2 * Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
4 * Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
5 * and Jonas Aaberg <jonas.aberg@stericsson.com>.
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.
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 #include <linux/platform_data/arm-ux500-pm.h>
21 #include <asm/cpuidle.h>
22 #include <asm/proc-fns.h>
24 #include "db8500-regs.h"
26 static atomic_t master = ATOMIC_INIT(0);
27 static DEFINE_SPINLOCK(master_lock);
28 static DEFINE_PER_CPU(struct cpuidle_device, ux500_cpuidle_device);
30 static inline int ux500_enter_idle(struct cpuidle_device *dev,
31 struct cpuidle_driver *drv, int index)
33 int this_cpu = smp_processor_id();
34 bool recouple = false;
36 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
38 if (atomic_inc_return(&master) == num_online_cpus()) {
40 /* With this lock, we prevent the other cpu to exit and enter
41 * this function again and become the master */
42 if (!spin_trylock(&master_lock))
45 /* decouple the gic from the A9 cores */
46 if (prcmu_gic_decouple()) {
47 spin_unlock(&master_lock);
51 /* If an error occur, we will have to recouple the gic
55 /* At this state, as the gic is decoupled, if the other
56 * cpu is in WFI, we have the guarantee it won't be wake
57 * up, so we can safely go to retention */
58 if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
61 /* The prcmu will be in charge of watching the interrupts
62 * and wake up the cpus */
63 if (prcmu_copy_gic_settings())
66 /* Check in the meantime an interrupt did
67 * not occur on the gic ... */
68 if (prcmu_gic_pending_irq())
71 /* ... and the prcmu */
72 if (prcmu_pending_irq())
75 /* Go to the retention state, the prcmu will wait for the
76 * cpu to go WFI and this is what happens after exiting this
77 * 'master' critical section */
78 if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
81 /* When we switch to retention, the prcmu is in charge
82 * of recoupling the gic automatically */
85 spin_unlock(&master_lock);
94 spin_unlock(&master_lock);
97 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
102 static struct cpuidle_driver ux500_idle_driver = {
103 .name = "ux500_idle",
104 .owner = THIS_MODULE,
105 .en_core_tk_irqen = 1,
107 ARM_CPUIDLE_WFI_STATE,
109 .enter = ux500_enter_idle,
111 .target_residency = 260,
112 .flags = CPUIDLE_FLAG_TIME_VALID,
114 .desc = "ARM Retention",
117 .safe_state_index = 0,
122 * For each cpu, setup the broadcast timer because we will
123 * need to migrate the timers for the states >= ApIdle.
125 static void ux500_setup_broadcast_timer(void *arg)
127 int cpu = smp_processor_id();
128 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
131 int __init ux500_idle_init(void)
134 struct cpuidle_device *device;
136 /* Configure wake up reasons */
137 prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
141 * Configure the timer broadcast for each cpu, that must
142 * be done from the cpu context, so we use a smp cross
143 * call with 'on_each_cpu'.
145 on_each_cpu(ux500_setup_broadcast_timer, NULL, 1);
147 ret = cpuidle_register_driver(&ux500_idle_driver);
149 printk(KERN_ERR "failed to register ux500 idle driver\n");
153 for_each_online_cpu(cpu) {
154 device = &per_cpu(ux500_cpuidle_device, cpu);
156 ret = cpuidle_register_device(device);
158 printk(KERN_ERR "Failed to register cpuidle "
159 "device for cpu%d\n", cpu);
167 for_each_online_cpu(cpu) {
168 device = &per_cpu(ux500_cpuidle_device, cpu);
169 cpuidle_unregister_device(device);
172 cpuidle_unregister_driver(&ux500_idle_driver);
176 device_initcall(ux500_idle_init);