpu_or_core(pwrdm)))
+		ret = pwrdm_wakeuplat_update_pwrst(pwrdm);
+
+exit_set:
+	mutex_unlock(&pwrdm->wakeuplat_mutex);
+
+	return ret;
+}
+
 /**
  * pwrdm_get_context_loss_count - get powerdomain's context loss count
  * @pwrdm: struct powerdomain * to wait for
diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
index 0b7a357..98eea82 100644
--- a/arch/arm/mach-omap2/powerdomain.h
+++ b/arch/arm/mach-omap2/powerdomain.h
@@ -19,7 +19,10 @@
 
 #include <linux/types.h>
 #include <linux/list.h>
-
+#include <linux/plist.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/pm_qos_params.h>
 #include <linux/atomic.h>
 
 #include <plat/cpu.h>
@@ -46,6 +49,15 @@
 
 #define PWRSTS_OFF_RET_ON	(PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))
 
+/* Powerdomain functional power states */
+#define PWRDM_FUNC_PWRST_OFF	0x0
+#define PWRDM_FUNC_PWRST_OSWR	0x1
+#define PWRDM_FUNC_PWRST_CSWR	0x2
+#define PWRDM_FUNC_PWRST_ON	0x3
+
+#define PWRDM_MAX_FUNC_PWRSTS	4
+
+#define UNSUP_STATE		-1
 
 /* Powerdomain flags */
 #define PWRDM_HAS_HDWR_SAR	(1 << 0) /* hardware save-and-restore support */
@@ -96,6 +108,12 @@ struct powerdomain;
  * @state_counter:
  * @timer:
  * @state_timer:
+ * @wakeup_lat: wakeup latencies for possible powerdomain power states
+ * Note about the wakeup latencies ordering: the values must be sorted
+ *  in decremental order
+ * @wakeuplat_lock: spinlock for plist
+ * @wakeuplat_dev_list: plist_head linking all devices placing constraint
+ * @wakeuplat_mutex: mutex to protect per powerdomain list ops
  *
  * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
  */
@@ -121,6 +139,22 @@ struct powerdomain {
 	s64 timer;
 	s64 state_timer[PWRDM_MAX_PWRSTS];
 #endif
+	const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
+	spinlock_t wakeuplat_lock;
+	struct plist_head wakeuplat_dev_list;
+	struct mutex wakeuplat_mutex;
+};
+
+/*
+ * Linked list for the power domains wakeup latencies constraints
+ * The PM QOS handle is only used to control the MPU and CORE power
+ * domains states; to be removed when a generic solution is in place.
+*/
+struct wakeuplat_dev_list {
+	struct device			*dev;
+	unsigned long			constraint_us;
+	struct plist_node		node;
+	struct pm_qos_request_list	pm_qos_request;
 };
 
 /**
@@ -210,6 +244,9 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
 int pwrdm_pre_transition(void);
 int pwrdm_post_transition(void);
 int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
+
+int pwrdm_wakeuplat_set_constraint(struct powerdomain *pwrdm,
+				   struct device *req_dev, long t);
 u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
 
 extern void omap2xxx_powerdomains_init(void);
diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
index e1bec56..4f7e44d 100644
--- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
+++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
@@ -52,6 +52,12 @@ static struct powerdomain iva2_pwrdm = {
 		[2] = PWRSTS_OFF_ON,
 		[3] = PWRDM_POWER_ON,
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 1100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 350,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain mpu_3xxx_pwrdm = {
@@ -68,6 +74,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRSTS_OFF_ON,
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 95,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 45,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 /*
@@ -98,6 +110,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
 		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
 		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 60,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain core_3xxx_es3_1_pwrdm = {
@@ -121,6 +139,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
 		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
 		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 60,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain dss_pwrdm = {
@@ -136,6 +160,12 @@ static struct powerdomain dss_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 70,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 20,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 /*
@@ -157,6 +187,12 @@ static struct powerdomain sgx_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 1000,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain cam_pwrdm = {
@@ -172,6 +208,12 @@ static struct powerdomain cam_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 850,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 35,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain per_pwrdm = {
@@ -187,6 +229,12 @@ static struct powerdomain per_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 200,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 110,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain emu_pwrdm = {
@@ -201,6 +249,12 @@ static struct powerdomain neon_pwrdm = {
 	.omap_chip	  = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
 	.pwrsts		  = PWRSTS_OFF_RET_ON,
 	.pwrsts_logic_ret = PWRDM_POWER_RET,
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 200,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 35,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain usbhost_pwrdm = {
@@ -223,6 +277,12 @@ static struct powerdomain usbhost_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 800,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 150,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain dpll1_pwrdm = {
diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
index e4c349f..5da6b47 100644
--- a/arch/arm/plat-omap/include/plat/omap_device.h
+++ b/arch/arm/plat-omap/include/plat/omap_device.h
@@ -107,6 +107,8 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
 int omap_device_align_pm_lat(struct platform_device *pdev,
 			     u32 new_wakeup_lat_limit);
 struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
+int omap_device_set_max_dev_wakeup_lat(struct platform_device *req_pdev,
+				       struct platform_device *pdev, long t);
 u32 omap_device_get_context_loss_count(struct platform_device *pdev);
 
 /* Other */
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 4f5b23e..7fcf168 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -595,6 +595,8 @@ int omap_hwmod_for_each_by_class(const char *classname,
 				 void *user);
 
 int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state);
+int omap_hwmod_set_max_dev_wakeup_lat(struct omap_hwmod *req_oh,
+				      struct omap_hwmod *oh, long t);
 u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh);
 
 /*
diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
index c8b4e4c..df24e5e 100644
--- a/arch/arm/plat-omap/omap-pm-constraints.c
+++ b/arch/arm/plat-omap/omap-pm-constraints.c
@@ -24,6 +24,7 @@
 /* Interface documentation is in mach/omap-pm.h */
 #include <plat/omap-pm.h>
 #include <plat/omap_device.h>
+#include <plat/common.h>
 
 static bool off_mode_enabled;
 static u32 dummy_context_loss_counter;
@@ -32,34 +33,6 @@ static u32 dummy_context_loss_counter;
  * Device-driver-originated constraints (via board-*.c files)
  */
 
-int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
-{
-	if (!dev || t < -1) {
-		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
-		return -EINVAL;
-	};
-
-	if (t == -1)
-		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
-			 "dev %s\n", dev_name(dev));
-	else
-		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
-
-	/*
-	 * For current Linux, this needs to map the MPU to a
-	 * powerdomain, then go through the list of current max lat
-	 * constraints on the MPU and find the smallest.  If
-	 * the latency constraint has changed, the code should
-	 * recompute the state to enter for the next powerdomain
-	 * state.
-	 *
-	 * TI CDP code can call constraint_set here.
-	 */
-
-	return 0;
-}
-
 int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
 {
 	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
@@ -87,64 +60,86 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
 	return 0;
 }
 
+/*
+ * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
+ * constraints
+ */
 int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
 				   long t)
 {
+	struct platform_device *pdev, *req_pdev;
+	int ret = 0;
+
 	if (!req_dev || !dev || t < -1) {
 		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
 		return -EINVAL;
+	}
+
+	/* Look for the platform devices */
+	pdev = to_platform_device(dev);
+	req_pdev = to_platform_device(req_dev);
+
+	/* Try to catch non platform devices. */
+	if ((pdev->name == NULL) || (req_pdev->name == NULL)) {
+		pr_err("OMAP-PM set_wakeup_lat: Error: platform devices "
+		       "not valid\n");
+		return -EINVAL;
+	} else {
+		/* Call the omap_device API */
+		ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
+	}
+
+	return ret;
+}
+
+/*
+ * omap_pm_set_max_mpu_wakeup_lat - set/release MPU wake-up latency
+ * constraints
+ *
+ * Maps to omap_pm_set_max_dev_wakeup_lat with the MPU device as constraints
+ * target.
+ */
+int omap_pm_set_max_mpu_wakeup_lat(struct device *req_dev, long t)
+{
+	if (!req_dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
 	};
 
 	if (t == -1)
-		pr_debug("OMAP PM: remove max device latency constraint: "
-			 "dev %s\n", dev_name(dev));
+		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
+			 "dev %s\n", dev_name(req_dev));
 	else
-		pr_debug("OMAP PM: add max device latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
-
-	/*
-	 * For current Linux, this needs to map the device to a
-	 * powerdomain, then go through the list of current max lat
-	 * constraints on that powerdomain and find the smallest.  If
-	 * the latency constraint has changed, the code should
-	 * recompute the state to enter for the next powerdomain
-	 * state.  Conceivably, this code should also determine
-	 * whether to actually disable the device clocks or not,
-	 * depending on how long it takes to re-enable the clocks.
-	 *
-	 * TI CDP code can call constraint_set here.
-	 */
+		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(req_dev), t);
 
-	return 0;
+	return omap_pm_set_max_dev_wakeup_lat(req_dev,
+					      omap2_get_mpuss_device(), t);
 }
 
-int omap_pm_set_max_sdma_lat(struct device *dev, long t)
+/*
+ * omap_pm_set_max_sdma_lat - set/release SDMA start latency
+ * constraints
+ *
+ * Currenlt maps to omap_pm_set_max_dev_wakeup_lat with the L3 device as
+ * constraints target.
+ */
+int omap_pm_set_max_sdma_lat(struct device *req_dev, long t)
 {
-	if (!dev || t < -1) {
+	if (!req_dev || t < -1) {
 		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
 		return -EINVAL;
 	};
 
 	if (t == -1)
 		pr_debug("OMAP PM: remove max DMA latency constraint: "
-			 "dev %s\n", dev_name(dev));
+			 "dev %s\n", dev_name(req_dev));
 	else
 		pr_debug("OMAP PM: add max DMA latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+			 "dev %s, t = %ld usec\n", dev_name(req_dev), t);
 
-	/*
-	 * For current Linux PM QOS params, this code should scan the
-	 * list of maximum CPU and DMA latencies and select the
-	 * smallest, then set cpu_dma_latency pm_qos_param
-	 * accordingly.
-	 *
-	 * For future Linux PM QOS params, with separate CPU and DMA
-	 * latency params, this code should just set the dma_latency param.
-	 *
-	 * TI CDP code can call constraint_set here.
-	 */
-
-	return 0;
+	return omap_pm_set_max_dev_wakeup_lat(req_dev,
+					      omap2_get_l3_device(), t);
 }
 
 int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index 9bbda9a..43dba02 100644
--- a/arch/arm/plat-omap/omap_device.c
+++ b/arch/arm/plat-omap/omap_device.c
@@ -296,6 +296,34 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
 /* Public functions for use by core code */
 
 /**
+ * omap_device_set_max_dev_wakeup_lat - set/release a device constraint
+ * @od: struct omap_device *
+ * @req_od: struct omap_device *
+ *
+ * Using the primary hwmod, set/release a device constraint for the pdev
+ * device, requested by the req_pdev device.
+ *
+ * If any hwmods exist for the omap_device assoiated with @pdev and @req_pdev,
+ * set/release the constraint for the corresponding hwmods, otherwise return
+ * -EINVAL.
+ */
+int omap_device_set_max_dev_wakeup_lat(struct platform_device *req_pdev,
+				       struct platform_device *pdev, long t)
+{
+	struct omap_device *od, *req_od;
+	u32 ret = -EINVAL;
+
+	od = _find_by_pdev(pdev);
+	req_od = _find_by_pdev(req_pdev);
+
+	if ((od->hwmods_cnt) && (req_od->hwmods_cnt))
+		ret = omap_hwmod_set_max_dev_wakeup_lat(req_od->hwmods[0],
+							od->hwmods[0], t);
+
+	return ret;
+}
+
+/**
  * omap_device_get_context_loss_count - get lost context count
  * @od: struct omap_device *
  *
-- 
1.7.2.3

Re: [PATCH 2/2] OMAP: PM: implement devices wakeup latency constraints APIs

[Kevin Hilman]

Jean Pihet <jean.pihet@newoldbits.com> writes:

> Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
> creating similar APIs at the omap_device and omap_hwmod levels. The
> omap_hwmod level call is the layer with access to the powerdomain
> core, so it is the place where the powerdomain is queried to set and
> release the constraints.
>
> NOTE: only works for devices which have been converted to use
>       omap_device/omap_hwmod.
>
> Longer term, we could possibly remove this API from the OMAP PM layer,
> and instead directly use the device level API.
>
> The power domains get the next power state programmed directly in
> the registers via pwrdm_wakeuplat_update_pwrst.
>
> Note about PM QOS: the MPU and CORE power domains get the next power
> state via cpuidle, which get the strongest wake-up latency constraint
> by querying PM QOS. The usage of PM QOS is temporary, until a generic
> solution is in place.
>
> Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
> and PM QOS frameworks.

I haven't got to a detailed review of this code yet, but did do some
experiements and have some general comments on the code/design to get
started.

Also, I had a problem doing a real dumb test until I figured out the
problem with the init sequence.  I tried setting a constraint in the
device init code for UART (mach-omap2/serial.c:omap_serial_init_port()),
and then I realized that that runs before
mach-omap2/pm34xx.c:pwrdms_setup() which also calls
omap_set_pwrdm_state() for each powerdomain to initialize.

Also, for debug purposes, it might be useful to have a per-device sysfs
interface to setting this wakeup latency constraint.  Something like

   /sys/devices/platform/omap/.../power/wakeup_latency

I'm not sure exactly what to set the requesting device to though.  

As far as implementation goes, you've so far implemented only wakeup
latencies, but not througput.  When you implement throughput you will
have to duplicate large parts of this code and data structures for
throughput, and if ever add some other constraint (frequency, voltage)
it would need to be duplicated again.

Maybe now is the time to consider an interface to add a generic
per-device constraint, with a type (latency, throughput, etc.), or
"class" as it's called in PM QoS.  For now the type/class does not need
to be exposed externally, but will make implementing new constraint
types much easer.

Some other comments below...

> Signed-off-by: Jean Pihet <j-pihet@ti.com>
> Cc: Vibhore Vardhan <vvardhan@ti.com>
> ---
> Based on khilman's pm-core branch
>
>  arch/arm/mach-omap2/omap_hwmod.c              |   62 ++++++++-
>  arch/arm/mach-omap2/powerdomain.c             |  197 +++++++++++++++++++++++++
>  arch/arm/mach-omap2/powerdomain.h             |   39 +++++-
>  arch/arm/mach-omap2/powerdomains3xxx_data.c   |   60 ++++++++
>  arch/arm/plat-omap/include/plat/omap_device.h |    2 +
>  arch/arm/plat-omap/include/plat/omap_hwmod.h  |    2 +
>  arch/arm/plat-omap/omap-pm-constraints.c      |  121 +++++++--------
>  arch/arm/plat-omap/omap_device.c              |   28 ++++
>  8 files changed, 446 insertions(+), 65 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index 028efda..bad8248 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -142,6 +142,7 @@
>  #include "powerdomain.h"
>  #include <plat/clock.h>
>  #include <plat/omap_hwmod.h>
> +#include <plat/omap_device.h>
>  #include <plat/prcm.h>
>  
>  #include "cm2xxx_3xxx.h"
> @@ -2267,10 +2268,69 @@ ohsps_unlock:
>  }
>  
>  /**
> + * omap_hwmod_set_max_dev_wakeup_lat - set a device wake-up constraint
> + * @oh: the device of @oh to set a constraint on.
> + * @req_oh: the device of @req_oh is the requester of the constraint.
> + * @t: wakeup latency constraint (us). -1 removes the existing constraint.
> + *
> + * Query the powerdomain of @oh to set/release the wake-up constraint.
> + * @oh is used to determine which power domain to set a constraint on.
> + * @req_oh is used to record the requester for later update or removal
> + * of a constraint.
> + *
> + * Returns -EINVAL if @oh or @req_oh have no power domain, or the return
> + * code from the pwrdm function (pwrdm_wakeuplat_set/release_constraint)
> + * of the powerdomain assocated with @oh.
> + */
> +int omap_hwmod_set_max_dev_wakeup_lat(struct omap_hwmod *req_oh,
> +				      struct omap_hwmod *oh, long t)
> +{
> +	struct device *req_dev;
> +	struct platform_device *req_pdev;
> +	struct powerdomain *pwrdm;
> +
> +	pwrdm = omap_hwmod_get_pwrdm(oh);
> +
> +	/* Catch devices with undefined powerdomains */
> +	if (!PTR_ERR(pwrdm)) {
> +		pr_err("omap_hwmod: Error: could not find parent "
> +			"powerdomain for %s\n", oh->name);
> +		return -EINVAL;
> +	}
> +
> +	req_pdev = &(req_oh->od->pdev);
> +	if (!PTR_ERR(req_pdev)) {
> +		pr_err("omap_hwmod: Error: pdev not found for oh %s\n",
> +		       oh->name);
> +		return -EINVAL;
> +	}
> +
> +	req_dev = &(req_pdev->dev);
> +	if (!PTR_ERR(req_dev)) {
> +		pr_err("omap_hwmod: Error: device not found for oh %s\n",
> +		       oh->name);
> +		return -EINVAL;
> +	}
> +
> +	/* Call set/release_constraint for the given pwrdm */
> +	if (t == -1) {
> +		pr_debug("omap_hwmod: remove max device latency constraint: "
> +			 "oh %s, pwrdm %s, req by oh %s\n",
> +			 oh->name, pwrdm->name, req_oh->name);
> +	} else {
> +		pr_debug("omap_hwmod: add max device latency constraint: "
> +			 "oh %s, t = %ld usec, pwrdm %s, req by oh %s\n",
> +			 oh->name, t, pwrdm->name, req_oh->name);
> +	}
> +
> +	return pwrdm_wakeuplat_set_constraint(pwrdm, req_dev, t);
> +}
> +
> +/**
>   * omap_hwmod_get_context_loss_count - get lost context count
>   * @oh: struct omap_hwmod *
>   *
> - * Query the powerdomain of of @oh to get the context loss
> + * Query the powerdomain of @oh to get the context loss
>   * count for this device.
>   *
>   * Returns the context loss count of the powerdomain assocated with @oh
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index eaed0df..6fb4741 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -19,6 +19,8 @@
>  #include <linux/list.h>
>  #include <linux/errno.h>
>  #include <linux/string.h>
> +#include <linux/slab.h>
> +
>  #include "cm2xxx_3xxx.h"
>  #include "prcm44xx.h"
>  #include "cm44xx.h"
> @@ -103,6 +105,13 @@ static int _pwrdm_register(struct powerdomain *pwrdm)
>  	pwrdm->state = pwrdm_read_pwrst(pwrdm);
>  	pwrdm->state_counter[pwrdm->state] = 1;
>  
> +	/* Initialize priority ordered list for wakeup latency constraint */
> +	spin_lock_init(&pwrdm->wakeuplat_lock);
> +	plist_head_init(&pwrdm->wakeuplat_dev_list, &pwrdm->wakeuplat_lock);
> +
> +	/* res_mutex protects res_list add and del ops */
> +	mutex_init(&pwrdm->wakeuplat_mutex);
> +
>  	pr_debug("powerdomain: registered %s\n", pwrdm->name);
>  
>  	return 0;
> @@ -176,6 +185,74 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
>  	return 0;
>  }
>  
> +/**
> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
> + *
> + * Finds the minimum allowed wake-up latency value from all entries
> + * in the list and the power domain power state needing the constraint.
> + * Programs a new target state if it is different from current power state.
> + *
> + * Only OMAP3xxx is supported for now
> + *
> + * Returns 0 upon success.
> + */
> +static int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm)
> +{
> +	struct plist_node *node;
> +	int ret = 0, new_state;
> +	long min_latency = -1;
> +
> +	/* Find the strongest constraint from the plist */
> +	if (!plist_head_empty(&pwrdm->wakeuplat_dev_list)) {
> +		node = plist_first(&pwrdm->wakeuplat_dev_list);
> +		min_latency = node->prio;
> +	}
> +
> +	/* Find power state with wakeup latency < minimum constraint. */
> +	for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
> +		if (min_latency == -1 ||
> +		    pwrdm->wakeup_lat[new_state] <= min_latency)
> +			break;
> +	}
> +
> +	switch (new_state) {
> +	case PWRDM_FUNC_PWRST_OFF:
> +		new_state = PWRDM_POWER_OFF;
> +		break;
> +	case PWRDM_FUNC_PWRST_OSWR:
> +		if (cpu_is_omap34xx())
> +			pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);

cpu_is_* checks here aren't right.

You should use SoC specific function pointers as are done for many of the
other powerdomain calls after Rajendra's splitup series.

> +		new_state = PWRDM_POWER_RET;
> +		break;
> +	case PWRDM_FUNC_PWRST_CSWR:
> +		if (cpu_is_omap34xx())
> +			pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
> +		new_state = PWRDM_POWER_RET;
> +		break;
> +	case PWRDM_FUNC_PWRST_ON:
> +		new_state = PWRDM_POWER_ON;
> +		break;
> +	default:
> +		pr_warn("powerdomain: requested latency constraint not "
> +			"supported %s set to ON state\n", pwrdm->name);
> +		new_state = PWRDM_POWER_ON;
> +		break;
> +	}
> +
> +	if (pwrdm_read_pwrst(pwrdm) != new_state) {
> +		if (cpu_is_omap34xx())
> +			ret = omap_set_pwrdm_state(pwrdm, new_state);
> +	}
> +
> +	pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
> +		 "min_latency=%ld, set_state=%d\n", pwrdm->name,
> +		 pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
> +		 pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
> +
> +	return ret;
> +}
> +

[...]

> diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
> index e1bec56..4f7e44d 100644
> --- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
> +++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
> @@ -52,6 +52,12 @@ static struct powerdomain iva2_pwrdm = {
>  		[2] = PWRSTS_OFF_ON,
>  		[3] = PWRDM_POWER_ON,
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 1100,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 350,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain mpu_3xxx_pwrdm = {
> @@ -68,6 +74,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRSTS_OFF_ON,
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 95,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 45,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  /*
> @@ -98,6 +110,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
>  		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>  		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 100,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 60,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain core_3xxx_es3_1_pwrdm = {
> @@ -121,6 +139,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
>  		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>  		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 100,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 60,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain dss_pwrdm = {
> @@ -136,6 +160,12 @@ static struct powerdomain dss_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 70,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 20,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  /*
> @@ -157,6 +187,12 @@ static struct powerdomain sgx_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 1000,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain cam_pwrdm = {
> @@ -172,6 +208,12 @@ static struct powerdomain cam_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 850,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 35,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain per_pwrdm = {
> @@ -187,6 +229,12 @@ static struct powerdomain per_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 200,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 110,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain emu_pwrdm = {
> @@ -201,6 +249,12 @@ static struct powerdomain neon_pwrdm = {
>  	.omap_chip	  = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
>  	.pwrsts		  = PWRSTS_OFF_RET_ON,
>  	.pwrsts_logic_ret = PWRDM_POWER_RET,
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 200,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 35,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain usbhost_pwrdm = {
> @@ -223,6 +277,12 @@ static struct powerdomain usbhost_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 800,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 150,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };

A summary about where the latency numbers for each powerdomain come from
would be useful.

[...]

> @@ -87,64 +60,86 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>  	return 0;
>  }
>  
> +/*
> + * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
> + * constraints
> + */
>  int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
>  				   long t)
>  {
> +	struct platform_device *pdev, *req_pdev;
> +	int ret = 0;
> +
>  	if (!req_dev || !dev || t < -1) {
>  		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>  		return -EINVAL;
> +	}
> +
> +	/* Look for the platform devices */
> +	pdev = to_platform_device(dev);
> +	req_pdev = to_platform_device(req_dev);
> +
> +	/* Try to catch non platform devices. */
> +	if ((pdev->name == NULL) || (req_pdev->name == NULL)) {
> +		pr_err("OMAP-PM set_wakeup_lat: Error: platform devices "
> +		       "not valid\n");
> +		return -EINVAL;
> +	} else {
> +		/* Call the omap_device API */
> +		ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
> +	}

I don't think a NULL name check is the right sanity check here.  WHat
you really need to know is whether the target device is an omap_device.
The requesting device can be anything (I think.)

Here's a simpler check:

	if (pdev->dev->parent == &omap_device_parent)
		ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
	else
		...

                        
> +	return ret;
> +}

Kevin

Re: [PATCH 2/2] OMAP: PM: implement devices wakeup latency constraints APIs

[Jean Pihet]

On Tue, Mar 8, 2011 at 3:15 AM, Kevin Hilman <khilman@ti.com> wrote:
> Jean Pihet <jean.pihet@newoldbits.com> writes:
>
>> Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
>> creating similar APIs at the omap_device and omap_hwmod levels. The
>> omap_hwmod level call is the layer with access to the powerdomain
>> core, so it is the place where the powerdomain is queried to set and
>> release the constraints.
>>
>> NOTE: only works for devices which have been converted to use
>>       omap_device/omap_hwmod.
>>
>> Longer term, we could possibly remove this API from the OMAP PM layer,
>> and instead directly use the device level API.
>>
>> The power domains get the next power state programmed directly in
>> the registers via pwrdm_wakeuplat_update_pwrst.
>>
>> Note about PM QOS: the MPU and CORE power domains get the next power
>> state via cpuidle, which get the strongest wake-up latency constraint
>> by querying PM QOS. The usage of PM QOS is temporary, until a generic
>> solution is in place.
>>
>> Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
>> and PM QOS frameworks.
>
> I haven't got to a detailed review of this code yet, but did do some
> experiements and have some general comments on the code/design to get
> started.
>
> Also, I had a problem doing a real dumb test until I figured out the
> problem with the init sequence.  I tried setting a constraint in the
> device init code for UART (mach-omap2/serial.c:omap_serial_init_port()),
> and then I realized that that runs before
> mach-omap2/pm34xx.c:pwrdms_setup() which also calls
> omap_set_pwrdm_state() for each powerdomain to initialize.
Do we need to change the behavior at init?

> Also, for debug purposes, it might be useful to have a per-device sysfs
> interface to setting this wakeup latency constraint.  Something like
>
>   /sys/devices/platform/omap/.../power/wakeup_latency
I do not see this as a debug interface but rather an API to the user space.
If that is the case there are some issues to deal with, cf. below.

> I'm not sure exactly what to set the requesting device to though.
And also, how to track the requesters? PM QOS is using a /dev node
that must be kept open as long as the constraints remains valid.

> As far as implementation goes, you've so far implemented only wakeup
> latencies, but not througput.  When you implement throughput you will
> have to duplicate large parts of this code and data structures for
> throughput, and if ever add some other constraint (frequency, voltage)
> it would need to be duplicated again.
>
> Maybe now is the time to consider an interface to add a generic
> per-device constraint, with a type (latency, throughput, etc.), or
> "class" as it's called in PM QoS.  For now the type/class does not need
> to be exposed externally, but will make implementing new constraint
> types much easer.
Ok that makes sense.
In the current patch the constraints plist is stored inside the
powerdomain structure. This does not apply to throughput, frequency
and voltage constraints.
Should the list constraint be managed in the OMAP PM layer instead of
in the power domain code? If so where to store the constraints?

> Some other comments below...
>
>> Signed-off-by: Jean Pihet <j-pihet@ti.com>
>> Cc: Vibhore Vardhan <vvardhan@ti.com>
>> ---
>> Based on khilman's pm-core branch
>>
>>  arch/arm/mach-omap2/omap_hwmod.c              |   62 ++++++++-
>>  arch/arm/mach-omap2/powerdomain.c             |  197 +++++++++++++++++++++++++
>>  arch/arm/mach-omap2/powerdomain.h             |   39 +++++-
>>  arch/arm/mach-omap2/powerdomains3xxx_data.c   |   60 ++++++++
>>  arch/arm/plat-omap/include/plat/omap_device.h |    2 +
>>  arch/arm/plat-omap/include/plat/omap_hwmod.h  |    2 +
>>  arch/arm/plat-omap/omap-pm-constraints.c      |  121 +++++++--------
>>  arch/arm/plat-omap/omap_device.c              |   28 ++++
>>  8 files changed, 446 insertions(+), 65 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
>> index 028efda..bad8248 100644
>> --- a/arch/arm/mach-omap2/omap_hwmod.c
>> +++ b/arch/arm/mach-omap2/omap_hwmod.c
>> @@ -142,6 +142,7 @@
>>  #include "powerdomain.h"
>>  #include <plat/clock.h>
>>  #include <plat/omap_hwmod.h>
>> +#include <plat/omap_device.h>
>>  #include <plat/prcm.h>
>>
>>  #include "cm2xxx_3xxx.h"
>> @@ -2267,10 +2268,69 @@ ohsps_unlock:
>>  }
>>
>>  /**
>> + * omap_hwmod_set_max_dev_wakeup_lat - set a device wake-up constraint
>> + * @oh: the device of @oh to set a constraint on.
>> + * @req_oh: the device of @req_oh is the requester of the constraint.
>> + * @t: wakeup latency constraint (us). -1 removes the existing constraint.
>> + *
>> + * Query the powerdomain of @oh to set/release the wake-up constraint.
>> + * @oh is used to determine which power domain to set a constraint on.
>> + * @req_oh is used to record the requester for later update or removal
>> + * of a constraint.
>> + *
>> + * Returns -EINVAL if @oh or @req_oh have no power domain, or the return
>> + * code from the pwrdm function (pwrdm_wakeuplat_set/release_constraint)
>> + * of the powerdomain assocated with @oh.
>> + */
>> +int omap_hwmod_set_max_dev_wakeup_lat(struct omap_hwmod *req_oh,
>> +                                   struct omap_hwmod *oh, long t)
>> +{
>> +     struct device *req_dev;
>> +     struct platform_device *req_pdev;
>> +     struct powerdomain *pwrdm;
>> +
>> +     pwrdm = omap_hwmod_get_pwrdm(oh);
>> +
>> +     /* Catch devices with undefined powerdomains */
>> +     if (!PTR_ERR(pwrdm)) {
>> +             pr_err("omap_hwmod: Error: could not find parent "
>> +                     "powerdomain for %s\n", oh->name);
>> +             return -EINVAL;
>> +     }
>> +
>> +     req_pdev = &(req_oh->od->pdev);
>> +     if (!PTR_ERR(req_pdev)) {
>> +             pr_err("omap_hwmod: Error: pdev not found for oh %s\n",
>> +                    oh->name);
>> +             return -EINVAL;
>> +     }
>> +
>> +     req_dev = &(req_pdev->dev);
>> +     if (!PTR_ERR(req_dev)) {
>> +             pr_err("omap_hwmod: Error: device not found for oh %s\n",
>> +                    oh->name);
>> +             return -EINVAL;
>> +     }
>> +
>> +     /* Call set/release_constraint for the given pwrdm */
>> +     if (t == -1) {
>> +             pr_debug("omap_hwmod: remove max device latency constraint: "
>> +                      "oh %s, pwrdm %s, req by oh %s\n",
>> +                      oh->name, pwrdm->name, req_oh->name);
>> +     } else {
>> +             pr_debug("omap_hwmod: add max device latency constraint: "
>> +                      "oh %s, t = %ld usec, pwrdm %s, req by oh %s\n",
>> +                      oh->name, t, pwrdm->name, req_oh->name);
>> +     }
>> +
>> +     return pwrdm_wakeuplat_set_constraint(pwrdm, req_dev, t);
>> +}
>> +
>> +/**
>>   * omap_hwmod_get_context_loss_count - get lost context count
>>   * @oh: struct omap_hwmod *
>>   *
>> - * Query the powerdomain of of @oh to get the context loss
>> + * Query the powerdomain of @oh to get the context loss
>>   * count for this device.
>>   *
>>   * Returns the context loss count of the powerdomain assocated with @oh
>> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
>> index eaed0df..6fb4741 100644
>> --- a/arch/arm/mach-omap2/powerdomain.c
>> +++ b/arch/arm/mach-omap2/powerdomain.c
>> @@ -19,6 +19,8 @@
>>  #include <linux/list.h>
>>  #include <linux/errno.h>
>>  #include <linux/string.h>
>> +#include <linux/slab.h>
>> +
>>  #include "cm2xxx_3xxx.h"
>>  #include "prcm44xx.h"
>>  #include "cm44xx.h"
>> @@ -103,6 +105,13 @@ static int _pwrdm_register(struct powerdomain *pwrdm)
>>       pwrdm->state = pwrdm_read_pwrst(pwrdm);
>>       pwrdm->state_counter[pwrdm->state] = 1;
>>
>> +     /* Initialize priority ordered list for wakeup latency constraint */
>> +     spin_lock_init(&pwrdm->wakeuplat_lock);
>> +     plist_head_init(&pwrdm->wakeuplat_dev_list, &pwrdm->wakeuplat_lock);
>> +
>> +     /* res_mutex protects res_list add and del ops */
>> +     mutex_init(&pwrdm->wakeuplat_mutex);
>> +
>>       pr_debug("powerdomain: registered %s\n", pwrdm->name);
>>
>>       return 0;
>> @@ -176,6 +185,74 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
>>       return 0;
>>  }
>>
>> +/**
>> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
>> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
>> + *
>> + * Finds the minimum allowed wake-up latency value from all entries
>> + * in the list and the power domain power state needing the constraint.
>> + * Programs a new target state if it is different from current power state.
>> + *
>> + * Only OMAP3xxx is supported for now
>> + *
>> + * Returns 0 upon success.
>> + */
>> +static int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm)
>> +{
>> +     struct plist_node *node;
>> +     int ret = 0, new_state;
>> +     long min_latency = -1;
>> +
>> +     /* Find the strongest constraint from the plist */
>> +     if (!plist_head_empty(&pwrdm->wakeuplat_dev_list)) {
>> +             node = plist_first(&pwrdm->wakeuplat_dev_list);
>> +             min_latency = node->prio;
>> +     }
>> +
>> +     /* Find power state with wakeup latency < minimum constraint. */
>> +     for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
>> +             if (min_latency == -1 ||
>> +                 pwrdm->wakeup_lat[new_state] <= min_latency)
>> +                     break;
>> +     }
>> +
>> +     switch (new_state) {
>> +     case PWRDM_FUNC_PWRST_OFF:
>> +             new_state = PWRDM_POWER_OFF;
>> +             break;
>> +     case PWRDM_FUNC_PWRST_OSWR:
>> +             if (cpu_is_omap34xx())
>> +                     pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
>
> cpu_is_* checks here aren't right.
>
> You should use SoC specific function pointers as are done for many of the
> other powerdomain calls after Rajendra's splitup series.
The cpu_is_* tests are not related to the SoC specific function
pointers but rather to the comment in the function description 'Only
OMAP3xxx is supported for now'.
In fact the function that are conditionally called
(pwrdm_set_logic_retst and omap_set_pwrdm_state) are correctly using
the SoC specific pointers.

Is this test needed? If so is it the correct way to do it?

>
>> +             new_state = PWRDM_POWER_RET;
>> +             break;
>> +     case PWRDM_FUNC_PWRST_CSWR:
>> +             if (cpu_is_omap34xx())
>> +                     pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
>> +             new_state = PWRDM_POWER_RET;
>> +             break;
>> +     case PWRDM_FUNC_PWRST_ON:
>> +             new_state = PWRDM_POWER_ON;
>> +             break;
>> +     default:
>> +             pr_warn("powerdomain: requested latency constraint not "
>> +                     "supported %s set to ON state\n", pwrdm->name);
>> +             new_state = PWRDM_POWER_ON;
>> +             break;
>> +     }
>> +
>> +     if (pwrdm_read_pwrst(pwrdm) != new_state) {
>> +             if (cpu_is_omap34xx())
>> +                     ret = omap_set_pwrdm_state(pwrdm, new_state);
>> +     }
>> +
>> +     pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
>> +              "min_latency=%ld, set_state=%d\n", pwrdm->name,
>> +              pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
>> +              pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
>> +
>> +     return ret;
>> +}
>> +
>
> [...]
>
>> diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
>> index e1bec56..4f7e44d 100644
>> --- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
>> +++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
>> @@ -52,6 +52,12 @@ static struct powerdomain iva2_pwrdm = {
>>               [2] = PWRSTS_OFF_ON,
>>               [3] = PWRDM_POWER_ON,
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 1100,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 350,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain mpu_3xxx_pwrdm = {
>> @@ -68,6 +74,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRSTS_OFF_ON,
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 95,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 45,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  /*
>> @@ -98,6 +110,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
>>               [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>>               [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 100,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 60,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain core_3xxx_es3_1_pwrdm = {
>> @@ -121,6 +139,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
>>               [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>>               [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 100,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 60,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain dss_pwrdm = {
>> @@ -136,6 +160,12 @@ static struct powerdomain dss_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 70,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 20,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  /*
>> @@ -157,6 +187,12 @@ static struct powerdomain sgx_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 1000,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain cam_pwrdm = {
>> @@ -172,6 +208,12 @@ static struct powerdomain cam_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 850,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 35,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain per_pwrdm = {
>> @@ -187,6 +229,12 @@ static struct powerdomain per_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 200,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 110,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain emu_pwrdm = {
>> @@ -201,6 +249,12 @@ static struct powerdomain neon_pwrdm = {
>>       .omap_chip        = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
>>       .pwrsts           = PWRSTS_OFF_RET_ON,
>>       .pwrsts_logic_ret = PWRDM_POWER_RET,
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 200,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 35,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain usbhost_pwrdm = {
>> @@ -223,6 +277,12 @@ static struct powerdomain usbhost_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 800,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 150,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>
> A summary about where the latency numbers for each powerdomain come from
> would be useful.
Ok

>
> [...]
>
>> @@ -87,64 +60,86 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>>       return 0;
>>  }
>>
>> +/*
>> + * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
>> + * constraints
>> + */
>>  int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
>>                                  long t)
>>  {
>> +     struct platform_device *pdev, *req_pdev;
>> +     int ret = 0;
>> +
>>       if (!req_dev || !dev || t < -1) {
>>               WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>>               return -EINVAL;
>> +     }
>> +
>> +     /* Look for the platform devices */
>> +     pdev = to_platform_device(dev);
>> +     req_pdev = to_platform_device(req_dev);
>> +
>> +     /* Try to catch non platform devices. */
>> +     if ((pdev->name == NULL) || (req_pdev->name == NULL)) {
>> +             pr_err("OMAP-PM set_wakeup_lat: Error: platform devices "
>> +                    "not valid\n");
>> +             return -EINVAL;
>> +     } else {
>> +             /* Call the omap_device API */
>> +             ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
>> +     }
>
> I don't think a NULL name check is the right sanity check here.  WHat
> you really need to know is whether the target device is an omap_device.
> The requesting device can be anything (I think.)
>
> Here's a simpler check:
>
>        if (pdev->dev->parent == &omap_device_parent)
>                ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
>        else
>                ...
Ok I will use this test. Note: the dev parameter is already checked
for NULL above.

Also I think the requester parameter needs to keep the device* type
across all layers. In any case only this type is used by the low level
code (in powerdomain.c). This allows for any device (i.e. that does
not necessarily have an associated omap_device) to request
constraints.
What do you think?

>
>
>> +     return ret;
>> +}
>
> Kevin
>

Thanks for reviewing the code.

Jean
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Re: [PATCH 2/2] OMAP: PM: implement devices wakeup latency constraints APIs

[Kevin Hilman]

Jean Pihet <jean.pihet@newoldbits.com> writes:

> On Tue, Mar 8, 2011 at 3:15 AM, Kevin Hilman <khilman@ti.com> wrote:
>> Jean Pihet <jean.pihet@newoldbits.com> writes:
>>
>>> Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
>>> creating similar APIs at the omap_device and omap_hwmod levels. The
>>> omap_hwmod level call is the layer with access to the powerdomain
>>> core, so it is the place where the powerdomain is queried to set and
>>> release the constraints.
>>>
>>> NOTE: only works for devices which have been converted to use
>>>       omap_device/omap_hwmod.
>>>
>>> Longer term, we could possibly remove this API from the OMAP PM layer,
>>> and instead directly use the device level API.
>>>
>>> The power domains get the next power state programmed directly in
>>> the registers via pwrdm_wakeuplat_update_pwrst.
>>>
>>> Note about PM QOS: the MPU and CORE power domains get the next power
>>> state via cpuidle, which get the strongest wake-up latency constraint
>>> by querying PM QOS. The usage of PM QOS is temporary, until a generic
>>> solution is in place.
>>>
>>> Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
>>> and PM QOS frameworks.
>>
>> I haven't got to a detailed review of this code yet, but did do some
>> experiements and have some general comments on the code/design to get
>> started.
>>
>> Also, I had a problem doing a real dumb test until I figured out the
>> problem with the init sequence.  I tried setting a constraint in the
>> device init code for UART (mach-omap2/serial.c:omap_serial_init_port()),
>> and then I realized that that runs before
>> mach-omap2/pm34xx.c:pwrdms_setup() which also calls
>> omap_set_pwrdm_state() for each powerdomain to initialize.
>
> Do we need to change the behavior at init?
>

I think so.  

At a minimum, it should be documented somewhere that the constraints API
cannot be used before pwrdms_setup().  But since that happens much later
in the boot process than device init code, that might be too strict.

>> Also, for debug purposes, it might be useful to have a per-device sysfs
>> interface to setting this wakeup latency constraint.  Something like
>>
>>   /sys/devices/platform/omap/.../power/wakeup_latency
> I do not see this as a debug interface but rather an API to the user space.
> If that is the case there are some issues to deal with, cf. below.

By debug, I was thinking under '#ifdef CONFIG_PM_DEBUG'.  Even if you
did this as a separate patch that we did not try to get upstream, it
would be extremely valuable for testing this framework.

>> I'm not sure exactly what to set the requesting device to though.
> And also, how to track the requesters? PM QOS is using a /dev node
> that must be kept open as long as the constraints remains valid.

A dummy device could be created for all sysfs requesters since you would
want subsequent writes to override  previous ones.

>> As far as implementation goes, you've so far implemented only wakeup
>> latencies, but not througput.  When you implement throughput you will
>> have to duplicate large parts of this code and data structures for
>> throughput, and if ever add some other constraint (frequency, voltage)
>> it would need to be duplicated again.
>>
>> Maybe now is the time to consider an interface to add a generic
>> per-device constraint, with a type (latency, throughput, etc.), or
>> "class" as it's called in PM QoS.  For now the type/class does not need
>> to be exposed externally, but will make implementing new constraint
>> types much easer.
> Ok that makes sense.
> In the current patch the constraints plist is stored inside the
> powerdomain structure. This does not apply to throughput, frequency
> and voltage constraints.
> Should the list constraint be managed in the OMAP PM layer instead of
> in the power domain code? If so where to store the constraints?

I was thinking at the omap_device layer, where there would be a
constraint plist managed for each class of constraint.

>> Some other comments below...
>>
>>> Signed-off-by: Jean Pihet <j-pihet@ti.com>
>>> Cc: Vibhore Vardhan <vvardhan@ti.com>
>>> ---
>>> Based on khilman's pm-core branch
>>>
>>>  arch/arm/mach-omap2/omap_hwmod.c              |   62 ++++++++-
>>>  arch/arm/mach-omap2/powerdomain.c             |  197 +++++++++++++++++++++++++
>>>  arch/arm/mach-omap2/powerdomain.h             |   39 +++++-
>>>  arch/arm/mach-omap2/powerdomains3xxx_data.c   |   60 ++++++++
>>>  arch/arm/plat-omap/include/plat/omap_device.h |    2 +
>>>  arch/arm/plat-omap/include/plat/omap_hwmod.h  |    2 +
>>>  arch/arm/plat-omap/omap-pm-constraints.c      |  121 +++++++--------
>>>  arch/arm/plat-omap/omap_device.c              |   28 ++++
>>>  8 files changed, 446 insertions(+), 65 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
>>> index 028efda..bad8248 100644
>>> --- a/arch/arm/mach-omap2/omap_hwmod.c
>>> +++ b/arch/arm/mach-omap2/omap_hwmod.c
>>> @@ -142,6 +142,7 @@
>>>  #include "powerdomain.h"
>>>  #include <plat/clock.h>
>>>  #include <plat/omap_hwmod.h>
>>> +#include <plat/omap_device.h>
>>>  #include <plat/prcm.h>
>>>
>>>  #include "cm2xxx_3xxx.h"
>>> @@ -2267,10 +2268,69 @@ ohsps_unlock:
>>>  }
>>>
>>>  /**
>>> + * omap_hwmod_set_max_dev_wakeup_lat - set a device wake-up constraint
>>> + * @oh: the device of @oh to set a constraint on.
>>> + * @req_oh: the device of @req_oh is the requester of the constraint.
>>> + * @t: wakeup latency constraint (us). -1 removes the existing constraint.
>>> + *
>>> + * Query the powerdomain of @oh to set/release the wake-up constraint.
>>> + * @oh is used to determine which power domain to set a constraint on.
>>> + * @req_oh is used to record the requester for later update or removal
>>> + * of a constraint.
>>> + *
>>> + * Returns -EINVAL if @oh or @req_oh have no power domain, or the return
>>> + * code from the pwrdm function (pwrdm_wakeuplat_set/release_constraint)
>>> + * of the powerdomain assocated with @oh.
>>> + */
>>> +int omap_hwmod_set_max_dev_wakeup_lat(struct omap_hwmod *req_oh,
>>> +                                   struct omap_hwmod *oh, long t)
>>> +{
>>> +     struct device *req_dev;
>>> +     struct platform_device *req_pdev;
>>> +     struct powerdomain *pwrdm;
>>> +
>>> +     pwrdm = omap_hwmod_get_pwrdm(oh);
>>> +
>>> +     /* Catch devices with undefined powerdomains */
>>> +     if (!PTR_ERR(pwrdm)) {
>>> +             pr_err("omap_hwmod: Error: could not find parent "
>>> +                     "powerdomain for %s\n", oh->name);
>>> +             return -EINVAL;
>>> +     }
>>> +
>>> +     req_pdev = &(req_oh->od->pdev);
>>> +     if (!PTR_ERR(req_pdev)) {
>>> +             pr_err("omap_hwmod: Error: pdev not found for oh %s\n",
>>> +                    oh->name);
>>> +             return -EINVAL;
>>> +     }
>>> +
>>> +     req_dev = &(req_pdev->dev);
>>> +     if (!PTR_ERR(req_dev)) {
>>> +             pr_err("omap_hwmod: Error: device not found for oh %s\n",
>>> +                    oh->name);
>>> +             return -EINVAL;
>>> +     }
>>> +
>>> +     /* Call set/release_constraint for the given pwrdm */
>>> +     if (t == -1) {
>>> +             pr_debug("omap_hwmod: remove max device latency constraint: "
>>> +                      "oh %s, pwrdm %s, req by oh %s\n",
>>> +                      oh->name, pwrdm->name, req_oh->name);
>>> +     } else {
>>> +             pr_debug("omap_hwmod: add max device latency constraint: "
>>> +                      "oh %s, t = %ld usec, pwrdm %s, req by oh %s\n",
>>> +                      oh->name, t, pwrdm->name, req_oh->name);
>>> +     }
>>> +
>>> +     return pwrdm_wakeuplat_set_constraint(pwrdm, req_dev, t);
>>> +}
>>> +
>>> +/**
>>>   * omap_hwmod_get_context_loss_count - get lost context count
>>>   * @oh: struct omap_hwmod *
>>>   *
>>> - * Query the powerdomain of of @oh to get the context loss
>>> + * Query the powerdomain of @oh to get the context loss
>>>   * count for this device.
>>>   *
>>>   * Returns the context loss count of the powerdomain assocated with @oh
>>> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
>>> index eaed0df..6fb4741 100644
>>> --- a/arch/arm/mach-omap2/powerdomain.c
>>> +++ b/arch/arm/mach-omap2/powerdomain.c
>>> @@ -19,6 +19,8 @@
>>>  #include <linux/list.h>
>>>  #include <linux/errno.h>
>>>  #include <linux/string.h>
>>> +#include <linux/slab.h>
>>> +
>>>  #include "cm2xxx_3xxx.h"
>>>  #include "prcm44xx.h"
>>>  #include "cm44xx.h"
>>> @@ -103,6 +105,13 @@ static int _pwrdm_register(struct powerdomain *pwrdm)
>>>       pwrdm->state = pwrdm_read_pwrst(pwrdm);
>>>       pwrdm->state_counter[pwrdm->state] = 1;
>>>
>>> +     /* Initialize priority ordered list for wakeup latency constraint */
>>> +     spin_lock_init(&pwrdm->wakeuplat_lock);
>>> +     plist_head_init(&pwrdm->wakeuplat_dev_list, &pwrdm->wakeuplat_lock);
>>> +
>>> +     /* res_mutex protects res_list add and del ops */
>>> +     mutex_init(&pwrdm->wakeuplat_mutex);
>>> +
>>>       pr_debug("powerdomain: registered %s\n", pwrdm->name);
>>>
>>>       return 0;
>>> @@ -176,6 +185,74 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
>>>       return 0;
>>>  }
>>>
>>> +/**
>>> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
>>> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
>>> + *
>>> + * Finds the minimum allowed wake-up latency value from all entries
>>> + * in the list and the power domain power state needing the constraint.
>>> + * Programs a new target state if it is different from current power state.
>>> + *
>>> + * Only OMAP3xxx is supported for now
>>> + *
>>> + * Returns 0 upon success.
>>> + */
>>> +static int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm)
>>> +{
>>> +     struct plist_node *node;
>>> +     int ret = 0, new_state;
>>> +     long min_latency = -1;
>>> +
>>> +     /* Find the strongest constraint from the plist */
>>> +     if (!plist_head_empty(&pwrdm->wakeuplat_dev_list)) {
>>> +             node = plist_first(&pwrdm->wakeuplat_dev_list);
>>> +             min_latency = node->prio;
>>> +     }
>>> +
>>> +     /* Find power state with wakeup latency < minimum constraint. */
>>> +     for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
>>> +             if (min_latency == -1 ||
>>> +                 pwrdm->wakeup_lat[new_state] <= min_latency)
>>> +                     break;
>>> +     }
>>> +
>>> +     switch (new_state) {
>>> +     case PWRDM_FUNC_PWRST_OFF:
>>> +             new_state = PWRDM_POWER_OFF;
>>> +             break;
>>> +     case PWRDM_FUNC_PWRST_OSWR:
>>> +             if (cpu_is_omap34xx())
>>> +                     pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
>>
>> cpu_is_* checks here aren't right.
>>
>> You should use SoC specific function pointers as are done for many of the
>> other powerdomain calls after Rajendra's splitup series.
> The cpu_is_* tests are not related to the SoC specific function
> pointers but rather to the comment in the function description 'Only
> OMAP3xxx is supported for now'.
> In fact the function that are conditionally called
> (pwrdm_set_logic_retst and omap_set_pwrdm_state) are correctly using
> the SoC specific pointers.
>
> Is this test needed? If so is it the correct way to do it?

Right, I think you can just drop the cpu_is_* checks here since as you
pointed out, the called functions already handle SoC specifics.

>>
>>> +             new_state = PWRDM_POWER_RET;
>>> +             break;
>>> +     case PWRDM_FUNC_PWRST_CSWR:
>>> +             if (cpu_is_omap34xx())
>>> +                     pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
>>> +             new_state = PWRDM_POWER_RET;
>>> +             break;
>>> +     case PWRDM_FUNC_PWRST_ON:
>>> +             new_state = PWRDM_POWER_ON;
>>> +             break;
>>> +     default:
>>> +             pr_warn("powerdomain: requested latency constraint not "
>>> +                     "supported %s set to ON state\n", pwrdm->name);
>>> +             new_state = PWRDM_POWER_ON;
>>> +             break;
>>> +     }
>>> +
>>> +     if (pwrdm_read_pwrst(pwrdm) != new_state) {
>>> +             if (cpu_is_omap34xx())
>>> +                     ret = omap_set_pwrdm_state(pwrdm, new_state);
>>> +     }
>>> +
>>> +     pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
>>> +              "min_latency=%ld, set_state=%d\n", pwrdm->name,
>>> +              pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
>>> +              pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
>>> +
>>> +     return ret;
>>> +}
>>> +
>>
>> [...]
>>
>>> diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
>>> index e1bec56..4f7e44d 100644
>>> --- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
>>> +++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
>>> @@ -52,6 +52,12 @@ static struct powerdomain iva2_pwrdm = {
>>>               [2] = PWRSTS_OFF_ON,
>>>               [3] = PWRDM_POWER_ON,
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 1100,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 350,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain mpu_3xxx_pwrdm = {
>>> @@ -68,6 +74,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
>>>       .pwrsts_mem_on    = {
>>>               [0] = PWRSTS_OFF_ON,
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 95,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 45,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  /*
>>> @@ -98,6 +110,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
>>>               [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>>>               [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 100,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 60,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain core_3xxx_es3_1_pwrdm = {
>>> @@ -121,6 +139,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
>>>               [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>>>               [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 100,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 60,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain dss_pwrdm = {
>>> @@ -136,6 +160,12 @@ static struct powerdomain dss_pwrdm = {
>>>       .pwrsts_mem_on    = {
>>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 70,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 20,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  /*
>>> @@ -157,6 +187,12 @@ static struct powerdomain sgx_pwrdm = {
>>>       .pwrsts_mem_on    = {
>>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 1000,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain cam_pwrdm = {
>>> @@ -172,6 +208,12 @@ static struct powerdomain cam_pwrdm = {
>>>       .pwrsts_mem_on    = {
>>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 850,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 35,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain per_pwrdm = {
>>> @@ -187,6 +229,12 @@ static struct powerdomain per_pwrdm = {
>>>       .pwrsts_mem_on    = {
>>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 200,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 110,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain emu_pwrdm = {
>>> @@ -201,6 +249,12 @@ static struct powerdomain neon_pwrdm = {
>>>       .omap_chip        = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
>>>       .pwrsts           = PWRSTS_OFF_RET_ON,
>>>       .pwrsts_logic_ret = PWRDM_POWER_RET,
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 200,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 35,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>>
>>>  static struct powerdomain usbhost_pwrdm = {
>>> @@ -223,6 +277,12 @@ static struct powerdomain usbhost_pwrdm = {
>>>       .pwrsts_mem_on    = {
>>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>>       },
>>> +     .wakeup_lat = {
>>> +             [PWRDM_FUNC_PWRST_OFF] = 800,
>>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>>> +             [PWRDM_FUNC_PWRST_CSWR] = 150,
>>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>>> +     },
>>>  };
>>
>> A summary about where the latency numbers for each powerdomain come from
>> would be useful.
> Ok
>
>>
>> [...]
>>
>>> @@ -87,64 +60,86 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>>>       return 0;
>>>  }
>>>
>>> +/*
>>> + * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
>>> + * constraints
>>> + */
>>>  int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
>>>                                  long t)
>>>  {
>>> +     struct platform_device *pdev, *req_pdev;
>>> +     int ret = 0;
>>> +
>>>       if (!req_dev || !dev || t < -1) {
>>>               WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>>>               return -EINVAL;
>>> +     }
>>> +
>>> +     /* Look for the platform devices */
>>> +     pdev = to_platform_device(dev);
>>> +     req_pdev = to_platform_device(req_dev);
>>> +
>>> +     /* Try to catch non platform devices. */
>>> +     if ((pdev->name == NULL) || (req_pdev->name == NULL)) {
>>> +             pr_err("OMAP-PM set_wakeup_lat: Error: platform devices "
>>> +                    "not valid\n");
>>> +             return -EINVAL;
>>> +     } else {
>>> +             /* Call the omap_device API */
>>> +             ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
>>> +     }
>>
>> I don't think a NULL name check is the right sanity check here.  WHat
>> you really need to know is whether the target device is an omap_device.
>> The requesting device can be anything (I think.)
>>
>> Here's a simpler check:
>>
>>        if (pdev->dev->parent == &omap_device_parent)
>>                ret = omap_device_set_max_dev_wakeup_lat(req_pdev, pdev, t);
>>        else
>>                ...
> Ok I will use this test. Note: the dev parameter is already checked
> for NULL above.
>
> Also I think the requester parameter needs to keep the device* type
> across all layers. In any case only this type is used by the low level
> code (in powerdomain.c). This allows for any device (i.e. that does
> not necessarily have an associated omap_device) to request
> constraints.
> What do you think?

I agree that the only the target device needs to be an omap_device, the
requester can be any device.

Kevin
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[PATCH 2/2] OMAP: PM: implement devices constraints APIs

[Jean Pihet]

Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
creating a unified API which calls omap_device_set_dev_constraint
for all classes of constraints (devices wake-up latency, devices
throughput...).
The implementation of the constraints framework is at the omap_device
level: management and storage of the constraints, dispatching of the
constraints to the appropriate low level layers.

NOTE: only works for devices which have been converted to use
      omap_device/omap_hwmod.

Longer term, we could possibly remove this API from the OMAP PM layer,
and instead directly use the device level API.

For the devices wake-up latency constraints, the power domains get
the next power state programmed directly in the registers via
pwrdm_wakeuplat_update_pwrst.

Note about PM QOS: the MPU and CORE power domains get the next power
state via cpuidle, which get the strongest wake-up latency constraint
by querying PM QOS. The usage of PM QOS is temporary, until a generic
solution is in place.

Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
and PM QOS frameworks.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Cc: Vibhore Vardhan <vvardhan@ti.com>
---
 arch/arm/mach-omap2/omap_hwmod.c              |   29 ++++-
 arch/arm/mach-omap2/powerdomain.c             |   99 +++++++++++++
 arch/arm/mach-omap2/powerdomain.h             |   24 +++-
 arch/arm/mach-omap2/powerdomains3xxx_data.c   |   63 +++++++++
 arch/arm/plat-omap/include/plat/omap-pm.h     |    6 +-
 arch/arm/plat-omap/include/plat/omap_device.h |   14 ++
 arch/arm/plat-omap/include/plat/omap_hwmod.h  |    1 +
 arch/arm/plat-omap/omap-pm-constraints.c      |  161 ++++++++++------------
 arch/arm/plat-omap/omap-pm-noop.c             |    2 +-
 arch/arm/plat-omap/omap_device.c              |  187 +++++++++++++++++++++++++
 10 files changed, 493 insertions(+), 93 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index cf8cc9b..8caf2c5 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -142,6 +142,7 @@
 #include "powerdomain.h"
 #include <plat/clock.h>
 #include <plat/omap_hwmod.h>
+#include <plat/omap_device.h>
 #include <plat/prcm.h>
 
 #include "cm2xxx_3xxx.h"
@@ -2277,11 +2278,37 @@ ohsps_unlock:
 	return ret;
 }
 
+/*
+ * omap_hwmod_update_power_state - Update the power domain power state of
+ * @oh
+ *
+ * @oh: struct omap_hwmod* to which the requesting device belongs to.
+ * @min_latency: the allowed wake-up latency for the power domain of @oh.
+ *
+ * Finds the power domain next power state that fulfills the constraint.
+ * Applies the constraint to the power domain by calling
+ * pwrdm_wakeuplat_update_pwrst.
+ *
+ * Returns 0 upon success.
+ */
+int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency)
+{
+	struct powerdomain *pwrdm = omap_hwmod_get_pwrdm(oh);
+
+	if (!PTR_ERR(pwrdm)) {
+		pr_err("omap_hwmod: Error: could not find parent "
+			"powerdomain for %s\n", oh->name);
+		return -EINVAL;
+	}
+
+	return pwrdm_wakeuplat_update_pwrst(pwrdm, min_latency);
+}
+
 /**
  * omap_hwmod_get_context_loss_count - get lost context count
  * @oh: struct omap_hwmod *
  *
- * Query the powerdomain of of @oh to get the context loss
+ * Query the powerdomain of @oh to get the context loss
  * count for this device.
  *
  * Returns the context loss count of the powerdomain assocated with @oh
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index eaed0df..496f245 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -19,6 +19,7 @@
 #include <linux/list.h>
 #include <linux/errno.h>
 #include <linux/string.h>
+
 #include "cm2xxx_3xxx.h"
 #include "prcm44xx.h"
 #include "cm44xx.h"
@@ -176,6 +177,104 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
 	return 0;
 }
 
+/*
+ * Test if the current powerdomain is MPU or CORE
+ *
+ * This function is only used by pwrdm_wakeuplat_update_pwrst
+ * which applies the MPU and CORE power domains constraints using PM QOS.
+ *
+ * This will disappear when all power domains will be controlled directly
+ * from the wake-up latency constraints framework
+ */
+static inline int is_pwrdm_mpu_or_core(struct powerdomain *pwrdm)
+{
+	if ((strncmp(pwrdm->name, "mpu_pwrdm", 9) == 0) ||
+	    (strncmp(pwrdm->name, "core_pwrdm", 10) == 0))
+		return 1;
+	else
+		return 0;
+}
+
+/**
+ * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
+ * @pwrdm: struct powerdomain * to which requesting device belongs to.
+ * @min_latency: the allowed wake-up latency for the given power domain.
+ *
+ * Finds the power domain next power state that fulfills the constraint.
+ * Programs a new target state if it is different from current power state.
+ *
+ * Returns 0 upon success.
+ */
+int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency)
+{
+	int ret = 0, new_state = 0;
+
+	if (!pwrdm) {
+		WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	}
+
+	/*
+	 * Apply constraints to MPU and CORE via the PM QOS API.
+	 * Every power domain struct has a pm_qos_request_list field
+	 */
+	if (is_pwrdm_mpu_or_core(pwrdm)) {
+		if (pm_qos_request_active(&(pwrdm->pm_qos_request)))
+			pm_qos_remove_request(&(pwrdm->pm_qos_request));
+
+		if (min_latency >= 0)
+			pm_qos_add_request(&(pwrdm->pm_qos_request),
+					   PM_QOS_CPU_DMA_LATENCY,
+					   min_latency);
+		return 0;
+	}
+
+	/*
+	 * Apply constraints to pwrdm other than MPU and CORE by programming
+	 * the pwrdm next power state.
+	 */
+
+	/* Find power state with wakeup latency < minimum constraint */
+	for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
+		if (min_latency == -1 ||
+		    pwrdm->wakeup_lat[new_state] <= min_latency)
+			break;
+	}
+
+	switch (new_state) {
+	case PWRDM_FUNC_PWRST_OFF:
+		new_state = PWRDM_POWER_OFF;
+		break;
+	case PWRDM_FUNC_PWRST_OSWR:
+		pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
+		new_state = PWRDM_POWER_RET;
+		break;
+	case PWRDM_FUNC_PWRST_CSWR:
+		pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
+		new_state = PWRDM_POWER_RET;
+		break;
+	case PWRDM_FUNC_PWRST_ON:
+		new_state = PWRDM_POWER_ON;
+		break;
+	default:
+		pr_warn("powerdomain: requested latency constraint not "
+			"supported %s set to ON state\n", pwrdm->name);
+		new_state = PWRDM_POWER_ON;
+		break;
+	}
+
+	if (pwrdm_read_pwrst(pwrdm) != new_state) {
+		ret = omap_set_pwrdm_state(pwrdm, new_state);
+	}
+
+	pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
+		 "min_latency=%ld, set_state=%d\n", pwrdm->name,
+		 pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
+		 pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
+
+	return ret;
+}
+
 /* Public functions */
 
 /**
diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
index 0b7a357..c796469 100644
--- a/arch/arm/mach-omap2/powerdomain.h
+++ b/arch/arm/mach-omap2/powerdomain.h
@@ -19,7 +19,10 @@
 
 #include <linux/types.h>
 #include <linux/list.h>
-
+#include <linux/plist.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/pm_qos_params.h>
 #include <linux/atomic.h>
 
 #include <plat/cpu.h>
@@ -46,6 +49,15 @@
 
 #define PWRSTS_OFF_RET_ON	(PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))
 
+/* Powerdomain functional power states */
+#define PWRDM_FUNC_PWRST_OFF	0x0
+#define PWRDM_FUNC_PWRST_OSWR	0x1
+#define PWRDM_FUNC_PWRST_CSWR	0x2
+#define PWRDM_FUNC_PWRST_ON	0x3
+
+#define PWRDM_MAX_FUNC_PWRSTS	4
+
+#define UNSUP_STATE		-1
 
 /* Powerdomain flags */
 #define PWRDM_HAS_HDWR_SAR	(1 << 0) /* hardware save-and-restore support */
@@ -96,7 +108,11 @@ struct powerdomain;
  * @state_counter:
  * @timer:
  * @state_timer:
- *
+ * @wakeup_lat: wakeup latencies for possible powerdomain power states
+ * Note about the wakeup latencies ordering: the values must be sorted
+ *  in decremental order
+ * @pm_qos_request: PM QOS handle, only used to control the MPU and CORE power
+ *  domains states; to be removed when a generic solution is in place.
  * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
  */
 struct powerdomain {
@@ -121,6 +137,8 @@ struct powerdomain {
 	s64 timer;
 	s64 state_timer[PWRDM_MAX_PWRSTS];
 #endif
+	const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
+	struct pm_qos_request_list pm_qos_request;
 };
 
 /**
@@ -210,6 +228,8 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
 int pwrdm_pre_transition(void);
 int pwrdm_post_transition(void);
 int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
+
+int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency);
 u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
 
 extern void omap2xxx_powerdomains_init(void);
diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
index e1bec56..64973d1 100644
--- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
+++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
@@ -31,6 +31,9 @@
 
 /*
  * Powerdomains
+ *
+ * The wakeup_lat values are derived from measurements on
+ * the actual target.
  */
 
 static struct powerdomain iva2_pwrdm = {
@@ -52,6 +55,12 @@ static struct powerdomain iva2_pwrdm = {
 		[2] = PWRSTS_OFF_ON,
 		[3] = PWRDM_POWER_ON,
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 1100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 350,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain mpu_3xxx_pwrdm = {
@@ -68,6 +77,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRSTS_OFF_ON,
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 95,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 45,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 /*
@@ -98,6 +113,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
 		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
 		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 60,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain core_3xxx_es3_1_pwrdm = {
@@ -121,6 +142,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
 		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
 		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 100,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 60,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain dss_pwrdm = {
@@ -136,6 +163,12 @@ static struct powerdomain dss_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 70,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 20,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 /*
@@ -157,6 +190,12 @@ static struct powerdomain sgx_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 1000,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain cam_pwrdm = {
@@ -172,6 +211,12 @@ static struct powerdomain cam_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 850,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 35,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain per_pwrdm = {
@@ -187,6 +232,12 @@ static struct powerdomain per_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 200,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 110,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain emu_pwrdm = {
@@ -201,6 +252,12 @@ static struct powerdomain neon_pwrdm = {
 	.omap_chip	  = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
 	.pwrsts		  = PWRSTS_OFF_RET_ON,
 	.pwrsts_logic_ret = PWRDM_POWER_RET,
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 200,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 35,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain usbhost_pwrdm = {
@@ -223,6 +280,12 @@ static struct powerdomain usbhost_pwrdm = {
 	.pwrsts_mem_on	  = {
 		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
 	},
+	.wakeup_lat = {
+		[PWRDM_FUNC_PWRST_OFF] = 800,
+		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
+		[PWRDM_FUNC_PWRST_CSWR] = 150,
+		[PWRDM_FUNC_PWRST_ON] = 0,
+	},
 };
 
 static struct powerdomain dpll1_pwrdm = {
diff --git a/arch/arm/plat-omap/include/plat/omap-pm.h b/arch/arm/plat-omap/include/plat/omap-pm.h
index c0a7520..16f9e84 100644
--- a/arch/arm/plat-omap/include/plat/omap-pm.h
+++ b/arch/arm/plat-omap/include/plat/omap-pm.h
@@ -70,6 +70,10 @@ void omap_pm_if_exit(void);
  * Device-driver-originated constraints (via board-*.c files, platform_data)
  */
 
+enum omap_pm_constraint_class {
+	OMAP_PM_CONSTRAINT_WKUP_LAT,
+	OMAP_PM_CONSTRAINT_THROUGHPUT
+};
 
 /**
  * omap_pm_set_max_mpu_wakeup_lat - set the maximum MPU wakeup latency
@@ -137,7 +141,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t);
  * Returns -EINVAL for an invalid argument, -ERANGE if the constraint
  * is not satisfiable, or 0 upon success.
  */
-int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r);
+int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r);
 
 
 /**
diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
index e4c349f..d4766c4 100644
--- a/arch/arm/plat-omap/include/plat/omap_device.h
+++ b/arch/arm/plat-omap/include/plat/omap_device.h
@@ -32,9 +32,11 @@
 #define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
 
 #include <linux/kernel.h>
+#include <linux/plist.h>
 #include <linux/platform_device.h>
 
 #include <plat/omap_hwmod.h>
+#include <plat/omap-pm.h>
 
 extern struct device omap_device_parent;
 
@@ -73,6 +75,15 @@ struct omap_device {
 	s8				pm_lat_level;
 	u8				hwmods_cnt;
 	u8				_state;
+
+};
+
+/* Linked list for the devices constraints entries */
+struct omap_device_constraints_entry {
+	struct device			*req_dev;
+	void				*target;
+	unsigned long			constraint_value;
+	struct plist_node		node;
 };
 
 /* Device driver interface (call via platform_data fn ptrs) */
@@ -107,6 +118,9 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
 int omap_device_align_pm_lat(struct platform_device *pdev,
 			     u32 new_wakeup_lat_limit);
 struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+				   struct device *req_dev,
+				   struct device *dev, long t);
 u32 omap_device_get_context_loss_count(struct platform_device *pdev);
 
 /* Other */
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 65bcad4..f27110e 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -597,6 +597,7 @@ int omap_hwmod_for_each_by_class(const char *classname,
 				 void *user);
 
 int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state);
+int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency);
 u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh);
 
 /*
diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
index c8b4e4c..4709f83 100644
--- a/arch/arm/plat-omap/omap-pm-constraints.c
+++ b/arch/arm/plat-omap/omap-pm-constraints.c
@@ -24,6 +24,7 @@
 /* Interface documentation is in mach/omap-pm.h */
 #include <plat/omap-pm.h>
 #include <plat/omap_device.h>
+#include <plat/common.h>
 
 static bool off_mode_enabled;
 static u32 dummy_context_loss_counter;
@@ -32,35 +33,46 @@ static u32 dummy_context_loss_counter;
  * Device-driver-originated constraints (via board-*.c files)
  */
 
-int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
+/*
+ * Generic function to omap_device layer for the constraints API.
+ */
+static int omap_pm_set_dev_constraint(enum omap_pm_constraint_class class,
+				      struct device *req_dev,
+				      struct device *dev, long t)
 {
-	if (!dev || t < -1) {
+	int ret = 0;
+
+	if (!req_dev || !dev || t < -1) {
 		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
 		return -EINVAL;
-	};
-
-	if (t == -1)
-		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
-			 "dev %s\n", dev_name(dev));
-	else
-		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+	}
 
-	/*
-	 * For current Linux, this needs to map the MPU to a
-	 * powerdomain, then go through the list of current max lat
-	 * constraints on the MPU and find the smallest.  If
-	 * the latency constraint has changed, the code should
-	 * recompute the state to enter for the next powerdomain
-	 * state.
-	 *
-	 * TI CDP code can call constraint_set here.
-	 */
+	/* Try to catch non omap_device for dev */
+	if (dev->parent == &omap_device_parent) {
+		if (t == -1)
+			pr_debug("OMAP PM: remove constraint of class %d "
+				 "from req_dev %s on dev %s\n",
+				 class, dev_name(req_dev), dev_name(dev));
+		else
+			pr_debug("OMAP PM: add constraint of class %d "
+				 "from req_dev %s on dev %s, t = %ld\n",
+				 class, dev_name(req_dev), dev_name(dev), t);
+
+		/* Call the omap_device API */
+		ret = omap_device_set_dev_constraint(class, req_dev, dev, t);
+	} else {
+		pr_err("OMAP-PM set_wakeup_lat: Error: platform device "
+		       "not valid\n");
+		return -EINVAL;
+	}
 
-	return 0;
+	return ret;
 }
 
-int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
+/*
+ * omap_pm_set_min_bus_tput - set/release bus throughput constraints
+ */
+int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
 {
 	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
 	    agent_id != OCP_TARGET_AGENT)) {
@@ -68,83 +80,56 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
 		return -EINVAL;
 	};
 
-	if (r == 0)
-		pr_debug("OMAP PM: remove min bus tput constraint: "
-			 "dev %s for agent_id %d\n", dev_name(dev), agent_id);
-	else
-		pr_debug("OMAP PM: add min bus tput constraint: "
-			 "dev %s for agent_id %d: rate %ld KiB\n",
-			 dev_name(dev), agent_id, r);
-
 	/*
-	 * This code should model the interconnect and compute the
-	 * required clock frequency, convert that to a VDD2 OPP ID, then
-	 * set the VDD2 OPP appropriately.
-	 *
-	 * TI CDP code can call constraint_set here on the VDD2 OPP.
+	 * This code calls the generic omap_device API function
+	 * omap_pm_set_dev_constraint with the class
+	 * OMAP_PM_CONSTRAINT_THROUGHPUT. omap_pm_set_dev_constraint
+	 * should manage the constraints lists and call the appropriate
+	 * low level code that models the interconnect, computes the required
+	 * clock frequency, converts that to a VDD2 OPP ID and sets the
+	 * VDD2 OPP appropriately.
 	 */
-
-	return 0;
+	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_THROUGHPUT,
+					  dev, dev, r);
 }
 
+/*
+ * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
+ * constraints
+ */
 int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
 				   long t)
 {
-	if (!req_dev || !dev || t < -1) {
-		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
-		return -EINVAL;
-	};
-
-	if (t == -1)
-		pr_debug("OMAP PM: remove max device latency constraint: "
-			 "dev %s\n", dev_name(dev));
-	else
-		pr_debug("OMAP PM: add max device latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
-
-	/*
-	 * For current Linux, this needs to map the device to a
-	 * powerdomain, then go through the list of current max lat
-	 * constraints on that powerdomain and find the smallest.  If
-	 * the latency constraint has changed, the code should
-	 * recompute the state to enter for the next powerdomain
-	 * state.  Conceivably, this code should also determine
-	 * whether to actually disable the device clocks or not,
-	 * depending on how long it takes to re-enable the clocks.
-	 *
-	 * TI CDP code can call constraint_set here.
-	 */
-
-	return 0;
+	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
+					  req_dev, dev, t);
 }
 
-int omap_pm_set_max_sdma_lat(struct device *dev, long t)
+/*
+ * omap_pm_set_max_mpu_wakeup_lat - set/release MPU wake-up latency
+ * constraints
+ *
+ * Maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
+ * as constraint class and the MPU device as constraints target.
+ */
+int omap_pm_set_max_mpu_wakeup_lat(struct device *req_dev, long t)
 {
-	if (!dev || t < -1) {
-		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
-		return -EINVAL;
-	};
-
-	if (t == -1)
-		pr_debug("OMAP PM: remove max DMA latency constraint: "
-			 "dev %s\n", dev_name(dev));
-	else
-		pr_debug("OMAP PM: add max DMA latency constraint: "
-			 "dev %s, t = %ld usec\n", dev_name(dev), t);
-
-	/*
-	 * For current Linux PM QOS params, this code should scan the
-	 * list of maximum CPU and DMA latencies and select the
-	 * smallest, then set cpu_dma_latency pm_qos_param
-	 * accordingly.
-	 *
-	 * For future Linux PM QOS params, with separate CPU and DMA
-	 * latency params, this code should just set the dma_latency param.
-	 *
-	 * TI CDP code can call constraint_set here.
-	 */
+	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
+					  req_dev, omap2_get_mpuss_device(),
+					  t);
+}
 
-	return 0;
+/*
+ * omap_pm_set_max_sdma_lat - set/release SDMA start latency
+ * constraints
+ *
+ * Currently maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
+ * as constraint class and the L3 device as constraints target.
+ */
+int omap_pm_set_max_sdma_lat(struct device *req_dev, long t)
+{
+	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
+					  req_dev, omap2_get_l3_device(),
+					  t);
 }
 
 int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
diff --git a/arch/arm/plat-omap/omap-pm-noop.c b/arch/arm/plat-omap/omap-pm-noop.c
index b0471bb2..7868edc 100644
--- a/arch/arm/plat-omap/omap-pm-noop.c
+++ b/arch/arm/plat-omap/omap-pm-noop.c
@@ -61,7 +61,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
 	return 0;
 }
 
-int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
+int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
 {
 	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
 	    agent_id != OCP_TARGET_AGENT)) {
diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index 9bbda9a..b33b7fa 100644
--- a/arch/arm/plat-omap/omap_device.c
+++ b/arch/arm/plat-omap/omap_device.c
@@ -292,10 +292,189 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
 	}
 }
 
+/* plist that stores the devices wake-up latency constraints */
+static struct plist_head omap_device_wkup_lat_constraints_list;
+/* Spinlock that protects the constraints lists */
+static spinlock_t omap_device_constraints_lock;
+/* Mutex that protects the constraints lists ops */
+static struct mutex omap_device_constraints_mutex;
+
+/*
+ * omap_device_store_constraint: add/update/remove a constraint from a plist
+ *
+ * @constraints_list: plist to use
+ * @req_dev: constraint requester, used to track the requests
+ * @target: target which the constraint applies to (e.g. power domain ID or
+ *  ptr for wake-up latency constraints)
+ * @value: constraint value. The plist is sorted by the value. -1 remove the
+ *  constraint from the list
+ *
+ * Returns the strongest constraint value for the given target, 0 in the
+ * case there is no constraint on the given target or a negative value in
+ * case of error.
+ * The caller must check the validity of the parameters.
+ */
+static long omap_device_store_constraint(struct plist_head *constraints_list,
+					 struct device *req_dev, void *target,
+					 long value)
+{
+	struct omap_device_constraints_entry *user;
+	int found = 0, ret = 0;
+
+	mutex_lock(&omap_device_constraints_mutex);
+
+	/* Check if the constraint requester is already in the list */
+	plist_for_each_entry(user, constraints_list, node) {
+		if (user->req_dev == req_dev) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (value >= 0) {
+		/* Add new entry to the list or update existing request */
+		if (found &&
+		    user->constraint_value == value &&
+		    user->target == target) {
+			goto exit_ok;
+		} else if (!found) {
+			user = kzalloc(
+				sizeof(struct omap_device_constraints_entry),
+				GFP_KERNEL);
+			if (!user) {
+				pr_err("%s: FATAL ERROR: kzalloc failed\n",
+				       __func__);
+				ret = -ENOMEM;
+				goto exit_error;
+			}
+			user->req_dev = req_dev;
+		} else {
+			plist_del(&user->node, constraints_list);
+		}
+
+		plist_node_init(&user->node, value);
+		plist_add(&user->node, constraints_list);
+		user->node.prio = user->constraint_value = value;
+		user->target = target;
+	} else {
+		/* Remove the constraint from the list */
+		if (!found) {
+			pr_err("%s: Error: no prior constraint to release\n",
+			       __func__);
+			ret = -EINVAL;
+			goto exit_error;
+		}
+
+		plist_del(&user->node, constraints_list);
+		kfree(user);
+	}
+
+exit_ok:
+	/* Find the strongest constraint for the given target */
+	ret = 0;
+	plist_for_each_entry(user, constraints_list, node) {
+		if (user->target == target) {
+			ret = user->constraint_value;
+			break;
+		}
+	}
+
+exit_error:
+	mutex_unlock(&omap_device_constraints_mutex);
+
+	return ret;
+}
 
 /* Public functions for use by core code */
 
 /**
+ * omap_device_set_max_dev_wakeup_lat - set/release a device constraint
+ * @class: constraint class
+ * @dev: device to apply the constraint to. Must have an associated omap_device
+ * @req_dev: constraint requester, used for tracking the constraints
+ *
+ * Using the primary hwmod, set/release a device constraint for the dev
+ * device, requested by the req_dev device. Depending of the constraint class
+ * this code calls the appropriate low level code, e.g. power domain for
+ * the wake-up latency constraints.
+ *
+ * If any hwmods exist for the omap_device assoiated with @dev and @req_dev,
+ * set/release the constraint for the corresponding hwmods, otherwise return
+ * -EINVAL.
+ */
+int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
+				   struct device *req_dev,
+				   struct device *dev, long t)
+{
+	struct omap_device *od;
+	struct omap_hwmod *oh;
+	struct platform_device *pdev;
+	struct powerdomain *pwrdm = NULL;
+	u32 ret = -EINVAL;
+
+	/* Look for the platform device for dev */
+	pdev = to_platform_device(dev);
+
+	/* Try to catch non platform devices. */
+	if (pdev->name == NULL) {
+		pr_err("%s: Error: platform device for device %s not valid\n",
+		       __func__, dev_name(dev));
+		return -EINVAL;
+	}
+
+	/* Find the associated omap_device for dev */
+	od = _find_by_pdev(pdev);
+	if (!(od->hwmods_cnt)) {
+		pr_err("%s: Error: No hwmod for device %s\n",
+		       __func__, dev_name(dev));
+		return -EINVAL;
+	}
+
+	/* Find the associated omap_hwmod for dev */
+	oh = od->hwmods[0];
+
+	switch (class) {
+	case OMAP_PM_CONSTRAINT_WKUP_LAT:
+		/* Find the pwrdm associated to dev */
+		pwrdm = omap_device_get_pwrdm(od);
+		if (!pwrdm) {
+			pr_err("%s: Error: No pwrdm for device %s\n",
+			       __func__, dev_name(dev));
+			ret = -EINVAL;
+			break;
+		}
+
+		/*
+		 * Store the constraint in the appropriate list and find the
+		 * strongest constraint for the given pwrdm
+		 */
+		ret = omap_device_store_constraint(
+					&omap_device_wkup_lat_constraints_list,
+					req_dev, (void *) pwrdm, t);
+
+		/* Apply the constraint to the corresponding pwrdm */
+		if (ret >= 0) {
+			ret = omap_hwmod_update_power_state(oh, ret);
+		} else {
+			pr_err("%s: Error storing the constraint for device "
+			       "%s\n", __func__, dev_name(dev));
+		}
+
+		break;
+	case OMAP_PM_CONSTRAINT_THROUGHPUT:
+		WARN(1, "OMAP PM: %s: Bus throughput constraint class \
+		     not implemented\n", __func__);
+		ret = -EINVAL;
+		break;
+	default:
+		WARN(1, "OMAP PM: %s: invalid constraint class %d",
+		     __func__, class);
+	}
+
+	return ret;
+}
+
+/**
  * omap_device_get_context_loss_count - get lost context count
  * @od: struct omap_device *
  *
@@ -824,6 +1003,14 @@ struct device omap_device_parent = {
 
 static int __init omap_device_init(void)
 {
+	/* Initialize priority ordered list for wakeup latency constraint */
+	spin_lock_init(&omap_device_constraints_lock);
+	plist_head_init(&omap_device_wkup_lat_constraints_list,
+			&omap_device_constraints_lock);
+
+	/* res_mutex protects res_list add and del ops */
+	mutex_init(&omap_device_constraints_mutex);
+
 	return device_register(&omap_device_parent);
 }
 core_initcall(omap_device_init);
-- 
1.7.2.3

Re: [PATCH 2/2] OMAP: PM: implement devices constraints APIs

[Jean Pihet]

Hi,

This patch is sent as en early review request, the testing is still on-going.
I will post the updated series (with a new revision number) as soon as possible.

I have some inlined comments, questions and concerns about it.
Can you please check?

On Wed, Mar 9, 2011 at 8:19 PM, Jean Pihet <jean.pihet@newoldbits.com> wrote:
> Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
> creating a unified API which calls omap_device_set_dev_constraint
> for all classes of constraints (devices wake-up latency, devices
> throughput...).
> The implementation of the constraints framework is at the omap_device
> level: management and storage of the constraints, dispatching of the
> constraints to the appropriate low level layers.
>
> NOTE: only works for devices which have been converted to use
>      omap_device/omap_hwmod.
>
> Longer term, we could possibly remove this API from the OMAP PM layer,
> and instead directly use the device level API.
>
> For the devices wake-up latency constraints, the power domains get
> the next power state programmed directly in the registers via
> pwrdm_wakeuplat_update_pwrst.
>
> Note about PM QOS: the MPU and CORE power domains get the next power
> state via cpuidle, which get the strongest wake-up latency constraint
> by querying PM QOS. The usage of PM QOS is temporary, until a generic
> solution is in place.
>
> Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
> and PM QOS frameworks.
>
> Signed-off-by: Jean Pihet <j-pihet@ti.com>
> Cc: Vibhore Vardhan <vvardhan@ti.com>
> ---
>  arch/arm/mach-omap2/omap_hwmod.c              |   29 ++++-
>  arch/arm/mach-omap2/powerdomain.c             |   99 +++++++++++++
>  arch/arm/mach-omap2/powerdomain.h             |   24 +++-
>  arch/arm/mach-omap2/powerdomains3xxx_data.c   |   63 +++++++++
>  arch/arm/plat-omap/include/plat/omap-pm.h     |    6 +-
>  arch/arm/plat-omap/include/plat/omap_device.h |   14 ++
>  arch/arm/plat-omap/include/plat/omap_hwmod.h  |    1 +
>  arch/arm/plat-omap/omap-pm-constraints.c      |  161 ++++++++++------------
>  arch/arm/plat-omap/omap-pm-noop.c             |    2 +-
>  arch/arm/plat-omap/omap_device.c              |  187 +++++++++++++++++++++++++
>  10 files changed, 493 insertions(+), 93 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index cf8cc9b..8caf2c5 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -142,6 +142,7 @@
>  #include "powerdomain.h"
>  #include <plat/clock.h>
>  #include <plat/omap_hwmod.h>
> +#include <plat/omap_device.h>
>  #include <plat/prcm.h>
>
>  #include "cm2xxx_3xxx.h"
> @@ -2277,11 +2278,37 @@ ohsps_unlock:
>        return ret;
>  }
>
> +/*
> + * omap_hwmod_update_power_state - Update the power domain power state of
> + * @oh
> + *
> + * @oh: struct omap_hwmod* to which the requesting device belongs to.
> + * @min_latency: the allowed wake-up latency for the power domain of @oh.
> + *
> + * Finds the power domain next power state that fulfills the constraint.
> + * Applies the constraint to the power domain by calling
> + * pwrdm_wakeuplat_update_pwrst.
> + *
> + * Returns 0 upon success.
> + */
> +int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency)
> +{
> +       struct powerdomain *pwrdm = omap_hwmod_get_pwrdm(oh);
> +
> +       if (!PTR_ERR(pwrdm)) {
> +               pr_err("omap_hwmod: Error: could not find parent "
> +                       "powerdomain for %s\n", oh->name);
> +               return -EINVAL;
> +       }
> +
> +       return pwrdm_wakeuplat_update_pwrst(pwrdm, min_latency);
> +}
> +
>  /**
>  * omap_hwmod_get_context_loss_count - get lost context count
>  * @oh: struct omap_hwmod *
>  *
> - * Query the powerdomain of of @oh to get the context loss
> + * Query the powerdomain of @oh to get the context loss
>  * count for this device.
>  *
>  * Returns the context loss count of the powerdomain assocated with @oh
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index eaed0df..496f245 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -19,6 +19,7 @@
>  #include <linux/list.h>
>  #include <linux/errno.h>
>  #include <linux/string.h>
> +
>  #include "cm2xxx_3xxx.h"
>  #include "prcm44xx.h"
>  #include "cm44xx.h"
> @@ -176,6 +177,104 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
>        return 0;
>  }
>
> +/*
> + * Test if the current powerdomain is MPU or CORE
> + *
> + * This function is only used by pwrdm_wakeuplat_update_pwrst
> + * which applies the MPU and CORE power domains constraints using PM QOS.
> + *
> + * This will disappear when all power domains will be controlled directly
> + * from the wake-up latency constraints framework
> + */
> +static inline int is_pwrdm_mpu_or_core(struct powerdomain *pwrdm)
> +{
> +       if ((strncmp(pwrdm->name, "mpu_pwrdm", 9) == 0) ||
> +           (strncmp(pwrdm->name, "core_pwrdm", 10) == 0))
> +               return 1;
> +       else
> +               return 0;
> +}
> +
> +/**
> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
> + * @min_latency: the allowed wake-up latency for the given power domain.
> + *
> + * Finds the power domain next power state that fulfills the constraint.
> + * Programs a new target state if it is different from current power state.
> + *
> + * Returns 0 upon success.
> + */
> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency)
> +{
> +       int ret = 0, new_state = 0;
> +
> +       if (!pwrdm) {
> +               WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
> +               return -EINVAL;
> +       }
> +
> +       /*
> +        * Apply constraints to MPU and CORE via the PM QOS API.
> +        * Every power domain struct has a pm_qos_request_list field
> +        */
> +       if (is_pwrdm_mpu_or_core(pwrdm)) {
> +               if (pm_qos_request_active(&(pwrdm->pm_qos_request)))
> +                       pm_qos_remove_request(&(pwrdm->pm_qos_request));
> +
> +               if (min_latency >= 0)
> +                       pm_qos_add_request(&(pwrdm->pm_qos_request),
> +                                          PM_QOS_CPU_DMA_LATENCY,
> +                                          min_latency);
> +               return 0;
> +       }
> +
> +       /*
> +        * Apply constraints to pwrdm other than MPU and CORE by programming
> +        * the pwrdm next power state.
> +        */
> +
> +       /* Find power state with wakeup latency < minimum constraint */
> +       for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
> +               if (min_latency == -1 ||
> +                   pwrdm->wakeup_lat[new_state] <= min_latency)
> +                       break;
> +       }
> +
> +       switch (new_state) {
> +       case PWRDM_FUNC_PWRST_OFF:
> +               new_state = PWRDM_POWER_OFF;
> +               break;
> +       case PWRDM_FUNC_PWRST_OSWR:
> +               pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
> +               new_state = PWRDM_POWER_RET;
> +               break;
> +       case PWRDM_FUNC_PWRST_CSWR:
> +               pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
> +               new_state = PWRDM_POWER_RET;
> +               break;
> +       case PWRDM_FUNC_PWRST_ON:
> +               new_state = PWRDM_POWER_ON;
> +               break;
> +       default:
> +               pr_warn("powerdomain: requested latency constraint not "
> +                       "supported %s set to ON state\n", pwrdm->name);
> +               new_state = PWRDM_POWER_ON;
> +               break;
> +       }
> +
> +       if (pwrdm_read_pwrst(pwrdm) != new_state) {
> +               ret = omap_set_pwrdm_state(pwrdm, new_state);

The function pwrdms_setup (called from omap3_pm_init for every pwrdm)
runs late in the boot process and so it overwrites the registers
values programmed by omap_set_pwrdm_state with the default values.
Could the default values get written earlier in the boot process (e.g.
at hwmod init) before the devices can put constraints on the power
domains?

> +       }
> +
> +       pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
> +                "min_latency=%ld, set_state=%d\n", pwrdm->name,
> +                pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
> +                pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
> +
> +       return ret;
> +}
> +
>  /* Public functions */
>
>  /**
> diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
> index 0b7a357..c796469 100644
> --- a/arch/arm/mach-omap2/powerdomain.h
> +++ b/arch/arm/mach-omap2/powerdomain.h
> @@ -19,7 +19,10 @@
>
>  #include <linux/types.h>
>  #include <linux/list.h>
> -
> +#include <linux/plist.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/pm_qos_params.h>
>  #include <linux/atomic.h>
>
>  #include <plat/cpu.h>
> @@ -46,6 +49,15 @@
>
>  #define PWRSTS_OFF_RET_ON      (PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))
>
> +/* Powerdomain functional power states */
> +#define PWRDM_FUNC_PWRST_OFF   0x0
> +#define PWRDM_FUNC_PWRST_OSWR  0x1
> +#define PWRDM_FUNC_PWRST_CSWR  0x2
> +#define PWRDM_FUNC_PWRST_ON    0x3
> +
> +#define PWRDM_MAX_FUNC_PWRSTS  4
> +
> +#define UNSUP_STATE            -1
>
>  /* Powerdomain flags */
>  #define PWRDM_HAS_HDWR_SAR     (1 << 0) /* hardware save-and-restore support */
> @@ -96,7 +108,11 @@ struct powerdomain;
>  * @state_counter:
>  * @timer:
>  * @state_timer:
> - *
> + * @wakeup_lat: wakeup latencies for possible powerdomain power states
> + * Note about the wakeup latencies ordering: the values must be sorted
> + *  in decremental order
> + * @pm_qos_request: PM QOS handle, only used to control the MPU and CORE power
> + *  domains states; to be removed when a generic solution is in place.
>  * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
>  */
>  struct powerdomain {
> @@ -121,6 +137,8 @@ struct powerdomain {
>        s64 timer;
>        s64 state_timer[PWRDM_MAX_PWRSTS];
>  #endif
> +       const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
> +       struct pm_qos_request_list pm_qos_request;
>  };
>
>  /**
> @@ -210,6 +228,8 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
>  int pwrdm_pre_transition(void);
>  int pwrdm_post_transition(void);
>  int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
> +
> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency);
>  u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
>
>  extern void omap2xxx_powerdomains_init(void);
> diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
> index e1bec56..64973d1 100644
> --- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
> +++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
> @@ -31,6 +31,9 @@
>
>  /*
>  * Powerdomains
> + *
> + * The wakeup_lat values are derived from measurements on
> + * the actual target.
>  */
>
>  static struct powerdomain iva2_pwrdm = {
> @@ -52,6 +55,12 @@ static struct powerdomain iva2_pwrdm = {
>                [2] = PWRSTS_OFF_ON,
>                [3] = PWRDM_POWER_ON,
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 1100,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 350,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain mpu_3xxx_pwrdm = {
> @@ -68,6 +77,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
>        .pwrsts_mem_on    = {
>                [0] = PWRSTS_OFF_ON,
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 95,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 45,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  /*
> @@ -98,6 +113,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
>                [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>                [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 100,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 60,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain core_3xxx_es3_1_pwrdm = {
> @@ -121,6 +142,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
>                [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>                [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 100,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 60,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain dss_pwrdm = {
> @@ -136,6 +163,12 @@ static struct powerdomain dss_pwrdm = {
>        .pwrsts_mem_on    = {
>                [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 70,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 20,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  /*
> @@ -157,6 +190,12 @@ static struct powerdomain sgx_pwrdm = {
>        .pwrsts_mem_on    = {
>                [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 1000,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain cam_pwrdm = {
> @@ -172,6 +211,12 @@ static struct powerdomain cam_pwrdm = {
>        .pwrsts_mem_on    = {
>                [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 850,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 35,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain per_pwrdm = {
> @@ -187,6 +232,12 @@ static struct powerdomain per_pwrdm = {
>        .pwrsts_mem_on    = {
>                [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 200,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 110,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain emu_pwrdm = {
> @@ -201,6 +252,12 @@ static struct powerdomain neon_pwrdm = {
>        .omap_chip        = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
>        .pwrsts           = PWRSTS_OFF_RET_ON,
>        .pwrsts_logic_ret = PWRDM_POWER_RET,
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 200,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 35,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain usbhost_pwrdm = {
> @@ -223,6 +280,12 @@ static struct powerdomain usbhost_pwrdm = {
>        .pwrsts_mem_on    = {
>                [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>        },
> +       .wakeup_lat = {
> +               [PWRDM_FUNC_PWRST_OFF] = 800,
> +               [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +               [PWRDM_FUNC_PWRST_CSWR] = 150,
> +               [PWRDM_FUNC_PWRST_ON] = 0,
> +       },
>  };
>
>  static struct powerdomain dpll1_pwrdm = {
> diff --git a/arch/arm/plat-omap/include/plat/omap-pm.h b/arch/arm/plat-omap/include/plat/omap-pm.h
> index c0a7520..16f9e84 100644
> --- a/arch/arm/plat-omap/include/plat/omap-pm.h
> +++ b/arch/arm/plat-omap/include/plat/omap-pm.h
> @@ -70,6 +70,10 @@ void omap_pm_if_exit(void);
>  * Device-driver-originated constraints (via board-*.c files, platform_data)
>  */
>
> +enum omap_pm_constraint_class {
> +       OMAP_PM_CONSTRAINT_WKUP_LAT,
> +       OMAP_PM_CONSTRAINT_THROUGHPUT
> +};
>
>  /**
>  * omap_pm_set_max_mpu_wakeup_lat - set the maximum MPU wakeup latency
> @@ -137,7 +141,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t);
>  * Returns -EINVAL for an invalid argument, -ERANGE if the constraint
>  * is not satisfiable, or 0 upon success.
>  */
> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r);
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r);
>
>
>  /**
> diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
> index e4c349f..d4766c4 100644
> --- a/arch/arm/plat-omap/include/plat/omap_device.h
> +++ b/arch/arm/plat-omap/include/plat/omap_device.h
> @@ -32,9 +32,11 @@
>  #define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
>
>  #include <linux/kernel.h>
> +#include <linux/plist.h>
>  #include <linux/platform_device.h>
>
>  #include <plat/omap_hwmod.h>
> +#include <plat/omap-pm.h>
>
>  extern struct device omap_device_parent;
>
> @@ -73,6 +75,15 @@ struct omap_device {
>        s8                              pm_lat_level;
>        u8                              hwmods_cnt;
>        u8                              _state;
> +
> +};
> +
> +/* Linked list for the devices constraints entries */
> +struct omap_device_constraints_entry {
> +       struct device                   *req_dev;
> +       void                            *target;
> +       unsigned long                   constraint_value;
> +       struct plist_node               node;
>  };
>
>  /* Device driver interface (call via platform_data fn ptrs) */
> @@ -107,6 +118,9 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
>  int omap_device_align_pm_lat(struct platform_device *pdev,
>                             u32 new_wakeup_lat_limit);
>  struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
> +int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
> +                                  struct device *req_dev,
> +                                  struct device *dev, long t);
>  u32 omap_device_get_context_loss_count(struct platform_device *pdev);
>
>  /* Other */
> diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
> index 65bcad4..f27110e 100644
> --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
> +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
> @@ -597,6 +597,7 @@ int omap_hwmod_for_each_by_class(const char *classname,
>                                 void *user);
>
>  int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state);
> +int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency);
>  u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh);
>
>  /*
> diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
> index c8b4e4c..4709f83 100644
> --- a/arch/arm/plat-omap/omap-pm-constraints.c
> +++ b/arch/arm/plat-omap/omap-pm-constraints.c
> @@ -24,6 +24,7 @@
>  /* Interface documentation is in mach/omap-pm.h */
>  #include <plat/omap-pm.h>
>  #include <plat/omap_device.h>
> +#include <plat/common.h>
>
>  static bool off_mode_enabled;
>  static u32 dummy_context_loss_counter;
> @@ -32,35 +33,46 @@ static u32 dummy_context_loss_counter;
>  * Device-driver-originated constraints (via board-*.c files)
>  */
>
> -int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
> +/*
> + * Generic function to omap_device layer for the constraints API.
> + */
> +static int omap_pm_set_dev_constraint(enum omap_pm_constraint_class class,
> +                                     struct device *req_dev,
> +                                     struct device *dev, long t)
>  {
> -       if (!dev || t < -1) {
> +       int ret = 0;
> +
> +       if (!req_dev || !dev || t < -1) {
>                WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>                return -EINVAL;
> -       };
> -
> -       if (t == -1)
> -               pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
> -                        "dev %s\n", dev_name(dev));
> -       else
> -               pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
> -                        "dev %s, t = %ld usec\n", dev_name(dev), t);
> +       }
>
> -       /*
> -        * For current Linux, this needs to map the MPU to a
> -        * powerdomain, then go through the list of current max lat
> -        * constraints on the MPU and find the smallest.  If
> -        * the latency constraint has changed, the code should
> -        * recompute the state to enter for the next powerdomain
> -        * state.
> -        *
> -        * TI CDP code can call constraint_set here.
> -        */
> +       /* Try to catch non omap_device for dev */
> +       if (dev->parent == &omap_device_parent) {
> +               if (t == -1)
> +                       pr_debug("OMAP PM: remove constraint of class %d "
> +                                "from req_dev %s on dev %s\n",
> +                                class, dev_name(req_dev), dev_name(dev));
> +               else
> +                       pr_debug("OMAP PM: add constraint of class %d "
> +                                "from req_dev %s on dev %s, t = %ld\n",
> +                                class, dev_name(req_dev), dev_name(dev), t);
> +
> +               /* Call the omap_device API */
> +               ret = omap_device_set_dev_constraint(class, req_dev, dev, t);
> +       } else {
> +               pr_err("OMAP-PM set_wakeup_lat: Error: platform device "
> +                      "not valid\n");
> +               return -EINVAL;
> +       }
>
> -       return 0;
> +       return ret;
>  }
>
> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
> +/*
> + * omap_pm_set_min_bus_tput - set/release bus throughput constraints
> + */
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
>  {
>        if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
>            agent_id != OCP_TARGET_AGENT)) {
> @@ -68,83 +80,56 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>                return -EINVAL;
>        };
>
> -       if (r == 0)
> -               pr_debug("OMAP PM: remove min bus tput constraint: "
> -                        "dev %s for agent_id %d\n", dev_name(dev), agent_id);
> -       else
> -               pr_debug("OMAP PM: add min bus tput constraint: "
> -                        "dev %s for agent_id %d: rate %ld KiB\n",
> -                        dev_name(dev), agent_id, r);
> -
>        /*
> -        * This code should model the interconnect and compute the
> -        * required clock frequency, convert that to a VDD2 OPP ID, then
> -        * set the VDD2 OPP appropriately.
> -        *
> -        * TI CDP code can call constraint_set here on the VDD2 OPP.
> +        * This code calls the generic omap_device API function
> +        * omap_pm_set_dev_constraint with the class
> +        * OMAP_PM_CONSTRAINT_THROUGHPUT. omap_pm_set_dev_constraint
> +        * should manage the constraints lists and call the appropriate
> +        * low level code that models the interconnect, computes the required
> +        * clock frequency, converts that to a VDD2 OPP ID and sets the
> +        * VDD2 OPP appropriately.
>         */
> -
> -       return 0;
> +       return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_THROUGHPUT,
> +                                         dev, dev, r);

The tput constraint API is not clear to me. What is the agent_id field
for? Can this be replaced by a requester device ptr?

>  }
>
> +/*
> + * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
> + * constraints
> + */
>  int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
>                                   long t)
>  {
> -       if (!req_dev || !dev || t < -1) {
> -               WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> -               return -EINVAL;
> -       };
> -
> -       if (t == -1)
> -               pr_debug("OMAP PM: remove max device latency constraint: "
> -                        "dev %s\n", dev_name(dev));
> -       else
> -               pr_debug("OMAP PM: add max device latency constraint: "
> -                        "dev %s, t = %ld usec\n", dev_name(dev), t);
> -
> -       /*
> -        * For current Linux, this needs to map the device to a
> -        * powerdomain, then go through the list of current max lat
> -        * constraints on that powerdomain and find the smallest.  If
> -        * the latency constraint has changed, the code should
> -        * recompute the state to enter for the next powerdomain
> -        * state.  Conceivably, this code should also determine
> -        * whether to actually disable the device clocks or not,
> -        * depending on how long it takes to re-enable the clocks.
> -        *
> -        * TI CDP code can call constraint_set here.
> -        */
> -
> -       return 0;
> +       return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
> +                                         req_dev, dev, t);
>  }
>
> -int omap_pm_set_max_sdma_lat(struct device *dev, long t)
> +/*
> + * omap_pm_set_max_mpu_wakeup_lat - set/release MPU wake-up latency
> + * constraints
> + *
> + * Maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
> + * as constraint class and the MPU device as constraints target.
> + */
> +int omap_pm_set_max_mpu_wakeup_lat(struct device *req_dev, long t)
>  {
> -       if (!dev || t < -1) {
> -               WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> -               return -EINVAL;
> -       };
> -
> -       if (t == -1)
> -               pr_debug("OMAP PM: remove max DMA latency constraint: "
> -                        "dev %s\n", dev_name(dev));
> -       else
> -               pr_debug("OMAP PM: add max DMA latency constraint: "
> -                        "dev %s, t = %ld usec\n", dev_name(dev), t);
> -
> -       /*
> -        * For current Linux PM QOS params, this code should scan the
> -        * list of maximum CPU and DMA latencies and select the
> -        * smallest, then set cpu_dma_latency pm_qos_param
> -        * accordingly.
> -        *
> -        * For future Linux PM QOS params, with separate CPU and DMA
> -        * latency params, this code should just set the dma_latency param.
> -        *
> -        * TI CDP code can call constraint_set here.
> -        */
> +       return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
> +                                         req_dev, omap2_get_mpuss_device(),
> +                                         t);
> +}
>
> -       return 0;
> +/*
> + * omap_pm_set_max_sdma_lat - set/release SDMA start latency
> + * constraints
> + *
> + * Currently maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
> + * as constraint class and the L3 device as constraints target.
> + */
> +int omap_pm_set_max_sdma_lat(struct device *req_dev, long t)
> +{
> +       return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
> +                                         req_dev, omap2_get_l3_device(),
> +                                         t);
>  }
>
>  int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
> diff --git a/arch/arm/plat-omap/omap-pm-noop.c b/arch/arm/plat-omap/omap-pm-noop.c
> index b0471bb2..7868edc 100644
> --- a/arch/arm/plat-omap/omap-pm-noop.c
> +++ b/arch/arm/plat-omap/omap-pm-noop.c
> @@ -61,7 +61,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
>        return 0;
>  }
>
> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
>  {
>        if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
>            agent_id != OCP_TARGET_AGENT)) {
> diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
> index 9bbda9a..b33b7fa 100644
> --- a/arch/arm/plat-omap/omap_device.c
> +++ b/arch/arm/plat-omap/omap_device.c
> @@ -292,10 +292,189 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
>        }
>  }
>
> +/* plist that stores the devices wake-up latency constraints */
> +static struct plist_head omap_device_wkup_lat_constraints_list;
> +/* Spinlock that protects the constraints lists */
> +static spinlock_t omap_device_constraints_lock;
> +/* Mutex that protects the constraints lists ops */
> +static struct mutex omap_device_constraints_mutex;

Is that OK to do so to define the internal variables?

> +
> +/*
> + * omap_device_store_constraint: add/update/remove a constraint from a plist
> + *
> + * @constraints_list: plist to use
> + * @req_dev: constraint requester, used to track the requests
> + * @target: target which the constraint applies to (e.g. power domain ID or
> + *  ptr for wake-up latency constraints)
> + * @value: constraint value. The plist is sorted by the value. -1 remove the
> + *  constraint from the list
> + *
> + * Returns the strongest constraint value for the given target, 0 in the
> + * case there is no constraint on the given target or a negative value in
> + * case of error.
> + * The caller must check the validity of the parameters.
> + */
> +static long omap_device_store_constraint(struct plist_head *constraints_list,
> +                                        struct device *req_dev, void *target,
> +                                        long value)
> +{
> +       struct omap_device_constraints_entry *user;
> +       int found = 0, ret = 0;
> +
> +       mutex_lock(&omap_device_constraints_mutex);
> +
> +       /* Check if the constraint requester is already in the list */
> +       plist_for_each_entry(user, constraints_list, node) {
> +               if (user->req_dev == req_dev) {
> +                       found = 1;
> +                       break;
> +               }
> +       }
> +
> +       if (value >= 0) {
> +               /* Add new entry to the list or update existing request */
> +               if (found &&
> +                   user->constraint_value == value &&
> +                   user->target == target) {
> +                       goto exit_ok;
> +               } else if (!found) {
> +                       user = kzalloc(
> +                               sizeof(struct omap_device_constraints_entry),
> +                               GFP_KERNEL);
> +                       if (!user) {
> +                               pr_err("%s: FATAL ERROR: kzalloc failed\n",
> +                                      __func__);
> +                               ret = -ENOMEM;
> +                               goto exit_error;
> +                       }
> +                       user->req_dev = req_dev;
> +               } else {
> +                       plist_del(&user->node, constraints_list);
> +               }
> +
> +               plist_node_init(&user->node, value);
> +               plist_add(&user->node, constraints_list);
> +               user->node.prio = user->constraint_value = value;
> +               user->target = target;
> +       } else {
> +               /* Remove the constraint from the list */
> +               if (!found) {
> +                       pr_err("%s: Error: no prior constraint to release\n",
> +                              __func__);
> +                       ret = -EINVAL;
> +                       goto exit_error;
> +               }
> +
> +               plist_del(&user->node, constraints_list);
> +               kfree(user);
> +       }
> +
> +exit_ok:
> +       /* Find the strongest constraint for the given target */
> +       ret = 0;
> +       plist_for_each_entry(user, constraints_list, node) {
> +               if (user->target == target) {
> +                       ret = user->constraint_value;
> +                       break;
> +               }
> +       }
This is supposed to return the higher priority from the plist, and so
the lowest constraint_value.
Although it is OK for wake-up latency it could not fit all constraints
type (e.g. throughput requires the highest value).
I will correct this.

> +
> +exit_error:
> +       mutex_unlock(&omap_device_constraints_mutex);
> +
> +       return ret;
> +}
>
>  /* Public functions for use by core code */
>
>  /**
> + * omap_device_set_max_dev_wakeup_lat - set/release a device constraint
> + * @class: constraint class
> + * @dev: device to apply the constraint to. Must have an associated omap_device
> + * @req_dev: constraint requester, used for tracking the constraints
> + *
> + * Using the primary hwmod, set/release a device constraint for the dev
> + * device, requested by the req_dev device. Depending of the constraint class
> + * this code calls the appropriate low level code, e.g. power domain for
> + * the wake-up latency constraints.
> + *
> + * If any hwmods exist for the omap_device assoiated with @dev and @req_dev,
> + * set/release the constraint for the corresponding hwmods, otherwise return
> + * -EINVAL.
> + */
> +int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
> +                                  struct device *req_dev,
> +                                  struct device *dev, long t)
> +{
> +       struct omap_device *od;
> +       struct omap_hwmod *oh;
> +       struct platform_device *pdev;
> +       struct powerdomain *pwrdm = NULL;
> +       u32 ret = -EINVAL;
> +
> +       /* Look for the platform device for dev */
> +       pdev = to_platform_device(dev);
> +
> +       /* Try to catch non platform devices. */
> +       if (pdev->name == NULL) {
> +               pr_err("%s: Error: platform device for device %s not valid\n",
> +                      __func__, dev_name(dev));
> +               return -EINVAL;
> +       }
> +
> +       /* Find the associated omap_device for dev */
> +       od = _find_by_pdev(pdev);
> +       if (!(od->hwmods_cnt)) {
> +               pr_err("%s: Error: No hwmod for device %s\n",
> +                      __func__, dev_name(dev));
> +               return -EINVAL;
> +       }
> +
> +       /* Find the associated omap_hwmod for dev */
> +       oh = od->hwmods[0];
> +
> +       switch (class) {
> +       case OMAP_PM_CONSTRAINT_WKUP_LAT:
> +               /* Find the pwrdm associated to dev */
> +               pwrdm = omap_device_get_pwrdm(od);
> +               if (!pwrdm) {
> +                       pr_err("%s: Error: No pwrdm for device %s\n",
> +                              __func__, dev_name(dev));
> +                       ret = -EINVAL;
> +                       break;
> +               }
> +
> +               /*
> +                * Store the constraint in the appropriate list and find the
> +                * strongest constraint for the given pwrdm
> +                */
> +               ret = omap_device_store_constraint(
> +                                       &omap_device_wkup_lat_constraints_list,
> +                                       req_dev, (void *) pwrdm, t);
> +
> +               /* Apply the constraint to the corresponding pwrdm */
> +               if (ret >= 0) {
> +                       ret = omap_hwmod_update_power_state(oh, ret);
> +               } else {
> +                       pr_err("%s: Error storing the constraint for device "
> +                              "%s\n", __func__, dev_name(dev));
> +               }
> +
> +               break;
> +       case OMAP_PM_CONSTRAINT_THROUGHPUT:
> +               WARN(1, "OMAP PM: %s: Bus throughput constraint class \
> +                    not implemented\n", __func__);
> +               ret = -EINVAL;
> +               break;
> +       default:
> +               WARN(1, "OMAP PM: %s: invalid constraint class %d",
> +                    __func__, class);
> +       }
> +
> +       return ret;
> +}
> +
> +/**
>  * omap_device_get_context_loss_count - get lost context count
>  * @od: struct omap_device *
>  *
> @@ -824,6 +1003,14 @@ struct device omap_device_parent = {
>
>  static int __init omap_device_init(void)
>  {
> +       /* Initialize priority ordered list for wakeup latency constraint */
> +       spin_lock_init(&omap_device_constraints_lock);
> +       plist_head_init(&omap_device_wkup_lat_constraints_list,
> +                       &omap_device_constraints_lock);
> +
> +       /* res_mutex protects res_list add and del ops */
> +       mutex_init(&omap_device_constraints_mutex);
> +
>        return device_register(&omap_device_parent);
>  }
>  core_initcall(omap_device_init);

Is it OK to initialize the list, lock and mutex here? This code runs
very early in the boot sequence (right after hwmod init).
Same remark about pwrdms_setup that overwrites the registers values.

> --
> 1.7.2.3
>
>

Thanks for looking,
Jean
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Re: [PATCH 2/2] OMAP: PM: implement devices constraints APIs

[Kevin Hilman]

Jean Pihet <jean.pihet@newoldbits.com> writes:

[...]

>> +       if (pwrdm_read_pwrst(pwrdm) != new_state) {
>> +               ret = omap_set_pwrdm_state(pwrdm, new_state);
>
> The function pwrdms_setup (called from omap3_pm_init for every pwrdm)
> runs late in the boot process and so it overwrites the registers
> values programmed by omap_set_pwrdm_state with the default values.
> Could the default values get written earlier in the boot process (e.g.
> at hwmod init) before the devices can put constraints on the power
> domains?

Yes, default vaules for each power domain's next state should probably
be written earlier in the boot.  Probably when the powerdomain is
initialized, or at least when this constraints framework is initialized.

Then, the initial states set in omap3_pm_init() can just be removed.

Kevin


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Re: [PATCH 2/2] OMAP: PM: implement devices constraints APIs

[Paul Walmsley]

Hello Jean

Thanks for working on this stuff.  Some comments based on a quick look...

On Wed, 9 Mar 2011, Jean Pihet wrote:

> Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
> creating a unified API which calls omap_device_set_dev_constraint
> for all classes of constraints (devices wake-up latency, devices
> throughput...).
> The implementation of the constraints framework is at the omap_device
> level: management and storage of the constraints, dispatching of the
> constraints to the appropriate low level layers.
> 
> NOTE: only works for devices which have been converted to use
>       omap_device/omap_hwmod.
> 
> Longer term, we could possibly remove this API from the OMAP PM layer,
> and instead directly use the device level API.
> 
> For the devices wake-up latency constraints, the power domains get
> the next power state programmed directly in the registers via
> pwrdm_wakeuplat_update_pwrst.
> 
> Note about PM QOS: the MPU and CORE power domains get the next power
> state via cpuidle, which get the strongest wake-up latency constraint
> by querying PM QOS. The usage of PM QOS is temporary, until a generic
> solution is in place.
> 
> Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
> and PM QOS frameworks.
> 
> Signed-off-by: Jean Pihet <j-pihet@ti.com>
> Cc: Vibhore Vardhan <vvardhan@ti.com>
> ---
>  arch/arm/mach-omap2/omap_hwmod.c              |   29 ++++-
>  arch/arm/mach-omap2/powerdomain.c             |   99 +++++++++++++
>  arch/arm/mach-omap2/powerdomain.h             |   24 +++-
>  arch/arm/mach-omap2/powerdomains3xxx_data.c   |   63 +++++++++
>  arch/arm/plat-omap/include/plat/omap-pm.h     |    6 +-
>  arch/arm/plat-omap/include/plat/omap_device.h |   14 ++
>  arch/arm/plat-omap/include/plat/omap_hwmod.h  |    1 +
>  arch/arm/plat-omap/omap-pm-constraints.c      |  161 ++++++++++------------
>  arch/arm/plat-omap/omap-pm-noop.c             |    2 +-
>  arch/arm/plat-omap/omap_device.c              |  187 +++++++++++++++++++++++++
>  10 files changed, 493 insertions(+), 93 deletions(-)

Please split this patch up into several patches:

- the powerdomain.h/powerdomain.c changes
- the powerdomains*_data.c changes
- any changes you want to make to the omap-pm.h interface, and if those
  require changes to the omap-pm-*.c files, change those here too
- omap_hwmod changes (if needed, which I don't think they are)
- omap_device changes
- omap-pm-constraints changes

> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> index cf8cc9b..8caf2c5 100644
> --- a/arch/arm/mach-omap2/omap_hwmod.c
> +++ b/arch/arm/mach-omap2/omap_hwmod.c
> @@ -142,6 +142,7 @@
>  #include "powerdomain.h"
>  #include <plat/clock.h>
>  #include <plat/omap_hwmod.h>
> +#include <plat/omap_device.h>
>  #include <plat/prcm.h>
>  
>  #include "cm2xxx_3xxx.h"
> @@ -2277,11 +2278,37 @@ ohsps_unlock:
>  	return ret;
>  }
>  
> +/*
> + * omap_hwmod_update_power_state - Update the power domain power state of
> + * @oh
> + *
> + * @oh: struct omap_hwmod* to which the requesting device belongs to.
> + * @min_latency: the allowed wake-up latency for the power domain of @oh.
> + *
> + * Finds the power domain next power state that fulfills the constraint.
> + * Applies the constraint to the power domain by calling
> + * pwrdm_wakeuplat_update_pwrst.
> + *
> + * Returns 0 upon success.
> + */
> +int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency)
> +{
> +	struct powerdomain *pwrdm = omap_hwmod_get_pwrdm(oh);
> +
> +	if (!PTR_ERR(pwrdm)) {
> +		pr_err("omap_hwmod: Error: could not find parent "
> +			"powerdomain for %s\n", oh->name);
> +		return -EINVAL;
> +	}
> +
> +	return pwrdm_wakeuplat_update_pwrst(pwrdm, min_latency);
> +}

I don't think this function is needed.  Might as well just take care of it 
in your omap_device code.

> +
>  /**
>   * omap_hwmod_get_context_loss_count - get lost context count
>   * @oh: struct omap_hwmod *
>   *
> - * Query the powerdomain of of @oh to get the context loss
> + * Query the powerdomain of @oh to get the context loss
>   * count for this device.
>   *
>   * Returns the context loss count of the powerdomain assocated with @oh
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index eaed0df..496f245 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -19,6 +19,7 @@
>  #include <linux/list.h>
>  #include <linux/errno.h>
>  #include <linux/string.h>
> +
>  #include "cm2xxx_3xxx.h"
>  #include "prcm44xx.h"
>  #include "cm44xx.h"
> @@ -176,6 +177,104 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
>  	return 0;
>  }
>  
> +/*
> + * Test if the current powerdomain is MPU or CORE
> + *
> + * This function is only used by pwrdm_wakeuplat_update_pwrst
> + * which applies the MPU and CORE power domains constraints using PM QOS.
> + *
> + * This will disappear when all power domains will be controlled directly
> + * from the wake-up latency constraints framework
> + */
> +static inline int is_pwrdm_mpu_or_core(struct powerdomain *pwrdm)
> +{
> +	if ((strncmp(pwrdm->name, "mpu_pwrdm", 9) == 0) ||
> +	    (strncmp(pwrdm->name, "core_pwrdm", 10) == 0))
> +		return 1;
> +	else
> +		return 0;
> +}

Please add some kind of powerdomain flag instead, set in some OMAP3 
powerdomain-specific init code, rather than strncmp().

> +
> +/**
> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
> + * @min_latency: the allowed wake-up latency for the given power domain.
> + *
> + * Finds the power domain next power state that fulfills the constraint.
> + * Programs a new target state if it is different from current power state.
> + *
> + * Returns 0 upon success.
> + */
> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency)
> +{
> +	int ret = 0, new_state = 0;
> +
> +	if (!pwrdm) {
> +		WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Apply constraints to MPU and CORE via the PM QOS API.
> +	 * Every power domain struct has a pm_qos_request_list field
> +	 */
> +	if (is_pwrdm_mpu_or_core(pwrdm)) {
> +		if (pm_qos_request_active(&(pwrdm->pm_qos_request)))
> +			pm_qos_remove_request(&(pwrdm->pm_qos_request));
> +
> +		if (min_latency >= 0)
> +			pm_qos_add_request(&(pwrdm->pm_qos_request),
> +					   PM_QOS_CPU_DMA_LATENCY,
> +					   min_latency);
> +		return 0;
> +	}
> +
> +	/*
> +	 * Apply constraints to pwrdm other than MPU and CORE by programming
> +	 * the pwrdm next power state.
> +	 */
> +
> +	/* Find power state with wakeup latency < minimum constraint */
> +	for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
> +		if (min_latency == -1 ||
> +		    pwrdm->wakeup_lat[new_state] <= min_latency)
> +			break;
> +	}
> +
> +	switch (new_state) {
> +	case PWRDM_FUNC_PWRST_OFF:
> +		new_state = PWRDM_POWER_OFF;
> +		break;
> +	case PWRDM_FUNC_PWRST_OSWR:
> +		pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
> +		new_state = PWRDM_POWER_RET;
> +		break;
> +	case PWRDM_FUNC_PWRST_CSWR:
> +		pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
> +		new_state = PWRDM_POWER_RET;
> +		break;
> +	case PWRDM_FUNC_PWRST_ON:
> +		new_state = PWRDM_POWER_ON;
> +		break;
> +	default:
> +		pr_warn("powerdomain: requested latency constraint not "
> +			"supported %s set to ON state\n", pwrdm->name);
> +		new_state = PWRDM_POWER_ON;
> +		break;
> +	}
> +
> +	if (pwrdm_read_pwrst(pwrdm) != new_state) {
> +		ret = omap_set_pwrdm_state(pwrdm, new_state);
> +	}
> +
> +	pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
> +		 "min_latency=%ld, set_state=%d\n", pwrdm->name,
> +		 pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
> +		 pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
> +
> +	return ret;
> +}
> +
>  /* Public functions */
>  
>  /**
> diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
> index 0b7a357..c796469 100644
> --- a/arch/arm/mach-omap2/powerdomain.h
> +++ b/arch/arm/mach-omap2/powerdomain.h
> @@ -19,7 +19,10 @@
>  
>  #include <linux/types.h>
>  #include <linux/list.h>
> -
> +#include <linux/plist.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <linux/pm_qos_params.h>
>  #include <linux/atomic.h>
>  
>  #include <plat/cpu.h>
> @@ -46,6 +49,15 @@
>  
>  #define PWRSTS_OFF_RET_ON	(PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))
>  
> +/* Powerdomain functional power states */
> +#define PWRDM_FUNC_PWRST_OFF	0x0
> +#define PWRDM_FUNC_PWRST_OSWR	0x1
> +#define PWRDM_FUNC_PWRST_CSWR	0x2

You'll also want an _INACTIVE state here, per:

   http://www.mail-archive.com/linux-omap@vger.kernel.org/msg43783.html

> +#define PWRDM_FUNC_PWRST_ON	0x3
> +
> +#define PWRDM_MAX_FUNC_PWRSTS	4
> +
> +#define UNSUP_STATE		-1
>  
>  /* Powerdomain flags */
>  #define PWRDM_HAS_HDWR_SAR	(1 << 0) /* hardware save-and-restore support */
> @@ -96,7 +108,11 @@ struct powerdomain;
>   * @state_counter:
>   * @timer:
>   * @state_timer:
> - *
> + * @wakeup_lat: wakeup latencies for possible powerdomain power states
> + * Note about the wakeup latencies ordering: the values must be sorted
> + *  in decremental order

Would be good to specify the unit of time here.

> + * @pm_qos_request: PM QOS handle, only used to control the MPU and CORE power
> + *  domains states; to be removed when a generic solution is in place.
>   * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
>   */
>  struct powerdomain {
> @@ -121,6 +137,8 @@ struct powerdomain {
>  	s64 timer;
>  	s64 state_timer[PWRDM_MAX_PWRSTS];
>  #endif
> +	const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
> +	struct pm_qos_request_list pm_qos_request;
>  };
>  
>  /**
> @@ -210,6 +228,8 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
>  int pwrdm_pre_transition(void);
>  int pwrdm_post_transition(void);
>  int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
> +
> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency);
>  u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
>  
>  extern void omap2xxx_powerdomains_init(void);
> diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
> index e1bec56..64973d1 100644
> --- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
> +++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
> @@ -31,6 +31,9 @@
>  
>  /*
>   * Powerdomains
> + *
> + * The wakeup_lat values are derived from measurements on
> + * the actual target.

Which type of OMAP3 chip were these measured on?  OMAP34xx/35xx, 
OMAP36xx/37xx, AM3505/17 ?

Also it would be good to know the sys_clk rate and the VDD1/2 OPPs that 
you took these measurements at.  Do you have a sense of how much these 
measurements vary based on those three factors?  Presumably, 
12MHz/125MHz/83MHz would be the worst case, for the standard OPPs anyway.

In general, if you could elaborate further how you measured these, that 
would be good.  Some of these measurements seem to be too low (described 
below).

I'm not sure if a strictly static table is the right approach for these 
measurements.  It might be good to start with a static table that 
represents the lowest possible latencies, measured with DPLL autoidle 
disabled, and then to add or remove amounts from those numbers dynamically 
based on the state of other devices.  For example, in terms of CORE, the 
AUTOEXTCLKMODE settings and the amount of time it takes the external HF 
oscillator to restart will have a major impact on the CORE OFF->ON 
measurements, potentially several milliseconds.  Similarly, if DPLL1, 2, 
or 3 have to relock, that could take quite a bit of time, potentially 
several hundred microseconds.

>   */
>  
>  static struct powerdomain iva2_pwrdm = {
> @@ -52,6 +55,12 @@ static struct powerdomain iva2_pwrdm = {
>  		[2] = PWRSTS_OFF_ON,
>  		[3] = PWRDM_POWER_ON,
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 1100,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 350,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };

Was this measured with DPLL2 autoidle enabled or disabled?

>  
>  static struct powerdomain mpu_3xxx_pwrdm = {
> @@ -68,6 +77,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRSTS_OFF_ON,
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 95,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 45,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };

Was this measured with DPLL1 autoidle enabled or disabled?

That OFF->ON time looks really low to me...

>  
>  /*
> @@ -98,6 +113,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
>  		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>  		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 100,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 60,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain core_3xxx_es3_1_pwrdm = {
> @@ -121,6 +142,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
>  		[0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>  		[1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 100,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 60,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };

The figures for the CORE powerdomain look implausibly low.  Do these 
figures represent the amount of time required to transition from the low 
power state to the point at which Linux is running again?  Or do they 
represent something else?

>  static struct powerdomain dss_pwrdm = {
> @@ -136,6 +163,12 @@ static struct powerdomain dss_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 70,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 20,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  /*
> @@ -157,6 +190,12 @@ static struct powerdomain sgx_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 1000,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain cam_pwrdm = {
> @@ -172,6 +211,12 @@ static struct powerdomain cam_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 850,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 35,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain per_pwrdm = {
> @@ -187,6 +232,12 @@ static struct powerdomain per_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 200,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 110,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain emu_pwrdm = {
> @@ -201,6 +252,12 @@ static struct powerdomain neon_pwrdm = {
>  	.omap_chip	  = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
>  	.pwrsts		  = PWRSTS_OFF_RET_ON,
>  	.pwrsts_logic_ret = PWRDM_POWER_RET,
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 200,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 35,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain usbhost_pwrdm = {
> @@ -223,6 +280,12 @@ static struct powerdomain usbhost_pwrdm = {
>  	.pwrsts_mem_on	  = {
>  		[0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>  	},
> +	.wakeup_lat = {
> +		[PWRDM_FUNC_PWRST_OFF] = 800,
> +		[PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
> +		[PWRDM_FUNC_PWRST_CSWR] = 150,
> +		[PWRDM_FUNC_PWRST_ON] = 0,
> +	},
>  };
>  
>  static struct powerdomain dpll1_pwrdm = {
> diff --git a/arch/arm/plat-omap/include/plat/omap-pm.h b/arch/arm/plat-omap/include/plat/omap-pm.h
> index c0a7520..16f9e84 100644
> --- a/arch/arm/plat-omap/include/plat/omap-pm.h
> +++ b/arch/arm/plat-omap/include/plat/omap-pm.h
> @@ -70,6 +70,10 @@ void omap_pm_if_exit(void);
>   * Device-driver-originated constraints (via board-*.c files, platform_data)
>   */
>  
> +enum omap_pm_constraint_class {
> +	OMAP_PM_CONSTRAINT_WKUP_LAT,
> +	OMAP_PM_CONSTRAINT_THROUGHPUT
> +};
>  
>  /**
>   * omap_pm_set_max_mpu_wakeup_lat - set the maximum MPU wakeup latency
> @@ -137,7 +141,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t);
>   * Returns -EINVAL for an invalid argument, -ERANGE if the constraint
>   * is not satisfiable, or 0 upon success.
>   */
> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r);
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r);

The documentation for this function states:

 To remove the interconnect throughput restriction for this device, call with r = 0.

So an unsigned long seems reasonable here?

>  
>  /**
> diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
> index e4c349f..d4766c4 100644
> --- a/arch/arm/plat-omap/include/plat/omap_device.h
> +++ b/arch/arm/plat-omap/include/plat/omap_device.h
> @@ -32,9 +32,11 @@
>  #define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
>  
>  #include <linux/kernel.h>
> +#include <linux/plist.h>
>  #include <linux/platform_device.h>
>  
>  #include <plat/omap_hwmod.h>
> +#include <plat/omap-pm.h>
>  
>  extern struct device omap_device_parent;
>  
> @@ -73,6 +75,15 @@ struct omap_device {
>  	s8				pm_lat_level;
>  	u8				hwmods_cnt;
>  	u8				_state;
> +
> +};
> +
> +/* Linked list for the devices constraints entries */
> +struct omap_device_constraints_entry {
> +	struct device			*req_dev;
> +	void				*target;
> +	unsigned long			constraint_value;
> +	struct plist_node		node;
>  };
>  
>  /* Device driver interface (call via platform_data fn ptrs) */
> @@ -107,6 +118,9 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
>  int omap_device_align_pm_lat(struct platform_device *pdev,
>  			     u32 new_wakeup_lat_limit);
>  struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
> +int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
> +				   struct device *req_dev,
> +				   struct device *dev, long t);

This should be two separate functions, one for max wakeup latency and the 
other for minimum bandwidth... discussed further below.

>  u32 omap_device_get_context_loss_count(struct platform_device *pdev);
>  
>  /* Other */
> diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
> index 65bcad4..f27110e 100644
> --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
> +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
> @@ -597,6 +597,7 @@ int omap_hwmod_for_each_by_class(const char *classname,
>  				 void *user);
>  
>  int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state);
> +int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency);
>  u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh);
>  
>  /*
> diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
> index c8b4e4c..4709f83 100644
> --- a/arch/arm/plat-omap/omap-pm-constraints.c
> +++ b/arch/arm/plat-omap/omap-pm-constraints.c
> @@ -24,6 +24,7 @@
>  /* Interface documentation is in mach/omap-pm.h */
>  #include <plat/omap-pm.h>
>  #include <plat/omap_device.h>
> +#include <plat/common.h>
>  
>  static bool off_mode_enabled;
>  static u32 dummy_context_loss_counter;
> @@ -32,35 +33,46 @@ static u32 dummy_context_loss_counter;
>   * Device-driver-originated constraints (via board-*.c files)
>   */
>  
> -int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
> +/*
> + * Generic function to omap_device layer for the constraints API.
> + */
> +static int omap_pm_set_dev_constraint(enum omap_pm_constraint_class class,
> +				      struct device *req_dev,
> +				      struct device *dev, long t)

For static functions, I'd suggest dropping the "omap_pm" prefix from the 
names of these functions, so they begin with an underscore.

>  {
> -	if (!dev || t < -1) {
> +	int ret = 0;
> +
> +	if (!req_dev || !dev || t < -1) {
>  		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>  		return -EINVAL;
> -	};
> -
> -	if (t == -1)
> -		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
> -			 "dev %s\n", dev_name(dev));
> -	else
> -		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
> -			 "dev %s, t = %ld usec\n", dev_name(dev), t);
> +	}
>  
> -	/*
> -	 * For current Linux, this needs to map the MPU to a
> -	 * powerdomain, then go through the list of current max lat
> -	 * constraints on the MPU and find the smallest.  If
> -	 * the latency constraint has changed, the code should
> -	 * recompute the state to enter for the next powerdomain
> -	 * state.
> -	 *
> -	 * TI CDP code can call constraint_set here.
> -	 */
> +	/* Try to catch non omap_device for dev */
> +	if (dev->parent == &omap_device_parent) {
> +		if (t == -1)
> +			pr_debug("OMAP PM: remove constraint of class %d "
> +				 "from req_dev %s on dev %s\n",
> +				 class, dev_name(req_dev), dev_name(dev));
> +		else
> +			pr_debug("OMAP PM: add constraint of class %d "
> +				 "from req_dev %s on dev %s, t = %ld\n",
> +				 class, dev_name(req_dev), dev_name(dev), t);
> +
> +		/* Call the omap_device API */
> +		ret = omap_device_set_dev_constraint(class, req_dev, dev, t);
> +	} else {
> +		pr_err("OMAP-PM set_wakeup_lat: Error: platform device "
> +		       "not valid\n");
> +		return -EINVAL;
> +	}
>  
> -	return 0;
> +	return ret;
>  }
>  
> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
> +/*
> + * omap_pm_set_min_bus_tput - set/release bus throughput constraints
> + */
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
>  {
>  	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
>  	    agent_id != OCP_TARGET_AGENT)) {
> @@ -68,83 +80,56 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>  		return -EINVAL;
>  	};
>  
> -	if (r == 0)
> -		pr_debug("OMAP PM: remove min bus tput constraint: "
> -			 "dev %s for agent_id %d\n", dev_name(dev), agent_id);
> -	else
> -		pr_debug("OMAP PM: add min bus tput constraint: "
> -			 "dev %s for agent_id %d: rate %ld KiB\n",
> -			 dev_name(dev), agent_id, r);
> -
>  	/*
> -	 * This code should model the interconnect and compute the
> -	 * required clock frequency, convert that to a VDD2 OPP ID, then
> -	 * set the VDD2 OPP appropriately.
> -	 *
> -	 * TI CDP code can call constraint_set here on the VDD2 OPP.
> +	 * This code calls the generic omap_device API function
> +	 * omap_pm_set_dev_constraint with the class
> +	 * OMAP_PM_CONSTRAINT_THROUGHPUT. omap_pm_set_dev_constraint
> +	 * should manage the constraints lists and call the appropriate
> +	 * low level code that models the interconnect, computes the required
> +	 * clock frequency, converts that to a VDD2 OPP ID and sets the
> +	 * VDD2 OPP appropriately.
>  	 */
> -
> -	return 0;
> +	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_THROUGHPUT,
> +					  dev, dev, r);
>  }
>  
> +/*
> + * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
> + * constraints
> + */
>  int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
>  				   long t)
>  {
> -	if (!req_dev || !dev || t < -1) {
> -		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> -		return -EINVAL;
> -	};
> -
> -	if (t == -1)
> -		pr_debug("OMAP PM: remove max device latency constraint: "
> -			 "dev %s\n", dev_name(dev));
> -	else
> -		pr_debug("OMAP PM: add max device latency constraint: "
> -			 "dev %s, t = %ld usec\n", dev_name(dev), t);
> -
> -	/*
> -	 * For current Linux, this needs to map the device to a
> -	 * powerdomain, then go through the list of current max lat
> -	 * constraints on that powerdomain and find the smallest.  If
> -	 * the latency constraint has changed, the code should
> -	 * recompute the state to enter for the next powerdomain
> -	 * state.  Conceivably, this code should also determine
> -	 * whether to actually disable the device clocks or not,
> -	 * depending on how long it takes to re-enable the clocks.
> -	 *
> -	 * TI CDP code can call constraint_set here.
> -	 */
> -
> -	return 0;
> +	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
> +					  req_dev, dev, t);
>  }
>  
> -int omap_pm_set_max_sdma_lat(struct device *dev, long t)
> +/*
> + * omap_pm_set_max_mpu_wakeup_lat - set/release MPU wake-up latency
> + * constraints
> + *
> + * Maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
> + * as constraint class and the MPU device as constraints target.
> + */
> +int omap_pm_set_max_mpu_wakeup_lat(struct device *req_dev, long t)
>  {
> -	if (!dev || t < -1) {
> -		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
> -		return -EINVAL;
> -	};
> -
> -	if (t == -1)
> -		pr_debug("OMAP PM: remove max DMA latency constraint: "
> -			 "dev %s\n", dev_name(dev));
> -	else
> -		pr_debug("OMAP PM: add max DMA latency constraint: "
> -			 "dev %s, t = %ld usec\n", dev_name(dev), t);
> -
> -	/*
> -	 * For current Linux PM QOS params, this code should scan the
> -	 * list of maximum CPU and DMA latencies and select the
> -	 * smallest, then set cpu_dma_latency pm_qos_param
> -	 * accordingly.
> -	 *
> -	 * For future Linux PM QOS params, with separate CPU and DMA
> -	 * latency params, this code should just set the dma_latency param.
> -	 *
> -	 * TI CDP code can call constraint_set here.
> -	 */
> +	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
> +					  req_dev, omap2_get_mpuss_device(),
> +					  t);
> +}
>  
> -	return 0;
> +/*
> + * omap_pm_set_max_sdma_lat - set/release SDMA start latency
> + * constraints
> + *
> + * Currently maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
> + * as constraint class and the L3 device as constraints target.
> + */
> +int omap_pm_set_max_sdma_lat(struct device *req_dev, long t)
> +{
> +	return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
> +					  req_dev, omap2_get_l3_device(),
> +					  t);
>  }
>  
>  int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
> diff --git a/arch/arm/plat-omap/omap-pm-noop.c b/arch/arm/plat-omap/omap-pm-noop.c
> index b0471bb2..7868edc 100644
> --- a/arch/arm/plat-omap/omap-pm-noop.c
> +++ b/arch/arm/plat-omap/omap-pm-noop.c
> @@ -61,7 +61,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
>  	return 0;
>  }
>  
> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
>  {
>  	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
>  	    agent_id != OCP_TARGET_AGENT)) {
> diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
> index 9bbda9a..b33b7fa 100644
> --- a/arch/arm/plat-omap/omap_device.c
> +++ b/arch/arm/plat-omap/omap_device.c
> @@ -292,10 +292,189 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
>  	}
>  }
>  
> +/* plist that stores the devices wake-up latency constraints */
> +static struct plist_head omap_device_wkup_lat_constraints_list;
> +/* Spinlock that protects the constraints lists */
> +static spinlock_t omap_device_constraints_lock;
> +/* Mutex that protects the constraints lists ops */
> +static struct mutex omap_device_constraints_mutex;
> +
> +/*
> + * omap_device_store_constraint: add/update/remove a constraint from a plist
> + *
> + * @constraints_list: plist to use
> + * @req_dev: constraint requester, used to track the requests
> + * @target: target which the constraint applies to (e.g. power domain ID or
> + *  ptr for wake-up latency constraints)
> + * @value: constraint value. The plist is sorted by the value. -1 remove the
> + *  constraint from the list
> + *
> + * Returns the strongest constraint value for the given target, 0 in the
> + * case there is no constraint on the given target or a negative value in
> + * case of error.
> + * The caller must check the validity of the parameters.
> + */
> +static long omap_device_store_constraint(struct plist_head *constraints_list,
> +					 struct device *req_dev, void *target,
> +					 long value)
> +{
> +	struct omap_device_constraints_entry *user;
> +	int found = 0, ret = 0;
> +
> +	mutex_lock(&omap_device_constraints_mutex);
> +
> +	/* Check if the constraint requester is already in the list */
> +	plist_for_each_entry(user, constraints_list, node) {
> +		if (user->req_dev == req_dev) {
> +			found = 1;
> +			break;
> +		}
> +	}
> +
> +	if (value >= 0) {

This should really be split into two functions, _add_constraint() and 
_remove_constraint().  You may wish to review Documentation/CodingStyle 
Chapter 6.

> +		/* Add new entry to the list or update existing request */
> +		if (found &&
> +		    user->constraint_value == value &&
> +		    user->target == target) {
> +			goto exit_ok;
> +		} else if (!found) {
> +			user = kzalloc(
> +				sizeof(struct omap_device_constraints_entry),
> +				GFP_KERNEL);
> +			if (!user) {
> +				pr_err("%s: FATAL ERROR: kzalloc failed\n",
> +				       __func__);
> +				ret = -ENOMEM;
> +				goto exit_error;
> +			}
> +			user->req_dev = req_dev;
> +		} else {
> +			plist_del(&user->node, constraints_list);
> +		}
> +
> +		plist_node_init(&user->node, value);
> +		plist_add(&user->node, constraints_list);
> +		user->node.prio = user->constraint_value = value;
> +		user->target = target;
> +	} else {
> +		/* Remove the constraint from the list */
> +		if (!found) {
> +			pr_err("%s: Error: no prior constraint to release\n",
> +			       __func__);
> +			ret = -EINVAL;
> +			goto exit_error;
> +		}
> +
> +		plist_del(&user->node, constraints_list);
> +		kfree(user);
> +	}
> +
> +exit_ok:
> +	/* Find the strongest constraint for the given target */
> +	ret = 0;
> +	plist_for_each_entry(user, constraints_list, node) {
> +		if (user->target == target) {
> +			ret = user->constraint_value;
> +			break;
> +		}
> +	}
> +
> +exit_error:
> +	mutex_unlock(&omap_device_constraints_mutex);
> +
> +	return ret;
> +}
>  
>  /* Public functions for use by core code */
>  
>  /**
> + * omap_device_set_max_dev_wakeup_lat - set/release a device constraint
> + * @class: constraint class
> + * @dev: device to apply the constraint to. Must have an associated omap_device
> + * @req_dev: constraint requester, used for tracking the constraints
> + *
> + * Using the primary hwmod, set/release a device constraint for the dev
> + * device, requested by the req_dev device. Depending of the constraint class
> + * this code calls the appropriate low level code, e.g. power domain for
> + * the wake-up latency constraints.
> + *
> + * If any hwmods exist for the omap_device assoiated with @dev and @req_dev,
> + * set/release the constraint for the corresponding hwmods, otherwise return
> + * -EINVAL.
> + */
> +int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
> +				   struct device *req_dev,
> +				   struct device *dev, long t)

The name of this function doesn't match what's in the kerneldoc comment.

> +{
> +	struct omap_device *od;
> +	struct omap_hwmod *oh;
> +	struct platform_device *pdev;
> +	struct powerdomain *pwrdm = NULL;
> +	u32 ret = -EINVAL;
> +
> +	/* Look for the platform device for dev */
> +	pdev = to_platform_device(dev);
> +
> +	/* Try to catch non platform devices. */
> +	if (pdev->name == NULL) {
> +		pr_err("%s: Error: platform device for device %s not valid\n",
> +		       __func__, dev_name(dev));
> +		return -EINVAL;
> +	}
> +
> +	/* Find the associated omap_device for dev */
> +	od = _find_by_pdev(pdev);
> +	if (!(od->hwmods_cnt)) {
> +		pr_err("%s: Error: No hwmod for device %s\n",
> +		       __func__, dev_name(dev));
> +		return -EINVAL;
> +	}

Please also pr_err() and bail out if there is more than one hwmod in the 
omap_device.

> +
> +	/* Find the associated omap_hwmod for dev */
> +	oh = od->hwmods[0];
> +
> +	switch (class) {
> +	case OMAP_PM_CONSTRAINT_WKUP_LAT:

Please create two different functions, 
omap_device_set_max_dev_wakeup_lat() and 
omap_device_set_min_bus_tput().  Documentation/CodingStyle chapter 6.

> +		/* Find the pwrdm associated to dev */
> +		pwrdm = omap_device_get_pwrdm(od);
> +		if (!pwrdm) {
> +			pr_err("%s: Error: No pwrdm for device %s\n",
> +			       __func__, dev_name(dev));
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		/*
> +		 * Store the constraint in the appropriate list and find the
> +		 * strongest constraint for the given pwrdm
> +		 */
> +		ret = omap_device_store_constraint(
> +					&omap_device_wkup_lat_constraints_list,
> +					req_dev, (void *) pwrdm, t);
> +
> +		/* Apply the constraint to the corresponding pwrdm */
> +		if (ret >= 0) {
> +			ret = omap_hwmod_update_power_state(oh, ret);
> +		} else {
> +			pr_err("%s: Error storing the constraint for device "
> +			       "%s\n", __func__, dev_name(dev));
> +		}
> +
> +		break;
> +	case OMAP_PM_CONSTRAINT_THROUGHPUT:
> +		WARN(1, "OMAP PM: %s: Bus throughput constraint class \
> +		     not implemented\n", __func__);
> +		ret = -EINVAL;
> +		break;
> +	default:
> +		WARN(1, "OMAP PM: %s: invalid constraint class %d",
> +		     __func__, class);
> +	}
> +
> +	return ret;
> +}
> +
> +/**
>   * omap_device_get_context_loss_count - get lost context count
>   * @od: struct omap_device *
>   *
> @@ -824,6 +1003,14 @@ struct device omap_device_parent = {
>  
>  static int __init omap_device_init(void)
>  {
> +	/* Initialize priority ordered list for wakeup latency constraint */
> +	spin_lock_init(&omap_device_constraints_lock);
> +	plist_head_init(&omap_device_wkup_lat_constraints_list,
> +			&omap_device_constraints_lock);
> +
> +	/* res_mutex protects res_list add and del ops */
> +	mutex_init(&omap_device_constraints_mutex);
> +
>  	return device_register(&omap_device_parent);
>  }
>  core_initcall(omap_device_init);
> -- 
> 1.7.2.3
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
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> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 


- Paul

Re: [PATCH 2/2] OMAP: PM: implement devices constraints APIs

[Jean Pihet]

Hi Paul,

On Thu, Mar 10, 2011 at 5:03 AM, Paul Walmsley <paul@pwsan.com> wrote:
> Hello Jean
>
> Thanks for working on this stuff.  Some comments based on a quick look...
>
> On Wed, 9 Mar 2011, Jean Pihet wrote:
>
>> Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API by
>> creating a unified API which calls omap_device_set_dev_constraint
>> for all classes of constraints (devices wake-up latency, devices
>> throughput...).
>> The implementation of the constraints framework is at the omap_device
>> level: management and storage of the constraints, dispatching of the
>> constraints to the appropriate low level layers.
>>
>> NOTE: only works for devices which have been converted to use
>>       omap_device/omap_hwmod.
>>
>> Longer term, we could possibly remove this API from the OMAP PM layer,
>> and instead directly use the device level API.
>>
>> For the devices wake-up latency constraints, the power domains get
>> the next power state programmed directly in the registers via
>> pwrdm_wakeuplat_update_pwrst.
>>
>> Note about PM QOS: the MPU and CORE power domains get the next power
>> state via cpuidle, which get the strongest wake-up latency constraint
>> by querying PM QOS. The usage of PM QOS is temporary, until a generic
>> solution is in place.
>>
>> Based on Vibhore's original patch, adapted to omap_device, omap_hwmod
>> and PM QOS frameworks.
>>
>> Signed-off-by: Jean Pihet <j-pihet@ti.com>
>> Cc: Vibhore Vardhan <vvardhan@ti.com>
>> ---
>>  arch/arm/mach-omap2/omap_hwmod.c              |   29 ++++-
>>  arch/arm/mach-omap2/powerdomain.c             |   99 +++++++++++++
>>  arch/arm/mach-omap2/powerdomain.h             |   24 +++-
>>  arch/arm/mach-omap2/powerdomains3xxx_data.c   |   63 +++++++++
>>  arch/arm/plat-omap/include/plat/omap-pm.h     |    6 +-
>>  arch/arm/plat-omap/include/plat/omap_device.h |   14 ++
>>  arch/arm/plat-omap/include/plat/omap_hwmod.h  |    1 +
>>  arch/arm/plat-omap/omap-pm-constraints.c      |  161 ++++++++++------------
>>  arch/arm/plat-omap/omap-pm-noop.c             |    2 +-
>>  arch/arm/plat-omap/omap_device.c              |  187 +++++++++++++++++++++++++
>>  10 files changed, 493 insertions(+), 93 deletions(-)
>
> Please split this patch up into several patches:
>
> - the powerdomain.h/powerdomain.c changes
> - the powerdomains*_data.c changes
> - any changes you want to make to the omap-pm.h interface, and if those
>  require changes to the omap-pm-*.c files, change those here too
> - omap_hwmod changes (if needed, which I don't think they are)
> - omap_device changes
> - omap-pm-constraints changes
Ok that will make the patch easier to read (and digest).

>
>> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
>> index cf8cc9b..8caf2c5 100644
>> --- a/arch/arm/mach-omap2/omap_hwmod.c
>> +++ b/arch/arm/mach-omap2/omap_hwmod.c
>> @@ -142,6 +142,7 @@
>>  #include "powerdomain.h"
>>  #include <plat/clock.h>
>>  #include <plat/omap_hwmod.h>
>> +#include <plat/omap_device.h>
>>  #include <plat/prcm.h>
>>
>>  #include "cm2xxx_3xxx.h"
>> @@ -2277,11 +2278,37 @@ ohsps_unlock:
>>       return ret;
>>  }
>>
>> +/*
>> + * omap_hwmod_update_power_state - Update the power domain power state of
>> + * @oh
>> + *
>> + * @oh: struct omap_hwmod* to which the requesting device belongs to.
>> + * @min_latency: the allowed wake-up latency for the power domain of @oh.
>> + *
>> + * Finds the power domain next power state that fulfills the constraint.
>> + * Applies the constraint to the power domain by calling
>> + * pwrdm_wakeuplat_update_pwrst.
>> + *
>> + * Returns 0 upon success.
>> + */
>> +int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency)
>> +{
>> +     struct powerdomain *pwrdm = omap_hwmod_get_pwrdm(oh);
>> +
>> +     if (!PTR_ERR(pwrdm)) {
>> +             pr_err("omap_hwmod: Error: could not find parent "
>> +                     "powerdomain for %s\n", oh->name);
>> +             return -EINVAL;
>> +     }
>> +
>> +     return pwrdm_wakeuplat_update_pwrst(pwrdm, min_latency);
>> +}
>
> I don't think this function is needed.  Might as well just take care of it
> in your omap_device code.
I did not have it originally but arch/arm/mach-omap2/powerdomain.h is
not included in arch/arm/plat-omap/include/plat/omap_device.c, so I
think I have to pass the call through the hwmod layer.
Please let me know if that is allowed. I do not see any pwrdm code in
omap_device.c (excepted omap_device_get_pwrdm(od)).

>
>> +
>>  /**
>>   * omap_hwmod_get_context_loss_count - get lost context count
>>   * @oh: struct omap_hwmod *
>>   *
>> - * Query the powerdomain of of @oh to get the context loss
>> + * Query the powerdomain of @oh to get the context loss
>>   * count for this device.
>>   *
>>   * Returns the context loss count of the powerdomain assocated with @oh
>> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
>> index eaed0df..496f245 100644
>> --- a/arch/arm/mach-omap2/powerdomain.c
>> +++ b/arch/arm/mach-omap2/powerdomain.c
>> @@ -19,6 +19,7 @@
>>  #include <linux/list.h>
>>  #include <linux/errno.h>
>>  #include <linux/string.h>
>> +
>>  #include "cm2xxx_3xxx.h"
>>  #include "prcm44xx.h"
>>  #include "cm44xx.h"
>> @@ -176,6 +177,104 @@ static int _pwrdm_post_transition_cb(struct powerdomain *pwrdm, void *unused)
>>       return 0;
>>  }
>>
>> +/*
>> + * Test if the current powerdomain is MPU or CORE
>> + *
>> + * This function is only used by pwrdm_wakeuplat_update_pwrst
>> + * which applies the MPU and CORE power domains constraints using PM QOS.
>> + *
>> + * This will disappear when all power domains will be controlled directly
>> + * from the wake-up latency constraints framework
>> + */
>> +static inline int is_pwrdm_mpu_or_core(struct powerdomain *pwrdm)
>> +{
>> +     if ((strncmp(pwrdm->name, "mpu_pwrdm", 9) == 0) ||
>> +         (strncmp(pwrdm->name, "core_pwrdm", 10) == 0))
>> +             return 1;
>> +     else
>> +             return 0;
>> +}
>
> Please add some kind of powerdomain flag instead, set in some OMAP3
> powerdomain-specific init code, rather than strncmp().
Ok I am looking at it. Note that this code is scheduled for removal,
in favor of a generic solution that uses pwrdm code only (i.e. not PM
QOS).

>
>> +
>> +/**
>> + * pwrdm_wakeuplat_update_pwrst - Update power domain power state if needed
>> + * @pwrdm: struct powerdomain * to which requesting device belongs to.
>> + * @min_latency: the allowed wake-up latency for the given power domain.
>> + *
>> + * Finds the power domain next power state that fulfills the constraint.
>> + * Programs a new target state if it is different from current power state.
>> + *
>> + * Returns 0 upon success.
>> + */
>> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency)
>> +{
>> +     int ret = 0, new_state = 0;
>> +
>> +     if (!pwrdm) {
>> +             WARN(1, "powerdomain: %s: invalid parameter(s)", __func__);
>> +             return -EINVAL;
>> +     }
>> +
>> +     /*
>> +      * Apply constraints to MPU and CORE via the PM QOS API.
>> +      * Every power domain struct has a pm_qos_request_list field
>> +      */
>> +     if (is_pwrdm_mpu_or_core(pwrdm)) {
>> +             if (pm_qos_request_active(&(pwrdm->pm_qos_request)))
>> +                     pm_qos_remove_request(&(pwrdm->pm_qos_request));
>> +
>> +             if (min_latency >= 0)
>> +                     pm_qos_add_request(&(pwrdm->pm_qos_request),
>> +                                        PM_QOS_CPU_DMA_LATENCY,
>> +                                        min_latency);
>> +             return 0;
>> +     }
>> +
>> +     /*
>> +      * Apply constraints to pwrdm other than MPU and CORE by programming
>> +      * the pwrdm next power state.
>> +      */
>> +
>> +     /* Find power state with wakeup latency < minimum constraint */
>> +     for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++) {
>> +             if (min_latency == -1 ||
>> +                 pwrdm->wakeup_lat[new_state] <= min_latency)
>> +                     break;
>> +     }
>> +
>> +     switch (new_state) {
>> +     case PWRDM_FUNC_PWRST_OFF:
>> +             new_state = PWRDM_POWER_OFF;
>> +             break;
>> +     case PWRDM_FUNC_PWRST_OSWR:
>> +             pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_OFF);
>> +             new_state = PWRDM_POWER_RET;
>> +             break;
>> +     case PWRDM_FUNC_PWRST_CSWR:
>> +             pwrdm_set_logic_retst(pwrdm, PWRDM_POWER_RET);
>> +             new_state = PWRDM_POWER_RET;
>> +             break;
>> +     case PWRDM_FUNC_PWRST_ON:
>> +             new_state = PWRDM_POWER_ON;
>> +             break;
>> +     default:
>> +             pr_warn("powerdomain: requested latency constraint not "
>> +                     "supported %s set to ON state\n", pwrdm->name);
>> +             new_state = PWRDM_POWER_ON;
>> +             break;
>> +     }
>> +
>> +     if (pwrdm_read_pwrst(pwrdm) != new_state) {
>> +             ret = omap_set_pwrdm_state(pwrdm, new_state);
>> +     }
>> +
>> +     pr_debug("powerdomain: %s pwrst: curr=%d, prev=%d next=%d "
>> +              "min_latency=%ld, set_state=%d\n", pwrdm->name,
>> +              pwrdm_read_pwrst(pwrdm), pwrdm_read_prev_pwrst(pwrdm),
>> +              pwrdm_read_next_pwrst(pwrdm), min_latency, new_state);
>> +
>> +     return ret;
>> +}
>> +
>>  /* Public functions */
>>
>>  /**
>> diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h
>> index 0b7a357..c796469 100644
>> --- a/arch/arm/mach-omap2/powerdomain.h
>> +++ b/arch/arm/mach-omap2/powerdomain.h
>> @@ -19,7 +19,10 @@
>>
>>  #include <linux/types.h>
>>  #include <linux/list.h>
>> -
>> +#include <linux/plist.h>
>> +#include <linux/mutex.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/pm_qos_params.h>
>>  #include <linux/atomic.h>
>>
>>  #include <plat/cpu.h>
>> @@ -46,6 +49,15 @@
>>
>>  #define PWRSTS_OFF_RET_ON    (PWRSTS_OFF_RET | (1 << PWRDM_POWER_ON))
>>
>> +/* Powerdomain functional power states */
>> +#define PWRDM_FUNC_PWRST_OFF 0x0
>> +#define PWRDM_FUNC_PWRST_OSWR        0x1
>> +#define PWRDM_FUNC_PWRST_CSWR        0x2
>
> You'll also want an _INACTIVE state here, per:
>
>   http://www.mail-archive.com/linux-omap@vger.kernel.org/msg43783.html
Is this state implemented? I do not see any code using it in the
current pm-core branch. If so can this be done later. See also the
remarks below about the latency figures.

>
>> +#define PWRDM_FUNC_PWRST_ON  0x3
>> +
>> +#define PWRDM_MAX_FUNC_PWRSTS        4
>> +
>> +#define UNSUP_STATE          -1
>>
>>  /* Powerdomain flags */
>>  #define PWRDM_HAS_HDWR_SAR   (1 << 0) /* hardware save-and-restore support */
>> @@ -96,7 +108,11 @@ struct powerdomain;
>>   * @state_counter:
>>   * @timer:
>>   * @state_timer:
>> - *
>> + * @wakeup_lat: wakeup latencies for possible powerdomain power states
>> + * Note about the wakeup latencies ordering: the values must be sorted
>> + *  in decremental order
>
> Would be good to specify the unit of time here.
Ok will do.

>
>> + * @pm_qos_request: PM QOS handle, only used to control the MPU and CORE power
>> + *  domains states; to be removed when a generic solution is in place.
>>   * @prcm_partition possible values are defined in mach-omap2/prcm44xx.h.
>>   */
>>  struct powerdomain {
>> @@ -121,6 +137,8 @@ struct powerdomain {
>>       s64 timer;
>>       s64 state_timer[PWRDM_MAX_PWRSTS];
>>  #endif
>> +     const u32 wakeup_lat[PWRDM_MAX_FUNC_PWRSTS];
>> +     struct pm_qos_request_list pm_qos_request;
>>  };
>>
>>  /**
>> @@ -210,6 +228,8 @@ int pwrdm_clkdm_state_switch(struct clockdomain *clkdm);
>>  int pwrdm_pre_transition(void);
>>  int pwrdm_post_transition(void);
>>  int pwrdm_set_lowpwrstchange(struct powerdomain *pwrdm);
>> +
>> +int pwrdm_wakeuplat_update_pwrst(struct powerdomain *pwrdm, long min_latency);
>>  u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm);
>>
>>  extern void omap2xxx_powerdomains_init(void);
>> diff --git a/arch/arm/mach-omap2/powerdomains3xxx_data.c b/arch/arm/mach-omap2/powerdomains3xxx_data.c
>> index e1bec56..64973d1 100644
>> --- a/arch/arm/mach-omap2/powerdomains3xxx_data.c
>> +++ b/arch/arm/mach-omap2/powerdomains3xxx_data.c
>> @@ -31,6 +31,9 @@
>>
>>  /*
>>   * Powerdomains
>> + *
>> + * The wakeup_lat values are derived from measurements on
>> + * the actual target.
>
> Which type of OMAP3 chip were these measured on?  OMAP34xx/35xx,
> OMAP36xx/37xx, AM3505/17 ?
Well although the comment says actual measurements have been made
(which is true!), the figures are not correct for the moment. Once the
framework is in place some more accurate measurements will be
performed.
The OMAP tracepoints implementation, the wiki information [1] and the
PMIC OFF support wiki [2] will definitely help. Also there are
measurements activities going-on at TI.

[1] http://omappedia.org/wiki/Power_Management_Device_Latencies_Measurement
[2] http://omappedia.org/wiki/TWL4030_power_scripts

>
> Also it would be good to know the sys_clk rate and the VDD1/2 OPPs that
> you took these measurements at.  Do you have a sense of how much these
> measurements vary based on those three factors?  Presumably,
> 12MHz/125MHz/83MHz would be the worst case, for the standard OPPs anyway.
>
> In general, if you could elaborate further how you measured these, that
> would be good.  Some of these measurements seem to be too low (described
> below).
That will be part of the measurements task.

>
> I'm not sure if a strictly static table is the right approach for these
> measurements.  It might be good to start with a static table that
> represents the lowest possible latencies, measured with DPLL autoidle
> disabled, and then to add or remove amounts from those numbers dynamically
> based on the state of other devices.  For example, in terms of CORE, the
> AUTOEXTCLKMODE settings and the amount of time it takes the external HF
> oscillator to restart will have a major impact on the CORE OFF->ON
> measurements, potentially several milliseconds.  Similarly, if DPLL1, 2,
> or 3 have to relock, that could take quite a bit of time, potentially
> several hundred microseconds.
The idea is to use the dynamic measurements mechanism implemented in hwmod.
Also I am still not sure on how to account for all the power domains
combination: should the latencies values be added together?

>
>>   */
>>
>>  static struct powerdomain iva2_pwrdm = {
>> @@ -52,6 +55,12 @@ static struct powerdomain iva2_pwrdm = {
>>               [2] = PWRSTS_OFF_ON,
>>               [3] = PWRDM_POWER_ON,
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 1100,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 350,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>
> Was this measured with DPLL2 autoidle enabled or disabled?
>
>>
>>  static struct powerdomain mpu_3xxx_pwrdm = {
>> @@ -68,6 +77,12 @@ static struct powerdomain mpu_3xxx_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRSTS_OFF_ON,
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 95,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 45,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>
> Was this measured with DPLL1 autoidle enabled or disabled?
>
> That OFF->ON time looks really low to me...
>
>>
>>  /*
>> @@ -98,6 +113,12 @@ static struct powerdomain core_3xxx_pre_es3_1_pwrdm = {
>>               [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>>               [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 100,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 60,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain core_3xxx_es3_1_pwrdm = {
>> @@ -121,6 +142,12 @@ static struct powerdomain core_3xxx_es3_1_pwrdm = {
>>               [0] = PWRSTS_OFF_RET_ON, /* MEM1ONSTATE */
>>               [1] = PWRSTS_OFF_RET_ON, /* MEM2ONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 100,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 60,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>
> The figures for the CORE powerdomain look implausibly low.  Do these
> figures represent the amount of time required to transition from the low
> power state to the point at which Linux is running again?  Or do they
> represent something else?
>
>>  static struct powerdomain dss_pwrdm = {
>> @@ -136,6 +163,12 @@ static struct powerdomain dss_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 70,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 20,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  /*
>> @@ -157,6 +190,12 @@ static struct powerdomain sgx_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 1000,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain cam_pwrdm = {
>> @@ -172,6 +211,12 @@ static struct powerdomain cam_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 850,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 35,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain per_pwrdm = {
>> @@ -187,6 +232,12 @@ static struct powerdomain per_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 200,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 110,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain emu_pwrdm = {
>> @@ -201,6 +252,12 @@ static struct powerdomain neon_pwrdm = {
>>       .omap_chip        = OMAP_CHIP_INIT(CHIP_IS_OMAP3430),
>>       .pwrsts           = PWRSTS_OFF_RET_ON,
>>       .pwrsts_logic_ret = PWRDM_POWER_RET,
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 200,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 35,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain usbhost_pwrdm = {
>> @@ -223,6 +280,12 @@ static struct powerdomain usbhost_pwrdm = {
>>       .pwrsts_mem_on    = {
>>               [0] = PWRDM_POWER_ON,  /* MEMONSTATE */
>>       },
>> +     .wakeup_lat = {
>> +             [PWRDM_FUNC_PWRST_OFF] = 800,
>> +             [PWRDM_FUNC_PWRST_OSWR] = UNSUP_STATE,
>> +             [PWRDM_FUNC_PWRST_CSWR] = 150,
>> +             [PWRDM_FUNC_PWRST_ON] = 0,
>> +     },
>>  };
>>
>>  static struct powerdomain dpll1_pwrdm = {
>> diff --git a/arch/arm/plat-omap/include/plat/omap-pm.h b/arch/arm/plat-omap/include/plat/omap-pm.h
>> index c0a7520..16f9e84 100644
>> --- a/arch/arm/plat-omap/include/plat/omap-pm.h
>> +++ b/arch/arm/plat-omap/include/plat/omap-pm.h
>> @@ -70,6 +70,10 @@ void omap_pm_if_exit(void);
>>   * Device-driver-originated constraints (via board-*.c files, platform_data)
>>   */
>>
>> +enum omap_pm_constraint_class {
>> +     OMAP_PM_CONSTRAINT_WKUP_LAT,
>> +     OMAP_PM_CONSTRAINT_THROUGHPUT
>> +};
>>
>>  /**
>>   * omap_pm_set_max_mpu_wakeup_lat - set the maximum MPU wakeup latency
>> @@ -137,7 +141,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t);
>>   * Returns -EINVAL for an invalid argument, -ERANGE if the constraint
>>   * is not satisfiable, or 0 upon success.
>>   */
>> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r);
>> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r);
>
> The documentation for this function states:
>
>  To remove the interconnect throughput restriction for this device, call with r = 0.
>
> So an unsigned long seems reasonable here?
Hmm good catch! I changed the parameter to be inline with the
constraints API (value=-1 means removal of the constraint). Can the
tput API be changed (and the doc acordingly)?
BTW what is the agent_id? A requester ID or ptr is needed in order to
keep track of the constraints.

>
>>
>>  /**
>> diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h
>> index e4c349f..d4766c4 100644
>> --- a/arch/arm/plat-omap/include/plat/omap_device.h
>> +++ b/arch/arm/plat-omap/include/plat/omap_device.h
>> @@ -32,9 +32,11 @@
>>  #define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
>>
>>  #include <linux/kernel.h>
>> +#include <linux/plist.h>
>>  #include <linux/platform_device.h>
>>
>>  #include <plat/omap_hwmod.h>
>> +#include <plat/omap-pm.h>
>>
>>  extern struct device omap_device_parent;
>>
>> @@ -73,6 +75,15 @@ struct omap_device {
>>       s8                              pm_lat_level;
>>       u8                              hwmods_cnt;
>>       u8                              _state;
>> +
>> +};
>> +
>> +/* Linked list for the devices constraints entries */
>> +struct omap_device_constraints_entry {
>> +     struct device                   *req_dev;
>> +     void                            *target;
>> +     unsigned long                   constraint_value;
>> +     struct plist_node               node;
>>  };
>>
>>  /* Device driver interface (call via platform_data fn ptrs) */
>> @@ -107,6 +118,9 @@ void __iomem *omap_device_get_rt_va(struct omap_device *od);
>>  int omap_device_align_pm_lat(struct platform_device *pdev,
>>                            u32 new_wakeup_lat_limit);
>>  struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
>> +int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
>> +                                struct device *req_dev,
>> +                                struct device *dev, long t);
>
> This should be two separate functions, one for max wakeup latency and the
> other for minimum bandwidth... discussed further below.
Why? The idea is to keep the code compact and not duplicated. Cf. the
function omap_device_store_constraint which is meant to manage all
constraint lists.

>
>>  u32 omap_device_get_context_loss_count(struct platform_device *pdev);
>>
>>  /* Other */
>> diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
>> index 65bcad4..f27110e 100644
>> --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
>> +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
>> @@ -597,6 +597,7 @@ int omap_hwmod_for_each_by_class(const char *classname,
>>                                void *user);
>>
>>  int omap_hwmod_set_postsetup_state(struct omap_hwmod *oh, u8 state);
>> +int omap_hwmod_update_power_state(struct omap_hwmod *oh, long min_latency);
>>  u32 omap_hwmod_get_context_loss_count(struct omap_hwmod *oh);
>>
>>  /*
>> diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
>> index c8b4e4c..4709f83 100644
>> --- a/arch/arm/plat-omap/omap-pm-constraints.c
>> +++ b/arch/arm/plat-omap/omap-pm-constraints.c
>> @@ -24,6 +24,7 @@
>>  /* Interface documentation is in mach/omap-pm.h */
>>  #include <plat/omap-pm.h>
>>  #include <plat/omap_device.h>
>> +#include <plat/common.h>
>>
>>  static bool off_mode_enabled;
>>  static u32 dummy_context_loss_counter;
>> @@ -32,35 +33,46 @@ static u32 dummy_context_loss_counter;
>>   * Device-driver-originated constraints (via board-*.c files)
>>   */
>>
>> -int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
>> +/*
>> + * Generic function to omap_device layer for the constraints API.
>> + */
>> +static int omap_pm_set_dev_constraint(enum omap_pm_constraint_class class,
>> +                                   struct device *req_dev,
>> +                                   struct device *dev, long t)
>
> For static functions, I'd suggest dropping the "omap_pm" prefix from the
> names of these functions, so they begin with an underscore.
Ok will do.

>
>>  {
>> -     if (!dev || t < -1) {
>> +     int ret = 0;
>> +
>> +     if (!req_dev || !dev || t < -1) {
>>               WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>>               return -EINVAL;
>> -     };
>> -
>> -     if (t == -1)
>> -             pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
>> -                      "dev %s\n", dev_name(dev));
>> -     else
>> -             pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
>> -                      "dev %s, t = %ld usec\n", dev_name(dev), t);
>> +     }
>>
>> -     /*
>> -      * For current Linux, this needs to map the MPU to a
>> -      * powerdomain, then go through the list of current max lat
>> -      * constraints on the MPU and find the smallest.  If
>> -      * the latency constraint has changed, the code should
>> -      * recompute the state to enter for the next powerdomain
>> -      * state.
>> -      *
>> -      * TI CDP code can call constraint_set here.
>> -      */
>> +     /* Try to catch non omap_device for dev */
>> +     if (dev->parent == &omap_device_parent) {
>> +             if (t == -1)
>> +                     pr_debug("OMAP PM: remove constraint of class %d "
>> +                              "from req_dev %s on dev %s\n",
>> +                              class, dev_name(req_dev), dev_name(dev));
>> +             else
>> +                     pr_debug("OMAP PM: add constraint of class %d "
>> +                              "from req_dev %s on dev %s, t = %ld\n",
>> +                              class, dev_name(req_dev), dev_name(dev), t);
>> +
>> +             /* Call the omap_device API */
>> +             ret = omap_device_set_dev_constraint(class, req_dev, dev, t);
>> +     } else {
>> +             pr_err("OMAP-PM set_wakeup_lat: Error: platform device "
>> +                    "not valid\n");
>> +             return -EINVAL;
>> +     }
>>
>> -     return 0;
>> +     return ret;
>>  }
>>
>> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>> +/*
>> + * omap_pm_set_min_bus_tput - set/release bus throughput constraints
>> + */
>> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
>>  {
>>       if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
>>           agent_id != OCP_TARGET_AGENT)) {
>> @@ -68,83 +80,56 @@ int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>>               return -EINVAL;
>>       };
>>
>> -     if (r == 0)
>> -             pr_debug("OMAP PM: remove min bus tput constraint: "
>> -                      "dev %s for agent_id %d\n", dev_name(dev), agent_id);
>> -     else
>> -             pr_debug("OMAP PM: add min bus tput constraint: "
>> -                      "dev %s for agent_id %d: rate %ld KiB\n",
>> -                      dev_name(dev), agent_id, r);
>> -
>>       /*
>> -      * This code should model the interconnect and compute the
>> -      * required clock frequency, convert that to a VDD2 OPP ID, then
>> -      * set the VDD2 OPP appropriately.
>> -      *
>> -      * TI CDP code can call constraint_set here on the VDD2 OPP.
>> +      * This code calls the generic omap_device API function
>> +      * omap_pm_set_dev_constraint with the class
>> +      * OMAP_PM_CONSTRAINT_THROUGHPUT. omap_pm_set_dev_constraint
>> +      * should manage the constraints lists and call the appropriate
>> +      * low level code that models the interconnect, computes the required
>> +      * clock frequency, converts that to a VDD2 OPP ID and sets the
>> +      * VDD2 OPP appropriately.
>>        */
>> -
>> -     return 0;
>> +     return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_THROUGHPUT,
>> +                                       dev, dev, r);
>>  }
>>
>> +/*
>> + * omap_pm_set_max_dev_wakeup_lat - set/release devices wake-up latency
>> + * constraints
>> + */
>>  int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
>>                                  long t)
>>  {
>> -     if (!req_dev || !dev || t < -1) {
>> -             WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>> -             return -EINVAL;
>> -     };
>> -
>> -     if (t == -1)
>> -             pr_debug("OMAP PM: remove max device latency constraint: "
>> -                      "dev %s\n", dev_name(dev));
>> -     else
>> -             pr_debug("OMAP PM: add max device latency constraint: "
>> -                      "dev %s, t = %ld usec\n", dev_name(dev), t);
>> -
>> -     /*
>> -      * For current Linux, this needs to map the device to a
>> -      * powerdomain, then go through the list of current max lat
>> -      * constraints on that powerdomain and find the smallest.  If
>> -      * the latency constraint has changed, the code should
>> -      * recompute the state to enter for the next powerdomain
>> -      * state.  Conceivably, this code should also determine
>> -      * whether to actually disable the device clocks or not,
>> -      * depending on how long it takes to re-enable the clocks.
>> -      *
>> -      * TI CDP code can call constraint_set here.
>> -      */
>> -
>> -     return 0;
>> +     return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
>> +                                       req_dev, dev, t);
>>  }
>>
>> -int omap_pm_set_max_sdma_lat(struct device *dev, long t)
>> +/*
>> + * omap_pm_set_max_mpu_wakeup_lat - set/release MPU wake-up latency
>> + * constraints
>> + *
>> + * Maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
>> + * as constraint class and the MPU device as constraints target.
>> + */
>> +int omap_pm_set_max_mpu_wakeup_lat(struct device *req_dev, long t)
>>  {
>> -     if (!dev || t < -1) {
>> -             WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
>> -             return -EINVAL;
>> -     };
>> -
>> -     if (t == -1)
>> -             pr_debug("OMAP PM: remove max DMA latency constraint: "
>> -                      "dev %s\n", dev_name(dev));
>> -     else
>> -             pr_debug("OMAP PM: add max DMA latency constraint: "
>> -                      "dev %s, t = %ld usec\n", dev_name(dev), t);
>> -
>> -     /*
>> -      * For current Linux PM QOS params, this code should scan the
>> -      * list of maximum CPU and DMA latencies and select the
>> -      * smallest, then set cpu_dma_latency pm_qos_param
>> -      * accordingly.
>> -      *
>> -      * For future Linux PM QOS params, with separate CPU and DMA
>> -      * latency params, this code should just set the dma_latency param.
>> -      *
>> -      * TI CDP code can call constraint_set here.
>> -      */
>> +     return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
>> +                                       req_dev, omap2_get_mpuss_device(),
>> +                                       t);
>> +}
>>
>> -     return 0;
>> +/*
>> + * omap_pm_set_max_sdma_lat - set/release SDMA start latency
>> + * constraints
>> + *
>> + * Currently maps to omap_pm_set_dev_constraint with OMAP_PM_CONSTRAINT_WKUP_LAT
>> + * as constraint class and the L3 device as constraints target.
>> + */
>> +int omap_pm_set_max_sdma_lat(struct device *req_dev, long t)
>> +{
>> +     return omap_pm_set_dev_constraint(OMAP_PM_CONSTRAINT_WKUP_LAT,
>> +                                       req_dev, omap2_get_l3_device(),
>> +                                       t);
>>  }
>>
>>  int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
>> diff --git a/arch/arm/plat-omap/omap-pm-noop.c b/arch/arm/plat-omap/omap-pm-noop.c
>> index b0471bb2..7868edc 100644
>> --- a/arch/arm/plat-omap/omap-pm-noop.c
>> +++ b/arch/arm/plat-omap/omap-pm-noop.c
>> @@ -61,7 +61,7 @@ int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
>>       return 0;
>>  }
>>
>> -int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
>> +int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, long r)
>>  {
>>       if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
>>           agent_id != OCP_TARGET_AGENT)) {
>> diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
>> index 9bbda9a..b33b7fa 100644
>> --- a/arch/arm/plat-omap/omap_device.c
>> +++ b/arch/arm/plat-omap/omap_device.c
>> @@ -292,10 +292,189 @@ static void _add_optional_clock_clkdev(struct omap_device *od,
>>       }
>>  }
>>
>> +/* plist that stores the devices wake-up latency constraints */
>> +static struct plist_head omap_device_wkup_lat_constraints_list;
>> +/* Spinlock that protects the constraints lists */
>> +static spinlock_t omap_device_constraints_lock;
>> +/* Mutex that protects the constraints lists ops */
>> +static struct mutex omap_device_constraints_mutex;
>> +
>> +/*
>> + * omap_device_store_constraint: add/update/remove a constraint from a plist
>> + *
>> + * @constraints_list: plist to use
>> + * @req_dev: constraint requester, used to track the requests
>> + * @target: target which the constraint applies to (e.g. power domain ID or
>> + *  ptr for wake-up latency constraints)
>> + * @value: constraint value. The plist is sorted by the value. -1 remove the
>> + *  constraint from the list
>> + *
>> + * Returns the strongest constraint value for the given target, 0 in the
>> + * case there is no constraint on the given target or a negative value in
>> + * case of error.
>> + * The caller must check the validity of the parameters.
>> + */
>> +static long omap_device_store_constraint(struct plist_head *constraints_list,
>> +                                      struct device *req_dev, void *target,
>> +                                      long value)
>> +{
>> +     struct omap_device_constraints_entry *user;
>> +     int found = 0, ret = 0;
>> +
>> +     mutex_lock(&omap_device_constraints_mutex);
>> +
>> +     /* Check if the constraint requester is already in the list */
>> +     plist_for_each_entry(user, constraints_list, node) {
>> +             if (user->req_dev == req_dev) {
>> +                     found = 1;
>> +                     break;
>> +             }
>> +     }
>> +
>> +     if (value >= 0) {
>
> This should really be split into two functions, _add_constraint() and
> _remove_constraint().  You may wish to review Documentation/CodingStyle
> Chapter 6.
Cf. the remark above about it.
Yes the 80-characters rule is a real PITA. I am not using my
monochrome (amber) monitor anymore those days ;p

>
>> +             /* Add new entry to the list or update existing request */
>> +             if (found &&
>> +                 user->constraint_value == value &&
>> +                 user->target == target) {
>> +                     goto exit_ok;
>> +             } else if (!found) {
>> +                     user = kzalloc(
>> +                             sizeof(struct omap_device_constraints_entry),
>> +                             GFP_KERNEL);
>> +                     if (!user) {
>> +                             pr_err("%s: FATAL ERROR: kzalloc failed\n",
>> +                                    __func__);
>> +                             ret = -ENOMEM;
>> +                             goto exit_error;
>> +                     }
>> +                     user->req_dev = req_dev;
>> +             } else {
>> +                     plist_del(&user->node, constraints_list);
>> +             }
>> +
>> +             plist_node_init(&user->node, value);
>> +             plist_add(&user->node, constraints_list);
>> +             user->node.prio = user->constraint_value = value;
>> +             user->target = target;
>> +     } else {
>> +             /* Remove the constraint from the list */
>> +             if (!found) {
>> +                     pr_err("%s: Error: no prior constraint to release\n",
>> +                            __func__);
>> +                     ret = -EINVAL;
>> +                     goto exit_error;
>> +             }
>> +
>> +             plist_del(&user->node, constraints_list);
>> +             kfree(user);
>> +     }
>> +
>> +exit_ok:
>> +     /* Find the strongest constraint for the given target */
>> +     ret = 0;
>> +     plist_for_each_entry(user, constraints_list, node) {
>> +             if (user->target == target) {
>> +                     ret = user->constraint_value;
>> +                     break;
>> +             }
>> +     }
>> +
>> +exit_error:
>> +     mutex_unlock(&omap_device_constraints_mutex);
>> +
>> +     return ret;
>> +}
>>
>>  /* Public functions for use by core code */
>>
>>  /**
>> + * omap_device_set_max_dev_wakeup_lat - set/release a device constraint
>> + * @class: constraint class
>> + * @dev: device to apply the constraint to. Must have an associated omap_device
>> + * @req_dev: constraint requester, used for tracking the constraints
>> + *
>> + * Using the primary hwmod, set/release a device constraint for the dev
>> + * device, requested by the req_dev device. Depending of the constraint class
>> + * this code calls the appropriate low level code, e.g. power domain for
>> + * the wake-up latency constraints.
>> + *
>> + * If any hwmods exist for the omap_device assoiated with @dev and @req_dev,
>> + * set/release the constraint for the corresponding hwmods, otherwise return
>> + * -EINVAL.
>> + */
>> +int omap_device_set_dev_constraint(enum omap_pm_constraint_class class,
>> +                                struct device *req_dev,
>> +                                struct device *dev, long t)
>
> The name of this function doesn't match what's in the kerneldoc comment.
OK will update.

>
>> +{
>> +     struct omap_device *od;
>> +     struct omap_hwmod *oh;
>> +     struct platform_device *pdev;
>> +     struct powerdomain *pwrdm = NULL;
>> +     u32 ret = -EINVAL;
>> +
>> +     /* Look for the platform device for dev */
>> +     pdev = to_platform_device(dev);
>> +
>> +     /* Try to catch non platform devices. */
>> +     if (pdev->name == NULL) {
>> +             pr_err("%s: Error: platform device for device %s not valid\n",
>> +                    __func__, dev_name(dev));
>> +             return -EINVAL;
>> +     }
>> +
>> +     /* Find the associated omap_device for dev */
>> +     od = _find_by_pdev(pdev);
>> +     if (!(od->hwmods_cnt)) {
>> +             pr_err("%s: Error: No hwmod for device %s\n",
>> +                    __func__, dev_name(dev));
>> +             return -EINVAL;
>> +     }
>
> Please also pr_err() and bail out if there is more than one hwmod in the
> omap_device.
Ok. IIUC nothing should be done in case of more than one hwmod per od?
Is that a realistic situation?

>
>> +
>> +     /* Find the associated omap_hwmod for dev */
>> +     oh = od->hwmods[0];
>> +
>> +     switch (class) {
>> +     case OMAP_PM_CONSTRAINT_WKUP_LAT:
>
> Please create two different functions,
> omap_device_set_max_dev_wakeup_lat() and
> omap_device_set_min_bus_tput().  Documentation/CodingStyle chapter 6.
It has been agreed (in weekly calls) to have two functions at the OMAP
PM level but only one function with a class parameter at the
omap_device level. This allows easier maintenance and clean-up later.
Kevin, is that corrcet?

>
>> +             /* Find the pwrdm associated to dev */
>> +             pwrdm = omap_device_get_pwrdm(od);
>> +             if (!pwrdm) {
>> +                     pr_err("%s: Error: No pwrdm for device %s\n",
>> +                            __func__, dev_name(dev));
>> +                     ret = -EINVAL;
>> +                     break;
>> +             }
>> +
>> +             /*
>> +              * Store the constraint in the appropriate list and find the
>> +              * strongest constraint for the given pwrdm
>> +              */
>> +             ret = omap_device_store_constraint(
>> +                                     &omap_device_wkup_lat_constraints_list,
>> +                                     req_dev, (void *) pwrdm, t);
>> +
>> +             /* Apply the constraint to the corresponding pwrdm */
>> +             if (ret >= 0) {
>> +                     ret = omap_hwmod_update_power_state(oh, ret);
>> +             } else {
>> +                     pr_err("%s: Error storing the constraint for device "
>> +                            "%s\n", __func__, dev_name(dev));
>> +             }
>> +
>> +             break;
>> +     case OMAP_PM_CONSTRAINT_THROUGHPUT:
>> +             WARN(1, "OMAP PM: %s: Bus throughput constraint class \
>> +                  not implemented\n", __func__);
>> +             ret = -EINVAL;
>> +             break;
>> +     default:
>> +             WARN(1, "OMAP PM: %s: invalid constraint class %d",
>> +                  __func__, class);
>> +     }
>> +
>> +     return ret;
>> +}
>> +
>> +/**
>>   * omap_device_get_context_loss_count - get lost context count
>>   * @od: struct omap_device *
>>   *
>> @@ -824,6 +1003,14 @@ struct device omap_device_parent = {
>>
>>  static int __init omap_device_init(void)
>>  {
>> +     /* Initialize priority ordered list for wakeup latency constraint */
>> +     spin_lock_init(&omap_device_constraints_lock);
>> +     plist_head_init(&omap_device_wkup_lat_constraints_list,
>> +                     &omap_device_constraints_lock);
>> +
>> +     /* res_mutex protects res_list add and del ops */
>> +     mutex_init(&omap_device_constraints_mutex);
>> +
>>       return device_register(&omap_device_parent);
>>  }
>>  core_initcall(omap_device_init);
>> --
>> 1.7.2.3
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
>
> - Paul
>

Thanks!
Jean
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Re: [PATCH 2/2] OMAP: PM: implement devices constraints APIs

[Kevin Hilman]

Jean Pihet <jean.pihet@newoldbits.com> writes:

[...]
>> Please create two different functions,
>> omap_device_set_max_dev_wakeup_lat() and
>> omap_device_set_min_bus_tput().  Documentation/CodingStyle chapter 6.
>>

> It has been agreed (in weekly calls) to have two functions at the OMAP
> PM level but only one function with a class parameter at the
> omap_device level. This allows easier maintenance and clean-up later.
> Kevin, is that corrcet?

Yes, that is my preference (but Paul is the maintainer of these layers,
so he has the final say.)  What I would like to see is a more generic
API at the omap_device level which can easily be extended to handle new
constraints (by adding a new 'class'), without having to grow the API
each time.

That being said, you can still create the two functions that Paul
mentioned above and just have the generic function call those based on
class.

The only question then is which interface the drivers will eventually
use.  I much prefer keeping the driver interface to a simple set of add
& remove constraint functions where the type is determined by class:

Today we have:

 - max wakeup latency
 - min bus througput

but eventually we may also want

 - min frequency
 - max frequency (thermal)
 - etc.

Kevin
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[RFC PATCH 0/2] OMAP: PM: add devices wakeup latency constraints APIs

[jean.pihet]

From: Jean Pihet <j-pihet@ti.com>

- Implement OMAP PM layer omap_pm_set_max_dev_wakeup_lat API.
- Created arch/arm/plat-omap/omap-pm-constraints.c file from 
arch/arm/plat-omap/omap-pm-noop.c and the associated Kconfig option
OMAP_PM_CONSTRAINTS.

This code is an early submission in RFC state and is for review only.
Testing is on-going.

ToDo:
- implement the API for the SDMA device (omap_pm_set_max_sdma_lat),
- change the power domains latency figures to some more realistic values,
- add the hook to the existing kernel PM QoS interfaces (cpu_dma_latency),
   cf. Documentation/power/pm_qos_interface.txt

Jean Pihet (2):
  OMAP PM: create a PM layer plugin for the devices wakeup latency
    constraints
  OMAP: PM: implement devices wakeup latency constraints APIs

 arch/arm/mach-omap2/omap_hwmod.c              |   62 +++++-
 arch/arm/mach-omap2/powerdomain.c             |  176 +++++++++++++-
 arch/arm/mach-omap2/powerdomain.h             |   31 +++
 arch/arm/mach-omap2/powerdomains3xxx_data.c   |   60 +++++
 arch/arm/plat-omap/Kconfig                    |    7 +
 arch/arm/plat-omap/Makefile                   |    1 +
 arch/arm/plat-omap/include/plat/omap_device.h |    2 +
 arch/arm/plat-omap/include/plat/omap_hwmod.h  |    2 +
 arch/arm/plat-omap/omap-pm-constraints.c      |  344 +++++++++++++++++++++++++
 arch/arm/plat-omap/omap_device.c              |   28 ++
 10 files changed, 710 insertions(+), 3 deletions(-)
 create mode 100644 arch/arm/plat-omap/omap-pm-constraints.c

-- 
1.7.2.3

[PATCH 1/2] OMAP PM: create a PM layer plugin for the devices wakeup latency constraints

[jean.pihet]

From: Jean Pihet <j-pihet@ti.com>

Created arch/arm/plat-omap/omap-pm-constraints.c file from
arch/arm/plat-omap/omap-pm-noop.c and the associated Kconfig option
OMAP_PM_CONSTRAINTS.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
---
 arch/arm/plat-omap/Kconfig               |    7 +
 arch/arm/plat-omap/Makefile              |    1 +
 arch/arm/plat-omap/omap-pm-constraints.c |  363 ++++++++++++++++++++++++++++++
 3 files changed, 371 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/plat-omap/omap-pm-constraints.c

diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
index b6333ae..b8f51e3 100644
--- a/arch/arm/plat-omap/Kconfig
+++ b/arch/arm/plat-omap/Kconfig
@@ -215,6 +215,13 @@ config OMAP_PM_NONE
 config OMAP_PM_NOOP
 	bool "No-op/debug PM layer"
 
+config OMAP_PM_CONSTRAINTS
+	depends on PM
+	bool "OMAP PM layer implementation, devices wakeup latency constraints"
+	help
+	  Select this option to enable the PM layer plugin for
+	  the devices wakeup latency constraints support
+
 endchoice
 
 endmenu
diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile
index a4a1285..a293367 100644
--- a/arch/arm/plat-omap/Makefile
+++ b/arch/arm/plat-omap/Makefile
@@ -32,3 +32,4 @@ obj-y += $(i2c-omap-m) $(i2c-omap-y)
 obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o
 
 obj-$(CONFIG_OMAP_PM_NOOP) += omap-pm-noop.o
+obj-$(CONFIG_OMAP_PM_CONSTRAINTS) += omap-pm-constraints.o
diff --git a/arch/arm/plat-omap/omap-pm-constraints.c b/arch/arm/plat-omap/omap-pm-constraints.c
new file mode 100644
index 0000000..c8b4e4c
--- /dev/null
+++ b/arch/arm/plat-omap/omap-pm-constraints.c
@@ -0,0 +1,363 @@
+/*
+ * omap-pm.c - OMAP power management interface
+ *
+ * This code implements the OMAP power management interface to
+ * drivers, CPUIdle, CPUFreq, and DSP Bridge.
+ *
+ * Copyright (C) 2008-2009 Texas Instruments, Inc.
+ * Copyright (C) 2008-2009 Nokia Corporation
+ * Paul Walmsley
+ *
+ * Interface developed by (in alphabetical order):
+ * Karthik Dasu, Tony Lindgren, Jean Pihet, Rajendra Nayak, Sakari Poussa,
+ * Veeramanikandan Raju, Anand Sawant, Igor Stoppa, Paul Walmsley,
+ * Richard Woodruff
+ */
+
+#undef DEBUG
+
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+
+/* Interface documentation is in mach/omap-pm.h */
+#include <plat/omap-pm.h>
+#include <plat/omap_device.h>
+
+static bool off_mode_enabled;
+static u32 dummy_context_loss_counter;
+
+/*
+ * Device-driver-originated constraints (via board-*.c files)
+ */
+
+int omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
+{
+	if (!dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (t == -1)
+		pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+
+	/*
+	 * For current Linux, this needs to map the MPU to a
+	 * powerdomain, then go through the list of current max lat
+	 * constraints on the MPU and find the smallest.  If
+	 * the latency constraint has changed, the code should
+	 * recompute the state to enter for the next powerdomain
+	 * state.
+	 *
+	 * TI CDP code can call constraint_set here.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
+{
+	if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
+	    agent_id != OCP_TARGET_AGENT)) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (r == 0)
+		pr_debug("OMAP PM: remove min bus tput constraint: "
+			 "dev %s for agent_id %d\n", dev_name(dev), agent_id);
+	else
+		pr_debug("OMAP PM: add min bus tput constraint: "
+			 "dev %s for agent_id %d: rate %ld KiB\n",
+			 dev_name(dev), agent_id, r);
+
+	/*
+	 * This code should model the interconnect and compute the
+	 * required clock frequency, convert that to a VDD2 OPP ID, then
+	 * set the VDD2 OPP appropriately.
+	 *
+	 * TI CDP code can call constraint_set here on the VDD2 OPP.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_max_dev_wakeup_lat(struct device *req_dev, struct device *dev,
+				   long t)
+{
+	if (!req_dev || !dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (t == -1)
+		pr_debug("OMAP PM: remove max device latency constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add max device latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+
+	/*
+	 * For current Linux, this needs to map the device to a
+	 * powerdomain, then go through the list of current max lat
+	 * constraints on that powerdomain and find the smallest.  If
+	 * the latency constraint has changed, the code should
+	 * recompute the state to enter for the next powerdomain
+	 * state.  Conceivably, this code should also determine
+	 * whether to actually disable the device clocks or not,
+	 * depending on how long it takes to re-enable the clocks.
+	 *
+	 * TI CDP code can call constraint_set here.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_max_sdma_lat(struct device *dev, long t)
+{
+	if (!dev || t < -1) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	};
+
+	if (t == -1)
+		pr_debug("OMAP PM: remove max DMA latency constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add max DMA latency constraint: "
+			 "dev %s, t = %ld usec\n", dev_name(dev), t);
+
+	/*
+	 * For current Linux PM QOS params, this code should scan the
+	 * list of maximum CPU and DMA latencies and select the
+	 * smallest, then set cpu_dma_latency pm_qos_param
+	 * accordingly.
+	 *
+	 * For future Linux PM QOS params, with separate CPU and DMA
+	 * latency params, this code should just set the dma_latency param.
+	 *
+	 * TI CDP code can call constraint_set here.
+	 */
+
+	return 0;
+}
+
+int omap_pm_set_min_clk_rate(struct device *dev, struct clk *c, long r)
+{
+	if (!dev || !c || r < 0) {
+		WARN(1, "OMAP PM: %s: invalid parameter(s)", __func__);
+		return -EINVAL;
+	}
+
+	if (r == 0)
+		pr_debug("OMAP PM: remove min clk rate constraint: "
+			 "dev %s\n", dev_name(dev));
+	else
+		pr_debug("OMAP PM: add min clk rate constraint: "
+			 "dev %s, rate = %ld Hz\n", dev_name(dev), r);
+
+	/*
+	 * Code in a real implementation should keep track of these
+	 * constraints on the clock, and determine the highest minimum
+	 * clock rate.  It should iterate over each OPP and determine
+	 * whether the OPP will result in a clock rate that would
+	 * satisfy this constraint (and any other PM constraint in effect
+	 * at that time).  Once it finds the lowest-voltage OPP that
+	 * meets those conditions, it should switch to it, or return
+	 * an error if the code is not capable of doing so.
+	 */
+
+	return 0;
+}
+
+/*
+ * DSP Bridge-specific constraints
+ */
+
+const struct omap_opp *omap_pm_dsp_get_opp_table(void)
+{
+	pr_debug("OMAP PM: DSP request for OPP table\n");
+
+	/*
+	 * Return DSP frequency table here:  The final item in the
+	 * array should have .rate = .opp_id = 0.
+	 */
+
+	return NULL;
+}
+
+void omap_pm_dsp_set_min_opp(u8 opp_id)
+{
+	if (opp_id == 0) {
+		WARN_ON(1);
+		return;
+	}
+
+	pr_debug("OMAP PM: DSP requests minimum VDD1 OPP to be %d\n", opp_id);
+
+	/*
+	 *
+	 * For l-o dev tree, our VDD1 clk is keyed on OPP ID, so we
+	 * can just test to see which is higher, the CPU's desired OPP
+	 * ID or the DSP's desired OPP ID, and use whichever is
+	 * highest.
+	 *
+	 * In CDP12.14+, the VDD1 OPP custom clock that controls the DSP
+	 * rate is keyed on MPU speed, not the OPP ID.  So we need to
+	 * map the OPP ID to the MPU speed for use with clk_set_rate()
+	 * if it is higher than the current OPP clock rate.
+	 *
+	 */
+}
+
+
+u8 omap_pm_dsp_get_opp(void)
+{
+	pr_debug("OMAP PM: DSP requests current DSP OPP ID\n");
+
+	/*
+	 * For l-o dev tree, call clk_get_rate() on VDD1 OPP clock
+	 *
+	 * CDP12.14+:
+	 * Call clk_get_rate() on the OPP custom clock, map that to an
+	 * OPP ID using the tables defined in board-*.c/chip-*.c files.
+	 */
+
+	return 0;
+}
+
+/*
+ * CPUFreq-originated constraint
+ *
+ * In the future, this should be handled by custom OPP clocktype
+ * functions.
+ */
+
+struct cpufreq_frequency_table **omap_pm_cpu_get_freq_table(void)
+{
+	pr_debug("OMAP PM: CPUFreq request for frequency table\n");
+
+	/*
+	 * Return CPUFreq frequency table here: loop over
+	 * all VDD1 clkrates, pull out the mpu_ck frequencies, build
+	 * table
+	 */
+
+	return NULL;
+}
+
+void omap_pm_cpu_set_freq(unsigned long f)
+{
+	if (f == 0) {
+		WARN_ON(1);
+		return;
+	}
+
+	pr_debug("OMAP PM: CPUFreq requests CPU frequency to be set to %lu\n",
+		 f);
+
+	/*
+	 * For l-o dev tree, determine whether MPU freq or DSP OPP id
+	 * freq is higher.  Find the OPP ID corresponding to the
+	 * higher frequency.  Call clk_round_rate() and clk_set_rate()
+	 * on the OPP custom clock.
+	 *
+	 * CDP should just be able to set the VDD1 OPP clock rate here.
+	 */
+}
+
+unsigned long omap_pm_cpu_get_freq(void)
+{
+	pr_debug("OMAP PM: CPUFreq requests current CPU frequency\n");
+
+	/*
+	 * Call clk_get_rate() on the mpu_ck.
+	 */
+
+	return 0;
+}
+
+/**
+ * omap_pm_enable_off_mode - notify OMAP PM that off-mode is enabled
+ *
+ * Intended for use only by OMAP PM core code to notify this layer
+ * that off mode has been enabled.
+ */
+void omap_pm_enable_off_mode(void)
+{
+	off_mode_enabled = true;
+}
+
+/**
+ * omap_pm_disable_off_mode - notify OMAP PM that off-mode is disabled
+ *
+ * Intended for use only by OMAP PM core code to notify this layer
+ * that off mode has been disabled.
+ */
+void omap_pm_disable_off_mode(void)
+{
+	off_mode_enabled = false;
+}
+
+/*
+ * Device context loss tracking
+ */
+
+#ifdef CONFIG_ARCH_OMAP2PLUS
+
+u32 omap_pm_get_dev_context_loss_count(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	u32 count;
+
+	if (WARN_ON(!dev))
+		return 0;
+
+	if (dev->parent == &omap_device_parent) {
+		count = omap_device_get_context_loss_count(pdev);
+	} else {
+		WARN_ONCE(off_mode_enabled, "omap_pm: using dummy context "
+			  "loss counter; device %s should be converted to "
+			  "omap_device", dev_name(dev));
+		if (off_mode_enabled)
+			dummy_context_loss_counter++;
+		count = dummy_context_loss_counter;
+	}
+
+	pr_debug("OMAP PM: context loss count for dev %s = %d\n",
+		 dev_name(dev), count);
+
+	return count;
+}
+
+#else
+
+u32 omap_pm_get_dev_context_loss_count(struct device *dev)
+{
+	return dummy_context_loss_counter;
+}
+
+#endif
+
+/* Should be called before clk framework init */
+int __init omap_pm_if_early_init(void)
+{
+	return 0;
+}
+
+/* Must be called after clock framework is initialized */
+int __init omap_pm_if_init(void)
+{
+	return 0;
+}
+
+void omap_pm_if_exit(void)
+{
+	/* Deallocate CPUFreq frequency table here */
+}
+
-- 
1.7.2.3