xref: /linux/drivers/acpi/acpica/evgpeinit.c (revision 5d4a2e29fba5b2bef95b96a46b338ec4d76fa4fd)
1 /******************************************************************************
2  *
3  * Module Name: evgpeinit - System GPE initialization and update
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2010, 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 #include "acinterp.h"
49 
50 #define _COMPONENT          ACPI_EVENTS
51 ACPI_MODULE_NAME("evgpeinit")
52 
53 /*******************************************************************************
54  *
55  * FUNCTION:    acpi_ev_gpe_initialize
56  *
57  * PARAMETERS:  None
58  *
59  * RETURN:      Status
60  *
61  * DESCRIPTION: Initialize the GPE data structures and the FADT GPE 0/1 blocks
62  *
63  ******************************************************************************/
64 acpi_status acpi_ev_gpe_initialize(void)
65 {
66 	u32 register_count0 = 0;
67 	u32 register_count1 = 0;
68 	u32 gpe_number_max = 0;
69 	acpi_status status;
70 
71 	ACPI_FUNCTION_TRACE(ev_gpe_initialize);
72 
73 	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
74 	if (ACPI_FAILURE(status)) {
75 		return_ACPI_STATUS(status);
76 	}
77 
78 	/*
79 	 * Initialize the GPE Block(s) defined in the FADT
80 	 *
81 	 * Why the GPE register block lengths are divided by 2:  From the ACPI
82 	 * Spec, section "General-Purpose Event Registers", we have:
83 	 *
84 	 * "Each register block contains two registers of equal length
85 	 *  GPEx_STS and GPEx_EN (where x is 0 or 1). The length of the
86 	 *  GPE0_STS and GPE0_EN registers is equal to half the GPE0_LEN
87 	 *  The length of the GPE1_STS and GPE1_EN registers is equal to
88 	 *  half the GPE1_LEN. If a generic register block is not supported
89 	 *  then its respective block pointer and block length values in the
90 	 *  FADT table contain zeros. The GPE0_LEN and GPE1_LEN do not need
91 	 *  to be the same size."
92 	 */
93 
94 	/*
95 	 * Determine the maximum GPE number for this machine.
96 	 *
97 	 * Note: both GPE0 and GPE1 are optional, and either can exist without
98 	 * the other.
99 	 *
100 	 * If EITHER the register length OR the block address are zero, then that
101 	 * particular block is not supported.
102 	 */
103 	if (acpi_gbl_FADT.gpe0_block_length &&
104 	    acpi_gbl_FADT.xgpe0_block.address) {
105 
106 		/* GPE block 0 exists (has both length and address > 0) */
107 
108 		register_count0 = (u16)(acpi_gbl_FADT.gpe0_block_length / 2);
109 
110 		gpe_number_max =
111 		    (register_count0 * ACPI_GPE_REGISTER_WIDTH) - 1;
112 
113 		/* Install GPE Block 0 */
114 
115 		status = acpi_ev_create_gpe_block(acpi_gbl_fadt_gpe_device,
116 						  &acpi_gbl_FADT.xgpe0_block,
117 						  register_count0, 0,
118 						  acpi_gbl_FADT.sci_interrupt,
119 						  &acpi_gbl_gpe_fadt_blocks[0]);
120 
121 		if (ACPI_FAILURE(status)) {
122 			ACPI_EXCEPTION((AE_INFO, status,
123 					"Could not create GPE Block 0"));
124 		}
125 	}
126 
127 	if (acpi_gbl_FADT.gpe1_block_length &&
128 	    acpi_gbl_FADT.xgpe1_block.address) {
129 
130 		/* GPE block 1 exists (has both length and address > 0) */
131 
132 		register_count1 = (u16)(acpi_gbl_FADT.gpe1_block_length / 2);
133 
134 		/* Check for GPE0/GPE1 overlap (if both banks exist) */
135 
136 		if ((register_count0) &&
137 		    (gpe_number_max >= acpi_gbl_FADT.gpe1_base)) {
138 			ACPI_ERROR((AE_INFO,
139 				    "GPE0 block (GPE 0 to %u) overlaps the GPE1 block "
140 				    "(GPE %u to %u) - Ignoring GPE1",
141 				    gpe_number_max, acpi_gbl_FADT.gpe1_base,
142 				    acpi_gbl_FADT.gpe1_base +
143 				    ((register_count1 *
144 				      ACPI_GPE_REGISTER_WIDTH) - 1)));
145 
146 			/* Ignore GPE1 block by setting the register count to zero */
147 
148 			register_count1 = 0;
149 		} else {
150 			/* Install GPE Block 1 */
151 
152 			status =
153 			    acpi_ev_create_gpe_block(acpi_gbl_fadt_gpe_device,
154 						     &acpi_gbl_FADT.xgpe1_block,
155 						     register_count1,
156 						     acpi_gbl_FADT.gpe1_base,
157 						     acpi_gbl_FADT.
158 						     sci_interrupt,
159 						     &acpi_gbl_gpe_fadt_blocks
160 						     [1]);
161 
162 			if (ACPI_FAILURE(status)) {
163 				ACPI_EXCEPTION((AE_INFO, status,
164 						"Could not create GPE Block 1"));
165 			}
166 
167 			/*
168 			 * GPE0 and GPE1 do not have to be contiguous in the GPE number
169 			 * space. However, GPE0 always starts at GPE number zero.
170 			 */
171 			gpe_number_max = acpi_gbl_FADT.gpe1_base +
172 			    ((register_count1 * ACPI_GPE_REGISTER_WIDTH) - 1);
173 		}
174 	}
175 
176 	/* Exit if there are no GPE registers */
177 
178 	if ((register_count0 + register_count1) == 0) {
179 
180 		/* GPEs are not required by ACPI, this is OK */
181 
182 		ACPI_DEBUG_PRINT((ACPI_DB_INIT,
183 				  "There are no GPE blocks defined in the FADT\n"));
184 		status = AE_OK;
185 		goto cleanup;
186 	}
187 
188 	/* Check for Max GPE number out-of-range */
189 
190 	if (gpe_number_max > ACPI_GPE_MAX) {
191 		ACPI_ERROR((AE_INFO,
192 			    "Maximum GPE number from FADT is too large: 0x%X",
193 			    gpe_number_max));
194 		status = AE_BAD_VALUE;
195 		goto cleanup;
196 	}
197 
198       cleanup:
199 	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
200 	return_ACPI_STATUS(AE_OK);
201 }
202 
203 /*******************************************************************************
204  *
205  * FUNCTION:    acpi_ev_update_gpes
206  *
207  * PARAMETERS:  table_owner_id      - ID of the newly-loaded ACPI table
208  *
209  * RETURN:      None
210  *
211  * DESCRIPTION: Check for new GPE methods (_Lxx/_Exx) made available as a
212  *              result of a Load() or load_table() operation. If new GPE
213  *              methods have been installed, register the new methods and
214  *              enable and runtime GPEs that are associated with them. Also,
215  *              run any newly loaded _PRW methods in order to discover any
216  *              new CAN_WAKE GPEs.
217  *
218  ******************************************************************************/
219 
220 void acpi_ev_update_gpes(acpi_owner_id table_owner_id)
221 {
222 	struct acpi_gpe_xrupt_info *gpe_xrupt_info;
223 	struct acpi_gpe_block_info *gpe_block;
224 	struct acpi_gpe_walk_info walk_info;
225 	acpi_status status = AE_OK;
226 	u32 new_wake_gpe_count = 0;
227 
228 	/* We will examine only _PRW/_Lxx/_Exx methods owned by this table */
229 
230 	walk_info.owner_id = table_owner_id;
231 	walk_info.execute_by_owner_id = TRUE;
232 	walk_info.count = 0;
233 
234 	if (acpi_gbl_leave_wake_gpes_disabled) {
235 		/*
236 		 * 1) Run any newly-loaded _PRW methods to find any GPEs that
237 		 * can now be marked as CAN_WAKE GPEs. Note: We must run the
238 		 * _PRW methods before we process the _Lxx/_Exx methods because
239 		 * we will enable all runtime GPEs associated with the new
240 		 * _Lxx/_Exx methods at the time we process those methods.
241 		 *
242 		 * Unlock interpreter so that we can run the _PRW methods.
243 		 */
244 		walk_info.gpe_block = NULL;
245 		walk_info.gpe_device = NULL;
246 
247 		acpi_ex_exit_interpreter();
248 
249 		status =
250 		    acpi_ns_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
251 					   ACPI_UINT32_MAX,
252 					   ACPI_NS_WALK_NO_UNLOCK,
253 					   acpi_ev_match_prw_and_gpe, NULL,
254 					   &walk_info, NULL);
255 		if (ACPI_FAILURE(status)) {
256 			ACPI_EXCEPTION((AE_INFO, status,
257 					"While executing _PRW methods"));
258 		}
259 
260 		acpi_ex_enter_interpreter();
261 		new_wake_gpe_count = walk_info.count;
262 	}
263 
264 	/*
265 	 * 2) Find any _Lxx/_Exx GPE methods that have just been loaded.
266 	 *
267 	 * Any GPEs that correspond to new _Lxx/_Exx methods and are not
268 	 * marked as CAN_WAKE are immediately enabled.
269 	 *
270 	 * Examine the namespace underneath each gpe_device within the
271 	 * gpe_block lists.
272 	 */
273 	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
274 	if (ACPI_FAILURE(status)) {
275 		return;
276 	}
277 
278 	walk_info.count = 0;
279 	walk_info.enable_this_gpe = TRUE;
280 
281 	/* Walk the interrupt level descriptor list */
282 
283 	gpe_xrupt_info = acpi_gbl_gpe_xrupt_list_head;
284 	while (gpe_xrupt_info) {
285 
286 		/* Walk all Gpe Blocks attached to this interrupt level */
287 
288 		gpe_block = gpe_xrupt_info->gpe_block_list_head;
289 		while (gpe_block) {
290 			walk_info.gpe_block = gpe_block;
291 			walk_info.gpe_device = gpe_block->node;
292 
293 			status = acpi_ns_walk_namespace(ACPI_TYPE_METHOD,
294 							walk_info.gpe_device,
295 							ACPI_UINT32_MAX,
296 							ACPI_NS_WALK_NO_UNLOCK,
297 							acpi_ev_match_gpe_method,
298 							NULL, &walk_info, NULL);
299 			if (ACPI_FAILURE(status)) {
300 				ACPI_EXCEPTION((AE_INFO, status,
301 						"While decoding _Lxx/_Exx methods"));
302 			}
303 
304 			gpe_block = gpe_block->next;
305 		}
306 
307 		gpe_xrupt_info = gpe_xrupt_info->next;
308 	}
309 
310 	if (walk_info.count || new_wake_gpe_count) {
311 		ACPI_INFO((AE_INFO,
312 			   "Enabled %u new runtime GPEs, added %u new wakeup GPEs",
313 			   walk_info.count, new_wake_gpe_count));
314 	}
315 
316 	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
317 	return;
318 }
319 
320 /*******************************************************************************
321  *
322  * FUNCTION:    acpi_ev_match_gpe_method
323  *
324  * PARAMETERS:  Callback from walk_namespace
325  *
326  * RETURN:      Status
327  *
328  * DESCRIPTION: Called from acpi_walk_namespace. Expects each object to be a
329  *              control method under the _GPE portion of the namespace.
330  *              Extract the name and GPE type from the object, saving this
331  *              information for quick lookup during GPE dispatch. Allows a
332  *              per-owner_id evaluation if execute_by_owner_id is TRUE in the
333  *              walk_info parameter block.
334  *
335  *              The name of each GPE control method is of the form:
336  *              "_Lxx" or "_Exx", where:
337  *                  L      - means that the GPE is level triggered
338  *                  E      - means that the GPE is edge triggered
339  *                  xx     - is the GPE number [in HEX]
340  *
341  * If walk_info->execute_by_owner_id is TRUE, we only execute examine GPE methods
342  *    with that owner.
343  * If walk_info->enable_this_gpe is TRUE, the GPE that is referred to by a GPE
344  *    method is immediately enabled (Used for Load/load_table operators)
345  *
346  ******************************************************************************/
347 
348 acpi_status
349 acpi_ev_match_gpe_method(acpi_handle obj_handle,
350 			 u32 level, void *context, void **return_value)
351 {
352 	struct acpi_namespace_node *method_node =
353 	    ACPI_CAST_PTR(struct acpi_namespace_node, obj_handle);
354 	struct acpi_gpe_walk_info *walk_info =
355 	    ACPI_CAST_PTR(struct acpi_gpe_walk_info, context);
356 	struct acpi_gpe_event_info *gpe_event_info;
357 	struct acpi_namespace_node *gpe_device;
358 	acpi_status status;
359 	u32 gpe_number;
360 	char name[ACPI_NAME_SIZE + 1];
361 	u8 type;
362 
363 	ACPI_FUNCTION_TRACE(ev_match_gpe_method);
364 
365 	/* Check if requested owner_id matches this owner_id */
366 
367 	if ((walk_info->execute_by_owner_id) &&
368 	    (method_node->owner_id != walk_info->owner_id)) {
369 		return_ACPI_STATUS(AE_OK);
370 	}
371 
372 	/*
373 	 * Match and decode the _Lxx and _Exx GPE method names
374 	 *
375 	 * 1) Extract the method name and null terminate it
376 	 */
377 	ACPI_MOVE_32_TO_32(name, &method_node->name.integer);
378 	name[ACPI_NAME_SIZE] = 0;
379 
380 	/* 2) Name must begin with an underscore */
381 
382 	if (name[0] != '_') {
383 		return_ACPI_STATUS(AE_OK);	/* Ignore this method */
384 	}
385 
386 	/*
387 	 * 3) Edge/Level determination is based on the 2nd character
388 	 *    of the method name
389 	 *
390 	 * NOTE: Default GPE type is RUNTIME only. Later, if a _PRW object is
391 	 * found that points to this GPE, the ACPI_GPE_CAN_WAKE flag is set.
392 	 */
393 	switch (name[1]) {
394 	case 'L':
395 		type = ACPI_GPE_LEVEL_TRIGGERED;
396 		break;
397 
398 	case 'E':
399 		type = ACPI_GPE_EDGE_TRIGGERED;
400 		break;
401 
402 	default:
403 		/* Unknown method type, just ignore it */
404 
405 		ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
406 				  "Ignoring unknown GPE method type: %s "
407 				  "(name not of form _Lxx or _Exx)", name));
408 		return_ACPI_STATUS(AE_OK);
409 	}
410 
411 	/* 4) The last two characters of the name are the hex GPE Number */
412 
413 	gpe_number = ACPI_STRTOUL(&name[2], NULL, 16);
414 	if (gpe_number == ACPI_UINT32_MAX) {
415 
416 		/* Conversion failed; invalid method, just ignore it */
417 
418 		ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
419 				  "Could not extract GPE number from name: %s "
420 				  "(name is not of form _Lxx or _Exx)", name));
421 		return_ACPI_STATUS(AE_OK);
422 	}
423 
424 	/* Ensure that we have a valid GPE number for this GPE block */
425 
426 	gpe_event_info =
427 	    acpi_ev_low_get_gpe_info(gpe_number, walk_info->gpe_block);
428 	if (!gpe_event_info) {
429 		/*
430 		 * This gpe_number is not valid for this GPE block, just ignore it.
431 		 * However, it may be valid for a different GPE block, since GPE0
432 		 * and GPE1 methods both appear under \_GPE.
433 		 */
434 		return_ACPI_STATUS(AE_OK);
435 	}
436 
437 	if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
438 	    ACPI_GPE_DISPATCH_HANDLER) {
439 
440 		/* If there is already a handler, ignore this GPE method */
441 
442 		return_ACPI_STATUS(AE_OK);
443 	}
444 
445 	if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
446 	    ACPI_GPE_DISPATCH_METHOD) {
447 		/*
448 		 * If there is already a method, ignore this method. But check
449 		 * for a type mismatch (if both the _Lxx AND _Exx exist)
450 		 */
451 		if (type != (gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK)) {
452 			ACPI_ERROR((AE_INFO,
453 				    "For GPE 0x%.2X, found both _L%2.2X and _E%2.2X methods",
454 				    gpe_number, gpe_number, gpe_number));
455 		}
456 		return_ACPI_STATUS(AE_OK);
457 	}
458 
459 	/*
460 	 * Add the GPE information from above to the gpe_event_info block for
461 	 * use during dispatch of this GPE.
462 	 */
463 	gpe_event_info->flags |= (u8)(type | ACPI_GPE_DISPATCH_METHOD);
464 	gpe_event_info->dispatch.method_node = method_node;
465 
466 	/*
467 	 * Enable this GPE if requested. This only happens when during the
468 	 * execution of a Load or load_table operator. We have found a new
469 	 * GPE method and want to immediately enable the GPE if it is a
470 	 * runtime GPE.
471 	 */
472 	if (walk_info->enable_this_gpe) {
473 
474 		/* Ignore GPEs that can wake the system */
475 
476 		if (!(gpe_event_info->flags & ACPI_GPE_CAN_WAKE) ||
477 		    !acpi_gbl_leave_wake_gpes_disabled) {
478 			walk_info->count++;
479 			gpe_device = walk_info->gpe_device;
480 
481 			if (gpe_device == acpi_gbl_fadt_gpe_device) {
482 				gpe_device = NULL;
483 			}
484 
485 			status = acpi_enable_gpe(gpe_device, gpe_number,
486 						 ACPI_GPE_TYPE_RUNTIME);
487 			if (ACPI_FAILURE(status)) {
488 				ACPI_EXCEPTION((AE_INFO, status,
489 						"Could not enable GPE 0x%02X",
490 						gpe_number));
491 			}
492 		}
493 	}
494 
495 	ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
496 			  "Registered GPE method %s as GPE number 0x%.2X\n",
497 			  name, gpe_number));
498 	return_ACPI_STATUS(AE_OK);
499 }
500 
501 /*******************************************************************************
502  *
503  * FUNCTION:    acpi_ev_match_prw_and_gpe
504  *
505  * PARAMETERS:  Callback from walk_namespace
506  *
507  * RETURN:      Status. NOTE: We ignore errors so that the _PRW walk is
508  *              not aborted on a single _PRW failure.
509  *
510  * DESCRIPTION: Called from acpi_walk_namespace. Expects each object to be a
511  *              Device. Run the _PRW method. If present, extract the GPE
512  *              number and mark the GPE as a CAN_WAKE GPE. Allows a
513  *              per-owner_id execution if execute_by_owner_id is TRUE in the
514  *              walk_info parameter block.
515  *
516  * If walk_info->execute_by_owner_id is TRUE, we only execute _PRWs with that
517  *    owner.
518  * If walk_info->gpe_device is NULL, we execute every _PRW found. Otherwise,
519  *    we only execute _PRWs that refer to the input gpe_device.
520  *
521  ******************************************************************************/
522 
523 acpi_status
524 acpi_ev_match_prw_and_gpe(acpi_handle obj_handle,
525 			  u32 level, void *context, void **return_value)
526 {
527 	struct acpi_gpe_walk_info *walk_info =
528 	    ACPI_CAST_PTR(struct acpi_gpe_walk_info, context);
529 	struct acpi_namespace_node *gpe_device;
530 	struct acpi_gpe_block_info *gpe_block;
531 	struct acpi_namespace_node *target_gpe_device;
532 	struct acpi_namespace_node *prw_node;
533 	struct acpi_gpe_event_info *gpe_event_info;
534 	union acpi_operand_object *pkg_desc;
535 	union acpi_operand_object *obj_desc;
536 	u32 gpe_number;
537 	acpi_status status;
538 
539 	ACPI_FUNCTION_TRACE(ev_match_prw_and_gpe);
540 
541 	/* Check for a _PRW method under this device */
542 
543 	status = acpi_ns_get_node(obj_handle, METHOD_NAME__PRW,
544 				  ACPI_NS_NO_UPSEARCH, &prw_node);
545 	if (ACPI_FAILURE(status)) {
546 		return_ACPI_STATUS(AE_OK);
547 	}
548 
549 	/* Check if requested owner_id matches this owner_id */
550 
551 	if ((walk_info->execute_by_owner_id) &&
552 	    (prw_node->owner_id != walk_info->owner_id)) {
553 		return_ACPI_STATUS(AE_OK);
554 	}
555 
556 	/* Execute the _PRW */
557 
558 	status = acpi_ut_evaluate_object(prw_node, NULL,
559 					 ACPI_BTYPE_PACKAGE, &pkg_desc);
560 	if (ACPI_FAILURE(status)) {
561 		return_ACPI_STATUS(AE_OK);
562 	}
563 
564 	/* The returned _PRW package must have at least two elements */
565 
566 	if (pkg_desc->package.count < 2) {
567 		goto cleanup;
568 	}
569 
570 	/* Extract pointers from the input context */
571 
572 	gpe_device = walk_info->gpe_device;
573 	gpe_block = walk_info->gpe_block;
574 
575 	/*
576 	 * The _PRW object must return a package, we are only interested
577 	 * in the first element
578 	 */
579 	obj_desc = pkg_desc->package.elements[0];
580 
581 	if (obj_desc->common.type == ACPI_TYPE_INTEGER) {
582 
583 		/* Use FADT-defined GPE device (from definition of _PRW) */
584 
585 		target_gpe_device = NULL;
586 		if (gpe_device) {
587 			target_gpe_device = acpi_gbl_fadt_gpe_device;
588 		}
589 
590 		/* Integer is the GPE number in the FADT described GPE blocks */
591 
592 		gpe_number = (u32)obj_desc->integer.value;
593 	} else if (obj_desc->common.type == ACPI_TYPE_PACKAGE) {
594 
595 		/* Package contains a GPE reference and GPE number within a GPE block */
596 
597 		if ((obj_desc->package.count < 2) ||
598 		    ((obj_desc->package.elements[0])->common.type !=
599 		     ACPI_TYPE_LOCAL_REFERENCE) ||
600 		    ((obj_desc->package.elements[1])->common.type !=
601 		     ACPI_TYPE_INTEGER)) {
602 			goto cleanup;
603 		}
604 
605 		/* Get GPE block reference and decode */
606 
607 		target_gpe_device =
608 		    obj_desc->package.elements[0]->reference.node;
609 		gpe_number = (u32)obj_desc->package.elements[1]->integer.value;
610 	} else {
611 		/* Unknown type, just ignore it */
612 
613 		goto cleanup;
614 	}
615 
616 	/* Get the gpe_event_info for this GPE */
617 
618 	if (gpe_device) {
619 		/*
620 		 * Is this GPE within this block?
621 		 *
622 		 * TRUE if and only if these conditions are true:
623 		 *     1) The GPE devices match.
624 		 *     2) The GPE index(number) is within the range of the Gpe Block
625 		 *          associated with the GPE device.
626 		 */
627 		if (gpe_device != target_gpe_device) {
628 			goto cleanup;
629 		}
630 
631 		gpe_event_info =
632 		    acpi_ev_low_get_gpe_info(gpe_number, gpe_block);
633 	} else {
634 		/* gpe_device is NULL, just match the target_device and gpe_number */
635 
636 		gpe_event_info =
637 		    acpi_ev_get_gpe_event_info(target_gpe_device, gpe_number);
638 	}
639 
640 	if (gpe_event_info) {
641 		if (!(gpe_event_info->flags & ACPI_GPE_CAN_WAKE)) {
642 
643 			/* This GPE can wake the system */
644 
645 			gpe_event_info->flags |= ACPI_GPE_CAN_WAKE;
646 			walk_info->count++;
647 		}
648 	}
649 
650       cleanup:
651 	acpi_ut_remove_reference(pkg_desc);
652 	return_ACPI_STATUS(AE_OK);
653 }
654