2 * linux/kernel/power/hibernate_nvs.c - Routines for handling NVS memory
4 * Copyright (C) 2008,2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 * This file is released under the GPLv2.
10 #include <linux/kernel.h>
11 #include <linux/list.h>
13 #include <linux/suspend.h>
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.
22 unsigned long phys_start
;
26 struct list_head node
;
29 static LIST_HEAD(nvs_list
);
32 * hibernate_nvs_register - register platform NVS memory region to save
33 * @start - physical address of the region
34 * @size - size of the region
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.
40 int hibernate_nvs_register(unsigned long start
, unsigned long size
)
42 struct nvs_page
*entry
, *next
;
45 unsigned int nr_bytes
;
47 entry
= kzalloc(sizeof(struct nvs_page
), GFP_KERNEL
);
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
;
62 list_for_each_entry_safe(entry
, next
, &nvs_list
, node
) {
63 list_del(&entry
->node
);
70 * hibernate_nvs_free - free data pages allocated for saving NVS regions
72 void hibernate_nvs_free(void)
74 struct nvs_page
*entry
;
76 list_for_each_entry(entry
, &nvs_list
, node
)
78 free_page((unsigned long)entry
->data
);
81 iounmap(entry
->kaddr
);
88 * hibernate_nvs_alloc - allocate memory necessary for saving NVS regions
90 int hibernate_nvs_alloc(void)
92 struct nvs_page
*entry
;
94 list_for_each_entry(entry
, &nvs_list
, node
) {
95 entry
->data
= (void *)__get_free_page(GFP_KERNEL
);
105 * hibernate_nvs_save - save NVS memory regions
107 void hibernate_nvs_save(void)
109 struct nvs_page
*entry
;
111 printk(KERN_INFO
"PM: Saving platform NVS memory\n");
113 list_for_each_entry(entry
, &nvs_list
, node
)
115 entry
->kaddr
= ioremap(entry
->phys_start
, entry
->size
);
116 memcpy(entry
->data
, entry
->kaddr
, entry
->size
);
121 * hibernate_nvs_restore - restore NVS memory regions
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.
126 void hibernate_nvs_restore(void)
128 struct nvs_page
*entry
;
130 printk(KERN_INFO
"PM: Restoring platform NVS memory\n");
132 list_for_each_entry(entry
, &nvs_list
, node
)
134 memcpy(entry
->kaddr
, entry
->data
, entry
->size
);
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