arch/powerpc/kernel/idle_power7.S

   1 /*
   2  *  This file contains the power_save function for Power7 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/ppc-opcode.h>
  18 #include <asm/hw_irq.h>
  19 #include <asm/kvm_book3s_asm.h>
  20
  21 #undef DEBUG
  22
  23         .text
  24
  25 _GLOBAL(power7_idle)
  26         /* Now check if user or arch enabled NAP mode */
  27         LOAD_REG_ADDRBASE(r3,powersave_nap)
  28         lwz     r4,ADDROFF(powersave_nap)(r3)
  29         cmpwi   0,r4,0
  30         beqlr
  31
  32         /* NAP is a state loss, we create a regs frame on the
  33          * stack, fill it up with the state we care about and
  34          * stick a pointer to it in PACAR1. We really only
  35          * need to save PC, some CR bits and the NV GPRs,
  36          * but for now an interrupt frame will do.
  37          */
  38         mflr    r0
  39         std     r0,16(r1)
  40         stdu    r1,-INT_FRAME_SIZE(r1)
  41         std     r0,_LINK(r1)
  42         std     r0,_NIP(r1)
  43
  44 #ifndef CONFIG_SMP
  45         /* Make sure FPU, VSX etc... are flushed as we may lose
  46          * state when going to nap mode
  47          */
  48         bl      .discard_lazy_cpu_state
  49 #endif /* CONFIG_SMP */
  50
  51         /* Hard disable interrupts */
  52         mfmsr   r9
  53         rldicl  r9,r9,48,1
  54         rotldi  r9,r9,16
  55         mtmsrd  r9,1                    /* hard-disable interrupts */
  56
  57         /* Check if something happened while soft-disabled */
  58         lbz     r0,PACAIRQHAPPENED(r13)
  59         cmpwi   cr0,r0,0
  60         beq     1f
  61         addi    r1,r1,INT_FRAME_SIZE
  62         ld      r0,16(r1)
  63         mtlr    r0
  64         blr
  65
  66 1:      /* We mark irqs hard disabled as this is the state we'll
  67          * be in when returning and we need to tell arch_local_irq_restore()
  68          * about it
  69          */
  70         li      r0,PACA_IRQ_HARD_DIS
  71         stb     r0,PACAIRQHAPPENED(r13)
  72
  73         /* We haven't lost state ... yet */
  74         li      r0,0
  75         stb     r0,PACA_NAPSTATELOST(r13)
  76
  77         /* Continue saving state */
  78         SAVE_GPR(2, r1)
  79         SAVE_NVGPRS(r1)
  80         mfcr    r3
  81         std     r3,_CCR(r1)
  82         std     r9,_MSR(r1)
  83         std     r1,PACAR1(r13)
  84
  85 #ifdef CONFIG_KVM_BOOK3S_64_HV
  86         /* Tell KVM we're napping */
  87         li      r4,KVM_HWTHREAD_IN_NAP
  88         stb     r4,HSTATE_HWTHREAD_STATE(r13)
  89 #endif
  90
  91         /* Magic NAP mode enter sequence */
  92         std     r0,0(r1)
  93         ptesync
  94         ld      r0,0(r1)
  95 1:      cmp     cr0,r0,r0
  96         bne     1b
  97         PPC_NAP
  98         b       .
  99
 100 _GLOBAL(power7_wakeup_loss)
 101         ld      r1,PACAR1(r13)
 102         REST_NVGPRS(r1)
 103         REST_GPR(2, r1)
 104         ld      r3,_CCR(r1)
 105         ld      r4,_MSR(r1)
 106         ld      r5,_NIP(r1)
 107         addi    r1,r1,INT_FRAME_SIZE
 108         mtcr    r3
 109         mtspr   SPRN_SRR1,r4
 110         mtspr   SPRN_SRR0,r5
 111         rfid
 112
 113 _GLOBAL(power7_wakeup_noloss)
 114         lbz     r0,PACA_NAPSTATELOST(r13)
 115         cmpwi   r0,0
 116         bne     .power7_wakeup_loss
 117         ld      r1,PACAR1(r13)
 118         ld      r4,_MSR(r1)
 119         ld      r5,_NIP(r1)
 120         addi    r1,r1,INT_FRAME_SIZE
 121         mtspr   SPRN_SRR1,r4
 122         mtspr   SPRN_SRR0,r5
 123         rfid