[RFC PATCH v3 0/4] cpuidle: (POWER) cpuidle driver for pSeries

[RFC PATCH v3 0/4] cpuidle: (POWER) cpuidle driver for pSeries

[Deepthi Dharwar]

This patch series ports the cpuidle framework for ppc64 platform and
implements a cpuidle back-end driver for ppc64 (pSeries) platform.
Currently idle states are managed by pseries_{dedicated,shared}_idle_sleep()
routines in arch/powerpc/platforms/pseries/setup.c.  There are
two idle states (snooze and cede) that are exploited by
these routines based on simple heuristics.

Moving the idle states over to cpuidle framework can take advantage of
the advanced heuristics, tunables, and features provided by cpuidle
framework. Additional idle states like extended cede with hints would be
included and exploited using the cpuidle framework. The statistics and 
tracing infrastructure provided by the cpuidle framework also helps in 
enabling power management related tools and help tune the system and 
applications.

This series aims to maintain compatibility and functionality to
existing pSeries idle cpu management code.  There are no new functions
or idle states added as part of this series.

The previous version of this patch can be found at
https://lkml.org/lkml/2011/11/17/127

Changes from the previous version (v2):

	1] Rebased to latest 3.2-rc3

	2] Incorporated the changes from the feedback provided by Ben
	   in the previous version of this series.

This patch series includes:

[1/4] - Provides arch specific cpu_idle_wait() function required by cpuidle
  subsystem.
[2/4] - pseries_idle cpuidle driver
[3/4] - Enables cpuidle for pSeries and directly calls cpuidle_idle_call()
[4/4] - Handles powersave=off kernel boot parameter and disables registration
  of pseries_idle cpuidle driver.

This series has been tested on ppc64 pSeries POWER7 system with the snooze
and cede states

--

 arch/powerpc/Kconfig                            |    4 
 arch/powerpc/include/asm/processor.h            |    3 
 arch/powerpc/include/asm/system.h               |    9 +
 arch/powerpc/kernel/idle.c                      |   27 ++
 arch/powerpc/kernel/sysfs.c                     |    2 
 arch/powerpc/platforms/Kconfig                  |    6 
 arch/powerpc/platforms/pseries/Kconfig          |    9 +
 arch/powerpc/platforms/pseries/Makefile         |    1 
 arch/powerpc/platforms/pseries/processor_idle.c |  329 +++++++++++++++++++++++
 arch/powerpc/platforms/pseries/pseries.h        |    3 
 arch/powerpc/platforms/pseries/setup.c          |  104 +------
 arch/powerpc/platforms/pseries/smp.c            |    1 
 include/linux/cpuidle.h                         |    2 
 13 files changed, 411 insertions(+), 89 deletions(-)
 create mode 100644 arch/powerpc/platforms/pseries/processor_idle.c



-Deepthi 

[RFC PATCH v3 1/4] cpuidle: (powerpc) Add cpu_idle_wait() to allow switching of idle routines

[Deepthi Dharwar]

This patch provides cpu_idle_wait() routine for the powerpc
platform which is required by the cpuidle subsystem. This
routine is required to change the idle handler on SMP systems.
The equivalent routine for x86 is in arch/x86/kernel/process.c
but the powerpc implementation is different.

cpuidle_disable variable is to enable/disable cpuidle
framework if power_save option is set during the boot
time.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: Arun R Bharadwaj <arun.r.bharadwaj@gmail.com>
---
 arch/powerpc/Kconfig                 |    4 ++++
 arch/powerpc/include/asm/processor.h |    2 ++
 arch/powerpc/include/asm/system.h    |    1 +
 arch/powerpc/kernel/idle.c           |   27 +++++++++++++++++++++++++++
 4 files changed, 34 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 951e18f..beeeec7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -87,6 +87,10 @@ config ARCH_HAS_ILOG2_U64
 	bool
 	default y if 64BIT
 
+config ARCH_HAS_CPU_IDLE_WAIT
+	bool
+	default y
+
 config GENERIC_HWEIGHT
 	bool
 	default y
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index eb11a44..811b7e7 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -382,6 +382,8 @@ static inline unsigned long get_clean_sp(struct pt_regs *regs, int is_32)
 }
 #endif
 
+enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
+
 #endif /* __KERNEL__ */
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_PROCESSOR_H */
diff --git a/arch/powerpc/include/asm/system.h b/arch/powerpc/include/asm/system.h
index e30a13d..ff66680 100644
--- a/arch/powerpc/include/asm/system.h
+++ b/arch/powerpc/include/asm/system.h
@@ -221,6 +221,7 @@ extern unsigned long klimit;
 extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
 
 extern int powersave_nap;	/* set if nap mode can be used in idle loop */
+void cpu_idle_wait(void);
 
 /*
  * Atomic exchange
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 39a2baa..8574b0e 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -39,9 +39,13 @@
 #define cpu_should_die()	0
 #endif
 
+unsigned long cpuidle_disable = IDLE_NO_OVERRIDE;
+EXPORT_SYMBOL(cpuidle_disable);
+
 static int __init powersave_off(char *arg)
 {
 	ppc_md.power_save = NULL;
+	cpuidle_disable = IDLE_POWERSAVE_OFF;
 	return 0;
 }
 __setup("powersave=off", powersave_off);
@@ -102,6 +106,29 @@ void cpu_idle(void)
 	}
 }
 
+
+/*
+ * cpu_idle_wait - Used to ensure that all the CPUs come out of the old
+ * idle loop and start using the new idle loop.
+ * Required while changing idle handler on SMP systems.
+ * Caller must have changed idle handler to the new value before the call.
+ * This window may be larger on shared systems.
+ */
+void cpu_idle_wait(void)
+{
+	int cpu;
+	smp_mb();
+
+	/* kick all the CPUs so that they exit out of old idle routine */
+	get_online_cpus();
+	for_each_online_cpu(cpu) {
+		if (cpu != smp_processor_id())
+			smp_send_reschedule(cpu);
+	}
+	put_online_cpus();
+}
+EXPORT_SYMBOL_GPL(cpu_idle_wait);
+
 int powersave_nap;
 
 #ifdef CONFIG_SYSCTL

[RFC PATCH v3 2/4] cpuidle: (POWER) cpuidle driver for pSeries

[Deepthi Dharwar]

This patch implements a back-end cpuidle driver for pSeries
based on pseries_dedicated_idle_loop and pseries_shared_idle_loop
routines.  The driver is built only if CONFIG_CPU_IDLE is set. This
cpuidle driver uses global registration of idle states and
not per-cpu.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: Arun R Bharadwaj <arun.r.bharadwaj@gmail.com>
---
 arch/powerpc/include/asm/system.h               |    8 +
 arch/powerpc/kernel/sysfs.c                     |    2 
 arch/powerpc/platforms/pseries/Kconfig          |    9 +
 arch/powerpc/platforms/pseries/Makefile         |    1 
 arch/powerpc/platforms/pseries/processor_idle.c |  326 +++++++++++++++++++++++
 arch/powerpc/platforms/pseries/pseries.h        |    3 
 arch/powerpc/platforms/pseries/setup.c          |    3 
 arch/powerpc/platforms/pseries/smp.c            |    1 
 8 files changed, 350 insertions(+), 3 deletions(-)
 create mode 100644 arch/powerpc/platforms/pseries/processor_idle.c

diff --git a/arch/powerpc/include/asm/system.h b/arch/powerpc/include/asm/system.h
index ff66680..f56a0a7 100644
--- a/arch/powerpc/include/asm/system.h
+++ b/arch/powerpc/include/asm/system.h
@@ -223,6 +223,14 @@ extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
 extern int powersave_nap;	/* set if nap mode can be used in idle loop */
 void cpu_idle_wait(void);
 
+#ifdef CONFIG_PSERIES_IDLE
+extern void update_smt_snooze_delay(int snooze);
+extern int pseries_notify_cpuidle_add_cpu(int cpu);
+#else
+static inline void update_smt_snooze_delay(int snooze) {}
+static inline int pseries_notify_cpuidle_add_cpu(int cpu) { return 0; }
+#endif
+
 /*
  * Atomic exchange
  *
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index ce035c1..ebe5d78 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -18,6 +18,7 @@
 #include <asm/machdep.h>
 #include <asm/smp.h>
 #include <asm/pmc.h>
+#include <asm/system.h>
 
 #include "cacheinfo.h"
 
@@ -51,6 +52,7 @@ static ssize_t store_smt_snooze_delay(struct sys_device *dev,
 		return -EINVAL;
 
 	per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
+	update_smt_snooze_delay(snooze);
 
 	return count;
 }
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index c81f6bb..ae7b6d4 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -120,3 +120,12 @@ config DTL
 	  which are accessible through a debugfs file.
 
 	  Say N if you are unsure.
+
+config PSERIES_IDLE
+	tristate "Cpuidle driver for pSeries platforms"
+	depends on CPU_IDLE
+	depends on PPC_PSERIES
+	default y
+	help
+	  Select this option to enable processor idle state management
+	  through cpuidle subsystem.
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 3556e40..236db46 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_PHYP_DUMP)		+= phyp_dump.o
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_DTL)		+= dtl.o
 obj-$(CONFIG_IO_EVENT_IRQ)	+= io_event_irq.o
+obj-$(CONFIG_PSERIES_IDLE)	+= processor_idle.o
 
 ifeq ($(CONFIG_PPC_PSERIES),y)
 obj-$(CONFIG_SUSPEND)		+= suspend.o
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
new file mode 100644
index 0000000..352b78a
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/processor_idle.c
@@ -0,0 +1,326 @@
+/*
+ *  processor_idle - idle state cpuidle driver.
+ *  Adapted from drivers/idle/intel_idle.c and
+ *  drivers/acpi/processor_idle.c
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/cpuidle.h>
+#include <linux/cpu.h>
+
+#include <asm/paca.h>
+#include <asm/reg.h>
+#include <asm/system.h>
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+
+#include "plpar_wrappers.h"
+#include "pseries.h"
+
+struct cpuidle_driver pseries_idle_driver = {
+	.name =		"pseries_idle",
+	.owner =	THIS_MODULE,
+};
+
+#define MAX_IDLE_STATE_COUNT	2
+
+static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
+static struct cpuidle_device __percpu *pseries_cpuidle_devices;
+static struct cpuidle_state *cpuidle_state_table;
+
+void update_smt_snooze_delay(int snooze)
+{
+	struct cpuidle_driver *drv = cpuidle_get_driver();
+	if (drv)
+		drv->states[0].target_residency = snooze;
+}
+
+static inline void idle_loop_prolog(unsigned long *in_purr, ktime_t *kt_before)
+{
+
+	*kt_before = ktime_get_real();
+	*in_purr = mfspr(SPRN_PURR);
+	/*
+	 * Indicate to the HV that we are idle. Now would be
+	 * a good time to find other work to dispatch.
+	 */
+	get_lppaca()->idle = 1;
+}
+
+static inline  s64 idle_loop_epilog(unsigned long in_purr, ktime_t kt_before)
+{
+	get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr;
+	get_lppaca()->idle = 0;
+
+	return ktime_to_us(ktime_sub(ktime_get_real(), kt_before));
+}
+
+static int snooze_loop(struct cpuidle_device *dev,
+			struct cpuidle_driver *drv,
+			int index)
+{
+	unsigned long in_purr;
+	ktime_t kt_before;
+	unsigned long start_snooze;
+	long snooze = drv->states[0].target_residency;
+
+	idle_loop_prolog(&in_purr, &kt_before);
+
+	if (snooze) {
+		start_snooze = get_tb() + snooze * tb_ticks_per_usec;
+		local_irq_enable();
+		set_thread_flag(TIF_POLLING_NRFLAG);
+
+		while ((snooze < 0) || (get_tb() < start_snooze)) {
+			if (need_resched() || cpu_is_offline(dev->cpu))
+				goto out;
+			ppc64_runlatch_off();
+			HMT_low();
+			HMT_very_low();
+		}	
+
+		HMT_medium();
+		clear_thread_flag(TIF_POLLING_NRFLAG);
+		smp_mb();
+		local_irq_disable();
+	}
+
+out:
+	HMT_medium();
+	dev->last_residency =
+		(int)idle_loop_epilog(in_purr, kt_before);
+	return index;
+}
+
+static int dedicated_cede_loop(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv,
+				int index)
+{
+	unsigned long in_purr;
+	ktime_t kt_before;
+
+	idle_loop_prolog(&in_purr, &kt_before);
+	get_lppaca()->donate_dedicated_cpu = 1;
+
+	ppc64_runlatch_off();
+	HMT_medium();
+	cede_processor();
+
+	get_lppaca()->donate_dedicated_cpu = 0;
+	dev->last_residency =
+		(int)idle_loop_epilog(in_purr, kt_before);
+	return index;
+}
+
+static int shared_cede_loop(struct cpuidle_device *dev,
+			struct cpuidle_driver *drv,
+			int index)
+{
+	unsigned long in_purr;
+	ktime_t kt_before;
+
+	idle_loop_prolog(&in_purr, &kt_before);
+
+	/*
+	 * Yield the processor to the hypervisor.  We return if
+	 * an external interrupt occurs (which are driven prior
+	 * to returning here) or if a prod occurs from another
+	 * processor. When returning here, external interrupts
+	 * are enabled.
+	 */
+	cede_processor();
+
+	dev->last_residency =
+		(int)idle_loop_epilog(in_purr, kt_before);
+	return index;
+}
+
+/*
+ * States for dedicated partition case.
+ */
+static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = {
+	{ /* Snooze */
+		.name = "snooze",
+		.desc = "snooze",
+		.flags = CPUIDLE_FLAG_TIME_VALID,
+		.exit_latency = 0,
+		.target_residency = 0,
+		.enter = &snooze_loop },
+	{ /* CEDE */
+		.name = "CEDE",
+		.desc = "CEDE",
+		.flags = CPUIDLE_FLAG_TIME_VALID,
+		.exit_latency = 1,
+		.target_residency = 10,
+		.enter = &dedicated_cede_loop },
+};
+
+/*
+ * States for shared partition case.
+ */
+static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
+	{ /* Shared Cede */
+		.name = "Shared Cede",
+		.desc = "Shared Cede",
+		.flags = CPUIDLE_FLAG_TIME_VALID,
+		.exit_latency = 0,
+		.target_residency = 0,
+		.enter = &shared_cede_loop },
+};
+
+int pseries_notify_cpuidle_add_cpu(int cpu)
+{
+	struct cpuidle_device *dev =
+			per_cpu_ptr(pseries_cpuidle_devices, cpu);
+	if (dev && cpuidle_get_driver()) {
+		cpuidle_disable_device(dev);
+		cpuidle_enable_device(dev);
+	}
+	return 0;
+}
+
+/*
+ * pseries_cpuidle_driver_init()
+ */
+static int pseries_cpuidle_driver_init(void)
+{
+	int idle_state;
+	struct cpuidle_driver *drv = &pseries_idle_driver;
+
+	drv->state_count = 0;
+
+	for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) {
+
+		if (idle_state > max_idle_state)
+			break;
+
+		/* is the state not enabled? */
+		if (cpuidle_state_table[idle_state].enter == NULL)
+			continue;
+
+		drv->states[drv->state_count] =	/* structure copy */
+			cpuidle_state_table[idle_state];
+
+		if (cpuidle_state_table == dedicated_states)
+			drv->states[drv->state_count].target_residency =
+				__get_cpu_var(smt_snooze_delay);
+
+		drv->state_count += 1;
+	}
+
+	return 0;
+}
+
+/* pseries_idle_devices_uninit(void)
+ * unregister cpuidle devices and de-allocate memory
+ */
+static void pseries_idle_devices_uninit(void)
+{
+	int i;
+	struct cpuidle_device *dev;
+
+	for_each_possible_cpu(i) {
+		dev = per_cpu_ptr(pseries_cpuidle_devices, i);
+		cpuidle_unregister_device(dev);
+	}
+
+	free_percpu(pseries_cpuidle_devices);
+	return;
+}
+
+/* pseries_idle_devices_init()
+ * allocate, initialize and register cpuidle device
+ */
+static int pseries_idle_devices_init(void)
+{
+	int i;
+	struct cpuidle_driver *drv = &pseries_idle_driver;
+	struct cpuidle_device *dev;
+
+	pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device);
+	if (pseries_cpuidle_devices == NULL)
+		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		dev = per_cpu_ptr(pseries_cpuidle_devices, i);
+		dev->state_count = drv->state_count;
+		dev->cpu = i;
+		if (cpuidle_register_device(dev)) {
+			printk(KERN_DEBUG \
+				"cpuidle_register_device %d failed!\n", i);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * pseries_idle_probe()
+ * Choose state table for shared versus dedicated partition
+ */
+static int pseries_idle_probe(void)
+{
+
+	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
+		return -ENODEV;
+
+	if (max_idle_state == 0) {
+		printk(KERN_DEBUG "pseries processor idle disabled.\n");
+		return -EPERM;
+	}
+
+	if (get_lppaca()->shared_proc)
+		cpuidle_state_table = shared_states;
+	else
+		cpuidle_state_table = dedicated_states;
+
+	return 0;
+}
+
+static int __init pseries_processor_idle_init(void)
+{
+	int retval;
+
+	retval = pseries_idle_probe();
+	if (retval)
+		return retval;
+
+	pseries_cpuidle_driver_init();
+	retval = cpuidle_register_driver(&pseries_idle_driver);
+	if (retval) {
+		printk(KERN_DEBUG "Registration of pseries driver failed.\n");
+		return retval;
+	}
+
+	retval = pseries_idle_devices_init();
+	if (retval) {
+		pseries_idle_devices_uninit();
+		cpuidle_unregister_driver(&pseries_idle_driver);
+		return retval;
+	}
+
+	printk(KERN_DEBUG "pseries_idle_driver registered\n");
+
+	return 0;
+}
+
+static void __exit pseries_processor_idle_exit(void)
+{
+
+	pseries_idle_devices_uninit();
+	cpuidle_unregister_driver(&pseries_idle_driver);
+
+	return;
+}
+
+module_init(pseries_processor_idle_init);
+module_exit(pseries_processor_idle_exit);
+
+MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("Cpuidle driver for POWER");
+MODULE_LICENSE("GPL");
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 24c7162..9a3dda0 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -57,4 +57,7 @@ extern struct device_node *dlpar_configure_connector(u32);
 extern int dlpar_attach_node(struct device_node *);
 extern int dlpar_detach_node(struct device_node *);
 
+/* Snooze Delay, pseries_idle */
+DECLARE_PER_CPU(long, smt_snooze_delay);
+
 #endif /* _PSERIES_PSERIES_H */
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index c3408ca..9c6716a 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -586,9 +586,6 @@ static int __init pSeries_probe(void)
 	return 1;
 }
 
-
-DECLARE_PER_CPU(long, smt_snooze_delay);
-
 static void pseries_dedicated_idle_sleep(void)
 { 
 	unsigned int cpu = smp_processor_id();
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 26e93fd..bbc3c42 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -148,6 +148,7 @@ static void __devinit smp_xics_setup_cpu(int cpu)
 	set_cpu_current_state(cpu, CPU_STATE_ONLINE);
 	set_default_offline_state(cpu);
 #endif
+	pseries_notify_cpuidle_add_cpu(cpu);
 }
 
 static int __devinit smp_pSeries_kick_cpu(int nr)

[RFC PATCH v3 3/4] cpuidle: (POWER) Enable cpuidle and directly call cpuidle_idle_call() for pSeries

[Deepthi Dharwar]

This patch enables cpuidle for pSeries and pSeries_idle is
directly called from the idle loop. As a result of pSeries_idle, cpuidle
driver registered with cpuidle subsystem comes into action. On
failure of loading of the driver or cpuidle framework default idle
is executed as part of the function. This patch
also removes the routines pseries_shared_idle_sleep and
pseries_dedicated_idle_sleep as they are now implemented as part of
pseries_idle cpuidle driver.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: Arun R Bharadwaj <arun.r.bharadwaj@gmail.com>
---
 arch/powerpc/platforms/Kconfig         |    6 ++
 arch/powerpc/platforms/pseries/setup.c |  101 +++++---------------------------
 include/linux/cpuidle.h                |    2 -
 3 files changed, 23 insertions(+), 86 deletions(-)

diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 3fe6d92..31e1ade 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -211,6 +211,12 @@ config PPC_PASEMI_CPUFREQ
 
 endmenu
 
+menu "CPUIdle driver"
+
+source "drivers/cpuidle/Kconfig"
+
+endmenu
+
 config PPC601_SYNC_FIX
 	bool "Workarounds for PPC601 bugs"
 	depends on 6xx && (PPC_PREP || PPC_PMAC)
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 9c6716a..f19fc52 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -39,6 +39,7 @@
 #include <linux/irq.h>
 #include <linux/seq_file.h>
 #include <linux/root_dev.h>
+#include <linux/cpuidle.h>
 
 #include <asm/mmu.h>
 #include <asm/processor.h>
@@ -74,9 +75,6 @@ EXPORT_SYMBOL(CMO_PageSize);
 
 int fwnmi_active;  /* TRUE if an FWNMI handler is present */
 
-static void pseries_shared_idle_sleep(void);
-static void pseries_dedicated_idle_sleep(void);
-
 static struct device_node *pSeries_mpic_node;
 
 static void pSeries_show_cpuinfo(struct seq_file *m)
@@ -352,6 +350,21 @@ static int alloc_dispatch_log_kmem_cache(void)
 }
 early_initcall(alloc_dispatch_log_kmem_cache);
 
+static void pSeries_idle(void)
+{
+	/* This would call on the cpuidle framework, and the back-end pseries
+	 * driver to  go to idle states
+	 */
+	if (cpuidle_idle_call()) {
+		/* On error, execute default handler
+		 * to go into low thread priority and possibly
+		 * low power mode.
+		 */
+		HMT_low();
+		HMT_very_low();
+	}
+}
+
 static void __init pSeries_setup_arch(void)
 {
 	/* Discover PIC type and setup ppc_md accordingly */
@@ -374,18 +387,9 @@ static void __init pSeries_setup_arch(void)
 
 	pSeries_nvram_init();
 
-	/* Choose an idle loop */
 	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 		vpa_init(boot_cpuid);
-		if (get_lppaca()->shared_proc) {
-			printk(KERN_DEBUG "Using shared processor idle loop\n");
-			ppc_md.power_save = pseries_shared_idle_sleep;
-		} else {
-			printk(KERN_DEBUG "Using dedicated idle loop\n");
-			ppc_md.power_save = pseries_dedicated_idle_sleep;
-		}
-	} else {
-		printk(KERN_DEBUG "Using default idle loop\n");
+		ppc_md.power_save = pSeries_idle;
 	}
 
 	if (firmware_has_feature(FW_FEATURE_LPAR))
@@ -586,77 +590,6 @@ static int __init pSeries_probe(void)
 	return 1;
 }
 
-static void pseries_dedicated_idle_sleep(void)
-{ 
-	unsigned int cpu = smp_processor_id();
-	unsigned long start_snooze;
-	unsigned long in_purr, out_purr;
-	long snooze = __get_cpu_var(smt_snooze_delay);
-
-	/*
-	 * Indicate to the HV that we are idle. Now would be
-	 * a good time to find other work to dispatch.
-	 */
-	get_lppaca()->idle = 1;
-	get_lppaca()->donate_dedicated_cpu = 1;
-	in_purr = mfspr(SPRN_PURR);
-
-	/*
-	 * We come in with interrupts disabled, and need_resched()
-	 * has been checked recently.  If we should poll for a little
-	 * while, do so.
-	 */
-	if (snooze) {
-		start_snooze = get_tb() + snooze * tb_ticks_per_usec;
-		local_irq_enable();
-		set_thread_flag(TIF_POLLING_NRFLAG);
-
-		while ((snooze < 0) || (get_tb() < start_snooze)) {
-			if (need_resched() || cpu_is_offline(cpu))
-				goto out;
-			ppc64_runlatch_off();
-			HMT_low();
-			HMT_very_low();
-		}
-
-		HMT_medium();
-		clear_thread_flag(TIF_POLLING_NRFLAG);
-		smp_mb();
-		local_irq_disable();
-		if (need_resched() || cpu_is_offline(cpu))
-			goto out;
-	}
-
-	cede_processor();
-
-out:
-	HMT_medium();
-	out_purr = mfspr(SPRN_PURR);
-	get_lppaca()->wait_state_cycles += out_purr - in_purr;
-	get_lppaca()->donate_dedicated_cpu = 0;
-	get_lppaca()->idle = 0;
-}
-
-static void pseries_shared_idle_sleep(void)
-{
-	/*
-	 * Indicate to the HV that we are idle. Now would be
-	 * a good time to find other work to dispatch.
-	 */
-	get_lppaca()->idle = 1;
-
-	/*
-	 * Yield the processor to the hypervisor.  We return if
-	 * an external interrupt occurs (which are driven prior
-	 * to returning here) or if a prod occurs from another
-	 * processor. When returning here, external interrupts
-	 * are enabled.
-	 */
-	cede_processor();
-
-	get_lppaca()->idle = 0;
-}
-
 static int pSeries_pci_probe_mode(struct pci_bus *bus)
 {
 	if (firmware_has_feature(FW_FEATURE_LPAR))
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 7408af8..23f81de 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -130,7 +130,6 @@ struct cpuidle_driver {
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
 extern int cpuidle_idle_call(void);
-
 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 struct cpuidle_driver *cpuidle_get_driver(void);
 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
@@ -145,7 +144,6 @@ extern void cpuidle_disable_device(struct cpuidle_device *dev);
 #else
 static inline void disable_cpuidle(void) { }
 static inline int cpuidle_idle_call(void) { return -ENODEV; }
-
 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 {return -ENODEV; }
 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }

[RFC PATCH v3 4/4] cpuidle: (POWER) Handle power_save=off

[Deepthi Dharwar]

This patch makes pseries_idle_driver not to be registered when
power_save=off kernel boot option is specified. The
cpuidle_disable variable used here is similar to
its usage on x86. If cpuidle_disable is set then
sysfs entries for cpuidle framework are not created
and the required drivers are not loaded.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Signed-off-by: Arun R Bharadwaj <arun.r.bharadwaj@gmail.com>
---
 arch/powerpc/include/asm/processor.h            |    1 +
 arch/powerpc/platforms/pseries/processor_idle.c |    3 +++
 2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 811b7e7..b585bff 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -382,6 +382,7 @@ static inline unsigned long get_clean_sp(struct pt_regs *regs, int is_32)
 }
 #endif
 
+extern unsigned long cpuidle_disable;
 enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
index 352b78a..4f59af0 100644
--- a/arch/powerpc/platforms/pseries/processor_idle.c
+++ b/arch/powerpc/platforms/pseries/processor_idle.c
@@ -269,6 +269,9 @@ static int pseries_idle_probe(void)
 	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
 		return -ENODEV;
 
+	if (cpuidle_disable != IDLE_NO_OVERRIDE)
+		return -ENODEV;
+
 	if (max_idle_state == 0) {
 		printk(KERN_DEBUG "pseries processor idle disabled.\n");
 		return -EPERM;