1/*
2 * Hibernation support specific for ARM
3 *
4 * Derived from work on ARM hibernation support by:
5 *
6 * Ubuntu project, hibernation support for mach-dove
7 * Copyright (C) 2010 Nokia Corporation (Hiroshi Doyu)
8 * Copyright (C) 2010 Texas Instruments, Inc. (Teerth Reddy et al.)
9 *  https://lkml.org/lkml/2010/6/18/4
10 *  https://lists.linux-foundation.org/pipermail/linux-pm/2010-June/027422.html
11 *  https://patchwork.kernel.org/patch/96442/
12 *
13 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
14 *
15 * License terms: GNU General Public License (GPL) version 2
16 */
17
18#include <linux/mm.h>
19#include <linux/suspend.h>
20#include <asm/system_misc.h>
21#include <asm/idmap.h>
22#include <asm/suspend.h>
23#include <asm/memory.h>
24#include <asm/sections.h>
25#include "reboot.h"
26
27int pfn_is_nosave(unsigned long pfn)
28{
29	unsigned long nosave_begin_pfn = virt_to_pfn(&__nosave_begin);
30	unsigned long nosave_end_pfn = virt_to_pfn(&__nosave_end - 1);
31
32	return (pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn);
33}
34
35void notrace save_processor_state(void)
36{
37	WARN_ON(num_online_cpus() != 1);
38	local_fiq_disable();
39}
40
41void notrace restore_processor_state(void)
42{
43	local_fiq_enable();
44}
45
46/*
47 * Snapshot kernel memory and reset the system.
48 *
49 * swsusp_save() is executed in the suspend finisher so that the CPU
50 * context pointer and memory are part of the saved image, which is
51 * required by the resume kernel image to restart execution from
52 * swsusp_arch_suspend().
53 *
54 * soft_restart is not technically needed, but is used to get success
55 * returned from cpu_suspend.
56 *
57 * When soft reboot completes, the hibernation snapshot is written out.
58 */
59static int notrace arch_save_image(unsigned long unused)
60{
61	int ret;
62
63	ret = swsusp_save();
64	if (ret == 0)
65		_soft_restart(virt_to_phys(cpu_resume), false);
66	return ret;
67}
68
69/*
70 * Save the current CPU state before suspend / poweroff.
71 */
72int notrace swsusp_arch_suspend(void)
73{
74	return cpu_suspend(0, arch_save_image);
75}
76
77/*
78 * Restore page contents for physical pages that were in use during loading
79 * hibernation image.  Switch to idmap_pgd so the physical page tables
80 * are overwritten with the same contents.
81 */
82static void notrace arch_restore_image(void *unused)
83{
84	struct pbe *pbe;
85
86	cpu_switch_mm(idmap_pgd, &init_mm);
87	for (pbe = restore_pblist; pbe; pbe = pbe->next)
88		copy_page(pbe->orig_address, pbe->address);
89
90	_soft_restart(virt_to_phys(cpu_resume), false);
91}
92
93static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata;
94
95/*
96 * Resume from the hibernation image.
97 * Due to the kernel heap / data restore, stack contents change underneath
98 * and that would make function calls impossible; switch to a temporary
99 * stack within the nosave region to avoid that problem.
100 */
101int swsusp_arch_resume(void)
102{
103	call_with_stack(arch_restore_image, 0,
104		resume_stack + ARRAY_SIZE(resume_stack));
105	return 0;
106}
107