1 /* 2 * nvs.c - Routines for saving and restoring ACPI NVS memory region 3 * 4 * Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. 5 * 6 * This file is released under the GPLv2. 7 */ 8 9 #include <linux/io.h> 10 #include <linux/kernel.h> 11 #include <linux/list.h> 12 #include <linux/mm.h> 13 #include <linux/slab.h> 14 #include <linux/acpi.h> 15 16 #include "internal.h" 17 18 /* ACPI NVS regions, APEI may use it */ 19 20 struct nvs_region { 21 __u64 phys_start; 22 __u64 size; 23 struct list_head node; 24 }; 25 26 static LIST_HEAD(nvs_region_list); 27 28 #ifdef CONFIG_ACPI_SLEEP 29 static int suspend_nvs_register(unsigned long start, unsigned long size); 30 #else 31 static inline int suspend_nvs_register(unsigned long a, unsigned long b) 32 { 33 return 0; 34 } 35 #endif 36 37 int acpi_nvs_register(__u64 start, __u64 size) 38 { 39 struct nvs_region *region; 40 41 region = kmalloc(sizeof(*region), GFP_KERNEL); 42 if (!region) 43 return -ENOMEM; 44 region->phys_start = start; 45 region->size = size; 46 list_add_tail(®ion->node, &nvs_region_list); 47 48 return suspend_nvs_register(start, size); 49 } 50 51 int acpi_nvs_for_each_region(int (*func)(__u64 start, __u64 size, void *data), 52 void *data) 53 { 54 int rc; 55 struct nvs_region *region; 56 57 list_for_each_entry(region, &nvs_region_list, node) { 58 rc = func(region->phys_start, region->size, data); 59 if (rc) 60 return rc; 61 } 62 63 return 0; 64 } 65 66 67 #ifdef CONFIG_ACPI_SLEEP 68 /* 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. 72 */ 73 74 struct nvs_page { 75 unsigned long phys_start; 76 unsigned int size; 77 void *kaddr; 78 void *data; 79 bool unmap; 80 struct list_head node; 81 }; 82 83 static LIST_HEAD(nvs_list); 84 85 /** 86 * suspend_nvs_register - register platform NVS memory region to save 87 * @start - physical address of the region 88 * @size - size of the region 89 * 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. 93 */ 94 static int suspend_nvs_register(unsigned long start, unsigned long size) 95 { 96 struct nvs_page *entry, *next; 97 98 pr_info("PM: Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n", 99 start, start + size - 1, size); 100 101 while (size > 0) { 102 unsigned int nr_bytes; 103 104 entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL); 105 if (!entry) 106 goto Error; 107 108 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; 112 113 start += entry->size; 114 size -= entry->size; 115 } 116 return 0; 117 118 Error: 119 list_for_each_entry_safe(entry, next, &nvs_list, node) { 120 list_del(&entry->node); 121 kfree(entry); 122 } 123 return -ENOMEM; 124 } 125 126 /** 127 * suspend_nvs_free - free data pages allocated for saving NVS regions 128 */ 129 void suspend_nvs_free(void) 130 { 131 struct nvs_page *entry; 132 133 list_for_each_entry(entry, &nvs_list, node) 134 if (entry->data) { 135 free_page((unsigned long)entry->data); 136 entry->data = NULL; 137 if (entry->kaddr) { 138 if (entry->unmap) { 139 iounmap(entry->kaddr); 140 entry->unmap = false; 141 } else { 142 acpi_os_unmap_memory(entry->kaddr, 143 entry->size); 144 } 145 entry->kaddr = NULL; 146 } 147 } 148 } 149 150 /** 151 * suspend_nvs_alloc - allocate memory necessary for saving NVS regions 152 */ 153 int suspend_nvs_alloc(void) 154 { 155 struct nvs_page *entry; 156 157 list_for_each_entry(entry, &nvs_list, node) { 158 entry->data = (void *)__get_free_page(GFP_KERNEL); 159 if (!entry->data) { 160 suspend_nvs_free(); 161 return -ENOMEM; 162 } 163 } 164 return 0; 165 } 166 167 /** 168 * suspend_nvs_save - save NVS memory regions 169 */ 170 int suspend_nvs_save(void) 171 { 172 struct nvs_page *entry; 173 174 printk(KERN_INFO "PM: Saving platform NVS memory\n"); 175 176 list_for_each_entry(entry, &nvs_list, node) 177 if (entry->data) { 178 unsigned long phys = entry->phys_start; 179 unsigned int size = entry->size; 180 181 entry->kaddr = acpi_os_get_iomem(phys, size); 182 if (!entry->kaddr) { 183 entry->kaddr = acpi_os_ioremap(phys, size); 184 entry->unmap = !!entry->kaddr; 185 } 186 if (!entry->kaddr) { 187 suspend_nvs_free(); 188 return -ENOMEM; 189 } 190 memcpy(entry->data, entry->kaddr, entry->size); 191 } 192 193 return 0; 194 } 195 196 /** 197 * suspend_nvs_restore - restore NVS memory regions 198 * 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. 201 */ 202 void suspend_nvs_restore(void) 203 { 204 struct nvs_page *entry; 205 206 printk(KERN_INFO "PM: Restoring platform NVS memory\n"); 207 208 list_for_each_entry(entry, &nvs_list, node) 209 if (entry->data) 210 memcpy(entry->kaddr, entry->data, entry->size); 211 } 212 #endif 213