2 * nvs.c - Routines for saving and restoring ACPI NVS memory region
4 * Copyright (C) 2008-2011 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/slab.h>
14 #include <linux/acpi.h>
15 #include <acpi/acpiosxf.h>
18 * Platforms, like ACPI, may want us to save some memory used by them during
19 * suspend and to restore the contents of this memory during the subsequent
20 * resume. The code below implements a mechanism allowing us to do that.
24 unsigned long phys_start
;
28 struct list_head node
;
31 static LIST_HEAD(nvs_list
);
34 * suspend_nvs_register - register platform NVS memory region to save
35 * @start - physical address of the region
36 * @size - size of the region
38 * The NVS region need not be page-aligned (both ends) and we arrange
39 * things so that the data from page-aligned addresses in this region will
40 * be copied into separate RAM pages.
42 int suspend_nvs_register(unsigned long start
, unsigned long size
)
44 struct nvs_page
*entry
, *next
;
47 unsigned int nr_bytes
;
49 entry
= kzalloc(sizeof(struct nvs_page
), GFP_KERNEL
);
53 list_add_tail(&entry
->node
, &nvs_list
);
54 entry
->phys_start
= start
;
55 nr_bytes
= PAGE_SIZE
- (start
& ~PAGE_MASK
);
56 entry
->size
= (size
< nr_bytes
) ? size
: nr_bytes
;
64 list_for_each_entry_safe(entry
, next
, &nvs_list
, node
) {
65 list_del(&entry
->node
);
72 * suspend_nvs_free - free data pages allocated for saving NVS regions
74 void suspend_nvs_free(void)
76 struct nvs_page
*entry
;
78 list_for_each_entry(entry
, &nvs_list
, node
)
80 free_page((unsigned long)entry
->data
);
83 acpi_os_unmap_memory(entry
->kaddr
, entry
->size
);
90 * suspend_nvs_alloc - allocate memory necessary for saving NVS regions
92 int suspend_nvs_alloc(void)
94 struct nvs_page
*entry
;
96 list_for_each_entry(entry
, &nvs_list
, node
) {
97 entry
->data
= (void *)__get_free_page(GFP_KERNEL
);
107 * suspend_nvs_save - save NVS memory regions
109 int suspend_nvs_save(void)
111 struct nvs_page
*entry
;
113 printk(KERN_INFO
"PM: Saving platform NVS memory\n");
115 list_for_each_entry(entry
, &nvs_list
, node
)
117 entry
->kaddr
= acpi_os_map_memory(entry
->phys_start
,
123 memcpy(entry
->data
, entry
->kaddr
, entry
->size
);
130 * suspend_nvs_restore - restore NVS memory regions
132 * This function is going to be called with interrupts disabled, so it
133 * cannot iounmap the virtual addresses used to access the NVS region.
135 void suspend_nvs_restore(void)
137 struct nvs_page
*entry
;
139 printk(KERN_INFO
"PM: Restoring platform NVS memory\n");
141 list_for_each_entry(entry
, &nvs_list
, node
)
143 memcpy(entry
->kaddr
, entry
->data
, entry
->size
);