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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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>.
 */

#include <linux/init.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>

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 = "db8500-cpuidle",
	},
	.probe = dbx500_cpuidle_probe,
};
builtin_platform_driver(dbx500_cpuidle_plat_driver);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
3ebabaa5 DL	2	/*
	3	* Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
	4	*
	5	* Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
	6	* and Jonas Aaberg <jonas.aberg@stericsson.com>.
3ebabaa5 DL	7	*/
3ebabaa5 DL	8
fdc7d515	9	#include <linux/init.h>
3ebabaa5	10	#include <linux/cpuidle.h>
3ebabaa5 DL	11	#include <linux/spinlock.h>
	12	#include <linux/atomic.h>
	13	#include <linux/smp.h>
	14	#include <linux/mfd/dbx500-prcmu.h>
1e22a8c6	15	#include <linux/platform_data/arm-ux500-pm.h>
8025395f	16	#include <linux/platform_device.h>
3ebabaa5 DL	17
3ebabaa5 DL	18	#include <asm/cpuidle.h>
3ebabaa5 DL	19
	20	static atomic_t master = ATOMIC_INIT(0);
	21	static DEFINE_SPINLOCK(master_lock);
3ebabaa5 DL	22
	23	static inline int ux500_enter_idle(struct cpuidle_device *dev,
	24	struct cpuidle_driver *drv, int index)
	25	{
	26	int this_cpu = smp_processor_id();
	27	bool recouple = false;
	28
3ebabaa5 DL	29	if (atomic_inc_return(&master) == num_online_cpus()) {
	30
	31	/* With this lock, we prevent the other cpu to exit and enter
	32	* this function again and become the master */
	33	if (!spin_trylock(&master_lock))
	34	goto wfi;
	35
	36	/* decouple the gic from the A9 cores */
5cc23666 SZ	37	if (prcmu_gic_decouple()) {
5cc23666 SZ	38	spin_unlock(&master_lock);
3ebabaa5	39	goto out;
5cc23666	40	}
3ebabaa5 DL	41
	42	/* If an error occur, we will have to recouple the gic
	43	* manually */
	44	recouple = true;
	45
	46	/* At this state, as the gic is decoupled, if the other
	47	* cpu is in WFI, we have the guarantee it won't be wake
	48	* up, so we can safely go to retention */
	49	if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
	50	goto out;
	51
	52	/* The prcmu will be in charge of watching the interrupts
	53	* and wake up the cpus */
	54	if (prcmu_copy_gic_settings())
	55	goto out;
	56
	57	/* Check in the meantime an interrupt did
	58	* not occur on the gic ... */
	59	if (prcmu_gic_pending_irq())
	60	goto out;
	61
	62	/* ... and the prcmu */
	63	if (prcmu_pending_irq())
	64	goto out;
	65
	66	/* Go to the retention state, the prcmu will wait for the
	67	* cpu to go WFI and this is what happens after exiting this
	68	* 'master' critical section */
	69	if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
	70	goto out;
	71
	72	/* When we switch to retention, the prcmu is in charge
	73	* of recoupling the gic automatically */
	74	recouple = false;
	75
	76	spin_unlock(&master_lock);
	77	}
	78	wfi:
	79	cpu_do_idle();
	80	out:
	81	atomic_dec(&master);
	82
	83	if (recouple) {
	84	prcmu_gic_recouple();
	85	spin_unlock(&master_lock);
	86	}
	87
3ebabaa5 DL	88	return index;
	89	}
	90
	91	static struct cpuidle_driver ux500_idle_driver = {
	92	.name = "ux500_idle",
	93	.owner = THIS_MODULE,
3ebabaa5 DL	94	.states = {
	95	ARM_CPUIDLE_WFI_STATE,
	96	{
	97	.enter = ux500_enter_idle,
	98	.exit_latency = 70,
	99	.target_residency = 260,
b82b6cca	100	.flags = CPUIDLE_FLAG_TIMER_STOP,
3ebabaa5 DL	101	.name = "ApIdle",
	102	.desc = "ARM Retention",
	103	},
	104	},
	105	.safe_state_index = 0,
	106	.state_count = 2,
	107	};
	108
2c2b24d9	109	static int dbx500_cpuidle_probe(struct platform_device *pdev)
3ebabaa5	110	{
1e22a8c6	111	/* Configure wake up reasons */
3ebabaa5 DL	112	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) \| PRCMU_WAKEUP(RTC) \|
	113	PRCMU_WAKEUP(ABB));
	114
e8928e2e	115	return cpuidle_register(&ux500_idle_driver, NULL);
3ebabaa5 DL	116	}
3ebabaa5 DL	117
8025395f LW	118	static struct platform_driver dbx500_cpuidle_plat_driver = {
8025395f LW	119	.driver = {
f28fd3b6	120	.name = "db8500-cpuidle",
8025395f LW	121	},
	122	.probe = dbx500_cpuidle_probe,
	123	};
fdc7d515	124	builtin_platform_driver(dbx500_cpuidle_plat_driver);