xref: /linux/drivers/platform/x86/wmi.c (revision 5027ec19f1049a07df5b0a37b1f462514cf2724b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ACPI-WMI mapping driver
4  *
5  *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
6  *
7  *  GUID parsing code from ldm.c is:
8  *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
9  *   Copyright (c) 2001-2007 Anton Altaparmakov
10  *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
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/miscdevice.h>
27 #include <linux/module.h>
28 #include <linux/platform_device.h>
29 #include <linux/slab.h>
30 #include <linux/sysfs.h>
31 #include <linux/types.h>
32 #include <linux/uaccess.h>
33 #include <linux/uuid.h>
34 #include <linux/wmi.h>
35 #include <linux/fs.h>
36 #include <uapi/linux/wmi.h>
37 
38 MODULE_AUTHOR("Carlos Corbacho");
39 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
40 MODULE_LICENSE("GPL");
41 
42 static LIST_HEAD(wmi_block_list);
43 
44 struct guid_block {
45 	guid_t guid;
46 	union {
47 		char object_id[2];
48 		struct {
49 			unsigned char notify_id;
50 			unsigned char reserved;
51 		};
52 	};
53 	u8 instance_count;
54 	u8 flags;
55 } __packed;
56 static_assert(sizeof(typeof_member(struct guid_block, guid)) == 16);
57 static_assert(sizeof(struct guid_block) == 20);
58 static_assert(__alignof__(struct guid_block) == 1);
59 
60 enum {	/* wmi_block flags */
61 	WMI_READ_TAKES_NO_ARGS,
62 	WMI_PROBED,
63 };
64 
65 struct wmi_block {
66 	struct wmi_device dev;
67 	struct list_head list;
68 	struct guid_block gblock;
69 	struct miscdevice char_dev;
70 	struct mutex char_mutex;
71 	struct acpi_device *acpi_device;
72 	wmi_notify_handler handler;
73 	void *handler_data;
74 	u64 req_buf_size;
75 	unsigned long flags;
76 };
77 
78 
79 /*
80  * If the GUID data block is marked as expensive, we must enable and
81  * explicitily disable data collection.
82  */
83 #define ACPI_WMI_EXPENSIVE   BIT(0)
84 #define ACPI_WMI_METHOD      BIT(1)	/* GUID is a method */
85 #define ACPI_WMI_STRING      BIT(2)	/* GUID takes & returns a string */
86 #define ACPI_WMI_EVENT       BIT(3)	/* GUID is an event */
87 
88 static bool debug_event;
89 module_param(debug_event, bool, 0444);
90 MODULE_PARM_DESC(debug_event,
91 		 "Log WMI Events [0/1]");
92 
93 static bool debug_dump_wdg;
94 module_param(debug_dump_wdg, bool, 0444);
95 MODULE_PARM_DESC(debug_dump_wdg,
96 		 "Dump available WMI interfaces [0/1]");
97 
98 static const struct acpi_device_id wmi_device_ids[] = {
99 	{"PNP0C14", 0},
100 	{"pnp0c14", 0},
101 	{ }
102 };
103 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
104 
105 /* allow duplicate GUIDs as these device drivers use struct wmi_driver */
106 static const char * const allow_duplicates[] = {
107 	"05901221-D566-11D1-B2F0-00A0C9062910",	/* wmi-bmof */
108 	"8A42EA14-4F2A-FD45-6422-0087F7A7E608",	/* dell-wmi-ddv */
109 	NULL
110 };
111 
112 #define dev_to_wblock(__dev)	container_of_const(__dev, struct wmi_block, dev.dev)
113 #define dev_to_wdev(__dev)	container_of_const(__dev, struct wmi_device, dev)
114 
115 /*
116  * GUID parsing functions
117  */
118 
119 static bool guid_parse_and_compare(const char *string, const guid_t *guid)
120 {
121 	guid_t guid_input;
122 
123 	if (guid_parse(string, &guid_input))
124 		return false;
125 
126 	return guid_equal(&guid_input, guid);
127 }
128 
129 static const void *find_guid_context(struct wmi_block *wblock,
130 				     struct wmi_driver *wdriver)
131 {
132 	const struct wmi_device_id *id;
133 
134 	id = wdriver->id_table;
135 	if (!id)
136 		return NULL;
137 
138 	while (*id->guid_string) {
139 		if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
140 			return id->context;
141 		id++;
142 	}
143 	return NULL;
144 }
145 
146 static int get_subobj_info(acpi_handle handle, const char *pathname,
147 			   struct acpi_device_info **info)
148 {
149 	struct acpi_device_info *dummy_info, **info_ptr;
150 	acpi_handle subobj_handle;
151 	acpi_status status;
152 
153 	status = acpi_get_handle(handle, (char *)pathname, &subobj_handle);
154 	if (status == AE_NOT_FOUND)
155 		return -ENOENT;
156 	else if (ACPI_FAILURE(status))
157 		return -EIO;
158 
159 	info_ptr = info ? info : &dummy_info;
160 	status = acpi_get_object_info(subobj_handle, info_ptr);
161 	if (ACPI_FAILURE(status))
162 		return -EIO;
163 
164 	if (!info)
165 		kfree(dummy_info);
166 
167 	return 0;
168 }
169 
170 static acpi_status wmi_method_enable(struct wmi_block *wblock, bool enable)
171 {
172 	struct guid_block *block;
173 	char method[5];
174 	acpi_status status;
175 	acpi_handle handle;
176 
177 	block = &wblock->gblock;
178 	handle = wblock->acpi_device->handle;
179 
180 	snprintf(method, 5, "WE%02X", block->notify_id);
181 	status = acpi_execute_simple_method(handle, method, enable);
182 	if (status == AE_NOT_FOUND)
183 		return AE_OK;
184 
185 	return status;
186 }
187 
188 #define WMI_ACPI_METHOD_NAME_SIZE 5
189 
190 static inline void get_acpi_method_name(const struct wmi_block *wblock,
191 					const char method,
192 					char buffer[static WMI_ACPI_METHOD_NAME_SIZE])
193 {
194 	static_assert(ARRAY_SIZE(wblock->gblock.object_id) == 2);
195 	static_assert(WMI_ACPI_METHOD_NAME_SIZE >= 5);
196 
197 	buffer[0] = 'W';
198 	buffer[1] = method;
199 	buffer[2] = wblock->gblock.object_id[0];
200 	buffer[3] = wblock->gblock.object_id[1];
201 	buffer[4] = '\0';
202 }
203 
204 static inline acpi_object_type get_param_acpi_type(const struct wmi_block *wblock)
205 {
206 	if (wblock->gblock.flags & ACPI_WMI_STRING)
207 		return ACPI_TYPE_STRING;
208 	else
209 		return ACPI_TYPE_BUFFER;
210 }
211 
212 static acpi_status get_event_data(const struct wmi_block *wblock, struct acpi_buffer *out)
213 {
214 	union acpi_object param = {
215 		.integer = {
216 			.type = ACPI_TYPE_INTEGER,
217 			.value = wblock->gblock.notify_id,
218 		}
219 	};
220 	struct acpi_object_list input = {
221 		.count = 1,
222 		.pointer = &param,
223 	};
224 
225 	return acpi_evaluate_object(wblock->acpi_device->handle, "_WED", &input, out);
226 }
227 
228 static int wmidev_match_guid(struct device *dev, const void *data)
229 {
230 	struct wmi_block *wblock = dev_to_wblock(dev);
231 	const guid_t *guid = data;
232 
233 	if (guid_equal(guid, &wblock->gblock.guid))
234 		return 1;
235 
236 	return 0;
237 }
238 
239 static struct bus_type wmi_bus_type;
240 
241 static struct wmi_device *wmi_find_device_by_guid(const char *guid_string)
242 {
243 	struct device *dev;
244 	guid_t guid;
245 	int ret;
246 
247 	ret = guid_parse(guid_string, &guid);
248 	if (ret < 0)
249 		return ERR_PTR(ret);
250 
251 	dev = bus_find_device(&wmi_bus_type, NULL, &guid, wmidev_match_guid);
252 	if (!dev)
253 		return ERR_PTR(-ENODEV);
254 
255 	return dev_to_wdev(dev);
256 }
257 
258 static void wmi_device_put(struct wmi_device *wdev)
259 {
260 	put_device(&wdev->dev);
261 }
262 
263 /*
264  * Exported WMI functions
265  */
266 
267 /**
268  * set_required_buffer_size - Sets the buffer size needed for performing IOCTL
269  * @wdev: A wmi bus device from a driver
270  * @length: Required buffer size
271  *
272  * Allocates memory needed for buffer, stores the buffer size in that memory.
273  *
274  * Return: 0 on success or a negative error code for failure.
275  */
276 int set_required_buffer_size(struct wmi_device *wdev, u64 length)
277 {
278 	struct wmi_block *wblock;
279 
280 	wblock = container_of(wdev, struct wmi_block, dev);
281 	wblock->req_buf_size = length;
282 
283 	return 0;
284 }
285 EXPORT_SYMBOL_GPL(set_required_buffer_size);
286 
287 /**
288  * wmi_instance_count - Get number of WMI object instances
289  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
290  *
291  * Get the number of WMI object instances.
292  *
293  * Returns: Number of WMI object instances or negative error code.
294  */
295 int wmi_instance_count(const char *guid_string)
296 {
297 	struct wmi_device *wdev;
298 	int ret;
299 
300 	wdev = wmi_find_device_by_guid(guid_string);
301 	if (IS_ERR(wdev))
302 		return PTR_ERR(wdev);
303 
304 	ret = wmidev_instance_count(wdev);
305 	wmi_device_put(wdev);
306 
307 	return ret;
308 }
309 EXPORT_SYMBOL_GPL(wmi_instance_count);
310 
311 /**
312  * wmidev_instance_count - Get number of WMI object instances
313  * @wdev: A wmi bus device from a driver
314  *
315  * Get the number of WMI object instances.
316  *
317  * Returns: Number of WMI object instances.
318  */
319 u8 wmidev_instance_count(struct wmi_device *wdev)
320 {
321 	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
322 
323 	return wblock->gblock.instance_count;
324 }
325 EXPORT_SYMBOL_GPL(wmidev_instance_count);
326 
327 /**
328  * wmi_evaluate_method - Evaluate a WMI method (deprecated)
329  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
330  * @instance: Instance index
331  * @method_id: Method ID to call
332  * @in: Buffer containing input for the method call
333  * @out: Empty buffer to return the method results
334  *
335  * Call an ACPI-WMI method, the caller must free @out.
336  *
337  * Return: acpi_status signaling success or error.
338  */
339 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance, u32 method_id,
340 				const struct acpi_buffer *in, struct acpi_buffer *out)
341 {
342 	struct wmi_device *wdev;
343 	acpi_status status;
344 
345 	wdev = wmi_find_device_by_guid(guid_string);
346 	if (IS_ERR(wdev))
347 		return AE_ERROR;
348 
349 	status = wmidev_evaluate_method(wdev, instance, method_id, in, out);
350 
351 	wmi_device_put(wdev);
352 
353 	return status;
354 }
355 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
356 
357 /**
358  * wmidev_evaluate_method - Evaluate a WMI method
359  * @wdev: A wmi bus device from a driver
360  * @instance: Instance index
361  * @method_id: Method ID to call
362  * @in: Buffer containing input for the method call
363  * @out: Empty buffer to return the method results
364  *
365  * Call an ACPI-WMI method, the caller must free @out.
366  *
367  * Return: acpi_status signaling success or error.
368  */
369 acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 method_id,
370 				   const struct acpi_buffer *in, struct acpi_buffer *out)
371 {
372 	struct guid_block *block;
373 	struct wmi_block *wblock;
374 	acpi_handle handle;
375 	struct acpi_object_list input;
376 	union acpi_object params[3];
377 	char method[WMI_ACPI_METHOD_NAME_SIZE];
378 
379 	wblock = container_of(wdev, struct wmi_block, dev);
380 	block = &wblock->gblock;
381 	handle = wblock->acpi_device->handle;
382 
383 	if (!(block->flags & ACPI_WMI_METHOD))
384 		return AE_BAD_DATA;
385 
386 	if (block->instance_count <= instance)
387 		return AE_BAD_PARAMETER;
388 
389 	input.count = 2;
390 	input.pointer = params;
391 	params[0].type = ACPI_TYPE_INTEGER;
392 	params[0].integer.value = instance;
393 	params[1].type = ACPI_TYPE_INTEGER;
394 	params[1].integer.value = method_id;
395 
396 	if (in) {
397 		input.count = 3;
398 
399 		params[2].type = get_param_acpi_type(wblock);
400 		params[2].buffer.length = in->length;
401 		params[2].buffer.pointer = in->pointer;
402 	}
403 
404 	get_acpi_method_name(wblock, 'M', method);
405 
406 	return acpi_evaluate_object(handle, method, &input, out);
407 }
408 EXPORT_SYMBOL_GPL(wmidev_evaluate_method);
409 
410 static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
411 				 struct acpi_buffer *out)
412 {
413 	struct guid_block *block;
414 	acpi_handle handle;
415 	acpi_status status, wc_status = AE_ERROR;
416 	struct acpi_object_list input;
417 	union acpi_object wq_params[1];
418 	char wc_method[WMI_ACPI_METHOD_NAME_SIZE];
419 	char method[WMI_ACPI_METHOD_NAME_SIZE];
420 
421 	if (!out)
422 		return AE_BAD_PARAMETER;
423 
424 	block = &wblock->gblock;
425 	handle = wblock->acpi_device->handle;
426 
427 	if (block->instance_count <= instance)
428 		return AE_BAD_PARAMETER;
429 
430 	/* Check GUID is a data block */
431 	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
432 		return AE_ERROR;
433 
434 	input.count = 1;
435 	input.pointer = wq_params;
436 	wq_params[0].type = ACPI_TYPE_INTEGER;
437 	wq_params[0].integer.value = instance;
438 
439 	if (instance == 0 && test_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags))
440 		input.count = 0;
441 
442 	/*
443 	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
444 	 * enable collection.
445 	 */
446 	if (block->flags & ACPI_WMI_EXPENSIVE) {
447 		get_acpi_method_name(wblock, 'C', wc_method);
448 
449 		/*
450 		 * Some GUIDs break the specification by declaring themselves
451 		 * expensive, but have no corresponding WCxx method. So we
452 		 * should not fail if this happens.
453 		 */
454 		wc_status = acpi_execute_simple_method(handle, wc_method, 1);
455 	}
456 
457 	get_acpi_method_name(wblock, 'Q', method);
458 	status = acpi_evaluate_object(handle, method, &input, out);
459 
460 	/*
461 	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
462 	 * the WQxx method failed - we should disable collection anyway.
463 	 */
464 	if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
465 		/*
466 		 * Ignore whether this WCxx call succeeds or not since
467 		 * the previously executed WQxx method call might have
468 		 * succeeded, and returning the failing status code
469 		 * of this call would throw away the result of the WQxx
470 		 * call, potentially leaking memory.
471 		 */
472 		acpi_execute_simple_method(handle, wc_method, 0);
473 	}
474 
475 	return status;
476 }
477 
478 /**
479  * wmi_query_block - Return contents of a WMI block (deprecated)
480  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
481  * @instance: Instance index
482  * @out: Empty buffer to return the contents of the data block to
483  *
484  * Query a ACPI-WMI block, the caller must free @out.
485  *
486  * Return: ACPI object containing the content of the WMI block.
487  */
488 acpi_status wmi_query_block(const char *guid_string, u8 instance,
489 			    struct acpi_buffer *out)
490 {
491 	struct wmi_block *wblock;
492 	struct wmi_device *wdev;
493 	acpi_status status;
494 
495 	wdev = wmi_find_device_by_guid(guid_string);
496 	if (IS_ERR(wdev))
497 		return AE_ERROR;
498 
499 	wblock = container_of(wdev, struct wmi_block, dev);
500 	status = __query_block(wblock, instance, out);
501 
502 	wmi_device_put(wdev);
503 
504 	return status;
505 }
506 EXPORT_SYMBOL_GPL(wmi_query_block);
507 
508 /**
509  * wmidev_block_query - Return contents of a WMI block
510  * @wdev: A wmi bus device from a driver
511  * @instance: Instance index
512  *
513  * Query an ACPI-WMI block, the caller must free the result.
514  *
515  * Return: ACPI object containing the content of the WMI block.
516  */
517 union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
518 {
519 	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
520 	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
521 
522 	if (ACPI_FAILURE(__query_block(wblock, instance, &out)))
523 		return NULL;
524 
525 	return out.pointer;
526 }
527 EXPORT_SYMBOL_GPL(wmidev_block_query);
528 
529 /**
530  * wmi_set_block - Write to a WMI block (deprecated)
531  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
532  * @instance: Instance index
533  * @in: Buffer containing new values for the data block
534  *
535  * Write the contents of the input buffer to an ACPI-WMI data block.
536  *
537  * Return: acpi_status signaling success or error.
538  */
539 acpi_status wmi_set_block(const char *guid_string, u8 instance,
540 			  const struct acpi_buffer *in)
541 {
542 	struct wmi_block *wblock;
543 	struct guid_block *block;
544 	struct wmi_device *wdev;
545 	acpi_handle handle;
546 	struct acpi_object_list input;
547 	union acpi_object params[2];
548 	char method[WMI_ACPI_METHOD_NAME_SIZE];
549 	acpi_status status;
550 
551 	if (!in)
552 		return AE_BAD_DATA;
553 
554 	wdev = wmi_find_device_by_guid(guid_string);
555 	if (IS_ERR(wdev))
556 		return AE_ERROR;
557 
558 	wblock = container_of(wdev, struct wmi_block, dev);
559 	block = &wblock->gblock;
560 	handle = wblock->acpi_device->handle;
561 
562 	if (block->instance_count <= instance) {
563 		status = AE_BAD_PARAMETER;
564 
565 		goto err_wdev_put;
566 	}
567 
568 	/* Check GUID is a data block */
569 	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD)) {
570 		status = AE_ERROR;
571 
572 		goto err_wdev_put;
573 	}
574 
575 	input.count = 2;
576 	input.pointer = params;
577 	params[0].type = ACPI_TYPE_INTEGER;
578 	params[0].integer.value = instance;
579 	params[1].type = get_param_acpi_type(wblock);
580 	params[1].buffer.length = in->length;
581 	params[1].buffer.pointer = in->pointer;
582 
583 	get_acpi_method_name(wblock, 'S', method);
584 
585 	status = acpi_evaluate_object(handle, method, &input, NULL);
586 
587 err_wdev_put:
588 	wmi_device_put(wdev);
589 
590 	return status;
591 }
592 EXPORT_SYMBOL_GPL(wmi_set_block);
593 
594 static void wmi_dump_wdg(const struct guid_block *g)
595 {
596 	pr_info("%pUL:\n", &g->guid);
597 	if (g->flags & ACPI_WMI_EVENT)
598 		pr_info("\tnotify_id: 0x%02X\n", g->notify_id);
599 	else
600 		pr_info("\tobject_id: %2pE\n", g->object_id);
601 	pr_info("\tinstance_count: %d\n", g->instance_count);
602 	pr_info("\tflags: %#x", g->flags);
603 	if (g->flags) {
604 		if (g->flags & ACPI_WMI_EXPENSIVE)
605 			pr_cont(" ACPI_WMI_EXPENSIVE");
606 		if (g->flags & ACPI_WMI_METHOD)
607 			pr_cont(" ACPI_WMI_METHOD");
608 		if (g->flags & ACPI_WMI_STRING)
609 			pr_cont(" ACPI_WMI_STRING");
610 		if (g->flags & ACPI_WMI_EVENT)
611 			pr_cont(" ACPI_WMI_EVENT");
612 	}
613 	pr_cont("\n");
614 
615 }
616 
617 static void wmi_notify_debug(u32 value, void *context)
618 {
619 	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
620 	union acpi_object *obj;
621 	acpi_status status;
622 
623 	status = wmi_get_event_data(value, &response);
624 	if (status != AE_OK) {
625 		pr_info("bad event status 0x%x\n", status);
626 		return;
627 	}
628 
629 	obj = response.pointer;
630 	if (!obj)
631 		return;
632 
633 	pr_info("DEBUG: event 0x%02X ", value);
634 	switch (obj->type) {
635 	case ACPI_TYPE_BUFFER:
636 		pr_cont("BUFFER_TYPE - length %u\n", obj->buffer.length);
637 		break;
638 	case ACPI_TYPE_STRING:
639 		pr_cont("STRING_TYPE - %s\n", obj->string.pointer);
640 		break;
641 	case ACPI_TYPE_INTEGER:
642 		pr_cont("INTEGER_TYPE - %llu\n", obj->integer.value);
643 		break;
644 	case ACPI_TYPE_PACKAGE:
645 		pr_cont("PACKAGE_TYPE - %u elements\n", obj->package.count);
646 		break;
647 	default:
648 		pr_cont("object type 0x%X\n", obj->type);
649 	}
650 	kfree(obj);
651 }
652 
653 /**
654  * wmi_install_notify_handler - Register handler for WMI events (deprecated)
655  * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
656  * @handler: Function to handle notifications
657  * @data: Data to be returned to handler when event is fired
658  *
659  * Register a handler for events sent to the ACPI-WMI mapper device.
660  *
661  * Return: acpi_status signaling success or error.
662  */
663 acpi_status wmi_install_notify_handler(const char *guid,
664 				       wmi_notify_handler handler,
665 				       void *data)
666 {
667 	struct wmi_block *block;
668 	acpi_status status = AE_NOT_EXIST;
669 	guid_t guid_input;
670 
671 	if (!guid || !handler)
672 		return AE_BAD_PARAMETER;
673 
674 	if (guid_parse(guid, &guid_input))
675 		return AE_BAD_PARAMETER;
676 
677 	list_for_each_entry(block, &wmi_block_list, list) {
678 		acpi_status wmi_status;
679 
680 		if (guid_equal(&block->gblock.guid, &guid_input)) {
681 			if (block->handler &&
682 			    block->handler != wmi_notify_debug)
683 				return AE_ALREADY_ACQUIRED;
684 
685 			block->handler = handler;
686 			block->handler_data = data;
687 
688 			wmi_status = wmi_method_enable(block, true);
689 			if ((wmi_status != AE_OK) ||
690 			    ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
691 				status = wmi_status;
692 		}
693 	}
694 
695 	return status;
696 }
697 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
698 
699 /**
700  * wmi_remove_notify_handler - Unregister handler for WMI events (deprecated)
701  * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
702  *
703  * Unregister handler for events sent to the ACPI-WMI mapper device.
704  *
705  * Return: acpi_status signaling success or error.
706  */
707 acpi_status wmi_remove_notify_handler(const char *guid)
708 {
709 	struct wmi_block *block;
710 	acpi_status status = AE_NOT_EXIST;
711 	guid_t guid_input;
712 
713 	if (!guid)
714 		return AE_BAD_PARAMETER;
715 
716 	if (guid_parse(guid, &guid_input))
717 		return AE_BAD_PARAMETER;
718 
719 	list_for_each_entry(block, &wmi_block_list, list) {
720 		acpi_status wmi_status;
721 
722 		if (guid_equal(&block->gblock.guid, &guid_input)) {
723 			if (!block->handler ||
724 			    block->handler == wmi_notify_debug)
725 				return AE_NULL_ENTRY;
726 
727 			if (debug_event) {
728 				block->handler = wmi_notify_debug;
729 				status = AE_OK;
730 			} else {
731 				wmi_status = wmi_method_enable(block, false);
732 				block->handler = NULL;
733 				block->handler_data = NULL;
734 				if ((wmi_status != AE_OK) ||
735 				    ((wmi_status == AE_OK) &&
736 				     (status == AE_NOT_EXIST)))
737 					status = wmi_status;
738 			}
739 		}
740 	}
741 
742 	return status;
743 }
744 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
745 
746 /**
747  * wmi_get_event_data - Get WMI data associated with an event (deprecated)
748  *
749  * @event: Event to find
750  * @out: Buffer to hold event data
751  *
752  * Get extra data associated with an WMI event, the caller needs to free @out.
753  *
754  * Return: acpi_status signaling success or error.
755  */
756 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
757 {
758 	struct wmi_block *wblock;
759 
760 	list_for_each_entry(wblock, &wmi_block_list, list) {
761 		struct guid_block *gblock = &wblock->gblock;
762 
763 		if ((gblock->flags & ACPI_WMI_EVENT) && gblock->notify_id == event)
764 			return get_event_data(wblock, out);
765 	}
766 
767 	return AE_NOT_FOUND;
768 }
769 EXPORT_SYMBOL_GPL(wmi_get_event_data);
770 
771 /**
772  * wmi_has_guid - Check if a GUID is available
773  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
774  *
775  * Check if a given GUID is defined by _WDG.
776  *
777  * Return: True if GUID is available, false otherwise.
778  */
779 bool wmi_has_guid(const char *guid_string)
780 {
781 	struct wmi_device *wdev;
782 
783 	wdev = wmi_find_device_by_guid(guid_string);
784 	if (IS_ERR(wdev))
785 		return false;
786 
787 	wmi_device_put(wdev);
788 
789 	return true;
790 }
791 EXPORT_SYMBOL_GPL(wmi_has_guid);
792 
793 /**
794  * wmi_get_acpi_device_uid() - Get _UID name of ACPI device that defines GUID (deprecated)
795  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
796  *
797  * Find the _UID of ACPI device associated with this WMI GUID.
798  *
799  * Return: The ACPI _UID field value or NULL if the WMI GUID was not found.
800  */
801 char *wmi_get_acpi_device_uid(const char *guid_string)
802 {
803 	struct wmi_block *wblock;
804 	struct wmi_device *wdev;
805 	char *uid;
806 
807 	wdev = wmi_find_device_by_guid(guid_string);
808 	if (IS_ERR(wdev))
809 		return NULL;
810 
811 	wblock = container_of(wdev, struct wmi_block, dev);
812 	uid = acpi_device_uid(wblock->acpi_device);
813 
814 	wmi_device_put(wdev);
815 
816 	return uid;
817 }
818 EXPORT_SYMBOL_GPL(wmi_get_acpi_device_uid);
819 
820 static inline struct wmi_driver *drv_to_wdrv(struct device_driver *drv)
821 {
822 	return container_of(drv, struct wmi_driver, driver);
823 }
824 
825 /*
826  * sysfs interface
827  */
828 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
829 			     char *buf)
830 {
831 	struct wmi_block *wblock = dev_to_wblock(dev);
832 
833 	return sysfs_emit(buf, "wmi:%pUL\n", &wblock->gblock.guid);
834 }
835 static DEVICE_ATTR_RO(modalias);
836 
837 static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
838 			 char *buf)
839 {
840 	struct wmi_block *wblock = dev_to_wblock(dev);
841 
842 	return sysfs_emit(buf, "%pUL\n", &wblock->gblock.guid);
843 }
844 static DEVICE_ATTR_RO(guid);
845 
846 static ssize_t instance_count_show(struct device *dev,
847 				   struct device_attribute *attr, char *buf)
848 {
849 	struct wmi_block *wblock = dev_to_wblock(dev);
850 
851 	return sysfs_emit(buf, "%d\n", (int)wblock->gblock.instance_count);
852 }
853 static DEVICE_ATTR_RO(instance_count);
854 
855 static ssize_t expensive_show(struct device *dev,
856 			      struct device_attribute *attr, char *buf)
857 {
858 	struct wmi_block *wblock = dev_to_wblock(dev);
859 
860 	return sysfs_emit(buf, "%d\n",
861 			  (wblock->gblock.flags & ACPI_WMI_EXPENSIVE) != 0);
862 }
863 static DEVICE_ATTR_RO(expensive);
864 
865 static struct attribute *wmi_attrs[] = {
866 	&dev_attr_modalias.attr,
867 	&dev_attr_guid.attr,
868 	&dev_attr_instance_count.attr,
869 	&dev_attr_expensive.attr,
870 	NULL
871 };
872 ATTRIBUTE_GROUPS(wmi);
873 
874 static ssize_t notify_id_show(struct device *dev, struct device_attribute *attr,
875 			      char *buf)
876 {
877 	struct wmi_block *wblock = dev_to_wblock(dev);
878 
879 	return sysfs_emit(buf, "%02X\n", (unsigned int)wblock->gblock.notify_id);
880 }
881 static DEVICE_ATTR_RO(notify_id);
882 
883 static struct attribute *wmi_event_attrs[] = {
884 	&dev_attr_notify_id.attr,
885 	NULL
886 };
887 ATTRIBUTE_GROUPS(wmi_event);
888 
889 static ssize_t object_id_show(struct device *dev, struct device_attribute *attr,
890 			      char *buf)
891 {
892 	struct wmi_block *wblock = dev_to_wblock(dev);
893 
894 	return sysfs_emit(buf, "%c%c\n", wblock->gblock.object_id[0],
895 			  wblock->gblock.object_id[1]);
896 }
897 static DEVICE_ATTR_RO(object_id);
898 
899 static ssize_t setable_show(struct device *dev, struct device_attribute *attr,
900 			    char *buf)
901 {
902 	struct wmi_device *wdev = dev_to_wdev(dev);
903 
904 	return sysfs_emit(buf, "%d\n", (int)wdev->setable);
905 }
906 static DEVICE_ATTR_RO(setable);
907 
908 static struct attribute *wmi_data_attrs[] = {
909 	&dev_attr_object_id.attr,
910 	&dev_attr_setable.attr,
911 	NULL
912 };
913 ATTRIBUTE_GROUPS(wmi_data);
914 
915 static struct attribute *wmi_method_attrs[] = {
916 	&dev_attr_object_id.attr,
917 	NULL
918 };
919 ATTRIBUTE_GROUPS(wmi_method);
920 
921 static int wmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
922 {
923 	const struct wmi_block *wblock = dev_to_wblock(dev);
924 
925 	if (add_uevent_var(env, "MODALIAS=wmi:%pUL", &wblock->gblock.guid))
926 		return -ENOMEM;
927 
928 	if (add_uevent_var(env, "WMI_GUID=%pUL", &wblock->gblock.guid))
929 		return -ENOMEM;
930 
931 	return 0;
932 }
933 
934 static void wmi_dev_release(struct device *dev)
935 {
936 	struct wmi_block *wblock = dev_to_wblock(dev);
937 
938 	kfree(wblock);
939 }
940 
941 static int wmi_dev_match(struct device *dev, struct device_driver *driver)
942 {
943 	struct wmi_driver *wmi_driver = drv_to_wdrv(driver);
944 	struct wmi_block *wblock = dev_to_wblock(dev);
945 	const struct wmi_device_id *id = wmi_driver->id_table;
946 
947 	if (id == NULL)
948 		return 0;
949 
950 	while (*id->guid_string) {
951 		if (guid_parse_and_compare(id->guid_string, &wblock->gblock.guid))
952 			return 1;
953 
954 		id++;
955 	}
956 
957 	return 0;
958 }
959 static int wmi_char_open(struct inode *inode, struct file *filp)
960 {
961 	/*
962 	 * The miscdevice already stores a pointer to itself
963 	 * inside filp->private_data
964 	 */
965 	struct wmi_block *wblock = container_of(filp->private_data, struct wmi_block, char_dev);
966 
967 	filp->private_data = wblock;
968 
969 	return nonseekable_open(inode, filp);
970 }
971 
972 static ssize_t wmi_char_read(struct file *filp, char __user *buffer,
973 			     size_t length, loff_t *offset)
974 {
975 	struct wmi_block *wblock = filp->private_data;
976 
977 	return simple_read_from_buffer(buffer, length, offset,
978 				       &wblock->req_buf_size,
979 				       sizeof(wblock->req_buf_size));
980 }
981 
982 static long wmi_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
983 {
984 	struct wmi_ioctl_buffer __user *input =
985 		(struct wmi_ioctl_buffer __user *) arg;
986 	struct wmi_block *wblock = filp->private_data;
987 	struct wmi_ioctl_buffer *buf;
988 	struct wmi_driver *wdriver;
989 	int ret;
990 
991 	if (_IOC_TYPE(cmd) != WMI_IOC)
992 		return -ENOTTY;
993 
994 	/* make sure we're not calling a higher instance than exists*/
995 	if (_IOC_NR(cmd) >= wblock->gblock.instance_count)
996 		return -EINVAL;
997 
998 	mutex_lock(&wblock->char_mutex);
999 	buf = wblock->handler_data;
1000 	if (get_user(buf->length, &input->length)) {
1001 		dev_dbg(&wblock->dev.dev, "Read length from user failed\n");
1002 		ret = -EFAULT;
1003 		goto out_ioctl;
1004 	}
1005 	/* if it's too small, abort */
1006 	if (buf->length < wblock->req_buf_size) {
1007 		dev_err(&wblock->dev.dev,
1008 			"Buffer %lld too small, need at least %lld\n",
1009 			buf->length, wblock->req_buf_size);
1010 		ret = -EINVAL;
1011 		goto out_ioctl;
1012 	}
1013 	/* if it's too big, warn, driver will only use what is needed */
1014 	if (buf->length > wblock->req_buf_size)
1015 		dev_warn(&wblock->dev.dev,
1016 			"Buffer %lld is bigger than required %lld\n",
1017 			buf->length, wblock->req_buf_size);
1018 
1019 	/* copy the structure from userspace */
1020 	if (copy_from_user(buf, input, wblock->req_buf_size)) {
1021 		dev_dbg(&wblock->dev.dev, "Copy %llu from user failed\n",
1022 			wblock->req_buf_size);
1023 		ret = -EFAULT;
1024 		goto out_ioctl;
1025 	}
1026 
1027 	/* let the driver do any filtering and do the call */
1028 	wdriver = drv_to_wdrv(wblock->dev.dev.driver);
1029 	if (!try_module_get(wdriver->driver.owner)) {
1030 		ret = -EBUSY;
1031 		goto out_ioctl;
1032 	}
1033 	ret = wdriver->filter_callback(&wblock->dev, cmd, buf);
1034 	module_put(wdriver->driver.owner);
1035 	if (ret)
1036 		goto out_ioctl;
1037 
1038 	/* return the result (only up to our internal buffer size) */
1039 	if (copy_to_user(input, buf, wblock->req_buf_size)) {
1040 		dev_dbg(&wblock->dev.dev, "Copy %llu to user failed\n",
1041 			wblock->req_buf_size);
1042 		ret = -EFAULT;
1043 	}
1044 
1045 out_ioctl:
1046 	mutex_unlock(&wblock->char_mutex);
1047 	return ret;
1048 }
1049 
1050 static const struct file_operations wmi_fops = {
1051 	.owner		= THIS_MODULE,
1052 	.read		= wmi_char_read,
1053 	.open		= wmi_char_open,
1054 	.unlocked_ioctl	= wmi_ioctl,
1055 	.compat_ioctl	= compat_ptr_ioctl,
1056 };
1057 
1058 static int wmi_dev_probe(struct device *dev)
1059 {
1060 	struct wmi_block *wblock = dev_to_wblock(dev);
1061 	struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
1062 	int ret = 0;
1063 	char *buf;
1064 
1065 	if (ACPI_FAILURE(wmi_method_enable(wblock, true)))
1066 		dev_warn(dev, "failed to enable device -- probing anyway\n");
1067 
1068 	if (wdriver->probe) {
1069 		ret = wdriver->probe(dev_to_wdev(dev),
1070 				find_guid_context(wblock, wdriver));
1071 		if (ret != 0)
1072 			goto probe_failure;
1073 	}
1074 
1075 	/* driver wants a character device made */
1076 	if (wdriver->filter_callback) {
1077 		/* check that required buffer size declared by driver or MOF */
1078 		if (!wblock->req_buf_size) {
1079 			dev_err(&wblock->dev.dev,
1080 				"Required buffer size not set\n");
1081 			ret = -EINVAL;
1082 			goto probe_failure;
1083 		}
1084 
1085 		wblock->handler_data = kmalloc(wblock->req_buf_size,
1086 					       GFP_KERNEL);
1087 		if (!wblock->handler_data) {
1088 			ret = -ENOMEM;
1089 			goto probe_failure;
1090 		}
1091 
1092 		buf = kasprintf(GFP_KERNEL, "wmi/%s", wdriver->driver.name);
1093 		if (!buf) {
1094 			ret = -ENOMEM;
1095 			goto probe_string_failure;
1096 		}
1097 		wblock->char_dev.minor = MISC_DYNAMIC_MINOR;
1098 		wblock->char_dev.name = buf;
1099 		wblock->char_dev.fops = &wmi_fops;
1100 		wblock->char_dev.mode = 0444;
1101 		ret = misc_register(&wblock->char_dev);
1102 		if (ret) {
1103 			dev_warn(dev, "failed to register char dev: %d\n", ret);
1104 			ret = -ENOMEM;
1105 			goto probe_misc_failure;
1106 		}
1107 	}
1108 
1109 	set_bit(WMI_PROBED, &wblock->flags);
1110 	return 0;
1111 
1112 probe_misc_failure:
1113 	kfree(buf);
1114 probe_string_failure:
1115 	kfree(wblock->handler_data);
1116 probe_failure:
1117 	if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
1118 		dev_warn(dev, "failed to disable device\n");
1119 	return ret;
1120 }
1121 
1122 static void wmi_dev_remove(struct device *dev)
1123 {
1124 	struct wmi_block *wblock = dev_to_wblock(dev);
1125 	struct wmi_driver *wdriver = drv_to_wdrv(dev->driver);
1126 
1127 	clear_bit(WMI_PROBED, &wblock->flags);
1128 
1129 	if (wdriver->filter_callback) {
1130 		misc_deregister(&wblock->char_dev);
1131 		kfree(wblock->char_dev.name);
1132 		kfree(wblock->handler_data);
1133 	}
1134 
1135 	if (wdriver->remove)
1136 		wdriver->remove(dev_to_wdev(dev));
1137 
1138 	if (ACPI_FAILURE(wmi_method_enable(wblock, false)))
1139 		dev_warn(dev, "failed to disable device\n");
1140 }
1141 
1142 static struct class wmi_bus_class = {
1143 	.name = "wmi_bus",
1144 };
1145 
1146 static struct bus_type wmi_bus_type = {
1147 	.name = "wmi",
1148 	.dev_groups = wmi_groups,
1149 	.match = wmi_dev_match,
1150 	.uevent = wmi_dev_uevent,
1151 	.probe = wmi_dev_probe,
1152 	.remove = wmi_dev_remove,
1153 };
1154 
1155 static const struct device_type wmi_type_event = {
1156 	.name = "event",
1157 	.groups = wmi_event_groups,
1158 	.release = wmi_dev_release,
1159 };
1160 
1161 static const struct device_type wmi_type_method = {
1162 	.name = "method",
1163 	.groups = wmi_method_groups,
1164 	.release = wmi_dev_release,
1165 };
1166 
1167 static const struct device_type wmi_type_data = {
1168 	.name = "data",
1169 	.groups = wmi_data_groups,
1170 	.release = wmi_dev_release,
1171 };
1172 
1173 /*
1174  * _WDG is a static list that is only parsed at startup,
1175  * so it's safe to count entries without extra protection.
1176  */
1177 static int guid_count(const guid_t *guid)
1178 {
1179 	struct wmi_block *wblock;
1180 	int count = 0;
1181 
1182 	list_for_each_entry(wblock, &wmi_block_list, list) {
1183 		if (guid_equal(&wblock->gblock.guid, guid))
1184 			count++;
1185 	}
1186 
1187 	return count;
1188 }
1189 
1190 static int wmi_create_device(struct device *wmi_bus_dev,
1191 			     struct wmi_block *wblock,
1192 			     struct acpi_device *device)
1193 {
1194 	struct acpi_device_info *info;
1195 	char method[WMI_ACPI_METHOD_NAME_SIZE];
1196 	int result;
1197 	uint count;
1198 
1199 	if (wblock->gblock.flags & ACPI_WMI_EVENT) {
1200 		wblock->dev.dev.type = &wmi_type_event;
1201 		goto out_init;
1202 	}
1203 
1204 	if (wblock->gblock.flags & ACPI_WMI_METHOD) {
1205 		wblock->dev.dev.type = &wmi_type_method;
1206 		mutex_init(&wblock->char_mutex);
1207 		goto out_init;
1208 	}
1209 
1210 	/*
1211 	 * Data Block Query Control Method (WQxx by convention) is
1212 	 * required per the WMI documentation. If it is not present,
1213 	 * we ignore this data block.
1214 	 */
1215 	get_acpi_method_name(wblock, 'Q', method);
1216 	result = get_subobj_info(device->handle, method, &info);
1217 
1218 	if (result) {
1219 		dev_warn(wmi_bus_dev,
1220 			 "%s data block query control method not found\n",
1221 			 method);
1222 		return result;
1223 	}
1224 
1225 	wblock->dev.dev.type = &wmi_type_data;
1226 
1227 	/*
1228 	 * The Microsoft documentation specifically states:
1229 	 *
1230 	 *   Data blocks registered with only a single instance
1231 	 *   can ignore the parameter.
1232 	 *
1233 	 * ACPICA will get mad at us if we call the method with the wrong number
1234 	 * of arguments, so check what our method expects.  (On some Dell
1235 	 * laptops, WQxx may not be a method at all.)
1236 	 */
1237 	if (info->type != ACPI_TYPE_METHOD || info->param_count == 0)
1238 		set_bit(WMI_READ_TAKES_NO_ARGS, &wblock->flags);
1239 
1240 	kfree(info);
1241 
1242 	get_acpi_method_name(wblock, 'S', method);
1243 	result = get_subobj_info(device->handle, method, NULL);
1244 
1245 	if (result == 0)
1246 		wblock->dev.setable = true;
1247 
1248  out_init:
1249 	wblock->dev.dev.bus = &wmi_bus_type;
1250 	wblock->dev.dev.parent = wmi_bus_dev;
1251 
1252 	count = guid_count(&wblock->gblock.guid);
1253 	if (count)
1254 		dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, count);
1255 	else
1256 		dev_set_name(&wblock->dev.dev, "%pUL", &wblock->gblock.guid);
1257 
1258 	device_initialize(&wblock->dev.dev);
1259 
1260 	return 0;
1261 }
1262 
1263 static int wmi_add_device(struct platform_device *pdev, struct wmi_device *wdev)
1264 {
1265 	struct device_link *link;
1266 
1267 	/*
1268 	 * Many aggregate WMI drivers do not use -EPROBE_DEFER when they
1269 	 * are unable to find a WMI device during probe, instead they require
1270 	 * all WMI devices associated with an platform device to become available
1271 	 * at once. This device link thus prevents WMI drivers from probing until
1272 	 * the associated platform device has finished probing (and has registered
1273 	 * all discovered WMI devices).
1274 	 */
1275 
1276 	link = device_link_add(&wdev->dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER);
1277 	if (!link)
1278 		return -EINVAL;
1279 
1280 	return device_add(&wdev->dev);
1281 }
1282 
1283 static bool guid_already_parsed_for_legacy(struct acpi_device *device, const guid_t *guid)
1284 {
1285 	struct wmi_block *wblock;
1286 
1287 	list_for_each_entry(wblock, &wmi_block_list, list) {
1288 		/* skip warning and register if we know the driver will use struct wmi_driver */
1289 		for (int i = 0; allow_duplicates[i] != NULL; i++) {
1290 			if (guid_parse_and_compare(allow_duplicates[i], guid))
1291 				return false;
1292 		}
1293 		if (guid_equal(&wblock->gblock.guid, guid)) {
1294 			/*
1295 			 * Because we historically didn't track the relationship
1296 			 * between GUIDs and ACPI nodes, we don't know whether
1297 			 * we need to suppress GUIDs that are unique on a
1298 			 * given node but duplicated across nodes.
1299 			 */
1300 			dev_warn(&device->dev, "duplicate WMI GUID %pUL (first instance was on %s)\n",
1301 				 guid, dev_name(&wblock->acpi_device->dev));
1302 			return true;
1303 		}
1304 	}
1305 
1306 	return false;
1307 }
1308 
1309 /*
1310  * Parse the _WDG method for the GUID data blocks
1311  */
1312 static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev)
1313 {
1314 	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
1315 	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
1316 	const struct guid_block *gblock;
1317 	struct wmi_block *wblock;
1318 	union acpi_object *obj;
1319 	acpi_status status;
1320 	u32 i, total;
1321 	int retval;
1322 
1323 	status = acpi_evaluate_object(device->handle, "_WDG", NULL, &out);
1324 	if (ACPI_FAILURE(status))
1325 		return -ENXIO;
1326 
1327 	obj = out.pointer;
1328 	if (!obj)
1329 		return -ENXIO;
1330 
1331 	if (obj->type != ACPI_TYPE_BUFFER) {
1332 		kfree(obj);
1333 		return -ENXIO;
1334 	}
1335 
1336 	gblock = (const struct guid_block *)obj->buffer.pointer;
1337 	total = obj->buffer.length / sizeof(struct guid_block);
1338 
1339 	for (i = 0; i < total; i++) {
1340 		if (debug_dump_wdg)
1341 			wmi_dump_wdg(&gblock[i]);
1342 
1343 		if (guid_already_parsed_for_legacy(device, &gblock[i].guid))
1344 			continue;
1345 
1346 		wblock = kzalloc(sizeof(*wblock), GFP_KERNEL);
1347 		if (!wblock) {
1348 			dev_err(wmi_bus_dev, "Failed to allocate %pUL\n", &gblock[i].guid);
1349 			continue;
1350 		}
1351 
1352 		wblock->acpi_device = device;
1353 		wblock->gblock = gblock[i];
1354 
1355 		retval = wmi_create_device(wmi_bus_dev, wblock, device);
1356 		if (retval) {
1357 			kfree(wblock);
1358 			continue;
1359 		}
1360 
1361 		list_add_tail(&wblock->list, &wmi_block_list);
1362 
1363 		if (debug_event) {
1364 			wblock->handler = wmi_notify_debug;
1365 			wmi_method_enable(wblock, true);
1366 		}
1367 
1368 		retval = wmi_add_device(pdev, &wblock->dev);
1369 		if (retval) {
1370 			dev_err(wmi_bus_dev, "failed to register %pUL\n",
1371 				&wblock->gblock.guid);
1372 			if (debug_event)
1373 				wmi_method_enable(wblock, false);
1374 
1375 			list_del(&wblock->list);
1376 			put_device(&wblock->dev.dev);
1377 		}
1378 	}
1379 
1380 	kfree(obj);
1381 
1382 	return 0;
1383 }
1384 
1385 /*
1386  * WMI can have EmbeddedControl access regions. In which case, we just want to
1387  * hand these off to the EC driver.
1388  */
1389 static acpi_status
1390 acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
1391 			  u32 bits, u64 *value,
1392 			  void *handler_context, void *region_context)
1393 {
1394 	int result = 0, i = 0;
1395 	u8 temp = 0;
1396 
1397 	if ((address > 0xFF) || !value)
1398 		return AE_BAD_PARAMETER;
1399 
1400 	if (function != ACPI_READ && function != ACPI_WRITE)
1401 		return AE_BAD_PARAMETER;
1402 
1403 	if (bits != 8)
1404 		return AE_BAD_PARAMETER;
1405 
1406 	if (function == ACPI_READ) {
1407 		result = ec_read(address, &temp);
1408 		(*value) |= ((u64)temp) << i;
1409 	} else {
1410 		temp = 0xff & ((*value) >> i);
1411 		result = ec_write(address, temp);
1412 	}
1413 
1414 	switch (result) {
1415 	case -EINVAL:
1416 		return AE_BAD_PARAMETER;
1417 	case -ENODEV:
1418 		return AE_NOT_FOUND;
1419 	case -ETIME:
1420 		return AE_TIME;
1421 	default:
1422 		return AE_OK;
1423 	}
1424 }
1425 
1426 static void acpi_wmi_notify_handler(acpi_handle handle, u32 event,
1427 				    void *context)
1428 {
1429 	struct wmi_block *wblock = NULL, *iter;
1430 
1431 	list_for_each_entry(iter, &wmi_block_list, list) {
1432 		struct guid_block *block = &iter->gblock;
1433 
1434 		if (iter->acpi_device->handle == handle &&
1435 		    (block->flags & ACPI_WMI_EVENT) &&
1436 		    (block->notify_id == event)) {
1437 			wblock = iter;
1438 			break;
1439 		}
1440 	}
1441 
1442 	if (!wblock)
1443 		return;
1444 
1445 	/* If a driver is bound, then notify the driver. */
1446 	if (test_bit(WMI_PROBED, &wblock->flags) && wblock->dev.dev.driver) {
1447 		struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
1448 		struct acpi_buffer evdata = { ACPI_ALLOCATE_BUFFER, NULL };
1449 		acpi_status status;
1450 
1451 		if (!driver->no_notify_data) {
1452 			status = get_event_data(wblock, &evdata);
1453 			if (ACPI_FAILURE(status)) {
1454 				dev_warn(&wblock->dev.dev, "failed to get event data\n");
1455 				return;
1456 			}
1457 		}
1458 
1459 		if (driver->notify)
1460 			driver->notify(&wblock->dev, evdata.pointer);
1461 
1462 		kfree(evdata.pointer);
1463 	} else if (wblock->handler) {
1464 		/* Legacy handler */
1465 		wblock->handler(event, wblock->handler_data);
1466 	}
1467 
1468 	if (debug_event)
1469 		pr_info("DEBUG: GUID %pUL event 0x%02X\n", &wblock->gblock.guid, event);
1470 
1471 	acpi_bus_generate_netlink_event(
1472 		wblock->acpi_device->pnp.device_class,
1473 		dev_name(&wblock->dev.dev),
1474 		event, 0);
1475 }
1476 
1477 static int wmi_remove_device(struct device *dev, void *data)
1478 {
1479 	struct wmi_block *wblock = dev_to_wblock(dev);
1480 
1481 	list_del(&wblock->list);
1482 	device_unregister(dev);
1483 
1484 	return 0;
1485 }
1486 
1487 static void acpi_wmi_remove(struct platform_device *device)
1488 {
1489 	struct acpi_device *acpi_device = ACPI_COMPANION(&device->dev);
1490 	struct device *wmi_bus_device = dev_get_drvdata(&device->dev);
1491 
1492 	acpi_remove_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY,
1493 				   acpi_wmi_notify_handler);
1494 	acpi_remove_address_space_handler(acpi_device->handle,
1495 				ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
1496 
1497 	device_for_each_child_reverse(wmi_bus_device, NULL, wmi_remove_device);
1498 	device_unregister(wmi_bus_device);
1499 }
1500 
1501 static int acpi_wmi_probe(struct platform_device *device)
1502 {
1503 	struct acpi_device *acpi_device;
1504 	struct device *wmi_bus_dev;
1505 	acpi_status status;
1506 	int error;
1507 
1508 	acpi_device = ACPI_COMPANION(&device->dev);
1509 	if (!acpi_device) {
1510 		dev_err(&device->dev, "ACPI companion is missing\n");
1511 		return -ENODEV;
1512 	}
1513 
1514 	status = acpi_install_address_space_handler(acpi_device->handle,
1515 						    ACPI_ADR_SPACE_EC,
1516 						    &acpi_wmi_ec_space_handler,
1517 						    NULL, NULL);
1518 	if (ACPI_FAILURE(status)) {
1519 		dev_err(&device->dev, "Error installing EC region handler\n");
1520 		return -ENODEV;
1521 	}
1522 
1523 	status = acpi_install_notify_handler(acpi_device->handle,
1524 					     ACPI_ALL_NOTIFY,
1525 					     acpi_wmi_notify_handler,
1526 					     NULL);
1527 	if (ACPI_FAILURE(status)) {
1528 		dev_err(&device->dev, "Error installing notify handler\n");
1529 		error = -ENODEV;
1530 		goto err_remove_ec_handler;
1531 	}
1532 
1533 	wmi_bus_dev = device_create(&wmi_bus_class, &device->dev, MKDEV(0, 0),
1534 				    NULL, "wmi_bus-%s", dev_name(&device->dev));
1535 	if (IS_ERR(wmi_bus_dev)) {
1536 		error = PTR_ERR(wmi_bus_dev);
1537 		goto err_remove_notify_handler;
1538 	}
1539 	dev_set_drvdata(&device->dev, wmi_bus_dev);
1540 
1541 	error = parse_wdg(wmi_bus_dev, device);
1542 	if (error) {
1543 		pr_err("Failed to parse WDG method\n");
1544 		goto err_remove_busdev;
1545 	}
1546 
1547 	return 0;
1548 
1549 err_remove_busdev:
1550 	device_unregister(wmi_bus_dev);
1551 
1552 err_remove_notify_handler:
1553 	acpi_remove_notify_handler(acpi_device->handle, ACPI_ALL_NOTIFY,
1554 				   acpi_wmi_notify_handler);
1555 
1556 err_remove_ec_handler:
1557 	acpi_remove_address_space_handler(acpi_device->handle,
1558 					  ACPI_ADR_SPACE_EC,
1559 					  &acpi_wmi_ec_space_handler);
1560 
1561 	return error;
1562 }
1563 
1564 int __must_check __wmi_driver_register(struct wmi_driver *driver,
1565 				       struct module *owner)
1566 {
1567 	driver->driver.owner = owner;
1568 	driver->driver.bus = &wmi_bus_type;
1569 
1570 	return driver_register(&driver->driver);
1571 }
1572 EXPORT_SYMBOL(__wmi_driver_register);
1573 
1574 /**
1575  * wmi_driver_unregister() - Unregister a WMI driver
1576  * @driver: WMI driver to unregister
1577  *
1578  * Unregisters a WMI driver from the WMI bus.
1579  */
1580 void wmi_driver_unregister(struct wmi_driver *driver)
1581 {
1582 	driver_unregister(&driver->driver);
1583 }
1584 EXPORT_SYMBOL(wmi_driver_unregister);
1585 
1586 static struct platform_driver acpi_wmi_driver = {
1587 	.driver = {
1588 		.name = "acpi-wmi",
1589 		.acpi_match_table = wmi_device_ids,
1590 	},
1591 	.probe = acpi_wmi_probe,
1592 	.remove_new = acpi_wmi_remove,
1593 };
1594 
1595 static int __init acpi_wmi_init(void)
1596 {
1597 	int error;
1598 
1599 	if (acpi_disabled)
1600 		return -ENODEV;
1601 
1602 	error = class_register(&wmi_bus_class);
1603 	if (error)
1604 		return error;
1605 
1606 	error = bus_register(&wmi_bus_type);
1607 	if (error)
1608 		goto err_unreg_class;
1609 
1610 	error = platform_driver_register(&acpi_wmi_driver);
1611 	if (error) {
1612 		pr_err("Error loading mapper\n");
1613 		goto err_unreg_bus;
1614 	}
1615 
1616 	return 0;
1617 
1618 err_unreg_bus:
1619 	bus_unregister(&wmi_bus_type);
1620 
1621 err_unreg_class:
1622 	class_unregister(&wmi_bus_class);
1623 
1624 	return error;
1625 }
1626 
1627 static void __exit acpi_wmi_exit(void)
1628 {
1629 	platform_driver_unregister(&acpi_wmi_driver);
1630 	bus_unregister(&wmi_bus_type);
1631 	class_unregister(&wmi_bus_class);
1632 }
1633 
1634 subsys_initcall_sync(acpi_wmi_init);
1635 module_exit(acpi_wmi_exit);
1636