xref: /linux/drivers/acpi/ec.c (revision 11b3125073d16929403d3aa7b2ae6a482060a937)
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 
38 /* EC status register */
39 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
40 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
41 #define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
42 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
43 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
44 
45 /*
46  * The SCI_EVT clearing timing is not defined by the ACPI specification.
47  * This leads to lots of practical timing issues for the host EC driver.
48  * The following variations are defined (from the target EC firmware's
49  * perspective):
50  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
51  *         target can clear SCI_EVT at any time so long as the host can see
52  *         the indication by reading the status register (EC_SC). So the
53  *         host should re-check SCI_EVT after the first time the SCI_EVT
54  *         indication is seen, which is the same time the query request
55  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
56  *         at any later time could indicate another event. Normally such
57  *         kind of EC firmware has implemented an event queue and will
58  *         return 0x00 to indicate "no outstanding event".
59  * QUERY: After seeing the query request (QR_EC) written to the command
60  *        register (EC_CMD) by the host and having prepared the responding
61  *        event value in the data register (EC_DATA), the target can safely
62  *        clear SCI_EVT because the target can confirm that the current
63  *        event is being handled by the host. The host then should check
64  *        SCI_EVT right after reading the event response from the data
65  *        register (EC_DATA).
66  * EVENT: After seeing the event response read from the data register
67  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
68  *        target requires time to notice the change in the data register
69  *        (EC_DATA), the host may be required to wait additional guarding
70  *        time before checking the SCI_EVT again. Such guarding may not be
71  *        necessary if the host is notified via another IRQ.
72  */
73 #define ACPI_EC_EVT_TIMING_STATUS	0x00
74 #define ACPI_EC_EVT_TIMING_QUERY	0x01
75 #define ACPI_EC_EVT_TIMING_EVENT	0x02
76 
77 /* EC commands */
78 enum ec_command {
79 	ACPI_EC_COMMAND_READ = 0x80,
80 	ACPI_EC_COMMAND_WRITE = 0x81,
81 	ACPI_EC_BURST_ENABLE = 0x82,
82 	ACPI_EC_BURST_DISABLE = 0x83,
83 	ACPI_EC_COMMAND_QUERY = 0x84,
84 };
85 
86 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
87 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
88 #define ACPI_EC_UDELAY_POLL	550	/* Wait 1ms for EC transaction polling */
89 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
90 					 * when trying to clear the EC */
91 #define ACPI_EC_MAX_QUERIES	16	/* Maximum number of parallel queries */
92 
93 enum {
94 	EC_FLAGS_QUERY_ENABLED,		/* Query is enabled */
95 	EC_FLAGS_EVENT_HANDLER_INSTALLED,	/* Event handler installed */
96 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
97 	EC_FLAGS_EC_REG_CALLED,		/* OpReg ACPI _REG method called */
98 	EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
99 	EC_FLAGS_STARTED,		/* Driver is started */
100 	EC_FLAGS_STOPPED,		/* Driver is stopped */
101 	EC_FLAGS_EVENTS_MASKED,		/* Events masked */
102 };
103 
104 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
105 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
106 
107 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
108 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
109 module_param(ec_delay, uint, 0644);
110 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
111 
112 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
113 module_param(ec_max_queries, uint, 0644);
114 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
115 
116 static bool ec_busy_polling __read_mostly;
117 module_param(ec_busy_polling, bool, 0644);
118 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
119 
120 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
121 module_param(ec_polling_guard, uint, 0644);
122 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
123 
124 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
125 
126 /*
127  * If the number of false interrupts per one transaction exceeds
128  * this threshold, will think there is a GPE storm happened and
129  * will disable the GPE for normal transaction.
130  */
131 static unsigned int ec_storm_threshold  __read_mostly = 8;
132 module_param(ec_storm_threshold, uint, 0644);
133 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
134 
135 static bool ec_freeze_events __read_mostly;
136 module_param(ec_freeze_events, bool, 0644);
137 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
138 
139 static bool ec_no_wakeup __read_mostly;
140 module_param(ec_no_wakeup, bool, 0644);
141 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
142 
143 struct acpi_ec_query_handler {
144 	struct list_head node;
145 	acpi_ec_query_func func;
146 	acpi_handle handle;
147 	void *data;
148 	u8 query_bit;
149 	struct kref kref;
150 };
151 
152 struct transaction {
153 	const u8 *wdata;
154 	u8 *rdata;
155 	unsigned short irq_count;
156 	u8 command;
157 	u8 wi;
158 	u8 ri;
159 	u8 wlen;
160 	u8 rlen;
161 	u8 flags;
162 };
163 
164 struct acpi_ec_query {
165 	struct transaction transaction;
166 	struct work_struct work;
167 	struct acpi_ec_query_handler *handler;
168 	struct acpi_ec *ec;
169 };
170 
171 static int acpi_ec_submit_query(struct acpi_ec *ec);
172 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
173 static void acpi_ec_event_handler(struct work_struct *work);
174 
175 struct acpi_ec *first_ec;
176 EXPORT_SYMBOL(first_ec);
177 
178 static struct acpi_ec *boot_ec;
179 static bool boot_ec_is_ecdt;
180 static struct workqueue_struct *ec_wq;
181 static struct workqueue_struct *ec_query_wq;
182 
183 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
184 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
185 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
186 
187 /* --------------------------------------------------------------------------
188  *                           Logging/Debugging
189  * -------------------------------------------------------------------------- */
190 
191 /*
192  * Splitters used by the developers to track the boundary of the EC
193  * handling processes.
194  */
195 #ifdef DEBUG
196 #define EC_DBG_SEP	" "
197 #define EC_DBG_DRV	"+++++"
198 #define EC_DBG_STM	"====="
199 #define EC_DBG_REQ	"*****"
200 #define EC_DBG_EVT	"#####"
201 #else
202 #define EC_DBG_SEP	""
203 #define EC_DBG_DRV
204 #define EC_DBG_STM
205 #define EC_DBG_REQ
206 #define EC_DBG_EVT
207 #endif
208 
209 #define ec_log_raw(fmt, ...) \
210 	pr_info(fmt "\n", ##__VA_ARGS__)
211 #define ec_dbg_raw(fmt, ...) \
212 	pr_debug(fmt "\n", ##__VA_ARGS__)
213 #define ec_log(filter, fmt, ...) \
214 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
215 #define ec_dbg(filter, fmt, ...) \
216 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
217 
218 #define ec_log_drv(fmt, ...) \
219 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
220 #define ec_dbg_drv(fmt, ...) \
221 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
222 #define ec_dbg_stm(fmt, ...) \
223 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
224 #define ec_dbg_req(fmt, ...) \
225 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
226 #define ec_dbg_evt(fmt, ...) \
227 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
228 #define ec_dbg_ref(ec, fmt, ...) \
229 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
230 
231 /* --------------------------------------------------------------------------
232  *                           Device Flags
233  * -------------------------------------------------------------------------- */
234 
acpi_ec_started(struct acpi_ec * ec)235 static bool acpi_ec_started(struct acpi_ec *ec)
236 {
237 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
238 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
239 }
240 
acpi_ec_event_enabled(struct acpi_ec * ec)241 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
242 {
243 	/*
244 	 * There is an OSPM early stage logic. During the early stages
245 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
246 	 * the EC transactions are allowed to be performed.
247 	 */
248 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
249 		return false;
250 	/*
251 	 * However, disabling the event handling is experimental for late
252 	 * stage (suspend), and is controlled by the boot parameter of
253 	 * "ec_freeze_events":
254 	 * 1. true:  The EC event handling is disabled before entering
255 	 *           the noirq stage.
256 	 * 2. false: The EC event handling is automatically disabled as
257 	 *           soon as the EC driver is stopped.
258 	 */
259 	if (ec_freeze_events)
260 		return acpi_ec_started(ec);
261 	else
262 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
263 }
264 
acpi_ec_flushed(struct acpi_ec * ec)265 static bool acpi_ec_flushed(struct acpi_ec *ec)
266 {
267 	return ec->reference_count == 1;
268 }
269 
270 /* --------------------------------------------------------------------------
271  *                           EC Registers
272  * -------------------------------------------------------------------------- */
273 
acpi_ec_read_status(struct acpi_ec * ec)274 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
275 {
276 	u8 x = inb(ec->command_addr);
277 
278 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
279 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
280 		   x,
281 		   !!(x & ACPI_EC_FLAG_SCI),
282 		   !!(x & ACPI_EC_FLAG_BURST),
283 		   !!(x & ACPI_EC_FLAG_CMD),
284 		   !!(x & ACPI_EC_FLAG_IBF),
285 		   !!(x & ACPI_EC_FLAG_OBF));
286 	return x;
287 }
288 
acpi_ec_read_data(struct acpi_ec * ec)289 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
290 {
291 	u8 x = inb(ec->data_addr);
292 
293 	ec->timestamp = jiffies;
294 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
295 	return x;
296 }
297 
acpi_ec_write_cmd(struct acpi_ec * ec,u8 command)298 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
299 {
300 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
301 	outb(command, ec->command_addr);
302 	ec->timestamp = jiffies;
303 }
304 
acpi_ec_write_data(struct acpi_ec * ec,u8 data)305 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
306 {
307 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
308 	outb(data, ec->data_addr);
309 	ec->timestamp = jiffies;
310 }
311 
312 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
acpi_ec_cmd_string(u8 cmd)313 static const char *acpi_ec_cmd_string(u8 cmd)
314 {
315 	switch (cmd) {
316 	case 0x80:
317 		return "RD_EC";
318 	case 0x81:
319 		return "WR_EC";
320 	case 0x82:
321 		return "BE_EC";
322 	case 0x83:
323 		return "BD_EC";
324 	case 0x84:
325 		return "QR_EC";
326 	}
327 	return "UNKNOWN";
328 }
329 #else
330 #define acpi_ec_cmd_string(cmd)		"UNDEF"
331 #endif
332 
333 /* --------------------------------------------------------------------------
334  *                           GPE Registers
335  * -------------------------------------------------------------------------- */
336 
acpi_ec_gpe_status_set(struct acpi_ec * ec)337 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
338 {
339 	acpi_event_status gpe_status = 0;
340 
341 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
342 	return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
343 }
344 
acpi_ec_enable_gpe(struct acpi_ec * ec,bool open)345 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
346 {
347 	if (open)
348 		acpi_enable_gpe(NULL, ec->gpe);
349 	else {
350 		BUG_ON(ec->reference_count < 1);
351 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
352 	}
353 	if (acpi_ec_gpe_status_set(ec)) {
354 		/*
355 		 * On some platforms, EN=1 writes cannot trigger GPE. So
356 		 * software need to manually trigger a pseudo GPE event on
357 		 * EN=1 writes.
358 		 */
359 		ec_dbg_raw("Polling quirk");
360 		advance_transaction(ec, false);
361 	}
362 }
363 
acpi_ec_disable_gpe(struct acpi_ec * ec,bool close)364 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
365 {
366 	if (close)
367 		acpi_disable_gpe(NULL, ec->gpe);
368 	else {
369 		BUG_ON(ec->reference_count < 1);
370 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
371 	}
372 }
373 
374 /* --------------------------------------------------------------------------
375  *                           Transaction Management
376  * -------------------------------------------------------------------------- */
377 
acpi_ec_submit_request(struct acpi_ec * ec)378 static void acpi_ec_submit_request(struct acpi_ec *ec)
379 {
380 	ec->reference_count++;
381 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
382 	    ec->gpe >= 0 && ec->reference_count == 1)
383 		acpi_ec_enable_gpe(ec, true);
384 }
385 
acpi_ec_complete_request(struct acpi_ec * ec)386 static void acpi_ec_complete_request(struct acpi_ec *ec)
387 {
388 	bool flushed = false;
389 
390 	ec->reference_count--;
391 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
392 	    ec->gpe >= 0 && ec->reference_count == 0)
393 		acpi_ec_disable_gpe(ec, true);
394 	flushed = acpi_ec_flushed(ec);
395 	if (flushed)
396 		wake_up(&ec->wait);
397 }
398 
acpi_ec_mask_events(struct acpi_ec * ec)399 static void acpi_ec_mask_events(struct acpi_ec *ec)
400 {
401 	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
402 		if (ec->gpe >= 0)
403 			acpi_ec_disable_gpe(ec, false);
404 		else
405 			disable_irq_nosync(ec->irq);
406 
407 		ec_dbg_drv("Polling enabled");
408 		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
409 	}
410 }
411 
acpi_ec_unmask_events(struct acpi_ec * ec)412 static void acpi_ec_unmask_events(struct acpi_ec *ec)
413 {
414 	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
415 		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
416 		if (ec->gpe >= 0)
417 			acpi_ec_enable_gpe(ec, false);
418 		else
419 			enable_irq(ec->irq);
420 
421 		ec_dbg_drv("Polling disabled");
422 	}
423 }
424 
425 /*
426  * acpi_ec_submit_flushable_request() - Increase the reference count unless
427  *                                      the flush operation is not in
428  *                                      progress
429  * @ec: the EC device
430  *
431  * This function must be used before taking a new action that should hold
432  * the reference count.  If this function returns false, then the action
433  * must be discarded or it will prevent the flush operation from being
434  * completed.
435  */
acpi_ec_submit_flushable_request(struct acpi_ec * ec)436 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
437 {
438 	if (!acpi_ec_started(ec))
439 		return false;
440 	acpi_ec_submit_request(ec);
441 	return true;
442 }
443 
acpi_ec_submit_event(struct acpi_ec * ec)444 static void acpi_ec_submit_event(struct acpi_ec *ec)
445 {
446 	/*
447 	 * It is safe to mask the events here, because acpi_ec_close_event()
448 	 * will run at least once after this.
449 	 */
450 	acpi_ec_mask_events(ec);
451 	if (!acpi_ec_event_enabled(ec))
452 		return;
453 
454 	if (ec->event_state != EC_EVENT_READY)
455 		return;
456 
457 	ec_dbg_evt("Command(%s) submitted/blocked",
458 		   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
459 
460 	ec->event_state = EC_EVENT_IN_PROGRESS;
461 	/*
462 	 * If events_to_process is greater than 0 at this point, the while ()
463 	 * loop in acpi_ec_event_handler() is still running and incrementing
464 	 * events_to_process will cause it to invoke acpi_ec_submit_query() once
465 	 * more, so it is not necessary to queue up the event work to start the
466 	 * same loop again.
467 	 */
468 	if (ec->events_to_process++ > 0)
469 		return;
470 
471 	ec->events_in_progress++;
472 	queue_work(ec_wq, &ec->work);
473 }
474 
acpi_ec_complete_event(struct acpi_ec * ec)475 static void acpi_ec_complete_event(struct acpi_ec *ec)
476 {
477 	if (ec->event_state == EC_EVENT_IN_PROGRESS)
478 		ec->event_state = EC_EVENT_COMPLETE;
479 }
480 
acpi_ec_close_event(struct acpi_ec * ec)481 static void acpi_ec_close_event(struct acpi_ec *ec)
482 {
483 	if (ec->event_state != EC_EVENT_READY)
484 		ec_dbg_evt("Command(%s) unblocked",
485 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
486 
487 	ec->event_state = EC_EVENT_READY;
488 	acpi_ec_unmask_events(ec);
489 }
490 
__acpi_ec_enable_event(struct acpi_ec * ec)491 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
492 {
493 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
494 		ec_log_drv("event unblocked");
495 	/*
496 	 * Unconditionally invoke this once after enabling the event
497 	 * handling mechanism to detect the pending events.
498 	 */
499 	advance_transaction(ec, false);
500 }
501 
__acpi_ec_disable_event(struct acpi_ec * ec)502 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
503 {
504 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
505 		ec_log_drv("event blocked");
506 }
507 
508 /*
509  * Process _Q events that might have accumulated in the EC.
510  * Run with locked ec mutex.
511  */
acpi_ec_clear(struct acpi_ec * ec)512 static void acpi_ec_clear(struct acpi_ec *ec)
513 {
514 	int i;
515 
516 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
517 		if (acpi_ec_submit_query(ec))
518 			break;
519 	}
520 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
521 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
522 	else
523 		pr_info("%d stale EC events cleared\n", i);
524 }
525 
acpi_ec_enable_event(struct acpi_ec * ec)526 static void acpi_ec_enable_event(struct acpi_ec *ec)
527 {
528 	unsigned long flags;
529 
530 	spin_lock_irqsave(&ec->lock, flags);
531 	if (acpi_ec_started(ec))
532 		__acpi_ec_enable_event(ec);
533 	spin_unlock_irqrestore(&ec->lock, flags);
534 
535 	/* Drain additional events if hardware requires that */
536 	if (EC_FLAGS_CLEAR_ON_RESUME)
537 		acpi_ec_clear(ec);
538 }
539 
540 #ifdef CONFIG_PM_SLEEP
__acpi_ec_flush_work(void)541 static void __acpi_ec_flush_work(void)
542 {
543 	flush_workqueue(ec_wq); /* flush ec->work */
544 	flush_workqueue(ec_query_wq); /* flush queries */
545 }
546 
acpi_ec_disable_event(struct acpi_ec * ec)547 static void acpi_ec_disable_event(struct acpi_ec *ec)
548 {
549 	unsigned long flags;
550 
551 	spin_lock_irqsave(&ec->lock, flags);
552 	__acpi_ec_disable_event(ec);
553 	spin_unlock_irqrestore(&ec->lock, flags);
554 
555 	/*
556 	 * When ec_freeze_events is true, we need to flush events in
557 	 * the proper position before entering the noirq stage.
558 	 */
559 	__acpi_ec_flush_work();
560 }
561 
acpi_ec_flush_work(void)562 void acpi_ec_flush_work(void)
563 {
564 	/* Without ec_wq there is nothing to flush. */
565 	if (!ec_wq)
566 		return;
567 
568 	__acpi_ec_flush_work();
569 }
570 #endif /* CONFIG_PM_SLEEP */
571 
acpi_ec_guard_event(struct acpi_ec * ec)572 static bool acpi_ec_guard_event(struct acpi_ec *ec)
573 {
574 	unsigned long flags;
575 	bool guarded;
576 
577 	spin_lock_irqsave(&ec->lock, flags);
578 	/*
579 	 * If firmware SCI_EVT clearing timing is "event", we actually
580 	 * don't know when the SCI_EVT will be cleared by firmware after
581 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
582 	 * acceptable period.
583 	 *
584 	 * The guarding period is applicable if the event state is not
585 	 * EC_EVENT_READY, but otherwise if the current transaction is of the
586 	 * ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
587 	 * and it should not be applied to let the transaction transition into
588 	 * the ACPI_EC_COMMAND_POLL state immediately.
589 	 */
590 	guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
591 		ec->event_state != EC_EVENT_READY &&
592 		(!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
593 	spin_unlock_irqrestore(&ec->lock, flags);
594 	return guarded;
595 }
596 
ec_transaction_polled(struct acpi_ec * ec)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 
ec_transaction_completed(struct acpi_ec * ec)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 
ec_transaction_transition(struct acpi_ec * ec,unsigned long flag)621 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
622 {
623 	ec->curr->flags |= flag;
624 
625 	if (ec->curr->command != ACPI_EC_COMMAND_QUERY)
626 		return;
627 
628 	switch (ec_event_clearing) {
629 	case ACPI_EC_EVT_TIMING_STATUS:
630 		if (flag == ACPI_EC_COMMAND_POLL)
631 			acpi_ec_close_event(ec);
632 
633 		return;
634 
635 	case ACPI_EC_EVT_TIMING_QUERY:
636 		if (flag == ACPI_EC_COMMAND_COMPLETE)
637 			acpi_ec_close_event(ec);
638 
639 		return;
640 
641 	case ACPI_EC_EVT_TIMING_EVENT:
642 		if (flag == ACPI_EC_COMMAND_COMPLETE)
643 			acpi_ec_complete_event(ec);
644 	}
645 }
646 
acpi_ec_spurious_interrupt(struct acpi_ec * ec,struct transaction * t)647 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
648 {
649 	if (t->irq_count < ec_storm_threshold)
650 		++t->irq_count;
651 
652 	/* Trigger if the threshold is 0 too. */
653 	if (t->irq_count == ec_storm_threshold)
654 		acpi_ec_mask_events(ec);
655 }
656 
advance_transaction(struct acpi_ec * ec,bool interrupt)657 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
658 {
659 	struct transaction *t = ec->curr;
660 	bool wakeup = false;
661 	u8 status;
662 
663 	ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
664 
665 	status = acpi_ec_read_status(ec);
666 
667 	/*
668 	 * Another IRQ or a guarded polling mode advancement is detected,
669 	 * the next QR_EC submission is then allowed.
670 	 */
671 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
672 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
673 		    ec->event_state == EC_EVENT_COMPLETE)
674 			acpi_ec_close_event(ec);
675 
676 		if (!t)
677 			goto out;
678 	}
679 
680 	if (t->flags & ACPI_EC_COMMAND_POLL) {
681 		if (t->wlen > t->wi) {
682 			if (!(status & ACPI_EC_FLAG_IBF))
683 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
684 			else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
685 				acpi_ec_spurious_interrupt(ec, t);
686 		} else if (t->rlen > t->ri) {
687 			if (status & ACPI_EC_FLAG_OBF) {
688 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
689 				if (t->rlen == t->ri) {
690 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
691 					wakeup = true;
692 					if (t->command == ACPI_EC_COMMAND_QUERY)
693 						ec_dbg_evt("Command(%s) completed by hardware",
694 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
695 				}
696 			} else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
697 				acpi_ec_spurious_interrupt(ec, t);
698 			}
699 		} else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
700 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
701 			wakeup = true;
702 		}
703 	} else if (!(status & ACPI_EC_FLAG_IBF)) {
704 		acpi_ec_write_cmd(ec, t->command);
705 		ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
706 	}
707 
708 out:
709 	if (status & ACPI_EC_FLAG_SCI)
710 		acpi_ec_submit_event(ec);
711 
712 	if (wakeup && interrupt)
713 		wake_up(&ec->wait);
714 }
715 
start_transaction(struct acpi_ec * ec)716 static void start_transaction(struct acpi_ec *ec)
717 {
718 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
719 	ec->curr->flags = 0;
720 }
721 
ec_guard(struct acpi_ec * ec)722 static int ec_guard(struct acpi_ec *ec)
723 {
724 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
725 	unsigned long timeout = ec->timestamp + guard;
726 
727 	/* Ensure guarding period before polling EC status */
728 	do {
729 		if (ec->busy_polling) {
730 			/* Perform busy polling */
731 			if (ec_transaction_completed(ec))
732 				return 0;
733 			udelay(jiffies_to_usecs(guard));
734 		} else {
735 			/*
736 			 * Perform wait polling
737 			 * 1. Wait the transaction to be completed by the
738 			 *    GPE handler after the transaction enters
739 			 *    ACPI_EC_COMMAND_POLL state.
740 			 * 2. A special guarding logic is also required
741 			 *    for event clearing mode "event" before the
742 			 *    transaction enters ACPI_EC_COMMAND_POLL
743 			 *    state.
744 			 */
745 			if (!ec_transaction_polled(ec) &&
746 			    !acpi_ec_guard_event(ec))
747 				break;
748 			if (wait_event_timeout(ec->wait,
749 					       ec_transaction_completed(ec),
750 					       guard))
751 				return 0;
752 		}
753 	} while (time_before(jiffies, timeout));
754 	return -ETIME;
755 }
756 
ec_poll(struct acpi_ec * ec)757 static int ec_poll(struct acpi_ec *ec)
758 {
759 	unsigned long flags;
760 	int repeat = 5; /* number of command restarts */
761 
762 	while (repeat--) {
763 		unsigned long delay = jiffies +
764 			msecs_to_jiffies(ec_delay);
765 		do {
766 			if (!ec_guard(ec))
767 				return 0;
768 			spin_lock_irqsave(&ec->lock, flags);
769 			advance_transaction(ec, false);
770 			spin_unlock_irqrestore(&ec->lock, flags);
771 		} while (time_before(jiffies, delay));
772 		pr_debug("controller reset, restart transaction\n");
773 		spin_lock_irqsave(&ec->lock, flags);
774 		start_transaction(ec);
775 		spin_unlock_irqrestore(&ec->lock, flags);
776 	}
777 	return -ETIME;
778 }
779 
acpi_ec_transaction_unlocked(struct acpi_ec * ec,struct transaction * t)780 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
781 					struct transaction *t)
782 {
783 	unsigned long tmp;
784 	int ret = 0;
785 
786 	if (t->rdata)
787 		memset(t->rdata, 0, t->rlen);
788 
789 	/* start transaction */
790 	spin_lock_irqsave(&ec->lock, tmp);
791 	/* Enable GPE for command processing (IBF=0/OBF=1) */
792 	if (!acpi_ec_submit_flushable_request(ec)) {
793 		ret = -EINVAL;
794 		goto unlock;
795 	}
796 	ec_dbg_ref(ec, "Increase command");
797 	/* following two actions should be kept atomic */
798 	ec->curr = t;
799 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
800 	start_transaction(ec);
801 	spin_unlock_irqrestore(&ec->lock, tmp);
802 
803 	ret = ec_poll(ec);
804 
805 	spin_lock_irqsave(&ec->lock, tmp);
806 	if (t->irq_count == ec_storm_threshold)
807 		acpi_ec_unmask_events(ec);
808 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
809 	ec->curr = NULL;
810 	/* Disable GPE for command processing (IBF=0/OBF=1) */
811 	acpi_ec_complete_request(ec);
812 	ec_dbg_ref(ec, "Decrease command");
813 unlock:
814 	spin_unlock_irqrestore(&ec->lock, tmp);
815 	return ret;
816 }
817 
acpi_ec_transaction(struct acpi_ec * ec,struct transaction * t)818 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
819 {
820 	int status;
821 	u32 glk;
822 
823 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
824 		return -EINVAL;
825 
826 	mutex_lock(&ec->mutex);
827 	if (ec->global_lock) {
828 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
829 		if (ACPI_FAILURE(status)) {
830 			status = -ENODEV;
831 			goto unlock;
832 		}
833 	}
834 
835 	status = acpi_ec_transaction_unlocked(ec, t);
836 
837 	if (ec->global_lock)
838 		acpi_release_global_lock(glk);
839 unlock:
840 	mutex_unlock(&ec->mutex);
841 	return status;
842 }
843 
acpi_ec_burst_enable(struct acpi_ec * ec)844 static int acpi_ec_burst_enable(struct acpi_ec *ec)
845 {
846 	u8 d;
847 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
848 				.wdata = NULL, .rdata = &d,
849 				.wlen = 0, .rlen = 1};
850 
851 	return acpi_ec_transaction_unlocked(ec, &t);
852 }
853 
acpi_ec_burst_disable(struct acpi_ec * ec)854 static int acpi_ec_burst_disable(struct acpi_ec *ec)
855 {
856 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
857 				.wdata = NULL, .rdata = NULL,
858 				.wlen = 0, .rlen = 0};
859 
860 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
861 				acpi_ec_transaction_unlocked(ec, &t) : 0;
862 }
863 
acpi_ec_read(struct acpi_ec * ec,u8 address,u8 * data)864 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
865 {
866 	int result;
867 	u8 d;
868 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
869 				.wdata = &address, .rdata = &d,
870 				.wlen = 1, .rlen = 1};
871 
872 	result = acpi_ec_transaction(ec, &t);
873 	*data = d;
874 	return result;
875 }
876 
acpi_ec_read_unlocked(struct acpi_ec * ec,u8 address,u8 * data)877 static int acpi_ec_read_unlocked(struct acpi_ec *ec, u8 address, u8 *data)
878 {
879 	int result;
880 	u8 d;
881 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
882 				.wdata = &address, .rdata = &d,
883 				.wlen = 1, .rlen = 1};
884 
885 	result = acpi_ec_transaction_unlocked(ec, &t);
886 	*data = d;
887 	return result;
888 }
889 
acpi_ec_write(struct acpi_ec * ec,u8 address,u8 data)890 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
891 {
892 	u8 wdata[2] = { address, data };
893 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
894 				.wdata = wdata, .rdata = NULL,
895 				.wlen = 2, .rlen = 0};
896 
897 	return acpi_ec_transaction(ec, &t);
898 }
899 
acpi_ec_write_unlocked(struct acpi_ec * ec,u8 address,u8 data)900 static int acpi_ec_write_unlocked(struct acpi_ec *ec, u8 address, u8 data)
901 {
902 	u8 wdata[2] = { address, data };
903 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
904 				.wdata = wdata, .rdata = NULL,
905 				.wlen = 2, .rlen = 0};
906 
907 	return acpi_ec_transaction_unlocked(ec, &t);
908 }
909 
ec_read(u8 addr,u8 * val)910 int ec_read(u8 addr, u8 *val)
911 {
912 	int err;
913 	u8 temp_data;
914 
915 	if (!first_ec)
916 		return -ENODEV;
917 
918 	err = acpi_ec_read(first_ec, addr, &temp_data);
919 
920 	if (!err) {
921 		*val = temp_data;
922 		return 0;
923 	}
924 	return err;
925 }
926 EXPORT_SYMBOL(ec_read);
927 
ec_write(u8 addr,u8 val)928 int ec_write(u8 addr, u8 val)
929 {
930 	if (!first_ec)
931 		return -ENODEV;
932 
933 	return acpi_ec_write(first_ec, addr, val);
934 }
935 EXPORT_SYMBOL(ec_write);
936 
ec_transaction(u8 command,const u8 * wdata,unsigned wdata_len,u8 * rdata,unsigned rdata_len)937 int ec_transaction(u8 command,
938 		   const u8 *wdata, unsigned wdata_len,
939 		   u8 *rdata, unsigned rdata_len)
940 {
941 	struct transaction t = {.command = command,
942 				.wdata = wdata, .rdata = rdata,
943 				.wlen = wdata_len, .rlen = rdata_len};
944 
945 	if (!first_ec)
946 		return -ENODEV;
947 
948 	return acpi_ec_transaction(first_ec, &t);
949 }
950 EXPORT_SYMBOL(ec_transaction);
951 
952 /* Get the handle to the EC device */
ec_get_handle(void)953 acpi_handle ec_get_handle(void)
954 {
955 	if (!first_ec)
956 		return NULL;
957 	return first_ec->handle;
958 }
959 EXPORT_SYMBOL(ec_get_handle);
960 
acpi_ec_start(struct acpi_ec * ec,bool resuming)961 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
962 {
963 	unsigned long flags;
964 
965 	spin_lock_irqsave(&ec->lock, flags);
966 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
967 		ec_dbg_drv("Starting EC");
968 		/* Enable GPE for event processing (SCI_EVT=1) */
969 		if (!resuming) {
970 			acpi_ec_submit_request(ec);
971 			ec_dbg_ref(ec, "Increase driver");
972 		}
973 		ec_log_drv("EC started");
974 	}
975 	spin_unlock_irqrestore(&ec->lock, flags);
976 }
977 
acpi_ec_stopped(struct acpi_ec * ec)978 static bool acpi_ec_stopped(struct acpi_ec *ec)
979 {
980 	unsigned long flags;
981 	bool flushed;
982 
983 	spin_lock_irqsave(&ec->lock, flags);
984 	flushed = acpi_ec_flushed(ec);
985 	spin_unlock_irqrestore(&ec->lock, flags);
986 	return flushed;
987 }
988 
acpi_ec_stop(struct acpi_ec * ec,bool suspending)989 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
990 {
991 	unsigned long flags;
992 
993 	spin_lock_irqsave(&ec->lock, flags);
994 	if (acpi_ec_started(ec)) {
995 		ec_dbg_drv("Stopping EC");
996 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
997 		spin_unlock_irqrestore(&ec->lock, flags);
998 		wait_event(ec->wait, acpi_ec_stopped(ec));
999 		spin_lock_irqsave(&ec->lock, flags);
1000 		/* Disable GPE for event processing (SCI_EVT=1) */
1001 		if (!suspending) {
1002 			acpi_ec_complete_request(ec);
1003 			ec_dbg_ref(ec, "Decrease driver");
1004 		} else if (!ec_freeze_events)
1005 			__acpi_ec_disable_event(ec);
1006 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
1007 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1008 		ec_log_drv("EC stopped");
1009 	}
1010 	spin_unlock_irqrestore(&ec->lock, flags);
1011 }
1012 
acpi_ec_enter_noirq(struct acpi_ec * ec)1013 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1014 {
1015 	unsigned long flags;
1016 
1017 	spin_lock_irqsave(&ec->lock, flags);
1018 	ec->busy_polling = true;
1019 	ec->polling_guard = 0;
1020 	ec_log_drv("interrupt blocked");
1021 	spin_unlock_irqrestore(&ec->lock, flags);
1022 }
1023 
acpi_ec_leave_noirq(struct acpi_ec * ec)1024 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1025 {
1026 	unsigned long flags;
1027 
1028 	spin_lock_irqsave(&ec->lock, flags);
1029 	ec->busy_polling = ec_busy_polling;
1030 	ec->polling_guard = ec_polling_guard;
1031 	ec_log_drv("interrupt unblocked");
1032 	spin_unlock_irqrestore(&ec->lock, flags);
1033 }
1034 
acpi_ec_block_transactions(void)1035 void acpi_ec_block_transactions(void)
1036 {
1037 	struct acpi_ec *ec = first_ec;
1038 
1039 	if (!ec)
1040 		return;
1041 
1042 	mutex_lock(&ec->mutex);
1043 	/* Prevent transactions from being carried out */
1044 	acpi_ec_stop(ec, true);
1045 	mutex_unlock(&ec->mutex);
1046 }
1047 
acpi_ec_unblock_transactions(void)1048 void acpi_ec_unblock_transactions(void)
1049 {
1050 	/*
1051 	 * Allow transactions to happen again (this function is called from
1052 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1053 	 */
1054 	if (first_ec)
1055 		acpi_ec_start(first_ec, true);
1056 }
1057 
1058 /* --------------------------------------------------------------------------
1059                                 Event Management
1060    -------------------------------------------------------------------------- */
1061 static struct acpi_ec_query_handler *
acpi_ec_get_query_handler_by_value(struct acpi_ec * ec,u8 value)1062 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1063 {
1064 	struct acpi_ec_query_handler *handler;
1065 
1066 	mutex_lock(&ec->mutex);
1067 	list_for_each_entry(handler, &ec->list, node) {
1068 		if (value == handler->query_bit) {
1069 			kref_get(&handler->kref);
1070 			mutex_unlock(&ec->mutex);
1071 			return handler;
1072 		}
1073 	}
1074 	mutex_unlock(&ec->mutex);
1075 	return NULL;
1076 }
1077 
acpi_ec_query_handler_release(struct kref * kref)1078 static void acpi_ec_query_handler_release(struct kref *kref)
1079 {
1080 	struct acpi_ec_query_handler *handler =
1081 		container_of(kref, struct acpi_ec_query_handler, kref);
1082 
1083 	kfree(handler);
1084 }
1085 
acpi_ec_put_query_handler(struct acpi_ec_query_handler * handler)1086 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1087 {
1088 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1089 }
1090 
acpi_ec_add_query_handler(struct acpi_ec * ec,u8 query_bit,acpi_handle handle,acpi_ec_query_func func,void * data)1091 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1092 			      acpi_handle handle, acpi_ec_query_func func,
1093 			      void *data)
1094 {
1095 	struct acpi_ec_query_handler *handler;
1096 
1097 	if (!handle && !func)
1098 		return -EINVAL;
1099 
1100 	handler = kzalloc(sizeof(*handler), GFP_KERNEL);
1101 	if (!handler)
1102 		return -ENOMEM;
1103 
1104 	handler->query_bit = query_bit;
1105 	handler->handle = handle;
1106 	handler->func = func;
1107 	handler->data = data;
1108 	mutex_lock(&ec->mutex);
1109 	kref_init(&handler->kref);
1110 	list_add(&handler->node, &ec->list);
1111 	mutex_unlock(&ec->mutex);
1112 
1113 	return 0;
1114 }
1115 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1116 
acpi_ec_remove_query_handlers(struct acpi_ec * ec,bool remove_all,u8 query_bit)1117 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1118 					  bool remove_all, u8 query_bit)
1119 {
1120 	struct acpi_ec_query_handler *handler, *tmp;
1121 	LIST_HEAD(free_list);
1122 
1123 	mutex_lock(&ec->mutex);
1124 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1125 		/*
1126 		 * When remove_all is false, only remove custom query handlers
1127 		 * which have handler->func set. This is done to preserve query
1128 		 * handlers discovered thru ACPI, as they should continue handling
1129 		 * EC queries.
1130 		 */
1131 		if (remove_all || (handler->func && handler->query_bit == query_bit)) {
1132 			list_del_init(&handler->node);
1133 			list_add(&handler->node, &free_list);
1134 
1135 		}
1136 	}
1137 	mutex_unlock(&ec->mutex);
1138 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1139 		acpi_ec_put_query_handler(handler);
1140 }
1141 
acpi_ec_remove_query_handler(struct acpi_ec * ec,u8 query_bit)1142 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1143 {
1144 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1145 	flush_workqueue(ec_query_wq);
1146 }
1147 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1148 
acpi_ec_event_processor(struct work_struct * work)1149 static void acpi_ec_event_processor(struct work_struct *work)
1150 {
1151 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1152 	struct acpi_ec_query_handler *handler = q->handler;
1153 	struct acpi_ec *ec = q->ec;
1154 
1155 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1156 
1157 	if (handler->func)
1158 		handler->func(handler->data);
1159 	else if (handler->handle)
1160 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1161 
1162 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1163 
1164 	spin_lock_irq(&ec->lock);
1165 	ec->queries_in_progress--;
1166 	spin_unlock_irq(&ec->lock);
1167 
1168 	acpi_ec_put_query_handler(handler);
1169 	kfree(q);
1170 }
1171 
acpi_ec_create_query(struct acpi_ec * ec,u8 * pval)1172 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1173 {
1174 	struct acpi_ec_query *q;
1175 	struct transaction *t;
1176 
1177 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1178 	if (!q)
1179 		return NULL;
1180 
1181 	INIT_WORK(&q->work, acpi_ec_event_processor);
1182 	t = &q->transaction;
1183 	t->command = ACPI_EC_COMMAND_QUERY;
1184 	t->rdata = pval;
1185 	t->rlen = 1;
1186 	q->ec = ec;
1187 	return q;
1188 }
1189 
acpi_ec_submit_query(struct acpi_ec * ec)1190 static int acpi_ec_submit_query(struct acpi_ec *ec)
1191 {
1192 	struct acpi_ec_query *q;
1193 	u8 value = 0;
1194 	int result;
1195 
1196 	q = acpi_ec_create_query(ec, &value);
1197 	if (!q)
1198 		return -ENOMEM;
1199 
1200 	/*
1201 	 * Query the EC to find out which _Qxx method we need to evaluate.
1202 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1203 	 * bit to be cleared (and thus clearing the interrupt source).
1204 	 */
1205 	result = acpi_ec_transaction(ec, &q->transaction);
1206 	if (result)
1207 		goto err_exit;
1208 
1209 	if (!value) {
1210 		result = -ENODATA;
1211 		goto err_exit;
1212 	}
1213 
1214 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1215 	if (!q->handler) {
1216 		result = -ENODATA;
1217 		goto err_exit;
1218 	}
1219 
1220 	/*
1221 	 * It is reported that _Qxx are evaluated in a parallel way on Windows:
1222 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1223 	 *
1224 	 * Put this log entry before queue_work() to make it appear in the log
1225 	 * before any other messages emitted during workqueue handling.
1226 	 */
1227 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1228 
1229 	spin_lock_irq(&ec->lock);
1230 
1231 	ec->queries_in_progress++;
1232 	queue_work(ec_query_wq, &q->work);
1233 
1234 	spin_unlock_irq(&ec->lock);
1235 
1236 	return 0;
1237 
1238 err_exit:
1239 	kfree(q);
1240 
1241 	return result;
1242 }
1243 
acpi_ec_event_handler(struct work_struct * work)1244 static void acpi_ec_event_handler(struct work_struct *work)
1245 {
1246 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1247 
1248 	ec_dbg_evt("Event started");
1249 
1250 	spin_lock_irq(&ec->lock);
1251 
1252 	while (ec->events_to_process) {
1253 		spin_unlock_irq(&ec->lock);
1254 
1255 		acpi_ec_submit_query(ec);
1256 
1257 		spin_lock_irq(&ec->lock);
1258 
1259 		ec->events_to_process--;
1260 	}
1261 
1262 	/*
1263 	 * Before exit, make sure that the it will be possible to queue up the
1264 	 * event handling work again regardless of whether or not the query
1265 	 * queued up above is processed successfully.
1266 	 */
1267 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1268 		bool guard_timeout;
1269 
1270 		acpi_ec_complete_event(ec);
1271 
1272 		ec_dbg_evt("Event stopped");
1273 
1274 		spin_unlock_irq(&ec->lock);
1275 
1276 		guard_timeout = !!ec_guard(ec);
1277 
1278 		spin_lock_irq(&ec->lock);
1279 
1280 		/* Take care of SCI_EVT unless someone else is doing that. */
1281 		if (guard_timeout && !ec->curr)
1282 			advance_transaction(ec, false);
1283 	} else {
1284 		acpi_ec_close_event(ec);
1285 
1286 		ec_dbg_evt("Event stopped");
1287 	}
1288 
1289 	ec->events_in_progress--;
1290 
1291 	spin_unlock_irq(&ec->lock);
1292 }
1293 
clear_gpe_and_advance_transaction(struct acpi_ec * ec,bool interrupt)1294 static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)
1295 {
1296 	/*
1297 	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
1298 	 * changes to always trigger a GPE interrupt.
1299 	 *
1300 	 * GPE STS is a W1C register, which means:
1301 	 *
1302 	 * 1. Software can clear it without worrying about clearing the other
1303 	 *    GPEs' STS bits when the hardware sets them in parallel.
1304 	 *
1305 	 * 2. As long as software can ensure only clearing it when it is set,
1306 	 *    hardware won't set it in parallel.
1307 	 */
1308 	if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
1309 		acpi_clear_gpe(NULL, ec->gpe);
1310 
1311 	advance_transaction(ec, true);
1312 }
1313 
acpi_ec_handle_interrupt(struct acpi_ec * ec)1314 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1315 {
1316 	unsigned long flags;
1317 
1318 	spin_lock_irqsave(&ec->lock, flags);
1319 
1320 	clear_gpe_and_advance_transaction(ec, true);
1321 
1322 	spin_unlock_irqrestore(&ec->lock, flags);
1323 }
1324 
acpi_ec_gpe_handler(acpi_handle gpe_device,u32 gpe_number,void * data)1325 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1326 			       u32 gpe_number, void *data)
1327 {
1328 	acpi_ec_handle_interrupt(data);
1329 	return ACPI_INTERRUPT_HANDLED;
1330 }
1331 
acpi_ec_irq_handler(int irq,void * data)1332 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1333 {
1334 	acpi_ec_handle_interrupt(data);
1335 	return IRQ_HANDLED;
1336 }
1337 
1338 /* --------------------------------------------------------------------------
1339  *                           Address Space Management
1340  * -------------------------------------------------------------------------- */
1341 
1342 static acpi_status
acpi_ec_space_handler(u32 function,acpi_physical_address address,u32 bits,u64 * value64,void * handler_context,void * region_context)1343 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1344 		      u32 bits, u64 *value64,
1345 		      void *handler_context, void *region_context)
1346 {
1347 	struct acpi_ec *ec = handler_context;
1348 	int result = 0, i, bytes = bits / 8;
1349 	u8 *value = (u8 *)value64;
1350 	u32 glk;
1351 
1352 	if ((address > 0xFF) || !value || !handler_context)
1353 		return AE_BAD_PARAMETER;
1354 
1355 	if (function != ACPI_READ && function != ACPI_WRITE)
1356 		return AE_BAD_PARAMETER;
1357 
1358 	mutex_lock(&ec->mutex);
1359 
1360 	if (ec->global_lock) {
1361 		acpi_status status;
1362 
1363 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
1364 		if (ACPI_FAILURE(status)) {
1365 			result = -ENODEV;
1366 			goto unlock;
1367 		}
1368 	}
1369 
1370 	if (ec->busy_polling || bits > 8)
1371 		acpi_ec_burst_enable(ec);
1372 
1373 	for (i = 0; i < bytes; ++i, ++address, ++value) {
1374 		result = (function == ACPI_READ) ?
1375 			acpi_ec_read_unlocked(ec, address, value) :
1376 			acpi_ec_write_unlocked(ec, address, *value);
1377 		if (result < 0)
1378 			break;
1379 	}
1380 
1381 	if (ec->busy_polling || bits > 8)
1382 		acpi_ec_burst_disable(ec);
1383 
1384 	if (ec->global_lock)
1385 		acpi_release_global_lock(glk);
1386 
1387 unlock:
1388 	mutex_unlock(&ec->mutex);
1389 
1390 	switch (result) {
1391 	case -EINVAL:
1392 		return AE_BAD_PARAMETER;
1393 	case -ENODEV:
1394 		return AE_NOT_FOUND;
1395 	case -ETIME:
1396 		return AE_TIME;
1397 	case 0:
1398 		return AE_OK;
1399 	default:
1400 		return AE_ERROR;
1401 	}
1402 }
1403 
1404 /* --------------------------------------------------------------------------
1405  *                             Driver Interface
1406  * -------------------------------------------------------------------------- */
1407 
1408 static acpi_status
1409 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1410 
acpi_ec_free(struct acpi_ec * ec)1411 static void acpi_ec_free(struct acpi_ec *ec)
1412 {
1413 	if (first_ec == ec)
1414 		first_ec = NULL;
1415 	if (boot_ec == ec)
1416 		boot_ec = NULL;
1417 	kfree(ec);
1418 }
1419 
acpi_ec_alloc(void)1420 static struct acpi_ec *acpi_ec_alloc(void)
1421 {
1422 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1423 
1424 	if (!ec)
1425 		return NULL;
1426 	mutex_init(&ec->mutex);
1427 	init_waitqueue_head(&ec->wait);
1428 	INIT_LIST_HEAD(&ec->list);
1429 	spin_lock_init(&ec->lock);
1430 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1431 	ec->timestamp = jiffies;
1432 	ec->busy_polling = true;
1433 	ec->polling_guard = 0;
1434 	ec->gpe = -1;
1435 	ec->irq = -1;
1436 	return ec;
1437 }
1438 
1439 static acpi_status
acpi_ec_register_query_methods(acpi_handle handle,u32 level,void * context,void ** return_value)1440 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1441 			       void *context, void **return_value)
1442 {
1443 	char node_name[5];
1444 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1445 	struct acpi_ec *ec = context;
1446 	int value = 0;
1447 	acpi_status status;
1448 
1449 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1450 
1451 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1452 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1453 	return AE_OK;
1454 }
1455 
1456 static acpi_status
ec_parse_device(acpi_handle handle,u32 Level,void * context,void ** retval)1457 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1458 {
1459 	acpi_status status;
1460 	unsigned long long tmp = 0;
1461 	struct acpi_ec *ec = context;
1462 
1463 	/* clear addr values, ec_parse_io_ports depend on it */
1464 	ec->command_addr = ec->data_addr = 0;
1465 
1466 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1467 				     ec_parse_io_ports, ec);
1468 	if (ACPI_FAILURE(status))
1469 		return status;
1470 	if (ec->data_addr == 0 || ec->command_addr == 0)
1471 		return AE_OK;
1472 
1473 	/* Get GPE bit assignment (EC events). */
1474 	/* TODO: Add support for _GPE returning a package */
1475 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1476 	if (ACPI_SUCCESS(status))
1477 		ec->gpe = tmp;
1478 	/*
1479 	 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1480 	 * platforms which use GpioInt instead of GPE.
1481 	 */
1482 
1483 	/* Use the global lock for all EC transactions? */
1484 	tmp = 0;
1485 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1486 	ec->global_lock = tmp;
1487 	ec->handle = handle;
1488 	return AE_CTRL_TERMINATE;
1489 }
1490 
install_gpe_event_handler(struct acpi_ec * ec)1491 static bool install_gpe_event_handler(struct acpi_ec *ec)
1492 {
1493 	acpi_status status;
1494 
1495 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1496 					      ACPI_GPE_EDGE_TRIGGERED,
1497 					      &acpi_ec_gpe_handler, ec);
1498 	if (ACPI_FAILURE(status))
1499 		return false;
1500 
1501 	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1502 		acpi_ec_enable_gpe(ec, true);
1503 
1504 	return true;
1505 }
1506 
install_gpio_irq_event_handler(struct acpi_ec * ec)1507 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1508 {
1509 	return request_threaded_irq(ec->irq, NULL, acpi_ec_irq_handler,
1510 				    IRQF_SHARED | IRQF_ONESHOT, "ACPI EC", ec) >= 0;
1511 }
1512 
1513 /**
1514  * ec_install_handlers - Install service callbacks and register query methods.
1515  * @ec: Target EC.
1516  * @device: ACPI device object corresponding to @ec.
1517  * @call_reg: If _REG should be called to notify OpRegion availability
1518  *
1519  * Install a handler for the EC address space type unless it has been installed
1520  * already.  If @device is not NULL, also look for EC query methods in the
1521  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1522  * handler for the EC, if possible.
1523  *
1524  * Return:
1525  * -ENODEV if the address space handler cannot be installed, which means
1526  *  "unable to handle transactions",
1527  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1528  * or 0 (success) otherwise.
1529  */
ec_install_handlers(struct acpi_ec * ec,struct acpi_device * device,bool call_reg)1530 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1531 			       bool call_reg)
1532 {
1533 	acpi_status status;
1534 
1535 	acpi_ec_start(ec, false);
1536 
1537 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1538 		acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1539 
1540 		acpi_ec_enter_noirq(ec);
1541 		status = acpi_install_address_space_handler_no_reg(scope_handle,
1542 								   ACPI_ADR_SPACE_EC,
1543 								   &acpi_ec_space_handler,
1544 								   NULL, ec);
1545 		if (ACPI_FAILURE(status)) {
1546 			acpi_ec_stop(ec, false);
1547 			return -ENODEV;
1548 		}
1549 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1550 	}
1551 
1552 	if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
1553 		acpi_execute_reg_methods(ec->handle, ACPI_UINT32_MAX, ACPI_ADR_SPACE_EC);
1554 		set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
1555 	}
1556 
1557 	if (!device)
1558 		return 0;
1559 
1560 	if (ec->gpe < 0) {
1561 		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1562 		int irq = acpi_dev_gpio_irq_get(device, 0);
1563 		/*
1564 		 * Bail out right away for deferred probing or complete the
1565 		 * initialization regardless of any other errors.
1566 		 */
1567 		if (irq == -EPROBE_DEFER)
1568 			return -EPROBE_DEFER;
1569 		else if (irq >= 0)
1570 			ec->irq = irq;
1571 	}
1572 
1573 	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1574 		/* Find and register all query methods */
1575 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1576 				    acpi_ec_register_query_methods,
1577 				    NULL, ec, NULL);
1578 		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1579 	}
1580 	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1581 		bool ready = false;
1582 
1583 		if (ec->gpe >= 0)
1584 			ready = install_gpe_event_handler(ec);
1585 		else if (ec->irq >= 0)
1586 			ready = install_gpio_irq_event_handler(ec);
1587 
1588 		if (ready) {
1589 			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1590 			acpi_ec_leave_noirq(ec);
1591 		}
1592 		/*
1593 		 * Failures to install an event handler are not fatal, because
1594 		 * the EC can be polled for events.
1595 		 */
1596 	}
1597 	/* EC is fully operational, allow queries */
1598 	acpi_ec_enable_event(ec);
1599 
1600 	return 0;
1601 }
1602 
ec_remove_handlers(struct acpi_ec * ec)1603 static void ec_remove_handlers(struct acpi_ec *ec)
1604 {
1605 	acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1606 
1607 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1608 		if (ACPI_FAILURE(acpi_remove_address_space_handler(
1609 						scope_handle,
1610 						ACPI_ADR_SPACE_EC,
1611 						&acpi_ec_space_handler)))
1612 			pr_err("failed to remove space handler\n");
1613 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1614 	}
1615 
1616 	/*
1617 	 * Stops handling the EC transactions after removing the operation
1618 	 * region handler. This is required because _REG(DISCONNECT)
1619 	 * invoked during the removal can result in new EC transactions.
1620 	 *
1621 	 * Flushes the EC requests and thus disables the GPE before
1622 	 * removing the GPE handler. This is required by the current ACPICA
1623 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1624 	 * it is indicated but there is no way to handle it. So the drivers
1625 	 * must disable the GPEs prior to removing the GPE handlers.
1626 	 */
1627 	acpi_ec_stop(ec, false);
1628 
1629 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1630 		if (ec->gpe >= 0 &&
1631 		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1632 				 &acpi_ec_gpe_handler)))
1633 			pr_err("failed to remove gpe handler\n");
1634 
1635 		if (ec->irq >= 0)
1636 			free_irq(ec->irq, ec);
1637 
1638 		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1639 	}
1640 	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1641 		acpi_ec_remove_query_handlers(ec, true, 0);
1642 		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1643 	}
1644 }
1645 
acpi_ec_setup(struct acpi_ec * ec,struct acpi_device * device,bool call_reg)1646 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
1647 {
1648 	int ret;
1649 
1650 	/* First EC capable of handling transactions */
1651 	if (!first_ec)
1652 		first_ec = ec;
1653 
1654 	ret = ec_install_handlers(ec, device, call_reg);
1655 	if (ret) {
1656 		if (ec == first_ec)
1657 			first_ec = NULL;
1658 
1659 		return ret;
1660 	}
1661 
1662 	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1663 		ec->data_addr);
1664 
1665 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1666 		if (ec->gpe >= 0)
1667 			pr_info("GPE=0x%x\n", ec->gpe);
1668 		else
1669 			pr_info("IRQ=%d\n", ec->irq);
1670 	}
1671 
1672 	return ret;
1673 }
1674 
acpi_ec_add(struct acpi_device * device)1675 static int acpi_ec_add(struct acpi_device *device)
1676 {
1677 	struct acpi_ec *ec;
1678 	int ret;
1679 
1680 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1681 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1682 
1683 	if (boot_ec && (boot_ec->handle == device->handle ||
1684 	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1685 		/* Fast path: this device corresponds to the boot EC. */
1686 		ec = boot_ec;
1687 	} else {
1688 		acpi_status status;
1689 
1690 		ec = acpi_ec_alloc();
1691 		if (!ec)
1692 			return -ENOMEM;
1693 
1694 		status = ec_parse_device(device->handle, 0, ec, NULL);
1695 		if (status != AE_CTRL_TERMINATE) {
1696 			ret = -EINVAL;
1697 			goto err;
1698 		}
1699 
1700 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1701 		    ec->data_addr == boot_ec->data_addr) {
1702 			/*
1703 			 * Trust PNP0C09 namespace location rather than ECDT ID.
1704 			 * But trust ECDT GPE rather than _GPE because of ASUS
1705 			 * quirks. So do not change boot_ec->gpe to ec->gpe,
1706 			 * except when the TRUST_DSDT_GPE quirk is set.
1707 			 */
1708 			boot_ec->handle = ec->handle;
1709 
1710 			if (EC_FLAGS_TRUST_DSDT_GPE)
1711 				boot_ec->gpe = ec->gpe;
1712 
1713 			acpi_handle_debug(ec->handle, "duplicated.\n");
1714 			acpi_ec_free(ec);
1715 			ec = boot_ec;
1716 		}
1717 	}
1718 
1719 	ret = acpi_ec_setup(ec, device, true);
1720 	if (ret)
1721 		goto err;
1722 
1723 	if (ec == boot_ec)
1724 		acpi_handle_info(boot_ec->handle,
1725 				 "Boot %s EC initialization complete\n",
1726 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1727 
1728 	acpi_handle_info(ec->handle,
1729 			 "EC: Used to handle transactions and events\n");
1730 
1731 	device->driver_data = ec;
1732 
1733 	ret = !!request_region(ec->data_addr, 1, "EC data");
1734 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1735 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1736 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1737 
1738 	/* Reprobe devices depending on the EC */
1739 	acpi_dev_clear_dependencies(device);
1740 
1741 	acpi_handle_debug(ec->handle, "enumerated.\n");
1742 	return 0;
1743 
1744 err:
1745 	if (ec != boot_ec)
1746 		acpi_ec_free(ec);
1747 
1748 	return ret;
1749 }
1750 
acpi_ec_remove(struct acpi_device * device)1751 static void acpi_ec_remove(struct acpi_device *device)
1752 {
1753 	struct acpi_ec *ec;
1754 
1755 	if (!device)
1756 		return;
1757 
1758 	ec = acpi_driver_data(device);
1759 	release_region(ec->data_addr, 1);
1760 	release_region(ec->command_addr, 1);
1761 	device->driver_data = NULL;
1762 	if (ec != boot_ec) {
1763 		ec_remove_handlers(ec);
1764 		acpi_ec_free(ec);
1765 	}
1766 }
1767 
acpi_ec_register_opregions(struct acpi_device * adev)1768 void acpi_ec_register_opregions(struct acpi_device *adev)
1769 {
1770 	if (first_ec && first_ec->handle != adev->handle)
1771 		acpi_execute_reg_methods(adev->handle, 1, ACPI_ADR_SPACE_EC);
1772 }
1773 
1774 static acpi_status
ec_parse_io_ports(struct acpi_resource * resource,void * context)1775 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1776 {
1777 	struct acpi_ec *ec = context;
1778 
1779 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1780 		return AE_OK;
1781 
1782 	/*
1783 	 * The first address region returned is the data port, and
1784 	 * the second address region returned is the status/command
1785 	 * port.
1786 	 */
1787 	if (ec->data_addr == 0)
1788 		ec->data_addr = resource->data.io.minimum;
1789 	else if (ec->command_addr == 0)
1790 		ec->command_addr = resource->data.io.minimum;
1791 	else
1792 		return AE_CTRL_TERMINATE;
1793 
1794 	return AE_OK;
1795 }
1796 
1797 static const struct acpi_device_id ec_device_ids[] = {
1798 	{"PNP0C09", 0},
1799 	{ACPI_ECDT_HID, 0},
1800 	{"", 0},
1801 };
1802 
1803 /*
1804  * This function is not Windows-compatible as Windows never enumerates the
1805  * namespace EC before the main ACPI device enumeration process. It is
1806  * retained for historical reason and will be deprecated in the future.
1807  */
acpi_ec_dsdt_probe(void)1808 void __init acpi_ec_dsdt_probe(void)
1809 {
1810 	struct acpi_ec *ec;
1811 	acpi_status status;
1812 	int ret;
1813 
1814 	/*
1815 	 * If a platform has ECDT, there is no need to proceed as the
1816 	 * following probe is not a part of the ACPI device enumeration,
1817 	 * executing _STA is not safe, and thus this probe may risk of
1818 	 * picking up an invalid EC device.
1819 	 */
1820 	if (boot_ec)
1821 		return;
1822 
1823 	ec = acpi_ec_alloc();
1824 	if (!ec)
1825 		return;
1826 
1827 	/*
1828 	 * At this point, the namespace is initialized, so start to find
1829 	 * the namespace objects.
1830 	 */
1831 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1832 	if (ACPI_FAILURE(status) || !ec->handle) {
1833 		acpi_ec_free(ec);
1834 		return;
1835 	}
1836 
1837 	/*
1838 	 * When the DSDT EC is available, always re-configure boot EC to
1839 	 * have _REG evaluated. _REG can only be evaluated after the
1840 	 * namespace initialization.
1841 	 * At this point, the GPE is not fully initialized, so do not to
1842 	 * handle the events.
1843 	 */
1844 	ret = acpi_ec_setup(ec, NULL, true);
1845 	if (ret) {
1846 		acpi_ec_free(ec);
1847 		return;
1848 	}
1849 
1850 	boot_ec = ec;
1851 
1852 	acpi_handle_info(ec->handle,
1853 			 "Boot DSDT EC used to handle transactions\n");
1854 }
1855 
1856 /*
1857  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1858  *
1859  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1860  * found a matching object in the namespace.
1861  *
1862  * Next, in case the DSDT EC is not functioning, it is still necessary to
1863  * provide a functional ECDT EC to handle events, so add an extra device object
1864  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1865  *
1866  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1867  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1868  */
acpi_ec_ecdt_start(void)1869 static void __init acpi_ec_ecdt_start(void)
1870 {
1871 	struct acpi_table_ecdt *ecdt_ptr;
1872 	acpi_handle handle;
1873 	acpi_status status;
1874 
1875 	/* Bail out if a matching EC has been found in the namespace. */
1876 	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1877 		return;
1878 
1879 	/* Look up the object pointed to from the ECDT in the namespace. */
1880 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1881 				(struct acpi_table_header **)&ecdt_ptr);
1882 	if (ACPI_FAILURE(status))
1883 		return;
1884 
1885 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1886 	if (ACPI_SUCCESS(status)) {
1887 		boot_ec->handle = handle;
1888 
1889 		/* Add a special ACPI device object to represent the boot EC. */
1890 		acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1891 	}
1892 
1893 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1894 }
1895 
1896 /*
1897  * On some hardware it is necessary to clear events accumulated by the EC during
1898  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1899  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1900  *
1901  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1902  *
1903  * Ideally, the EC should also be instructed NOT to accumulate events during
1904  * sleep (which Windows seems to do somehow), but the interface to control this
1905  * behaviour is not known at this time.
1906  *
1907  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1908  * however it is very likely that other Samsung models are affected.
1909  *
1910  * On systems which don't accumulate _Q events during sleep, this extra check
1911  * should be harmless.
1912  */
ec_clear_on_resume(const struct dmi_system_id * id)1913 static int ec_clear_on_resume(const struct dmi_system_id *id)
1914 {
1915 	pr_debug("Detected system needing EC poll on resume.\n");
1916 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1917 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1918 	return 0;
1919 }
1920 
1921 /*
1922  * Some ECDTs contain wrong register addresses.
1923  * MSI MS-171F
1924  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1925  */
ec_correct_ecdt(const struct dmi_system_id * id)1926 static int ec_correct_ecdt(const struct dmi_system_id *id)
1927 {
1928 	pr_debug("Detected system needing ECDT address correction.\n");
1929 	EC_FLAGS_CORRECT_ECDT = 1;
1930 	return 0;
1931 }
1932 
1933 /*
1934  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1935  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1936  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1937  */
ec_honor_dsdt_gpe(const struct dmi_system_id * id)1938 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1939 {
1940 	pr_debug("Detected system needing DSDT GPE setting.\n");
1941 	EC_FLAGS_TRUST_DSDT_GPE = 1;
1942 	return 0;
1943 }
1944 
1945 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1946 	{
1947 		/*
1948 		 * MSI MS-171F
1949 		 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1950 		 */
1951 		.callback = ec_correct_ecdt,
1952 		.matches = {
1953 			DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1954 			DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1955 		},
1956 	},
1957 	{
1958 		/*
1959 		 * HP Pavilion Gaming Laptop 15-cx0xxx
1960 		 * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1961 		 */
1962 		.callback = ec_honor_dsdt_gpe,
1963 		.matches = {
1964 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1965 			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1966 		},
1967 	},
1968 	{
1969 		/*
1970 		 * HP Pavilion Gaming Laptop 15-cx0041ur
1971 		 */
1972 		.callback = ec_honor_dsdt_gpe,
1973 		.matches = {
1974 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1975 			DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
1976 		},
1977 	},
1978 	{
1979 		/*
1980 		 * HP Pavilion Gaming Laptop 15-dk1xxx
1981 		 * https://github.com/systemd/systemd/issues/28942
1982 		 */
1983 		.callback = ec_honor_dsdt_gpe,
1984 		.matches = {
1985 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1986 			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-dk1xxx"),
1987 		},
1988 	},
1989 	{
1990 		/*
1991 		 * HP 250 G7 Notebook PC
1992 		 */
1993 		.callback = ec_honor_dsdt_gpe,
1994 		.matches = {
1995 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1996 			DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G7 Notebook PC"),
1997 		},
1998 	},
1999 	{
2000 		/*
2001 		 * Samsung hardware
2002 		 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
2003 		 */
2004 		.callback = ec_clear_on_resume,
2005 		.matches = {
2006 			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
2007 		},
2008 	},
2009 	{}
2010 };
2011 
acpi_ec_ecdt_probe(void)2012 void __init acpi_ec_ecdt_probe(void)
2013 {
2014 	struct acpi_table_ecdt *ecdt_ptr;
2015 	struct acpi_ec *ec;
2016 	acpi_status status;
2017 	int ret;
2018 
2019 	/* Generate a boot ec context. */
2020 	dmi_check_system(ec_dmi_table);
2021 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
2022 				(struct acpi_table_header **)&ecdt_ptr);
2023 	if (ACPI_FAILURE(status))
2024 		return;
2025 
2026 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
2027 		/*
2028 		 * Asus X50GL:
2029 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
2030 		 */
2031 		goto out;
2032 	}
2033 
2034 	ec = acpi_ec_alloc();
2035 	if (!ec)
2036 		goto out;
2037 
2038 	if (EC_FLAGS_CORRECT_ECDT) {
2039 		ec->command_addr = ecdt_ptr->data.address;
2040 		ec->data_addr = ecdt_ptr->control.address;
2041 	} else {
2042 		ec->command_addr = ecdt_ptr->control.address;
2043 		ec->data_addr = ecdt_ptr->data.address;
2044 	}
2045 
2046 	/*
2047 	 * Ignore the GPE value on Reduced Hardware platforms.
2048 	 * Some products have this set to an erroneous value.
2049 	 */
2050 	if (!acpi_gbl_reduced_hardware)
2051 		ec->gpe = ecdt_ptr->gpe;
2052 
2053 	ec->handle = ACPI_ROOT_OBJECT;
2054 
2055 	/*
2056 	 * At this point, the namespace is not initialized, so do not find
2057 	 * the namespace objects, or handle the events.
2058 	 */
2059 	ret = acpi_ec_setup(ec, NULL, false);
2060 	if (ret) {
2061 		acpi_ec_free(ec);
2062 		goto out;
2063 	}
2064 
2065 	boot_ec = ec;
2066 	boot_ec_is_ecdt = true;
2067 
2068 	pr_info("Boot ECDT EC used to handle transactions\n");
2069 
2070 out:
2071 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
2072 }
2073 
2074 #ifdef CONFIG_PM_SLEEP
acpi_ec_suspend(struct device * dev)2075 static int acpi_ec_suspend(struct device *dev)
2076 {
2077 	struct acpi_ec *ec =
2078 		acpi_driver_data(to_acpi_device(dev));
2079 
2080 	if (!pm_suspend_no_platform() && ec_freeze_events)
2081 		acpi_ec_disable_event(ec);
2082 	return 0;
2083 }
2084 
acpi_ec_suspend_noirq(struct device * dev)2085 static int acpi_ec_suspend_noirq(struct device *dev)
2086 {
2087 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2088 
2089 	/*
2090 	 * The SCI handler doesn't run at this point, so the GPE can be
2091 	 * masked at the low level without side effects.
2092 	 */
2093 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2094 	    ec->gpe >= 0 && ec->reference_count >= 1)
2095 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
2096 
2097 	acpi_ec_enter_noirq(ec);
2098 
2099 	return 0;
2100 }
2101 
acpi_ec_resume_noirq(struct device * dev)2102 static int acpi_ec_resume_noirq(struct device *dev)
2103 {
2104 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2105 
2106 	acpi_ec_leave_noirq(ec);
2107 
2108 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2109 	    ec->gpe >= 0 && ec->reference_count >= 1)
2110 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2111 
2112 	return 0;
2113 }
2114 
acpi_ec_resume(struct device * dev)2115 static int acpi_ec_resume(struct device *dev)
2116 {
2117 	struct acpi_ec *ec =
2118 		acpi_driver_data(to_acpi_device(dev));
2119 
2120 	acpi_ec_enable_event(ec);
2121 	return 0;
2122 }
2123 
acpi_ec_mark_gpe_for_wake(void)2124 void acpi_ec_mark_gpe_for_wake(void)
2125 {
2126 	if (first_ec && !ec_no_wakeup)
2127 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2128 }
2129 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2130 
acpi_ec_set_gpe_wake_mask(u8 action)2131 void acpi_ec_set_gpe_wake_mask(u8 action)
2132 {
2133 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2134 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2135 }
2136 
acpi_ec_work_in_progress(struct acpi_ec * ec)2137 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2138 {
2139 	return ec->events_in_progress + ec->queries_in_progress > 0;
2140 }
2141 
acpi_ec_dispatch_gpe(void)2142 bool acpi_ec_dispatch_gpe(void)
2143 {
2144 	bool work_in_progress = false;
2145 
2146 	if (!first_ec)
2147 		return acpi_any_gpe_status_set(U32_MAX);
2148 
2149 	/*
2150 	 * Report wakeup if the status bit is set for any enabled GPE other
2151 	 * than the EC one.
2152 	 */
2153 	if (acpi_any_gpe_status_set(first_ec->gpe))
2154 		return true;
2155 
2156 	/*
2157 	 * Cancel the SCI wakeup and process all pending events in case there
2158 	 * are any wakeup ones in there.
2159 	 *
2160 	 * Note that if any non-EC GPEs are active at this point, the SCI will
2161 	 * retrigger after the rearming in acpi_s2idle_wake(), so no events
2162 	 * should be missed by canceling the wakeup here.
2163 	 */
2164 	pm_system_cancel_wakeup();
2165 
2166 	/*
2167 	 * Dispatch the EC GPE in-band, but do not report wakeup in any case
2168 	 * to allow the caller to process events properly after that.
2169 	 */
2170 	spin_lock_irq(&first_ec->lock);
2171 
2172 	if (acpi_ec_gpe_status_set(first_ec)) {
2173 		pm_pr_dbg("ACPI EC GPE status set\n");
2174 
2175 		clear_gpe_and_advance_transaction(first_ec, false);
2176 		work_in_progress = acpi_ec_work_in_progress(first_ec);
2177 	}
2178 
2179 	spin_unlock_irq(&first_ec->lock);
2180 
2181 	if (!work_in_progress)
2182 		return false;
2183 
2184 	pm_pr_dbg("ACPI EC GPE dispatched\n");
2185 
2186 	/* Drain EC work. */
2187 	do {
2188 		acpi_ec_flush_work();
2189 
2190 		pm_pr_dbg("ACPI EC work flushed\n");
2191 
2192 		spin_lock_irq(&first_ec->lock);
2193 
2194 		work_in_progress = acpi_ec_work_in_progress(first_ec);
2195 
2196 		spin_unlock_irq(&first_ec->lock);
2197 	} while (work_in_progress && !pm_wakeup_pending());
2198 
2199 	return false;
2200 }
2201 #endif /* CONFIG_PM_SLEEP */
2202 
2203 static const struct dev_pm_ops acpi_ec_pm = {
2204 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2205 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2206 };
2207 
param_set_event_clearing(const char * val,const struct kernel_param * kp)2208 static int param_set_event_clearing(const char *val,
2209 				    const struct kernel_param *kp)
2210 {
2211 	int result = 0;
2212 
2213 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2214 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2215 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2216 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2217 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2218 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2219 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2220 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2221 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2222 	} else
2223 		result = -EINVAL;
2224 	return result;
2225 }
2226 
param_get_event_clearing(char * buffer,const struct kernel_param * kp)2227 static int param_get_event_clearing(char *buffer,
2228 				    const struct kernel_param *kp)
2229 {
2230 	switch (ec_event_clearing) {
2231 	case ACPI_EC_EVT_TIMING_STATUS:
2232 		return sprintf(buffer, "status\n");
2233 	case ACPI_EC_EVT_TIMING_QUERY:
2234 		return sprintf(buffer, "query\n");
2235 	case ACPI_EC_EVT_TIMING_EVENT:
2236 		return sprintf(buffer, "event\n");
2237 	default:
2238 		return sprintf(buffer, "invalid\n");
2239 	}
2240 	return 0;
2241 }
2242 
2243 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2244 		  NULL, 0644);
2245 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2246 
2247 static struct acpi_driver acpi_ec_driver = {
2248 	.name = "ec",
2249 	.class = ACPI_EC_CLASS,
2250 	.ids = ec_device_ids,
2251 	.ops = {
2252 		.add = acpi_ec_add,
2253 		.remove = acpi_ec_remove,
2254 		},
2255 	.drv.pm = &acpi_ec_pm,
2256 };
2257 
acpi_ec_destroy_workqueues(void)2258 static void acpi_ec_destroy_workqueues(void)
2259 {
2260 	if (ec_wq) {
2261 		destroy_workqueue(ec_wq);
2262 		ec_wq = NULL;
2263 	}
2264 	if (ec_query_wq) {
2265 		destroy_workqueue(ec_query_wq);
2266 		ec_query_wq = NULL;
2267 	}
2268 }
2269 
acpi_ec_init_workqueues(void)2270 static int acpi_ec_init_workqueues(void)
2271 {
2272 	if (!ec_wq)
2273 		ec_wq = alloc_ordered_workqueue("kec", 0);
2274 
2275 	if (!ec_query_wq)
2276 		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2277 
2278 	if (!ec_wq || !ec_query_wq) {
2279 		acpi_ec_destroy_workqueues();
2280 		return -ENODEV;
2281 	}
2282 	return 0;
2283 }
2284 
2285 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2286 	{
2287 		.matches = {
2288 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2289 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2290 		},
2291 	},
2292 	{
2293 		.matches = {
2294 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2295 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2296 		},
2297 	},
2298 	{
2299 		.matches = {
2300 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2301 			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2302 		},
2303 	},
2304 	{ },
2305 };
2306 
acpi_ec_init(void)2307 void __init acpi_ec_init(void)
2308 {
2309 	int result;
2310 
2311 	result = acpi_ec_init_workqueues();
2312 	if (result)
2313 		return;
2314 
2315 	/*
2316 	 * Disable EC wakeup on following systems to prevent periodic
2317 	 * wakeup from EC GPE.
2318 	 */
2319 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2320 		ec_no_wakeup = true;
2321 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2322 	}
2323 
2324 	/* Driver must be registered after acpi_ec_init_workqueues(). */
2325 	acpi_bus_register_driver(&acpi_ec_driver);
2326 
2327 	acpi_ec_ecdt_start();
2328 }
2329 
2330 /* EC driver currently not unloadable */
2331 #if 0
2332 static void __exit acpi_ec_exit(void)
2333 {
2334 
2335 	acpi_bus_unregister_driver(&acpi_ec_driver);
2336 	acpi_ec_destroy_workqueues();
2337 }
2338 #endif	/* 0 */
2339