powerpc/cpuidle: cpuidle driver for pSeries (707827f3) · Commits · 戴 / test

arch/powerpc/include/asm/system.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -223,6 +223,14 @@ extern void *zalloc_maybe_bootmem(size_t size, gfp_t mask);
		extern int powersave_nap; /* set if nap mode can be used in idle loop */
		void cpu_idle_wait(void);

		#ifdef CONFIG_PSERIES_IDLE
		extern void update_smt_snooze_delay(int snooze);
		extern int pseries_notify_cpuidle_add_cpu(int cpu);
		#else
		static inline void update_smt_snooze_delay(int snooze) {}
		static inline int pseries_notify_cpuidle_add_cpu(int cpu) { return 0; }
		#endif

		/*
		* Atomic exchange
		*

arch/powerpc/kernel/sysfs.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#include <asm/machdep.h>
		#include <asm/smp.h>
		#include <asm/pmc.h>
		#include <asm/system.h>

		#include "cacheinfo.h"

		@@ -51,6 +52,7 @@ static ssize_t store_smt_snooze_delay(struct sys_device *dev,
		return -EINVAL;

		per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
		update_smt_snooze_delay(snooze);

		return count;
		}

arch/powerpc/platforms/pseries/Kconfig

+9 −0

Original line number	Diff line number	Diff line
		@@ -120,3 +120,12 @@ config DTL
		which are accessible through a debugfs file.

		Say N if you are unsure.

		config PSERIES_IDLE
		tristate "Cpuidle driver for pSeries platforms"
		depends on CPU_IDLE
		depends on PPC_PSERIES
		default y
		help
		Select this option to enable processor idle state management
		through cpuidle subsystem.

arch/powerpc/platforms/pseries/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@ obj-$(CONFIG_PHYP_DUMP) += phyp_dump.o
		obj-$(CONFIG_CMM) += cmm.o
		obj-$(CONFIG_DTL) += dtl.o
		obj-$(CONFIG_IO_EVENT_IRQ) += io_event_irq.o
		obj-$(CONFIG_PSERIES_IDLE) += processor_idle.o

		ifeq ($(CONFIG_PPC_PSERIES),y)
		obj-$(CONFIG_SUSPEND) += suspend.o

arch/powerpc/platforms/pseries/processor_idle.c

0 → 100644

+326 −0

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

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

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

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

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

		#define MAX_IDLE_STATE_COUNT 2

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

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

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

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

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

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

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

		idle_loop_prolog(&in_purr, &kt_before);

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

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

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

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

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

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

		ppc64_runlatch_off();
		HMT_medium();
		cede_processor();

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

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

		idle_loop_prolog(&in_purr, &kt_before);

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

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

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

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

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

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

		drv->state_count = 0;

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

		if (idle_state > max_idle_state)
		break;

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

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

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

		drv->state_count += 1;
		}

		return 0;
		}

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

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

		free_percpu(pseries_cpuidle_devices);
		return;
		}

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

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

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

		return 0;
		}

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

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

		if (max_idle_state == 0) {
		printk(KERN_DEBUG "pseries processor idle disabled.\n");
		return -EPERM;
		}

		if (get_lppaca()->shared_proc)
		cpuidle_state_table = shared_states;
		else
		cpuidle_state_table = dedicated_states;

		return 0;
		}

		static int __init pseries_processor_idle_init(void)
		{
		int retval;

		retval = pseries_idle_probe();
		if (retval)
		return retval;

		pseries_cpuidle_driver_init();
		retval = cpuidle_register_driver(&pseries_idle_driver);
		if (retval) {
		printk(KERN_DEBUG "Registration of pseries driver failed.\n");
		return retval;
		}

		retval = pseries_idle_devices_init();
		if (retval) {
		pseries_idle_devices_uninit();
		cpuidle_unregister_driver(&pseries_idle_driver);
		return retval;
		}

		printk(KERN_DEBUG "pseries_idle_driver registered\n");

		return 0;
		}

		static void __exit pseries_processor_idle_exit(void)
		{

		pseries_idle_devices_uninit();
		cpuidle_unregister_driver(&pseries_idle_driver);

		return;
		}

		module_init(pseries_processor_idle_init);
		module_exit(pseries_processor_idle_exit);

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

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