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
  57 static const struct acpi_device_id memory_device_ids[] = {
  58         {ACPI_MEMORY_DEVICE_HID, 0},
  59         {"", 0},
  60 };
  61 MODULE_DEVICE_TABLE(acpi, memory_device_ids);
  62
  63 static struct acpi_driver acpi_memory_device_driver = {
  64         .name = "acpi_memhotplug",
  65         .class = ACPI_MEMORY_DEVICE_CLASS,
  66         .ids = memory_device_ids,
  67         .ops = {
  68                 .add = acpi_memory_device_add,
  69                 .remove = acpi_memory_device_remove,
  70                 },
  71 };
  72
  73 struct acpi_memory_info {
  74         struct list_head list;
  75         u64 start_addr;         /* Memory Range start physical addr */
  76         u64 length;             /* Memory Range length */
  77         unsigned short caching; /* memory cache attribute */
  78         unsigned short write_protect;   /* memory read/write attribute */
  79         unsigned int enabled:1;
  80 };
  81
  82 struct acpi_memory_device {
  83         struct acpi_device * device;
  84         unsigned int state;     /* State of the memory device */
  85         struct list_head res_list;
  86 };
  87
  88 static int acpi_hotmem_initialized;
  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 int
 128 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 129 {
 130         acpi_status status;
 131         struct acpi_memory_info *info, *n;
 132
 133
 134         if (!list_empty(&mem_device->res_list))
 135                 return 0;
 136
 137         status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 138                                      acpi_memory_get_resource, mem_device);
 139         if (ACPI_FAILURE(status)) {
 140                 list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 141                         kfree(info);
 142                 INIT_LIST_HEAD(&mem_device->res_list);
 143                 return -EINVAL;
 144         }
 145
 146         return 0;
 147 }
 148
 149 static int
 150 acpi_memory_get_device(acpi_handle handle,
 151                        struct acpi_memory_device **mem_device)
 152 {
 153         acpi_status status;
 154         acpi_handle phandle;
 155         struct acpi_device *device = NULL;
 156         struct acpi_device *pdevice = NULL;
 157         int result;
 158
 159
 160         if (!acpi_bus_get_device(handle, &device) && device)
 161                 goto end;
 162
 163         status = acpi_get_parent(handle, &phandle);
 164         if (ACPI_FAILURE(status)) {
 165                 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
 166                 return -EINVAL;
 167         }
 168
 169         /* Get the parent device */
 170         result = acpi_bus_get_device(phandle, &pdevice);
 171         if (result) {
 172                 printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
 173                 return -EINVAL;
 174         }
 175
 176         /*
 177          * Now add the notified device.  This creates the acpi_device
 178          * and invokes .add function
 179          */
 180         result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
 181         if (result) {
 182                 printk(KERN_WARNING PREFIX "Cannot add acpi bus");
 183                 return -EINVAL;
 184         }
 185
 186       end:
 187         *mem_device = acpi_driver_data(device);
 188         if (!(*mem_device)) {
 189                 printk(KERN_ERR "\n driver data not found");
 190                 return -ENODEV;
 191         }
 192
 193         return 0;
 194 }
 195
 196 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 197 {
 198         unsigned long long current_status;
 199
 200         /* Get device present/absent information from the _STA */
 201         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
 202                                                NULL, &current_status)))
 203                 return -ENODEV;
 204         /*
 205          * Check for device status. Device should be
 206          * present/enabled/functioning.
 207          */
 208         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 209               && (current_status & ACPI_STA_DEVICE_ENABLED)
 210               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 211                 return -ENODEV;
 212
 213         return 0;
 214 }
 215
 216 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 217 {
 218         int result, num_enabled = 0;
 219         struct acpi_memory_info *info;
 220         int node;
 221
 222
 223         /* Get the range from the _CRS */
 224         result = acpi_memory_get_device_resources(mem_device);
 225         if (result) {
 226                 printk(KERN_ERR PREFIX "get_device_resources failed\n");
 227                 mem_device->state = MEMORY_INVALID_STATE;
 228                 return result;
 229         }
 230
 231         node = acpi_get_node(mem_device->device->handle);
 232         /*
 233          * Tell the VM there is more memory here...
 234          * Note: Assume that this function returns zero on success
 235          * We don't have memory-hot-add rollback function,now.
 236          * (i.e. memory-hot-remove function)
 237          */
 238         list_for_each_entry(info, &mem_device->res_list, list) {
 239                 if (info->enabled) { /* just sanity check...*/
 240                         num_enabled++;
 241                         continue;
 242                 }
 243                 /*
 244                  * If the memory block size is zero, please ignore it.
 245                  * Don't try to do the following memory hotplug flowchart.
 246                  */
 247                 if (!info->length)
 248                         continue;
 249                 if (node < 0)
 250                         node = memory_add_physaddr_to_nid(info->start_addr);
 251
 252                 result = add_memory(node, info->start_addr, info->length);
 253                 if (result)
 254                         continue;
 255                 info->enabled = 1;
 256                 num_enabled++;
 257         }
 258         if (!num_enabled) {
 259                 printk(KERN_ERR PREFIX "add_memory failed\n");
 260                 mem_device->state = MEMORY_INVALID_STATE;
 261                 return -EINVAL;
 262         }
 263         /*
 264          * Sometimes the memory device will contain several memory blocks.
 265          * When one memory block is hot-added to the system memory, it will
 266          * be regarded as a success.
 267          * Otherwise if the last memory block can't be hot-added to the system
 268          * memory, it will be failure and the memory device can't be bound with
 269          * driver.
 270          */
 271         return 0;
 272 }
 273
 274 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 275 {
 276         acpi_status status;
 277         struct acpi_object_list arg_list;
 278         union acpi_object arg;
 279         unsigned long long current_status;
 280
 281
 282         /* Issue the _EJ0 command */
 283         arg_list.count = 1;
 284         arg_list.pointer = &arg;
 285         arg.type = ACPI_TYPE_INTEGER;
 286         arg.integer.value = 1;
 287         status = acpi_evaluate_object(mem_device->device->handle,
 288                                       "_EJ0", &arg_list, NULL);
 289         /* Return on _EJ0 failure */
 290         if (ACPI_FAILURE(status)) {
 291                 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
 292                 return -ENODEV;
 293         }
 294
 295         /* Evalute _STA to check if the device is disabled */
 296         status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
 297                                        NULL, &current_status);
 298         if (ACPI_FAILURE(status))
 299                 return -ENODEV;
 300
 301         /* Check for device status.  Device should be disabled */
 302         if (current_status & ACPI_STA_DEVICE_ENABLED)
 303                 return -EINVAL;
 304
 305         return 0;
 306 }
 307
 308 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 309 {
 310         int result;
 311         struct acpi_memory_info *info, *n;
 312
 313
 314         /*
 315          * Ask the VM to offline this memory range.
 316          * Note: Assume that this function returns zero on success
 317          */
 318         list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 319                 if (info->enabled) {
 320                         result = remove_memory(info->start_addr, info->length);
 321                         if (result)
 322                                 return result;
 323                 }
 324                 kfree(info);
 325         }
 326
 327         /* Power-off and eject the device */
 328         result = acpi_memory_powerdown_device(mem_device);
 329         if (result) {
 330                 /* Set the status of the device to invalid */
 331                 mem_device->state = MEMORY_INVALID_STATE;
 332                 return result;
 333         }
 334
 335         mem_device->state = MEMORY_POWER_OFF_STATE;
 336         return result;
 337 }
 338
 339 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 340 {
 341         struct acpi_memory_device *mem_device;
 342         struct acpi_device *device;
 343
 344
 345         switch (event) {
 346         case ACPI_NOTIFY_BUS_CHECK:
 347                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 348                                   "\nReceived BUS CHECK notification for device\n"));
 349                 /* Fall Through */
 350         case ACPI_NOTIFY_DEVICE_CHECK:
 351                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
 352                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 353                                           "\nReceived DEVICE CHECK notification for device\n"));
 354                 if (acpi_memory_get_device(handle, &mem_device)) {
 355                         printk(KERN_ERR PREFIX "Cannot find driver data\n");
 356                         return;
 357                 }
 358
 359                 if (!acpi_memory_check_device(mem_device)) {
 360                         if (acpi_memory_enable_device(mem_device))
 361                                 printk(KERN_ERR PREFIX
 362                                             "Cannot enable memory device\n");
 363                 }
 364                 break;
 365         case ACPI_NOTIFY_EJECT_REQUEST:
 366                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 367                                   "\nReceived EJECT REQUEST notification for device\n"));
 368
 369                 if (acpi_bus_get_device(handle, &device)) {
 370                         printk(KERN_ERR PREFIX "Device doesn't exist\n");
 371                         break;
 372                 }
 373                 mem_device = acpi_driver_data(device);
 374                 if (!mem_device) {
 375                         printk(KERN_ERR PREFIX "Driver Data is NULL\n");
 376                         break;
 377                 }
 378
 379                 /*
 380                  * Currently disabling memory device from kernel mode
 381                  * TBD: Can also be disabled from user mode scripts
 382                  * TBD: Can also be disabled by Callback registration
 383                  *      with generic sysfs driver
 384                  */
 385                 if (acpi_memory_disable_device(mem_device))
 386                         printk(KERN_ERR PREFIX
 387                                     "Disable memory device\n");
 388                 /*
 389                  * TBD: Invoke acpi_bus_remove to cleanup data structures
 390                  */
 391                 break;
 392         default:
 393                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 394                                   "Unsupported event [0x%x]\n", event));
 395                 break;
 396         }
 397
 398         return;
 399 }
 400
 401 static int acpi_memory_device_add(struct acpi_device *device)
 402 {
 403         int result;
 404         struct acpi_memory_device *mem_device = NULL;
 405
 406
 407         if (!device)
 408                 return -EINVAL;
 409
 410         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 411         if (!mem_device)
 412                 return -ENOMEM;
 413
 414         INIT_LIST_HEAD(&mem_device->res_list);
 415         mem_device->device = device;
 416         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 417         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 418         device->driver_data = mem_device;
 419
 420         /* Get the range from the _CRS */
 421         result = acpi_memory_get_device_resources(mem_device);
 422         if (result) {
 423                 kfree(mem_device);
 424                 return result;
 425         }
 426
 427         /* Set the device state */
 428         mem_device->state = MEMORY_POWER_ON_STATE;
 429
 430         printk(KERN_DEBUG "%s \n", acpi_device_name(device));
 431
 432         /*
 433          * Early boot code has recognized memory area by EFI/E820.
 434          * If DSDT shows these memory devices on boot, hotplug is not necessary
 435          * for them. So, it just returns until completion of this driver's
 436          * start up.
 437          */
 438         if (!acpi_hotmem_initialized)
 439                 return 0;
 440
 441         if (!acpi_memory_check_device(mem_device)) {
 442                 /* call add_memory func */
 443                 result = acpi_memory_enable_device(mem_device);
 444                 if (result)
 445                         printk(KERN_ERR PREFIX
 446                                 "Error in acpi_memory_enable_device\n");
 447         }
 448         return result;
 449 }
 450
 451 static int acpi_memory_device_remove(struct acpi_device *device, int type)
 452 {
 453         struct acpi_memory_device *mem_device = NULL;
 454
 455
 456         if (!device || !acpi_driver_data(device))
 457                 return -EINVAL;
 458
 459         mem_device = acpi_driver_data(device);
 460         kfree(mem_device);
 461
 462         return 0;
 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_device_info *info;
 473
 474         status = acpi_get_object_info(handle, &info);
 475         if (ACPI_FAILURE(status))
 476                 return status;
 477
 478         if (!(info->valid & ACPI_VALID_HID)) {
 479                 kfree(info);
 480                 return AE_ERROR;
 481         }
 482
 483         hardware_id = info->hardware_id.string;
 484         if ((hardware_id == NULL) ||
 485             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 486                 status = AE_ERROR;
 487
 488         kfree(info);
 489         return status;
 490 }
 491
 492 static acpi_status
 493 acpi_memory_register_notify_handler(acpi_handle handle,
 494                                     u32 level, void *ctxt, void **retv)
 495 {
 496         acpi_status status;
 497
 498
 499         status = is_memory_device(handle);
 500         if (ACPI_FAILURE(status))
 501                 return AE_OK;   /* continue */
 502
 503         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 504                                              acpi_memory_device_notify, NULL);
 505         /* continue */
 506         return AE_OK;
 507 }
 508
 509 static acpi_status
 510 acpi_memory_deregister_notify_handler(acpi_handle handle,
 511                                       u32 level, void *ctxt, void **retv)
 512 {
 513         acpi_status status;
 514
 515
 516         status = is_memory_device(handle);
 517         if (ACPI_FAILURE(status))
 518                 return AE_OK;   /* continue */
 519
 520         status = acpi_remove_notify_handler(handle,
 521                                             ACPI_SYSTEM_NOTIFY,
 522                                             acpi_memory_device_notify);
 523
 524         return AE_OK;   /* continue */
 525 }
 526
 527 static int __init acpi_memory_device_init(void)
 528 {
 529         int result;
 530         acpi_status status;
 531
 532
 533         result = acpi_bus_register_driver(&acpi_memory_device_driver);
 534
 535         if (result < 0)
 536                 return -ENODEV;
 537
 538         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 539                                      ACPI_UINT32_MAX,
 540                                      acpi_memory_register_notify_handler, NULL,
 541                                      NULL, NULL);
 542
 543         if (ACPI_FAILURE(status)) {
 544                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 545                 acpi_bus_unregister_driver(&acpi_memory_device_driver);
 546                 return -ENODEV;
 547         }
 548
 549         acpi_hotmem_initialized = 1;
 550         return 0;
 551 }
 552
 553 static void __exit acpi_memory_device_exit(void)
 554 {
 555         acpi_status status;
 556
 557
 558         /*
 559          * Adding this to un-install notification handlers for all the device
 560          * handles.
 561          */
 562         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 563                                      ACPI_UINT32_MAX,
 564                                      acpi_memory_deregister_notify_handler, NULL,
 565                                      NULL, NULL);
 566
 567         if (ACPI_FAILURE(status))
 568                 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 569
 570         acpi_bus_unregister_driver(&acpi_memory_device_driver);
 571
 572         return;
 573 }
 574
 575 module_init(acpi_memory_device_init);
 576 module_exit(acpi_memory_device_exit);