LXR linux/arch/powerpc/kernel/idle

   1/*
   2 * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved.
   3 * Dave Liu <daveliu@freescale.com>
   4 * copy from idle_6xx.S and modify for e500 based processor,
   5 * implement the power_save function in idle.
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the License, or (at your option) any later version.
  11 */
  12
  13#include <linux/threads.h>
  14#include <asm/reg.h>
  15#include <asm/page.h>
  16#include <asm/cputable.h>
  17#include <asm/thread_info.h>
  18#include <asm/ppc_asm.h>
  19#include <asm/asm-offsets.h>
  20
  21        .text
  22
  23_GLOBAL(e500_idle)
  24        CURRENT_THREAD_INFO(r3, r1)
  25        lwz     r4,TI_LOCAL_FLAGS(r3)   /* set napping bit */
  26        ori     r4,r4,_TLF_NAPPING      /* so when we take an exception */
  27        stw     r4,TI_LOCAL_FLAGS(r3)   /* it will return to our caller */
  28
  29#ifdef CONFIG_PPC_E500MC
  30        wrteei  1
  311:      wait
  32
  33        /*
  34         * Guard against spurious wakeups (e.g. from a hypervisor) --
  35         * any real interrupt will cause us to return to LR due to
  36         * _TLF_NAPPING.
  37         */
  38        b       1b
  39#else
  40        /* Check if we can nap or doze, put HID0 mask in r3 */
  41        lis     r3,0
  42BEGIN_FTR_SECTION
  43        lis     r3,HID0_DOZE@h
  44END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
  45
  46BEGIN_FTR_SECTION
  47        /* Now check if user enabled NAP mode */
  48        lis     r4,powersave_nap@ha
  49        lwz     r4,powersave_nap@l(r4)
  50        cmpwi   0,r4,0
  51        beq     1f
  52        stwu    r1,-16(r1)
  53        mflr    r0
  54        stw     r0,20(r1)
  55        bl      flush_dcache_L1
  56        lwz     r0,20(r1)
  57        addi    r1,r1,16
  58        mtlr    r0
  59        lis     r3,HID0_NAP@h
  60END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
  611:
  62        /* Go to NAP or DOZE now */
  63        mfspr   r4,SPRN_HID0
  64        rlwinm  r4,r4,0,~(HID0_DOZE|HID0_NAP|HID0_SLEEP)
  65        or      r4,r4,r3
  66        isync
  67        mtspr   SPRN_HID0,r4
  68        isync
  69
  70        mfmsr   r7
  71        oris    r7,r7,MSR_WE@h
  72        ori     r7,r7,MSR_EE
  73        msync
  74        mtmsr   r7
  75        isync
  762:      b       2b
  77#endif /* !E500MC */
  78
  79/*
  80 * Return from NAP/DOZE mode, restore some CPU specific registers,
  81 * r2 containing physical address of current.
  82 * r11 points to the exception frame (physical address).
  83 * We have to preserve r10.
  84 */
  85_GLOBAL(power_save_ppc32_restore)
  86        lwz     r9,_LINK(r11)           /* interrupted in e500_idle */
  87        stw     r9,_NIP(r11)            /* make it do a blr */
  88
  89#ifdef CONFIG_SMP
  90        CURRENT_THREAD_INFO(r12, r1)
  91        lwz     r11,TI_CPU(r12)         /* get cpu number * 4 */
  92        slwi    r11,r11,2
  93#else
  94        li      r11,0
  95#endif
  96
  97        b       transfer_to_handler_cont
  98