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00482a4078
This patch groups the self-refresh on/cpu_do_idle/self-refresh off into a single 'standby' function. The standby routine for rm9200 has been turned into an asm routine to have a better control of the self refresh and to prevent a memory access when running this code. Draining the write buffer is done automatically when switching for the self refresh on sam9, so the instruction is added to the rm9200 only. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
96 lines
2.6 KiB
C
96 lines
2.6 KiB
C
/*
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* based on arch/arm/mach-kirkwood/cpuidle.c
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*
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* CPU idle support for AT91 SoC
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*
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* The cpu idle uses wait-for-interrupt and RAM self refresh in order
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* to implement two idle states -
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* #1 wait-for-interrupt
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* #2 wait-for-interrupt and RAM self refresh
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/cpuidle.h>
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#include <asm/proc-fns.h>
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#include <linux/io.h>
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#include <linux/export.h>
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#include "pm.h"
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#define AT91_MAX_STATES 2
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static DEFINE_PER_CPU(struct cpuidle_device, at91_cpuidle_device);
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static struct cpuidle_driver at91_idle_driver = {
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.name = "at91_idle",
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.owner = THIS_MODULE,
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};
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/* Actual code that puts the SoC in different idle states */
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static int at91_enter_idle(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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struct timeval before, after;
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int idle_time;
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local_irq_disable();
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do_gettimeofday(&before);
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if (index == 0)
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/* Wait for interrupt state */
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cpu_do_idle();
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else if (index == 1)
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at91_standby();
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do_gettimeofday(&after);
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local_irq_enable();
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idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
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(after.tv_usec - before.tv_usec);
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dev->last_residency = idle_time;
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return index;
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}
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/* Initialize CPU idle by registering the idle states */
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static int at91_init_cpuidle(void)
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{
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struct cpuidle_device *device;
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struct cpuidle_driver *driver = &at91_idle_driver;
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device = &per_cpu(at91_cpuidle_device, smp_processor_id());
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device->state_count = AT91_MAX_STATES;
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driver->state_count = AT91_MAX_STATES;
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/* Wait for interrupt state */
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driver->states[0].enter = at91_enter_idle;
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driver->states[0].exit_latency = 1;
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driver->states[0].target_residency = 10000;
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driver->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
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strcpy(driver->states[0].name, "WFI");
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strcpy(driver->states[0].desc, "Wait for interrupt");
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/* Wait for interrupt and RAM self refresh state */
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driver->states[1].enter = at91_enter_idle;
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driver->states[1].exit_latency = 10;
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driver->states[1].target_residency = 10000;
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driver->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
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strcpy(driver->states[1].name, "RAM_SR");
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strcpy(driver->states[1].desc, "WFI and RAM Self Refresh");
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cpuidle_register_driver(&at91_idle_driver);
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if (cpuidle_register_device(device)) {
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printk(KERN_ERR "at91_init_cpuidle: Failed registering\n");
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return -EIO;
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}
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return 0;
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}
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device_initcall(at91_init_cpuidle);
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