[linux-2.6-block.git] / drivers / cpuidle / cpuidle-ux500.c

/*
 * Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
 *
 * Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
 * and Jonas Aaberg <jonas.aberg@stericsson.com>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/cpuidle.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/smp.h>
#include <linux/mfd/dbx500-prcmu.h>
#include <linux/platform_data/arm-ux500-pm.h>
#include <linux/platform_device.h>

#include <asm/cpuidle.h>
#include <asm/proc-fns.h>

static atomic_t master = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(master_lock);

static inline int ux500_enter_idle(struct cpuidle_device *dev,
				   struct cpuidle_driver *drv, int index)
{
	int this_cpu = smp_processor_id();
	bool recouple = false;

	if (atomic_inc_return(&master) == num_online_cpus()) {

		/* With this lock, we prevent the other cpu to exit and enter
		 * this function again and become the master */
		if (!spin_trylock(&master_lock))
			goto wfi;

		/* decouple the gic from the A9 cores */
		if (prcmu_gic_decouple()) {
			spin_unlock(&master_lock);
			goto out;
		}

		/* If an error occur, we will have to recouple the gic
		 * manually */
		recouple = true;

		/* At this state, as the gic is decoupled, if the other
		 * cpu is in WFI, we have the guarantee it won't be wake
		 * up, so we can safely go to retention */
		if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
			goto out;

		/* The prcmu will be in charge of watching the interrupts
		 * and wake up the cpus */
		if (prcmu_copy_gic_settings())
			goto out;

		/* Check in the meantime an interrupt did
		 * not occur on the gic ... */
		if (prcmu_gic_pending_irq())
			goto out;

		/* ... and the prcmu */
		if (prcmu_pending_irq())
			goto out;

		/* Go to the retention state, the prcmu will wait for the
		 * cpu to go WFI and this is what happens after exiting this
		 * 'master' critical section */
		if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
			goto out;

		/* When we switch to retention, the prcmu is in charge
		 * of recoupling the gic automatically */
		recouple = false;

		spin_unlock(&master_lock);
	}
wfi:
	cpu_do_idle();
out:
	atomic_dec(&master);

	if (recouple) {
		prcmu_gic_recouple();
		spin_unlock(&master_lock);
	}

	return index;
}

static struct cpuidle_driver ux500_idle_driver = {
	.name = "ux500_idle",
	.owner = THIS_MODULE,
	.states = {
		ARM_CPUIDLE_WFI_STATE,
		{
			.enter		  = ux500_enter_idle,
			.exit_latency	  = 70,
			.target_residency = 260,
			.flags		  = CPUIDLE_FLAG_TIMER_STOP,
			.name		  = "ApIdle",
			.desc		  = "ARM Retention",
		},
	},
	.safe_state_index = 0,
	.state_count = 2,
};

static int dbx500_cpuidle_probe(struct platform_device *pdev)
{
	/* Configure wake up reasons */
	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
			     PRCMU_WAKEUP(ABB));

	return cpuidle_register(&ux500_idle_driver, NULL);
}

static struct platform_driver dbx500_cpuidle_plat_driver = {
	.driver = {
		.name = "cpuidle-dbx500",
	},
	.probe = dbx500_cpuidle_probe,
};

module_platform_driver(dbx500_cpuidle_plat_driver);
Commit	Line	Data
3ebabaa5 DL	1	/*
	2	* Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
	3	*
	4	* Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
	5	* and Jonas Aaberg <jonas.aberg@stericsson.com>.
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/cpuidle.h>
3ebabaa5 DL	14	#include <linux/spinlock.h>
	15	#include <linux/atomic.h>
	16	#include <linux/smp.h>
	17	#include <linux/mfd/dbx500-prcmu.h>
1e22a8c6	18	#include <linux/platform_data/arm-ux500-pm.h>
8025395f	19	#include <linux/platform_device.h>
3ebabaa5 DL	20
	21	#include <asm/cpuidle.h>
	22	#include <asm/proc-fns.h>
	23
	24	static atomic_t master = ATOMIC_INIT(0);
	25	static DEFINE_SPINLOCK(master_lock);
3ebabaa5 DL	26
	27	static inline int ux500_enter_idle(struct cpuidle_device *dev,
	28	struct cpuidle_driver *drv, int index)
	29	{
	30	int this_cpu = smp_processor_id();
	31	bool recouple = false;
	32
3ebabaa5 DL	33	if (atomic_inc_return(&master) == num_online_cpus()) {
	34
	35	/* With this lock, we prevent the other cpu to exit and enter
	36	* this function again and become the master */
	37	if (!spin_trylock(&master_lock))
	38	goto wfi;
	39
	40	/* decouple the gic from the A9 cores */
5cc23666 SZ	41	if (prcmu_gic_decouple()) {
5cc23666 SZ	42	spin_unlock(&master_lock);
3ebabaa5	43	goto out;
5cc23666	44	}
3ebabaa5 DL	45
	46	/* If an error occur, we will have to recouple the gic
	47	* manually */
	48	recouple = true;
	49
	50	/* At this state, as the gic is decoupled, if the other
	51	* cpu is in WFI, we have the guarantee it won't be wake
	52	* up, so we can safely go to retention */
	53	if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
	54	goto out;
	55
	56	/* The prcmu will be in charge of watching the interrupts
	57	* and wake up the cpus */
	58	if (prcmu_copy_gic_settings())
	59	goto out;
	60
	61	/* Check in the meantime an interrupt did
	62	* not occur on the gic ... */
	63	if (prcmu_gic_pending_irq())
	64	goto out;
	65
	66	/* ... and the prcmu */
	67	if (prcmu_pending_irq())
	68	goto out;
	69
	70	/* Go to the retention state, the prcmu will wait for the
	71	* cpu to go WFI and this is what happens after exiting this
	72	* 'master' critical section */
	73	if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
	74	goto out;
	75
	76	/* When we switch to retention, the prcmu is in charge
	77	* of recoupling the gic automatically */
	78	recouple = false;
	79
	80	spin_unlock(&master_lock);
	81	}
	82	wfi:
	83	cpu_do_idle();
	84	out:
	85	atomic_dec(&master);
	86
	87	if (recouple) {
	88	prcmu_gic_recouple();
	89	spin_unlock(&master_lock);
	90	}
	91
3ebabaa5 DL	92	return index;
	93	}
	94
	95	static struct cpuidle_driver ux500_idle_driver = {
	96	.name = "ux500_idle",
	97	.owner = THIS_MODULE,
3ebabaa5 DL	98	.states = {
	99	ARM_CPUIDLE_WFI_STATE,
	100	{
	101	.enter = ux500_enter_idle,
	102	.exit_latency = 70,
	103	.target_residency = 260,
b82b6cca	104	.flags = CPUIDLE_FLAG_TIMER_STOP,
3ebabaa5 DL	105	.name = "ApIdle",
	106	.desc = "ARM Retention",
	107	},
	108	},
	109	.safe_state_index = 0,
	110	.state_count = 2,
	111	};
	112
2c2b24d9	113	static int dbx500_cpuidle_probe(struct platform_device *pdev)
3ebabaa5	114	{
1e22a8c6	115	/* Configure wake up reasons */
3ebabaa5 DL	116	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) \| PRCMU_WAKEUP(RTC) \|
	117	PRCMU_WAKEUP(ABB));
	118
e8928e2e	119	return cpuidle_register(&ux500_idle_driver, NULL);
3ebabaa5 DL	120	}
3ebabaa5 DL	121
8025395f LW	122	static struct platform_driver dbx500_cpuidle_plat_driver = {
	123	.driver = {
	124	.name = "cpuidle-dbx500",
8025395f LW	125	},
	126	.probe = dbx500_cpuidle_probe,
	127	};
	128
	129	module_platform_driver(dbx500_cpuidle_plat_driver);