1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * nvs.c - Routines for saving and restoring ACPI NVS memory region
4 *
5 * Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
6 */
7
8 #define pr_fmt(fmt) "ACPI: PM: " fmt
9
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/list.h>
13 #include <linux/mm.h>
14 #include <linux/slab.h>
15 #include <linux/acpi.h>
16
17 #include "internal.h"
18
19 /* ACPI NVS regions, APEI may use it */
20
21 struct nvs_region {
22 __u64 phys_start;
23 __u64 size;
24 struct list_head node;
25 };
26
27 static LIST_HEAD(nvs_region_list);
28
29 #ifdef CONFIG_ACPI_SLEEP
30 static int suspend_nvs_register(unsigned long start, unsigned long size);
31 #else
suspend_nvs_register(unsigned long a,unsigned long b)32 static inline int suspend_nvs_register(unsigned long a, unsigned long b)
33 {
34 return 0;
35 }
36 #endif
37
acpi_nvs_register(__u64 start,__u64 size)38 int acpi_nvs_register(__u64 start, __u64 size)
39 {
40 struct nvs_region *region;
41
42 region = kmalloc(sizeof(*region), GFP_KERNEL);
43 if (!region)
44 return -ENOMEM;
45 region->phys_start = start;
46 region->size = size;
47 list_add_tail(®ion->node, &nvs_region_list);
48
49 return suspend_nvs_register(start, size);
50 }
51
acpi_nvs_for_each_region(int (* func)(__u64 start,__u64 size,void * data),void * data)52 int acpi_nvs_for_each_region(int (*func)(__u64 start, __u64 size, void *data),
53 void *data)
54 {
55 int rc;
56 struct nvs_region *region;
57
58 list_for_each_entry(region, &nvs_region_list, node) {
59 rc = func(region->phys_start, region->size, data);
60 if (rc)
61 return rc;
62 }
63
64 return 0;
65 }
66
67
68 #ifdef CONFIG_ACPI_SLEEP
69 /*
70 * Platforms, like ACPI, may want us to save some memory used by them during
71 * suspend and to restore the contents of this memory during the subsequent
72 * resume. The code below implements a mechanism allowing us to do that.
73 */
74
75 struct nvs_page {
76 unsigned long phys_start;
77 unsigned int size;
78 void *kaddr;
79 void *data;
80 bool unmap;
81 struct list_head node;
82 };
83
84 static LIST_HEAD(nvs_list);
85
86 /**
87 * suspend_nvs_register - register platform NVS memory region to save
88 * @start: Physical address of the region.
89 * @size: Size of the region.
90 *
91 * The NVS region need not be page-aligned (both ends) and we arrange
92 * things so that the data from page-aligned addresses in this region will
93 * be copied into separate RAM pages.
94 */
suspend_nvs_register(unsigned long start,unsigned long size)95 static int suspend_nvs_register(unsigned long start, unsigned long size)
96 {
97 struct nvs_page *entry, *next;
98
99 pr_info("Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n",
100 start, start + size - 1, size);
101
102 while (size > 0) {
103 unsigned int nr_bytes;
104
105 entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);
106 if (!entry)
107 goto Error;
108
109 list_add_tail(&entry->node, &nvs_list);
110 entry->phys_start = start;
111 nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK);
112 entry->size = (size < nr_bytes) ? size : nr_bytes;
113
114 start += entry->size;
115 size -= entry->size;
116 }
117 return 0;
118
119 Error:
120 list_for_each_entry_safe(entry, next, &nvs_list, node) {
121 list_del(&entry->node);
122 kfree(entry);
123 }
124 return -ENOMEM;
125 }
126
127 /**
128 * suspend_nvs_free - free data pages allocated for saving NVS regions
129 */
suspend_nvs_free(void)130 void suspend_nvs_free(void)
131 {
132 struct nvs_page *entry;
133
134 list_for_each_entry(entry, &nvs_list, node)
135 if (entry->data) {
136 free_page((unsigned long)entry->data);
137 entry->data = NULL;
138 if (entry->kaddr) {
139 if (entry->unmap) {
140 iounmap(entry->kaddr);
141 entry->unmap = false;
142 } else {
143 acpi_os_unmap_iomem(entry->kaddr,
144 entry->size);
145 }
146 entry->kaddr = NULL;
147 }
148 }
149 }
150
151 /**
152 * suspend_nvs_alloc - allocate memory necessary for saving NVS regions
153 */
suspend_nvs_alloc(void)154 int suspend_nvs_alloc(void)
155 {
156 struct nvs_page *entry;
157
158 list_for_each_entry(entry, &nvs_list, node) {
159 entry->data = (void *)__get_free_page(GFP_KERNEL);
160 if (!entry->data) {
161 suspend_nvs_free();
162 return -ENOMEM;
163 }
164 }
165 return 0;
166 }
167
168 /**
169 * suspend_nvs_save - save NVS memory regions
170 */
suspend_nvs_save(void)171 int suspend_nvs_save(void)
172 {
173 struct nvs_page *entry;
174
175 pr_info("Saving platform NVS memory\n");
176
177 list_for_each_entry(entry, &nvs_list, node)
178 if (entry->data) {
179 unsigned long phys = entry->phys_start;
180 unsigned int size = entry->size;
181
182 entry->kaddr = acpi_os_get_iomem(phys, size);
183 if (!entry->kaddr) {
184 entry->kaddr = acpi_os_ioremap(phys, size);
185 entry->unmap = !!entry->kaddr;
186 }
187 if (!entry->kaddr) {
188 suspend_nvs_free();
189 return -ENOMEM;
190 }
191 memcpy(entry->data, entry->kaddr, entry->size);
192 }
193
194 return 0;
195 }
196
197 /**
198 * suspend_nvs_restore - restore NVS memory regions
199 *
200 * This function is going to be called with interrupts disabled, so it
201 * cannot iounmap the virtual addresses used to access the NVS region.
202 */
suspend_nvs_restore(void)203 void suspend_nvs_restore(void)
204 {
205 struct nvs_page *entry;
206
207 pr_info("Restoring platform NVS memory\n");
208
209 list_for_each_entry(entry, &nvs_list, node)
210 if (entry->data)
211 memcpy(entry->kaddr, entry->data, entry->size);
212 }
213 #endif
214