xref: /linux/drivers/platform/x86/wmi.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*
2  *  ACPI-WMI mapping driver
3  *
4  *  Copyright (C) 2007-2008 Carlos Corbacho <carlos@strangeworlds.co.uk>
5  *
6  *  GUID parsing code from ldm.c is:
7  *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
8  *   Copyright (c) 2001-2007 Anton Altaparmakov
9  *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
10  *
11  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12  *
13  *  This program is free software; you can redistribute it and/or modify
14  *  it under the terms of the GNU General Public License as published by
15  *  the Free Software Foundation; either version 2 of the License, or (at
16  *  your option) any later version.
17  *
18  *  This program is distributed in the hope that it will be useful, but
19  *  WITHOUT ANY WARRANTY; without even the implied warranty of
20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  *  General Public License for more details.
22  *
23  *  You should have received a copy of the GNU General Public License along
24  *  with this program; if not, write to the Free Software Foundation, Inc.,
25  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
26  *
27  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
28  */
29 
30 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
31 
32 #include <linux/kernel.h>
33 #include <linux/init.h>
34 #include <linux/types.h>
35 #include <linux/device.h>
36 #include <linux/list.h>
37 #include <linux/acpi.h>
38 #include <linux/slab.h>
39 #include <linux/module.h>
40 #include <linux/uuid.h>
41 
42 ACPI_MODULE_NAME("wmi");
43 MODULE_AUTHOR("Carlos Corbacho");
44 MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
45 MODULE_LICENSE("GPL");
46 
47 #define ACPI_WMI_CLASS "wmi"
48 
49 static LIST_HEAD(wmi_block_list);
50 
51 struct guid_block {
52 	char guid[16];
53 	union {
54 		char object_id[2];
55 		struct {
56 			unsigned char notify_id;
57 			unsigned char reserved;
58 		};
59 	};
60 	u8 instance_count;
61 	u8 flags;
62 };
63 
64 struct wmi_block {
65 	struct list_head list;
66 	struct guid_block gblock;
67 	acpi_handle handle;
68 	wmi_notify_handler handler;
69 	void *handler_data;
70 	struct device dev;
71 };
72 
73 
74 /*
75  * If the GUID data block is marked as expensive, we must enable and
76  * explicitily disable data collection.
77  */
78 #define ACPI_WMI_EXPENSIVE   0x1
79 #define ACPI_WMI_METHOD      0x2	/* GUID is a method */
80 #define ACPI_WMI_STRING      0x4	/* GUID takes & returns a string */
81 #define ACPI_WMI_EVENT       0x8	/* GUID is an event */
82 
83 static bool debug_event;
84 module_param(debug_event, bool, 0444);
85 MODULE_PARM_DESC(debug_event,
86 		 "Log WMI Events [0/1]");
87 
88 static bool debug_dump_wdg;
89 module_param(debug_dump_wdg, bool, 0444);
90 MODULE_PARM_DESC(debug_dump_wdg,
91 		 "Dump available WMI interfaces [0/1]");
92 
93 static int acpi_wmi_remove(struct acpi_device *device);
94 static int acpi_wmi_add(struct acpi_device *device);
95 static void acpi_wmi_notify(struct acpi_device *device, u32 event);
96 
97 static const struct acpi_device_id wmi_device_ids[] = {
98 	{"PNP0C14", 0},
99 	{"pnp0c14", 0},
100 	{"", 0},
101 };
102 MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
103 
104 static struct acpi_driver acpi_wmi_driver = {
105 	.name = "wmi",
106 	.class = ACPI_WMI_CLASS,
107 	.ids = wmi_device_ids,
108 	.ops = {
109 		.add = acpi_wmi_add,
110 		.remove = acpi_wmi_remove,
111 		.notify = acpi_wmi_notify,
112 	},
113 };
114 
115 /*
116  * GUID parsing functions
117  */
118 
119 static bool find_guid(const char *guid_string, struct wmi_block **out)
120 {
121 	uuid_le guid_input;
122 	struct wmi_block *wblock;
123 	struct guid_block *block;
124 	struct list_head *p;
125 
126 	if (uuid_le_to_bin(guid_string, &guid_input))
127 		return false;
128 
129 	list_for_each(p, &wmi_block_list) {
130 		wblock = list_entry(p, struct wmi_block, list);
131 		block = &wblock->gblock;
132 
133 		if (memcmp(block->guid, &guid_input, 16) == 0) {
134 			if (out)
135 				*out = wblock;
136 			return true;
137 		}
138 	}
139 	return false;
140 }
141 
142 static acpi_status wmi_method_enable(struct wmi_block *wblock, int enable)
143 {
144 	struct guid_block *block = NULL;
145 	char method[5];
146 	acpi_status status;
147 	acpi_handle handle;
148 
149 	block = &wblock->gblock;
150 	handle = wblock->handle;
151 
152 	snprintf(method, 5, "WE%02X", block->notify_id);
153 	status = acpi_execute_simple_method(handle, method, enable);
154 
155 	if (status != AE_OK && status != AE_NOT_FOUND)
156 		return status;
157 	else
158 		return AE_OK;
159 }
160 
161 /*
162  * Exported WMI functions
163  */
164 /**
165  * wmi_evaluate_method - Evaluate a WMI method
166  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
167  * @instance: Instance index
168  * @method_id: Method ID to call
169  * &in: Buffer containing input for the method call
170  * &out: Empty buffer to return the method results
171  *
172  * Call an ACPI-WMI method
173  */
174 acpi_status wmi_evaluate_method(const char *guid_string, u8 instance,
175 u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
176 {
177 	struct guid_block *block = NULL;
178 	struct wmi_block *wblock = NULL;
179 	acpi_handle handle;
180 	acpi_status status;
181 	struct acpi_object_list input;
182 	union acpi_object params[3];
183 	char method[5] = "WM";
184 
185 	if (!find_guid(guid_string, &wblock))
186 		return AE_ERROR;
187 
188 	block = &wblock->gblock;
189 	handle = wblock->handle;
190 
191 	if (!(block->flags & ACPI_WMI_METHOD))
192 		return AE_BAD_DATA;
193 
194 	if (block->instance_count < instance)
195 		return AE_BAD_PARAMETER;
196 
197 	input.count = 2;
198 	input.pointer = params;
199 	params[0].type = ACPI_TYPE_INTEGER;
200 	params[0].integer.value = instance;
201 	params[1].type = ACPI_TYPE_INTEGER;
202 	params[1].integer.value = method_id;
203 
204 	if (in) {
205 		input.count = 3;
206 
207 		if (block->flags & ACPI_WMI_STRING) {
208 			params[2].type = ACPI_TYPE_STRING;
209 		} else {
210 			params[2].type = ACPI_TYPE_BUFFER;
211 		}
212 		params[2].buffer.length = in->length;
213 		params[2].buffer.pointer = in->pointer;
214 	}
215 
216 	strncat(method, block->object_id, 2);
217 
218 	status = acpi_evaluate_object(handle, method, &input, out);
219 
220 	return status;
221 }
222 EXPORT_SYMBOL_GPL(wmi_evaluate_method);
223 
224 /**
225  * wmi_query_block - Return contents of a WMI block
226  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
227  * @instance: Instance index
228  * &out: Empty buffer to return the contents of the data block to
229  *
230  * Return the contents of an ACPI-WMI data block to a buffer
231  */
232 acpi_status wmi_query_block(const char *guid_string, u8 instance,
233 struct acpi_buffer *out)
234 {
235 	struct guid_block *block = NULL;
236 	struct wmi_block *wblock = NULL;
237 	acpi_handle handle;
238 	acpi_status status, wc_status = AE_ERROR;
239 	struct acpi_object_list input;
240 	union acpi_object wq_params[1];
241 	char method[5];
242 	char wc_method[5] = "WC";
243 
244 	if (!guid_string || !out)
245 		return AE_BAD_PARAMETER;
246 
247 	if (!find_guid(guid_string, &wblock))
248 		return AE_ERROR;
249 
250 	block = &wblock->gblock;
251 	handle = wblock->handle;
252 
253 	if (block->instance_count < instance)
254 		return AE_BAD_PARAMETER;
255 
256 	/* Check GUID is a data block */
257 	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
258 		return AE_ERROR;
259 
260 	input.count = 1;
261 	input.pointer = wq_params;
262 	wq_params[0].type = ACPI_TYPE_INTEGER;
263 	wq_params[0].integer.value = instance;
264 
265 	/*
266 	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method first to
267 	 * enable collection.
268 	 */
269 	if (block->flags & ACPI_WMI_EXPENSIVE) {
270 		strncat(wc_method, block->object_id, 2);
271 
272 		/*
273 		 * Some GUIDs break the specification by declaring themselves
274 		 * expensive, but have no corresponding WCxx method. So we
275 		 * should not fail if this happens.
276 		 */
277 		if (acpi_has_method(handle, wc_method))
278 			wc_status = acpi_execute_simple_method(handle,
279 								wc_method, 1);
280 	}
281 
282 	strcpy(method, "WQ");
283 	strncat(method, block->object_id, 2);
284 
285 	status = acpi_evaluate_object(handle, method, &input, out);
286 
287 	/*
288 	 * If ACPI_WMI_EXPENSIVE, call the relevant WCxx method, even if
289 	 * the WQxx method failed - we should disable collection anyway.
290 	 */
291 	if ((block->flags & ACPI_WMI_EXPENSIVE) && ACPI_SUCCESS(wc_status)) {
292 		status = acpi_execute_simple_method(handle, wc_method, 0);
293 	}
294 
295 	return status;
296 }
297 EXPORT_SYMBOL_GPL(wmi_query_block);
298 
299 /**
300  * wmi_set_block - Write to a WMI block
301  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
302  * @instance: Instance index
303  * &in: Buffer containing new values for the data block
304  *
305  * Write the contents of the input buffer to an ACPI-WMI data block
306  */
307 acpi_status wmi_set_block(const char *guid_string, u8 instance,
308 const struct acpi_buffer *in)
309 {
310 	struct guid_block *block = NULL;
311 	struct wmi_block *wblock = NULL;
312 	acpi_handle handle;
313 	struct acpi_object_list input;
314 	union acpi_object params[2];
315 	char method[5] = "WS";
316 
317 	if (!guid_string || !in)
318 		return AE_BAD_DATA;
319 
320 	if (!find_guid(guid_string, &wblock))
321 		return AE_ERROR;
322 
323 	block = &wblock->gblock;
324 	handle = wblock->handle;
325 
326 	if (block->instance_count < instance)
327 		return AE_BAD_PARAMETER;
328 
329 	/* Check GUID is a data block */
330 	if (block->flags & (ACPI_WMI_EVENT | ACPI_WMI_METHOD))
331 		return AE_ERROR;
332 
333 	input.count = 2;
334 	input.pointer = params;
335 	params[0].type = ACPI_TYPE_INTEGER;
336 	params[0].integer.value = instance;
337 
338 	if (block->flags & ACPI_WMI_STRING) {
339 		params[1].type = ACPI_TYPE_STRING;
340 	} else {
341 		params[1].type = ACPI_TYPE_BUFFER;
342 	}
343 	params[1].buffer.length = in->length;
344 	params[1].buffer.pointer = in->pointer;
345 
346 	strncat(method, block->object_id, 2);
347 
348 	return acpi_evaluate_object(handle, method, &input, NULL);
349 }
350 EXPORT_SYMBOL_GPL(wmi_set_block);
351 
352 static void wmi_dump_wdg(const struct guid_block *g)
353 {
354 	pr_info("%pUL:\n", g->guid);
355 	pr_info("\tobject_id: %c%c\n", g->object_id[0], g->object_id[1]);
356 	pr_info("\tnotify_id: %02X\n", g->notify_id);
357 	pr_info("\treserved: %02X\n", g->reserved);
358 	pr_info("\tinstance_count: %d\n", g->instance_count);
359 	pr_info("\tflags: %#x", g->flags);
360 	if (g->flags) {
361 		if (g->flags & ACPI_WMI_EXPENSIVE)
362 			pr_cont(" ACPI_WMI_EXPENSIVE");
363 		if (g->flags & ACPI_WMI_METHOD)
364 			pr_cont(" ACPI_WMI_METHOD");
365 		if (g->flags & ACPI_WMI_STRING)
366 			pr_cont(" ACPI_WMI_STRING");
367 		if (g->flags & ACPI_WMI_EVENT)
368 			pr_cont(" ACPI_WMI_EVENT");
369 	}
370 	pr_cont("\n");
371 
372 }
373 
374 static void wmi_notify_debug(u32 value, void *context)
375 {
376 	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
377 	union acpi_object *obj;
378 	acpi_status status;
379 
380 	status = wmi_get_event_data(value, &response);
381 	if (status != AE_OK) {
382 		pr_info("bad event status 0x%x\n", status);
383 		return;
384 	}
385 
386 	obj = (union acpi_object *)response.pointer;
387 
388 	if (!obj)
389 		return;
390 
391 	pr_info("DEBUG Event ");
392 	switch(obj->type) {
393 	case ACPI_TYPE_BUFFER:
394 		pr_cont("BUFFER_TYPE - length %d\n", obj->buffer.length);
395 		break;
396 	case ACPI_TYPE_STRING:
397 		pr_cont("STRING_TYPE - %s\n", obj->string.pointer);
398 		break;
399 	case ACPI_TYPE_INTEGER:
400 		pr_cont("INTEGER_TYPE - %llu\n", obj->integer.value);
401 		break;
402 	case ACPI_TYPE_PACKAGE:
403 		pr_cont("PACKAGE_TYPE - %d elements\n", obj->package.count);
404 		break;
405 	default:
406 		pr_cont("object type 0x%X\n", obj->type);
407 	}
408 	kfree(obj);
409 }
410 
411 /**
412  * wmi_install_notify_handler - Register handler for WMI events
413  * @handler: Function to handle notifications
414  * @data: Data to be returned to handler when event is fired
415  *
416  * Register a handler for events sent to the ACPI-WMI mapper device.
417  */
418 acpi_status wmi_install_notify_handler(const char *guid,
419 wmi_notify_handler handler, void *data)
420 {
421 	struct wmi_block *block;
422 	acpi_status status = AE_NOT_EXIST;
423 	uuid_le guid_input;
424 	struct list_head *p;
425 
426 	if (!guid || !handler)
427 		return AE_BAD_PARAMETER;
428 
429 	if (uuid_le_to_bin(guid, &guid_input))
430 		return AE_BAD_PARAMETER;
431 
432 	list_for_each(p, &wmi_block_list) {
433 		acpi_status wmi_status;
434 		block = list_entry(p, struct wmi_block, list);
435 
436 		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
437 			if (block->handler &&
438 			    block->handler != wmi_notify_debug)
439 				return AE_ALREADY_ACQUIRED;
440 
441 			block->handler = handler;
442 			block->handler_data = data;
443 
444 			wmi_status = wmi_method_enable(block, 1);
445 			if ((wmi_status != AE_OK) ||
446 			    ((wmi_status == AE_OK) && (status == AE_NOT_EXIST)))
447 				status = wmi_status;
448 		}
449 	}
450 
451 	return status;
452 }
453 EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
454 
455 /**
456  * wmi_uninstall_notify_handler - Unregister handler for WMI events
457  *
458  * Unregister handler for events sent to the ACPI-WMI mapper device.
459  */
460 acpi_status wmi_remove_notify_handler(const char *guid)
461 {
462 	struct wmi_block *block;
463 	acpi_status status = AE_NOT_EXIST;
464 	uuid_le guid_input;
465 	struct list_head *p;
466 
467 	if (!guid)
468 		return AE_BAD_PARAMETER;
469 
470 	if (uuid_le_to_bin(guid, &guid_input))
471 		return AE_BAD_PARAMETER;
472 
473 	list_for_each(p, &wmi_block_list) {
474 		acpi_status wmi_status;
475 		block = list_entry(p, struct wmi_block, list);
476 
477 		if (memcmp(block->gblock.guid, &guid_input, 16) == 0) {
478 			if (!block->handler ||
479 			    block->handler == wmi_notify_debug)
480 				return AE_NULL_ENTRY;
481 
482 			if (debug_event) {
483 				block->handler = wmi_notify_debug;
484 				status = AE_OK;
485 			} else {
486 				wmi_status = wmi_method_enable(block, 0);
487 				block->handler = NULL;
488 				block->handler_data = NULL;
489 				if ((wmi_status != AE_OK) ||
490 				    ((wmi_status == AE_OK) &&
491 				     (status == AE_NOT_EXIST)))
492 					status = wmi_status;
493 			}
494 		}
495 	}
496 
497 	return status;
498 }
499 EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
500 
501 /**
502  * wmi_get_event_data - Get WMI data associated with an event
503  *
504  * @event: Event to find
505  * @out: Buffer to hold event data. out->pointer should be freed with kfree()
506  *
507  * Returns extra data associated with an event in WMI.
508  */
509 acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
510 {
511 	struct acpi_object_list input;
512 	union acpi_object params[1];
513 	struct guid_block *gblock;
514 	struct wmi_block *wblock;
515 	struct list_head *p;
516 
517 	input.count = 1;
518 	input.pointer = params;
519 	params[0].type = ACPI_TYPE_INTEGER;
520 	params[0].integer.value = event;
521 
522 	list_for_each(p, &wmi_block_list) {
523 		wblock = list_entry(p, struct wmi_block, list);
524 		gblock = &wblock->gblock;
525 
526 		if ((gblock->flags & ACPI_WMI_EVENT) &&
527 			(gblock->notify_id == event))
528 			return acpi_evaluate_object(wblock->handle, "_WED",
529 				&input, out);
530 	}
531 
532 	return AE_NOT_FOUND;
533 }
534 EXPORT_SYMBOL_GPL(wmi_get_event_data);
535 
536 /**
537  * wmi_has_guid - Check if a GUID is available
538  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
539  *
540  * Check if a given GUID is defined by _WDG
541  */
542 bool wmi_has_guid(const char *guid_string)
543 {
544 	return find_guid(guid_string, NULL);
545 }
546 EXPORT_SYMBOL_GPL(wmi_has_guid);
547 
548 /*
549  * sysfs interface
550  */
551 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
552 			     char *buf)
553 {
554 	struct wmi_block *wblock;
555 
556 	wblock = dev_get_drvdata(dev);
557 	if (!wblock) {
558 		strcat(buf, "\n");
559 		return strlen(buf);
560 	}
561 
562 	return sprintf(buf, "wmi:%pUL\n", wblock->gblock.guid);
563 }
564 static DEVICE_ATTR_RO(modalias);
565 
566 static struct attribute *wmi_attrs[] = {
567 	&dev_attr_modalias.attr,
568 	NULL,
569 };
570 ATTRIBUTE_GROUPS(wmi);
571 
572 static int wmi_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
573 {
574 	char guid_string[37];
575 
576 	struct wmi_block *wblock;
577 
578 	if (add_uevent_var(env, "MODALIAS="))
579 		return -ENOMEM;
580 
581 	wblock = dev_get_drvdata(dev);
582 	if (!wblock)
583 		return -ENOMEM;
584 
585 	sprintf(guid_string, "%pUL", wblock->gblock.guid);
586 
587 	strcpy(&env->buf[env->buflen - 1], "wmi:");
588 	memcpy(&env->buf[env->buflen - 1 + 4], guid_string, 36);
589 	env->buflen += 40;
590 
591 	return 0;
592 }
593 
594 static void wmi_dev_free(struct device *dev)
595 {
596 	struct wmi_block *wmi_block = container_of(dev, struct wmi_block, dev);
597 
598 	kfree(wmi_block);
599 }
600 
601 static struct class wmi_class = {
602 	.name = "wmi",
603 	.dev_release = wmi_dev_free,
604 	.dev_uevent = wmi_dev_uevent,
605 	.dev_groups = wmi_groups,
606 };
607 
608 static int wmi_create_device(const struct guid_block *gblock,
609 			     struct wmi_block *wblock, acpi_handle handle)
610 {
611 	wblock->dev.class = &wmi_class;
612 
613 	dev_set_name(&wblock->dev, "%pUL", gblock->guid);
614 
615 	dev_set_drvdata(&wblock->dev, wblock);
616 
617 	return device_register(&wblock->dev);
618 }
619 
620 static void wmi_free_devices(void)
621 {
622 	struct wmi_block *wblock, *next;
623 
624 	/* Delete devices for all the GUIDs */
625 	list_for_each_entry_safe(wblock, next, &wmi_block_list, list) {
626 		list_del(&wblock->list);
627 		if (wblock->dev.class)
628 			device_unregister(&wblock->dev);
629 		else
630 			kfree(wblock);
631 	}
632 }
633 
634 static bool guid_already_parsed(const char *guid_string)
635 {
636 	struct wmi_block *wblock;
637 
638 	list_for_each_entry(wblock, &wmi_block_list, list)
639 		if (memcmp(wblock->gblock.guid, guid_string, 16) == 0)
640 			return true;
641 
642 	return false;
643 }
644 
645 /*
646  * Parse the _WDG method for the GUID data blocks
647  */
648 static int parse_wdg(acpi_handle handle)
649 {
650 	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
651 	union acpi_object *obj;
652 	const struct guid_block *gblock;
653 	struct wmi_block *wblock;
654 	acpi_status status;
655 	int retval;
656 	u32 i, total;
657 
658 	status = acpi_evaluate_object(handle, "_WDG", NULL, &out);
659 	if (ACPI_FAILURE(status))
660 		return -ENXIO;
661 
662 	obj = (union acpi_object *) out.pointer;
663 	if (!obj)
664 		return -ENXIO;
665 
666 	if (obj->type != ACPI_TYPE_BUFFER) {
667 		retval = -ENXIO;
668 		goto out_free_pointer;
669 	}
670 
671 	gblock = (const struct guid_block *)obj->buffer.pointer;
672 	total = obj->buffer.length / sizeof(struct guid_block);
673 
674 	for (i = 0; i < total; i++) {
675 		if (debug_dump_wdg)
676 			wmi_dump_wdg(&gblock[i]);
677 
678 		wblock = kzalloc(sizeof(struct wmi_block), GFP_KERNEL);
679 		if (!wblock)
680 			return -ENOMEM;
681 
682 		wblock->handle = handle;
683 		wblock->gblock = gblock[i];
684 
685 		/*
686 		  Some WMI devices, like those for nVidia hooks, have a
687 		  duplicate GUID. It's not clear what we should do in this
688 		  case yet, so for now, we'll just ignore the duplicate
689 		  for device creation.
690 		*/
691 		if (!guid_already_parsed(gblock[i].guid)) {
692 			retval = wmi_create_device(&gblock[i], wblock, handle);
693 			if (retval) {
694 				wmi_free_devices();
695 				goto out_free_pointer;
696 			}
697 		}
698 
699 		list_add_tail(&wblock->list, &wmi_block_list);
700 
701 		if (debug_event) {
702 			wblock->handler = wmi_notify_debug;
703 			wmi_method_enable(wblock, 1);
704 		}
705 	}
706 
707 	retval = 0;
708 
709 out_free_pointer:
710 	kfree(out.pointer);
711 
712 	return retval;
713 }
714 
715 /*
716  * WMI can have EmbeddedControl access regions. In which case, we just want to
717  * hand these off to the EC driver.
718  */
719 static acpi_status
720 acpi_wmi_ec_space_handler(u32 function, acpi_physical_address address,
721 		      u32 bits, u64 *value,
722 		      void *handler_context, void *region_context)
723 {
724 	int result = 0, i = 0;
725 	u8 temp = 0;
726 
727 	if ((address > 0xFF) || !value)
728 		return AE_BAD_PARAMETER;
729 
730 	if (function != ACPI_READ && function != ACPI_WRITE)
731 		return AE_BAD_PARAMETER;
732 
733 	if (bits != 8)
734 		return AE_BAD_PARAMETER;
735 
736 	if (function == ACPI_READ) {
737 		result = ec_read(address, &temp);
738 		(*value) |= ((u64)temp) << i;
739 	} else {
740 		temp = 0xff & ((*value) >> i);
741 		result = ec_write(address, temp);
742 	}
743 
744 	switch (result) {
745 	case -EINVAL:
746 		return AE_BAD_PARAMETER;
747 		break;
748 	case -ENODEV:
749 		return AE_NOT_FOUND;
750 		break;
751 	case -ETIME:
752 		return AE_TIME;
753 		break;
754 	default:
755 		return AE_OK;
756 	}
757 }
758 
759 static void acpi_wmi_notify(struct acpi_device *device, u32 event)
760 {
761 	struct guid_block *block;
762 	struct wmi_block *wblock;
763 	struct list_head *p;
764 
765 	list_for_each(p, &wmi_block_list) {
766 		wblock = list_entry(p, struct wmi_block, list);
767 		block = &wblock->gblock;
768 
769 		if ((block->flags & ACPI_WMI_EVENT) &&
770 			(block->notify_id == event)) {
771 			if (wblock->handler)
772 				wblock->handler(event, wblock->handler_data);
773 			if (debug_event) {
774 				pr_info("DEBUG Event GUID: %pUL\n",
775 					wblock->gblock.guid);
776 			}
777 
778 			acpi_bus_generate_netlink_event(
779 				device->pnp.device_class, dev_name(&device->dev),
780 				event, 0);
781 			break;
782 		}
783 	}
784 }
785 
786 static int acpi_wmi_remove(struct acpi_device *device)
787 {
788 	acpi_remove_address_space_handler(device->handle,
789 				ACPI_ADR_SPACE_EC, &acpi_wmi_ec_space_handler);
790 	wmi_free_devices();
791 
792 	return 0;
793 }
794 
795 static int acpi_wmi_add(struct acpi_device *device)
796 {
797 	acpi_status status;
798 	int error;
799 
800 	status = acpi_install_address_space_handler(device->handle,
801 						    ACPI_ADR_SPACE_EC,
802 						    &acpi_wmi_ec_space_handler,
803 						    NULL, NULL);
804 	if (ACPI_FAILURE(status)) {
805 		pr_err("Error installing EC region handler\n");
806 		return -ENODEV;
807 	}
808 
809 	error = parse_wdg(device->handle);
810 	if (error) {
811 		acpi_remove_address_space_handler(device->handle,
812 						  ACPI_ADR_SPACE_EC,
813 						  &acpi_wmi_ec_space_handler);
814 		pr_err("Failed to parse WDG method\n");
815 		return error;
816 	}
817 
818 	return 0;
819 }
820 
821 static int __init acpi_wmi_init(void)
822 {
823 	int error;
824 
825 	if (acpi_disabled)
826 		return -ENODEV;
827 
828 	error = class_register(&wmi_class);
829 	if (error)
830 		return error;
831 
832 	error = acpi_bus_register_driver(&acpi_wmi_driver);
833 	if (error) {
834 		pr_err("Error loading mapper\n");
835 		class_unregister(&wmi_class);
836 		return error;
837 	}
838 
839 	pr_info("Mapper loaded\n");
840 	return 0;
841 }
842 
843 static void __exit acpi_wmi_exit(void)
844 {
845 	acpi_bus_unregister_driver(&acpi_wmi_driver);
846 	class_unregister(&wmi_class);
847 
848 	pr_info("Mapper unloaded\n");
849 }
850 
851 subsys_initcall(acpi_wmi_init);
852 module_exit(acpi_wmi_exit);
853