1 | // SPDX-License-Identifier: GPL-2.0-or-later |
---|---|
2 | /* |
3 | * Copyright (C) 2014 Imagination Technologies Ltd. |
4 | * |
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> |
14 | #include <asm/pm.h> |
15 | #include <asm/watch.h> |
16 | |
17 | /* Used by PM helper macros in asm/pm.h */ |
18 | struct mips_static_suspend_state mips_static_suspend_state; |
19 | |
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 */ |
55 | __restore_watch(current); |
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(nb: &mips_pm_notifier_block); |
94 | } |
95 | arch_initcall(mips_pm_init); |
96 |