xref: /openbmc/linux/drivers/acpi/ec.c (revision 7dd65feb)
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v2.1)
3  *
4  *  Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@suse.de>
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 /* Uncomment next line to get verbose printout */
30 /* #define DEBUG */
31 
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/init.h>
35 #include <linux/types.h>
36 #include <linux/delay.h>
37 #include <linux/proc_fs.h>
38 #include <linux/seq_file.h>
39 #include <linux/interrupt.h>
40 #include <linux/list.h>
41 #include <linux/spinlock.h>
42 #include <asm/io.h>
43 #include <acpi/acpi_bus.h>
44 #include <acpi/acpi_drivers.h>
45 #include <linux/dmi.h>
46 
47 #define ACPI_EC_CLASS			"embedded_controller"
48 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
49 #define ACPI_EC_FILE_INFO		"info"
50 
51 #define PREFIX				"ACPI: EC: "
52 
53 /* EC status register */
54 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
55 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
56 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
57 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
58 
59 /* EC commands */
60 enum ec_command {
61 	ACPI_EC_COMMAND_READ = 0x80,
62 	ACPI_EC_COMMAND_WRITE = 0x81,
63 	ACPI_EC_BURST_ENABLE = 0x82,
64 	ACPI_EC_BURST_DISABLE = 0x83,
65 	ACPI_EC_COMMAND_QUERY = 0x84,
66 };
67 
68 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
69 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
70 #define ACPI_EC_CDELAY		10	/* Wait 10us before polling EC */
71 #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
72 
73 #define ACPI_EC_STORM_THRESHOLD 8	/* number of false interrupts
74 					   per one transaction */
75 
76 enum {
77 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
78 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
79 	EC_FLAGS_HANDLERS_INSTALLED	/* Handlers for GPE and
80 					 * OpReg are installed */
81 };
82 
83 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
84 /* External interfaces use first EC only, so remember */
85 typedef int (*acpi_ec_query_func) (void *data);
86 
87 struct acpi_ec_query_handler {
88 	struct list_head node;
89 	acpi_ec_query_func func;
90 	acpi_handle handle;
91 	void *data;
92 	u8 query_bit;
93 };
94 
95 struct transaction {
96 	const u8 *wdata;
97 	u8 *rdata;
98 	unsigned short irq_count;
99 	u8 command;
100 	u8 wi;
101 	u8 ri;
102 	u8 wlen;
103 	u8 rlen;
104 	bool done;
105 };
106 
107 static struct acpi_ec {
108 	acpi_handle handle;
109 	unsigned long gpe;
110 	unsigned long command_addr;
111 	unsigned long data_addr;
112 	unsigned long global_lock;
113 	unsigned long flags;
114 	struct mutex lock;
115 	wait_queue_head_t wait;
116 	struct list_head list;
117 	struct transaction *curr;
118 	spinlock_t curr_lock;
119 } *boot_ec, *first_ec;
120 
121 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
122 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
123 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
124 
125 /* --------------------------------------------------------------------------
126                              Transaction Management
127    -------------------------------------------------------------------------- */
128 
129 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
130 {
131 	u8 x = inb(ec->command_addr);
132 	pr_debug(PREFIX "---> status = 0x%2.2x\n", x);
133 	return x;
134 }
135 
136 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
137 {
138 	u8 x = inb(ec->data_addr);
139 	pr_debug(PREFIX "---> data = 0x%2.2x\n", x);
140 	return x;
141 }
142 
143 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
144 {
145 	pr_debug(PREFIX "<--- command = 0x%2.2x\n", command);
146 	outb(command, ec->command_addr);
147 }
148 
149 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
150 {
151 	pr_debug(PREFIX "<--- data = 0x%2.2x\n", data);
152 	outb(data, ec->data_addr);
153 }
154 
155 static int ec_transaction_done(struct acpi_ec *ec)
156 {
157 	unsigned long flags;
158 	int ret = 0;
159 	spin_lock_irqsave(&ec->curr_lock, flags);
160 	if (!ec->curr || ec->curr->done)
161 		ret = 1;
162 	spin_unlock_irqrestore(&ec->curr_lock, flags);
163 	return ret;
164 }
165 
166 static void start_transaction(struct acpi_ec *ec)
167 {
168 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
169 	ec->curr->done = false;
170 	acpi_ec_write_cmd(ec, ec->curr->command);
171 }
172 
173 static void advance_transaction(struct acpi_ec *ec, u8 status)
174 {
175 	unsigned long flags;
176 	spin_lock_irqsave(&ec->curr_lock, flags);
177 	if (!ec->curr)
178 		goto unlock;
179 	if (ec->curr->wlen > ec->curr->wi) {
180 		if ((status & ACPI_EC_FLAG_IBF) == 0)
181 			acpi_ec_write_data(ec,
182 				ec->curr->wdata[ec->curr->wi++]);
183 		else
184 			goto err;
185 	} else if (ec->curr->rlen > ec->curr->ri) {
186 		if ((status & ACPI_EC_FLAG_OBF) == 1) {
187 			ec->curr->rdata[ec->curr->ri++] = acpi_ec_read_data(ec);
188 			if (ec->curr->rlen == ec->curr->ri)
189 				ec->curr->done = true;
190 		} else
191 			goto err;
192 	} else if (ec->curr->wlen == ec->curr->wi &&
193 		   (status & ACPI_EC_FLAG_IBF) == 0)
194 		ec->curr->done = true;
195 	goto unlock;
196 err:
197 	/* false interrupt, state didn't change */
198 	if (in_interrupt())
199 		++ec->curr->irq_count;
200 unlock:
201 	spin_unlock_irqrestore(&ec->curr_lock, flags);
202 }
203 
204 static void acpi_ec_gpe_query(void *ec_cxt);
205 
206 static int ec_check_sci(struct acpi_ec *ec, u8 state)
207 {
208 	if (state & ACPI_EC_FLAG_SCI) {
209 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
210 			return acpi_os_execute(OSL_EC_BURST_HANDLER,
211 				acpi_ec_gpe_query, ec);
212 	}
213 	return 0;
214 }
215 
216 static int ec_poll(struct acpi_ec *ec)
217 {
218 	unsigned long flags;
219 	int repeat = 2; /* number of command restarts */
220 	while (repeat--) {
221 		unsigned long delay = jiffies +
222 			msecs_to_jiffies(ACPI_EC_DELAY);
223 		do {
224 			/* don't sleep with disabled interrupts */
225 			if (EC_FLAGS_MSI || irqs_disabled()) {
226 				udelay(ACPI_EC_MSI_UDELAY);
227 				if (ec_transaction_done(ec))
228 					return 0;
229 			} else {
230 				if (wait_event_timeout(ec->wait,
231 						ec_transaction_done(ec),
232 						msecs_to_jiffies(1)))
233 					return 0;
234 			}
235 			advance_transaction(ec, acpi_ec_read_status(ec));
236 		} while (time_before(jiffies, delay));
237 		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
238 			break;
239 		pr_debug(PREFIX "controller reset, restart transaction\n");
240 		spin_lock_irqsave(&ec->curr_lock, flags);
241 		start_transaction(ec);
242 		spin_unlock_irqrestore(&ec->curr_lock, flags);
243 	}
244 	return -ETIME;
245 }
246 
247 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
248 					struct transaction *t)
249 {
250 	unsigned long tmp;
251 	int ret = 0;
252 	pr_debug(PREFIX "transaction start\n");
253 	/* disable GPE during transaction if storm is detected */
254 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
255 		acpi_disable_gpe(NULL, ec->gpe);
256 	}
257 	if (EC_FLAGS_MSI)
258 		udelay(ACPI_EC_MSI_UDELAY);
259 	/* start transaction */
260 	spin_lock_irqsave(&ec->curr_lock, tmp);
261 	/* following two actions should be kept atomic */
262 	ec->curr = t;
263 	start_transaction(ec);
264 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
265 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
266 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
267 	ret = ec_poll(ec);
268 	pr_debug(PREFIX "transaction end\n");
269 	spin_lock_irqsave(&ec->curr_lock, tmp);
270 	ec->curr = NULL;
271 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
272 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
273 		/* check if we received SCI during transaction */
274 		ec_check_sci(ec, acpi_ec_read_status(ec));
275 		/* it is safe to enable GPE outside of transaction */
276 		acpi_enable_gpe(NULL, ec->gpe);
277 	} else if (t->irq_count > ACPI_EC_STORM_THRESHOLD) {
278 		pr_info(PREFIX "GPE storm detected, "
279 			"transactions will use polling mode\n");
280 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
281 	}
282 	return ret;
283 }
284 
285 static int ec_check_ibf0(struct acpi_ec *ec)
286 {
287 	u8 status = acpi_ec_read_status(ec);
288 	return (status & ACPI_EC_FLAG_IBF) == 0;
289 }
290 
291 static int ec_wait_ibf0(struct acpi_ec *ec)
292 {
293 	unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
294 	/* interrupt wait manually if GPE mode is not active */
295 	while (time_before(jiffies, delay))
296 		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec),
297 					msecs_to_jiffies(1)))
298 			return 0;
299 	return -ETIME;
300 }
301 
302 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
303 {
304 	int status;
305 	u32 glk;
306 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
307 		return -EINVAL;
308 	if (t->rdata)
309 		memset(t->rdata, 0, t->rlen);
310 	mutex_lock(&ec->lock);
311 	if (ec->global_lock) {
312 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
313 		if (ACPI_FAILURE(status)) {
314 			status = -ENODEV;
315 			goto unlock;
316 		}
317 	}
318 	if (ec_wait_ibf0(ec)) {
319 		pr_err(PREFIX "input buffer is not empty, "
320 				"aborting transaction\n");
321 		status = -ETIME;
322 		goto end;
323 	}
324 	status = acpi_ec_transaction_unlocked(ec, t);
325 end:
326 	if (ec->global_lock)
327 		acpi_release_global_lock(glk);
328 unlock:
329 	mutex_unlock(&ec->lock);
330 	return status;
331 }
332 
333 static int acpi_ec_burst_enable(struct acpi_ec *ec)
334 {
335 	u8 d;
336 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
337 				.wdata = NULL, .rdata = &d,
338 				.wlen = 0, .rlen = 1};
339 
340 	return acpi_ec_transaction(ec, &t);
341 }
342 
343 static int acpi_ec_burst_disable(struct acpi_ec *ec)
344 {
345 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
346 				.wdata = NULL, .rdata = NULL,
347 				.wlen = 0, .rlen = 0};
348 
349 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
350 				acpi_ec_transaction(ec, &t) : 0;
351 }
352 
353 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
354 {
355 	int result;
356 	u8 d;
357 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
358 				.wdata = &address, .rdata = &d,
359 				.wlen = 1, .rlen = 1};
360 
361 	result = acpi_ec_transaction(ec, &t);
362 	*data = d;
363 	return result;
364 }
365 
366 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
367 {
368 	u8 wdata[2] = { address, data };
369 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
370 				.wdata = wdata, .rdata = NULL,
371 				.wlen = 2, .rlen = 0};
372 
373 	return acpi_ec_transaction(ec, &t);
374 }
375 
376 /*
377  * Externally callable EC access functions. For now, assume 1 EC only
378  */
379 int ec_burst_enable(void)
380 {
381 	if (!first_ec)
382 		return -ENODEV;
383 	return acpi_ec_burst_enable(first_ec);
384 }
385 
386 EXPORT_SYMBOL(ec_burst_enable);
387 
388 int ec_burst_disable(void)
389 {
390 	if (!first_ec)
391 		return -ENODEV;
392 	return acpi_ec_burst_disable(first_ec);
393 }
394 
395 EXPORT_SYMBOL(ec_burst_disable);
396 
397 int ec_read(u8 addr, u8 * val)
398 {
399 	int err;
400 	u8 temp_data;
401 
402 	if (!first_ec)
403 		return -ENODEV;
404 
405 	err = acpi_ec_read(first_ec, addr, &temp_data);
406 
407 	if (!err) {
408 		*val = temp_data;
409 		return 0;
410 	} else
411 		return err;
412 }
413 
414 EXPORT_SYMBOL(ec_read);
415 
416 int ec_write(u8 addr, u8 val)
417 {
418 	int err;
419 
420 	if (!first_ec)
421 		return -ENODEV;
422 
423 	err = acpi_ec_write(first_ec, addr, val);
424 
425 	return err;
426 }
427 
428 EXPORT_SYMBOL(ec_write);
429 
430 int ec_transaction(u8 command,
431 		   const u8 * wdata, unsigned wdata_len,
432 		   u8 * rdata, unsigned rdata_len,
433 		   int force_poll)
434 {
435 	struct transaction t = {.command = command,
436 				.wdata = wdata, .rdata = rdata,
437 				.wlen = wdata_len, .rlen = rdata_len};
438 	if (!first_ec)
439 		return -ENODEV;
440 
441 	return acpi_ec_transaction(first_ec, &t);
442 }
443 
444 EXPORT_SYMBOL(ec_transaction);
445 
446 static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
447 {
448 	int result;
449 	u8 d;
450 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
451 				.wdata = NULL, .rdata = &d,
452 				.wlen = 0, .rlen = 1};
453 	if (!ec || !data)
454 		return -EINVAL;
455 
456 	/*
457 	 * Query the EC to find out which _Qxx method we need to evaluate.
458 	 * Note that successful completion of the query causes the ACPI_EC_SCI
459 	 * bit to be cleared (and thus clearing the interrupt source).
460 	 */
461 
462 	result = acpi_ec_transaction(ec, &t);
463 	if (result)
464 		return result;
465 
466 	if (!d)
467 		return -ENODATA;
468 
469 	*data = d;
470 	return 0;
471 }
472 
473 /* --------------------------------------------------------------------------
474                                 Event Management
475    -------------------------------------------------------------------------- */
476 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
477 			      acpi_handle handle, acpi_ec_query_func func,
478 			      void *data)
479 {
480 	struct acpi_ec_query_handler *handler =
481 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
482 	if (!handler)
483 		return -ENOMEM;
484 
485 	handler->query_bit = query_bit;
486 	handler->handle = handle;
487 	handler->func = func;
488 	handler->data = data;
489 	mutex_lock(&ec->lock);
490 	list_add(&handler->node, &ec->list);
491 	mutex_unlock(&ec->lock);
492 	return 0;
493 }
494 
495 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
496 
497 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
498 {
499 	struct acpi_ec_query_handler *handler, *tmp;
500 	mutex_lock(&ec->lock);
501 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
502 		if (query_bit == handler->query_bit) {
503 			list_del(&handler->node);
504 			kfree(handler);
505 		}
506 	}
507 	mutex_unlock(&ec->lock);
508 }
509 
510 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
511 
512 static void acpi_ec_gpe_query(void *ec_cxt)
513 {
514 	struct acpi_ec *ec = ec_cxt;
515 	u8 value = 0;
516 	struct acpi_ec_query_handler *handler, copy;
517 
518 	if (!ec || acpi_ec_query(ec, &value))
519 		return;
520 	mutex_lock(&ec->lock);
521 	list_for_each_entry(handler, &ec->list, node) {
522 		if (value == handler->query_bit) {
523 			/* have custom handler for this bit */
524 			memcpy(&copy, handler, sizeof(copy));
525 			mutex_unlock(&ec->lock);
526 			if (copy.func) {
527 				copy.func(copy.data);
528 			} else if (copy.handle) {
529 				acpi_evaluate_object(copy.handle, NULL, NULL, NULL);
530 			}
531 			return;
532 		}
533 	}
534 	mutex_unlock(&ec->lock);
535 }
536 
537 static u32 acpi_ec_gpe_handler(void *data)
538 {
539 	struct acpi_ec *ec = data;
540 	u8 status;
541 
542 	pr_debug(PREFIX "~~~> interrupt\n");
543 	status = acpi_ec_read_status(ec);
544 
545 	advance_transaction(ec, status);
546 	if (ec_transaction_done(ec) && (status & ACPI_EC_FLAG_IBF) == 0)
547 		wake_up(&ec->wait);
548 	ec_check_sci(ec, status);
549 	return ACPI_INTERRUPT_HANDLED;
550 }
551 
552 /* --------------------------------------------------------------------------
553                              Address Space Management
554    -------------------------------------------------------------------------- */
555 
556 static acpi_status
557 acpi_ec_space_handler(u32 function, acpi_physical_address address,
558 		      u32 bits, acpi_integer *value,
559 		      void *handler_context, void *region_context)
560 {
561 	struct acpi_ec *ec = handler_context;
562 	int result = 0, i;
563 	u8 temp = 0;
564 
565 	if ((address > 0xFF) || !value || !handler_context)
566 		return AE_BAD_PARAMETER;
567 
568 	if (function != ACPI_READ && function != ACPI_WRITE)
569 		return AE_BAD_PARAMETER;
570 
571 	if (bits != 8 && acpi_strict)
572 		return AE_BAD_PARAMETER;
573 
574 	if (EC_FLAGS_MSI)
575 		acpi_ec_burst_enable(ec);
576 
577 	if (function == ACPI_READ) {
578 		result = acpi_ec_read(ec, address, &temp);
579 		*value = temp;
580 	} else {
581 		temp = 0xff & (*value);
582 		result = acpi_ec_write(ec, address, temp);
583 	}
584 
585 	for (i = 8; unlikely(bits - i > 0); i += 8) {
586 		++address;
587 		if (function == ACPI_READ) {
588 			result = acpi_ec_read(ec, address, &temp);
589 			(*value) |= ((acpi_integer)temp) << i;
590 		} else {
591 			temp = 0xff & ((*value) >> i);
592 			result = acpi_ec_write(ec, address, temp);
593 		}
594 	}
595 
596 	if (EC_FLAGS_MSI)
597 		acpi_ec_burst_disable(ec);
598 
599 	switch (result) {
600 	case -EINVAL:
601 		return AE_BAD_PARAMETER;
602 		break;
603 	case -ENODEV:
604 		return AE_NOT_FOUND;
605 		break;
606 	case -ETIME:
607 		return AE_TIME;
608 		break;
609 	default:
610 		return AE_OK;
611 	}
612 }
613 
614 /* --------------------------------------------------------------------------
615                               FS Interface (/proc)
616    -------------------------------------------------------------------------- */
617 
618 static struct proc_dir_entry *acpi_ec_dir;
619 
620 static int acpi_ec_read_info(struct seq_file *seq, void *offset)
621 {
622 	struct acpi_ec *ec = seq->private;
623 
624 	if (!ec)
625 		goto end;
626 
627 	seq_printf(seq, "gpe:\t\t\t0x%02x\n", (u32) ec->gpe);
628 	seq_printf(seq, "ports:\t\t\t0x%02x, 0x%02x\n",
629 		   (unsigned)ec->command_addr, (unsigned)ec->data_addr);
630 	seq_printf(seq, "use global lock:\t%s\n",
631 		   ec->global_lock ? "yes" : "no");
632       end:
633 	return 0;
634 }
635 
636 static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
637 {
638 	return single_open(file, acpi_ec_read_info, PDE(inode)->data);
639 }
640 
641 static const struct file_operations acpi_ec_info_ops = {
642 	.open = acpi_ec_info_open_fs,
643 	.read = seq_read,
644 	.llseek = seq_lseek,
645 	.release = single_release,
646 	.owner = THIS_MODULE,
647 };
648 
649 static int acpi_ec_add_fs(struct acpi_device *device)
650 {
651 	struct proc_dir_entry *entry = NULL;
652 
653 	if (!acpi_device_dir(device)) {
654 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
655 						     acpi_ec_dir);
656 		if (!acpi_device_dir(device))
657 			return -ENODEV;
658 	}
659 
660 	entry = proc_create_data(ACPI_EC_FILE_INFO, S_IRUGO,
661 				 acpi_device_dir(device),
662 				 &acpi_ec_info_ops, acpi_driver_data(device));
663 	if (!entry)
664 		return -ENODEV;
665 	return 0;
666 }
667 
668 static int acpi_ec_remove_fs(struct acpi_device *device)
669 {
670 
671 	if (acpi_device_dir(device)) {
672 		remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
673 		remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
674 		acpi_device_dir(device) = NULL;
675 	}
676 
677 	return 0;
678 }
679 
680 /* --------------------------------------------------------------------------
681                                Driver Interface
682    -------------------------------------------------------------------------- */
683 static acpi_status
684 ec_parse_io_ports(struct acpi_resource *resource, void *context);
685 
686 static struct acpi_ec *make_acpi_ec(void)
687 {
688 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
689 	if (!ec)
690 		return NULL;
691 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
692 	mutex_init(&ec->lock);
693 	init_waitqueue_head(&ec->wait);
694 	INIT_LIST_HEAD(&ec->list);
695 	spin_lock_init(&ec->curr_lock);
696 	return ec;
697 }
698 
699 static acpi_status
700 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
701 			       void *context, void **return_value)
702 {
703 	char node_name[5];
704 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
705 	struct acpi_ec *ec = context;
706 	int value = 0;
707 	acpi_status status;
708 
709 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
710 
711 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
712 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
713 	}
714 	return AE_OK;
715 }
716 
717 static acpi_status
718 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
719 {
720 	acpi_status status;
721 	unsigned long long tmp = 0;
722 
723 	struct acpi_ec *ec = context;
724 
725 	/* clear addr values, ec_parse_io_ports depend on it */
726 	ec->command_addr = ec->data_addr = 0;
727 
728 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
729 				     ec_parse_io_ports, ec);
730 	if (ACPI_FAILURE(status))
731 		return status;
732 
733 	/* Get GPE bit assignment (EC events). */
734 	/* TODO: Add support for _GPE returning a package */
735 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
736 	if (ACPI_FAILURE(status))
737 		return status;
738 	ec->gpe = tmp;
739 	/* Use the global lock for all EC transactions? */
740 	tmp = 0;
741 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
742 	ec->global_lock = tmp;
743 	ec->handle = handle;
744 	return AE_CTRL_TERMINATE;
745 }
746 
747 static int ec_install_handlers(struct acpi_ec *ec)
748 {
749 	acpi_status status;
750 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
751 		return 0;
752 	status = acpi_install_gpe_handler(NULL, ec->gpe,
753 				  ACPI_GPE_EDGE_TRIGGERED,
754 				  &acpi_ec_gpe_handler, ec);
755 	if (ACPI_FAILURE(status))
756 		return -ENODEV;
757 	acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
758 	acpi_enable_gpe(NULL, ec->gpe);
759 	status = acpi_install_address_space_handler(ec->handle,
760 						    ACPI_ADR_SPACE_EC,
761 						    &acpi_ec_space_handler,
762 						    NULL, ec);
763 	if (ACPI_FAILURE(status)) {
764 		if (status == AE_NOT_FOUND) {
765 			/*
766 			 * Maybe OS fails in evaluating the _REG object.
767 			 * The AE_NOT_FOUND error will be ignored and OS
768 			 * continue to initialize EC.
769 			 */
770 			printk(KERN_ERR "Fail in evaluating the _REG object"
771 				" of EC device. Broken bios is suspected.\n");
772 		} else {
773 			acpi_remove_gpe_handler(NULL, ec->gpe,
774 				&acpi_ec_gpe_handler);
775 			return -ENODEV;
776 		}
777 	}
778 
779 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
780 	return 0;
781 }
782 
783 static void ec_remove_handlers(struct acpi_ec *ec)
784 {
785 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
786 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
787 		pr_err(PREFIX "failed to remove space handler\n");
788 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
789 				&acpi_ec_gpe_handler)))
790 		pr_err(PREFIX "failed to remove gpe handler\n");
791 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
792 }
793 
794 static int acpi_ec_add(struct acpi_device *device)
795 {
796 	struct acpi_ec *ec = NULL;
797 	int ret;
798 
799 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
800 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
801 
802 	/* Check for boot EC */
803 	if (boot_ec &&
804 	    (boot_ec->handle == device->handle ||
805 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
806 		ec = boot_ec;
807 		boot_ec = NULL;
808 	} else {
809 		ec = make_acpi_ec();
810 		if (!ec)
811 			return -ENOMEM;
812 	}
813 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
814 		AE_CTRL_TERMINATE) {
815 			kfree(ec);
816 			return -EINVAL;
817 	}
818 
819 	ec->handle = device->handle;
820 
821 	/* Find and register all query methods */
822 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
823 			    acpi_ec_register_query_methods, NULL, ec, NULL);
824 
825 	if (!first_ec)
826 		first_ec = ec;
827 	device->driver_data = ec;
828 	acpi_ec_add_fs(device);
829 	pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
830 			  ec->gpe, ec->command_addr, ec->data_addr);
831 
832 	ret = ec_install_handlers(ec);
833 
834 	/* EC is fully operational, allow queries */
835 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
836 	return ret;
837 }
838 
839 static int acpi_ec_remove(struct acpi_device *device, int type)
840 {
841 	struct acpi_ec *ec;
842 	struct acpi_ec_query_handler *handler, *tmp;
843 
844 	if (!device)
845 		return -EINVAL;
846 
847 	ec = acpi_driver_data(device);
848 	ec_remove_handlers(ec);
849 	mutex_lock(&ec->lock);
850 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
851 		list_del(&handler->node);
852 		kfree(handler);
853 	}
854 	mutex_unlock(&ec->lock);
855 	acpi_ec_remove_fs(device);
856 	device->driver_data = NULL;
857 	if (ec == first_ec)
858 		first_ec = NULL;
859 	kfree(ec);
860 	return 0;
861 }
862 
863 static acpi_status
864 ec_parse_io_ports(struct acpi_resource *resource, void *context)
865 {
866 	struct acpi_ec *ec = context;
867 
868 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
869 		return AE_OK;
870 
871 	/*
872 	 * The first address region returned is the data port, and
873 	 * the second address region returned is the status/command
874 	 * port.
875 	 */
876 	if (ec->data_addr == 0)
877 		ec->data_addr = resource->data.io.minimum;
878 	else if (ec->command_addr == 0)
879 		ec->command_addr = resource->data.io.minimum;
880 	else
881 		return AE_CTRL_TERMINATE;
882 
883 	return AE_OK;
884 }
885 
886 int __init acpi_boot_ec_enable(void)
887 {
888 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
889 		return 0;
890 	if (!ec_install_handlers(boot_ec)) {
891 		first_ec = boot_ec;
892 		return 0;
893 	}
894 	return -EFAULT;
895 }
896 
897 static const struct acpi_device_id ec_device_ids[] = {
898 	{"PNP0C09", 0},
899 	{"", 0},
900 };
901 
902 /* Some BIOS do not survive early DSDT scan, skip it */
903 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
904 {
905 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
906 	return 0;
907 }
908 
909 /* ASUStek often supplies us with broken ECDT, validate it */
910 static int ec_validate_ecdt(const struct dmi_system_id *id)
911 {
912 	EC_FLAGS_VALIDATE_ECDT = 1;
913 	return 0;
914 }
915 
916 /* MSI EC needs special treatment, enable it */
917 static int ec_flag_msi(const struct dmi_system_id *id)
918 {
919 	printk(KERN_DEBUG PREFIX "Detected MSI hardware, enabling workarounds.\n");
920 	EC_FLAGS_MSI = 1;
921 	EC_FLAGS_VALIDATE_ECDT = 1;
922 	return 0;
923 }
924 
925 static struct dmi_system_id __initdata ec_dmi_table[] = {
926 	{
927 	ec_skip_dsdt_scan, "Compal JFL92", {
928 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
929 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
930 	{
931 	ec_flag_msi, "MSI hardware", {
932 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
933 	{
934 	ec_flag_msi, "MSI hardware", {
935 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
936 	{
937 	ec_flag_msi, "MSI hardware", {
938 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
939 	{
940 	ec_validate_ecdt, "ASUS hardware", {
941 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
942 	{},
943 };
944 
945 
946 int __init acpi_ec_ecdt_probe(void)
947 {
948 	acpi_status status;
949 	struct acpi_ec *saved_ec = NULL;
950 	struct acpi_table_ecdt *ecdt_ptr;
951 
952 	boot_ec = make_acpi_ec();
953 	if (!boot_ec)
954 		return -ENOMEM;
955 	/*
956 	 * Generate a boot ec context
957 	 */
958 	dmi_check_system(ec_dmi_table);
959 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
960 				(struct acpi_table_header **)&ecdt_ptr);
961 	if (ACPI_SUCCESS(status)) {
962 		pr_info(PREFIX "EC description table is found, configuring boot EC\n");
963 		boot_ec->command_addr = ecdt_ptr->control.address;
964 		boot_ec->data_addr = ecdt_ptr->data.address;
965 		boot_ec->gpe = ecdt_ptr->gpe;
966 		boot_ec->handle = ACPI_ROOT_OBJECT;
967 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
968 		/* Don't trust ECDT, which comes from ASUSTek */
969 		if (!EC_FLAGS_VALIDATE_ECDT)
970 			goto install;
971 		saved_ec = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
972 		if (!saved_ec)
973 			return -ENOMEM;
974 		memcpy(saved_ec, boot_ec, sizeof(struct acpi_ec));
975 	/* fall through */
976 	}
977 
978 	if (EC_FLAGS_SKIP_DSDT_SCAN)
979 		return -ENODEV;
980 
981 	/* This workaround is needed only on some broken machines,
982 	 * which require early EC, but fail to provide ECDT */
983 	printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
984 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
985 					boot_ec, NULL);
986 	/* Check that acpi_get_devices actually find something */
987 	if (ACPI_FAILURE(status) || !boot_ec->handle)
988 		goto error;
989 	if (saved_ec) {
990 		/* try to find good ECDT from ASUSTek */
991 		if (saved_ec->command_addr != boot_ec->command_addr ||
992 		    saved_ec->data_addr != boot_ec->data_addr ||
993 		    saved_ec->gpe != boot_ec->gpe ||
994 		    saved_ec->handle != boot_ec->handle)
995 			pr_info(PREFIX "ASUSTek keeps feeding us with broken "
996 			"ECDT tables, which are very hard to workaround. "
997 			"Trying to use DSDT EC info instead. Please send "
998 			"output of acpidump to linux-acpi@vger.kernel.org\n");
999 		kfree(saved_ec);
1000 		saved_ec = NULL;
1001 	} else {
1002 		/* We really need to limit this workaround, the only ASUS,
1003 		* which needs it, has fake EC._INI method, so use it as flag.
1004 		* Keep boot_ec struct as it will be needed soon.
1005 		*/
1006 		acpi_handle dummy;
1007 		if (!dmi_name_in_vendors("ASUS") ||
1008 		    ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI",
1009 							&dummy)))
1010 			return -ENODEV;
1011 	}
1012 install:
1013 	if (!ec_install_handlers(boot_ec)) {
1014 		first_ec = boot_ec;
1015 		return 0;
1016 	}
1017 error:
1018 	kfree(boot_ec);
1019 	boot_ec = NULL;
1020 	return -ENODEV;
1021 }
1022 
1023 static int acpi_ec_suspend(struct acpi_device *device, pm_message_t state)
1024 {
1025 	struct acpi_ec *ec = acpi_driver_data(device);
1026 	/* Stop using GPE */
1027 	acpi_disable_gpe(NULL, ec->gpe);
1028 	return 0;
1029 }
1030 
1031 static int acpi_ec_resume(struct acpi_device *device)
1032 {
1033 	struct acpi_ec *ec = acpi_driver_data(device);
1034 	/* Enable use of GPE back */
1035 	acpi_enable_gpe(NULL, ec->gpe);
1036 	return 0;
1037 }
1038 
1039 static struct acpi_driver acpi_ec_driver = {
1040 	.name = "ec",
1041 	.class = ACPI_EC_CLASS,
1042 	.ids = ec_device_ids,
1043 	.ops = {
1044 		.add = acpi_ec_add,
1045 		.remove = acpi_ec_remove,
1046 		.suspend = acpi_ec_suspend,
1047 		.resume = acpi_ec_resume,
1048 		},
1049 };
1050 
1051 int __init acpi_ec_init(void)
1052 {
1053 	int result = 0;
1054 
1055 	acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
1056 	if (!acpi_ec_dir)
1057 		return -ENODEV;
1058 
1059 	/* Now register the driver for the EC */
1060 	result = acpi_bus_register_driver(&acpi_ec_driver);
1061 	if (result < 0) {
1062 		remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1063 		return -ENODEV;
1064 	}
1065 
1066 	return result;
1067 }
1068 
1069 /* EC driver currently not unloadable */
1070 #if 0
1071 static void __exit acpi_ec_exit(void)
1072 {
1073 
1074 	acpi_bus_unregister_driver(&acpi_ec_driver);
1075 
1076 	remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1077 
1078 	return;
1079 }
1080 #endif	/* 0 */
1081