mirror of
https://github.com/torvalds/linux.git
synced 2024-11-19 02:21:47 +00:00
2c06897e45
Multiplatform calls all enabled platforms' initcalls. In the ux500_idle_init() initcall we call into the DBx500-PRCMU which in turn executes some ux500 specific register reads/writes. When running on some !ux500 platforms this ends up causing a kernel Oops. This patch ensures the PRCMU call is only invoked when running on ux500 based platforms. Reported-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
129 lines
3.1 KiB
C
129 lines
3.1 KiB
C
/*
|
|
* Copyright (c) 2012 Linaro : Daniel Lezcano <daniel.lezcano@linaro.org> (IBM)
|
|
*
|
|
* Based on the work of Rickard Andersson <rickard.andersson@stericsson.com>
|
|
* and Jonas Aaberg <jonas.aberg@stericsson.com>.
|
|
*
|
|
* 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/spinlock.h>
|
|
#include <linux/atomic.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/mfd/dbx500-prcmu.h>
|
|
#include <linux/platform_data/arm-ux500-pm.h>
|
|
|
|
#include <asm/cpuidle.h>
|
|
#include <asm/proc-fns.h>
|
|
|
|
#include "db8500-regs.h"
|
|
#include "id.h"
|
|
|
|
static atomic_t master = ATOMIC_INIT(0);
|
|
static DEFINE_SPINLOCK(master_lock);
|
|
|
|
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;
|
|
|
|
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()) {
|
|
spin_unlock(&master_lock);
|
|
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);
|
|
}
|
|
|
|
return index;
|
|
}
|
|
|
|
static struct cpuidle_driver ux500_idle_driver = {
|
|
.name = "ux500_idle",
|
|
.owner = THIS_MODULE,
|
|
.states = {
|
|
ARM_CPUIDLE_WFI_STATE,
|
|
{
|
|
.enter = ux500_enter_idle,
|
|
.exit_latency = 70,
|
|
.target_residency = 260,
|
|
.flags = CPUIDLE_FLAG_TIME_VALID |
|
|
CPUIDLE_FLAG_TIMER_STOP,
|
|
.name = "ApIdle",
|
|
.desc = "ARM Retention",
|
|
},
|
|
},
|
|
.safe_state_index = 0,
|
|
.state_count = 2,
|
|
};
|
|
|
|
int __init ux500_idle_init(void)
|
|
{
|
|
if (!(cpu_is_u8500_family() || cpu_is_ux540_family()))
|
|
return -ENODEV;
|
|
|
|
/* Configure wake up reasons */
|
|
prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
|
|
PRCMU_WAKEUP(ABB));
|
|
|
|
return cpuidle_register(&ux500_idle_driver, NULL);
|
|
}
|
|
|
|
device_initcall(ux500_idle_init);
|