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