LXR linux/arch/powerpc/platforms/pasemi/idle.c

   1/*
   2 * Copyright (C) 2006-2007 PA Semi, Inc
   3 *
   4 * Maintained by: Olof Johansson <olof@lixom.net>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18 *
  19 */
  20
  21#undef DEBUG
  22
  23#include <linux/kernel.h>
  24#include <linux/string.h>
  25#include <linux/irq.h>
  26
  27#include <asm/machdep.h>
  28#include <asm/reg.h>
  29#include <asm/smp.h>
  30
  31#include "pasemi.h"
  32
  33struct sleep_mode {
  34        char *name;
  35        void (*entry)(void);
  36};
  37
  38static struct sleep_mode modes[] = {
  39        { .name = "spin", .entry = &idle_spin },
  40        { .name = "doze", .entry = &idle_doze },
  41};
  42
  43static int current_mode = 0;
  44
  45static int pasemi_system_reset_exception(struct pt_regs *regs)
  46{
  47        /* If we were woken up from power savings, we need to return
  48         * to the calling function, since nip is not saved across
  49         * all modes.
  50         */
  51
  52        if (regs->msr & SRR1_WAKEMASK)
  53                regs->nip = regs->link;
  54
  55        switch (regs->msr & SRR1_WAKEMASK) {
  56        case SRR1_WAKEEE:
  57                do_IRQ(regs);
  58                break;
  59        case SRR1_WAKEDEC:
  60                timer_interrupt(regs);
  61                break;
  62        default:
  63                /* do system reset */
  64                return 0;
  65        }
  66
  67        /* Set higher astate since we come out of power savings at 0 */
  68        restore_astate(hard_smp_processor_id());
  69
  70        /* everything handled */
  71        regs->msr |= MSR_RI;
  72        return 1;
  73}
  74
  75static int __init pasemi_idle_init(void)
  76{
  77#ifndef CONFIG_PPC_PASEMI_CPUFREQ
  78        printk(KERN_WARNING "No cpufreq driver, powersavings modes disabled\n");
  79        current_mode = 0;
  80#endif
  81
  82        ppc_md.system_reset_exception = pasemi_system_reset_exception;
  83        ppc_md.power_save = modes[current_mode].entry;
  84        printk(KERN_INFO "Using PA6T idle loop (%s)\n", modes[current_mode].name);
  85
  86        return 0;
  87}
  88machine_late_initcall(pasemi, pasemi_idle_init);
  89
  90static int __init idle_param(char *p)
  91{
  92        int i;
  93        for (i = 0; i < ARRAY_SIZE(modes); i++) {
  94                if (!strcmp(modes[i].name, p)) {
  95                        current_mode = i;
  96                        break;
  97                }
  98        }
  99        return 0;
 100}
 101
 102early_param("idle", idle_param);
 103