GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / acpi / ec.c
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v3)
3  *
4  *  Copyright (C) 2001-2015 Intel Corporation
5  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
6  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
7  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
8  *            2004       Luming Yu <luming.yu@intel.com>
9  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
10  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
11  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
12  *
13  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
14  *
15  *  This program is free software; you can redistribute it and/or modify
16  *  it under the terms of the GNU General Public License as published by
17  *  the Free Software Foundation; either version 2 of the License, or (at
18  *  your option) any later version.
19  *
20  *  This program is distributed in the hope that it will be useful, but
21  *  WITHOUT ANY WARRANTY; without even the implied warranty of
22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23  *  General Public License for more details.
24  *
25  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
26  */
27
28 /* Uncomment next line to get verbose printout */
29 /* #define DEBUG */
30 #define pr_fmt(fmt) "ACPI : EC: " fmt
31
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/init.h>
35 #include <linux/types.h>
36 #include <linux/delay.h>
37 #include <linux/interrupt.h>
38 #include <linux/list.h>
39 #include <linux/spinlock.h>
40 #include <linux/slab.h>
41 #include <linux/acpi.h>
42 #include <linux/dmi.h>
43 #include <asm/io.h>
44
45 #include "internal.h"
46
47 #define ACPI_EC_CLASS                   "embedded_controller"
48 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
49 #define ACPI_EC_FILE_INFO               "info"
50
51 /* EC status register */
52 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
53 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
54 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
55 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
56 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
57
58 /*
59  * The SCI_EVT clearing timing is not defined by the ACPI specification.
60  * This leads to lots of practical timing issues for the host EC driver.
61  * The following variations are defined (from the target EC firmware's
62  * perspective):
63  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
64  *         target can clear SCI_EVT at any time so long as the host can see
65  *         the indication by reading the status register (EC_SC). So the
66  *         host should re-check SCI_EVT after the first time the SCI_EVT
67  *         indication is seen, which is the same time the query request
68  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
69  *         at any later time could indicate another event. Normally such
70  *         kind of EC firmware has implemented an event queue and will
71  *         return 0x00 to indicate "no outstanding event".
72  * QUERY: After seeing the query request (QR_EC) written to the command
73  *        register (EC_CMD) by the host and having prepared the responding
74  *        event value in the data register (EC_DATA), the target can safely
75  *        clear SCI_EVT because the target can confirm that the current
76  *        event is being handled by the host. The host then should check
77  *        SCI_EVT right after reading the event response from the data
78  *        register (EC_DATA).
79  * EVENT: After seeing the event response read from the data register
80  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
81  *        target requires time to notice the change in the data register
82  *        (EC_DATA), the host may be required to wait additional guarding
83  *        time before checking the SCI_EVT again. Such guarding may not be
84  *        necessary if the host is notified via another IRQ.
85  */
86 #define ACPI_EC_EVT_TIMING_STATUS       0x00
87 #define ACPI_EC_EVT_TIMING_QUERY        0x01
88 #define ACPI_EC_EVT_TIMING_EVENT        0x02
89
90 /* EC commands */
91 enum ec_command {
92         ACPI_EC_COMMAND_READ = 0x80,
93         ACPI_EC_COMMAND_WRITE = 0x81,
94         ACPI_EC_BURST_ENABLE = 0x82,
95         ACPI_EC_BURST_DISABLE = 0x83,
96         ACPI_EC_COMMAND_QUERY = 0x84,
97 };
98
99 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
100 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
101 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
102 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
103                                          * when trying to clear the EC */
104 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
105
106 enum {
107         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
108         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
109         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
110                                          * OpReg are 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_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
185 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
186 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
187 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
188
189 /* --------------------------------------------------------------------------
190  *                           Logging/Debugging
191  * -------------------------------------------------------------------------- */
192
193 /*
194  * Splitters used by the developers to track the boundary of the EC
195  * handling processes.
196  */
197 #ifdef DEBUG
198 #define EC_DBG_SEP      " "
199 #define EC_DBG_DRV      "+++++"
200 #define EC_DBG_STM      "====="
201 #define EC_DBG_REQ      "*****"
202 #define EC_DBG_EVT      "#####"
203 #else
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 #endif
210
211 #define ec_log_raw(fmt, ...) \
212         pr_info(fmt "\n", ##__VA_ARGS__)
213 #define ec_dbg_raw(fmt, ...) \
214         pr_debug(fmt "\n", ##__VA_ARGS__)
215 #define ec_log(filter, fmt, ...) \
216         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
217 #define ec_dbg(filter, fmt, ...) \
218         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
219
220 #define ec_log_drv(fmt, ...) \
221         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
222 #define ec_dbg_drv(fmt, ...) \
223         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
224 #define ec_dbg_stm(fmt, ...) \
225         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
226 #define ec_dbg_req(fmt, ...) \
227         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
228 #define ec_dbg_evt(fmt, ...) \
229         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
230 #define ec_dbg_ref(ec, fmt, ...) \
231         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
232
233 /* --------------------------------------------------------------------------
234  *                           Device Flags
235  * -------------------------------------------------------------------------- */
236
237 static bool acpi_ec_started(struct acpi_ec *ec)
238 {
239         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
240                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
241 }
242
243 static bool acpi_ec_flushed(struct acpi_ec *ec)
244 {
245         return ec->reference_count == 1;
246 }
247
248 /* --------------------------------------------------------------------------
249  *                           EC Registers
250  * -------------------------------------------------------------------------- */
251
252 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
253 {
254         u8 x = inb(ec->command_addr);
255
256         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
257                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
258                    x,
259                    !!(x & ACPI_EC_FLAG_SCI),
260                    !!(x & ACPI_EC_FLAG_BURST),
261                    !!(x & ACPI_EC_FLAG_CMD),
262                    !!(x & ACPI_EC_FLAG_IBF),
263                    !!(x & ACPI_EC_FLAG_OBF));
264         return x;
265 }
266
267 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
268 {
269         u8 x = inb(ec->data_addr);
270
271         ec->timestamp = jiffies;
272         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
273         return x;
274 }
275
276 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
277 {
278         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
279         outb(command, ec->command_addr);
280         ec->timestamp = jiffies;
281 }
282
283 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
284 {
285         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
286         outb(data, ec->data_addr);
287         ec->timestamp = jiffies;
288 }
289
290 #ifdef DEBUG
291 static const char *acpi_ec_cmd_string(u8 cmd)
292 {
293         switch (cmd) {
294         case 0x80:
295                 return "RD_EC";
296         case 0x81:
297                 return "WR_EC";
298         case 0x82:
299                 return "BE_EC";
300         case 0x83:
301                 return "BD_EC";
302         case 0x84:
303                 return "QR_EC";
304         }
305         return "UNKNOWN";
306 }
307 #else
308 #define acpi_ec_cmd_string(cmd)         "UNDEF"
309 #endif
310
311 /* --------------------------------------------------------------------------
312  *                           GPE Registers
313  * -------------------------------------------------------------------------- */
314
315 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
316 {
317         acpi_event_status gpe_status = 0;
318
319         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
320         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
321 }
322
323 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
324 {
325         if (open)
326                 acpi_enable_gpe(NULL, ec->gpe);
327         else {
328                 BUG_ON(ec->reference_count < 1);
329                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
330         }
331         if (acpi_ec_is_gpe_raised(ec)) {
332                 /*
333                  * On some platforms, EN=1 writes cannot trigger GPE. So
334                  * software need to manually trigger a pseudo GPE event on
335                  * EN=1 writes.
336                  */
337                 ec_dbg_raw("Polling quirk");
338                 advance_transaction(ec);
339         }
340 }
341
342 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
343 {
344         if (close)
345                 acpi_disable_gpe(NULL, ec->gpe);
346         else {
347                 BUG_ON(ec->reference_count < 1);
348                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
349         }
350 }
351
352 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
353 {
354         /*
355          * GPE STS is a W1C register, which means:
356          * 1. Software can clear it without worrying about clearing other
357          *    GPEs' STS bits when the hardware sets them in parallel.
358          * 2. As long as software can ensure only clearing it when it is
359          *    set, hardware won't set it in parallel.
360          * So software can clear GPE in any contexts.
361          * Warning: do not move the check into advance_transaction() as the
362          * EC commands will be sent without GPE raised.
363          */
364         if (!acpi_ec_is_gpe_raised(ec))
365                 return;
366         acpi_clear_gpe(NULL, ec->gpe);
367 }
368
369 /* --------------------------------------------------------------------------
370  *                           Transaction Management
371  * -------------------------------------------------------------------------- */
372
373 static void acpi_ec_submit_request(struct acpi_ec *ec)
374 {
375         ec->reference_count++;
376         if (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 (ec->reference_count == 0)
386                 acpi_ec_disable_gpe(ec, true);
387         flushed = acpi_ec_flushed(ec);
388         if (flushed)
389                 wake_up(&ec->wait);
390 }
391
392 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
393 {
394         if (!test_bit(flag, &ec->flags)) {
395                 acpi_ec_disable_gpe(ec, false);
396                 ec_dbg_drv("Polling enabled");
397                 set_bit(flag, &ec->flags);
398         }
399 }
400
401 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
402 {
403         if (test_bit(flag, &ec->flags)) {
404                 clear_bit(flag, &ec->flags);
405                 acpi_ec_enable_gpe(ec, false);
406                 ec_dbg_drv("Polling disabled");
407         }
408 }
409
410 /*
411  * acpi_ec_submit_flushable_request() - Increase the reference count unless
412  *                                      the flush operation is not in
413  *                                      progress
414  * @ec: the EC device
415  *
416  * This function must be used before taking a new action that should hold
417  * the reference count.  If this function returns false, then the action
418  * must be discarded or it will prevent the flush operation from being
419  * completed.
420  */
421 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
422 {
423         if (!acpi_ec_started(ec))
424                 return false;
425         acpi_ec_submit_request(ec);
426         return true;
427 }
428
429 static void acpi_ec_submit_query(struct acpi_ec *ec)
430 {
431         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
432                 ec_dbg_evt("Command(%s) submitted/blocked",
433                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
434                 ec->nr_pending_queries++;
435                 schedule_work(&ec->work);
436         }
437 }
438
439 static void acpi_ec_complete_query(struct acpi_ec *ec)
440 {
441         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
442                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
443                 ec_dbg_evt("Command(%s) unblocked",
444                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
445         }
446 }
447
448 static bool acpi_ec_guard_event(struct acpi_ec *ec)
449 {
450         bool guarded = true;
451         unsigned long flags;
452
453         spin_lock_irqsave(&ec->lock, flags);
454         /*
455          * If firmware SCI_EVT clearing timing is "event", we actually
456          * don't know when the SCI_EVT will be cleared by firmware after
457          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
458          * acceptable period.
459          *
460          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
461          * flagged, which means SCI_EVT check has just been performed.
462          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
463          * guarding should have already been performed (via
464          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
465          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
466          * ACPI_EC_COMMAND_POLL state immediately.
467          */
468         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
469             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
470             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
471             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
472                 guarded = false;
473         spin_unlock_irqrestore(&ec->lock, flags);
474         return guarded;
475 }
476
477 static int ec_transaction_polled(struct acpi_ec *ec)
478 {
479         unsigned long flags;
480         int ret = 0;
481
482         spin_lock_irqsave(&ec->lock, flags);
483         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
484                 ret = 1;
485         spin_unlock_irqrestore(&ec->lock, flags);
486         return ret;
487 }
488
489 static int ec_transaction_completed(struct acpi_ec *ec)
490 {
491         unsigned long flags;
492         int ret = 0;
493
494         spin_lock_irqsave(&ec->lock, flags);
495         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
496                 ret = 1;
497         spin_unlock_irqrestore(&ec->lock, flags);
498         return ret;
499 }
500
501 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
502 {
503         ec->curr->flags |= flag;
504         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
505                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
506                     flag == ACPI_EC_COMMAND_POLL)
507                         acpi_ec_complete_query(ec);
508                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
509                     flag == ACPI_EC_COMMAND_COMPLETE)
510                         acpi_ec_complete_query(ec);
511                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
512                     flag == ACPI_EC_COMMAND_COMPLETE)
513                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
514         }
515 }
516
517 static void advance_transaction(struct acpi_ec *ec)
518 {
519         struct transaction *t;
520         u8 status;
521         bool wakeup = false;
522
523         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
524                    smp_processor_id());
525         /*
526          * By always clearing STS before handling all indications, we can
527          * ensure a hardware STS 0->1 change after this clearing can always
528          * trigger a GPE interrupt.
529          */
530         acpi_ec_clear_gpe(ec);
531         status = acpi_ec_read_status(ec);
532         t = ec->curr;
533         /*
534          * Another IRQ or a guarded polling mode advancement is detected,
535          * the next QR_EC submission is then allowed.
536          */
537         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
538                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
539                     (!ec->nr_pending_queries ||
540                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
541                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
542                         acpi_ec_complete_query(ec);
543                 }
544         }
545         if (!t)
546                 goto err;
547         if (t->flags & ACPI_EC_COMMAND_POLL) {
548                 if (t->wlen > t->wi) {
549                         if ((status & ACPI_EC_FLAG_IBF) == 0)
550                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
551                         else
552                                 goto err;
553                 } else if (t->rlen > t->ri) {
554                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
555                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
556                                 if (t->rlen == t->ri) {
557                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
558                                         if (t->command == ACPI_EC_COMMAND_QUERY)
559                                                 ec_dbg_evt("Command(%s) completed by hardware",
560                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
561                                         wakeup = true;
562                                 }
563                         } else
564                                 goto err;
565                 } else if (t->wlen == t->wi &&
566                            (status & ACPI_EC_FLAG_IBF) == 0) {
567                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
568                         wakeup = true;
569                 }
570                 goto out;
571         } else {
572                 if (EC_FLAGS_QUERY_HANDSHAKE &&
573                     !(status & ACPI_EC_FLAG_SCI) &&
574                     (t->command == ACPI_EC_COMMAND_QUERY)) {
575                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
576                         t->rdata[t->ri++] = 0x00;
577                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
578                         ec_dbg_evt("Command(%s) completed by software",
579                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
580                         wakeup = true;
581                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
582                         acpi_ec_write_cmd(ec, t->command);
583                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
584                 } else
585                         goto err;
586                 goto out;
587         }
588 err:
589         /*
590          * If SCI bit is set, then don't think it's a false IRQ
591          * otherwise will take a not handled IRQ as a false one.
592          */
593         if (!(status & ACPI_EC_FLAG_SCI)) {
594                 if (in_interrupt() && t) {
595                         if (t->irq_count < ec_storm_threshold)
596                                 ++t->irq_count;
597                         /* Allow triggering on 0 threshold */
598                         if (t->irq_count == ec_storm_threshold)
599                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
600                 }
601         }
602 out:
603         if (status & ACPI_EC_FLAG_SCI)
604                 acpi_ec_submit_query(ec);
605         if (wakeup && in_interrupt())
606                 wake_up(&ec->wait);
607 }
608
609 static void start_transaction(struct acpi_ec *ec)
610 {
611         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
612         ec->curr->flags = 0;
613 }
614
615 static int ec_guard(struct acpi_ec *ec)
616 {
617         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
618         unsigned long timeout = ec->timestamp + guard;
619
620         /* Ensure guarding period before polling EC status */
621         do {
622                 if (ec_busy_polling) {
623                         /* Perform busy polling */
624                         if (ec_transaction_completed(ec))
625                                 return 0;
626                         udelay(jiffies_to_usecs(guard));
627                 } else {
628                         /*
629                          * Perform wait polling
630                          * 1. Wait the transaction to be completed by the
631                          *    GPE handler after the transaction enters
632                          *    ACPI_EC_COMMAND_POLL state.
633                          * 2. A special guarding logic is also required
634                          *    for event clearing mode "event" before the
635                          *    transaction enters ACPI_EC_COMMAND_POLL
636                          *    state.
637                          */
638                         if (!ec_transaction_polled(ec) &&
639                             !acpi_ec_guard_event(ec))
640                                 break;
641                         if (wait_event_timeout(ec->wait,
642                                                ec_transaction_completed(ec),
643                                                guard))
644                                 return 0;
645                 }
646         } while (time_before(jiffies, timeout));
647         return -ETIME;
648 }
649
650 static int ec_poll(struct acpi_ec *ec)
651 {
652         unsigned long flags;
653         int repeat = 5; /* number of command restarts */
654
655         while (repeat--) {
656                 unsigned long delay = jiffies +
657                         msecs_to_jiffies(ec_delay);
658                 do {
659                         if (!ec_guard(ec))
660                                 return 0;
661                         spin_lock_irqsave(&ec->lock, flags);
662                         advance_transaction(ec);
663                         spin_unlock_irqrestore(&ec->lock, flags);
664                 } while (time_before(jiffies, delay));
665                 pr_debug("controller reset, restart transaction\n");
666                 spin_lock_irqsave(&ec->lock, flags);
667                 start_transaction(ec);
668                 spin_unlock_irqrestore(&ec->lock, flags);
669         }
670         return -ETIME;
671 }
672
673 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
674                                         struct transaction *t)
675 {
676         unsigned long tmp;
677         int ret = 0;
678
679         /* start transaction */
680         spin_lock_irqsave(&ec->lock, tmp);
681         /* Enable GPE for command processing (IBF=0/OBF=1) */
682         if (!acpi_ec_submit_flushable_request(ec)) {
683                 ret = -EINVAL;
684                 goto unlock;
685         }
686         ec_dbg_ref(ec, "Increase command");
687         /* following two actions should be kept atomic */
688         ec->curr = t;
689         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
690         start_transaction(ec);
691         spin_unlock_irqrestore(&ec->lock, tmp);
692
693         ret = ec_poll(ec);
694
695         spin_lock_irqsave(&ec->lock, tmp);
696         if (t->irq_count == ec_storm_threshold)
697                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
698         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
699         ec->curr = NULL;
700         /* Disable GPE for command processing (IBF=0/OBF=1) */
701         acpi_ec_complete_request(ec);
702         ec_dbg_ref(ec, "Decrease command");
703 unlock:
704         spin_unlock_irqrestore(&ec->lock, tmp);
705         return ret;
706 }
707
708 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
709 {
710         int status;
711         u32 glk;
712
713         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
714                 return -EINVAL;
715         if (t->rdata)
716                 memset(t->rdata, 0, t->rlen);
717
718         mutex_lock(&ec->mutex);
719         if (ec->global_lock) {
720                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
721                 if (ACPI_FAILURE(status)) {
722                         status = -ENODEV;
723                         goto unlock;
724                 }
725         }
726
727         status = acpi_ec_transaction_unlocked(ec, t);
728
729         if (ec->global_lock)
730                 acpi_release_global_lock(glk);
731 unlock:
732         mutex_unlock(&ec->mutex);
733         return status;
734 }
735
736 static int acpi_ec_burst_enable(struct acpi_ec *ec)
737 {
738         u8 d;
739         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
740                                 .wdata = NULL, .rdata = &d,
741                                 .wlen = 0, .rlen = 1};
742
743         return acpi_ec_transaction(ec, &t);
744 }
745
746 static int acpi_ec_burst_disable(struct acpi_ec *ec)
747 {
748         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
749                                 .wdata = NULL, .rdata = NULL,
750                                 .wlen = 0, .rlen = 0};
751
752         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
753                                 acpi_ec_transaction(ec, &t) : 0;
754 }
755
756 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
757 {
758         int result;
759         u8 d;
760         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
761                                 .wdata = &address, .rdata = &d,
762                                 .wlen = 1, .rlen = 1};
763
764         result = acpi_ec_transaction(ec, &t);
765         *data = d;
766         return result;
767 }
768
769 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
770 {
771         u8 wdata[2] = { address, data };
772         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
773                                 .wdata = wdata, .rdata = NULL,
774                                 .wlen = 2, .rlen = 0};
775
776         return acpi_ec_transaction(ec, &t);
777 }
778
779 int ec_read(u8 addr, u8 *val)
780 {
781         int err;
782         u8 temp_data;
783
784         if (!first_ec)
785                 return -ENODEV;
786
787         err = acpi_ec_read(first_ec, addr, &temp_data);
788
789         if (!err) {
790                 *val = temp_data;
791                 return 0;
792         }
793         return err;
794 }
795 EXPORT_SYMBOL(ec_read);
796
797 int ec_write(u8 addr, u8 val)
798 {
799         int err;
800
801         if (!first_ec)
802                 return -ENODEV;
803
804         err = acpi_ec_write(first_ec, addr, val);
805
806         return err;
807 }
808 EXPORT_SYMBOL(ec_write);
809
810 int ec_transaction(u8 command,
811                    const u8 *wdata, unsigned wdata_len,
812                    u8 *rdata, unsigned rdata_len)
813 {
814         struct transaction t = {.command = command,
815                                 .wdata = wdata, .rdata = rdata,
816                                 .wlen = wdata_len, .rlen = rdata_len};
817
818         if (!first_ec)
819                 return -ENODEV;
820
821         return acpi_ec_transaction(first_ec, &t);
822 }
823 EXPORT_SYMBOL(ec_transaction);
824
825 /* Get the handle to the EC device */
826 acpi_handle ec_get_handle(void)
827 {
828         if (!first_ec)
829                 return NULL;
830         return first_ec->handle;
831 }
832 EXPORT_SYMBOL(ec_get_handle);
833
834 /*
835  * Process _Q events that might have accumulated in the EC.
836  * Run with locked ec mutex.
837  */
838 static void acpi_ec_clear(struct acpi_ec *ec)
839 {
840         int i, status;
841         u8 value = 0;
842
843         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
844                 status = acpi_ec_query(ec, &value);
845                 if (status || !value)
846                         break;
847         }
848
849         if (unlikely(i == ACPI_EC_CLEAR_MAX))
850                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
851         else
852                 pr_info("%d stale EC events cleared\n", i);
853 }
854
855 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
856 {
857         unsigned long flags;
858
859         spin_lock_irqsave(&ec->lock, flags);
860         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
861                 ec_dbg_drv("Starting EC");
862                 /* Enable GPE for event processing (SCI_EVT=1) */
863                 if (!resuming) {
864                         acpi_ec_submit_request(ec);
865                         ec_dbg_ref(ec, "Increase driver");
866                 }
867                 ec_log_drv("EC started");
868         }
869         spin_unlock_irqrestore(&ec->lock, flags);
870 }
871
872 static bool acpi_ec_stopped(struct acpi_ec *ec)
873 {
874         unsigned long flags;
875         bool flushed;
876
877         spin_lock_irqsave(&ec->lock, flags);
878         flushed = acpi_ec_flushed(ec);
879         spin_unlock_irqrestore(&ec->lock, flags);
880         return flushed;
881 }
882
883 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
884 {
885         unsigned long flags;
886
887         spin_lock_irqsave(&ec->lock, flags);
888         if (acpi_ec_started(ec)) {
889                 ec_dbg_drv("Stopping EC");
890                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
891                 spin_unlock_irqrestore(&ec->lock, flags);
892                 wait_event(ec->wait, acpi_ec_stopped(ec));
893                 spin_lock_irqsave(&ec->lock, flags);
894                 /* Disable GPE for event processing (SCI_EVT=1) */
895                 if (!suspending) {
896                         acpi_ec_complete_request(ec);
897                         ec_dbg_ref(ec, "Decrease driver");
898                 }
899                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
900                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
901                 ec_log_drv("EC stopped");
902         }
903         spin_unlock_irqrestore(&ec->lock, flags);
904 }
905
906 void acpi_ec_block_transactions(void)
907 {
908         struct acpi_ec *ec = first_ec;
909
910         if (!ec)
911                 return;
912
913         mutex_lock(&ec->mutex);
914         /* Prevent transactions from being carried out */
915         acpi_ec_stop(ec, true);
916         mutex_unlock(&ec->mutex);
917 }
918
919 void acpi_ec_unblock_transactions(void)
920 {
921         struct acpi_ec *ec = first_ec;
922
923         if (!ec)
924                 return;
925
926         /* Allow transactions to be carried out again */
927         acpi_ec_start(ec, true);
928
929         if (EC_FLAGS_CLEAR_ON_RESUME)
930                 acpi_ec_clear(ec);
931 }
932
933 void acpi_ec_unblock_transactions_early(void)
934 {
935         /*
936          * Allow transactions to happen again (this function is called from
937          * atomic context during wakeup, so we don't need to acquire the mutex).
938          */
939         if (first_ec)
940                 acpi_ec_start(first_ec, true);
941 }
942
943 /* --------------------------------------------------------------------------
944                                 Event Management
945    -------------------------------------------------------------------------- */
946 static struct acpi_ec_query_handler *
947 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
948 {
949         struct acpi_ec_query_handler *handler;
950
951         mutex_lock(&ec->mutex);
952         list_for_each_entry(handler, &ec->list, node) {
953                 if (value == handler->query_bit) {
954                         kref_get(&handler->kref);
955                         mutex_unlock(&ec->mutex);
956                         return handler;
957                 }
958         }
959         mutex_unlock(&ec->mutex);
960         return NULL;
961 }
962
963 static void acpi_ec_query_handler_release(struct kref *kref)
964 {
965         struct acpi_ec_query_handler *handler =
966                 container_of(kref, struct acpi_ec_query_handler, kref);
967
968         kfree(handler);
969 }
970
971 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
972 {
973         kref_put(&handler->kref, acpi_ec_query_handler_release);
974 }
975
976 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
977                               acpi_handle handle, acpi_ec_query_func func,
978                               void *data)
979 {
980         struct acpi_ec_query_handler *handler =
981             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
982
983         if (!handler)
984                 return -ENOMEM;
985
986         handler->query_bit = query_bit;
987         handler->handle = handle;
988         handler->func = func;
989         handler->data = data;
990         mutex_lock(&ec->mutex);
991         kref_init(&handler->kref);
992         list_add(&handler->node, &ec->list);
993         mutex_unlock(&ec->mutex);
994         return 0;
995 }
996 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
997
998 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
999                                           bool remove_all, u8 query_bit)
1000 {
1001         struct acpi_ec_query_handler *handler, *tmp;
1002         LIST_HEAD(free_list);
1003
1004         mutex_lock(&ec->mutex);
1005         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1006                 if (remove_all || query_bit == handler->query_bit) {
1007                         list_del_init(&handler->node);
1008                         list_add(&handler->node, &free_list);
1009                 }
1010         }
1011         mutex_unlock(&ec->mutex);
1012         list_for_each_entry_safe(handler, tmp, &free_list, node)
1013                 acpi_ec_put_query_handler(handler);
1014 }
1015
1016 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1017 {
1018         acpi_ec_remove_query_handlers(ec, false, query_bit);
1019 }
1020 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1021
1022 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1023 {
1024         struct acpi_ec_query *q;
1025         struct transaction *t;
1026
1027         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1028         if (!q)
1029                 return NULL;
1030         INIT_WORK(&q->work, acpi_ec_event_processor);
1031         t = &q->transaction;
1032         t->command = ACPI_EC_COMMAND_QUERY;
1033         t->rdata = pval;
1034         t->rlen = 1;
1035         return q;
1036 }
1037
1038 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1039 {
1040         if (q) {
1041                 if (q->handler)
1042                         acpi_ec_put_query_handler(q->handler);
1043                 kfree(q);
1044         }
1045 }
1046
1047 static void acpi_ec_event_processor(struct work_struct *work)
1048 {
1049         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1050         struct acpi_ec_query_handler *handler = q->handler;
1051
1052         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1053         if (handler->func)
1054                 handler->func(handler->data);
1055         else if (handler->handle)
1056                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1057         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1058         acpi_ec_delete_query(q);
1059 }
1060
1061 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1062 {
1063         u8 value = 0;
1064         int result;
1065         struct acpi_ec_query *q;
1066
1067         q = acpi_ec_create_query(&value);
1068         if (!q)
1069                 return -ENOMEM;
1070
1071         /*
1072          * Query the EC to find out which _Qxx method we need to evaluate.
1073          * Note that successful completion of the query causes the ACPI_EC_SCI
1074          * bit to be cleared (and thus clearing the interrupt source).
1075          */
1076         result = acpi_ec_transaction(ec, &q->transaction);
1077         if (!value)
1078                 result = -ENODATA;
1079         if (result)
1080                 goto err_exit;
1081
1082         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1083         if (!q->handler) {
1084                 result = -ENODATA;
1085                 goto err_exit;
1086         }
1087
1088         /*
1089          * It is reported that _Qxx are evaluated in a parallel way on
1090          * Windows:
1091          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1092          *
1093          * Put this log entry before schedule_work() in order to make
1094          * it appearing before any other log entries occurred during the
1095          * work queue execution.
1096          */
1097         ec_dbg_evt("Query(0x%02x) scheduled", value);
1098         if (!queue_work(ec_query_wq, &q->work)) {
1099                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1100                 result = -EBUSY;
1101         }
1102
1103 err_exit:
1104         if (result)
1105                 acpi_ec_delete_query(q);
1106         if (data)
1107                 *data = value;
1108         return result;
1109 }
1110
1111 static void acpi_ec_check_event(struct acpi_ec *ec)
1112 {
1113         unsigned long flags;
1114
1115         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1116                 if (ec_guard(ec)) {
1117                         spin_lock_irqsave(&ec->lock, flags);
1118                         /*
1119                          * Take care of the SCI_EVT unless no one else is
1120                          * taking care of it.
1121                          */
1122                         if (!ec->curr)
1123                                 advance_transaction(ec);
1124                         spin_unlock_irqrestore(&ec->lock, flags);
1125                 }
1126         }
1127 }
1128
1129 static void acpi_ec_event_handler(struct work_struct *work)
1130 {
1131         unsigned long flags;
1132         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1133
1134         ec_dbg_evt("Event started");
1135
1136         spin_lock_irqsave(&ec->lock, flags);
1137         while (ec->nr_pending_queries) {
1138                 spin_unlock_irqrestore(&ec->lock, flags);
1139                 (void)acpi_ec_query(ec, NULL);
1140                 spin_lock_irqsave(&ec->lock, flags);
1141                 ec->nr_pending_queries--;
1142                 /*
1143                  * Before exit, make sure that this work item can be
1144                  * scheduled again. There might be QR_EC failures, leaving
1145                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1146                  * item from being scheduled again.
1147                  */
1148                 if (!ec->nr_pending_queries) {
1149                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1150                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1151                                 acpi_ec_complete_query(ec);
1152                 }
1153         }
1154         spin_unlock_irqrestore(&ec->lock, flags);
1155
1156         ec_dbg_evt("Event stopped");
1157
1158         acpi_ec_check_event(ec);
1159 }
1160
1161 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1162         u32 gpe_number, void *data)
1163 {
1164         unsigned long flags;
1165         struct acpi_ec *ec = data;
1166
1167         spin_lock_irqsave(&ec->lock, flags);
1168         advance_transaction(ec);
1169         spin_unlock_irqrestore(&ec->lock, flags);
1170         return ACPI_INTERRUPT_HANDLED;
1171 }
1172
1173 /* --------------------------------------------------------------------------
1174  *                           Address Space Management
1175  * -------------------------------------------------------------------------- */
1176
1177 static acpi_status
1178 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1179                       u32 bits, u64 *value64,
1180                       void *handler_context, void *region_context)
1181 {
1182         struct acpi_ec *ec = handler_context;
1183         int result = 0, i, bytes = bits / 8;
1184         u8 *value = (u8 *)value64;
1185
1186         if ((address > 0xFF) || !value || !handler_context)
1187                 return AE_BAD_PARAMETER;
1188
1189         if (function != ACPI_READ && function != ACPI_WRITE)
1190                 return AE_BAD_PARAMETER;
1191
1192         if (ec_busy_polling || bits > 8)
1193                 acpi_ec_burst_enable(ec);
1194
1195         for (i = 0; i < bytes; ++i, ++address, ++value)
1196                 result = (function == ACPI_READ) ?
1197                         acpi_ec_read(ec, address, value) :
1198                         acpi_ec_write(ec, address, *value);
1199
1200         if (ec_busy_polling || bits > 8)
1201                 acpi_ec_burst_disable(ec);
1202
1203         switch (result) {
1204         case -EINVAL:
1205                 return AE_BAD_PARAMETER;
1206         case -ENODEV:
1207                 return AE_NOT_FOUND;
1208         case -ETIME:
1209                 return AE_TIME;
1210         default:
1211                 return AE_OK;
1212         }
1213 }
1214
1215 /* --------------------------------------------------------------------------
1216  *                             Driver Interface
1217  * -------------------------------------------------------------------------- */
1218
1219 static acpi_status
1220 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1221
1222 static struct acpi_ec *make_acpi_ec(void)
1223 {
1224         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1225
1226         if (!ec)
1227                 return NULL;
1228         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1229         mutex_init(&ec->mutex);
1230         init_waitqueue_head(&ec->wait);
1231         INIT_LIST_HEAD(&ec->list);
1232         spin_lock_init(&ec->lock);
1233         INIT_WORK(&ec->work, acpi_ec_event_handler);
1234         ec->timestamp = jiffies;
1235         return ec;
1236 }
1237
1238 static acpi_status
1239 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1240                                void *context, void **return_value)
1241 {
1242         char node_name[5];
1243         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1244         struct acpi_ec *ec = context;
1245         int value = 0;
1246         acpi_status status;
1247
1248         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1249
1250         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1251                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1252         return AE_OK;
1253 }
1254
1255 static acpi_status
1256 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1257 {
1258         acpi_status status;
1259         unsigned long long tmp = 0;
1260         struct acpi_ec *ec = context;
1261
1262         /* clear addr values, ec_parse_io_ports depend on it */
1263         ec->command_addr = ec->data_addr = 0;
1264
1265         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1266                                      ec_parse_io_ports, ec);
1267         if (ACPI_FAILURE(status))
1268                 return status;
1269
1270         /* Get GPE bit assignment (EC events). */
1271         /* TODO: Add support for _GPE returning a package */
1272         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1273         if (ACPI_FAILURE(status))
1274                 return status;
1275         ec->gpe = tmp;
1276         /* Use the global lock for all EC transactions? */
1277         tmp = 0;
1278         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1279         ec->global_lock = tmp;
1280         ec->handle = handle;
1281         return AE_CTRL_TERMINATE;
1282 }
1283
1284 static int ec_install_handlers(struct acpi_ec *ec)
1285 {
1286         acpi_status status;
1287
1288         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1289                 return 0;
1290         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1291                                   ACPI_GPE_EDGE_TRIGGERED,
1292                                   &acpi_ec_gpe_handler, ec);
1293         if (ACPI_FAILURE(status))
1294                 return -ENODEV;
1295
1296         acpi_ec_start(ec, false);
1297         status = acpi_install_address_space_handler(ec->handle,
1298                                                     ACPI_ADR_SPACE_EC,
1299                                                     &acpi_ec_space_handler,
1300                                                     NULL, ec);
1301         if (ACPI_FAILURE(status)) {
1302                 if (status == AE_NOT_FOUND) {
1303                         /*
1304                          * Maybe OS fails in evaluating the _REG object.
1305                          * The AE_NOT_FOUND error will be ignored and OS
1306                          * continue to initialize EC.
1307                          */
1308                         pr_err("Fail in evaluating the _REG object"
1309                                 " of EC device. Broken bios is suspected.\n");
1310                 } else {
1311                         acpi_ec_stop(ec, false);
1312                         acpi_remove_gpe_handler(NULL, ec->gpe,
1313                                 &acpi_ec_gpe_handler);
1314                         return -ENODEV;
1315                 }
1316         }
1317
1318         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1319         return 0;
1320 }
1321
1322 static void ec_remove_handlers(struct acpi_ec *ec)
1323 {
1324         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1325                 return;
1326         acpi_ec_stop(ec, false);
1327         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1328                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1329                 pr_err("failed to remove space handler\n");
1330         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1331                                 &acpi_ec_gpe_handler)))
1332                 pr_err("failed to remove gpe handler\n");
1333         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1334 }
1335
1336 static int acpi_ec_add(struct acpi_device *device)
1337 {
1338         struct acpi_ec *ec = NULL;
1339         int ret;
1340
1341         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1342         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1343
1344         /* Check for boot EC */
1345         if (boot_ec &&
1346             (boot_ec->handle == device->handle ||
1347              boot_ec->handle == ACPI_ROOT_OBJECT)) {
1348                 ec = boot_ec;
1349                 boot_ec = NULL;
1350         } else {
1351                 ec = make_acpi_ec();
1352                 if (!ec)
1353                         return -ENOMEM;
1354         }
1355         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1356                 AE_CTRL_TERMINATE) {
1357                         kfree(ec);
1358                         return -EINVAL;
1359         }
1360
1361         /* Find and register all query methods */
1362         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1363                             acpi_ec_register_query_methods, NULL, ec, NULL);
1364
1365         if (!first_ec)
1366                 first_ec = ec;
1367         device->driver_data = ec;
1368
1369         ret = !!request_region(ec->data_addr, 1, "EC data");
1370         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1371         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1372         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1373
1374         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1375                           ec->gpe, ec->command_addr, ec->data_addr);
1376
1377         ret = ec_install_handlers(ec);
1378
1379         /* Reprobe devices depending on the EC */
1380         acpi_walk_dep_device_list(ec->handle);
1381
1382         /* EC is fully operational, allow queries */
1383         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1384
1385         /* Clear stale _Q events if hardware might require that */
1386         if (EC_FLAGS_CLEAR_ON_RESUME)
1387                 acpi_ec_clear(ec);
1388         return ret;
1389 }
1390
1391 static int acpi_ec_remove(struct acpi_device *device)
1392 {
1393         struct acpi_ec *ec;
1394
1395         if (!device)
1396                 return -EINVAL;
1397
1398         ec = acpi_driver_data(device);
1399         ec_remove_handlers(ec);
1400         acpi_ec_remove_query_handlers(ec, true, 0);
1401         release_region(ec->data_addr, 1);
1402         release_region(ec->command_addr, 1);
1403         device->driver_data = NULL;
1404         if (ec == first_ec)
1405                 first_ec = NULL;
1406         kfree(ec);
1407         return 0;
1408 }
1409
1410 static acpi_status
1411 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1412 {
1413         struct acpi_ec *ec = context;
1414
1415         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1416                 return AE_OK;
1417
1418         /*
1419          * The first address region returned is the data port, and
1420          * the second address region returned is the status/command
1421          * port.
1422          */
1423         if (ec->data_addr == 0)
1424                 ec->data_addr = resource->data.io.minimum;
1425         else if (ec->command_addr == 0)
1426                 ec->command_addr = resource->data.io.minimum;
1427         else
1428                 return AE_CTRL_TERMINATE;
1429
1430         return AE_OK;
1431 }
1432
1433 int __init acpi_boot_ec_enable(void)
1434 {
1435         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1436                 return 0;
1437         if (!ec_install_handlers(boot_ec)) {
1438                 first_ec = boot_ec;
1439                 return 0;
1440         }
1441         return -EFAULT;
1442 }
1443
1444 static const struct acpi_device_id ec_device_ids[] = {
1445         {"PNP0C09", 0},
1446         {"", 0},
1447 };
1448
1449 /* Some BIOS do not survive early DSDT scan, skip it */
1450 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1451 {
1452         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1453         return 0;
1454 }
1455
1456 /* ASUStek often supplies us with broken ECDT, validate it */
1457 static int ec_validate_ecdt(const struct dmi_system_id *id)
1458 {
1459         EC_FLAGS_VALIDATE_ECDT = 1;
1460         return 0;
1461 }
1462
1463 #if 0
1464 /*
1465  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1466  * set, for which case, we complete the QR_EC without issuing it to the
1467  * firmware.
1468  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1469  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1470  */
1471 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1472 {
1473         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1474         EC_FLAGS_QUERY_HANDSHAKE = 1;
1475         return 0;
1476 }
1477 #endif
1478
1479 /*
1480  * On some hardware it is necessary to clear events accumulated by the EC during
1481  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1482  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1483  *
1484  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1485  *
1486  * Ideally, the EC should also be instructed NOT to accumulate events during
1487  * sleep (which Windows seems to do somehow), but the interface to control this
1488  * behaviour is not known at this time.
1489  *
1490  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1491  * however it is very likely that other Samsung models are affected.
1492  *
1493  * On systems which don't accumulate _Q events during sleep, this extra check
1494  * should be harmless.
1495  */
1496 static int ec_clear_on_resume(const struct dmi_system_id *id)
1497 {
1498         pr_debug("Detected system needing EC poll on resume.\n");
1499         EC_FLAGS_CLEAR_ON_RESUME = 1;
1500         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1501         return 0;
1502 }
1503
1504 static struct dmi_system_id ec_dmi_table[] __initdata = {
1505         {
1506         ec_skip_dsdt_scan, "Compal JFL92", {
1507         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1508         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1509         {
1510         ec_validate_ecdt, "MSI MS-171F", {
1511         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1512         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1513         {
1514         ec_validate_ecdt, "ASUS hardware", {
1515         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1516         {
1517         ec_validate_ecdt, "ASUS hardware", {
1518         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1519         {
1520         ec_skip_dsdt_scan, "HP Folio 13", {
1521         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1522         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1523         {
1524         ec_validate_ecdt, "ASUS hardware", {
1525         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1526         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1527         {
1528         ec_clear_on_resume, "Samsung hardware", {
1529         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1530         {},
1531 };
1532
1533 int __init acpi_ec_ecdt_probe(void)
1534 {
1535         acpi_status status;
1536         struct acpi_ec *saved_ec = NULL;
1537         struct acpi_table_ecdt *ecdt_ptr;
1538
1539         boot_ec = make_acpi_ec();
1540         if (!boot_ec)
1541                 return -ENOMEM;
1542         /*
1543          * Generate a boot ec context
1544          */
1545         dmi_check_system(ec_dmi_table);
1546         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1547                                 (struct acpi_table_header **)&ecdt_ptr);
1548         if (ACPI_SUCCESS(status)) {
1549                 pr_info("EC description table is found, configuring boot EC\n");
1550                 boot_ec->command_addr = ecdt_ptr->control.address;
1551                 boot_ec->data_addr = ecdt_ptr->data.address;
1552                 boot_ec->gpe = ecdt_ptr->gpe;
1553                 boot_ec->handle = ACPI_ROOT_OBJECT;
1554                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1555                                 &boot_ec->handle);
1556                 /* Don't trust ECDT, which comes from ASUSTek */
1557                 if (!EC_FLAGS_VALIDATE_ECDT)
1558                         goto install;
1559                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1560                 if (!saved_ec)
1561                         return -ENOMEM;
1562         /* fall through */
1563         }
1564
1565         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1566                 kfree(saved_ec);
1567                 return -ENODEV;
1568         }
1569
1570         /* This workaround is needed only on some broken machines,
1571          * which require early EC, but fail to provide ECDT */
1572         pr_debug("Look up EC in DSDT\n");
1573         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1574                                         boot_ec, NULL);
1575         /* Check that acpi_get_devices actually find something */
1576         if (ACPI_FAILURE(status) || !boot_ec->handle)
1577                 goto error;
1578         if (saved_ec) {
1579                 /* try to find good ECDT from ASUSTek */
1580                 if (saved_ec->command_addr != boot_ec->command_addr ||
1581                     saved_ec->data_addr != boot_ec->data_addr ||
1582                     saved_ec->gpe != boot_ec->gpe ||
1583                     saved_ec->handle != boot_ec->handle)
1584                         pr_info("ASUSTek keeps feeding us with broken "
1585                         "ECDT tables, which are very hard to workaround. "
1586                         "Trying to use DSDT EC info instead. Please send "
1587                         "output of acpidump to linux-acpi@vger.kernel.org\n");
1588                 kfree(saved_ec);
1589                 saved_ec = NULL;
1590         } else {
1591                 /* We really need to limit this workaround, the only ASUS,
1592                 * which needs it, has fake EC._INI method, so use it as flag.
1593                 * Keep boot_ec struct as it will be needed soon.
1594                 */
1595                 if (!dmi_name_in_vendors("ASUS") ||
1596                     !acpi_has_method(boot_ec->handle, "_INI"))
1597                         return -ENODEV;
1598         }
1599 install:
1600         if (!ec_install_handlers(boot_ec)) {
1601                 first_ec = boot_ec;
1602                 return 0;
1603         }
1604 error:
1605         kfree(boot_ec);
1606         kfree(saved_ec);
1607         boot_ec = NULL;
1608         return -ENODEV;
1609 }
1610
1611 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1612 {
1613         int result = 0;
1614
1615         if (!strncmp(val, "status", sizeof("status") - 1)) {
1616                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1617                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1618         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1619                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1620                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1621         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1622                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1623                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1624         } else
1625                 result = -EINVAL;
1626         return result;
1627 }
1628
1629 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1630 {
1631         switch (ec_event_clearing) {
1632         case ACPI_EC_EVT_TIMING_STATUS:
1633                 return sprintf(buffer, "status");
1634         case ACPI_EC_EVT_TIMING_QUERY:
1635                 return sprintf(buffer, "query");
1636         case ACPI_EC_EVT_TIMING_EVENT:
1637                 return sprintf(buffer, "event");
1638         default:
1639                 return sprintf(buffer, "invalid");
1640         }
1641         return 0;
1642 }
1643
1644 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1645                   NULL, 0644);
1646 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1647
1648 static struct acpi_driver acpi_ec_driver = {
1649         .name = "ec",
1650         .class = ACPI_EC_CLASS,
1651         .ids = ec_device_ids,
1652         .ops = {
1653                 .add = acpi_ec_add,
1654                 .remove = acpi_ec_remove,
1655                 },
1656 };
1657
1658 static inline int acpi_ec_query_init(void)
1659 {
1660         if (!ec_query_wq) {
1661                 ec_query_wq = alloc_workqueue("kec_query", 0,
1662                                               ec_max_queries);
1663                 if (!ec_query_wq)
1664                         return -ENODEV;
1665         }
1666         return 0;
1667 }
1668
1669 static inline void acpi_ec_query_exit(void)
1670 {
1671         if (ec_query_wq) {
1672                 destroy_workqueue(ec_query_wq);
1673                 ec_query_wq = NULL;
1674         }
1675 }
1676
1677 int __init acpi_ec_init(void)
1678 {
1679         int result;
1680
1681         /* register workqueue for _Qxx evaluations */
1682         result = acpi_ec_query_init();
1683         if (result)
1684                 goto err_exit;
1685         /* Now register the driver for the EC */
1686         result = acpi_bus_register_driver(&acpi_ec_driver);
1687         if (result)
1688                 goto err_exit;
1689
1690 err_exit:
1691         if (result)
1692                 acpi_ec_query_exit();
1693         return result;
1694 }
1695
1696 /* EC driver currently not unloadable */
1697 #if 0
1698 static void __exit acpi_ec_exit(void)
1699 {
1700
1701         acpi_bus_unregister_driver(&acpi_ec_driver);
1702         acpi_ec_query_exit();
1703 }
1704 #endif  /* 0 */