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 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, &current_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, &current_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);