linux-kernel-test/arch/arm/mach-at91/cpuidle.c
Daniel Lezcano a008dad702 ARM: at91: cpuidle: Fix target_residency
The following commit:

commit 7e348b9012
Author: Robert Lee <rob.lee@linaro.org>
Date:   Tue Mar 20 15:22:43 2012 -0500

    ARM: at91: Consolidate time keeping and irq enable

    Enable core cpuidle timekeeping and irq enabling and remove that
    handling from this code.

introduced an additional zero to the state1 (suspend) target residency.

With a periodic tick, the cpu never enters the state1 with both 10000 and
100000.

With a tickless system, it enters to state1 much more often with the
initial value, roughly x7 more.

Fix it by setting the value to 10ms again.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[nicola.ferre@atmel.com: add precisions given by Daniel to commit message]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
2013-06-21 16:52:00 +02:00

69 lines
1.6 KiB
C

/*
* based on arch/arm/mach-kirkwood/cpuidle.c
*
* CPU idle support for AT91 SoC
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* The cpu idle uses wait-for-interrupt and RAM self refresh in order
* to implement two idle states -
* #1 wait-for-interrupt
* #2 wait-for-interrupt and RAM self refresh
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/cpuidle.h>
#include <linux/io.h>
#include <linux/export.h>
#include <asm/proc-fns.h>
#include <asm/cpuidle.h>
#include <mach/cpu.h>
#include "pm.h"
#define AT91_MAX_STATES 2
/* Actual code that puts the SoC in different idle states */
static int at91_enter_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
if (cpu_is_at91rm9200())
at91rm9200_standby();
else if (cpu_is_at91sam9g45())
at91sam9g45_standby();
else if (cpu_is_at91sam9263())
at91sam9263_standby();
else
at91sam9_standby();
return index;
}
static struct cpuidle_driver at91_idle_driver = {
.name = "at91_idle",
.owner = THIS_MODULE,
.states[0] = ARM_CPUIDLE_WFI_STATE,
.states[1] = {
.enter = at91_enter_idle,
.exit_latency = 10,
.target_residency = 10000,
.flags = CPUIDLE_FLAG_TIME_VALID,
.name = "RAM_SR",
.desc = "WFI and DDR Self Refresh",
},
.state_count = AT91_MAX_STATES,
};
/* Initialize CPU idle by registering the idle states */
static int __init at91_init_cpuidle(void)
{
return cpuidle_register(&at91_idle_driver, NULL);
}
device_initcall(at91_init_cpuidle);