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b1d4c6ca JH |
1 | /* |
2 | * Copyright (C) 2014 Imagination Technologies Ltd. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License as published by the | |
6 | * Free Software Foundation; either version 2 of the License, or (at your | |
7 | * option) any later version. | |
8 | * | |
9 | * CPU PM notifiers for saving/restoring general CPU state. | |
10 | */ | |
11 | ||
12 | #include <linux/cpu_pm.h> | |
13 | #include <linux/init.h> | |
14 | ||
15 | #include <asm/dsp.h> | |
16 | #include <asm/fpu.h> | |
17 | #include <asm/mmu_context.h> | |
74e91335 | 18 | #include <asm/pm.h> |
b1d4c6ca JH |
19 | #include <asm/watch.h> |
20 | ||
74e91335 JH |
21 | /* Used by PM helper macros in asm/pm.h */ |
22 | struct mips_static_suspend_state mips_static_suspend_state; | |
23 | ||
b1d4c6ca JH |
24 | /** |
25 | * mips_cpu_save() - Save general CPU state. | |
26 | * Ensures that general CPU context is saved, notably FPU and DSP. | |
27 | */ | |
28 | static int mips_cpu_save(void) | |
29 | { | |
30 | /* Save FPU state */ | |
31 | lose_fpu(1); | |
32 | ||
33 | /* Save DSP state */ | |
34 | save_dsp(current); | |
35 | ||
36 | return 0; | |
37 | } | |
38 | ||
39 | /** | |
40 | * mips_cpu_restore() - Restore general CPU state. | |
41 | * Restores important CPU context. | |
42 | */ | |
43 | static void mips_cpu_restore(void) | |
44 | { | |
45 | unsigned int cpu = smp_processor_id(); | |
46 | ||
47 | /* Restore ASID */ | |
48 | if (current->mm) | |
49 | write_c0_entryhi(cpu_asid(cpu, current->mm)); | |
50 | ||
51 | /* Restore DSP state */ | |
52 | restore_dsp(current); | |
53 | ||
54 | /* Restore UserLocal */ | |
55 | if (cpu_has_userlocal) | |
56 | write_c0_userlocal(current_thread_info()->tp_value); | |
57 | ||
58 | /* Restore watch registers */ | |
a7e89326 | 59 | __restore_watch(current); |
b1d4c6ca JH |
60 | } |
61 | ||
62 | /** | |
63 | * mips_pm_notifier() - Notifier for preserving general CPU context. | |
64 | * @self: Notifier block. | |
65 | * @cmd: CPU PM event. | |
66 | * @v: Private data (unused). | |
67 | * | |
68 | * This is called when a CPU power management event occurs, and is used to | |
69 | * ensure that important CPU context is preserved across a CPU power down. | |
70 | */ | |
71 | static int mips_pm_notifier(struct notifier_block *self, unsigned long cmd, | |
72 | void *v) | |
73 | { | |
74 | int ret; | |
75 | ||
76 | switch (cmd) { | |
77 | case CPU_PM_ENTER: | |
78 | ret = mips_cpu_save(); | |
79 | if (ret) | |
80 | return NOTIFY_STOP; | |
81 | break; | |
82 | case CPU_PM_ENTER_FAILED: | |
83 | case CPU_PM_EXIT: | |
84 | mips_cpu_restore(); | |
85 | break; | |
86 | } | |
87 | ||
88 | return NOTIFY_OK; | |
89 | } | |
90 | ||
91 | static struct notifier_block mips_pm_notifier_block = { | |
92 | .notifier_call = mips_pm_notifier, | |
93 | }; | |
94 | ||
95 | static int __init mips_pm_init(void) | |
96 | { | |
97 | return cpu_pm_register_notifier(&mips_pm_notifier_block); | |
98 | } | |
99 | arch_initcall(mips_pm_init); |