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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * nvs.c - Routines for saving and restoring ACPI NVS memory region4 *5 * Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.6 */7 8#define pr_fmt(fmt) "ACPI: PM: " fmt9 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 21struct nvs_region {22 __u64 phys_start;23 __u64 size;24 struct list_head node;25};26 27static LIST_HEAD(nvs_region_list);28 29#ifdef CONFIG_ACPI_SLEEP30static int suspend_nvs_register(unsigned long start, unsigned long size);31#else32static inline int suspend_nvs_register(unsigned long a, unsigned long b)33{34 return 0;35}36#endif37 38int 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 52int 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_SLEEP69/*70 * Platforms, like ACPI, may want us to save some memory used by them during71 * suspend and to restore the contents of this memory during the subsequent72 * resume. The code below implements a mechanism allowing us to do that.73 */74 75struct 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 84static LIST_HEAD(nvs_list);85 86/**87 * suspend_nvs_register - register platform NVS memory region to save88 * @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 arrange92 * things so that the data from page-aligned addresses in this region will93 * be copied into separate RAM pages.94 */95static 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 regions129 */130void 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 regions153 */154int 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 regions170 */171int 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 regions199 *200 * This function is going to be called with interrupts disabled, so it201 * cannot iounmap the virtual addresses used to access the NVS region.202 */203void 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#endif214