idle.c

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/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Maintained by: Olof Johansson <[email protected]>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#undef DEBUG

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/irq.h>

#include <asm/machdep.h>
#include <asm/reg.h>
#include <asm/smp.h>

#include "pasemi.h"

struct sleep_mode {
    char *name;
    void (*entry)(void);
};

static struct sleep_mode modes[] = {
    { .name = "spin", .entry = &idle_spin },
    { .name = "doze", .entry = &idle_doze },
};

static int current_mode = 0;

static int pasemi_system_reset_exception(struct pt_regs *regs)
{
    /* If we were woken up from power savings, we need to return
     * to the calling function, since nip is not saved across
     * all modes.
     */

    if (regs->msr & SRR1_WAKEMASK)
        regs->nip = regs->link;

    switch (regs->msr & SRR1_WAKEMASK) {
    case SRR1_WAKEEE:
        do_IRQ(regs);
        break;
    case SRR1_WAKEDEC:
        timer_interrupt(regs);
        break;
    default:
        /* do system reset */
        return 0;
    }

    /* Set higher astate since we come out of power savings at 0 */
    restore_astate(hard_smp_processor_id());

    /* everything handled */
    regs->msr |= MSR_RI;
    return 1;
}

static int __init pasemi_idle_init(void)
{
#ifndef CONFIG_PPC_PASEMI_CPUFREQ
    printk(KERN_WARNING "No cpufreq driver, powersavings modes disabled\n");
    current_mode = 0;
#endif

    ppc_md.system_reset_exception = pasemi_system_reset_exception;
    ppc_md.power_save = modes[current_mode].entry;
    printk(KERN_INFO "Using PA6T idle loop (%s)\n", modes[current_mode].name);

    return 0;
}
machine_late_initcall(pasemi, pasemi_idle_init);

static int __init idle_param(char *p)
{
    int i;
    for (i = 0; i < ARRAY_SIZE(modes); i++) {
        if (!strcmp(modes[i].name, p)) {
            current_mode = i;
            break;
        }
    }
    return 0;
}

early_param("idle", idle_param);