kernel/2.6.29.6-aldebaran-rt/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
  33 struct sleep_mode {
  34         char *name;
  35         void (*entry)(void);
  36 };
  37
  38 static struct sleep_mode modes[] = {
  39         { .name = "spin", .entry = &idle_spin },
  40         { .name = "doze", .entry = &idle_doze },
  41 };
  42
  43 static int current_mode = 0;
  44
  45 static 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
  75 static 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 }
  88 machine_late_initcall(pasemi, pasemi_idle_init);
  89
  90 static int __init idle_param(char *p)
  91 {
  92         int i;
  93         for (i = 0; i < sizeof(modes)/sizeof(struct sleep_mode); i++) {
  94                 if (!strcmp(modes[i].name, p)) {
  95                         current_mode = i;
  96                         break;
  97                 }
  98         }
  99         return 0;
 100 }
 101
 102 early_param("idle", idle_param);