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 firmare 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_COMPONENT 0x08000000UL 36 #define ACPI_MEMORY_DEVICE_CLASS "memory" 37 #define ACPI_MEMORY_DEVICE_HID "PNP0C80" 38 #define ACPI_MEMORY_DEVICE_NAME "Hotplug Mem Device" 39 40 #define _COMPONENT ACPI_MEMORY_DEVICE_COMPONENT 41 42 ACPI_MODULE_NAME("acpi_memhotplug"); 43 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>"); 44 MODULE_DESCRIPTION("Hotplug Mem Driver"); 45 MODULE_LICENSE("GPL"); 46 47 /* ACPI _STA method values */ 48 #define ACPI_MEMORY_STA_PRESENT (0x00000001UL) 49 #define ACPI_MEMORY_STA_ENABLED (0x00000002UL) 50 #define ACPI_MEMORY_STA_FUNCTIONAL (0x00000008UL) 51 52 /* Memory Device States */ 53 #define MEMORY_INVALID_STATE 0 54 #define MEMORY_POWER_ON_STATE 1 55 #define MEMORY_POWER_OFF_STATE 2 56 57 static int acpi_memory_device_add(struct acpi_device *device); 58 static int acpi_memory_device_remove(struct acpi_device *device, int type); 59 static int acpi_memory_device_start(struct acpi_device *device); 60 61 static struct acpi_driver acpi_memory_device_driver = { 62 .name = "acpi_memhotplug", 63 .class = ACPI_MEMORY_DEVICE_CLASS, 64 .ids = ACPI_MEMORY_DEVICE_HID, 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 current_status; 197 198 199 /* Get device present/absent information from the _STA */ 200 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA", 201 NULL, ¤t_status))) 202 return -ENODEV; 203 /* 204 * Check for device status. Device should be 205 * present/enabled/functioning. 206 */ 207 if (!((current_status & ACPI_MEMORY_STA_PRESENT) 208 && (current_status & ACPI_MEMORY_STA_ENABLED) 209 && (current_status & ACPI_MEMORY_STA_FUNCTIONAL))) 210 return -ENODEV; 211 212 return 0; 213 } 214 215 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) 216 { 217 int result, num_enabled = 0; 218 struct acpi_memory_info *info; 219 int node; 220 221 222 /* Get the range from the _CRS */ 223 result = acpi_memory_get_device_resources(mem_device); 224 if (result) { 225 printk(KERN_ERR PREFIX "get_device_resources failed\n"); 226 mem_device->state = MEMORY_INVALID_STATE; 227 return result; 228 } 229 230 node = acpi_get_node(mem_device->device->handle); 231 /* 232 * Tell the VM there is more memory here... 233 * Note: Assume that this function returns zero on success 234 * We don't have memory-hot-add rollback function,now. 235 * (i.e. memory-hot-remove function) 236 */ 237 list_for_each_entry(info, &mem_device->res_list, list) { 238 if (info->enabled) { /* just sanity check...*/ 239 num_enabled++; 240 continue; 241 } 242 243 if (node < 0) 244 node = memory_add_physaddr_to_nid(info->start_addr); 245 246 result = add_memory(node, info->start_addr, info->length); 247 if (result) 248 continue; 249 info->enabled = 1; 250 num_enabled++; 251 } 252 if (!num_enabled) { 253 printk(KERN_ERR PREFIX "add_memory failed\n"); 254 mem_device->state = MEMORY_INVALID_STATE; 255 return -EINVAL; 256 } 257 258 return result; 259 } 260 261 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device) 262 { 263 acpi_status status; 264 struct acpi_object_list arg_list; 265 union acpi_object arg; 266 unsigned long current_status; 267 268 269 /* Issue the _EJ0 command */ 270 arg_list.count = 1; 271 arg_list.pointer = &arg; 272 arg.type = ACPI_TYPE_INTEGER; 273 arg.integer.value = 1; 274 status = acpi_evaluate_object(mem_device->device->handle, 275 "_EJ0", &arg_list, NULL); 276 /* Return on _EJ0 failure */ 277 if (ACPI_FAILURE(status)) { 278 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed")); 279 return -ENODEV; 280 } 281 282 /* Evalute _STA to check if the device is disabled */ 283 status = acpi_evaluate_integer(mem_device->device->handle, "_STA", 284 NULL, ¤t_status); 285 if (ACPI_FAILURE(status)) 286 return -ENODEV; 287 288 /* Check for device status. Device should be disabled */ 289 if (current_status & ACPI_MEMORY_STA_ENABLED) 290 return -EINVAL; 291 292 return 0; 293 } 294 295 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) 296 { 297 int result; 298 struct acpi_memory_info *info, *n; 299 300 301 /* 302 * Ask the VM to offline this memory range. 303 * Note: Assume that this function returns zero on success 304 */ 305 list_for_each_entry_safe(info, n, &mem_device->res_list, list) { 306 if (info->enabled) { 307 result = remove_memory(info->start_addr, info->length); 308 if (result) 309 return result; 310 } 311 kfree(info); 312 } 313 314 /* Power-off and eject the device */ 315 result = acpi_memory_powerdown_device(mem_device); 316 if (result) { 317 /* Set the status of the device to invalid */ 318 mem_device->state = MEMORY_INVALID_STATE; 319 return result; 320 } 321 322 mem_device->state = MEMORY_POWER_OFF_STATE; 323 return result; 324 } 325 326 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 327 { 328 struct acpi_memory_device *mem_device; 329 struct acpi_device *device; 330 331 332 switch (event) { 333 case ACPI_NOTIFY_BUS_CHECK: 334 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 335 "\nReceived BUS CHECK notification for device\n")); 336 /* Fall Through */ 337 case ACPI_NOTIFY_DEVICE_CHECK: 338 if (event == ACPI_NOTIFY_DEVICE_CHECK) 339 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 340 "\nReceived DEVICE CHECK notification for device\n")); 341 if (acpi_memory_get_device(handle, &mem_device)) { 342 printk(KERN_ERR PREFIX "Cannot find driver data\n"); 343 return; 344 } 345 346 if (!acpi_memory_check_device(mem_device)) { 347 if (acpi_memory_enable_device(mem_device)) 348 printk(KERN_ERR PREFIX 349 "Cannot enable memory device\n"); 350 } 351 break; 352 case ACPI_NOTIFY_EJECT_REQUEST: 353 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 354 "\nReceived EJECT REQUEST notification for device\n")); 355 356 if (acpi_bus_get_device(handle, &device)) { 357 printk(KERN_ERR PREFIX "Device doesn't exist\n"); 358 break; 359 } 360 mem_device = acpi_driver_data(device); 361 if (!mem_device) { 362 printk(KERN_ERR PREFIX "Driver Data is NULL\n"); 363 break; 364 } 365 366 /* 367 * Currently disabling memory device from kernel mode 368 * TBD: Can also be disabled from user mode scripts 369 * TBD: Can also be disabled by Callback registration 370 * with generic sysfs driver 371 */ 372 if (acpi_memory_disable_device(mem_device)) 373 printk(KERN_ERR PREFIX 374 "Disable memory device\n"); 375 /* 376 * TBD: Invoke acpi_bus_remove to cleanup data structures 377 */ 378 break; 379 default: 380 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 381 "Unsupported event [0x%x]\n", event)); 382 break; 383 } 384 385 return; 386 } 387 388 static int acpi_memory_device_add(struct acpi_device *device) 389 { 390 int result; 391 struct acpi_memory_device *mem_device = NULL; 392 393 394 if (!device) 395 return -EINVAL; 396 397 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); 398 if (!mem_device) 399 return -ENOMEM; 400 401 INIT_LIST_HEAD(&mem_device->res_list); 402 mem_device->device = device; 403 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME); 404 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS); 405 acpi_driver_data(device) = mem_device; 406 407 /* Get the range from the _CRS */ 408 result = acpi_memory_get_device_resources(mem_device); 409 if (result) { 410 kfree(mem_device); 411 return result; 412 } 413 414 /* Set the device state */ 415 mem_device->state = MEMORY_POWER_ON_STATE; 416 417 printk(KERN_DEBUG "%s \n", acpi_device_name(device)); 418 419 return result; 420 } 421 422 static int acpi_memory_device_remove(struct acpi_device *device, int type) 423 { 424 struct acpi_memory_device *mem_device = NULL; 425 426 427 if (!device || !acpi_driver_data(device)) 428 return -EINVAL; 429 430 mem_device = acpi_driver_data(device); 431 kfree(mem_device); 432 433 return 0; 434 } 435 436 static int acpi_memory_device_start (struct acpi_device *device) 437 { 438 struct acpi_memory_device *mem_device; 439 int result = 0; 440 441 /* 442 * Early boot code has recognized memory area by EFI/E820. 443 * If DSDT shows these memory devices on boot, hotplug is not necessary 444 * for them. So, it just returns until completion of this driver's 445 * start up. 446 */ 447 if (!acpi_hotmem_initialized) 448 return 0; 449 450 mem_device = acpi_driver_data(device); 451 452 if (!acpi_memory_check_device(mem_device)) { 453 /* call add_memory func */ 454 result = acpi_memory_enable_device(mem_device); 455 if (result) 456 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 457 "Error in acpi_memory_enable_device\n")); 458 } 459 return result; 460 } 461 462 /* 463 * Helper function to check for memory device 464 */ 465 static acpi_status is_memory_device(acpi_handle handle) 466 { 467 char *hardware_id; 468 acpi_status status; 469 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 470 struct acpi_device_info *info; 471 472 473 status = acpi_get_object_info(handle, &buffer); 474 if (ACPI_FAILURE(status)) 475 return status; 476 477 info = buffer.pointer; 478 if (!(info->valid & ACPI_VALID_HID)) { 479 kfree(buffer.pointer); 480 return AE_ERROR; 481 } 482 483 hardware_id = info->hardware_id.value; 484 if ((hardware_id == NULL) || 485 (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID))) 486 status = AE_ERROR; 487 488 kfree(buffer.pointer); 489 return status; 490 } 491 492 static acpi_status 493 acpi_memory_register_notify_handler(acpi_handle handle, 494 u32 level, void *ctxt, void **retv) 495 { 496 acpi_status status; 497 498 499 status = is_memory_device(handle); 500 if (ACPI_FAILURE(status)) 501 return AE_OK; /* continue */ 502 503 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, 504 acpi_memory_device_notify, NULL); 505 /* continue */ 506 return AE_OK; 507 } 508 509 static acpi_status 510 acpi_memory_deregister_notify_handler(acpi_handle handle, 511 u32 level, void *ctxt, void **retv) 512 { 513 acpi_status status; 514 515 516 status = is_memory_device(handle); 517 if (ACPI_FAILURE(status)) 518 return AE_OK; /* continue */ 519 520 status = acpi_remove_notify_handler(handle, 521 ACPI_SYSTEM_NOTIFY, 522 acpi_memory_device_notify); 523 524 return AE_OK; /* continue */ 525 } 526 527 static int __init acpi_memory_device_init(void) 528 { 529 int result; 530 acpi_status status; 531 532 533 result = acpi_bus_register_driver(&acpi_memory_device_driver); 534 535 if (result < 0) 536 return -ENODEV; 537 538 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 539 ACPI_UINT32_MAX, 540 acpi_memory_register_notify_handler, 541 NULL, NULL); 542 543 if (ACPI_FAILURE(status)) { 544 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 545 acpi_bus_unregister_driver(&acpi_memory_device_driver); 546 return -ENODEV; 547 } 548 549 acpi_hotmem_initialized = 1; 550 return 0; 551 } 552 553 static void __exit acpi_memory_device_exit(void) 554 { 555 acpi_status status; 556 557 558 /* 559 * Adding this to un-install notification handlers for all the device 560 * handles. 561 */ 562 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 563 ACPI_UINT32_MAX, 564 acpi_memory_deregister_notify_handler, 565 NULL, NULL); 566 567 if (ACPI_FAILURE(status)) 568 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 569 570 acpi_bus_unregister_driver(&acpi_memory_device_driver); 571 572 return; 573 } 574 575 module_init(acpi_memory_device_init); 576 module_exit(acpi_memory_device_exit); 577