1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2004, 2013 Intel Corporation 4 * Author: Naveen B S <naveen.b.s@intel.com> 5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 6 * 7 * All rights reserved. 8 * 9 * ACPI based HotPlug driver that supports Memory Hotplug 10 * This driver fields notifications from firmware for memory add 11 * and remove operations and alerts the VM of the affected memory 12 * ranges. 13 */ 14 15 #include <linux/acpi.h> 16 #include <linux/memory.h> 17 #include <linux/memory_hotplug.h> 18 19 #include "internal.h" 20 21 #define ACPI_MEMORY_DEVICE_CLASS "memory" 22 #define ACPI_MEMORY_DEVICE_HID "PNP0C80" 23 #define ACPI_MEMORY_DEVICE_NAME "Hotplug Mem Device" 24 25 static const struct acpi_device_id memory_device_ids[] = { 26 {ACPI_MEMORY_DEVICE_HID, 0}, 27 {"", 0}, 28 }; 29 30 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY 31 32 static int acpi_memory_device_add(struct acpi_device *device, 33 const struct acpi_device_id *not_used); 34 static void acpi_memory_device_remove(struct acpi_device *device); 35 36 static struct acpi_scan_handler memory_device_handler = { 37 .ids = memory_device_ids, 38 .attach = acpi_memory_device_add, 39 .detach = acpi_memory_device_remove, 40 .hotplug = { 41 .enabled = true, 42 }, 43 }; 44 45 struct acpi_memory_info { 46 struct list_head list; 47 u64 start_addr; /* Memory Range start physical addr */ 48 u64 length; /* Memory Range length */ 49 unsigned short caching; /* memory cache attribute */ 50 unsigned short write_protect; /* memory read/write attribute */ 51 unsigned int enabled:1; 52 }; 53 54 struct acpi_memory_device { 55 struct acpi_device *device; 56 struct list_head res_list; 57 int mgid; 58 }; 59 60 static acpi_status 61 acpi_memory_get_resource(struct acpi_resource *resource, void *context) 62 { 63 struct acpi_memory_device *mem_device = context; 64 struct acpi_resource_address64 address64; 65 struct acpi_memory_info *info, *new; 66 acpi_status status; 67 68 status = acpi_resource_to_address64(resource, &address64); 69 if (ACPI_FAILURE(status) || 70 (address64.resource_type != ACPI_MEMORY_RANGE)) 71 return AE_OK; 72 73 list_for_each_entry(info, &mem_device->res_list, list) { 74 /* Can we combine the resource range information? */ 75 if ((info->caching == address64.info.mem.caching) && 76 (info->write_protect == address64.info.mem.write_protect) && 77 (info->start_addr + info->length == address64.address.minimum)) { 78 info->length += address64.address.address_length; 79 return AE_OK; 80 } 81 } 82 83 new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL); 84 if (!new) 85 return AE_ERROR; 86 87 INIT_LIST_HEAD(&new->list); 88 new->caching = address64.info.mem.caching; 89 new->write_protect = address64.info.mem.write_protect; 90 new->start_addr = address64.address.minimum; 91 new->length = address64.address.address_length; 92 list_add_tail(&new->list, &mem_device->res_list); 93 94 return AE_OK; 95 } 96 97 static void 98 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device) 99 { 100 struct acpi_memory_info *info, *n; 101 102 list_for_each_entry_safe(info, n, &mem_device->res_list, list) 103 kfree(info); 104 INIT_LIST_HEAD(&mem_device->res_list); 105 } 106 107 static int 108 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device) 109 { 110 acpi_status status; 111 112 if (!list_empty(&mem_device->res_list)) 113 return 0; 114 115 status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS, 116 acpi_memory_get_resource, mem_device); 117 if (ACPI_FAILURE(status)) { 118 acpi_memory_free_device_resources(mem_device); 119 return -EINVAL; 120 } 121 122 return 0; 123 } 124 125 static int acpi_memory_check_device(struct acpi_memory_device *mem_device) 126 { 127 unsigned long long current_status; 128 129 /* Get device present/absent information from the _STA */ 130 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, 131 METHOD_NAME__STA, NULL, 132 ¤t_status))) 133 return -ENODEV; 134 /* 135 * Check for device status. Device should be 136 * present/enabled/functioning. 137 */ 138 if (!((current_status & ACPI_STA_DEVICE_PRESENT) 139 && (current_status & ACPI_STA_DEVICE_ENABLED) 140 && (current_status & ACPI_STA_DEVICE_FUNCTIONING))) 141 return -ENODEV; 142 143 return 0; 144 } 145 146 static int acpi_bind_memblk(struct memory_block *mem, void *arg) 147 { 148 return acpi_bind_one(&mem->dev, arg); 149 } 150 151 static int acpi_bind_memory_blocks(struct acpi_memory_info *info, 152 struct acpi_device *adev) 153 { 154 return walk_memory_blocks(info->start_addr, info->length, adev, 155 acpi_bind_memblk); 156 } 157 158 static int acpi_unbind_memblk(struct memory_block *mem, void *arg) 159 { 160 acpi_unbind_one(&mem->dev); 161 return 0; 162 } 163 164 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info) 165 { 166 walk_memory_blocks(info->start_addr, info->length, NULL, 167 acpi_unbind_memblk); 168 } 169 170 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) 171 { 172 acpi_handle handle = mem_device->device->handle; 173 mhp_t mhp_flags = MHP_NID_IS_MGID; 174 int result, num_enabled = 0; 175 struct acpi_memory_info *info; 176 u64 total_length = 0; 177 int node, mgid; 178 179 node = acpi_get_node(handle); 180 181 list_for_each_entry(info, &mem_device->res_list, list) { 182 if (!info->length) 183 continue; 184 /* We want a single node for the whole memory group */ 185 if (node < 0) 186 node = memory_add_physaddr_to_nid(info->start_addr); 187 total_length += info->length; 188 } 189 190 if (!total_length) { 191 dev_err(&mem_device->device->dev, "device is empty\n"); 192 return -EINVAL; 193 } 194 195 mgid = memory_group_register_static(node, PFN_UP(total_length)); 196 if (mgid < 0) 197 return mgid; 198 mem_device->mgid = mgid; 199 200 /* 201 * Tell the VM there is more memory here... 202 * Note: Assume that this function returns zero on success 203 * We don't have memory-hot-add rollback function,now. 204 * (i.e. memory-hot-remove function) 205 */ 206 list_for_each_entry(info, &mem_device->res_list, list) { 207 /* 208 * If the memory block size is zero, please ignore it. 209 * Don't try to do the following memory hotplug flowchart. 210 */ 211 if (!info->length) 212 continue; 213 214 mhp_flags |= MHP_MEMMAP_ON_MEMORY; 215 result = __add_memory(mgid, info->start_addr, info->length, 216 mhp_flags); 217 218 /* 219 * If the memory block has been used by the kernel, add_memory() 220 * returns -EEXIST. If add_memory() returns the other error, it 221 * means that this memory block is not used by the kernel. 222 */ 223 if (result && result != -EEXIST) 224 continue; 225 226 result = acpi_bind_memory_blocks(info, mem_device->device); 227 if (result) { 228 acpi_unbind_memory_blocks(info); 229 return -ENODEV; 230 } 231 232 info->enabled = 1; 233 234 /* 235 * Add num_enable even if add_memory() returns -EEXIST, so the 236 * device is bound to this driver. 237 */ 238 num_enabled++; 239 } 240 if (!num_enabled) { 241 dev_err(&mem_device->device->dev, "add_memory failed\n"); 242 return -EINVAL; 243 } 244 /* 245 * Sometimes the memory device will contain several memory blocks. 246 * When one memory block is hot-added to the system memory, it will 247 * be regarded as a success. 248 * Otherwise if the last memory block can't be hot-added to the system 249 * memory, it will be failure and the memory device can't be bound with 250 * driver. 251 */ 252 return 0; 253 } 254 255 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device) 256 { 257 struct acpi_memory_info *info, *n; 258 259 list_for_each_entry_safe(info, n, &mem_device->res_list, list) { 260 if (!info->enabled) 261 continue; 262 263 acpi_unbind_memory_blocks(info); 264 __remove_memory(info->start_addr, info->length); 265 list_del(&info->list); 266 kfree(info); 267 } 268 } 269 270 static void acpi_memory_device_free(struct acpi_memory_device *mem_device) 271 { 272 if (!mem_device) 273 return; 274 275 /* In case we succeeded adding *some* memory, unregistering fails. */ 276 if (mem_device->mgid >= 0) 277 memory_group_unregister(mem_device->mgid); 278 279 acpi_memory_free_device_resources(mem_device); 280 mem_device->device->driver_data = NULL; 281 kfree(mem_device); 282 } 283 284 static int acpi_memory_device_add(struct acpi_device *device, 285 const struct acpi_device_id *not_used) 286 { 287 struct acpi_memory_device *mem_device; 288 int result; 289 290 if (!device) 291 return -EINVAL; 292 293 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); 294 if (!mem_device) 295 return -ENOMEM; 296 297 INIT_LIST_HEAD(&mem_device->res_list); 298 mem_device->device = device; 299 mem_device->mgid = -1; 300 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME); 301 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS); 302 device->driver_data = mem_device; 303 304 /* Get the range from the _CRS */ 305 result = acpi_memory_get_device_resources(mem_device); 306 if (result) { 307 device->driver_data = NULL; 308 kfree(mem_device); 309 return result; 310 } 311 312 result = acpi_memory_check_device(mem_device); 313 if (result) { 314 acpi_memory_device_free(mem_device); 315 return 0; 316 } 317 318 result = acpi_memory_enable_device(mem_device); 319 if (result) { 320 dev_err(&device->dev, "acpi_memory_enable_device() error\n"); 321 acpi_memory_device_free(mem_device); 322 return result; 323 } 324 325 dev_dbg(&device->dev, "Memory device configured by ACPI\n"); 326 return 1; 327 } 328 329 static void acpi_memory_device_remove(struct acpi_device *device) 330 { 331 struct acpi_memory_device *mem_device; 332 333 if (!device || !acpi_driver_data(device)) 334 return; 335 336 mem_device = acpi_driver_data(device); 337 acpi_memory_remove_memory(mem_device); 338 acpi_memory_device_free(mem_device); 339 } 340 341 static bool __initdata acpi_no_memhotplug; 342 343 void __init acpi_memory_hotplug_init(void) 344 { 345 if (acpi_no_memhotplug) { 346 memory_device_handler.attach = NULL; 347 acpi_scan_add_handler(&memory_device_handler); 348 return; 349 } 350 acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory"); 351 } 352 353 static int __init disable_acpi_memory_hotplug(char *str) 354 { 355 acpi_no_memhotplug = true; 356 return 1; 357 } 358 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug); 359 360 #else 361 362 static struct acpi_scan_handler memory_device_handler = { 363 .ids = memory_device_ids, 364 }; 365 366 void __init acpi_memory_hotplug_init(void) 367 { 368 acpi_scan_add_handler(&memory_device_handler); 369 } 370 371 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */ 372