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 };
  82
  83 struct 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
  89 static int acpi_hotmem_initialized;
  90
  91 static acpi_status
  92 acpi_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
 128 static void
 129 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
 130 {
 131         struct acpi_memory_info *info, *n;
 132
 133         list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 134                 kfree(info);
 135         INIT_LIST_HEAD(&mem_device->res_list);
 136 }
 137
 138 static int
 139 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 140 {
 141         acpi_status status;
 142
 143         if (!list_empty(&mem_device->res_list))
 144                 return 0;
 145
 146         status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 147                                      acpi_memory_get_resource, mem_device);
 148         if (ACPI_FAILURE(status)) {
 149                 acpi_memory_free_device_resources(mem_device);
 150                 return -EINVAL;
 151         }
 152
 153         return 0;
 154 }
 155
 156 static int
 157 acpi_memory_get_device(acpi_handle handle,
 158                        struct acpi_memory_device **mem_device)
 159 {
 160         acpi_status status;
 161         acpi_handle phandle;
 162         struct acpi_device *device = NULL;
 163         struct acpi_device *pdevice = NULL;
 164         int result;
 165
 166
 167         if (!acpi_bus_get_device(handle, &device) && device)
 168                 goto end;
 169
 170         status = acpi_get_parent(handle, &phandle);
 171         if (ACPI_FAILURE(status)) {
 172                 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
 173                 return -EINVAL;
 174         }
 175
 176         /* Get the parent device */
 177         result = acpi_bus_get_device(phandle, &pdevice);
 178         if (result) {
 179                 printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
 180                 return -EINVAL;
 181         }
 182
 183         /*
 184          * Now add the notified device.  This creates the acpi_device
 185          * and invokes .add function
 186          */
 187         result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
 188         if (result) {
 189                 printk(KERN_WARNING PREFIX "Cannot add acpi bus");
 190                 return -EINVAL;
 191         }
 192
 193       end:
 194         *mem_device = acpi_driver_data(device);
 195         if (!(*mem_device)) {
 196                 printk(KERN_ERR "\n driver data not found");
 197                 return -ENODEV;
 198         }
 199
 200         return 0;
 201 }
 202
 203 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 204 {
 205         unsigned long long current_status;
 206
 207         /* Get device present/absent information from the _STA */
 208         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
 209                                                NULL, &current_status)))
 210                 return -ENODEV;
 211         /*
 212          * Check for device status. Device should be
 213          * present/enabled/functioning.
 214          */
 215         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 216               && (current_status & ACPI_STA_DEVICE_ENABLED)
 217               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 218                 return -ENODEV;
 219
 220         return 0;
 221 }
 222
 223 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 224 {
 225         int result, num_enabled = 0;
 226         struct acpi_memory_info *info;
 227         int node;
 228
 229
 230         /* Get the range from the _CRS */
 231         result = acpi_memory_get_device_resources(mem_device);
 232         if (result) {
 233                 printk(KERN_ERR PREFIX "get_device_resources failed\n");
 234                 mem_device->state = MEMORY_INVALID_STATE;
 235                 return result;
 236         }
 237
 238         node = acpi_get_node(mem_device->device->handle);
 239         /*
 240          * Tell the VM there is more memory here...
 241          * Note: Assume that this function returns zero on success
 242          * We don't have memory-hot-add rollback function,now.
 243          * (i.e. memory-hot-remove function)
 244          */
 245         list_for_each_entry(info, &mem_device->res_list, list) {
 246                 if (info->enabled) { /* just sanity check...*/
 247                         num_enabled++;
 248                         continue;
 249                 }
 250                 /*
 251                  * If the memory block size is zero, please ignore it.
 252                  * Don't try to do the following memory hotplug flowchart.
 253                  */
 254                 if (!info->length)
 255                         continue;
 256                 if (node < 0)
 257                         node = memory_add_physaddr_to_nid(info->start_addr);
 258
 259                 result = add_memory(node, info->start_addr, info->length);
 260                 if (result)
 261                         continue;
 262                 info->enabled = 1;
 263                 num_enabled++;
 264         }
 265         if (!num_enabled) {
 266                 printk(KERN_ERR PREFIX "add_memory failed\n");
 267                 mem_device->state = MEMORY_INVALID_STATE;
 268                 return -EINVAL;
 269         }
 270         /*
 271          * Sometimes the memory device will contain several memory blocks.
 272          * When one memory block is hot-added to the system memory, it will
 273          * be regarded as a success.
 274          * Otherwise if the last memory block can't be hot-added to the system
 275          * memory, it will be failure and the memory device can't be bound with
 276          * driver.
 277          */
 278         return 0;
 279 }
 280
 281 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 282 {
 283         acpi_status status;
 284         struct acpi_object_list arg_list;
 285         union acpi_object arg;
 286         unsigned long long current_status;
 287
 288
 289         /* Issue the _EJ0 command */
 290         arg_list.count = 1;
 291         arg_list.pointer = &arg;
 292         arg.type = ACPI_TYPE_INTEGER;
 293         arg.integer.value = 1;
 294         status = acpi_evaluate_object(mem_device->device->handle,
 295                                       "_EJ0", &arg_list, NULL);
 296         /* Return on _EJ0 failure */
 297         if (ACPI_FAILURE(status)) {
 298                 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
 299                 return -ENODEV;
 300         }
 301
 302         /* Evalute _STA to check if the device is disabled */
 303         status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
 304                                        NULL, &current_status);
 305         if (ACPI_FAILURE(status))
 306                 return -ENODEV;
 307
 308         /* Check for device status.  Device should be disabled */
 309         if (current_status & ACPI_STA_DEVICE_ENABLED)
 310                 return -EINVAL;
 311
 312         return 0;
 313 }
 314
 315 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 316 {
 317         int result;
 318         struct acpi_memory_info *info, *n;
 319
 320
 321         /*
 322          * Ask the VM to offline this memory range.
 323          * Note: Assume that this function returns zero on success
 324          */
 325         list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 326                 if (info->enabled) {
 327                         result = remove_memory(info->start_addr, info->length);
 328                         if (result)
 329                                 return result;
 330                 }
 331                 list_del(&info->list);
 332                 kfree(info);
 333         }
 334
 335         /* Power-off and eject the device */
 336         result = acpi_memory_powerdown_device(mem_device);
 337         if (result) {
 338                 /* Set the status of the device to invalid */
 339                 mem_device->state = MEMORY_INVALID_STATE;
 340                 return result;
 341         }
 342
 343         mem_device->state = MEMORY_POWER_OFF_STATE;
 344         return result;
 345 }
 346
 347 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 348 {
 349         struct acpi_memory_device *mem_device;
 350         struct acpi_device *device;
 351         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 352
 353         switch (event) {
 354         case ACPI_NOTIFY_BUS_CHECK:
 355                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 356                                   "\nReceived BUS CHECK notification for device\n"));
 357                 /* Fall Through */
 358         case ACPI_NOTIFY_DEVICE_CHECK:
 359                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
 360                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 361                                           "\nReceived DEVICE CHECK notification for device\n"));
 362                 if (acpi_memory_get_device(handle, &mem_device)) {
 363                         printk(KERN_ERR PREFIX "Cannot find driver data\n");
 364                         break;
 365                 }
 366
 367                 if (acpi_memory_check_device(mem_device))
 368                         break;
 369
 370                 if (acpi_memory_enable_device(mem_device)) {
 371                         printk(KERN_ERR PREFIX "Cannot enable memory device\n");
 372                         break;
 373                 }
 374
 375                 ost_code = ACPI_OST_SC_SUCCESS;
 376                 break;
 377
 378         case ACPI_NOTIFY_EJECT_REQUEST:
 379                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 380                                   "\nReceived EJECT REQUEST notification for device\n"));
 381
 382                 if (acpi_bus_get_device(handle, &device)) {
 383                         printk(KERN_ERR PREFIX "Device doesn't exist\n");
 384                         break;
 385                 }
 386                 mem_device = acpi_driver_data(device);
 387                 if (!mem_device) {
 388                         printk(KERN_ERR PREFIX "Driver Data is NULL\n");
 389                         break;
 390                 }
 391
 392                 /*
 393                  * Currently disabling memory device from kernel mode
 394                  * TBD: Can also be disabled from user mode scripts
 395                  * TBD: Can also be disabled by Callback registration
 396                  *      with generic sysfs driver
 397                  */
 398                 if (acpi_memory_disable_device(mem_device)) {
 399                         printk(KERN_ERR PREFIX "Disable memory device\n");
 400                         /*
 401                          * If _EJ0 was called but failed, _OST is not
 402                          * necessary.
 403                          */
 404                         if (mem_device->state == MEMORY_INVALID_STATE)
 405                                 return;
 406
 407                         break;
 408                 }
 409
 410                 /*
 411                  * TBD: Invoke acpi_bus_remove to cleanup data structures
 412                  */
 413
 414                 /* _EJ0 succeeded; _OST is not necessary */
 415                 return;
 416
 417         default:
 418                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 419                                   "Unsupported event [0x%x]\n", event));
 420
 421                 /* non-hotplug event; possibly handled by other handler */
 422                 return;
 423         }
 424
 425         /* Inform firmware that the hotplug operation has completed */
 426         (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
 427         return;
 428 }
 429
 430 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
 431 {
 432         if (!mem_device)
 433                 return;
 434
 435         acpi_memory_free_device_resources(mem_device);
 436         kfree(mem_device);
 437 }
 438
 439 static int acpi_memory_device_add(struct acpi_device *device)
 440 {
 441         int result;
 442         struct acpi_memory_device *mem_device = NULL;
 443
 444
 445         if (!device)
 446                 return -EINVAL;
 447
 448         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 449         if (!mem_device)
 450                 return -ENOMEM;
 451
 452         INIT_LIST_HEAD(&mem_device->res_list);
 453         mem_device->device = device;
 454         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 455         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 456         device->driver_data = mem_device;
 457
 458         /* Get the range from the _CRS */
 459         result = acpi_memory_get_device_resources(mem_device);
 460         if (result) {
 461                 kfree(mem_device);
 462                 return result;
 463         }
 464
 465         /* Set the device state */
 466         mem_device->state = MEMORY_POWER_ON_STATE;
 467
 468         printk(KERN_DEBUG "%s \n", acpi_device_name(device));
 469
 470         /*
 471          * Early boot code has recognized memory area by EFI/E820.
 472          * If DSDT shows these memory devices on boot, hotplug is not necessary
 473          * for them. So, it just returns until completion of this driver's
 474          * start up.
 475          */
 476         if (!acpi_hotmem_initialized)
 477                 return 0;
 478
 479         if (!acpi_memory_check_device(mem_device)) {
 480                 /* call add_memory func */
 481                 result = acpi_memory_enable_device(mem_device);
 482                 if (result) {
 483                         printk(KERN_ERR PREFIX
 484                                 "Error in acpi_memory_enable_device\n");
 485                         acpi_memory_device_free(mem_device);
 486                 }
 487         }
 488         return result;
 489 }
 490
 491 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 492 {
 493         if (!device || !acpi_driver_data(device))
 494                 return -EINVAL;
 495
 496         acpi_memory_device_free(acpi_driver_data(device));
 497
 498         return 0;
 499 }
 500
 501 /*
 502  * Helper function to check for memory device
 503  */
 504 static acpi_status is_memory_device(acpi_handle handle)
 505 {
 506         char *hardware_id;
 507         acpi_status status;
 508         struct acpi_device_info *info;
 509
 510         status = acpi_get_object_info(handle, &info);
 511         if (ACPI_FAILURE(status))
 512                 return status;
 513
 514         if (!(info->valid & ACPI_VALID_HID)) {
 515                 kfree(info);
 516                 return AE_ERROR;
 517         }
 518
 519         hardware_id = info->hardware_id.string;
 520         if ((hardware_id == NULL) ||
 521             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 522                 status = AE_ERROR;
 523
 524         kfree(info);
 525         return status;
 526 }
 527
 528 static acpi_status
 529 acpi_memory_register_notify_handler(acpi_handle handle,
 530                                     u32 level, void *ctxt, void **retv)
 531 {
 532         acpi_status status;
 533
 534
 535         status = is_memory_device(handle);
 536         if (ACPI_FAILURE(status))
 537                 return AE_OK;   /* continue */
 538
 539         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 540                                              acpi_memory_device_notify, NULL);
 541         /* continue */
 542         return AE_OK;
 543 }
 544
 545 static acpi_status
 546 acpi_memory_deregister_notify_handler(acpi_handle handle,
 547                                       u32 level, void *ctxt, void **retv)
 548 {
 549         acpi_status status;
 550
 551
 552         status = is_memory_device(handle);
 553         if (ACPI_FAILURE(status))
 554                 return AE_OK;   /* continue */
 555
 556         status = acpi_remove_notify_handler(handle,
 557                                             ACPI_SYSTEM_NOTIFY,
 558                                             acpi_memory_device_notify);
 559
 560         return AE_OK;   /* continue */
 561 }
 562
 563 static int __init acpi_memory_device_init(void)
 564 {
 565         int result;
 566         acpi_status status;
 567
 568
 569         result = acpi_bus_register_driver(&acpi_memory_device_driver);
 570
 571         if (result < 0)
 572                 return -ENODEV;
 573
 574         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 575                                      ACPI_UINT32_MAX,
 576                                      acpi_memory_register_notify_handler, NULL,
 577                                      NULL, NULL);
 578
 579         if (ACPI_FAILURE(status)) {
 580                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 581                 acpi_bus_unregister_driver(&acpi_memory_device_driver);
 582                 return -ENODEV;
 583         }
 584
 585         acpi_hotmem_initialized = 1;
 586         return 0;
 587 }
 588
 589 static void __exit acpi_memory_device_exit(void)
 590 {
 591         acpi_status status;
 592
 593
 594         /*
 595          * Adding this to un-install notification handlers for all the device
 596          * handles.
 597          */
 598         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 599                                      ACPI_UINT32_MAX,
 600                                      acpi_memory_deregister_notify_handler, NULL,
 601                                      NULL, NULL);
 602
 603         if (ACPI_FAILURE(status))
 604                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 605
 606         acpi_bus_unregister_driver(&acpi_memory_device_driver);
 607
 608         return;
 609 }
 610
 611 module_init(acpi_memory_device_init);
 612 module_exit(acpi_memory_device_exit);