linux/drivers/cpuidle/cpuidle-arm64.c
Lorenzo Pieralisi af3cfdbf56 arm64: kernel: remove ARM64_CPU_SUSPEND config option
ARM64_CPU_SUSPEND config option was introduced to make code providing
context save/restore selectable only on platforms requiring power
management capabilities.

Currently ARM64_CPU_SUSPEND depends on the PM_SLEEP config option which
in turn is set by the SUSPEND config option.

The introduction of CPU_IDLE for arm64 requires that code configured
by ARM64_CPU_SUSPEND (context save/restore) should be compiled in
in order to enable the CPU idle driver to rely on CPU operations
carrying out context save/restore.

The ARM64_CPUIDLE config option (ARM64 generic idle driver) is therefore
forced to select ARM64_CPU_SUSPEND, even if there may be (ie PM_SLEEP)
failed dependencies, which is not a clean way of handling the kernel
configuration option.

For these reasons, this patch removes the ARM64_CPU_SUSPEND config option
and makes the context save/restore dependent on CPU_PM, which is selected
whenever either SUSPEND or CPU_IDLE are configured, cleaning up dependencies
in the process.

This way, code previously configured through ARM64_CPU_SUSPEND is
compiled in whenever a power management subsystem requires it to be
present in the kernel (SUSPEND || CPU_IDLE), which is the behaviour
expected on ARM64 kernels.

The cpu_suspend and cpu_init_idle CPU operations are added only if
CPU_IDLE is selected, since they are CPU_IDLE specific methods and
should be grouped and defined accordingly.

PSCI CPU operations are updated to reflect the introduced changes.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-01-27 11:35:33 +00:00

123 lines
3.0 KiB
C

/*
* ARM64 generic CPU idle driver.
*
* Copyright (C) 2014 ARM Ltd.
* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.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.
*/
#define pr_fmt(fmt) "CPUidle arm64: " fmt
#include <linux/cpuidle.h>
#include <linux/cpumask.h>
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <asm/cpuidle.h>
#include "dt_idle_states.h"
/*
* arm64_enter_idle_state - Programs CPU to enter the specified state
*
* dev: cpuidle device
* drv: cpuidle driver
* idx: state index
*
* Called from the CPUidle framework to program the device to the
* specified target state selected by the governor.
*/
static int arm64_enter_idle_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
int ret;
if (!idx) {
cpu_do_idle();
return idx;
}
ret = cpu_pm_enter();
if (!ret) {
/*
* Pass idle state index to cpu_suspend which in turn will
* call the CPU ops suspend protocol with idle index as a
* parameter.
*/
ret = cpu_suspend(idx);
cpu_pm_exit();
}
return ret ? -1 : idx;
}
static struct cpuidle_driver arm64_idle_driver = {
.name = "arm64_idle",
.owner = THIS_MODULE,
/*
* State at index 0 is standby wfi and considered standard
* on all ARM platforms. If in some platforms simple wfi
* can't be used as "state 0", DT bindings must be implemented
* to work around this issue and allow installing a special
* handler for idle state index 0.
*/
.states[0] = {
.enter = arm64_enter_idle_state,
.exit_latency = 1,
.target_residency = 1,
.power_usage = UINT_MAX,
.name = "WFI",
.desc = "ARM64 WFI",
}
};
static const struct of_device_id arm64_idle_state_match[] __initconst = {
{ .compatible = "arm,idle-state",
.data = arm64_enter_idle_state },
{ },
};
/*
* arm64_idle_init
*
* Registers the arm64 specific cpuidle driver with the cpuidle
* framework. It relies on core code to parse the idle states
* and initialize them using driver data structures accordingly.
*/
static int __init arm64_idle_init(void)
{
int cpu, ret;
struct cpuidle_driver *drv = &arm64_idle_driver;
/*
* Initialize idle states data, starting at index 1.
* This driver is DT only, if no DT idle states are detected (ret == 0)
* let the driver initialization fail accordingly since there is no
* reason to initialize the idle driver if only wfi is supported.
*/
ret = dt_init_idle_driver(drv, arm64_idle_state_match, 1);
if (ret <= 0)
return ret ? : -ENODEV;
/*
* Call arch CPU operations in order to initialize
* idle states suspend back-end specific data
*/
for_each_possible_cpu(cpu) {
ret = cpu_init_idle(cpu);
if (ret) {
pr_err("CPU %d failed to init idle CPU ops\n", cpu);
return ret;
}
}
return cpuidle_register(drv, NULL);
}
device_initcall(arm64_idle_init);