xref: /linux/drivers/acpi/ec.c (revision 15a1fbdcfb519c2bd291ed01c6c94e0b89537a77)
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_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
186 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
187 static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
188 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
189 
190 /* --------------------------------------------------------------------------
191  *                           Logging/Debugging
192  * -------------------------------------------------------------------------- */
193 
194 /*
195  * Splitters used by the developers to track the boundary of the EC
196  * handling processes.
197  */
198 #ifdef DEBUG
199 #define EC_DBG_SEP	" "
200 #define EC_DBG_DRV	"+++++"
201 #define EC_DBG_STM	"====="
202 #define EC_DBG_REQ	"*****"
203 #define EC_DBG_EVT	"#####"
204 #else
205 #define EC_DBG_SEP	""
206 #define EC_DBG_DRV
207 #define EC_DBG_STM
208 #define EC_DBG_REQ
209 #define EC_DBG_EVT
210 #endif
211 
212 #define ec_log_raw(fmt, ...) \
213 	pr_info(fmt "\n", ##__VA_ARGS__)
214 #define ec_dbg_raw(fmt, ...) \
215 	pr_debug(fmt "\n", ##__VA_ARGS__)
216 #define ec_log(filter, fmt, ...) \
217 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
218 #define ec_dbg(filter, fmt, ...) \
219 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
220 
221 #define ec_log_drv(fmt, ...) \
222 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
223 #define ec_dbg_drv(fmt, ...) \
224 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
225 #define ec_dbg_stm(fmt, ...) \
226 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
227 #define ec_dbg_req(fmt, ...) \
228 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
229 #define ec_dbg_evt(fmt, ...) \
230 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
231 #define ec_dbg_ref(ec, fmt, ...) \
232 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
233 
234 /* --------------------------------------------------------------------------
235  *                           Device Flags
236  * -------------------------------------------------------------------------- */
237 
238 static bool acpi_ec_started(struct acpi_ec *ec)
239 {
240 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
241 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
242 }
243 
244 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
245 {
246 	/*
247 	 * There is an OSPM early stage logic. During the early stages
248 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
249 	 * the EC transactions are allowed to be performed.
250 	 */
251 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
252 		return false;
253 	/*
254 	 * However, disabling the event handling is experimental for late
255 	 * stage (suspend), and is controlled by the boot parameter of
256 	 * "ec_freeze_events":
257 	 * 1. true:  The EC event handling is disabled before entering
258 	 *           the noirq stage.
259 	 * 2. false: The EC event handling is automatically disabled as
260 	 *           soon as the EC driver is stopped.
261 	 */
262 	if (ec_freeze_events)
263 		return acpi_ec_started(ec);
264 	else
265 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
266 }
267 
268 static bool acpi_ec_flushed(struct acpi_ec *ec)
269 {
270 	return ec->reference_count == 1;
271 }
272 
273 /* --------------------------------------------------------------------------
274  *                           EC Registers
275  * -------------------------------------------------------------------------- */
276 
277 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
278 {
279 	u8 x = inb(ec->command_addr);
280 
281 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
282 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
283 		   x,
284 		   !!(x & ACPI_EC_FLAG_SCI),
285 		   !!(x & ACPI_EC_FLAG_BURST),
286 		   !!(x & ACPI_EC_FLAG_CMD),
287 		   !!(x & ACPI_EC_FLAG_IBF),
288 		   !!(x & ACPI_EC_FLAG_OBF));
289 	return x;
290 }
291 
292 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
293 {
294 	u8 x = inb(ec->data_addr);
295 
296 	ec->timestamp = jiffies;
297 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
298 	return x;
299 }
300 
301 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
302 {
303 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
304 	outb(command, ec->command_addr);
305 	ec->timestamp = jiffies;
306 }
307 
308 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
309 {
310 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
311 	outb(data, ec->data_addr);
312 	ec->timestamp = jiffies;
313 }
314 
315 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
316 static const char *acpi_ec_cmd_string(u8 cmd)
317 {
318 	switch (cmd) {
319 	case 0x80:
320 		return "RD_EC";
321 	case 0x81:
322 		return "WR_EC";
323 	case 0x82:
324 		return "BE_EC";
325 	case 0x83:
326 		return "BD_EC";
327 	case 0x84:
328 		return "QR_EC";
329 	}
330 	return "UNKNOWN";
331 }
332 #else
333 #define acpi_ec_cmd_string(cmd)		"UNDEF"
334 #endif
335 
336 /* --------------------------------------------------------------------------
337  *                           GPE Registers
338  * -------------------------------------------------------------------------- */
339 
340 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
341 {
342 	acpi_event_status gpe_status = 0;
343 
344 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
345 	return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
346 }
347 
348 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
349 {
350 	if (open)
351 		acpi_enable_gpe(NULL, ec->gpe);
352 	else {
353 		BUG_ON(ec->reference_count < 1);
354 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
355 	}
356 	if (acpi_ec_is_gpe_raised(ec)) {
357 		/*
358 		 * On some platforms, EN=1 writes cannot trigger GPE. So
359 		 * software need to manually trigger a pseudo GPE event on
360 		 * EN=1 writes.
361 		 */
362 		ec_dbg_raw("Polling quirk");
363 		advance_transaction(ec);
364 	}
365 }
366 
367 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
368 {
369 	if (close)
370 		acpi_disable_gpe(NULL, ec->gpe);
371 	else {
372 		BUG_ON(ec->reference_count < 1);
373 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
374 	}
375 }
376 
377 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
378 {
379 	/*
380 	 * GPE STS is a W1C register, which means:
381 	 * 1. Software can clear it without worrying about clearing other
382 	 *    GPEs' STS bits when the hardware sets them in parallel.
383 	 * 2. As long as software can ensure only clearing it when it is
384 	 *    set, hardware won't set it in parallel.
385 	 * So software can clear GPE in any contexts.
386 	 * Warning: do not move the check into advance_transaction() as the
387 	 * EC commands will be sent without GPE raised.
388 	 */
389 	if (!acpi_ec_is_gpe_raised(ec))
390 		return;
391 	acpi_clear_gpe(NULL, ec->gpe);
392 }
393 
394 /* --------------------------------------------------------------------------
395  *                           Transaction Management
396  * -------------------------------------------------------------------------- */
397 
398 static void acpi_ec_submit_request(struct acpi_ec *ec)
399 {
400 	ec->reference_count++;
401 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
402 	    ec->gpe >= 0 && ec->reference_count == 1)
403 		acpi_ec_enable_gpe(ec, true);
404 }
405 
406 static void acpi_ec_complete_request(struct acpi_ec *ec)
407 {
408 	bool flushed = false;
409 
410 	ec->reference_count--;
411 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
412 	    ec->gpe >= 0 && ec->reference_count == 0)
413 		acpi_ec_disable_gpe(ec, true);
414 	flushed = acpi_ec_flushed(ec);
415 	if (flushed)
416 		wake_up(&ec->wait);
417 }
418 
419 static void acpi_ec_mask_events(struct acpi_ec *ec)
420 {
421 	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
422 		if (ec->gpe >= 0)
423 			acpi_ec_disable_gpe(ec, false);
424 		else
425 			disable_irq_nosync(ec->irq);
426 
427 		ec_dbg_drv("Polling enabled");
428 		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
429 	}
430 }
431 
432 static void acpi_ec_unmask_events(struct acpi_ec *ec)
433 {
434 	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
435 		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
436 		if (ec->gpe >= 0)
437 			acpi_ec_enable_gpe(ec, false);
438 		else
439 			enable_irq(ec->irq);
440 
441 		ec_dbg_drv("Polling disabled");
442 	}
443 }
444 
445 /*
446  * acpi_ec_submit_flushable_request() - Increase the reference count unless
447  *                                      the flush operation is not in
448  *                                      progress
449  * @ec: the EC device
450  *
451  * This function must be used before taking a new action that should hold
452  * the reference count.  If this function returns false, then the action
453  * must be discarded or it will prevent the flush operation from being
454  * completed.
455  */
456 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
457 {
458 	if (!acpi_ec_started(ec))
459 		return false;
460 	acpi_ec_submit_request(ec);
461 	return true;
462 }
463 
464 static void acpi_ec_submit_query(struct acpi_ec *ec)
465 {
466 	acpi_ec_mask_events(ec);
467 	if (!acpi_ec_event_enabled(ec))
468 		return;
469 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
470 		ec_dbg_evt("Command(%s) submitted/blocked",
471 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
472 		ec->nr_pending_queries++;
473 		queue_work(ec_wq, &ec->work);
474 	}
475 }
476 
477 static void acpi_ec_complete_query(struct acpi_ec *ec)
478 {
479 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
480 		ec_dbg_evt("Command(%s) unblocked",
481 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
482 	acpi_ec_unmask_events(ec);
483 }
484 
485 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
486 {
487 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
488 		ec_log_drv("event unblocked");
489 	/*
490 	 * Unconditionally invoke this once after enabling the event
491 	 * handling mechanism to detect the pending events.
492 	 */
493 	advance_transaction(ec);
494 }
495 
496 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
497 {
498 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
499 		ec_log_drv("event blocked");
500 }
501 
502 /*
503  * Process _Q events that might have accumulated in the EC.
504  * Run with locked ec mutex.
505  */
506 static void acpi_ec_clear(struct acpi_ec *ec)
507 {
508 	int i, status;
509 	u8 value = 0;
510 
511 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
512 		status = acpi_ec_query(ec, &value);
513 		if (status || !value)
514 			break;
515 	}
516 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
517 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
518 	else
519 		pr_info("%d stale EC events cleared\n", i);
520 }
521 
522 static void acpi_ec_enable_event(struct acpi_ec *ec)
523 {
524 	unsigned long flags;
525 
526 	spin_lock_irqsave(&ec->lock, flags);
527 	if (acpi_ec_started(ec))
528 		__acpi_ec_enable_event(ec);
529 	spin_unlock_irqrestore(&ec->lock, flags);
530 
531 	/* Drain additional events if hardware requires that */
532 	if (EC_FLAGS_CLEAR_ON_RESUME)
533 		acpi_ec_clear(ec);
534 }
535 
536 #ifdef CONFIG_PM_SLEEP
537 static void __acpi_ec_flush_work(void)
538 {
539 	drain_workqueue(ec_wq); /* flush ec->work */
540 	flush_workqueue(ec_query_wq); /* flush queries */
541 }
542 
543 static void acpi_ec_disable_event(struct acpi_ec *ec)
544 {
545 	unsigned long flags;
546 
547 	spin_lock_irqsave(&ec->lock, flags);
548 	__acpi_ec_disable_event(ec);
549 	spin_unlock_irqrestore(&ec->lock, flags);
550 
551 	/*
552 	 * When ec_freeze_events is true, we need to flush events in
553 	 * the proper position before entering the noirq stage.
554 	 */
555 	__acpi_ec_flush_work();
556 }
557 
558 void acpi_ec_flush_work(void)
559 {
560 	/* Without ec_wq there is nothing to flush. */
561 	if (!ec_wq)
562 		return;
563 
564 	__acpi_ec_flush_work();
565 }
566 #endif /* CONFIG_PM_SLEEP */
567 
568 static bool acpi_ec_guard_event(struct acpi_ec *ec)
569 {
570 	bool guarded = true;
571 	unsigned long flags;
572 
573 	spin_lock_irqsave(&ec->lock, flags);
574 	/*
575 	 * If firmware SCI_EVT clearing timing is "event", we actually
576 	 * don't know when the SCI_EVT will be cleared by firmware after
577 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
578 	 * acceptable period.
579 	 *
580 	 * The guarding period begins when EC_FLAGS_QUERY_PENDING is
581 	 * flagged, which means SCI_EVT check has just been performed.
582 	 * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
583 	 * guarding should have already been performed (via
584 	 * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
585 	 * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
586 	 * ACPI_EC_COMMAND_POLL state immediately.
587 	 */
588 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
589 	    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
590 	    !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
591 	    (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
592 		guarded = false;
593 	spin_unlock_irqrestore(&ec->lock, flags);
594 	return guarded;
595 }
596 
597 static int ec_transaction_polled(struct acpi_ec *ec)
598 {
599 	unsigned long flags;
600 	int ret = 0;
601 
602 	spin_lock_irqsave(&ec->lock, flags);
603 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
604 		ret = 1;
605 	spin_unlock_irqrestore(&ec->lock, flags);
606 	return ret;
607 }
608 
609 static int ec_transaction_completed(struct acpi_ec *ec)
610 {
611 	unsigned long flags;
612 	int ret = 0;
613 
614 	spin_lock_irqsave(&ec->lock, flags);
615 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
616 		ret = 1;
617 	spin_unlock_irqrestore(&ec->lock, flags);
618 	return ret;
619 }
620 
621 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
622 {
623 	ec->curr->flags |= flag;
624 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
625 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
626 		    flag == ACPI_EC_COMMAND_POLL)
627 			acpi_ec_complete_query(ec);
628 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
629 		    flag == ACPI_EC_COMMAND_COMPLETE)
630 			acpi_ec_complete_query(ec);
631 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
632 		    flag == ACPI_EC_COMMAND_COMPLETE)
633 			set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
634 	}
635 }
636 
637 static void advance_transaction(struct acpi_ec *ec)
638 {
639 	struct transaction *t;
640 	u8 status;
641 	bool wakeup = false;
642 
643 	ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
644 		   smp_processor_id());
645 	/*
646 	 * By always clearing STS before handling all indications, we can
647 	 * ensure a hardware STS 0->1 change after this clearing can always
648 	 * trigger a GPE interrupt.
649 	 */
650 	if (ec->gpe >= 0)
651 		acpi_ec_clear_gpe(ec);
652 
653 	status = acpi_ec_read_status(ec);
654 	t = ec->curr;
655 	/*
656 	 * Another IRQ or a guarded polling mode advancement is detected,
657 	 * the next QR_EC submission is then allowed.
658 	 */
659 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
660 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
661 		    (!ec->nr_pending_queries ||
662 		     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
663 			clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
664 			acpi_ec_complete_query(ec);
665 		}
666 	}
667 	if (!t)
668 		goto err;
669 	if (t->flags & ACPI_EC_COMMAND_POLL) {
670 		if (t->wlen > t->wi) {
671 			if ((status & ACPI_EC_FLAG_IBF) == 0)
672 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
673 			else
674 				goto err;
675 		} else if (t->rlen > t->ri) {
676 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
677 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
678 				if (t->rlen == t->ri) {
679 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
680 					if (t->command == ACPI_EC_COMMAND_QUERY)
681 						ec_dbg_evt("Command(%s) completed by hardware",
682 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
683 					wakeup = true;
684 				}
685 			} else
686 				goto err;
687 		} else if (t->wlen == t->wi &&
688 			   (status & ACPI_EC_FLAG_IBF) == 0) {
689 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
690 			wakeup = true;
691 		}
692 		goto out;
693 	} else {
694 		if (EC_FLAGS_QUERY_HANDSHAKE &&
695 		    !(status & ACPI_EC_FLAG_SCI) &&
696 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
697 			ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
698 			t->rdata[t->ri++] = 0x00;
699 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
700 			ec_dbg_evt("Command(%s) completed by software",
701 				   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
702 			wakeup = true;
703 		} else if ((status & ACPI_EC_FLAG_IBF) == 0) {
704 			acpi_ec_write_cmd(ec, t->command);
705 			ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
706 		} else
707 			goto err;
708 		goto out;
709 	}
710 err:
711 	/*
712 	 * If SCI bit is set, then don't think it's a false IRQ
713 	 * otherwise will take a not handled IRQ as a false one.
714 	 */
715 	if (!(status & ACPI_EC_FLAG_SCI)) {
716 		if (in_interrupt() && t) {
717 			if (t->irq_count < ec_storm_threshold)
718 				++t->irq_count;
719 			/* Allow triggering on 0 threshold */
720 			if (t->irq_count == ec_storm_threshold)
721 				acpi_ec_mask_events(ec);
722 		}
723 	}
724 out:
725 	if (status & ACPI_EC_FLAG_SCI)
726 		acpi_ec_submit_query(ec);
727 	if (wakeup && in_interrupt())
728 		wake_up(&ec->wait);
729 }
730 
731 static void start_transaction(struct acpi_ec *ec)
732 {
733 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
734 	ec->curr->flags = 0;
735 }
736 
737 static int ec_guard(struct acpi_ec *ec)
738 {
739 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
740 	unsigned long timeout = ec->timestamp + guard;
741 
742 	/* Ensure guarding period before polling EC status */
743 	do {
744 		if (ec->busy_polling) {
745 			/* Perform busy polling */
746 			if (ec_transaction_completed(ec))
747 				return 0;
748 			udelay(jiffies_to_usecs(guard));
749 		} else {
750 			/*
751 			 * Perform wait polling
752 			 * 1. Wait the transaction to be completed by the
753 			 *    GPE handler after the transaction enters
754 			 *    ACPI_EC_COMMAND_POLL state.
755 			 * 2. A special guarding logic is also required
756 			 *    for event clearing mode "event" before the
757 			 *    transaction enters ACPI_EC_COMMAND_POLL
758 			 *    state.
759 			 */
760 			if (!ec_transaction_polled(ec) &&
761 			    !acpi_ec_guard_event(ec))
762 				break;
763 			if (wait_event_timeout(ec->wait,
764 					       ec_transaction_completed(ec),
765 					       guard))
766 				return 0;
767 		}
768 	} while (time_before(jiffies, timeout));
769 	return -ETIME;
770 }
771 
772 static int ec_poll(struct acpi_ec *ec)
773 {
774 	unsigned long flags;
775 	int repeat = 5; /* number of command restarts */
776 
777 	while (repeat--) {
778 		unsigned long delay = jiffies +
779 			msecs_to_jiffies(ec_delay);
780 		do {
781 			if (!ec_guard(ec))
782 				return 0;
783 			spin_lock_irqsave(&ec->lock, flags);
784 			advance_transaction(ec);
785 			spin_unlock_irqrestore(&ec->lock, flags);
786 		} while (time_before(jiffies, delay));
787 		pr_debug("controller reset, restart transaction\n");
788 		spin_lock_irqsave(&ec->lock, flags);
789 		start_transaction(ec);
790 		spin_unlock_irqrestore(&ec->lock, flags);
791 	}
792 	return -ETIME;
793 }
794 
795 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
796 					struct transaction *t)
797 {
798 	unsigned long tmp;
799 	int ret = 0;
800 
801 	/* start transaction */
802 	spin_lock_irqsave(&ec->lock, tmp);
803 	/* Enable GPE for command processing (IBF=0/OBF=1) */
804 	if (!acpi_ec_submit_flushable_request(ec)) {
805 		ret = -EINVAL;
806 		goto unlock;
807 	}
808 	ec_dbg_ref(ec, "Increase command");
809 	/* following two actions should be kept atomic */
810 	ec->curr = t;
811 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
812 	start_transaction(ec);
813 	spin_unlock_irqrestore(&ec->lock, tmp);
814 
815 	ret = ec_poll(ec);
816 
817 	spin_lock_irqsave(&ec->lock, tmp);
818 	if (t->irq_count == ec_storm_threshold)
819 		acpi_ec_unmask_events(ec);
820 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
821 	ec->curr = NULL;
822 	/* Disable GPE for command processing (IBF=0/OBF=1) */
823 	acpi_ec_complete_request(ec);
824 	ec_dbg_ref(ec, "Decrease command");
825 unlock:
826 	spin_unlock_irqrestore(&ec->lock, tmp);
827 	return ret;
828 }
829 
830 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
831 {
832 	int status;
833 	u32 glk;
834 
835 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
836 		return -EINVAL;
837 	if (t->rdata)
838 		memset(t->rdata, 0, t->rlen);
839 
840 	mutex_lock(&ec->mutex);
841 	if (ec->global_lock) {
842 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
843 		if (ACPI_FAILURE(status)) {
844 			status = -ENODEV;
845 			goto unlock;
846 		}
847 	}
848 
849 	status = acpi_ec_transaction_unlocked(ec, t);
850 
851 	if (ec->global_lock)
852 		acpi_release_global_lock(glk);
853 unlock:
854 	mutex_unlock(&ec->mutex);
855 	return status;
856 }
857 
858 static int acpi_ec_burst_enable(struct acpi_ec *ec)
859 {
860 	u8 d;
861 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
862 				.wdata = NULL, .rdata = &d,
863 				.wlen = 0, .rlen = 1};
864 
865 	return acpi_ec_transaction(ec, &t);
866 }
867 
868 static int acpi_ec_burst_disable(struct acpi_ec *ec)
869 {
870 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
871 				.wdata = NULL, .rdata = NULL,
872 				.wlen = 0, .rlen = 0};
873 
874 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
875 				acpi_ec_transaction(ec, &t) : 0;
876 }
877 
878 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
879 {
880 	int result;
881 	u8 d;
882 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
883 				.wdata = &address, .rdata = &d,
884 				.wlen = 1, .rlen = 1};
885 
886 	result = acpi_ec_transaction(ec, &t);
887 	*data = d;
888 	return result;
889 }
890 
891 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
892 {
893 	u8 wdata[2] = { address, data };
894 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
895 				.wdata = wdata, .rdata = NULL,
896 				.wlen = 2, .rlen = 0};
897 
898 	return acpi_ec_transaction(ec, &t);
899 }
900 
901 int ec_read(u8 addr, u8 *val)
902 {
903 	int err;
904 	u8 temp_data;
905 
906 	if (!first_ec)
907 		return -ENODEV;
908 
909 	err = acpi_ec_read(first_ec, addr, &temp_data);
910 
911 	if (!err) {
912 		*val = temp_data;
913 		return 0;
914 	}
915 	return err;
916 }
917 EXPORT_SYMBOL(ec_read);
918 
919 int ec_write(u8 addr, u8 val)
920 {
921 	int err;
922 
923 	if (!first_ec)
924 		return -ENODEV;
925 
926 	err = acpi_ec_write(first_ec, addr, val);
927 
928 	return err;
929 }
930 EXPORT_SYMBOL(ec_write);
931 
932 int ec_transaction(u8 command,
933 		   const u8 *wdata, unsigned wdata_len,
934 		   u8 *rdata, unsigned rdata_len)
935 {
936 	struct transaction t = {.command = command,
937 				.wdata = wdata, .rdata = rdata,
938 				.wlen = wdata_len, .rlen = rdata_len};
939 
940 	if (!first_ec)
941 		return -ENODEV;
942 
943 	return acpi_ec_transaction(first_ec, &t);
944 }
945 EXPORT_SYMBOL(ec_transaction);
946 
947 /* Get the handle to the EC device */
948 acpi_handle ec_get_handle(void)
949 {
950 	if (!first_ec)
951 		return NULL;
952 	return first_ec->handle;
953 }
954 EXPORT_SYMBOL(ec_get_handle);
955 
956 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
957 {
958 	unsigned long flags;
959 
960 	spin_lock_irqsave(&ec->lock, flags);
961 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
962 		ec_dbg_drv("Starting EC");
963 		/* Enable GPE for event processing (SCI_EVT=1) */
964 		if (!resuming) {
965 			acpi_ec_submit_request(ec);
966 			ec_dbg_ref(ec, "Increase driver");
967 		}
968 		ec_log_drv("EC started");
969 	}
970 	spin_unlock_irqrestore(&ec->lock, flags);
971 }
972 
973 static bool acpi_ec_stopped(struct acpi_ec *ec)
974 {
975 	unsigned long flags;
976 	bool flushed;
977 
978 	spin_lock_irqsave(&ec->lock, flags);
979 	flushed = acpi_ec_flushed(ec);
980 	spin_unlock_irqrestore(&ec->lock, flags);
981 	return flushed;
982 }
983 
984 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
985 {
986 	unsigned long flags;
987 
988 	spin_lock_irqsave(&ec->lock, flags);
989 	if (acpi_ec_started(ec)) {
990 		ec_dbg_drv("Stopping EC");
991 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
992 		spin_unlock_irqrestore(&ec->lock, flags);
993 		wait_event(ec->wait, acpi_ec_stopped(ec));
994 		spin_lock_irqsave(&ec->lock, flags);
995 		/* Disable GPE for event processing (SCI_EVT=1) */
996 		if (!suspending) {
997 			acpi_ec_complete_request(ec);
998 			ec_dbg_ref(ec, "Decrease driver");
999 		} else if (!ec_freeze_events)
1000 			__acpi_ec_disable_event(ec);
1001 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
1002 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1003 		ec_log_drv("EC stopped");
1004 	}
1005 	spin_unlock_irqrestore(&ec->lock, flags);
1006 }
1007 
1008 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1009 {
1010 	unsigned long flags;
1011 
1012 	spin_lock_irqsave(&ec->lock, flags);
1013 	ec->busy_polling = true;
1014 	ec->polling_guard = 0;
1015 	ec_log_drv("interrupt blocked");
1016 	spin_unlock_irqrestore(&ec->lock, flags);
1017 }
1018 
1019 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1020 {
1021 	unsigned long flags;
1022 
1023 	spin_lock_irqsave(&ec->lock, flags);
1024 	ec->busy_polling = ec_busy_polling;
1025 	ec->polling_guard = ec_polling_guard;
1026 	ec_log_drv("interrupt unblocked");
1027 	spin_unlock_irqrestore(&ec->lock, flags);
1028 }
1029 
1030 void acpi_ec_block_transactions(void)
1031 {
1032 	struct acpi_ec *ec = first_ec;
1033 
1034 	if (!ec)
1035 		return;
1036 
1037 	mutex_lock(&ec->mutex);
1038 	/* Prevent transactions from being carried out */
1039 	acpi_ec_stop(ec, true);
1040 	mutex_unlock(&ec->mutex);
1041 }
1042 
1043 void acpi_ec_unblock_transactions(void)
1044 {
1045 	/*
1046 	 * Allow transactions to happen again (this function is called from
1047 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1048 	 */
1049 	if (first_ec)
1050 		acpi_ec_start(first_ec, true);
1051 }
1052 
1053 /* --------------------------------------------------------------------------
1054                                 Event Management
1055    -------------------------------------------------------------------------- */
1056 static struct acpi_ec_query_handler *
1057 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1058 {
1059 	struct acpi_ec_query_handler *handler;
1060 
1061 	mutex_lock(&ec->mutex);
1062 	list_for_each_entry(handler, &ec->list, node) {
1063 		if (value == handler->query_bit) {
1064 			kref_get(&handler->kref);
1065 			mutex_unlock(&ec->mutex);
1066 			return handler;
1067 		}
1068 	}
1069 	mutex_unlock(&ec->mutex);
1070 	return NULL;
1071 }
1072 
1073 static void acpi_ec_query_handler_release(struct kref *kref)
1074 {
1075 	struct acpi_ec_query_handler *handler =
1076 		container_of(kref, struct acpi_ec_query_handler, kref);
1077 
1078 	kfree(handler);
1079 }
1080 
1081 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1082 {
1083 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1084 }
1085 
1086 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1087 			      acpi_handle handle, acpi_ec_query_func func,
1088 			      void *data)
1089 {
1090 	struct acpi_ec_query_handler *handler =
1091 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1092 
1093 	if (!handler)
1094 		return -ENOMEM;
1095 
1096 	handler->query_bit = query_bit;
1097 	handler->handle = handle;
1098 	handler->func = func;
1099 	handler->data = data;
1100 	mutex_lock(&ec->mutex);
1101 	kref_init(&handler->kref);
1102 	list_add(&handler->node, &ec->list);
1103 	mutex_unlock(&ec->mutex);
1104 	return 0;
1105 }
1106 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1107 
1108 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1109 					  bool remove_all, u8 query_bit)
1110 {
1111 	struct acpi_ec_query_handler *handler, *tmp;
1112 	LIST_HEAD(free_list);
1113 
1114 	mutex_lock(&ec->mutex);
1115 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1116 		if (remove_all || query_bit == handler->query_bit) {
1117 			list_del_init(&handler->node);
1118 			list_add(&handler->node, &free_list);
1119 		}
1120 	}
1121 	mutex_unlock(&ec->mutex);
1122 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1123 		acpi_ec_put_query_handler(handler);
1124 }
1125 
1126 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1127 {
1128 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1129 }
1130 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1131 
1132 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1133 {
1134 	struct acpi_ec_query *q;
1135 	struct transaction *t;
1136 
1137 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1138 	if (!q)
1139 		return NULL;
1140 	INIT_WORK(&q->work, acpi_ec_event_processor);
1141 	t = &q->transaction;
1142 	t->command = ACPI_EC_COMMAND_QUERY;
1143 	t->rdata = pval;
1144 	t->rlen = 1;
1145 	return q;
1146 }
1147 
1148 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1149 {
1150 	if (q) {
1151 		if (q->handler)
1152 			acpi_ec_put_query_handler(q->handler);
1153 		kfree(q);
1154 	}
1155 }
1156 
1157 static void acpi_ec_event_processor(struct work_struct *work)
1158 {
1159 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1160 	struct acpi_ec_query_handler *handler = q->handler;
1161 
1162 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1163 	if (handler->func)
1164 		handler->func(handler->data);
1165 	else if (handler->handle)
1166 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1167 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1168 	acpi_ec_delete_query(q);
1169 }
1170 
1171 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1172 {
1173 	u8 value = 0;
1174 	int result;
1175 	struct acpi_ec_query *q;
1176 
1177 	q = acpi_ec_create_query(&value);
1178 	if (!q)
1179 		return -ENOMEM;
1180 
1181 	/*
1182 	 * Query the EC to find out which _Qxx method we need to evaluate.
1183 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1184 	 * bit to be cleared (and thus clearing the interrupt source).
1185 	 */
1186 	result = acpi_ec_transaction(ec, &q->transaction);
1187 	if (!value)
1188 		result = -ENODATA;
1189 	if (result)
1190 		goto err_exit;
1191 
1192 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1193 	if (!q->handler) {
1194 		result = -ENODATA;
1195 		goto err_exit;
1196 	}
1197 
1198 	/*
1199 	 * It is reported that _Qxx are evaluated in a parallel way on
1200 	 * Windows:
1201 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1202 	 *
1203 	 * Put this log entry before schedule_work() in order to make
1204 	 * it appearing before any other log entries occurred during the
1205 	 * work queue execution.
1206 	 */
1207 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1208 	if (!queue_work(ec_query_wq, &q->work)) {
1209 		ec_dbg_evt("Query(0x%02x) overlapped", value);
1210 		result = -EBUSY;
1211 	}
1212 
1213 err_exit:
1214 	if (result)
1215 		acpi_ec_delete_query(q);
1216 	if (data)
1217 		*data = value;
1218 	return result;
1219 }
1220 
1221 static void acpi_ec_check_event(struct acpi_ec *ec)
1222 {
1223 	unsigned long flags;
1224 
1225 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1226 		if (ec_guard(ec)) {
1227 			spin_lock_irqsave(&ec->lock, flags);
1228 			/*
1229 			 * Take care of the SCI_EVT unless no one else is
1230 			 * taking care of it.
1231 			 */
1232 			if (!ec->curr)
1233 				advance_transaction(ec);
1234 			spin_unlock_irqrestore(&ec->lock, flags);
1235 		}
1236 	}
1237 }
1238 
1239 static void acpi_ec_event_handler(struct work_struct *work)
1240 {
1241 	unsigned long flags;
1242 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1243 
1244 	ec_dbg_evt("Event started");
1245 
1246 	spin_lock_irqsave(&ec->lock, flags);
1247 	while (ec->nr_pending_queries) {
1248 		spin_unlock_irqrestore(&ec->lock, flags);
1249 		(void)acpi_ec_query(ec, NULL);
1250 		spin_lock_irqsave(&ec->lock, flags);
1251 		ec->nr_pending_queries--;
1252 		/*
1253 		 * Before exit, make sure that this work item can be
1254 		 * scheduled again. There might be QR_EC failures, leaving
1255 		 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1256 		 * item from being scheduled again.
1257 		 */
1258 		if (!ec->nr_pending_queries) {
1259 			if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1260 			    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1261 				acpi_ec_complete_query(ec);
1262 		}
1263 	}
1264 	spin_unlock_irqrestore(&ec->lock, flags);
1265 
1266 	ec_dbg_evt("Event stopped");
1267 
1268 	acpi_ec_check_event(ec);
1269 }
1270 
1271 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1272 {
1273 	unsigned long flags;
1274 
1275 	spin_lock_irqsave(&ec->lock, flags);
1276 	advance_transaction(ec);
1277 	spin_unlock_irqrestore(&ec->lock, flags);
1278 }
1279 
1280 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1281 			       u32 gpe_number, void *data)
1282 {
1283 	acpi_ec_handle_interrupt(data);
1284 	return ACPI_INTERRUPT_HANDLED;
1285 }
1286 
1287 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1288 {
1289 	acpi_ec_handle_interrupt(data);
1290 	return IRQ_HANDLED;
1291 }
1292 
1293 /* --------------------------------------------------------------------------
1294  *                           Address Space Management
1295  * -------------------------------------------------------------------------- */
1296 
1297 static acpi_status
1298 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1299 		      u32 bits, u64 *value64,
1300 		      void *handler_context, void *region_context)
1301 {
1302 	struct acpi_ec *ec = handler_context;
1303 	int result = 0, i, bytes = bits / 8;
1304 	u8 *value = (u8 *)value64;
1305 
1306 	if ((address > 0xFF) || !value || !handler_context)
1307 		return AE_BAD_PARAMETER;
1308 
1309 	if (function != ACPI_READ && function != ACPI_WRITE)
1310 		return AE_BAD_PARAMETER;
1311 
1312 	if (ec->busy_polling || bits > 8)
1313 		acpi_ec_burst_enable(ec);
1314 
1315 	for (i = 0; i < bytes; ++i, ++address, ++value)
1316 		result = (function == ACPI_READ) ?
1317 			acpi_ec_read(ec, address, value) :
1318 			acpi_ec_write(ec, address, *value);
1319 
1320 	if (ec->busy_polling || bits > 8)
1321 		acpi_ec_burst_disable(ec);
1322 
1323 	switch (result) {
1324 	case -EINVAL:
1325 		return AE_BAD_PARAMETER;
1326 	case -ENODEV:
1327 		return AE_NOT_FOUND;
1328 	case -ETIME:
1329 		return AE_TIME;
1330 	default:
1331 		return AE_OK;
1332 	}
1333 }
1334 
1335 /* --------------------------------------------------------------------------
1336  *                             Driver Interface
1337  * -------------------------------------------------------------------------- */
1338 
1339 static acpi_status
1340 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1341 
1342 static void acpi_ec_free(struct acpi_ec *ec)
1343 {
1344 	if (first_ec == ec)
1345 		first_ec = NULL;
1346 	if (boot_ec == ec)
1347 		boot_ec = NULL;
1348 	kfree(ec);
1349 }
1350 
1351 static struct acpi_ec *acpi_ec_alloc(void)
1352 {
1353 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1354 
1355 	if (!ec)
1356 		return NULL;
1357 	mutex_init(&ec->mutex);
1358 	init_waitqueue_head(&ec->wait);
1359 	INIT_LIST_HEAD(&ec->list);
1360 	spin_lock_init(&ec->lock);
1361 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1362 	ec->timestamp = jiffies;
1363 	ec->busy_polling = true;
1364 	ec->polling_guard = 0;
1365 	ec->gpe = -1;
1366 	ec->irq = -1;
1367 	return ec;
1368 }
1369 
1370 static acpi_status
1371 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1372 			       void *context, void **return_value)
1373 {
1374 	char node_name[5];
1375 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1376 	struct acpi_ec *ec = context;
1377 	int value = 0;
1378 	acpi_status status;
1379 
1380 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1381 
1382 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1383 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1384 	return AE_OK;
1385 }
1386 
1387 static acpi_status
1388 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1389 {
1390 	acpi_status status;
1391 	unsigned long long tmp = 0;
1392 	struct acpi_ec *ec = context;
1393 
1394 	/* clear addr values, ec_parse_io_ports depend on it */
1395 	ec->command_addr = ec->data_addr = 0;
1396 
1397 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1398 				     ec_parse_io_ports, ec);
1399 	if (ACPI_FAILURE(status))
1400 		return status;
1401 	if (ec->data_addr == 0 || ec->command_addr == 0)
1402 		return AE_OK;
1403 
1404 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1405 		/*
1406 		 * Always inherit the GPE number setting from the ECDT
1407 		 * EC.
1408 		 */
1409 		ec->gpe = boot_ec->gpe;
1410 	} else {
1411 		/* Get GPE bit assignment (EC events). */
1412 		/* TODO: Add support for _GPE returning a package */
1413 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1414 		if (ACPI_SUCCESS(status))
1415 			ec->gpe = tmp;
1416 
1417 		/*
1418 		 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1419 		 * platforms which use GpioInt instead of GPE.
1420 		 */
1421 	}
1422 	/* Use the global lock for all EC transactions? */
1423 	tmp = 0;
1424 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1425 	ec->global_lock = tmp;
1426 	ec->handle = handle;
1427 	return AE_CTRL_TERMINATE;
1428 }
1429 
1430 static void install_gpe_event_handler(struct acpi_ec *ec)
1431 {
1432 	acpi_status status =
1433 		acpi_install_gpe_raw_handler(NULL, ec->gpe,
1434 					     ACPI_GPE_EDGE_TRIGGERED,
1435 					     &acpi_ec_gpe_handler,
1436 					     ec);
1437 	if (ACPI_SUCCESS(status)) {
1438 		/* This is not fatal as we can poll EC events */
1439 		set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1440 		acpi_ec_leave_noirq(ec);
1441 		if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1442 		    ec->reference_count >= 1)
1443 			acpi_ec_enable_gpe(ec, true);
1444 	}
1445 }
1446 
1447 /* ACPI reduced hardware platforms use a GpioInt specified in _CRS. */
1448 static int install_gpio_irq_event_handler(struct acpi_ec *ec,
1449 					  struct acpi_device *device)
1450 {
1451 	int irq = acpi_dev_gpio_irq_get(device, 0);
1452 	int ret;
1453 
1454 	if (irq < 0)
1455 		return irq;
1456 
1457 	ret = request_irq(irq, acpi_ec_irq_handler, IRQF_SHARED,
1458 			  "ACPI EC", ec);
1459 
1460 	/*
1461 	 * Unlike the GPE case, we treat errors here as fatal, we'll only
1462 	 * implement GPIO polling if we find a case that needs it.
1463 	 */
1464 	if (ret < 0)
1465 		return ret;
1466 
1467 	ec->irq = irq;
1468 	set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1469 	acpi_ec_leave_noirq(ec);
1470 
1471 	return 0;
1472 }
1473 
1474 /*
1475  * Note: This function returns an error code only when the address space
1476  *       handler is not installed, which means "not able to handle
1477  *       transactions".
1478  */
1479 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1480 			       bool handle_events)
1481 {
1482 	acpi_status status;
1483 
1484 	acpi_ec_start(ec, false);
1485 
1486 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1487 		acpi_ec_enter_noirq(ec);
1488 		status = acpi_install_address_space_handler(ec->handle,
1489 							    ACPI_ADR_SPACE_EC,
1490 							    &acpi_ec_space_handler,
1491 							    NULL, ec);
1492 		if (ACPI_FAILURE(status)) {
1493 			if (status == AE_NOT_FOUND) {
1494 				/*
1495 				 * Maybe OS fails in evaluating the _REG
1496 				 * object. The AE_NOT_FOUND error will be
1497 				 * ignored and OS * continue to initialize
1498 				 * EC.
1499 				 */
1500 				pr_err("Fail in evaluating the _REG object"
1501 					" of EC device. Broken bios is suspected.\n");
1502 			} else {
1503 				acpi_ec_stop(ec, false);
1504 				return -ENODEV;
1505 			}
1506 		}
1507 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1508 	}
1509 
1510 	if (!handle_events)
1511 		return 0;
1512 
1513 	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1514 		/* Find and register all query methods */
1515 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1516 				    acpi_ec_register_query_methods,
1517 				    NULL, ec, NULL);
1518 		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1519 	}
1520 	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1521 		if (ec->gpe >= 0) {
1522 			install_gpe_event_handler(ec);
1523 		} else if (device) {
1524 			int ret = install_gpio_irq_event_handler(ec, device);
1525 
1526 			if (ret)
1527 				return ret;
1528 		} else { /* No GPE and no GpioInt? */
1529 			return -ENODEV;
1530 		}
1531 	}
1532 	/* EC is fully operational, allow queries */
1533 	acpi_ec_enable_event(ec);
1534 
1535 	return 0;
1536 }
1537 
1538 static void ec_remove_handlers(struct acpi_ec *ec)
1539 {
1540 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1541 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1542 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1543 			pr_err("failed to remove space handler\n");
1544 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1545 	}
1546 
1547 	/*
1548 	 * Stops handling the EC transactions after removing the operation
1549 	 * region handler. This is required because _REG(DISCONNECT)
1550 	 * invoked during the removal can result in new EC transactions.
1551 	 *
1552 	 * Flushes the EC requests and thus disables the GPE before
1553 	 * removing the GPE handler. This is required by the current ACPICA
1554 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1555 	 * it is indicated but there is no way to handle it. So the drivers
1556 	 * must disable the GPEs prior to removing the GPE handlers.
1557 	 */
1558 	acpi_ec_stop(ec, false);
1559 
1560 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1561 		if (ec->gpe >= 0 &&
1562 		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1563 				 &acpi_ec_gpe_handler)))
1564 			pr_err("failed to remove gpe handler\n");
1565 
1566 		if (ec->irq >= 0)
1567 			free_irq(ec->irq, ec);
1568 
1569 		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1570 	}
1571 	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1572 		acpi_ec_remove_query_handlers(ec, true, 0);
1573 		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1574 	}
1575 }
1576 
1577 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device,
1578 			 bool handle_events)
1579 {
1580 	int ret;
1581 
1582 	ret = ec_install_handlers(ec, device, handle_events);
1583 	if (ret)
1584 		return ret;
1585 
1586 	/* First EC capable of handling transactions */
1587 	if (!first_ec) {
1588 		first_ec = ec;
1589 		acpi_handle_info(first_ec->handle, "Used as first EC\n");
1590 	}
1591 
1592 	acpi_handle_info(ec->handle,
1593 			 "GPE=0x%x, IRQ=%d, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1594 			 ec->gpe, ec->irq, ec->command_addr, ec->data_addr);
1595 	return ret;
1596 }
1597 
1598 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1599 {
1600 	struct acpi_table_ecdt *ecdt_ptr;
1601 	acpi_status status;
1602 	acpi_handle handle;
1603 
1604 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1605 				(struct acpi_table_header **)&ecdt_ptr);
1606 	if (ACPI_FAILURE(status))
1607 		return false;
1608 
1609 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1610 	if (ACPI_FAILURE(status))
1611 		return false;
1612 
1613 	*phandle = handle;
1614 	return true;
1615 }
1616 
1617 static int acpi_ec_add(struct acpi_device *device)
1618 {
1619 	struct acpi_ec *ec = NULL;
1620 	bool dep_update = true;
1621 	acpi_status status;
1622 	int ret;
1623 
1624 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1625 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1626 
1627 	if (!strcmp(acpi_device_hid(device), ACPI_ECDT_HID)) {
1628 		boot_ec_is_ecdt = true;
1629 		ec = boot_ec;
1630 		dep_update = false;
1631 	} else {
1632 		ec = acpi_ec_alloc();
1633 		if (!ec)
1634 			return -ENOMEM;
1635 
1636 		status = ec_parse_device(device->handle, 0, ec, NULL);
1637 		if (status != AE_CTRL_TERMINATE) {
1638 			ret = -EINVAL;
1639 			goto err_alloc;
1640 		}
1641 
1642 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1643 		    ec->data_addr == boot_ec->data_addr) {
1644 			boot_ec_is_ecdt = false;
1645 			/*
1646 			 * Trust PNP0C09 namespace location rather than
1647 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1648 			 * because of ASUS quirks, so do not change
1649 			 * boot_ec->gpe to ec->gpe.
1650 			 */
1651 			boot_ec->handle = ec->handle;
1652 			acpi_handle_debug(ec->handle, "duplicated.\n");
1653 			acpi_ec_free(ec);
1654 			ec = boot_ec;
1655 		}
1656 	}
1657 
1658 	ret = acpi_ec_setup(ec, device, true);
1659 	if (ret)
1660 		goto err_query;
1661 
1662 	if (ec == boot_ec)
1663 		acpi_handle_info(boot_ec->handle,
1664 				 "Boot %s EC used to handle transactions and events\n",
1665 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1666 
1667 	device->driver_data = ec;
1668 
1669 	ret = !!request_region(ec->data_addr, 1, "EC data");
1670 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1671 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1672 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1673 
1674 	if (dep_update) {
1675 		/* Reprobe devices depending on the EC */
1676 		acpi_walk_dep_device_list(ec->handle);
1677 	}
1678 	acpi_handle_debug(ec->handle, "enumerated.\n");
1679 	return 0;
1680 
1681 err_query:
1682 	if (ec != boot_ec)
1683 		acpi_ec_remove_query_handlers(ec, true, 0);
1684 err_alloc:
1685 	if (ec != boot_ec)
1686 		acpi_ec_free(ec);
1687 	return ret;
1688 }
1689 
1690 static int acpi_ec_remove(struct acpi_device *device)
1691 {
1692 	struct acpi_ec *ec;
1693 
1694 	if (!device)
1695 		return -EINVAL;
1696 
1697 	ec = acpi_driver_data(device);
1698 	release_region(ec->data_addr, 1);
1699 	release_region(ec->command_addr, 1);
1700 	device->driver_data = NULL;
1701 	if (ec != boot_ec) {
1702 		ec_remove_handlers(ec);
1703 		acpi_ec_free(ec);
1704 	}
1705 	return 0;
1706 }
1707 
1708 static acpi_status
1709 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1710 {
1711 	struct acpi_ec *ec = context;
1712 
1713 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1714 		return AE_OK;
1715 
1716 	/*
1717 	 * The first address region returned is the data port, and
1718 	 * the second address region returned is the status/command
1719 	 * port.
1720 	 */
1721 	if (ec->data_addr == 0)
1722 		ec->data_addr = resource->data.io.minimum;
1723 	else if (ec->command_addr == 0)
1724 		ec->command_addr = resource->data.io.minimum;
1725 	else
1726 		return AE_CTRL_TERMINATE;
1727 
1728 	return AE_OK;
1729 }
1730 
1731 static const struct acpi_device_id ec_device_ids[] = {
1732 	{"PNP0C09", 0},
1733 	{ACPI_ECDT_HID, 0},
1734 	{"", 0},
1735 };
1736 
1737 /*
1738  * This function is not Windows-compatible as Windows never enumerates the
1739  * namespace EC before the main ACPI device enumeration process. It is
1740  * retained for historical reason and will be deprecated in the future.
1741  */
1742 void __init acpi_ec_dsdt_probe(void)
1743 {
1744 	struct acpi_ec *ec;
1745 	acpi_status status;
1746 	int ret;
1747 
1748 	/*
1749 	 * If a platform has ECDT, there is no need to proceed as the
1750 	 * following probe is not a part of the ACPI device enumeration,
1751 	 * executing _STA is not safe, and thus this probe may risk of
1752 	 * picking up an invalid EC device.
1753 	 */
1754 	if (boot_ec)
1755 		return;
1756 
1757 	ec = acpi_ec_alloc();
1758 	if (!ec)
1759 		return;
1760 
1761 	/*
1762 	 * At this point, the namespace is initialized, so start to find
1763 	 * the namespace objects.
1764 	 */
1765 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1766 	if (ACPI_FAILURE(status) || !ec->handle) {
1767 		acpi_ec_free(ec);
1768 		return;
1769 	}
1770 
1771 	/*
1772 	 * When the DSDT EC is available, always re-configure boot EC to
1773 	 * have _REG evaluated. _REG can only be evaluated after the
1774 	 * namespace initialization.
1775 	 * At this point, the GPE is not fully initialized, so do not to
1776 	 * handle the events.
1777 	 */
1778 	ret = acpi_ec_setup(ec, NULL, false);
1779 	if (ret) {
1780 		acpi_ec_free(ec);
1781 		return;
1782 	}
1783 
1784 	boot_ec = ec;
1785 
1786 	acpi_handle_info(ec->handle,
1787 			 "Boot DSDT EC used to handle transactions\n");
1788 }
1789 
1790 /*
1791  * If the DSDT EC is not functioning, we still need to prepare a fully
1792  * functioning ECDT EC first in order to handle the events.
1793  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1794  */
1795 static int __init acpi_ec_ecdt_start(void)
1796 {
1797 	acpi_handle handle;
1798 
1799 	if (!boot_ec)
1800 		return -ENODEV;
1801 	/* In case acpi_ec_ecdt_start() is called after acpi_ec_add() */
1802 	if (!boot_ec_is_ecdt)
1803 		return -ENODEV;
1804 
1805 	/*
1806 	 * At this point, the namespace and the GPE is initialized, so
1807 	 * start to find the namespace objects and handle the events.
1808 	 *
1809 	 * Note: ec->handle can be valid if this function is called after
1810 	 * acpi_ec_add(), hence the fast path.
1811 	 */
1812 	if (boot_ec->handle == ACPI_ROOT_OBJECT) {
1813 		if (!acpi_ec_ecdt_get_handle(&handle))
1814 			return -ENODEV;
1815 		boot_ec->handle = handle;
1816 	}
1817 
1818 	/* Register to ACPI bus with PM ops attached */
1819 	return acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1820 }
1821 
1822 #if 0
1823 /*
1824  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1825  * set, for which case, we complete the QR_EC without issuing it to the
1826  * firmware.
1827  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1828  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1829  */
1830 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1831 {
1832 	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1833 	EC_FLAGS_QUERY_HANDSHAKE = 1;
1834 	return 0;
1835 }
1836 #endif
1837 
1838 /*
1839  * On some hardware it is necessary to clear events accumulated by the EC during
1840  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1841  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1842  *
1843  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1844  *
1845  * Ideally, the EC should also be instructed NOT to accumulate events during
1846  * sleep (which Windows seems to do somehow), but the interface to control this
1847  * behaviour is not known at this time.
1848  *
1849  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1850  * however it is very likely that other Samsung models are affected.
1851  *
1852  * On systems which don't accumulate _Q events during sleep, this extra check
1853  * should be harmless.
1854  */
1855 static int ec_clear_on_resume(const struct dmi_system_id *id)
1856 {
1857 	pr_debug("Detected system needing EC poll on resume.\n");
1858 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1859 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1860 	return 0;
1861 }
1862 
1863 /*
1864  * Some ECDTs contain wrong register addresses.
1865  * MSI MS-171F
1866  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1867  */
1868 static int ec_correct_ecdt(const struct dmi_system_id *id)
1869 {
1870 	pr_debug("Detected system needing ECDT address correction.\n");
1871 	EC_FLAGS_CORRECT_ECDT = 1;
1872 	return 0;
1873 }
1874 
1875 /*
1876  * Some DSDTs contain wrong GPE setting.
1877  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1878  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1879  */
1880 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1881 {
1882 	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1883 	EC_FLAGS_IGNORE_DSDT_GPE = 1;
1884 	return 0;
1885 }
1886 
1887 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1888 	{
1889 	ec_correct_ecdt, "MSI MS-171F", {
1890 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1891 	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1892 	{
1893 	ec_honor_ecdt_gpe, "ASUS FX502VD", {
1894 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1895 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1896 	{
1897 	ec_honor_ecdt_gpe, "ASUS FX502VE", {
1898 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1899 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1900 	{
1901 	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1902 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1903 	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1904 	{
1905 	ec_honor_ecdt_gpe, "ASUS X550VXK", {
1906 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1907 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1908 	{
1909 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1910 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1911 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1912 	{
1913 	ec_clear_on_resume, "Samsung hardware", {
1914 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1915 	{},
1916 };
1917 
1918 void __init acpi_ec_ecdt_probe(void)
1919 {
1920 	struct acpi_table_ecdt *ecdt_ptr;
1921 	struct acpi_ec *ec;
1922 	acpi_status status;
1923 	int ret;
1924 
1925 	/* Generate a boot ec context. */
1926 	dmi_check_system(ec_dmi_table);
1927 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1928 				(struct acpi_table_header **)&ecdt_ptr);
1929 	if (ACPI_FAILURE(status))
1930 		return;
1931 
1932 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1933 		/*
1934 		 * Asus X50GL:
1935 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1936 		 */
1937 		return;
1938 	}
1939 
1940 	ec = acpi_ec_alloc();
1941 	if (!ec)
1942 		return;
1943 
1944 	if (EC_FLAGS_CORRECT_ECDT) {
1945 		ec->command_addr = ecdt_ptr->data.address;
1946 		ec->data_addr = ecdt_ptr->control.address;
1947 	} else {
1948 		ec->command_addr = ecdt_ptr->control.address;
1949 		ec->data_addr = ecdt_ptr->data.address;
1950 	}
1951 
1952 	/*
1953 	 * Ignore the GPE value on Reduced Hardware platforms.
1954 	 * Some products have this set to an erroneous value.
1955 	 */
1956 	if (!acpi_gbl_reduced_hardware)
1957 		ec->gpe = ecdt_ptr->gpe;
1958 
1959 	ec->handle = ACPI_ROOT_OBJECT;
1960 
1961 	/*
1962 	 * At this point, the namespace is not initialized, so do not find
1963 	 * the namespace objects, or handle the events.
1964 	 */
1965 	ret = acpi_ec_setup(ec, NULL, false);
1966 	if (ret) {
1967 		acpi_ec_free(ec);
1968 		return;
1969 	}
1970 
1971 	boot_ec = ec;
1972 	boot_ec_is_ecdt = true;
1973 
1974 	pr_info("Boot ECDT EC used to handle transactions\n");
1975 }
1976 
1977 #ifdef CONFIG_PM_SLEEP
1978 static int acpi_ec_suspend(struct device *dev)
1979 {
1980 	struct acpi_ec *ec =
1981 		acpi_driver_data(to_acpi_device(dev));
1982 
1983 	if (!pm_suspend_no_platform() && ec_freeze_events)
1984 		acpi_ec_disable_event(ec);
1985 	return 0;
1986 }
1987 
1988 static int acpi_ec_suspend_noirq(struct device *dev)
1989 {
1990 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1991 
1992 	/*
1993 	 * The SCI handler doesn't run at this point, so the GPE can be
1994 	 * masked at the low level without side effects.
1995 	 */
1996 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1997 	    ec->gpe >= 0 && ec->reference_count >= 1)
1998 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1999 
2000 	acpi_ec_enter_noirq(ec);
2001 
2002 	return 0;
2003 }
2004 
2005 static int acpi_ec_resume_noirq(struct device *dev)
2006 {
2007 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2008 
2009 	acpi_ec_leave_noirq(ec);
2010 
2011 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2012 	    ec->gpe >= 0 && ec->reference_count >= 1)
2013 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2014 
2015 	return 0;
2016 }
2017 
2018 static int acpi_ec_resume(struct device *dev)
2019 {
2020 	struct acpi_ec *ec =
2021 		acpi_driver_data(to_acpi_device(dev));
2022 
2023 	acpi_ec_enable_event(ec);
2024 	return 0;
2025 }
2026 
2027 void acpi_ec_mark_gpe_for_wake(void)
2028 {
2029 	if (first_ec && !ec_no_wakeup)
2030 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2031 }
2032 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2033 
2034 void acpi_ec_set_gpe_wake_mask(u8 action)
2035 {
2036 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2037 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2038 }
2039 
2040 bool acpi_ec_dispatch_gpe(void)
2041 {
2042 	u32 ret;
2043 
2044 	if (!first_ec)
2045 		return false;
2046 
2047 	ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2048 	if (ret == ACPI_INTERRUPT_HANDLED) {
2049 		pm_pr_dbg("EC GPE dispatched\n");
2050 		return true;
2051 	}
2052 	return false;
2053 }
2054 #endif /* CONFIG_PM_SLEEP */
2055 
2056 static const struct dev_pm_ops acpi_ec_pm = {
2057 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2058 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2059 };
2060 
2061 static int param_set_event_clearing(const char *val,
2062 				    const struct kernel_param *kp)
2063 {
2064 	int result = 0;
2065 
2066 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2067 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2068 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2069 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2070 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2071 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2072 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2073 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2074 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2075 	} else
2076 		result = -EINVAL;
2077 	return result;
2078 }
2079 
2080 static int param_get_event_clearing(char *buffer,
2081 				    const struct kernel_param *kp)
2082 {
2083 	switch (ec_event_clearing) {
2084 	case ACPI_EC_EVT_TIMING_STATUS:
2085 		return sprintf(buffer, "status");
2086 	case ACPI_EC_EVT_TIMING_QUERY:
2087 		return sprintf(buffer, "query");
2088 	case ACPI_EC_EVT_TIMING_EVENT:
2089 		return sprintf(buffer, "event");
2090 	default:
2091 		return sprintf(buffer, "invalid");
2092 	}
2093 	return 0;
2094 }
2095 
2096 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2097 		  NULL, 0644);
2098 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2099 
2100 static struct acpi_driver acpi_ec_driver = {
2101 	.name = "ec",
2102 	.class = ACPI_EC_CLASS,
2103 	.ids = ec_device_ids,
2104 	.ops = {
2105 		.add = acpi_ec_add,
2106 		.remove = acpi_ec_remove,
2107 		},
2108 	.drv.pm = &acpi_ec_pm,
2109 };
2110 
2111 static void acpi_ec_destroy_workqueues(void)
2112 {
2113 	if (ec_wq) {
2114 		destroy_workqueue(ec_wq);
2115 		ec_wq = NULL;
2116 	}
2117 	if (ec_query_wq) {
2118 		destroy_workqueue(ec_query_wq);
2119 		ec_query_wq = NULL;
2120 	}
2121 }
2122 
2123 static int acpi_ec_init_workqueues(void)
2124 {
2125 	if (!ec_wq)
2126 		ec_wq = alloc_ordered_workqueue("kec", 0);
2127 
2128 	if (!ec_query_wq)
2129 		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2130 
2131 	if (!ec_wq || !ec_query_wq) {
2132 		acpi_ec_destroy_workqueues();
2133 		return -ENODEV;
2134 	}
2135 	return 0;
2136 }
2137 
2138 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2139 	{
2140 		.ident = "Thinkpad X1 Carbon 6th",
2141 		.matches = {
2142 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2143 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2144 		},
2145 	},
2146 	{
2147 		.ident = "ThinkPad X1 Carbon 6th",
2148 		.matches = {
2149 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2150 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2151 		},
2152 	},
2153 	{
2154 		.ident = "ThinkPad X1 Yoga 3rd",
2155 		.matches = {
2156 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2157 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2158 		},
2159 	},
2160 	{ },
2161 };
2162 
2163 int __init acpi_ec_init(void)
2164 {
2165 	int result;
2166 	int ecdt_fail, dsdt_fail;
2167 
2168 	result = acpi_ec_init_workqueues();
2169 	if (result)
2170 		return result;
2171 
2172 	/*
2173 	 * Disable EC wakeup on following systems to prevent periodic
2174 	 * wakeup from EC GPE.
2175 	 */
2176 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2177 		ec_no_wakeup = true;
2178 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2179 	}
2180 
2181 	/* Drivers must be started after acpi_ec_query_init() */
2182 	dsdt_fail = acpi_bus_register_driver(&acpi_ec_driver);
2183 	/*
2184 	 * Register ECDT to ACPI bus only when PNP0C09 probe fails. This is
2185 	 * useful for platforms (confirmed on ASUS X550ZE) with valid ECDT
2186 	 * settings but invalid DSDT settings.
2187 	 * https://bugzilla.kernel.org/show_bug.cgi?id=196847
2188 	 */
2189 	ecdt_fail = acpi_ec_ecdt_start();
2190 	return ecdt_fail && dsdt_fail ? -ENODEV : 0;
2191 }
2192 
2193 /* EC driver currently not unloadable */
2194 #if 0
2195 static void __exit acpi_ec_exit(void)
2196 {
2197 
2198 	acpi_bus_unregister_driver(&acpi_ec_driver);
2199 	acpi_ec_destroy_workqueues();
2200 }
2201 #endif	/* 0 */
2202