xref: /linux/drivers/acpi/ec.c (revision 98366c20a275e957416e9516db5dcb7195b4e101)
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v2.0)
3  *
4  *  Copyright (C) 2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
5  *  Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@intel.com>
6  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
7  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
8  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
9  *
10  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
11  *
12  *  This program is free software; you can redistribute it and/or modify
13  *  it under the terms of the GNU General Public License as published by
14  *  the Free Software Foundation; either version 2 of the License, or (at
15  *  your option) any later version.
16  *
17  *  This program is distributed in the hope that it will be useful, but
18  *  WITHOUT ANY WARRANTY; without even the implied warranty of
19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  *  General Public License for more details.
21  *
22  *  You should have received a copy of the GNU General Public License along
23  *  with this program; if not, write to the Free Software Foundation, Inc.,
24  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25  *
26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27  */
28 
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/types.h>
33 #include <linux/delay.h>
34 #include <linux/proc_fs.h>
35 #include <linux/seq_file.h>
36 #include <linux/interrupt.h>
37 #include <linux/list.h>
38 #include <asm/io.h>
39 #include <acpi/acpi_bus.h>
40 #include <acpi/acpi_drivers.h>
41 #include <acpi/actypes.h>
42 
43 #define ACPI_EC_CLASS			"embedded_controller"
44 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
45 #define ACPI_EC_FILE_INFO		"info"
46 
47 #undef PREFIX
48 #define PREFIX				"ACPI: EC: "
49 
50 /* EC status register */
51 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
52 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
53 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
54 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
55 
56 /* EC commands */
57 enum ec_command {
58 	ACPI_EC_COMMAND_READ = 0x80,
59 	ACPI_EC_COMMAND_WRITE = 0x81,
60 	ACPI_EC_BURST_ENABLE = 0x82,
61 	ACPI_EC_BURST_DISABLE = 0x83,
62 	ACPI_EC_COMMAND_QUERY = 0x84,
63 };
64 
65 /* EC events */
66 enum ec_event {
67 	ACPI_EC_EVENT_OBF_1 = 1,	/* Output buffer full */
68 	ACPI_EC_EVENT_IBF_0,		/* Input buffer empty */
69 };
70 
71 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
72 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
73 
74 enum {
75 	EC_FLAGS_WAIT_GPE = 0,		/* Don't check status until GPE arrives */
76 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
77 	EC_FLAGS_GPE_MODE,		/* Expect GPE to be sent for status change */
78 	EC_FLAGS_ONLY_IBF_GPE,		/* Expect GPE only for IBF = 0 event */
79 };
80 
81 static int acpi_ec_remove(struct acpi_device *device, int type);
82 static int acpi_ec_start(struct acpi_device *device);
83 static int acpi_ec_stop(struct acpi_device *device, int type);
84 static int acpi_ec_add(struct acpi_device *device);
85 
86 static const struct acpi_device_id ec_device_ids[] = {
87 	{"PNP0C09", 0},
88 	{"", 0},
89 };
90 
91 static struct acpi_driver acpi_ec_driver = {
92 	.name = "ec",
93 	.class = ACPI_EC_CLASS,
94 	.ids = ec_device_ids,
95 	.ops = {
96 		.add = acpi_ec_add,
97 		.remove = acpi_ec_remove,
98 		.start = acpi_ec_start,
99 		.stop = acpi_ec_stop,
100 		},
101 };
102 
103 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
104 /* External interfaces use first EC only, so remember */
105 typedef int (*acpi_ec_query_func) (void *data);
106 
107 struct acpi_ec_query_handler {
108 	struct list_head node;
109 	acpi_ec_query_func func;
110 	acpi_handle handle;
111 	void *data;
112 	u8 query_bit;
113 };
114 
115 static struct acpi_ec {
116 	acpi_handle handle;
117 	unsigned long gpe;
118 	unsigned long command_addr;
119 	unsigned long data_addr;
120 	unsigned long global_lock;
121 	unsigned long flags;
122 	struct mutex lock;
123 	wait_queue_head_t wait;
124 	struct list_head list;
125 	u8 handlers_installed;
126 } *boot_ec, *first_ec;
127 
128 /* --------------------------------------------------------------------------
129                              Transaction Management
130    -------------------------------------------------------------------------- */
131 
132 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
133 {
134 	return inb(ec->command_addr);
135 }
136 
137 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
138 {
139 	return inb(ec->data_addr);
140 }
141 
142 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
143 {
144 	outb(command, ec->command_addr);
145 }
146 
147 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
148 {
149 	outb(data, ec->data_addr);
150 }
151 
152 static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)
153 {
154 	if (test_bit(EC_FLAGS_WAIT_GPE, &ec->flags))
155 		return 0;
156 	if (event == ACPI_EC_EVENT_OBF_1) {
157 		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
158 			return 1;
159 	} else if (event == ACPI_EC_EVENT_IBF_0) {
160 		if (!(acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF))
161 			return 1;
162 	}
163 
164 	return 0;
165 }
166 
167 static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll)
168 {
169 	if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) &&
170 	    likely(!force_poll)) {
171 		if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event),
172 				       msecs_to_jiffies(ACPI_EC_DELAY)))
173 			return 0;
174 		clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
175 		if (acpi_ec_check_status(ec, event)) {
176 			if (event == ACPI_EC_EVENT_OBF_1) {
177 				/* miss OBF = 1 GPE, don't expect it anymore */
178 				printk(KERN_INFO PREFIX "missing OBF_1 confirmation,"
179 					"switching to degraded mode.\n");
180 				set_bit(EC_FLAGS_ONLY_IBF_GPE, &ec->flags);
181 			} else {
182 				/* missing GPEs, switch back to poll mode */
183 				printk(KERN_INFO PREFIX "missing IBF_1 confirmations,"
184 					"switch off interrupt mode.\n");
185 				clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
186 			}
187 			return 0;
188 		}
189 	} else {
190 		unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
191 		clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
192 		while (time_before(jiffies, delay)) {
193 			if (acpi_ec_check_status(ec, event))
194 				return 0;
195 		}
196 	}
197 	printk(KERN_ERR PREFIX "acpi_ec_wait timeout,"
198 			       " status = %d, expect_event = %d\n",
199 			       acpi_ec_read_status(ec), event);
200 	return -ETIME;
201 }
202 
203 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
204 					const u8 * wdata, unsigned wdata_len,
205 					u8 * rdata, unsigned rdata_len,
206 					int force_poll)
207 {
208 	int result = 0;
209 	set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
210 	acpi_ec_write_cmd(ec, command);
211 
212 	for (; wdata_len > 0; --wdata_len) {
213 		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
214 		if (result) {
215 			printk(KERN_ERR PREFIX
216 			       "write_cmd timeout, command = %d\n", command);
217 			goto end;
218 		}
219 		set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
220 		acpi_ec_write_data(ec, *(wdata++));
221 	}
222 
223 	if (!rdata_len) {
224 		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
225 		if (result) {
226 			printk(KERN_ERR PREFIX
227 			       "finish-write timeout, command = %d\n", command);
228 			goto end;
229 		}
230 	} else if (command == ACPI_EC_COMMAND_QUERY)
231 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
232 
233 	for (; rdata_len > 0; --rdata_len) {
234 		if (test_bit(EC_FLAGS_ONLY_IBF_GPE, &ec->flags))
235 			force_poll = 1;
236 		result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, force_poll);
237 		if (result) {
238 			printk(KERN_ERR PREFIX "read timeout, command = %d\n",
239 			       command);
240 			goto end;
241 		}
242 		/* Don't expect GPE after last read */
243 		if (rdata_len > 1)
244 			set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
245 		*(rdata++) = acpi_ec_read_data(ec);
246 	}
247       end:
248 	return result;
249 }
250 
251 static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
252 			       const u8 * wdata, unsigned wdata_len,
253 			       u8 * rdata, unsigned rdata_len,
254 			       int force_poll)
255 {
256 	int status;
257 	u32 glk;
258 
259 	if (!ec || (wdata_len && !wdata) || (rdata_len && !rdata))
260 		return -EINVAL;
261 
262 	if (rdata)
263 		memset(rdata, 0, rdata_len);
264 
265 	mutex_lock(&ec->lock);
266 	if (ec->global_lock) {
267 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
268 		if (ACPI_FAILURE(status)) {
269 			mutex_unlock(&ec->lock);
270 			return -ENODEV;
271 		}
272 	}
273 
274 	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0);
275 	if (status) {
276 		printk(KERN_ERR PREFIX
277 		       "input buffer is not empty, aborting transaction\n");
278 		goto end;
279 	}
280 
281 	status = acpi_ec_transaction_unlocked(ec, command,
282 					      wdata, wdata_len,
283 					      rdata, rdata_len,
284 					      force_poll);
285 
286       end:
287 
288 	if (ec->global_lock)
289 		acpi_release_global_lock(glk);
290 	mutex_unlock(&ec->lock);
291 
292 	return status;
293 }
294 
295 /*
296  * Note: samsung nv5000 doesn't work with ec burst mode.
297  * http://bugzilla.kernel.org/show_bug.cgi?id=4980
298  */
299 int acpi_ec_burst_enable(struct acpi_ec *ec)
300 {
301 	u8 d;
302 	return acpi_ec_transaction(ec, ACPI_EC_BURST_ENABLE, NULL, 0, &d, 1, 0);
303 }
304 
305 int acpi_ec_burst_disable(struct acpi_ec *ec)
306 {
307 	return acpi_ec_transaction(ec, ACPI_EC_BURST_DISABLE, NULL, 0, NULL, 0, 0);
308 }
309 
310 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
311 {
312 	int result;
313 	u8 d;
314 
315 	result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_READ,
316 				     &address, 1, &d, 1, 0);
317 	*data = d;
318 	return result;
319 }
320 
321 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
322 {
323 	u8 wdata[2] = { address, data };
324 	return acpi_ec_transaction(ec, ACPI_EC_COMMAND_WRITE,
325 				   wdata, 2, NULL, 0, 0);
326 }
327 
328 /*
329  * Externally callable EC access functions. For now, assume 1 EC only
330  */
331 int ec_burst_enable(void)
332 {
333 	if (!first_ec)
334 		return -ENODEV;
335 	return acpi_ec_burst_enable(first_ec);
336 }
337 
338 EXPORT_SYMBOL(ec_burst_enable);
339 
340 int ec_burst_disable(void)
341 {
342 	if (!first_ec)
343 		return -ENODEV;
344 	return acpi_ec_burst_disable(first_ec);
345 }
346 
347 EXPORT_SYMBOL(ec_burst_disable);
348 
349 int ec_read(u8 addr, u8 * val)
350 {
351 	int err;
352 	u8 temp_data;
353 
354 	if (!first_ec)
355 		return -ENODEV;
356 
357 	err = acpi_ec_read(first_ec, addr, &temp_data);
358 
359 	if (!err) {
360 		*val = temp_data;
361 		return 0;
362 	} else
363 		return err;
364 }
365 
366 EXPORT_SYMBOL(ec_read);
367 
368 int ec_write(u8 addr, u8 val)
369 {
370 	int err;
371 
372 	if (!first_ec)
373 		return -ENODEV;
374 
375 	err = acpi_ec_write(first_ec, addr, val);
376 
377 	return err;
378 }
379 
380 EXPORT_SYMBOL(ec_write);
381 
382 int ec_transaction(u8 command,
383 		   const u8 * wdata, unsigned wdata_len,
384 		   u8 * rdata, unsigned rdata_len,
385 		   int force_poll)
386 {
387 	if (!first_ec)
388 		return -ENODEV;
389 
390 	return acpi_ec_transaction(first_ec, command, wdata,
391 				   wdata_len, rdata, rdata_len,
392 				   force_poll);
393 }
394 
395 EXPORT_SYMBOL(ec_transaction);
396 
397 static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
398 {
399 	int result;
400 	u8 d;
401 
402 	if (!ec || !data)
403 		return -EINVAL;
404 
405 	/*
406 	 * Query the EC to find out which _Qxx method we need to evaluate.
407 	 * Note that successful completion of the query causes the ACPI_EC_SCI
408 	 * bit to be cleared (and thus clearing the interrupt source).
409 	 */
410 
411 	result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_QUERY, NULL, 0, &d, 1, 0);
412 	if (result)
413 		return result;
414 
415 	if (!d)
416 		return -ENODATA;
417 
418 	*data = d;
419 	return 0;
420 }
421 
422 /* --------------------------------------------------------------------------
423                                 Event Management
424    -------------------------------------------------------------------------- */
425 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
426 			      acpi_handle handle, acpi_ec_query_func func,
427 			      void *data)
428 {
429 	struct acpi_ec_query_handler *handler =
430 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
431 	if (!handler)
432 		return -ENOMEM;
433 
434 	handler->query_bit = query_bit;
435 	handler->handle = handle;
436 	handler->func = func;
437 	handler->data = data;
438 	mutex_lock(&ec->lock);
439 	list_add(&handler->node, &ec->list);
440 	mutex_unlock(&ec->lock);
441 	return 0;
442 }
443 
444 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
445 
446 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
447 {
448 	struct acpi_ec_query_handler *handler, *tmp;
449 	mutex_lock(&ec->lock);
450 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
451 		if (query_bit == handler->query_bit) {
452 			list_del(&handler->node);
453 			kfree(handler);
454 		}
455 	}
456 	mutex_unlock(&ec->lock);
457 }
458 
459 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
460 
461 static void acpi_ec_gpe_query(void *ec_cxt)
462 {
463 	struct acpi_ec *ec = ec_cxt;
464 	u8 value = 0;
465 	struct acpi_ec_query_handler *handler, copy;
466 
467 	if (!ec || acpi_ec_query(ec, &value))
468 		return;
469 	mutex_lock(&ec->lock);
470 	list_for_each_entry(handler, &ec->list, node) {
471 		if (value == handler->query_bit) {
472 			/* have custom handler for this bit */
473 			memcpy(&copy, handler, sizeof(copy));
474 			mutex_unlock(&ec->lock);
475 			if (copy.func) {
476 				copy.func(copy.data);
477 			} else if (copy.handle) {
478 				acpi_evaluate_object(copy.handle, NULL, NULL, NULL);
479 			}
480 			return;
481 		}
482 	}
483 	mutex_unlock(&ec->lock);
484 }
485 
486 static u32 acpi_ec_gpe_handler(void *data)
487 {
488 	acpi_status status = AE_OK;
489 	struct acpi_ec *ec = data;
490 
491 	clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
492 	if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))
493 		wake_up(&ec->wait);
494 
495 	if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_SCI) {
496 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
497 			status = acpi_os_execute(OSL_EC_BURST_HANDLER,
498 				acpi_ec_gpe_query, ec);
499 	} else if (unlikely(!test_bit(EC_FLAGS_GPE_MODE, &ec->flags))) {
500 		/* this is non-query, must be confirmation */
501 		printk(KERN_INFO PREFIX "non-query interrupt received,"
502 			" switching to interrupt mode\n");
503 		set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
504 	}
505 
506 	return ACPI_SUCCESS(status) ?
507 	    ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
508 }
509 
510 /* --------------------------------------------------------------------------
511                              Address Space Management
512    -------------------------------------------------------------------------- */
513 
514 static acpi_status
515 acpi_ec_space_setup(acpi_handle region_handle,
516 		    u32 function, void *handler_context, void **return_context)
517 {
518 	/*
519 	 * The EC object is in the handler context and is needed
520 	 * when calling the acpi_ec_space_handler.
521 	 */
522 	*return_context = (function != ACPI_REGION_DEACTIVATE) ?
523 	    handler_context : NULL;
524 
525 	return AE_OK;
526 }
527 
528 static acpi_status
529 acpi_ec_space_handler(u32 function, acpi_physical_address address,
530 		      u32 bits, acpi_integer *value,
531 		      void *handler_context, void *region_context)
532 {
533 	struct acpi_ec *ec = handler_context;
534 	int result = 0, i = 0;
535 	u8 temp = 0;
536 
537 	if ((address > 0xFF) || !value || !handler_context)
538 		return AE_BAD_PARAMETER;
539 
540 	if (function != ACPI_READ && function != ACPI_WRITE)
541 		return AE_BAD_PARAMETER;
542 
543 	if (bits != 8 && acpi_strict)
544 		return AE_BAD_PARAMETER;
545 
546 	while (bits - i > 0) {
547 		if (function == ACPI_READ) {
548 			result = acpi_ec_read(ec, address, &temp);
549 			(*value) |= ((acpi_integer)temp) << i;
550 		} else {
551 			temp = 0xff & ((*value) >> i);
552 			result = acpi_ec_write(ec, address, temp);
553 		}
554 		i += 8;
555 		++address;
556 	}
557 
558 	switch (result) {
559 	case -EINVAL:
560 		return AE_BAD_PARAMETER;
561 		break;
562 	case -ENODEV:
563 		return AE_NOT_FOUND;
564 		break;
565 	case -ETIME:
566 		return AE_TIME;
567 		break;
568 	default:
569 		return AE_OK;
570 	}
571 }
572 
573 /* --------------------------------------------------------------------------
574                               FS Interface (/proc)
575    -------------------------------------------------------------------------- */
576 
577 static struct proc_dir_entry *acpi_ec_dir;
578 
579 static int acpi_ec_read_info(struct seq_file *seq, void *offset)
580 {
581 	struct acpi_ec *ec = seq->private;
582 
583 	if (!ec)
584 		goto end;
585 
586 	seq_printf(seq, "gpe:\t\t\t0x%02x\n", (u32) ec->gpe);
587 	seq_printf(seq, "ports:\t\t\t0x%02x, 0x%02x\n",
588 		   (unsigned)ec->command_addr, (unsigned)ec->data_addr);
589 	seq_printf(seq, "use global lock:\t%s\n",
590 		   ec->global_lock ? "yes" : "no");
591       end:
592 	return 0;
593 }
594 
595 static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
596 {
597 	return single_open(file, acpi_ec_read_info, PDE(inode)->data);
598 }
599 
600 static struct file_operations acpi_ec_info_ops = {
601 	.open = acpi_ec_info_open_fs,
602 	.read = seq_read,
603 	.llseek = seq_lseek,
604 	.release = single_release,
605 	.owner = THIS_MODULE,
606 };
607 
608 static int acpi_ec_add_fs(struct acpi_device *device)
609 {
610 	struct proc_dir_entry *entry = NULL;
611 
612 	if (!acpi_device_dir(device)) {
613 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
614 						     acpi_ec_dir);
615 		if (!acpi_device_dir(device))
616 			return -ENODEV;
617 	}
618 
619 	entry = create_proc_entry(ACPI_EC_FILE_INFO, S_IRUGO,
620 				  acpi_device_dir(device));
621 	if (!entry)
622 		return -ENODEV;
623 	else {
624 		entry->proc_fops = &acpi_ec_info_ops;
625 		entry->data = acpi_driver_data(device);
626 		entry->owner = THIS_MODULE;
627 	}
628 
629 	return 0;
630 }
631 
632 static int acpi_ec_remove_fs(struct acpi_device *device)
633 {
634 
635 	if (acpi_device_dir(device)) {
636 		remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
637 		remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
638 		acpi_device_dir(device) = NULL;
639 	}
640 
641 	return 0;
642 }
643 
644 /* --------------------------------------------------------------------------
645                                Driver Interface
646    -------------------------------------------------------------------------- */
647 static acpi_status
648 ec_parse_io_ports(struct acpi_resource *resource, void *context);
649 
650 static struct acpi_ec *make_acpi_ec(void)
651 {
652 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
653 	if (!ec)
654 		return NULL;
655 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
656 	mutex_init(&ec->lock);
657 	init_waitqueue_head(&ec->wait);
658 	INIT_LIST_HEAD(&ec->list);
659 	return ec;
660 }
661 
662 static acpi_status
663 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
664 			       void *context, void **return_value)
665 {
666 	struct acpi_namespace_node *node = handle;
667 	struct acpi_ec *ec = context;
668 	int value = 0;
669 	if (sscanf(node->name.ascii, "_Q%x", &value) == 1) {
670 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
671 	}
672 	return AE_OK;
673 }
674 
675 static acpi_status
676 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
677 {
678 	acpi_status status;
679 
680 	struct acpi_ec *ec = context;
681 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
682 				     ec_parse_io_ports, ec);
683 	if (ACPI_FAILURE(status))
684 		return status;
685 
686 	/* Get GPE bit assignment (EC events). */
687 	/* TODO: Add support for _GPE returning a package */
688 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec->gpe);
689 	if (ACPI_FAILURE(status))
690 		return status;
691 	/* Find and register all query methods */
692 	acpi_walk_namespace(ACPI_TYPE_METHOD, handle, 1,
693 			    acpi_ec_register_query_methods, ec, NULL);
694 	/* Use the global lock for all EC transactions? */
695 	acpi_evaluate_integer(handle, "_GLK", NULL, &ec->global_lock);
696 	ec->handle = handle;
697 	return AE_CTRL_TERMINATE;
698 }
699 
700 static void ec_remove_handlers(struct acpi_ec *ec)
701 {
702 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
703 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
704 		printk(KERN_ERR PREFIX "failed to remove space handler\n");
705 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
706 				&acpi_ec_gpe_handler)))
707 		printk(KERN_ERR PREFIX "failed to remove gpe handler\n");
708 	ec->handlers_installed = 0;
709 }
710 
711 static int acpi_ec_add(struct acpi_device *device)
712 {
713 	struct acpi_ec *ec = NULL;
714 
715 	if (!device)
716 		return -EINVAL;
717 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
718 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
719 
720 	/* Check for boot EC */
721 	if (boot_ec) {
722 		if (boot_ec->handle == device->handle) {
723 			/* Pre-loaded EC from DSDT, just move pointer */
724 			ec = boot_ec;
725 			boot_ec = NULL;
726 			goto end;
727 		} else if (boot_ec->handle == ACPI_ROOT_OBJECT) {
728 			/* ECDT-based EC, time to shut it down */
729 			ec_remove_handlers(boot_ec);
730 			kfree(boot_ec);
731 			first_ec = boot_ec = NULL;
732 		}
733 	}
734 
735 	ec = make_acpi_ec();
736 	if (!ec)
737 		return -ENOMEM;
738 
739 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
740 	    AE_CTRL_TERMINATE) {
741 		kfree(ec);
742 		return -EINVAL;
743 	}
744 	ec->handle = device->handle;
745       end:
746 	if (!first_ec)
747 		first_ec = ec;
748 	acpi_driver_data(device) = ec;
749 	acpi_ec_add_fs(device);
750 	printk(KERN_INFO PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
751 			  ec->gpe, ec->command_addr, ec->data_addr);
752 	printk(KERN_INFO PREFIX "driver started in %s mode\n",
753 		(test_bit(EC_FLAGS_GPE_MODE, &ec->flags))?"interrupt":"poll");
754 	return 0;
755 }
756 
757 static int acpi_ec_remove(struct acpi_device *device, int type)
758 {
759 	struct acpi_ec *ec;
760 	struct acpi_ec_query_handler *handler, *tmp;
761 
762 	if (!device)
763 		return -EINVAL;
764 
765 	ec = acpi_driver_data(device);
766 	mutex_lock(&ec->lock);
767 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
768 		list_del(&handler->node);
769 		kfree(handler);
770 	}
771 	mutex_unlock(&ec->lock);
772 	acpi_ec_remove_fs(device);
773 	acpi_driver_data(device) = NULL;
774 	if (ec == first_ec)
775 		first_ec = NULL;
776 	kfree(ec);
777 	return 0;
778 }
779 
780 static acpi_status
781 ec_parse_io_ports(struct acpi_resource *resource, void *context)
782 {
783 	struct acpi_ec *ec = context;
784 
785 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
786 		return AE_OK;
787 
788 	/*
789 	 * The first address region returned is the data port, and
790 	 * the second address region returned is the status/command
791 	 * port.
792 	 */
793 	if (ec->data_addr == 0)
794 		ec->data_addr = resource->data.io.minimum;
795 	else if (ec->command_addr == 0)
796 		ec->command_addr = resource->data.io.minimum;
797 	else
798 		return AE_CTRL_TERMINATE;
799 
800 	return AE_OK;
801 }
802 
803 static int ec_install_handlers(struct acpi_ec *ec)
804 {
805 	acpi_status status;
806 	if (ec->handlers_installed)
807 		return 0;
808 	status = acpi_install_gpe_handler(NULL, ec->gpe,
809 					  ACPI_GPE_EDGE_TRIGGERED,
810 					  &acpi_ec_gpe_handler, ec);
811 	if (ACPI_FAILURE(status))
812 		return -ENODEV;
813 
814 	acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
815 	acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
816 
817 	status = acpi_install_address_space_handler(ec->handle,
818 						    ACPI_ADR_SPACE_EC,
819 						    &acpi_ec_space_handler,
820 						    &acpi_ec_space_setup, ec);
821 	if (ACPI_FAILURE(status)) {
822 		acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler);
823 		return -ENODEV;
824 	}
825 
826 	ec->handlers_installed = 1;
827 	return 0;
828 }
829 
830 static int acpi_ec_start(struct acpi_device *device)
831 {
832 	struct acpi_ec *ec;
833 	int ret = 0;
834 
835 	if (!device)
836 		return -EINVAL;
837 
838 	ec = acpi_driver_data(device);
839 
840 	if (!ec)
841 		return -EINVAL;
842 
843 	ret = ec_install_handlers(ec);
844 
845 	/* EC is fully operational, allow queries */
846 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
847 	return ret;
848 }
849 
850 static int acpi_ec_stop(struct acpi_device *device, int type)
851 {
852 	struct acpi_ec *ec;
853 	if (!device)
854 		return -EINVAL;
855 	ec = acpi_driver_data(device);
856 	if (!ec)
857 		return -EINVAL;
858 	ec_remove_handlers(ec);
859 
860 	return 0;
861 }
862 
863 int __init acpi_ec_ecdt_probe(void)
864 {
865 	int ret;
866 	acpi_status status;
867 	struct acpi_table_ecdt *ecdt_ptr;
868 
869 	boot_ec = make_acpi_ec();
870 	if (!boot_ec)
871 		return -ENOMEM;
872 	/*
873 	 * Generate a boot ec context
874 	 */
875 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
876 				(struct acpi_table_header **)&ecdt_ptr);
877 	if (ACPI_SUCCESS(status)) {
878 		printk(KERN_INFO PREFIX "EC description table is found, configuring boot EC\n");
879 		boot_ec->command_addr = ecdt_ptr->control.address;
880 		boot_ec->data_addr = ecdt_ptr->data.address;
881 		boot_ec->gpe = ecdt_ptr->gpe;
882 		boot_ec->handle = ACPI_ROOT_OBJECT;
883 	} else {
884 		printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
885 		status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
886 						boot_ec, NULL);
887 		/* Check that acpi_get_devices actually find something */
888 		if (ACPI_FAILURE(status) || !boot_ec->handle)
889 			goto error;
890 	}
891 
892 	ret = ec_install_handlers(boot_ec);
893 	if (!ret) {
894 		first_ec = boot_ec;
895 		return 0;
896 	}
897       error:
898 	kfree(boot_ec);
899 	boot_ec = NULL;
900 	return -ENODEV;
901 }
902 
903 static int __init acpi_ec_init(void)
904 {
905 	int result = 0;
906 
907 	if (acpi_disabled)
908 		return 0;
909 
910 	acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
911 	if (!acpi_ec_dir)
912 		return -ENODEV;
913 
914 	/* Now register the driver for the EC */
915 	result = acpi_bus_register_driver(&acpi_ec_driver);
916 	if (result < 0) {
917 		remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
918 		return -ENODEV;
919 	}
920 
921 	return result;
922 }
923 
924 subsys_initcall(acpi_ec_init);
925 
926 /* EC driver currently not unloadable */
927 #if 0
928 static void __exit acpi_ec_exit(void)
929 {
930 
931 	acpi_bus_unregister_driver(&acpi_ec_driver);
932 
933 	remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
934 
935 	return;
936 }
937 #endif	/* 0 */
938