blob: 5e35804b1a952393dd84b20aacaf96442eac4d62 [file] [log] [blame]
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>
Linus Walleij80253952013-07-10 15:35:26 +020019#include <linux/platform_device.h>
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020020
21#include <asm/cpuidle.h>
22#include <asm/proc-fns.h>
23
24static atomic_t master = ATOMIC_INIT(0);
25static DEFINE_SPINLOCK(master_lock);
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020026
27static 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
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020033 if (atomic_inc_return(&master) == num_online_cpus()) {
34
35 /* With this lock, we prevent the other cpu to exit and enter
36 * this function again and become the master */
37 if (!spin_trylock(&master_lock))
38 goto wfi;
39
40 /* decouple the gic from the A9 cores */
Steve Zhan5cc23662013-01-23 11:24:47 +010041 if (prcmu_gic_decouple()) {
42 spin_unlock(&master_lock);
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020043 goto out;
Steve Zhan5cc23662013-01-23 11:24:47 +010044 }
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020045
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 }
82wfi:
83 cpu_do_idle();
84out:
85 atomic_dec(&master);
86
87 if (recouple) {
88 prcmu_gic_recouple();
89 spin_unlock(&master_lock);
90 }
91
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020092 return index;
93}
94
95static struct cpuidle_driver ux500_idle_driver = {
96 .name = "ux500_idle",
97 .owner = THIS_MODULE,
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +020098 .states = {
99 ARM_CPUIDLE_WFI_STATE,
100 {
101 .enter = ux500_enter_idle,
102 .exit_latency = 70,
103 .target_residency = 260,
Daniel Lezcanod2b578e2013-03-21 12:21:34 +0000104 .flags = CPUIDLE_FLAG_TIME_VALID |
105 CPUIDLE_FLAG_TIMER_STOP,
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200106 .name = "ApIdle",
107 .desc = "ARM Retention",
108 },
109 },
110 .safe_state_index = 0,
111 .state_count = 2,
112};
113
Daniel Lezcano2c2b24d2013-09-27 18:57:07 +0200114static int dbx500_cpuidle_probe(struct platform_device *pdev)
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200115{
Linus Walleij1e22a8c2013-03-19 15:36:12 +0100116 /* Configure wake up reasons */
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200117 prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
118 PRCMU_WAKEUP(ABB));
119
Daniel Lezcanoe8928e22013-04-23 08:54:34 +0000120 return cpuidle_register(&ux500_idle_driver, NULL);
Daniel Lezcano3ebabaa2012-04-19 14:46:32 +0200121}
122
Linus Walleij80253952013-07-10 15:35:26 +0200123static struct platform_driver dbx500_cpuidle_plat_driver = {
124 .driver = {
125 .name = "cpuidle-dbx500",
126 .owner = THIS_MODULE,
127 },
128 .probe = dbx500_cpuidle_probe,
129};
130
131module_platform_driver(dbx500_cpuidle_plat_driver);