drivers/platform/x86/wmi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ACPI-WMI mapping driver
   4  *
   5  *  Copyright (C) 2007-2008 Carlos Corbacho <[email protected]>
   6  *
   7  *  GUID parsing code from ldm.c is:
   8  *   Copyright (C) 2001,2002 Richard Russon <[email protected]>
   9  *   Copyright (c) 2001-2007 Anton Altaparmakov
  10  *   Copyright (C) 2001,2002 Jakob Kemi <[email protected]>
  11  *
  12  *  WMI bus infrastructure by Andrew Lutomirski and Darren Hart:
  13  *    Copyright (C) 2015 Andrew Lutomirski
  14  *    Copyright (C) 2017 VMware, Inc. All Rights Reserved.
  15  */
  16
  17 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  18
  19 #include <linux/acpi.h>
  20 #include <linux/bits.h>
  21 #include <linux/build_bug.h>
  22 #include <linux/device.h>
  23 #include <linux/init.h>
  24 #include <linux/kernel.h>
  25 #include <linux/list.h>
  26 #include <linux/module.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/rwsem.h>
  29 #include <linux/slab.h>
  30 #include <linux/sysfs.h>
  31 #include <linux/types.h>
  32 #include <linux/uuid.h>
  33 #include <linux/wmi.h>
  34 #include <linux/fs.h>
  35
  36 MODULE_AUTHOR("Carlos Corbacho");
  37 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
  38 MODULE_LICENSE("GPL");
  39
  40 static LIST_HEAD(wmi_block_list);
  41
  42 struct guid_block {
  43         guid_t guid;
  44         union {
  45                 char object_id[2];
  46                 struct {
  47                         unsigned char notify_id;
  48                         unsigned char reserved;
  49                 };
  50         };
  51         u8 instance_count;
  52         u8 flags;
  53 } __packed;
  54 static_assert(sizeof(typeof_member(struct guid_block, guid)) == 16);
  55 static_assert(sizeof(struct guid_block) == 20);
  56 static_assert(__alignof__(struct guid_block) == 1);
  57
  58 enum {  /* wmi_block flags */
  59         WMI_READ_TAKES_NO_ARGS,
  60         WMI_GUID_DUPLICATED,
  61         WMI_NO_EVENT_DATA,
  62 };
  63
  64 struct wmi_block {
  65         struct wmi_device dev;
  66         struct list_head list;
  67         struct guid_block gblock;
  68         struct acpi_device *acpi_device;
  69         struct rw_semaphore notify_lock;        /* Protects notify callback add/remove */
  70         wmi_notify_handler handler;
  71         void *handler_data;
  72         bool driver_ready;
  73         unsigned long flags;
  74 };
  75
  76
  77 /*
  78  * If the GUID data block is marked as expensive, we must enable and
  79  * explicitily disable data collection.
  80  */
  81 #define ACPI_WMI_EXPENSIVE   BIT(0)
  82 #define ACPI_WMI_METHOD      BIT(1)     /* GUID is a method */
  83 #define ACPI_WMI_STRING      BIT(2)     /* GUID takes & returns a string */
  84 #define ACPI_WMI_EVENT       BIT(3)     /* GUID is an event */
  85
  86 static const struct acpi_device_id wmi_device_ids[] = {
  87         {"PNP0C14", 0},
  88         {"pnp0c14", 0},
  89         { }
  90 };
  91 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
  92
  93 #define dev_to_wblock(__dev)    container_of_const(__dev, struct wmi_block, dev.dev)
  94 #define dev_to_wdev(__dev)      container_of_const(__dev, struct wmi_device, dev)
  95
  96 /*
  97  * GUID parsing functions
  98  */
  99
 100 static bool guid_parse_and_compare(const char *string, const guid_t *guid)
 101 {
 102         guid_t guid_input;
 103
 104         if (guid_parse(string, &guid_input))
 105                 return false;
 106
 107         return guid_equal(&guid_input, guid);
 108 }
 109
 110 static const void *find_guid_context(struct wmi_block *wblock,
 111                                      struct wmi_driver *wdriver)
 112 {
 113         const struct wmi_device_id *id;
 114
 115         id = wdriver->id_table;
 116         if (!id)
 117                 return NULL;
 118
 119         while (*id->guid_string) {
 120                 if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
 121                         return id->context;
 122                 id++;
 123         }
 124         return NULL;
 125 }
 126
 127 static acpi_status wmi_method_enable(struct wmi_block *wblock, bool enable)
 128 {
 129         struct guid_block *block;
 130         char method[5];
 131         acpi_status status;
 132         acpi_handle handle;
 133
 134         block = &wblock->gblock;
 135         handle = wblock->acpi_device->handle;
 136
 137         snprintf(method, 5, "WE%02X", block->notify_id);
 138         status = acpi_execute_simple_method(handle, method, enable);
 139         if (status == AE_NOT_FOUND)
 140                 return AE_OK;
 141
 142         return status;
 143 }
 144
 145 #define WMI_ACPI_METHOD_NAME_SIZE 5
 146
 147 static inline void get_acpi_method_name(const struct wmi_block *wblock,
 148                                         const char method,
 149                                         char buffer[static WMI_ACPI_METHOD_NAME_SIZE])
 150 {
 151         static_assert(ARRAY_SIZE(wblock->gblock.object_id) == 2);
 152         static_assert(WMI_ACPI_METHOD_NAME_SIZE >= 5);
 153
 154         buffer[0] = 'W';
 155         buffer[1] = method;
 156         buffer[2] = wblock->gblock.object_id[0];
 157         buffer[3] = wblock->gblock.object_id[1];
 158         buffer[4] = '\0';
 159 }
 160
 161 static inline acpi_object_type get_param_acpi_type(const struct wmi_block *wblock)
 162 {
 163         if (wblock->gblock.flags & ACPI_WMI_STRING)
 164                 return ACPI_TYPE_STRING;
 165         else
 166                 return ACPI_TYPE_BUFFER;
 167 }
 168
 169 static int wmidev_match_guid(struct device *dev, const void *data)
 170 {
 171         struct wmi_block *wblock = dev_to_wblock(dev);
 172         const guid_t *guid = data;
 173
 174         /* Legacy GUID-based functions are restricted to only see
 175          * a single WMI device for each GUID.
 176          */
 177         if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags))
 178                 return 0;
 179
 180         if (guid_equal(guid, &wblock->gblock.guid))
 181                 return 1;
 182
 183         return 0;
 184 }
 185
 186 static const struct bus_type wmi_bus_type;
 187
 188 static struct wmi_device *wmi_find_device_by_guid(const char *guid_string)
 189 {
 190         struct device *dev;
 191         guid_t guid;
 192         int ret;
 193
 194         ret = guid_parse(guid_string, &guid);
 195         if (ret < 0)
 196                 return ERR_PTR(ret);
 197
 198         dev = bus_find_device(&wmi_bus_type, NULL, &guid, wmidev_match_guid);
 199         if (!dev)
 200                 return ERR_PTR(-ENODEV);
 201
 202         return dev_to_wdev(dev);
 203 }
 204
 205 static void wmi_device_put(struct wmi_device *wdev)
 206 {
 207         put_device(&wdev->dev);
 208 }
 209
 210 /*
 211  * Exported WMI functions
 212  */
 213
 214 /**
 215  * wmi_instance_count - Get number of WMI object instances
 216  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 217  *
 218  * Get the number of WMI object instances.
 219  *
 220  * Returns: Number of WMI object instances or negative error code.
 221  */
 222 int wmi_instance_count(const char *guid_string)
 223 {
 224         struct wmi_device *wdev;
 225         int ret;
 226
 227         wdev = wmi_find_device_by_guid(guid_string);
 228         if (IS_ERR(wdev))
 229                 return PTR_ERR(wdev);
 230
 231         ret = wmidev_instance_count(wdev);
 232         wmi_device_put(wdev);
 233
 234         return ret;
 235 }
 236 EXPORT_SYMBOL_GPL(wmi_instance_count);
 237
 238 /**
 239  * wmidev_instance_count - Get number of WMI object instances
 240  * @wdev: A wmi bus device from a driver
 241  *
 242  * Get the number of WMI object instances.
 243  *
 244  * Returns: Number of WMI object instances.
 245  */
 246 u8 wmidev_instance_count(struct wmi_device *wdev)
 247 {
 248         struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 249
 250         return wblock->gblock.instance_count;
 251 }
 252 EXPORT_SYMBOL_GPL(wmidev_instance_count);
 253
 254 /**
 255  * wmi_evaluate_method - Evaluate a WMI method (deprecated)
 256  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 257  * @instance: Instance index
 258  * @method_id: Method ID to call
 259  * @in: Mandatory buffer containing input for the method call
 260  * @out: Empty buffer to return the method results
 261  *
 262  * Call an ACPI-WMI method, the caller must free @out.
 263  *
 264  * Return: acpi_status signaling success or error.
 265  */
 266 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance, u32 method_id,
 267                                 const struct acpi_buffer *in, struct acpi_buffer *out)
 268 {
 269         struct wmi_device *wdev;
 270         acpi_status status;
 271
 272         wdev = wmi_find_device_by_guid(guid_string);
 273         if (IS_ERR(wdev))
 274                 return AE_ERROR;
 275
 276         status = wmidev_evaluate_method(wdev, instance, method_id, in, out);
 277
 278         wmi_device_put(wdev);
 279
 280         return status;
 281 }
 282 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
 283
 284 /**
 285  * wmidev_evaluate_method - Evaluate a WMI method
 286  * @wdev: A wmi bus device from a driver
 287  * @instance: Instance index
 288  * @method_id: Method ID to call
 289  * @in: Mandatory buffer containing input for the method call
 290  * @out: Empty buffer to return the method results
 291  *
 292  * Call an ACPI-WMI method, the caller must free @out.
 293  *
 294  * Return: acpi_status signaling success or error.
 295  */
 296 acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 method_id,
 297                                    const struct acpi_buffer *in, struct acpi_buffer *out)
 298 {
 299         struct guid_block *block;
 300         struct wmi_block *wblock;
 301         acpi_handle handle;
 302         struct acpi_object_list input;
 303         union acpi_object params[3];
 304         char method[WMI_ACPI_METHOD_NAME_SIZE];
 305
 306         wblock = container_of(wdev, struct wmi_block, dev);
 307         block = &wblock->gblock;
 308         handle = wblock->acpi_device->handle;
 309
 310         if (!in)
 311                 return AE_BAD_DATA;
 312
 313         if (!(block->flags & ACPI_WMI_METHOD))
 314                 return AE_BAD_DATA;
 315
 316         if (block->instance_count <= instance)
 317                 return AE_BAD_PARAMETER;
 318
 319         input.count = 3;
 320         input.pointer = params;
 321
 322         params[0].type = ACPI_TYPE_INTEGER;
 323         params[0].integer.value = instance;
 324         params[1].type = ACPI_TYPE_INTEGER;
 325         params[1].integer.value = method_id;
 326         params[2].type = get_param_acpi_type(wblock);
 327         params[2].buffer.length = in->length;
 328         params[2].buffer.pointer = in->pointer;
 329
 330         get_acpi_method_name(wblock, 'M', method);
 331
 332         return acpi_evaluate_object(handle, method, &input, out);
 333 }
 334 EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
 335
 336 static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
 337                                  struct acpi_buffer *out)
 338 {
 339         struct guid_block *block;
 340         acpi_handle handle;
 341         acpi_status status, wc_status = AE_ERROR;
 342         struct acpi_object_list input;
 343         union acpi_object wq_params[1];
 344         char wc_method[WMI_ACPI_METHOD_NAME_SIZE];
 345         char method[WMI_ACPI_METHOD_NAME_SIZE];
 346
 347         if (!out)
 348                 return AE_BAD_PARAMETER;
 349
 350         block = &wblock->gblock;
 351         handle = wblock->acpi_device->handle;
 352
 353         if (block->instance_count <= instance)
 354                 return AE_BAD_PARAMETER;
 355
 356         /* Check GUID is a data block */
 357         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 358                 return AE_ERROR;
 359
 360         input.count = 1;
 361         input.pointer = wq_params;
 362         wq_params[0].type = ACPI_TYPE_INTEGER;
 363         wq_params[0].integer.value = instance;
 364
 365         if (instance == 0 && test_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags))
 366                 input.count = 0;
 367
 368         /*
 369          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
 370          * enable collection.
 371          */
 372         if (block->flags & ACPI_WMI_EXPENSIVE) {
 373                 get_acpi_method_name(wblock, 'C', wc_method);
 374
 375                 /*
 376                  * Some GUIDs break the specification by declaring themselves
 377                  * expensive, but have no corresponding WCxx method. So we
 378                  * should not fail if this happens.
 379                  */
 380                 wc_status = acpi_execute_simple_method(handle, wc_method, 1);
 381         }
 382
 383         get_acpi_method_name(wblock, 'Q', method);
 384         status = acpi_evaluate_object(handle, method, &input, out);
 385
 386         /*
 387          * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
 388          * the WQxx method failed - we should disable collection anyway.
 389          */
 390         if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
 391                 /*
 392                  * Ignore whether this WCxx call succeeds or not since
 393                  * the previously executed WQxx method call might have
 394                  * succeeded, and returning the failing status code
 395                  * of this call would throw away the result of the WQxx
 396                  * call, potentially leaking memory.
 397                  */
 398                 acpi_execute_simple_method(handle, wc_method, 0);
 399         }
 400
 401         return status;
 402 }
 403
 404 /**
 405  * wmi_query_block - Return contents of a WMI block (deprecated)
 406  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 407  * @instance: Instance index
 408  * @out: Empty buffer to return the contents of the data block to
 409  *
 410  * Query a ACPI-WMI block, the caller must free @out.
 411  *
 412  * Return: ACPI object containing the content of the WMI block.
 413  */
 414 acpi_status wmi_query_block(const char *guid_string, u8 instance,
 415                             struct acpi_buffer *out)
 416 {
 417         struct wmi_block *wblock;
 418         struct wmi_device *wdev;
 419         acpi_status status;
 420
 421         wdev = wmi_find_device_by_guid(guid_string);
 422         if (IS_ERR(wdev))
 423                 return AE_ERROR;
 424
 425         wblock = container_of(wdev, struct wmi_block, dev);
 426         status = __query_block(wblock, instance, out);
 427
 428         wmi_device_put(wdev);
 429
 430         return status;
 431 }
 432 EXPORT_SYMBOL_GPL(wmi_query_block);
 433
 434 /**
 435  * wmidev_block_query - Return contents of a WMI block
 436  * @wdev: A wmi bus device from a driver
 437  * @instance: Instance index
 438  *
 439  * Query an ACPI-WMI block, the caller must free the result.
 440  *
 441  * Return: ACPI object containing the content of the WMI block.
 442  */
 443 union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
 444 {
 445         struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
 446         struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 447
 448         if (ACPI_FAILURE(__query_block(wblock, instance, &out)))
 449                 return NULL;
 450
 451         return out.pointer;
 452 }
 453 EXPORT_SYMBOL_GPL(wmidev_block_query);
 454
 455 /**
 456  * wmi_set_block - Write to a WMI block (deprecated)
 457  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 458  * @instance: Instance index
 459  * @in: Buffer containing new values for the data block
 460  *
 461  * Write the contents of the input buffer to an ACPI-WMI data block.
 462  *
 463  * Return: acpi_status signaling success or error.
 464  */
 465 acpi_status wmi_set_block(const char *guid_string, u8 instance, const struct acpi_buffer *in)
 466 {
 467         struct wmi_device *wdev;
 468         acpi_status status;
 469
 470         wdev = wmi_find_device_by_guid(guid_string);
 471         if (IS_ERR(wdev))
 472                 return AE_ERROR;
 473
 474         status =  wmidev_block_set(wdev, instance, in);
 475         wmi_device_put(wdev);
 476
 477         return status;
 478 }
 479 EXPORT_SYMBOL_GPL(wmi_set_block);
 480
 481 /**
 482  * wmidev_block_set - Write to a WMI block
 483  * @wdev: A wmi bus device from a driver
 484  * @instance: Instance index
 485  * @in: Buffer containing new values for the data block
 486  *
 487  * Write contents of the input buffer to an ACPI-WMI data block.
 488  *
 489  * Return: acpi_status signaling success or error.
 490  */
 491 acpi_status wmidev_block_set(struct wmi_device *wdev, u8 instance, const struct acpi_buffer *in)
 492 {
 493         struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
 494         acpi_handle handle = wblock->acpi_device->handle;
 495         struct guid_block *block = &wblock->gblock;
 496         char method[WMI_ACPI_METHOD_NAME_SIZE];
 497         struct acpi_object_list input;
 498         union acpi_object params[2];
 499
 500         if (!in)
 501                 return AE_BAD_DATA;
 502
 503         if (block->instance_count <= instance)
 504                 return AE_BAD_PARAMETER;
 505
 506         /* Check GUID is a data block */
 507         if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
 508                 return AE_ERROR;
 509
 510         input.count = 2;
 511         input.pointer = params;
 512         params[0].type = ACPI_TYPE_INTEGER;
 513         params[0].integer.value = instance;
 514         params[1].type = get_param_acpi_type(wblock);
 515         params[1].buffer.length = in->length;
 516         params[1].buffer.pointer = in->pointer;
 517
 518         get_acpi_method_name(wblock, 'S', method);
 519
 520         return acpi_evaluate_object(handle, method, &input, NULL);
 521 }
 522 EXPORT_SYMBOL_GPL(wmidev_block_set);
 523
 524 /**
 525  * wmi_install_notify_handler - Register handler for WMI events (deprecated)
 526  * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 527  * @handler: Function to handle notifications
 528  * @data: Data to be returned to handler when event is fired
 529  *
 530  * Register a handler for events sent to the ACPI-WMI mapper device.
 531  *
 532  * Return: acpi_status signaling success or error.
 533  */
 534 acpi_status wmi_install_notify_handler(const char *guid,
 535                                        wmi_notify_handler handler,
 536                                        void *data)
 537 {
 538         struct wmi_block *wblock;
 539         struct wmi_device *wdev;
 540         acpi_status status;
 541
 542         wdev = wmi_find_device_by_guid(guid);
 543         if (IS_ERR(wdev))
 544                 return AE_ERROR;
 545
 546         wblock = container_of(wdev, struct wmi_block, dev);
 547
 548         down_write(&wblock->notify_lock);
 549         if (wblock->handler) {
 550                 status = AE_ALREADY_ACQUIRED;
 551         } else {
 552                 wblock->handler = handler;
 553                 wblock->handler_data = data;
 554
 555                 if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
 556                         dev_warn(&wblock->dev.dev, "Failed to enable device\n");
 557
 558                 status = AE_OK;
 559         }
 560         up_write(&wblock->notify_lock);
 561
 562         wmi_device_put(wdev);
 563
 564         return status;
 565 }
 566 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
 567
 568 /**
 569  * wmi_remove_notify_handler - Unregister handler for WMI events (deprecated)
 570  * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 571  *
 572  * Unregister handler for events sent to the ACPI-WMI mapper device.
 573  *
 574  * Return: acpi_status signaling success or error.
 575  */
 576 acpi_status wmi_remove_notify_handler(const char *guid)
 577 {
 578         struct wmi_block *wblock;
 579         struct wmi_device *wdev;
 580         acpi_status status;
 581
 582         wdev = wmi_find_device_by_guid(guid);
 583         if (IS_ERR(wdev))
 584                 return AE_ERROR;
 585
 586         wblock = container_of(wdev, struct wmi_block, dev);
 587
 588         down_write(&wblock->notify_lock);
 589         if (!wblock->handler) {
 590                 status = AE_NULL_ENTRY;
 591         } else {
 592                 if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
 593                         dev_warn(&wblock->dev.dev, "Failed to disable device\n");
 594
 595                 wblock->handler = NULL;
 596                 wblock->handler_data = NULL;
 597
 598                 status = AE_OK;
 599         }
 600         up_write(&wblock->notify_lock);
 601
 602         wmi_device_put(wdev);
 603
 604         return status;
 605 }
 606 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
 607
 608 /**
 609  * wmi_has_guid - Check if a GUID is available
 610  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 611  *
 612  * Check if a given GUID is defined by _WDG.
 613  *
 614  * Return: True if GUID is available, false otherwise.
 615  */
 616 bool wmi_has_guid(const char *guid_string)
 617 {
 618         struct wmi_device *wdev;
 619
 620         wdev = wmi_find_device_by_guid(guid_string);
 621         if (IS_ERR(wdev))
 622                 return false;
 623
 624         wmi_device_put(wdev);
 625
 626         return true;
 627 }
 628 EXPORT_SYMBOL_GPL(wmi_has_guid);
 629
 630 /**
 631  * wmi_get_acpi_device_uid() - Get _UID name of ACPI device that defines GUID (deprecated)
 632  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 633  *
 634  * Find the _UID of ACPI device associated with this WMI GUID.
 635  *
 636  * Return: The ACPI _UID field value or NULL if the WMI GUID was not found.
 637  */
 638 char *wmi_get_acpi_device_uid(const char *guid_string)
 639 {
 640         struct wmi_block *wblock;
 641         struct wmi_device *wdev;
 642         char *uid;
 643
 644         wdev = wmi_find_device_by_guid(guid_string);
 645         if (IS_ERR(wdev))
 646                 return NULL;
 647
 648         wblock = container_of(wdev, struct wmi_block, dev);
 649         uid = acpi_device_uid(wblock->acpi_device);
 650
 651         wmi_device_put(wdev);
 652
 653         return uid;
 654 }
 655 EXPORT_SYMBOL_GPL(wmi_get_acpi_device_uid);
 656
 657 #define drv_to_wdrv(__drv)      container_of_const(__drv, struct wmi_driver, driver)
 658
 659 /*
 660  * sysfs interface
 661  */
 662 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 663                              char *buf)
 664 {
 665         struct wmi_block *wblock = dev_to_wblock(dev);
 666
 667         return sysfs_emit(buf, "wmi:%pUL\n", &wblock->gblock.guid);
 668 }
 669 static DEVICE_ATTR_RO(modalias);
 670
 671 static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
 672                          char *buf)
 673 {
 674         struct wmi_block *wblock = dev_to_wblock(dev);
 675
 676         return sysfs_emit(buf, "%pUL\n", &wblock->gblock.guid);
 677 }
 678 static DEVICE_ATTR_RO(guid);
 679
 680 static ssize_t instance_count_show(struct device *dev,
 681                                    struct device_attribute *attr, char *buf)
 682 {
 683         struct wmi_block *wblock = dev_to_wblock(dev);
 684
 685         return sysfs_emit(buf, "%d\n", (int)wblock->gblock.instance_count);
 686 }
 687 static DEVICE_ATTR_RO(instance_count);
 688
 689 static ssize_t expensive_show(struct device *dev,
 690                               struct device_attribute *attr, char *buf)
 691 {
 692         struct wmi_block *wblock = dev_to_wblock(dev);
 693
 694         return sysfs_emit(buf, "%d\n",
 695                           (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
 696 }
 697 static DEVICE_ATTR_RO(expensive);
 698
 699 static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr,
 700                                     char *buf)
 701 {
 702         struct wmi_device *wdev = to_wmi_device(dev);
 703         ssize_t ret;
 704
 705         device_lock(dev);
 706         ret = sysfs_emit(buf, "%s\n", wdev->driver_override);
 707         device_unlock(dev);
 708
 709         return ret;
 710 }
 711
 712 static ssize_t driver_override_store(struct device *dev, struct device_attribute *attr,
 713                                      const char *buf, size_t count)
 714 {
 715         struct wmi_device *wdev = to_wmi_device(dev);
 716         int ret;
 717
 718         ret = driver_set_override(dev, &wdev->driver_override, buf, count);
 719         if (ret < 0)
 720                 return ret;
 721
 722         return count;
 723 }
 724 static DEVICE_ATTR_RW(driver_override);
 725
 726 static struct attribute *wmi_attrs[] = {
 727         &dev_attr_modalias.attr,
 728         &dev_attr_guid.attr,
 729         &dev_attr_instance_count.attr,
 730         &dev_attr_expensive.attr,
 731         &dev_attr_driver_override.attr,
 732         NULL
 733 };
 734 ATTRIBUTE_GROUPS(wmi);
 735
 736 static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
 737                               char *buf)
 738 {
 739         struct wmi_block *wblock = dev_to_wblock(dev);
 740
 741         return sysfs_emit(buf, "%02X\n", (unsigned int)wblock->gblock.notify_id);
 742 }
 743 static DEVICE_ATTR_RO(notify_id);
 744
 745 static struct attribute *wmi_event_attrs[] = {
 746         &dev_attr_notify_id.attr,
 747         NULL
 748 };
 749 ATTRIBUTE_GROUPS(wmi_event);
 750
 751 static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
 752                               char *buf)
 753 {
 754         struct wmi_block *wblock = dev_to_wblock(dev);
 755
 756         return sysfs_emit(buf, "%c%c\n", wblock->gblock.object_id[0],
 757                           wblock->gblock.object_id[1]);
 758 }
 759 static DEVICE_ATTR_RO(object_id);
 760
 761 static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
 762                             char *buf)
 763 {
 764         struct wmi_device *wdev = dev_to_wdev(dev);
 765
 766         return sysfs_emit(buf, "%d\n", (int)wdev->setable);
 767 }
 768 static DEVICE_ATTR_RO(setable);
 769
 770 static struct attribute *wmi_data_attrs[] = {
 771         &dev_attr_object_id.attr,
 772         &dev_attr_setable.attr,
 773         NULL
 774 };
 775 ATTRIBUTE_GROUPS(wmi_data);
 776
 777 static struct attribute *wmi_method_attrs[] = {
 778         &dev_attr_object_id.attr,
 779         NULL
 780 };
 781 ATTRIBUTE_GROUPS(wmi_method);
 782
 783 static int wmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
 784 {
 785         const struct wmi_block *wblock = dev_to_wblock(dev);
 786
 787         if (add_uevent_var(env, "MODALIAS=wmi:%pUL", &wblock->gblock.guid))
 788                 return -ENOMEM;
 789
 790         if (add_uevent_var(env, "WMI_GUID=%pUL", &wblock->gblock.guid))
 791                 return -ENOMEM;
 792
 793         return 0;
 794 }
 795
 796 static void wmi_dev_release(struct device *dev)
 797 {
 798         struct wmi_block *wblock = dev_to_wblock(dev);
 799
 800         kfree(wblock->dev.driver_override);
 801         kfree(wblock);
 802 }
 803
 804 static int wmi_dev_match(struct device *dev, const struct device_driver *driver)
 805 {
 806         const struct wmi_driver *wmi_driver = drv_to_wdrv(driver);
 807         struct wmi_block *wblock = dev_to_wblock(dev);
 808         const struct wmi_device_id *id = wmi_driver->id_table;
 809
 810         /* When driver_override is set, only bind to the matching driver */
 811         if (wblock->dev.driver_override)
 812                 return !strcmp(wblock->dev.driver_override, driver->name);
 813
 814         if (id == NULL)
 815                 return 0;
 816
 817         while (*id->guid_string) {
 818                 if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
 819                         return 1;
 820
 821                 id++;
 822         }
 823
 824         return 0;
 825 }
 826
 827 static int wmi_dev_probe(struct device *dev)
 828 {
 829         struct wmi_block *wblock = dev_to_wblock(dev);
 830         struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
 831         int ret = 0;
 832
 833         /* Some older WMI drivers will break if instantiated multiple times,
 834          * so they are blocked from probing WMI devices with a duplicated GUID.
 835          *
 836          * New WMI drivers should support being instantiated multiple times.
 837          */
 838         if (test_bit(WMI_GUID_DUPLICATED, &wblock->flags) && !wdriver->no_singleton) {
 839                 dev_warn(dev, "Legacy driver %s cannot be instantiated multiple times\n",
 840                          dev->driver->name);
 841
 842                 return -ENODEV;
 843         }
 844
 845         if (wdriver->notify) {
 846                 if (test_bit(WMI_NO_EVENT_DATA, &wblock->flags) && !wdriver->no_notify_data)
 847                         return -ENODEV;
 848         }
 849
 850         if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
 851                 dev_warn(dev, "failed to enable device -- probing anyway\n");
 852
 853         if (wdriver->probe) {
 854                 ret = wdriver->probe(dev_to_wdev(dev),
 855                                 find_guid_context(wblock, wdriver));
 856                 if (ret) {
 857                         if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
 858                                 dev_warn(dev, "Failed to disable device\n");
 859
 860                         return ret;
 861                 }
 862         }
 863
 864         down_write(&wblock->notify_lock);
 865         wblock->driver_ready = true;
 866         up_write(&wblock->notify_lock);
 867
 868         return 0;
 869 }
 870
 871 static void wmi_dev_remove(struct device *dev)
 872 {
 873         struct wmi_block *wblock = dev_to_wblock(dev);
 874         struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
 875
 876         down_write(&wblock->notify_lock);
 877         wblock->driver_ready = false;
 878         up_write(&wblock->notify_lock);
 879
 880         if (wdriver->remove)
 881                 wdriver->remove(dev_to_wdev(dev));
 882
 883         if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
 884                 dev_warn(dev, "failed to disable device\n");
 885 }
 886
 887 static struct class wmi_bus_class = {
 888         .name = "wmi_bus",
 889 };
 890
 891 static const struct bus_type wmi_bus_type = {
 892         .name = "wmi",
 893         .dev_groups = wmi_groups,
 894         .match = wmi_dev_match,
 895         .uevent = wmi_dev_uevent,
 896         .probe = wmi_dev_probe,
 897         .remove = wmi_dev_remove,
 898 };
 899
 900 static const struct device_type wmi_type_event = {
 901         .name = "event",
 902         .groups = wmi_event_groups,
 903         .release = wmi_dev_release,
 904 };
 905
 906 static const struct device_type wmi_type_method = {
 907         .name = "method",
 908         .groups = wmi_method_groups,
 909         .release = wmi_dev_release,
 910 };
 911
 912 static const struct device_type wmi_type_data = {
 913         .name = "data",
 914         .groups = wmi_data_groups,
 915         .release = wmi_dev_release,
 916 };
 917
 918 /*
 919  * _WDG is a static list that is only parsed at startup,
 920  * so it's safe to count entries without extra protection.
 921  */
 922 static int guid_count(const guid_t *guid)
 923 {
 924         struct wmi_block *wblock;
 925         int count = 0;
 926
 927         list_for_each_entry(wblock, &wmi_block_list, list) {
 928                 if (guid_equal(&wblock->gblock.guid, guid))
 929                         count++;
 930         }
 931
 932         return count;
 933 }
 934
 935 static int wmi_create_device(struct device *wmi_bus_dev,
 936                              struct wmi_block *wblock,
 937                              struct acpi_device *device)
 938 {
 939         char method[WMI_ACPI_METHOD_NAME_SIZE];
 940         struct acpi_device_info *info;
 941         acpi_handle method_handle;
 942         acpi_status status;
 943         uint count;
 944
 945         if (wblock->gblock.flags & ACPI_WMI_EVENT) {
 946                 wblock->dev.dev.type = &wmi_type_event;
 947                 goto out_init;
 948         }
 949
 950         if (wblock->gblock.flags & ACPI_WMI_METHOD) {
 951                 get_acpi_method_name(wblock, 'M', method);
 952                 if (!acpi_has_method(device->handle, method)) {
 953                         dev_warn(wmi_bus_dev,
 954                                  FW_BUG "%s method block execution control method not found\n",
 955                                  method);
 956
 957                         return -ENXIO;
 958                 }
 959
 960                 wblock->dev.dev.type = &wmi_type_method;
 961                 goto out_init;
 962         }
 963
 964         /*
 965          * Data Block Query Control Method (WQxx by convention) is
 966          * required per the WMI documentation. If it is not present,
 967          * we ignore this data block.
 968          */
 969         get_acpi_method_name(wblock, 'Q', method);
 970         status = acpi_get_handle(device->handle, method, &method_handle);
 971         if (ACPI_FAILURE(status)) {
 972                 dev_warn(wmi_bus_dev,
 973                          FW_BUG "%s data block query control method not found\n",
 974                          method);
 975
 976                 return -ENXIO;
 977         }
 978
 979         status = acpi_get_object_info(method_handle, &info);
 980         if (ACPI_FAILURE(status))
 981                 return -EIO;
 982
 983         wblock->dev.dev.type = &wmi_type_data;
 984
 985         /*
 986          * The Microsoft documentation specifically states:
 987          *
 988          *   Data blocks registered with only a single instance
 989          *   can ignore the parameter.
 990          *
 991          * ACPICA will get mad at us if we call the method with the wrong number
 992          * of arguments, so check what our method expects.  (On some Dell
 993          * laptops, WQxx may not be a method at all.)
 994          */
 995         if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
 996                 set_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags);
 997
 998         kfree(info);
 999
1000         get_acpi_method_name(wblock, 'S', method);
1001         if (acpi_has_method(device->handle, method))
1002                 wblock->dev.setable = true;
1003
1004  out_init:
1005         init_rwsem(&wblock->notify_lock);
1006         wblock->driver_ready = false;
1007         wblock->dev.dev.bus = &wmi_bus_type;
1008         wblock->dev.dev.parent = wmi_bus_dev;
1009
1010         count = guid_count(&wblock->gblock.guid);
1011         if (count) {
1012                 dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, count);
1013                 set_bit(WMI_GUID_DUPLICATED, &wblock->flags);
1014         } else {
1015                 dev_set_name(&wblock->dev.dev, "%pUL", &wblock->gblock.guid);
1016         }
1017
1018         device_initialize(&wblock->dev.dev);
1019
1020         return 0;
1021 }
1022
1023 static int wmi_add_device(struct platform_device *pdev, struct wmi_device *wdev)
1024 {
1025         struct device_link *link;
1026
1027         /*
1028          * Many aggregate WMI drivers do not use -EPROBE_DEFER when they
1029          * are unable to find a WMI device during probe, instead they require
1030          * all WMI devices associated with an platform device to become available
1031          * at once. This device link thus prevents WMI drivers from probing until
1032          * the associated platform device has finished probing (and has registered
1033          * all discovered WMI devices).
1034          */
1035
1036         link = device_link_add(&wdev->dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
1037         if (!link)
1038                 return -EINVAL;
1039
1040         return device_add(&wdev->dev);
1041 }
1042
1043 /*
1044  * Parse the _WDG method for the GUID data blocks
1045  */
1046 static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
1047 {
1048         struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
1049         struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
1050         const struct guid_block *gblock;
1051         bool event_data_available;
1052         struct wmi_block *wblock;
1053         union acpi_object *obj;
1054         acpi_status status;
1055         u32 i, total;
1056         int retval;
1057
1058         status = acpi_evaluate_object(device->handle, "_WDG", NULL, &out);
1059         if (ACPI_FAILURE(status))
1060                 return -ENXIO;
1061
1062         obj = out.pointer;
1063         if (!obj)
1064                 return -ENXIO;
1065
1066         if (obj->type != ACPI_TYPE_BUFFER) {
1067                 kfree(obj);
1068                 return -ENXIO;
1069         }
1070
1071         event_data_available = acpi_has_method(device->handle, "_WED");
1072         gblock = (const struct guid_block *)obj->buffer.pointer;
1073         total = obj->buffer.length / sizeof(struct guid_block);
1074
1075         for (i = 0; i < total; i++) {
1076                 if (!gblock[i].instance_count) {
1077                         dev_info(wmi_bus_dev, FW_INFO "%pUL has zero instances\n", &gblock[i].guid);
1078                         continue;
1079                 }
1080
1081                 wblock = kzalloc(sizeof(*wblock), GFP_KERNEL);
1082                 if (!wblock)
1083                         continue;
1084
1085                 wblock->acpi_device = device;
1086                 wblock->gblock = gblock[i];
1087                 if (gblock[i].flags & ACPI_WMI_EVENT && !event_data_available)
1088                         set_bit(WMI_NO_EVENT_DATA, &wblock->flags);
1089
1090                 retval = wmi_create_device(wmi_bus_dev, wblock, device);
1091                 if (retval) {
1092                         kfree(wblock);
1093                         continue;
1094                 }
1095
1096                 list_add_tail(&wblock->list, &wmi_block_list);
1097
1098                 retval = wmi_add_device(pdev, &wblock->dev);
1099                 if (retval) {
1100                         dev_err(wmi_bus_dev, "failed to register %pUL\n",
1101                                 &wblock->gblock.guid);
1102
1103                         list_del(&wblock->list);
1104                         put_device(&wblock->dev.dev);
1105                 }
1106         }
1107
1108         kfree(obj);
1109
1110         return 0;
1111 }
1112
1113 static int wmi_get_notify_data(struct wmi_block *wblock, union acpi_object **obj)
1114 {
1115         struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
1116         union acpi_object param = {
1117                 .integer = {
1118                         .type = ACPI_TYPE_INTEGER,
1119                         .value = wblock->gblock.notify_id,
1120                 }
1121         };
1122         struct acpi_object_list input = {
1123                 .count = 1,
1124                 .pointer = &param,
1125         };
1126         acpi_status status;
1127
1128         status = acpi_evaluate_object(wblock->acpi_device->handle, "_WED", &input, &data);
1129         if (ACPI_FAILURE(status)) {
1130                 dev_warn(&wblock->dev.dev, "Failed to get event data\n");
1131                 return -EIO;
1132         }
1133
1134         *obj = data.pointer;
1135
1136         return 0;
1137 }
1138
1139 static void wmi_notify_driver(struct wmi_block *wblock, union acpi_object *obj)
1140 {
1141         struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
1142
1143         if (!obj && !driver->no_notify_data) {
1144                 dev_warn(&wblock->dev.dev, "Event contains no event data\n");
1145                 return;
1146         }
1147
1148         if (driver->notify)
1149                 driver->notify(&wblock->dev, obj);
1150 }
1151
1152 static int wmi_notify_device(struct device *dev, void *data)
1153 {
1154         struct wmi_block *wblock = dev_to_wblock(dev);
1155         union acpi_object *obj = NULL;
1156         u32 *event = data;
1157         int ret;
1158
1159         if (!(wblock->gblock.flags & ACPI_WMI_EVENT && wblock->gblock.notify_id == *event))
1160                 return 0;
1161
1162         /* The ACPI WMI specification says that _WED should be
1163          * evaluated every time an notification is received, even
1164          * if no consumers are present.
1165          *
1166          * Some firmware implementations actually depend on this
1167          * by using a queue for events which will fill up if the
1168          * WMI driver core stops evaluating _WED due to missing
1169          * WMI event consumers.
1170          */
1171         if (!test_bit(WMI_NO_EVENT_DATA, &wblock->flags)) {
1172                 ret = wmi_get_notify_data(wblock, &obj);
1173                 if (ret < 0)
1174                         return -EIO;
1175         }
1176
1177         down_read(&wblock->notify_lock);
1178
1179         if (wblock->dev.dev.driver && wblock->driver_ready)
1180                 wmi_notify_driver(wblock, obj);
1181
1182         if (wblock->handler)
1183                 wblock->handler(obj, wblock->handler_data);
1184
1185         up_read(&wblock->notify_lock);
1186
1187         kfree(obj);
1188
1189         acpi_bus_generate_netlink_event("wmi", acpi_dev_name(wblock->acpi_device), *event, 0);
1190
1191         return -EBUSY;
1192 }
1193
1194 static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, void *context)
1195 {
1196         struct device *wmi_bus_dev = context;
1197
1198         device_for_each_child(wmi_bus_dev, &event, wmi_notify_device);
1199 }
1200
1201 static int wmi_remove_device(struct device *dev, void *data)
1202 {
1203         struct wmi_block *wblock = dev_to_wblock(dev);
1204
1205         list_del(&wblock->list);
1206         device_unregister(dev);
1207
1208         return 0;
1209 }
1210
1211 static void acpi_wmi_remove(struct platform_device *device)
1212 {
1213         struct device *wmi_bus_device = dev_get_drvdata(&device->dev);
1214
1215         device_for_each_child_reverse(wmi_bus_device, NULL, wmi_remove_device);
1216 }
1217
1218 static void acpi_wmi_remove_notify_handler(void *data)
1219 {
1220         struct acpi_device *acpi_device = data;
1221
1222         acpi_remove_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY, acpi_wmi_notify_handler);
1223 }
1224
1225 static void acpi_wmi_remove_bus_device(void *data)
1226 {
1227         struct device *wmi_bus_dev = data;
1228
1229         device_unregister(wmi_bus_dev);
1230 }
1231
1232 static int acpi_wmi_probe(struct platform_device *device)
1233 {
1234         struct acpi_device *acpi_device;
1235         struct device *wmi_bus_dev;
1236         acpi_status status;
1237         int error;
1238
1239         acpi_device = ACPI_COMPANION(&device->dev);
1240         if (!acpi_device) {
1241                 dev_err(&device->dev, "ACPI companion is missing\n");
1242                 return -ENODEV;
1243         }
1244
1245         wmi_bus_dev = device_create(&wmi_bus_class, &device->dev, MKDEV(0, 0), NULL, "wmi_bus-%s",
1246                                     dev_name(&device->dev));
1247         if (IS_ERR(wmi_bus_dev))
1248                 return PTR_ERR(wmi_bus_dev);
1249
1250         error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_bus_device, wmi_bus_dev);
1251         if (error < 0)
1252                 return error;
1253
1254         dev_set_drvdata(&device->dev, wmi_bus_dev);
1255
1256         status = acpi_install_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY,
1257                                              acpi_wmi_notify_handler, wmi_bus_dev);
1258         if (ACPI_FAILURE(status)) {
1259                 dev_err(&device->dev, "Error installing notify handler\n");
1260                 return -ENODEV;
1261         }
1262         error = devm_add_action_or_reset(&device->dev, acpi_wmi_remove_notify_handler,
1263                                          acpi_device);
1264         if (error < 0)
1265                 return error;
1266
1267         error = parse_wdg(wmi_bus_dev, device);
1268         if (error) {
1269                 dev_err(&device->dev, "Failed to parse _WDG method\n");
1270                 return error;
1271         }
1272
1273         return 0;
1274 }
1275
1276 int __must_check __wmi_driver_register(struct wmi_driver *driver,
1277                                        struct module *owner)
1278 {
1279         driver->driver.owner = owner;
1280         driver->driver.bus = &wmi_bus_type;
1281
1282         return driver_register(&driver->driver);
1283 }
1284 EXPORT_SYMBOL(__wmi_driver_register);
1285
1286 /**
1287  * wmi_driver_unregister() - Unregister a WMI driver
1288  * @driver: WMI driver to unregister
1289  *
1290  * Unregisters a WMI driver from the WMI bus.
1291  */
1292 void wmi_driver_unregister(struct wmi_driver *driver)
1293 {
1294         driver_unregister(&driver->driver);
1295 }
1296 EXPORT_SYMBOL(wmi_driver_unregister);
1297
1298 static struct platform_driver acpi_wmi_driver = {
1299         .driver = {
1300                 .name = "acpi-wmi",
1301                 .acpi_match_table = wmi_device_ids,
1302         },
1303         .probe = acpi_wmi_probe,
1304         .remove_new = acpi_wmi_remove,
1305 };
1306
1307 static int __init acpi_wmi_init(void)
1308 {
1309         int error;
1310
1311         if (acpi_disabled)
1312                 return -ENODEV;
1313
1314         error = class_register(&wmi_bus_class);
1315         if (error)
1316                 return error;
1317
1318         error = bus_register(&wmi_bus_type);
1319         if (error)
1320                 goto err_unreg_class;
1321
1322         error = platform_driver_register(&acpi_wmi_driver);
1323         if (error) {
1324                 pr_err("Error loading mapper\n");
1325                 goto err_unreg_bus;
1326         }
1327
1328         return 0;
1329
1330 err_unreg_bus:
1331         bus_unregister(&wmi_bus_type);
1332
1333 err_unreg_class:
1334         class_unregister(&wmi_bus_class);
1335
1336         return error;
1337 }
1338
1339 static void __exit acpi_wmi_exit(void)
1340 {
1341         platform_driver_unregister(&acpi_wmi_driver);
1342         bus_unregister(&wmi_bus_type);
1343         class_unregister(&wmi_bus_class);
1344 }
1345
1346 subsys_initcall_sync(acpi_wmi_init);
1347 module_exit(acpi_wmi_exit);