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 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 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 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_PAGEMASK, 2 /* SegCtl0 */
76 LONG_S k0, SSS_SEGCTL0(t1)
77 mfc0 k0, CP0_PAGEMASK, 3 /* SegCtl1 */
78 LONG_S k0, SSS_SEGCTL1(t1)
79 mfc0 k0, CP0_PAGEMASK, 4 /* 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_PAGEMASK, 2 /* SegCtl0 */
96 LONG_L k0, SSS_SEGCTL1(t1)
97 mtc0 k0, CP0_PAGEMASK, 3 /* SegCtl1 */
98 LONG_L k0, SSS_SEGCTL2(t1)
99 mtc0 k0, CP0_PAGEMASK, 4 /* 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 __wback_cache_all
109 .set push
110 .set noreorder
111 la t1, __wback_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 */