xref: /openbmc/linux/drivers/acpi/ec.c (revision 20ff1cb5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ec.c - ACPI Embedded Controller Driver (v3)
4  *
5  *  Copyright (C) 2001-2015 Intel Corporation
6  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
7  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
8  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
9  *            2004       Luming Yu <luming.yu@intel.com>
10  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
11  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
12  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
13  */
14 
15 /* Uncomment next line to get verbose printout */
16 /* #define DEBUG */
17 #define pr_fmt(fmt) "ACPI: EC: " fmt
18 
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/types.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/list.h>
26 #include <linux/spinlock.h>
27 #include <linux/slab.h>
28 #include <linux/suspend.h>
29 #include <linux/acpi.h>
30 #include <linux/dmi.h>
31 #include <asm/io.h>
32 
33 #include "internal.h"
34 
35 #define ACPI_EC_CLASS			"embedded_controller"
36 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
37 #define ACPI_EC_FILE_INFO		"info"
38 
39 /* EC status register */
40 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
41 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
42 #define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
43 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
44 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
45 
46 /*
47  * The SCI_EVT clearing timing is not defined by the ACPI specification.
48  * This leads to lots of practical timing issues for the host EC driver.
49  * The following variations are defined (from the target EC firmware's
50  * perspective):
51  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
52  *         target can clear SCI_EVT at any time so long as the host can see
53  *         the indication by reading the status register (EC_SC). So the
54  *         host should re-check SCI_EVT after the first time the SCI_EVT
55  *         indication is seen, which is the same time the query request
56  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
57  *         at any later time could indicate another event. Normally such
58  *         kind of EC firmware has implemented an event queue and will
59  *         return 0x00 to indicate "no outstanding event".
60  * QUERY: After seeing the query request (QR_EC) written to the command
61  *        register (EC_CMD) by the host and having prepared the responding
62  *        event value in the data register (EC_DATA), the target can safely
63  *        clear SCI_EVT because the target can confirm that the current
64  *        event is being handled by the host. The host then should check
65  *        SCI_EVT right after reading the event response from the data
66  *        register (EC_DATA).
67  * EVENT: After seeing the event response read from the data register
68  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
69  *        target requires time to notice the change in the data register
70  *        (EC_DATA), the host may be required to wait additional guarding
71  *        time before checking the SCI_EVT again. Such guarding may not be
72  *        necessary if the host is notified via another IRQ.
73  */
74 #define ACPI_EC_EVT_TIMING_STATUS	0x00
75 #define ACPI_EC_EVT_TIMING_QUERY	0x01
76 #define ACPI_EC_EVT_TIMING_EVENT	0x02
77 
78 /* EC commands */
79 enum ec_command {
80 	ACPI_EC_COMMAND_READ = 0x80,
81 	ACPI_EC_COMMAND_WRITE = 0x81,
82 	ACPI_EC_BURST_ENABLE = 0x82,
83 	ACPI_EC_BURST_DISABLE = 0x83,
84 	ACPI_EC_COMMAND_QUERY = 0x84,
85 };
86 
87 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
88 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
89 #define ACPI_EC_UDELAY_POLL	550	/* Wait 1ms for EC transaction polling */
90 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
91 					 * when trying to clear the EC */
92 #define ACPI_EC_MAX_QUERIES	16	/* Maximum number of parallel queries */
93 
94 enum {
95 	EC_FLAGS_QUERY_ENABLED,		/* Query is enabled */
96 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
97 	EC_FLAGS_QUERY_GUARDING,	/* Guard for SCI_EVT check */
98 	EC_FLAGS_GPE_HANDLER_INSTALLED,	/* GPE handler installed */
99 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
100 	EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
101 	EC_FLAGS_STARTED,		/* Driver is started */
102 	EC_FLAGS_STOPPED,		/* Driver is stopped */
103 	EC_FLAGS_GPE_MASKED,		/* GPE masked */
104 };
105 
106 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
107 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
108 
109 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
110 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
111 module_param(ec_delay, uint, 0644);
112 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
113 
114 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
115 module_param(ec_max_queries, uint, 0644);
116 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
117 
118 static bool ec_busy_polling __read_mostly;
119 module_param(ec_busy_polling, bool, 0644);
120 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
121 
122 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
123 module_param(ec_polling_guard, uint, 0644);
124 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
125 
126 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
127 
128 /*
129  * If the number of false interrupts per one transaction exceeds
130  * this threshold, will think there is a GPE storm happened and
131  * will disable the GPE for normal transaction.
132  */
133 static unsigned int ec_storm_threshold  __read_mostly = 8;
134 module_param(ec_storm_threshold, uint, 0644);
135 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
136 
137 static bool ec_freeze_events __read_mostly = false;
138 module_param(ec_freeze_events, bool, 0644);
139 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
140 
141 static bool ec_no_wakeup __read_mostly;
142 module_param(ec_no_wakeup, bool, 0644);
143 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
144 
145 struct acpi_ec_query_handler {
146 	struct list_head node;
147 	acpi_ec_query_func func;
148 	acpi_handle handle;
149 	void *data;
150 	u8 query_bit;
151 	struct kref kref;
152 };
153 
154 struct transaction {
155 	const u8 *wdata;
156 	u8 *rdata;
157 	unsigned short irq_count;
158 	u8 command;
159 	u8 wi;
160 	u8 ri;
161 	u8 wlen;
162 	u8 rlen;
163 	u8 flags;
164 };
165 
166 struct acpi_ec_query {
167 	struct transaction transaction;
168 	struct work_struct work;
169 	struct acpi_ec_query_handler *handler;
170 };
171 
172 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
173 static void advance_transaction(struct acpi_ec *ec);
174 static void acpi_ec_event_handler(struct work_struct *work);
175 static void acpi_ec_event_processor(struct work_struct *work);
176 
177 struct acpi_ec *first_ec;
178 EXPORT_SYMBOL(first_ec);
179 
180 static struct acpi_ec *boot_ec;
181 static bool boot_ec_is_ecdt = false;
182 static struct workqueue_struct *ec_query_wq;
183 
184 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
185 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
186 static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
187 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
188 
189 /* --------------------------------------------------------------------------
190  *                           Logging/Debugging
191  * -------------------------------------------------------------------------- */
192 
193 /*
194  * Splitters used by the developers to track the boundary of the EC
195  * handling processes.
196  */
197 #ifdef DEBUG
198 #define EC_DBG_SEP	" "
199 #define EC_DBG_DRV	"+++++"
200 #define EC_DBG_STM	"====="
201 #define EC_DBG_REQ	"*****"
202 #define EC_DBG_EVT	"#####"
203 #else
204 #define EC_DBG_SEP	""
205 #define EC_DBG_DRV
206 #define EC_DBG_STM
207 #define EC_DBG_REQ
208 #define EC_DBG_EVT
209 #endif
210 
211 #define ec_log_raw(fmt, ...) \
212 	pr_info(fmt "\n", ##__VA_ARGS__)
213 #define ec_dbg_raw(fmt, ...) \
214 	pr_debug(fmt "\n", ##__VA_ARGS__)
215 #define ec_log(filter, fmt, ...) \
216 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
217 #define ec_dbg(filter, fmt, ...) \
218 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
219 
220 #define ec_log_drv(fmt, ...) \
221 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
222 #define ec_dbg_drv(fmt, ...) \
223 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
224 #define ec_dbg_stm(fmt, ...) \
225 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
226 #define ec_dbg_req(fmt, ...) \
227 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
228 #define ec_dbg_evt(fmt, ...) \
229 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
230 #define ec_dbg_ref(ec, fmt, ...) \
231 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
232 
233 /* --------------------------------------------------------------------------
234  *                           Device Flags
235  * -------------------------------------------------------------------------- */
236 
237 static bool acpi_ec_started(struct acpi_ec *ec)
238 {
239 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
240 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
241 }
242 
243 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
244 {
245 	/*
246 	 * There is an OSPM early stage logic. During the early stages
247 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
248 	 * the EC transactions are allowed to be performed.
249 	 */
250 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
251 		return false;
252 	/*
253 	 * However, disabling the event handling is experimental for late
254 	 * stage (suspend), and is controlled by the boot parameter of
255 	 * "ec_freeze_events":
256 	 * 1. true:  The EC event handling is disabled before entering
257 	 *           the noirq stage.
258 	 * 2. false: The EC event handling is automatically disabled as
259 	 *           soon as the EC driver is stopped.
260 	 */
261 	if (ec_freeze_events)
262 		return acpi_ec_started(ec);
263 	else
264 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
265 }
266 
267 static bool acpi_ec_flushed(struct acpi_ec *ec)
268 {
269 	return ec->reference_count == 1;
270 }
271 
272 /* --------------------------------------------------------------------------
273  *                           EC Registers
274  * -------------------------------------------------------------------------- */
275 
276 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
277 {
278 	u8 x = inb(ec->command_addr);
279 
280 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
281 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
282 		   x,
283 		   !!(x & ACPI_EC_FLAG_SCI),
284 		   !!(x & ACPI_EC_FLAG_BURST),
285 		   !!(x & ACPI_EC_FLAG_CMD),
286 		   !!(x & ACPI_EC_FLAG_IBF),
287 		   !!(x & ACPI_EC_FLAG_OBF));
288 	return x;
289 }
290 
291 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
292 {
293 	u8 x = inb(ec->data_addr);
294 
295 	ec->timestamp = jiffies;
296 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
297 	return x;
298 }
299 
300 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
301 {
302 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
303 	outb(command, ec->command_addr);
304 	ec->timestamp = jiffies;
305 }
306 
307 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
308 {
309 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
310 	outb(data, ec->data_addr);
311 	ec->timestamp = jiffies;
312 }
313 
314 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
315 static const char *acpi_ec_cmd_string(u8 cmd)
316 {
317 	switch (cmd) {
318 	case 0x80:
319 		return "RD_EC";
320 	case 0x81:
321 		return "WR_EC";
322 	case 0x82:
323 		return "BE_EC";
324 	case 0x83:
325 		return "BD_EC";
326 	case 0x84:
327 		return "QR_EC";
328 	}
329 	return "UNKNOWN";
330 }
331 #else
332 #define acpi_ec_cmd_string(cmd)		"UNDEF"
333 #endif
334 
335 /* --------------------------------------------------------------------------
336  *                           GPE Registers
337  * -------------------------------------------------------------------------- */
338 
339 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
340 {
341 	acpi_event_status gpe_status = 0;
342 
343 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
344 	return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
345 }
346 
347 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
348 {
349 	if (open)
350 		acpi_enable_gpe(NULL, ec->gpe);
351 	else {
352 		BUG_ON(ec->reference_count < 1);
353 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
354 	}
355 	if (acpi_ec_is_gpe_raised(ec)) {
356 		/*
357 		 * On some platforms, EN=1 writes cannot trigger GPE. So
358 		 * software need to manually trigger a pseudo GPE event on
359 		 * EN=1 writes.
360 		 */
361 		ec_dbg_raw("Polling quirk");
362 		advance_transaction(ec);
363 	}
364 }
365 
366 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
367 {
368 	if (close)
369 		acpi_disable_gpe(NULL, ec->gpe);
370 	else {
371 		BUG_ON(ec->reference_count < 1);
372 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
373 	}
374 }
375 
376 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
377 {
378 	/*
379 	 * GPE STS is a W1C register, which means:
380 	 * 1. Software can clear it without worrying about clearing other
381 	 *    GPEs' STS bits when the hardware sets them in parallel.
382 	 * 2. As long as software can ensure only clearing it when it is
383 	 *    set, hardware won't set it in parallel.
384 	 * So software can clear GPE in any contexts.
385 	 * Warning: do not move the check into advance_transaction() as the
386 	 * EC commands will be sent without GPE raised.
387 	 */
388 	if (!acpi_ec_is_gpe_raised(ec))
389 		return;
390 	acpi_clear_gpe(NULL, ec->gpe);
391 }
392 
393 /* --------------------------------------------------------------------------
394  *                           Transaction Management
395  * -------------------------------------------------------------------------- */
396 
397 static void acpi_ec_submit_request(struct acpi_ec *ec)
398 {
399 	ec->reference_count++;
400 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
401 	    ec->reference_count == 1)
402 		acpi_ec_enable_gpe(ec, true);
403 }
404 
405 static void acpi_ec_complete_request(struct acpi_ec *ec)
406 {
407 	bool flushed = false;
408 
409 	ec->reference_count--;
410 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
411 	    ec->reference_count == 0)
412 		acpi_ec_disable_gpe(ec, true);
413 	flushed = acpi_ec_flushed(ec);
414 	if (flushed)
415 		wake_up(&ec->wait);
416 }
417 
418 static void acpi_ec_mask_gpe(struct acpi_ec *ec)
419 {
420 	if (!test_bit(EC_FLAGS_GPE_MASKED, &ec->flags)) {
421 		acpi_ec_disable_gpe(ec, false);
422 		ec_dbg_drv("Polling enabled");
423 		set_bit(EC_FLAGS_GPE_MASKED, &ec->flags);
424 	}
425 }
426 
427 static void acpi_ec_unmask_gpe(struct acpi_ec *ec)
428 {
429 	if (test_bit(EC_FLAGS_GPE_MASKED, &ec->flags)) {
430 		clear_bit(EC_FLAGS_GPE_MASKED, &ec->flags);
431 		acpi_ec_enable_gpe(ec, false);
432 		ec_dbg_drv("Polling disabled");
433 	}
434 }
435 
436 /*
437  * acpi_ec_submit_flushable_request() - Increase the reference count unless
438  *                                      the flush operation is not in
439  *                                      progress
440  * @ec: the EC device
441  *
442  * This function must be used before taking a new action that should hold
443  * the reference count.  If this function returns false, then the action
444  * must be discarded or it will prevent the flush operation from being
445  * completed.
446  */
447 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
448 {
449 	if (!acpi_ec_started(ec))
450 		return false;
451 	acpi_ec_submit_request(ec);
452 	return true;
453 }
454 
455 static void acpi_ec_submit_query(struct acpi_ec *ec)
456 {
457 	acpi_ec_mask_gpe(ec);
458 	if (!acpi_ec_event_enabled(ec))
459 		return;
460 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
461 		ec_dbg_evt("Command(%s) submitted/blocked",
462 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
463 		ec->nr_pending_queries++;
464 		schedule_work(&ec->work);
465 	}
466 }
467 
468 static void acpi_ec_complete_query(struct acpi_ec *ec)
469 {
470 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
471 		ec_dbg_evt("Command(%s) unblocked",
472 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
473 	acpi_ec_unmask_gpe(ec);
474 }
475 
476 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
477 {
478 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
479 		ec_log_drv("event unblocked");
480 	/*
481 	 * Unconditionally invoke this once after enabling the event
482 	 * handling mechanism to detect the pending events.
483 	 */
484 	advance_transaction(ec);
485 }
486 
487 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
488 {
489 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
490 		ec_log_drv("event blocked");
491 }
492 
493 /*
494  * Process _Q events that might have accumulated in the EC.
495  * Run with locked ec mutex.
496  */
497 static void acpi_ec_clear(struct acpi_ec *ec)
498 {
499 	int i, status;
500 	u8 value = 0;
501 
502 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
503 		status = acpi_ec_query(ec, &value);
504 		if (status || !value)
505 			break;
506 	}
507 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
508 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
509 	else
510 		pr_info("%d stale EC events cleared\n", i);
511 }
512 
513 static void acpi_ec_enable_event(struct acpi_ec *ec)
514 {
515 	unsigned long flags;
516 
517 	spin_lock_irqsave(&ec->lock, flags);
518 	if (acpi_ec_started(ec))
519 		__acpi_ec_enable_event(ec);
520 	spin_unlock_irqrestore(&ec->lock, flags);
521 
522 	/* Drain additional events if hardware requires that */
523 	if (EC_FLAGS_CLEAR_ON_RESUME)
524 		acpi_ec_clear(ec);
525 }
526 
527 #ifdef CONFIG_PM_SLEEP
528 static bool acpi_ec_query_flushed(struct acpi_ec *ec)
529 {
530 	bool flushed;
531 	unsigned long flags;
532 
533 	spin_lock_irqsave(&ec->lock, flags);
534 	flushed = !ec->nr_pending_queries;
535 	spin_unlock_irqrestore(&ec->lock, flags);
536 	return flushed;
537 }
538 
539 static void __acpi_ec_flush_event(struct acpi_ec *ec)
540 {
541 	/*
542 	 * When ec_freeze_events is true, we need to flush events in
543 	 * the proper position before entering the noirq stage.
544 	 */
545 	wait_event(ec->wait, acpi_ec_query_flushed(ec));
546 	if (ec_query_wq)
547 		flush_workqueue(ec_query_wq);
548 }
549 
550 static void acpi_ec_disable_event(struct acpi_ec *ec)
551 {
552 	unsigned long flags;
553 
554 	spin_lock_irqsave(&ec->lock, flags);
555 	__acpi_ec_disable_event(ec);
556 	spin_unlock_irqrestore(&ec->lock, flags);
557 	__acpi_ec_flush_event(ec);
558 }
559 
560 void acpi_ec_flush_work(void)
561 {
562 	if (first_ec)
563 		__acpi_ec_flush_event(first_ec);
564 
565 	flush_scheduled_work();
566 }
567 #endif /* CONFIG_PM_SLEEP */
568 
569 static bool acpi_ec_guard_event(struct acpi_ec *ec)
570 {
571 	bool guarded = true;
572 	unsigned long flags;
573 
574 	spin_lock_irqsave(&ec->lock, flags);
575 	/*
576 	 * If firmware SCI_EVT clearing timing is "event", we actually
577 	 * don't know when the SCI_EVT will be cleared by firmware after
578 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
579 	 * acceptable period.
580 	 *
581 	 * The guarding period begins when EC_FLAGS_QUERY_PENDING is
582 	 * flagged, which means SCI_EVT check has just been performed.
583 	 * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
584 	 * guarding should have already been performed (via
585 	 * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
586 	 * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
587 	 * ACPI_EC_COMMAND_POLL state immediately.
588 	 */
589 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
590 	    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
591 	    !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
592 	    (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
593 		guarded = false;
594 	spin_unlock_irqrestore(&ec->lock, flags);
595 	return guarded;
596 }
597 
598 static int ec_transaction_polled(struct acpi_ec *ec)
599 {
600 	unsigned long flags;
601 	int ret = 0;
602 
603 	spin_lock_irqsave(&ec->lock, flags);
604 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
605 		ret = 1;
606 	spin_unlock_irqrestore(&ec->lock, flags);
607 	return ret;
608 }
609 
610 static int ec_transaction_completed(struct acpi_ec *ec)
611 {
612 	unsigned long flags;
613 	int ret = 0;
614 
615 	spin_lock_irqsave(&ec->lock, flags);
616 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
617 		ret = 1;
618 	spin_unlock_irqrestore(&ec->lock, flags);
619 	return ret;
620 }
621 
622 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
623 {
624 	ec->curr->flags |= flag;
625 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
626 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
627 		    flag == ACPI_EC_COMMAND_POLL)
628 			acpi_ec_complete_query(ec);
629 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
630 		    flag == ACPI_EC_COMMAND_COMPLETE)
631 			acpi_ec_complete_query(ec);
632 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
633 		    flag == ACPI_EC_COMMAND_COMPLETE)
634 			set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
635 	}
636 }
637 
638 static void advance_transaction(struct acpi_ec *ec)
639 {
640 	struct transaction *t;
641 	u8 status;
642 	bool wakeup = false;
643 
644 	ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
645 		   smp_processor_id());
646 	/*
647 	 * By always clearing STS before handling all indications, we can
648 	 * ensure a hardware STS 0->1 change after this clearing can always
649 	 * trigger a GPE interrupt.
650 	 */
651 	acpi_ec_clear_gpe(ec);
652 	status = acpi_ec_read_status(ec);
653 	t = ec->curr;
654 	/*
655 	 * Another IRQ or a guarded polling mode advancement is detected,
656 	 * the next QR_EC submission is then allowed.
657 	 */
658 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
659 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
660 		    (!ec->nr_pending_queries ||
661 		     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
662 			clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
663 			acpi_ec_complete_query(ec);
664 		}
665 	}
666 	if (!t)
667 		goto err;
668 	if (t->flags & ACPI_EC_COMMAND_POLL) {
669 		if (t->wlen > t->wi) {
670 			if ((status & ACPI_EC_FLAG_IBF) == 0)
671 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
672 			else
673 				goto err;
674 		} else if (t->rlen > t->ri) {
675 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
676 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
677 				if (t->rlen == t->ri) {
678 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
679 					if (t->command == ACPI_EC_COMMAND_QUERY)
680 						ec_dbg_evt("Command(%s) completed by hardware",
681 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
682 					wakeup = true;
683 				}
684 			} else
685 				goto err;
686 		} else if (t->wlen == t->wi &&
687 			   (status & ACPI_EC_FLAG_IBF) == 0) {
688 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
689 			wakeup = true;
690 		}
691 		goto out;
692 	} else {
693 		if (EC_FLAGS_QUERY_HANDSHAKE &&
694 		    !(status & ACPI_EC_FLAG_SCI) &&
695 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
696 			ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
697 			t->rdata[t->ri++] = 0x00;
698 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
699 			ec_dbg_evt("Command(%s) completed by software",
700 				   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
701 			wakeup = true;
702 		} else if ((status & ACPI_EC_FLAG_IBF) == 0) {
703 			acpi_ec_write_cmd(ec, t->command);
704 			ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
705 		} else
706 			goto err;
707 		goto out;
708 	}
709 err:
710 	/*
711 	 * If SCI bit is set, then don't think it's a false IRQ
712 	 * otherwise will take a not handled IRQ as a false one.
713 	 */
714 	if (!(status & ACPI_EC_FLAG_SCI)) {
715 		if (in_interrupt() && t) {
716 			if (t->irq_count < ec_storm_threshold)
717 				++t->irq_count;
718 			/* Allow triggering on 0 threshold */
719 			if (t->irq_count == ec_storm_threshold)
720 				acpi_ec_mask_gpe(ec);
721 		}
722 	}
723 out:
724 	if (status & ACPI_EC_FLAG_SCI)
725 		acpi_ec_submit_query(ec);
726 	if (wakeup && in_interrupt())
727 		wake_up(&ec->wait);
728 }
729 
730 static void start_transaction(struct acpi_ec *ec)
731 {
732 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
733 	ec->curr->flags = 0;
734 }
735 
736 static int ec_guard(struct acpi_ec *ec)
737 {
738 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
739 	unsigned long timeout = ec->timestamp + guard;
740 
741 	/* Ensure guarding period before polling EC status */
742 	do {
743 		if (ec->busy_polling) {
744 			/* Perform busy polling */
745 			if (ec_transaction_completed(ec))
746 				return 0;
747 			udelay(jiffies_to_usecs(guard));
748 		} else {
749 			/*
750 			 * Perform wait polling
751 			 * 1. Wait the transaction to be completed by the
752 			 *    GPE handler after the transaction enters
753 			 *    ACPI_EC_COMMAND_POLL state.
754 			 * 2. A special guarding logic is also required
755 			 *    for event clearing mode "event" before the
756 			 *    transaction enters ACPI_EC_COMMAND_POLL
757 			 *    state.
758 			 */
759 			if (!ec_transaction_polled(ec) &&
760 			    !acpi_ec_guard_event(ec))
761 				break;
762 			if (wait_event_timeout(ec->wait,
763 					       ec_transaction_completed(ec),
764 					       guard))
765 				return 0;
766 		}
767 	} while (time_before(jiffies, timeout));
768 	return -ETIME;
769 }
770 
771 static int ec_poll(struct acpi_ec *ec)
772 {
773 	unsigned long flags;
774 	int repeat = 5; /* number of command restarts */
775 
776 	while (repeat--) {
777 		unsigned long delay = jiffies +
778 			msecs_to_jiffies(ec_delay);
779 		do {
780 			if (!ec_guard(ec))
781 				return 0;
782 			spin_lock_irqsave(&ec->lock, flags);
783 			advance_transaction(ec);
784 			spin_unlock_irqrestore(&ec->lock, flags);
785 		} while (time_before(jiffies, delay));
786 		pr_debug("controller reset, restart transaction\n");
787 		spin_lock_irqsave(&ec->lock, flags);
788 		start_transaction(ec);
789 		spin_unlock_irqrestore(&ec->lock, flags);
790 	}
791 	return -ETIME;
792 }
793 
794 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
795 					struct transaction *t)
796 {
797 	unsigned long tmp;
798 	int ret = 0;
799 
800 	/* start transaction */
801 	spin_lock_irqsave(&ec->lock, tmp);
802 	/* Enable GPE for command processing (IBF=0/OBF=1) */
803 	if (!acpi_ec_submit_flushable_request(ec)) {
804 		ret = -EINVAL;
805 		goto unlock;
806 	}
807 	ec_dbg_ref(ec, "Increase command");
808 	/* following two actions should be kept atomic */
809 	ec->curr = t;
810 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
811 	start_transaction(ec);
812 	spin_unlock_irqrestore(&ec->lock, tmp);
813 
814 	ret = ec_poll(ec);
815 
816 	spin_lock_irqsave(&ec->lock, tmp);
817 	if (t->irq_count == ec_storm_threshold)
818 		acpi_ec_unmask_gpe(ec);
819 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
820 	ec->curr = NULL;
821 	/* Disable GPE for command processing (IBF=0/OBF=1) */
822 	acpi_ec_complete_request(ec);
823 	ec_dbg_ref(ec, "Decrease command");
824 unlock:
825 	spin_unlock_irqrestore(&ec->lock, tmp);
826 	return ret;
827 }
828 
829 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
830 {
831 	int status;
832 	u32 glk;
833 
834 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
835 		return -EINVAL;
836 	if (t->rdata)
837 		memset(t->rdata, 0, t->rlen);
838 
839 	mutex_lock(&ec->mutex);
840 	if (ec->global_lock) {
841 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
842 		if (ACPI_FAILURE(status)) {
843 			status = -ENODEV;
844 			goto unlock;
845 		}
846 	}
847 
848 	status = acpi_ec_transaction_unlocked(ec, t);
849 
850 	if (ec->global_lock)
851 		acpi_release_global_lock(glk);
852 unlock:
853 	mutex_unlock(&ec->mutex);
854 	return status;
855 }
856 
857 static int acpi_ec_burst_enable(struct acpi_ec *ec)
858 {
859 	u8 d;
860 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
861 				.wdata = NULL, .rdata = &d,
862 				.wlen = 0, .rlen = 1};
863 
864 	return acpi_ec_transaction(ec, &t);
865 }
866 
867 static int acpi_ec_burst_disable(struct acpi_ec *ec)
868 {
869 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
870 				.wdata = NULL, .rdata = NULL,
871 				.wlen = 0, .rlen = 0};
872 
873 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
874 				acpi_ec_transaction(ec, &t) : 0;
875 }
876 
877 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
878 {
879 	int result;
880 	u8 d;
881 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
882 				.wdata = &address, .rdata = &d,
883 				.wlen = 1, .rlen = 1};
884 
885 	result = acpi_ec_transaction(ec, &t);
886 	*data = d;
887 	return result;
888 }
889 
890 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
891 {
892 	u8 wdata[2] = { address, data };
893 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
894 				.wdata = wdata, .rdata = NULL,
895 				.wlen = 2, .rlen = 0};
896 
897 	return acpi_ec_transaction(ec, &t);
898 }
899 
900 int ec_read(u8 addr, u8 *val)
901 {
902 	int err;
903 	u8 temp_data;
904 
905 	if (!first_ec)
906 		return -ENODEV;
907 
908 	err = acpi_ec_read(first_ec, addr, &temp_data);
909 
910 	if (!err) {
911 		*val = temp_data;
912 		return 0;
913 	}
914 	return err;
915 }
916 EXPORT_SYMBOL(ec_read);
917 
918 int ec_write(u8 addr, u8 val)
919 {
920 	int err;
921 
922 	if (!first_ec)
923 		return -ENODEV;
924 
925 	err = acpi_ec_write(first_ec, addr, val);
926 
927 	return err;
928 }
929 EXPORT_SYMBOL(ec_write);
930 
931 int ec_transaction(u8 command,
932 		   const u8 *wdata, unsigned wdata_len,
933 		   u8 *rdata, unsigned rdata_len)
934 {
935 	struct transaction t = {.command = command,
936 				.wdata = wdata, .rdata = rdata,
937 				.wlen = wdata_len, .rlen = rdata_len};
938 
939 	if (!first_ec)
940 		return -ENODEV;
941 
942 	return acpi_ec_transaction(first_ec, &t);
943 }
944 EXPORT_SYMBOL(ec_transaction);
945 
946 /* Get the handle to the EC device */
947 acpi_handle ec_get_handle(void)
948 {
949 	if (!first_ec)
950 		return NULL;
951 	return first_ec->handle;
952 }
953 EXPORT_SYMBOL(ec_get_handle);
954 
955 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
956 {
957 	unsigned long flags;
958 
959 	spin_lock_irqsave(&ec->lock, flags);
960 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
961 		ec_dbg_drv("Starting EC");
962 		/* Enable GPE for event processing (SCI_EVT=1) */
963 		if (!resuming) {
964 			acpi_ec_submit_request(ec);
965 			ec_dbg_ref(ec, "Increase driver");
966 		}
967 		ec_log_drv("EC started");
968 	}
969 	spin_unlock_irqrestore(&ec->lock, flags);
970 }
971 
972 static bool acpi_ec_stopped(struct acpi_ec *ec)
973 {
974 	unsigned long flags;
975 	bool flushed;
976 
977 	spin_lock_irqsave(&ec->lock, flags);
978 	flushed = acpi_ec_flushed(ec);
979 	spin_unlock_irqrestore(&ec->lock, flags);
980 	return flushed;
981 }
982 
983 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
984 {
985 	unsigned long flags;
986 
987 	spin_lock_irqsave(&ec->lock, flags);
988 	if (acpi_ec_started(ec)) {
989 		ec_dbg_drv("Stopping EC");
990 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
991 		spin_unlock_irqrestore(&ec->lock, flags);
992 		wait_event(ec->wait, acpi_ec_stopped(ec));
993 		spin_lock_irqsave(&ec->lock, flags);
994 		/* Disable GPE for event processing (SCI_EVT=1) */
995 		if (!suspending) {
996 			acpi_ec_complete_request(ec);
997 			ec_dbg_ref(ec, "Decrease driver");
998 		} else if (!ec_freeze_events)
999 			__acpi_ec_disable_event(ec);
1000 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
1001 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1002 		ec_log_drv("EC stopped");
1003 	}
1004 	spin_unlock_irqrestore(&ec->lock, flags);
1005 }
1006 
1007 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1008 {
1009 	unsigned long flags;
1010 
1011 	spin_lock_irqsave(&ec->lock, flags);
1012 	ec->busy_polling = true;
1013 	ec->polling_guard = 0;
1014 	ec_log_drv("interrupt blocked");
1015 	spin_unlock_irqrestore(&ec->lock, flags);
1016 }
1017 
1018 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1019 {
1020 	unsigned long flags;
1021 
1022 	spin_lock_irqsave(&ec->lock, flags);
1023 	ec->busy_polling = ec_busy_polling;
1024 	ec->polling_guard = ec_polling_guard;
1025 	ec_log_drv("interrupt unblocked");
1026 	spin_unlock_irqrestore(&ec->lock, flags);
1027 }
1028 
1029 void acpi_ec_block_transactions(void)
1030 {
1031 	struct acpi_ec *ec = first_ec;
1032 
1033 	if (!ec)
1034 		return;
1035 
1036 	mutex_lock(&ec->mutex);
1037 	/* Prevent transactions from being carried out */
1038 	acpi_ec_stop(ec, true);
1039 	mutex_unlock(&ec->mutex);
1040 }
1041 
1042 void acpi_ec_unblock_transactions(void)
1043 {
1044 	/*
1045 	 * Allow transactions to happen again (this function is called from
1046 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1047 	 */
1048 	if (first_ec)
1049 		acpi_ec_start(first_ec, true);
1050 }
1051 
1052 /* --------------------------------------------------------------------------
1053                                 Event Management
1054    -------------------------------------------------------------------------- */
1055 static struct acpi_ec_query_handler *
1056 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
1057 {
1058 	if (handler)
1059 		kref_get(&handler->kref);
1060 	return handler;
1061 }
1062 
1063 static struct acpi_ec_query_handler *
1064 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1065 {
1066 	struct acpi_ec_query_handler *handler;
1067 	bool found = false;
1068 
1069 	mutex_lock(&ec->mutex);
1070 	list_for_each_entry(handler, &ec->list, node) {
1071 		if (value == handler->query_bit) {
1072 			found = true;
1073 			break;
1074 		}
1075 	}
1076 	mutex_unlock(&ec->mutex);
1077 	return found ? acpi_ec_get_query_handler(handler) : NULL;
1078 }
1079 
1080 static void acpi_ec_query_handler_release(struct kref *kref)
1081 {
1082 	struct acpi_ec_query_handler *handler =
1083 		container_of(kref, struct acpi_ec_query_handler, kref);
1084 
1085 	kfree(handler);
1086 }
1087 
1088 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1089 {
1090 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1091 }
1092 
1093 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1094 			      acpi_handle handle, acpi_ec_query_func func,
1095 			      void *data)
1096 {
1097 	struct acpi_ec_query_handler *handler =
1098 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1099 
1100 	if (!handler)
1101 		return -ENOMEM;
1102 
1103 	handler->query_bit = query_bit;
1104 	handler->handle = handle;
1105 	handler->func = func;
1106 	handler->data = data;
1107 	mutex_lock(&ec->mutex);
1108 	kref_init(&handler->kref);
1109 	list_add(&handler->node, &ec->list);
1110 	mutex_unlock(&ec->mutex);
1111 	return 0;
1112 }
1113 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1114 
1115 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1116 					  bool remove_all, u8 query_bit)
1117 {
1118 	struct acpi_ec_query_handler *handler, *tmp;
1119 	LIST_HEAD(free_list);
1120 
1121 	mutex_lock(&ec->mutex);
1122 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1123 		if (remove_all || query_bit == handler->query_bit) {
1124 			list_del_init(&handler->node);
1125 			list_add(&handler->node, &free_list);
1126 		}
1127 	}
1128 	mutex_unlock(&ec->mutex);
1129 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1130 		acpi_ec_put_query_handler(handler);
1131 }
1132 
1133 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1134 {
1135 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1136 }
1137 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1138 
1139 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1140 {
1141 	struct acpi_ec_query *q;
1142 	struct transaction *t;
1143 
1144 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1145 	if (!q)
1146 		return NULL;
1147 	INIT_WORK(&q->work, acpi_ec_event_processor);
1148 	t = &q->transaction;
1149 	t->command = ACPI_EC_COMMAND_QUERY;
1150 	t->rdata = pval;
1151 	t->rlen = 1;
1152 	return q;
1153 }
1154 
1155 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1156 {
1157 	if (q) {
1158 		if (q->handler)
1159 			acpi_ec_put_query_handler(q->handler);
1160 		kfree(q);
1161 	}
1162 }
1163 
1164 static void acpi_ec_event_processor(struct work_struct *work)
1165 {
1166 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1167 	struct acpi_ec_query_handler *handler = q->handler;
1168 
1169 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1170 	if (handler->func)
1171 		handler->func(handler->data);
1172 	else if (handler->handle)
1173 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1174 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1175 	acpi_ec_delete_query(q);
1176 }
1177 
1178 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1179 {
1180 	u8 value = 0;
1181 	int result;
1182 	struct acpi_ec_query *q;
1183 
1184 	q = acpi_ec_create_query(&value);
1185 	if (!q)
1186 		return -ENOMEM;
1187 
1188 	/*
1189 	 * Query the EC to find out which _Qxx method we need to evaluate.
1190 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1191 	 * bit to be cleared (and thus clearing the interrupt source).
1192 	 */
1193 	result = acpi_ec_transaction(ec, &q->transaction);
1194 	if (!value)
1195 		result = -ENODATA;
1196 	if (result)
1197 		goto err_exit;
1198 
1199 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1200 	if (!q->handler) {
1201 		result = -ENODATA;
1202 		goto err_exit;
1203 	}
1204 
1205 	/*
1206 	 * It is reported that _Qxx are evaluated in a parallel way on
1207 	 * Windows:
1208 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1209 	 *
1210 	 * Put this log entry before schedule_work() in order to make
1211 	 * it appearing before any other log entries occurred during the
1212 	 * work queue execution.
1213 	 */
1214 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1215 	if (!queue_work(ec_query_wq, &q->work)) {
1216 		ec_dbg_evt("Query(0x%02x) overlapped", value);
1217 		result = -EBUSY;
1218 	}
1219 
1220 err_exit:
1221 	if (result)
1222 		acpi_ec_delete_query(q);
1223 	if (data)
1224 		*data = value;
1225 	return result;
1226 }
1227 
1228 static void acpi_ec_check_event(struct acpi_ec *ec)
1229 {
1230 	unsigned long flags;
1231 
1232 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1233 		if (ec_guard(ec)) {
1234 			spin_lock_irqsave(&ec->lock, flags);
1235 			/*
1236 			 * Take care of the SCI_EVT unless no one else is
1237 			 * taking care of it.
1238 			 */
1239 			if (!ec->curr)
1240 				advance_transaction(ec);
1241 			spin_unlock_irqrestore(&ec->lock, flags);
1242 		}
1243 	}
1244 }
1245 
1246 static void acpi_ec_event_handler(struct work_struct *work)
1247 {
1248 	unsigned long flags;
1249 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1250 
1251 	ec_dbg_evt("Event started");
1252 
1253 	spin_lock_irqsave(&ec->lock, flags);
1254 	while (ec->nr_pending_queries) {
1255 		spin_unlock_irqrestore(&ec->lock, flags);
1256 		(void)acpi_ec_query(ec, NULL);
1257 		spin_lock_irqsave(&ec->lock, flags);
1258 		ec->nr_pending_queries--;
1259 		/*
1260 		 * Before exit, make sure that this work item can be
1261 		 * scheduled again. There might be QR_EC failures, leaving
1262 		 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1263 		 * item from being scheduled again.
1264 		 */
1265 		if (!ec->nr_pending_queries) {
1266 			if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1267 			    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1268 				acpi_ec_complete_query(ec);
1269 		}
1270 	}
1271 	spin_unlock_irqrestore(&ec->lock, flags);
1272 
1273 	ec_dbg_evt("Event stopped");
1274 
1275 	acpi_ec_check_event(ec);
1276 }
1277 
1278 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1279 	u32 gpe_number, void *data)
1280 {
1281 	unsigned long flags;
1282 	struct acpi_ec *ec = data;
1283 
1284 	spin_lock_irqsave(&ec->lock, flags);
1285 	advance_transaction(ec);
1286 	spin_unlock_irqrestore(&ec->lock, flags);
1287 	return ACPI_INTERRUPT_HANDLED;
1288 }
1289 
1290 /* --------------------------------------------------------------------------
1291  *                           Address Space Management
1292  * -------------------------------------------------------------------------- */
1293 
1294 static acpi_status
1295 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1296 		      u32 bits, u64 *value64,
1297 		      void *handler_context, void *region_context)
1298 {
1299 	struct acpi_ec *ec = handler_context;
1300 	int result = 0, i, bytes = bits / 8;
1301 	u8 *value = (u8 *)value64;
1302 
1303 	if ((address > 0xFF) || !value || !handler_context)
1304 		return AE_BAD_PARAMETER;
1305 
1306 	if (function != ACPI_READ && function != ACPI_WRITE)
1307 		return AE_BAD_PARAMETER;
1308 
1309 	if (ec->busy_polling || bits > 8)
1310 		acpi_ec_burst_enable(ec);
1311 
1312 	for (i = 0; i < bytes; ++i, ++address, ++value)
1313 		result = (function == ACPI_READ) ?
1314 			acpi_ec_read(ec, address, value) :
1315 			acpi_ec_write(ec, address, *value);
1316 
1317 	if (ec->busy_polling || bits > 8)
1318 		acpi_ec_burst_disable(ec);
1319 
1320 	switch (result) {
1321 	case -EINVAL:
1322 		return AE_BAD_PARAMETER;
1323 	case -ENODEV:
1324 		return AE_NOT_FOUND;
1325 	case -ETIME:
1326 		return AE_TIME;
1327 	default:
1328 		return AE_OK;
1329 	}
1330 }
1331 
1332 /* --------------------------------------------------------------------------
1333  *                             Driver Interface
1334  * -------------------------------------------------------------------------- */
1335 
1336 static acpi_status
1337 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1338 
1339 static void acpi_ec_free(struct acpi_ec *ec)
1340 {
1341 	if (first_ec == ec)
1342 		first_ec = NULL;
1343 	if (boot_ec == ec)
1344 		boot_ec = NULL;
1345 	kfree(ec);
1346 }
1347 
1348 static struct acpi_ec *acpi_ec_alloc(void)
1349 {
1350 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1351 
1352 	if (!ec)
1353 		return NULL;
1354 	mutex_init(&ec->mutex);
1355 	init_waitqueue_head(&ec->wait);
1356 	INIT_LIST_HEAD(&ec->list);
1357 	spin_lock_init(&ec->lock);
1358 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1359 	ec->timestamp = jiffies;
1360 	ec->busy_polling = true;
1361 	ec->polling_guard = 0;
1362 	return ec;
1363 }
1364 
1365 static acpi_status
1366 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1367 			       void *context, void **return_value)
1368 {
1369 	char node_name[5];
1370 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1371 	struct acpi_ec *ec = context;
1372 	int value = 0;
1373 	acpi_status status;
1374 
1375 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1376 
1377 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1378 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1379 	return AE_OK;
1380 }
1381 
1382 static acpi_status
1383 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1384 {
1385 	acpi_status status;
1386 	unsigned long long tmp = 0;
1387 	struct acpi_ec *ec = context;
1388 
1389 	/* clear addr values, ec_parse_io_ports depend on it */
1390 	ec->command_addr = ec->data_addr = 0;
1391 
1392 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1393 				     ec_parse_io_ports, ec);
1394 	if (ACPI_FAILURE(status))
1395 		return status;
1396 	if (ec->data_addr == 0 || ec->command_addr == 0)
1397 		return AE_OK;
1398 
1399 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1400 		/*
1401 		 * Always inherit the GPE number setting from the ECDT
1402 		 * EC.
1403 		 */
1404 		ec->gpe = boot_ec->gpe;
1405 	} else {
1406 		/* Get GPE bit assignment (EC events). */
1407 		/* TODO: Add support for _GPE returning a package */
1408 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1409 		if (ACPI_FAILURE(status))
1410 			return status;
1411 		ec->gpe = tmp;
1412 	}
1413 	/* Use the global lock for all EC transactions? */
1414 	tmp = 0;
1415 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1416 	ec->global_lock = tmp;
1417 	ec->handle = handle;
1418 	return AE_CTRL_TERMINATE;
1419 }
1420 
1421 /*
1422  * Note: This function returns an error code only when the address space
1423  *       handler is not installed, which means "not able to handle
1424  *       transactions".
1425  */
1426 static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1427 {
1428 	acpi_status status;
1429 
1430 	acpi_ec_start(ec, false);
1431 
1432 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1433 		acpi_ec_enter_noirq(ec);
1434 		status = acpi_install_address_space_handler(ec->handle,
1435 							    ACPI_ADR_SPACE_EC,
1436 							    &acpi_ec_space_handler,
1437 							    NULL, ec);
1438 		if (ACPI_FAILURE(status)) {
1439 			if (status == AE_NOT_FOUND) {
1440 				/*
1441 				 * Maybe OS fails in evaluating the _REG
1442 				 * object. The AE_NOT_FOUND error will be
1443 				 * ignored and OS * continue to initialize
1444 				 * EC.
1445 				 */
1446 				pr_err("Fail in evaluating the _REG object"
1447 					" of EC device. Broken bios is suspected.\n");
1448 			} else {
1449 				acpi_ec_stop(ec, false);
1450 				return -ENODEV;
1451 			}
1452 		}
1453 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1454 	}
1455 
1456 	if (!handle_events)
1457 		return 0;
1458 
1459 	if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1460 		/* Find and register all query methods */
1461 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1462 				    acpi_ec_register_query_methods,
1463 				    NULL, ec, NULL);
1464 		set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1465 	}
1466 	if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1467 		status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1468 					  ACPI_GPE_EDGE_TRIGGERED,
1469 					  &acpi_ec_gpe_handler, ec);
1470 		/* This is not fatal as we can poll EC events */
1471 		if (ACPI_SUCCESS(status)) {
1472 			set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1473 			acpi_ec_leave_noirq(ec);
1474 			if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1475 			    ec->reference_count >= 1)
1476 				acpi_ec_enable_gpe(ec, true);
1477 		}
1478 	}
1479 	/* EC is fully operational, allow queries */
1480 	acpi_ec_enable_event(ec);
1481 
1482 	return 0;
1483 }
1484 
1485 static void ec_remove_handlers(struct acpi_ec *ec)
1486 {
1487 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1488 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1489 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1490 			pr_err("failed to remove space handler\n");
1491 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1492 	}
1493 
1494 	/*
1495 	 * Stops handling the EC transactions after removing the operation
1496 	 * region handler. This is required because _REG(DISCONNECT)
1497 	 * invoked during the removal can result in new EC transactions.
1498 	 *
1499 	 * Flushes the EC requests and thus disables the GPE before
1500 	 * removing the GPE handler. This is required by the current ACPICA
1501 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1502 	 * it is indicated but there is no way to handle it. So the drivers
1503 	 * must disable the GPEs prior to removing the GPE handlers.
1504 	 */
1505 	acpi_ec_stop(ec, false);
1506 
1507 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1508 		if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1509 					&acpi_ec_gpe_handler)))
1510 			pr_err("failed to remove gpe handler\n");
1511 		clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1512 	}
1513 	if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1514 		acpi_ec_remove_query_handlers(ec, true, 0);
1515 		clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1516 	}
1517 }
1518 
1519 static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1520 {
1521 	int ret;
1522 
1523 	ret = ec_install_handlers(ec, handle_events);
1524 	if (ret)
1525 		return ret;
1526 
1527 	/* First EC capable of handling transactions */
1528 	if (!first_ec) {
1529 		first_ec = ec;
1530 		acpi_handle_info(first_ec->handle, "Used as first EC\n");
1531 	}
1532 
1533 	acpi_handle_info(ec->handle,
1534 			 "GPE=0x%x, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1535 			 ec->gpe, ec->command_addr, ec->data_addr);
1536 	return ret;
1537 }
1538 
1539 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1540 {
1541 	struct acpi_table_ecdt *ecdt_ptr;
1542 	acpi_status status;
1543 	acpi_handle handle;
1544 
1545 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1546 				(struct acpi_table_header **)&ecdt_ptr);
1547 	if (ACPI_FAILURE(status))
1548 		return false;
1549 
1550 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1551 	if (ACPI_FAILURE(status))
1552 		return false;
1553 
1554 	*phandle = handle;
1555 	return true;
1556 }
1557 
1558 static int acpi_ec_add(struct acpi_device *device)
1559 {
1560 	struct acpi_ec *ec = NULL;
1561 	bool dep_update = true;
1562 	acpi_status status;
1563 	int ret;
1564 
1565 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1566 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1567 
1568 	if (!strcmp(acpi_device_hid(device), ACPI_ECDT_HID)) {
1569 		boot_ec_is_ecdt = true;
1570 		ec = boot_ec;
1571 		dep_update = false;
1572 	} else {
1573 		ec = acpi_ec_alloc();
1574 		if (!ec)
1575 			return -ENOMEM;
1576 
1577 		status = ec_parse_device(device->handle, 0, ec, NULL);
1578 		if (status != AE_CTRL_TERMINATE) {
1579 			ret = -EINVAL;
1580 			goto err_alloc;
1581 		}
1582 
1583 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1584 		    ec->data_addr == boot_ec->data_addr) {
1585 			boot_ec_is_ecdt = false;
1586 			/*
1587 			 * Trust PNP0C09 namespace location rather than
1588 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1589 			 * because of ASUS quirks, so do not change
1590 			 * boot_ec->gpe to ec->gpe.
1591 			 */
1592 			boot_ec->handle = ec->handle;
1593 			acpi_handle_debug(ec->handle, "duplicated.\n");
1594 			acpi_ec_free(ec);
1595 			ec = boot_ec;
1596 		}
1597 	}
1598 
1599 	ret = acpi_ec_setup(ec, true);
1600 	if (ret)
1601 		goto err_query;
1602 
1603 	if (ec == boot_ec)
1604 		acpi_handle_info(boot_ec->handle,
1605 				 "Boot %s EC used to handle transactions and events\n",
1606 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1607 
1608 	device->driver_data = ec;
1609 
1610 	ret = !!request_region(ec->data_addr, 1, "EC data");
1611 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1612 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1613 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1614 
1615 	if (dep_update) {
1616 		/* Reprobe devices depending on the EC */
1617 		acpi_walk_dep_device_list(ec->handle);
1618 	}
1619 	acpi_handle_debug(ec->handle, "enumerated.\n");
1620 	return 0;
1621 
1622 err_query:
1623 	if (ec != boot_ec)
1624 		acpi_ec_remove_query_handlers(ec, true, 0);
1625 err_alloc:
1626 	if (ec != boot_ec)
1627 		acpi_ec_free(ec);
1628 	return ret;
1629 }
1630 
1631 static int acpi_ec_remove(struct acpi_device *device)
1632 {
1633 	struct acpi_ec *ec;
1634 
1635 	if (!device)
1636 		return -EINVAL;
1637 
1638 	ec = acpi_driver_data(device);
1639 	release_region(ec->data_addr, 1);
1640 	release_region(ec->command_addr, 1);
1641 	device->driver_data = NULL;
1642 	if (ec != boot_ec) {
1643 		ec_remove_handlers(ec);
1644 		acpi_ec_free(ec);
1645 	}
1646 	return 0;
1647 }
1648 
1649 static acpi_status
1650 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1651 {
1652 	struct acpi_ec *ec = context;
1653 
1654 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1655 		return AE_OK;
1656 
1657 	/*
1658 	 * The first address region returned is the data port, and
1659 	 * the second address region returned is the status/command
1660 	 * port.
1661 	 */
1662 	if (ec->data_addr == 0)
1663 		ec->data_addr = resource->data.io.minimum;
1664 	else if (ec->command_addr == 0)
1665 		ec->command_addr = resource->data.io.minimum;
1666 	else
1667 		return AE_CTRL_TERMINATE;
1668 
1669 	return AE_OK;
1670 }
1671 
1672 static const struct acpi_device_id ec_device_ids[] = {
1673 	{"PNP0C09", 0},
1674 	{ACPI_ECDT_HID, 0},
1675 	{"", 0},
1676 };
1677 
1678 /*
1679  * This function is not Windows-compatible as Windows never enumerates the
1680  * namespace EC before the main ACPI device enumeration process. It is
1681  * retained for historical reason and will be deprecated in the future.
1682  */
1683 void __init acpi_ec_dsdt_probe(void)
1684 {
1685 	struct acpi_ec *ec;
1686 	acpi_status status;
1687 	int ret;
1688 
1689 	/*
1690 	 * If a platform has ECDT, there is no need to proceed as the
1691 	 * following probe is not a part of the ACPI device enumeration,
1692 	 * executing _STA is not safe, and thus this probe may risk of
1693 	 * picking up an invalid EC device.
1694 	 */
1695 	if (boot_ec)
1696 		return;
1697 
1698 	ec = acpi_ec_alloc();
1699 	if (!ec)
1700 		return;
1701 
1702 	/*
1703 	 * At this point, the namespace is initialized, so start to find
1704 	 * the namespace objects.
1705 	 */
1706 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1707 	if (ACPI_FAILURE(status) || !ec->handle) {
1708 		acpi_ec_free(ec);
1709 		return;
1710 	}
1711 
1712 	/*
1713 	 * When the DSDT EC is available, always re-configure boot EC to
1714 	 * have _REG evaluated. _REG can only be evaluated after the
1715 	 * namespace initialization.
1716 	 * At this point, the GPE is not fully initialized, so do not to
1717 	 * handle the events.
1718 	 */
1719 	ret = acpi_ec_setup(ec, false);
1720 	if (ret) {
1721 		acpi_ec_free(ec);
1722 		return;
1723 	}
1724 
1725 	boot_ec = ec;
1726 
1727 	acpi_handle_info(ec->handle,
1728 			 "Boot DSDT EC used to handle transactions\n");
1729 }
1730 
1731 /*
1732  * If the DSDT EC is not functioning, we still need to prepare a fully
1733  * functioning ECDT EC first in order to handle the events.
1734  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1735  */
1736 static int __init acpi_ec_ecdt_start(void)
1737 {
1738 	acpi_handle handle;
1739 
1740 	if (!boot_ec)
1741 		return -ENODEV;
1742 	/* In case acpi_ec_ecdt_start() is called after acpi_ec_add() */
1743 	if (!boot_ec_is_ecdt)
1744 		return -ENODEV;
1745 
1746 	/*
1747 	 * At this point, the namespace and the GPE is initialized, so
1748 	 * start to find the namespace objects and handle the events.
1749 	 *
1750 	 * Note: ec->handle can be valid if this function is called after
1751 	 * acpi_ec_add(), hence the fast path.
1752 	 */
1753 	if (boot_ec->handle == ACPI_ROOT_OBJECT) {
1754 		if (!acpi_ec_ecdt_get_handle(&handle))
1755 			return -ENODEV;
1756 		boot_ec->handle = handle;
1757 	}
1758 
1759 	/* Register to ACPI bus with PM ops attached */
1760 	return acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1761 }
1762 
1763 #if 0
1764 /*
1765  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1766  * set, for which case, we complete the QR_EC without issuing it to the
1767  * firmware.
1768  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1769  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1770  */
1771 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1772 {
1773 	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1774 	EC_FLAGS_QUERY_HANDSHAKE = 1;
1775 	return 0;
1776 }
1777 #endif
1778 
1779 /*
1780  * On some hardware it is necessary to clear events accumulated by the EC during
1781  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1782  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1783  *
1784  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1785  *
1786  * Ideally, the EC should also be instructed NOT to accumulate events during
1787  * sleep (which Windows seems to do somehow), but the interface to control this
1788  * behaviour is not known at this time.
1789  *
1790  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1791  * however it is very likely that other Samsung models are affected.
1792  *
1793  * On systems which don't accumulate _Q events during sleep, this extra check
1794  * should be harmless.
1795  */
1796 static int ec_clear_on_resume(const struct dmi_system_id *id)
1797 {
1798 	pr_debug("Detected system needing EC poll on resume.\n");
1799 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1800 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1801 	return 0;
1802 }
1803 
1804 /*
1805  * Some ECDTs contain wrong register addresses.
1806  * MSI MS-171F
1807  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1808  */
1809 static int ec_correct_ecdt(const struct dmi_system_id *id)
1810 {
1811 	pr_debug("Detected system needing ECDT address correction.\n");
1812 	EC_FLAGS_CORRECT_ECDT = 1;
1813 	return 0;
1814 }
1815 
1816 /*
1817  * Some DSDTs contain wrong GPE setting.
1818  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1819  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1820  */
1821 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1822 {
1823 	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1824 	EC_FLAGS_IGNORE_DSDT_GPE = 1;
1825 	return 0;
1826 }
1827 
1828 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1829 	{
1830 	ec_correct_ecdt, "MSI MS-171F", {
1831 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1832 	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1833 	{
1834 	ec_honor_ecdt_gpe, "ASUS FX502VD", {
1835 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1836 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1837 	{
1838 	ec_honor_ecdt_gpe, "ASUS FX502VE", {
1839 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1840 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1841 	{
1842 	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1843 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1844 	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1845 	{
1846 	ec_honor_ecdt_gpe, "ASUS X550VXK", {
1847 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1848 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1849 	{
1850 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1851 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1852 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1853 	{
1854 	ec_clear_on_resume, "Samsung hardware", {
1855 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1856 	{},
1857 };
1858 
1859 void __init acpi_ec_ecdt_probe(void)
1860 {
1861 	struct acpi_table_ecdt *ecdt_ptr;
1862 	struct acpi_ec *ec;
1863 	acpi_status status;
1864 	int ret;
1865 
1866 	/* Generate a boot ec context. */
1867 	dmi_check_system(ec_dmi_table);
1868 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1869 				(struct acpi_table_header **)&ecdt_ptr);
1870 	if (ACPI_FAILURE(status))
1871 		return;
1872 
1873 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1874 		/*
1875 		 * Asus X50GL:
1876 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1877 		 */
1878 		return;
1879 	}
1880 
1881 	ec = acpi_ec_alloc();
1882 	if (!ec)
1883 		return;
1884 
1885 	if (EC_FLAGS_CORRECT_ECDT) {
1886 		ec->command_addr = ecdt_ptr->data.address;
1887 		ec->data_addr = ecdt_ptr->control.address;
1888 	} else {
1889 		ec->command_addr = ecdt_ptr->control.address;
1890 		ec->data_addr = ecdt_ptr->data.address;
1891 	}
1892 	ec->gpe = ecdt_ptr->gpe;
1893 	ec->handle = ACPI_ROOT_OBJECT;
1894 
1895 	/*
1896 	 * At this point, the namespace is not initialized, so do not find
1897 	 * the namespace objects, or handle the events.
1898 	 */
1899 	ret = acpi_ec_setup(ec, false);
1900 	if (ret) {
1901 		acpi_ec_free(ec);
1902 		return;
1903 	}
1904 
1905 	boot_ec = ec;
1906 	boot_ec_is_ecdt = true;
1907 
1908 	pr_info("Boot ECDT EC used to handle transactions\n");
1909 }
1910 
1911 #ifdef CONFIG_PM_SLEEP
1912 static int acpi_ec_suspend(struct device *dev)
1913 {
1914 	struct acpi_ec *ec =
1915 		acpi_driver_data(to_acpi_device(dev));
1916 
1917 	if (!pm_suspend_no_platform() && ec_freeze_events)
1918 		acpi_ec_disable_event(ec);
1919 	return 0;
1920 }
1921 
1922 static int acpi_ec_suspend_noirq(struct device *dev)
1923 {
1924 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1925 
1926 	/*
1927 	 * The SCI handler doesn't run at this point, so the GPE can be
1928 	 * masked at the low level without side effects.
1929 	 */
1930 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1931 	    ec->reference_count >= 1)
1932 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1933 
1934 	acpi_ec_enter_noirq(ec);
1935 
1936 	return 0;
1937 }
1938 
1939 static int acpi_ec_resume_noirq(struct device *dev)
1940 {
1941 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1942 
1943 	acpi_ec_leave_noirq(ec);
1944 
1945 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1946 	    ec->reference_count >= 1)
1947 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1948 
1949 	return 0;
1950 }
1951 
1952 static int acpi_ec_resume(struct device *dev)
1953 {
1954 	struct acpi_ec *ec =
1955 		acpi_driver_data(to_acpi_device(dev));
1956 
1957 	acpi_ec_enable_event(ec);
1958 	return 0;
1959 }
1960 
1961 void acpi_ec_mark_gpe_for_wake(void)
1962 {
1963 	if (first_ec && !ec_no_wakeup)
1964 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1965 }
1966 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
1967 
1968 void acpi_ec_set_gpe_wake_mask(u8 action)
1969 {
1970 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
1971 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1972 }
1973 
1974 bool acpi_ec_dispatch_gpe(void)
1975 {
1976 	u32 ret;
1977 
1978 	if (!first_ec)
1979 		return false;
1980 
1981 	ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
1982 	if (ret == ACPI_INTERRUPT_HANDLED) {
1983 		pm_pr_dbg("EC GPE dispatched\n");
1984 		return true;
1985 	}
1986 	return false;
1987 }
1988 #endif /* CONFIG_PM_SLEEP */
1989 
1990 static const struct dev_pm_ops acpi_ec_pm = {
1991 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
1992 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1993 };
1994 
1995 static int param_set_event_clearing(const char *val,
1996 				    const struct kernel_param *kp)
1997 {
1998 	int result = 0;
1999 
2000 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2001 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2002 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2003 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2004 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2005 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2006 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2007 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2008 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2009 	} else
2010 		result = -EINVAL;
2011 	return result;
2012 }
2013 
2014 static int param_get_event_clearing(char *buffer,
2015 				    const struct kernel_param *kp)
2016 {
2017 	switch (ec_event_clearing) {
2018 	case ACPI_EC_EVT_TIMING_STATUS:
2019 		return sprintf(buffer, "status");
2020 	case ACPI_EC_EVT_TIMING_QUERY:
2021 		return sprintf(buffer, "query");
2022 	case ACPI_EC_EVT_TIMING_EVENT:
2023 		return sprintf(buffer, "event");
2024 	default:
2025 		return sprintf(buffer, "invalid");
2026 	}
2027 	return 0;
2028 }
2029 
2030 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2031 		  NULL, 0644);
2032 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2033 
2034 static struct acpi_driver acpi_ec_driver = {
2035 	.name = "ec",
2036 	.class = ACPI_EC_CLASS,
2037 	.ids = ec_device_ids,
2038 	.ops = {
2039 		.add = acpi_ec_add,
2040 		.remove = acpi_ec_remove,
2041 		},
2042 	.drv.pm = &acpi_ec_pm,
2043 };
2044 
2045 static inline int acpi_ec_query_init(void)
2046 {
2047 	if (!ec_query_wq) {
2048 		ec_query_wq = alloc_workqueue("kec_query", 0,
2049 					      ec_max_queries);
2050 		if (!ec_query_wq)
2051 			return -ENODEV;
2052 	}
2053 	return 0;
2054 }
2055 
2056 static inline void acpi_ec_query_exit(void)
2057 {
2058 	if (ec_query_wq) {
2059 		destroy_workqueue(ec_query_wq);
2060 		ec_query_wq = NULL;
2061 	}
2062 }
2063 
2064 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2065 	{
2066 		.ident = "Thinkpad X1 Carbon 6th",
2067 		.matches = {
2068 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2069 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2070 		},
2071 	},
2072 	{
2073 		.ident = "ThinkPad X1 Carbon 6th",
2074 		.matches = {
2075 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2076 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2077 		},
2078 	},
2079 	{
2080 		.ident = "ThinkPad X1 Yoga 3rd",
2081 		.matches = {
2082 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2083 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2084 		},
2085 	},
2086 	{ },
2087 };
2088 
2089 int __init acpi_ec_init(void)
2090 {
2091 	int result;
2092 	int ecdt_fail, dsdt_fail;
2093 
2094 	/* register workqueue for _Qxx evaluations */
2095 	result = acpi_ec_query_init();
2096 	if (result)
2097 		return result;
2098 
2099 	/*
2100 	 * Disable EC wakeup on following systems to prevent periodic
2101 	 * wakeup from EC GPE.
2102 	 */
2103 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2104 		ec_no_wakeup = true;
2105 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2106 	}
2107 
2108 	/* Drivers must be started after acpi_ec_query_init() */
2109 	dsdt_fail = acpi_bus_register_driver(&acpi_ec_driver);
2110 	/*
2111 	 * Register ECDT to ACPI bus only when PNP0C09 probe fails. This is
2112 	 * useful for platforms (confirmed on ASUS X550ZE) with valid ECDT
2113 	 * settings but invalid DSDT settings.
2114 	 * https://bugzilla.kernel.org/show_bug.cgi?id=196847
2115 	 */
2116 	ecdt_fail = acpi_ec_ecdt_start();
2117 	return ecdt_fail && dsdt_fail ? -ENODEV : 0;
2118 }
2119 
2120 /* EC driver currently not unloadable */
2121 #if 0
2122 static void __exit acpi_ec_exit(void)
2123 {
2124 
2125 	acpi_bus_unregister_driver(&acpi_ec_driver);
2126 	acpi_ec_query_exit();
2127 }
2128 #endif	/* 0 */
2129