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 <linux/slab.h> 34#include <acpi/acpi_drivers.h> 35 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#undef PREFIX 43#define PREFIX "ACPI:memory_hp:" 44 45ACPI_MODULE_NAME("acpi_memhotplug"); 46MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>"); 47MODULE_DESCRIPTION("Hotplug Mem Driver"); 48MODULE_LICENSE("GPL"); 49 50/* Memory Device States */ 51#define MEMORY_INVALID_STATE 0 52#define MEMORY_POWER_ON_STATE 1 53#define MEMORY_POWER_OFF_STATE 2 54 55static int acpi_memory_device_add(struct acpi_device *device); 56static int acpi_memory_device_remove(struct acpi_device *device, int type); 57 58static const struct acpi_device_id memory_device_ids[] = { 59 {ACPI_MEMORY_DEVICE_HID, 0}, 60 {"", 0}, 61}; 62MODULE_DEVICE_TABLE(acpi, memory_device_ids); 63 64static 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 }, 72}; 73 74struct acpi_memory_info { 75 struct list_head list; 76 u64 start_addr; /* Memory Range start physical addr */ 77 u64 length; /* Memory Range length */ 78 unsigned short caching; /* memory cache attribute */ 79 unsigned short write_protect; /* memory read/write attribute */ 80 unsigned int enabled:1; 81}; 82 83struct acpi_memory_device { 84 struct acpi_device * device; 85 unsigned int state; /* State of the memory device */ 86 struct list_head res_list; 87}; 88 89static int acpi_hotmem_initialized; 90 91static acpi_status 92acpi_memory_get_resource(struct acpi_resource *resource, void *context) 93{ 94 struct acpi_memory_device *mem_device = context; 95 struct acpi_resource_address64 address64; 96 struct acpi_memory_info *info, *new; 97 acpi_status status; 98 99 status = acpi_resource_to_address64(resource, &address64); 100 if (ACPI_FAILURE(status) || 101 (address64.resource_type != ACPI_MEMORY_RANGE)) 102 return AE_OK; 103 104 list_for_each_entry(info, &mem_device->res_list, list) { 105 /* Can we combine the resource range information? */ 106 if ((info->caching == address64.info.mem.caching) && 107 (info->write_protect == address64.info.mem.write_protect) && 108 (info->start_addr + info->length == address64.minimum)) { 109 info->length += address64.address_length; 110 return AE_OK; 111 } 112 } 113 114 new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL); 115 if (!new) 116 return AE_ERROR; 117 118 INIT_LIST_HEAD(&new->list); 119 new->caching = address64.info.mem.caching; 120 new->write_protect = address64.info.mem.write_protect; 121 new->start_addr = address64.minimum; 122 new->length = address64.address_length; 123 list_add_tail(&new->list, &mem_device->res_list); 124 125 return AE_OK; 126} 127 128static int 129acpi_memory_get_device_resources(struct acpi_memory_device *mem_device) 130{ 131 acpi_status status; 132 struct acpi_memory_info *info, *n; 133 134 135 if (!list_empty(&mem_device->res_list)) 136 return 0; 137 138 status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS, 139 acpi_memory_get_resource, mem_device); 140 if (ACPI_FAILURE(status)) { 141 list_for_each_entry_safe(info, n, &mem_device->res_list, list) 142 kfree(info); 143 INIT_LIST_HEAD(&mem_device->res_list); 144 return -EINVAL; 145 } 146 147 return 0; 148} 149 150static int 151acpi_memory_get_device(acpi_handle handle, 152 struct acpi_memory_device **mem_device) 153{ 154 acpi_status status; 155 acpi_handle phandle; 156 struct acpi_device *device = NULL; 157 struct acpi_device *pdevice = NULL; 158 int result; 159 160 161 if (!acpi_bus_get_device(handle, &device) && device) 162 goto end; 163 164 status = acpi_get_parent(handle, &phandle); 165 if (ACPI_FAILURE(status)) { 166 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent")); 167 return -EINVAL; 168 } 169 170 /* Get the parent device */ 171 result = acpi_bus_get_device(phandle, &pdevice); 172 if (result) { 173 printk(KERN_WARNING PREFIX "Cannot get acpi bus device"); 174 return -EINVAL; 175 } 176 177 /* 178 * Now add the notified device. This creates the acpi_device 179 * and invokes .add function 180 */ 181 result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE); 182 if (result) { 183 printk(KERN_WARNING PREFIX "Cannot add acpi bus"); 184 return -EINVAL; 185 } 186 187 end: 188 *mem_device = acpi_driver_data(device); 189 if (!(*mem_device)) { 190 printk(KERN_ERR "\n driver data not found"); 191 return -ENODEV; 192 } 193 194 return 0; 195} 196 197static int acpi_memory_check_device(struct acpi_memory_device *mem_device) 198{ 199 unsigned long long current_status; 200 201 /* Get device present/absent information from the _STA */ 202 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA", 203 NULL, ¤t_status))) 204 return -ENODEV; 205 /* 206 * Check for device status. Device should be 207 * present/enabled/functioning. 208 */ 209 if (!((current_status & ACPI_STA_DEVICE_PRESENT) 210 && (current_status & ACPI_STA_DEVICE_ENABLED) 211 && (current_status & ACPI_STA_DEVICE_FUNCTIONING))) 212 return -ENODEV; 213 214 return 0; 215} 216 217static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) 218{ 219 int result, num_enabled = 0; 220 struct acpi_memory_info *info; 221 int node; 222 223 224 /* Get the range from the _CRS */ 225 result = acpi_memory_get_device_resources(mem_device); 226 if (result) { 227 printk(KERN_ERR PREFIX "get_device_resources failed\n"); 228 mem_device->state = MEMORY_INVALID_STATE; 229 return result; 230 } 231 232 node = acpi_get_node(mem_device->device->handle); 233 /* 234 * Tell the VM there is more memory here... 235 * Note: Assume that this function returns zero on success 236 * We don't have memory-hot-add rollback function,now. 237 * (i.e. memory-hot-remove function) 238 */ 239 list_for_each_entry(info, &mem_device->res_list, list) { 240 if (info->enabled) { /* just sanity check...*/ 241 num_enabled++; 242 continue; 243 } 244 /* 245 * If the memory block size is zero, please ignore it. 246 * Don't try to do the following memory hotplug flowchart. 247 */ 248 if (!info->length) 249 continue; 250 if (node < 0) 251 node = memory_add_physaddr_to_nid(info->start_addr); 252 253 result = add_memory(node, info->start_addr, info->length); 254 if (result) 255 continue; 256 info->enabled = 1; 257 num_enabled++; 258 } 259 if (!num_enabled) { 260 printk(KERN_ERR PREFIX "add_memory failed\n"); 261 mem_device->state = MEMORY_INVALID_STATE; 262 return -EINVAL; 263 } 264 /* 265 * Sometimes the memory device will contain several memory blocks. 266 * When one memory block is hot-added to the system memory, it will 267 * be regarded as a success. 268 * Otherwise if the last memory block can't be hot-added to the system 269 * memory, it will be failure and the memory device can't be bound with 270 * driver. 271 */ 272 return 0; 273} 274 275static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device) 276{ 277 acpi_status status; 278 struct acpi_object_list arg_list; 279 union acpi_object arg; 280 unsigned long long current_status; 281 282 283 /* Issue the _EJ0 command */ 284 arg_list.count = 1; 285 arg_list.pointer = &arg; 286 arg.type = ACPI_TYPE_INTEGER; 287 arg.integer.value = 1; 288 status = acpi_evaluate_object(mem_device->device->handle, 289 "_EJ0", &arg_list, NULL); 290 /* Return on _EJ0 failure */ 291 if (ACPI_FAILURE(status)) { 292 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed")); 293 return -ENODEV; 294 } 295 296 /* Evalute _STA to check if the device is disabled */ 297 status = acpi_evaluate_integer(mem_device->device->handle, "_STA", 298 NULL, ¤t_status); 299 if (ACPI_FAILURE(status)) 300 return -ENODEV; 301 302 /* Check for device status. Device should be disabled */ 303 if (current_status & ACPI_STA_DEVICE_ENABLED) 304 return -EINVAL; 305 306 return 0; 307} 308 309static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) 310{ 311 int result; 312 struct acpi_memory_info *info, *n; 313 314 315 /* 316 * Ask the VM to offline this memory range. 317 * Note: Assume that this function returns zero on success 318 */ 319 list_for_each_entry_safe(info, n, &mem_device->res_list, list) { 320 if (info->enabled) { 321 result = remove_memory(info->start_addr, info->length); 322 if (result) 323 return result; 324 } 325 kfree(info); 326 } 327 328 /* Power-off and eject the device */ 329 result = acpi_memory_powerdown_device(mem_device); 330 if (result) { 331 /* Set the status of the device to invalid */ 332 mem_device->state = MEMORY_INVALID_STATE; 333 return result; 334 } 335 336 mem_device->state = MEMORY_POWER_OFF_STATE; 337 return result; 338} 339 340static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 341{ 342 struct acpi_memory_device *mem_device; 343 struct acpi_device *device; 344 345 346 switch (event) { 347 case ACPI_NOTIFY_BUS_CHECK: 348 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 349 "\nReceived BUS CHECK notification for device\n")); 350 /* Fall Through */ 351 case ACPI_NOTIFY_DEVICE_CHECK: 352 if (event == ACPI_NOTIFY_DEVICE_CHECK) 353 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 354 "\nReceived DEVICE CHECK notification for device\n")); 355 if (acpi_memory_get_device(handle, &mem_device)) { 356 printk(KERN_ERR PREFIX "Cannot find driver data\n"); 357 return; 358 } 359 360 if (!acpi_memory_check_device(mem_device)) { 361 if (acpi_memory_enable_device(mem_device)) 362 printk(KERN_ERR PREFIX 363 "Cannot enable memory device\n"); 364 } 365 break; 366 case ACPI_NOTIFY_EJECT_REQUEST: 367 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 368 "\nReceived EJECT REQUEST notification for device\n")); 369 370 if (acpi_bus_get_device(handle, &device)) { 371 printk(KERN_ERR PREFIX "Device doesn't exist\n"); 372 break; 373 } 374 mem_device = acpi_driver_data(device); 375 if (!mem_device) { 376 printk(KERN_ERR PREFIX "Driver Data is NULL\n"); 377 break; 378 } 379 380 /* 381 * Currently disabling memory device from kernel mode 382 * TBD: Can also be disabled from user mode scripts 383 * TBD: Can also be disabled by Callback registration 384 * with generic sysfs driver 385 */ 386 if (acpi_memory_disable_device(mem_device)) 387 printk(KERN_ERR PREFIX 388 "Disable memory device\n"); 389 /* 390 * TBD: Invoke acpi_bus_remove to cleanup data structures 391 */ 392 break; 393 default: 394 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 395 "Unsupported event [0x%x]\n", event)); 396 break; 397 } 398 399 return; 400} 401 402static int acpi_memory_device_add(struct acpi_device *device) 403{ 404 int result; 405 struct acpi_memory_device *mem_device = NULL; 406 407 408 if (!device) 409 return -EINVAL; 410 411 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); 412 if (!mem_device) 413 return -ENOMEM; 414 415 INIT_LIST_HEAD(&mem_device->res_list); 416 mem_device->device = device; 417 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME); 418 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS); 419 device->driver_data = mem_device; 420 421 /* Get the range from the _CRS */ 422 result = acpi_memory_get_device_resources(mem_device); 423 if (result) { 424 kfree(mem_device); 425 return result; 426 } 427 428 /* Set the device state */ 429 mem_device->state = MEMORY_POWER_ON_STATE; 430 431 printk(KERN_DEBUG "%s \n", acpi_device_name(device)); 432 433 /* 434 * Early boot code has recognized memory area by EFI/E820. 435 * If DSDT shows these memory devices on boot, hotplug is not necessary 436 * for them. So, it just returns until completion of this driver's 437 * start up. 438 */ 439 if (!acpi_hotmem_initialized) 440 return 0; 441 442 if (!acpi_memory_check_device(mem_device)) { 443 /* call add_memory func */ 444 result = acpi_memory_enable_device(mem_device); 445 if (result) 446 printk(KERN_ERR PREFIX 447 "Error in acpi_memory_enable_device\n"); 448 } 449 return result; 450} 451 452static int acpi_memory_device_remove(struct acpi_device *device, int type) 453{ 454 struct acpi_memory_device *mem_device = NULL; 455 456 457 if (!device || !acpi_driver_data(device)) 458 return -EINVAL; 459 460 mem_device = acpi_driver_data(device); 461 kfree(mem_device); 462 463 return 0; 464} 465 466/* 467 * Helper function to check for memory device 468 */ 469static acpi_status is_memory_device(acpi_handle handle) 470{ 471 char *hardware_id; 472 acpi_status status; 473 struct acpi_device_info *info; 474 475 status = acpi_get_object_info(handle, &info); 476 if (ACPI_FAILURE(status)) 477 return status; 478 479 if (!(info->valid & ACPI_VALID_HID)) { 480 kfree(info); 481 return AE_ERROR; 482 } 483 484 hardware_id = info->hardware_id.string; 485 if ((hardware_id == NULL) || 486 (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID))) 487 status = AE_ERROR; 488 489 kfree(info); 490 return status; 491} 492 493static acpi_status 494acpi_memory_register_notify_handler(acpi_handle handle, 495 u32 level, void *ctxt, void **retv) 496{ 497 acpi_status status; 498 499 500 status = is_memory_device(handle); 501 if (ACPI_FAILURE(status)) 502 return AE_OK; /* continue */ 503 504 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, 505 acpi_memory_device_notify, NULL); 506 /* continue */ 507 return AE_OK; 508} 509 510static acpi_status 511acpi_memory_deregister_notify_handler(acpi_handle handle, 512 u32 level, void *ctxt, void **retv) 513{ 514 acpi_status status; 515 516 517 status = is_memory_device(handle); 518 if (ACPI_FAILURE(status)) 519 return AE_OK; /* continue */ 520 521 status = acpi_remove_notify_handler(handle, 522 ACPI_SYSTEM_NOTIFY, 523 acpi_memory_device_notify); 524 525 return AE_OK; /* continue */ 526} 527 528static int __init acpi_memory_device_init(void) 529{ 530 int result; 531 acpi_status status; 532 533 534 result = acpi_bus_register_driver(&acpi_memory_device_driver); 535 536 if (result < 0) 537 return -ENODEV; 538 539 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 540 ACPI_UINT32_MAX, 541 acpi_memory_register_notify_handler, NULL, 542 NULL, NULL); 543 544 if (ACPI_FAILURE(status)) { 545 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 546 acpi_bus_unregister_driver(&acpi_memory_device_driver); 547 return -ENODEV; 548 } 549 550 acpi_hotmem_initialized = 1; 551 return 0; 552} 553 554static void __exit acpi_memory_device_exit(void) 555{ 556 acpi_status status; 557 558 559 /* 560 * Adding this to un-install notification handlers for all the device 561 * handles. 562 */ 563 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 564 ACPI_UINT32_MAX, 565 acpi_memory_deregister_notify_handler, NULL, 566 NULL, NULL); 567 568 if (ACPI_FAILURE(status)) 569 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 570 571 acpi_bus_unregister_driver(&acpi_memory_device_driver); 572 573 return; 574} 575 576module_init(acpi_memory_device_init); 577module_exit(acpi_memory_device_exit); 578