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Commit 2c2e6ecf authored by Deepthi Dharwar's avatar Deepthi Dharwar Committed by Benjamin Herrenschmidt
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powerpc/powernv/cpuidle: Back-end cpuidle driver for powernv platform. 



Following patch ports the cpuidle framework for powernv
platform and also implements a cpuidle back-end powernv
idle driver calling on to power7_nap and snooze idle states.

Signed-off-by: default avatarDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 3fa8cad8

arch/powerpc/platforms/powernv/setup.c

+12 −1
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/of_fdt.h>

#include <linux/interrupt.h>

#include <linux/bug.h>

#include <linux/cpuidle.h>



#include <asm/machdep.h>

#include <asm/firmware.h>
@@ -216,6 +217,16 @@ static int __init pnv_probe(void) 
	return 1;

}



void powernv_idle(void)

{

	/* Hook to cpuidle framework if available, else

	 * call on default platform idle code

	 */

	if (cpuidle_idle_call()) {

		power7_idle();

	}

}



define_machine(powernv) {

	.name			= "PowerNV",

	.probe			= pnv_probe,
@@ -225,7 +236,7 @@ define_machine(powernv) { 
	.show_cpuinfo		= pnv_show_cpuinfo,

	.progress		= pnv_progress,

	.machine_shutdown	= pnv_shutdown,

	.power_save             = power7_idle,

	.power_save             = powernv_idle,

	.calibrate_decr		= generic_calibrate_decr,

#ifdef CONFIG_KEXEC

	.kexec_cpu_down		= pnv_kexec_cpu_down,

drivers/cpuidle/Kconfig.powerpc

+9 −0
Original line number Diff line number Diff line
@@ -9,3 +9,12 @@ config PSERIES_CPUIDLE 
	help

	  Select this option to enable processor idle state management

	  through cpuidle subsystem.



config POWERNV_CPUIDLE

	bool "Cpuidle driver for powernv platforms"

	depends on CPU_IDLE

	depends on PPC_POWERNV

	default y

	help

	  Select this option to enable processor idle state management

	  through cpuidle subsystem.

drivers/cpuidle/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -17,3 +17,4 @@ obj-$(CONFIG_ARM_AT91_CPUIDLE) += cpuidle-at91.o 
###############################################################################

# POWERPC drivers

obj-$(CONFIG_PSERIES_CPUIDLE)		+= cpuidle-pseries.o

obj-$(CONFIG_POWERNV_CPUIDLE)		+= cpuidle-powernv.o

drivers/cpuidle/cpuidle-powernv.c

0 → 100644
+169 −0
Original line number Diff line number Diff line 
/*

 *  cpuidle-powernv - idle state cpuidle driver.

 *  Adapted from drivers/cpuidle/cpuidle-pseries

 *

 */



#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/machdep.h>

#include <asm/firmware.h>



struct cpuidle_driver powernv_idle_driver = {

	.name             = "powernv_idle",

	.owner            = THIS_MODULE,

};



static int max_idle_state;

static struct cpuidle_state *cpuidle_state_table;



static int snooze_loop(struct cpuidle_device *dev,

			struct cpuidle_driver *drv,

			int index)

{

	local_irq_enable();

	set_thread_flag(TIF_POLLING_NRFLAG);



	while (!need_resched()) {

		HMT_low();

		HMT_very_low();

	}



	HMT_medium();

	clear_thread_flag(TIF_POLLING_NRFLAG);

	smp_mb();

	return index;

}



static int nap_loop(struct cpuidle_device *dev,

			struct cpuidle_driver *drv,

			int index)

{

	power7_idle();

	return index;

}



/*

 * States for dedicated partition case.

 */

static struct cpuidle_state powernv_states[] = {

	{ /* Snooze */

		.name = "snooze",

		.desc = "snooze",

		.flags = CPUIDLE_FLAG_TIME_VALID,

		.exit_latency = 0,

		.target_residency = 0,

		.enter = &snooze_loop },

	{ /* NAP */

		.name = "NAP",

		.desc = "NAP",

		.flags = CPUIDLE_FLAG_TIME_VALID,

		.exit_latency = 10,

		.target_residency = 100,

		.enter = &nap_loop },

};



static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,

			unsigned long action, void *hcpu)

{

	int hotcpu = (unsigned long)hcpu;

	struct cpuidle_device *dev =

				per_cpu(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 = powernv_cpuidle_add_cpu_notifier,

};



/*

 * powernv_cpuidle_driver_init()

 */

static int powernv_cpuidle_driver_init(void)

{

	int idle_state;

	struct cpuidle_driver *drv = &powernv_idle_driver;



	drv->state_count = 0;



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

		/* 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;

}



/*

 * powernv_idle_probe()

 * Choose state table for shared versus dedicated partition

 */

static int powernv_idle_probe(void)

{



	if (cpuidle_disable != IDLE_NO_OVERRIDE)

		return -ENODEV;



	if (firmware_has_feature(FW_FEATURE_OPALv3)) {

		cpuidle_state_table = powernv_states;

		max_idle_state = ARRAY_SIZE(powernv_states);

 	} else

 		return -ENODEV;



	return 0;

}



static int __init powernv_processor_idle_init(void)

{

	int retval;



	retval = powernv_idle_probe();

	if (retval)

		return retval;



	powernv_cpuidle_driver_init();

	retval = cpuidle_register(&powernv_idle_driver, NULL);

	if (retval) {

		printk(KERN_DEBUG "Registration of powernv driver failed.\n");

		return retval;

	}



	register_cpu_notifier(&setup_hotplug_notifier);

	printk(KERN_DEBUG "powernv_idle_driver registered\n");

	return 0;

}



device_initcall(powernv_processor_idle_init);