Merge tag 'pm-extra-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[muen/linux.git] / drivers / acpi / ec.c
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v3)
3  *
4  *  Copyright (C) 2001-2015 Intel Corporation
5  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
6  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
7  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
8  *            2004       Luming Yu <luming.yu@intel.com>
9  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
10  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
11  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
12  *
13  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
14  *
15  *  This program is free software; you can redistribute it and/or modify
16  *  it under the terms of the GNU General Public License as published by
17  *  the Free Software Foundation; either version 2 of the License, or (at
18  *  your option) any later version.
19  *
20  *  This program is distributed in the hope that it will be useful, but
21  *  WITHOUT ANY WARRANTY; without even the implied warranty of
22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23  *  General Public License for more details.
24  *
25  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
26  */
27
28 /* Uncomment next line to get verbose printout */
29 /* #define DEBUG */
30 #define pr_fmt(fmt) "ACPI : EC: " fmt
31
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/init.h>
35 #include <linux/types.h>
36 #include <linux/delay.h>
37 #include <linux/interrupt.h>
38 #include <linux/list.h>
39 #include <linux/spinlock.h>
40 #include <linux/slab.h>
41 #include <linux/acpi.h>
42 #include <linux/dmi.h>
43 #include <asm/io.h>
44
45 #include "internal.h"
46
47 #define ACPI_EC_CLASS                   "embedded_controller"
48 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
49 #define ACPI_EC_FILE_INFO               "info"
50
51 /* EC status register */
52 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
53 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
54 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
55 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
56 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
57
58 /*
59  * The SCI_EVT clearing timing is not defined by the ACPI specification.
60  * This leads to lots of practical timing issues for the host EC driver.
61  * The following variations are defined (from the target EC firmware's
62  * perspective):
63  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
64  *         target can clear SCI_EVT at any time so long as the host can see
65  *         the indication by reading the status register (EC_SC). So the
66  *         host should re-check SCI_EVT after the first time the SCI_EVT
67  *         indication is seen, which is the same time the query request
68  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
69  *         at any later time could indicate another event. Normally such
70  *         kind of EC firmware has implemented an event queue and will
71  *         return 0x00 to indicate "no outstanding event".
72  * QUERY: After seeing the query request (QR_EC) written to the command
73  *        register (EC_CMD) by the host and having prepared the responding
74  *        event value in the data register (EC_DATA), the target can safely
75  *        clear SCI_EVT because the target can confirm that the current
76  *        event is being handled by the host. The host then should check
77  *        SCI_EVT right after reading the event response from the data
78  *        register (EC_DATA).
79  * EVENT: After seeing the event response read from the data register
80  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
81  *        target requires time to notice the change in the data register
82  *        (EC_DATA), the host may be required to wait additional guarding
83  *        time before checking the SCI_EVT again. Such guarding may not be
84  *        necessary if the host is notified via another IRQ.
85  */
86 #define ACPI_EC_EVT_TIMING_STATUS       0x00
87 #define ACPI_EC_EVT_TIMING_QUERY        0x01
88 #define ACPI_EC_EVT_TIMING_EVENT        0x02
89
90 /* EC commands */
91 enum ec_command {
92         ACPI_EC_COMMAND_READ = 0x80,
93         ACPI_EC_COMMAND_WRITE = 0x81,
94         ACPI_EC_BURST_ENABLE = 0x82,
95         ACPI_EC_BURST_DISABLE = 0x83,
96         ACPI_EC_COMMAND_QUERY = 0x84,
97 };
98
99 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
100 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
101 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
102 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
103                                          * when trying to clear the EC */
104 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
105
106 enum {
107         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
108         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
109         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
110         EC_FLAGS_GPE_HANDLER_INSTALLED, /* GPE handler installed */
111         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
112         EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
113         EC_FLAGS_STARTED,               /* Driver is started */
114         EC_FLAGS_STOPPED,               /* Driver is stopped */
115         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
116                                          * current command processing */
117 };
118
119 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
120 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
121
122 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
123 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
124 module_param(ec_delay, uint, 0644);
125 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
126
127 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
128 module_param(ec_max_queries, uint, 0644);
129 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
130
131 static bool ec_busy_polling __read_mostly;
132 module_param(ec_busy_polling, bool, 0644);
133 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
134
135 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
136 module_param(ec_polling_guard, uint, 0644);
137 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
138
139 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
140
141 /*
142  * If the number of false interrupts per one transaction exceeds
143  * this threshold, will think there is a GPE storm happened and
144  * will disable the GPE for normal transaction.
145  */
146 static unsigned int ec_storm_threshold  __read_mostly = 8;
147 module_param(ec_storm_threshold, uint, 0644);
148 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
149
150 static bool ec_freeze_events __read_mostly = true;
151 module_param(ec_freeze_events, bool, 0644);
152 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
153
154 struct acpi_ec_query_handler {
155         struct list_head node;
156         acpi_ec_query_func func;
157         acpi_handle handle;
158         void *data;
159         u8 query_bit;
160         struct kref kref;
161 };
162
163 struct transaction {
164         const u8 *wdata;
165         u8 *rdata;
166         unsigned short irq_count;
167         u8 command;
168         u8 wi;
169         u8 ri;
170         u8 wlen;
171         u8 rlen;
172         u8 flags;
173 };
174
175 struct acpi_ec_query {
176         struct transaction transaction;
177         struct work_struct work;
178         struct acpi_ec_query_handler *handler;
179 };
180
181 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
182 static void advance_transaction(struct acpi_ec *ec);
183 static void acpi_ec_event_handler(struct work_struct *work);
184 static void acpi_ec_event_processor(struct work_struct *work);
185
186 struct acpi_ec *boot_ec, *first_ec;
187 EXPORT_SYMBOL(first_ec);
188 static bool boot_ec_is_ecdt = false;
189 static struct workqueue_struct *ec_query_wq;
190
191 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
192 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
193 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
194
195 /* --------------------------------------------------------------------------
196  *                           Logging/Debugging
197  * -------------------------------------------------------------------------- */
198
199 /*
200  * Splitters used by the developers to track the boundary of the EC
201  * handling processes.
202  */
203 #ifdef DEBUG
204 #define EC_DBG_SEP      " "
205 #define EC_DBG_DRV      "+++++"
206 #define EC_DBG_STM      "====="
207 #define EC_DBG_REQ      "*****"
208 #define EC_DBG_EVT      "#####"
209 #else
210 #define EC_DBG_SEP      ""
211 #define EC_DBG_DRV
212 #define EC_DBG_STM
213 #define EC_DBG_REQ
214 #define EC_DBG_EVT
215 #endif
216
217 #define ec_log_raw(fmt, ...) \
218         pr_info(fmt "\n", ##__VA_ARGS__)
219 #define ec_dbg_raw(fmt, ...) \
220         pr_debug(fmt "\n", ##__VA_ARGS__)
221 #define ec_log(filter, fmt, ...) \
222         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
223 #define ec_dbg(filter, fmt, ...) \
224         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
225
226 #define ec_log_drv(fmt, ...) \
227         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
228 #define ec_dbg_drv(fmt, ...) \
229         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
230 #define ec_dbg_stm(fmt, ...) \
231         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
232 #define ec_dbg_req(fmt, ...) \
233         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
234 #define ec_dbg_evt(fmt, ...) \
235         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
236 #define ec_dbg_ref(ec, fmt, ...) \
237         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
238
239 /* --------------------------------------------------------------------------
240  *                           Device Flags
241  * -------------------------------------------------------------------------- */
242
243 static bool acpi_ec_started(struct acpi_ec *ec)
244 {
245         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
246                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
247 }
248
249 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
250 {
251         /*
252          * There is an OSPM early stage logic. During the early stages
253          * (boot/resume), OSPMs shouldn't enable the event handling, only
254          * the EC transactions are allowed to be performed.
255          */
256         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
257                 return false;
258         /*
259          * However, disabling the event handling is experimental for late
260          * stage (suspend), and is controlled by the boot parameter of
261          * "ec_freeze_events":
262          * 1. true:  The EC event handling is disabled before entering
263          *           the noirq stage.
264          * 2. false: The EC event handling is automatically disabled as
265          *           soon as the EC driver is stopped.
266          */
267         if (ec_freeze_events)
268                 return acpi_ec_started(ec);
269         else
270                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
271 }
272
273 static bool acpi_ec_flushed(struct acpi_ec *ec)
274 {
275         return ec->reference_count == 1;
276 }
277
278 /* --------------------------------------------------------------------------
279  *                           EC Registers
280  * -------------------------------------------------------------------------- */
281
282 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
283 {
284         u8 x = inb(ec->command_addr);
285
286         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
287                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
288                    x,
289                    !!(x & ACPI_EC_FLAG_SCI),
290                    !!(x & ACPI_EC_FLAG_BURST),
291                    !!(x & ACPI_EC_FLAG_CMD),
292                    !!(x & ACPI_EC_FLAG_IBF),
293                    !!(x & ACPI_EC_FLAG_OBF));
294         return x;
295 }
296
297 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
298 {
299         u8 x = inb(ec->data_addr);
300
301         ec->timestamp = jiffies;
302         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
303         return x;
304 }
305
306 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
307 {
308         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
309         outb(command, ec->command_addr);
310         ec->timestamp = jiffies;
311 }
312
313 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
314 {
315         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
316         outb(data, ec->data_addr);
317         ec->timestamp = jiffies;
318 }
319
320 #ifdef DEBUG
321 static const char *acpi_ec_cmd_string(u8 cmd)
322 {
323         switch (cmd) {
324         case 0x80:
325                 return "RD_EC";
326         case 0x81:
327                 return "WR_EC";
328         case 0x82:
329                 return "BE_EC";
330         case 0x83:
331                 return "BD_EC";
332         case 0x84:
333                 return "QR_EC";
334         }
335         return "UNKNOWN";
336 }
337 #else
338 #define acpi_ec_cmd_string(cmd)         "UNDEF"
339 #endif
340
341 /* --------------------------------------------------------------------------
342  *                           GPE Registers
343  * -------------------------------------------------------------------------- */
344
345 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
346 {
347         acpi_event_status gpe_status = 0;
348
349         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
350         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
351 }
352
353 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
354 {
355         if (open)
356                 acpi_enable_gpe(NULL, ec->gpe);
357         else {
358                 BUG_ON(ec->reference_count < 1);
359                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
360         }
361         if (acpi_ec_is_gpe_raised(ec)) {
362                 /*
363                  * On some platforms, EN=1 writes cannot trigger GPE. So
364                  * software need to manually trigger a pseudo GPE event on
365                  * EN=1 writes.
366                  */
367                 ec_dbg_raw("Polling quirk");
368                 advance_transaction(ec);
369         }
370 }
371
372 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
373 {
374         if (close)
375                 acpi_disable_gpe(NULL, ec->gpe);
376         else {
377                 BUG_ON(ec->reference_count < 1);
378                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
379         }
380 }
381
382 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
383 {
384         /*
385          * GPE STS is a W1C register, which means:
386          * 1. Software can clear it without worrying about clearing other
387          *    GPEs' STS bits when the hardware sets them in parallel.
388          * 2. As long as software can ensure only clearing it when it is
389          *    set, hardware won't set it in parallel.
390          * So software can clear GPE in any contexts.
391          * Warning: do not move the check into advance_transaction() as the
392          * EC commands will be sent without GPE raised.
393          */
394         if (!acpi_ec_is_gpe_raised(ec))
395                 return;
396         acpi_clear_gpe(NULL, ec->gpe);
397 }
398
399 /* --------------------------------------------------------------------------
400  *                           Transaction Management
401  * -------------------------------------------------------------------------- */
402
403 static void acpi_ec_submit_request(struct acpi_ec *ec)
404 {
405         ec->reference_count++;
406         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
407             ec->reference_count == 1)
408                 acpi_ec_enable_gpe(ec, true);
409 }
410
411 static void acpi_ec_complete_request(struct acpi_ec *ec)
412 {
413         bool flushed = false;
414
415         ec->reference_count--;
416         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
417             ec->reference_count == 0)
418                 acpi_ec_disable_gpe(ec, true);
419         flushed = acpi_ec_flushed(ec);
420         if (flushed)
421                 wake_up(&ec->wait);
422 }
423
424 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
425 {
426         if (!test_bit(flag, &ec->flags)) {
427                 acpi_ec_disable_gpe(ec, false);
428                 ec_dbg_drv("Polling enabled");
429                 set_bit(flag, &ec->flags);
430         }
431 }
432
433 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
434 {
435         if (test_bit(flag, &ec->flags)) {
436                 clear_bit(flag, &ec->flags);
437                 acpi_ec_enable_gpe(ec, false);
438                 ec_dbg_drv("Polling disabled");
439         }
440 }
441
442 /*
443  * acpi_ec_submit_flushable_request() - Increase the reference count unless
444  *                                      the flush operation is not in
445  *                                      progress
446  * @ec: the EC device
447  *
448  * This function must be used before taking a new action that should hold
449  * the reference count.  If this function returns false, then the action
450  * must be discarded or it will prevent the flush operation from being
451  * completed.
452  */
453 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
454 {
455         if (!acpi_ec_started(ec))
456                 return false;
457         acpi_ec_submit_request(ec);
458         return true;
459 }
460
461 static void acpi_ec_submit_query(struct acpi_ec *ec)
462 {
463         if (acpi_ec_event_enabled(ec) &&
464             !test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
465                 ec_dbg_evt("Command(%s) submitted/blocked",
466                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
467                 ec->nr_pending_queries++;
468                 schedule_work(&ec->work);
469         }
470 }
471
472 static void acpi_ec_complete_query(struct acpi_ec *ec)
473 {
474         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
475                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
476                 ec_dbg_evt("Command(%s) unblocked",
477                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
478         }
479 }
480
481 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
482 {
483         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
484                 ec_log_drv("event unblocked");
485         if (!test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
486                 advance_transaction(ec);
487 }
488
489 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
490 {
491         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
492                 ec_log_drv("event blocked");
493 }
494
495 /*
496  * Process _Q events that might have accumulated in the EC.
497  * Run with locked ec mutex.
498  */
499 static void acpi_ec_clear(struct acpi_ec *ec)
500 {
501         int i, status;
502         u8 value = 0;
503
504         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
505                 status = acpi_ec_query(ec, &value);
506                 if (status || !value)
507                         break;
508         }
509         if (unlikely(i == ACPI_EC_CLEAR_MAX))
510                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
511         else
512                 pr_info("%d stale EC events cleared\n", i);
513 }
514
515 static void acpi_ec_enable_event(struct acpi_ec *ec)
516 {
517         unsigned long flags;
518
519         spin_lock_irqsave(&ec->lock, flags);
520         if (acpi_ec_started(ec))
521                 __acpi_ec_enable_event(ec);
522         spin_unlock_irqrestore(&ec->lock, flags);
523
524         /* Drain additional events if hardware requires that */
525         if (EC_FLAGS_CLEAR_ON_RESUME)
526                 acpi_ec_clear(ec);
527 }
528
529 static bool acpi_ec_query_flushed(struct acpi_ec *ec)
530 {
531         bool flushed;
532         unsigned long flags;
533
534         spin_lock_irqsave(&ec->lock, flags);
535         flushed = !ec->nr_pending_queries;
536         spin_unlock_irqrestore(&ec->lock, flags);
537         return flushed;
538 }
539
540 static void __acpi_ec_flush_event(struct acpi_ec *ec)
541 {
542         /*
543          * When ec_freeze_events is true, we need to flush events in
544          * the proper position before entering the noirq stage.
545          */
546         wait_event(ec->wait, acpi_ec_query_flushed(ec));
547         if (ec_query_wq)
548                 flush_workqueue(ec_query_wq);
549 }
550
551 static void acpi_ec_disable_event(struct acpi_ec *ec)
552 {
553         unsigned long flags;
554
555         spin_lock_irqsave(&ec->lock, flags);
556         __acpi_ec_disable_event(ec);
557         spin_unlock_irqrestore(&ec->lock, flags);
558         __acpi_ec_flush_event(ec);
559 }
560
561 static bool acpi_ec_guard_event(struct acpi_ec *ec)
562 {
563         bool guarded = true;
564         unsigned long flags;
565
566         spin_lock_irqsave(&ec->lock, flags);
567         /*
568          * If firmware SCI_EVT clearing timing is "event", we actually
569          * don't know when the SCI_EVT will be cleared by firmware after
570          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
571          * acceptable period.
572          *
573          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
574          * flagged, which means SCI_EVT check has just been performed.
575          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
576          * guarding should have already been performed (via
577          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
578          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
579          * ACPI_EC_COMMAND_POLL state immediately.
580          */
581         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
582             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
583             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
584             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
585                 guarded = false;
586         spin_unlock_irqrestore(&ec->lock, flags);
587         return guarded;
588 }
589
590 static int ec_transaction_polled(struct acpi_ec *ec)
591 {
592         unsigned long flags;
593         int ret = 0;
594
595         spin_lock_irqsave(&ec->lock, flags);
596         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
597                 ret = 1;
598         spin_unlock_irqrestore(&ec->lock, flags);
599         return ret;
600 }
601
602 static int ec_transaction_completed(struct acpi_ec *ec)
603 {
604         unsigned long flags;
605         int ret = 0;
606
607         spin_lock_irqsave(&ec->lock, flags);
608         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
609                 ret = 1;
610         spin_unlock_irqrestore(&ec->lock, flags);
611         return ret;
612 }
613
614 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
615 {
616         ec->curr->flags |= flag;
617         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
618                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
619                     flag == ACPI_EC_COMMAND_POLL)
620                         acpi_ec_complete_query(ec);
621                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
622                     flag == ACPI_EC_COMMAND_COMPLETE)
623                         acpi_ec_complete_query(ec);
624                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
625                     flag == ACPI_EC_COMMAND_COMPLETE)
626                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
627         }
628 }
629
630 static void advance_transaction(struct acpi_ec *ec)
631 {
632         struct transaction *t;
633         u8 status;
634         bool wakeup = false;
635
636         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
637                    smp_processor_id());
638         /*
639          * By always clearing STS before handling all indications, we can
640          * ensure a hardware STS 0->1 change after this clearing can always
641          * trigger a GPE interrupt.
642          */
643         acpi_ec_clear_gpe(ec);
644         status = acpi_ec_read_status(ec);
645         t = ec->curr;
646         /*
647          * Another IRQ or a guarded polling mode advancement is detected,
648          * the next QR_EC submission is then allowed.
649          */
650         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
651                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
652                     (!ec->nr_pending_queries ||
653                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
654                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
655                         acpi_ec_complete_query(ec);
656                 }
657         }
658         if (!t)
659                 goto err;
660         if (t->flags & ACPI_EC_COMMAND_POLL) {
661                 if (t->wlen > t->wi) {
662                         if ((status & ACPI_EC_FLAG_IBF) == 0)
663                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
664                         else
665                                 goto err;
666                 } else if (t->rlen > t->ri) {
667                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
668                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
669                                 if (t->rlen == t->ri) {
670                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
671                                         if (t->command == ACPI_EC_COMMAND_QUERY)
672                                                 ec_dbg_evt("Command(%s) completed by hardware",
673                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
674                                         wakeup = true;
675                                 }
676                         } else
677                                 goto err;
678                 } else if (t->wlen == t->wi &&
679                            (status & ACPI_EC_FLAG_IBF) == 0) {
680                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
681                         wakeup = true;
682                 }
683                 goto out;
684         } else {
685                 if (EC_FLAGS_QUERY_HANDSHAKE &&
686                     !(status & ACPI_EC_FLAG_SCI) &&
687                     (t->command == ACPI_EC_COMMAND_QUERY)) {
688                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
689                         t->rdata[t->ri++] = 0x00;
690                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
691                         ec_dbg_evt("Command(%s) completed by software",
692                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
693                         wakeup = true;
694                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
695                         acpi_ec_write_cmd(ec, t->command);
696                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
697                 } else
698                         goto err;
699                 goto out;
700         }
701 err:
702         /*
703          * If SCI bit is set, then don't think it's a false IRQ
704          * otherwise will take a not handled IRQ as a false one.
705          */
706         if (!(status & ACPI_EC_FLAG_SCI)) {
707                 if (in_interrupt() && t) {
708                         if (t->irq_count < ec_storm_threshold)
709                                 ++t->irq_count;
710                         /* Allow triggering on 0 threshold */
711                         if (t->irq_count == ec_storm_threshold)
712                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
713                 }
714         }
715 out:
716         if (status & ACPI_EC_FLAG_SCI)
717                 acpi_ec_submit_query(ec);
718         if (wakeup && in_interrupt())
719                 wake_up(&ec->wait);
720 }
721
722 static void start_transaction(struct acpi_ec *ec)
723 {
724         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
725         ec->curr->flags = 0;
726 }
727
728 static int ec_guard(struct acpi_ec *ec)
729 {
730         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
731         unsigned long timeout = ec->timestamp + guard;
732
733         /* Ensure guarding period before polling EC status */
734         do {
735                 if (ec_busy_polling) {
736                         /* Perform busy polling */
737                         if (ec_transaction_completed(ec))
738                                 return 0;
739                         udelay(jiffies_to_usecs(guard));
740                 } else {
741                         /*
742                          * Perform wait polling
743                          * 1. Wait the transaction to be completed by the
744                          *    GPE handler after the transaction enters
745                          *    ACPI_EC_COMMAND_POLL state.
746                          * 2. A special guarding logic is also required
747                          *    for event clearing mode "event" before the
748                          *    transaction enters ACPI_EC_COMMAND_POLL
749                          *    state.
750                          */
751                         if (!ec_transaction_polled(ec) &&
752                             !acpi_ec_guard_event(ec))
753                                 break;
754                         if (wait_event_timeout(ec->wait,
755                                                ec_transaction_completed(ec),
756                                                guard))
757                                 return 0;
758                 }
759         } while (time_before(jiffies, timeout));
760         return -ETIME;
761 }
762
763 static int ec_poll(struct acpi_ec *ec)
764 {
765         unsigned long flags;
766         int repeat = 5; /* number of command restarts */
767
768         while (repeat--) {
769                 unsigned long delay = jiffies +
770                         msecs_to_jiffies(ec_delay);
771                 do {
772                         if (!ec_guard(ec))
773                                 return 0;
774                         spin_lock_irqsave(&ec->lock, flags);
775                         advance_transaction(ec);
776                         spin_unlock_irqrestore(&ec->lock, flags);
777                 } while (time_before(jiffies, delay));
778                 pr_debug("controller reset, restart transaction\n");
779                 spin_lock_irqsave(&ec->lock, flags);
780                 start_transaction(ec);
781                 spin_unlock_irqrestore(&ec->lock, flags);
782         }
783         return -ETIME;
784 }
785
786 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
787                                         struct transaction *t)
788 {
789         unsigned long tmp;
790         int ret = 0;
791
792         /* start transaction */
793         spin_lock_irqsave(&ec->lock, tmp);
794         /* Enable GPE for command processing (IBF=0/OBF=1) */
795         if (!acpi_ec_submit_flushable_request(ec)) {
796                 ret = -EINVAL;
797                 goto unlock;
798         }
799         ec_dbg_ref(ec, "Increase command");
800         /* following two actions should be kept atomic */
801         ec->curr = t;
802         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
803         start_transaction(ec);
804         spin_unlock_irqrestore(&ec->lock, tmp);
805
806         ret = ec_poll(ec);
807
808         spin_lock_irqsave(&ec->lock, tmp);
809         if (t->irq_count == ec_storm_threshold)
810                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
811         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
812         ec->curr = NULL;
813         /* Disable GPE for command processing (IBF=0/OBF=1) */
814         acpi_ec_complete_request(ec);
815         ec_dbg_ref(ec, "Decrease command");
816 unlock:
817         spin_unlock_irqrestore(&ec->lock, tmp);
818         return ret;
819 }
820
821 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
822 {
823         int status;
824         u32 glk;
825
826         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
827                 return -EINVAL;
828         if (t->rdata)
829                 memset(t->rdata, 0, t->rlen);
830
831         mutex_lock(&ec->mutex);
832         if (ec->global_lock) {
833                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
834                 if (ACPI_FAILURE(status)) {
835                         status = -ENODEV;
836                         goto unlock;
837                 }
838         }
839
840         status = acpi_ec_transaction_unlocked(ec, t);
841
842         if (ec->global_lock)
843                 acpi_release_global_lock(glk);
844 unlock:
845         mutex_unlock(&ec->mutex);
846         return status;
847 }
848
849 static int acpi_ec_burst_enable(struct acpi_ec *ec)
850 {
851         u8 d;
852         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
853                                 .wdata = NULL, .rdata = &d,
854                                 .wlen = 0, .rlen = 1};
855
856         return acpi_ec_transaction(ec, &t);
857 }
858
859 static int acpi_ec_burst_disable(struct acpi_ec *ec)
860 {
861         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
862                                 .wdata = NULL, .rdata = NULL,
863                                 .wlen = 0, .rlen = 0};
864
865         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
866                                 acpi_ec_transaction(ec, &t) : 0;
867 }
868
869 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
870 {
871         int result;
872         u8 d;
873         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
874                                 .wdata = &address, .rdata = &d,
875                                 .wlen = 1, .rlen = 1};
876
877         result = acpi_ec_transaction(ec, &t);
878         *data = d;
879         return result;
880 }
881
882 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
883 {
884         u8 wdata[2] = { address, data };
885         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
886                                 .wdata = wdata, .rdata = NULL,
887                                 .wlen = 2, .rlen = 0};
888
889         return acpi_ec_transaction(ec, &t);
890 }
891
892 int ec_read(u8 addr, u8 *val)
893 {
894         int err;
895         u8 temp_data;
896
897         if (!first_ec)
898                 return -ENODEV;
899
900         err = acpi_ec_read(first_ec, addr, &temp_data);
901
902         if (!err) {
903                 *val = temp_data;
904                 return 0;
905         }
906         return err;
907 }
908 EXPORT_SYMBOL(ec_read);
909
910 int ec_write(u8 addr, u8 val)
911 {
912         int err;
913
914         if (!first_ec)
915                 return -ENODEV;
916
917         err = acpi_ec_write(first_ec, addr, val);
918
919         return err;
920 }
921 EXPORT_SYMBOL(ec_write);
922
923 int ec_transaction(u8 command,
924                    const u8 *wdata, unsigned wdata_len,
925                    u8 *rdata, unsigned rdata_len)
926 {
927         struct transaction t = {.command = command,
928                                 .wdata = wdata, .rdata = rdata,
929                                 .wlen = wdata_len, .rlen = rdata_len};
930
931         if (!first_ec)
932                 return -ENODEV;
933
934         return acpi_ec_transaction(first_ec, &t);
935 }
936 EXPORT_SYMBOL(ec_transaction);
937
938 /* Get the handle to the EC device */
939 acpi_handle ec_get_handle(void)
940 {
941         if (!first_ec)
942                 return NULL;
943         return first_ec->handle;
944 }
945 EXPORT_SYMBOL(ec_get_handle);
946
947 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
948 {
949         unsigned long flags;
950
951         spin_lock_irqsave(&ec->lock, flags);
952         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
953                 ec_dbg_drv("Starting EC");
954                 /* Enable GPE for event processing (SCI_EVT=1) */
955                 if (!resuming) {
956                         acpi_ec_submit_request(ec);
957                         ec_dbg_ref(ec, "Increase driver");
958                 }
959                 ec_log_drv("EC started");
960         }
961         spin_unlock_irqrestore(&ec->lock, flags);
962 }
963
964 static bool acpi_ec_stopped(struct acpi_ec *ec)
965 {
966         unsigned long flags;
967         bool flushed;
968
969         spin_lock_irqsave(&ec->lock, flags);
970         flushed = acpi_ec_flushed(ec);
971         spin_unlock_irqrestore(&ec->lock, flags);
972         return flushed;
973 }
974
975 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
976 {
977         unsigned long flags;
978
979         spin_lock_irqsave(&ec->lock, flags);
980         if (acpi_ec_started(ec)) {
981                 ec_dbg_drv("Stopping EC");
982                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
983                 spin_unlock_irqrestore(&ec->lock, flags);
984                 wait_event(ec->wait, acpi_ec_stopped(ec));
985                 spin_lock_irqsave(&ec->lock, flags);
986                 /* Disable GPE for event processing (SCI_EVT=1) */
987                 if (!suspending) {
988                         acpi_ec_complete_request(ec);
989                         ec_dbg_ref(ec, "Decrease driver");
990                 } else if (!ec_freeze_events)
991                         __acpi_ec_disable_event(ec);
992                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
993                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
994                 ec_log_drv("EC stopped");
995         }
996         spin_unlock_irqrestore(&ec->lock, flags);
997 }
998
999 void acpi_ec_block_transactions(void)
1000 {
1001         struct acpi_ec *ec = first_ec;
1002
1003         if (!ec)
1004                 return;
1005
1006         mutex_lock(&ec->mutex);
1007         /* Prevent transactions from being carried out */
1008         acpi_ec_stop(ec, true);
1009         mutex_unlock(&ec->mutex);
1010 }
1011
1012 void acpi_ec_unblock_transactions(void)
1013 {
1014         /*
1015          * Allow transactions to happen again (this function is called from
1016          * atomic context during wakeup, so we don't need to acquire the mutex).
1017          */
1018         if (first_ec)
1019                 acpi_ec_start(first_ec, true);
1020 }
1021
1022 /* --------------------------------------------------------------------------
1023                                 Event Management
1024    -------------------------------------------------------------------------- */
1025 static struct acpi_ec_query_handler *
1026 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
1027 {
1028         if (handler)
1029                 kref_get(&handler->kref);
1030         return handler;
1031 }
1032
1033 static struct acpi_ec_query_handler *
1034 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1035 {
1036         struct acpi_ec_query_handler *handler;
1037         bool found = false;
1038
1039         mutex_lock(&ec->mutex);
1040         list_for_each_entry(handler, &ec->list, node) {
1041                 if (value == handler->query_bit) {
1042                         found = true;
1043                         break;
1044                 }
1045         }
1046         mutex_unlock(&ec->mutex);
1047         return found ? acpi_ec_get_query_handler(handler) : NULL;
1048 }
1049
1050 static void acpi_ec_query_handler_release(struct kref *kref)
1051 {
1052         struct acpi_ec_query_handler *handler =
1053                 container_of(kref, struct acpi_ec_query_handler, kref);
1054
1055         kfree(handler);
1056 }
1057
1058 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1059 {
1060         kref_put(&handler->kref, acpi_ec_query_handler_release);
1061 }
1062
1063 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1064                               acpi_handle handle, acpi_ec_query_func func,
1065                               void *data)
1066 {
1067         struct acpi_ec_query_handler *handler =
1068             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1069
1070         if (!handler)
1071                 return -ENOMEM;
1072
1073         handler->query_bit = query_bit;
1074         handler->handle = handle;
1075         handler->func = func;
1076         handler->data = data;
1077         mutex_lock(&ec->mutex);
1078         kref_init(&handler->kref);
1079         list_add(&handler->node, &ec->list);
1080         mutex_unlock(&ec->mutex);
1081         return 0;
1082 }
1083 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1084
1085 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1086                                           bool remove_all, u8 query_bit)
1087 {
1088         struct acpi_ec_query_handler *handler, *tmp;
1089         LIST_HEAD(free_list);
1090
1091         mutex_lock(&ec->mutex);
1092         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1093                 if (remove_all || query_bit == handler->query_bit) {
1094                         list_del_init(&handler->node);
1095                         list_add(&handler->node, &free_list);
1096                 }
1097         }
1098         mutex_unlock(&ec->mutex);
1099         list_for_each_entry_safe(handler, tmp, &free_list, node)
1100                 acpi_ec_put_query_handler(handler);
1101 }
1102
1103 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1104 {
1105         acpi_ec_remove_query_handlers(ec, false, query_bit);
1106 }
1107 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1108
1109 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1110 {
1111         struct acpi_ec_query *q;
1112         struct transaction *t;
1113
1114         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1115         if (!q)
1116                 return NULL;
1117         INIT_WORK(&q->work, acpi_ec_event_processor);
1118         t = &q->transaction;
1119         t->command = ACPI_EC_COMMAND_QUERY;
1120         t->rdata = pval;
1121         t->rlen = 1;
1122         return q;
1123 }
1124
1125 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1126 {
1127         if (q) {
1128                 if (q->handler)
1129                         acpi_ec_put_query_handler(q->handler);
1130                 kfree(q);
1131         }
1132 }
1133
1134 static void acpi_ec_event_processor(struct work_struct *work)
1135 {
1136         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1137         struct acpi_ec_query_handler *handler = q->handler;
1138
1139         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1140         if (handler->func)
1141                 handler->func(handler->data);
1142         else if (handler->handle)
1143                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1144         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1145         acpi_ec_delete_query(q);
1146 }
1147
1148 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1149 {
1150         u8 value = 0;
1151         int result;
1152         struct acpi_ec_query *q;
1153
1154         q = acpi_ec_create_query(&value);
1155         if (!q)
1156                 return -ENOMEM;
1157
1158         /*
1159          * Query the EC to find out which _Qxx method we need to evaluate.
1160          * Note that successful completion of the query causes the ACPI_EC_SCI
1161          * bit to be cleared (and thus clearing the interrupt source).
1162          */
1163         result = acpi_ec_transaction(ec, &q->transaction);
1164         if (!value)
1165                 result = -ENODATA;
1166         if (result)
1167                 goto err_exit;
1168
1169         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1170         if (!q->handler) {
1171                 result = -ENODATA;
1172                 goto err_exit;
1173         }
1174
1175         /*
1176          * It is reported that _Qxx are evaluated in a parallel way on
1177          * Windows:
1178          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1179          *
1180          * Put this log entry before schedule_work() in order to make
1181          * it appearing before any other log entries occurred during the
1182          * work queue execution.
1183          */
1184         ec_dbg_evt("Query(0x%02x) scheduled", value);
1185         if (!queue_work(ec_query_wq, &q->work)) {
1186                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1187                 result = -EBUSY;
1188         }
1189
1190 err_exit:
1191         if (result)
1192                 acpi_ec_delete_query(q);
1193         if (data)
1194                 *data = value;
1195         return result;
1196 }
1197
1198 static void acpi_ec_check_event(struct acpi_ec *ec)
1199 {
1200         unsigned long flags;
1201
1202         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1203                 if (ec_guard(ec)) {
1204                         spin_lock_irqsave(&ec->lock, flags);
1205                         /*
1206                          * Take care of the SCI_EVT unless no one else is
1207                          * taking care of it.
1208                          */
1209                         if (!ec->curr)
1210                                 advance_transaction(ec);
1211                         spin_unlock_irqrestore(&ec->lock, flags);
1212                 }
1213         }
1214 }
1215
1216 static void acpi_ec_event_handler(struct work_struct *work)
1217 {
1218         unsigned long flags;
1219         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1220
1221         ec_dbg_evt("Event started");
1222
1223         spin_lock_irqsave(&ec->lock, flags);
1224         while (ec->nr_pending_queries) {
1225                 spin_unlock_irqrestore(&ec->lock, flags);
1226                 (void)acpi_ec_query(ec, NULL);
1227                 spin_lock_irqsave(&ec->lock, flags);
1228                 ec->nr_pending_queries--;
1229                 /*
1230                  * Before exit, make sure that this work item can be
1231                  * scheduled again. There might be QR_EC failures, leaving
1232                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1233                  * item from being scheduled again.
1234                  */
1235                 if (!ec->nr_pending_queries) {
1236                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1237                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1238                                 acpi_ec_complete_query(ec);
1239                 }
1240         }
1241         spin_unlock_irqrestore(&ec->lock, flags);
1242
1243         ec_dbg_evt("Event stopped");
1244
1245         acpi_ec_check_event(ec);
1246 }
1247
1248 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1249         u32 gpe_number, void *data)
1250 {
1251         unsigned long flags;
1252         struct acpi_ec *ec = data;
1253
1254         spin_lock_irqsave(&ec->lock, flags);
1255         advance_transaction(ec);
1256         spin_unlock_irqrestore(&ec->lock, flags);
1257         return ACPI_INTERRUPT_HANDLED;
1258 }
1259
1260 /* --------------------------------------------------------------------------
1261  *                           Address Space Management
1262  * -------------------------------------------------------------------------- */
1263
1264 static acpi_status
1265 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1266                       u32 bits, u64 *value64,
1267                       void *handler_context, void *region_context)
1268 {
1269         struct acpi_ec *ec = handler_context;
1270         int result = 0, i, bytes = bits / 8;
1271         u8 *value = (u8 *)value64;
1272
1273         if ((address > 0xFF) || !value || !handler_context)
1274                 return AE_BAD_PARAMETER;
1275
1276         if (function != ACPI_READ && function != ACPI_WRITE)
1277                 return AE_BAD_PARAMETER;
1278
1279         if (ec_busy_polling || bits > 8)
1280                 acpi_ec_burst_enable(ec);
1281
1282         for (i = 0; i < bytes; ++i, ++address, ++value)
1283                 result = (function == ACPI_READ) ?
1284                         acpi_ec_read(ec, address, value) :
1285                         acpi_ec_write(ec, address, *value);
1286
1287         if (ec_busy_polling || bits > 8)
1288                 acpi_ec_burst_disable(ec);
1289
1290         switch (result) {
1291         case -EINVAL:
1292                 return AE_BAD_PARAMETER;
1293         case -ENODEV:
1294                 return AE_NOT_FOUND;
1295         case -ETIME:
1296                 return AE_TIME;
1297         default:
1298                 return AE_OK;
1299         }
1300 }
1301
1302 /* --------------------------------------------------------------------------
1303  *                             Driver Interface
1304  * -------------------------------------------------------------------------- */
1305
1306 static acpi_status
1307 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1308
1309 static void acpi_ec_free(struct acpi_ec *ec)
1310 {
1311         if (first_ec == ec)
1312                 first_ec = NULL;
1313         if (boot_ec == ec)
1314                 boot_ec = NULL;
1315         kfree(ec);
1316 }
1317
1318 static struct acpi_ec *acpi_ec_alloc(void)
1319 {
1320         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1321
1322         if (!ec)
1323                 return NULL;
1324         mutex_init(&ec->mutex);
1325         init_waitqueue_head(&ec->wait);
1326         INIT_LIST_HEAD(&ec->list);
1327         spin_lock_init(&ec->lock);
1328         INIT_WORK(&ec->work, acpi_ec_event_handler);
1329         ec->timestamp = jiffies;
1330         return ec;
1331 }
1332
1333 static acpi_status
1334 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1335                                void *context, void **return_value)
1336 {
1337         char node_name[5];
1338         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1339         struct acpi_ec *ec = context;
1340         int value = 0;
1341         acpi_status status;
1342
1343         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1344
1345         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1346                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1347         return AE_OK;
1348 }
1349
1350 static acpi_status
1351 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1352 {
1353         acpi_status status;
1354         unsigned long long tmp = 0;
1355         struct acpi_ec *ec = context;
1356
1357         /* clear addr values, ec_parse_io_ports depend on it */
1358         ec->command_addr = ec->data_addr = 0;
1359
1360         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1361                                      ec_parse_io_ports, ec);
1362         if (ACPI_FAILURE(status))
1363                 return status;
1364
1365         /* Get GPE bit assignment (EC events). */
1366         /* TODO: Add support for _GPE returning a package */
1367         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1368         if (ACPI_FAILURE(status))
1369                 return status;
1370         ec->gpe = tmp;
1371         /* Use the global lock for all EC transactions? */
1372         tmp = 0;
1373         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1374         ec->global_lock = tmp;
1375         ec->handle = handle;
1376         return AE_CTRL_TERMINATE;
1377 }
1378
1379 /*
1380  * Note: This function returns an error code only when the address space
1381  *       handler is not installed, which means "not able to handle
1382  *       transactions".
1383  */
1384 static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1385 {
1386         acpi_status status;
1387
1388         acpi_ec_start(ec, false);
1389
1390         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1391                 status = acpi_install_address_space_handler(ec->handle,
1392                                                             ACPI_ADR_SPACE_EC,
1393                                                             &acpi_ec_space_handler,
1394                                                             NULL, ec);
1395                 if (ACPI_FAILURE(status)) {
1396                         if (status == AE_NOT_FOUND) {
1397                                 /*
1398                                  * Maybe OS fails in evaluating the _REG
1399                                  * object. The AE_NOT_FOUND error will be
1400                                  * ignored and OS * continue to initialize
1401                                  * EC.
1402                                  */
1403                                 pr_err("Fail in evaluating the _REG object"
1404                                         " of EC device. Broken bios is suspected.\n");
1405                         } else {
1406                                 acpi_ec_stop(ec, false);
1407                                 return -ENODEV;
1408                         }
1409                 }
1410                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1411         }
1412
1413         if (!handle_events)
1414                 return 0;
1415
1416         if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1417                 /* Find and register all query methods */
1418                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1419                                     acpi_ec_register_query_methods,
1420                                     NULL, ec, NULL);
1421                 set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1422         }
1423         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1424                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1425                                           ACPI_GPE_EDGE_TRIGGERED,
1426                                           &acpi_ec_gpe_handler, ec);
1427                 /* This is not fatal as we can poll EC events */
1428                 if (ACPI_SUCCESS(status)) {
1429                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1430                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1431                             ec->reference_count >= 1)
1432                                 acpi_ec_enable_gpe(ec, true);
1433
1434                         /* EC is fully operational, allow queries */
1435                         acpi_ec_enable_event(ec);
1436                 }
1437         }
1438
1439         return 0;
1440 }
1441
1442 static void ec_remove_handlers(struct acpi_ec *ec)
1443 {
1444         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1445                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1446                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1447                         pr_err("failed to remove space handler\n");
1448                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1449         }
1450
1451         /*
1452          * Stops handling the EC transactions after removing the operation
1453          * region handler. This is required because _REG(DISCONNECT)
1454          * invoked during the removal can result in new EC transactions.
1455          *
1456          * Flushes the EC requests and thus disables the GPE before
1457          * removing the GPE handler. This is required by the current ACPICA
1458          * GPE core. ACPICA GPE core will automatically disable a GPE when
1459          * it is indicated but there is no way to handle it. So the drivers
1460          * must disable the GPEs prior to removing the GPE handlers.
1461          */
1462         acpi_ec_stop(ec, false);
1463
1464         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1465                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1466                                         &acpi_ec_gpe_handler)))
1467                         pr_err("failed to remove gpe handler\n");
1468                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1469         }
1470         if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1471                 acpi_ec_remove_query_handlers(ec, true, 0);
1472                 clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1473         }
1474 }
1475
1476 static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1477 {
1478         int ret;
1479
1480         ret = ec_install_handlers(ec, handle_events);
1481         if (ret)
1482                 return ret;
1483
1484         /* First EC capable of handling transactions */
1485         if (!first_ec) {
1486                 first_ec = ec;
1487                 acpi_handle_info(first_ec->handle, "Used as first EC\n");
1488         }
1489
1490         acpi_handle_info(ec->handle,
1491                          "GPE=0x%lx, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1492                          ec->gpe, ec->command_addr, ec->data_addr);
1493         return ret;
1494 }
1495
1496 static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
1497                                bool handle_events, bool is_ecdt)
1498 {
1499         int ret;
1500
1501         /*
1502          * Changing the ACPI handle results in a re-configuration of the
1503          * boot EC. And if it happens after the namespace initialization,
1504          * it causes _REG evaluations.
1505          */
1506         if (boot_ec && boot_ec->handle != handle)
1507                 ec_remove_handlers(boot_ec);
1508
1509         /* Unset old boot EC */
1510         if (boot_ec != ec)
1511                 acpi_ec_free(boot_ec);
1512
1513         /*
1514          * ECDT device creation is split into acpi_ec_ecdt_probe() and
1515          * acpi_ec_ecdt_start(). This function takes care of completing the
1516          * ECDT parsing logic as the handle update should be performed
1517          * between the installation/uninstallation of the handlers.
1518          */
1519         if (ec->handle != handle)
1520                 ec->handle = handle;
1521
1522         ret = acpi_ec_setup(ec, handle_events);
1523         if (ret)
1524                 return ret;
1525
1526         /* Set new boot EC */
1527         if (!boot_ec) {
1528                 boot_ec = ec;
1529                 boot_ec_is_ecdt = is_ecdt;
1530         }
1531
1532         acpi_handle_info(boot_ec->handle,
1533                          "Used as boot %s EC to handle transactions%s\n",
1534                          is_ecdt ? "ECDT" : "DSDT",
1535                          handle_events ? " and events" : "");
1536         return ret;
1537 }
1538
1539 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1540 {
1541         struct acpi_table_ecdt *ecdt_ptr;
1542         acpi_status status;
1543         acpi_handle handle;
1544
1545         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1546                                 (struct acpi_table_header **)&ecdt_ptr);
1547         if (ACPI_FAILURE(status))
1548                 return false;
1549
1550         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1551         if (ACPI_FAILURE(status))
1552                 return false;
1553
1554         *phandle = handle;
1555         return true;
1556 }
1557
1558 static bool acpi_is_boot_ec(struct acpi_ec *ec)
1559 {
1560         if (!boot_ec)
1561                 return false;
1562         if (ec->handle == boot_ec->handle &&
1563             ec->gpe == boot_ec->gpe &&
1564             ec->command_addr == boot_ec->command_addr &&
1565             ec->data_addr == boot_ec->data_addr)
1566                 return true;
1567         return false;
1568 }
1569
1570 static int acpi_ec_add(struct acpi_device *device)
1571 {
1572         struct acpi_ec *ec = NULL;
1573         int ret;
1574
1575         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1576         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1577
1578         ec = acpi_ec_alloc();
1579         if (!ec)
1580                 return -ENOMEM;
1581         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1582                 AE_CTRL_TERMINATE) {
1583                         ret = -EINVAL;
1584                         goto err_alloc;
1585         }
1586
1587         if (acpi_is_boot_ec(ec)) {
1588                 boot_ec_is_ecdt = false;
1589                 acpi_handle_debug(ec->handle, "duplicated.\n");
1590                 acpi_ec_free(ec);
1591                 ec = boot_ec;
1592                 ret = acpi_config_boot_ec(ec, ec->handle, true, false);
1593         } else
1594                 ret = acpi_ec_setup(ec, true);
1595         if (ret)
1596                 goto err_query;
1597
1598         device->driver_data = ec;
1599
1600         ret = !!request_region(ec->data_addr, 1, "EC data");
1601         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1602         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1603         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1604
1605         /* Reprobe devices depending on the EC */
1606         acpi_walk_dep_device_list(ec->handle);
1607         acpi_handle_debug(ec->handle, "enumerated.\n");
1608         return 0;
1609
1610 err_query:
1611         if (ec != boot_ec)
1612                 acpi_ec_remove_query_handlers(ec, true, 0);
1613 err_alloc:
1614         if (ec != boot_ec)
1615                 acpi_ec_free(ec);
1616         return ret;
1617 }
1618
1619 static int acpi_ec_remove(struct acpi_device *device)
1620 {
1621         struct acpi_ec *ec;
1622
1623         if (!device)
1624                 return -EINVAL;
1625
1626         ec = acpi_driver_data(device);
1627         release_region(ec->data_addr, 1);
1628         release_region(ec->command_addr, 1);
1629         device->driver_data = NULL;
1630         if (ec != boot_ec) {
1631                 ec_remove_handlers(ec);
1632                 acpi_ec_free(ec);
1633         }
1634         return 0;
1635 }
1636
1637 static acpi_status
1638 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1639 {
1640         struct acpi_ec *ec = context;
1641
1642         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1643                 return AE_OK;
1644
1645         /*
1646          * The first address region returned is the data port, and
1647          * the second address region returned is the status/command
1648          * port.
1649          */
1650         if (ec->data_addr == 0)
1651                 ec->data_addr = resource->data.io.minimum;
1652         else if (ec->command_addr == 0)
1653                 ec->command_addr = resource->data.io.minimum;
1654         else
1655                 return AE_CTRL_TERMINATE;
1656
1657         return AE_OK;
1658 }
1659
1660 static const struct acpi_device_id ec_device_ids[] = {
1661         {"PNP0C09", 0},
1662         {"", 0},
1663 };
1664
1665 int __init acpi_ec_dsdt_probe(void)
1666 {
1667         acpi_status status;
1668         struct acpi_ec *ec;
1669         int ret;
1670
1671         ec = acpi_ec_alloc();
1672         if (!ec)
1673                 return -ENOMEM;
1674         /*
1675          * At this point, the namespace is initialized, so start to find
1676          * the namespace objects.
1677          */
1678         status = acpi_get_devices(ec_device_ids[0].id,
1679                                   ec_parse_device, ec, NULL);
1680         if (ACPI_FAILURE(status) || !ec->handle) {
1681                 ret = -ENODEV;
1682                 goto error;
1683         }
1684         /*
1685          * When the DSDT EC is available, always re-configure boot EC to
1686          * have _REG evaluated. _REG can only be evaluated after the
1687          * namespace initialization.
1688          * At this point, the GPE is not fully initialized, so do not to
1689          * handle the events.
1690          */
1691         ret = acpi_config_boot_ec(ec, ec->handle, false, false);
1692 error:
1693         if (ret)
1694                 acpi_ec_free(ec);
1695         return ret;
1696 }
1697
1698 /*
1699  * If the DSDT EC is not functioning, we still need to prepare a fully
1700  * functioning ECDT EC first in order to handle the events.
1701  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1702  */
1703 int __init acpi_ec_ecdt_start(void)
1704 {
1705         acpi_handle handle;
1706
1707         if (!boot_ec)
1708                 return -ENODEV;
1709         /*
1710          * The DSDT EC should have already been started in
1711          * acpi_ec_add().
1712          */
1713         if (!boot_ec_is_ecdt)
1714                 return -ENODEV;
1715
1716         /*
1717          * At this point, the namespace and the GPE is initialized, so
1718          * start to find the namespace objects and handle the events.
1719          */
1720         if (!acpi_ec_ecdt_get_handle(&handle))
1721                 return -ENODEV;
1722         return acpi_config_boot_ec(boot_ec, handle, true, true);
1723 }
1724
1725 #if 0
1726 /*
1727  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1728  * set, for which case, we complete the QR_EC without issuing it to the
1729  * firmware.
1730  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1731  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1732  */
1733 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1734 {
1735         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1736         EC_FLAGS_QUERY_HANDSHAKE = 1;
1737         return 0;
1738 }
1739 #endif
1740
1741 /*
1742  * On some hardware it is necessary to clear events accumulated by the EC during
1743  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1744  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1745  *
1746  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1747  *
1748  * Ideally, the EC should also be instructed NOT to accumulate events during
1749  * sleep (which Windows seems to do somehow), but the interface to control this
1750  * behaviour is not known at this time.
1751  *
1752  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1753  * however it is very likely that other Samsung models are affected.
1754  *
1755  * On systems which don't accumulate _Q events during sleep, this extra check
1756  * should be harmless.
1757  */
1758 static int ec_clear_on_resume(const struct dmi_system_id *id)
1759 {
1760         pr_debug("Detected system needing EC poll on resume.\n");
1761         EC_FLAGS_CLEAR_ON_RESUME = 1;
1762         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1763         return 0;
1764 }
1765
1766 /*
1767  * Some ECDTs contain wrong register addresses.
1768  * MSI MS-171F
1769  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1770  */
1771 static int ec_correct_ecdt(const struct dmi_system_id *id)
1772 {
1773         pr_debug("Detected system needing ECDT address correction.\n");
1774         EC_FLAGS_CORRECT_ECDT = 1;
1775         return 0;
1776 }
1777
1778 static struct dmi_system_id ec_dmi_table[] __initdata = {
1779         {
1780         ec_correct_ecdt, "MSI MS-171F", {
1781         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1782         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1783         {
1784         ec_clear_on_resume, "Samsung hardware", {
1785         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1786         {},
1787 };
1788
1789 int __init acpi_ec_ecdt_probe(void)
1790 {
1791         int ret;
1792         acpi_status status;
1793         struct acpi_table_ecdt *ecdt_ptr;
1794         struct acpi_ec *ec;
1795
1796         ec = acpi_ec_alloc();
1797         if (!ec)
1798                 return -ENOMEM;
1799         /*
1800          * Generate a boot ec context
1801          */
1802         dmi_check_system(ec_dmi_table);
1803         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1804                                 (struct acpi_table_header **)&ecdt_ptr);
1805         if (ACPI_FAILURE(status)) {
1806                 ret = -ENODEV;
1807                 goto error;
1808         }
1809
1810         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1811                 /*
1812                  * Asus X50GL:
1813                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1814                  */
1815                 ret = -ENODEV;
1816                 goto error;
1817         }
1818
1819         if (EC_FLAGS_CORRECT_ECDT) {
1820                 ec->command_addr = ecdt_ptr->data.address;
1821                 ec->data_addr = ecdt_ptr->control.address;
1822         } else {
1823                 ec->command_addr = ecdt_ptr->control.address;
1824                 ec->data_addr = ecdt_ptr->data.address;
1825         }
1826         ec->gpe = ecdt_ptr->gpe;
1827
1828         /*
1829          * At this point, the namespace is not initialized, so do not find
1830          * the namespace objects, or handle the events.
1831          */
1832         ret = acpi_config_boot_ec(ec, ACPI_ROOT_OBJECT, false, true);
1833 error:
1834         if (ret)
1835                 acpi_ec_free(ec);
1836         return ret;
1837 }
1838
1839 #ifdef CONFIG_PM_SLEEP
1840 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1841 {
1842         unsigned long flags;
1843
1844         if (ec == first_ec) {
1845                 spin_lock_irqsave(&ec->lock, flags);
1846                 ec->saved_busy_polling = ec_busy_polling;
1847                 ec->saved_polling_guard = ec_polling_guard;
1848                 ec_busy_polling = true;
1849                 ec_polling_guard = 0;
1850                 ec_log_drv("interrupt blocked");
1851                 spin_unlock_irqrestore(&ec->lock, flags);
1852         }
1853 }
1854
1855 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1856 {
1857         unsigned long flags;
1858
1859         if (ec == first_ec) {
1860                 spin_lock_irqsave(&ec->lock, flags);
1861                 ec_busy_polling = ec->saved_busy_polling;
1862                 ec_polling_guard = ec->saved_polling_guard;
1863                 ec_log_drv("interrupt unblocked");
1864                 spin_unlock_irqrestore(&ec->lock, flags);
1865         }
1866 }
1867
1868 static int acpi_ec_suspend_noirq(struct device *dev)
1869 {
1870         struct acpi_ec *ec =
1871                 acpi_driver_data(to_acpi_device(dev));
1872
1873         acpi_ec_enter_noirq(ec);
1874         return 0;
1875 }
1876
1877 static int acpi_ec_resume_noirq(struct device *dev)
1878 {
1879         struct acpi_ec *ec =
1880                 acpi_driver_data(to_acpi_device(dev));
1881
1882         acpi_ec_leave_noirq(ec);
1883         return 0;
1884 }
1885
1886 static int acpi_ec_suspend(struct device *dev)
1887 {
1888         struct acpi_ec *ec =
1889                 acpi_driver_data(to_acpi_device(dev));
1890
1891         if (ec_freeze_events)
1892                 acpi_ec_disable_event(ec);
1893         return 0;
1894 }
1895
1896 static int acpi_ec_resume(struct device *dev)
1897 {
1898         struct acpi_ec *ec =
1899                 acpi_driver_data(to_acpi_device(dev));
1900
1901         acpi_ec_enable_event(ec);
1902         return 0;
1903 }
1904 #endif
1905
1906 static const struct dev_pm_ops acpi_ec_pm = {
1907         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
1908         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1909 };
1910
1911 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1912 {
1913         int result = 0;
1914
1915         if (!strncmp(val, "status", sizeof("status") - 1)) {
1916                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1917                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1918         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1919                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1920                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1921         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1922                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1923                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1924         } else
1925                 result = -EINVAL;
1926         return result;
1927 }
1928
1929 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1930 {
1931         switch (ec_event_clearing) {
1932         case ACPI_EC_EVT_TIMING_STATUS:
1933                 return sprintf(buffer, "status");
1934         case ACPI_EC_EVT_TIMING_QUERY:
1935                 return sprintf(buffer, "query");
1936         case ACPI_EC_EVT_TIMING_EVENT:
1937                 return sprintf(buffer, "event");
1938         default:
1939                 return sprintf(buffer, "invalid");
1940         }
1941         return 0;
1942 }
1943
1944 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1945                   NULL, 0644);
1946 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1947
1948 static struct acpi_driver acpi_ec_driver = {
1949         .name = "ec",
1950         .class = ACPI_EC_CLASS,
1951         .ids = ec_device_ids,
1952         .ops = {
1953                 .add = acpi_ec_add,
1954                 .remove = acpi_ec_remove,
1955                 },
1956         .drv.pm = &acpi_ec_pm,
1957 };
1958
1959 static inline int acpi_ec_query_init(void)
1960 {
1961         if (!ec_query_wq) {
1962                 ec_query_wq = alloc_workqueue("kec_query", 0,
1963                                               ec_max_queries);
1964                 if (!ec_query_wq)
1965                         return -ENODEV;
1966         }
1967         return 0;
1968 }
1969
1970 static inline void acpi_ec_query_exit(void)
1971 {
1972         if (ec_query_wq) {
1973                 destroy_workqueue(ec_query_wq);
1974                 ec_query_wq = NULL;
1975         }
1976 }
1977
1978 int __init acpi_ec_init(void)
1979 {
1980         int result;
1981
1982         /* register workqueue for _Qxx evaluations */
1983         result = acpi_ec_query_init();
1984         if (result)
1985                 goto err_exit;
1986         /* Now register the driver for the EC */
1987         result = acpi_bus_register_driver(&acpi_ec_driver);
1988         if (result)
1989                 goto err_exit;
1990
1991 err_exit:
1992         if (result)
1993                 acpi_ec_query_exit();
1994         return result;
1995 }
1996
1997 /* EC driver currently not unloadable */
1998 #if 0
1999 static void __exit acpi_ec_exit(void)
2000 {
2001
2002         acpi_bus_unregister_driver(&acpi_ec_driver);
2003         acpi_ec_query_exit();
2004 }
2005 #endif  /* 0 */