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fce2b111 CH |
1 | /* |
2 | * linux/kernel/power/hibernate_nvs.c - Routines for handling NVS memory | |
3 | * | |
4 | * Copyright (C) 2008,2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. | |
5 | * | |
6 | * This file is released under the GPLv2. | |
7 | */ | |
8 | ||
9 | #include <linux/io.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/list.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/suspend.h> | |
14 | ||
15 | /* | |
16 | * Platforms, like ACPI, may want us to save some memory used by them during | |
17 | * hibernation and to restore the contents of this memory during the subsequent | |
18 | * resume. The code below implements a mechanism allowing us to do that. | |
19 | */ | |
20 | ||
21 | struct nvs_page { | |
22 | unsigned long phys_start; | |
23 | unsigned int size; | |
24 | void *kaddr; | |
25 | void *data; | |
26 | struct list_head node; | |
27 | }; | |
28 | ||
29 | static LIST_HEAD(nvs_list); | |
30 | ||
31 | /** | |
32 | * hibernate_nvs_register - register platform NVS memory region to save | |
33 | * @start - physical address of the region | |
34 | * @size - size of the region | |
35 | * | |
36 | * The NVS region need not be page-aligned (both ends) and we arrange | |
37 | * things so that the data from page-aligned addresses in this region will | |
38 | * be copied into separate RAM pages. | |
39 | */ | |
40 | int hibernate_nvs_register(unsigned long start, unsigned long size) | |
41 | { | |
42 | struct nvs_page *entry, *next; | |
43 | ||
44 | while (size > 0) { | |
45 | unsigned int nr_bytes; | |
46 | ||
47 | entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL); | |
48 | if (!entry) | |
49 | goto Error; | |
50 | ||
51 | list_add_tail(&entry->node, &nvs_list); | |
52 | entry->phys_start = start; | |
53 | nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK); | |
54 | entry->size = (size < nr_bytes) ? size : nr_bytes; | |
55 | ||
56 | start += entry->size; | |
57 | size -= entry->size; | |
58 | } | |
59 | return 0; | |
60 | ||
61 | Error: | |
62 | list_for_each_entry_safe(entry, next, &nvs_list, node) { | |
63 | list_del(&entry->node); | |
64 | kfree(entry); | |
65 | } | |
66 | return -ENOMEM; | |
67 | } | |
68 | ||
69 | /** | |
70 | * hibernate_nvs_free - free data pages allocated for saving NVS regions | |
71 | */ | |
72 | void hibernate_nvs_free(void) | |
73 | { | |
74 | struct nvs_page *entry; | |
75 | ||
76 | list_for_each_entry(entry, &nvs_list, node) | |
77 | if (entry->data) { | |
78 | free_page((unsigned long)entry->data); | |
79 | entry->data = NULL; | |
80 | if (entry->kaddr) { | |
81 | iounmap(entry->kaddr); | |
82 | entry->kaddr = NULL; | |
83 | } | |
84 | } | |
85 | } | |
86 | ||
87 | /** | |
88 | * hibernate_nvs_alloc - allocate memory necessary for saving NVS regions | |
89 | */ | |
90 | int hibernate_nvs_alloc(void) | |
91 | { | |
92 | struct nvs_page *entry; | |
93 | ||
94 | list_for_each_entry(entry, &nvs_list, node) { | |
95 | entry->data = (void *)__get_free_page(GFP_KERNEL); | |
96 | if (!entry->data) { | |
97 | hibernate_nvs_free(); | |
98 | return -ENOMEM; | |
99 | } | |
100 | } | |
101 | return 0; | |
102 | } | |
103 | ||
104 | /** | |
105 | * hibernate_nvs_save - save NVS memory regions | |
106 | */ | |
107 | void hibernate_nvs_save(void) | |
108 | { | |
109 | struct nvs_page *entry; | |
110 | ||
111 | printk(KERN_INFO "PM: Saving platform NVS memory\n"); | |
112 | ||
113 | list_for_each_entry(entry, &nvs_list, node) | |
114 | if (entry->data) { | |
115 | entry->kaddr = ioremap(entry->phys_start, entry->size); | |
116 | memcpy(entry->data, entry->kaddr, entry->size); | |
117 | } | |
118 | } | |
119 | ||
120 | /** | |
121 | * hibernate_nvs_restore - restore NVS memory regions | |
122 | * | |
123 | * This function is going to be called with interrupts disabled, so it | |
124 | * cannot iounmap the virtual addresses used to access the NVS region. | |
125 | */ | |
126 | void hibernate_nvs_restore(void) | |
127 | { | |
128 | struct nvs_page *entry; | |
129 | ||
130 | printk(KERN_INFO "PM: Restoring platform NVS memory\n"); | |
131 | ||
132 | list_for_each_entry(entry, &nvs_list, node) | |
133 | if (entry->data) | |
134 | memcpy(entry->kaddr, entry->data, entry->size); | |
135 | } |