summaryrefslogtreecommitdiff
path: root/drivers/acpi/nvs.c
blob: de4fe03873c53e1f89203692dc78d5b703220df7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/*
 * nvs.c - Routines for saving and restoring ACPI NVS memory region
 *
 * Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 *
 * This file is released under the GPLv2.
 */

#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/acpi.h>

#include "internal.h"

/* ACPI NVS regions, APEI may use it */

struct nvs_region {
	__u64 phys_start;
	__u64 size;
	struct list_head node;
};

static LIST_HEAD(nvs_region_list);

#ifdef CONFIG_ACPI_SLEEP
static int suspend_nvs_register(unsigned long start, unsigned long size);
#else
static inline int suspend_nvs_register(unsigned long a, unsigned long b)
{
	return 0;
}
#endif

int acpi_nvs_register(__u64 start, __u64 size)
{
	struct nvs_region *region;

	region = kmalloc(sizeof(*region), GFP_KERNEL);
	if (!region)
		return -ENOMEM;
	region->phys_start = start;
	region->size = size;
	list_add_tail(&region->node, &nvs_region_list);

	return suspend_nvs_register(start, size);
}

int acpi_nvs_for_each_region(int (*func)(__u64 start, __u64 size, void *data),
			     void *data)
{
	int rc;
	struct nvs_region *region;

	list_for_each_entry(region, &nvs_region_list, node) {
		rc = func(region->phys_start, region->size, data);
		if (rc)
			return rc;
	}

	return 0;
}


#ifdef CONFIG_ACPI_SLEEP
/*
 * Platforms, like ACPI, may want us to save some memory used by them during
 * suspend and to restore the contents of this memory during the subsequent
 * resume.  The code below implements a mechanism allowing us to do that.
 */

struct nvs_page {
	unsigned long phys_start;
	unsigned int size;
	void *kaddr;
	void *data;
	bool unmap;
	struct list_head node;
};

static LIST_HEAD(nvs_list);

/**
 *	suspend_nvs_register - register platform NVS memory region to save
 *	@start - physical address of the region
 *	@size - size of the region
 *
 *	The NVS region need not be page-aligned (both ends) and we arrange
 *	things so that the data from page-aligned addresses in this region will
 *	be copied into separate RAM pages.
 */
static int suspend_nvs_register(unsigned long start, unsigned long size)
{
	struct nvs_page *entry, *next;

	pr_info("PM: Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n",
		start, start + size - 1, size);

	while (size > 0) {
		unsigned int nr_bytes;

		entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);
		if (!entry)
			goto Error;

		list_add_tail(&entry->node, &nvs_list);
		entry->phys_start = start;
		nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK);
		entry->size = (size < nr_bytes) ? size : nr_bytes;

		start += entry->size;
		size -= entry->size;
	}
	return 0;

 Error:
	list_for_each_entry_safe(entry, next, &nvs_list, node) {
		list_del(&entry->node);
		kfree(entry);
	}
	return -ENOMEM;
}

/**
 *	suspend_nvs_free - free data pages allocated for saving NVS regions
 */
void suspend_nvs_free(void)
{
	struct nvs_page *entry;

	list_for_each_entry(entry, &nvs_list, node)
		if (entry->data) {
			free_page((unsigned long)entry->data);
			entry->data = NULL;
			if (entry->kaddr) {
				if (entry->unmap) {
					iounmap(entry->kaddr);
					entry->unmap = false;
				} else {
					acpi_os_unmap_memory(entry->kaddr,
							     entry->size);
				}
				entry->kaddr = NULL;
			}
		}
}

/**
 *	suspend_nvs_alloc - allocate memory necessary for saving NVS regions
 */
int suspend_nvs_alloc(void)
{
	struct nvs_page *entry;

	list_for_each_entry(entry, &nvs_list, node) {
		entry->data = (void *)__get_free_page(GFP_KERNEL);
		if (!entry->data) {
			suspend_nvs_free();
			return -ENOMEM;
		}
	}
	return 0;
}

/**
 *	suspend_nvs_save - save NVS memory regions
 */
int suspend_nvs_save(void)
{
	struct nvs_page *entry;

	printk(KERN_INFO "PM: Saving platform NVS memory\n");

	list_for_each_entry(entry, &nvs_list, node)
		if (entry->data) {
			unsigned long phys = entry->phys_start;
			unsigned int size = entry->size;

			entry->kaddr = acpi_os_get_iomem(phys, size);
			if (!entry->kaddr) {
				entry->kaddr = acpi_os_ioremap(phys, size);
				entry->unmap = !!entry->kaddr;
			}
			if (!entry->kaddr) {
				suspend_nvs_free();
				return -ENOMEM;
			}
			memcpy(entry->data, entry->kaddr, entry->size);
		}

	return 0;
}

/**
 *	suspend_nvs_restore - restore NVS memory regions
 *
 *	This function is going to be called with interrupts disabled, so it
 *	cannot iounmap the virtual addresses used to access the NVS region.
 */
void suspend_nvs_restore(void)
{
	struct nvs_page *entry;

	printk(KERN_INFO "PM: Restoring platform NVS memory\n");

	list_for_each_entry(entry, &nvs_list, node)
		if (entry->data)
			memcpy(entry->kaddr, entry->data, entry->size);
}
#endif