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Daniel Lezcano3ebabaa2012-04-19 14:46:32 +02001/*
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>
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020014#include <linux/spinlock.h>
15#include <linux/atomic.h>
16#include <linux/smp.h>
17#include <linux/mfd/dbx500-prcmu.h>
Linus Walleij1e22a8c2013-03-19 15:36:12 +010018#include <linux/platform_data/arm-ux500-pm.h>
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020019
20#include <asm/cpuidle.h>
21#include <asm/proc-fns.h>
22
Linus Walleij174e7792013-03-19 15:41:55 +010023#include "db8500-regs.h"
24
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020025static atomic_t master = ATOMIC_INIT(0);
26static DEFINE_SPINLOCK(master_lock);
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020027
28static inline int ux500_enter_idle(struct cpuidle_device *dev,
29 struct cpuidle_driver *drv, int index)
30{
31 int this_cpu = smp_processor_id();
32 bool recouple = false;
33
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020034 if (atomic_inc_return(&master) == num_online_cpus()) {
35
36 /* With this lock, we prevent the other cpu to exit and enter
37 * this function again and become the master */
38 if (!spin_trylock(&master_lock))
39 goto wfi;
40
41 /* decouple the gic from the A9 cores */
Steve Zhan5cc23662013-01-23 11:24:47 +010042 if (prcmu_gic_decouple()) {
43 spin_unlock(&master_lock);
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020044 goto out;
Steve Zhan5cc23662013-01-23 11:24:47 +010045 }
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020046
47 /* If an error occur, we will have to recouple the gic
48 * manually */
49 recouple = true;
50
51 /* At this state, as the gic is decoupled, if the other
52 * cpu is in WFI, we have the guarantee it won't be wake
53 * up, so we can safely go to retention */
54 if (!prcmu_is_cpu_in_wfi(this_cpu ? 0 : 1))
55 goto out;
56
57 /* The prcmu will be in charge of watching the interrupts
58 * and wake up the cpus */
59 if (prcmu_copy_gic_settings())
60 goto out;
61
62 /* Check in the meantime an interrupt did
63 * not occur on the gic ... */
64 if (prcmu_gic_pending_irq())
65 goto out;
66
67 /* ... and the prcmu */
68 if (prcmu_pending_irq())
69 goto out;
70
71 /* Go to the retention state, the prcmu will wait for the
72 * cpu to go WFI and this is what happens after exiting this
73 * 'master' critical section */
74 if (prcmu_set_power_state(PRCMU_AP_IDLE, true, true))
75 goto out;
76
77 /* When we switch to retention, the prcmu is in charge
78 * of recoupling the gic automatically */
79 recouple = false;
80
81 spin_unlock(&master_lock);
82 }
83wfi:
84 cpu_do_idle();
85out:
86 atomic_dec(&master);
87
88 if (recouple) {
89 prcmu_gic_recouple();
90 spin_unlock(&master_lock);
91 }
92
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020093 return index;
94}
95
96static struct cpuidle_driver ux500_idle_driver = {
97 .name = "ux500_idle",
98 .owner = THIS_MODULE,
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020099 .states = {
100 ARM_CPUIDLE_WFI_STATE,
101 {
102 .enter = ux500_enter_idle,
103 .exit_latency = 70,
104 .target_residency = 260,
Daniel Lezcanod2b578e2013-03-21 12:21:34 +0000105 .flags = CPUIDLE_FLAG_TIME_VALID |
106 CPUIDLE_FLAG_TIMER_STOP,
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200107 .name = "ApIdle",
108 .desc = "ARM Retention",
109 },
110 },
111 .safe_state_index = 0,
112 .state_count = 2,
113};
114
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200115int __init ux500_idle_init(void)
116{
Linus Walleij1e22a8c2013-03-19 15:36:12 +0100117 /* Configure wake up reasons */
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200118 prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
119 PRCMU_WAKEUP(ABB));
120
Daniel Lezcanoe8928e22013-04-23 08:54:34 +0000121 return cpuidle_register(&ux500_idle_driver, NULL);
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200122}
123
124device_initcall(ux500_idle_init);