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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  *  You should have received a copy of the GNU General Public License along
 26  *  with this program; if not, write to the Free Software Foundation, Inc.,
 27  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 28  *
 29  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 30  */
 31 
 32 /* Uncomment next line to get verbose printout */
 33 /* #define DEBUG */
 34 #define pr_fmt(fmt) "ACPI : EC: " fmt
 35 
 36 #include <linux/kernel.h>
 37 #include <linux/module.h>
 38 #include <linux/init.h>
 39 #include <linux/types.h>
 40 #include <linux/delay.h>
 41 #include <linux/interrupt.h>
 42 #include <linux/list.h>
 43 #include <linux/spinlock.h>
 44 #include <linux/slab.h>
 45 #include <linux/acpi.h>
 46 #include <linux/dmi.h>
 47 #include <asm/io.h>
 48 
 49 #include "internal.h"
 50 
 51 #define ACPI_EC_CLASS                   "embedded_controller"
 52 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
 53 #define ACPI_EC_FILE_INFO               "info"
 54 
 55 /* EC status register */
 56 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
 57 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
 58 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
 59 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
 60 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
 61 
 62 /*
 63  * The SCI_EVT clearing timing is not defined by the ACPI specification.
 64  * This leads to lots of practical timing issues for the host EC driver.
 65  * The following variations are defined (from the target EC firmware's
 66  * perspective):
 67  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
 68  *         target can clear SCI_EVT at any time so long as the host can see
 69  *         the indication by reading the status register (EC_SC). So the
 70  *         host should re-check SCI_EVT after the first time the SCI_EVT
 71  *         indication is seen, which is the same time the query request
 72  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
 73  *         at any later time could indicate another event. Normally such
 74  *         kind of EC firmware has implemented an event queue and will
 75  *         return 0x00 to indicate "no outstanding event".
 76  * QUERY: After seeing the query request (QR_EC) written to the command
 77  *        register (EC_CMD) by the host and having prepared the responding
 78  *        event value in the data register (EC_DATA), the target can safely
 79  *        clear SCI_EVT because the target can confirm that the current
 80  *        event is being handled by the host. The host then should check
 81  *        SCI_EVT right after reading the event response from the data
 82  *        register (EC_DATA).
 83  * EVENT: After seeing the event response read from the data register
 84  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
 85  *        target requires time to notice the change in the data register
 86  *        (EC_DATA), the host may be required to wait additional guarding
 87  *        time before checking the SCI_EVT again. Such guarding may not be
 88  *        necessary if the host is notified via another IRQ.
 89  */
 90 #define ACPI_EC_EVT_TIMING_STATUS       0x00
 91 #define ACPI_EC_EVT_TIMING_QUERY        0x01
 92 #define ACPI_EC_EVT_TIMING_EVENT        0x02
 93 
 94 /* EC commands */
 95 enum ec_command {
 96         ACPI_EC_COMMAND_READ = 0x80,
 97         ACPI_EC_COMMAND_WRITE = 0x81,
 98         ACPI_EC_BURST_ENABLE = 0x82,
 99         ACPI_EC_BURST_DISABLE = 0x83,
100         ACPI_EC_COMMAND_QUERY = 0x84,
101 };
102 
103 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
104 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
105 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
106 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
107                                          * when trying to clear the EC */
108 
109 enum {
110         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
111         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
112         EC_FLAGS_HANDLERS_INSTALLED,    /* Handlers for GPE and
113                                          * OpReg are installed */
114         EC_FLAGS_STARTED,               /* Driver is started */
115         EC_FLAGS_STOPPED,               /* Driver is stopped */
116         EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
117                                          * current command processing */
118 };
119 
120 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
121 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
122 
123 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
124 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
125 module_param(ec_delay, uint, 0644);
126 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
127 
128 static bool ec_busy_polling __read_mostly;
129 module_param(ec_busy_polling, bool, 0644);
130 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
131 
132 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
133 module_param(ec_polling_guard, uint, 0644);
134 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
135 
136 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
137 
138 /*
139  * If the number of false interrupts per one transaction exceeds
140  * this threshold, will think there is a GPE storm happened and
141  * will disable the GPE for normal transaction.
142  */
143 static unsigned int ec_storm_threshold  __read_mostly = 8;
144 module_param(ec_storm_threshold, uint, 0644);
145 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
146 
147 struct acpi_ec_query_handler {
148         struct list_head node;
149         acpi_ec_query_func func;
150         acpi_handle handle;
151         void *data;
152         u8 query_bit;
153         struct kref kref;
154 };
155 
156 struct transaction {
157         const u8 *wdata;
158         u8 *rdata;
159         unsigned short irq_count;
160         u8 command;
161         u8 wi;
162         u8 ri;
163         u8 wlen;
164         u8 rlen;
165         u8 flags;
166 };
167 
168 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
169 static void advance_transaction(struct acpi_ec *ec);
170 
171 struct acpi_ec *boot_ec, *first_ec;
172 EXPORT_SYMBOL(first_ec);
173 
174 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
175 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
176 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
177 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
178 
179 /* --------------------------------------------------------------------------
180  *                           Logging/Debugging
181  * -------------------------------------------------------------------------- */
182 
183 /*
184  * Splitters used by the developers to track the boundary of the EC
185  * handling processes.
186  */
187 #ifdef DEBUG
188 #define EC_DBG_SEP      " "
189 #define EC_DBG_DRV      "+++++"
190 #define EC_DBG_STM      "====="
191 #define EC_DBG_REQ      "*****"
192 #define EC_DBG_EVT      "#####"
193 #else
194 #define EC_DBG_SEP      ""
195 #define EC_DBG_DRV
196 #define EC_DBG_STM
197 #define EC_DBG_REQ
198 #define EC_DBG_EVT
199 #endif
200 
201 #define ec_log_raw(fmt, ...) \
202         pr_info(fmt "\n", ##__VA_ARGS__)
203 #define ec_dbg_raw(fmt, ...) \
204         pr_debug(fmt "\n", ##__VA_ARGS__)
205 #define ec_log(filter, fmt, ...) \
206         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
207 #define ec_dbg(filter, fmt, ...) \
208         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
209 
210 #define ec_log_drv(fmt, ...) \
211         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
212 #define ec_dbg_drv(fmt, ...) \
213         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
214 #define ec_dbg_stm(fmt, ...) \
215         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
216 #define ec_dbg_req(fmt, ...) \
217         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
218 #define ec_dbg_evt(fmt, ...) \
219         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
220 #define ec_dbg_ref(ec, fmt, ...) \
221         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
222 
223 /* --------------------------------------------------------------------------
224  *                           Device Flags
225  * -------------------------------------------------------------------------- */
226 
227 static bool acpi_ec_started(struct acpi_ec *ec)
228 {
229         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
230                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
231 }
232 
233 static bool acpi_ec_flushed(struct acpi_ec *ec)
234 {
235         return ec->reference_count == 1;
236 }
237 
238 /* --------------------------------------------------------------------------
239  *                           EC Registers
240  * -------------------------------------------------------------------------- */
241 
242 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
243 {
244         u8 x = inb(ec->command_addr);
245 
246         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
247                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
248                    x,
249                    !!(x & ACPI_EC_FLAG_SCI),
250                    !!(x & ACPI_EC_FLAG_BURST),
251                    !!(x & ACPI_EC_FLAG_CMD),
252                    !!(x & ACPI_EC_FLAG_IBF),
253                    !!(x & ACPI_EC_FLAG_OBF));
254         return x;
255 }
256 
257 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
258 {
259         u8 x = inb(ec->data_addr);
260 
261         ec->timestamp = jiffies;
262         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
263         return x;
264 }
265 
266 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
267 {
268         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
269         outb(command, ec->command_addr);
270         ec->timestamp = jiffies;
271 }
272 
273 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
274 {
275         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
276         outb(data, ec->data_addr);
277         ec->timestamp = jiffies;
278 }
279 
280 #ifdef DEBUG
281 static const char *acpi_ec_cmd_string(u8 cmd)
282 {
283         switch (cmd) {
284         case 0x80:
285                 return "RD_EC";
286         case 0x81:
287                 return "WR_EC";
288         case 0x82:
289                 return "BE_EC";
290         case 0x83:
291                 return "BD_EC";
292         case 0x84:
293                 return "QR_EC";
294         }
295         return "UNKNOWN";
296 }
297 #else
298 #define acpi_ec_cmd_string(cmd)         "UNDEF"
299 #endif
300 
301 /* --------------------------------------------------------------------------
302  *                           GPE Registers
303  * -------------------------------------------------------------------------- */
304 
305 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
306 {
307         acpi_event_status gpe_status = 0;
308 
309         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
310         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
311 }
312 
313 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
314 {
315         if (open)
316                 acpi_enable_gpe(NULL, ec->gpe);
317         else {
318                 BUG_ON(ec->reference_count < 1);
319                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
320         }
321         if (acpi_ec_is_gpe_raised(ec)) {
322                 /*
323                  * On some platforms, EN=1 writes cannot trigger GPE. So
324                  * software need to manually trigger a pseudo GPE event on
325                  * EN=1 writes.
326                  */
327                 ec_dbg_raw("Polling quirk");
328                 advance_transaction(ec);
329         }
330 }
331 
332 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
333 {
334         if (close)
335                 acpi_disable_gpe(NULL, ec->gpe);
336         else {
337                 BUG_ON(ec->reference_count < 1);
338                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
339         }
340 }
341 
342 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
343 {
344         /*
345          * GPE STS is a W1C register, which means:
346          * 1. Software can clear it without worrying about clearing other
347          *    GPEs' STS bits when the hardware sets them in parallel.
348          * 2. As long as software can ensure only clearing it when it is
349          *    set, hardware won't set it in parallel.
350          * So software can clear GPE in any contexts.
351          * Warning: do not move the check into advance_transaction() as the
352          * EC commands will be sent without GPE raised.
353          */
354         if (!acpi_ec_is_gpe_raised(ec))
355                 return;
356         acpi_clear_gpe(NULL, ec->gpe);
357 }
358 
359 /* --------------------------------------------------------------------------
360  *                           Transaction Management
361  * -------------------------------------------------------------------------- */
362 
363 static void acpi_ec_submit_request(struct acpi_ec *ec)
364 {
365         ec->reference_count++;
366         if (ec->reference_count == 1)
367                 acpi_ec_enable_gpe(ec, true);
368 }
369 
370 static void acpi_ec_complete_request(struct acpi_ec *ec)
371 {
372         bool flushed = false;
373 
374         ec->reference_count--;
375         if (ec->reference_count == 0)
376                 acpi_ec_disable_gpe(ec, true);
377         flushed = acpi_ec_flushed(ec);
378         if (flushed)
379                 wake_up(&ec->wait);
380 }
381 
382 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
383 {
384         if (!test_bit(flag, &ec->flags)) {
385                 acpi_ec_disable_gpe(ec, false);
386                 ec_dbg_drv("Polling enabled");
387                 set_bit(flag, &ec->flags);
388         }
389 }
390 
391 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
392 {
393         if (test_bit(flag, &ec->flags)) {
394                 clear_bit(flag, &ec->flags);
395                 acpi_ec_enable_gpe(ec, false);
396                 ec_dbg_drv("Polling disabled");
397         }
398 }
399 
400 /*
401  * acpi_ec_submit_flushable_request() - Increase the reference count unless
402  *                                      the flush operation is not in
403  *                                      progress
404  * @ec: the EC device
405  *
406  * This function must be used before taking a new action that should hold
407  * the reference count.  If this function returns false, then the action
408  * must be discarded or it will prevent the flush operation from being
409  * completed.
410  */
411 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
412 {
413         if (!acpi_ec_started(ec))
414                 return false;
415         acpi_ec_submit_request(ec);
416         return true;
417 }
418 
419 static void acpi_ec_submit_query(struct acpi_ec *ec)
420 {
421         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
422                 ec_dbg_evt("Command(%s) submitted/blocked",
423                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
424                 ec->nr_pending_queries++;
425                 schedule_work(&ec->work);
426         }
427 }
428 
429 static void acpi_ec_complete_query(struct acpi_ec *ec)
430 {
431         if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
432                 clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
433                 ec_dbg_evt("Command(%s) unblocked",
434                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
435         }
436 }
437 
438 static bool acpi_ec_guard_event(struct acpi_ec *ec)
439 {
440         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
441             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
442             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
443             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
444                 return false;
445 
446         /*
447          * Postpone the query submission to allow the firmware to proceed,
448          * we shouldn't check SCI_EVT before the firmware reflagging it.
449          */
450         return true;
451 }
452 
453 static int ec_transaction_polled(struct acpi_ec *ec)
454 {
455         unsigned long flags;
456         int ret = 0;
457 
458         spin_lock_irqsave(&ec->lock, flags);
459         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
460                 ret = 1;
461         spin_unlock_irqrestore(&ec->lock, flags);
462         return ret;
463 }
464 
465 static int ec_transaction_completed(struct acpi_ec *ec)
466 {
467         unsigned long flags;
468         int ret = 0;
469 
470         spin_lock_irqsave(&ec->lock, flags);
471         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
472                 ret = 1;
473         spin_unlock_irqrestore(&ec->lock, flags);
474         return ret;
475 }
476 
477 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
478 {
479         ec->curr->flags |= flag;
480         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
481                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
482                     flag == ACPI_EC_COMMAND_POLL)
483                         acpi_ec_complete_query(ec);
484                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
485                     flag == ACPI_EC_COMMAND_COMPLETE)
486                         acpi_ec_complete_query(ec);
487                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
488                     flag == ACPI_EC_COMMAND_COMPLETE)
489                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
490         }
491 }
492 
493 static void advance_transaction(struct acpi_ec *ec)
494 {
495         struct transaction *t;
496         u8 status;
497         bool wakeup = false;
498 
499         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
500                    smp_processor_id());
501         /*
502          * By always clearing STS before handling all indications, we can
503          * ensure a hardware STS 0->1 change after this clearing can always
504          * trigger a GPE interrupt.
505          */
506         acpi_ec_clear_gpe(ec);
507         status = acpi_ec_read_status(ec);
508         t = ec->curr;
509         /*
510          * Another IRQ or a guarded polling mode advancement is detected,
511          * the next QR_EC submission is then allowed.
512          */
513         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
514                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
515                     (!ec->nr_pending_queries ||
516                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
517                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
518                         acpi_ec_complete_query(ec);
519                 }
520         }
521         if (!t)
522                 goto err;
523         if (t->flags & ACPI_EC_COMMAND_POLL) {
524                 if (t->wlen > t->wi) {
525                         if ((status & ACPI_EC_FLAG_IBF) == 0)
526                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
527                         else
528                                 goto err;
529                 } else if (t->rlen > t->ri) {
530                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
531                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
532                                 if (t->rlen == t->ri) {
533                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
534                                         if (t->command == ACPI_EC_COMMAND_QUERY)
535                                                 ec_dbg_evt("Command(%s) completed by hardware",
536                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
537                                         wakeup = true;
538                                 }
539                         } else
540                                 goto err;
541                 } else if (t->wlen == t->wi &&
542                            (status & ACPI_EC_FLAG_IBF) == 0) {
543                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
544                         wakeup = true;
545                 }
546                 goto out;
547         } else {
548                 if (EC_FLAGS_QUERY_HANDSHAKE &&
549                     !(status & ACPI_EC_FLAG_SCI) &&
550                     (t->command == ACPI_EC_COMMAND_QUERY)) {
551                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
552                         t->rdata[t->ri++] = 0x00;
553                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
554                         ec_dbg_evt("Command(%s) completed by software",
555                                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
556                         wakeup = true;
557                 } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
558                         acpi_ec_write_cmd(ec, t->command);
559                         ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
560                 } else
561                         goto err;
562                 goto out;
563         }
564 err:
565         /*
566          * If SCI bit is set, then don't think it's a false IRQ
567          * otherwise will take a not handled IRQ as a false one.
568          */
569         if (!(status & ACPI_EC_FLAG_SCI)) {
570                 if (in_interrupt() && t) {
571                         if (t->irq_count < ec_storm_threshold)
572                                 ++t->irq_count;
573                         /* Allow triggering on 0 threshold */
574                         if (t->irq_count == ec_storm_threshold)
575                                 acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
576                 }
577         }
578 out:
579         if (status & ACPI_EC_FLAG_SCI)
580                 acpi_ec_submit_query(ec);
581         if (wakeup && in_interrupt())
582                 wake_up(&ec->wait);
583 }
584 
585 static void start_transaction(struct acpi_ec *ec)
586 {
587         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
588         ec->curr->flags = 0;
589 }
590 
591 static int ec_guard(struct acpi_ec *ec)
592 {
593         unsigned long guard = usecs_to_jiffies(ec_polling_guard);
594         unsigned long timeout = ec->timestamp + guard;
595 
596         do {
597                 if (ec_busy_polling) {
598                         /* Perform busy polling */
599                         if (ec_transaction_completed(ec))
600                                 return 0;
601                         udelay(jiffies_to_usecs(guard));
602                 } else {
603                         /*
604                          * Perform wait polling
605                          *
606                          * For SCI_EVT clearing timing of "event",
607                          * performing guarding before re-checking the
608                          * SCI_EVT. Otherwise, such guarding is not needed
609                          * due to the old practices.
610                          */
611                         if (!ec_transaction_polled(ec) &&
612                             !acpi_ec_guard_event(ec))
613                                 break;
614                         if (wait_event_timeout(ec->wait,
615                                                ec_transaction_completed(ec),
616                                                guard))
617                                 return 0;
618                 }
619                 /* Guard the register accesses for the polling modes */
620         } while (time_before(jiffies, timeout));
621         return -ETIME;
622 }
623 
624 static int ec_poll(struct acpi_ec *ec)
625 {
626         unsigned long flags;
627         int repeat = 5; /* number of command restarts */
628 
629         while (repeat--) {
630                 unsigned long delay = jiffies +
631                         msecs_to_jiffies(ec_delay);
632                 do {
633                         if (!ec_guard(ec))
634                                 return 0;
635                         spin_lock_irqsave(&ec->lock, flags);
636                         advance_transaction(ec);
637                         spin_unlock_irqrestore(&ec->lock, flags);
638                 } while (time_before(jiffies, delay));
639                 pr_debug("controller reset, restart transaction\n");
640                 spin_lock_irqsave(&ec->lock, flags);
641                 start_transaction(ec);
642                 spin_unlock_irqrestore(&ec->lock, flags);
643         }
644         return -ETIME;
645 }
646 
647 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
648                                         struct transaction *t)
649 {
650         unsigned long tmp;
651         int ret = 0;
652 
653         /* start transaction */
654         spin_lock_irqsave(&ec->lock, tmp);
655         /* Enable GPE for command processing (IBF=0/OBF=1) */
656         if (!acpi_ec_submit_flushable_request(ec)) {
657                 ret = -EINVAL;
658                 goto unlock;
659         }
660         ec_dbg_ref(ec, "Increase command");
661         /* following two actions should be kept atomic */
662         ec->curr = t;
663         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
664         start_transaction(ec);
665         spin_unlock_irqrestore(&ec->lock, tmp);
666 
667         ret = ec_poll(ec);
668 
669         spin_lock_irqsave(&ec->lock, tmp);
670         if (t->irq_count == ec_storm_threshold)
671                 acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
672         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
673         ec->curr = NULL;
674         /* Disable GPE for command processing (IBF=0/OBF=1) */
675         acpi_ec_complete_request(ec);
676         ec_dbg_ref(ec, "Decrease command");
677 unlock:
678         spin_unlock_irqrestore(&ec->lock, tmp);
679         return ret;
680 }
681 
682 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
683 {
684         int status;
685         u32 glk;
686 
687         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
688                 return -EINVAL;
689         if (t->rdata)
690                 memset(t->rdata, 0, t->rlen);
691 
692         mutex_lock(&ec->mutex);
693         if (ec->global_lock) {
694                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
695                 if (ACPI_FAILURE(status)) {
696                         status = -ENODEV;
697                         goto unlock;
698                 }
699         }
700 
701         status = acpi_ec_transaction_unlocked(ec, t);
702 
703         if (ec->global_lock)
704                 acpi_release_global_lock(glk);
705 unlock:
706         mutex_unlock(&ec->mutex);
707         return status;
708 }
709 
710 static int acpi_ec_burst_enable(struct acpi_ec *ec)
711 {
712         u8 d;
713         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
714                                 .wdata = NULL, .rdata = &d,
715                                 .wlen = 0, .rlen = 1};
716 
717         return acpi_ec_transaction(ec, &t);
718 }
719 
720 static int acpi_ec_burst_disable(struct acpi_ec *ec)
721 {
722         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
723                                 .wdata = NULL, .rdata = NULL,
724                                 .wlen = 0, .rlen = 0};
725 
726         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
727                                 acpi_ec_transaction(ec, &t) : 0;
728 }
729 
730 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
731 {
732         int result;
733         u8 d;
734         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
735                                 .wdata = &address, .rdata = &d,
736                                 .wlen = 1, .rlen = 1};
737 
738         result = acpi_ec_transaction(ec, &t);
739         *data = d;
740         return result;
741 }
742 
743 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
744 {
745         u8 wdata[2] = { address, data };
746         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
747                                 .wdata = wdata, .rdata = NULL,
748                                 .wlen = 2, .rlen = 0};
749 
750         return acpi_ec_transaction(ec, &t);
751 }
752 
753 int ec_read(u8 addr, u8 *val)
754 {
755         int err;
756         u8 temp_data;
757 
758         if (!first_ec)
759                 return -ENODEV;
760 
761         err = acpi_ec_read(first_ec, addr, &temp_data);
762 
763         if (!err) {
764                 *val = temp_data;
765                 return 0;
766         }
767         return err;
768 }
769 EXPORT_SYMBOL(ec_read);
770 
771 int ec_write(u8 addr, u8 val)
772 {
773         int err;
774 
775         if (!first_ec)
776                 return -ENODEV;
777 
778         err = acpi_ec_write(first_ec, addr, val);
779 
780         return err;
781 }
782 EXPORT_SYMBOL(ec_write);
783 
784 int ec_transaction(u8 command,
785                    const u8 *wdata, unsigned wdata_len,
786                    u8 *rdata, unsigned rdata_len)
787 {
788         struct transaction t = {.command = command,
789                                 .wdata = wdata, .rdata = rdata,
790                                 .wlen = wdata_len, .rlen = rdata_len};
791 
792         if (!first_ec)
793                 return -ENODEV;
794 
795         return acpi_ec_transaction(first_ec, &t);
796 }
797 EXPORT_SYMBOL(ec_transaction);
798 
799 /* Get the handle to the EC device */
800 acpi_handle ec_get_handle(void)
801 {
802         if (!first_ec)
803                 return NULL;
804         return first_ec->handle;
805 }
806 EXPORT_SYMBOL(ec_get_handle);
807 
808 /*
809  * Process _Q events that might have accumulated in the EC.
810  * Run with locked ec mutex.
811  */
812 static void acpi_ec_clear(struct acpi_ec *ec)
813 {
814         int i, status;
815         u8 value = 0;
816 
817         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
818                 status = acpi_ec_query(ec, &value);
819                 if (status || !value)
820                         break;
821         }
822 
823         if (unlikely(i == ACPI_EC_CLEAR_MAX))
824                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
825         else
826                 pr_info("%d stale EC events cleared\n", i);
827 }
828 
829 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
830 {
831         unsigned long flags;
832 
833         spin_lock_irqsave(&ec->lock, flags);
834         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
835                 ec_dbg_drv("Starting EC");
836                 /* Enable GPE for event processing (SCI_EVT=1) */
837                 if (!resuming) {
838                         acpi_ec_submit_request(ec);
839                         ec_dbg_ref(ec, "Increase driver");
840                 }
841                 ec_log_drv("EC started");
842         }
843         spin_unlock_irqrestore(&ec->lock, flags);
844 }
845 
846 static bool acpi_ec_stopped(struct acpi_ec *ec)
847 {
848         unsigned long flags;
849         bool flushed;
850 
851         spin_lock_irqsave(&ec->lock, flags);
852         flushed = acpi_ec_flushed(ec);
853         spin_unlock_irqrestore(&ec->lock, flags);
854         return flushed;
855 }
856 
857 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
858 {
859         unsigned long flags;
860 
861         spin_lock_irqsave(&ec->lock, flags);
862         if (acpi_ec_started(ec)) {
863                 ec_dbg_drv("Stopping EC");
864                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
865                 spin_unlock_irqrestore(&ec->lock, flags);
866                 wait_event(ec->wait, acpi_ec_stopped(ec));
867                 spin_lock_irqsave(&ec->lock, flags);
868                 /* Disable GPE for event processing (SCI_EVT=1) */
869                 if (!suspending) {
870                         acpi_ec_complete_request(ec);
871                         ec_dbg_ref(ec, "Decrease driver");
872                 }
873                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
874                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
875                 ec_log_drv("EC stopped");
876         }
877         spin_unlock_irqrestore(&ec->lock, flags);
878 }
879 
880 void acpi_ec_block_transactions(void)
881 {
882         struct acpi_ec *ec = first_ec;
883 
884         if (!ec)
885                 return;
886 
887         mutex_lock(&ec->mutex);
888         /* Prevent transactions from being carried out */
889         acpi_ec_stop(ec, true);
890         mutex_unlock(&ec->mutex);
891 }
892 
893 void acpi_ec_unblock_transactions(void)
894 {
895         struct acpi_ec *ec = first_ec;
896 
897         if (!ec)
898                 return;
899 
900         /* Allow transactions to be carried out again */
901         acpi_ec_start(ec, true);
902 
903         if (EC_FLAGS_CLEAR_ON_RESUME)
904                 acpi_ec_clear(ec);
905 }
906 
907 void acpi_ec_unblock_transactions_early(void)
908 {
909         /*
910          * Allow transactions to happen again (this function is called from
911          * atomic context during wakeup, so we don't need to acquire the mutex).
912          */
913         if (first_ec)
914                 acpi_ec_start(first_ec, true);
915 }
916 
917 /* --------------------------------------------------------------------------
918                                 Event Management
919    -------------------------------------------------------------------------- */
920 static struct acpi_ec_query_handler *
921 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
922 {
923         if (handler)
924                 kref_get(&handler->kref);
925         return handler;
926 }
927 
928 static void acpi_ec_query_handler_release(struct kref *kref)
929 {
930         struct acpi_ec_query_handler *handler =
931                 container_of(kref, struct acpi_ec_query_handler, kref);
932 
933         kfree(handler);
934 }
935 
936 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
937 {
938         kref_put(&handler->kref, acpi_ec_query_handler_release);
939 }
940 
941 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
942                               acpi_handle handle, acpi_ec_query_func func,
943                               void *data)
944 {
945         struct acpi_ec_query_handler *handler =
946             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
947 
948         if (!handler)
949                 return -ENOMEM;
950 
951         handler->query_bit = query_bit;
952         handler->handle = handle;
953         handler->func = func;
954         handler->data = data;
955         mutex_lock(&ec->mutex);
956         kref_init(&handler->kref);
957         list_add(&handler->node, &ec->list);
958         mutex_unlock(&ec->mutex);
959         return 0;
960 }
961 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
962 
963 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
964 {
965         struct acpi_ec_query_handler *handler, *tmp;
966         LIST_HEAD(free_list);
967 
968         mutex_lock(&ec->mutex);
969         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
970                 if (query_bit == handler->query_bit) {
971                         list_del_init(&handler->node);
972                         list_add(&handler->node, &free_list);
973                 }
974         }
975         mutex_unlock(&ec->mutex);
976         list_for_each_entry_safe(handler, tmp, &free_list, node)
977                 acpi_ec_put_query_handler(handler);
978 }
979 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
980 
981 static void acpi_ec_run(void *cxt)
982 {
983         struct acpi_ec_query_handler *handler = cxt;
984 
985         if (!handler)
986                 return;
987         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
988         if (handler->func)
989                 handler->func(handler->data);
990         else if (handler->handle)
991                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
992         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
993         acpi_ec_put_query_handler(handler);
994 }
995 
996 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
997 {
998         u8 value = 0;
999         int result;
1000         acpi_status status;
1001         struct acpi_ec_query_handler *handler;
1002         struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
1003                                 .wdata = NULL, .rdata = &value,
1004                                 .wlen = 0, .rlen = 1};
1005 
1006         /*
1007          * Query the EC to find out which _Qxx method we need to evaluate.
1008          * Note that successful completion of the query causes the ACPI_EC_SCI
1009          * bit to be cleared (and thus clearing the interrupt source).
1010          */
1011         result = acpi_ec_transaction(ec, &t);
1012         if (result)
1013                 return result;
1014         if (data)
1015                 *data = value;
1016         if (!value)
1017                 return -ENODATA;
1018 
1019         mutex_lock(&ec->mutex);
1020         list_for_each_entry(handler, &ec->list, node) {
1021                 if (value == handler->query_bit) {
1022                         /* have custom handler for this bit */
1023                         handler = acpi_ec_get_query_handler(handler);
1024                         ec_dbg_evt("Query(0x%02x) scheduled",
1025                                    handler->query_bit);
1026                         status = acpi_os_execute((handler->func) ?
1027                                 OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
1028                                 acpi_ec_run, handler);
1029                         if (ACPI_FAILURE(status))
1030                                 result = -EBUSY;
1031                         break;
1032                 }
1033         }
1034         mutex_unlock(&ec->mutex);
1035         return result;
1036 }
1037 
1038 static void acpi_ec_check_event(struct acpi_ec *ec)
1039 {
1040         unsigned long flags;
1041 
1042         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1043                 if (ec_guard(ec)) {
1044                         spin_lock_irqsave(&ec->lock, flags);
1045                         /*
1046                          * Take care of the SCI_EVT unless no one else is
1047                          * taking care of it.
1048                          */
1049                         if (!ec->curr)
1050                                 advance_transaction(ec);
1051                         spin_unlock_irqrestore(&ec->lock, flags);
1052                 }
1053         }
1054 }
1055 
1056 static void acpi_ec_event_handler(struct work_struct *work)
1057 {
1058         unsigned long flags;
1059         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1060 
1061         ec_dbg_evt("Event started");
1062 
1063         spin_lock_irqsave(&ec->lock, flags);
1064         while (ec->nr_pending_queries) {
1065                 spin_unlock_irqrestore(&ec->lock, flags);
1066                 (void)acpi_ec_query(ec, NULL);
1067                 spin_lock_irqsave(&ec->lock, flags);
1068                 ec->nr_pending_queries--;
1069                 /*
1070                  * Before exit, make sure that this work item can be
1071                  * scheduled again. There might be QR_EC failures, leaving
1072                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1073                  * item from being scheduled again.
1074                  */
1075                 if (!ec->nr_pending_queries) {
1076                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1077                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1078                                 acpi_ec_complete_query(ec);
1079                 }
1080         }
1081         spin_unlock_irqrestore(&ec->lock, flags);
1082 
1083         ec_dbg_evt("Event stopped");
1084 
1085         acpi_ec_check_event(ec);
1086 }
1087 
1088 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1089         u32 gpe_number, void *data)
1090 {
1091         unsigned long flags;
1092         struct acpi_ec *ec = data;
1093 
1094         spin_lock_irqsave(&ec->lock, flags);
1095         advance_transaction(ec);
1096         spin_unlock_irqrestore(&ec->lock, flags);
1097         return ACPI_INTERRUPT_HANDLED;
1098 }
1099 
1100 /* --------------------------------------------------------------------------
1101  *                           Address Space Management
1102  * -------------------------------------------------------------------------- */
1103 
1104 static acpi_status
1105 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1106                       u32 bits, u64 *value64,
1107                       void *handler_context, void *region_context)
1108 {
1109         struct acpi_ec *ec = handler_context;
1110         int result = 0, i, bytes = bits / 8;
1111         u8 *value = (u8 *)value64;
1112 
1113         if ((address > 0xFF) || !value || !handler_context)
1114                 return AE_BAD_PARAMETER;
1115 
1116         if (function != ACPI_READ && function != ACPI_WRITE)
1117                 return AE_BAD_PARAMETER;
1118 
1119         if (ec_busy_polling || bits > 8)
1120                 acpi_ec_burst_enable(ec);
1121 
1122         for (i = 0; i < bytes; ++i, ++address, ++value)
1123                 result = (function == ACPI_READ) ?
1124                         acpi_ec_read(ec, address, value) :
1125                         acpi_ec_write(ec, address, *value);
1126 
1127         if (ec_busy_polling || bits > 8)
1128                 acpi_ec_burst_disable(ec);
1129 
1130         switch (result) {
1131         case -EINVAL:
1132                 return AE_BAD_PARAMETER;
1133         case -ENODEV:
1134                 return AE_NOT_FOUND;
1135         case -ETIME:
1136                 return AE_TIME;
1137         default:
1138                 return AE_OK;
1139         }
1140 }
1141 
1142 /* --------------------------------------------------------------------------
1143  *                             Driver Interface
1144  * -------------------------------------------------------------------------- */
1145 
1146 static acpi_status
1147 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1148 
1149 static struct acpi_ec *make_acpi_ec(void)
1150 {
1151         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1152 
1153         if (!ec)
1154                 return NULL;
1155         ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
1156         mutex_init(&ec->mutex);
1157         init_waitqueue_head(&ec->wait);
1158         INIT_LIST_HEAD(&ec->list);
1159         spin_lock_init(&ec->lock);
1160         INIT_WORK(&ec->work, acpi_ec_event_handler);
1161         ec->timestamp = jiffies;
1162         return ec;
1163 }
1164 
1165 static acpi_status
1166 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1167                                void *context, void **return_value)
1168 {
1169         char node_name[5];
1170         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1171         struct acpi_ec *ec = context;
1172         int value = 0;
1173         acpi_status status;
1174 
1175         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1176 
1177         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1178                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1179         return AE_OK;
1180 }
1181 
1182 static acpi_status
1183 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1184 {
1185         acpi_status status;
1186         unsigned long long tmp = 0;
1187         struct acpi_ec *ec = context;
1188 
1189         /* clear addr values, ec_parse_io_ports depend on it */
1190         ec->command_addr = ec->data_addr = 0;
1191 
1192         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1193                                      ec_parse_io_ports, ec);
1194         if (ACPI_FAILURE(status))
1195                 return status;
1196 
1197         /* Get GPE bit assignment (EC events). */
1198         /* TODO: Add support for _GPE returning a package */
1199         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1200         if (ACPI_FAILURE(status))
1201                 return status;
1202         ec->gpe = tmp;
1203         /* Use the global lock for all EC transactions? */
1204         tmp = 0;
1205         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1206         ec->global_lock = tmp;
1207         ec->handle = handle;
1208         return AE_CTRL_TERMINATE;
1209 }
1210 
1211 static int ec_install_handlers(struct acpi_ec *ec)
1212 {
1213         acpi_status status;
1214 
1215         if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1216                 return 0;
1217         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1218                                   ACPI_GPE_EDGE_TRIGGERED,
1219                                   &acpi_ec_gpe_handler, ec);
1220         if (ACPI_FAILURE(status))
1221                 return -ENODEV;
1222 
1223         acpi_ec_start(ec, false);
1224         status = acpi_install_address_space_handler(ec->handle,
1225                                                     ACPI_ADR_SPACE_EC,
1226                                                     &acpi_ec_space_handler,
1227                                                     NULL, ec);
1228         if (ACPI_FAILURE(status)) {
1229                 if (status == AE_NOT_FOUND) {
1230                         /*
1231                          * Maybe OS fails in evaluating the _REG object.
1232                          * The AE_NOT_FOUND error will be ignored and OS
1233                          * continue to initialize EC.
1234                          */
1235                         pr_err("Fail in evaluating the _REG object"
1236                                 " of EC device. Broken bios is suspected.\n");
1237                 } else {
1238                         acpi_ec_stop(ec, false);
1239                         acpi_remove_gpe_handler(NULL, ec->gpe,
1240                                 &acpi_ec_gpe_handler);
1241                         return -ENODEV;
1242                 }
1243         }
1244 
1245         set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1246         return 0;
1247 }
1248 
1249 static void ec_remove_handlers(struct acpi_ec *ec)
1250 {
1251         if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1252                 return;
1253         acpi_ec_stop(ec, false);
1254         if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1255                                 ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1256                 pr_err("failed to remove space handler\n");
1257         if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1258                                 &acpi_ec_gpe_handler)))
1259                 pr_err("failed to remove gpe handler\n");
1260         clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1261 }
1262 
1263 static int acpi_ec_add(struct acpi_device *device)
1264 {
1265         struct acpi_ec *ec = NULL;
1266         int ret;
1267 
1268         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1269         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1270 
1271         /* Check for boot EC */
1272         if (boot_ec &&
1273             (boot_ec->handle == device->handle ||
1274              boot_ec->handle == ACPI_ROOT_OBJECT)) {
1275                 ec = boot_ec;
1276                 boot_ec = NULL;
1277         } else {
1278                 ec = make_acpi_ec();
1279                 if (!ec)
1280                         return -ENOMEM;
1281         }
1282         if (ec_parse_device(device->handle, 0, ec, NULL) !=
1283                 AE_CTRL_TERMINATE) {
1284                         kfree(ec);
1285                         return -EINVAL;
1286         }
1287 
1288         /* Find and register all query methods */
1289         acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1290                             acpi_ec_register_query_methods, NULL, ec, NULL);
1291 
1292         if (!first_ec)
1293                 first_ec = ec;
1294         device->driver_data = ec;
1295 
1296         ret = !!request_region(ec->data_addr, 1, "EC data");
1297         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1298         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1299         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1300 
1301         pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1302                           ec->gpe, ec->command_addr, ec->data_addr);
1303 
1304         ret = ec_install_handlers(ec);
1305 
1306         /* Reprobe devices depending on the EC */
1307         acpi_walk_dep_device_list(ec->handle);
1308 
1309         /* EC is fully operational, allow queries */
1310         clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1311 
1312         /* Clear stale _Q events if hardware might require that */
1313         if (EC_FLAGS_CLEAR_ON_RESUME)
1314                 acpi_ec_clear(ec);
1315         return ret;
1316 }
1317 
1318 static int acpi_ec_remove(struct acpi_device *device)
1319 {
1320         struct acpi_ec *ec;
1321         struct acpi_ec_query_handler *handler, *tmp;
1322 
1323         if (!device)
1324                 return -EINVAL;
1325 
1326         ec = acpi_driver_data(device);
1327         ec_remove_handlers(ec);
1328         mutex_lock(&ec->mutex);
1329         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1330                 list_del(&handler->node);
1331                 kfree(handler);
1332         }
1333         mutex_unlock(&ec->mutex);
1334         release_region(ec->data_addr, 1);
1335         release_region(ec->command_addr, 1);
1336         device->driver_data = NULL;
1337         if (ec == first_ec)
1338                 first_ec = NULL;
1339         kfree(ec);
1340         return 0;
1341 }
1342 
1343 static acpi_status
1344 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1345 {
1346         struct acpi_ec *ec = context;
1347 
1348         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1349                 return AE_OK;
1350 
1351         /*
1352          * The first address region returned is the data port, and
1353          * the second address region returned is the status/command
1354          * port.
1355          */
1356         if (ec->data_addr == 0)
1357                 ec->data_addr = resource->data.io.minimum;
1358         else if (ec->command_addr == 0)
1359                 ec->command_addr = resource->data.io.minimum;
1360         else
1361                 return AE_CTRL_TERMINATE;
1362 
1363         return AE_OK;
1364 }
1365 
1366 int __init acpi_boot_ec_enable(void)
1367 {
1368         if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1369                 return 0;
1370         if (!ec_install_handlers(boot_ec)) {
1371                 first_ec = boot_ec;
1372                 return 0;
1373         }
1374         return -EFAULT;
1375 }
1376 
1377 static const struct acpi_device_id ec_device_ids[] = {
1378         {"PNP0C09", 0},
1379         {"", 0},
1380 };
1381 
1382 /* Some BIOS do not survive early DSDT scan, skip it */
1383 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1384 {
1385         EC_FLAGS_SKIP_DSDT_SCAN = 1;
1386         return 0;
1387 }
1388 
1389 /* ASUStek often supplies us with broken ECDT, validate it */
1390 static int ec_validate_ecdt(const struct dmi_system_id *id)
1391 {
1392         EC_FLAGS_VALIDATE_ECDT = 1;
1393         return 0;
1394 }
1395 
1396 #if 0
1397 /*
1398  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1399  * set, for which case, we complete the QR_EC without issuing it to the
1400  * firmware.
1401  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1402  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1403  */
1404 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1405 {
1406         pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1407         EC_FLAGS_QUERY_HANDSHAKE = 1;
1408         return 0;
1409 }
1410 #endif
1411 
1412 /*
1413  * On some hardware it is necessary to clear events accumulated by the EC during
1414  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1415  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1416  *
1417  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1418  *
1419  * Ideally, the EC should also be instructed NOT to accumulate events during
1420  * sleep (which Windows seems to do somehow), but the interface to control this
1421  * behaviour is not known at this time.
1422  *
1423  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1424  * however it is very likely that other Samsung models are affected.
1425  *
1426  * On systems which don't accumulate _Q events during sleep, this extra check
1427  * should be harmless.
1428  */
1429 static int ec_clear_on_resume(const struct dmi_system_id *id)
1430 {
1431         pr_debug("Detected system needing EC poll on resume.\n");
1432         EC_FLAGS_CLEAR_ON_RESUME = 1;
1433         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1434         return 0;
1435 }
1436 
1437 static struct dmi_system_id ec_dmi_table[] __initdata = {
1438         {
1439         ec_skip_dsdt_scan, "Compal JFL92", {
1440         DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1441         DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1442         {
1443         ec_validate_ecdt, "MSI MS-171F", {
1444         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1445         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1446         {
1447         ec_validate_ecdt, "ASUS hardware", {
1448         DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1449         {
1450         ec_validate_ecdt, "ASUS hardware", {
1451         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1452         {
1453         ec_skip_dsdt_scan, "HP Folio 13", {
1454         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1455         DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1456         {
1457         ec_validate_ecdt, "ASUS hardware", {
1458         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1459         DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1460         {
1461         ec_clear_on_resume, "Samsung hardware", {
1462         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1463         {},
1464 };
1465 
1466 int __init acpi_ec_ecdt_probe(void)
1467 {
1468         acpi_status status;
1469         struct acpi_ec *saved_ec = NULL;
1470         struct acpi_table_ecdt *ecdt_ptr;
1471 
1472         boot_ec = make_acpi_ec();
1473         if (!boot_ec)
1474                 return -ENOMEM;
1475         /*
1476          * Generate a boot ec context
1477          */
1478         dmi_check_system(ec_dmi_table);
1479         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1480                                 (struct acpi_table_header **)&ecdt_ptr);
1481         if (ACPI_SUCCESS(status)) {
1482                 pr_info("EC description table is found, configuring boot EC\n");
1483                 boot_ec->command_addr = ecdt_ptr->control.address;
1484                 boot_ec->data_addr = ecdt_ptr->data.address;
1485                 boot_ec->gpe = ecdt_ptr->gpe;
1486                 boot_ec->handle = ACPI_ROOT_OBJECT;
1487                 acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1488                                 &boot_ec->handle);
1489                 /* Don't trust ECDT, which comes from ASUSTek */
1490                 if (!EC_FLAGS_VALIDATE_ECDT)
1491                         goto install;
1492                 saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1493                 if (!saved_ec)
1494                         return -ENOMEM;
1495         /* fall through */
1496         }
1497 
1498         if (EC_FLAGS_SKIP_DSDT_SCAN) {
1499                 kfree(saved_ec);
1500                 return -ENODEV;
1501         }
1502 
1503         /* This workaround is needed only on some broken machines,
1504          * which require early EC, but fail to provide ECDT */
1505         pr_debug("Look up EC in DSDT\n");
1506         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1507                                         boot_ec, NULL);
1508         /* Check that acpi_get_devices actually find something */
1509         if (ACPI_FAILURE(status) || !boot_ec->handle)
1510                 goto error;
1511         if (saved_ec) {
1512                 /* try to find good ECDT from ASUSTek */
1513                 if (saved_ec->command_addr != boot_ec->command_addr ||
1514                     saved_ec->data_addr != boot_ec->data_addr ||
1515                     saved_ec->gpe != boot_ec->gpe ||
1516                     saved_ec->handle != boot_ec->handle)
1517                         pr_info("ASUSTek keeps feeding us with broken "
1518                         "ECDT tables, which are very hard to workaround. "
1519                         "Trying to use DSDT EC info instead. Please send "
1520                         "output of acpidump to linux-acpi@vger.kernel.org\n");
1521                 kfree(saved_ec);
1522                 saved_ec = NULL;
1523         } else {
1524                 /* We really need to limit this workaround, the only ASUS,
1525                 * which needs it, has fake EC._INI method, so use it as flag.
1526                 * Keep boot_ec struct as it will be needed soon.
1527                 */
1528                 if (!dmi_name_in_vendors("ASUS") ||
1529                     !acpi_has_method(boot_ec->handle, "_INI"))
1530                         return -ENODEV;
1531         }
1532 install:
1533         if (!ec_install_handlers(boot_ec)) {
1534                 first_ec = boot_ec;
1535                 return 0;
1536         }
1537 error:
1538         kfree(boot_ec);
1539         kfree(saved_ec);
1540         boot_ec = NULL;
1541         return -ENODEV;
1542 }
1543 
1544 static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1545 {
1546         int result = 0;
1547 
1548         if (!strncmp(val, "status", sizeof("status") - 1)) {
1549                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1550                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1551         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1552                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1553                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1554         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1555                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1556                 pr_info("Assuming SCI_EVT clearing on event reads\n");
1557         } else
1558                 result = -EINVAL;
1559         return result;
1560 }
1561 
1562 static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1563 {
1564         switch (ec_event_clearing) {
1565         case ACPI_EC_EVT_TIMING_STATUS:
1566                 return sprintf(buffer, "status");
1567         case ACPI_EC_EVT_TIMING_QUERY:
1568                 return sprintf(buffer, "query");
1569         case ACPI_EC_EVT_TIMING_EVENT:
1570                 return sprintf(buffer, "event");
1571         default:
1572                 return sprintf(buffer, "invalid");
1573         }
1574         return 0;
1575 }
1576 
1577 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1578                   NULL, 0644);
1579 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1580 
1581 static struct acpi_driver acpi_ec_driver = {
1582         .name = "ec",
1583         .class = ACPI_EC_CLASS,
1584         .ids = ec_device_ids,
1585         .ops = {
1586                 .add = acpi_ec_add,
1587                 .remove = acpi_ec_remove,
1588                 },
1589 };
1590 
1591 int __init acpi_ec_init(void)
1592 {
1593         int result = 0;
1594 
1595         /* Now register the driver for the EC */
1596         result = acpi_bus_register_driver(&acpi_ec_driver);
1597         if (result < 0)
1598                 return -ENODEV;
1599 
1600         return result;
1601 }
1602 
1603 /* EC driver currently not unloadable */
1604 #if 0
1605 static void __exit acpi_ec_exit(void)
1606 {
1607 
1608         acpi_bus_unregister_driver(&acpi_ec_driver);
1609 }
1610 #endif  /* 0 */
1611 

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