xref: /openbmc/linux/drivers/acpi/ec.c (revision 022dacdd)
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_EVENT_HANDLER_INSTALLED,	/* Event handler installed */
99 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
100 	EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
101 	EC_FLAGS_STARTED,		/* Driver is started */
102 	EC_FLAGS_STOPPED,		/* Driver is stopped */
103 	EC_FLAGS_EVENTS_MASKED,		/* Events 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_wq;
183 static struct workqueue_struct *ec_query_wq;
184 
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_EVENT_HANDLER_INSTALLED, &ec->flags) &&
401 	    ec->gpe >= 0 && 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_EVENT_HANDLER_INSTALLED, &ec->flags) &&
411 	    ec->gpe >= 0 && 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_events(struct acpi_ec *ec)
419 {
420 	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
421 		if (ec->gpe >= 0)
422 			acpi_ec_disable_gpe(ec, false);
423 		else
424 			disable_irq_nosync(ec->irq);
425 
426 		ec_dbg_drv("Polling enabled");
427 		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
428 	}
429 }
430 
431 static void acpi_ec_unmask_events(struct acpi_ec *ec)
432 {
433 	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
434 		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
435 		if (ec->gpe >= 0)
436 			acpi_ec_enable_gpe(ec, false);
437 		else
438 			enable_irq(ec->irq);
439 
440 		ec_dbg_drv("Polling disabled");
441 	}
442 }
443 
444 /*
445  * acpi_ec_submit_flushable_request() - Increase the reference count unless
446  *                                      the flush operation is not in
447  *                                      progress
448  * @ec: the EC device
449  *
450  * This function must be used before taking a new action that should hold
451  * the reference count.  If this function returns false, then the action
452  * must be discarded or it will prevent the flush operation from being
453  * completed.
454  */
455 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
456 {
457 	if (!acpi_ec_started(ec))
458 		return false;
459 	acpi_ec_submit_request(ec);
460 	return true;
461 }
462 
463 static void acpi_ec_submit_query(struct acpi_ec *ec)
464 {
465 	acpi_ec_mask_events(ec);
466 	if (!acpi_ec_event_enabled(ec))
467 		return;
468 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
469 		ec_dbg_evt("Command(%s) submitted/blocked",
470 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
471 		ec->nr_pending_queries++;
472 		queue_work(ec_wq, &ec->work);
473 	}
474 }
475 
476 static void acpi_ec_complete_query(struct acpi_ec *ec)
477 {
478 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
479 		ec_dbg_evt("Command(%s) unblocked",
480 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
481 	acpi_ec_unmask_events(ec);
482 }
483 
484 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
485 {
486 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
487 		ec_log_drv("event unblocked");
488 	/*
489 	 * Unconditionally invoke this once after enabling the event
490 	 * handling mechanism to detect the pending events.
491 	 */
492 	advance_transaction(ec);
493 }
494 
495 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
496 {
497 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
498 		ec_log_drv("event blocked");
499 }
500 
501 /*
502  * Process _Q events that might have accumulated in the EC.
503  * Run with locked ec mutex.
504  */
505 static void acpi_ec_clear(struct acpi_ec *ec)
506 {
507 	int i, status;
508 	u8 value = 0;
509 
510 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
511 		status = acpi_ec_query(ec, &value);
512 		if (status || !value)
513 			break;
514 	}
515 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
516 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
517 	else
518 		pr_info("%d stale EC events cleared\n", i);
519 }
520 
521 static void acpi_ec_enable_event(struct acpi_ec *ec)
522 {
523 	unsigned long flags;
524 
525 	spin_lock_irqsave(&ec->lock, flags);
526 	if (acpi_ec_started(ec))
527 		__acpi_ec_enable_event(ec);
528 	spin_unlock_irqrestore(&ec->lock, flags);
529 
530 	/* Drain additional events if hardware requires that */
531 	if (EC_FLAGS_CLEAR_ON_RESUME)
532 		acpi_ec_clear(ec);
533 }
534 
535 #ifdef CONFIG_PM_SLEEP
536 static void __acpi_ec_flush_work(void)
537 {
538 	drain_workqueue(ec_wq); /* flush ec->work */
539 	flush_workqueue(ec_query_wq); /* flush queries */
540 }
541 
542 static void acpi_ec_disable_event(struct acpi_ec *ec)
543 {
544 	unsigned long flags;
545 
546 	spin_lock_irqsave(&ec->lock, flags);
547 	__acpi_ec_disable_event(ec);
548 	spin_unlock_irqrestore(&ec->lock, flags);
549 
550 	/*
551 	 * When ec_freeze_events is true, we need to flush events in
552 	 * the proper position before entering the noirq stage.
553 	 */
554 	__acpi_ec_flush_work();
555 }
556 
557 void acpi_ec_flush_work(void)
558 {
559 	/* Without ec_wq there is nothing to flush. */
560 	if (!ec_wq)
561 		return;
562 
563 	__acpi_ec_flush_work();
564 }
565 #endif /* CONFIG_PM_SLEEP */
566 
567 static bool acpi_ec_guard_event(struct acpi_ec *ec)
568 {
569 	bool guarded = true;
570 	unsigned long flags;
571 
572 	spin_lock_irqsave(&ec->lock, flags);
573 	/*
574 	 * If firmware SCI_EVT clearing timing is "event", we actually
575 	 * don't know when the SCI_EVT will be cleared by firmware after
576 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
577 	 * acceptable period.
578 	 *
579 	 * The guarding period begins when EC_FLAGS_QUERY_PENDING is
580 	 * flagged, which means SCI_EVT check has just been performed.
581 	 * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
582 	 * guarding should have already been performed (via
583 	 * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
584 	 * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
585 	 * ACPI_EC_COMMAND_POLL state immediately.
586 	 */
587 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
588 	    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
589 	    !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
590 	    (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
591 		guarded = false;
592 	spin_unlock_irqrestore(&ec->lock, flags);
593 	return guarded;
594 }
595 
596 static int ec_transaction_polled(struct acpi_ec *ec)
597 {
598 	unsigned long flags;
599 	int ret = 0;
600 
601 	spin_lock_irqsave(&ec->lock, flags);
602 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
603 		ret = 1;
604 	spin_unlock_irqrestore(&ec->lock, flags);
605 	return ret;
606 }
607 
608 static int ec_transaction_completed(struct acpi_ec *ec)
609 {
610 	unsigned long flags;
611 	int ret = 0;
612 
613 	spin_lock_irqsave(&ec->lock, flags);
614 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
615 		ret = 1;
616 	spin_unlock_irqrestore(&ec->lock, flags);
617 	return ret;
618 }
619 
620 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
621 {
622 	ec->curr->flags |= flag;
623 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
624 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
625 		    flag == ACPI_EC_COMMAND_POLL)
626 			acpi_ec_complete_query(ec);
627 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
628 		    flag == ACPI_EC_COMMAND_COMPLETE)
629 			acpi_ec_complete_query(ec);
630 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
631 		    flag == ACPI_EC_COMMAND_COMPLETE)
632 			set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
633 	}
634 }
635 
636 static void advance_transaction(struct acpi_ec *ec)
637 {
638 	struct transaction *t;
639 	u8 status;
640 	bool wakeup = false;
641 
642 	ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
643 		   smp_processor_id());
644 	/*
645 	 * By always clearing STS before handling all indications, we can
646 	 * ensure a hardware STS 0->1 change after this clearing can always
647 	 * trigger a GPE interrupt.
648 	 */
649 	if (ec->gpe >= 0)
650 		acpi_ec_clear_gpe(ec);
651 
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 if (!(status & ACPI_EC_FLAG_IBF)) {
693 		acpi_ec_write_cmd(ec, t->command);
694 		ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
695 		goto out;
696 	}
697 err:
698 	/*
699 	 * If SCI bit is set, then don't think it's a false IRQ
700 	 * otherwise will take a not handled IRQ as a false one.
701 	 */
702 	if (!(status & ACPI_EC_FLAG_SCI)) {
703 		if (in_interrupt() && t) {
704 			if (t->irq_count < ec_storm_threshold)
705 				++t->irq_count;
706 			/* Allow triggering on 0 threshold */
707 			if (t->irq_count == ec_storm_threshold)
708 				acpi_ec_mask_events(ec);
709 		}
710 	}
711 out:
712 	if (status & ACPI_EC_FLAG_SCI)
713 		acpi_ec_submit_query(ec);
714 	if (wakeup && in_interrupt())
715 		wake_up(&ec->wait);
716 }
717 
718 static void start_transaction(struct acpi_ec *ec)
719 {
720 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
721 	ec->curr->flags = 0;
722 }
723 
724 static int ec_guard(struct acpi_ec *ec)
725 {
726 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
727 	unsigned long timeout = ec->timestamp + guard;
728 
729 	/* Ensure guarding period before polling EC status */
730 	do {
731 		if (ec->busy_polling) {
732 			/* Perform busy polling */
733 			if (ec_transaction_completed(ec))
734 				return 0;
735 			udelay(jiffies_to_usecs(guard));
736 		} else {
737 			/*
738 			 * Perform wait polling
739 			 * 1. Wait the transaction to be completed by the
740 			 *    GPE handler after the transaction enters
741 			 *    ACPI_EC_COMMAND_POLL state.
742 			 * 2. A special guarding logic is also required
743 			 *    for event clearing mode "event" before the
744 			 *    transaction enters ACPI_EC_COMMAND_POLL
745 			 *    state.
746 			 */
747 			if (!ec_transaction_polled(ec) &&
748 			    !acpi_ec_guard_event(ec))
749 				break;
750 			if (wait_event_timeout(ec->wait,
751 					       ec_transaction_completed(ec),
752 					       guard))
753 				return 0;
754 		}
755 	} while (time_before(jiffies, timeout));
756 	return -ETIME;
757 }
758 
759 static int ec_poll(struct acpi_ec *ec)
760 {
761 	unsigned long flags;
762 	int repeat = 5; /* number of command restarts */
763 
764 	while (repeat--) {
765 		unsigned long delay = jiffies +
766 			msecs_to_jiffies(ec_delay);
767 		do {
768 			if (!ec_guard(ec))
769 				return 0;
770 			spin_lock_irqsave(&ec->lock, flags);
771 			advance_transaction(ec);
772 			spin_unlock_irqrestore(&ec->lock, flags);
773 		} while (time_before(jiffies, delay));
774 		pr_debug("controller reset, restart transaction\n");
775 		spin_lock_irqsave(&ec->lock, flags);
776 		start_transaction(ec);
777 		spin_unlock_irqrestore(&ec->lock, flags);
778 	}
779 	return -ETIME;
780 }
781 
782 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
783 					struct transaction *t)
784 {
785 	unsigned long tmp;
786 	int ret = 0;
787 
788 	/* start transaction */
789 	spin_lock_irqsave(&ec->lock, tmp);
790 	/* Enable GPE for command processing (IBF=0/OBF=1) */
791 	if (!acpi_ec_submit_flushable_request(ec)) {
792 		ret = -EINVAL;
793 		goto unlock;
794 	}
795 	ec_dbg_ref(ec, "Increase command");
796 	/* following two actions should be kept atomic */
797 	ec->curr = t;
798 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
799 	start_transaction(ec);
800 	spin_unlock_irqrestore(&ec->lock, tmp);
801 
802 	ret = ec_poll(ec);
803 
804 	spin_lock_irqsave(&ec->lock, tmp);
805 	if (t->irq_count == ec_storm_threshold)
806 		acpi_ec_unmask_events(ec);
807 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
808 	ec->curr = NULL;
809 	/* Disable GPE for command processing (IBF=0/OBF=1) */
810 	acpi_ec_complete_request(ec);
811 	ec_dbg_ref(ec, "Decrease command");
812 unlock:
813 	spin_unlock_irqrestore(&ec->lock, tmp);
814 	return ret;
815 }
816 
817 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
818 {
819 	int status;
820 	u32 glk;
821 
822 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
823 		return -EINVAL;
824 	if (t->rdata)
825 		memset(t->rdata, 0, t->rlen);
826 
827 	mutex_lock(&ec->mutex);
828 	if (ec->global_lock) {
829 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
830 		if (ACPI_FAILURE(status)) {
831 			status = -ENODEV;
832 			goto unlock;
833 		}
834 	}
835 
836 	status = acpi_ec_transaction_unlocked(ec, t);
837 
838 	if (ec->global_lock)
839 		acpi_release_global_lock(glk);
840 unlock:
841 	mutex_unlock(&ec->mutex);
842 	return status;
843 }
844 
845 static int acpi_ec_burst_enable(struct acpi_ec *ec)
846 {
847 	u8 d;
848 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
849 				.wdata = NULL, .rdata = &d,
850 				.wlen = 0, .rlen = 1};
851 
852 	return acpi_ec_transaction(ec, &t);
853 }
854 
855 static int acpi_ec_burst_disable(struct acpi_ec *ec)
856 {
857 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
858 				.wdata = NULL, .rdata = NULL,
859 				.wlen = 0, .rlen = 0};
860 
861 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
862 				acpi_ec_transaction(ec, &t) : 0;
863 }
864 
865 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
866 {
867 	int result;
868 	u8 d;
869 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
870 				.wdata = &address, .rdata = &d,
871 				.wlen = 1, .rlen = 1};
872 
873 	result = acpi_ec_transaction(ec, &t);
874 	*data = d;
875 	return result;
876 }
877 
878 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
879 {
880 	u8 wdata[2] = { address, data };
881 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
882 				.wdata = wdata, .rdata = NULL,
883 				.wlen = 2, .rlen = 0};
884 
885 	return acpi_ec_transaction(ec, &t);
886 }
887 
888 int ec_read(u8 addr, u8 *val)
889 {
890 	int err;
891 	u8 temp_data;
892 
893 	if (!first_ec)
894 		return -ENODEV;
895 
896 	err = acpi_ec_read(first_ec, addr, &temp_data);
897 
898 	if (!err) {
899 		*val = temp_data;
900 		return 0;
901 	}
902 	return err;
903 }
904 EXPORT_SYMBOL(ec_read);
905 
906 int ec_write(u8 addr, u8 val)
907 {
908 	int err;
909 
910 	if (!first_ec)
911 		return -ENODEV;
912 
913 	err = acpi_ec_write(first_ec, addr, val);
914 
915 	return err;
916 }
917 EXPORT_SYMBOL(ec_write);
918 
919 int ec_transaction(u8 command,
920 		   const u8 *wdata, unsigned wdata_len,
921 		   u8 *rdata, unsigned rdata_len)
922 {
923 	struct transaction t = {.command = command,
924 				.wdata = wdata, .rdata = rdata,
925 				.wlen = wdata_len, .rlen = rdata_len};
926 
927 	if (!first_ec)
928 		return -ENODEV;
929 
930 	return acpi_ec_transaction(first_ec, &t);
931 }
932 EXPORT_SYMBOL(ec_transaction);
933 
934 /* Get the handle to the EC device */
935 acpi_handle ec_get_handle(void)
936 {
937 	if (!first_ec)
938 		return NULL;
939 	return first_ec->handle;
940 }
941 EXPORT_SYMBOL(ec_get_handle);
942 
943 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
944 {
945 	unsigned long flags;
946 
947 	spin_lock_irqsave(&ec->lock, flags);
948 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
949 		ec_dbg_drv("Starting EC");
950 		/* Enable GPE for event processing (SCI_EVT=1) */
951 		if (!resuming) {
952 			acpi_ec_submit_request(ec);
953 			ec_dbg_ref(ec, "Increase driver");
954 		}
955 		ec_log_drv("EC started");
956 	}
957 	spin_unlock_irqrestore(&ec->lock, flags);
958 }
959 
960 static bool acpi_ec_stopped(struct acpi_ec *ec)
961 {
962 	unsigned long flags;
963 	bool flushed;
964 
965 	spin_lock_irqsave(&ec->lock, flags);
966 	flushed = acpi_ec_flushed(ec);
967 	spin_unlock_irqrestore(&ec->lock, flags);
968 	return flushed;
969 }
970 
971 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
972 {
973 	unsigned long flags;
974 
975 	spin_lock_irqsave(&ec->lock, flags);
976 	if (acpi_ec_started(ec)) {
977 		ec_dbg_drv("Stopping EC");
978 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
979 		spin_unlock_irqrestore(&ec->lock, flags);
980 		wait_event(ec->wait, acpi_ec_stopped(ec));
981 		spin_lock_irqsave(&ec->lock, flags);
982 		/* Disable GPE for event processing (SCI_EVT=1) */
983 		if (!suspending) {
984 			acpi_ec_complete_request(ec);
985 			ec_dbg_ref(ec, "Decrease driver");
986 		} else if (!ec_freeze_events)
987 			__acpi_ec_disable_event(ec);
988 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
989 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
990 		ec_log_drv("EC stopped");
991 	}
992 	spin_unlock_irqrestore(&ec->lock, flags);
993 }
994 
995 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
996 {
997 	unsigned long flags;
998 
999 	spin_lock_irqsave(&ec->lock, flags);
1000 	ec->busy_polling = true;
1001 	ec->polling_guard = 0;
1002 	ec_log_drv("interrupt blocked");
1003 	spin_unlock_irqrestore(&ec->lock, flags);
1004 }
1005 
1006 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1007 {
1008 	unsigned long flags;
1009 
1010 	spin_lock_irqsave(&ec->lock, flags);
1011 	ec->busy_polling = ec_busy_polling;
1012 	ec->polling_guard = ec_polling_guard;
1013 	ec_log_drv("interrupt unblocked");
1014 	spin_unlock_irqrestore(&ec->lock, flags);
1015 }
1016 
1017 void acpi_ec_block_transactions(void)
1018 {
1019 	struct acpi_ec *ec = first_ec;
1020 
1021 	if (!ec)
1022 		return;
1023 
1024 	mutex_lock(&ec->mutex);
1025 	/* Prevent transactions from being carried out */
1026 	acpi_ec_stop(ec, true);
1027 	mutex_unlock(&ec->mutex);
1028 }
1029 
1030 void acpi_ec_unblock_transactions(void)
1031 {
1032 	/*
1033 	 * Allow transactions to happen again (this function is called from
1034 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1035 	 */
1036 	if (first_ec)
1037 		acpi_ec_start(first_ec, true);
1038 }
1039 
1040 /* --------------------------------------------------------------------------
1041                                 Event Management
1042    -------------------------------------------------------------------------- */
1043 static struct acpi_ec_query_handler *
1044 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1045 {
1046 	struct acpi_ec_query_handler *handler;
1047 
1048 	mutex_lock(&ec->mutex);
1049 	list_for_each_entry(handler, &ec->list, node) {
1050 		if (value == handler->query_bit) {
1051 			kref_get(&handler->kref);
1052 			mutex_unlock(&ec->mutex);
1053 			return handler;
1054 		}
1055 	}
1056 	mutex_unlock(&ec->mutex);
1057 	return NULL;
1058 }
1059 
1060 static void acpi_ec_query_handler_release(struct kref *kref)
1061 {
1062 	struct acpi_ec_query_handler *handler =
1063 		container_of(kref, struct acpi_ec_query_handler, kref);
1064 
1065 	kfree(handler);
1066 }
1067 
1068 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1069 {
1070 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1071 }
1072 
1073 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1074 			      acpi_handle handle, acpi_ec_query_func func,
1075 			      void *data)
1076 {
1077 	struct acpi_ec_query_handler *handler =
1078 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1079 
1080 	if (!handler)
1081 		return -ENOMEM;
1082 
1083 	handler->query_bit = query_bit;
1084 	handler->handle = handle;
1085 	handler->func = func;
1086 	handler->data = data;
1087 	mutex_lock(&ec->mutex);
1088 	kref_init(&handler->kref);
1089 	list_add(&handler->node, &ec->list);
1090 	mutex_unlock(&ec->mutex);
1091 	return 0;
1092 }
1093 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1094 
1095 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1096 					  bool remove_all, u8 query_bit)
1097 {
1098 	struct acpi_ec_query_handler *handler, *tmp;
1099 	LIST_HEAD(free_list);
1100 
1101 	mutex_lock(&ec->mutex);
1102 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1103 		if (remove_all || query_bit == handler->query_bit) {
1104 			list_del_init(&handler->node);
1105 			list_add(&handler->node, &free_list);
1106 		}
1107 	}
1108 	mutex_unlock(&ec->mutex);
1109 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1110 		acpi_ec_put_query_handler(handler);
1111 }
1112 
1113 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1114 {
1115 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1116 }
1117 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1118 
1119 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1120 {
1121 	struct acpi_ec_query *q;
1122 	struct transaction *t;
1123 
1124 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1125 	if (!q)
1126 		return NULL;
1127 	INIT_WORK(&q->work, acpi_ec_event_processor);
1128 	t = &q->transaction;
1129 	t->command = ACPI_EC_COMMAND_QUERY;
1130 	t->rdata = pval;
1131 	t->rlen = 1;
1132 	return q;
1133 }
1134 
1135 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1136 {
1137 	if (q) {
1138 		if (q->handler)
1139 			acpi_ec_put_query_handler(q->handler);
1140 		kfree(q);
1141 	}
1142 }
1143 
1144 static void acpi_ec_event_processor(struct work_struct *work)
1145 {
1146 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1147 	struct acpi_ec_query_handler *handler = q->handler;
1148 
1149 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1150 	if (handler->func)
1151 		handler->func(handler->data);
1152 	else if (handler->handle)
1153 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1154 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1155 	acpi_ec_delete_query(q);
1156 }
1157 
1158 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1159 {
1160 	u8 value = 0;
1161 	int result;
1162 	struct acpi_ec_query *q;
1163 
1164 	q = acpi_ec_create_query(&value);
1165 	if (!q)
1166 		return -ENOMEM;
1167 
1168 	/*
1169 	 * Query the EC to find out which _Qxx method we need to evaluate.
1170 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1171 	 * bit to be cleared (and thus clearing the interrupt source).
1172 	 */
1173 	result = acpi_ec_transaction(ec, &q->transaction);
1174 	if (!value)
1175 		result = -ENODATA;
1176 	if (result)
1177 		goto err_exit;
1178 
1179 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1180 	if (!q->handler) {
1181 		result = -ENODATA;
1182 		goto err_exit;
1183 	}
1184 
1185 	/*
1186 	 * It is reported that _Qxx are evaluated in a parallel way on
1187 	 * Windows:
1188 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1189 	 *
1190 	 * Put this log entry before schedule_work() in order to make
1191 	 * it appearing before any other log entries occurred during the
1192 	 * work queue execution.
1193 	 */
1194 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1195 	if (!queue_work(ec_query_wq, &q->work)) {
1196 		ec_dbg_evt("Query(0x%02x) overlapped", value);
1197 		result = -EBUSY;
1198 	}
1199 
1200 err_exit:
1201 	if (result)
1202 		acpi_ec_delete_query(q);
1203 	if (data)
1204 		*data = value;
1205 	return result;
1206 }
1207 
1208 static void acpi_ec_check_event(struct acpi_ec *ec)
1209 {
1210 	unsigned long flags;
1211 
1212 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1213 		if (ec_guard(ec)) {
1214 			spin_lock_irqsave(&ec->lock, flags);
1215 			/*
1216 			 * Take care of the SCI_EVT unless no one else is
1217 			 * taking care of it.
1218 			 */
1219 			if (!ec->curr)
1220 				advance_transaction(ec);
1221 			spin_unlock_irqrestore(&ec->lock, flags);
1222 		}
1223 	}
1224 }
1225 
1226 static void acpi_ec_event_handler(struct work_struct *work)
1227 {
1228 	unsigned long flags;
1229 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1230 
1231 	ec_dbg_evt("Event started");
1232 
1233 	spin_lock_irqsave(&ec->lock, flags);
1234 	while (ec->nr_pending_queries) {
1235 		spin_unlock_irqrestore(&ec->lock, flags);
1236 		(void)acpi_ec_query(ec, NULL);
1237 		spin_lock_irqsave(&ec->lock, flags);
1238 		ec->nr_pending_queries--;
1239 		/*
1240 		 * Before exit, make sure that this work item can be
1241 		 * scheduled again. There might be QR_EC failures, leaving
1242 		 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1243 		 * item from being scheduled again.
1244 		 */
1245 		if (!ec->nr_pending_queries) {
1246 			if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1247 			    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1248 				acpi_ec_complete_query(ec);
1249 		}
1250 	}
1251 	spin_unlock_irqrestore(&ec->lock, flags);
1252 
1253 	ec_dbg_evt("Event stopped");
1254 
1255 	acpi_ec_check_event(ec);
1256 }
1257 
1258 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1259 {
1260 	unsigned long flags;
1261 
1262 	spin_lock_irqsave(&ec->lock, flags);
1263 	advance_transaction(ec);
1264 	spin_unlock_irqrestore(&ec->lock, flags);
1265 }
1266 
1267 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1268 			       u32 gpe_number, void *data)
1269 {
1270 	acpi_ec_handle_interrupt(data);
1271 	return ACPI_INTERRUPT_HANDLED;
1272 }
1273 
1274 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1275 {
1276 	acpi_ec_handle_interrupt(data);
1277 	return IRQ_HANDLED;
1278 }
1279 
1280 /* --------------------------------------------------------------------------
1281  *                           Address Space Management
1282  * -------------------------------------------------------------------------- */
1283 
1284 static acpi_status
1285 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1286 		      u32 bits, u64 *value64,
1287 		      void *handler_context, void *region_context)
1288 {
1289 	struct acpi_ec *ec = handler_context;
1290 	int result = 0, i, bytes = bits / 8;
1291 	u8 *value = (u8 *)value64;
1292 
1293 	if ((address > 0xFF) || !value || !handler_context)
1294 		return AE_BAD_PARAMETER;
1295 
1296 	if (function != ACPI_READ && function != ACPI_WRITE)
1297 		return AE_BAD_PARAMETER;
1298 
1299 	if (ec->busy_polling || bits > 8)
1300 		acpi_ec_burst_enable(ec);
1301 
1302 	for (i = 0; i < bytes; ++i, ++address, ++value)
1303 		result = (function == ACPI_READ) ?
1304 			acpi_ec_read(ec, address, value) :
1305 			acpi_ec_write(ec, address, *value);
1306 
1307 	if (ec->busy_polling || bits > 8)
1308 		acpi_ec_burst_disable(ec);
1309 
1310 	switch (result) {
1311 	case -EINVAL:
1312 		return AE_BAD_PARAMETER;
1313 	case -ENODEV:
1314 		return AE_NOT_FOUND;
1315 	case -ETIME:
1316 		return AE_TIME;
1317 	default:
1318 		return AE_OK;
1319 	}
1320 }
1321 
1322 /* --------------------------------------------------------------------------
1323  *                             Driver Interface
1324  * -------------------------------------------------------------------------- */
1325 
1326 static acpi_status
1327 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1328 
1329 static void acpi_ec_free(struct acpi_ec *ec)
1330 {
1331 	if (first_ec == ec)
1332 		first_ec = NULL;
1333 	if (boot_ec == ec)
1334 		boot_ec = NULL;
1335 	kfree(ec);
1336 }
1337 
1338 static struct acpi_ec *acpi_ec_alloc(void)
1339 {
1340 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1341 
1342 	if (!ec)
1343 		return NULL;
1344 	mutex_init(&ec->mutex);
1345 	init_waitqueue_head(&ec->wait);
1346 	INIT_LIST_HEAD(&ec->list);
1347 	spin_lock_init(&ec->lock);
1348 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1349 	ec->timestamp = jiffies;
1350 	ec->busy_polling = true;
1351 	ec->polling_guard = 0;
1352 	ec->gpe = -1;
1353 	ec->irq = -1;
1354 	return ec;
1355 }
1356 
1357 static acpi_status
1358 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1359 			       void *context, void **return_value)
1360 {
1361 	char node_name[5];
1362 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1363 	struct acpi_ec *ec = context;
1364 	int value = 0;
1365 	acpi_status status;
1366 
1367 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1368 
1369 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1370 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1371 	return AE_OK;
1372 }
1373 
1374 static acpi_status
1375 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1376 {
1377 	acpi_status status;
1378 	unsigned long long tmp = 0;
1379 	struct acpi_ec *ec = context;
1380 
1381 	/* clear addr values, ec_parse_io_ports depend on it */
1382 	ec->command_addr = ec->data_addr = 0;
1383 
1384 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1385 				     ec_parse_io_ports, ec);
1386 	if (ACPI_FAILURE(status))
1387 		return status;
1388 	if (ec->data_addr == 0 || ec->command_addr == 0)
1389 		return AE_OK;
1390 
1391 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1392 		/*
1393 		 * Always inherit the GPE number setting from the ECDT
1394 		 * EC.
1395 		 */
1396 		ec->gpe = boot_ec->gpe;
1397 	} else {
1398 		/* Get GPE bit assignment (EC events). */
1399 		/* TODO: Add support for _GPE returning a package */
1400 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1401 		if (ACPI_SUCCESS(status))
1402 			ec->gpe = tmp;
1403 
1404 		/*
1405 		 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1406 		 * platforms which use GpioInt instead of GPE.
1407 		 */
1408 	}
1409 	/* Use the global lock for all EC transactions? */
1410 	tmp = 0;
1411 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1412 	ec->global_lock = tmp;
1413 	ec->handle = handle;
1414 	return AE_CTRL_TERMINATE;
1415 }
1416 
1417 static bool install_gpe_event_handler(struct acpi_ec *ec)
1418 {
1419 	acpi_status status;
1420 
1421 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1422 					      ACPI_GPE_EDGE_TRIGGERED,
1423 					      &acpi_ec_gpe_handler, ec);
1424 	if (ACPI_FAILURE(status))
1425 		return false;
1426 
1427 	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1428 		acpi_ec_enable_gpe(ec, true);
1429 
1430 	return true;
1431 }
1432 
1433 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1434 {
1435 	return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1436 			   "ACPI EC", ec) >= 0;
1437 }
1438 
1439 /**
1440  * ec_install_handlers - Install service callbacks and register query methods.
1441  * @ec: Target EC.
1442  * @device: ACPI device object corresponding to @ec.
1443  *
1444  * Install a handler for the EC address space type unless it has been installed
1445  * already.  If @device is not NULL, also look for EC query methods in the
1446  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1447  * handler for the EC, if possible.
1448  *
1449  * Return:
1450  * -ENODEV if the address space handler cannot be installed, which means
1451  *  "unable to handle transactions",
1452  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1453  * or 0 (success) otherwise.
1454  */
1455 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1456 {
1457 	acpi_status status;
1458 
1459 	acpi_ec_start(ec, false);
1460 
1461 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1462 		acpi_ec_enter_noirq(ec);
1463 		status = acpi_install_address_space_handler(ec->handle,
1464 							    ACPI_ADR_SPACE_EC,
1465 							    &acpi_ec_space_handler,
1466 							    NULL, ec);
1467 		if (ACPI_FAILURE(status)) {
1468 			acpi_ec_stop(ec, false);
1469 			return -ENODEV;
1470 		}
1471 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1472 	}
1473 
1474 	if (!device)
1475 		return 0;
1476 
1477 	if (ec->gpe < 0) {
1478 		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1479 		int irq = acpi_dev_gpio_irq_get(device, 0);
1480 		/*
1481 		 * Bail out right away for deferred probing or complete the
1482 		 * initialization regardless of any other errors.
1483 		 */
1484 		if (irq == -EPROBE_DEFER)
1485 			return -EPROBE_DEFER;
1486 		else if (irq >= 0)
1487 			ec->irq = irq;
1488 	}
1489 
1490 	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1491 		/* Find and register all query methods */
1492 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1493 				    acpi_ec_register_query_methods,
1494 				    NULL, ec, NULL);
1495 		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1496 	}
1497 	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1498 		bool ready = false;
1499 
1500 		if (ec->gpe >= 0)
1501 			ready = install_gpe_event_handler(ec);
1502 		else if (ec->irq >= 0)
1503 			ready = install_gpio_irq_event_handler(ec);
1504 
1505 		if (ready) {
1506 			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1507 			acpi_ec_leave_noirq(ec);
1508 		}
1509 		/*
1510 		 * Failures to install an event handler are not fatal, because
1511 		 * the EC can be polled for events.
1512 		 */
1513 	}
1514 	/* EC is fully operational, allow queries */
1515 	acpi_ec_enable_event(ec);
1516 
1517 	return 0;
1518 }
1519 
1520 static void ec_remove_handlers(struct acpi_ec *ec)
1521 {
1522 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1523 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1524 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1525 			pr_err("failed to remove space handler\n");
1526 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1527 	}
1528 
1529 	/*
1530 	 * Stops handling the EC transactions after removing the operation
1531 	 * region handler. This is required because _REG(DISCONNECT)
1532 	 * invoked during the removal can result in new EC transactions.
1533 	 *
1534 	 * Flushes the EC requests and thus disables the GPE before
1535 	 * removing the GPE handler. This is required by the current ACPICA
1536 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1537 	 * it is indicated but there is no way to handle it. So the drivers
1538 	 * must disable the GPEs prior to removing the GPE handlers.
1539 	 */
1540 	acpi_ec_stop(ec, false);
1541 
1542 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1543 		if (ec->gpe >= 0 &&
1544 		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1545 				 &acpi_ec_gpe_handler)))
1546 			pr_err("failed to remove gpe handler\n");
1547 
1548 		if (ec->irq >= 0)
1549 			free_irq(ec->irq, ec);
1550 
1551 		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1552 	}
1553 	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1554 		acpi_ec_remove_query_handlers(ec, true, 0);
1555 		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1556 	}
1557 }
1558 
1559 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1560 {
1561 	int ret;
1562 
1563 	ret = ec_install_handlers(ec, device);
1564 	if (ret)
1565 		return ret;
1566 
1567 	/* First EC capable of handling transactions */
1568 	if (!first_ec)
1569 		first_ec = ec;
1570 
1571 	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1572 		ec->data_addr);
1573 
1574 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1575 		if (ec->gpe >= 0)
1576 			pr_info("GPE=0x%x\n", ec->gpe);
1577 		else
1578 			pr_info("IRQ=%d\n", ec->irq);
1579 	}
1580 
1581 	return ret;
1582 }
1583 
1584 static int acpi_ec_add(struct acpi_device *device)
1585 {
1586 	struct acpi_ec *ec;
1587 	int ret;
1588 
1589 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1590 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1591 
1592 	if (boot_ec && (boot_ec->handle == device->handle ||
1593 	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1594 		/* Fast path: this device corresponds to the boot EC. */
1595 		ec = boot_ec;
1596 	} else {
1597 		acpi_status status;
1598 
1599 		ec = acpi_ec_alloc();
1600 		if (!ec)
1601 			return -ENOMEM;
1602 
1603 		status = ec_parse_device(device->handle, 0, ec, NULL);
1604 		if (status != AE_CTRL_TERMINATE) {
1605 			ret = -EINVAL;
1606 			goto err;
1607 		}
1608 
1609 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1610 		    ec->data_addr == boot_ec->data_addr) {
1611 			/*
1612 			 * Trust PNP0C09 namespace location rather than
1613 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1614 			 * because of ASUS quirks, so do not change
1615 			 * boot_ec->gpe to ec->gpe.
1616 			 */
1617 			boot_ec->handle = ec->handle;
1618 			acpi_handle_debug(ec->handle, "duplicated.\n");
1619 			acpi_ec_free(ec);
1620 			ec = boot_ec;
1621 		}
1622 	}
1623 
1624 	ret = acpi_ec_setup(ec, device);
1625 	if (ret)
1626 		goto err;
1627 
1628 	if (ec == boot_ec)
1629 		acpi_handle_info(boot_ec->handle,
1630 				 "Boot %s EC initialization complete\n",
1631 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1632 
1633 	acpi_handle_info(ec->handle,
1634 			 "EC: Used to handle transactions and events\n");
1635 
1636 	device->driver_data = ec;
1637 
1638 	ret = !!request_region(ec->data_addr, 1, "EC data");
1639 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1640 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1641 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1642 
1643 	/* Reprobe devices depending on the EC */
1644 	acpi_walk_dep_device_list(ec->handle);
1645 
1646 	acpi_handle_debug(ec->handle, "enumerated.\n");
1647 	return 0;
1648 
1649 err:
1650 	if (ec != boot_ec)
1651 		acpi_ec_free(ec);
1652 
1653 	return ret;
1654 }
1655 
1656 static int acpi_ec_remove(struct acpi_device *device)
1657 {
1658 	struct acpi_ec *ec;
1659 
1660 	if (!device)
1661 		return -EINVAL;
1662 
1663 	ec = acpi_driver_data(device);
1664 	release_region(ec->data_addr, 1);
1665 	release_region(ec->command_addr, 1);
1666 	device->driver_data = NULL;
1667 	if (ec != boot_ec) {
1668 		ec_remove_handlers(ec);
1669 		acpi_ec_free(ec);
1670 	}
1671 	return 0;
1672 }
1673 
1674 static acpi_status
1675 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1676 {
1677 	struct acpi_ec *ec = context;
1678 
1679 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1680 		return AE_OK;
1681 
1682 	/*
1683 	 * The first address region returned is the data port, and
1684 	 * the second address region returned is the status/command
1685 	 * port.
1686 	 */
1687 	if (ec->data_addr == 0)
1688 		ec->data_addr = resource->data.io.minimum;
1689 	else if (ec->command_addr == 0)
1690 		ec->command_addr = resource->data.io.minimum;
1691 	else
1692 		return AE_CTRL_TERMINATE;
1693 
1694 	return AE_OK;
1695 }
1696 
1697 static const struct acpi_device_id ec_device_ids[] = {
1698 	{"PNP0C09", 0},
1699 	{ACPI_ECDT_HID, 0},
1700 	{"", 0},
1701 };
1702 
1703 /*
1704  * This function is not Windows-compatible as Windows never enumerates the
1705  * namespace EC before the main ACPI device enumeration process. It is
1706  * retained for historical reason and will be deprecated in the future.
1707  */
1708 void __init acpi_ec_dsdt_probe(void)
1709 {
1710 	struct acpi_ec *ec;
1711 	acpi_status status;
1712 	int ret;
1713 
1714 	/*
1715 	 * If a platform has ECDT, there is no need to proceed as the
1716 	 * following probe is not a part of the ACPI device enumeration,
1717 	 * executing _STA is not safe, and thus this probe may risk of
1718 	 * picking up an invalid EC device.
1719 	 */
1720 	if (boot_ec)
1721 		return;
1722 
1723 	ec = acpi_ec_alloc();
1724 	if (!ec)
1725 		return;
1726 
1727 	/*
1728 	 * At this point, the namespace is initialized, so start to find
1729 	 * the namespace objects.
1730 	 */
1731 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1732 	if (ACPI_FAILURE(status) || !ec->handle) {
1733 		acpi_ec_free(ec);
1734 		return;
1735 	}
1736 
1737 	/*
1738 	 * When the DSDT EC is available, always re-configure boot EC to
1739 	 * have _REG evaluated. _REG can only be evaluated after the
1740 	 * namespace initialization.
1741 	 * At this point, the GPE is not fully initialized, so do not to
1742 	 * handle the events.
1743 	 */
1744 	ret = acpi_ec_setup(ec, NULL);
1745 	if (ret) {
1746 		acpi_ec_free(ec);
1747 		return;
1748 	}
1749 
1750 	boot_ec = ec;
1751 
1752 	acpi_handle_info(ec->handle,
1753 			 "Boot DSDT EC used to handle transactions\n");
1754 }
1755 
1756 /*
1757  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1758  *
1759  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1760  * found a matching object in the namespace.
1761  *
1762  * Next, in case the DSDT EC is not functioning, it is still necessary to
1763  * provide a functional ECDT EC to handle events, so add an extra device object
1764  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1765  *
1766  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1767  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1768  */
1769 static void __init acpi_ec_ecdt_start(void)
1770 {
1771 	struct acpi_table_ecdt *ecdt_ptr;
1772 	acpi_handle handle;
1773 	acpi_status status;
1774 
1775 	/* Bail out if a matching EC has been found in the namespace. */
1776 	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1777 		return;
1778 
1779 	/* Look up the object pointed to from the ECDT in the namespace. */
1780 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1781 				(struct acpi_table_header **)&ecdt_ptr);
1782 	if (ACPI_FAILURE(status))
1783 		return;
1784 
1785 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1786 	if (ACPI_FAILURE(status))
1787 		return;
1788 
1789 	boot_ec->handle = handle;
1790 
1791 	/* Add a special ACPI device object to represent the boot EC. */
1792 	acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1793 }
1794 
1795 /*
1796  * On some hardware it is necessary to clear events accumulated by the EC during
1797  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1798  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1799  *
1800  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1801  *
1802  * Ideally, the EC should also be instructed NOT to accumulate events during
1803  * sleep (which Windows seems to do somehow), but the interface to control this
1804  * behaviour is not known at this time.
1805  *
1806  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1807  * however it is very likely that other Samsung models are affected.
1808  *
1809  * On systems which don't accumulate _Q events during sleep, this extra check
1810  * should be harmless.
1811  */
1812 static int ec_clear_on_resume(const struct dmi_system_id *id)
1813 {
1814 	pr_debug("Detected system needing EC poll on resume.\n");
1815 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1816 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1817 	return 0;
1818 }
1819 
1820 /*
1821  * Some ECDTs contain wrong register addresses.
1822  * MSI MS-171F
1823  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1824  */
1825 static int ec_correct_ecdt(const struct dmi_system_id *id)
1826 {
1827 	pr_debug("Detected system needing ECDT address correction.\n");
1828 	EC_FLAGS_CORRECT_ECDT = 1;
1829 	return 0;
1830 }
1831 
1832 /*
1833  * Some DSDTs contain wrong GPE setting.
1834  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1835  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1836  */
1837 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1838 {
1839 	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1840 	EC_FLAGS_IGNORE_DSDT_GPE = 1;
1841 	return 0;
1842 }
1843 
1844 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1845 	{
1846 	ec_correct_ecdt, "MSI MS-171F", {
1847 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1848 	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1849 	{
1850 	ec_honor_ecdt_gpe, "ASUS FX502VD", {
1851 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1852 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1853 	{
1854 	ec_honor_ecdt_gpe, "ASUS FX502VE", {
1855 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1856 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1857 	{
1858 	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1859 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1860 	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1861 	{
1862 	ec_honor_ecdt_gpe, "ASUS X550VXK", {
1863 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1864 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1865 	{
1866 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1867 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1868 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1869 	{
1870 	ec_clear_on_resume, "Samsung hardware", {
1871 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1872 	{},
1873 };
1874 
1875 void __init acpi_ec_ecdt_probe(void)
1876 {
1877 	struct acpi_table_ecdt *ecdt_ptr;
1878 	struct acpi_ec *ec;
1879 	acpi_status status;
1880 	int ret;
1881 
1882 	/* Generate a boot ec context. */
1883 	dmi_check_system(ec_dmi_table);
1884 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1885 				(struct acpi_table_header **)&ecdt_ptr);
1886 	if (ACPI_FAILURE(status))
1887 		return;
1888 
1889 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1890 		/*
1891 		 * Asus X50GL:
1892 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1893 		 */
1894 		return;
1895 	}
1896 
1897 	ec = acpi_ec_alloc();
1898 	if (!ec)
1899 		return;
1900 
1901 	if (EC_FLAGS_CORRECT_ECDT) {
1902 		ec->command_addr = ecdt_ptr->data.address;
1903 		ec->data_addr = ecdt_ptr->control.address;
1904 	} else {
1905 		ec->command_addr = ecdt_ptr->control.address;
1906 		ec->data_addr = ecdt_ptr->data.address;
1907 	}
1908 
1909 	/*
1910 	 * Ignore the GPE value on Reduced Hardware platforms.
1911 	 * Some products have this set to an erroneous value.
1912 	 */
1913 	if (!acpi_gbl_reduced_hardware)
1914 		ec->gpe = ecdt_ptr->gpe;
1915 
1916 	ec->handle = ACPI_ROOT_OBJECT;
1917 
1918 	/*
1919 	 * At this point, the namespace is not initialized, so do not find
1920 	 * the namespace objects, or handle the events.
1921 	 */
1922 	ret = acpi_ec_setup(ec, NULL);
1923 	if (ret) {
1924 		acpi_ec_free(ec);
1925 		return;
1926 	}
1927 
1928 	boot_ec = ec;
1929 	boot_ec_is_ecdt = true;
1930 
1931 	pr_info("Boot ECDT EC used to handle transactions\n");
1932 }
1933 
1934 #ifdef CONFIG_PM_SLEEP
1935 static int acpi_ec_suspend(struct device *dev)
1936 {
1937 	struct acpi_ec *ec =
1938 		acpi_driver_data(to_acpi_device(dev));
1939 
1940 	if (!pm_suspend_no_platform() && ec_freeze_events)
1941 		acpi_ec_disable_event(ec);
1942 	return 0;
1943 }
1944 
1945 static int acpi_ec_suspend_noirq(struct device *dev)
1946 {
1947 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1948 
1949 	/*
1950 	 * The SCI handler doesn't run at this point, so the GPE can be
1951 	 * masked at the low level without side effects.
1952 	 */
1953 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1954 	    ec->gpe >= 0 && ec->reference_count >= 1)
1955 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1956 
1957 	acpi_ec_enter_noirq(ec);
1958 
1959 	return 0;
1960 }
1961 
1962 static int acpi_ec_resume_noirq(struct device *dev)
1963 {
1964 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1965 
1966 	acpi_ec_leave_noirq(ec);
1967 
1968 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1969 	    ec->gpe >= 0 && ec->reference_count >= 1)
1970 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1971 
1972 	return 0;
1973 }
1974 
1975 static int acpi_ec_resume(struct device *dev)
1976 {
1977 	struct acpi_ec *ec =
1978 		acpi_driver_data(to_acpi_device(dev));
1979 
1980 	acpi_ec_enable_event(ec);
1981 	return 0;
1982 }
1983 
1984 void acpi_ec_mark_gpe_for_wake(void)
1985 {
1986 	if (first_ec && !ec_no_wakeup)
1987 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1988 }
1989 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
1990 
1991 void acpi_ec_set_gpe_wake_mask(u8 action)
1992 {
1993 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
1994 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1995 }
1996 
1997 bool acpi_ec_other_gpes_active(void)
1998 {
1999 	return acpi_any_gpe_status_set(first_ec ? first_ec->gpe : U32_MAX);
2000 }
2001 
2002 bool acpi_ec_dispatch_gpe(void)
2003 {
2004 	u32 ret;
2005 
2006 	if (!first_ec)
2007 		return false;
2008 
2009 	ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2010 	if (ret == ACPI_INTERRUPT_HANDLED) {
2011 		pm_pr_dbg("EC GPE dispatched\n");
2012 		return true;
2013 	}
2014 	return false;
2015 }
2016 #endif /* CONFIG_PM_SLEEP */
2017 
2018 static const struct dev_pm_ops acpi_ec_pm = {
2019 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2020 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2021 };
2022 
2023 static int param_set_event_clearing(const char *val,
2024 				    const struct kernel_param *kp)
2025 {
2026 	int result = 0;
2027 
2028 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2029 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2030 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2031 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2032 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2033 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2034 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2035 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2036 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2037 	} else
2038 		result = -EINVAL;
2039 	return result;
2040 }
2041 
2042 static int param_get_event_clearing(char *buffer,
2043 				    const struct kernel_param *kp)
2044 {
2045 	switch (ec_event_clearing) {
2046 	case ACPI_EC_EVT_TIMING_STATUS:
2047 		return sprintf(buffer, "status");
2048 	case ACPI_EC_EVT_TIMING_QUERY:
2049 		return sprintf(buffer, "query");
2050 	case ACPI_EC_EVT_TIMING_EVENT:
2051 		return sprintf(buffer, "event");
2052 	default:
2053 		return sprintf(buffer, "invalid");
2054 	}
2055 	return 0;
2056 }
2057 
2058 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2059 		  NULL, 0644);
2060 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2061 
2062 static struct acpi_driver acpi_ec_driver = {
2063 	.name = "ec",
2064 	.class = ACPI_EC_CLASS,
2065 	.ids = ec_device_ids,
2066 	.ops = {
2067 		.add = acpi_ec_add,
2068 		.remove = acpi_ec_remove,
2069 		},
2070 	.drv.pm = &acpi_ec_pm,
2071 };
2072 
2073 static void acpi_ec_destroy_workqueues(void)
2074 {
2075 	if (ec_wq) {
2076 		destroy_workqueue(ec_wq);
2077 		ec_wq = NULL;
2078 	}
2079 	if (ec_query_wq) {
2080 		destroy_workqueue(ec_query_wq);
2081 		ec_query_wq = NULL;
2082 	}
2083 }
2084 
2085 static int acpi_ec_init_workqueues(void)
2086 {
2087 	if (!ec_wq)
2088 		ec_wq = alloc_ordered_workqueue("kec", 0);
2089 
2090 	if (!ec_query_wq)
2091 		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2092 
2093 	if (!ec_wq || !ec_query_wq) {
2094 		acpi_ec_destroy_workqueues();
2095 		return -ENODEV;
2096 	}
2097 	return 0;
2098 }
2099 
2100 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2101 	{
2102 		.ident = "Thinkpad X1 Carbon 6th",
2103 		.matches = {
2104 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2105 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2106 		},
2107 	},
2108 	{
2109 		.ident = "ThinkPad X1 Carbon 6th",
2110 		.matches = {
2111 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2112 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2113 		},
2114 	},
2115 	{
2116 		.ident = "ThinkPad X1 Yoga 3rd",
2117 		.matches = {
2118 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2119 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2120 		},
2121 	},
2122 	{ },
2123 };
2124 
2125 void __init acpi_ec_init(void)
2126 {
2127 	int result;
2128 
2129 	result = acpi_ec_init_workqueues();
2130 	if (result)
2131 		return;
2132 
2133 	/*
2134 	 * Disable EC wakeup on following systems to prevent periodic
2135 	 * wakeup from EC GPE.
2136 	 */
2137 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2138 		ec_no_wakeup = true;
2139 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2140 	}
2141 
2142 	/* Driver must be registered after acpi_ec_init_workqueues(). */
2143 	acpi_bus_register_driver(&acpi_ec_driver);
2144 
2145 	acpi_ec_ecdt_start();
2146 }
2147 
2148 /* EC driver currently not unloadable */
2149 #if 0
2150 static void __exit acpi_ec_exit(void)
2151 {
2152 
2153 	acpi_bus_unregister_driver(&acpi_ec_driver);
2154 	acpi_ec_destroy_workqueues();
2155 }
2156 #endif	/* 0 */
2157