xref: /linux/arch/riscv/kernel/suspend_entry.S (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (c) 2021 Western Digital Corporation or its affiliates.
4 * Copyright (c) 2022 Ventana Micro Systems Inc.
5 */
6
7#include <linux/linkage.h>
8#include <linux/cfi_types.h>
9#include <asm/asm.h>
10#include <asm/asm-offsets.h>
11#include <asm/assembler.h>
12#include <asm/csr.h>
13#include <asm/xip_fixup.h>
14
15	.text
16	.altmacro
17	.option norelax
18
19SYM_FUNC_START(__cpu_suspend_enter)
20	/* Save registers (except A0 and T0-T6) */
21	REG_S	ra, (SUSPEND_CONTEXT_REGS + PT_RA)(a0)
22	REG_S	sp, (SUSPEND_CONTEXT_REGS + PT_SP)(a0)
23	REG_S	gp, (SUSPEND_CONTEXT_REGS + PT_GP)(a0)
24	REG_S	tp, (SUSPEND_CONTEXT_REGS + PT_TP)(a0)
25	REG_S	s0, (SUSPEND_CONTEXT_REGS + PT_S0)(a0)
26	REG_S	s1, (SUSPEND_CONTEXT_REGS + PT_S1)(a0)
27	REG_S	a1, (SUSPEND_CONTEXT_REGS + PT_A1)(a0)
28	REG_S	a2, (SUSPEND_CONTEXT_REGS + PT_A2)(a0)
29	REG_S	a3, (SUSPEND_CONTEXT_REGS + PT_A3)(a0)
30	REG_S	a4, (SUSPEND_CONTEXT_REGS + PT_A4)(a0)
31	REG_S	a5, (SUSPEND_CONTEXT_REGS + PT_A5)(a0)
32	REG_S	a6, (SUSPEND_CONTEXT_REGS + PT_A6)(a0)
33	REG_S	a7, (SUSPEND_CONTEXT_REGS + PT_A7)(a0)
34	REG_S	s2, (SUSPEND_CONTEXT_REGS + PT_S2)(a0)
35	REG_S	s3, (SUSPEND_CONTEXT_REGS + PT_S3)(a0)
36	REG_S	s4, (SUSPEND_CONTEXT_REGS + PT_S4)(a0)
37	REG_S	s5, (SUSPEND_CONTEXT_REGS + PT_S5)(a0)
38	REG_S	s6, (SUSPEND_CONTEXT_REGS + PT_S6)(a0)
39	REG_S	s7, (SUSPEND_CONTEXT_REGS + PT_S7)(a0)
40	REG_S	s8, (SUSPEND_CONTEXT_REGS + PT_S8)(a0)
41	REG_S	s9, (SUSPEND_CONTEXT_REGS + PT_S9)(a0)
42	REG_S	s10, (SUSPEND_CONTEXT_REGS + PT_S10)(a0)
43	REG_S	s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)
44
45	/* Save CSRs */
46	csrr	t0, CSR_EPC
47	REG_S	t0, (SUSPEND_CONTEXT_REGS + PT_EPC)(a0)
48	csrr	t0, CSR_STATUS
49	REG_S	t0, (SUSPEND_CONTEXT_REGS + PT_STATUS)(a0)
50	csrr	t0, CSR_TVAL
51	REG_S	t0, (SUSPEND_CONTEXT_REGS + PT_BADADDR)(a0)
52	csrr	t0, CSR_CAUSE
53	REG_S	t0, (SUSPEND_CONTEXT_REGS + PT_CAUSE)(a0)
54
55	/* Return non-zero value */
56	li	a0, 1
57
58	/* Return to C code */
59	ret
60SYM_FUNC_END(__cpu_suspend_enter)
61
62SYM_TYPED_FUNC_START(__cpu_resume_enter)
63	/* Load the global pointer */
64	load_global_pointer
65
66#ifdef CONFIG_MMU
67	/* Save A0 and A1 */
68	add	t0, a0, zero
69	add	t1, a1, zero
70
71	/* Enable MMU */
72	la	a0, swapper_pg_dir
73	XIP_FIXUP_OFFSET a0
74	call	relocate_enable_mmu
75
76	/* Restore A0 and A1 */
77	add	a0, t0, zero
78	add	a1, t1, zero
79#endif
80
81	/* Make A0 point to suspend context */
82	add	a0, a1, zero
83
84	/* Restore CSRs */
85	suspend_restore_csrs
86
87	/* Restore registers (except A0 and T0-T6) */
88	suspend_restore_regs
89
90	/* Return zero value */
91	add	a0, zero, zero
92
93	/* Return to C code */
94	ret
95SYM_FUNC_END(__cpu_resume_enter)
96