cpuidle.c

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/*
 * arch/sh/kernel/cpu/shmobile/cpuidle.c
 *
 * Cpuidle support code for SuperH Mobile
 *
 *  Copyright (C) 2009 Magnus Damm
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/suspend.h>
#include <linux/cpuidle.h>
#include <linux/export.h>
#include <asm/suspend.h>
#include <asm/uaccess.h>

static unsigned long cpuidle_mode[] = {
    SUSP_SH_SLEEP, /* regular sleep mode */
    SUSP_SH_SLEEP | SUSP_SH_SF, /* sleep mode + self refresh */
    SUSP_SH_STANDBY | SUSP_SH_SF, /* software standby mode + self refresh */
};

static int cpuidle_sleep_enter(struct cpuidle_device *dev,
                struct cpuidle_driver *drv,
                int index)
{
    unsigned long allowed_mode = SUSP_SH_SLEEP;
    int requested_state = index;
    int allowed_state;
    int k;

    /* convert allowed mode to allowed state */
    for (k = ARRAY_SIZE(cpuidle_mode) - 1; k > 0; k--)
        if (cpuidle_mode[k] == allowed_mode)
            break;

    allowed_state = k;

    /* take the following into account for sleep mode selection:
     * - allowed_state: best mode allowed by hardware (clock deps)
     * - requested_state: best mode allowed by software (latencies)
     */
    k = min_t(int, allowed_state, requested_state);

    sh_mobile_call_standby(cpuidle_mode[k]);

    return k;
}

static struct cpuidle_device cpuidle_dev;
static struct cpuidle_driver cpuidle_driver = {
    .name           = "sh_idle",
    .owner          = THIS_MODULE,
    .en_core_tk_irqen   = 1,
};

void sh_mobile_setup_cpuidle(void)
{
    struct cpuidle_device *dev = &cpuidle_dev;
    struct cpuidle_driver *drv = &cpuidle_driver;
    struct cpuidle_state *state;
    int i;


    for (i = 0; i < CPUIDLE_STATE_MAX; i++) {
        drv->states[i].name[0] = '\0';
        drv->states[i].desc[0] = '\0';
    }

    i = CPUIDLE_DRIVER_STATE_START;

    state = &drv->states[i++];
    snprintf(state->name, CPUIDLE_NAME_LEN, "C1");
    strncpy(state->desc, "SuperH Sleep Mode", CPUIDLE_DESC_LEN);
    state->exit_latency = 1;
    state->target_residency = 1 * 2;
    state->power_usage = 3;
    state->flags = 0;
    state->flags |= CPUIDLE_FLAG_TIME_VALID;
    state->enter = cpuidle_sleep_enter;

    drv->safe_state_index = i-1;

    if (sh_mobile_sleep_supported & SUSP_SH_SF) {
        state = &drv->states[i++];
        snprintf(state->name, CPUIDLE_NAME_LEN, "C2");
        strncpy(state->desc, "SuperH Sleep Mode [SF]",
            CPUIDLE_DESC_LEN);
        state->exit_latency = 100;
        state->target_residency = 1 * 2;
        state->power_usage = 1;
        state->flags = 0;
        state->flags |= CPUIDLE_FLAG_TIME_VALID;
        state->enter = cpuidle_sleep_enter;
    }

    if (sh_mobile_sleep_supported & SUSP_SH_STANDBY) {
        state = &drv->states[i++];
        snprintf(state->name, CPUIDLE_NAME_LEN, "C3");
        strncpy(state->desc, "SuperH Mobile Standby Mode [SF]",
            CPUIDLE_DESC_LEN);
        state->exit_latency = 2300;
        state->target_residency = 1 * 2;
        state->power_usage = 1;
        state->flags = 0;
        state->flags |= CPUIDLE_FLAG_TIME_VALID;
        state->enter = cpuidle_sleep_enter;
    }

    drv->state_count = i;
    dev->state_count = i;

    cpuidle_register_driver(&cpuidle_driver);

    cpuidle_register_device(dev);
}