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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
b1d4c6ca JH |
2 | /* |
3 | * Copyright (C) 2014 Imagination Technologies Ltd. | |
4 | * | |
b1d4c6ca JH |
5 | * CPU PM notifiers for saving/restoring general CPU state. |
6 | */ | |
7 | ||
8 | #include <linux/cpu_pm.h> | |
9 | #include <linux/init.h> | |
10 | ||
11 | #include <asm/dsp.h> | |
12 | #include <asm/fpu.h> | |
13 | #include <asm/mmu_context.h> | |
74e91335 | 14 | #include <asm/pm.h> |
b1d4c6ca JH |
15 | #include <asm/watch.h> |
16 | ||
74e91335 JH |
17 | /* Used by PM helper macros in asm/pm.h */ |
18 | struct mips_static_suspend_state mips_static_suspend_state; | |
19 | ||
b1d4c6ca JH |
20 | /** |
21 | * mips_cpu_save() - Save general CPU state. | |
22 | * Ensures that general CPU context is saved, notably FPU and DSP. | |
23 | */ | |
24 | static int mips_cpu_save(void) | |
25 | { | |
26 | /* Save FPU state */ | |
27 | lose_fpu(1); | |
28 | ||
29 | /* Save DSP state */ | |
30 | save_dsp(current); | |
31 | ||
32 | return 0; | |
33 | } | |
34 | ||
35 | /** | |
36 | * mips_cpu_restore() - Restore general CPU state. | |
37 | * Restores important CPU context. | |
38 | */ | |
39 | static void mips_cpu_restore(void) | |
40 | { | |
41 | unsigned int cpu = smp_processor_id(); | |
42 | ||
43 | /* Restore ASID */ | |
44 | if (current->mm) | |
45 | write_c0_entryhi(cpu_asid(cpu, current->mm)); | |
46 | ||
47 | /* Restore DSP state */ | |
48 | restore_dsp(current); | |
49 | ||
50 | /* Restore UserLocal */ | |
51 | if (cpu_has_userlocal) | |
52 | write_c0_userlocal(current_thread_info()->tp_value); | |
53 | ||
54 | /* Restore watch registers */ | |
a7e89326 | 55 | __restore_watch(current); |
b1d4c6ca JH |
56 | } |
57 | ||
58 | /** | |
59 | * mips_pm_notifier() - Notifier for preserving general CPU context. | |
60 | * @self: Notifier block. | |
61 | * @cmd: CPU PM event. | |
62 | * @v: Private data (unused). | |
63 | * | |
64 | * This is called when a CPU power management event occurs, and is used to | |
65 | * ensure that important CPU context is preserved across a CPU power down. | |
66 | */ | |
67 | static int mips_pm_notifier(struct notifier_block *self, unsigned long cmd, | |
68 | void *v) | |
69 | { | |
70 | int ret; | |
71 | ||
72 | switch (cmd) { | |
73 | case CPU_PM_ENTER: | |
74 | ret = mips_cpu_save(); | |
75 | if (ret) | |
76 | return NOTIFY_STOP; | |
77 | break; | |
78 | case CPU_PM_ENTER_FAILED: | |
79 | case CPU_PM_EXIT: | |
80 | mips_cpu_restore(); | |
81 | break; | |
82 | } | |
83 | ||
84 | return NOTIFY_OK; | |
85 | } | |
86 | ||
87 | static struct notifier_block mips_pm_notifier_block = { | |
88 | .notifier_call = mips_pm_notifier, | |
89 | }; | |
90 | ||
91 | static int __init mips_pm_init(void) | |
92 | { | |
93 | return cpu_pm_register_notifier(&mips_pm_notifier_block); | |
94 | } | |
95 | arch_initcall(mips_pm_init); |