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 #undef PREFIX 42 #define PREFIX "ACPI:memory_hp:" 43 44 ACPI_MODULE_NAME("acpi_memhotplug"); 45 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>"); 46 MODULE_DESCRIPTION("Hotplug Mem Driver"); 47 MODULE_LICENSE("GPL"); 48 49 /* Memory Device States */ 50 #define MEMORY_INVALID_STATE 0 51 #define MEMORY_POWER_ON_STATE 1 52 #define MEMORY_POWER_OFF_STATE 2 53 54 static int acpi_memory_device_add(struct acpi_device *device); 55 static int acpi_memory_device_remove(struct acpi_device *device, int type); 56 static int acpi_memory_device_start(struct acpi_device *device); 57 58 static const struct acpi_device_id memory_device_ids[] = { 59 {ACPI_MEMORY_DEVICE_HID, 0}, 60 {"", 0}, 61 }; 62 MODULE_DEVICE_TABLE(acpi, memory_device_ids); 63 64 static struct acpi_driver acpi_memory_device_driver = { 65 .name = "acpi_memhotplug", 66 .class = ACPI_MEMORY_DEVICE_CLASS, 67 .ids = memory_device_ids, 68 .ops = { 69 .add = acpi_memory_device_add, 70 .remove = acpi_memory_device_remove, 71 .start = acpi_memory_device_start, 72 }, 73 }; 74 75 struct acpi_memory_info { 76 struct list_head list; 77 u64 start_addr; /* Memory Range start physical addr */ 78 u64 length; /* Memory Range length */ 79 unsigned short caching; /* memory cache attribute */ 80 unsigned short write_protect; /* memory read/write attribute */ 81 unsigned int enabled:1; 82 }; 83 84 struct acpi_memory_device { 85 struct acpi_device * device; 86 unsigned int state; /* State of the memory device */ 87 struct list_head res_list; 88 }; 89 90 static int acpi_hotmem_initialized; 91 92 static acpi_status 93 acpi_memory_get_resource(struct acpi_resource *resource, void *context) 94 { 95 struct acpi_memory_device *mem_device = context; 96 struct acpi_resource_address64 address64; 97 struct acpi_memory_info *info, *new; 98 acpi_status status; 99 100 status = acpi_resource_to_address64(resource, &address64); 101 if (ACPI_FAILURE(status) || 102 (address64.resource_type != ACPI_MEMORY_RANGE)) 103 return AE_OK; 104 105 list_for_each_entry(info, &mem_device->res_list, list) { 106 /* Can we combine the resource range information? */ 107 if ((info->caching == address64.info.mem.caching) && 108 (info->write_protect == address64.info.mem.write_protect) && 109 (info->start_addr + info->length == address64.minimum)) { 110 info->length += address64.address_length; 111 return AE_OK; 112 } 113 } 114 115 new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL); 116 if (!new) 117 return AE_ERROR; 118 119 INIT_LIST_HEAD(&new->list); 120 new->caching = address64.info.mem.caching; 121 new->write_protect = address64.info.mem.write_protect; 122 new->start_addr = address64.minimum; 123 new->length = address64.address_length; 124 list_add_tail(&new->list, &mem_device->res_list); 125 126 return AE_OK; 127 } 128 129 static int 130 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device) 131 { 132 acpi_status status; 133 struct acpi_memory_info *info, *n; 134 135 136 if (!list_empty(&mem_device->res_list)) 137 return 0; 138 139 status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS, 140 acpi_memory_get_resource, mem_device); 141 if (ACPI_FAILURE(status)) { 142 list_for_each_entry_safe(info, n, &mem_device->res_list, list) 143 kfree(info); 144 INIT_LIST_HEAD(&mem_device->res_list); 145 return -EINVAL; 146 } 147 148 return 0; 149 } 150 151 static int 152 acpi_memory_get_device(acpi_handle handle, 153 struct acpi_memory_device **mem_device) 154 { 155 acpi_status status; 156 acpi_handle phandle; 157 struct acpi_device *device = NULL; 158 struct acpi_device *pdevice = NULL; 159 int result; 160 161 162 if (!acpi_bus_get_device(handle, &device) && device) 163 goto end; 164 165 status = acpi_get_parent(handle, &phandle); 166 if (ACPI_FAILURE(status)) { 167 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent")); 168 return -EINVAL; 169 } 170 171 /* Get the parent device */ 172 result = acpi_bus_get_device(phandle, &pdevice); 173 if (result) { 174 printk(KERN_WARNING PREFIX "Cannot get acpi bus device"); 175 return -EINVAL; 176 } 177 178 /* 179 * Now add the notified device. This creates the acpi_device 180 * and invokes .add function 181 */ 182 result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE); 183 if (result) { 184 printk(KERN_WARNING PREFIX "Cannot add acpi bus"); 185 return -EINVAL; 186 } 187 188 end: 189 *mem_device = acpi_driver_data(device); 190 if (!(*mem_device)) { 191 printk(KERN_ERR "\n driver data not found"); 192 return -ENODEV; 193 } 194 195 return 0; 196 } 197 198 static int acpi_memory_check_device(struct acpi_memory_device *mem_device) 199 { 200 unsigned long long current_status; 201 202 /* Get device present/absent information from the _STA */ 203 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA", 204 NULL, ¤t_status))) 205 return -ENODEV; 206 /* 207 * Check for device status. Device should be 208 * present/enabled/functioning. 209 */ 210 if (!((current_status & ACPI_STA_DEVICE_PRESENT) 211 && (current_status & ACPI_STA_DEVICE_ENABLED) 212 && (current_status & ACPI_STA_DEVICE_FUNCTIONING))) 213 return -ENODEV; 214 215 return 0; 216 } 217 218 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) 219 { 220 int result, num_enabled = 0; 221 struct acpi_memory_info *info; 222 int node; 223 224 225 /* Get the range from the _CRS */ 226 result = acpi_memory_get_device_resources(mem_device); 227 if (result) { 228 printk(KERN_ERR PREFIX "get_device_resources failed\n"); 229 mem_device->state = MEMORY_INVALID_STATE; 230 return result; 231 } 232 233 node = acpi_get_node(mem_device->device->handle); 234 /* 235 * Tell the VM there is more memory here... 236 * Note: Assume that this function returns zero on success 237 * We don't have memory-hot-add rollback function,now. 238 * (i.e. memory-hot-remove function) 239 */ 240 list_for_each_entry(info, &mem_device->res_list, list) { 241 if (info->enabled) { /* just sanity check...*/ 242 num_enabled++; 243 continue; 244 } 245 /* 246 * If the memory block size is zero, please ignore it. 247 * Don't try to do the following memory hotplug flowchart. 248 */ 249 if (!info->length) 250 continue; 251 if (node < 0) 252 node = memory_add_physaddr_to_nid(info->start_addr); 253 254 result = add_memory(node, info->start_addr, info->length); 255 if (result) 256 continue; 257 info->enabled = 1; 258 num_enabled++; 259 } 260 if (!num_enabled) { 261 printk(KERN_ERR PREFIX "add_memory failed\n"); 262 mem_device->state = MEMORY_INVALID_STATE; 263 return -EINVAL; 264 } 265 /* 266 * Sometimes the memory device will contain several memory blocks. 267 * When one memory block is hot-added to the system memory, it will 268 * be regarded as a success. 269 * Otherwise if the last memory block can't be hot-added to the system 270 * memory, it will be failure and the memory device can't be bound with 271 * driver. 272 */ 273 return 0; 274 } 275 276 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device) 277 { 278 acpi_status status; 279 struct acpi_object_list arg_list; 280 union acpi_object arg; 281 unsigned long long current_status; 282 283 284 /* Issue the _EJ0 command */ 285 arg_list.count = 1; 286 arg_list.pointer = &arg; 287 arg.type = ACPI_TYPE_INTEGER; 288 arg.integer.value = 1; 289 status = acpi_evaluate_object(mem_device->device->handle, 290 "_EJ0", &arg_list, NULL); 291 /* Return on _EJ0 failure */ 292 if (ACPI_FAILURE(status)) { 293 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed")); 294 return -ENODEV; 295 } 296 297 /* Evalute _STA to check if the device is disabled */ 298 status = acpi_evaluate_integer(mem_device->device->handle, "_STA", 299 NULL, ¤t_status); 300 if (ACPI_FAILURE(status)) 301 return -ENODEV; 302 303 /* Check for device status. Device should be disabled */ 304 if (current_status & ACPI_STA_DEVICE_ENABLED) 305 return -EINVAL; 306 307 return 0; 308 } 309 310 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) 311 { 312 int result; 313 struct acpi_memory_info *info, *n; 314 315 316 /* 317 * Ask the VM to offline this memory range. 318 * Note: Assume that this function returns zero on success 319 */ 320 list_for_each_entry_safe(info, n, &mem_device->res_list, list) { 321 if (info->enabled) { 322 result = remove_memory(info->start_addr, info->length); 323 if (result) 324 return result; 325 } 326 kfree(info); 327 } 328 329 /* Power-off and eject the device */ 330 result = acpi_memory_powerdown_device(mem_device); 331 if (result) { 332 /* Set the status of the device to invalid */ 333 mem_device->state = MEMORY_INVALID_STATE; 334 return result; 335 } 336 337 mem_device->state = MEMORY_POWER_OFF_STATE; 338 return result; 339 } 340 341 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 342 { 343 struct acpi_memory_device *mem_device; 344 struct acpi_device *device; 345 346 347 switch (event) { 348 case ACPI_NOTIFY_BUS_CHECK: 349 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 350 "\nReceived BUS CHECK notification for device\n")); 351 /* Fall Through */ 352 case ACPI_NOTIFY_DEVICE_CHECK: 353 if (event == ACPI_NOTIFY_DEVICE_CHECK) 354 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 355 "\nReceived DEVICE CHECK notification for device\n")); 356 if (acpi_memory_get_device(handle, &mem_device)) { 357 printk(KERN_ERR PREFIX "Cannot find driver data\n"); 358 return; 359 } 360 361 if (!acpi_memory_check_device(mem_device)) { 362 if (acpi_memory_enable_device(mem_device)) 363 printk(KERN_ERR PREFIX 364 "Cannot enable memory device\n"); 365 } 366 break; 367 case ACPI_NOTIFY_EJECT_REQUEST: 368 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 369 "\nReceived EJECT REQUEST notification for device\n")); 370 371 if (acpi_bus_get_device(handle, &device)) { 372 printk(KERN_ERR PREFIX "Device doesn't exist\n"); 373 break; 374 } 375 mem_device = acpi_driver_data(device); 376 if (!mem_device) { 377 printk(KERN_ERR PREFIX "Driver Data is NULL\n"); 378 break; 379 } 380 381 /* 382 * Currently disabling memory device from kernel mode 383 * TBD: Can also be disabled from user mode scripts 384 * TBD: Can also be disabled by Callback registration 385 * with generic sysfs driver 386 */ 387 if (acpi_memory_disable_device(mem_device)) 388 printk(KERN_ERR PREFIX 389 "Disable memory device\n"); 390 /* 391 * TBD: Invoke acpi_bus_remove to cleanup data structures 392 */ 393 break; 394 default: 395 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 396 "Unsupported event [0x%x]\n", event)); 397 break; 398 } 399 400 return; 401 } 402 403 static int acpi_memory_device_add(struct acpi_device *device) 404 { 405 int result; 406 struct acpi_memory_device *mem_device = NULL; 407 408 409 if (!device) 410 return -EINVAL; 411 412 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); 413 if (!mem_device) 414 return -ENOMEM; 415 416 INIT_LIST_HEAD(&mem_device->res_list); 417 mem_device->device = device; 418 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME); 419 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS); 420 device->driver_data = mem_device; 421 422 /* Get the range from the _CRS */ 423 result = acpi_memory_get_device_resources(mem_device); 424 if (result) { 425 kfree(mem_device); 426 return result; 427 } 428 429 /* Set the device state */ 430 mem_device->state = MEMORY_POWER_ON_STATE; 431 432 printk(KERN_DEBUG "%s \n", acpi_device_name(device)); 433 434 return result; 435 } 436 437 static int acpi_memory_device_remove(struct acpi_device *device, int type) 438 { 439 struct acpi_memory_device *mem_device = NULL; 440 441 442 if (!device || !acpi_driver_data(device)) 443 return -EINVAL; 444 445 mem_device = acpi_driver_data(device); 446 kfree(mem_device); 447 448 return 0; 449 } 450 451 static int acpi_memory_device_start (struct acpi_device *device) 452 { 453 struct acpi_memory_device *mem_device; 454 int result = 0; 455 456 /* 457 * Early boot code has recognized memory area by EFI/E820. 458 * If DSDT shows these memory devices on boot, hotplug is not necessary 459 * for them. So, it just returns until completion of this driver's 460 * start up. 461 */ 462 if (!acpi_hotmem_initialized) 463 return 0; 464 465 mem_device = acpi_driver_data(device); 466 467 if (!acpi_memory_check_device(mem_device)) { 468 /* call add_memory func */ 469 result = acpi_memory_enable_device(mem_device); 470 if (result) 471 printk(KERN_ERR PREFIX 472 "Error in acpi_memory_enable_device\n"); 473 } 474 return result; 475 } 476 477 /* 478 * Helper function to check for memory device 479 */ 480 static acpi_status is_memory_device(acpi_handle handle) 481 { 482 char *hardware_id; 483 acpi_status status; 484 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 485 struct acpi_device_info *info; 486 487 488 status = acpi_get_object_info(handle, &buffer); 489 if (ACPI_FAILURE(status)) 490 return status; 491 492 info = buffer.pointer; 493 if (!(info->valid & ACPI_VALID_HID)) { 494 kfree(buffer.pointer); 495 return AE_ERROR; 496 } 497 498 hardware_id = info->hardware_id.value; 499 if ((hardware_id == NULL) || 500 (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID))) 501 status = AE_ERROR; 502 503 kfree(buffer.pointer); 504 return status; 505 } 506 507 static acpi_status 508 acpi_memory_register_notify_handler(acpi_handle handle, 509 u32 level, void *ctxt, void **retv) 510 { 511 acpi_status status; 512 513 514 status = is_memory_device(handle); 515 if (ACPI_FAILURE(status)) 516 return AE_OK; /* continue */ 517 518 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, 519 acpi_memory_device_notify, NULL); 520 /* continue */ 521 return AE_OK; 522 } 523 524 static acpi_status 525 acpi_memory_deregister_notify_handler(acpi_handle handle, 526 u32 level, void *ctxt, void **retv) 527 { 528 acpi_status status; 529 530 531 status = is_memory_device(handle); 532 if (ACPI_FAILURE(status)) 533 return AE_OK; /* continue */ 534 535 status = acpi_remove_notify_handler(handle, 536 ACPI_SYSTEM_NOTIFY, 537 acpi_memory_device_notify); 538 539 return AE_OK; /* continue */ 540 } 541 542 static int __init acpi_memory_device_init(void) 543 { 544 int result; 545 acpi_status status; 546 547 548 result = acpi_bus_register_driver(&acpi_memory_device_driver); 549 550 if (result < 0) 551 return -ENODEV; 552 553 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 554 ACPI_UINT32_MAX, 555 acpi_memory_register_notify_handler, 556 NULL, NULL); 557 558 if (ACPI_FAILURE(status)) { 559 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 560 acpi_bus_unregister_driver(&acpi_memory_device_driver); 561 return -ENODEV; 562 } 563 564 acpi_hotmem_initialized = 1; 565 return 0; 566 } 567 568 static void __exit acpi_memory_device_exit(void) 569 { 570 acpi_status status; 571 572 573 /* 574 * Adding this to un-install notification handlers for all the device 575 * handles. 576 */ 577 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 578 ACPI_UINT32_MAX, 579 acpi_memory_deregister_notify_handler, 580 NULL, NULL); 581 582 if (ACPI_FAILURE(status)) 583 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 584 585 acpi_bus_unregister_driver(&acpi_memory_device_driver); 586 587 return; 588 } 589 590 module_init(acpi_memory_device_init); 591 module_exit(acpi_memory_device_exit); 592