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