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Commit dd3ad97c authored by Santosh Shilimkar's avatar Santosh Shilimkar Committed by Kevin Hilman
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ARM: OMAP4: CPUidle: Use coupled cpuidle states to implement SMP cpuidle. 



OMAP4 CPUDILE driver is converted mainly based on notes from the
coupled cpuidle patch series.

The changes include :
- Register both CPUs and C-states to cpuidle driver.
- Set struct cpuidle_device.coupled_cpus
- Set struct cpuidle_device.safe_state to non coupled state.
- Set CPUIDLE_FLAG_COUPLED in struct cpuidle_state.flags for each
  state that affects multiple cpus.
- Separate ->enter hooks for coupled & simple idle.
- CPU0 wait loop for CPU1 power transition.
- CPU1 wakeup mechanism for the idle exit.
- Enabling ARCH_NEEDS_CPU_IDLE_COUPLED for OMAP4.

Thanks to Kevin Hilman and Colin Cross on the suggestions/fixes
on the intermediate version of this patch.

Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: default avatarKevin Hilman <khilman@ti.com>
parent 11d6ec2e

arch/arm/mach-omap2/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ config ARCH_OMAP4 
	select PM_OPP if PM

	select USB_ARCH_HAS_EHCI if USB_SUPPORT

	select ARM_CPU_SUSPEND if PM

	select ARCH_NEEDS_CPU_IDLE_COUPLED



comment "OMAP Core Type"

	depends on ARCH_OMAP2

arch/arm/mach-omap2/cpuidle44xx.c

+66 −46
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include "common.h"

#include "pm.h"

#include "prm.h"

#include "clockdomain.h"



#ifdef CONFIG_CPU_IDLE
@@ -49,10 +50,11 @@ static struct omap4_idle_statedata omap4_idle_data[] = { 
	},

};



static struct powerdomain *mpu_pd, *cpu0_pd, *cpu1_pd;

static struct powerdomain *mpu_pd, *cpu_pd[NR_CPUS];

static struct clockdomain *cpu_clkdm[NR_CPUS];



/**

 * omap4_enter_idle - Programs OMAP4 to enter the specified state

 * omap4_enter_idle_coupled_[simple/coupled] - OMAP4 cpuidle entry functions

 * @dev: cpuidle device

 * @drv: cpuidle driver

 * @index: the index of state to be entered
@@ -61,40 +63,46 @@ static struct powerdomain *mpu_pd, *cpu0_pd, *cpu1_pd; 
 * specified low power state selected by the governor.

 * Returns the amount of time spent in the low power state.

 */

static int omap4_enter_idle(struct cpuidle_device *dev,

static int omap4_enter_idle_simple(struct cpuidle_device *dev,

			struct cpuidle_driver *drv,

			int index)

{

	local_fiq_disable();

	omap_do_wfi();

	local_fiq_enable();



	return index;

}



static int omap4_enter_idle_coupled(struct cpuidle_device *dev,

			struct cpuidle_driver *drv,

			int index)

{

	struct omap4_idle_statedata *cx = &omap4_idle_data[index];

	u32 cpu1_state;

	int cpu_id = smp_processor_id();



	local_fiq_disable();



	/*

	 * CPU0 has to stay ON (i.e in C1) until CPU1 is OFF state.

	 * CPU0 has to wait and stay ON until CPU1 is OFF state.

	 * This is necessary to honour hardware recommondation

	 * of triggeing all the possible low power modes once CPU1 is

	 * out of coherency and in OFF mode.

	 * Update dev->last_state so that governor stats reflects right

	 * data.

	 */

	cpu1_state = pwrdm_read_pwrst(cpu1_pd);

	if (cpu1_state != PWRDM_POWER_OFF) {

		index = drv->safe_state_index;

		cx = &omap4_idle_data[index];

	if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {

		while (pwrdm_read_pwrst(cpu_pd[1]) != PWRDM_POWER_OFF)

			cpu_relax();

	}



	if (index > 0)

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);



	/*

	 * Call idle CPU PM enter notifier chain so that

	 * VFP and per CPU interrupt context is saved.

	 */

	if (cx->cpu_state == PWRDM_POWER_OFF)

	cpu_pm_enter();



	if (dev->cpu == 0) {

		pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);

		omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
@@ -105,15 +113,20 @@ static int omap4_enter_idle(struct cpuidle_device *dev, 
		if ((cx->mpu_state == PWRDM_POWER_RET) &&

			(cx->mpu_logic_state == PWRDM_POWER_OFF))

				cpu_cluster_pm_enter();

	}



	omap4_enter_lowpower(dev->cpu, cx->cpu_state);



	/* Wakeup CPU1 only if it is not offlined */

	if (dev->cpu == 0 && cpumask_test_cpu(1, cpu_online_mask)) {

		clkdm_wakeup(cpu_clkdm[1]);

		clkdm_allow_idle(cpu_clkdm[1]);

	}



	/*

	 * Call idle CPU PM exit notifier chain to restore

	 * VFP and per CPU IRQ context. Only CPU0 state is

	 * considered since CPU1 is managed by CPU hotplug.

	 * VFP and per CPU IRQ context.

	 */

	if (pwrdm_read_prev_pwrst(cpu0_pd) == PWRDM_POWER_OFF)

	cpu_pm_exit();



	/*
@@ -123,7 +136,6 @@ static int omap4_enter_idle(struct cpuidle_device *dev, 
	if (omap4_mpuss_read_prev_context_state())

		cpu_cluster_pm_exit();



	if (index > 0)

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);



	local_fiq_enable();
@@ -143,7 +155,7 @@ struct cpuidle_driver omap4_idle_driver = { 
			.exit_latency = 2 + 2,

			.target_residency = 5,

			.flags = CPUIDLE_FLAG_TIME_VALID,

			.enter = omap4_enter_idle,

			.enter = omap4_enter_idle_simple,

			.name = "C1",

			.desc = "MPUSS ON"

		},
@@ -151,8 +163,8 @@ struct cpuidle_driver omap4_idle_driver = { 
                        /* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */

			.exit_latency = 328 + 440,

			.target_residency = 960,

			.flags = CPUIDLE_FLAG_TIME_VALID,

			.enter = omap4_enter_idle,

			.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED,

			.enter = omap4_enter_idle_coupled,

			.name = "C2",

			.desc = "MPUSS CSWR",

		},
@@ -160,8 +172,8 @@ struct cpuidle_driver omap4_idle_driver = { 
			/* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */

			.exit_latency = 460 + 518,

			.target_residency = 1100,

			.flags = CPUIDLE_FLAG_TIME_VALID,

			.enter = omap4_enter_idle,

			.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED,

			.enter = omap4_enter_idle_coupled,

			.name = "C3",

			.desc = "MPUSS OSWR",

		},
@@ -182,20 +194,28 @@ int __init omap4_idle_init(void) 
	unsigned int cpu_id = 0;



	mpu_pd = pwrdm_lookup("mpu_pwrdm");

	cpu0_pd = pwrdm_lookup("cpu0_pwrdm");

	cpu1_pd = pwrdm_lookup("cpu1_pwrdm");

	if ((!mpu_pd) || (!cpu0_pd) || (!cpu1_pd))

	cpu_pd[0] = pwrdm_lookup("cpu0_pwrdm");

	cpu_pd[1] = pwrdm_lookup("cpu1_pwrdm");

	if ((!mpu_pd) || (!cpu_pd[0]) || (!cpu_pd[1]))

		return -ENODEV;



	cpu_clkdm[0] = clkdm_lookup("mpu0_clkdm");

	cpu_clkdm[1] = clkdm_lookup("mpu1_clkdm");

	if (!cpu_clkdm[0] || !cpu_clkdm[1])

		return -ENODEV;



	for_each_cpu(cpu_id, cpu_online_mask) {

		dev = &per_cpu(omap4_idle_dev, cpu_id);

		dev->cpu = cpu_id;

		dev->coupled_cpus = *cpu_online_mask;



		cpuidle_register_driver(&omap4_idle_driver);



		if (cpuidle_register_device(dev)) {

		pr_err("%s: CPUidle register device failed\n", __func__);

			pr_err("%s: CPUidle register failed\n", __func__);

			return -EIO;

		}

	}



	return 0;

}