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 |
32 | static inline int suspend_nvs_register(unsigned long a, unsigned long b) |
33 | { |
34 | return 0; |
35 | } |
36 | #endif |
37 | |
38 | int acpi_nvs_register(__u64 start, __u64 size) |
39 | { |
40 | struct nvs_region *region; |
41 | |
42 | region = kmalloc(size: sizeof(*region), GFP_KERNEL); |
43 | if (!region) |
44 | return -ENOMEM; |
45 | region->phys_start = start; |
46 | region->size = size; |
47 | list_add_tail(new: ®ion->node, head: &nvs_region_list); |
48 | |
49 | return suspend_nvs_register(start, size); |
50 | } |
51 | |
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 | */ |
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(size: sizeof(struct nvs_page), GFP_KERNEL); |
106 | if (!entry) |
107 | goto Error; |
108 | |
109 | list_add_tail(new: &entry->node, head: &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: &entry->node); |
122 | kfree(objp: entry); |
123 | } |
124 | return -ENOMEM; |
125 | } |
126 | |
127 | /** |
128 | * suspend_nvs_free - free data pages allocated for saving NVS regions |
129 | */ |
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(addr: entry->kaddr); |
141 | entry->unmap = false; |
142 | } else { |
143 | acpi_os_unmap_iomem(virt: entry->kaddr, |
144 | size: entry->size); |
145 | } |
146 | entry->kaddr = NULL; |
147 | } |
148 | } |
149 | } |
150 | |
151 | /** |
152 | * suspend_nvs_alloc - allocate memory necessary for saving NVS regions |
153 | */ |
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 | */ |
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 | */ |
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 | |