arch/powerpc/platforms/pseries/processor_idle.c - maze/linux - Git at Google

 /*
  *  processor_idle - idle state cpuidle driver.
  *  Adapted from drivers/idle/intel_idle.c and
  *  drivers/acpi/processor_idle.c
  *
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/moduleparam.h>
 #include <linux/cpuidle.h>
 #include <linux/cpu.h>

 #include <asm/paca.h>
 #include <asm/reg.h>
 #include <asm/machdep.h>
 #include <asm/firmware.h>
 #include <asm/runlatch.h>

 #include "plpar_wrappers.h"
 #include "pseries.h"

 struct cpuidle_driver pseries_idle_driver = {
 	.name =		"pseries_idle",
 	.owner =	THIS_MODULE,
 };

 #define MAX_IDLE_STATE_COUNT	2

 static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
 static struct cpuidle_device __percpu *pseries_cpuidle_devices;
 static struct cpuidle_state *cpuidle_state_table;

 void update_smt_snooze_delay(int snooze)
 {
 	struct cpuidle_driver *drv = cpuidle_get_driver();
 	if (drv)
 		drv->states[0].target_residency = snooze;
 }

 static inline void idle_loop_prolog(unsigned long *in_purr, ktime_t *kt_before)
 {

 	*kt_before = ktime_get_real();
 	*in_purr = mfspr(SPRN_PURR);
 	/*
 	 * Indicate to the HV that we are idle. Now would be
 	 * a good time to find other work to dispatch.
 	 */
 	get_lppaca()->idle = 1;
 }

 static inline  s64 idle_loop_epilog(unsigned long in_purr, ktime_t kt_before)
 {
 	get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr;
 	get_lppaca()->idle = 0;

 	return ktime_to_us(ktime_sub(ktime_get_real(), kt_before));
 }

 static int snooze_loop(struct cpuidle_device *dev,
 			struct cpuidle_driver *drv,
 			int index)
 {
 	unsigned long in_purr;
 	ktime_t kt_before;
 	unsigned long start_snooze;
 	long snooze = drv->states[0].target_residency;

 	idle_loop_prolog(&in_purr, &kt_before);

 	if (snooze) {
 		start_snooze = get_tb() + snooze * tb_ticks_per_usec;
 		local_irq_enable();
 		set_thread_flag(TIF_POLLING_NRFLAG);

 		while ((snooze < 0) || (get_tb() < start_snooze)) {
 			if (need_resched() || cpu_is_offline(dev->cpu))
 				goto out;
 			ppc64_runlatch_off();
 			HMT_low();
 			HMT_very_low();
 		}

 		HMT_medium();
 		clear_thread_flag(TIF_POLLING_NRFLAG);
 		smp_mb();
 		local_irq_disable();
 	}

 out:
 	HMT_medium();
 	dev->last_residency =
 		(int)idle_loop_epilog(in_purr, kt_before);
 	return index;
 }

 static void check_and_cede_processor(void)
 {
 	/*
 	 * Interrupts are soft-disabled at this point,
 	 * but not hard disabled. So an interrupt might have
 	 * occurred before entering NAP, and would be potentially
 	 * lost (edge events, decrementer events, etc...) unless
 	 * we first hard disable then check.
 	 */
 	hard_irq_disable();
 	if (!lazy_irq_pending())
 		cede_processor();
 }

 static int dedicated_cede_loop(struct cpuidle_device *dev,
 				struct cpuidle_driver *drv,
 				int index)
 {
 	unsigned long in_purr;
 	ktime_t kt_before;

 	idle_loop_prolog(&in_purr, &kt_before);
 	get_lppaca()->donate_dedicated_cpu = 1;

 	ppc64_runlatch_off();
 	HMT_medium();
 	check_and_cede_processor();

 	get_lppaca()->donate_dedicated_cpu = 0;
 	dev->last_residency =
 		(int)idle_loop_epilog(in_purr, kt_before);
 	return index;
 }

 static int shared_cede_loop(struct cpuidle_device *dev,
 			struct cpuidle_driver *drv,
 			int index)
 {
 	unsigned long in_purr;
 	ktime_t kt_before;

 	idle_loop_prolog(&in_purr, &kt_before);

 	/*
 	 * Yield the processor to the hypervisor.  We return if
 	 * an external interrupt occurs (which are driven prior
 	 * to returning here) or if a prod occurs from another
 	 * processor. When returning here, external interrupts
 	 * are enabled.
 	 */
 	check_and_cede_processor();

 	dev->last_residency =
 		(int)idle_loop_epilog(in_purr, kt_before);
 	return index;
 }

 /*
  * States for dedicated partition case.
  */
 static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = {
 	{ /* Snooze */
 		.name = "snooze",
 		.desc = "snooze",
 		.flags = CPUIDLE_FLAG_TIME_VALID,
 		.exit_latency = 0,
 		.target_residency = 0,
 		.enter = &snooze_loop },
 	{ /* CEDE */
 		.name = "CEDE",
 		.desc = "CEDE",
 		.flags = CPUIDLE_FLAG_TIME_VALID,
 		.exit_latency = 1,
 		.target_residency = 10,
 		.enter = &dedicated_cede_loop },
 };

 /*
  * States for shared partition case.
  */
 static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
 	{ /* Shared Cede */
 		.name = "Shared Cede",
 		.desc = "Shared Cede",
 		.flags = CPUIDLE_FLAG_TIME_VALID,
 		.exit_latency = 0,
 		.target_residency = 0,
 		.enter = &shared_cede_loop },
 };

 int pseries_notify_cpuidle_add_cpu(int cpu)
 {
 	struct cpuidle_device *dev =
 			per_cpu_ptr(pseries_cpuidle_devices, cpu);
 	if (dev && cpuidle_get_driver()) {
 		cpuidle_disable_device(dev);
 		cpuidle_enable_device(dev);
 	}
 	return 0;
 }

 /*
  * pseries_cpuidle_driver_init()
  */
 static int pseries_cpuidle_driver_init(void)
 {
 	int idle_state;
 	struct cpuidle_driver *drv = &pseries_idle_driver;

 	drv->state_count = 0;

 	for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) {

 		if (idle_state > max_idle_state)
 			break;

 		/* is the state not enabled? */
 		if (cpuidle_state_table[idle_state].enter == NULL)
 			continue;

 		drv->states[drv->state_count] =	/* structure copy */
 			cpuidle_state_table[idle_state];

 		if (cpuidle_state_table == dedicated_states)
 			drv->states[drv->state_count].target_residency =
 				__get_cpu_var(smt_snooze_delay);

 		drv->state_count += 1;
 	}

 	return 0;
 }

 /* pseries_idle_devices_uninit(void)
  * unregister cpuidle devices and de-allocate memory
  */
 static void pseries_idle_devices_uninit(void)
 {
 	int i;
 	struct cpuidle_device *dev;

 	for_each_possible_cpu(i) {
 		dev = per_cpu_ptr(pseries_cpuidle_devices, i);
 		cpuidle_unregister_device(dev);
 	}

 	free_percpu(pseries_cpuidle_devices);
 	return;
 }

 /* pseries_idle_devices_init()
  * allocate, initialize and register cpuidle device
  */
 static int pseries_idle_devices_init(void)
 {
 	int i;
 	struct cpuidle_driver *drv = &pseries_idle_driver;
 	struct cpuidle_device *dev;

 	pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device);
 	if (pseries_cpuidle_devices == NULL)
 		return -ENOMEM;

 	for_each_possible_cpu(i) {
 		dev = per_cpu_ptr(pseries_cpuidle_devices, i);
 		dev->state_count = drv->state_count;
 		dev->cpu = i;
 		if (cpuidle_register_device(dev)) {
 			printk(KERN_DEBUG \
 				"cpuidle_register_device %d failed!\n", i);
 			return -EIO;
 		}
 	}

 	return 0;
 }

 /*
  * pseries_idle_probe()
  * Choose state table for shared versus dedicated partition
  */
 static int pseries_idle_probe(void)
 {

 	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
 		return -ENODEV;

 	if (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;
 	}

 	printk(KERN_DEBUG "pseries_idle_driver registered\n");

 	return 0;
 }

 static void __exit pseries_processor_idle_exit(void)
 {

 	pseries_idle_devices_uninit();
 	cpuidle_unregister_driver(&pseries_idle_driver);

 	return;
 }

 module_init(pseries_processor_idle_init);
 module_exit(pseries_processor_idle_exit);

 MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>");
 MODULE_DESCRIPTION("Cpuidle driver for POWER");
 MODULE_LICENSE("GPL");
	/*
	* processor_idle - idle state cpuidle driver.
	* Adapted from drivers/idle/intel_idle.c and
	* drivers/acpi/processor_idle.c
	*
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/moduleparam.h>
	#include <linux/cpuidle.h>
	#include <linux/cpu.h>

	#include <asm/paca.h>
	#include <asm/reg.h>
	#include <asm/machdep.h>
	#include <asm/firmware.h>
	#include <asm/runlatch.h>

	#include "plpar_wrappers.h"
	#include "pseries.h"

	struct cpuidle_driver pseries_idle_driver = {
	.name = "pseries_idle",
	.owner = THIS_MODULE,
	};

	#define MAX_IDLE_STATE_COUNT 2

	static int max_idle_state = MAX_IDLE_STATE_COUNT - 1;
	static struct cpuidle_device __percpu *pseries_cpuidle_devices;
	static struct cpuidle_state *cpuidle_state_table;

	void update_smt_snooze_delay(int snooze)
	{
	struct cpuidle_driver *drv = cpuidle_get_driver();
	if (drv)
	drv->states[0].target_residency = snooze;
	}

	static inline void idle_loop_prolog(unsigned long in_purr, ktime_t kt_before)
	{

	*kt_before = ktime_get_real();
	*in_purr = mfspr(SPRN_PURR);
	/*
	* Indicate to the HV that we are idle. Now would be
	* a good time to find other work to dispatch.
	*/
	get_lppaca()->idle = 1;
	}

	static inline s64 idle_loop_epilog(unsigned long in_purr, ktime_t kt_before)
	{
	get_lppaca()->wait_state_cycles += mfspr(SPRN_PURR) - in_purr;
	get_lppaca()->idle = 0;

	return ktime_to_us(ktime_sub(ktime_get_real(), kt_before));
	}

	static int snooze_loop(struct cpuidle_device *dev,
	struct cpuidle_driver *drv,
	int index)
	{
	unsigned long in_purr;
	ktime_t kt_before;
	unsigned long start_snooze;
	long snooze = drv->states[0].target_residency;

	idle_loop_prolog(&in_purr, &kt_before);

	if (snooze) {
	start_snooze = get_tb() + snooze * tb_ticks_per_usec;
	local_irq_enable();
	set_thread_flag(TIF_POLLING_NRFLAG);

	while ((snooze < 0) \|\| (get_tb() < start_snooze)) {
	if (need_resched() \|\| cpu_is_offline(dev->cpu))
	goto out;
	ppc64_runlatch_off();
	HMT_low();
	HMT_very_low();
	}

	HMT_medium();
	clear_thread_flag(TIF_POLLING_NRFLAG);
	smp_mb();
	local_irq_disable();
	}

	out:
	HMT_medium();
	dev->last_residency =
	(int)idle_loop_epilog(in_purr, kt_before);
	return index;
	}

	static void check_and_cede_processor(void)
	{
	/*
	* Interrupts are soft-disabled at this point,
	* but not hard disabled. So an interrupt might have
	* occurred before entering NAP, and would be potentially
	* lost (edge events, decrementer events, etc...) unless
	* we first hard disable then check.
	*/
	hard_irq_disable();
	if (!lazy_irq_pending())
	cede_processor();
	}

	static int dedicated_cede_loop(struct cpuidle_device *dev,
	struct cpuidle_driver *drv,
	int index)
	{
	unsigned long in_purr;
	ktime_t kt_before;

	idle_loop_prolog(&in_purr, &kt_before);
	get_lppaca()->donate_dedicated_cpu = 1;

	ppc64_runlatch_off();
	HMT_medium();
	check_and_cede_processor();

	get_lppaca()->donate_dedicated_cpu = 0;
	dev->last_residency =
	(int)idle_loop_epilog(in_purr, kt_before);
	return index;
	}

	static int shared_cede_loop(struct cpuidle_device *dev,
	struct cpuidle_driver *drv,
	int index)
	{
	unsigned long in_purr;
	ktime_t kt_before;

	idle_loop_prolog(&in_purr, &kt_before);

	/*
	* Yield the processor to the hypervisor. We return if
	* an external interrupt occurs (which are driven prior
	* to returning here) or if a prod occurs from another
	* processor. When returning here, external interrupts
	* are enabled.
	*/
	check_and_cede_processor();

	dev->last_residency =
	(int)idle_loop_epilog(in_purr, kt_before);
	return index;
	}

	/*
	* States for dedicated partition case.
	*/
	static struct cpuidle_state dedicated_states[MAX_IDLE_STATE_COUNT] = {
	{ /* Snooze */
	.name = "snooze",
	.desc = "snooze",
	.flags = CPUIDLE_FLAG_TIME_VALID,
	.exit_latency = 0,
	.target_residency = 0,
	.enter = &snooze_loop },
	{ /* CEDE */
	.name = "CEDE",
	.desc = "CEDE",
	.flags = CPUIDLE_FLAG_TIME_VALID,
	.exit_latency = 1,
	.target_residency = 10,
	.enter = &dedicated_cede_loop },
	};

	/*
	* States for shared partition case.
	*/
	static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
	{ /* Shared Cede */
	.name = "Shared Cede",
	.desc = "Shared Cede",
	.flags = CPUIDLE_FLAG_TIME_VALID,
	.exit_latency = 0,
	.target_residency = 0,
	.enter = &shared_cede_loop },
	};

	int pseries_notify_cpuidle_add_cpu(int cpu)
	{
	struct cpuidle_device *dev =
	per_cpu_ptr(pseries_cpuidle_devices, cpu);
	if (dev && cpuidle_get_driver()) {
	cpuidle_disable_device(dev);
	cpuidle_enable_device(dev);
	}
	return 0;
	}

	/*
	* pseries_cpuidle_driver_init()
	*/
	static int pseries_cpuidle_driver_init(void)
	{
	int idle_state;
	struct cpuidle_driver *drv = &pseries_idle_driver;

	drv->state_count = 0;

	for (idle_state = 0; idle_state < MAX_IDLE_STATE_COUNT; ++idle_state) {

	if (idle_state > max_idle_state)
	break;

	/* is the state not enabled? */
	if (cpuidle_state_table[idle_state].enter == NULL)
	continue;

	drv->states[drv->state_count] = /* structure copy */
	cpuidle_state_table[idle_state];

	if (cpuidle_state_table == dedicated_states)
	drv->states[drv->state_count].target_residency =
	__get_cpu_var(smt_snooze_delay);

	drv->state_count += 1;
	}

	return 0;
	}

	/* pseries_idle_devices_uninit(void)
	* unregister cpuidle devices and de-allocate memory
	*/
	static void pseries_idle_devices_uninit(void)
	{
	int i;
	struct cpuidle_device *dev;

	for_each_possible_cpu(i) {
	dev = per_cpu_ptr(pseries_cpuidle_devices, i);
	cpuidle_unregister_device(dev);
	}

	free_percpu(pseries_cpuidle_devices);
	return;
	}

	/* pseries_idle_devices_init()
	* allocate, initialize and register cpuidle device
	*/
	static int pseries_idle_devices_init(void)
	{
	int i;
	struct cpuidle_driver *drv = &pseries_idle_driver;
	struct cpuidle_device *dev;

	pseries_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	if (pseries_cpuidle_devices == NULL)
	return -ENOMEM;

	for_each_possible_cpu(i) {
	dev = per_cpu_ptr(pseries_cpuidle_devices, i);
	dev->state_count = drv->state_count;
	dev->cpu = i;
	if (cpuidle_register_device(dev)) {
	printk(KERN_DEBUG \
	"cpuidle_register_device %d failed!\n", i);
	return -EIO;
	}
	}

	return 0;
	}

	/*
	* pseries_idle_probe()
	* Choose state table for shared versus dedicated partition
	*/
	static int pseries_idle_probe(void)
	{

	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
	return -ENODEV;

	if (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;
	}

	printk(KERN_DEBUG "pseries_idle_driver registered\n");

	return 0;
	}

	static void __exit pseries_processor_idle_exit(void)
	{

	pseries_idle_devices_uninit();
	cpuidle_unregister_driver(&pseries_idle_driver);

	return;
	}

	module_init(pseries_processor_idle_init);
	module_exit(pseries_processor_idle_exit);

	MODULE_AUTHOR("Deepthi Dharwar <deepthi@linux.vnet.ibm.com>");
	MODULE_DESCRIPTION("Cpuidle driver for POWER");
	MODULE_LICENSE("GPL");