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/spinlock.h>
15 #include <linux/atomic.h>
16 #include <linux/smp.h>
17 #include <linux/mfd/dbx500-prcmu.h>
18 #include <linux/platform_data/arm-ux500-pm.h>
20 #include <asm/cpuidle.h>
21 #include <asm/proc-fns.h>
23 #include "db8500-regs.h"
26 static atomic_t master
= ATOMIC_INIT(0);
27 static DEFINE_SPINLOCK(master_lock
);
29 static inline int ux500_enter_idle(struct cpuidle_device
*dev
,
30 struct cpuidle_driver
*drv
, int index
)
32 int this_cpu
= smp_processor_id();
33 bool recouple
= false;
35 if (atomic_inc_return(&master
) == num_online_cpus()) {
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
))
42 /* decouple the gic from the A9 cores */
43 if (prcmu_gic_decouple()) {
44 spin_unlock(&master_lock
);
48 /* If an error occur, we will have to recouple the gic
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))
58 /* The prcmu will be in charge of watching the interrupts
59 * and wake up the cpus */
60 if (prcmu_copy_gic_settings())
63 /* Check in the meantime an interrupt did
64 * not occur on the gic ... */
65 if (prcmu_gic_pending_irq())
68 /* ... and the prcmu */
69 if (prcmu_pending_irq())
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))
78 /* When we switch to retention, the prcmu is in charge
79 * of recoupling the gic automatically */
82 spin_unlock(&master_lock
);
91 spin_unlock(&master_lock
);
97 static struct cpuidle_driver ux500_idle_driver
= {
101 ARM_CPUIDLE_WFI_STATE
,
103 .enter
= ux500_enter_idle
,
105 .target_residency
= 260,
106 .flags
= CPUIDLE_FLAG_TIME_VALID
|
107 CPUIDLE_FLAG_TIMER_STOP
,
109 .desc
= "ARM Retention",
112 .safe_state_index
= 0,
116 int __init
ux500_idle_init(void)
118 if (!(cpu_is_u8500_family() || cpu_is_ux540_family()))
121 /* Configure wake up reasons */
122 prcmu_enable_wakeups(PRCMU_WAKEUP(ARM
) | PRCMU_WAKEUP(RTC
) |
125 return cpuidle_register(&ux500_idle_driver
, NULL
);
128 device_initcall(ux500_idle_init
);