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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/slab.h> |
14 | #include <linux/suspend.h> |
15 | |
16 | /* |
17 | * Platforms, like ACPI, may want us to save some memory used by them during |
18 | * suspend and to restore the contents of this memory during the subsequent |
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 | /** |
33 | * suspend_nvs_register - register platform NVS memory region to save |
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 | */ |
41 | int suspend_nvs_register(unsigned long start, unsigned long size) |
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 | /** |
71 | * suspend_nvs_free - free data pages allocated for saving NVS regions |
72 | */ |
73 | void suspend_nvs_free(void) |
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 | /** |
89 | * suspend_nvs_alloc - allocate memory necessary for saving NVS regions |
90 | */ |
91 | int suspend_nvs_alloc(void) |
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) { |
98 | suspend_nvs_free(); |
99 | return -ENOMEM; |
100 | } |
101 | } |
102 | return 0; |
103 | } |
104 | |
105 | /** |
106 | * suspend_nvs_save - save NVS memory regions |
107 | */ |
108 | void suspend_nvs_save(void) |
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 | /** |
122 | * suspend_nvs_restore - restore NVS memory regions |
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 | */ |
127 | void suspend_nvs_restore(void) |
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 | } |
137 |
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