arch/powerpc/kernel/idle_power4.S

   1 /*
   2  *  This file contains the power_save function for 970-family CPUs.
   3  *
   4  *  This program is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU General Public License
   6  *  as published by the Free Software Foundation; either version
   7  *  2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/config.h>
  11 #include <linux/threads.h>
  12 #include <asm/processor.h>
  13 #include <asm/page.h>
  14 #include <asm/cputable.h>
  15 #include <asm/thread_info.h>
  16 #include <asm/ppc_asm.h>
  17 #include <asm/asm-offsets.h>
  18
  19 #undef DEBUG
  20
  21         .text
  22
  23 _GLOBAL(power4_idle)
  24 BEGIN_FTR_SECTION
  25         blr
  26 END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP)
  27         /* Now check if user or arch enabled NAP mode */
  28         LOAD_REG_ADDRBASE(r3,powersave_nap)
  29         lwz     r4,ADDROFF(powersave_nap)(r3)
  30         cmpwi   0,r4,0
  31         beqlr
  32
  33         /* Go to NAP now */
  34 BEGIN_FTR_SECTION
  35         DSSALL
  36         sync
  37 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
  38         clrrdi  r9,r1,THREAD_SHIFT      /* current thread_info */
  39         ld      r8,TI_LOCAL_FLAGS(r9)   /* set napping bit */
  40         ori     r8,r8,_TLF_NAPPING      /* so when we take an exception */
  41         std     r8,TI_LOCAL_FLAGS(r9)   /* it will return to our caller */
  42         mfmsr   r7
  43         ori     r7,r7,MSR_EE
  44         oris    r7,r7,MSR_POW@h
  45 1:      sync
  46         isync
  47         mtmsrd  r7
  48         isync
  49         b       1b
  50