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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_PENDING,         /* Query is pending */
108         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
109         EC_FLAGS_GPE_HANDLER_INSTALLED, /* GPE handler installed */
110         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
111         EC_FLAGS_STARTED,               /* Driver is started */
112         EC_FLAGS_STOPPED,               /* Driver is stopped */
113         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
114                                          * current command processing */
115 };
116 
117 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
118 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
119 
120 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
121 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
122 module_param(ec_delay, uint, 0644);
123 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
124 
125 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
126 module_param(ec_max_queries, uint, 0644);
127 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
128 
129 static bool ec_busy_polling __read_mostly;
130 module_param(ec_busy_polling, bool, 0644);
131 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
132 
133 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
134 module_param(ec_polling_guard, uint, 0644);
135 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
136 
137 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
138 
139 /*
140  * If the number of false interrupts per one transaction exceeds
141  * this threshold, will think there is a GPE storm happened and
142  * will disable the GPE for normal transaction.
143  */
144 static unsigned int ec_storm_threshold  __read_mostly = 8;
145 module_param(ec_storm_threshold, uint, 0644);
146 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
147 
148 struct acpi_ec_query_handler {
149         struct list_head node;
150         acpi_ec_query_func func;
151         acpi_handle handle;
152         void *data;
153         u8 query_bit;
154         struct kref kref;
155 };
156 
157 struct transaction {
158         const u8 *wdata;
159         u8 *rdata;
160         unsigned short irq_count;
161         u8 command;
162         u8 wi;
163         u8 ri;
164         u8 wlen;
165         u8 rlen;
166         u8 flags;
167 };
168 
169 struct acpi_ec_query {
170         struct transaction transaction;
171         struct work_struct work;
172         struct acpi_ec_query_handler *handler;
173 };
174 
175 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
176 static void advance_transaction(struct acpi_ec *ec);
177 static void acpi_ec_event_handler(struct work_struct *work);
178 static void acpi_ec_event_processor(struct work_struct *work);
179 
180 struct acpi_ec *boot_ec, *first_ec;
181 EXPORT_SYMBOL(first_ec);
182 static struct workqueue_struct *ec_query_wq;
183 
184 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
185 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
186 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
187 
188 /* --------------------------------------------------------------------------
189  *                           Logging/Debugging
190  * -------------------------------------------------------------------------- */
191 
192 /*
193  * Splitters used by the developers to track the boundary of the EC
194  * handling processes.
195  */
196 #ifdef DEBUG
197 #define EC_DBG_SEP      " "
198 #define EC_DBG_DRV      "+++++"
199 #define EC_DBG_STM      "====="
200 #define EC_DBG_REQ      "*****"
201 #define EC_DBG_EVT      "#####"
202 #else
203 #define EC_DBG_SEP      ""
204 #define EC_DBG_DRV
205 #define EC_DBG_STM
206 #define EC_DBG_REQ
207 #define EC_DBG_EVT
208 #endif
209 
210 #define ec_log_raw(fmt, ...) \
211         pr_info(fmt "\n", ##__VA_ARGS__)
212 #define ec_dbg_raw(fmt, ...) \
213         pr_debug(fmt "\n", ##__VA_ARGS__)
214 #define ec_log(filter, fmt, ...) \
215         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
216 #define ec_dbg(filter, fmt, ...) \
217         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
218 
219 #define ec_log_drv(fmt, ...) \
220         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
221 #define ec_dbg_drv(fmt, ...) \
222         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
223 #define ec_dbg_stm(fmt, ...) \
224         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
225 #define ec_dbg_req(fmt, ...) \
226         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
227 #define ec_dbg_evt(fmt, ...) \
228         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
229 #define ec_dbg_ref(ec, fmt, ...) \
230         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
231 
232 /* --------------------------------------------------------------------------
233  *                           Device Flags
234  * -------------------------------------------------------------------------- */
235 
236 static bool acpi_ec_started(struct acpi_ec *ec)
237 {
238         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
239                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
240 }
241 
242 static bool acpi_ec_flushed(struct acpi_ec *ec)
243 {
244         return ec->reference_count == 1;
245 }
246 
247 /* --------------------------------------------------------------------------
248  *                           EC Registers
249  * -------------------------------------------------------------------------- */
250 
251 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
252 {
253         u8 x = inb(ec->command_addr);
254 
255         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
256                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
257                    x,
258                    !!(x & ACPI_EC_FLAG_SCI),
259                    !!(x & ACPI_EC_FLAG_BURST),
260                    !!(x & ACPI_EC_FLAG_CMD),
261                    !!(x & ACPI_EC_FLAG_IBF),
262                    !!(x & ACPI_EC_FLAG_OBF));
263         return x;
264 }
265 
266 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
267 {
268         u8 x = inb(ec->data_addr);
269 
270         ec->timestamp = jiffies;
271         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
272         return x;
273 }
274 
275 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
276 {
277         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
278         outb(command, ec->command_addr);
279         ec->timestamp = jiffies;
280 }
281 
282 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
283 {
284         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
285         outb(data, ec->data_addr);
286         ec->timestamp = jiffies;
287 }
288 
289 #ifdef DEBUG
290 static const char *acpi_ec_cmd_string(u8 cmd)
291 {
292         switch (cmd) {
293         case 0x80:
294                 return "RD_EC";
295         case 0x81:
296                 return "WR_EC";
297         case 0x82:
298                 return "BE_EC";
299         case 0x83:
300                 return "BD_EC";
301         case 0x84:
302                 return "QR_EC";
303         }
304         return "UNKNOWN";
305 }
306 #else
307 #define acpi_ec_cmd_string(cmd)         "UNDEF"
308 #endif
309 
310 /* --------------------------------------------------------------------------
311  *                           GPE Registers
312  * -------------------------------------------------------------------------- */
313 
314 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
315 {
316         acpi_event_status gpe_status = 0;
317 
318         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
319         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
320 }
321 
322 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
323 {
324         if (open)
325                 acpi_enable_gpe(NULL, ec->gpe);
326         else {
327                 BUG_ON(ec->reference_count < 1);
328                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
329         }
330         if (acpi_ec_is_gpe_raised(ec)) {
331                 /*
332                  * On some platforms, EN=1 writes cannot trigger GPE. So
333                  * software need to manually trigger a pseudo GPE event on
334                  * EN=1 writes.
335                  */
336                 ec_dbg_raw("Polling quirk");
337                 advance_transaction(ec);
338         }
339 }
340 
341 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
342 {
343         if (close)
344                 acpi_disable_gpe(NULL, ec->gpe);
345         else {
346                 BUG_ON(ec->reference_count < 1);
347                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
348         }
349 }
350 
351 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
352 {
353         /*
354          * GPE STS is a W1C register, which means:
355          * 1. Software can clear it without worrying about clearing other
356          *    GPEs' STS bits when the hardware sets them in parallel.
357          * 2. As long as software can ensure only clearing it when it is
358          *    set, hardware won't set it in parallel.
359          * So software can clear GPE in any contexts.
360          * Warning: do not move the check into advance_transaction() as the
361          * EC commands will be sent without GPE raised.
362          */
363         if (!acpi_ec_is_gpe_raised(ec))
364                 return;
365         acpi_clear_gpe(NULL, ec->gpe);
366 }
367 
368 /* --------------------------------------------------------------------------
369  *                           Transaction Management
370  * -------------------------------------------------------------------------- */
371 
372 static void acpi_ec_submit_request(struct acpi_ec *ec)
373 {
374         ec->reference_count++;
375         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
376             ec->reference_count == 1)
377                 acpi_ec_enable_gpe(ec, true);
378 }
379 
380 static void acpi_ec_complete_request(struct acpi_ec *ec)
381 {
382         bool flushed = false;
383 
384         ec->reference_count--;
385         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
386             ec->reference_count == 0)
387                 acpi_ec_disable_gpe(ec, true);
388         flushed = acpi_ec_flushed(ec);
389         if (flushed)
390                 wake_up(&ec->wait);
391 }
392 
393 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
394 {
395         if (!test_bit(flag, &ec->flags)) {
396                 acpi_ec_disable_gpe(ec, false);
397                 ec_dbg_drv("Polling enabled");
398                 set_bit(flag, &ec->flags);
399         }
400 }
401 
402 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
403 {
404         if (test_bit(flag, &ec->flags)) {
405                 clear_bit(flag, &ec->flags);
406                 acpi_ec_enable_gpe(ec, false);
407                 ec_dbg_drv("Polling disabled");
408         }
409 }
410 
411 /*
412  * acpi_ec_submit_flushable_request() - Increase the reference count unless
413  *                                      the flush operation is not in
414  *                                      progress
415  * @ec: the EC device
416  *
417  * This function must be used before taking a new action that should hold
418  * the reference count.  If this function returns false, then the action
419  * must be discarded or it will prevent the flush operation from being
420  * completed.
421  */
422 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
423 {
424         if (!acpi_ec_started(ec))
425                 return false;
426         acpi_ec_submit_request(ec);
427         return true;
428 }
429 
430 static void acpi_ec_submit_query(struct acpi_ec *ec)
431 {
432         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
433                 ec_dbg_evt("Command(%s) submitted/blocked",
434                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
435                 ec->nr_pending_queries++;
436                 schedule_work(&ec->work);
437         }
438 }
439 
440 static void acpi_ec_complete_query(struct acpi_ec *ec)
441 {
442         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
443                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
444                 ec_dbg_evt("Command(%s) unblocked",
445                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
446         }
447 }
448 
449 static bool acpi_ec_guard_event(struct acpi_ec *ec)
450 {
451         bool guarded = true;
452         unsigned long flags;
453 
454         spin_lock_irqsave(&ec->lock, flags);
455         /*
456          * If firmware SCI_EVT clearing timing is "event", we actually
457          * don't know when the SCI_EVT will be cleared by firmware after
458          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
459          * acceptable period.
460          *
461          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
462          * flagged, which means SCI_EVT check has just been performed.
463          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
464          * guarding should have already been performed (via
465          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
466          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
467          * ACPI_EC_COMMAND_POLL state immediately.
468          */
469         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
470             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
471             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
472             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
473                 guarded = false;
474         spin_unlock_irqrestore(&ec->lock, flags);
475         return guarded;
476 }
477 
478 static int ec_transaction_polled(struct acpi_ec *ec)
479 {
480         unsigned long flags;
481         int ret = 0;
482 
483         spin_lock_irqsave(&ec->lock, flags);
484         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
485                 ret = 1;
486         spin_unlock_irqrestore(&ec->lock, flags);
487         return ret;
488 }
489 
490 static int ec_transaction_completed(struct acpi_ec *ec)
491 {
492         unsigned long flags;
493         int ret = 0;
494 
495         spin_lock_irqsave(&ec->lock, flags);
496         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
497                 ret = 1;
498         spin_unlock_irqrestore(&ec->lock, flags);
499         return ret;
500 }
501 
502 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
503 {
504         ec->curr->flags |= flag;
505         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
506                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
507                     flag == ACPI_EC_COMMAND_POLL)
508                         acpi_ec_complete_query(ec);
509                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
510                     flag == ACPI_EC_COMMAND_COMPLETE)
511                         acpi_ec_complete_query(ec);
512                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
513                     flag == ACPI_EC_COMMAND_COMPLETE)
514                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
515         }
516 }
517 
518 static void advance_transaction(struct acpi_ec *ec)
519 {
520         struct transaction *t;
521         u8 status;
522         bool wakeup = false;
523 
524         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
525                    smp_processor_id());
526         /*
527          * By always clearing STS before handling all indications, we can
528          * ensure a hardware STS 0->1 change after this clearing can always
529          * trigger a GPE interrupt.
530          */
531         acpi_ec_clear_gpe(ec);
532         status = acpi_ec_read_status(ec);
533         t = ec->curr;
534         /*
535          * Another IRQ or a guarded polling mode advancement is detected,
536          * the next QR_EC submission is then allowed.
537          */
538         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
539                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
540                     (!ec->nr_pending_queries ||
541                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
542                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
543                         acpi_ec_complete_query(ec);
544                 }
545         }
546         if (!t)
547                 goto err;
548         if (t->flags & ACPI_EC_COMMAND_POLL) {
549                 if (t->wlen > t->wi) {
550                         if ((status & ACPI_EC_FLAG_IBF) == 0)
551                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
552                         else
553                                 goto err;
554                 } else if (t->rlen > t->ri) {
555                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
556                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
557                                 if (t->rlen == t->ri) {
558                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
559                                         if (t->command == ACPI_EC_COMMAND_QUERY)
560                                                 ec_dbg_evt("Command(%s) completed by hardware",
561                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
562                                         wakeup = true;
563                                 }
564                         } else
565                                 goto err;
566                 } else if (t->wlen == t->wi &&
567                            (status & ACPI_EC_FLAG_IBF) == 0) {
568                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
569                         wakeup = true;
570                 }
571                 goto out;
572         } else {
573                 if (EC_FLAGS_QUERY_HANDSHAKE &&
574                     !(status & ACPI_EC_FLAG_SCI) &&
575                     (t->command == ACPI_EC_COMMAND_QUERY)) {
576                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
577                         t->rdata[t->ri++] = 0x00;
578                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
579                         ec_dbg_evt("Command(%s) completed by software",
580                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
581                         wakeup = true;
582                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
583                         acpi_ec_write_cmd(ec, t->command);
584                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
585                 } else
586                         goto err;
587                 goto out;
588         }
589 err:
590         /*
591          * If SCI bit is set, then don't think it's a false IRQ
592          * otherwise will take a not handled IRQ as a false one.
593          */
594         if (!(status & ACPI_EC_FLAG_SCI)) {
595                 if (in_interrupt() && t) {
596                         if (t->irq_count < ec_storm_threshold)
597                                 ++t->irq_count;
598                         /* Allow triggering on 0 threshold */
599                         if (t->irq_count == ec_storm_threshold)
600                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
601                 }
602         }
603 out:
604         if (status & ACPI_EC_FLAG_SCI)
605                 acpi_ec_submit_query(ec);
606         if (wakeup && in_interrupt())
607                 wake_up(&ec->wait);
608 }
609 
610 static void start_transaction(struct acpi_ec *ec)
611 {
612         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
613         ec->curr->flags = 0;
614 }
615 
616 static int ec_guard(struct acpi_ec *ec)
617 {
618         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
619         unsigned long timeout = ec->timestamp + guard;
620 
621         /* Ensure guarding period before polling EC status */
622         do {
623                 if (ec_busy_polling) {
624                         /* Perform busy polling */
625                         if (ec_transaction_completed(ec))
626                                 return 0;
627                         udelay(jiffies_to_usecs(guard));
628                 } else {
629                         /*
630                          * Perform wait polling
631                          * 1. Wait the transaction to be completed by the
632                          *    GPE handler after the transaction enters
633                          *    ACPI_EC_COMMAND_POLL state.
634                          * 2. A special guarding logic is also required
635                          *    for event clearing mode "event" before the
636                          *    transaction enters ACPI_EC_COMMAND_POLL
637                          *    state.
638                          */
639                         if (!ec_transaction_polled(ec) &&
640                             !acpi_ec_guard_event(ec))
641                                 break;
642                         if (wait_event_timeout(ec->wait,
643                                                ec_transaction_completed(ec),
644                                                guard))
645                                 return 0;
646                 }
647         } while (time_before(jiffies, timeout));
648         return -ETIME;
649 }
650 
651 static int ec_poll(struct acpi_ec *ec)
652 {
653         unsigned long flags;
654         int repeat = 5; /* number of command restarts */
655 
656         while (repeat--) {
657                 unsigned long delay = jiffies +
658                         msecs_to_jiffies(ec_delay);
659                 do {
660                         if (!ec_guard(ec))
661                                 return 0;
662                         spin_lock_irqsave(&ec->lock, flags);
663                         advance_transaction(ec);
664                         spin_unlock_irqrestore(&ec->lock, flags);
665                 } while (time_before(jiffies, delay));
666                 pr_debug("controller reset, restart transaction\n");
667                 spin_lock_irqsave(&ec->lock, flags);
668                 start_transaction(ec);
669                 spin_unlock_irqrestore(&ec->lock, flags);
670         }
671         return -ETIME;
672 }
673 
674 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
675                                         struct transaction *t)
676 {
677         unsigned long tmp;
678         int ret = 0;
679 
680         /* start transaction */
681         spin_lock_irqsave(&ec->lock, tmp);
682         /* Enable GPE for command processing (IBF=0/OBF=1) */
683         if (!acpi_ec_submit_flushable_request(ec)) {
684                 ret = -EINVAL;
685                 goto unlock;
686         }
687         ec_dbg_ref(ec, "Increase command");
688         /* following two actions should be kept atomic */
689         ec->curr = t;
690         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
691         start_transaction(ec);
692         spin_unlock_irqrestore(&ec->lock, tmp);
693 
694         ret = ec_poll(ec);
695 
696         spin_lock_irqsave(&ec->lock, tmp);
697         if (t->irq_count == ec_storm_threshold)
698                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
699         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
700         ec->curr = NULL;
701         /* Disable GPE for command processing (IBF=0/OBF=1) */
702         acpi_ec_complete_request(ec);
703         ec_dbg_ref(ec, "Decrease command");
704 unlock:
705         spin_unlock_irqrestore(&ec->lock, tmp);
706         return ret;
707 }
708 
709 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
710 {
711         int status;
712         u32 glk;
713 
714         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
715                 return -EINVAL;
716         if (t->rdata)
717                 memset(t->rdata, 0, t->rlen);
718 
719         mutex_lock(&ec->mutex);
720         if (ec->global_lock) {
721                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
722                 if (ACPI_FAILURE(status)) {
723                         status = -ENODEV;
724                         goto unlock;
725                 }
726         }
727 
728         status = acpi_ec_transaction_unlocked(ec, t);
729 
730         if (ec->global_lock)
731                 acpi_release_global_lock(glk);
732 unlock:
733         mutex_unlock(&ec->mutex);
734         return status;
735 }
736 
737 static int acpi_ec_burst_enable(struct acpi_ec *ec)
738 {
739         u8 d;
740         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
741                                 .wdata = NULL, .rdata = &d,
742                                 .wlen = 0, .rlen = 1};
743 
744         return acpi_ec_transaction(ec, &t);
745 }
746 
747 static int acpi_ec_burst_disable(struct acpi_ec *ec)
748 {
749         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
750                                 .wdata = NULL, .rdata = NULL,
751                                 .wlen = 0, .rlen = 0};
752 
753         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
754                                 acpi_ec_transaction(ec, &t) : 0;
755 }
756 
757 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
758 {
759         int result;
760         u8 d;
761         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
762                                 .wdata = &address, .rdata = &d,
763                                 .wlen = 1, .rlen = 1};
764 
765         result = acpi_ec_transaction(ec, &t);
766         *data = d;
767         return result;
768 }
769 
770 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
771 {
772         u8 wdata[2] = { address, data };
773         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
774                                 .wdata = wdata, .rdata = NULL,
775                                 .wlen = 2, .rlen = 0};
776 
777         return acpi_ec_transaction(ec, &t);
778 }
779 
780 int ec_read(u8 addr, u8 *val)
781 {
782         int err;
783         u8 temp_data;
784 
785         if (!first_ec)
786                 return -ENODEV;
787 
788         err = acpi_ec_read(first_ec, addr, &temp_data);
789 
790         if (!err) {
791                 *val = temp_data;
792                 return 0;
793         }
794         return err;
795 }
796 EXPORT_SYMBOL(ec_read);
797 
798 int ec_write(u8 addr, u8 val)
799 {
800         int err;
801 
802         if (!first_ec)
803                 return -ENODEV;
804 
805         err = acpi_ec_write(first_ec, addr, val);
806 
807         return err;
808 }
809 EXPORT_SYMBOL(ec_write);
810 
811 int ec_transaction(u8 command,
812                    const u8 *wdata, unsigned wdata_len,
813                    u8 *rdata, unsigned rdata_len)
814 {
815         struct transaction t = {.command = command,
816                                 .wdata = wdata, .rdata = rdata,
817                                 .wlen = wdata_len, .rlen = rdata_len};
818 
819         if (!first_ec)
820                 return -ENODEV;
821 
822         return acpi_ec_transaction(first_ec, &t);
823 }
824 EXPORT_SYMBOL(ec_transaction);
825 
826 /* Get the handle to the EC device */
827 acpi_handle ec_get_handle(void)
828 {
829         if (!first_ec)
830                 return NULL;
831         return first_ec->handle;
832 }
833 EXPORT_SYMBOL(ec_get_handle);
834 
835 /*
836  * Process _Q events that might have accumulated in the EC.
837  * Run with locked ec mutex.
838  */
839 static void acpi_ec_clear(struct acpi_ec *ec)
840 {
841         int i, status;
842         u8 value = 0;
843 
844         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
845                 status = acpi_ec_query(ec, &value);
846                 if (status || !value)
847                         break;
848         }
849 
850         if (unlikely(i == ACPI_EC_CLEAR_MAX))
851                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
852         else
853                 pr_info("%d stale EC events cleared\n", i);
854 }
855 
856 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
857 {
858         unsigned long flags;
859 
860         spin_lock_irqsave(&ec->lock, flags);
861         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
862                 ec_dbg_drv("Starting EC");
863                 /* Enable GPE for event processing (SCI_EVT=1) */
864                 if (!resuming) {
865                         acpi_ec_submit_request(ec);
866                         ec_dbg_ref(ec, "Increase driver");
867                 }
868                 ec_log_drv("EC started");
869         }
870         spin_unlock_irqrestore(&ec->lock, flags);
871 }
872 
873 static bool acpi_ec_stopped(struct acpi_ec *ec)
874 {
875         unsigned long flags;
876         bool flushed;
877 
878         spin_lock_irqsave(&ec->lock, flags);
879         flushed = acpi_ec_flushed(ec);
880         spin_unlock_irqrestore(&ec->lock, flags);
881         return flushed;
882 }
883 
884 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
885 {
886         unsigned long flags;
887 
888         spin_lock_irqsave(&ec->lock, flags);
889         if (acpi_ec_started(ec)) {
890                 ec_dbg_drv("Stopping EC");
891                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
892                 spin_unlock_irqrestore(&ec->lock, flags);
893                 wait_event(ec->wait, acpi_ec_stopped(ec));
894                 spin_lock_irqsave(&ec->lock, flags);
895                 /* Disable GPE for event processing (SCI_EVT=1) */
896                 if (!suspending) {
897                         acpi_ec_complete_request(ec);
898                         ec_dbg_ref(ec, "Decrease driver");
899                 }
900                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
901                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
902                 ec_log_drv("EC stopped");
903         }
904         spin_unlock_irqrestore(&ec->lock, flags);
905 }
906 
907 void acpi_ec_block_transactions(void)
908 {
909         struct acpi_ec *ec = first_ec;
910 
911         if (!ec)
912                 return;
913 
914         mutex_lock(&ec->mutex);
915         /* Prevent transactions from being carried out */
916         acpi_ec_stop(ec, true);
917         mutex_unlock(&ec->mutex);
918 }
919 
920 void acpi_ec_unblock_transactions(void)
921 {
922         struct acpi_ec *ec = first_ec;
923 
924         if (!ec)
925                 return;
926 
927         /* Allow transactions to be carried out again */
928         acpi_ec_start(ec, true);
929 
930         if (EC_FLAGS_CLEAR_ON_RESUME)
931                 acpi_ec_clear(ec);
932 }
933 
934 void acpi_ec_unblock_transactions_early(void)
935 {
936         /*
937          * Allow transactions to happen again (this function is called from
938          * atomic context during wakeup, so we don't need to acquire the mutex).
939          */
940         if (first_ec)
941                 acpi_ec_start(first_ec, true);
942 }
943 
944 /* --------------------------------------------------------------------------
945                                 Event Management
946    -------------------------------------------------------------------------- */
947 static struct acpi_ec_query_handler *
948 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
949 {
950         if (handler)
951                 kref_get(&handler->kref);
952         return handler;
953 }
954 
955 static struct acpi_ec_query_handler *
956 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
957 {
958         struct acpi_ec_query_handler *handler;
959         bool found = false;
960 
961         mutex_lock(&ec->mutex);
962         list_for_each_entry(handler, &ec->list, node) {
963                 if (value == handler->query_bit) {
964                         found = true;
965                         break;
966                 }
967         }
968         mutex_unlock(&ec->mutex);
969         return found ? acpi_ec_get_query_handler(handler) : NULL;
970 }
971 
972 static void acpi_ec_query_handler_release(struct kref *kref)
973 {
974         struct acpi_ec_query_handler *handler =
975                 container_of(kref, struct acpi_ec_query_handler, kref);
976 
977         kfree(handler);
978 }
979 
980 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
981 {
982         kref_put(&handler->kref, acpi_ec_query_handler_release);
983 }
984 
985 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
986                               acpi_handle handle, acpi_ec_query_func func,
987                               void *data)
988 {
989         struct acpi_ec_query_handler *handler =
990             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
991 
992         if (!handler)
993                 return -ENOMEM;
994 
995         handler->query_bit = query_bit;
996         handler->handle = handle;
997         handler->func = func;
998         handler->data = data;
999         mutex_lock(&ec->mutex);
1000         kref_init(&handler->kref);
1001         list_add(&handler->node, &ec->list);
1002         mutex_unlock(&ec->mutex);
1003         return 0;
1004 }
1005 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1006 
1007 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1008                                           bool remove_all, u8 query_bit)
1009 {
1010         struct acpi_ec_query_handler *handler, *tmp;
1011         LIST_HEAD(free_list);
1012 
1013         mutex_lock(&ec->mutex);
1014         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1015                 if (remove_all || query_bit == handler->query_bit) {
1016                         list_del_init(&handler->node);
1017                         list_add(&handler->node, &free_list);
1018                 }
1019         }
1020         mutex_unlock(&ec->mutex);
1021         list_for_each_entry_safe(handler, tmp, &free_list, node)
1022                 acpi_ec_put_query_handler(handler);
1023 }
1024 
1025 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1026 {
1027         acpi_ec_remove_query_handlers(ec, false, query_bit);
1028 }
1029 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1030 
1031 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1032 {
1033         struct acpi_ec_query *q;
1034         struct transaction *t;
1035 
1036         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1037         if (!q)
1038                 return NULL;
1039         INIT_WORK(&q->work, acpi_ec_event_processor);
1040         t = &q->transaction;
1041         t->command = ACPI_EC_COMMAND_QUERY;
1042         t->rdata = pval;
1043         t->rlen = 1;
1044         return q;
1045 }
1046 
1047 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1048 {
1049         if (q) {
1050                 if (q->handler)
1051                         acpi_ec_put_query_handler(q->handler);
1052                 kfree(q);
1053         }
1054 }
1055 
1056 static void acpi_ec_event_processor(struct work_struct *work)
1057 {
1058         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1059         struct acpi_ec_query_handler *handler = q->handler;
1060 
1061         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1062         if (handler->func)
1063                 handler->func(handler->data);
1064         else if (handler->handle)
1065                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1066         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1067         acpi_ec_delete_query(q);
1068 }
1069 
1070 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1071 {
1072         u8 value = 0;
1073         int result;
1074         struct acpi_ec_query *q;
1075 
1076         q = acpi_ec_create_query(&value);
1077         if (!q)
1078                 return -ENOMEM;
1079 
1080         /*
1081          * Query the EC to find out which _Qxx method we need to evaluate.
1082          * Note that successful completion of the query causes the ACPI_EC_SCI
1083          * bit to be cleared (and thus clearing the interrupt source).
1084          */
1085         result = acpi_ec_transaction(ec, &q->transaction);
1086         if (!value)
1087                 result = -ENODATA;
1088         if (result)
1089                 goto err_exit;
1090 
1091         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1092         if (!q->handler) {
1093                 result = -ENODATA;
1094                 goto err_exit;
1095         }
1096 
1097         /*
1098          * It is reported that _Qxx are evaluated in a parallel way on
1099          * Windows:
1100          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1101          *
1102          * Put this log entry before schedule_work() in order to make
1103          * it appearing before any other log entries occurred during the
1104          * work queue execution.
1105          */
1106         ec_dbg_evt("Query(0x%02x) scheduled", value);
1107         if (!queue_work(ec_query_wq, &q->work)) {
1108                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1109                 result = -EBUSY;
1110         }
1111 
1112 err_exit:
1113         if (result)
1114                 acpi_ec_delete_query(q);
1115         if (data)
1116                 *data = value;
1117         return result;
1118 }
1119 
1120 static void acpi_ec_check_event(struct acpi_ec *ec)
1121 {
1122         unsigned long flags;
1123 
1124         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1125                 if (ec_guard(ec)) {
1126                         spin_lock_irqsave(&ec->lock, flags);
1127                         /*
1128                          * Take care of the SCI_EVT unless no one else is
1129                          * taking care of it.
1130                          */
1131                         if (!ec->curr)
1132                                 advance_transaction(ec);
1133                         spin_unlock_irqrestore(&ec->lock, flags);
1134                 }
1135         }
1136 }
1137 
1138 static void acpi_ec_event_handler(struct work_struct *work)
1139 {
1140         unsigned long flags;
1141         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1142 
1143         ec_dbg_evt("Event started");
1144 
1145         spin_lock_irqsave(&ec->lock, flags);
1146         while (ec->nr_pending_queries) {
1147                 spin_unlock_irqrestore(&ec->lock, flags);
1148                 (void)acpi_ec_query(ec, NULL);
1149                 spin_lock_irqsave(&ec->lock, flags);
1150                 ec->nr_pending_queries--;
1151                 /*
1152                  * Before exit, make sure that this work item can be
1153                  * scheduled again. There might be QR_EC failures, leaving
1154                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1155                  * item from being scheduled again.
1156                  */
1157                 if (!ec->nr_pending_queries) {
1158                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1159                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1160                                 acpi_ec_complete_query(ec);
1161                 }
1162         }
1163         spin_unlock_irqrestore(&ec->lock, flags);
1164 
1165         ec_dbg_evt("Event stopped");
1166 
1167         acpi_ec_check_event(ec);
1168 }
1169 
1170 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1171         u32 gpe_number, void *data)
1172 {
1173         unsigned long flags;
1174         struct acpi_ec *ec = data;
1175 
1176         spin_lock_irqsave(&ec->lock, flags);
1177         advance_transaction(ec);
1178         spin_unlock_irqrestore(&ec->lock, flags);
1179         return ACPI_INTERRUPT_HANDLED;
1180 }
1181 
1182 /* --------------------------------------------------------------------------
1183  *                           Address Space Management
1184  * -------------------------------------------------------------------------- */
1185 
1186 static acpi_status
1187 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1188                       u32 bits, u64 *value64,
1189                       void *handler_context, void *region_context)
1190 {
1191         struct acpi_ec *ec = handler_context;
1192         int result = 0, i, bytes = bits / 8;
1193         u8 *value = (u8 *)value64;
1194 
1195         if ((address > 0xFF) || !value || !handler_context)
1196                 return AE_BAD_PARAMETER;
1197 
1198         if (function != ACPI_READ && function != ACPI_WRITE)
1199                 return AE_BAD_PARAMETER;
1200 
1201         if (ec_busy_polling || bits > 8)
1202                 acpi_ec_burst_enable(ec);
1203 
1204         for (i = 0; i < bytes; ++i, ++address, ++value)
1205                 result = (function == ACPI_READ) ?
1206                         acpi_ec_read(ec, address, value) :
1207                         acpi_ec_write(ec, address, *value);
1208 
1209         if (ec_busy_polling || bits > 8)
1210                 acpi_ec_burst_disable(ec);
1211 
1212         switch (result) {
1213         case -EINVAL:
1214                 return AE_BAD_PARAMETER;
1215         case -ENODEV:
1216                 return AE_NOT_FOUND;
1217         case -ETIME:
1218                 return AE_TIME;
1219         default:
1220                 return AE_OK;
1221         }
1222 }
1223 
1224 /* --------------------------------------------------------------------------
1225  *                             Driver Interface
1226  * -------------------------------------------------------------------------- */
1227 
1228 static acpi_status
1229 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1230 
1231 static struct acpi_ec *make_acpi_ec(void)
1232 {
1233         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1234 
1235         if (!ec)
1236                 return NULL;
1237         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1238         mutex_init(&ec->mutex);
1239         init_waitqueue_head(&ec->wait);
1240         INIT_LIST_HEAD(&ec->list);
1241         spin_lock_init(&ec->lock);
1242         INIT_WORK(&ec->work, acpi_ec_event_handler);
1243         ec->timestamp = jiffies;
1244         return ec;
1245 }
1246 
1247 static acpi_status
1248 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1249                                void *context, void **return_value)
1250 {
1251         char node_name[5];
1252         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1253         struct acpi_ec *ec = context;
1254         int value = 0;
1255         acpi_status status;
1256 
1257         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1258 
1259         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1260                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1261         return AE_OK;
1262 }
1263 
1264 static acpi_status
1265 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1266 {
1267         acpi_status status;
1268         unsigned long long tmp = 0;
1269         struct acpi_ec *ec = context;
1270 
1271         /* clear addr values, ec_parse_io_ports depend on it */
1272         ec->command_addr = ec->data_addr = 0;
1273 
1274         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1275                                      ec_parse_io_ports, ec);
1276         if (ACPI_FAILURE(status))
1277                 return status;
1278 
1279         /* Get GPE bit assignment (EC events). */
1280         /* TODO: Add support for _GPE returning a package */
1281         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1282         if (ACPI_FAILURE(status))
1283                 return status;
1284         ec->gpe = tmp;
1285         /* Use the global lock for all EC transactions? */
1286         tmp = 0;
1287         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1288         ec->global_lock = tmp;
1289         ec->handle = handle;
1290         return AE_CTRL_TERMINATE;
1291 }
1292 
1293 static int ec_install_handlers(struct acpi_ec *ec)
1294 {
1295         acpi_status status;
1296 
1297         acpi_ec_start(ec, false);
1298 
1299         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1300                 status = acpi_install_address_space_handler(ec->handle,
1301                                                             ACPI_ADR_SPACE_EC,
1302                                                             &acpi_ec_space_handler,
1303                                                             NULL, ec);
1304                 if (ACPI_FAILURE(status)) {
1305                         if (status == AE_NOT_FOUND) {
1306                                 /*
1307                                  * Maybe OS fails in evaluating the _REG
1308                                  * object. The AE_NOT_FOUND error will be
1309                                  * ignored and OS * continue to initialize
1310                                  * EC.
1311                                  */
1312                                 pr_err("Fail in evaluating the _REG object"
1313                                         " of EC device. Broken bios is suspected.\n");
1314                         } else {
1315                                 acpi_ec_stop(ec, false);
1316                                 return -ENODEV;
1317                         }
1318                 }
1319                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1320         }
1321 
1322         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1323                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1324                                           ACPI_GPE_EDGE_TRIGGERED,
1325                                           &acpi_ec_gpe_handler, ec);
1326                 /* This is not fatal as we can poll EC events */
1327                 if (ACPI_SUCCESS(status)) {
1328                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1329                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1330                             ec->reference_count >= 1)
1331                                 acpi_ec_enable_gpe(ec, true);
1332                 }
1333         }
1334 
1335         return 0;
1336 }
1337 
1338 static void ec_remove_handlers(struct acpi_ec *ec)
1339 {
1340         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1341                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1342                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1343                         pr_err("failed to remove space handler\n");
1344                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1345         }
1346 
1347         /*
1348          * Stops handling the EC transactions after removing the operation
1349          * region handler. This is required because _REG(DISCONNECT)
1350          * invoked during the removal can result in new EC transactions.
1351          *
1352          * Flushes the EC requests and thus disables the GPE before
1353          * removing the GPE handler. This is required by the current ACPICA
1354          * GPE core. ACPICA GPE core will automatically disable a GPE when
1355          * it is indicated but there is no way to handle it. So the drivers
1356          * must disable the GPEs prior to removing the GPE handlers.
1357          */
1358         acpi_ec_stop(ec, false);
1359 
1360         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1361                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1362                                         &acpi_ec_gpe_handler)))
1363                         pr_err("failed to remove gpe handler\n");
1364                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1365         }
1366 }
1367 
1368 static struct acpi_ec *acpi_ec_alloc(void)
1369 {
1370         struct acpi_ec *ec;
1371 
1372         /* Check for boot EC */
1373         if (boot_ec) {
1374                 ec = boot_ec;
1375                 boot_ec = NULL;
1376                 ec_remove_handlers(ec);
1377                 if (first_ec == ec)
1378                         first_ec = NULL;
1379         } else {
1380                 ec = make_acpi_ec();
1381         }
1382         return ec;
1383 }
1384 
1385 static int acpi_ec_add(struct acpi_device *device)
1386 {
1387         struct acpi_ec *ec = NULL;
1388         int ret;
1389 
1390         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1391         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1392 
1393         ec = acpi_ec_alloc();
1394         if (!ec)
1395                 return -ENOMEM;
1396         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1397                 AE_CTRL_TERMINATE) {
1398                         kfree(ec);
1399                         return -EINVAL;
1400         }
1401 
1402         /* Find and register all query methods */
1403         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1404                             acpi_ec_register_query_methods, NULL, ec, NULL);
1405 
1406         if (!first_ec)
1407                 first_ec = ec;
1408         device->driver_data = ec;
1409 
1410         ret = !!request_region(ec->data_addr, 1, "EC data");
1411         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1412         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1413         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1414 
1415         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1416                           ec->gpe, ec->command_addr, ec->data_addr);
1417 
1418         ret = ec_install_handlers(ec);
1419 
1420         /* Reprobe devices depending on the EC */
1421         acpi_walk_dep_device_list(ec->handle);
1422 
1423         /* EC is fully operational, allow queries */
1424         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1425 
1426         /* Clear stale _Q events if hardware might require that */
1427         if (EC_FLAGS_CLEAR_ON_RESUME)
1428                 acpi_ec_clear(ec);
1429         return ret;
1430 }
1431 
1432 static int acpi_ec_remove(struct acpi_device *device)
1433 {
1434         struct acpi_ec *ec;
1435 
1436         if (!device)
1437                 return -EINVAL;
1438 
1439         ec = acpi_driver_data(device);
1440         ec_remove_handlers(ec);
1441         acpi_ec_remove_query_handlers(ec, true, 0);
1442         release_region(ec->data_addr, 1);
1443         release_region(ec->command_addr, 1);
1444         device->driver_data = NULL;
1445         if (ec == first_ec)
1446                 first_ec = NULL;
1447         kfree(ec);
1448         return 0;
1449 }
1450 
1451 static acpi_status
1452 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1453 {
1454         struct acpi_ec *ec = context;
1455 
1456         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1457                 return AE_OK;
1458 
1459         /*
1460          * The first address region returned is the data port, and
1461          * the second address region returned is the status/command
1462          * port.
1463          */
1464         if (ec->data_addr == 0)
1465                 ec->data_addr = resource->data.io.minimum;
1466         else if (ec->command_addr == 0)
1467                 ec->command_addr = resource->data.io.minimum;
1468         else
1469                 return AE_CTRL_TERMINATE;
1470 
1471         return AE_OK;
1472 }
1473 
1474 static const struct acpi_device_id ec_device_ids[] = {
1475         {"PNP0C09", 0},
1476         {"", 0},
1477 };
1478 
1479 int __init acpi_ec_dsdt_probe(void)
1480 {
1481         acpi_status status;
1482         struct acpi_ec *ec;
1483         int ret;
1484 
1485         ec = acpi_ec_alloc();
1486         if (!ec)
1487                 return -ENOMEM;
1488         /*
1489          * Finding EC from DSDT if there is no ECDT EC available. When this
1490          * function is invoked, ACPI tables have been fully loaded, we can
1491          * walk namespace now.
1492          */
1493         status = acpi_get_devices(ec_device_ids[0].id,
1494                                   ec_parse_device, ec, NULL);
1495         if (ACPI_FAILURE(status) || !ec->handle) {
1496                 ret = -ENODEV;
1497                 goto error;
1498         }
1499         ret = ec_install_handlers(ec);
1500 
1501 error:
1502         if (ret)
1503                 kfree(ec);
1504         else
1505                 first_ec = boot_ec = ec;
1506         return ret;
1507 }
1508 
1509 #if 0
1510 /*
1511  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1512  * set, for which case, we complete the QR_EC without issuing it to the
1513  * firmware.
1514  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1515  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1516  */
1517 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1518 {
1519         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1520         EC_FLAGS_QUERY_HANDSHAKE = 1;
1521         return 0;
1522 }
1523 #endif
1524 
1525 /*
1526  * On some hardware it is necessary to clear events accumulated by the EC during
1527  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1528  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1529  *
1530  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1531  *
1532  * Ideally, the EC should also be instructed NOT to accumulate events during
1533  * sleep (which Windows seems to do somehow), but the interface to control this
1534  * behaviour is not known at this time.
1535  *
1536  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1537  * however it is very likely that other Samsung models are affected.
1538  *
1539  * On systems which don't accumulate _Q events during sleep, this extra check
1540  * should be harmless.
1541  */
1542 static int ec_clear_on_resume(const struct dmi_system_id *id)
1543 {
1544         pr_debug("Detected system needing EC poll on resume.\n");
1545         EC_FLAGS_CLEAR_ON_RESUME = 1;
1546         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1547         return 0;
1548 }
1549 
1550 /*
1551  * Some ECDTs contain wrong register addresses.
1552  * MSI MS-171F
1553  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1554  */
1555 static int ec_correct_ecdt(const struct dmi_system_id *id)
1556 {
1557         pr_debug("Detected system needing ECDT address correction.\n");
1558         EC_FLAGS_CORRECT_ECDT = 1;
1559         return 0;
1560 }
1561 
1562 static struct dmi_system_id ec_dmi_table[] __initdata = {
1563         {
1564         ec_correct_ecdt, "MSI MS-171F", {
1565         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1566         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1567         {
1568         ec_clear_on_resume, "Samsung hardware", {
1569         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1570         {},
1571 };
1572 
1573 int __init acpi_ec_ecdt_probe(void)
1574 {
1575         int ret;
1576         acpi_status status;
1577         struct acpi_table_ecdt *ecdt_ptr;
1578         struct acpi_ec *ec;
1579 
1580         ec = acpi_ec_alloc();
1581         if (!ec)
1582                 return -ENOMEM;
1583         /*
1584          * Generate a boot ec context
1585          */
1586         dmi_check_system(ec_dmi_table);
1587         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1588                                 (struct acpi_table_header **)&ecdt_ptr);
1589         if (ACPI_FAILURE(status)) {
1590                 ret = -ENODEV;
1591                 goto error;
1592         }
1593 
1594         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1595                 /*
1596                  * Asus X50GL:
1597                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1598                  */
1599                 ret = -ENODEV;
1600                 goto error;
1601         }
1602 
1603         pr_info("EC description table is found, configuring boot EC\n");
1604         if (EC_FLAGS_CORRECT_ECDT) {
1605                 ec->command_addr = ecdt_ptr->data.address;
1606                 ec->data_addr = ecdt_ptr->control.address;
1607         } else {
1608                 ec->command_addr = ecdt_ptr->control.address;
1609                 ec->data_addr = ecdt_ptr->data.address;
1610         }
1611         ec->gpe = ecdt_ptr->gpe;
1612         ec->handle = ACPI_ROOT_OBJECT;
1613         ret = ec_install_handlers(ec);
1614 error:
1615         if (ret)
1616                 kfree(ec);
1617         else
1618                 first_ec = boot_ec = ec;
1619         return ret;
1620 }
1621 
1622 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1623 {
1624         int result = 0;
1625 
1626         if (!strncmp(val, "status", sizeof("status") - 1)) {
1627                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1628                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1629         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1630                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1631                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1632         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1633                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1634                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1635         } else
1636                 result = -EINVAL;
1637         return result;
1638 }
1639 
1640 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1641 {
1642         switch (ec_event_clearing) {
1643         case ACPI_EC_EVT_TIMING_STATUS:
1644                 return sprintf(buffer, "status");
1645         case ACPI_EC_EVT_TIMING_QUERY:
1646                 return sprintf(buffer, "query");
1647         case ACPI_EC_EVT_TIMING_EVENT:
1648                 return sprintf(buffer, "event");
1649         default:
1650                 return sprintf(buffer, "invalid");
1651         }
1652         return 0;
1653 }
1654 
1655 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1656                   NULL, 0644);
1657 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1658 
1659 static struct acpi_driver acpi_ec_driver = {
1660         .name = "ec",
1661         .class = ACPI_EC_CLASS,
1662         .ids = ec_device_ids,
1663         .ops = {
1664                 .add = acpi_ec_add,
1665                 .remove = acpi_ec_remove,
1666                 },
1667 };
1668 
1669 static inline int acpi_ec_query_init(void)
1670 {
1671         if (!ec_query_wq) {
1672                 ec_query_wq = alloc_workqueue("kec_query", 0,
1673                                               ec_max_queries);
1674                 if (!ec_query_wq)
1675                         return -ENODEV;
1676         }
1677         return 0;
1678 }
1679 
1680 static inline void acpi_ec_query_exit(void)
1681 {
1682         if (ec_query_wq) {
1683                 destroy_workqueue(ec_query_wq);
1684                 ec_query_wq = NULL;
1685         }
1686 }
1687 
1688 int __init acpi_ec_init(void)
1689 {
1690         int result;
1691 
1692         /* register workqueue for _Qxx evaluations */
1693         result = acpi_ec_query_init();
1694         if (result)
1695                 goto err_exit;
1696         /* Now register the driver for the EC */
1697         result = acpi_bus_register_driver(&acpi_ec_driver);
1698         if (result)
1699                 goto err_exit;
1700 
1701 err_exit:
1702         if (result)
1703                 acpi_ec_query_exit();
1704         return result;
1705 }
1706 
1707 /* EC driver currently not unloadable */
1708 #if 0
1709 static void __exit acpi_ec_exit(void)
1710 {
1711 
1712         acpi_bus_unregister_driver(&acpi_ec_driver);
1713         acpi_ec_query_exit();
1714 }
1715 #endif  /* 0 */
1716 

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