Patchwork [V7,1/7] pseries/cpuidle: Move processor_idle.c to drivers/cpuidle.

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Submitter Deepthi Dharwar
Date Oct. 29, 2013, 11:01 a.m.
Message ID <20131029110120.31547.77532.stgit@deepthi.in.ibm.com>
Download mbox | patch
Permalink /patch/286785/
State Superseded
Headers show

Comments

Deepthi Dharwar - Oct. 29, 2013, 11:01 a.m.
Move the file from arch specific pseries/processor_idle.c
to drivers/cpuidle/cpuidle-ibm-power.c
Make the relevant Makefile and Kconfig changes.
This will enable having a common backend cpuidle driver
for POWER platform going forward.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/processor.h            |    2 
 arch/powerpc/platforms/pseries/Kconfig          |    9 -
 arch/powerpc/platforms/pseries/Makefile         |    1 
 arch/powerpc/platforms/pseries/processor_idle.c |  364 -----------------------
 drivers/cpuidle/Kconfig                         |    5 
 drivers/cpuidle/Kconfig.powerpc                 |   10 +
 drivers/cpuidle/Makefile                        |    4 
 drivers/cpuidle/cpuidle-ibm-power.c             |  364 +++++++++++++++++++++++
 8 files changed, 384 insertions(+), 375 deletions(-)
 delete mode 100644 arch/powerpc/platforms/pseries/processor_idle.c
 create mode 100644 drivers/cpuidle/Kconfig.powerpc
 create mode 100644 drivers/cpuidle/cpuidle-ibm-power.c
Daniel Lezcano - Nov. 6, 2013, 8:58 p.m.
On 10/29/2013 12:01 PM, Deepthi Dharwar wrote:
> Move the file from arch specific pseries/processor_idle.c
> to drivers/cpuidle/cpuidle-ibm-power.c
> Make the relevant Makefile and Kconfig changes.
> This will enable having a common backend cpuidle driver
> for POWER platform going forward.
>
> Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

> ---
>   arch/powerpc/include/asm/processor.h            |    2
>   arch/powerpc/platforms/pseries/Kconfig          |    9 -
>   arch/powerpc/platforms/pseries/Makefile         |    1
>   arch/powerpc/platforms/pseries/processor_idle.c |  364 -----------------------
>   drivers/cpuidle/Kconfig                         |    5
>   drivers/cpuidle/Kconfig.powerpc                 |   10 +
>   drivers/cpuidle/Makefile                        |    4
>   drivers/cpuidle/cpuidle-ibm-power.c             |  364 +++++++++++++++++++++++
>   8 files changed, 384 insertions(+), 375 deletions(-)
>   delete mode 100644 arch/powerpc/platforms/pseries/processor_idle.c
>   create mode 100644 drivers/cpuidle/Kconfig.powerpc
>   create mode 100644 drivers/cpuidle/cpuidle-ibm-power.c
>
> diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
> index ce4de5a..d53bb88 100644
> --- a/arch/powerpc/include/asm/processor.h
> +++ b/arch/powerpc/include/asm/processor.h
> @@ -428,7 +428,7 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
>   extern int powersave_nap;	/* set if nap mode can be used in idle loop */
>   extern void power7_nap(void);
>
> -#ifdef CONFIG_PSERIES_IDLE
> +#ifdef CONFIG_CPU_IDLE_IBM_POWER
>   extern void update_smt_snooze_delay(int cpu, int residency);
>   #else
>   static inline void update_smt_snooze_delay(int cpu, int residency) {}
> diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
> index 62b4f80..bb59bb0 100644
> --- a/arch/powerpc/platforms/pseries/Kconfig
> +++ b/arch/powerpc/platforms/pseries/Kconfig
> @@ -119,12 +119,3 @@ config DTL
>   	  which are accessible through a debugfs file.
>
>   	  Say N if you are unsure.
> -
> -config PSERIES_IDLE
> -	bool "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 6c61ec5..6f2500b 100644
> --- a/arch/powerpc/platforms/pseries/Makefile
> +++ b/arch/powerpc/platforms/pseries/Makefile
> @@ -21,7 +21,6 @@ obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
>   obj-$(CONFIG_CMM)		+= cmm.o
>   obj-$(CONFIG_DTL)		+= dtl.o
>   obj-$(CONFIG_IO_EVENT_IRQ)	+= io_event_irq.o
> -obj-$(CONFIG_PSERIES_IDLE)	+= processor_idle.o
>   obj-$(CONFIG_LPARCFG)		+= lparcfg.o
>
>   ifeq ($(CONFIG_PPC_PSERIES),y)
> diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
> deleted file mode 100644
> index a166e38..0000000
> --- a/arch/powerpc/platforms/pseries/processor_idle.c
> +++ /dev/null
> @@ -1,364 +0,0 @@
> -/*
> - *  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 <linux/notifier.h>
> -
> -#include <asm/paca.h>
> -#include <asm/reg.h>
> -#include <asm/machdep.h>
> -#include <asm/firmware.h>
> -#include <asm/runlatch.h>
> -#include <asm/plpar_wrappers.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;
> -
> -static inline void idle_loop_prolog(unsigned long *in_purr)
> -{
> -	*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 void idle_loop_epilog(unsigned long in_purr)
> -{
> -	u64 wait_cycles;
> -
> -	wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
> -	wait_cycles += mfspr(SPRN_PURR) - in_purr;
> -	get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
> -	get_lppaca()->idle = 0;
> -}
> -
> -static int snooze_loop(struct cpuidle_device *dev,
> -			struct cpuidle_driver *drv,
> -			int index)
> -{
> -	unsigned long in_purr;
> -	int cpu = dev->cpu;
> -
> -	idle_loop_prolog(&in_purr);
> -	local_irq_enable();
> -	set_thread_flag(TIF_POLLING_NRFLAG);
> -
> -	while ((!need_resched()) && cpu_online(cpu)) {
> -		ppc64_runlatch_off();
> -		HMT_low();
> -		HMT_very_low();
> -	}
> -
> -	HMT_medium();
> -	clear_thread_flag(TIF_POLLING_NRFLAG);
> -	smp_mb();
> -
> -	idle_loop_epilog(in_purr);
> -
> -	return index;
> -}
> -
> -static void check_and_cede_processor(void)
> -{
> -	/*
> -	 * Ensure our interrupt state is properly tracked,
> -	 * also checks if no interrupt has occurred while we
> -	 * were soft-disabled
> -	 */
> -	if (prep_irq_for_idle()) {
> -		cede_processor();
> -#ifdef CONFIG_TRACE_IRQFLAGS
> -		/* Ensure that H_CEDE returns with IRQs on */
> -		if (WARN_ON(!(mfmsr() & MSR_EE)))
> -			__hard_irq_enable();
> -#endif
> -	}
> -}
> -
> -static int dedicated_cede_loop(struct cpuidle_device *dev,
> -				struct cpuidle_driver *drv,
> -				int index)
> -{
> -	unsigned long in_purr;
> -
> -	idle_loop_prolog(&in_purr);
> -	get_lppaca()->donate_dedicated_cpu = 1;
> -
> -	ppc64_runlatch_off();
> -	HMT_medium();
> -	check_and_cede_processor();
> -
> -	get_lppaca()->donate_dedicated_cpu = 0;
> -
> -	idle_loop_epilog(in_purr);
> -
> -	return index;
> -}
> -
> -static int shared_cede_loop(struct cpuidle_device *dev,
> -			struct cpuidle_driver *drv,
> -			int index)
> -{
> -	unsigned long in_purr;
> -
> -	idle_loop_prolog(&in_purr);
> -
> -	/*
> -	 * 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.
> -	 */
> -	check_and_cede_processor();
> -
> -	idle_loop_epilog(in_purr);
> -
> -	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 = 10,
> -		.target_residency = 100,
> -		.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 },
> -};
> -
> -void update_smt_snooze_delay(int cpu, int residency)
> -{
> -	struct cpuidle_driver *drv = cpuidle_get_driver();
> -	struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
> -
> -	if (cpuidle_state_table != dedicated_states)
> -		return;
> -
> -	if (residency < 0) {
> -		/* Disable the Nap state on that cpu */
> -		if (dev)
> -			dev->states_usage[1].disable = 1;
> -	} else
> -		if (drv)
> -			drv->states[1].target_residency = residency;
> -}
> -
> -static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
> -			unsigned long action, void *hcpu)
> -{
> -	int hotcpu = (unsigned long)hcpu;
> -	struct cpuidle_device *dev =
> -			per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
> -
> -	if (dev && cpuidle_get_driver()) {
> -		switch (action) {
> -		case CPU_ONLINE:
> -		case CPU_ONLINE_FROZEN:
> -			cpuidle_pause_and_lock();
> -			cpuidle_enable_device(dev);
> -			cpuidle_resume_and_unlock();
> -			break;
> -
> -		case CPU_DEAD:
> -		case CPU_DEAD_FROZEN:
> -			cpuidle_pause_and_lock();
> -			cpuidle_disable_device(dev);
> -			cpuidle_resume_and_unlock();
> -			break;
> -
> -		default:
> -			return NOTIFY_DONE;
> -		}
> -	}
> -	return NOTIFY_OK;
> -}
> -
> -static struct notifier_block setup_hotplug_notifier = {
> -	.notifier_call = pseries_cpuidle_add_cpu_notifier,
> -};
> -
> -/*
> - * 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];
> -
> -		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 (cpuidle_disable != IDLE_NO_OVERRIDE)
> -		return -ENODEV;
> -
> -	if (max_idle_state == 0) {
> -		printk(KERN_DEBUG "pseries processor idle disabled.\n");
> -		return -EPERM;
> -	}
> -
> -	if (lppaca_shared_proc(get_lppaca()))
> -		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;
> -	}
> -
> -	register_cpu_notifier(&setup_hotplug_notifier);
> -	printk(KERN_DEBUG "pseries_idle_driver registered\n");
> -
> -	return 0;
> -}
> -
> -static void __exit pseries_processor_idle_exit(void)
> -{
> -
> -	unregister_cpu_notifier(&setup_hotplug_notifier);
> -	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/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
> index b3fb81d..f04e25f 100644
> --- a/drivers/cpuidle/Kconfig
> +++ b/drivers/cpuidle/Kconfig
> @@ -35,6 +35,11 @@ depends on ARM
>   source "drivers/cpuidle/Kconfig.arm"
>   endmenu
>
> +menu "POWERPC CPU Idle Drivers"
> +depends on PPC
> +source "drivers/cpuidle/Kconfig.powerpc"
> +endmenu
> +
>   endif
>
>   config ARCH_NEEDS_CPU_IDLE_COUPLED
> diff --git a/drivers/cpuidle/Kconfig.powerpc b/drivers/cpuidle/Kconfig.powerpc
> new file mode 100644
> index 0000000..8f43dc2
> --- /dev/null
> +++ b/drivers/cpuidle/Kconfig.powerpc
> @@ -0,0 +1,10 @@
> +#
> +# POWERPC CPU Idle Drivers
> +#
> +config CPU_IDLE_IBM_POWER
> +	bool "CPU Idle driver for IBM POWER platforms"
> +	depends on PPC_PSERIES
> +	default y
> +	help
> +	Select this option to enable processor idle state management
> +	on IBM POWER platform.
> diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
> index cea5ef5..60e7a6c 100644
> --- a/drivers/cpuidle/Makefile
> +++ b/drivers/cpuidle/Makefile
> @@ -12,3 +12,7 @@ obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE)	+= cpuidle-kirkwood.o
>   obj-$(CONFIG_ARM_ZYNQ_CPUIDLE)		+= cpuidle-zynq.o
>   obj-$(CONFIG_ARM_U8500_CPUIDLE)         += cpuidle-ux500.o
>   obj-$(CONFIG_CPU_IDLE_BIG_LITTLE)	+= cpuidle-big_little.o
> +
> +###############################################################################
> +# POWERPC drivers
> +obj-$(CONFIG_CPU_IDLE_IBM_POWER) += cpuidle-ibm-power.o
> diff --git a/drivers/cpuidle/cpuidle-ibm-power.c b/drivers/cpuidle/cpuidle-ibm-power.c
> new file mode 100644
> index 0000000..a166e38
> --- /dev/null
> +++ b/drivers/cpuidle/cpuidle-ibm-power.c
> @@ -0,0 +1,364 @@
> +/*
> + *  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 <linux/notifier.h>
> +
> +#include <asm/paca.h>
> +#include <asm/reg.h>
> +#include <asm/machdep.h>
> +#include <asm/firmware.h>
> +#include <asm/runlatch.h>
> +#include <asm/plpar_wrappers.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;
> +
> +static inline void idle_loop_prolog(unsigned long *in_purr)
> +{
> +	*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 void idle_loop_epilog(unsigned long in_purr)
> +{
> +	u64 wait_cycles;
> +
> +	wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
> +	wait_cycles += mfspr(SPRN_PURR) - in_purr;
> +	get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
> +	get_lppaca()->idle = 0;
> +}
> +
> +static int snooze_loop(struct cpuidle_device *dev,
> +			struct cpuidle_driver *drv,
> +			int index)
> +{
> +	unsigned long in_purr;
> +	int cpu = dev->cpu;
> +
> +	idle_loop_prolog(&in_purr);
> +	local_irq_enable();
> +	set_thread_flag(TIF_POLLING_NRFLAG);
> +
> +	while ((!need_resched()) && cpu_online(cpu)) {
> +		ppc64_runlatch_off();
> +		HMT_low();
> +		HMT_very_low();
> +	}
> +
> +	HMT_medium();
> +	clear_thread_flag(TIF_POLLING_NRFLAG);
> +	smp_mb();
> +
> +	idle_loop_epilog(in_purr);
> +
> +	return index;
> +}
> +
> +static void check_and_cede_processor(void)
> +{
> +	/*
> +	 * Ensure our interrupt state is properly tracked,
> +	 * also checks if no interrupt has occurred while we
> +	 * were soft-disabled
> +	 */
> +	if (prep_irq_for_idle()) {
> +		cede_processor();
> +#ifdef CONFIG_TRACE_IRQFLAGS
> +		/* Ensure that H_CEDE returns with IRQs on */
> +		if (WARN_ON(!(mfmsr() & MSR_EE)))
> +			__hard_irq_enable();
> +#endif
> +	}
> +}
> +
> +static int dedicated_cede_loop(struct cpuidle_device *dev,
> +				struct cpuidle_driver *drv,
> +				int index)
> +{
> +	unsigned long in_purr;
> +
> +	idle_loop_prolog(&in_purr);
> +	get_lppaca()->donate_dedicated_cpu = 1;
> +
> +	ppc64_runlatch_off();
> +	HMT_medium();
> +	check_and_cede_processor();
> +
> +	get_lppaca()->donate_dedicated_cpu = 0;
> +
> +	idle_loop_epilog(in_purr);
> +
> +	return index;
> +}
> +
> +static int shared_cede_loop(struct cpuidle_device *dev,
> +			struct cpuidle_driver *drv,
> +			int index)
> +{
> +	unsigned long in_purr;
> +
> +	idle_loop_prolog(&in_purr);
> +
> +	/*
> +	 * 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.
> +	 */
> +	check_and_cede_processor();
> +
> +	idle_loop_epilog(in_purr);
> +
> +	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 = 10,
> +		.target_residency = 100,
> +		.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 },
> +};
> +
> +void update_smt_snooze_delay(int cpu, int residency)
> +{
> +	struct cpuidle_driver *drv = cpuidle_get_driver();
> +	struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
> +
> +	if (cpuidle_state_table != dedicated_states)
> +		return;
> +
> +	if (residency < 0) {
> +		/* Disable the Nap state on that cpu */
> +		if (dev)
> +			dev->states_usage[1].disable = 1;
> +	} else
> +		if (drv)
> +			drv->states[1].target_residency = residency;
> +}
> +
> +static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
> +			unsigned long action, void *hcpu)
> +{
> +	int hotcpu = (unsigned long)hcpu;
> +	struct cpuidle_device *dev =
> +			per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
> +
> +	if (dev && cpuidle_get_driver()) {
> +		switch (action) {
> +		case CPU_ONLINE:
> +		case CPU_ONLINE_FROZEN:
> +			cpuidle_pause_and_lock();
> +			cpuidle_enable_device(dev);
> +			cpuidle_resume_and_unlock();
> +			break;
> +
> +		case CPU_DEAD:
> +		case CPU_DEAD_FROZEN:
> +			cpuidle_pause_and_lock();
> +			cpuidle_disable_device(dev);
> +			cpuidle_resume_and_unlock();
> +			break;
> +
> +		default:
> +			return NOTIFY_DONE;
> +		}
> +	}
> +	return NOTIFY_OK;
> +}
> +
> +static struct notifier_block setup_hotplug_notifier = {
> +	.notifier_call = pseries_cpuidle_add_cpu_notifier,
> +};
> +
> +/*
> + * 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];
> +
> +		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 (cpuidle_disable != IDLE_NO_OVERRIDE)
> +		return -ENODEV;
> +
> +	if (max_idle_state == 0) {
> +		printk(KERN_DEBUG "pseries processor idle disabled.\n");
> +		return -EPERM;
> +	}
> +
> +	if (lppaca_shared_proc(get_lppaca()))
> +		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;
> +	}
> +
> +	register_cpu_notifier(&setup_hotplug_notifier);
> +	printk(KERN_DEBUG "pseries_idle_driver registered\n");
> +
> +	return 0;
> +}
> +
> +static void __exit pseries_processor_idle_exit(void)
> +{
> +
> +	unregister_cpu_notifier(&setup_hotplug_notifier);
> +	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");
>

Patch

diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index ce4de5a..d53bb88 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -428,7 +428,7 @@  enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF};
 extern int powersave_nap;	/* set if nap mode can be used in idle loop */
 extern void power7_nap(void);
 
-#ifdef CONFIG_PSERIES_IDLE
+#ifdef CONFIG_CPU_IDLE_IBM_POWER
 extern void update_smt_snooze_delay(int cpu, int residency);
 #else
 static inline void update_smt_snooze_delay(int cpu, int residency) {}
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 62b4f80..bb59bb0 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -119,12 +119,3 @@  config DTL
 	  which are accessible through a debugfs file.
 
 	  Say N if you are unsure.
-
-config PSERIES_IDLE
-	bool "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 6c61ec5..6f2500b 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -21,7 +21,6 @@  obj-$(CONFIG_HCALL_STATS)	+= hvCall_inst.o
 obj-$(CONFIG_CMM)		+= cmm.o
 obj-$(CONFIG_DTL)		+= dtl.o
 obj-$(CONFIG_IO_EVENT_IRQ)	+= io_event_irq.o
-obj-$(CONFIG_PSERIES_IDLE)	+= processor_idle.o
 obj-$(CONFIG_LPARCFG)		+= lparcfg.o
 
 ifeq ($(CONFIG_PPC_PSERIES),y)
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
deleted file mode 100644
index a166e38..0000000
--- a/arch/powerpc/platforms/pseries/processor_idle.c
+++ /dev/null
@@ -1,364 +0,0 @@ 
-/*
- *  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 <linux/notifier.h>
-
-#include <asm/paca.h>
-#include <asm/reg.h>
-#include <asm/machdep.h>
-#include <asm/firmware.h>
-#include <asm/runlatch.h>
-#include <asm/plpar_wrappers.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;
-
-static inline void idle_loop_prolog(unsigned long *in_purr)
-{
-	*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 void idle_loop_epilog(unsigned long in_purr)
-{
-	u64 wait_cycles;
-
-	wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
-	wait_cycles += mfspr(SPRN_PURR) - in_purr;
-	get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
-	get_lppaca()->idle = 0;
-}
-
-static int snooze_loop(struct cpuidle_device *dev,
-			struct cpuidle_driver *drv,
-			int index)
-{
-	unsigned long in_purr;
-	int cpu = dev->cpu;
-
-	idle_loop_prolog(&in_purr);
-	local_irq_enable();
-	set_thread_flag(TIF_POLLING_NRFLAG);
-
-	while ((!need_resched()) && cpu_online(cpu)) {
-		ppc64_runlatch_off();
-		HMT_low();
-		HMT_very_low();
-	}
-
-	HMT_medium();
-	clear_thread_flag(TIF_POLLING_NRFLAG);
-	smp_mb();
-
-	idle_loop_epilog(in_purr);
-
-	return index;
-}
-
-static void check_and_cede_processor(void)
-{
-	/*
-	 * Ensure our interrupt state is properly tracked,
-	 * also checks if no interrupt has occurred while we
-	 * were soft-disabled
-	 */
-	if (prep_irq_for_idle()) {
-		cede_processor();
-#ifdef CONFIG_TRACE_IRQFLAGS
-		/* Ensure that H_CEDE returns with IRQs on */
-		if (WARN_ON(!(mfmsr() & MSR_EE)))
-			__hard_irq_enable();
-#endif
-	}
-}
-
-static int dedicated_cede_loop(struct cpuidle_device *dev,
-				struct cpuidle_driver *drv,
-				int index)
-{
-	unsigned long in_purr;
-
-	idle_loop_prolog(&in_purr);
-	get_lppaca()->donate_dedicated_cpu = 1;
-
-	ppc64_runlatch_off();
-	HMT_medium();
-	check_and_cede_processor();
-
-	get_lppaca()->donate_dedicated_cpu = 0;
-
-	idle_loop_epilog(in_purr);
-
-	return index;
-}
-
-static int shared_cede_loop(struct cpuidle_device *dev,
-			struct cpuidle_driver *drv,
-			int index)
-{
-	unsigned long in_purr;
-
-	idle_loop_prolog(&in_purr);
-
-	/*
-	 * 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.
-	 */
-	check_and_cede_processor();
-
-	idle_loop_epilog(in_purr);
-
-	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 = 10,
-		.target_residency = 100,
-		.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 },
-};
-
-void update_smt_snooze_delay(int cpu, int residency)
-{
-	struct cpuidle_driver *drv = cpuidle_get_driver();
-	struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
-
-	if (cpuidle_state_table != dedicated_states)
-		return;
-
-	if (residency < 0) {
-		/* Disable the Nap state on that cpu */
-		if (dev)
-			dev->states_usage[1].disable = 1;
-	} else
-		if (drv)
-			drv->states[1].target_residency = residency;
-}
-
-static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
-			unsigned long action, void *hcpu)
-{
-	int hotcpu = (unsigned long)hcpu;
-	struct cpuidle_device *dev =
-			per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
-
-	if (dev && cpuidle_get_driver()) {
-		switch (action) {
-		case CPU_ONLINE:
-		case CPU_ONLINE_FROZEN:
-			cpuidle_pause_and_lock();
-			cpuidle_enable_device(dev);
-			cpuidle_resume_and_unlock();
-			break;
-
-		case CPU_DEAD:
-		case CPU_DEAD_FROZEN:
-			cpuidle_pause_and_lock();
-			cpuidle_disable_device(dev);
-			cpuidle_resume_and_unlock();
-			break;
-
-		default:
-			return NOTIFY_DONE;
-		}
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block setup_hotplug_notifier = {
-	.notifier_call = pseries_cpuidle_add_cpu_notifier,
-};
-
-/*
- * 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];
-
-		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 (cpuidle_disable != IDLE_NO_OVERRIDE)
-		return -ENODEV;
-
-	if (max_idle_state == 0) {
-		printk(KERN_DEBUG "pseries processor idle disabled.\n");
-		return -EPERM;
-	}
-
-	if (lppaca_shared_proc(get_lppaca()))
-		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;
-	}
-
-	register_cpu_notifier(&setup_hotplug_notifier);
-	printk(KERN_DEBUG "pseries_idle_driver registered\n");
-
-	return 0;
-}
-
-static void __exit pseries_processor_idle_exit(void)
-{
-
-	unregister_cpu_notifier(&setup_hotplug_notifier);
-	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/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index b3fb81d..f04e25f 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -35,6 +35,11 @@  depends on ARM
 source "drivers/cpuidle/Kconfig.arm"
 endmenu
 
+menu "POWERPC CPU Idle Drivers"
+depends on PPC
+source "drivers/cpuidle/Kconfig.powerpc"
+endmenu
+
 endif
 
 config ARCH_NEEDS_CPU_IDLE_COUPLED
diff --git a/drivers/cpuidle/Kconfig.powerpc b/drivers/cpuidle/Kconfig.powerpc
new file mode 100644
index 0000000..8f43dc2
--- /dev/null
+++ b/drivers/cpuidle/Kconfig.powerpc
@@ -0,0 +1,10 @@ 
+#
+# POWERPC CPU Idle Drivers
+#
+config CPU_IDLE_IBM_POWER
+	bool "CPU Idle driver for IBM POWER platforms"
+	depends on PPC_PSERIES
+	default y
+	help
+	Select this option to enable processor idle state management
+	on IBM POWER platform.
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index cea5ef5..60e7a6c 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -12,3 +12,7 @@  obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE)	+= cpuidle-kirkwood.o
 obj-$(CONFIG_ARM_ZYNQ_CPUIDLE)		+= cpuidle-zynq.o
 obj-$(CONFIG_ARM_U8500_CPUIDLE)         += cpuidle-ux500.o
 obj-$(CONFIG_CPU_IDLE_BIG_LITTLE)	+= cpuidle-big_little.o
+
+###############################################################################
+# POWERPC drivers
+obj-$(CONFIG_CPU_IDLE_IBM_POWER) += cpuidle-ibm-power.o
diff --git a/drivers/cpuidle/cpuidle-ibm-power.c b/drivers/cpuidle/cpuidle-ibm-power.c
new file mode 100644
index 0000000..a166e38
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-ibm-power.c
@@ -0,0 +1,364 @@ 
+/*
+ *  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 <linux/notifier.h>
+
+#include <asm/paca.h>
+#include <asm/reg.h>
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+#include <asm/runlatch.h>
+#include <asm/plpar_wrappers.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;
+
+static inline void idle_loop_prolog(unsigned long *in_purr)
+{
+	*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 void idle_loop_epilog(unsigned long in_purr)
+{
+	u64 wait_cycles;
+
+	wait_cycles = be64_to_cpu(get_lppaca()->wait_state_cycles);
+	wait_cycles += mfspr(SPRN_PURR) - in_purr;
+	get_lppaca()->wait_state_cycles = cpu_to_be64(wait_cycles);
+	get_lppaca()->idle = 0;
+}
+
+static int snooze_loop(struct cpuidle_device *dev,
+			struct cpuidle_driver *drv,
+			int index)
+{
+	unsigned long in_purr;
+	int cpu = dev->cpu;
+
+	idle_loop_prolog(&in_purr);
+	local_irq_enable();
+	set_thread_flag(TIF_POLLING_NRFLAG);
+
+	while ((!need_resched()) && cpu_online(cpu)) {
+		ppc64_runlatch_off();
+		HMT_low();
+		HMT_very_low();
+	}
+
+	HMT_medium();
+	clear_thread_flag(TIF_POLLING_NRFLAG);
+	smp_mb();
+
+	idle_loop_epilog(in_purr);
+
+	return index;
+}
+
+static void check_and_cede_processor(void)
+{
+	/*
+	 * Ensure our interrupt state is properly tracked,
+	 * also checks if no interrupt has occurred while we
+	 * were soft-disabled
+	 */
+	if (prep_irq_for_idle()) {
+		cede_processor();
+#ifdef CONFIG_TRACE_IRQFLAGS
+		/* Ensure that H_CEDE returns with IRQs on */
+		if (WARN_ON(!(mfmsr() & MSR_EE)))
+			__hard_irq_enable();
+#endif
+	}
+}
+
+static int dedicated_cede_loop(struct cpuidle_device *dev,
+				struct cpuidle_driver *drv,
+				int index)
+{
+	unsigned long in_purr;
+
+	idle_loop_prolog(&in_purr);
+	get_lppaca()->donate_dedicated_cpu = 1;
+
+	ppc64_runlatch_off();
+	HMT_medium();
+	check_and_cede_processor();
+
+	get_lppaca()->donate_dedicated_cpu = 0;
+
+	idle_loop_epilog(in_purr);
+
+	return index;
+}
+
+static int shared_cede_loop(struct cpuidle_device *dev,
+			struct cpuidle_driver *drv,
+			int index)
+{
+	unsigned long in_purr;
+
+	idle_loop_prolog(&in_purr);
+
+	/*
+	 * 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.
+	 */
+	check_and_cede_processor();
+
+	idle_loop_epilog(in_purr);
+
+	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 = 10,
+		.target_residency = 100,
+		.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 },
+};
+
+void update_smt_snooze_delay(int cpu, int residency)
+{
+	struct cpuidle_driver *drv = cpuidle_get_driver();
+	struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
+
+	if (cpuidle_state_table != dedicated_states)
+		return;
+
+	if (residency < 0) {
+		/* Disable the Nap state on that cpu */
+		if (dev)
+			dev->states_usage[1].disable = 1;
+	} else
+		if (drv)
+			drv->states[1].target_residency = residency;
+}
+
+static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
+			unsigned long action, void *hcpu)
+{
+	int hotcpu = (unsigned long)hcpu;
+	struct cpuidle_device *dev =
+			per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
+
+	if (dev && cpuidle_get_driver()) {
+		switch (action) {
+		case CPU_ONLINE:
+		case CPU_ONLINE_FROZEN:
+			cpuidle_pause_and_lock();
+			cpuidle_enable_device(dev);
+			cpuidle_resume_and_unlock();
+			break;
+
+		case CPU_DEAD:
+		case CPU_DEAD_FROZEN:
+			cpuidle_pause_and_lock();
+			cpuidle_disable_device(dev);
+			cpuidle_resume_and_unlock();
+			break;
+
+		default:
+			return NOTIFY_DONE;
+		}
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block setup_hotplug_notifier = {
+	.notifier_call = pseries_cpuidle_add_cpu_notifier,
+};
+
+/*
+ * 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];
+
+		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 (cpuidle_disable != IDLE_NO_OVERRIDE)
+		return -ENODEV;
+
+	if (max_idle_state == 0) {
+		printk(KERN_DEBUG "pseries processor idle disabled.\n");
+		return -EPERM;
+	}
+
+	if (lppaca_shared_proc(get_lppaca()))
+		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;
+	}
+
+	register_cpu_notifier(&setup_hotplug_notifier);
+	printk(KERN_DEBUG "pseries_idle_driver registered\n");
+
+	return 0;
+}
+
+static void __exit pseries_processor_idle_exit(void)
+{
+
+	unregister_cpu_notifier(&setup_hotplug_notifier);
+	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");