Subject: Re: [PATCH V4 3/5] powerpc/cpuidle: Generic powerpc backend cpuidle driver.

From: Deepthi Dharwar <[email-masked]>
Date: Fri, 23 Aug 2013 15:49:49 +0530

Hi Bartlomiej,

Thanks for the review.

On 08/22/2013 04:26 PM, Bartlomiej Zolnierkiewicz wrote:
> 
> Hi,
> 
> On Thursday, August 22, 2013 11:00:29 AM Deepthi Dharwar wrote:
>> 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 both powernv and pseries.
>>
>> 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 in the future. This removes a lot of code duplicacy,
>> making the code elegant.
> 
> This patch mixes the code movement with the actual code changes which is
> not a good practice as it makes review more difficult and is generally bad
> from the long term maintainance POV.
> 
> Please split this patch on code movement and code changes parts.

Sure. I shall do so.

> V4 of this patch now also seems to contain changes which I posted on
> Tuesday as a part of dev->state_count removal patchset:
> 
> http://permalink.gmane.org/gmane.linux.power-management.general/37392
> http://permalink.gmane.org/gmane.linux.power-management.general/37393
> 
> so some work probably got duplicated. :(
> 

Sorry about that. I have been re-writing this driver over the last few
weeks and this cleanup was on my to-do list since V1 as pointed out by
Daniel. I have missed seeing your cleanup.

Thanks for patch !

Regards,
Deepthi

> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
>> Signed-off-by: Deepthi Dharwar <[email-masked]>
>> ---
>>  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               |  304 +++++++++++++++++++
>>  8 files changed, 337 insertions(+), 371 deletions(-)
>>  delete mode 100644 arch/powerpc/platforms/pseries/processor_idle.c
>>  create mode 100644 drivers/cpuidle/cpuidle-powerpc.c
>>
>> 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 <[email-masked]>");
>> -MODULE_DESCRIPTION("Cpuidle driver for POWER");
>> -MODULE_LICENSE("GPL");
>> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
>> index 0e2cd5c..53ce03d 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 PPC_PSERIES || PPC_POWERNV
>> +	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..3662aba
>> --- /dev/null
>> +++ b/drivers/cpuidle/cpuidle-powerpc.c
>> @@ -0,0 +1,304 @@
>> +/*
>> + *  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_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(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_probe()
>> + * Choose state table for shared versus dedicated partition
>> + */
>> +static int powerpc_idle_probe(void)
>> +{
>> +
>> +	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(&powerpc_idle_driver, NULL);
>> +	if (retval) {
>> +		printk(KERN_DEBUG "Registration of powerpc driver failed.\n");
>> +		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);
>> +	cpuidle_unregister(&powerpc_idle_driver);
>> +	return;
>> +}
>> +
>> +module_init(powerpc_processor_idle_init);
>> +module_exit(powerpc_processor_idle_exit);
>> +
>> +MODULE_AUTHOR("Deepthi Dharwar <[email-masked]>");
>> +MODULE_DESCRIPTION("Cpuidle driver for powerpc");
>> +MODULE_LICENSE("GPL");
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