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/threads.h>
  11 #include <asm/processor.h>
  12 #include <asm/page.h>
  13 #include <asm/cputable.h>
  14 #include <asm/thread_info.h>
  15 #include <asm/ppc_asm.h>
  16 #include <asm/asm-offsets.h>
  17 #include <asm/irqflags.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         /* Hard disable interrupts */
  34         mfmsr   r7
  35         rldicl  r0,r7,48,1
  36         rotldi  r0,r0,16
  37         mtmsrd  r0,1
  38
  39         /* Check if something happened while soft-disabled */
  40         lbz     r0,PACAIRQHAPPENED(r13)
  41         cmpwi   cr0,r0,0
  42         bnelr
  43
  44         /* Soft-enable interrupts */
  45 #ifdef CONFIG_TRACE_IRQFLAGS
  46         mflr    r0
  47         std     r0,16(r1)
  48         stdu    r1,-128(r1)
  49         bl      .trace_hardirqs_on
  50         addi    r1,r1,128
  51         ld      r0,16(r1)
  52         mtlr    r0
  53         mfmsr   r7
  54 #endif /* CONFIG_TRACE_IRQFLAGS */
  55
  56         li      r0,1
  57         stb     r0,PACASOFTIRQEN(r13)   /* we'll hard-enable shortly */
  58 BEGIN_FTR_SECTION
  59         DSSALL
  60         sync
  61 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
  62         CURRENT_THREAD_INFO(r9, r1)
  63         ld      r8,TI_LOCAL_FLAGS(r9)   /* set napping bit */
  64         ori     r8,r8,_TLF_NAPPING      /* so when we take an exception */
  65         std     r8,TI_LOCAL_FLAGS(r9)   /* it will return to our caller */
  66         ori     r7,r7,MSR_EE
  67         oris    r7,r7,MSR_POW@h
  68 1:      sync
  69         isync
  70         mtmsrd  r7
  71         isync
  72         b       1b
  73