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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_GPE_HANDLER_INSTALLED, /* GPE handler installed */
109         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler 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_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
179 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
180 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
181 
182 /* --------------------------------------------------------------------------
183  *                           Logging/Debugging
184  * -------------------------------------------------------------------------- */
185 
186 /*
187  * Splitters used by the developers to track the boundary of the EC
188  * handling processes.
189  */
190 #ifdef DEBUG
191 #define EC_DBG_SEP      " "
192 #define EC_DBG_DRV      "+++++"
193 #define EC_DBG_STM      "====="
194 #define EC_DBG_REQ      "*****"
195 #define EC_DBG_EVT      "#####"
196 #else
197 #define EC_DBG_SEP      ""
198 #define EC_DBG_DRV
199 #define EC_DBG_STM
200 #define EC_DBG_REQ
201 #define EC_DBG_EVT
202 #endif
203 
204 #define ec_log_raw(fmt, ...) \
205         pr_info(fmt "\n", ##__VA_ARGS__)
206 #define ec_dbg_raw(fmt, ...) \
207         pr_debug(fmt "\n", ##__VA_ARGS__)
208 #define ec_log(filter, fmt, ...) \
209         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
210 #define ec_dbg(filter, fmt, ...) \
211         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
212 
213 #define ec_log_drv(fmt, ...) \
214         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
215 #define ec_dbg_drv(fmt, ...) \
216         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
217 #define ec_dbg_stm(fmt, ...) \
218         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
219 #define ec_dbg_req(fmt, ...) \
220         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
221 #define ec_dbg_evt(fmt, ...) \
222         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
223 #define ec_dbg_ref(ec, fmt, ...) \
224         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
225 
226 /* --------------------------------------------------------------------------
227  *                           Device Flags
228  * -------------------------------------------------------------------------- */
229 
230 static bool acpi_ec_started(struct acpi_ec *ec)
231 {
232         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
233                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
234 }
235 
236 static bool acpi_ec_flushed(struct acpi_ec *ec)
237 {
238         return ec->reference_count == 1;
239 }
240 
241 /* --------------------------------------------------------------------------
242  *                           EC Registers
243  * -------------------------------------------------------------------------- */
244 
245 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
246 {
247         u8 x = inb(ec->command_addr);
248 
249         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
250                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
251                    x,
252                    !!(x & ACPI_EC_FLAG_SCI),
253                    !!(x & ACPI_EC_FLAG_BURST),
254                    !!(x & ACPI_EC_FLAG_CMD),
255                    !!(x & ACPI_EC_FLAG_IBF),
256                    !!(x & ACPI_EC_FLAG_OBF));
257         return x;
258 }
259 
260 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
261 {
262         u8 x = inb(ec->data_addr);
263 
264         ec->timestamp = jiffies;
265         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
266         return x;
267 }
268 
269 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
270 {
271         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
272         outb(command, ec->command_addr);
273         ec->timestamp = jiffies;
274 }
275 
276 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
277 {
278         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
279         outb(data, ec->data_addr);
280         ec->timestamp = jiffies;
281 }
282 
283 #ifdef DEBUG
284 static const char *acpi_ec_cmd_string(u8 cmd)
285 {
286         switch (cmd) {
287         case 0x80:
288                 return "RD_EC";
289         case 0x81:
290                 return "WR_EC";
291         case 0x82:
292                 return "BE_EC";
293         case 0x83:
294                 return "BD_EC";
295         case 0x84:
296                 return "QR_EC";
297         }
298         return "UNKNOWN";
299 }
300 #else
301 #define acpi_ec_cmd_string(cmd)         "UNDEF"
302 #endif
303 
304 /* --------------------------------------------------------------------------
305  *                           GPE Registers
306  * -------------------------------------------------------------------------- */
307 
308 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
309 {
310         acpi_event_status gpe_status = 0;
311 
312         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
313         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
314 }
315 
316 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
317 {
318         if (open)
319                 acpi_enable_gpe(NULL, ec->gpe);
320         else {
321                 BUG_ON(ec->reference_count < 1);
322                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
323         }
324         if (acpi_ec_is_gpe_raised(ec)) {
325                 /*
326                  * On some platforms, EN=1 writes cannot trigger GPE. So
327                  * software need to manually trigger a pseudo GPE event on
328                  * EN=1 writes.
329                  */
330                 ec_dbg_raw("Polling quirk");
331                 advance_transaction(ec);
332         }
333 }
334 
335 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
336 {
337         if (close)
338                 acpi_disable_gpe(NULL, ec->gpe);
339         else {
340                 BUG_ON(ec->reference_count < 1);
341                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
342         }
343 }
344 
345 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
346 {
347         /*
348          * GPE STS is a W1C register, which means:
349          * 1. Software can clear it without worrying about clearing other
350          *    GPEs' STS bits when the hardware sets them in parallel.
351          * 2. As long as software can ensure only clearing it when it is
352          *    set, hardware won't set it in parallel.
353          * So software can clear GPE in any contexts.
354          * Warning: do not move the check into advance_transaction() as the
355          * EC commands will be sent without GPE raised.
356          */
357         if (!acpi_ec_is_gpe_raised(ec))
358                 return;
359         acpi_clear_gpe(NULL, ec->gpe);
360 }
361 
362 /* --------------------------------------------------------------------------
363  *                           Transaction Management
364  * -------------------------------------------------------------------------- */
365 
366 static void acpi_ec_submit_request(struct acpi_ec *ec)
367 {
368         ec->reference_count++;
369         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
370             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 (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
380             ec->reference_count == 0)
381                 acpi_ec_disable_gpe(ec, true);
382         flushed = acpi_ec_flushed(ec);
383         if (flushed)
384                 wake_up(&ec->wait);
385 }
386 
387 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
388 {
389         if (!test_bit(flag, &ec->flags)) {
390                 acpi_ec_disable_gpe(ec, false);
391                 ec_dbg_drv("Polling enabled");
392                 set_bit(flag, &ec->flags);
393         }
394 }
395 
396 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
397 {
398         if (test_bit(flag, &ec->flags)) {
399                 clear_bit(flag, &ec->flags);
400                 acpi_ec_enable_gpe(ec, false);
401                 ec_dbg_drv("Polling disabled");
402         }
403 }
404 
405 /*
406  * acpi_ec_submit_flushable_request() - Increase the reference count unless
407  *                                      the flush operation is not in
408  *                                      progress
409  * @ec: the EC device
410  *
411  * This function must be used before taking a new action that should hold
412  * the reference count.  If this function returns false, then the action
413  * must be discarded or it will prevent the flush operation from being
414  * completed.
415  */
416 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
417 {
418         if (!acpi_ec_started(ec))
419                 return false;
420         acpi_ec_submit_request(ec);
421         return true;
422 }
423 
424 static void acpi_ec_submit_query(struct acpi_ec *ec)
425 {
426         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
427                 ec_dbg_evt("Command(%s) submitted/blocked",
428                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
429                 ec->nr_pending_queries++;
430                 schedule_work(&ec->work);
431         }
432 }
433 
434 static void acpi_ec_complete_query(struct acpi_ec *ec)
435 {
436         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
437                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
438                 ec_dbg_evt("Command(%s) unblocked",
439                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
440         }
441 }
442 
443 static bool acpi_ec_guard_event(struct acpi_ec *ec)
444 {
445         bool guarded = true;
446         unsigned long flags;
447 
448         spin_lock_irqsave(&ec->lock, flags);
449         /*
450          * If firmware SCI_EVT clearing timing is "event", we actually
451          * don't know when the SCI_EVT will be cleared by firmware after
452          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
453          * acceptable period.
454          *
455          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
456          * flagged, which means SCI_EVT check has just been performed.
457          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
458          * guarding should have already been performed (via
459          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
460          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
461          * ACPI_EC_COMMAND_POLL state immediately.
462          */
463         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
464             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
465             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
466             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
467                 guarded = false;
468         spin_unlock_irqrestore(&ec->lock, flags);
469         return guarded;
470 }
471 
472 static int ec_transaction_polled(struct acpi_ec *ec)
473 {
474         unsigned long flags;
475         int ret = 0;
476 
477         spin_lock_irqsave(&ec->lock, flags);
478         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
479                 ret = 1;
480         spin_unlock_irqrestore(&ec->lock, flags);
481         return ret;
482 }
483 
484 static int ec_transaction_completed(struct acpi_ec *ec)
485 {
486         unsigned long flags;
487         int ret = 0;
488 
489         spin_lock_irqsave(&ec->lock, flags);
490         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
491                 ret = 1;
492         spin_unlock_irqrestore(&ec->lock, flags);
493         return ret;
494 }
495 
496 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
497 {
498         ec->curr->flags |= flag;
499         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
500                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
501                     flag == ACPI_EC_COMMAND_POLL)
502                         acpi_ec_complete_query(ec);
503                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
504                     flag == ACPI_EC_COMMAND_COMPLETE)
505                         acpi_ec_complete_query(ec);
506                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
507                     flag == ACPI_EC_COMMAND_COMPLETE)
508                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
509         }
510 }
511 
512 static void advance_transaction(struct acpi_ec *ec)
513 {
514         struct transaction *t;
515         u8 status;
516         bool wakeup = false;
517 
518         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
519                    smp_processor_id());
520         /*
521          * By always clearing STS before handling all indications, we can
522          * ensure a hardware STS 0->1 change after this clearing can always
523          * trigger a GPE interrupt.
524          */
525         acpi_ec_clear_gpe(ec);
526         status = acpi_ec_read_status(ec);
527         t = ec->curr;
528         /*
529          * Another IRQ or a guarded polling mode advancement is detected,
530          * the next QR_EC submission is then allowed.
531          */
532         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
533                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
534                     (!ec->nr_pending_queries ||
535                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
536                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
537                         acpi_ec_complete_query(ec);
538                 }
539         }
540         if (!t)
541                 goto err;
542         if (t->flags & ACPI_EC_COMMAND_POLL) {
543                 if (t->wlen > t->wi) {
544                         if ((status & ACPI_EC_FLAG_IBF) == 0)
545                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
546                         else
547                                 goto err;
548                 } else if (t->rlen > t->ri) {
549                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
550                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
551                                 if (t->rlen == t->ri) {
552                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
553                                         if (t->command == ACPI_EC_COMMAND_QUERY)
554                                                 ec_dbg_evt("Command(%s) completed by hardware",
555                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
556                                         wakeup = true;
557                                 }
558                         } else
559                                 goto err;
560                 } else if (t->wlen == t->wi &&
561                            (status & ACPI_EC_FLAG_IBF) == 0) {
562                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
563                         wakeup = true;
564                 }
565                 goto out;
566         } else {
567                 if (EC_FLAGS_QUERY_HANDSHAKE &&
568                     !(status & ACPI_EC_FLAG_SCI) &&
569                     (t->command == ACPI_EC_COMMAND_QUERY)) {
570                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
571                         t->rdata[t->ri++] = 0x00;
572                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
573                         ec_dbg_evt("Command(%s) completed by software",
574                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
575                         wakeup = true;
576                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
577                         acpi_ec_write_cmd(ec, t->command);
578                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
579                 } else
580                         goto err;
581                 goto out;
582         }
583 err:
584         /*
585          * If SCI bit is set, then don't think it's a false IRQ
586          * otherwise will take a not handled IRQ as a false one.
587          */
588         if (!(status & ACPI_EC_FLAG_SCI)) {
589                 if (in_interrupt() && t) {
590                         if (t->irq_count < ec_storm_threshold)
591                                 ++t->irq_count;
592                         /* Allow triggering on 0 threshold */
593                         if (t->irq_count == ec_storm_threshold)
594                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
595                 }
596         }
597 out:
598         if (status & ACPI_EC_FLAG_SCI)
599                 acpi_ec_submit_query(ec);
600         if (wakeup && in_interrupt())
601                 wake_up(&ec->wait);
602 }
603 
604 static void start_transaction(struct acpi_ec *ec)
605 {
606         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
607         ec->curr->flags = 0;
608 }
609 
610 static int ec_guard(struct acpi_ec *ec)
611 {
612         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
613         unsigned long timeout = ec->timestamp + guard;
614 
615         /* Ensure guarding period before polling EC status */
616         do {
617                 if (ec_busy_polling) {
618                         /* Perform busy polling */
619                         if (ec_transaction_completed(ec))
620                                 return 0;
621                         udelay(jiffies_to_usecs(guard));
622                 } else {
623                         /*
624                          * Perform wait polling
625                          * 1. Wait the transaction to be completed by the
626                          *    GPE handler after the transaction enters
627                          *    ACPI_EC_COMMAND_POLL state.
628                          * 2. A special guarding logic is also required
629                          *    for event clearing mode "event" before the
630                          *    transaction enters ACPI_EC_COMMAND_POLL
631                          *    state.
632                          */
633                         if (!ec_transaction_polled(ec) &&
634                             !acpi_ec_guard_event(ec))
635                                 break;
636                         if (wait_event_timeout(ec->wait,
637                                                ec_transaction_completed(ec),
638                                                guard))
639                                 return 0;
640                 }
641         } while (time_before(jiffies, timeout));
642         return -ETIME;
643 }
644 
645 static int ec_poll(struct acpi_ec *ec)
646 {
647         unsigned long flags;
648         int repeat = 5; /* number of command restarts */
649 
650         while (repeat--) {
651                 unsigned long delay = jiffies +
652                         msecs_to_jiffies(ec_delay);
653                 do {
654                         if (!ec_guard(ec))
655                                 return 0;
656                         spin_lock_irqsave(&ec->lock, flags);
657                         advance_transaction(ec);
658                         spin_unlock_irqrestore(&ec->lock, flags);
659                 } while (time_before(jiffies, delay));
660                 pr_debug("controller reset, restart transaction\n");
661                 spin_lock_irqsave(&ec->lock, flags);
662                 start_transaction(ec);
663                 spin_unlock_irqrestore(&ec->lock, flags);
664         }
665         return -ETIME;
666 }
667 
668 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
669                                         struct transaction *t)
670 {
671         unsigned long tmp;
672         int ret = 0;
673 
674         /* start transaction */
675         spin_lock_irqsave(&ec->lock, tmp);
676         /* Enable GPE for command processing (IBF=0/OBF=1) */
677         if (!acpi_ec_submit_flushable_request(ec)) {
678                 ret = -EINVAL;
679                 goto unlock;
680         }
681         ec_dbg_ref(ec, "Increase command");
682         /* following two actions should be kept atomic */
683         ec->curr = t;
684         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
685         start_transaction(ec);
686         spin_unlock_irqrestore(&ec->lock, tmp);
687 
688         ret = ec_poll(ec);
689 
690         spin_lock_irqsave(&ec->lock, tmp);
691         if (t->irq_count == ec_storm_threshold)
692                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
693         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
694         ec->curr = NULL;
695         /* Disable GPE for command processing (IBF=0/OBF=1) */
696         acpi_ec_complete_request(ec);
697         ec_dbg_ref(ec, "Decrease command");
698 unlock:
699         spin_unlock_irqrestore(&ec->lock, tmp);
700         return ret;
701 }
702 
703 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
704 {
705         int status;
706         u32 glk;
707 
708         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
709                 return -EINVAL;
710         if (t->rdata)
711                 memset(t->rdata, 0, t->rlen);
712 
713         mutex_lock(&ec->mutex);
714         if (ec->global_lock) {
715                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
716                 if (ACPI_FAILURE(status)) {
717                         status = -ENODEV;
718                         goto unlock;
719                 }
720         }
721 
722         status = acpi_ec_transaction_unlocked(ec, t);
723 
724         if (ec->global_lock)
725                 acpi_release_global_lock(glk);
726 unlock:
727         mutex_unlock(&ec->mutex);
728         return status;
729 }
730 
731 static int acpi_ec_burst_enable(struct acpi_ec *ec)
732 {
733         u8 d;
734         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
735                                 .wdata = NULL, .rdata = &d,
736                                 .wlen = 0, .rlen = 1};
737 
738         return acpi_ec_transaction(ec, &t);
739 }
740 
741 static int acpi_ec_burst_disable(struct acpi_ec *ec)
742 {
743         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
744                                 .wdata = NULL, .rdata = NULL,
745                                 .wlen = 0, .rlen = 0};
746 
747         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
748                                 acpi_ec_transaction(ec, &t) : 0;
749 }
750 
751 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
752 {
753         int result;
754         u8 d;
755         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
756                                 .wdata = &address, .rdata = &d,
757                                 .wlen = 1, .rlen = 1};
758 
759         result = acpi_ec_transaction(ec, &t);
760         *data = d;
761         return result;
762 }
763 
764 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
765 {
766         u8 wdata[2] = { address, data };
767         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
768                                 .wdata = wdata, .rdata = NULL,
769                                 .wlen = 2, .rlen = 0};
770 
771         return acpi_ec_transaction(ec, &t);
772 }
773 
774 int ec_read(u8 addr, u8 *val)
775 {
776         int err;
777         u8 temp_data;
778 
779         if (!first_ec)
780                 return -ENODEV;
781 
782         err = acpi_ec_read(first_ec, addr, &temp_data);
783 
784         if (!err) {
785                 *val = temp_data;
786                 return 0;
787         }
788         return err;
789 }
790 EXPORT_SYMBOL(ec_read);
791 
792 int ec_write(u8 addr, u8 val)
793 {
794         int err;
795 
796         if (!first_ec)
797                 return -ENODEV;
798 
799         err = acpi_ec_write(first_ec, addr, val);
800 
801         return err;
802 }
803 EXPORT_SYMBOL(ec_write);
804 
805 int ec_transaction(u8 command,
806                    const u8 *wdata, unsigned wdata_len,
807                    u8 *rdata, unsigned rdata_len)
808 {
809         struct transaction t = {.command = command,
810                                 .wdata = wdata, .rdata = rdata,
811                                 .wlen = wdata_len, .rlen = rdata_len};
812 
813         if (!first_ec)
814                 return -ENODEV;
815 
816         return acpi_ec_transaction(first_ec, &t);
817 }
818 EXPORT_SYMBOL(ec_transaction);
819 
820 /* Get the handle to the EC device */
821 acpi_handle ec_get_handle(void)
822 {
823         if (!first_ec)
824                 return NULL;
825         return first_ec->handle;
826 }
827 EXPORT_SYMBOL(ec_get_handle);
828 
829 /*
830  * Process _Q events that might have accumulated in the EC.
831  * Run with locked ec mutex.
832  */
833 static void acpi_ec_clear(struct acpi_ec *ec)
834 {
835         int i, status;
836         u8 value = 0;
837 
838         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
839                 status = acpi_ec_query(ec, &value);
840                 if (status || !value)
841                         break;
842         }
843 
844         if (unlikely(i == ACPI_EC_CLEAR_MAX))
845                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
846         else
847                 pr_info("%d stale EC events cleared\n", i);
848 }
849 
850 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
851 {
852         unsigned long flags;
853 
854         spin_lock_irqsave(&ec->lock, flags);
855         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
856                 ec_dbg_drv("Starting EC");
857                 /* Enable GPE for event processing (SCI_EVT=1) */
858                 if (!resuming) {
859                         acpi_ec_submit_request(ec);
860                         ec_dbg_ref(ec, "Increase driver");
861                 }
862                 ec_log_drv("EC started");
863         }
864         spin_unlock_irqrestore(&ec->lock, flags);
865 }
866 
867 static bool acpi_ec_stopped(struct acpi_ec *ec)
868 {
869         unsigned long flags;
870         bool flushed;
871 
872         spin_lock_irqsave(&ec->lock, flags);
873         flushed = acpi_ec_flushed(ec);
874         spin_unlock_irqrestore(&ec->lock, flags);
875         return flushed;
876 }
877 
878 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
879 {
880         unsigned long flags;
881 
882         spin_lock_irqsave(&ec->lock, flags);
883         if (acpi_ec_started(ec)) {
884                 ec_dbg_drv("Stopping EC");
885                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
886                 spin_unlock_irqrestore(&ec->lock, flags);
887                 wait_event(ec->wait, acpi_ec_stopped(ec));
888                 spin_lock_irqsave(&ec->lock, flags);
889                 /* Disable GPE for event processing (SCI_EVT=1) */
890                 if (!suspending) {
891                         acpi_ec_complete_request(ec);
892                         ec_dbg_ref(ec, "Decrease driver");
893                 }
894                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
895                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
896                 ec_log_drv("EC stopped");
897         }
898         spin_unlock_irqrestore(&ec->lock, flags);
899 }
900 
901 void acpi_ec_block_transactions(void)
902 {
903         struct acpi_ec *ec = first_ec;
904 
905         if (!ec)
906                 return;
907 
908         mutex_lock(&ec->mutex);
909         /* Prevent transactions from being carried out */
910         acpi_ec_stop(ec, true);
911         mutex_unlock(&ec->mutex);
912 }
913 
914 void acpi_ec_unblock_transactions(void)
915 {
916         struct acpi_ec *ec = first_ec;
917 
918         if (!ec)
919                 return;
920 
921         /* Allow transactions to be carried out again */
922         acpi_ec_start(ec, true);
923 
924         if (EC_FLAGS_CLEAR_ON_RESUME)
925                 acpi_ec_clear(ec);
926 }
927 
928 void acpi_ec_unblock_transactions_early(void)
929 {
930         /*
931          * Allow transactions to happen again (this function is called from
932          * atomic context during wakeup, so we don't need to acquire the mutex).
933          */
934         if (first_ec)
935                 acpi_ec_start(first_ec, true);
936 }
937 
938 /* --------------------------------------------------------------------------
939                                 Event Management
940    -------------------------------------------------------------------------- */
941 static struct acpi_ec_query_handler *
942 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
943 {
944         if (handler)
945                 kref_get(&handler->kref);
946         return handler;
947 }
948 
949 static struct acpi_ec_query_handler *
950 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
951 {
952         struct acpi_ec_query_handler *handler;
953         bool found = false;
954 
955         mutex_lock(&ec->mutex);
956         list_for_each_entry(handler, &ec->list, node) {
957                 if (value == handler->query_bit) {
958                         found = true;
959                         break;
960                 }
961         }
962         mutex_unlock(&ec->mutex);
963         return found ? acpi_ec_get_query_handler(handler) : NULL;
964 }
965 
966 static void acpi_ec_query_handler_release(struct kref *kref)
967 {
968         struct acpi_ec_query_handler *handler =
969                 container_of(kref, struct acpi_ec_query_handler, kref);
970 
971         kfree(handler);
972 }
973 
974 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
975 {
976         kref_put(&handler->kref, acpi_ec_query_handler_release);
977 }
978 
979 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
980                               acpi_handle handle, acpi_ec_query_func func,
981                               void *data)
982 {
983         struct acpi_ec_query_handler *handler =
984             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
985 
986         if (!handler)
987                 return -ENOMEM;
988 
989         handler->query_bit = query_bit;
990         handler->handle = handle;
991         handler->func = func;
992         handler->data = data;
993         mutex_lock(&ec->mutex);
994         kref_init(&handler->kref);
995         list_add(&handler->node, &ec->list);
996         mutex_unlock(&ec->mutex);
997         return 0;
998 }
999 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1000 
1001 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1002                                           bool remove_all, u8 query_bit)
1003 {
1004         struct acpi_ec_query_handler *handler, *tmp;
1005         LIST_HEAD(free_list);
1006 
1007         mutex_lock(&ec->mutex);
1008         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1009                 if (remove_all || query_bit == handler->query_bit) {
1010                         list_del_init(&handler->node);
1011                         list_add(&handler->node, &free_list);
1012                 }
1013         }
1014         mutex_unlock(&ec->mutex);
1015         list_for_each_entry_safe(handler, tmp, &free_list, node)
1016                 acpi_ec_put_query_handler(handler);
1017 }
1018 
1019 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1020 {
1021         acpi_ec_remove_query_handlers(ec, false, query_bit);
1022 }
1023 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1024 
1025 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1026 {
1027         struct acpi_ec_query *q;
1028         struct transaction *t;
1029 
1030         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1031         if (!q)
1032                 return NULL;
1033         INIT_WORK(&q->work, acpi_ec_event_processor);
1034         t = &q->transaction;
1035         t->command = ACPI_EC_COMMAND_QUERY;
1036         t->rdata = pval;
1037         t->rlen = 1;
1038         return q;
1039 }
1040 
1041 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1042 {
1043         if (q) {
1044                 if (q->handler)
1045                         acpi_ec_put_query_handler(q->handler);
1046                 kfree(q);
1047         }
1048 }
1049 
1050 static void acpi_ec_event_processor(struct work_struct *work)
1051 {
1052         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1053         struct acpi_ec_query_handler *handler = q->handler;
1054 
1055         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1056         if (handler->func)
1057                 handler->func(handler->data);
1058         else if (handler->handle)
1059                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1060         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1061         acpi_ec_delete_query(q);
1062 }
1063 
1064 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1065 {
1066         u8 value = 0;
1067         int result;
1068         struct acpi_ec_query *q;
1069 
1070         q = acpi_ec_create_query(&value);
1071         if (!q)
1072                 return -ENOMEM;
1073 
1074         /*
1075          * Query the EC to find out which _Qxx method we need to evaluate.
1076          * Note that successful completion of the query causes the ACPI_EC_SCI
1077          * bit to be cleared (and thus clearing the interrupt source).
1078          */
1079         result = acpi_ec_transaction(ec, &q->transaction);
1080         if (!value)
1081                 result = -ENODATA;
1082         if (result)
1083                 goto err_exit;
1084 
1085         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1086         if (!q->handler) {
1087                 result = -ENODATA;
1088                 goto err_exit;
1089         }
1090 
1091         /*
1092          * It is reported that _Qxx are evaluated in a parallel way on
1093          * Windows:
1094          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1095          *
1096          * Put this log entry before schedule_work() in order to make
1097          * it appearing before any other log entries occurred during the
1098          * work queue execution.
1099          */
1100         ec_dbg_evt("Query(0x%02x) scheduled", value);
1101         if (!schedule_work(&q->work)) {
1102                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1103                 result = -EBUSY;
1104         }
1105 
1106 err_exit:
1107         if (result)
1108                 acpi_ec_delete_query(q);
1109         if (data)
1110                 *data = value;
1111         return result;
1112 }
1113 
1114 static void acpi_ec_check_event(struct acpi_ec *ec)
1115 {
1116         unsigned long flags;
1117 
1118         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1119                 if (ec_guard(ec)) {
1120                         spin_lock_irqsave(&ec->lock, flags);
1121                         /*
1122                          * Take care of the SCI_EVT unless no one else is
1123                          * taking care of it.
1124                          */
1125                         if (!ec->curr)
1126                                 advance_transaction(ec);
1127                         spin_unlock_irqrestore(&ec->lock, flags);
1128                 }
1129         }
1130 }
1131 
1132 static void acpi_ec_event_handler(struct work_struct *work)
1133 {
1134         unsigned long flags;
1135         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1136 
1137         ec_dbg_evt("Event started");
1138 
1139         spin_lock_irqsave(&ec->lock, flags);
1140         while (ec->nr_pending_queries) {
1141                 spin_unlock_irqrestore(&ec->lock, flags);
1142                 (void)acpi_ec_query(ec, NULL);
1143                 spin_lock_irqsave(&ec->lock, flags);
1144                 ec->nr_pending_queries--;
1145                 /*
1146                  * Before exit, make sure that this work item can be
1147                  * scheduled again. There might be QR_EC failures, leaving
1148                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1149                  * item from being scheduled again.
1150                  */
1151                 if (!ec->nr_pending_queries) {
1152                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1153                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1154                                 acpi_ec_complete_query(ec);
1155                 }
1156         }
1157         spin_unlock_irqrestore(&ec->lock, flags);
1158 
1159         ec_dbg_evt("Event stopped");
1160 
1161         acpi_ec_check_event(ec);
1162 }
1163 
1164 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1165         u32 gpe_number, void *data)
1166 {
1167         unsigned long flags;
1168         struct acpi_ec *ec = data;
1169 
1170         spin_lock_irqsave(&ec->lock, flags);
1171         advance_transaction(ec);
1172         spin_unlock_irqrestore(&ec->lock, flags);
1173         return ACPI_INTERRUPT_HANDLED;
1174 }
1175 
1176 /* --------------------------------------------------------------------------
1177  *                           Address Space Management
1178  * -------------------------------------------------------------------------- */
1179 
1180 static acpi_status
1181 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1182                       u32 bits, u64 *value64,
1183                       void *handler_context, void *region_context)
1184 {
1185         struct acpi_ec *ec = handler_context;
1186         int result = 0, i, bytes = bits / 8;
1187         u8 *value = (u8 *)value64;
1188 
1189         if ((address > 0xFF) || !value || !handler_context)
1190                 return AE_BAD_PARAMETER;
1191 
1192         if (function != ACPI_READ && function != ACPI_WRITE)
1193                 return AE_BAD_PARAMETER;
1194 
1195         if (ec_busy_polling || bits > 8)
1196                 acpi_ec_burst_enable(ec);
1197 
1198         for (i = 0; i < bytes; ++i, ++address, ++value)
1199                 result = (function == ACPI_READ) ?
1200                         acpi_ec_read(ec, address, value) :
1201                         acpi_ec_write(ec, address, *value);
1202 
1203         if (ec_busy_polling || bits > 8)
1204                 acpi_ec_burst_disable(ec);
1205 
1206         switch (result) {
1207         case -EINVAL:
1208                 return AE_BAD_PARAMETER;
1209         case -ENODEV:
1210                 return AE_NOT_FOUND;
1211         case -ETIME:
1212                 return AE_TIME;
1213         default:
1214                 return AE_OK;
1215         }
1216 }
1217 
1218 /* --------------------------------------------------------------------------
1219  *                             Driver Interface
1220  * -------------------------------------------------------------------------- */
1221 
1222 static acpi_status
1223 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1224 
1225 static struct acpi_ec *make_acpi_ec(void)
1226 {
1227         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1228 
1229         if (!ec)
1230                 return NULL;
1231         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1232         mutex_init(&ec->mutex);
1233         init_waitqueue_head(&ec->wait);
1234         INIT_LIST_HEAD(&ec->list);
1235         spin_lock_init(&ec->lock);
1236         INIT_WORK(&ec->work, acpi_ec_event_handler);
1237         ec->timestamp = jiffies;
1238         return ec;
1239 }
1240 
1241 static acpi_status
1242 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1243                                void *context, void **return_value)
1244 {
1245         char node_name[5];
1246         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1247         struct acpi_ec *ec = context;
1248         int value = 0;
1249         acpi_status status;
1250 
1251         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1252 
1253         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1254                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1255         return AE_OK;
1256 }
1257 
1258 static acpi_status
1259 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1260 {
1261         acpi_status status;
1262         unsigned long long tmp = 0;
1263         struct acpi_ec *ec = context;
1264 
1265         /* clear addr values, ec_parse_io_ports depend on it */
1266         ec->command_addr = ec->data_addr = 0;
1267 
1268         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1269                                      ec_parse_io_ports, ec);
1270         if (ACPI_FAILURE(status))
1271                 return status;
1272 
1273         /* Get GPE bit assignment (EC events). */
1274         /* TODO: Add support for _GPE returning a package */
1275         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1276         if (ACPI_FAILURE(status))
1277                 return status;
1278         ec->gpe = tmp;
1279         /* Use the global lock for all EC transactions? */
1280         tmp = 0;
1281         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1282         ec->global_lock = tmp;
1283         ec->handle = handle;
1284         return AE_CTRL_TERMINATE;
1285 }
1286 
1287 static int ec_install_handlers(struct acpi_ec *ec)
1288 {
1289         acpi_status status;
1290 
1291         acpi_ec_start(ec, false);
1292 
1293         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1294                 status = acpi_install_address_space_handler(ec->handle,
1295                                                             ACPI_ADR_SPACE_EC,
1296                                                             &acpi_ec_space_handler,
1297                                                             NULL, ec);
1298                 if (ACPI_FAILURE(status)) {
1299                         if (status == AE_NOT_FOUND) {
1300                                 /*
1301                                  * Maybe OS fails in evaluating the _REG
1302                                  * object. The AE_NOT_FOUND error will be
1303                                  * ignored and OS * continue to initialize
1304                                  * EC.
1305                                  */
1306                                 pr_err("Fail in evaluating the _REG object"
1307                                         " of EC device. Broken bios is suspected.\n");
1308                         } else {
1309                                 acpi_ec_stop(ec, false);
1310                                 return -ENODEV;
1311                         }
1312                 }
1313                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1314         }
1315 
1316         if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1317                 status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1318                                           ACPI_GPE_EDGE_TRIGGERED,
1319                                           &acpi_ec_gpe_handler, ec);
1320                 /* This is not fatal as we can poll EC events */
1321                 if (ACPI_SUCCESS(status)) {
1322                         set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1323                         if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1324                             ec->reference_count >= 1)
1325                                 acpi_ec_enable_gpe(ec, true);
1326                 }
1327         }
1328 
1329         return 0;
1330 }
1331 
1332 static void ec_remove_handlers(struct acpi_ec *ec)
1333 {
1334         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1335                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1336                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1337                         pr_err("failed to remove space handler\n");
1338                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1339         }
1340 
1341         /*
1342          * Stops handling the EC transactions after removing the operation
1343          * region handler. This is required because _REG(DISCONNECT)
1344          * invoked during the removal can result in new EC transactions.
1345          *
1346          * Flushes the EC requests and thus disables the GPE before
1347          * removing the GPE handler. This is required by the current ACPICA
1348          * GPE core. ACPICA GPE core will automatically disable a GPE when
1349          * it is indicated but there is no way to handle it. So the drivers
1350          * must disable the GPEs prior to removing the GPE handlers.
1351          */
1352         acpi_ec_stop(ec, false);
1353 
1354         if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1355                 if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1356                                         &acpi_ec_gpe_handler)))
1357                         pr_err("failed to remove gpe handler\n");
1358                 clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1359         }
1360 }
1361 
1362 static int acpi_ec_add(struct acpi_device *device)
1363 {
1364         struct acpi_ec *ec = NULL;
1365         int ret;
1366 
1367         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1368         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1369 
1370         /* Check for boot EC */
1371         if (boot_ec) {
1372                 ec = boot_ec;
1373                 boot_ec = NULL;
1374                 ec_remove_handlers(ec);
1375                 if (first_ec == ec)
1376                         first_ec = NULL;
1377         } else {
1378                 ec = make_acpi_ec();
1379                 if (!ec)
1380                         return -ENOMEM;
1381         }
1382         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1383                 AE_CTRL_TERMINATE) {
1384                         kfree(ec);
1385                         return -EINVAL;
1386         }
1387 
1388         /* Find and register all query methods */
1389         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1390                             acpi_ec_register_query_methods, NULL, ec, NULL);
1391 
1392         if (!first_ec)
1393                 first_ec = ec;
1394         device->driver_data = ec;
1395 
1396         ret = !!request_region(ec->data_addr, 1, "EC data");
1397         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1398         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1399         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1400 
1401         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1402                           ec->gpe, ec->command_addr, ec->data_addr);
1403 
1404         ret = ec_install_handlers(ec);
1405 
1406         /* Reprobe devices depending on the EC */
1407         acpi_walk_dep_device_list(ec->handle);
1408 
1409         /* EC is fully operational, allow queries */
1410         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1411 
1412         /* Clear stale _Q events if hardware might require that */
1413         if (EC_FLAGS_CLEAR_ON_RESUME)
1414                 acpi_ec_clear(ec);
1415         return ret;
1416 }
1417 
1418 static int acpi_ec_remove(struct acpi_device *device)
1419 {
1420         struct acpi_ec *ec;
1421 
1422         if (!device)
1423                 return -EINVAL;
1424 
1425         ec = acpi_driver_data(device);
1426         ec_remove_handlers(ec);
1427         acpi_ec_remove_query_handlers(ec, true, 0);
1428         release_region(ec->data_addr, 1);
1429         release_region(ec->command_addr, 1);
1430         device->driver_data = NULL;
1431         if (ec == first_ec)
1432                 first_ec = NULL;
1433         kfree(ec);
1434         return 0;
1435 }
1436 
1437 static acpi_status
1438 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1439 {
1440         struct acpi_ec *ec = context;
1441 
1442         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1443                 return AE_OK;
1444 
1445         /*
1446          * The first address region returned is the data port, and
1447          * the second address region returned is the status/command
1448          * port.
1449          */
1450         if (ec->data_addr == 0)
1451                 ec->data_addr = resource->data.io.minimum;
1452         else if (ec->command_addr == 0)
1453                 ec->command_addr = resource->data.io.minimum;
1454         else
1455                 return AE_CTRL_TERMINATE;
1456 
1457         return AE_OK;
1458 }
1459 
1460 static const struct acpi_device_id ec_device_ids[] = {
1461         {"PNP0C09", 0},
1462         {"", 0},
1463 };
1464 
1465 int __init acpi_ec_dsdt_probe(void)
1466 {
1467         acpi_status status;
1468 
1469         if (boot_ec)
1470                 return 0;
1471 
1472         /*
1473          * Finding EC from DSDT if there is no ECDT EC available. When this
1474          * function is invoked, ACPI tables have been fully loaded, we can
1475          * walk namespace now.
1476          */
1477         boot_ec = make_acpi_ec();
1478         if (!boot_ec)
1479                 return -ENOMEM;
1480         status = acpi_get_devices(ec_device_ids[0].id,
1481                                   ec_parse_device, boot_ec, NULL);
1482         if (ACPI_FAILURE(status) || !boot_ec->handle)
1483                 return -ENODEV;
1484         if (!ec_install_handlers(boot_ec)) {
1485                 first_ec = boot_ec;
1486                 return 0;
1487         }
1488         return -EFAULT;
1489 }
1490 
1491 #if 0
1492 /*
1493  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1494  * set, for which case, we complete the QR_EC without issuing it to the
1495  * firmware.
1496  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1497  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1498  */
1499 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1500 {
1501         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1502         EC_FLAGS_QUERY_HANDSHAKE = 1;
1503         return 0;
1504 }
1505 #endif
1506 
1507 /*
1508  * On some hardware it is necessary to clear events accumulated by the EC during
1509  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1510  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1511  *
1512  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1513  *
1514  * Ideally, the EC should also be instructed NOT to accumulate events during
1515  * sleep (which Windows seems to do somehow), but the interface to control this
1516  * behaviour is not known at this time.
1517  *
1518  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1519  * however it is very likely that other Samsung models are affected.
1520  *
1521  * On systems which don't accumulate _Q events during sleep, this extra check
1522  * should be harmless.
1523  */
1524 static int ec_clear_on_resume(const struct dmi_system_id *id)
1525 {
1526         pr_debug("Detected system needing EC poll on resume.\n");
1527         EC_FLAGS_CLEAR_ON_RESUME = 1;
1528         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1529         return 0;
1530 }
1531 
1532 static int ec_correct_ecdt(const struct dmi_system_id *id)
1533 {
1534         pr_debug("Detected system needing ECDT address correction.\n");
1535         EC_FLAGS_CORRECT_ECDT = 1;
1536         return 0;
1537 }
1538 
1539 static struct dmi_system_id ec_dmi_table[] __initdata = {
1540         {
1541         ec_correct_ecdt, "Asus L4R", {
1542         DMI_MATCH(DMI_BIOS_VERSION, "1008.006"),
1543         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),
1544         DMI_MATCH(DMI_BOARD_NAME, "L4R") }, NULL},
1545         {
1546         ec_correct_ecdt, "Asus M6R", {
1547         DMI_MATCH(DMI_BIOS_VERSION, "0207"),
1548         DMI_MATCH(DMI_PRODUCT_NAME, "M6R"),
1549         DMI_MATCH(DMI_BOARD_NAME, "M6R") }, NULL},
1550         {
1551         ec_correct_ecdt, "MSI MS-171F", {
1552         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1553         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1554         {
1555         ec_clear_on_resume, "Samsung hardware", {
1556         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1557         {},
1558 };
1559 
1560 int __init acpi_ec_ecdt_probe(void)
1561 {
1562         int ret = 0;
1563         acpi_status status;
1564         struct acpi_table_ecdt *ecdt_ptr;
1565 
1566         boot_ec = make_acpi_ec();
1567         if (!boot_ec)
1568                 return -ENOMEM;
1569         /*
1570          * Generate a boot ec context
1571          */
1572         dmi_check_system(ec_dmi_table);
1573         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1574                                 (struct acpi_table_header **)&ecdt_ptr);
1575         if (ACPI_FAILURE(status)) {
1576                 ret = -ENODEV;
1577                 goto error;
1578         }
1579 
1580         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1581                 /*
1582                  * Asus X50GL:
1583                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1584                  */
1585                 ret = -ENODEV;
1586                 goto error;
1587         }
1588 
1589         pr_info("EC description table is found, configuring boot EC\n");
1590         if (EC_FLAGS_CORRECT_ECDT) {
1591                 /*
1592                  * Asus L4R, Asus M6R
1593                  * https://bugzilla.kernel.org/show_bug.cgi?id=9399
1594                  * MSI MS-171F
1595                  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1596                  */
1597                 boot_ec->command_addr = ecdt_ptr->data.address;
1598                 boot_ec->data_addr = ecdt_ptr->control.address;
1599         } else {
1600                 boot_ec->command_addr = ecdt_ptr->control.address;
1601                 boot_ec->data_addr = ecdt_ptr->data.address;
1602         }
1603         boot_ec->gpe = ecdt_ptr->gpe;
1604         boot_ec->handle = ACPI_ROOT_OBJECT;
1605         ret = ec_install_handlers(boot_ec);
1606         if (!ret)
1607                 first_ec = boot_ec;
1608 error:
1609         if (ret) {
1610                 kfree(boot_ec);
1611                 boot_ec = NULL;
1612         }
1613         return ret;
1614 }
1615 
1616 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1617 {
1618         int result = 0;
1619 
1620         if (!strncmp(val, "status", sizeof("status") - 1)) {
1621                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1622                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1623         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1624                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1625                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1626         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1627                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1628                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1629         } else
1630                 result = -EINVAL;
1631         return result;
1632 }
1633 
1634 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1635 {
1636         switch (ec_event_clearing) {
1637         case ACPI_EC_EVT_TIMING_STATUS:
1638                 return sprintf(buffer, "status");
1639         case ACPI_EC_EVT_TIMING_QUERY:
1640                 return sprintf(buffer, "query");
1641         case ACPI_EC_EVT_TIMING_EVENT:
1642                 return sprintf(buffer, "event");
1643         default:
1644                 return sprintf(buffer, "invalid");
1645         }
1646         return 0;
1647 }
1648 
1649 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1650                   NULL, 0644);
1651 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1652 
1653 static struct acpi_driver acpi_ec_driver = {
1654         .name = "ec",
1655         .class = ACPI_EC_CLASS,
1656         .ids = ec_device_ids,
1657         .ops = {
1658                 .add = acpi_ec_add,
1659                 .remove = acpi_ec_remove,
1660                 },
1661 };
1662 
1663 int __init acpi_ec_init(void)
1664 {
1665         int result = 0;
1666 
1667         /* Now register the driver for the EC */
1668         result = acpi_bus_register_driver(&acpi_ec_driver);
1669         if (result < 0)
1670                 return -ENODEV;
1671 
1672         return result;
1673 }
1674 
1675 /* EC driver currently not unloadable */
1676 #if 0
1677 static void __exit acpi_ec_exit(void)
1678 {
1679 
1680         acpi_bus_unregister_driver(&acpi_ec_driver);
1681 }
1682 #endif  /* 0 */
1683 

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