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 (node < 0)
 247                         node = memory_add_physaddr_to_nid(info->start_addr);
 248
 249                 result = add_memory(node, info->start_addr, info->length);
 250                 if (result)
 251                         continue;
 252                 info->enabled = 1;
 253                 num_enabled++;
 254         }
 255         if (!num_enabled) {
 256                 printk(KERN_ERR PREFIX "add_memory failed\n");
 257                 mem_device->state = MEMORY_INVALID_STATE;
 258                 return -EINVAL;
 259         }
 260
 261         return result;
 262 }
 263
 264 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 265 {
 266         acpi_status status;
 267         struct acpi_object_list arg_list;
 268         union acpi_object arg;
 269         unsigned long long current_status;
 270
 271
 272         /* Issue the _EJ0 command */
 273         arg_list.count = 1;
 274         arg_list.pointer = &arg;
 275         arg.type = ACPI_TYPE_INTEGER;
 276         arg.integer.value = 1;
 277         status = acpi_evaluate_object(mem_device->device->handle,
 278                                       "_EJ0", &arg_list, NULL);
 279         /* Return on _EJ0 failure */
 280         if (ACPI_FAILURE(status)) {
 281                 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
 282                 return -ENODEV;
 283         }
 284
 285         /* Evalute _STA to check if the device is disabled */
 286         status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
 287                                        NULL, &current_status);
 288         if (ACPI_FAILURE(status))
 289                 return -ENODEV;
 290
 291         /* Check for device status.  Device should be disabled */
 292         if (current_status & ACPI_STA_DEVICE_ENABLED)
 293                 return -EINVAL;
 294
 295         return 0;
 296 }
 297
 298 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 299 {
 300         int result;
 301         struct acpi_memory_info *info, *n;
 302
 303
 304         /*
 305          * Ask the VM to offline this memory range.
 306          * Note: Assume that this function returns zero on success
 307          */
 308         list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 309                 if (info->enabled) {
 310                         result = remove_memory(info->start_addr, info->length);
 311                         if (result)
 312                                 return result;
 313                 }
 314                 kfree(info);
 315         }
 316
 317         /* Power-off and eject the device */
 318         result = acpi_memory_powerdown_device(mem_device);
 319         if (result) {
 320                 /* Set the status of the device to invalid */
 321                 mem_device->state = MEMORY_INVALID_STATE;
 322                 return result;
 323         }
 324
 325         mem_device->state = MEMORY_POWER_OFF_STATE;
 326         return result;
 327 }
 328
 329 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 330 {
 331         struct acpi_memory_device *mem_device;
 332         struct acpi_device *device;
 333
 334
 335         switch (event) {
 336         case ACPI_NOTIFY_BUS_CHECK:
 337                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 338                                   "\nReceived BUS CHECK notification for device\n"));
 339                 /* Fall Through */
 340         case ACPI_NOTIFY_DEVICE_CHECK:
 341                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
 342                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 343                                           "\nReceived DEVICE CHECK notification for device\n"));
 344                 if (acpi_memory_get_device(handle, &mem_device)) {
 345                         printk(KERN_ERR PREFIX "Cannot find driver data\n");
 346                         return;
 347                 }
 348
 349                 if (!acpi_memory_check_device(mem_device)) {
 350                         if (acpi_memory_enable_device(mem_device))
 351                                 printk(KERN_ERR PREFIX
 352                                             "Cannot enable memory device\n");
 353                 }
 354                 break;
 355         case ACPI_NOTIFY_EJECT_REQUEST:
 356                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 357                                   "\nReceived EJECT REQUEST notification for device\n"));
 358
 359                 if (acpi_bus_get_device(handle, &device)) {
 360                         printk(KERN_ERR PREFIX "Device doesn't exist\n");
 361                         break;
 362                 }
 363                 mem_device = acpi_driver_data(device);
 364                 if (!mem_device) {
 365                         printk(KERN_ERR PREFIX "Driver Data is NULL\n");
 366                         break;
 367                 }
 368
 369                 /*
 370                  * Currently disabling memory device from kernel mode
 371                  * TBD: Can also be disabled from user mode scripts
 372                  * TBD: Can also be disabled by Callback registration
 373                  *      with generic sysfs driver
 374                  */
 375                 if (acpi_memory_disable_device(mem_device))
 376                         printk(KERN_ERR PREFIX
 377                                     "Disable memory device\n");
 378                 /*
 379                  * TBD: Invoke acpi_bus_remove to cleanup data structures
 380                  */
 381                 break;
 382         default:
 383                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 384                                   "Unsupported event [0x%x]\n", event));
 385                 break;
 386         }
 387
 388         return;
 389 }
 390
 391 static int acpi_memory_device_add(struct acpi_device *device)
 392 {
 393         int result;
 394         struct acpi_memory_device *mem_device = NULL;
 395
 396
 397         if (!device)
 398                 return -EINVAL;
 399
 400         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 401         if (!mem_device)
 402                 return -ENOMEM;
 403
 404         INIT_LIST_HEAD(&mem_device->res_list);
 405         mem_device->device = device;
 406         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 407         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 408         device->driver_data = mem_device;
 409
 410         /* Get the range from the _CRS */
 411         result = acpi_memory_get_device_resources(mem_device);
 412         if (result) {
 413                 kfree(mem_device);
 414                 return result;
 415         }
 416
 417         /* Set the device state */
 418         mem_device->state = MEMORY_POWER_ON_STATE;
 419
 420         printk(KERN_DEBUG "%s \n", acpi_device_name(device));
 421
 422         return result;
 423 }
 424
 425 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 426 {
 427         struct acpi_memory_device *mem_device = NULL;
 428
 429
 430         if (!device || !acpi_driver_data(device))
 431                 return -EINVAL;
 432
 433         mem_device = acpi_driver_data(device);
 434         kfree(mem_device);
 435
 436         return 0;
 437 }
 438
 439 static int acpi_memory_device_start (struct acpi_device *device)
 440 {
 441         struct acpi_memory_device *mem_device;
 442         int result = 0;
 443
 444         /*
 445          * Early boot code has recognized memory area by EFI/E820.
 446          * If DSDT shows these memory devices on boot, hotplug is not necessary
 447          * for them. So, it just returns until completion of this driver's
 448          * start up.
 449          */
 450         if (!acpi_hotmem_initialized)
 451                 return 0;
 452
 453         mem_device = acpi_driver_data(device);
 454
 455         if (!acpi_memory_check_device(mem_device)) {
 456                 /* call add_memory func */
 457                 result = acpi_memory_enable_device(mem_device);
 458                 if (result)
 459                         printk(KERN_ERR PREFIX
 460                                 "Error in acpi_memory_enable_device\n");
 461         }
 462         return result;
 463 }
 464
 465 /*
 466  * Helper function to check for memory device
 467  */
 468 static acpi_status is_memory_device(acpi_handle handle)
 469 {
 470         char *hardware_id;
 471         acpi_status status;
 472         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 473         struct acpi_device_info *info;
 474
 475
 476         status = acpi_get_object_info(handle, &buffer);
 477         if (ACPI_FAILURE(status))
 478                 return status;
 479
 480         info = buffer.pointer;
 481         if (!(info->valid & ACPI_VALID_HID)) {
 482                 kfree(buffer.pointer);
 483                 return AE_ERROR;
 484         }
 485
 486         hardware_id = info->hardware_id.value;
 487         if ((hardware_id == NULL) ||
 488             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 489                 status = AE_ERROR;
 490
 491         kfree(buffer.pointer);
 492         return status;
 493 }
 494
 495 static acpi_status
 496 acpi_memory_register_notify_handler(acpi_handle handle,
 497                                     u32 level, void *ctxt, void **retv)
 498 {
 499         acpi_status status;
 500
 501
 502         status = is_memory_device(handle);
 503         if (ACPI_FAILURE(status))
 504                 return AE_OK;   /* continue */
 505
 506         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 507                                              acpi_memory_device_notify, NULL);
 508         /* continue */
 509         return AE_OK;
 510 }
 511
 512 static acpi_status
 513 acpi_memory_deregister_notify_handler(acpi_handle handle,
 514                                       u32 level, void *ctxt, void **retv)
 515 {
 516         acpi_status status;
 517
 518
 519         status = is_memory_device(handle);
 520         if (ACPI_FAILURE(status))
 521                 return AE_OK;   /* continue */
 522
 523         status = acpi_remove_notify_handler(handle,
 524                                             ACPI_SYSTEM_NOTIFY,
 525                                             acpi_memory_device_notify);
 526
 527         return AE_OK;   /* continue */
 528 }
 529
 530 static int __init acpi_memory_device_init(void)
 531 {
 532         int result;
 533         acpi_status status;
 534
 535
 536         result = acpi_bus_register_driver(&acpi_memory_device_driver);
 537
 538         if (result < 0)
 539                 return -ENODEV;
 540
 541         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 542                                      ACPI_UINT32_MAX,
 543                                      acpi_memory_register_notify_handler,
 544                                      NULL, NULL);
 545
 546         if (ACPI_FAILURE(status)) {
 547                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 548                 acpi_bus_unregister_driver(&acpi_memory_device_driver);
 549                 return -ENODEV;
 550         }
 551
 552         acpi_hotmem_initialized = 1;
 553         return 0;
 554 }
 555
 556 static void __exit acpi_memory_device_exit(void)
 557 {
 558         acpi_status status;
 559
 560
 561         /*
 562          * Adding this to un-install notification handlers for all the device
 563          * handles.
 564          */
 565         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 566                                      ACPI_UINT32_MAX,
 567                                      acpi_memory_deregister_notify_handler,
 568                                      NULL, NULL);
 569
 570         if (ACPI_FAILURE(status))
 571                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 572
 573         acpi_bus_unregister_driver(&acpi_memory_device_driver);
 574
 575         return;
 576 }
 577
 578 module_init(acpi_memory_device_init);
 579 module_exit(acpi_memory_device_exit);