arch/powerpc/platforms/44x/idle.c

   1 /*
   2  * Copyright 2008 IBM Corp.
   3  *
   4  * Based on arch/powerpc/platforms/pasemi/idle.c:
   5  * Copyright (C) 2006-2007 PA Semi, Inc
   6  *
   7  * Added by: Jerone Young <jyoung5@us.ibm.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  21  *
  22  */
  23
  24 #include <linux/of.h>
  25 #include <linux/kernel.h>
  26 #include <asm/machdep.h>
  27
  28 static int mode_spin;
  29
  30 static void ppc44x_idle(void)
  31 {
  32         unsigned long msr_save;
  33
  34         msr_save = mfmsr();
  35         /* set wait state MSR */
  36         mtmsr(msr_save|MSR_WE|MSR_EE|MSR_CE|MSR_DE);
  37         isync();
  38         /* return to initial state */
  39         mtmsr(msr_save);
  40         isync();
  41 }
  42
  43 int __init ppc44x_idle_init(void)
  44 {
  45         if (!mode_spin) {
  46                 /* If we are not setting spin mode
  47                    then we set to wait mode */
  48                 ppc_md.power_save = &ppc44x_idle;
  49         }
  50
  51         return 0;
  52 }
  53
  54 arch_initcall(ppc44x_idle_init);
  55
  56 static int __init idle_param(char *p)
  57 {
  58
  59         if (!strcmp("spin", p)) {
  60                 mode_spin = 1;
  61                 ppc_md.power_save = NULL;
  62         }
  63
  64         return 0;
  65 }
  66
  67 early_param("idle", idle_param);