Commit | Line | Data |
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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> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
fce2b111 CH |
14 | #include <linux/suspend.h> |
15 | ||
16 | /* | |
17 | * Platforms, like ACPI, may want us to save some memory used by them during | |
dd4c4f17 | 18 | * suspend and to restore the contents of this memory during the subsequent |
fce2b111 CH |
19 | * resume. The code below implements a mechanism allowing us to do that. |
20 | */ | |
21 | ||
22 | struct nvs_page { | |
23 | unsigned long phys_start; | |
24 | unsigned int size; | |
25 | void *kaddr; | |
26 | void *data; | |
27 | struct list_head node; | |
28 | }; | |
29 | ||
30 | static LIST_HEAD(nvs_list); | |
31 | ||
32 | /** | |
dd4c4f17 | 33 | * suspend_nvs_register - register platform NVS memory region to save |
fce2b111 CH |
34 | * @start - physical address of the region |
35 | * @size - size of the region | |
36 | * | |
37 | * The NVS region need not be page-aligned (both ends) and we arrange | |
38 | * things so that the data from page-aligned addresses in this region will | |
39 | * be copied into separate RAM pages. | |
40 | */ | |
dd4c4f17 | 41 | int suspend_nvs_register(unsigned long start, unsigned long size) |
fce2b111 CH |
42 | { |
43 | struct nvs_page *entry, *next; | |
44 | ||
45 | while (size > 0) { | |
46 | unsigned int nr_bytes; | |
47 | ||
48 | entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL); | |
49 | if (!entry) | |
50 | goto Error; | |
51 | ||
52 | list_add_tail(&entry->node, &nvs_list); | |
53 | entry->phys_start = start; | |
54 | nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK); | |
55 | entry->size = (size < nr_bytes) ? size : nr_bytes; | |
56 | ||
57 | start += entry->size; | |
58 | size -= entry->size; | |
59 | } | |
60 | return 0; | |
61 | ||
62 | Error: | |
63 | list_for_each_entry_safe(entry, next, &nvs_list, node) { | |
64 | list_del(&entry->node); | |
65 | kfree(entry); | |
66 | } | |
67 | return -ENOMEM; | |
68 | } | |
69 | ||
70 | /** | |
dd4c4f17 | 71 | * suspend_nvs_free - free data pages allocated for saving NVS regions |
fce2b111 | 72 | */ |
dd4c4f17 | 73 | void suspend_nvs_free(void) |
fce2b111 CH |
74 | { |
75 | struct nvs_page *entry; | |
76 | ||
77 | list_for_each_entry(entry, &nvs_list, node) | |
78 | if (entry->data) { | |
79 | free_page((unsigned long)entry->data); | |
80 | entry->data = NULL; | |
81 | if (entry->kaddr) { | |
82 | iounmap(entry->kaddr); | |
83 | entry->kaddr = NULL; | |
84 | } | |
85 | } | |
86 | } | |
87 | ||
88 | /** | |
dd4c4f17 | 89 | * suspend_nvs_alloc - allocate memory necessary for saving NVS regions |
fce2b111 | 90 | */ |
dd4c4f17 | 91 | int suspend_nvs_alloc(void) |
fce2b111 CH |
92 | { |
93 | struct nvs_page *entry; | |
94 | ||
95 | list_for_each_entry(entry, &nvs_list, node) { | |
96 | entry->data = (void *)__get_free_page(GFP_KERNEL); | |
97 | if (!entry->data) { | |
dd4c4f17 | 98 | suspend_nvs_free(); |
fce2b111 CH |
99 | return -ENOMEM; |
100 | } | |
101 | } | |
102 | return 0; | |
103 | } | |
104 | ||
105 | /** | |
dd4c4f17 | 106 | * suspend_nvs_save - save NVS memory regions |
fce2b111 | 107 | */ |
dd4c4f17 | 108 | void suspend_nvs_save(void) |
fce2b111 CH |
109 | { |
110 | struct nvs_page *entry; | |
111 | ||
112 | printk(KERN_INFO "PM: Saving platform NVS memory\n"); | |
113 | ||
114 | list_for_each_entry(entry, &nvs_list, node) | |
115 | if (entry->data) { | |
116 | entry->kaddr = ioremap(entry->phys_start, entry->size); | |
117 | memcpy(entry->data, entry->kaddr, entry->size); | |
118 | } | |
119 | } | |
120 | ||
121 | /** | |
dd4c4f17 | 122 | * suspend_nvs_restore - restore NVS memory regions |
fce2b111 CH |
123 | * |
124 | * This function is going to be called with interrupts disabled, so it | |
125 | * cannot iounmap the virtual addresses used to access the NVS region. | |
126 | */ | |
dd4c4f17 | 127 | void suspend_nvs_restore(void) |
fce2b111 CH |
128 | { |
129 | struct nvs_page *entry; | |
130 | ||
131 | printk(KERN_INFO "PM: Restoring platform NVS memory\n"); | |
132 | ||
133 | list_for_each_entry(entry, &nvs_list, node) | |
134 | if (entry->data) | |
135 | memcpy(entry->kaddr, entry->data, entry->size); | |
136 | } |