arch/mips/include/asm/pm.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * Copyright (C) 2014 Imagination Technologies Ltd
   4  *
   5  * PM helper macros for CPU power off (e.g. Suspend-to-RAM).
   6  */
   7
   8 #ifndef __ASM_PM_H
   9 #define __ASM_PM_H
  10
  11 #ifdef __ASSEMBLY__
  12
  13 #include <asm/asm-offsets.h>
  14 #include <asm/asm.h>
  15 #include <asm/mipsregs.h>
  16 #include <asm/regdef.h>
  17
  18 /* Save CPU state to stack for suspend to RAM */
  19 .macro SUSPEND_SAVE_REGS
  20         PTR_SUBU        sp, PT_SIZE
  21         /* Call preserved GPRs */
  22         LONG_S  $16, PT_R16(sp)
  23         LONG_S  $17, PT_R17(sp)
  24         LONG_S  $18, PT_R18(sp)
  25         LONG_S  $19, PT_R19(sp)
  26         LONG_S  $20, PT_R20(sp)
  27         LONG_S  $21, PT_R21(sp)
  28         LONG_S  $22, PT_R22(sp)
  29         LONG_S  $23, PT_R23(sp)
  30         LONG_S  $28, PT_R28(sp)
  31         LONG_S  $30, PT_R30(sp)
  32         LONG_S  $31, PT_R31(sp)
  33         /* A couple of CP0 registers with space in pt_regs */
  34         mfc0    k0, CP0_STATUS
  35         LONG_S  k0, PT_STATUS(sp)
  36 .endm
  37
  38 /* Restore CPU state from stack after resume from RAM */
  39 .macro RESUME_RESTORE_REGS_RETURN
  40         .set    push
  41         .set    noreorder
  42         /* A couple of CP0 registers with space in pt_regs */
  43         LONG_L  k0, PT_STATUS(sp)
  44         mtc0    k0, CP0_STATUS
  45         /* Call preserved GPRs */
  46         LONG_L  $16, PT_R16(sp)
  47         LONG_L  $17, PT_R17(sp)
  48         LONG_L  $18, PT_R18(sp)
  49         LONG_L  $19, PT_R19(sp)
  50         LONG_L  $20, PT_R20(sp)
  51         LONG_L  $21, PT_R21(sp)
  52         LONG_L  $22, PT_R22(sp)
  53         LONG_L  $23, PT_R23(sp)
  54         LONG_L  $28, PT_R28(sp)
  55         LONG_L  $30, PT_R30(sp)
  56         LONG_L  $31, PT_R31(sp)
  57         /* Pop and return */
  58         jr      ra
  59          PTR_ADDIU      sp, PT_SIZE
  60         .set    pop
  61 .endm
  62
  63 /* Get address of static suspend state into t1 */
  64 .macro LA_STATIC_SUSPEND
  65         PTR_LA  t1, mips_static_suspend_state
  66 .endm
  67
  68 /* Save important CPU state for early restoration to global data */
  69 .macro SUSPEND_SAVE_STATIC
  70 #ifdef CONFIG_EVA
  71         /*
  72          * Segment configuration is saved in global data where it can be easily
  73          * reloaded without depending on the segment configuration.
  74          */
  75         mfc0    k0, CP0_SEGCTL0
  76         LONG_S  k0, SSS_SEGCTL0(t1)
  77         mfc0    k0, CP0_SEGCTL1
  78         LONG_S  k0, SSS_SEGCTL1(t1)
  79         mfc0    k0, CP0_SEGCTL2
  80         LONG_S  k0, SSS_SEGCTL2(t1)
  81 #endif
  82         /* save stack pointer (pointing to GPRs) */
  83         LONG_S  sp, SSS_SP(t1)
  84 .endm
  85
  86 /* Restore important CPU state early from global data */
  87 .macro RESUME_RESTORE_STATIC
  88 #ifdef CONFIG_EVA
  89         /*
  90          * Segment configuration must be restored prior to any access to
  91          * allocated memory, as it may reside outside of the legacy kernel
  92          * segments.
  93          */
  94         LONG_L  k0, SSS_SEGCTL0(t1)
  95         mtc0    k0, CP0_SEGCTL0
  96         LONG_L  k0, SSS_SEGCTL1(t1)
  97         mtc0    k0, CP0_SEGCTL1
  98         LONG_L  k0, SSS_SEGCTL2(t1)
  99         mtc0    k0, CP0_SEGCTL2
 100         tlbw_use_hazard
 101 #endif
 102         /* restore stack pointer (pointing to GPRs) */
 103         LONG_L  sp, SSS_SP(t1)
 104 .endm
 105
 106 /* flush caches to make sure context has reached memory */
 107 .macro SUSPEND_CACHE_FLUSH
 108         .extern __flush_cache_all
 109         .set    push
 110         .set    noreorder
 111         PTR_LA  t1, __flush_cache_all
 112         LONG_L  t0, 0(t1)
 113         jalr    t0
 114          nop
 115         .set    pop
 116  .endm
 117
 118 /* Save suspend state and flush data caches to RAM */
 119 .macro SUSPEND_SAVE
 120         SUSPEND_SAVE_REGS
 121         LA_STATIC_SUSPEND
 122         SUSPEND_SAVE_STATIC
 123         SUSPEND_CACHE_FLUSH
 124 .endm
 125
 126 /* Restore saved state after resume from RAM and return */
 127 .macro RESUME_RESTORE_RETURN
 128         LA_STATIC_SUSPEND
 129         RESUME_RESTORE_STATIC
 130         RESUME_RESTORE_REGS_RETURN
 131 .endm
 132
 133 #else /* __ASSEMBLY__ */
 134
 135 /**
 136  * struct mips_static_suspend_state - Core saved CPU state across S2R.
 137  * @segctl:     CP0 Segment control registers.
 138  * @sp:         Stack frame where GP register context is saved.
 139  *
 140  * This structure contains minimal CPU state that must be saved in static kernel
 141  * data in order to be able to restore the rest of the state. This includes
 142  * segmentation configuration in the case of EVA being enabled, as they must be
 143  * restored prior to any kmalloc'd memory being referenced (even the stack
 144  * pointer).
 145  */
 146 struct mips_static_suspend_state {
 147 #ifdef CONFIG_EVA
 148         unsigned long segctl[3];
 149 #endif
 150         unsigned long sp;
 151 };
 152
 153 #endif /* !__ASSEMBLY__ */
 154
 155 #endif /* __ASM_PM_HELPERS_H */