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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 
105 enum {
106         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
107         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
108         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
109                                          * OpReg are installed */
110         EC_FLAGS_STARTED,               /* Driver is started */
111         EC_FLAGS_STOPPED,               /* Driver is stopped */
112         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
113                                          * current command processing */
114 };
115 
116 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
117 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
118 
119 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
120 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
121 module_param(ec_delay, uint, 0644);
122 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
123 
124 static bool ec_busy_polling __read_mostly;
125 module_param(ec_busy_polling, bool, 0644);
126 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
127 
128 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
129 module_param(ec_polling_guard, uint, 0644);
130 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
131 
132 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
133 
134 /*
135  * If the number of false interrupts per one transaction exceeds
136  * this threshold, will think there is a GPE storm happened and
137  * will disable the GPE for normal transaction.
138  */
139 static unsigned int ec_storm_threshold  __read_mostly = 8;
140 module_param(ec_storm_threshold, uint, 0644);
141 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
142 
143 struct acpi_ec_query_handler {
144         struct list_head node;
145         acpi_ec_query_func func;
146         acpi_handle handle;
147         void *data;
148         u8 query_bit;
149         struct kref kref;
150 };
151 
152 struct transaction {
153         const u8 *wdata;
154         u8 *rdata;
155         unsigned short irq_count;
156         u8 command;
157         u8 wi;
158         u8 ri;
159         u8 wlen;
160         u8 rlen;
161         u8 flags;
162 };
163 
164 struct acpi_ec_query {
165         struct transaction transaction;
166         struct work_struct work;
167         struct acpi_ec_query_handler *handler;
168 };
169 
170 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
171 static void advance_transaction(struct acpi_ec *ec);
172 static void acpi_ec_event_handler(struct work_struct *work);
173 static void acpi_ec_event_processor(struct work_struct *work);
174 
175 struct acpi_ec *boot_ec, *first_ec;
176 EXPORT_SYMBOL(first_ec);
177 
178 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
179 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
180 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
181 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
182 
183 /* --------------------------------------------------------------------------
184  *                           Logging/Debugging
185  * -------------------------------------------------------------------------- */
186 
187 /*
188  * Splitters used by the developers to track the boundary of the EC
189  * handling processes.
190  */
191 #ifdef DEBUG
192 #define EC_DBG_SEP      " "
193 #define EC_DBG_DRV      "+++++"
194 #define EC_DBG_STM      "====="
195 #define EC_DBG_REQ      "*****"
196 #define EC_DBG_EVT      "#####"
197 #else
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 #endif
204 
205 #define ec_log_raw(fmt, ...) \
206         pr_info(fmt "\n", ##__VA_ARGS__)
207 #define ec_dbg_raw(fmt, ...) \
208         pr_debug(fmt "\n", ##__VA_ARGS__)
209 #define ec_log(filter, fmt, ...) \
210         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
211 #define ec_dbg(filter, fmt, ...) \
212         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
213 
214 #define ec_log_drv(fmt, ...) \
215         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
216 #define ec_dbg_drv(fmt, ...) \
217         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
218 #define ec_dbg_stm(fmt, ...) \
219         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
220 #define ec_dbg_req(fmt, ...) \
221         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
222 #define ec_dbg_evt(fmt, ...) \
223         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
224 #define ec_dbg_ref(ec, fmt, ...) \
225         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
226 
227 /* --------------------------------------------------------------------------
228  *                           Device Flags
229  * -------------------------------------------------------------------------- */
230 
231 static bool acpi_ec_started(struct acpi_ec *ec)
232 {
233         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
234                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
235 }
236 
237 static bool acpi_ec_flushed(struct acpi_ec *ec)
238 {
239         return ec->reference_count == 1;
240 }
241 
242 /* --------------------------------------------------------------------------
243  *                           EC Registers
244  * -------------------------------------------------------------------------- */
245 
246 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
247 {
248         u8 x = inb(ec->command_addr);
249 
250         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
251                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
252                    x,
253                    !!(x & ACPI_EC_FLAG_SCI),
254                    !!(x & ACPI_EC_FLAG_BURST),
255                    !!(x & ACPI_EC_FLAG_CMD),
256                    !!(x & ACPI_EC_FLAG_IBF),
257                    !!(x & ACPI_EC_FLAG_OBF));
258         return x;
259 }
260 
261 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
262 {
263         u8 x = inb(ec->data_addr);
264 
265         ec->timestamp = jiffies;
266         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
267         return x;
268 }
269 
270 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
271 {
272         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
273         outb(command, ec->command_addr);
274         ec->timestamp = jiffies;
275 }
276 
277 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
278 {
279         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
280         outb(data, ec->data_addr);
281         ec->timestamp = jiffies;
282 }
283 
284 #ifdef DEBUG
285 static const char *acpi_ec_cmd_string(u8 cmd)
286 {
287         switch (cmd) {
288         case 0x80:
289                 return "RD_EC";
290         case 0x81:
291                 return "WR_EC";
292         case 0x82:
293                 return "BE_EC";
294         case 0x83:
295                 return "BD_EC";
296         case 0x84:
297                 return "QR_EC";
298         }
299         return "UNKNOWN";
300 }
301 #else
302 #define acpi_ec_cmd_string(cmd)         "UNDEF"
303 #endif
304 
305 /* --------------------------------------------------------------------------
306  *                           GPE Registers
307  * -------------------------------------------------------------------------- */
308 
309 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
310 {
311         acpi_event_status gpe_status = 0;
312 
313         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
314         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
315 }
316 
317 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
318 {
319         if (open)
320                 acpi_enable_gpe(NULL, ec->gpe);
321         else {
322                 BUG_ON(ec->reference_count < 1);
323                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
324         }
325         if (acpi_ec_is_gpe_raised(ec)) {
326                 /*
327                  * On some platforms, EN=1 writes cannot trigger GPE. So
328                  * software need to manually trigger a pseudo GPE event on
329                  * EN=1 writes.
330                  */
331                 ec_dbg_raw("Polling quirk");
332                 advance_transaction(ec);
333         }
334 }
335 
336 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
337 {
338         if (close)
339                 acpi_disable_gpe(NULL, ec->gpe);
340         else {
341                 BUG_ON(ec->reference_count < 1);
342                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
343         }
344 }
345 
346 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
347 {
348         /*
349          * GPE STS is a W1C register, which means:
350          * 1. Software can clear it without worrying about clearing other
351          *    GPEs' STS bits when the hardware sets them in parallel.
352          * 2. As long as software can ensure only clearing it when it is
353          *    set, hardware won't set it in parallel.
354          * So software can clear GPE in any contexts.
355          * Warning: do not move the check into advance_transaction() as the
356          * EC commands will be sent without GPE raised.
357          */
358         if (!acpi_ec_is_gpe_raised(ec))
359                 return;
360         acpi_clear_gpe(NULL, ec->gpe);
361 }
362 
363 /* --------------------------------------------------------------------------
364  *                           Transaction Management
365  * -------------------------------------------------------------------------- */
366 
367 static void acpi_ec_submit_request(struct acpi_ec *ec)
368 {
369         ec->reference_count++;
370         if (ec->reference_count == 1)
371                 acpi_ec_enable_gpe(ec, true);
372 }
373 
374 static void acpi_ec_complete_request(struct acpi_ec *ec)
375 {
376         bool flushed = false;
377 
378         ec->reference_count--;
379         if (ec->reference_count == 0)
380                 acpi_ec_disable_gpe(ec, true);
381         flushed = acpi_ec_flushed(ec);
382         if (flushed)
383                 wake_up(&ec->wait);
384 }
385 
386 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
387 {
388         if (!test_bit(flag, &ec->flags)) {
389                 acpi_ec_disable_gpe(ec, false);
390                 ec_dbg_drv("Polling enabled");
391                 set_bit(flag, &ec->flags);
392         }
393 }
394 
395 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
396 {
397         if (test_bit(flag, &ec->flags)) {
398                 clear_bit(flag, &ec->flags);
399                 acpi_ec_enable_gpe(ec, false);
400                 ec_dbg_drv("Polling disabled");
401         }
402 }
403 
404 /*
405  * acpi_ec_submit_flushable_request() - Increase the reference count unless
406  *                                      the flush operation is not in
407  *                                      progress
408  * @ec: the EC device
409  *
410  * This function must be used before taking a new action that should hold
411  * the reference count.  If this function returns false, then the action
412  * must be discarded or it will prevent the flush operation from being
413  * completed.
414  */
415 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
416 {
417         if (!acpi_ec_started(ec))
418                 return false;
419         acpi_ec_submit_request(ec);
420         return true;
421 }
422 
423 static void acpi_ec_submit_query(struct acpi_ec *ec)
424 {
425         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
426                 ec_dbg_evt("Command(%s) submitted/blocked",
427                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
428                 ec->nr_pending_queries++;
429                 schedule_work(&ec->work);
430         }
431 }
432 
433 static void acpi_ec_complete_query(struct acpi_ec *ec)
434 {
435         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
436                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
437                 ec_dbg_evt("Command(%s) unblocked",
438                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
439         }
440 }
441 
442 static bool acpi_ec_guard_event(struct acpi_ec *ec)
443 {
444         bool guarded = true;
445         unsigned long flags;
446 
447         spin_lock_irqsave(&ec->lock, flags);
448         /*
449          * If firmware SCI_EVT clearing timing is "event", we actually
450          * don't know when the SCI_EVT will be cleared by firmware after
451          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
452          * acceptable period.
453          *
454          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
455          * flagged, which means SCI_EVT check has just been performed.
456          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
457          * guarding should have already been performed (via
458          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
459          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
460          * ACPI_EC_COMMAND_POLL state immediately.
461          */
462         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
463             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
464             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
465             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
466                 guarded = false;
467         spin_unlock_irqrestore(&ec->lock, flags);
468         return guarded;
469 }
470 
471 static int ec_transaction_polled(struct acpi_ec *ec)
472 {
473         unsigned long flags;
474         int ret = 0;
475 
476         spin_lock_irqsave(&ec->lock, flags);
477         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
478                 ret = 1;
479         spin_unlock_irqrestore(&ec->lock, flags);
480         return ret;
481 }
482 
483 static int ec_transaction_completed(struct acpi_ec *ec)
484 {
485         unsigned long flags;
486         int ret = 0;
487 
488         spin_lock_irqsave(&ec->lock, flags);
489         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
490                 ret = 1;
491         spin_unlock_irqrestore(&ec->lock, flags);
492         return ret;
493 }
494 
495 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
496 {
497         ec->curr->flags |= flag;
498         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
499                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
500                     flag == ACPI_EC_COMMAND_POLL)
501                         acpi_ec_complete_query(ec);
502                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
503                     flag == ACPI_EC_COMMAND_COMPLETE)
504                         acpi_ec_complete_query(ec);
505                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
506                     flag == ACPI_EC_COMMAND_COMPLETE)
507                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
508         }
509 }
510 
511 static void advance_transaction(struct acpi_ec *ec)
512 {
513         struct transaction *t;
514         u8 status;
515         bool wakeup = false;
516 
517         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
518                    smp_processor_id());
519         /*
520          * By always clearing STS before handling all indications, we can
521          * ensure a hardware STS 0->1 change after this clearing can always
522          * trigger a GPE interrupt.
523          */
524         acpi_ec_clear_gpe(ec);
525         status = acpi_ec_read_status(ec);
526         t = ec->curr;
527         /*
528          * Another IRQ or a guarded polling mode advancement is detected,
529          * the next QR_EC submission is then allowed.
530          */
531         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
532                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
533                     (!ec->nr_pending_queries ||
534                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
535                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
536                         acpi_ec_complete_query(ec);
537                 }
538         }
539         if (!t)
540                 goto err;
541         if (t->flags & ACPI_EC_COMMAND_POLL) {
542                 if (t->wlen > t->wi) {
543                         if ((status & ACPI_EC_FLAG_IBF) == 0)
544                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
545                         else
546                                 goto err;
547                 } else if (t->rlen > t->ri) {
548                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
549                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
550                                 if (t->rlen == t->ri) {
551                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
552                                         if (t->command == ACPI_EC_COMMAND_QUERY)
553                                                 ec_dbg_evt("Command(%s) completed by hardware",
554                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
555                                         wakeup = true;
556                                 }
557                         } else
558                                 goto err;
559                 } else if (t->wlen == t->wi &&
560                            (status & ACPI_EC_FLAG_IBF) == 0) {
561                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
562                         wakeup = true;
563                 }
564                 goto out;
565         } else {
566                 if (EC_FLAGS_QUERY_HANDSHAKE &&
567                     !(status & ACPI_EC_FLAG_SCI) &&
568                     (t->command == ACPI_EC_COMMAND_QUERY)) {
569                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
570                         t->rdata[t->ri++] = 0x00;
571                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
572                         ec_dbg_evt("Command(%s) completed by software",
573                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
574                         wakeup = true;
575                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
576                         acpi_ec_write_cmd(ec, t->command);
577                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
578                 } else
579                         goto err;
580                 goto out;
581         }
582 err:
583         /*
584          * If SCI bit is set, then don't think it's a false IRQ
585          * otherwise will take a not handled IRQ as a false one.
586          */
587         if (!(status & ACPI_EC_FLAG_SCI)) {
588                 if (in_interrupt() && t) {
589                         if (t->irq_count < ec_storm_threshold)
590                                 ++t->irq_count;
591                         /* Allow triggering on 0 threshold */
592                         if (t->irq_count == ec_storm_threshold)
593                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
594                 }
595         }
596 out:
597         if (status & ACPI_EC_FLAG_SCI)
598                 acpi_ec_submit_query(ec);
599         if (wakeup && in_interrupt())
600                 wake_up(&ec->wait);
601 }
602 
603 static void start_transaction(struct acpi_ec *ec)
604 {
605         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
606         ec->curr->flags = 0;
607 }
608 
609 static int ec_guard(struct acpi_ec *ec)
610 {
611         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
612         unsigned long timeout = ec->timestamp + guard;
613 
614         /* Ensure guarding period before polling EC status */
615         do {
616                 if (ec_busy_polling) {
617                         /* Perform busy polling */
618                         if (ec_transaction_completed(ec))
619                                 return 0;
620                         udelay(jiffies_to_usecs(guard));
621                 } else {
622                         /*
623                          * Perform wait polling
624                          * 1. Wait the transaction to be completed by the
625                          *    GPE handler after the transaction enters
626                          *    ACPI_EC_COMMAND_POLL state.
627                          * 2. A special guarding logic is also required
628                          *    for event clearing mode "event" before the
629                          *    transaction enters ACPI_EC_COMMAND_POLL
630                          *    state.
631                          */
632                         if (!ec_transaction_polled(ec) &&
633                             !acpi_ec_guard_event(ec))
634                                 break;
635                         if (wait_event_timeout(ec->wait,
636                                                ec_transaction_completed(ec),
637                                                guard))
638                                 return 0;
639                 }
640         } while (time_before(jiffies, timeout));
641         return -ETIME;
642 }
643 
644 static int ec_poll(struct acpi_ec *ec)
645 {
646         unsigned long flags;
647         int repeat = 5; /* number of command restarts */
648 
649         while (repeat--) {
650                 unsigned long delay = jiffies +
651                         msecs_to_jiffies(ec_delay);
652                 do {
653                         if (!ec_guard(ec))
654                                 return 0;
655                         spin_lock_irqsave(&ec->lock, flags);
656                         advance_transaction(ec);
657                         spin_unlock_irqrestore(&ec->lock, flags);
658                 } while (time_before(jiffies, delay));
659                 pr_debug("controller reset, restart transaction\n");
660                 spin_lock_irqsave(&ec->lock, flags);
661                 start_transaction(ec);
662                 spin_unlock_irqrestore(&ec->lock, flags);
663         }
664         return -ETIME;
665 }
666 
667 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
668                                         struct transaction *t)
669 {
670         unsigned long tmp;
671         int ret = 0;
672 
673         /* start transaction */
674         spin_lock_irqsave(&ec->lock, tmp);
675         /* Enable GPE for command processing (IBF=0/OBF=1) */
676         if (!acpi_ec_submit_flushable_request(ec)) {
677                 ret = -EINVAL;
678                 goto unlock;
679         }
680         ec_dbg_ref(ec, "Increase command");
681         /* following two actions should be kept atomic */
682         ec->curr = t;
683         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
684         start_transaction(ec);
685         spin_unlock_irqrestore(&ec->lock, tmp);
686 
687         ret = ec_poll(ec);
688 
689         spin_lock_irqsave(&ec->lock, tmp);
690         if (t->irq_count == ec_storm_threshold)
691                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
692         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
693         ec->curr = NULL;
694         /* Disable GPE for command processing (IBF=0/OBF=1) */
695         acpi_ec_complete_request(ec);
696         ec_dbg_ref(ec, "Decrease command");
697 unlock:
698         spin_unlock_irqrestore(&ec->lock, tmp);
699         return ret;
700 }
701 
702 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
703 {
704         int status;
705         u32 glk;
706 
707         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
708                 return -EINVAL;
709         if (t->rdata)
710                 memset(t->rdata, 0, t->rlen);
711 
712         mutex_lock(&ec->mutex);
713         if (ec->global_lock) {
714                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
715                 if (ACPI_FAILURE(status)) {
716                         status = -ENODEV;
717                         goto unlock;
718                 }
719         }
720 
721         status = acpi_ec_transaction_unlocked(ec, t);
722 
723         if (ec->global_lock)
724                 acpi_release_global_lock(glk);
725 unlock:
726         mutex_unlock(&ec->mutex);
727         return status;
728 }
729 
730 static int acpi_ec_burst_enable(struct acpi_ec *ec)
731 {
732         u8 d;
733         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
734                                 .wdata = NULL, .rdata = &d,
735                                 .wlen = 0, .rlen = 1};
736 
737         return acpi_ec_transaction(ec, &t);
738 }
739 
740 static int acpi_ec_burst_disable(struct acpi_ec *ec)
741 {
742         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
743                                 .wdata = NULL, .rdata = NULL,
744                                 .wlen = 0, .rlen = 0};
745 
746         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
747                                 acpi_ec_transaction(ec, &t) : 0;
748 }
749 
750 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
751 {
752         int result;
753         u8 d;
754         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
755                                 .wdata = &address, .rdata = &d,
756                                 .wlen = 1, .rlen = 1};
757 
758         result = acpi_ec_transaction(ec, &t);
759         *data = d;
760         return result;
761 }
762 
763 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
764 {
765         u8 wdata[2] = { address, data };
766         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
767                                 .wdata = wdata, .rdata = NULL,
768                                 .wlen = 2, .rlen = 0};
769 
770         return acpi_ec_transaction(ec, &t);
771 }
772 
773 int ec_read(u8 addr, u8 *val)
774 {
775         int err;
776         u8 temp_data;
777 
778         if (!first_ec)
779                 return -ENODEV;
780 
781         err = acpi_ec_read(first_ec, addr, &temp_data);
782 
783         if (!err) {
784                 *val = temp_data;
785                 return 0;
786         }
787         return err;
788 }
789 EXPORT_SYMBOL(ec_read);
790 
791 int ec_write(u8 addr, u8 val)
792 {
793         int err;
794 
795         if (!first_ec)
796                 return -ENODEV;
797 
798         err = acpi_ec_write(first_ec, addr, val);
799 
800         return err;
801 }
802 EXPORT_SYMBOL(ec_write);
803 
804 int ec_transaction(u8 command,
805                    const u8 *wdata, unsigned wdata_len,
806                    u8 *rdata, unsigned rdata_len)
807 {
808         struct transaction t = {.command = command,
809                                 .wdata = wdata, .rdata = rdata,
810                                 .wlen = wdata_len, .rlen = rdata_len};
811 
812         if (!first_ec)
813                 return -ENODEV;
814 
815         return acpi_ec_transaction(first_ec, &t);
816 }
817 EXPORT_SYMBOL(ec_transaction);
818 
819 /* Get the handle to the EC device */
820 acpi_handle ec_get_handle(void)
821 {
822         if (!first_ec)
823                 return NULL;
824         return first_ec->handle;
825 }
826 EXPORT_SYMBOL(ec_get_handle);
827 
828 /*
829  * Process _Q events that might have accumulated in the EC.
830  * Run with locked ec mutex.
831  */
832 static void acpi_ec_clear(struct acpi_ec *ec)
833 {
834         int i, status;
835         u8 value = 0;
836 
837         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
838                 status = acpi_ec_query(ec, &value);
839                 if (status || !value)
840                         break;
841         }
842 
843         if (unlikely(i == ACPI_EC_CLEAR_MAX))
844                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
845         else
846                 pr_info("%d stale EC events cleared\n", i);
847 }
848 
849 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
850 {
851         unsigned long flags;
852 
853         spin_lock_irqsave(&ec->lock, flags);
854         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
855                 ec_dbg_drv("Starting EC");
856                 /* Enable GPE for event processing (SCI_EVT=1) */
857                 if (!resuming) {
858                         acpi_ec_submit_request(ec);
859                         ec_dbg_ref(ec, "Increase driver");
860                 }
861                 ec_log_drv("EC started");
862         }
863         spin_unlock_irqrestore(&ec->lock, flags);
864 }
865 
866 static bool acpi_ec_stopped(struct acpi_ec *ec)
867 {
868         unsigned long flags;
869         bool flushed;
870 
871         spin_lock_irqsave(&ec->lock, flags);
872         flushed = acpi_ec_flushed(ec);
873         spin_unlock_irqrestore(&ec->lock, flags);
874         return flushed;
875 }
876 
877 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
878 {
879         unsigned long flags;
880 
881         spin_lock_irqsave(&ec->lock, flags);
882         if (acpi_ec_started(ec)) {
883                 ec_dbg_drv("Stopping EC");
884                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
885                 spin_unlock_irqrestore(&ec->lock, flags);
886                 wait_event(ec->wait, acpi_ec_stopped(ec));
887                 spin_lock_irqsave(&ec->lock, flags);
888                 /* Disable GPE for event processing (SCI_EVT=1) */
889                 if (!suspending) {
890                         acpi_ec_complete_request(ec);
891                         ec_dbg_ref(ec, "Decrease driver");
892                 }
893                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
894                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
895                 ec_log_drv("EC stopped");
896         }
897         spin_unlock_irqrestore(&ec->lock, flags);
898 }
899 
900 void acpi_ec_block_transactions(void)
901 {
902         struct acpi_ec *ec = first_ec;
903 
904         if (!ec)
905                 return;
906 
907         mutex_lock(&ec->mutex);
908         /* Prevent transactions from being carried out */
909         acpi_ec_stop(ec, true);
910         mutex_unlock(&ec->mutex);
911 }
912 
913 void acpi_ec_unblock_transactions(void)
914 {
915         struct acpi_ec *ec = first_ec;
916 
917         if (!ec)
918                 return;
919 
920         /* Allow transactions to be carried out again */
921         acpi_ec_start(ec, true);
922 
923         if (EC_FLAGS_CLEAR_ON_RESUME)
924                 acpi_ec_clear(ec);
925 }
926 
927 void acpi_ec_unblock_transactions_early(void)
928 {
929         /*
930          * Allow transactions to happen again (this function is called from
931          * atomic context during wakeup, so we don't need to acquire the mutex).
932          */
933         if (first_ec)
934                 acpi_ec_start(first_ec, true);
935 }
936 
937 /* --------------------------------------------------------------------------
938                                 Event Management
939    -------------------------------------------------------------------------- */
940 static struct acpi_ec_query_handler *
941 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
942 {
943         if (handler)
944                 kref_get(&handler->kref);
945         return handler;
946 }
947 
948 static struct acpi_ec_query_handler *
949 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
950 {
951         struct acpi_ec_query_handler *handler;
952         bool found = false;
953 
954         mutex_lock(&ec->mutex);
955         list_for_each_entry(handler, &ec->list, node) {
956                 if (value == handler->query_bit) {
957                         found = true;
958                         break;
959                 }
960         }
961         mutex_unlock(&ec->mutex);
962         return found ? acpi_ec_get_query_handler(handler) : NULL;
963 }
964 
965 static void acpi_ec_query_handler_release(struct kref *kref)
966 {
967         struct acpi_ec_query_handler *handler =
968                 container_of(kref, struct acpi_ec_query_handler, kref);
969 
970         kfree(handler);
971 }
972 
973 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
974 {
975         kref_put(&handler->kref, acpi_ec_query_handler_release);
976 }
977 
978 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
979                               acpi_handle handle, acpi_ec_query_func func,
980                               void *data)
981 {
982         struct acpi_ec_query_handler *handler =
983             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
984 
985         if (!handler)
986                 return -ENOMEM;
987 
988         handler->query_bit = query_bit;
989         handler->handle = handle;
990         handler->func = func;
991         handler->data = data;
992         mutex_lock(&ec->mutex);
993         kref_init(&handler->kref);
994         list_add(&handler->node, &ec->list);
995         mutex_unlock(&ec->mutex);
996         return 0;
997 }
998 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
999 
1000 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1001                                           bool remove_all, u8 query_bit)
1002 {
1003         struct acpi_ec_query_handler *handler, *tmp;
1004         LIST_HEAD(free_list);
1005 
1006         mutex_lock(&ec->mutex);
1007         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1008                 if (remove_all || query_bit == handler->query_bit) {
1009                         list_del_init(&handler->node);
1010                         list_add(&handler->node, &free_list);
1011                 }
1012         }
1013         mutex_unlock(&ec->mutex);
1014         list_for_each_entry_safe(handler, tmp, &free_list, node)
1015                 acpi_ec_put_query_handler(handler);
1016 }
1017 
1018 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1019 {
1020         acpi_ec_remove_query_handlers(ec, false, query_bit);
1021 }
1022 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1023 
1024 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1025 {
1026         struct acpi_ec_query *q;
1027         struct transaction *t;
1028 
1029         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1030         if (!q)
1031                 return NULL;
1032         INIT_WORK(&q->work, acpi_ec_event_processor);
1033         t = &q->transaction;
1034         t->command = ACPI_EC_COMMAND_QUERY;
1035         t->rdata = pval;
1036         t->rlen = 1;
1037         return q;
1038 }
1039 
1040 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1041 {
1042         if (q) {
1043                 if (q->handler)
1044                         acpi_ec_put_query_handler(q->handler);
1045                 kfree(q);
1046         }
1047 }
1048 
1049 static void acpi_ec_event_processor(struct work_struct *work)
1050 {
1051         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1052         struct acpi_ec_query_handler *handler = q->handler;
1053 
1054         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1055         if (handler->func)
1056                 handler->func(handler->data);
1057         else if (handler->handle)
1058                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1059         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1060         acpi_ec_delete_query(q);
1061 }
1062 
1063 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1064 {
1065         u8 value = 0;
1066         int result;
1067         struct acpi_ec_query *q;
1068 
1069         q = acpi_ec_create_query(&value);
1070         if (!q)
1071                 return -ENOMEM;
1072 
1073         /*
1074          * Query the EC to find out which _Qxx method we need to evaluate.
1075          * Note that successful completion of the query causes the ACPI_EC_SCI
1076          * bit to be cleared (and thus clearing the interrupt source).
1077          */
1078         result = acpi_ec_transaction(ec, &q->transaction);
1079         if (!value)
1080                 result = -ENODATA;
1081         if (result)
1082                 goto err_exit;
1083 
1084         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1085         if (!q->handler) {
1086                 result = -ENODATA;
1087                 goto err_exit;
1088         }
1089 
1090         /*
1091          * It is reported that _Qxx are evaluated in a parallel way on
1092          * Windows:
1093          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1094          *
1095          * Put this log entry before schedule_work() in order to make
1096          * it appearing before any other log entries occurred during the
1097          * work queue execution.
1098          */
1099         ec_dbg_evt("Query(0x%02x) scheduled", value);
1100         if (!schedule_work(&q->work)) {
1101                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1102                 result = -EBUSY;
1103         }
1104 
1105 err_exit:
1106         if (result)
1107                 acpi_ec_delete_query(q);
1108         if (data)
1109                 *data = value;
1110         return result;
1111 }
1112 
1113 static void acpi_ec_check_event(struct acpi_ec *ec)
1114 {
1115         unsigned long flags;
1116 
1117         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1118                 if (ec_guard(ec)) {
1119                         spin_lock_irqsave(&ec->lock, flags);
1120                         /*
1121                          * Take care of the SCI_EVT unless no one else is
1122                          * taking care of it.
1123                          */
1124                         if (!ec->curr)
1125                                 advance_transaction(ec);
1126                         spin_unlock_irqrestore(&ec->lock, flags);
1127                 }
1128         }
1129 }
1130 
1131 static void acpi_ec_event_handler(struct work_struct *work)
1132 {
1133         unsigned long flags;
1134         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1135 
1136         ec_dbg_evt("Event started");
1137 
1138         spin_lock_irqsave(&ec->lock, flags);
1139         while (ec->nr_pending_queries) {
1140                 spin_unlock_irqrestore(&ec->lock, flags);
1141                 (void)acpi_ec_query(ec, NULL);
1142                 spin_lock_irqsave(&ec->lock, flags);
1143                 ec->nr_pending_queries--;
1144                 /*
1145                  * Before exit, make sure that this work item can be
1146                  * scheduled again. There might be QR_EC failures, leaving
1147                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1148                  * item from being scheduled again.
1149                  */
1150                 if (!ec->nr_pending_queries) {
1151                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1152                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1153                                 acpi_ec_complete_query(ec);
1154                 }
1155         }
1156         spin_unlock_irqrestore(&ec->lock, flags);
1157 
1158         ec_dbg_evt("Event stopped");
1159 
1160         acpi_ec_check_event(ec);
1161 }
1162 
1163 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1164         u32 gpe_number, void *data)
1165 {
1166         unsigned long flags;
1167         struct acpi_ec *ec = data;
1168 
1169         spin_lock_irqsave(&ec->lock, flags);
1170         advance_transaction(ec);
1171         spin_unlock_irqrestore(&ec->lock, flags);
1172         return ACPI_INTERRUPT_HANDLED;
1173 }
1174 
1175 /* --------------------------------------------------------------------------
1176  *                           Address Space Management
1177  * -------------------------------------------------------------------------- */
1178 
1179 static acpi_status
1180 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1181                       u32 bits, u64 *value64,
1182                       void *handler_context, void *region_context)
1183 {
1184         struct acpi_ec *ec = handler_context;
1185         int result = 0, i, bytes = bits / 8;
1186         u8 *value = (u8 *)value64;
1187 
1188         if ((address > 0xFF) || !value || !handler_context)
1189                 return AE_BAD_PARAMETER;
1190 
1191         if (function != ACPI_READ && function != ACPI_WRITE)
1192                 return AE_BAD_PARAMETER;
1193 
1194         if (ec_busy_polling || bits > 8)
1195                 acpi_ec_burst_enable(ec);
1196 
1197         for (i = 0; i < bytes; ++i, ++address, ++value)
1198                 result = (function == ACPI_READ) ?
1199                         acpi_ec_read(ec, address, value) :
1200                         acpi_ec_write(ec, address, *value);
1201 
1202         if (ec_busy_polling || bits > 8)
1203                 acpi_ec_burst_disable(ec);
1204 
1205         switch (result) {
1206         case -EINVAL:
1207                 return AE_BAD_PARAMETER;
1208         case -ENODEV:
1209                 return AE_NOT_FOUND;
1210         case -ETIME:
1211                 return AE_TIME;
1212         default:
1213                 return AE_OK;
1214         }
1215 }
1216 
1217 /* --------------------------------------------------------------------------
1218  *                             Driver Interface
1219  * -------------------------------------------------------------------------- */
1220 
1221 static acpi_status
1222 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1223 
1224 static struct acpi_ec *make_acpi_ec(void)
1225 {
1226         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1227 
1228         if (!ec)
1229                 return NULL;
1230         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1231         mutex_init(&ec->mutex);
1232         init_waitqueue_head(&ec->wait);
1233         INIT_LIST_HEAD(&ec->list);
1234         spin_lock_init(&ec->lock);
1235         INIT_WORK(&ec->work, acpi_ec_event_handler);
1236         ec->timestamp = jiffies;
1237         return ec;
1238 }
1239 
1240 static acpi_status
1241 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1242                                void *context, void **return_value)
1243 {
1244         char node_name[5];
1245         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1246         struct acpi_ec *ec = context;
1247         int value = 0;
1248         acpi_status status;
1249 
1250         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1251 
1252         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1253                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1254         return AE_OK;
1255 }
1256 
1257 static acpi_status
1258 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1259 {
1260         acpi_status status;
1261         unsigned long long tmp = 0;
1262         struct acpi_ec *ec = context;
1263 
1264         /* clear addr values, ec_parse_io_ports depend on it */
1265         ec->command_addr = ec->data_addr = 0;
1266 
1267         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1268                                      ec_parse_io_ports, ec);
1269         if (ACPI_FAILURE(status))
1270                 return status;
1271 
1272         /* Get GPE bit assignment (EC events). */
1273         /* TODO: Add support for _GPE returning a package */
1274         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1275         if (ACPI_FAILURE(status))
1276                 return status;
1277         ec->gpe = tmp;
1278         /* Use the global lock for all EC transactions? */
1279         tmp = 0;
1280         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1281         ec->global_lock = tmp;
1282         ec->handle = handle;
1283         return AE_CTRL_TERMINATE;
1284 }
1285 
1286 static int ec_install_handlers(struct acpi_ec *ec)
1287 {
1288         acpi_status status;
1289 
1290         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1291                 return 0;
1292         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1293                                   ACPI_GPE_EDGE_TRIGGERED,
1294                                   &acpi_ec_gpe_handler, ec);
1295         if (ACPI_FAILURE(status))
1296                 return -ENODEV;
1297 
1298         acpi_ec_start(ec, false);
1299         status = acpi_install_address_space_handler(ec->handle,
1300                                                     ACPI_ADR_SPACE_EC,
1301                                                     &acpi_ec_space_handler,
1302                                                     NULL, ec);
1303         if (ACPI_FAILURE(status)) {
1304                 if (status == AE_NOT_FOUND) {
1305                         /*
1306                          * Maybe OS fails in evaluating the _REG object.
1307                          * The AE_NOT_FOUND error will be ignored and OS
1308                          * continue to initialize EC.
1309                          */
1310                         pr_err("Fail in evaluating the _REG object"
1311                                 " of EC device. Broken bios is suspected.\n");
1312                 } else {
1313                         acpi_ec_stop(ec, false);
1314                         acpi_remove_gpe_handler(NULL, ec->gpe,
1315                                 &acpi_ec_gpe_handler);
1316                         return -ENODEV;
1317                 }
1318         }
1319 
1320         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1321         return 0;
1322 }
1323 
1324 static void ec_remove_handlers(struct acpi_ec *ec)
1325 {
1326         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1327                 return;
1328         acpi_ec_stop(ec, false);
1329         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1330                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1331                 pr_err("failed to remove space handler\n");
1332         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1333                                 &acpi_ec_gpe_handler)))
1334                 pr_err("failed to remove gpe handler\n");
1335         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1336 }
1337 
1338 static int acpi_ec_add(struct acpi_device *device)
1339 {
1340         struct acpi_ec *ec = NULL;
1341         int ret;
1342 
1343         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1344         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1345 
1346         /* Check for boot EC */
1347         if (boot_ec &&
1348             (boot_ec->handle == device->handle ||
1349              boot_ec->handle == ACPI_ROOT_OBJECT)) {
1350                 ec = boot_ec;
1351                 boot_ec = NULL;
1352         } else {
1353                 ec = make_acpi_ec();
1354                 if (!ec)
1355                         return -ENOMEM;
1356         }
1357         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1358                 AE_CTRL_TERMINATE) {
1359                         kfree(ec);
1360                         return -EINVAL;
1361         }
1362 
1363         /* Find and register all query methods */
1364         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1365                             acpi_ec_register_query_methods, NULL, ec, NULL);
1366 
1367         if (!first_ec)
1368                 first_ec = ec;
1369         device->driver_data = ec;
1370 
1371         ret = !!request_region(ec->data_addr, 1, "EC data");
1372         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1373         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1374         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1375 
1376         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1377                           ec->gpe, ec->command_addr, ec->data_addr);
1378 
1379         ret = ec_install_handlers(ec);
1380 
1381         /* Reprobe devices depending on the EC */
1382         acpi_walk_dep_device_list(ec->handle);
1383 
1384         /* EC is fully operational, allow queries */
1385         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1386 
1387         /* Clear stale _Q events if hardware might require that */
1388         if (EC_FLAGS_CLEAR_ON_RESUME)
1389                 acpi_ec_clear(ec);
1390         return ret;
1391 }
1392 
1393 static int acpi_ec_remove(struct acpi_device *device)
1394 {
1395         struct acpi_ec *ec;
1396 
1397         if (!device)
1398                 return -EINVAL;
1399 
1400         ec = acpi_driver_data(device);
1401         ec_remove_handlers(ec);
1402         acpi_ec_remove_query_handlers(ec, true, 0);
1403         release_region(ec->data_addr, 1);
1404         release_region(ec->command_addr, 1);
1405         device->driver_data = NULL;
1406         if (ec == first_ec)
1407                 first_ec = NULL;
1408         kfree(ec);
1409         return 0;
1410 }
1411 
1412 static acpi_status
1413 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1414 {
1415         struct acpi_ec *ec = context;
1416 
1417         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1418                 return AE_OK;
1419 
1420         /*
1421          * The first address region returned is the data port, and
1422          * the second address region returned is the status/command
1423          * port.
1424          */
1425         if (ec->data_addr == 0)
1426                 ec->data_addr = resource->data.io.minimum;
1427         else if (ec->command_addr == 0)
1428                 ec->command_addr = resource->data.io.minimum;
1429         else
1430                 return AE_CTRL_TERMINATE;
1431 
1432         return AE_OK;
1433 }
1434 
1435 int __init acpi_boot_ec_enable(void)
1436 {
1437         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1438                 return 0;
1439         if (!ec_install_handlers(boot_ec)) {
1440                 first_ec = boot_ec;
1441                 return 0;
1442         }
1443         return -EFAULT;
1444 }
1445 
1446 static const struct acpi_device_id ec_device_ids[] = {
1447         {"PNP0C09", 0},
1448         {"", 0},
1449 };
1450 
1451 /* Some BIOS do not survive early DSDT scan, skip it */
1452 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1453 {
1454         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1455         return 0;
1456 }
1457 
1458 /* ASUStek often supplies us with broken ECDT, validate it */
1459 static int ec_validate_ecdt(const struct dmi_system_id *id)
1460 {
1461         EC_FLAGS_VALIDATE_ECDT = 1;
1462         return 0;
1463 }
1464 
1465 #if 0
1466 /*
1467  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1468  * set, for which case, we complete the QR_EC without issuing it to the
1469  * firmware.
1470  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1471  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1472  */
1473 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1474 {
1475         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1476         EC_FLAGS_QUERY_HANDSHAKE = 1;
1477         return 0;
1478 }
1479 #endif
1480 
1481 /*
1482  * On some hardware it is necessary to clear events accumulated by the EC during
1483  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1484  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1485  *
1486  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1487  *
1488  * Ideally, the EC should also be instructed NOT to accumulate events during
1489  * sleep (which Windows seems to do somehow), but the interface to control this
1490  * behaviour is not known at this time.
1491  *
1492  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1493  * however it is very likely that other Samsung models are affected.
1494  *
1495  * On systems which don't accumulate _Q events during sleep, this extra check
1496  * should be harmless.
1497  */
1498 static int ec_clear_on_resume(const struct dmi_system_id *id)
1499 {
1500         pr_debug("Detected system needing EC poll on resume.\n");
1501         EC_FLAGS_CLEAR_ON_RESUME = 1;
1502         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1503         return 0;
1504 }
1505 
1506 static struct dmi_system_id ec_dmi_table[] __initdata = {
1507         {
1508         ec_skip_dsdt_scan, "Compal JFL92", {
1509         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1510         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1511         {
1512         ec_validate_ecdt, "MSI MS-171F", {
1513         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1514         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1515         {
1516         ec_validate_ecdt, "ASUS hardware", {
1517         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1518         {
1519         ec_validate_ecdt, "ASUS hardware", {
1520         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1521         {
1522         ec_skip_dsdt_scan, "HP Folio 13", {
1523         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1524         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1525         {
1526         ec_validate_ecdt, "ASUS hardware", {
1527         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1528         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1529         {
1530         ec_clear_on_resume, "Samsung hardware", {
1531         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1532         {},
1533 };
1534 
1535 int __init acpi_ec_ecdt_probe(void)
1536 {
1537         acpi_status status;
1538         struct acpi_ec *saved_ec = NULL;
1539         struct acpi_table_ecdt *ecdt_ptr;
1540 
1541         boot_ec = make_acpi_ec();
1542         if (!boot_ec)
1543                 return -ENOMEM;
1544         /*
1545          * Generate a boot ec context
1546          */
1547         dmi_check_system(ec_dmi_table);
1548         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1549                                 (struct acpi_table_header **)&ecdt_ptr);
1550         if (ACPI_SUCCESS(status)) {
1551                 pr_info("EC description table is found, configuring boot EC\n");
1552                 boot_ec->command_addr = ecdt_ptr->control.address;
1553                 boot_ec->data_addr = ecdt_ptr->data.address;
1554                 boot_ec->gpe = ecdt_ptr->gpe;
1555                 boot_ec->handle = ACPI_ROOT_OBJECT;
1556                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1557                                 &boot_ec->handle);
1558                 /* Don't trust ECDT, which comes from ASUSTek */
1559                 if (!EC_FLAGS_VALIDATE_ECDT)
1560                         goto install;
1561                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1562                 if (!saved_ec)
1563                         return -ENOMEM;
1564         /* fall through */
1565         }
1566 
1567         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1568                 kfree(saved_ec);
1569                 return -ENODEV;
1570         }
1571 
1572         /* This workaround is needed only on some broken machines,
1573          * which require early EC, but fail to provide ECDT */
1574         pr_debug("Look up EC in DSDT\n");
1575         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1576                                         boot_ec, NULL);
1577         /* Check that acpi_get_devices actually find something */
1578         if (ACPI_FAILURE(status) || !boot_ec->handle)
1579                 goto error;
1580         if (saved_ec) {
1581                 /* try to find good ECDT from ASUSTek */
1582                 if (saved_ec->command_addr != boot_ec->command_addr ||
1583                     saved_ec->data_addr != boot_ec->data_addr ||
1584                     saved_ec->gpe != boot_ec->gpe ||
1585                     saved_ec->handle != boot_ec->handle)
1586                         pr_info("ASUSTek keeps feeding us with broken "
1587                         "ECDT tables, which are very hard to workaround. "
1588                         "Trying to use DSDT EC info instead. Please send "
1589                         "output of acpidump to linux-acpi@vger.kernel.org\n");
1590                 kfree(saved_ec);
1591                 saved_ec = NULL;
1592         } else {
1593                 /* We really need to limit this workaround, the only ASUS,
1594                 * which needs it, has fake EC._INI method, so use it as flag.
1595                 * Keep boot_ec struct as it will be needed soon.
1596                 */
1597                 if (!dmi_name_in_vendors("ASUS") ||
1598                     !acpi_has_method(boot_ec->handle, "_INI"))
1599                         return -ENODEV;
1600         }
1601 install:
1602         if (!ec_install_handlers(boot_ec)) {
1603                 first_ec = boot_ec;
1604                 return 0;
1605         }
1606 error:
1607         kfree(boot_ec);
1608         kfree(saved_ec);
1609         boot_ec = NULL;
1610         return -ENODEV;
1611 }
1612 
1613 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1614 {
1615         int result = 0;
1616 
1617         if (!strncmp(val, "status", sizeof("status") - 1)) {
1618                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1619                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1620         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1621                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1622                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1623         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1624                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1625                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1626         } else
1627                 result = -EINVAL;
1628         return result;
1629 }
1630 
1631 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1632 {
1633         switch (ec_event_clearing) {
1634         case ACPI_EC_EVT_TIMING_STATUS:
1635                 return sprintf(buffer, "status");
1636         case ACPI_EC_EVT_TIMING_QUERY:
1637                 return sprintf(buffer, "query");
1638         case ACPI_EC_EVT_TIMING_EVENT:
1639                 return sprintf(buffer, "event");
1640         default:
1641                 return sprintf(buffer, "invalid");
1642         }
1643         return 0;
1644 }
1645 
1646 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1647                   NULL, 0644);
1648 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1649 
1650 static struct acpi_driver acpi_ec_driver = {
1651         .name = "ec",
1652         .class = ACPI_EC_CLASS,
1653         .ids = ec_device_ids,
1654         .ops = {
1655                 .add = acpi_ec_add,
1656                 .remove = acpi_ec_remove,
1657                 },
1658 };
1659 
1660 int __init acpi_ec_init(void)
1661 {
1662         int result = 0;
1663 
1664         /* Now register the driver for the EC */
1665         result = acpi_bus_register_driver(&acpi_ec_driver);
1666         if (result < 0)
1667                 return -ENODEV;
1668 
1669         return result;
1670 }
1671 
1672 /* EC driver currently not unloadable */
1673 #if 0
1674 static void __exit acpi_ec_exit(void)
1675 {
1676 
1677         acpi_bus_unregister_driver(&acpi_ec_driver);
1678 }
1679 #endif  /* 0 */
1680 

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