linux/drivers/cpuidle/cpuidle-cps.c
Daniel Lezcano b82b6cca48 cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logic
The only place where the time is invalid is when the ACPI_CSTATE_FFH entry
method is not set. Otherwise for all the drivers, the time can be correctly
measured.

Instead of duplicating the CPUIDLE_FLAG_TIME_VALID flag in all the drivers
for all the states, just invert the logic by replacing it by the flag
CPUIDLE_FLAG_TIME_INVALID, hence we can set this flag only for the acpi idle
driver, remove the former flag from all the drivers and invert the logic with
this flag in the different governor.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-11-12 21:17:27 +01:00

184 lines
4.4 KiB
C

/*
* Copyright (C) 2014 Imagination Technologies
* Author: Paul Burton <paul.burton@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/cpu_pm.h>
#include <linux/cpuidle.h>
#include <linux/init.h>
#include <asm/idle.h>
#include <asm/pm-cps.h>
/* Enumeration of the various idle states this driver may enter */
enum cps_idle_state {
STATE_WAIT = 0, /* MIPS wait instruction, coherent */
STATE_NC_WAIT, /* MIPS wait instruction, non-coherent */
STATE_CLOCK_GATED, /* Core clock gated */
STATE_POWER_GATED, /* Core power gated */
STATE_COUNT
};
static int cps_nc_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index)
{
enum cps_pm_state pm_state;
int err;
/*
* At least one core must remain powered up & clocked in order for the
* system to have any hope of functioning.
*
* TODO: don't treat core 0 specially, just prevent the final core
* TODO: remap interrupt affinity temporarily
*/
if (!cpu_data[dev->cpu].core && (index > STATE_NC_WAIT))
index = STATE_NC_WAIT;
/* Select the appropriate cps_pm_state */
switch (index) {
case STATE_NC_WAIT:
pm_state = CPS_PM_NC_WAIT;
break;
case STATE_CLOCK_GATED:
pm_state = CPS_PM_CLOCK_GATED;
break;
case STATE_POWER_GATED:
pm_state = CPS_PM_POWER_GATED;
break;
default:
BUG();
return -EINVAL;
}
/* Notify listeners the CPU is about to power down */
if ((pm_state == CPS_PM_POWER_GATED) && cpu_pm_enter())
return -EINTR;
/* Enter that state */
err = cps_pm_enter_state(pm_state);
/* Notify listeners the CPU is back up */
if (pm_state == CPS_PM_POWER_GATED)
cpu_pm_exit();
return err ?: index;
}
static struct cpuidle_driver cps_driver = {
.name = "cpc_cpuidle",
.owner = THIS_MODULE,
.states = {
[STATE_WAIT] = MIPS_CPUIDLE_WAIT_STATE,
[STATE_NC_WAIT] = {
.enter = cps_nc_enter,
.exit_latency = 200,
.target_residency = 450,
.name = "nc-wait",
.desc = "non-coherent MIPS wait",
},
[STATE_CLOCK_GATED] = {
.enter = cps_nc_enter,
.exit_latency = 300,
.target_residency = 700,
.flags = CPUIDLE_FLAG_TIMER_STOP,
.name = "clock-gated",
.desc = "core clock gated",
},
[STATE_POWER_GATED] = {
.enter = cps_nc_enter,
.exit_latency = 600,
.target_residency = 1000,
.flags = CPUIDLE_FLAG_TIMER_STOP,
.name = "power-gated",
.desc = "core power gated",
},
},
.state_count = STATE_COUNT,
.safe_state_index = 0,
};
static void __init cps_cpuidle_unregister(void)
{
int cpu;
struct cpuidle_device *device;
for_each_possible_cpu(cpu) {
device = &per_cpu(cpuidle_dev, cpu);
cpuidle_unregister_device(device);
}
cpuidle_unregister_driver(&cps_driver);
}
static int __init cps_cpuidle_init(void)
{
int err, cpu, core, i;
struct cpuidle_device *device;
/* Detect supported states */
if (!cps_pm_support_state(CPS_PM_POWER_GATED))
cps_driver.state_count = STATE_CLOCK_GATED + 1;
if (!cps_pm_support_state(CPS_PM_CLOCK_GATED))
cps_driver.state_count = STATE_NC_WAIT + 1;
if (!cps_pm_support_state(CPS_PM_NC_WAIT))
cps_driver.state_count = STATE_WAIT + 1;
/* Inform the user if some states are unavailable */
if (cps_driver.state_count < STATE_COUNT) {
pr_info("cpuidle-cps: limited to ");
switch (cps_driver.state_count - 1) {
case STATE_WAIT:
pr_cont("coherent wait\n");
break;
case STATE_NC_WAIT:
pr_cont("non-coherent wait\n");
break;
case STATE_CLOCK_GATED:
pr_cont("clock gating\n");
break;
}
}
/*
* Set the coupled flag on the appropriate states if this system
* requires it.
*/
if (coupled_coherence)
for (i = STATE_NC_WAIT; i < cps_driver.state_count; i++)
cps_driver.states[i].flags |= CPUIDLE_FLAG_COUPLED;
err = cpuidle_register_driver(&cps_driver);
if (err) {
pr_err("Failed to register CPS cpuidle driver\n");
return err;
}
for_each_possible_cpu(cpu) {
core = cpu_data[cpu].core;
device = &per_cpu(cpuidle_dev, cpu);
device->cpu = cpu;
#ifdef CONFIG_MIPS_MT
cpumask_copy(&device->coupled_cpus, &cpu_sibling_map[cpu]);
#endif
err = cpuidle_register_device(device);
if (err) {
pr_err("Failed to register CPU%d cpuidle device\n",
cpu);
goto err_out;
}
}
return 0;
err_out:
cps_cpuidle_unregister();
return err;
}
device_initcall(cps_cpuidle_init);