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 <linux/acpi_io.h>
16 #include <acpi/acpiosxf.h>
18 /* ACPI NVS regions, APEI may use it */
23 struct list_head node
;
26 static LIST_HEAD(nvs_region_list
);
28 #ifdef CONFIG_ACPI_SLEEP
29 static int suspend_nvs_register(unsigned long start
, unsigned long size
);
31 static inline int suspend_nvs_register(unsigned long a
, unsigned long b
)
37 int acpi_nvs_register(__u64 start
, __u64 size
)
39 struct nvs_region
*region
;
41 region
= kmalloc(sizeof(*region
), GFP_KERNEL
);
44 region
->phys_start
= start
;
46 list_add_tail(®ion
->node
, &nvs_region_list
);
48 return suspend_nvs_register(start
, size
);
51 int acpi_nvs_for_each_region(int (*func
)(__u64 start
, __u64 size
, void *data
),
55 struct nvs_region
*region
;
57 list_for_each_entry(region
, &nvs_region_list
, node
) {
58 rc
= func(region
->phys_start
, region
->size
, data
);
67 #ifdef CONFIG_ACPI_SLEEP
69 * Platforms, like ACPI, may want us to save some memory used by them during
70 * suspend and to restore the contents of this memory during the subsequent
71 * resume. The code below implements a mechanism allowing us to do that.
75 unsigned long phys_start
;
80 struct list_head node
;
83 static LIST_HEAD(nvs_list
);
86 * suspend_nvs_register - register platform NVS memory region to save
87 * @start - physical address of the region
88 * @size - size of the region
90 * The NVS region need not be page-aligned (both ends) and we arrange
91 * things so that the data from page-aligned addresses in this region will
92 * be copied into separate RAM pages.
94 static int suspend_nvs_register(unsigned long start
, unsigned long size
)
96 struct nvs_page
*entry
, *next
;
98 pr_info("PM: Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n",
99 start
, start
+ size
- 1, size
);
102 unsigned int nr_bytes
;
104 entry
= kzalloc(sizeof(struct nvs_page
), GFP_KERNEL
);
108 list_add_tail(&entry
->node
, &nvs_list
);
109 entry
->phys_start
= start
;
110 nr_bytes
= PAGE_SIZE
- (start
& ~PAGE_MASK
);
111 entry
->size
= (size
< nr_bytes
) ? size
: nr_bytes
;
113 start
+= entry
->size
;
119 list_for_each_entry_safe(entry
, next
, &nvs_list
, node
) {
120 list_del(&entry
->node
);
127 * suspend_nvs_free - free data pages allocated for saving NVS regions
129 void suspend_nvs_free(void)
131 struct nvs_page
*entry
;
133 list_for_each_entry(entry
, &nvs_list
, node
)
135 free_page((unsigned long)entry
->data
);
139 iounmap(entry
->kaddr
);
140 entry
->unmap
= false;
142 acpi_os_unmap_memory(entry
->kaddr
,
151 * suspend_nvs_alloc - allocate memory necessary for saving NVS regions
153 int suspend_nvs_alloc(void)
155 struct nvs_page
*entry
;
157 list_for_each_entry(entry
, &nvs_list
, node
) {
158 entry
->data
= (void *)__get_free_page(GFP_KERNEL
);
168 * suspend_nvs_save - save NVS memory regions
170 int suspend_nvs_save(void)
172 struct nvs_page
*entry
;
174 printk(KERN_INFO
"PM: Saving platform NVS memory\n");
176 list_for_each_entry(entry
, &nvs_list
, node
)
178 unsigned long phys
= entry
->phys_start
;
179 unsigned int size
= entry
->size
;
181 entry
->kaddr
= acpi_os_get_iomem(phys
, size
);
183 entry
->kaddr
= acpi_os_ioremap(phys
, size
);
184 entry
->unmap
= !!entry
->kaddr
;
190 memcpy(entry
->data
, entry
->kaddr
, entry
->size
);
197 * suspend_nvs_restore - restore NVS memory regions
199 * This function is going to be called with interrupts disabled, so it
200 * cannot iounmap the virtual addresses used to access the NVS region.
202 void suspend_nvs_restore(void)
204 struct nvs_page
*entry
;
206 printk(KERN_INFO
"PM: Restoring platform NVS memory\n");
208 list_for_each_entry(entry
, &nvs_list
, node
)
210 memcpy(entry
->kaddr
, entry
->data
, entry
->size
);
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