[PATCH v2 0/9] powerpc/powernv/cpuidle: Add support for POWER ISA v3 idle states

[PATCH v2 0/9] powerpc/powernv/cpuidle: Add support for POWER ISA v3 idle states

[Shreyas B. Prabhu]

POWER ISA v3 defines a new idle processor core mechanism. In summary,
 a) new instruction named stop is added. This instruction replaces
	instructions like nap, sleep, rvwinkle.
 b) new per thread SPR named PSSCR is added which controls the behavior
	of stop instruction. 
		
PSSCR has following key fields
	Bits 0:3  - Power-Saving Level Status. This field indicates the
	lowest power-saving state the thread entered since stop
	instruction was last executed.
		
	Bit 42 - Enable State Loss                          
	0 - No state is lost irrespective of other fields  
	1 - Allows state loss
		
	Bits 44:47 - Power-Saving Level Limit      
	This limits the power-saving level that can be entered into.
		
	Bits 60:63 - Requested Level              
	Used to specify which power-saving level must be entered on
	executing stop instruction
		
Stop idle states and their properties like name, latency, target
residency, psscr value are exposed via device tree.

This patch series adds support for this new mechanism.

Patches 1-6 are cleanups and code movement.
Patch 7 adds platform specific support for stop and psscr handling.
Patch 8 adds cpuidle driver support.
Patch 9 makes offlined cpu use stop state.

Changes in v2
=============
 - Rebased on v4.6-rc6
 - Using CPU_FTR_ARCH_300 bit instead of CPU_FTR_STOP_INST

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Michael Neuling <mikey@neuling.org>
Cc: linuxppc-dev@lists.ozlabs.org


Shreyas B. Prabhu (9):
  powerpc/powernv: Move CHECK_HMI_INTERRUPT to exception-64s header
  powerpc/kvm: make hypervisor state restore a function
  powerpc/powernv: Move idle code usable by multiple hardware to common
    location
  powerpc/powernv: Make power7_powersave_common more generic
  powerpc/powernv: Move idle related macros to cpuidle.h
  powerpc/powernv: set power_save func after the idle states are
    initialized
  powerpc/powernv: Add platform support for stop instruction
  cpuidle/powernv: Add support for POWER ISA v3 idle states
  powerpc/powernv: Use deepest stop state when cpu is offlined

 arch/powerpc/include/asm/cpuidle.h        |  29 ++++
 arch/powerpc/include/asm/exception-64s.h  |  18 +++
 arch/powerpc/include/asm/kvm_book3s_asm.h |   2 +-
 arch/powerpc/include/asm/machdep.h        |   1 +
 arch/powerpc/include/asm/opal-api.h       |  11 +-
 arch/powerpc/include/asm/paca.h           |   4 +
 arch/powerpc/include/asm/ppc-opcode.h     |   4 +
 arch/powerpc/include/asm/processor.h      |   1 +
 arch/powerpc/include/asm/reg.h            |  11 ++
 arch/powerpc/kernel/Makefile              |   2 +
 arch/powerpc/kernel/asm-offsets.c         |   4 +
 arch/powerpc/kernel/exceptions-64s.S      |  29 +---
 arch/powerpc/kernel/idle_power7.S         | 212 +++-------------------------
 arch/powerpc/kernel/idle_power_common.S   | 185 +++++++++++++++++++++++++
 arch/powerpc/kernel/idle_power_stop.S     | 221 ++++++++++++++++++++++++++++++
 arch/powerpc/platforms/Kconfig            |   4 +
 arch/powerpc/platforms/powernv/Kconfig    |   1 +
 arch/powerpc/platforms/powernv/idle.c     |  94 +++++++++++--
 arch/powerpc/platforms/powernv/powernv.h  |   1 +
 arch/powerpc/platforms/powernv/setup.c    |   2 +-
 arch/powerpc/platforms/powernv/smp.c      |   4 +-
 drivers/cpuidle/cpuidle-powernv.c         |  57 +++++++-
 22 files changed, 659 insertions(+), 238 deletions(-)
 create mode 100644 arch/powerpc/kernel/idle_power_common.S
 create mode 100644 arch/powerpc/kernel/idle_power_stop.S

-- 
2.4.11

[PATCH v2 8/9] cpuidle/powernv: Add support for POWER ISA v3 idle states

[Shreyas B. Prabhu]

POWER ISA v3 defines a new idle processor core mechanism. In summary,
 a) new instruction named stop is added.
 b) new per thread SPR named PSSCR is added which controls the behavior
	of stop instruction.

Supported idle states and value to be written to PSSCR register to enter
any idle state is exposed via ibm,cpu-idle-state-names and
ibm,cpu-idle-state-psscr respectively. To enter an idle state,
platform provided power_stop() needs to be invoked with the appropriate
PSSCR value.

This patch adds support for this new mechanism in cpuidle powernv driver.

Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
---
 drivers/cpuidle/cpuidle-powernv.c | 57 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index e12dc30..efe5221 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -21,6 +21,7 @@
 #include <asm/runlatch.h>
 
 #define MAX_POWERNV_IDLE_STATES	8
+#define MAX_IDLE_STATE_NAME_LEN	10
 
 struct cpuidle_driver powernv_idle_driver = {
 	.name             = "powernv_idle",
@@ -29,9 +30,11 @@ struct cpuidle_driver powernv_idle_driver = {
 
 static int max_idle_state;
 static struct cpuidle_state *cpuidle_state_table;
+
+static u64 stop_psscr_table[MAX_POWERNV_IDLE_STATES];
+
 static u64 snooze_timeout;
 static bool snooze_timeout_en;
-
 static int snooze_loop(struct cpuidle_device *dev,
 			struct cpuidle_driver *drv,
 			int index)
@@ -139,6 +142,15 @@ static struct notifier_block setup_hotplug_notifier = {
 	.notifier_call = powernv_cpuidle_add_cpu_notifier,
 };
 
+static int stop_loop(struct cpuidle_device *dev,
+			struct cpuidle_driver *drv,
+			int index)
+{
+	ppc64_runlatch_off();
+	power_stop(stop_psscr_table[index]);
+	ppc64_runlatch_on();
+	return index;
+}
 /*
  * powernv_cpuidle_driver_init()
  */
@@ -169,6 +181,8 @@ static int powernv_add_idle_states(void)
 	int nr_idle_states = 1; /* Snooze */
 	int dt_idle_states;
 	u32 *latency_ns, *residency_ns, *flags;
+	u64 *psscr_val = NULL;
+	const char *names[MAX_POWERNV_IDLE_STATES];
 	int i, rc;
 
 	/* Currently we have snooze statically defined */
@@ -201,6 +215,23 @@ static int powernv_add_idle_states(void)
 		goto out_free_latency;
 	}
 
+	rc = of_property_read_string_array(power_mgt,
+		"ibm,cpu-idle-state-names", names, dt_idle_states);
+	if (rc < -1) {
+		pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-names in DT\n");
+		goto out_free_latency;
+	}
+
+	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+		psscr_val = kcalloc(dt_idle_states, sizeof(*psscr_val),
+					GFP_KERNEL);
+		rc = of_property_read_u64_array(power_mgt,
+			"ibm,cpu-idle-state-psscr", psscr_val, dt_idle_states);
+		if (rc < -1) {
+			pr_warn("cpuidle-powernv: missing ibm,cpu-idle-states-psscr in DT\n");
+			goto out_free_psscr;
+		}
+	}
 	residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
 	rc = of_property_read_u32_array(power_mgt,
 		"ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
@@ -218,6 +249,16 @@ static int powernv_add_idle_states(void)
 			powernv_states[nr_idle_states].flags = 0;
 			powernv_states[nr_idle_states].target_residency = 100;
 			powernv_states[nr_idle_states].enter = &nap_loop;
+		} else if ((flags[i] & OPAL_PM_STOP_INST_FAST) &&
+				!(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
+			strncpy(powernv_states[nr_idle_states].name,
+				(char *)names[i], MAX_IDLE_STATE_NAME_LEN);
+			strncpy(powernv_states[nr_idle_states].desc,
+				(char *)names[i], MAX_IDLE_STATE_NAME_LEN);
+			powernv_states[nr_idle_states].flags = 0;
+
+			powernv_states[nr_idle_states].enter = &stop_loop;
+			stop_psscr_table[nr_idle_states] = psscr_val[i];
 		}
 
 		/*
@@ -233,6 +274,18 @@ static int powernv_add_idle_states(void)
 			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
 			powernv_states[nr_idle_states].target_residency = 300000;
 			powernv_states[nr_idle_states].enter = &fastsleep_loop;
+		} else if ((flags[i] & OPAL_PM_STOP_INST_DEEP) &&
+				(flags[i] & OPAL_PM_TIMEBASE_STOP)) {
+
+			strncpy(powernv_states[nr_idle_states].name,
+				(char *)names[i], MAX_IDLE_STATE_NAME_LEN);
+			strncpy(powernv_states[nr_idle_states].desc,
+				(char *)names[i], MAX_IDLE_STATE_NAME_LEN);
+
+			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
+
+			powernv_states[nr_idle_states].enter = &stop_loop;
+			stop_psscr_table[nr_idle_states] = psscr_val[i];
 		}
 #endif
 		powernv_states[nr_idle_states].exit_latency =
@@ -247,6 +300,8 @@ static int powernv_add_idle_states(void)
 	}
 
 	kfree(residency_ns);
+out_free_psscr:
+	kfree(psscr_val);
 out_free_latency:
 	kfree(latency_ns);
 out_free_flags:
-- 
2.4.11