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 */
18struct 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 */
24static 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 */
39static 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 */
67static 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
87static struct notifier_block mips_pm_notifier_block = {
88	.notifier_call = mips_pm_notifier,
89};
90
91static int __init mips_pm_init(void)
92{
93	return cpu_pm_register_notifier(&mips_pm_notifier_block);
94}
95arch_initcall(mips_pm_init);

 
 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>
18#include <asm/pm.h>
19#include <asm/watch.h>
20
21/* Used by PM helper macros in asm/pm.h */
22struct mips_static_suspend_state mips_static_suspend_state;
23
24/**
25 * mips_cpu_save() - Save general CPU state.
26 * Ensures that general CPU context is saved, notably FPU and DSP.
27 */
28static 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 */
43static 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 */
59	__restore_watch();
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 */
71static 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
91static struct notifier_block mips_pm_notifier_block = {
92	.notifier_call = mips_pm_notifier,
93};
94
95static int __init mips_pm_init(void)
96{
97	return cpu_pm_register_notifier(&mips_pm_notifier_block);
98}
99arch_initcall(mips_pm_init);