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Linux/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 #ifdef CONFIG_PM_SLEEP
530 static bool acpi_ec_query_flushed(struct acpi_ec *ec)
531 {
532         bool flushed;
533         unsigned long flags;
534 
535         spin_lock_irqsave(&ec->lock, flags);
536         flushed = !ec->nr_pending_queries;
537         spin_unlock_irqrestore(&ec->lock, flags);
538         return flushed;
539 }
540 
541 static void __acpi_ec_flush_event(struct acpi_ec *ec)
542 {
543         /*
544          * When ec_freeze_events is true, we need to flush events in
545          * the proper position before entering the noirq stage.
546          */
547         wait_event(ec->wait, acpi_ec_query_flushed(ec));
548         if (ec_query_wq)
549                 flush_workqueue(ec_query_wq);
550 }
551 
552 static void acpi_ec_disable_event(struct acpi_ec *ec)
553 {
554         unsigned long flags;
555 
556         spin_lock_irqsave(&ec->lock, flags);
557         __acpi_ec_disable_event(ec);
558         spin_unlock_irqrestore(&ec->lock, flags);
559         __acpi_ec_flush_event(ec);
560 }
561 #endif /* CONFIG_PM_SLEEP */
562 
563 static bool acpi_ec_guard_event(struct acpi_ec *ec)
564 {
565         bool guarded = true;
566         unsigned long flags;
567 
568         spin_lock_irqsave(&ec->lock, flags);
569         /*
570          * If firmware SCI_EVT clearing timing is "event", we actually
571          * don't know when the SCI_EVT will be cleared by firmware after
572          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
573          * acceptable period.
574          *
575          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
576          * flagged, which means SCI_EVT check has just been performed.
577          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
578          * guarding should have already been performed (via
579          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
580          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
581          * ACPI_EC_COMMAND_POLL state immediately.
582          */
583         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
584             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
585             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
586             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
587                 guarded = false;
588         spin_unlock_irqrestore(&ec->lock, flags);
589         return guarded;
590 }
591 
592 static int ec_transaction_polled(struct acpi_ec *ec)
593 {
594         unsigned long flags;
595         int ret = 0;
596 
597         spin_lock_irqsave(&ec->lock, flags);
598         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
599                 ret = 1;
600         spin_unlock_irqrestore(&ec->lock, flags);
601         return ret;
602 }
603 
604 static int ec_transaction_completed(struct acpi_ec *ec)
605 {
606         unsigned long flags;
607         int ret = 0;
608 
609         spin_lock_irqsave(&ec->lock, flags);
610         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
611                 ret = 1;
612         spin_unlock_irqrestore(&ec->lock, flags);
613         return ret;
614 }
615 
616 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
617 {
618         ec->curr->flags |= flag;
619         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
620                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
621                     flag == ACPI_EC_COMMAND_POLL)
622                         acpi_ec_complete_query(ec);
623                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
624                     flag == ACPI_EC_COMMAND_COMPLETE)
625                         acpi_ec_complete_query(ec);
626                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
627                     flag == ACPI_EC_COMMAND_COMPLETE)
628                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
629         }
630 }
631 
632 static void advance_transaction(struct acpi_ec *ec)
633 {
634         struct transaction *t;
635         u8 status;
636         bool wakeup = false;
637 
638         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
639                    smp_processor_id());
640         /*
641          * By always clearing STS before handling all indications, we can
642          * ensure a hardware STS 0->1 change after this clearing can always
643          * trigger a GPE interrupt.
644          */
645         acpi_ec_clear_gpe(ec);
646         status = acpi_ec_read_status(ec);
647         t = ec->curr;
648         /*
649          * Another IRQ or a guarded polling mode advancement is detected,
650          * the next QR_EC submission is then allowed.
651          */
652         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
653                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
654                     (!ec->nr_pending_queries ||
655                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
656                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
657                         acpi_ec_complete_query(ec);
658                 }
659         }
660         if (!t)
661                 goto err;
662         if (t->flags & ACPI_EC_COMMAND_POLL) {
663                 if (t->wlen > t->wi) {
664                         if ((status & ACPI_EC_FLAG_IBF) == 0)
665                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
666                         else
667                                 goto err;
668                 } else if (t->rlen > t->ri) {
669                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
670                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
671                                 if (t->rlen == t->ri) {
672                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
673                                         if (t->command == ACPI_EC_COMMAND_QUERY)
674                                                 ec_dbg_evt("Command(%s) completed by hardware",
675                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
676                                         wakeup = true;
677                                 }
678                         } else
679                                 goto err;
680                 } else if (t->wlen == t->wi &&
681                            (status & ACPI_EC_FLAG_IBF) == 0) {
682                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
683                         wakeup = true;
684                 }
685                 goto out;
686         } else {
687                 if (EC_FLAGS_QUERY_HANDSHAKE &&
688                     !(status & ACPI_EC_FLAG_SCI) &&
689                     (t->command == ACPI_EC_COMMAND_QUERY)) {
690                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
691                         t->rdata[t->ri++] = 0x00;
692                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
693                         ec_dbg_evt("Command(%s) completed by software",
694                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
695                         wakeup = true;
696                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
697                         acpi_ec_write_cmd(ec, t->command);
698                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
699                 } else
700                         goto err;
701                 goto out;
702         }
703 err:
704         /*
705          * If SCI bit is set, then don't think it's a false IRQ
706          * otherwise will take a not handled IRQ as a false one.
707          */
708         if (!(status & ACPI_EC_FLAG_SCI)) {
709                 if (in_interrupt() && t) {
710                         if (t->irq_count < ec_storm_threshold)
711                                 ++t->irq_count;
712                         /* Allow triggering on 0 threshold */
713                         if (t->irq_count == ec_storm_threshold)
714                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
715                 }
716         }
717 out:
718         if (status & ACPI_EC_FLAG_SCI)
719                 acpi_ec_submit_query(ec);
720         if (wakeup && in_interrupt())
721                 wake_up(&ec->wait);
722 }
723 
724 static void start_transaction(struct acpi_ec *ec)
725 {
726         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
727         ec->curr->flags = 0;
728 }
729 
730 static int ec_guard(struct acpi_ec *ec)
731 {
732         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
733         unsigned long timeout = ec->timestamp + guard;
734 
735         /* Ensure guarding period before polling EC status */
736         do {
737                 if (ec_busy_polling) {
738                         /* Perform busy polling */
739                         if (ec_transaction_completed(ec))
740                                 return 0;
741                         udelay(jiffies_to_usecs(guard));
742                 } else {
743                         /*
744                          * Perform wait polling
745                          * 1. Wait the transaction to be completed by the
746                          *    GPE handler after the transaction enters
747                          *    ACPI_EC_COMMAND_POLL state.
748                          * 2. A special guarding logic is also required
749                          *    for event clearing mode "event" before the
750                          *    transaction enters ACPI_EC_COMMAND_POLL
751                          *    state.
752                          */
753                         if (!ec_transaction_polled(ec) &&
754                             !acpi_ec_guard_event(ec))
755                                 break;
756                         if (wait_event_timeout(ec->wait,
757                                                ec_transaction_completed(ec),
758                                                guard))
759                                 return 0;
760                 }
761         } while (time_before(jiffies, timeout));
762         return -ETIME;
763 }
764 
765 static int ec_poll(struct acpi_ec *ec)
766 {
767         unsigned long flags;
768         int repeat = 5; /* number of command restarts */
769 
770         while (repeat--) {
771                 unsigned long delay = jiffies +
772                         msecs_to_jiffies(ec_delay);
773                 do {
774                         if (!ec_guard(ec))
775                                 return 0;
776                         spin_lock_irqsave(&ec->lock, flags);
777                         advance_transaction(ec);
778                         spin_unlock_irqrestore(&ec->lock, flags);
779                 } while (time_before(jiffies, delay));
780                 pr_debug("controller reset, restart transaction\n");
781                 spin_lock_irqsave(&ec->lock, flags);
782                 start_transaction(ec);
783                 spin_unlock_irqrestore(&ec->lock, flags);
784         }
785         return -ETIME;
786 }
787 
788 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
789                                         struct transaction *t)
790 {
791         unsigned long tmp;
792         int ret = 0;
793 
794         /* start transaction */
795         spin_lock_irqsave(&ec->lock, tmp);
796         /* Enable GPE for command processing (IBF=0/OBF=1) */
797         if (!acpi_ec_submit_flushable_request(ec)) {
798                 ret = -EINVAL;
799                 goto unlock;
800         }
801         ec_dbg_ref(ec, "Increase command");
802         /* following two actions should be kept atomic */
803         ec->curr = t;
804         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
805         start_transaction(ec);
806         spin_unlock_irqrestore(&ec->lock, tmp);
807 
808         ret = ec_poll(ec);
809 
810         spin_lock_irqsave(&ec->lock, tmp);
811         if (t->irq_count == ec_storm_threshold)
812                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
813         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
814         ec->curr = NULL;
815         /* Disable GPE for command processing (IBF=0/OBF=1) */
816         acpi_ec_complete_request(ec);
817         ec_dbg_ref(ec, "Decrease command");
818 unlock:
819         spin_unlock_irqrestore(&ec->lock, tmp);
820         return ret;
821 }
822 
823 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
824 {
825         int status;
826         u32 glk;
827 
828         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
829                 return -EINVAL;
830         if (t->rdata)
831                 memset(t->rdata, 0, t->rlen);
832 
833         mutex_lock(&ec->mutex);
834         if (ec->global_lock) {
835                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
836                 if (ACPI_FAILURE(status)) {
837                         status = -ENODEV;
838                         goto unlock;
839                 }
840         }
841 
842         status = acpi_ec_transaction_unlocked(ec, t);
843 
844         if (ec->global_lock)
845                 acpi_release_global_lock(glk);
846 unlock:
847         mutex_unlock(&ec->mutex);
848         return status;
849 }
850 
851 static int acpi_ec_burst_enable(struct acpi_ec *ec)
852 {
853         u8 d;
854         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
855                                 .wdata = NULL, .rdata = &d,
856                                 .wlen = 0, .rlen = 1};
857 
858         return acpi_ec_transaction(ec, &t);
859 }
860 
861 static int acpi_ec_burst_disable(struct acpi_ec *ec)
862 {
863         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
864                                 .wdata = NULL, .rdata = NULL,
865                                 .wlen = 0, .rlen = 0};
866 
867         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
868                                 acpi_ec_transaction(ec, &t) : 0;
869 }
870 
871 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
872 {
873         int result;
874         u8 d;
875         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
876                                 .wdata = &address, .rdata = &d,
877                                 .wlen = 1, .rlen = 1};
878 
879         result = acpi_ec_transaction(ec, &t);
880         *data = d;
881         return result;
882 }
883 
884 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
885 {
886         u8 wdata[2] = { address, data };
887         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
888                                 .wdata = wdata, .rdata = NULL,
889                                 .wlen = 2, .rlen = 0};
890 
891         return acpi_ec_transaction(ec, &t);
892 }
893 
894 int ec_read(u8 addr, u8 *val)
895 {
896         int err;
897         u8 temp_data;
898 
899         if (!first_ec)
900                 return -ENODEV;
901 
902         err = acpi_ec_read(first_ec, addr, &temp_data);
903 
904         if (!err) {
905                 *val = temp_data;
906                 return 0;
907         }
908         return err;
909 }
910 EXPORT_SYMBOL(ec_read);
911 
912 int ec_write(u8 addr, u8 val)
913 {
914         int err;
915 
916         if (!first_ec)
917                 return -ENODEV;
918 
919         err = acpi_ec_write(first_ec, addr, val);
920 
921         return err;
922 }
923 EXPORT_SYMBOL(ec_write);
924 
925 int ec_transaction(u8 command,
926                    const u8 *wdata, unsigned wdata_len,
927                    u8 *rdata, unsigned rdata_len)
928 {
929         struct transaction t = {.command = command,
930                                 .wdata = wdata, .rdata = rdata,
931                                 .wlen = wdata_len, .rlen = rdata_len};
932 
933         if (!first_ec)
934                 return -ENODEV;
935 
936         return acpi_ec_transaction(first_ec, &t);
937 }
938 EXPORT_SYMBOL(ec_transaction);
939 
940 /* Get the handle to the EC device */
941 acpi_handle ec_get_handle(void)
942 {
943         if (!first_ec)
944                 return NULL;
945         return first_ec->handle;
946 }
947 EXPORT_SYMBOL(ec_get_handle);
948 
949 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
950 {
951         unsigned long flags;
952 
953         spin_lock_irqsave(&ec->lock, flags);
954         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
955                 ec_dbg_drv("Starting EC");
956                 /* Enable GPE for event processing (SCI_EVT=1) */
957                 if (!resuming) {
958                         acpi_ec_submit_request(ec);
959                         ec_dbg_ref(ec, "Increase driver");
960                 }
961                 ec_log_drv("EC started");
962         }
963         spin_unlock_irqrestore(&ec->lock, flags);
964 }
965 
966 static bool acpi_ec_stopped(struct acpi_ec *ec)
967 {
968         unsigned long flags;
969         bool flushed;
970 
971         spin_lock_irqsave(&ec->lock, flags);
972         flushed = acpi_ec_flushed(ec);
973         spin_unlock_irqrestore(&ec->lock, flags);
974         return flushed;
975 }
976 
977 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
978 {
979         unsigned long flags;
980 
981         spin_lock_irqsave(&ec->lock, flags);
982         if (acpi_ec_started(ec)) {
983                 ec_dbg_drv("Stopping EC");
984                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
985                 spin_unlock_irqrestore(&ec->lock, flags);
986                 wait_event(ec->wait, acpi_ec_stopped(ec));
987                 spin_lock_irqsave(&ec->lock, flags);
988                 /* Disable GPE for event processing (SCI_EVT=1) */
989                 if (!suspending) {
990                         acpi_ec_complete_request(ec);
991                         ec_dbg_ref(ec, "Decrease driver");
992                 } else if (!ec_freeze_events)
993                         __acpi_ec_disable_event(ec);
994                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
995                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
996                 ec_log_drv("EC stopped");
997         }
998         spin_unlock_irqrestore(&ec->lock, flags);
999 }
1000 
1001 void acpi_ec_block_transactions(void)
1002 {
1003         struct acpi_ec *ec = first_ec;
1004 
1005         if (!ec)
1006                 return;
1007 
1008         mutex_lock(&ec->mutex);
1009         /* Prevent transactions from being carried out */
1010         acpi_ec_stop(ec, true);
1011         mutex_unlock(&ec->mutex);
1012 }
1013 
1014 void acpi_ec_unblock_transactions(void)
1015 {
1016         /*
1017          * Allow transactions to happen again (this function is called from
1018          * atomic context during wakeup, so we don't need to acquire the mutex).
1019          */
1020         if (first_ec)
1021                 acpi_ec_start(first_ec, true);
1022 }
1023 
1024 /* --------------------------------------------------------------------------
1025                                 Event Management
1026    -------------------------------------------------------------------------- */
1027 static struct acpi_ec_query_handler *
1028 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
1029 {
1030         if (handler)
1031                 kref_get(&handler->kref);
1032         return handler;
1033 }
1034 
1035 static struct acpi_ec_query_handler *
1036 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1037 {
1038         struct acpi_ec_query_handler *handler;
1039         bool found = false;
1040 
1041         mutex_lock(&ec->mutex);
1042         list_for_each_entry(handler, &ec->list, node) {
1043                 if (value == handler->query_bit) {
1044                         found = true;
1045                         break;
1046                 }
1047         }
1048         mutex_unlock(&ec->mutex);
1049         return found ? acpi_ec_get_query_handler(handler) : NULL;
1050 }
1051 
1052 static void acpi_ec_query_handler_release(struct kref *kref)
1053 {
1054         struct acpi_ec_query_handler *handler =
1055                 container_of(kref, struct acpi_ec_query_handler, kref);
1056 
1057         kfree(handler);
1058 }
1059 
1060 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1061 {
1062         kref_put(&handler->kref, acpi_ec_query_handler_release);
1063 }
1064 
1065 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1066                               acpi_handle handle, acpi_ec_query_func func,
1067                               void *data)
1068 {
1069         struct acpi_ec_query_handler *handler =
1070             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1071 
1072         if (!handler)
1073                 return -ENOMEM;
1074 
1075         handler->query_bit = query_bit;
1076         handler->handle = handle;
1077         handler->func = func;
1078         handler->data = data;
1079         mutex_lock(&ec->mutex);
1080         kref_init(&handler->kref);
1081         list_add(&handler->node, &ec->list);
1082         mutex_unlock(&ec->mutex);
1083         return 0;
1084 }
1085 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1086 
1087 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1088                                           bool remove_all, u8 query_bit)
1089 {
1090         struct acpi_ec_query_handler *handler, *tmp;
1091         LIST_HEAD(free_list);
1092 
1093         mutex_lock(&ec->mutex);
1094         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1095                 if (remove_all || query_bit == handler->query_bit) {
1096                         list_del_init(&handler->node);
1097                         list_add(&handler->node, &free_list);
1098                 }
1099         }
1100         mutex_unlock(&ec->mutex);
1101         list_for_each_entry_safe(handler, tmp, &free_list, node)
1102                 acpi_ec_put_query_handler(handler);
1103 }
1104 
1105 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1106 {
1107         acpi_ec_remove_query_handlers(ec, false, query_bit);
1108 }
1109 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1110 
1111 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1112 {
1113         struct acpi_ec_query *q;
1114         struct transaction *t;
1115 
1116         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1117         if (!q)
1118                 return NULL;
1119         INIT_WORK(&q->work, acpi_ec_event_processor);
1120         t = &q->transaction;
1121         t->command = ACPI_EC_COMMAND_QUERY;
1122         t->rdata = pval;
1123         t->rlen = 1;
1124         return q;
1125 }
1126 
1127 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1128 {
1129         if (q) {
1130                 if (q->handler)
1131                         acpi_ec_put_query_handler(q->handler);
1132                 kfree(q);
1133         }
1134 }
1135 
1136 static void acpi_ec_event_processor(struct work_struct *work)
1137 {
1138         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1139         struct acpi_ec_query_handler *handler = q->handler;
1140 
1141         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1142         if (handler->func)
1143                 handler->func(handler->data);
1144         else if (handler->handle)
1145                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1146         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1147         acpi_ec_delete_query(q);
1148 }
1149 
1150 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1151 {
1152         u8 value = 0;
1153         int result;
1154         struct acpi_ec_query *q;
1155 
1156         q = acpi_ec_create_query(&value);
1157         if (!q)
1158                 return -ENOMEM;
1159 
1160         /*
1161          * Query the EC to find out which _Qxx method we need to evaluate.
1162          * Note that successful completion of the query causes the ACPI_EC_SCI
1163          * bit to be cleared (and thus clearing the interrupt source).
1164          */
1165         result = acpi_ec_transaction(ec, &q->transaction);
1166         if (!value)
1167                 result = -ENODATA;
1168         if (result)
1169                 goto err_exit;
1170 
1171         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1172         if (!q->handler) {
1173                 result = -ENODATA;
1174                 goto err_exit;
1175         }
1176 
1177         /*
1178          * It is reported that _Qxx are evaluated in a parallel way on
1179          * Windows:
1180          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1181          *
1182          * Put this log entry before schedule_work() in order to make
1183          * it appearing before any other log entries occurred during the
1184          * work queue execution.
1185          */
1186         ec_dbg_evt("Query(0x%02x) scheduled", value);
1187         if (!queue_work(ec_query_wq, &q->work)) {
1188                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1189                 result = -EBUSY;
1190         }
1191 
1192 err_exit:
1193         if (result)
1194                 acpi_ec_delete_query(q);
1195         if (data)
1196                 *data = value;
1197         return result;
1198 }
1199 
1200 static void acpi_ec_check_event(struct acpi_ec *ec)
1201 {
1202         unsigned long flags;
1203 
1204         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1205                 if (ec_guard(ec)) {
1206                         spin_lock_irqsave(&ec->lock, flags);
1207                         /*
1208                          * Take care of the SCI_EVT unless no one else is
1209                          * taking care of it.
1210                          */
1211                         if (!ec->curr)
1212                                 advance_transaction(ec);
1213                         spin_unlock_irqrestore(&ec->lock, flags);
1214                 }
1215         }
1216 }
1217 
1218 static void acpi_ec_event_handler(struct work_struct *work)
1219 {
1220         unsigned long flags;
1221         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1222 
1223         ec_dbg_evt("Event started");
1224 
1225         spin_lock_irqsave(&ec->lock, flags);
1226         while (ec->nr_pending_queries) {
1227                 spin_unlock_irqrestore(&ec->lock, flags);
1228                 (void)acpi_ec_query(ec, NULL);
1229                 spin_lock_irqsave(&ec->lock, flags);
1230                 ec->nr_pending_queries--;
1231                 /*
1232                  * Before exit, make sure that this work item can be
1233                  * scheduled again. There might be QR_EC failures, leaving
1234                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1235                  * item from being scheduled again.
1236                  */
1237                 if (!ec->nr_pending_queries) {
1238                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1239                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1240                                 acpi_ec_complete_query(ec);
1241                 }
1242         }
1243         spin_unlock_irqrestore(&ec->lock, flags);
1244 
1245         ec_dbg_evt("Event stopped");
1246 
1247         acpi_ec_check_event(ec);
1248 }
1249 
1250 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1251         u32 gpe_number, void *data)
1252 {
1253         unsigned long flags;
1254         struct acpi_ec *ec = data;
1255 
1256         spin_lock_irqsave(&ec->lock, flags);
1257         advance_transaction(ec);
1258         spin_unlock_irqrestore(&ec->lock, flags);
1259         return ACPI_INTERRUPT_HANDLED;
1260 }
1261 
1262 /* --------------------------------------------------------------------------
1263  *                           Address Space Management
1264  * -------------------------------------------------------------------------- */
1265 
1266 static acpi_status
1267 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1268                       u32 bits, u64 *value64,
1269                       void *handler_context, void *region_context)
1270 {
1271         struct acpi_ec *ec = handler_context;
1272         int result = 0, i, bytes = bits / 8;
1273         u8 *value = (u8 *)value64;
1274 
1275         if ((address > 0xFF) || !value || !handler_context)
1276                 return AE_BAD_PARAMETER;
1277 
1278         if (function != ACPI_READ && function != ACPI_WRITE)
1279                 return AE_BAD_PARAMETER;
1280 
1281         if (ec_busy_polling || bits > 8)
1282                 acpi_ec_burst_enable(ec);
1283 
1284         for (i = 0; i < bytes; ++i, ++address, ++value)
1285                 result = (function == ACPI_READ) ?
1286                         acpi_ec_read(ec, address, value) :
1287                         acpi_ec_write(ec, address, *value);
1288 
1289         if (ec_busy_polling || bits > 8)
1290                 acpi_ec_burst_disable(ec);
1291 
1292         switch (result) {
1293         case -EINVAL:
1294                 return AE_BAD_PARAMETER;
1295         case -ENODEV:
1296                 return AE_NOT_FOUND;
1297         case -ETIME:
1298                 return AE_TIME;
1299         default:
1300                 return AE_OK;
1301         }
1302 }
1303 
1304 /* --------------------------------------------------------------------------
1305  *                             Driver Interface
1306  * -------------------------------------------------------------------------- */
1307 
1308 static acpi_status
1309 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1310 
1311 static void acpi_ec_free(struct acpi_ec *ec)
1312 {
1313         if (first_ec == ec)
1314                 first_ec = NULL;
1315         if (boot_ec == ec)
1316                 boot_ec = NULL;
1317         kfree(ec);
1318 }
1319 
1320 static struct acpi_ec *acpi_ec_alloc(void)
1321 {
1322         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1323 
1324         if (!ec)
1325                 return NULL;
1326         mutex_init(&ec->mutex);
1327         init_waitqueue_head(&ec->wait);
1328         INIT_LIST_HEAD(&ec->list);
1329         spin_lock_init(&ec->lock);
1330         INIT_WORK(&ec->work, acpi_ec_event_handler);
1331         ec->timestamp = jiffies;
1332         return ec;
1333 }
1334 
1335 static acpi_status
1336 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1337                                void *context, void **return_value)
1338 {
1339         char node_name[5];
1340         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1341         struct acpi_ec *ec = context;
1342         int value = 0;
1343         acpi_status status;
1344 
1345         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1346 
1347         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1348                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1349         return AE_OK;
1350 }
1351 
1352 static acpi_status
1353 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1354 {
1355         acpi_status status;
1356         unsigned long long tmp = 0;
1357         struct acpi_ec *ec = context;
1358 
1359         /* clear addr values, ec_parse_io_ports depend on it */
1360         ec->command_addr = ec->data_addr = 0;
1361 
1362         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1363                                      ec_parse_io_ports, ec);
1364         if (ACPI_FAILURE(status))
1365                 return status;
1366 
1367         /* Get GPE bit assignment (EC events). */
1368         /* TODO: Add support for _GPE returning a package */
1369         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1370         if (ACPI_FAILURE(status))
1371                 return status;
1372         ec->gpe = tmp;
1373         /* Use the global lock for all EC transactions? */
1374         tmp = 0;
1375         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1376         ec->global_lock = tmp;
1377         ec->handle = handle;
1378         return AE_CTRL_TERMINATE;
1379 }
1380 
1381 /*
1382  * Note: This function returns an error code only when the address space
1383  *       handler is not installed, which means "not able to handle
1384  *       transactions".
1385  */
1386 static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1387 {
1388         acpi_status status;
1389 
1390         acpi_ec_start(ec, false);
1391 
1392         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1393                 status = acpi_install_address_space_handler(ec->handle,
1394                                                             ACPI_ADR_SPACE_EC,
1395                                                             &acpi_ec_space_handler,
1396                                                             NULL, ec);
1397                 if (ACPI_FAILURE(status)) {
1398                         if (status == AE_NOT_FOUND) {
1399                                 /*
1400                                  * Maybe OS fails in evaluating the _REG
1401                                  * object. The AE_NOT_FOUND error will be
1402                                  * ignored and OS * continue to initialize
1403                                  * EC.
1404                                  */
1405                                 pr_err("Fail in evaluating the _REG object"
1406                                         " of EC device. Broken bios is suspected.\n");
1407                         } else {
1408                                 acpi_ec_stop(ec, false);
1409                                 return -ENODEV;
1410                         }
1411                 }
1412                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1413         }
1414 
1415         if (!handle_events)
1416                 return 0;
1417 
1418         if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1419                 /* Find and register all query methods */
1420                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1421                                     acpi_ec_register_query_methods,
1422                                     NULL, ec, NULL);
1423                 set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1424         }
1425         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1426                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1427                                           ACPI_GPE_EDGE_TRIGGERED,
1428                                           &acpi_ec_gpe_handler, ec);
1429                 /* This is not fatal as we can poll EC events */
1430                 if (ACPI_SUCCESS(status)) {
1431                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1432                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1433                             ec->reference_count >= 1)
1434                                 acpi_ec_enable_gpe(ec, true);
1435 
1436                         /* EC is fully operational, allow queries */
1437                         acpi_ec_enable_event(ec);
1438                 }
1439         }
1440 
1441         return 0;
1442 }
1443 
1444 static void ec_remove_handlers(struct acpi_ec *ec)
1445 {
1446         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1447                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1448                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1449                         pr_err("failed to remove space handler\n");
1450                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1451         }
1452 
1453         /*
1454          * Stops handling the EC transactions after removing the operation
1455          * region handler. This is required because _REG(DISCONNECT)
1456          * invoked during the removal can result in new EC transactions.
1457          *
1458          * Flushes the EC requests and thus disables the GPE before
1459          * removing the GPE handler. This is required by the current ACPICA
1460          * GPE core. ACPICA GPE core will automatically disable a GPE when
1461          * it is indicated but there is no way to handle it. So the drivers
1462          * must disable the GPEs prior to removing the GPE handlers.
1463          */
1464         acpi_ec_stop(ec, false);
1465 
1466         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1467                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1468                                         &acpi_ec_gpe_handler)))
1469                         pr_err("failed to remove gpe handler\n");
1470                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1471         }
1472         if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1473                 acpi_ec_remove_query_handlers(ec, true, 0);
1474                 clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1475         }
1476 }
1477 
1478 static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1479 {
1480         int ret;
1481 
1482         ret = ec_install_handlers(ec, handle_events);
1483         if (ret)
1484                 return ret;
1485 
1486         /* First EC capable of handling transactions */
1487         if (!first_ec) {
1488                 first_ec = ec;
1489                 acpi_handle_info(first_ec->handle, "Used as first EC\n");
1490         }
1491 
1492         acpi_handle_info(ec->handle,
1493                          "GPE=0x%lx, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1494                          ec->gpe, ec->command_addr, ec->data_addr);
1495         return ret;
1496 }
1497 
1498 static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
1499                                bool handle_events, bool is_ecdt)
1500 {
1501         int ret;
1502 
1503         /*
1504          * Changing the ACPI handle results in a re-configuration of the
1505          * boot EC. And if it happens after the namespace initialization,
1506          * it causes _REG evaluations.
1507          */
1508         if (boot_ec && boot_ec->handle != handle)
1509                 ec_remove_handlers(boot_ec);
1510 
1511         /* Unset old boot EC */
1512         if (boot_ec != ec)
1513                 acpi_ec_free(boot_ec);
1514 
1515         /*
1516          * ECDT device creation is split into acpi_ec_ecdt_probe() and
1517          * acpi_ec_ecdt_start(). This function takes care of completing the
1518          * ECDT parsing logic as the handle update should be performed
1519          * between the installation/uninstallation of the handlers.
1520          */
1521         if (ec->handle != handle)
1522                 ec->handle = handle;
1523 
1524         ret = acpi_ec_setup(ec, handle_events);
1525         if (ret)
1526                 return ret;
1527 
1528         /* Set new boot EC */
1529         if (!boot_ec) {
1530                 boot_ec = ec;
1531                 boot_ec_is_ecdt = is_ecdt;
1532         }
1533 
1534         acpi_handle_info(boot_ec->handle,
1535                          "Used as boot %s EC to handle transactions%s\n",
1536                          is_ecdt ? "ECDT" : "DSDT",
1537                          handle_events ? " and events" : "");
1538         return ret;
1539 }
1540 
1541 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1542 {
1543         struct acpi_table_ecdt *ecdt_ptr;
1544         acpi_status status;
1545         acpi_handle handle;
1546 
1547         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1548                                 (struct acpi_table_header **)&ecdt_ptr);
1549         if (ACPI_FAILURE(status))
1550                 return false;
1551 
1552         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1553         if (ACPI_FAILURE(status))
1554                 return false;
1555 
1556         *phandle = handle;
1557         return true;
1558 }
1559 
1560 static bool acpi_is_boot_ec(struct acpi_ec *ec)
1561 {
1562         if (!boot_ec)
1563                 return false;
1564         if (ec->handle == boot_ec->handle &&
1565             ec->gpe == boot_ec->gpe &&
1566             ec->command_addr == boot_ec->command_addr &&
1567             ec->data_addr == boot_ec->data_addr)
1568                 return true;
1569         return false;
1570 }
1571 
1572 static int acpi_ec_add(struct acpi_device *device)
1573 {
1574         struct acpi_ec *ec = NULL;
1575         int ret;
1576 
1577         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1578         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1579 
1580         ec = acpi_ec_alloc();
1581         if (!ec)
1582                 return -ENOMEM;
1583         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1584                 AE_CTRL_TERMINATE) {
1585                         ret = -EINVAL;
1586                         goto err_alloc;
1587         }
1588 
1589         if (acpi_is_boot_ec(ec)) {
1590                 boot_ec_is_ecdt = false;
1591                 acpi_handle_debug(ec->handle, "duplicated.\n");
1592                 acpi_ec_free(ec);
1593                 ec = boot_ec;
1594                 ret = acpi_config_boot_ec(ec, ec->handle, true, false);
1595         } else
1596                 ret = acpi_ec_setup(ec, true);
1597         if (ret)
1598                 goto err_query;
1599 
1600         device->driver_data = ec;
1601 
1602         ret = !!request_region(ec->data_addr, 1, "EC data");
1603         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1604         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1605         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1606 
1607         /* Reprobe devices depending on the EC */
1608         acpi_walk_dep_device_list(ec->handle);
1609         acpi_handle_debug(ec->handle, "enumerated.\n");
1610         return 0;
1611 
1612 err_query:
1613         if (ec != boot_ec)
1614                 acpi_ec_remove_query_handlers(ec, true, 0);
1615 err_alloc:
1616         if (ec != boot_ec)
1617                 acpi_ec_free(ec);
1618         return ret;
1619 }
1620 
1621 static int acpi_ec_remove(struct acpi_device *device)
1622 {
1623         struct acpi_ec *ec;
1624 
1625         if (!device)
1626                 return -EINVAL;
1627 
1628         ec = acpi_driver_data(device);
1629         release_region(ec->data_addr, 1);
1630         release_region(ec->command_addr, 1);
1631         device->driver_data = NULL;
1632         if (ec != boot_ec) {
1633                 ec_remove_handlers(ec);
1634                 acpi_ec_free(ec);
1635         }
1636         return 0;
1637 }
1638 
1639 static acpi_status
1640 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1641 {
1642         struct acpi_ec *ec = context;
1643 
1644         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1645                 return AE_OK;
1646 
1647         /*
1648          * The first address region returned is the data port, and
1649          * the second address region returned is the status/command
1650          * port.
1651          */
1652         if (ec->data_addr == 0)
1653                 ec->data_addr = resource->data.io.minimum;
1654         else if (ec->command_addr == 0)
1655                 ec->command_addr = resource->data.io.minimum;
1656         else
1657                 return AE_CTRL_TERMINATE;
1658 
1659         return AE_OK;
1660 }
1661 
1662 static const struct acpi_device_id ec_device_ids[] = {
1663         {"PNP0C09", 0},
1664         {"", 0},
1665 };
1666 
1667 int __init acpi_ec_dsdt_probe(void)
1668 {
1669         acpi_status status;
1670         struct acpi_ec *ec;
1671         int ret;
1672 
1673         ec = acpi_ec_alloc();
1674         if (!ec)
1675                 return -ENOMEM;
1676         /*
1677          * At this point, the namespace is initialized, so start to find
1678          * the namespace objects.
1679          */
1680         status = acpi_get_devices(ec_device_ids[0].id,
1681                                   ec_parse_device, ec, NULL);
1682         if (ACPI_FAILURE(status) || !ec->handle) {
1683                 ret = -ENODEV;
1684                 goto error;
1685         }
1686         /*
1687          * When the DSDT EC is available, always re-configure boot EC to
1688          * have _REG evaluated. _REG can only be evaluated after the
1689          * namespace initialization.
1690          * At this point, the GPE is not fully initialized, so do not to
1691          * handle the events.
1692          */
1693         ret = acpi_config_boot_ec(ec, ec->handle, false, false);
1694 error:
1695         if (ret)
1696                 acpi_ec_free(ec);
1697         return ret;
1698 }
1699 
1700 /*
1701  * If the DSDT EC is not functioning, we still need to prepare a fully
1702  * functioning ECDT EC first in order to handle the events.
1703  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1704  */
1705 int __init acpi_ec_ecdt_start(void)
1706 {
1707         acpi_handle handle;
1708 
1709         if (!boot_ec)
1710                 return -ENODEV;
1711         /*
1712          * The DSDT EC should have already been started in
1713          * acpi_ec_add().
1714          */
1715         if (!boot_ec_is_ecdt)
1716                 return -ENODEV;
1717 
1718         /*
1719          * At this point, the namespace and the GPE is initialized, so
1720          * start to find the namespace objects and handle the events.
1721          */
1722         if (!acpi_ec_ecdt_get_handle(&handle))
1723                 return -ENODEV;
1724         return acpi_config_boot_ec(boot_ec, handle, true, true);
1725 }
1726 
1727 #if 0
1728 /*
1729  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1730  * set, for which case, we complete the QR_EC without issuing it to the
1731  * firmware.
1732  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1733  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1734  */
1735 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1736 {
1737         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1738         EC_FLAGS_QUERY_HANDSHAKE = 1;
1739         return 0;
1740 }
1741 #endif
1742 
1743 /*
1744  * On some hardware it is necessary to clear events accumulated by the EC during
1745  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1746  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1747  *
1748  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1749  *
1750  * Ideally, the EC should also be instructed NOT to accumulate events during
1751  * sleep (which Windows seems to do somehow), but the interface to control this
1752  * behaviour is not known at this time.
1753  *
1754  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1755  * however it is very likely that other Samsung models are affected.
1756  *
1757  * On systems which don't accumulate _Q events during sleep, this extra check
1758  * should be harmless.
1759  */
1760 static int ec_clear_on_resume(const struct dmi_system_id *id)
1761 {
1762         pr_debug("Detected system needing EC poll on resume.\n");
1763         EC_FLAGS_CLEAR_ON_RESUME = 1;
1764         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1765         return 0;
1766 }
1767 
1768 /*
1769  * Some ECDTs contain wrong register addresses.
1770  * MSI MS-171F
1771  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1772  */
1773 static int ec_correct_ecdt(const struct dmi_system_id *id)
1774 {
1775         pr_debug("Detected system needing ECDT address correction.\n");
1776         EC_FLAGS_CORRECT_ECDT = 1;
1777         return 0;
1778 }
1779 
1780 static struct dmi_system_id ec_dmi_table[] __initdata = {
1781         {
1782         ec_correct_ecdt, "MSI MS-171F", {
1783         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1784         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1785         {
1786         ec_clear_on_resume, "Samsung hardware", {
1787         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1788         {},
1789 };
1790 
1791 int __init acpi_ec_ecdt_probe(void)
1792 {
1793         int ret;
1794         acpi_status status;
1795         struct acpi_table_ecdt *ecdt_ptr;
1796         struct acpi_ec *ec;
1797 
1798         ec = acpi_ec_alloc();
1799         if (!ec)
1800                 return -ENOMEM;
1801         /*
1802          * Generate a boot ec context
1803          */
1804         dmi_check_system(ec_dmi_table);
1805         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1806                                 (struct acpi_table_header **)&ecdt_ptr);
1807         if (ACPI_FAILURE(status)) {
1808                 ret = -ENODEV;
1809                 goto error;
1810         }
1811 
1812         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1813                 /*
1814                  * Asus X50GL:
1815                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1816                  */
1817                 ret = -ENODEV;
1818                 goto error;
1819         }
1820 
1821         if (EC_FLAGS_CORRECT_ECDT) {
1822                 ec->command_addr = ecdt_ptr->data.address;
1823                 ec->data_addr = ecdt_ptr->control.address;
1824         } else {
1825                 ec->command_addr = ecdt_ptr->control.address;
1826                 ec->data_addr = ecdt_ptr->data.address;
1827         }
1828         ec->gpe = ecdt_ptr->gpe;
1829 
1830         /*
1831          * At this point, the namespace is not initialized, so do not find
1832          * the namespace objects, or handle the events.
1833          */
1834         ret = acpi_config_boot_ec(ec, ACPI_ROOT_OBJECT, false, true);
1835 error:
1836         if (ret)
1837                 acpi_ec_free(ec);
1838         return ret;
1839 }
1840 
1841 #ifdef CONFIG_PM_SLEEP
1842 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1843 {
1844         unsigned long flags;
1845 
1846         if (ec == first_ec) {
1847                 spin_lock_irqsave(&ec->lock, flags);
1848                 ec->saved_busy_polling = ec_busy_polling;
1849                 ec->saved_polling_guard = ec_polling_guard;
1850                 ec_busy_polling = true;
1851                 ec_polling_guard = 0;
1852                 ec_log_drv("interrupt blocked");
1853                 spin_unlock_irqrestore(&ec->lock, flags);
1854         }
1855 }
1856 
1857 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1858 {
1859         unsigned long flags;
1860 
1861         if (ec == first_ec) {
1862                 spin_lock_irqsave(&ec->lock, flags);
1863                 ec_busy_polling = ec->saved_busy_polling;
1864                 ec_polling_guard = ec->saved_polling_guard;
1865                 ec_log_drv("interrupt unblocked");
1866                 spin_unlock_irqrestore(&ec->lock, flags);
1867         }
1868 }
1869 
1870 static int acpi_ec_suspend_noirq(struct device *dev)
1871 {
1872         struct acpi_ec *ec =
1873                 acpi_driver_data(to_acpi_device(dev));
1874 
1875         acpi_ec_enter_noirq(ec);
1876         return 0;
1877 }
1878 
1879 static int acpi_ec_resume_noirq(struct device *dev)
1880 {
1881         struct acpi_ec *ec =
1882                 acpi_driver_data(to_acpi_device(dev));
1883 
1884         acpi_ec_leave_noirq(ec);
1885         return 0;
1886 }
1887 
1888 static int acpi_ec_suspend(struct device *dev)
1889 {
1890         struct acpi_ec *ec =
1891                 acpi_driver_data(to_acpi_device(dev));
1892 
1893         if (ec_freeze_events)
1894                 acpi_ec_disable_event(ec);
1895         return 0;
1896 }
1897 
1898 static int acpi_ec_resume(struct device *dev)
1899 {
1900         struct acpi_ec *ec =
1901                 acpi_driver_data(to_acpi_device(dev));
1902 
1903         acpi_ec_enable_event(ec);
1904         return 0;
1905 }
1906 #endif
1907 
1908 static const struct dev_pm_ops acpi_ec_pm = {
1909         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
1910         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1911 };
1912 
1913 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1914 {
1915         int result = 0;
1916 
1917         if (!strncmp(val, "status", sizeof("status") - 1)) {
1918                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1919                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1920         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1921                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1922                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1923         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1924                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1925                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1926         } else
1927                 result = -EINVAL;
1928         return result;
1929 }
1930 
1931 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1932 {
1933         switch (ec_event_clearing) {
1934         case ACPI_EC_EVT_TIMING_STATUS:
1935                 return sprintf(buffer, "status");
1936         case ACPI_EC_EVT_TIMING_QUERY:
1937                 return sprintf(buffer, "query");
1938         case ACPI_EC_EVT_TIMING_EVENT:
1939                 return sprintf(buffer, "event");
1940         default:
1941                 return sprintf(buffer, "invalid");
1942         }
1943         return 0;
1944 }
1945 
1946 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1947                   NULL, 0644);
1948 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1949 
1950 static struct acpi_driver acpi_ec_driver = {
1951         .name = "ec",
1952         .class = ACPI_EC_CLASS,
1953         .ids = ec_device_ids,
1954         .ops = {
1955                 .add = acpi_ec_add,
1956                 .remove = acpi_ec_remove,
1957                 },
1958         .drv.pm = &acpi_ec_pm,
1959 };
1960 
1961 static inline int acpi_ec_query_init(void)
1962 {
1963         if (!ec_query_wq) {
1964                 ec_query_wq = alloc_workqueue("kec_query", 0,
1965                                               ec_max_queries);
1966                 if (!ec_query_wq)
1967                         return -ENODEV;
1968         }
1969         return 0;
1970 }
1971 
1972 static inline void acpi_ec_query_exit(void)
1973 {
1974         if (ec_query_wq) {
1975                 destroy_workqueue(ec_query_wq);
1976                 ec_query_wq = NULL;
1977         }
1978 }
1979 
1980 int __init acpi_ec_init(void)
1981 {
1982         int result;
1983 
1984         /* register workqueue for _Qxx evaluations */
1985         result = acpi_ec_query_init();
1986         if (result)
1987                 goto err_exit;
1988         /* Now register the driver for the EC */
1989         result = acpi_bus_register_driver(&acpi_ec_driver);
1990         if (result)
1991                 goto err_exit;
1992 
1993 err_exit:
1994         if (result)
1995                 acpi_ec_query_exit();
1996         return result;
1997 }
1998 
1999 /* EC driver currently not unloadable */
2000 #if 0
2001 static void __exit acpi_ec_exit(void)
2002 {
2003 
2004         acpi_bus_unregister_driver(&acpi_ec_driver);
2005         acpi_ec_query_exit();
2006 }
2007 #endif  /* 0 */
2008 

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