xref: /openbmc/linux/drivers/acpi/acpica/evgpe.c (revision 565d76cb)
1 /******************************************************************************
2  *
3  * Module Name: evgpe - General Purpose Event handling and dispatch
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2011, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions, and the following disclaimer,
16  *    without modification.
17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18  *    substantially similar to the "NO WARRANTY" disclaimer below
19  *    ("Disclaimer") and any redistribution must be conditioned upon
20  *    including a substantially similar Disclaimer requirement for further
21  *    binary redistribution.
22  * 3. Neither the names of the above-listed copyright holders nor the names
23  *    of any contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * Alternatively, this software may be distributed under the terms of the
27  * GNU General Public License ("GPL") version 2 as published by the Free
28  * Software Foundation.
29  *
30  * NO WARRANTY
31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGES.
42  */
43 
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "acevents.h"
47 #include "acnamesp.h"
48 
49 #define _COMPONENT          ACPI_EVENTS
50 ACPI_MODULE_NAME("evgpe")
51 
52 /* Local prototypes */
53 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context);
54 
55 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_enable_gpe(void *context);
56 
57 /*******************************************************************************
58  *
59  * FUNCTION:    acpi_ev_update_gpe_enable_mask
60  *
61  * PARAMETERS:  gpe_event_info          - GPE to update
62  *
63  * RETURN:      Status
64  *
65  * DESCRIPTION: Updates GPE register enable mask based upon whether there are
66  *              runtime references to this GPE
67  *
68  ******************************************************************************/
69 
70 acpi_status
71 acpi_ev_update_gpe_enable_mask(struct acpi_gpe_event_info *gpe_event_info)
72 {
73 	struct acpi_gpe_register_info *gpe_register_info;
74 	u32 register_bit;
75 
76 	ACPI_FUNCTION_TRACE(ev_update_gpe_enable_mask);
77 
78 	gpe_register_info = gpe_event_info->register_info;
79 	if (!gpe_register_info) {
80 		return_ACPI_STATUS(AE_NOT_EXIST);
81 	}
82 
83 	register_bit = acpi_hw_get_gpe_register_bit(gpe_event_info,
84 						gpe_register_info);
85 
86 	/* Clear the run bit up front */
87 
88 	ACPI_CLEAR_BIT(gpe_register_info->enable_for_run, register_bit);
89 
90 	/* Set the mask bit only if there are references to this GPE */
91 
92 	if (gpe_event_info->runtime_count) {
93 		ACPI_SET_BIT(gpe_register_info->enable_for_run, (u8)register_bit);
94 	}
95 
96 	return_ACPI_STATUS(AE_OK);
97 }
98 
99 /*******************************************************************************
100  *
101  * FUNCTION:    acpi_ev_enable_gpe
102  *
103  * PARAMETERS:  gpe_event_info  - GPE to enable
104  *
105  * RETURN:      Status
106  *
107  * DESCRIPTION: Clear a GPE of stale events and enable it.
108  *
109  ******************************************************************************/
110 acpi_status
111 acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
112 {
113 	acpi_status status;
114 
115 	ACPI_FUNCTION_TRACE(ev_enable_gpe);
116 
117 	/*
118 	 * We will only allow a GPE to be enabled if it has either an associated
119 	 * method (_Lxx/_Exx) or a handler, or is using the implicit notify
120 	 * feature. Otherwise, the GPE will be immediately disabled by
121 	 * acpi_ev_gpe_dispatch the first time it fires.
122 	 */
123 	if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
124 	    ACPI_GPE_DISPATCH_NONE) {
125 		return_ACPI_STATUS(AE_NO_HANDLER);
126 	}
127 
128 	/* Clear the GPE (of stale events) */
129 	status = acpi_hw_clear_gpe(gpe_event_info);
130 	if (ACPI_FAILURE(status)) {
131 		return_ACPI_STATUS(status);
132 	}
133 
134 	/* Enable the requested GPE */
135 	status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
136 
137 	return_ACPI_STATUS(status);
138 }
139 
140 
141 /*******************************************************************************
142  *
143  * FUNCTION:    acpi_ev_add_gpe_reference
144  *
145  * PARAMETERS:  gpe_event_info          - Add a reference to this GPE
146  *
147  * RETURN:      Status
148  *
149  * DESCRIPTION: Add a reference to a GPE. On the first reference, the GPE is
150  *              hardware-enabled.
151  *
152  ******************************************************************************/
153 
154 acpi_status acpi_ev_add_gpe_reference(struct acpi_gpe_event_info *gpe_event_info)
155 {
156 	acpi_status status = AE_OK;
157 
158 	ACPI_FUNCTION_TRACE(ev_add_gpe_reference);
159 
160 	if (gpe_event_info->runtime_count == ACPI_UINT8_MAX) {
161 		return_ACPI_STATUS(AE_LIMIT);
162 	}
163 
164 	gpe_event_info->runtime_count++;
165 	if (gpe_event_info->runtime_count == 1) {
166 
167 		/* Enable on first reference */
168 
169 		status = acpi_ev_update_gpe_enable_mask(gpe_event_info);
170 		if (ACPI_SUCCESS(status)) {
171 			status = acpi_ev_enable_gpe(gpe_event_info);
172 		}
173 
174 		if (ACPI_FAILURE(status)) {
175 			gpe_event_info->runtime_count--;
176 		}
177 	}
178 
179 	return_ACPI_STATUS(status);
180 }
181 
182 /*******************************************************************************
183  *
184  * FUNCTION:    acpi_ev_remove_gpe_reference
185  *
186  * PARAMETERS:  gpe_event_info          - Remove a reference to this GPE
187  *
188  * RETURN:      Status
189  *
190  * DESCRIPTION: Remove a reference to a GPE. When the last reference is
191  *              removed, the GPE is hardware-disabled.
192  *
193  ******************************************************************************/
194 
195 acpi_status acpi_ev_remove_gpe_reference(struct acpi_gpe_event_info *gpe_event_info)
196 {
197 	acpi_status status = AE_OK;
198 
199 	ACPI_FUNCTION_TRACE(ev_remove_gpe_reference);
200 
201 	if (!gpe_event_info->runtime_count) {
202 		return_ACPI_STATUS(AE_LIMIT);
203 	}
204 
205 	gpe_event_info->runtime_count--;
206 	if (!gpe_event_info->runtime_count) {
207 
208 		/* Disable on last reference */
209 
210 		status = acpi_ev_update_gpe_enable_mask(gpe_event_info);
211 		if (ACPI_SUCCESS(status)) {
212 			status = acpi_hw_low_set_gpe(gpe_event_info,
213 						     ACPI_GPE_DISABLE);
214 		}
215 
216 		if (ACPI_FAILURE(status)) {
217 			gpe_event_info->runtime_count++;
218 		}
219 	}
220 
221 	return_ACPI_STATUS(status);
222 }
223 
224 /*******************************************************************************
225  *
226  * FUNCTION:    acpi_ev_low_get_gpe_info
227  *
228  * PARAMETERS:  gpe_number          - Raw GPE number
229  *              gpe_block           - A GPE info block
230  *
231  * RETURN:      A GPE event_info struct. NULL if not a valid GPE (The gpe_number
232  *              is not within the specified GPE block)
233  *
234  * DESCRIPTION: Returns the event_info struct associated with this GPE. This is
235  *              the low-level implementation of ev_get_gpe_event_info.
236  *
237  ******************************************************************************/
238 
239 struct acpi_gpe_event_info *acpi_ev_low_get_gpe_info(u32 gpe_number,
240 						     struct acpi_gpe_block_info
241 						     *gpe_block)
242 {
243 	u32 gpe_index;
244 
245 	/*
246 	 * Validate that the gpe_number is within the specified gpe_block.
247 	 * (Two steps)
248 	 */
249 	if (!gpe_block || (gpe_number < gpe_block->block_base_number)) {
250 		return (NULL);
251 	}
252 
253 	gpe_index = gpe_number - gpe_block->block_base_number;
254 	if (gpe_index >= gpe_block->gpe_count) {
255 		return (NULL);
256 	}
257 
258 	return (&gpe_block->event_info[gpe_index]);
259 }
260 
261 
262 /*******************************************************************************
263  *
264  * FUNCTION:    acpi_ev_get_gpe_event_info
265  *
266  * PARAMETERS:  gpe_device          - Device node. NULL for GPE0/GPE1
267  *              gpe_number          - Raw GPE number
268  *
269  * RETURN:      A GPE event_info struct. NULL if not a valid GPE
270  *
271  * DESCRIPTION: Returns the event_info struct associated with this GPE.
272  *              Validates the gpe_block and the gpe_number
273  *
274  *              Should be called only when the GPE lists are semaphore locked
275  *              and not subject to change.
276  *
277  ******************************************************************************/
278 
279 struct acpi_gpe_event_info *acpi_ev_get_gpe_event_info(acpi_handle gpe_device,
280 						       u32 gpe_number)
281 {
282 	union acpi_operand_object *obj_desc;
283 	struct acpi_gpe_event_info *gpe_info;
284 	u32 i;
285 
286 	ACPI_FUNCTION_ENTRY();
287 
288 	/* A NULL gpe_device means use the FADT-defined GPE block(s) */
289 
290 	if (!gpe_device) {
291 
292 		/* Examine GPE Block 0 and 1 (These blocks are permanent) */
293 
294 		for (i = 0; i < ACPI_MAX_GPE_BLOCKS; i++) {
295 			gpe_info = acpi_ev_low_get_gpe_info(gpe_number,
296 							    acpi_gbl_gpe_fadt_blocks
297 							    [i]);
298 			if (gpe_info) {
299 				return (gpe_info);
300 			}
301 		}
302 
303 		/* The gpe_number was not in the range of either FADT GPE block */
304 
305 		return (NULL);
306 	}
307 
308 	/* A Non-NULL gpe_device means this is a GPE Block Device */
309 
310 	obj_desc = acpi_ns_get_attached_object((struct acpi_namespace_node *)
311 					       gpe_device);
312 	if (!obj_desc || !obj_desc->device.gpe_block) {
313 		return (NULL);
314 	}
315 
316 	return (acpi_ev_low_get_gpe_info
317 		(gpe_number, obj_desc->device.gpe_block));
318 }
319 
320 /*******************************************************************************
321  *
322  * FUNCTION:    acpi_ev_gpe_detect
323  *
324  * PARAMETERS:  gpe_xrupt_list      - Interrupt block for this interrupt.
325  *                                    Can have multiple GPE blocks attached.
326  *
327  * RETURN:      INTERRUPT_HANDLED or INTERRUPT_NOT_HANDLED
328  *
329  * DESCRIPTION: Detect if any GP events have occurred. This function is
330  *              executed at interrupt level.
331  *
332  ******************************************************************************/
333 
334 u32 acpi_ev_gpe_detect(struct acpi_gpe_xrupt_info * gpe_xrupt_list)
335 {
336 	acpi_status status;
337 	struct acpi_gpe_block_info *gpe_block;
338 	struct acpi_gpe_register_info *gpe_register_info;
339 	u32 int_status = ACPI_INTERRUPT_NOT_HANDLED;
340 	u8 enabled_status_byte;
341 	u32 status_reg;
342 	u32 enable_reg;
343 	acpi_cpu_flags flags;
344 	u32 i;
345 	u32 j;
346 
347 	ACPI_FUNCTION_NAME(ev_gpe_detect);
348 
349 	/* Check for the case where there are no GPEs */
350 
351 	if (!gpe_xrupt_list) {
352 		return (int_status);
353 	}
354 
355 	/*
356 	 * We need to obtain the GPE lock for both the data structs and registers
357 	 * Note: Not necessary to obtain the hardware lock, since the GPE
358 	 * registers are owned by the gpe_lock.
359 	 */
360 	flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
361 
362 	/* Examine all GPE blocks attached to this interrupt level */
363 
364 	gpe_block = gpe_xrupt_list->gpe_block_list_head;
365 	while (gpe_block) {
366 		/*
367 		 * Read all of the 8-bit GPE status and enable registers in this GPE
368 		 * block, saving all of them. Find all currently active GP events.
369 		 */
370 		for (i = 0; i < gpe_block->register_count; i++) {
371 
372 			/* Get the next status/enable pair */
373 
374 			gpe_register_info = &gpe_block->register_info[i];
375 
376 			/* Read the Status Register */
377 
378 			status =
379 			    acpi_hw_read(&status_reg,
380 					 &gpe_register_info->status_address);
381 			if (ACPI_FAILURE(status)) {
382 				goto unlock_and_exit;
383 			}
384 
385 			/* Read the Enable Register */
386 
387 			status =
388 			    acpi_hw_read(&enable_reg,
389 					 &gpe_register_info->enable_address);
390 			if (ACPI_FAILURE(status)) {
391 				goto unlock_and_exit;
392 			}
393 
394 			ACPI_DEBUG_PRINT((ACPI_DB_INTERRUPTS,
395 					  "Read GPE Register at GPE%02X: Status=%02X, Enable=%02X\n",
396 					  gpe_register_info->base_gpe_number,
397 					  status_reg, enable_reg));
398 
399 			/* Check if there is anything active at all in this register */
400 
401 			enabled_status_byte = (u8) (status_reg & enable_reg);
402 			if (!enabled_status_byte) {
403 
404 				/* No active GPEs in this register, move on */
405 
406 				continue;
407 			}
408 
409 			/* Now look at the individual GPEs in this byte register */
410 
411 			for (j = 0; j < ACPI_GPE_REGISTER_WIDTH; j++) {
412 
413 				/* Examine one GPE bit */
414 
415 				if (enabled_status_byte & (1 << j)) {
416 					/*
417 					 * Found an active GPE. Dispatch the event to a handler
418 					 * or method.
419 					 */
420 					int_status |=
421 					    acpi_ev_gpe_dispatch(gpe_block->
422 								 node,
423 								 &gpe_block->
424 						event_info[((acpi_size) i * ACPI_GPE_REGISTER_WIDTH) + j], j + gpe_register_info->base_gpe_number);
425 				}
426 			}
427 		}
428 
429 		gpe_block = gpe_block->next;
430 	}
431 
432       unlock_and_exit:
433 
434 	acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
435 	return (int_status);
436 }
437 
438 /*******************************************************************************
439  *
440  * FUNCTION:    acpi_ev_asynch_execute_gpe_method
441  *
442  * PARAMETERS:  Context (gpe_event_info) - Info for this GPE
443  *
444  * RETURN:      None
445  *
446  * DESCRIPTION: Perform the actual execution of a GPE control method. This
447  *              function is called from an invocation of acpi_os_execute and
448  *              therefore does NOT execute at interrupt level - so that
449  *              the control method itself is not executed in the context of
450  *              an interrupt handler.
451  *
452  ******************************************************************************/
453 
454 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
455 {
456 	struct acpi_gpe_event_info *gpe_event_info = context;
457 	acpi_status status;
458 	struct acpi_gpe_event_info *local_gpe_event_info;
459 	struct acpi_evaluate_info *info;
460 	struct acpi_gpe_notify_object *notify_object;
461 
462 	ACPI_FUNCTION_TRACE(ev_asynch_execute_gpe_method);
463 
464 	/* Allocate a local GPE block */
465 
466 	local_gpe_event_info =
467 	    ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_gpe_event_info));
468 	if (!local_gpe_event_info) {
469 		ACPI_EXCEPTION((AE_INFO, AE_NO_MEMORY, "while handling a GPE"));
470 		return_VOID;
471 	}
472 
473 	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
474 	if (ACPI_FAILURE(status)) {
475 		ACPI_FREE(local_gpe_event_info);
476 		return_VOID;
477 	}
478 
479 	/* Must revalidate the gpe_number/gpe_block */
480 
481 	if (!acpi_ev_valid_gpe_event(gpe_event_info)) {
482 		status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
483 		ACPI_FREE(local_gpe_event_info);
484 		return_VOID;
485 	}
486 
487 	/*
488 	 * Take a snapshot of the GPE info for this level - we copy the info to
489 	 * prevent a race condition with remove_handler/remove_block.
490 	 */
491 	ACPI_MEMCPY(local_gpe_event_info, gpe_event_info,
492 		    sizeof(struct acpi_gpe_event_info));
493 
494 	status = acpi_ut_release_mutex(ACPI_MTX_EVENTS);
495 	if (ACPI_FAILURE(status)) {
496 		return_VOID;
497 	}
498 
499 	/* Do the correct dispatch - normal method or implicit notify */
500 
501 	switch (local_gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
502 	case ACPI_GPE_DISPATCH_NOTIFY:
503 
504 		/*
505 		 * Implicit notify.
506 		 * Dispatch a DEVICE_WAKE notify to the appropriate handler.
507 		 * NOTE: the request is queued for execution after this method
508 		 * completes. The notify handlers are NOT invoked synchronously
509 		 * from this thread -- because handlers may in turn run other
510 		 * control methods.
511 		 */
512 		status = acpi_ev_queue_notify_request(
513 				local_gpe_event_info->dispatch.device.node,
514 				ACPI_NOTIFY_DEVICE_WAKE);
515 
516 		notify_object = local_gpe_event_info->dispatch.device.next;
517 		while (ACPI_SUCCESS(status) && notify_object) {
518 			status = acpi_ev_queue_notify_request(
519 					notify_object->node,
520 					ACPI_NOTIFY_DEVICE_WAKE);
521 			notify_object = notify_object->next;
522 		}
523 
524 		break;
525 
526 	case ACPI_GPE_DISPATCH_METHOD:
527 
528 		/* Allocate the evaluation information block */
529 
530 		info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
531 		if (!info) {
532 			status = AE_NO_MEMORY;
533 		} else {
534 			/*
535 			 * Invoke the GPE Method (_Lxx, _Exx) i.e., evaluate the _Lxx/_Exx
536 			 * control method that corresponds to this GPE
537 			 */
538 			info->prefix_node =
539 			    local_gpe_event_info->dispatch.method_node;
540 			info->flags = ACPI_IGNORE_RETURN_VALUE;
541 
542 			status = acpi_ns_evaluate(info);
543 			ACPI_FREE(info);
544 		}
545 
546 		if (ACPI_FAILURE(status)) {
547 			ACPI_EXCEPTION((AE_INFO, status,
548 					"while evaluating GPE method [%4.4s]",
549 					acpi_ut_get_node_name
550 					(local_gpe_event_info->dispatch.
551 					 method_node)));
552 		}
553 
554 		break;
555 
556 	default:
557 		return_VOID;    /* Should never happen */
558 	}
559 
560 	/* Defer enabling of GPE until all notify handlers are done */
561 
562 	status = acpi_os_execute(OSL_NOTIFY_HANDLER,
563 				 acpi_ev_asynch_enable_gpe,
564 				 local_gpe_event_info);
565 	if (ACPI_FAILURE(status)) {
566 		ACPI_FREE(local_gpe_event_info);
567 	}
568 	return_VOID;
569 }
570 
571 
572 /*******************************************************************************
573  *
574  * FUNCTION:    acpi_ev_asynch_enable_gpe
575  *
576  * PARAMETERS:  Context (gpe_event_info) - Info for this GPE
577  *              Callback from acpi_os_execute
578  *
579  * RETURN:      None
580  *
581  * DESCRIPTION: Asynchronous clear/enable for GPE. This allows the GPE to
582  *              complete (i.e., finish execution of Notify)
583  *
584  ******************************************************************************/
585 
586 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_enable_gpe(void *context)
587 {
588 	struct acpi_gpe_event_info *gpe_event_info = context;
589 
590 	(void)acpi_ev_finish_gpe(gpe_event_info);
591 
592 	ACPI_FREE(gpe_event_info);
593 	return;
594 }
595 
596 
597 /*******************************************************************************
598  *
599  * FUNCTION:    acpi_ev_finish_gpe
600  *
601  * PARAMETERS:  gpe_event_info      - Info for this GPE
602  *
603  * RETURN:      Status
604  *
605  * DESCRIPTION: Clear/Enable a GPE. Common code that is used after execution
606  *              of a GPE method or a synchronous or asynchronous GPE handler.
607  *
608  ******************************************************************************/
609 
610 acpi_status acpi_ev_finish_gpe(struct acpi_gpe_event_info *gpe_event_info)
611 {
612 	acpi_status status;
613 
614 	if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
615 	    ACPI_GPE_LEVEL_TRIGGERED) {
616 		/*
617 		 * GPE is level-triggered, we clear the GPE status bit after
618 		 * handling the event.
619 		 */
620 		status = acpi_hw_clear_gpe(gpe_event_info);
621 		if (ACPI_FAILURE(status)) {
622 			return (status);
623 		}
624 	}
625 
626 	/*
627 	 * Enable this GPE, conditionally. This means that the GPE will
628 	 * only be physically enabled if the enable_for_run bit is set
629 	 * in the event_info.
630 	 */
631 	(void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_CONDITIONAL_ENABLE);
632 	return (AE_OK);
633 }
634 
635 
636 /*******************************************************************************
637  *
638  * FUNCTION:    acpi_ev_gpe_dispatch
639  *
640  * PARAMETERS:  gpe_device      - Device node. NULL for GPE0/GPE1
641  *              gpe_event_info  - Info for this GPE
642  *              gpe_number      - Number relative to the parent GPE block
643  *
644  * RETURN:      INTERRUPT_HANDLED or INTERRUPT_NOT_HANDLED
645  *
646  * DESCRIPTION: Dispatch a General Purpose Event to either a function (e.g. EC)
647  *              or method (e.g. _Lxx/_Exx) handler.
648  *
649  *              This function executes at interrupt level.
650  *
651  ******************************************************************************/
652 
653 u32
654 acpi_ev_gpe_dispatch(struct acpi_namespace_node *gpe_device,
655 		    struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
656 {
657 	acpi_status status;
658 	u32 return_value;
659 
660 	ACPI_FUNCTION_TRACE(ev_gpe_dispatch);
661 
662 	/* Invoke global event handler if present */
663 
664 	acpi_gpe_count++;
665 	if (acpi_gbl_global_event_handler) {
666 		acpi_gbl_global_event_handler(ACPI_EVENT_TYPE_GPE, gpe_device,
667 					      gpe_number,
668 					      acpi_gbl_global_event_handler_context);
669 	}
670 
671 	/*
672 	 * If edge-triggered, clear the GPE status bit now. Note that
673 	 * level-triggered events are cleared after the GPE is serviced.
674 	 */
675 	if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
676 	    ACPI_GPE_EDGE_TRIGGERED) {
677 		status = acpi_hw_clear_gpe(gpe_event_info);
678 		if (ACPI_FAILURE(status)) {
679 			ACPI_EXCEPTION((AE_INFO, status,
680 					"Unable to clear GPE%02X", gpe_number));
681 			return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
682 		}
683 	}
684 
685 	/*
686 	 * Always disable the GPE so that it does not keep firing before
687 	 * any asynchronous activity completes (either from the execution
688 	 * of a GPE method or an asynchronous GPE handler.)
689 	 *
690 	 * If there is no handler or method to run, just disable the
691 	 * GPE and leave it disabled permanently to prevent further such
692 	 * pointless events from firing.
693 	 */
694 	status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
695 	if (ACPI_FAILURE(status)) {
696 		ACPI_EXCEPTION((AE_INFO, status,
697 				"Unable to disable GPE%02X", gpe_number));
698 		return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
699 	}
700 
701 	/*
702 	 * Dispatch the GPE to either an installed handler or the control
703 	 * method associated with this GPE (_Lxx or _Exx). If a handler
704 	 * exists, we invoke it and do not attempt to run the method.
705 	 * If there is neither a handler nor a method, leave the GPE
706 	 * disabled.
707 	 */
708 	switch (gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
709 	case ACPI_GPE_DISPATCH_HANDLER:
710 
711 		/* Invoke the installed handler (at interrupt level) */
712 
713 		return_value =
714 		    gpe_event_info->dispatch.handler->address(gpe_device,
715 							      gpe_number,
716 							      gpe_event_info->
717 							      dispatch.handler->
718 							      context);
719 
720 		/* If requested, clear (if level-triggered) and reenable the GPE */
721 
722 		if (return_value & ACPI_REENABLE_GPE) {
723 			(void)acpi_ev_finish_gpe(gpe_event_info);
724 		}
725 		break;
726 
727 	case ACPI_GPE_DISPATCH_METHOD:
728 	case ACPI_GPE_DISPATCH_NOTIFY:
729 
730 		/*
731 		 * Execute the method associated with the GPE
732 		 * NOTE: Level-triggered GPEs are cleared after the method completes.
733 		 */
734 		status = acpi_os_execute(OSL_GPE_HANDLER,
735 					 acpi_ev_asynch_execute_gpe_method,
736 					 gpe_event_info);
737 		if (ACPI_FAILURE(status)) {
738 			ACPI_EXCEPTION((AE_INFO, status,
739 					"Unable to queue handler for GPE%2X - event disabled",
740 					gpe_number));
741 		}
742 		break;
743 
744 	default:
745 
746 		/*
747 		 * No handler or method to run!
748 		 * 03/2010: This case should no longer be possible. We will not allow
749 		 * a GPE to be enabled if it has no handler or method.
750 		 */
751 		ACPI_ERROR((AE_INFO,
752 			    "No handler or method for GPE%02X, disabling event",
753 			    gpe_number));
754 
755 		break;
756 	}
757 
758 	return_UINT32(ACPI_INTERRUPT_HANDLED);
759 }
760