[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())
			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 */
	43	if (prcmu_gic_decouple())
	44	goto out;
	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
92	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
93
94	return index;
95	}
96
97	static struct cpuidle_driver ux500_idle_driver = {
98	.name = "ux500_idle",
99	.owner = THIS_MODULE,
100	.en_core_tk_irqen = 1,
101	.states = {
102	ARM_CPUIDLE_WFI_STATE,
103	{
104	.enter = ux500_enter_idle,
105	.exit_latency = 70,
106	.target_residency = 260,
107	.flags = CPUIDLE_FLAG_TIME_VALID,
108	.name = "ApIdle",
109	.desc = "ARM Retention",
110	},
111	},
112	.safe_state_index = 0,
113	.state_count = 2,
114	};
115
116	/*
117	* For each cpu, setup the broadcast timer because we will
118	* need to migrate the timers for the states >= ApIdle.
119	*/
120	static void ux500_setup_broadcast_timer(void *arg)
121	{
122	int cpu = smp_processor_id();
123	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
124	}
125
126	int __init ux500_idle_init(void)
127	{
128	int ret, cpu;
129	struct cpuidle_device *device;
130
131	/* Configure wake up reasons */
132	prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) \| PRCMU_WAKEUP(RTC) \|
133	PRCMU_WAKEUP(ABB));
134
135	/*
136	* Configure the timer broadcast for each cpu, that must
137	* be done from the cpu context, so we use a smp cross
138	* call with 'on_each_cpu'.
139	*/
140	on_each_cpu(ux500_setup_broadcast_timer, NULL, 1);
141
142	ret = cpuidle_register_driver(&ux500_idle_driver);
143	if (ret) {
144	printk(KERN_ERR "failed to register ux500 idle driver\n");
145	return ret;
146	}
147
148	for_each_online_cpu(cpu) {
149	device = &per_cpu(ux500_cpuidle_device, cpu);
150	device->cpu = cpu;
151	ret = cpuidle_register_device(device);
152	if (ret) {
153	printk(KERN_ERR "Failed to register cpuidle "
154	"device for cpu%d\n", cpu);
155	goto out_unregister;
156	}
157	}
158	out:
159	return ret;
160
161	out_unregister:
162	for_each_online_cpu(cpu) {
163	device = &per_cpu(ux500_cpuidle_device, cpu);
164	cpuidle_unregister_device(device);
165	}
166
167	cpuidle_unregister_driver(&ux500_idle_driver);
168	goto out;
169	}
170
171	device_initcall(ux500_idle_init);