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 #include <linux/acpi_io.h> 16 #include <acpi/acpiosxf.h> 17 18 /* 19 * Platforms, like ACPI, may want us to save some memory used by them during 20 * suspend and to restore the contents of this memory during the subsequent 21 * resume. The code below implements a mechanism allowing us to do that. 22 */ 23 24 struct nvs_page { 25 unsigned long phys_start; 26 unsigned int size; 27 void *kaddr; 28 void *data; 29 struct list_head node; 30 }; 31 32 static LIST_HEAD(nvs_list); 33 34 /** 35 * suspend_nvs_register - register platform NVS memory region to save 36 * @start - physical address of the region 37 * @size - size of the region 38 * 39 * The NVS region need not be page-aligned (both ends) and we arrange 40 * things so that the data from page-aligned addresses in this region will 41 * be copied into separate RAM pages. 42 */ 43 int suspend_nvs_register(unsigned long start, unsigned long size) 44 { 45 struct nvs_page *entry, *next; 46 47 while (size > 0) { 48 unsigned int nr_bytes; 49 50 entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL); 51 if (!entry) 52 goto Error; 53 54 list_add_tail(&entry->node, &nvs_list); 55 entry->phys_start = start; 56 nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK); 57 entry->size = (size < nr_bytes) ? size : nr_bytes; 58 59 start += entry->size; 60 size -= entry->size; 61 } 62 return 0; 63 64 Error: 65 list_for_each_entry_safe(entry, next, &nvs_list, node) { 66 list_del(&entry->node); 67 kfree(entry); 68 } 69 return -ENOMEM; 70 } 71 72 /** 73 * suspend_nvs_free - free data pages allocated for saving NVS regions 74 */ 75 void suspend_nvs_free(void) 76 { 77 struct nvs_page *entry; 78 79 list_for_each_entry(entry, &nvs_list, node) 80 if (entry->data) { 81 free_page((unsigned long)entry->data); 82 entry->data = NULL; 83 if (entry->kaddr) { 84 iounmap(entry->kaddr); 85 entry->kaddr = NULL; 86 } 87 } 88 } 89 90 /** 91 * suspend_nvs_alloc - allocate memory necessary for saving NVS regions 92 */ 93 int suspend_nvs_alloc(void) 94 { 95 struct nvs_page *entry; 96 97 list_for_each_entry(entry, &nvs_list, node) { 98 entry->data = (void *)__get_free_page(GFP_KERNEL); 99 if (!entry->data) { 100 suspend_nvs_free(); 101 return -ENOMEM; 102 } 103 } 104 return 0; 105 } 106 107 /** 108 * suspend_nvs_save - save NVS memory regions 109 */ 110 int suspend_nvs_save(void) 111 { 112 struct nvs_page *entry; 113 114 printk(KERN_INFO "PM: Saving platform NVS memory\n"); 115 116 list_for_each_entry(entry, &nvs_list, node) 117 if (entry->data) { 118 entry->kaddr = acpi_os_ioremap(entry->phys_start, 119 entry->size); 120 if (!entry->kaddr) { 121 suspend_nvs_free(); 122 return -ENOMEM; 123 } 124 memcpy(entry->data, entry->kaddr, entry->size); 125 } 126 127 return 0; 128 } 129 130 /** 131 * suspend_nvs_restore - restore NVS memory regions 132 * 133 * This function is going to be called with interrupts disabled, so it 134 * cannot iounmap the virtual addresses used to access the NVS region. 135 */ 136 void suspend_nvs_restore(void) 137 { 138 struct nvs_page *entry; 139 140 printk(KERN_INFO "PM: Restoring platform NVS memory\n"); 141 142 list_for_each_entry(entry, &nvs_list, node) 143 if (entry->data) 144 memcpy(entry->kaddr, entry->data, entry->size); 145 } 146