linux-stable/drivers/cpuidle/cpuidle-ux500.c
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  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

  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 #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00

124 lines
3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>.
*/
#include <linux/init.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 <linux/platform_device.h>
#include <asm/cpuidle.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_TIMER_STOP,
.name = "ApIdle",
.desc = "ARM Retention",
},
},
.safe_state_index = 0,
.state_count = 2,
};
static int dbx500_cpuidle_probe(struct platform_device *pdev)
{
/* Configure wake up reasons */
prcmu_enable_wakeups(PRCMU_WAKEUP(ARM) | PRCMU_WAKEUP(RTC) |
PRCMU_WAKEUP(ABB));
return cpuidle_register(&ux500_idle_driver, NULL);
}
static struct platform_driver dbx500_cpuidle_plat_driver = {
.driver = {
.name = "cpuidle-dbx500",
},
.probe = dbx500_cpuidle_probe,
};
builtin_platform_driver(dbx500_cpuidle_plat_driver);