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 <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
  45 ACPI_MODULE_NAME("acpi_memhotplug");
  46 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
  47 MODULE_DESCRIPTION("Hotplug Mem Driver");
  48 MODULE_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
  55 static int acpi_memory_device_add(struct acpi_device *device);
  56 static int acpi_memory_device_remove(struct acpi_device *device, int type);
  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                 },
  72 };
  73
  74 struct 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         unsigned int failed: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 acpi_status
  91 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
  92 {
  93         struct acpi_memory_device *mem_device = context;
  94         struct acpi_resource_address64 address64;
  95         struct acpi_memory_info *info, *new;
  96         acpi_status status;
  97
  98         status = acpi_resource_to_address64(resource, &address64);
  99         if (ACPI_FAILURE(status) ||
 100             (address64.resource_type != ACPI_MEMORY_RANGE))
 101                 return AE_OK;
 102
 103         list_for_each_entry(info, &mem_device->res_list, list) {
 104                 /* Can we combine the resource range information? */
 105                 if ((info->caching == address64.info.mem.caching) &&
 106                     (info->write_protect == address64.info.mem.write_protect) &&
 107                     (info->start_addr + info->length == address64.minimum)) {
 108                         info->length += address64.address_length;
 109                         return AE_OK;
 110                 }
 111         }
 112
 113         new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
 114         if (!new)
 115                 return AE_ERROR;
 116
 117         INIT_LIST_HEAD(&new->list);
 118         new->caching = address64.info.mem.caching;
 119         new->write_protect = address64.info.mem.write_protect;
 120         new->start_addr = address64.minimum;
 121         new->length = address64.address_length;
 122         list_add_tail(&new->list, &mem_device->res_list);
 123
 124         return AE_OK;
 125 }
 126
 127 static void
 128 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
 129 {
 130         struct acpi_memory_info *info, *n;
 131
 132         list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 133                 kfree(info);
 134         INIT_LIST_HEAD(&mem_device->res_list);
 135 }
 136
 137 static int
 138 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 139 {
 140         acpi_status status;
 141
 142         if (!list_empty(&mem_device->res_list))
 143                 return 0;
 144
 145         status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 146                                      acpi_memory_get_resource, mem_device);
 147         if (ACPI_FAILURE(status)) {
 148                 acpi_memory_free_device_resources(mem_device);
 149                 return -EINVAL;
 150         }
 151
 152         return 0;
 153 }
 154
 155 static int
 156 acpi_memory_get_device(acpi_handle handle,
 157                        struct acpi_memory_device **mem_device)
 158 {
 159         acpi_status status;
 160         acpi_handle phandle;
 161         struct acpi_device *device = NULL;
 162         struct acpi_device *pdevice = NULL;
 163         int result;
 164
 165
 166         if (!acpi_bus_get_device(handle, &device) && device)
 167                 goto end;
 168
 169         status = acpi_get_parent(handle, &phandle);
 170         if (ACPI_FAILURE(status)) {
 171                 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
 172                 return -EINVAL;
 173         }
 174
 175         /* Get the parent device */
 176         result = acpi_bus_get_device(phandle, &pdevice);
 177         if (result) {
 178                 printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
 179                 return -EINVAL;
 180         }
 181
 182         /*
 183          * Now add the notified device.  This creates the acpi_device
 184          * and invokes .add function
 185          */
 186         result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
 187         if (result) {
 188                 printk(KERN_WARNING PREFIX "Cannot add acpi bus");
 189                 return -EINVAL;
 190         }
 191
 192       end:
 193         *mem_device = acpi_driver_data(device);
 194         if (!(*mem_device)) {
 195                 printk(KERN_ERR "\n driver data not found");
 196                 return -ENODEV;
 197         }
 198
 199         return 0;
 200 }
 201
 202 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 203 {
 204         unsigned long long current_status;
 205
 206         /* Get device present/absent information from the _STA */
 207         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
 208                                                NULL, &current_status)))
 209                 return -ENODEV;
 210         /*
 211          * Check for device status. Device should be
 212          * present/enabled/functioning.
 213          */
 214         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 215               && (current_status & ACPI_STA_DEVICE_ENABLED)
 216               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 217                 return -ENODEV;
 218
 219         return 0;
 220 }
 221
 222 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 223 {
 224         int result, num_enabled = 0;
 225         struct acpi_memory_info *info;
 226         int node;
 227
 228
 229         /* Get the range from the _CRS */
 230         result = acpi_memory_get_device_resources(mem_device);
 231         if (result) {
 232                 printk(KERN_ERR PREFIX "get_device_resources failed\n");
 233                 mem_device->state = MEMORY_INVALID_STATE;
 234                 return result;
 235         }
 236
 237         node = acpi_get_node(mem_device->device->handle);
 238         /*
 239          * Tell the VM there is more memory here...
 240          * Note: Assume that this function returns zero on success
 241          * We don't have memory-hot-add rollback function,now.
 242          * (i.e. memory-hot-remove function)
 243          */
 244         list_for_each_entry(info, &mem_device->res_list, list) {
 245                 if (info->enabled) { /* just sanity check...*/
 246                         num_enabled++;
 247                         continue;
 248                 }
 249                 /*
 250                  * If the memory block size is zero, please ignore it.
 251                  * Don't try to do the following memory hotplug flowchart.
 252                  */
 253                 if (!info->length)
 254                         continue;
 255                 if (node < 0)
 256                         node = memory_add_physaddr_to_nid(info->start_addr);
 257
 258                 result = add_memory(node, info->start_addr, info->length);
 259
 260                 /*
 261                  * If the memory block has been used by the kernel, add_memory()
 262                  * returns -EEXIST. If add_memory() returns the other error, it
 263                  * means that this memory block is not used by the kernel.
 264                  */
 265                 if (result && result != -EEXIST) {
 266                         info->failed = 1;
 267                         continue;
 268                 }
 269
 270                 if (!result)
 271                         info->enabled = 1;
 272                 /*
 273                  * Add num_enable even if add_memory() returns -EEXIST, so the
 274                  * device is bound to this driver.
 275                  */
 276                 num_enabled++;
 277         }
 278         if (!num_enabled) {
 279                 printk(KERN_ERR PREFIX "add_memory failed\n");
 280                 mem_device->state = MEMORY_INVALID_STATE;
 281                 return -EINVAL;
 282         }
 283         /*
 284          * Sometimes the memory device will contain several memory blocks.
 285          * When one memory block is hot-added to the system memory, it will
 286          * be regarded as a success.
 287          * Otherwise if the last memory block can't be hot-added to the system
 288          * memory, it will be failure and the memory device can't be bound with
 289          * driver.
 290          */
 291         return 0;
 292 }
 293
 294 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 295 {
 296         acpi_status status;
 297         struct acpi_object_list arg_list;
 298         union acpi_object arg;
 299         unsigned long long current_status;
 300
 301
 302         /* Issue the _EJ0 command */
 303         arg_list.count = 1;
 304         arg_list.pointer = &arg;
 305         arg.type = ACPI_TYPE_INTEGER;
 306         arg.integer.value = 1;
 307         status = acpi_evaluate_object(mem_device->device->handle,
 308                                       "_EJ0", &arg_list, NULL);
 309         /* Return on _EJ0 failure */
 310         if (ACPI_FAILURE(status)) {
 311                 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
 312                 return -ENODEV;
 313         }
 314
 315         /* Evalute _STA to check if the device is disabled */
 316         status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
 317                                        NULL, &current_status);
 318         if (ACPI_FAILURE(status))
 319                 return -ENODEV;
 320
 321         /* Check for device status.  Device should be disabled */
 322         if (current_status & ACPI_STA_DEVICE_ENABLED)
 323                 return -EINVAL;
 324
 325         return 0;
 326 }
 327
 328 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 329 {
 330         int result;
 331         struct acpi_memory_info *info, *n;
 332
 333
 334         /*
 335          * Ask the VM to offline this memory range.
 336          * Note: Assume that this function returns zero on success
 337          */
 338         list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 339                 if (info->failed)
 340                         /* The kernel does not use this memory block */
 341                         continue;
 342
 343                 if (!info->enabled)
 344                         /*
 345                          * The kernel uses this memory block, but it may be not
 346                          * managed by us.
 347                          */
 348                         return -EBUSY;
 349
 350                 result = remove_memory(info->start_addr, info->length);
 351                 if (result)
 352                         return result;
 353                 list_del(&info->list);
 354                 kfree(info);
 355         }
 356
 357         /* Power-off and eject the device */
 358         result = acpi_memory_powerdown_device(mem_device);
 359         if (result) {
 360                 /* Set the status of the device to invalid */
 361                 mem_device->state = MEMORY_INVALID_STATE;
 362                 return result;
 363         }
 364
 365         mem_device->state = MEMORY_POWER_OFF_STATE;
 366         return result;
 367 }
 368
 369 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 370 {
 371         struct acpi_memory_device *mem_device;
 372         struct acpi_device *device;
 373         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 374
 375         switch (event) {
 376         case ACPI_NOTIFY_BUS_CHECK:
 377                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 378                                   "\nReceived BUS CHECK notification for device\n"));
 379                 /* Fall Through */
 380         case ACPI_NOTIFY_DEVICE_CHECK:
 381                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
 382                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 383                                           "\nReceived DEVICE CHECK notification for device\n"));
 384                 if (acpi_memory_get_device(handle, &mem_device)) {
 385                         printk(KERN_ERR PREFIX "Cannot find driver data\n");
 386                         break;
 387                 }
 388
 389                 if (acpi_memory_check_device(mem_device))
 390                         break;
 391
 392                 if (acpi_memory_enable_device(mem_device)) {
 393                         printk(KERN_ERR PREFIX "Cannot enable memory device\n");
 394                         break;
 395                 }
 396
 397                 ost_code = ACPI_OST_SC_SUCCESS;
 398                 break;
 399
 400         case ACPI_NOTIFY_EJECT_REQUEST:
 401                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 402                                   "\nReceived EJECT REQUEST notification for device\n"));
 403
 404                 if (acpi_bus_get_device(handle, &device)) {
 405                         printk(KERN_ERR PREFIX "Device doesn't exist\n");
 406                         break;
 407                 }
 408                 mem_device = acpi_driver_data(device);
 409                 if (!mem_device) {
 410                         printk(KERN_ERR PREFIX "Driver Data is NULL\n");
 411                         break;
 412                 }
 413
 414                 /*
 415                  * Currently disabling memory device from kernel mode
 416                  * TBD: Can also be disabled from user mode scripts
 417                  * TBD: Can also be disabled by Callback registration
 418                  *      with generic sysfs driver
 419                  */
 420                 if (acpi_memory_disable_device(mem_device)) {
 421                         printk(KERN_ERR PREFIX "Disable memory device\n");
 422                         /*
 423                          * If _EJ0 was called but failed, _OST is not
 424                          * necessary.
 425                          */
 426                         if (mem_device->state == MEMORY_INVALID_STATE)
 427                                 return;
 428
 429                         break;
 430                 }
 431
 432                 /*
 433                  * TBD: Invoke acpi_bus_remove to cleanup data structures
 434                  */
 435
 436                 /* _EJ0 succeeded; _OST is not necessary */
 437                 return;
 438
 439         default:
 440                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 441                                   "Unsupported event [0x%x]\n", event));
 442
 443                 /* non-hotplug event; possibly handled by other handler */
 444                 return;
 445         }
 446
 447         /* Inform firmware that the hotplug operation has completed */
 448         (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
 449         return;
 450 }
 451
 452 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
 453 {
 454         if (!mem_device)
 455                 return;
 456
 457         acpi_memory_free_device_resources(mem_device);
 458         kfree(mem_device);
 459 }
 460
 461 static int acpi_memory_device_add(struct acpi_device *device)
 462 {
 463         int result;
 464         struct acpi_memory_device *mem_device = NULL;
 465
 466
 467         if (!device)
 468                 return -EINVAL;
 469
 470         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 471         if (!mem_device)
 472                 return -ENOMEM;
 473
 474         INIT_LIST_HEAD(&mem_device->res_list);
 475         mem_device->device = device;
 476         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 477         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 478         device->driver_data = mem_device;
 479
 480         /* Get the range from the _CRS */
 481         result = acpi_memory_get_device_resources(mem_device);
 482         if (result) {
 483                 kfree(mem_device);
 484                 return result;
 485         }
 486
 487         /* Set the device state */
 488         mem_device->state = MEMORY_POWER_ON_STATE;
 489
 490         printk(KERN_DEBUG "%s \n", acpi_device_name(device));
 491
 492         if (!acpi_memory_check_device(mem_device)) {
 493                 /* call add_memory func */
 494                 result = acpi_memory_enable_device(mem_device);
 495                 if (result) {
 496                         printk(KERN_ERR PREFIX
 497                                 "Error in acpi_memory_enable_device\n");
 498                         acpi_memory_device_free(mem_device);
 499                 }
 500         }
 501         return result;
 502 }
 503
 504 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 505 {
 506         if (!device || !acpi_driver_data(device))
 507                 return -EINVAL;
 508
 509         acpi_memory_device_free(acpi_driver_data(device));
 510
 511         return 0;
 512 }
 513
 514 /*
 515  * Helper function to check for memory device
 516  */
 517 static acpi_status is_memory_device(acpi_handle handle)
 518 {
 519         char *hardware_id;
 520         acpi_status status;
 521         struct acpi_device_info *info;
 522
 523         status = acpi_get_object_info(handle, &info);
 524         if (ACPI_FAILURE(status))
 525                 return status;
 526
 527         if (!(info->valid & ACPI_VALID_HID)) {
 528                 kfree(info);
 529                 return AE_ERROR;
 530         }
 531
 532         hardware_id = info->hardware_id.string;
 533         if ((hardware_id == NULL) ||
 534             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 535                 status = AE_ERROR;
 536
 537         kfree(info);
 538         return status;
 539 }
 540
 541 static acpi_status
 542 acpi_memory_register_notify_handler(acpi_handle handle,
 543                                     u32 level, void *ctxt, void **retv)
 544 {
 545         acpi_status status;
 546
 547
 548         status = is_memory_device(handle);
 549         if (ACPI_FAILURE(status))
 550                 return AE_OK;   /* continue */
 551
 552         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 553                                              acpi_memory_device_notify, NULL);
 554         /* continue */
 555         return AE_OK;
 556 }
 557
 558 static acpi_status
 559 acpi_memory_deregister_notify_handler(acpi_handle handle,
 560                                       u32 level, void *ctxt, void **retv)
 561 {
 562         acpi_status status;
 563
 564
 565         status = is_memory_device(handle);
 566         if (ACPI_FAILURE(status))
 567                 return AE_OK;   /* continue */
 568
 569         status = acpi_remove_notify_handler(handle,
 570                                             ACPI_SYSTEM_NOTIFY,
 571                                             acpi_memory_device_notify);
 572
 573         return AE_OK;   /* continue */
 574 }
 575
 576 static int __init acpi_memory_device_init(void)
 577 {
 578         int result;
 579         acpi_status status;
 580
 581
 582         result = acpi_bus_register_driver(&acpi_memory_device_driver);
 583
 584         if (result < 0)
 585                 return -ENODEV;
 586
 587         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 588                                      ACPI_UINT32_MAX,
 589                                      acpi_memory_register_notify_handler, NULL,
 590                                      NULL, NULL);
 591
 592         if (ACPI_FAILURE(status)) {
 593                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 594                 acpi_bus_unregister_driver(&acpi_memory_device_driver);
 595                 return -ENODEV;
 596         }
 597
 598         return 0;
 599 }
 600
 601 static void __exit acpi_memory_device_exit(void)
 602 {
 603         acpi_status status;
 604
 605
 606         /*
 607          * Adding this to un-install notification handlers for all the device
 608          * handles.
 609          */
 610         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 611                                      ACPI_UINT32_MAX,
 612                                      acpi_memory_deregister_notify_handler, NULL,
 613                                      NULL, NULL);
 614
 615         if (ACPI_FAILURE(status))
 616                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 617
 618         acpi_bus_unregister_driver(&acpi_memory_device_driver);
 619
 620         return;
 621 }
 622
 623 module_init(acpi_memory_device_init);
 624 module_exit(acpi_memory_device_exit);