xref: /linux/drivers/acpi/ec.c (revision b454cc6636d254fbf6049b73e9560aee76fb04a3)
1 /*
2  *  acpi_ec.c - ACPI Embedded Controller Driver ($Revision: 38 $)
3  *
4  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7  *
8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or (at
13  *  your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful, but
16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  *  General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License along
21  *  with this program; if not, write to the Free Software Foundation, Inc.,
22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23  *
24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25  */
26 
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/init.h>
30 #include <linux/types.h>
31 #include <linux/delay.h>
32 #include <linux/proc_fs.h>
33 #include <linux/seq_file.h>
34 #include <linux/interrupt.h>
35 #include <asm/io.h>
36 #include <acpi/acpi_bus.h>
37 #include <acpi/acpi_drivers.h>
38 #include <acpi/actypes.h>
39 
40 #define _COMPONENT		ACPI_EC_COMPONENT
41 ACPI_MODULE_NAME("acpi_ec")
42 #define ACPI_EC_COMPONENT		0x00100000
43 #define ACPI_EC_CLASS			"embedded_controller"
44 #define ACPI_EC_HID			"PNP0C09"
45 #define ACPI_EC_DRIVER_NAME		"ACPI Embedded Controller Driver"
46 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
47 #define ACPI_EC_FILE_INFO		"info"
48 #undef PREFIX
49 #define PREFIX				"ACPI: EC: "
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 /* EC commands */
56 enum ec_command {
57 	ACPI_EC_COMMAND_READ = 0x80,
58 	ACPI_EC_COMMAND_WRITE = 0x81,
59 	ACPI_EC_BURST_ENABLE = 0x82,
60 	ACPI_EC_BURST_DISABLE = 0x83,
61 	ACPI_EC_COMMAND_QUERY = 0x84,
62 };
63 /* EC events */
64 enum ec_event {
65 	ACPI_EC_EVENT_OBF_1 = 1,	/* Output buffer full */
66 	ACPI_EC_EVENT_IBF_0,	/* Input buffer empty */
67 };
68 
69 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
70 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
71 
72 static enum ec_mode {
73 	EC_INTR = 1,		/* Output buffer full */
74 	EC_POLL,		/* Input buffer empty */
75 } acpi_ec_mode = EC_INTR;
76 
77 static int acpi_ec_remove(struct acpi_device *device, int type);
78 static int acpi_ec_start(struct acpi_device *device);
79 static int acpi_ec_stop(struct acpi_device *device, int type);
80 static int acpi_ec_add(struct acpi_device *device);
81 
82 static struct acpi_driver acpi_ec_driver = {
83 	.name = ACPI_EC_DRIVER_NAME,
84 	.class = ACPI_EC_CLASS,
85 	.ids = ACPI_EC_HID,
86 	.ops = {
87 		.add = acpi_ec_add,
88 		.remove = acpi_ec_remove,
89 		.start = acpi_ec_start,
90 		.stop = acpi_ec_stop,
91 		},
92 };
93 
94 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
95 static struct acpi_ec {
96 	acpi_handle handle;
97 	unsigned long uid;
98 	unsigned long gpe;
99 	unsigned long command_addr;
100 	unsigned long data_addr;
101 	unsigned long global_lock;
102 	struct mutex lock;
103 	atomic_t query_pending;
104 	atomic_t leaving_burst;	/* 0 : No, 1 : Yes, 2: abort */
105 	wait_queue_head_t wait;
106 } *ec_ecdt;
107 
108 /* External interfaces use first EC only, so remember */
109 static struct acpi_device *first_ec;
110 
111 /* --------------------------------------------------------------------------
112                              Transaction Management
113    -------------------------------------------------------------------------- */
114 
115 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
116 {
117 	return inb(ec->command_addr);
118 }
119 
120 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
121 {
122 	return inb(ec->data_addr);
123 }
124 
125 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
126 {
127 	outb(command, ec->command_addr);
128 }
129 
130 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
131 {
132 	outb(data, ec->data_addr);
133 }
134 
135 static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)
136 {
137 	u8 status = acpi_ec_read_status(ec);
138 
139 	if (event == ACPI_EC_EVENT_OBF_1) {
140 		if (status & ACPI_EC_FLAG_OBF)
141 			return 1;
142 	} else if (event == ACPI_EC_EVENT_IBF_0) {
143 		if (!(status & ACPI_EC_FLAG_IBF))
144 			return 1;
145 	}
146 
147 	return 0;
148 }
149 
150 static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event)
151 {
152 	if (acpi_ec_mode == EC_POLL) {
153 		unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
154 		while (time_before(jiffies, delay)) {
155 			if (acpi_ec_check_status(ec, event))
156 				return 0;
157 		}
158 	} else {
159 		if (wait_event_timeout(ec->wait,
160 				       acpi_ec_check_status(ec, event),
161 				       msecs_to_jiffies(ACPI_EC_DELAY)) ||
162 		    acpi_ec_check_status(ec, event)) {
163 			return 0;
164 		} else {
165 			printk(KERN_ERR PREFIX "acpi_ec_wait timeout,"
166 			       " status = %d, expect_event = %d\n",
167 			       acpi_ec_read_status(ec), event);
168 		}
169 	}
170 
171 	return -ETIME;
172 }
173 
174 #ifdef ACPI_FUTURE_USAGE
175 /*
176  * Note: samsung nv5000 doesn't work with ec burst mode.
177  * http://bugzilla.kernel.org/show_bug.cgi?id=4980
178  */
179 int acpi_ec_enter_burst_mode(struct acpi_ec *ec)
180 {
181 	u8 tmp = 0;
182 	u8 status = 0;
183 
184 	status = acpi_ec_read_status(ec);
185 	if (status != -EINVAL && !(status & ACPI_EC_FLAG_BURST)) {
186 		status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
187 		if (status)
188 			goto end;
189 		acpi_ec_write_cmd(ec, ACPI_EC_BURST_ENABLE);
190 		status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1);
191 		tmp = acpi_ec_read_data(ec);
192 		if (tmp != 0x90) {	/* Burst ACK byte */
193 			return -EINVAL;
194 		}
195 	}
196 
197 	atomic_set(&ec->leaving_burst, 0);
198 	return 0;
199       end:
200 	ACPI_EXCEPTION((AE_INFO, status, "EC wait, burst mode"));
201 	return -1;
202 }
203 
204 int acpi_ec_leave_burst_mode(struct acpi_ec *ec)
205 {
206 	u8 status = 0;
207 
208 	status = acpi_ec_read_status(ec);
209 	if (status != -EINVAL && (status & ACPI_EC_FLAG_BURST)) {
210 		status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
211 		if (status)
212 			goto end;
213 		acpi_ec_write_cmd(ec, ACPI_EC_BURST_DISABLE);
214 		acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
215 	}
216 	atomic_set(&ec->leaving_burst, 1);
217 	return 0;
218       end:
219 	ACPI_EXCEPTION((AE_INFO, status, "EC leave burst mode"));
220 	return -1;
221 }
222 #endif				/* ACPI_FUTURE_USAGE */
223 
224 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
225 					const u8 * wdata, unsigned wdata_len,
226 					u8 * rdata, unsigned rdata_len)
227 {
228 	int result = 0;
229 
230 	acpi_ec_write_cmd(ec, command);
231 
232 	for (; wdata_len > 0; --wdata_len) {
233 		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
234 		if (result) {
235 			printk(KERN_ERR PREFIX
236 			       "write_cmd timeout, command = %d\n", command);
237 			goto end;
238 		}
239 		acpi_ec_write_data(ec, *(wdata++));
240 	}
241 
242 	if (!rdata_len) {
243 		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
244 		if (result) {
245 			printk(KERN_ERR PREFIX
246 			       "finish-write timeout, command = %d\n", command);
247 			goto end;
248 		}
249 	} else if (command == ACPI_EC_COMMAND_QUERY) {
250 		atomic_set(&ec->query_pending, 0);
251 	}
252 
253 	for (; rdata_len > 0; --rdata_len) {
254 		result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1);
255 		if (result) {
256 			printk(KERN_ERR PREFIX "read timeout, command = %d\n",
257 			       command);
258 			goto end;
259 		}
260 
261 		*(rdata++) = acpi_ec_read_data(ec);
262 	}
263       end:
264 	return result;
265 }
266 
267 static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
268 			       const u8 * wdata, unsigned wdata_len,
269 			       u8 * rdata, unsigned rdata_len)
270 {
271 	int status;
272 	u32 glk;
273 
274 	if (!ec || (wdata_len && !wdata) || (rdata_len && !rdata))
275 		return -EINVAL;
276 
277 	if (rdata)
278 		memset(rdata, 0, rdata_len);
279 
280 	mutex_lock(&ec->lock);
281 	if (ec->global_lock) {
282 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
283 		if (ACPI_FAILURE(status))
284 			return -ENODEV;
285 	}
286 
287 	/* Make sure GPE is enabled before doing transaction */
288 	acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
289 
290 	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
291 	if (status) {
292 		printk(KERN_DEBUG PREFIX
293 		       "input buffer is not empty, aborting transaction\n");
294 		goto end;
295 	}
296 
297 	status = acpi_ec_transaction_unlocked(ec, command,
298 					      wdata, wdata_len,
299 					      rdata, rdata_len);
300 
301       end:
302 
303 	if (ec->global_lock)
304 		acpi_release_global_lock(glk);
305 	mutex_unlock(&ec->lock);
306 
307 	return status;
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);
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);
326 }
327 
328 /*
329  * Externally callable EC access functions. For now, assume 1 EC only
330  */
331 int ec_read(u8 addr, u8 * val)
332 {
333 	struct acpi_ec *ec;
334 	int err;
335 	u8 temp_data;
336 
337 	if (!first_ec)
338 		return -ENODEV;
339 
340 	ec = acpi_driver_data(first_ec);
341 
342 	err = acpi_ec_read(ec, addr, &temp_data);
343 
344 	if (!err) {
345 		*val = temp_data;
346 		return 0;
347 	} else
348 		return err;
349 }
350 
351 EXPORT_SYMBOL(ec_read);
352 
353 int ec_write(u8 addr, u8 val)
354 {
355 	struct acpi_ec *ec;
356 	int err;
357 
358 	if (!first_ec)
359 		return -ENODEV;
360 
361 	ec = acpi_driver_data(first_ec);
362 
363 	err = acpi_ec_write(ec, addr, val);
364 
365 	return err;
366 }
367 
368 EXPORT_SYMBOL(ec_write);
369 
370 int ec_transaction(u8 command,
371 			  const u8 * wdata, unsigned wdata_len,
372 			  u8 * rdata, unsigned rdata_len)
373 {
374 	struct acpi_ec *ec;
375 
376 	if (!first_ec)
377 		return -ENODEV;
378 
379 	ec = acpi_driver_data(first_ec);
380 
381 	return acpi_ec_transaction(ec, command, wdata,
382 				   wdata_len, rdata, rdata_len);
383 }
384 
385 EXPORT_SYMBOL(ec_transaction);
386 
387 static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
388 {
389 	int result;
390 	u8 d;
391 
392 	if (!ec || !data)
393 		return -EINVAL;
394 
395 	/*
396 	 * Query the EC to find out which _Qxx method we need to evaluate.
397 	 * Note that successful completion of the query causes the ACPI_EC_SCI
398 	 * bit to be cleared (and thus clearing the interrupt source).
399 	 */
400 
401 	result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_QUERY, NULL, 0, &d, 1);
402 	if (result)
403 		return result;
404 
405 	if (!d)
406 		return -ENODATA;
407 
408 	*data = d;
409 	return 0;
410 }
411 
412 /* --------------------------------------------------------------------------
413                                 Event Management
414    -------------------------------------------------------------------------- */
415 
416 static void acpi_ec_gpe_query(void *ec_cxt)
417 {
418 	struct acpi_ec *ec = (struct acpi_ec *)ec_cxt;
419 	u8 value = 0;
420 	char object_name[8];
421 
422 	if (!ec || acpi_ec_query(ec, &value))
423 		return;
424 
425 	snprintf(object_name, 8, "_Q%2.2X", value);
426 
427 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s", object_name));
428 
429 	acpi_evaluate_object(ec->handle, object_name, NULL, NULL);
430 }
431 
432 static u32 acpi_ec_gpe_handler(void *data)
433 {
434 	acpi_status status = AE_OK;
435 	u8 value;
436 	struct acpi_ec *ec = (struct acpi_ec *)data;
437 
438 	if (acpi_ec_mode == EC_INTR) {
439 		wake_up(&ec->wait);
440 	}
441 
442 	value = acpi_ec_read_status(ec);
443 	if ((value & ACPI_EC_FLAG_SCI) && !atomic_read(&ec->query_pending)) {
444 		atomic_set(&ec->query_pending, 1);
445 		status =
446 		    acpi_os_execute(OSL_EC_BURST_HANDLER, acpi_ec_gpe_query,
447 				    ec);
448 	}
449 
450 	return status == AE_OK ?
451 	    ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
452 }
453 
454 /* --------------------------------------------------------------------------
455                              Address Space Management
456    -------------------------------------------------------------------------- */
457 
458 static acpi_status
459 acpi_ec_space_setup(acpi_handle region_handle,
460 		    u32 function, void *handler_context, void **return_context)
461 {
462 	/*
463 	 * The EC object is in the handler context and is needed
464 	 * when calling the acpi_ec_space_handler.
465 	 */
466 	*return_context = (function != ACPI_REGION_DEACTIVATE) ?
467 	    handler_context : NULL;
468 
469 	return AE_OK;
470 }
471 
472 static acpi_status
473 acpi_ec_space_handler(u32 function,
474 		      acpi_physical_address address,
475 		      u32 bit_width,
476 		      acpi_integer * value,
477 		      void *handler_context, void *region_context)
478 {
479 	int result = 0;
480 	struct acpi_ec *ec = NULL;
481 	u64 temp = *value;
482 	acpi_integer f_v = 0;
483 	int i = 0;
484 
485 	if ((address > 0xFF) || !value || !handler_context)
486 		return AE_BAD_PARAMETER;
487 
488 	if (bit_width != 8 && acpi_strict) {
489 		return AE_BAD_PARAMETER;
490 	}
491 
492 	ec = (struct acpi_ec *)handler_context;
493 
494       next_byte:
495 	switch (function) {
496 	case ACPI_READ:
497 		temp = 0;
498 		result = acpi_ec_read(ec, (u8) address, (u8 *) & temp);
499 		break;
500 	case ACPI_WRITE:
501 		result = acpi_ec_write(ec, (u8) address, (u8) temp);
502 		break;
503 	default:
504 		result = -EINVAL;
505 		goto out;
506 		break;
507 	}
508 
509 	bit_width -= 8;
510 	if (bit_width) {
511 		if (function == ACPI_READ)
512 			f_v |= temp << 8 * i;
513 		if (function == ACPI_WRITE)
514 			temp >>= 8;
515 		i++;
516 		address++;
517 		goto next_byte;
518 	}
519 
520 	if (function == ACPI_READ) {
521 		f_v |= temp << 8 * i;
522 		*value = f_v;
523 	}
524 
525       out:
526 	switch (result) {
527 	case -EINVAL:
528 		return AE_BAD_PARAMETER;
529 		break;
530 	case -ENODEV:
531 		return AE_NOT_FOUND;
532 		break;
533 	case -ETIME:
534 		return AE_TIME;
535 		break;
536 	default:
537 		return AE_OK;
538 	}
539 }
540 
541 /* --------------------------------------------------------------------------
542                               FS Interface (/proc)
543    -------------------------------------------------------------------------- */
544 
545 static struct proc_dir_entry *acpi_ec_dir;
546 
547 static int acpi_ec_read_info(struct seq_file *seq, void *offset)
548 {
549 	struct acpi_ec *ec = (struct acpi_ec *)seq->private;
550 
551 	if (!ec)
552 		goto end;
553 
554 	seq_printf(seq, "gpe:                 0x%02x\n", (u32) ec->gpe);
555 	seq_printf(seq, "ports:                   0x%02x, 0x%02x\n",
556 		   (u32) ec->command_addr, (u32) ec->data_addr);
557 	seq_printf(seq, "use global lock:         %s\n",
558 		   ec->global_lock ? "yes" : "no");
559 	acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
560 
561       end:
562 	return 0;
563 }
564 
565 static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
566 {
567 	return single_open(file, acpi_ec_read_info, PDE(inode)->data);
568 }
569 
570 static struct file_operations acpi_ec_info_ops = {
571 	.open = acpi_ec_info_open_fs,
572 	.read = seq_read,
573 	.llseek = seq_lseek,
574 	.release = single_release,
575 	.owner = THIS_MODULE,
576 };
577 
578 static int acpi_ec_add_fs(struct acpi_device *device)
579 {
580 	struct proc_dir_entry *entry = NULL;
581 
582 	if (!acpi_device_dir(device)) {
583 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
584 						     acpi_ec_dir);
585 		if (!acpi_device_dir(device))
586 			return -ENODEV;
587 	}
588 
589 	entry = create_proc_entry(ACPI_EC_FILE_INFO, S_IRUGO,
590 				  acpi_device_dir(device));
591 	if (!entry)
592 		return -ENODEV;
593 	else {
594 		entry->proc_fops = &acpi_ec_info_ops;
595 		entry->data = acpi_driver_data(device);
596 		entry->owner = THIS_MODULE;
597 	}
598 
599 	return 0;
600 }
601 
602 static int acpi_ec_remove_fs(struct acpi_device *device)
603 {
604 
605 	if (acpi_device_dir(device)) {
606 		remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
607 		remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
608 		acpi_device_dir(device) = NULL;
609 	}
610 
611 	return 0;
612 }
613 
614 /* --------------------------------------------------------------------------
615                                Driver Interface
616    -------------------------------------------------------------------------- */
617 
618 static int acpi_ec_add(struct acpi_device *device)
619 {
620 	int result = 0;
621 	acpi_status status = AE_OK;
622 	struct acpi_ec *ec = NULL;
623 
624 	if (!device)
625 		return -EINVAL;
626 
627 	ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
628 	if (!ec)
629 		return -ENOMEM;
630 
631 	ec->handle = device->handle;
632 	ec->uid = -1;
633 	mutex_init(&ec->lock);
634 	atomic_set(&ec->query_pending, 0);
635 	if (acpi_ec_mode == EC_INTR) {
636 		atomic_set(&ec->leaving_burst, 1);
637 		init_waitqueue_head(&ec->wait);
638 	}
639 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
640 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
641 	acpi_driver_data(device) = ec;
642 
643 	/* Use the global lock for all EC transactions? */
644 	acpi_evaluate_integer(ec->handle, "_GLK", NULL, &ec->global_lock);
645 
646 	/* XXX we don't test uids, because on some boxes ecdt uid = 0, see:
647 	   http://bugzilla.kernel.org/show_bug.cgi?id=6111 */
648 	if (ec_ecdt) {
649 		acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
650 						  ACPI_ADR_SPACE_EC,
651 						  &acpi_ec_space_handler);
652 
653 		acpi_remove_gpe_handler(NULL, ec_ecdt->gpe,
654 					&acpi_ec_gpe_handler);
655 
656 		kfree(ec_ecdt);
657 	}
658 
659 	/* Get GPE bit assignment (EC events). */
660 	/* TODO: Add support for _GPE returning a package */
661 	status = acpi_evaluate_integer(ec->handle, "_GPE", NULL, &ec->gpe);
662 	if (ACPI_FAILURE(status)) {
663 		ACPI_EXCEPTION((AE_INFO, status,
664 				"Obtaining GPE bit assignment"));
665 		result = -ENODEV;
666 		goto end;
667 	}
668 
669 	result = acpi_ec_add_fs(device);
670 	if (result)
671 		goto end;
672 
673 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s [%s] (gpe %d) interrupt mode.",
674 			  acpi_device_name(device), acpi_device_bid(device),
675 			  (u32) ec->gpe));
676 
677 	if (!first_ec)
678 		first_ec = device;
679 
680       end:
681 	if (result)
682 		kfree(ec);
683 
684 	return result;
685 }
686 
687 static int acpi_ec_remove(struct acpi_device *device, int type)
688 {
689 	struct acpi_ec *ec = NULL;
690 
691 	if (!device)
692 		return -EINVAL;
693 
694 	ec = acpi_driver_data(device);
695 
696 	acpi_ec_remove_fs(device);
697 
698 	kfree(ec);
699 
700 	return 0;
701 }
702 
703 static acpi_status
704 acpi_ec_io_ports(struct acpi_resource *resource, void *context)
705 {
706 	struct acpi_ec *ec = (struct acpi_ec *)context;
707 
708 	if (resource->type != ACPI_RESOURCE_TYPE_IO) {
709 		return AE_OK;
710 	}
711 
712 	/*
713 	 * The first address region returned is the data port, and
714 	 * the second address region returned is the status/command
715 	 * port.
716 	 */
717 	if (ec->data_addr == 0) {
718 		ec->data_addr = resource->data.io.minimum;
719 	} else if (ec->command_addr == 0) {
720 		ec->command_addr = resource->data.io.minimum;
721 	} else {
722 		return AE_CTRL_TERMINATE;
723 	}
724 
725 	return AE_OK;
726 }
727 
728 static int acpi_ec_start(struct acpi_device *device)
729 {
730 	acpi_status status = AE_OK;
731 	struct acpi_ec *ec = NULL;
732 
733 	if (!device)
734 		return -EINVAL;
735 
736 	ec = acpi_driver_data(device);
737 
738 	if (!ec)
739 		return -EINVAL;
740 
741 	/*
742 	 * Get I/O port addresses. Convert to GAS format.
743 	 */
744 	status = acpi_walk_resources(ec->handle, METHOD_NAME__CRS,
745 				     acpi_ec_io_ports, ec);
746 	if (ACPI_FAILURE(status) || ec->command_addr == 0) {
747 		ACPI_EXCEPTION((AE_INFO, status,
748 				"Error getting I/O port addresses"));
749 		return -ENODEV;
750 	}
751 
752 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "gpe=0x%02lx, ports=0x%2lx,0x%2lx",
753 			  ec->gpe, ec->command_addr, ec->data_addr));
754 
755 	/*
756 	 * Install GPE handler
757 	 */
758 	status = acpi_install_gpe_handler(NULL, ec->gpe,
759 					  ACPI_GPE_EDGE_TRIGGERED,
760 					  &acpi_ec_gpe_handler, ec);
761 	if (ACPI_FAILURE(status)) {
762 		return -ENODEV;
763 	}
764 	acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
765 	acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
766 
767 	status = acpi_install_address_space_handler(ec->handle,
768 						    ACPI_ADR_SPACE_EC,
769 						    &acpi_ec_space_handler,
770 						    &acpi_ec_space_setup, ec);
771 	if (ACPI_FAILURE(status)) {
772 		acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler);
773 		return -ENODEV;
774 	}
775 
776 	return AE_OK;
777 }
778 
779 static int acpi_ec_stop(struct acpi_device *device, int type)
780 {
781 	acpi_status status = AE_OK;
782 	struct acpi_ec *ec = NULL;
783 
784 	if (!device)
785 		return -EINVAL;
786 
787 	ec = acpi_driver_data(device);
788 
789 	status = acpi_remove_address_space_handler(ec->handle,
790 						   ACPI_ADR_SPACE_EC,
791 						   &acpi_ec_space_handler);
792 	if (ACPI_FAILURE(status))
793 		return -ENODEV;
794 
795 	status = acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler);
796 	if (ACPI_FAILURE(status))
797 		return -ENODEV;
798 
799 	return 0;
800 }
801 
802 static acpi_status __init
803 acpi_fake_ecdt_callback(acpi_handle handle,
804 			u32 Level, void *context, void **retval)
805 {
806 	acpi_status status;
807 
808 	mutex_init(&ec_ecdt->lock);
809 	if (acpi_ec_mode == EC_INTR) {
810 		init_waitqueue_head(&ec_ecdt->wait);
811 	}
812 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
813 				     acpi_ec_io_ports, ec_ecdt);
814 	if (ACPI_FAILURE(status))
815 		return status;
816 
817 	ec_ecdt->uid = -1;
818 	acpi_evaluate_integer(handle, "_UID", NULL, &ec_ecdt->uid);
819 
820 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->gpe);
821 	if (ACPI_FAILURE(status))
822 		return status;
823 	ec_ecdt->global_lock = TRUE;
824 	ec_ecdt->handle = handle;
825 
826 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "GPE=0x%02lx, ports=0x%2lx, 0x%2lx",
827 			  ec_ecdt->gpe, ec_ecdt->command_addr,
828 			  ec_ecdt->data_addr));
829 
830 	return AE_CTRL_TERMINATE;
831 }
832 
833 /*
834  * Some BIOS (such as some from Gateway laptops) access EC region very early
835  * such as in BAT0._INI or EC._INI before an EC device is found and
836  * do not provide an ECDT. According to ACPI spec, ECDT isn't mandatorily
837  * required, but if EC regison is accessed early, it is required.
838  * The routine tries to workaround the BIOS bug by pre-scan EC device
839  * It assumes that _CRS, _HID, _GPE, _UID methods of EC don't touch any
840  * op region (since _REG isn't invoked yet). The assumption is true for
841  * all systems found.
842  */
843 static int __init acpi_ec_fake_ecdt(void)
844 {
845 	acpi_status status;
846 	int ret = 0;
847 
848 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Try to make an fake ECDT"));
849 
850 	ec_ecdt = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
851 	if (!ec_ecdt) {
852 		ret = -ENOMEM;
853 		goto error;
854 	}
855 
856 	status = acpi_get_devices(ACPI_EC_HID,
857 				  acpi_fake_ecdt_callback, NULL, NULL);
858 	if (ACPI_FAILURE(status)) {
859 		kfree(ec_ecdt);
860 		ec_ecdt = NULL;
861 		ret = -ENODEV;
862 		ACPI_EXCEPTION((AE_INFO, status, "Can't make an fake ECDT"));
863 		goto error;
864 	}
865 	return 0;
866       error:
867 	return ret;
868 }
869 
870 static int __init acpi_ec_get_real_ecdt(void)
871 {
872 	acpi_status status;
873 	struct acpi_table_ecdt *ecdt_ptr;
874 
875 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
876 				(struct acpi_table_header **)&ecdt_ptr);
877 	if (ACPI_FAILURE(status))
878 		return -ENODEV;
879 
880 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found ECDT"));
881 
882 	/*
883 	 * Generate a temporary ec context to use until the namespace is scanned
884 	 */
885 	ec_ecdt = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
886 	if (!ec_ecdt)
887 		return -ENOMEM;
888 
889 	mutex_init(&ec_ecdt->lock);
890 	if (acpi_ec_mode == EC_INTR) {
891 		init_waitqueue_head(&ec_ecdt->wait);
892 	}
893 	ec_ecdt->command_addr = ecdt_ptr->control.address;
894 	ec_ecdt->data_addr = ecdt_ptr->data.address;
895 	ec_ecdt->gpe = ecdt_ptr->gpe;
896 	/* use the GL just to be safe */
897 	ec_ecdt->global_lock = TRUE;
898 	ec_ecdt->uid = ecdt_ptr->uid;
899 
900 	status = acpi_get_handle(NULL, ecdt_ptr->id, &ec_ecdt->handle);
901 	if (ACPI_FAILURE(status)) {
902 		goto error;
903 	}
904 
905 	return 0;
906       error:
907 	ACPI_EXCEPTION((AE_INFO, status, "Could not use ECDT"));
908 	kfree(ec_ecdt);
909 	ec_ecdt = NULL;
910 
911 	return -ENODEV;
912 }
913 
914 static int __initdata acpi_fake_ecdt_enabled;
915 int __init acpi_ec_ecdt_probe(void)
916 {
917 	acpi_status status;
918 	int ret;
919 
920 	ret = acpi_ec_get_real_ecdt();
921 	/* Try to make a fake ECDT */
922 	if (ret && acpi_fake_ecdt_enabled) {
923 		ret = acpi_ec_fake_ecdt();
924 	}
925 
926 	if (ret)
927 		return 0;
928 
929 	/*
930 	 * Install GPE handler
931 	 */
932 	status = acpi_install_gpe_handler(NULL, ec_ecdt->gpe,
933 					  ACPI_GPE_EDGE_TRIGGERED,
934 					  &acpi_ec_gpe_handler, ec_ecdt);
935 	if (ACPI_FAILURE(status)) {
936 		goto error;
937 	}
938 	acpi_set_gpe_type(NULL, ec_ecdt->gpe, ACPI_GPE_TYPE_RUNTIME);
939 	acpi_enable_gpe(NULL, ec_ecdt->gpe, ACPI_NOT_ISR);
940 
941 	status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
942 						    ACPI_ADR_SPACE_EC,
943 						    &acpi_ec_space_handler,
944 						    &acpi_ec_space_setup,
945 						    ec_ecdt);
946 	if (ACPI_FAILURE(status)) {
947 		acpi_remove_gpe_handler(NULL, ec_ecdt->gpe,
948 					&acpi_ec_gpe_handler);
949 		goto error;
950 	}
951 
952 	return 0;
953 
954       error:
955 	ACPI_EXCEPTION((AE_INFO, status, "Could not use ECDT"));
956 	kfree(ec_ecdt);
957 	ec_ecdt = NULL;
958 
959 	return -ENODEV;
960 }
961 
962 static int __init acpi_ec_init(void)
963 {
964 	int result = 0;
965 
966 	if (acpi_disabled)
967 		return 0;
968 
969 	acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
970 	if (!acpi_ec_dir)
971 		return -ENODEV;
972 
973 	/* Now register the driver for the EC */
974 	result = acpi_bus_register_driver(&acpi_ec_driver);
975 	if (result < 0) {
976 		remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
977 		return -ENODEV;
978 	}
979 
980 	return result;
981 }
982 
983 subsys_initcall(acpi_ec_init);
984 
985 /* EC driver currently not unloadable */
986 #if 0
987 static void __exit acpi_ec_exit(void)
988 {
989 
990 	acpi_bus_unregister_driver(&acpi_ec_driver);
991 
992 	remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
993 
994 	return;
995 }
996 #endif				/* 0 */
997 
998 static int __init acpi_fake_ecdt_setup(char *str)
999 {
1000 	acpi_fake_ecdt_enabled = 1;
1001 	return 1;
1002 }
1003 
1004 __setup("acpi_fake_ecdt", acpi_fake_ecdt_setup);
1005 static int __init acpi_ec_set_intr_mode(char *str)
1006 {
1007 	int intr;
1008 
1009 	if (!get_option(&str, &intr))
1010 		return 0;
1011 
1012 	if (intr) {
1013 		acpi_ec_mode = EC_INTR;
1014 	} else {
1015 		acpi_ec_mode = EC_POLL;
1016 	}
1017 	acpi_ec_driver.ops.add = acpi_ec_add;
1018 	printk(KERN_NOTICE PREFIX "%s mode.\n",
1019 			  intr ? "interrupt" : "polling");
1020 
1021 	return 1;
1022 }
1023 
1024 __setup("ec_intr=", acpi_ec_set_intr_mode);
1025