drivers/acpi/acpi_memhotplug.c

   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, &current_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, &current_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);