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
  26 #include <asm/machdep.h>
  27 #include <asm/reg.h>
  28
  29 #include "pasemi.h"
  30
  31 struct sleep_mode {
  32         char *name;
  33         void (*entry)(void);
  34 };
  35
  36 static struct sleep_mode modes[] = {
  37         { .name = "spin", .entry = &idle_spin },
  38         { .name = "doze", .entry = &idle_doze },
  39 };
  40
  41 static int current_mode = 0;
  42
  43 static int pasemi_system_reset_exception(struct pt_regs *regs)
  44 {
  45         /* If we were woken up from power savings, we need to return
  46          * to the calling function, since nip is not saved across
  47          * all modes.
  48          */
  49
  50         if (regs->msr & SRR1_WAKEMASK)
  51                 regs->nip = regs->link;
  52
  53         switch (regs->msr & SRR1_WAKEMASK) {
  54         case SRR1_WAKEEE:
  55                 do_IRQ(regs);
  56                 break;
  57         case SRR1_WAKEDEC:
  58                 timer_interrupt(regs);
  59                 break;
  60         default:
  61                 /* do system reset */
  62                 return 0;
  63         }
  64         /* everything handled */
  65         regs->msr |= MSR_RI;
  66         return 1;
  67 }
  68
  69 void __init pasemi_idle_init(void)
  70 {
  71         ppc_md.system_reset_exception = pasemi_system_reset_exception;
  72         ppc_md.power_save = modes[current_mode].entry;
  73         printk(KERN_INFO "Using PA6T idle loop (%s)\n", modes[current_mode].name);
  74 }
  75
  76 static int __init idle_param(char *p)
  77 {
  78         int i;
  79         for (i = 0; i < sizeof(modes)/sizeof(struct sleep_mode); i++) {
  80                 if (!strcmp(modes[i].name, p)) {
  81                         current_mode = i;
  82                         break;
  83                 }
  84         }
  85         return 0;
  86 }
  87
  88 early_param("idle", idle_param);