Patchwork [RFC,V3,3/5] powerpc/cpuidle: Generic powerpc backend cpuidle driver.

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Submitter Deepthi Dharwar
Date Aug. 19, 2013, 4:28 a.m.
Message ID <20130819042818.8609.77060.stgit@deepthi.in.ibm.com>
Download mbox | patch
Permalink /patch/268083/
State Superseded
Headers show

Comments

Deepthi Dharwar - Aug. 19, 2013, 4:28 a.m.
This patch involves moving the current pseries_idle backend driver code
from pseries/processor_idle.c to drivers/cpuidle/cpuidle-powerpc.c,
and making the backend code generic enough to be able to  extend this
driver code for complete powerpc platform to exploit the cpuidle framework.

It enables the support for pseries platform, such that going forward the same code
with minimal efforts can be re-used for a common driver on powernv
and can be further extended to support cpuidle idle state mgmt for the rest
of the powerpc platforms. This removes a lot of code duplicacy, making
the code elegant.

Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/paca.h                 |   23 +
 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 |  360 -----------------------
 drivers/cpuidle/Kconfig                         |    7 
 drivers/cpuidle/Makefile                        |    2 
 drivers/cpuidle/cpuidle-powerpc.c               |  361 +++++++++++++++++++++++
 8 files changed, 394 insertions(+), 371 deletions(-)
 delete mode 100644 arch/powerpc/platforms/pseries/processor_idle.c
 create mode 100644 drivers/cpuidle/cpuidle-powerpc.c
Wang Dongsheng-B40534 - Aug. 19, 2013, 5:52 a.m.
I think we should move the states and handle function to arch/power/platform*
The states and handle function is belong to backend driver, not for this, different platform have different state.
Different platforms to make their own deal with these states.

I think we cannot put all the status of different platforms and handler in this driver.

> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
> index 0e2cd5c..99ee5d4 100644
> --- a/drivers/cpuidle/Kconfig
> +++ b/drivers/cpuidle/Kconfig
> @@ -42,6 +42,13 @@ config CPU_IDLE_ZYNQ
>  	help
>  	  Select this to enable cpuidle on Xilinx Zynq processors.
> 
> +config CPU_IDLE_POWERPC
> +	bool "CPU Idle driver for POWERPC platforms"
> +	depends on PPC64

Why not PPC?


> +	default y
> +        help
> +          Select this option to enable processor idle state management
> +	  for POWERPC platform.
>  endif
> 
>  config ARCH_NEEDS_CPU_IDLE_COUPLED
> diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
> index 8767a7b..d12e205 100644
> --- a/drivers/cpuidle/Makefile
> +++ b/drivers/cpuidle/Makefile
> @@ -8,3 +8,5 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
>  obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o
>  obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o
>  obj-$(CONFIG_CPU_IDLE_ZYNQ) += cpuidle-zynq.o
> +
> +obj-$(CONFIG_CPU_IDLE_POWERPC) += cpuidle-powerpc.o
> diff --git a/drivers/cpuidle/cpuidle-powerpc.c b/drivers/cpuidle/cpuidle-
> powerpc.c
> new file mode 100644
> index 0000000..5756085
> --- /dev/null
> +++ b/drivers/cpuidle/cpuidle-powerpc.c
> @@ -0,0 +1,361 @@
> +/*
> + *  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 powerpc_idle_driver = {
> +	.name             = "powerpc_idle",
> +	.owner            = THIS_MODULE,
> +};
> +
> +#define MAX_IDLE_STATE_COUNT	2
> +
> +static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
If this is a generic driver, do not define MAX_IDLE_STATE_COUNT, because we don't know how many state on other platforms.

How about using ARRAY_SIZE to get the max idle state?

> +static struct cpuidle_device __percpu *powerpc_cpuidle_devices;
> +static struct cpuidle_state *cpuidle_state_table;
> +
Should be remove all about *device*.
If the notifier handle using device, you can use "cpuidle_devices"(include/linux/cpuidle.h).

> +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.
> +	 */
> +	set_lppaca_idle(1);
> +}
> +
> +static inline void idle_loop_epilog(unsigned long in_purr)
> +{
> +	add_lppaca_wait_state(mfspr(SPRN_PURR) - in_purr);
> +	set_lppaca_idle(0);
> +}
> +
> +static int snooze_loop(struct cpuidle_device *dev,
> +			struct cpuidle_driver *drv,
> +			int index)
> +{
> +	unsigned long in_purr;
> +
> +	idle_loop_prolog(&in_purr);
> +	local_irq_enable();
> +	set_thread_flag(TIF_POLLING_NRFLAG);
> +
> +	while (!need_resched()) {
> +		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);
> +	set_lppaca_donate_dedicated_cpu(1);
> +
> +	ppc64_runlatch_off();
> +	HMT_medium();
> +	check_and_cede_processor();
> +
> +	set_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 powerpc_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(powerpc_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 = powerpc_cpuidle_add_cpu_notifier,
> +};
> +
We should discuss this with Daniel.

> +/*
> + * powerpc_cpuidle_driver_init()
> + */
> +static int powerpc_cpuidle_driver_init(void)
> +{
> +	int idle_state;
> +	struct cpuidle_driver *drv = &powerpc_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;
> +
Did the state have dependent?
If yes, may be should break out the loop, not continue.

> +		drv->states[drv->state_count] =	/* structure copy */
> +			cpuidle_state_table[idle_state];
> +
> +		drv->state_count += 1;
> +	}
> +
> +	return 0;
> +}
> +
> +/* powerpc_idle_devices_uninit(void)
> + * unregister cpuidle devices and de-allocate memory
> + */
> +static void powerpc_idle_devices_uninit(void)
> +{
> +	int i;
> +	struct cpuidle_device *dev;
> +
> +	for_each_possible_cpu(i) {
> +		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
> +		cpuidle_unregister_device(dev);
> +	}
> +
> +	free_percpu(powerpc_cpuidle_devices);
> +	return;
> +}
> +
> +/* powerpc_idle_devices_init()
> + * allocate, initialize and register cpuidle device
> + */
> +static int powerpc_idle_devices_init(void)
> +{
> +	int i;
> +	struct cpuidle_driver *drv = &powerpc_idle_driver;
> +	struct cpuidle_device *dev;
> +
> +	powerpc_cpuidle_devices = alloc_percpu(struct cpuidle_device);
> +	if (powerpc_cpuidle_devices == NULL)
> +		return -ENOMEM;
> +
> +	for_each_possible_cpu(i) {
> +		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
> +		dev->state_count = drv->state_count;
> +		dev->cpu = i;
> +		if (cpuidle_register_device(dev)) {

Please use cpuidle_register().

> +			printk(KERN_DEBUG \
> +				"cpuidle_register_device %d failed!\n", i);
> +			return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * powerpc_idle_probe()
> + * Choose state table for shared versus dedicated partition
> + */
> +static int powerpc_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 "powerpc processor idle disabled.\n");
> +		return -EPERM;
> +	}
> +
> +	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
> +		if (get_lppaca_is_shared_proc() == 1)
> +			cpuidle_state_table = shared_states;
> +		else if (get_lppaca_is_shared_proc() == 0)
> +			cpuidle_state_table = dedicated_states;
> +	} else
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +
> +static int __init powerpc_processor_idle_init(void)
> +{
> +	int retval;
> +
> +	retval = powerpc_idle_probe();
> +	if (retval)
> +		return retval;
> +
> +	powerpc_cpuidle_driver_init();
> +	retval = cpuidle_register_driver(&powerpc_idle_driver);
> +	if (retval) {
> +		printk(KERN_DEBUG "Registration of powerpc driver failed.\n");
> +		return retval;
> +	}
> +
> +	retval = powerpc_idle_devices_init();
> +	if (retval) {
> +		powerpc_idle_devices_uninit();
> +		cpuidle_unregister_driver(&powerpc_idle_driver);
> +		return retval;
> +	}
> +
> +	register_cpu_notifier(&setup_hotplug_notifier);
> +	printk(KERN_DEBUG "powerpc_idle_driver registered\n");
> +
> +	return 0;
> +}
> +
> +static void __exit powerpc_processor_idle_exit(void)
> +{
> +
> +	unregister_cpu_notifier(&setup_hotplug_notifier);
> +	powerpc_idle_devices_uninit();
> +	cpuidle_unregister_driver(&powerpc_idle_driver);
> +
> +	return;
> +}
> +
Did you test module mode? *Remove* the module cannot work.
>
Deepthi Dharwar - Aug. 19, 2013, 10:18 a.m.
Hi Dongsheng,

On 08/19/2013 11:22 AM, Wang Dongsheng-B40534 wrote:
> I think we should move the states and handle function to arch/power/platform*
> The states and handle function is belong to backend driver, not for this, different platform have different state.
> Different platforms to make their own deal with these states.
> 
> I think we cannot put all the status of different platforms and handler in this driver.

The idea here is a single powerpc back-end driver, which does a runtime
detection of the platform it is running and choose the right
idle states table. This was one of outcome of V2 discussion.

I feel there is no harm in keeping the state information in the same
file. We do have x86, which has all its variants information in one
file. One place will have all the idle consolidated information of
all the platform variants. If community does feel, we need to
have just the states information in arch specific file, we can do so.


>> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
>> index 0e2cd5c..99ee5d4 100644
>> --- a/drivers/cpuidle/Kconfig
>> +++ b/drivers/cpuidle/Kconfig
>> @@ -42,6 +42,13 @@ config CPU_IDLE_ZYNQ
>>  	help
>>  	  Select this to enable cpuidle on Xilinx Zynq processors.
>>
>> +config CPU_IDLE_POWERPC
>> +	bool "CPU Idle driver for POWERPC platforms"
>> +	depends on PPC64
> 
> Why not PPC?

PPC64 seems to a good place to began the consolidation work. This
patch-set has not been tested for PPC32 currently.

> 
>> +	default y
>> +        help
>> +          Select this option to enable processor idle state management
>> +	  for POWERPC platform.
>>  endif
>>
>>  config ARCH_NEEDS_CPU_IDLE_COUPLED
>> diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
>> index 8767a7b..d12e205 100644
>> --- a/drivers/cpuidle/Makefile
>> +++ b/drivers/cpuidle/Makefile
>> @@ -8,3 +8,5 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
>>  obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o
>>  obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o
>>  obj-$(CONFIG_CPU_IDLE_ZYNQ) += cpuidle-zynq.o
>> +
>> +obj-$(CONFIG_CPU_IDLE_POWERPC) += cpuidle-powerpc.o
>> diff --git a/drivers/cpuidle/cpuidle-powerpc.c b/drivers/cpuidle/cpuidle-
>> powerpc.c
>> new file mode 100644
>> index 0000000..5756085
>> --- /dev/null
>> +++ b/drivers/cpuidle/cpuidle-powerpc.c
>> @@ -0,0 +1,361 @@
>> +/*
>> + *  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 powerpc_idle_driver = {
>> +	.name             = "powerpc_idle",
>> +	.owner            = THIS_MODULE,
>> +};
>> +
>> +#define MAX_IDLE_STATE_COUNT	2
>> +
>> +static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
> If this is a generic driver, do not define MAX_IDLE_STATE_COUNT, because we don't know how many state on other platforms.
> 
> How about using ARRAY_SIZE to get the max idle state?
> 
Yes, I do agree. We need a generic way to return the no of idle states.

>> +static struct cpuidle_device __percpu *powerpc_cpuidle_devices;
>> +static struct cpuidle_state *cpuidle_state_table;
>> +
> Should be remove all about *device*.
> If the notifier handle using device, you can use "cpuidle_devices"(include/linux/cpuidle.h).

The hotplug notifier has a dependency to the cpu device struct.
Yes, I agree using this is way to go forward. As outlined in the cover
cpuidle cleanups will be taken in subsequent versions.

>> +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.
>> +	 */
>> +	set_lppaca_idle(1);
>> +}
>> +
>> +static inline void idle_loop_epilog(unsigned long in_purr)
>> +{
>> +	add_lppaca_wait_state(mfspr(SPRN_PURR) - in_purr);
>> +	set_lppaca_idle(0);
>> +}
>> +
>> +static int snooze_loop(struct cpuidle_device *dev,
>> +			struct cpuidle_driver *drv,
>> +			int index)
>> +{
>> +	unsigned long in_purr;
>> +
>> +	idle_loop_prolog(&in_purr);
>> +	local_irq_enable();
>> +	set_thread_flag(TIF_POLLING_NRFLAG);
>> +
>> +	while (!need_resched()) {
>> +		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);
>> +	set_lppaca_donate_dedicated_cpu(1);
>> +
>> +	ppc64_runlatch_off();
>> +	HMT_medium();
>> +	check_and_cede_processor();
>> +
>> +	set_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 powerpc_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(powerpc_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 = powerpc_cpuidle_add_cpu_notifier,
>> +};
>> +
> We should discuss this with Daniel.

Yes, having a single cpuidle hotplug notifier across
all archs removes a lot of code duplication. But this would involve
changes across archs that is a huge feature by itself and extensive
testing. This is not in the per-view of current patch series but will be
taken up separately.

>> +/*
>> + * powerpc_cpuidle_driver_init()
>> + */
>> +static int powerpc_cpuidle_driver_init(void)
>> +{
>> +	int idle_state;
>> +	struct cpuidle_driver *drv = &powerpc_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;
>> +
> Did the state have dependent?
> If yes, may be should break out the loop, not continue.

Dependent in what way ?

>> +		drv->states[drv->state_count] =	/* structure copy */
>> +			cpuidle_state_table[idle_state];
>> +
>> +		drv->state_count += 1;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/* powerpc_idle_devices_uninit(void)
>> + * unregister cpuidle devices and de-allocate memory
>> + */
>> +static void powerpc_idle_devices_uninit(void)
>> +{
>> +	int i;
>> +	struct cpuidle_device *dev;
>> +
>> +	for_each_possible_cpu(i) {
>> +		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
>> +		cpuidle_unregister_device(dev);
>> +	}
>> +
>> +	free_percpu(powerpc_cpuidle_devices);
>> +	return;
>> +}
>> +
>> +/* powerpc_idle_devices_init()
>> + * allocate, initialize and register cpuidle device
>> + */
>> +static int powerpc_idle_devices_init(void)
>> +{
>> +	int i;
>> +	struct cpuidle_driver *drv = &powerpc_idle_driver;
>> +	struct cpuidle_device *dev;
>> +
>> +	powerpc_cpuidle_devices = alloc_percpu(struct cpuidle_device);
>> +	if (powerpc_cpuidle_devices == NULL)
>> +		return -ENOMEM;
>> +
>> +	for_each_possible_cpu(i) {
>> +		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
>> +		dev->state_count = drv->state_count;
>> +		dev->cpu = i;
>> +		if (cpuidle_register_device(dev)) {
> 
> Please use cpuidle_register().
> 
>> +			printk(KERN_DEBUG \
>> +				"cpuidle_register_device %d failed!\n", i);
>> +			return -EIO;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * powerpc_idle_probe()
>> + * Choose state table for shared versus dedicated partition
>> + */
>> +static int powerpc_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 "powerpc processor idle disabled.\n");
>> +		return -EPERM;
>> +	}
>> +
>> +	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
>> +		if (get_lppaca_is_shared_proc() == 1)
>> +			cpuidle_state_table = shared_states;
>> +		else if (get_lppaca_is_shared_proc() == 0)
>> +			cpuidle_state_table = dedicated_states;
>> +	} else
>> +		return -ENODEV;
>> +
>> +	return 0;
>> +}
>> +
>> +static int __init powerpc_processor_idle_init(void)
>> +{
>> +	int retval;
>> +
>> +	retval = powerpc_idle_probe();
>> +	if (retval)
>> +		return retval;
>> +
>> +	powerpc_cpuidle_driver_init();
>> +	retval = cpuidle_register_driver(&powerpc_idle_driver);
>> +	if (retval) {
>> +		printk(KERN_DEBUG "Registration of powerpc driver failed.\n");
>> +		return retval;
>> +	}
>> +
>> +	retval = powerpc_idle_devices_init();
>> +	if (retval) {
>> +		powerpc_idle_devices_uninit();
>> +		cpuidle_unregister_driver(&powerpc_idle_driver);
>> +		return retval;
>> +	}
>> +
>> +	register_cpu_notifier(&setup_hotplug_notifier);
>> +	printk(KERN_DEBUG "powerpc_idle_driver registered\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static void __exit powerpc_processor_idle_exit(void)
>> +{
>> +
>> +	unregister_cpu_notifier(&setup_hotplug_notifier);
>> +	powerpc_idle_devices_uninit();
>> +	cpuidle_unregister_driver(&powerpc_idle_driver);
>> +
>> +	return;
>> +}
>> +
> Did you test module mode? *Remove* the module cannot work.
>>

This is currently in-built module as there is a dependency in
kernel/sysfs.c currently. Going forward we will look to have this as a
module.

This is just an RFC patch to see if we can go forward this line. Thanks
so much for the review. I have duly noted down the issues
that will be addressed in the coming versions.

Regards,
Deepthi


> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
> 
>
Scott Wood - Aug. 19, 2013, 6:17 p.m.
On Mon, 2013-08-19 at 15:48 +0530, Deepthi Dharwar wrote:
> Hi Dongsheng,
> 
> On 08/19/2013 11:22 AM, Wang Dongsheng-B40534 wrote:
> > I think we should move the states and handle function to arch/power/platform*
> > The states and handle function is belong to backend driver, not for this, different platform have different state.
> > Different platforms to make their own deal with these states.
> > 
> > I think we cannot put all the status of different platforms and handler in this driver.
> 
> The idea here is a single powerpc back-end driver, which does a runtime
> detection of the platform it is running and choose the right
> idle states table. This was one of outcome of V2 discussion.

I see a lot more in there than just detecting a platform and choosing a
driver.

> I feel there is no harm in keeping the state information in the same
> file. We do have x86, which has all its variants information in one
> file. One place will have all the idle consolidated information of
> all the platform variants. If community does feel, we need to
> have just the states information in arch specific file, we can do so.

What actual functionality is common to all powerpc but not common to
other arches?

> >> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
> >> index 0e2cd5c..99ee5d4 100644
> >> --- a/drivers/cpuidle/Kconfig
> >> +++ b/drivers/cpuidle/Kconfig
> >> @@ -42,6 +42,13 @@ config CPU_IDLE_ZYNQ
> >>  	help
> >>  	  Select this to enable cpuidle on Xilinx Zynq processors.
> >>
> >> +config CPU_IDLE_POWERPC
> >> +	bool "CPU Idle driver for POWERPC platforms"
> >> +	depends on PPC64
> > 
> > Why not PPC?
> 
> PPC64 seems to a good place to began the consolidation work. This
> patch-set has not been tested for PPC32 currently.

PPC64 is a bad place to start if you want it to be generic, because it
means you'll end up growing dependencies on other things that are PPC64
only.  There are too many arbitrary 32/64 differences as is.

-Scott
Deepthi Dharwar - Aug. 21, 2013, 4:53 a.m.
On 08/19/2013 11:47 PM, Scott Wood wrote:
> On Mon, 2013-08-19 at 15:48 +0530, Deepthi Dharwar wrote:
>> Hi Dongsheng,
>>
>> On 08/19/2013 11:22 AM, Wang Dongsheng-B40534 wrote:
>>> I think we should move the states and handle function to arch/power/platform*
>>> The states and handle function is belong to backend driver, not for this, different platform have different state.
>>> Different platforms to make their own deal with these states.
>>>
>>> I think we cannot put all the status of different platforms and handler in this driver.
>>
>> The idea here is a single powerpc back-end driver, which does a runtime
>> detection of the platform it is running and choose the right
>> idle states table. This was one of outcome of V2 discussion.
> 
> I see a lot more in there than just detecting a platform and choosing a
> driver.
> 
>> I feel there is no harm in keeping the state information in the same
>> file. We do have x86, which has all its variants information in one
>> file. One place will have all the idle consolidated information of
>> all the platform variants. If community does feel, we need to
>> have just the states information in arch specific file, we can do so.
> 
> What actual functionality is common to all powerpc but not common to
> other arches?
> 
>>>> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
>>>> index 0e2cd5c..99ee5d4 100644
>>>> --- a/drivers/cpuidle/Kconfig
>>>> +++ b/drivers/cpuidle/Kconfig
>>>> @@ -42,6 +42,13 @@ config CPU_IDLE_ZYNQ
>>>>  	help
>>>>  	  Select this to enable cpuidle on Xilinx Zynq processors.
>>>>
>>>> +config CPU_IDLE_POWERPC
>>>> +	bool "CPU Idle driver for POWERPC platforms"
>>>> +	depends on PPC64
>>>
>>> Why not PPC?
>>
>> PPC64 seems to a good place to began the consolidation work. This
>> patch-set has not been tested for PPC32 currently.
> 
> PPC64 is a bad place to start if you want it to be generic, because it
> means you'll end up growing dependencies on other things that are PPC64
> only.  There are too many arbitrary 32/64 differences as is.

Hi Scott,

From my understanding, PPC64 includes BOOK3E and BOOK3S archs.
PPC includes PPC32 and PPC64.

It seemed logical to start consolidating at PPC64 as
one does not want to get into 32/64 bit differences.

From your comments above,  I just wanted to clarify if PPC or PPC64 is
bad place to start. If PPC64 is bad place to start, then whats the way
forward ?  Can you please throw some more light on it.

Thanks!
Deepthi



> -Scott
> 
> 
> 
>
Scott Wood - Aug. 21, 2013, 8:08 p.m.
On Wed, 2013-08-21 at 10:23 +0530, Deepthi Dharwar wrote:
> On 08/19/2013 11:47 PM, Scott Wood wrote:
> > On Mon, 2013-08-19 at 15:48 +0530, Deepthi Dharwar wrote:
> >> Hi Dongsheng,
> >>
> >> On 08/19/2013 11:22 AM, Wang Dongsheng-B40534 wrote:
> >>> I think we should move the states and handle function to arch/power/platform*
> >>> The states and handle function is belong to backend driver, not for this, different platform have different state.
> >>> Different platforms to make their own deal with these states.
> >>>
> >>> I think we cannot put all the status of different platforms and handler in this driver.
> >>
> >> The idea here is a single powerpc back-end driver, which does a runtime
> >> detection of the platform it is running and choose the right
> >> idle states table. This was one of outcome of V2 discussion.
> > 
> > I see a lot more in there than just detecting a platform and choosing a
> > driver.
> > 
> >> I feel there is no harm in keeping the state information in the same
> >> file. We do have x86, which has all its variants information in one
> >> file. One place will have all the idle consolidated information of
> >> all the platform variants. If community does feel, we need to
> >> have just the states information in arch specific file, we can do so.
> > 
> > What actual functionality is common to all powerpc but not common to
> > other arches?

No answer?

> >>>> +config CPU_IDLE_POWERPC
> >>>> +	bool "CPU Idle driver for POWERPC platforms"
> >>>> +	depends on PPC64
> >>>
> >>> Why not PPC?
> >>
> >> PPC64 seems to a good place to began the consolidation work. This
> >> patch-set has not been tested for PPC32 currently.
> > 
> > PPC64 is a bad place to start if you want it to be generic, because it
> > means you'll end up growing dependencies on other things that are PPC64
> > only.  There are too many arbitrary 32/64 differences as is.
> 
> Hi Scott,
> 
> From my understanding, PPC64 includes BOOK3E and BOOK3S archs.
> PPC includes PPC32 and PPC64.
> 
> It seemed logical to start consolidating at PPC64 as
> one does not want to get into 32/64 bit differences.

I don't want to "get into" a file that claims to be generic PPC but is
loaded with 64-bit dependencies.

> From your comments above,  I just wanted to clarify if PPC or PPC64 is
> bad place to start. If PPC64 is bad place to start, then whats the way
> forward ?  Can you please throw some more light on it.

The way forward is to give this file a more appropriate name based on
the hardware that it actually targets -- and to refactor it so that the
answer to that question is not complicated.

-Scott
Deepthi Dharwar - Aug. 22, 2013, 5:50 a.m.
On 08/22/2013 01:38 AM, Scott Wood wrote:
> On Wed, 2013-08-21 at 10:23 +0530, Deepthi Dharwar wrote:
>> On 08/19/2013 11:47 PM, Scott Wood wrote:
>>> On Mon, 2013-08-19 at 15:48 +0530, Deepthi Dharwar wrote:
>>>> Hi Dongsheng,
>>>>
>>>> On 08/19/2013 11:22 AM, Wang Dongsheng-B40534 wrote:
>>>>> I think we should move the states and handle function to arch/power/platform*
>>>>> The states and handle function is belong to backend driver, not for this, different platform have different state.
>>>>> Different platforms to make their own deal with these states.
>>>>>
>>>>> I think we cannot put all the status of different platforms and handler in this driver.
>>>>
>>>> The idea here is a single powerpc back-end driver, which does a runtime
>>>> detection of the platform it is running and choose the right
>>>> idle states table. This was one of outcome of V2 discussion.
>>>
>>> I see a lot more in there than just detecting a platform and choosing a
>>> driver.
>>>
>>>> I feel there is no harm in keeping the state information in the same
>>>> file. We do have x86, which has all its variants information in one
>>>> file. One place will have all the idle consolidated information of
>>>> all the platform variants. If community does feel, we need to
>>>> have just the states information in arch specific file, we can do so.
>>>
>>> What actual functionality is common to all powerpc but not common to
>>> other arches?
> 

The functionality here is idle states on powerpc  like the snooze loop
that is common.
Also, the basic registration of the driver, hotplug notifier etc for
powerpc.

> 
>>>>>> +config CPU_IDLE_POWERPC
>>>>>> +	bool "CPU Idle driver for POWERPC platforms"
>>>>>> +	depends on PPC64
>>>>>
>>>>> Why not PPC?
>>>>
>>>> PPC64 seems to a good place to began the consolidation work. This
>>>> patch-set has not been tested for PPC32 currently.
>>>
>>> PPC64 is a bad place to start if you want it to be generic, because it
>>> means you'll end up growing dependencies on other things that are PPC64
>>> only.  There are too many arbitrary 32/64 differences as is.
>>
>> Hi Scott,
>>
>> From my understanding, PPC64 includes BOOK3E and BOOK3S archs.
>> PPC includes PPC32 and PPC64.
>>
>> It seemed logical to start consolidating at PPC64 as
>> one does not want to get into 32/64 bit differences.
> 
> I don't want to "get into" a file that claims to be generic PPC but is
> loaded with 64-bit dependencies.
> 
>> From your comments above,  I just wanted to clarify if PPC or PPC64 is
>> bad place to start. If PPC64 is bad place to start, then whats the way
>> forward ?  Can you please throw some more light on it.
> 
> The way forward is to give this file a more appropriate name based on
> the hardware that it actually targets -- and to refactor it so that the
> answer to that question is not complicated.

Sure, thanks.
Our idea was to have POWER archs idle states merged at the first go.
Only that is what is enabled in the current version (V4 posted out)
( Code is enabled for PSERIES and POWERNV only)
If needed, other POWERPC archs might benefit by extending the same
driver, that is why it is named cpuidle-powerpc.c

But if having cpuidle backend-driver separately for other powerpc arcs
makes sense such that each one have their own state information etc
then it makes sense to name the files as cpuidle-power.c,
cpuilde-ppc32.c and so on.

Regards,
Deepthi


> 
> -Scott
> 
> 
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
> 
>
Benjamin Herrenschmidt - Aug. 22, 2013, 5:58 a.m.
On Thu, 2013-08-22 at 11:20 +0530, Deepthi Dharwar wrote:
> But if having cpuidle backend-driver separately for other powerpc arcs
> makes sense such that each one have their own state information etc
> then it makes sense to name the files as cpuidle-power.c,
> cpuilde-ppc32.c and so on.

If by "power" you mean IBM POWER machines/CPUs, then make it
cpuidle-ibm-power or cpuidle-book3s64 maybe to clarify what families it
affects.

Cheers
Ben.
Deepthi Dharwar - Aug. 22, 2013, 6:41 a.m.
On 08/22/2013 11:28 AM, Benjamin Herrenschmidt wrote:
> On Thu, 2013-08-22 at 11:20 +0530, Deepthi Dharwar wrote:
>> But if having cpuidle backend-driver separately for other powerpc arcs
>> makes sense such that each one have their own state information etc
>> then it makes sense to name the files as cpuidle-power.c,
>> cpuilde-ppc32.c and so on.
> 
> If by "power" you mean IBM POWER machines/CPUs, then make it
> cpuidle-ibm-power or cpuidle-book3s64 maybe to clarify what families it
> affects.

Sure. Thanks :)

Regards,
Deepthi


> Cheers
> Ben.
> 
> 
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
> 
>
Scott Wood - Aug. 22, 2013, 9:24 p.m.
On Thu, 2013-08-22 at 11:20 +0530, Deepthi Dharwar wrote:
> On 08/22/2013 01:38 AM, Scott Wood wrote:
> > On Wed, 2013-08-21 at 10:23 +0530, Deepthi Dharwar wrote:
> >> On 08/19/2013 11:47 PM, Scott Wood wrote:
> >>> What actual functionality is common to all powerpc but not common to
> >>> other arches?
> > 
> 
> The functionality here is idle states on powerpc  like the snooze loop
> that is common.
> Also, the basic registration of the driver, hotplug notifier etc for
> powerpc.

The snooze loop uses things like SPRN_PURR, get_lppaca(), and CTRL which
aren't common to all PPC (they might be common to all book3s64).  I also
don't see any hook for the low power mode entry -- is "snooze" just a
busy loop plus the de-emphasis stuff like HMT and CTRL[RUN]?  I'm not
familiar with the term "snooze" in this context.  I don't think we'd use
anything like that on our chips; we'd always at least "wait" or "doze"
depending on the chip.

It's not clear what is powerpc-specific about the notifier -- perhaps it
should go in drivers/cpuidle/.

> > The way forward is to give this file a more appropriate name based on
> > the hardware that it actually targets -- and to refactor it so that the
> > answer to that question is not complicated.
> 
> Sure, thanks.
> Our idea was to have POWER archs idle states merged at the first go.
> Only that is what is enabled in the current version (V4 posted out)
> ( Code is enabled for PSERIES and POWERNV only)
> If needed, other POWERPC archs might benefit by extending the same
> driver, that is why it is named cpuidle-powerpc.c
> 
> But if having cpuidle backend-driver separately for other powerpc arcs
> makes sense such that each one have their own state information etc
> then it makes sense to name the files as cpuidle-power.c,
> cpuilde-ppc32.c and so on.

Thanks.

-Scott
Deepthi Dharwar - Aug. 23, 2013, 10:11 a.m.
On 08/23/2013 02:54 AM, Scott Wood wrote:
> On Thu, 2013-08-22 at 11:20 +0530, Deepthi Dharwar wrote:
>> On 08/22/2013 01:38 AM, Scott Wood wrote:
>>> On Wed, 2013-08-21 at 10:23 +0530, Deepthi Dharwar wrote:
>>>> On 08/19/2013 11:47 PM, Scott Wood wrote:
>>>>> What actual functionality is common to all powerpc but not common to
>>>>> other arches?
>>>
>>
>> The functionality here is idle states on powerpc  like the snooze loop
>> that is common.
>> Also, the basic registration of the driver, hotplug notifier etc for
>> powerpc.
> 
> The snooze loop uses things like SPRN_PURR, get_lppaca(), and CTRL which
> aren't common to all PPC (they might be common to all book3s64).  I also
> don't see any hook for the low power mode entry -- is "snooze" just a
> busy loop plus the de-emphasis stuff like HMT and CTRL[RUN]?  I'm not
> familiar with the term "snooze" in this context.  I don't think we'd use
> anything like that on our chips; we'd always at least "wait" or "doze"
> depending on the chip.
>

Duly noted. Lot of stuff are common across book3s64. So my later
versions of this patchset does just that. (V5 posted out yesterday).
The driver is common only to IBM-POWER platform. Other PPC variants
can have their own driver.


> It's not clear what is powerpc-specific about the notifier -- perhaps it
> should go in drivers/cpuidle/.

Currently all the arcs have their own hotplug notifier. Unifying this
across all archs is a challenge that needs to be taken going forward.

Thanks for the review.
Regards,
Deepthi


>>> The way forward is to give this file a more appropriate name based on
>>> the hardware that it actually targets -- and to refactor it so that the
>>> answer to that question is not complicated.
>>
>> Sure, thanks.
>> Our idea was to have POWER archs idle states merged at the first go.
>> Only that is what is enabled in the current version (V4 posted out)
>> ( Code is enabled for PSERIES and POWERNV only)
>> If needed, other POWERPC archs might benefit by extending the same
>> driver, that is why it is named cpuidle-powerpc.c
>>
>> But if having cpuidle backend-driver separately for other powerpc arcs
>> makes sense such that each one have their own state information etc
>> then it makes sense to name the files as cpuidle-power.c,
>> cpuilde-ppc32.c and so on.
> 
> Thanks.
> 
> -Scott
> 
> 
> 
> _______________________________________________
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> Linuxppc-dev@lists.ozlabs.org
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Patch

diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 77c91e7..7bd83ff 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -175,6 +175,29 @@  extern void setup_paca(struct paca_struct *new_paca);
 extern void allocate_pacas(void);
 extern void free_unused_pacas(void);
 
+#ifdef CONFIG_PPC_BOOK3S
+#define get_lppaca_is_shared_proc()  get_paca()->lppaca_ptr->shared_proc
+static inline void set_lppaca_idle(u8  idle)
+{
+	get_paca()->lppaca_ptr->idle = idle;
+}
+
+static inline void add_lppaca_wait_state(u64 cycles)
+{
+	get_paca()->lppaca_ptr->wait_state_cycles += cycles;
+}
+
+static inline void set_lppaca_donate_dedicated_cpu(u8 value)
+{
+	get_paca()->lppaca_ptr->donate_dedicated_cpu = value;
+}
+#else
+#define get_lppaca_is_shared_proc()	-1
+static inline void set_lppaca_idle(u8 idle) { }
+static inline void  add_lppaca_wait_state(u64 cycles) { }
+static inline void  set_lppaca_donate_dedicated_cpu(u8 value) { }
+#endif
+
 #else /* CONFIG_PPC64 */
 
 static inline void allocate_pacas(void) { };
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index e378ccc..5f57c56 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -430,7 +430,7 @@  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_POWERPC
 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 8ae0103..4b22379 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
 
 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
deleted file mode 100644
index c905b99..0000000
--- a/arch/powerpc/platforms/pseries/processor_idle.c
+++ /dev/null
@@ -1,360 +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)
-{
-	get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr;
-	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 (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;
-	}
-
-	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 0e2cd5c..99ee5d4 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -42,6 +42,13 @@  config CPU_IDLE_ZYNQ
 	help
 	  Select this to enable cpuidle on Xilinx Zynq processors.
 
+config CPU_IDLE_POWERPC
+	bool "CPU Idle driver for POWERPC platforms"
+	depends on PPC64
+	default y
+        help
+          Select this option to enable processor idle state management
+	  for POWERPC platform.
 endif
 
 config ARCH_NEEDS_CPU_IDLE_COUPLED
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 8767a7b..d12e205 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -8,3 +8,5 @@  obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
 obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o
 obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o
 obj-$(CONFIG_CPU_IDLE_ZYNQ) += cpuidle-zynq.o
+
+obj-$(CONFIG_CPU_IDLE_POWERPC) += cpuidle-powerpc.o
diff --git a/drivers/cpuidle/cpuidle-powerpc.c b/drivers/cpuidle/cpuidle-powerpc.c
new file mode 100644
index 0000000..5756085
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-powerpc.c
@@ -0,0 +1,361 @@ 
+/*
+ *  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 powerpc_idle_driver = {
+	.name             = "powerpc_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 *powerpc_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.
+	 */
+	set_lppaca_idle(1);
+}
+
+static inline void idle_loop_epilog(unsigned long in_purr)
+{
+	add_lppaca_wait_state(mfspr(SPRN_PURR) - in_purr);
+	set_lppaca_idle(0);
+}
+
+static int snooze_loop(struct cpuidle_device *dev,
+			struct cpuidle_driver *drv,
+			int index)
+{
+	unsigned long in_purr;
+
+	idle_loop_prolog(&in_purr);
+	local_irq_enable();
+	set_thread_flag(TIF_POLLING_NRFLAG);
+
+	while (!need_resched()) {
+		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);
+	set_lppaca_donate_dedicated_cpu(1);
+
+	ppc64_runlatch_off();
+	HMT_medium();
+	check_and_cede_processor();
+
+	set_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 powerpc_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(powerpc_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 = powerpc_cpuidle_add_cpu_notifier,
+};
+
+/*
+ * powerpc_cpuidle_driver_init()
+ */
+static int powerpc_cpuidle_driver_init(void)
+{
+	int idle_state;
+	struct cpuidle_driver *drv = &powerpc_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;
+}
+
+/* powerpc_idle_devices_uninit(void)
+ * unregister cpuidle devices and de-allocate memory
+ */
+static void powerpc_idle_devices_uninit(void)
+{
+	int i;
+	struct cpuidle_device *dev;
+
+	for_each_possible_cpu(i) {
+		dev = per_cpu_ptr(powerpc_cpuidle_devices, i);
+		cpuidle_unregister_device(dev);
+	}
+
+	free_percpu(powerpc_cpuidle_devices);
+	return;
+}
+
+/* powerpc_idle_devices_init()
+ * allocate, initialize and register cpuidle device
+ */
+static int powerpc_idle_devices_init(void)
+{
+	int i;
+	struct cpuidle_driver *drv = &powerpc_idle_driver;
+	struct cpuidle_device *dev;
+
+	powerpc_cpuidle_devices = alloc_percpu(struct cpuidle_device);
+	if (powerpc_cpuidle_devices == NULL)
+		return -ENOMEM;
+
+	for_each_possible_cpu(i) {
+		dev = per_cpu_ptr(powerpc_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;
+}
+
+/*
+ * powerpc_idle_probe()
+ * Choose state table for shared versus dedicated partition
+ */
+static int powerpc_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 "powerpc processor idle disabled.\n");
+		return -EPERM;
+	}
+
+	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
+		if (get_lppaca_is_shared_proc() == 1)
+			cpuidle_state_table = shared_states;
+		else if (get_lppaca_is_shared_proc() == 0)
+			cpuidle_state_table = dedicated_states;
+	} else
+		return -ENODEV;
+
+	return 0;
+}
+
+static int __init powerpc_processor_idle_init(void)
+{
+	int retval;
+
+	retval = powerpc_idle_probe();
+	if (retval)
+		return retval;
+
+	powerpc_cpuidle_driver_init();
+	retval = cpuidle_register_driver(&powerpc_idle_driver);
+	if (retval) {
+		printk(KERN_DEBUG "Registration of powerpc driver failed.\n");
+		return retval;
+	}
+
+	retval = powerpc_idle_devices_init();
+	if (retval) {
+		powerpc_idle_devices_uninit();
+		cpuidle_unregister_driver(&powerpc_idle_driver);
+		return retval;
+	}
+
+	register_cpu_notifier(&setup_hotplug_notifier);
+	printk(KERN_DEBUG "powerpc_idle_driver registered\n");
+
+	return 0;
+}
+
+static void __exit powerpc_processor_idle_exit(void)
+{
+
+	unregister_cpu_notifier(&setup_hotplug_notifier);
+	powerpc_idle_devices_uninit();
+	cpuidle_unregister_driver(&powerpc_idle_driver);
+
+	return;
+}
+
+module_init(powerpc_processor_idle_init);
+module_exit(powerpc_processor_idle_exit);
+
+MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("Cpuidle driver for powerpc");
+MODULE_LICENSE("GPL");