1 /* 2 * Copyright (C) 2004 Intel Corporation <naveen.b.s@intel.com> 3 * 4 * All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or (at 9 * your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 14 * NON INFRINGEMENT. See the GNU General Public License for more 15 * details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 20 * 21 * 22 * ACPI based HotPlug driver that supports Memory Hotplug 23 * This driver fields notifications from firmware for memory add 24 * and remove operations and alerts the VM of the affected memory 25 * ranges. 26 */ 27 28 #include <linux/kernel.h> 29 #include <linux/module.h> 30 #include <linux/init.h> 31 #include <linux/types.h> 32 #include <linux/memory_hotplug.h> 33 #include <acpi/acpi_drivers.h> 34 35 #define ACPI_MEMORY_DEVICE_CLASS "memory" 36 #define ACPI_MEMORY_DEVICE_HID "PNP0C80" 37 #define ACPI_MEMORY_DEVICE_NAME "Hotplug Mem Device" 38 39 #define _COMPONENT ACPI_MEMORY_DEVICE_COMPONENT 40 41 ACPI_MODULE_NAME("acpi_memhotplug"); 42 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>"); 43 MODULE_DESCRIPTION("Hotplug Mem Driver"); 44 MODULE_LICENSE("GPL"); 45 46 /* Memory Device States */ 47 #define MEMORY_INVALID_STATE 0 48 #define MEMORY_POWER_ON_STATE 1 49 #define MEMORY_POWER_OFF_STATE 2 50 51 static int acpi_memory_device_add(struct acpi_device *device); 52 static int acpi_memory_device_remove(struct acpi_device *device, int type); 53 static int acpi_memory_device_start(struct acpi_device *device); 54 55 static const struct acpi_device_id memory_device_ids[] = { 56 {ACPI_MEMORY_DEVICE_HID, 0}, 57 {"", 0}, 58 }; 59 MODULE_DEVICE_TABLE(acpi, memory_device_ids); 60 61 static struct acpi_driver acpi_memory_device_driver = { 62 .name = "acpi_memhotplug", 63 .class = ACPI_MEMORY_DEVICE_CLASS, 64 .ids = memory_device_ids, 65 .ops = { 66 .add = acpi_memory_device_add, 67 .remove = acpi_memory_device_remove, 68 .start = acpi_memory_device_start, 69 }, 70 }; 71 72 struct acpi_memory_info { 73 struct list_head list; 74 u64 start_addr; /* Memory Range start physical addr */ 75 u64 length; /* Memory Range length */ 76 unsigned short caching; /* memory cache attribute */ 77 unsigned short write_protect; /* memory read/write attribute */ 78 unsigned int enabled:1; 79 }; 80 81 struct acpi_memory_device { 82 struct acpi_device * device; 83 unsigned int state; /* State of the memory device */ 84 struct list_head res_list; 85 }; 86 87 static int acpi_hotmem_initialized; 88 89 static acpi_status 90 acpi_memory_get_resource(struct acpi_resource *resource, void *context) 91 { 92 struct acpi_memory_device *mem_device = context; 93 struct acpi_resource_address64 address64; 94 struct acpi_memory_info *info, *new; 95 acpi_status status; 96 97 status = acpi_resource_to_address64(resource, &address64); 98 if (ACPI_FAILURE(status) || 99 (address64.resource_type != ACPI_MEMORY_RANGE)) 100 return AE_OK; 101 102 list_for_each_entry(info, &mem_device->res_list, list) { 103 /* Can we combine the resource range information? */ 104 if ((info->caching == address64.info.mem.caching) && 105 (info->write_protect == address64.info.mem.write_protect) && 106 (info->start_addr + info->length == address64.minimum)) { 107 info->length += address64.address_length; 108 return AE_OK; 109 } 110 } 111 112 new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL); 113 if (!new) 114 return AE_ERROR; 115 116 INIT_LIST_HEAD(&new->list); 117 new->caching = address64.info.mem.caching; 118 new->write_protect = address64.info.mem.write_protect; 119 new->start_addr = address64.minimum; 120 new->length = address64.address_length; 121 list_add_tail(&new->list, &mem_device->res_list); 122 123 return AE_OK; 124 } 125 126 static int 127 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device) 128 { 129 acpi_status status; 130 struct acpi_memory_info *info, *n; 131 132 133 if (!list_empty(&mem_device->res_list)) 134 return 0; 135 136 status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS, 137 acpi_memory_get_resource, mem_device); 138 if (ACPI_FAILURE(status)) { 139 list_for_each_entry_safe(info, n, &mem_device->res_list, list) 140 kfree(info); 141 INIT_LIST_HEAD(&mem_device->res_list); 142 return -EINVAL; 143 } 144 145 return 0; 146 } 147 148 static int 149 acpi_memory_get_device(acpi_handle handle, 150 struct acpi_memory_device **mem_device) 151 { 152 acpi_status status; 153 acpi_handle phandle; 154 struct acpi_device *device = NULL; 155 struct acpi_device *pdevice = NULL; 156 157 158 if (!acpi_bus_get_device(handle, &device) && device) 159 goto end; 160 161 status = acpi_get_parent(handle, &phandle); 162 if (ACPI_FAILURE(status)) { 163 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent")); 164 return -EINVAL; 165 } 166 167 /* Get the parent device */ 168 status = acpi_bus_get_device(phandle, &pdevice); 169 if (ACPI_FAILURE(status)) { 170 ACPI_EXCEPTION((AE_INFO, status, "Cannot get acpi bus device")); 171 return -EINVAL; 172 } 173 174 /* 175 * Now add the notified device. This creates the acpi_device 176 * and invokes .add function 177 */ 178 status = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE); 179 if (ACPI_FAILURE(status)) { 180 ACPI_EXCEPTION((AE_INFO, status, "Cannot add acpi bus")); 181 return -EINVAL; 182 } 183 184 end: 185 *mem_device = acpi_driver_data(device); 186 if (!(*mem_device)) { 187 printk(KERN_ERR "\n driver data not found"); 188 return -ENODEV; 189 } 190 191 return 0; 192 } 193 194 static int acpi_memory_check_device(struct acpi_memory_device *mem_device) 195 { 196 unsigned long long current_status; 197 198 /* Get device present/absent information from the _STA */ 199 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA", 200 NULL, ¤t_status))) 201 return -ENODEV; 202 /* 203 * Check for device status. Device should be 204 * present/enabled/functioning. 205 */ 206 if (!((current_status & ACPI_STA_DEVICE_PRESENT) 207 && (current_status & ACPI_STA_DEVICE_ENABLED) 208 && (current_status & ACPI_STA_DEVICE_FUNCTIONING))) 209 return -ENODEV; 210 211 return 0; 212 } 213 214 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) 215 { 216 int result, num_enabled = 0; 217 struct acpi_memory_info *info; 218 int node; 219 220 221 /* Get the range from the _CRS */ 222 result = acpi_memory_get_device_resources(mem_device); 223 if (result) { 224 printk(KERN_ERR PREFIX "get_device_resources failed\n"); 225 mem_device->state = MEMORY_INVALID_STATE; 226 return result; 227 } 228 229 node = acpi_get_node(mem_device->device->handle); 230 /* 231 * Tell the VM there is more memory here... 232 * Note: Assume that this function returns zero on success 233 * We don't have memory-hot-add rollback function,now. 234 * (i.e. memory-hot-remove function) 235 */ 236 list_for_each_entry(info, &mem_device->res_list, list) { 237 if (info->enabled) { /* just sanity check...*/ 238 num_enabled++; 239 continue; 240 } 241 242 if (node < 0) 243 node = memory_add_physaddr_to_nid(info->start_addr); 244 245 result = add_memory(node, info->start_addr, info->length); 246 if (result) 247 continue; 248 info->enabled = 1; 249 num_enabled++; 250 } 251 if (!num_enabled) { 252 printk(KERN_ERR PREFIX "add_memory failed\n"); 253 mem_device->state = MEMORY_INVALID_STATE; 254 return -EINVAL; 255 } 256 257 return result; 258 } 259 260 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device) 261 { 262 acpi_status status; 263 struct acpi_object_list arg_list; 264 union acpi_object arg; 265 unsigned long long current_status; 266 267 268 /* Issue the _EJ0 command */ 269 arg_list.count = 1; 270 arg_list.pointer = &arg; 271 arg.type = ACPI_TYPE_INTEGER; 272 arg.integer.value = 1; 273 status = acpi_evaluate_object(mem_device->device->handle, 274 "_EJ0", &arg_list, NULL); 275 /* Return on _EJ0 failure */ 276 if (ACPI_FAILURE(status)) { 277 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed")); 278 return -ENODEV; 279 } 280 281 /* Evalute _STA to check if the device is disabled */ 282 status = acpi_evaluate_integer(mem_device->device->handle, "_STA", 283 NULL, ¤t_status); 284 if (ACPI_FAILURE(status)) 285 return -ENODEV; 286 287 /* Check for device status. Device should be disabled */ 288 if (current_status & ACPI_STA_DEVICE_ENABLED) 289 return -EINVAL; 290 291 return 0; 292 } 293 294 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) 295 { 296 int result; 297 struct acpi_memory_info *info, *n; 298 299 300 /* 301 * Ask the VM to offline this memory range. 302 * Note: Assume that this function returns zero on success 303 */ 304 list_for_each_entry_safe(info, n, &mem_device->res_list, list) { 305 if (info->enabled) { 306 result = remove_memory(info->start_addr, info->length); 307 if (result) 308 return result; 309 } 310 kfree(info); 311 } 312 313 /* Power-off and eject the device */ 314 result = acpi_memory_powerdown_device(mem_device); 315 if (result) { 316 /* Set the status of the device to invalid */ 317 mem_device->state = MEMORY_INVALID_STATE; 318 return result; 319 } 320 321 mem_device->state = MEMORY_POWER_OFF_STATE; 322 return result; 323 } 324 325 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 326 { 327 struct acpi_memory_device *mem_device; 328 struct acpi_device *device; 329 330 331 switch (event) { 332 case ACPI_NOTIFY_BUS_CHECK: 333 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 334 "\nReceived BUS CHECK notification for device\n")); 335 /* Fall Through */ 336 case ACPI_NOTIFY_DEVICE_CHECK: 337 if (event == ACPI_NOTIFY_DEVICE_CHECK) 338 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 339 "\nReceived DEVICE CHECK notification for device\n")); 340 if (acpi_memory_get_device(handle, &mem_device)) { 341 printk(KERN_ERR PREFIX "Cannot find driver data\n"); 342 return; 343 } 344 345 if (!acpi_memory_check_device(mem_device)) { 346 if (acpi_memory_enable_device(mem_device)) 347 printk(KERN_ERR PREFIX 348 "Cannot enable memory device\n"); 349 } 350 break; 351 case ACPI_NOTIFY_EJECT_REQUEST: 352 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 353 "\nReceived EJECT REQUEST notification for device\n")); 354 355 if (acpi_bus_get_device(handle, &device)) { 356 printk(KERN_ERR PREFIX "Device doesn't exist\n"); 357 break; 358 } 359 mem_device = acpi_driver_data(device); 360 if (!mem_device) { 361 printk(KERN_ERR PREFIX "Driver Data is NULL\n"); 362 break; 363 } 364 365 /* 366 * Currently disabling memory device from kernel mode 367 * TBD: Can also be disabled from user mode scripts 368 * TBD: Can also be disabled by Callback registration 369 * with generic sysfs driver 370 */ 371 if (acpi_memory_disable_device(mem_device)) 372 printk(KERN_ERR PREFIX 373 "Disable memory device\n"); 374 /* 375 * TBD: Invoke acpi_bus_remove to cleanup data structures 376 */ 377 break; 378 default: 379 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 380 "Unsupported event [0x%x]\n", event)); 381 break; 382 } 383 384 return; 385 } 386 387 static int acpi_memory_device_add(struct acpi_device *device) 388 { 389 int result; 390 struct acpi_memory_device *mem_device = NULL; 391 392 393 if (!device) 394 return -EINVAL; 395 396 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); 397 if (!mem_device) 398 return -ENOMEM; 399 400 INIT_LIST_HEAD(&mem_device->res_list); 401 mem_device->device = device; 402 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME); 403 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS); 404 device->driver_data = mem_device; 405 406 /* Get the range from the _CRS */ 407 result = acpi_memory_get_device_resources(mem_device); 408 if (result) { 409 kfree(mem_device); 410 return result; 411 } 412 413 /* Set the device state */ 414 mem_device->state = MEMORY_POWER_ON_STATE; 415 416 printk(KERN_DEBUG "%s \n", acpi_device_name(device)); 417 418 return result; 419 } 420 421 static int acpi_memory_device_remove(struct acpi_device *device, int type) 422 { 423 struct acpi_memory_device *mem_device = NULL; 424 425 426 if (!device || !acpi_driver_data(device)) 427 return -EINVAL; 428 429 mem_device = acpi_driver_data(device); 430 kfree(mem_device); 431 432 return 0; 433 } 434 435 static int acpi_memory_device_start (struct acpi_device *device) 436 { 437 struct acpi_memory_device *mem_device; 438 int result = 0; 439 440 /* 441 * Early boot code has recognized memory area by EFI/E820. 442 * If DSDT shows these memory devices on boot, hotplug is not necessary 443 * for them. So, it just returns until completion of this driver's 444 * start up. 445 */ 446 if (!acpi_hotmem_initialized) 447 return 0; 448 449 mem_device = acpi_driver_data(device); 450 451 if (!acpi_memory_check_device(mem_device)) { 452 /* call add_memory func */ 453 result = acpi_memory_enable_device(mem_device); 454 if (result) 455 printk(KERN_ERR PREFIX 456 "Error in acpi_memory_enable_device\n"); 457 } 458 return result; 459 } 460 461 /* 462 * Helper function to check for memory device 463 */ 464 static acpi_status is_memory_device(acpi_handle handle) 465 { 466 char *hardware_id; 467 acpi_status status; 468 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 469 struct acpi_device_info *info; 470 471 472 status = acpi_get_object_info(handle, &buffer); 473 if (ACPI_FAILURE(status)) 474 return status; 475 476 info = buffer.pointer; 477 if (!(info->valid & ACPI_VALID_HID)) { 478 kfree(buffer.pointer); 479 return AE_ERROR; 480 } 481 482 hardware_id = info->hardware_id.value; 483 if ((hardware_id == NULL) || 484 (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID))) 485 status = AE_ERROR; 486 487 kfree(buffer.pointer); 488 return status; 489 } 490 491 static acpi_status 492 acpi_memory_register_notify_handler(acpi_handle handle, 493 u32 level, void *ctxt, void **retv) 494 { 495 acpi_status status; 496 497 498 status = is_memory_device(handle); 499 if (ACPI_FAILURE(status)) 500 return AE_OK; /* continue */ 501 502 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, 503 acpi_memory_device_notify, NULL); 504 /* continue */ 505 return AE_OK; 506 } 507 508 static acpi_status 509 acpi_memory_deregister_notify_handler(acpi_handle handle, 510 u32 level, void *ctxt, void **retv) 511 { 512 acpi_status status; 513 514 515 status = is_memory_device(handle); 516 if (ACPI_FAILURE(status)) 517 return AE_OK; /* continue */ 518 519 status = acpi_remove_notify_handler(handle, 520 ACPI_SYSTEM_NOTIFY, 521 acpi_memory_device_notify); 522 523 return AE_OK; /* continue */ 524 } 525 526 static int __init acpi_memory_device_init(void) 527 { 528 int result; 529 acpi_status status; 530 531 532 result = acpi_bus_register_driver(&acpi_memory_device_driver); 533 534 if (result < 0) 535 return -ENODEV; 536 537 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 538 ACPI_UINT32_MAX, 539 acpi_memory_register_notify_handler, 540 NULL, NULL); 541 542 if (ACPI_FAILURE(status)) { 543 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 544 acpi_bus_unregister_driver(&acpi_memory_device_driver); 545 return -ENODEV; 546 } 547 548 acpi_hotmem_initialized = 1; 549 return 0; 550 } 551 552 static void __exit acpi_memory_device_exit(void) 553 { 554 acpi_status status; 555 556 557 /* 558 * Adding this to un-install notification handlers for all the device 559 * handles. 560 */ 561 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 562 ACPI_UINT32_MAX, 563 acpi_memory_deregister_notify_handler, 564 NULL, NULL); 565 566 if (ACPI_FAILURE(status)) 567 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 568 569 acpi_bus_unregister_driver(&acpi_memory_device_driver); 570 571 return; 572 } 573 574 module_init(acpi_memory_device_init); 575 module_exit(acpi_memory_device_exit); 576