[linux.git] / arch / arm / mach-ux500 / cpuidle.c

/*
 * Copyright (c) 2012 Linaro : Daniel Lezcano <[email protected]> (IBM)
 *
 * Based on the work of Rickard Andersson <[email protected]>
 * and Jonas Aaberg <[email protected]>.
 *
 * 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/clockchips.h>
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/smp.h>
#include <linux/mfd/dbx500-prcmu.h>

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

static atomic_t master = ATOMIC_INIT(0);
static DEFINE_SPINLOCK(master_lock);
static DEFINE_PER_CPU(struct cpuidle_device, ux500_cpuidle_device);

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;

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);

	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);
	}

	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);

	return index;
}

static struct cpuidle_driver ux500_idle_driver = {
	.name = "ux500_idle",
	.owner = THIS_MODULE,
	.en_core_tk_irqen = 1,
	.states = {
		ARM_CPUIDLE_WFI_STATE,
		{
			.enter		  = ux500_enter_idle,
			.exit_latency	  = 70,
			.target_residency = 260,
			.flags		  = CPUIDLE_FLAG_TIME_VALID,
			.name		  = "ApIdle",
			.desc		  = "ARM Retention",
		},
	},
	.safe_state_index = 0,
	.state_count = 2,
};

/*
 * For each cpu, setup the broadcast timer because we will
 * need to migrate the timers for the states >= ApIdle.
 */
static void ux500_setup_broadcast_timer(void *arg)
{
	int cpu = smp_processor_id();
	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
}

int __init ux500_idle_init(void)
{
	int ret, cpu;
	struct cpuidle_device *device;

        /* Configure wake up reasons */
	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
			     PRCMU_WAKEUP(ABB));

	/*
	 * Configure the timer broadcast for each cpu, that must
	 * be done from the cpu context, so we use a smp cross
	 * call with 'on_each_cpu'.
	 */
	on_each_cpu(ux500_setup_broadcast_timer, NULL, 1);

	ret = cpuidle_register_driver(&ux500_idle_driver);
	if (ret) {
		printk(KERN_ERR "failed to register ux500 idle driver\n");
		return ret;
	}

	for_each_online_cpu(cpu) {
		device = &per_cpu(ux500_cpuidle_device, cpu);
		device->cpu = cpu;
		ret = cpuidle_register_device(device);
		if (ret) {
			printk(KERN_ERR "Failed to register cpuidle "
			       "device for cpu%d\n", cpu);
			goto out_unregister;
		}
	}
out:
	return ret;

out_unregister:
	for_each_online_cpu(cpu) {
		device = &per_cpu(ux500_cpuidle_device, cpu);
		cpuidle_unregister_device(device);
	}

	cpuidle_unregister_driver(&ux500_idle_driver);
	goto out;
}

device_initcall(ux500_idle_init);
Commit	Line	Data
3ebabaa5 DL	1	/*
	2	* Copyright (c) 2012 Linaro : Daniel Lezcano <[email protected]> (IBM)
	3	*
	4	* Based on the work of Rickard Andersson <[email protected]>
	5	* and Jonas Aaberg <[email protected]>.
	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>
	14	#include <linux/clockchips.h>
	15	#include <linux/spinlock.h>
	16	#include <linux/atomic.h>
	17	#include <linux/smp.h>
	18	#include <linux/mfd/dbx500-prcmu.h>
	19
	20	#include <asm/cpuidle.h>
	21	#include <asm/proc-fns.h>
	22
	23	static atomic_t master = ATOMIC_INIT(0);
	24	static DEFINE_SPINLOCK(master_lock);
	25	static DEFINE_PER_CPU(struct cpuidle_device, ux500_cpuidle_device);
	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
	33	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
	34
	35	if (atomic_inc_return(&master) == num_online_cpus()) {
	36
	37	/* With this lock, we prevent the other cpu to exit and enter
	38	* this function again and become the master */
	39	if (!spin_trylock(&master_lock))
	40	goto wfi;
	41
	42	/* decouple the gic from the A9 cores */
5cc23666 SZ	43	if (prcmu_gic_decouple()) {
5cc23666 SZ	44	spin_unlock(&master_lock);
3ebabaa5	45	goto out;
5cc23666	46	}
3ebabaa5 DL	47
	48	/* If an error occur, we will have to recouple the gic
	49	* manually */
	50	recouple = true;
	51
	52	/* At this state, as the gic is decoupled, if the other
	53	* cpu is in WFI, we have the guarantee it won't be wake
	54	* up, so we can safely go to retention */
	55	if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
	56	goto out;
	57
	58	/* The prcmu will be in charge of watching the interrupts
	59	* and wake up the cpus */
	60	if (prcmu_copy_gic_settings())
	61	goto out;
	62
	63	/* Check in the meantime an interrupt did
	64	* not occur on the gic ... */
	65	if (prcmu_gic_pending_irq())
	66	goto out;
	67
	68	/* ... and the prcmu */
	69	if (prcmu_pending_irq())
	70	goto out;
	71
	72	/* Go to the retention state, the prcmu will wait for the
	73	* cpu to go WFI and this is what happens after exiting this
	74	* 'master' critical section */
	75	if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
	76	goto out;
	77
	78	/* When we switch to retention, the prcmu is in charge
	79	* of recoupling the gic automatically */
	80	recouple = false;
	81
	82	spin_unlock(&master_lock);
	83	}
	84	wfi:
	85	cpu_do_idle();
	86	out:
	87	atomic_dec(&master);
	88
	89	if (recouple) {
	90	prcmu_gic_recouple();
	91	spin_unlock(&master_lock);
	92	}
	93
	94	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
	95
	96	return index;
	97	}
	98
	99	static struct cpuidle_driver ux500_idle_driver = {
	100	.name = "ux500_idle",
	101	.owner = THIS_MODULE,
	102	.en_core_tk_irqen = 1,
	103	.states = {
	104	ARM_CPUIDLE_WFI_STATE,
	105	{
	106	.enter = ux500_enter_idle,
	107	.exit_latency = 70,
	108	.target_residency = 260,
	109	.flags = CPUIDLE_FLAG_TIME_VALID,
	110	.name = "ApIdle",
111	.desc = "ARM Retention",
112	},
113	},
114	.safe_state_index = 0,
115	.state_count = 2,
116	};
117
118	/*
119	* For each cpu, setup the broadcast timer because we will
120	* need to migrate the timers for the states >= ApIdle.
121	*/
122	static void ux500_setup_broadcast_timer(void *arg)
123	{
124	int cpu = smp_processor_id();
125	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
126	}
127
128	int __init ux500_idle_init(void)
129	{
130	int ret, cpu;
131	struct cpuidle_device *device;
132
133	/* Configure wake up reasons */
134	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) \| PRCMU_WAKEUP(RTC) \|
135	PRCMU_WAKEUP(ABB));
136
137	/*
138	* Configure the timer broadcast for each cpu, that must
139	* be done from the cpu context, so we use a smp cross
140	* call with 'on_each_cpu'.
141	*/
142	on_each_cpu(ux500_setup_broadcast_timer, NULL, 1);
143
144	ret = cpuidle_register_driver(&ux500_idle_driver);
145	if (ret) {
146	printk(KERN_ERR "failed to register ux500 idle driver\n");
147	return ret;
148	}
149
150	for_each_online_cpu(cpu) {
151	device = &per_cpu(ux500_cpuidle_device, cpu);
152	device->cpu = cpu;
153	ret = cpuidle_register_device(device);
154	if (ret) {
155	printk(KERN_ERR "Failed to register cpuidle "
156	"device for cpu%d\n", cpu);
157	goto out_unregister;
158	}
159	}
160	out:
161	return ret;
162
163	out_unregister:
164	for_each_online_cpu(cpu) {
165	device = &per_cpu(ux500_cpuidle_device, cpu);
166	cpuidle_unregister_device(device);
167	}
168
169	cpuidle_unregister_driver(&ux500_idle_driver);
170	goto out;
171	}
172
173	device_initcall(ux500_idle_init);