source: src/linux/universal/linux-4.9/drivers/acpi/ec.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 2 months ago

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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 */
91enum ec_command {
92        ACPI_EC_COMMAND_READ = 0x80,
93        ACPI_EC_COMMAND_WRITE = 0x81,
94        ACPI_EC_BURST_ENABLE = 0x82,
95        ACPI_EC_BURST_DISABLE = 0x83,
96        ACPI_EC_COMMAND_QUERY = 0x84,
97};
98
99#define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
100#define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
101#define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
102#define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
103                                         * when trying to clear the EC */
104#define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
105
106enum {
107        EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
108        EC_FLAGS_QUERY_PENDING,         /* Query is pending */
109        EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
110        EC_FLAGS_GPE_HANDLER_INSTALLED, /* GPE handler installed */
111        EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
112        EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
113        EC_FLAGS_STARTED,               /* Driver is started */
114        EC_FLAGS_STOPPED,               /* Driver is stopped */
115        EC_FLAGS_COMMAND_STORM,         /* GPE storms occurred to the
116                                         * current command processing */
117};
118
119#define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
120#define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
121
122/* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
123static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
124module_param(ec_delay, uint, 0644);
125MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
126
127static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
128module_param(ec_max_queries, uint, 0644);
129MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
130
131static bool ec_busy_polling __read_mostly;
132module_param(ec_busy_polling, bool, 0644);
133MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
134
135static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
136module_param(ec_polling_guard, uint, 0644);
137MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
138
139static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
140
141/*
142 * If the number of false interrupts per one transaction exceeds
143 * this threshold, will think there is a GPE storm happened and
144 * will disable the GPE for normal transaction.
145 */
146static unsigned int ec_storm_threshold  __read_mostly = 8;
147module_param(ec_storm_threshold, uint, 0644);
148MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
149
150static bool ec_freeze_events __read_mostly = true;
151module_param(ec_freeze_events, bool, 0644);
152MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
153
154struct acpi_ec_query_handler {
155        struct list_head node;
156        acpi_ec_query_func func;
157        acpi_handle handle;
158        void *data;
159        u8 query_bit;
160        struct kref kref;
161};
162
163struct transaction {
164        const u8 *wdata;
165        u8 *rdata;
166        unsigned short irq_count;
167        u8 command;
168        u8 wi;
169        u8 ri;
170        u8 wlen;
171        u8 rlen;
172        u8 flags;
173};
174
175struct acpi_ec_query {
176        struct transaction transaction;
177        struct work_struct work;
178        struct acpi_ec_query_handler *handler;
179};
180
181static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
182static void advance_transaction(struct acpi_ec *ec);
183static void acpi_ec_event_handler(struct work_struct *work);
184static void acpi_ec_event_processor(struct work_struct *work);
185
186struct acpi_ec *boot_ec, *first_ec;
187EXPORT_SYMBOL(first_ec);
188static bool boot_ec_is_ecdt = false;
189static struct workqueue_struct *ec_query_wq;
190
191static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
192static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
193static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
194
195/* --------------------------------------------------------------------------
196 *                           Logging/Debugging
197 * -------------------------------------------------------------------------- */
198
199/*
200 * Splitters used by the developers to track the boundary of the EC
201 * handling processes.
202 */
203#ifdef DEBUG
204#define EC_DBG_SEP      " "
205#define EC_DBG_DRV      "+++++"
206#define EC_DBG_STM      "====="
207#define EC_DBG_REQ      "*****"
208#define EC_DBG_EVT      "#####"
209#else
210#define EC_DBG_SEP      ""
211#define EC_DBG_DRV
212#define EC_DBG_STM
213#define EC_DBG_REQ
214#define EC_DBG_EVT
215#endif
216
217#define ec_log_raw(fmt, ...) \
218        pr_info(fmt "\n", ##__VA_ARGS__)
219#define ec_dbg_raw(fmt, ...) \
220        pr_debug(fmt "\n", ##__VA_ARGS__)
221#define ec_log(filter, fmt, ...) \
222        ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
223#define ec_dbg(filter, fmt, ...) \
224        ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
225
226#define ec_log_drv(fmt, ...) \
227        ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
228#define ec_dbg_drv(fmt, ...) \
229        ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
230#define ec_dbg_stm(fmt, ...) \
231        ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
232#define ec_dbg_req(fmt, ...) \
233        ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
234#define ec_dbg_evt(fmt, ...) \
235        ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
236#define ec_dbg_ref(ec, fmt, ...) \
237        ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
238
239/* --------------------------------------------------------------------------
240 *                           Device Flags
241 * -------------------------------------------------------------------------- */
242
243static bool acpi_ec_started(struct acpi_ec *ec)
244{
245        return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
246               !test_bit(EC_FLAGS_STOPPED, &ec->flags);
247}
248
249static bool acpi_ec_event_enabled(struct acpi_ec *ec)
250{
251        /*
252         * There is an OSPM early stage logic. During the early stages
253         * (boot/resume), OSPMs shouldn't enable the event handling, only
254         * the EC transactions are allowed to be performed.
255         */
256        if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
257                return false;
258        /*
259         * However, disabling the event handling is experimental for late
260         * stage (suspend), and is controlled by the boot parameter of
261         * "ec_freeze_events":
262         * 1. true:  The EC event handling is disabled before entering
263         *           the noirq stage.
264         * 2. false: The EC event handling is automatically disabled as
265         *           soon as the EC driver is stopped.
266         */
267        if (ec_freeze_events)
268                return acpi_ec_started(ec);
269        else
270                return test_bit(EC_FLAGS_STARTED, &ec->flags);
271}
272
273static bool acpi_ec_flushed(struct acpi_ec *ec)
274{
275        return ec->reference_count == 1;
276}
277
278/* --------------------------------------------------------------------------
279 *                           EC Registers
280 * -------------------------------------------------------------------------- */
281
282static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
283{
284        u8 x = inb(ec->command_addr);
285
286        ec_dbg_raw("EC_SC(R) = 0x%2.2x "
287                   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
288                   x,
289                   !!(x & ACPI_EC_FLAG_SCI),
290                   !!(x & ACPI_EC_FLAG_BURST),
291                   !!(x & ACPI_EC_FLAG_CMD),
292                   !!(x & ACPI_EC_FLAG_IBF),
293                   !!(x & ACPI_EC_FLAG_OBF));
294        return x;
295}
296
297static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
298{
299        u8 x = inb(ec->data_addr);
300
301        ec->timestamp = jiffies;
302        ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
303        return x;
304}
305
306static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
307{
308        ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
309        outb(command, ec->command_addr);
310        ec->timestamp = jiffies;
311}
312
313static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
314{
315        ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
316        outb(data, ec->data_addr);
317        ec->timestamp = jiffies;
318}
319
320#ifdef DEBUG
321static const char *acpi_ec_cmd_string(u8 cmd)
322{
323        switch (cmd) {
324        case 0x80:
325                return "RD_EC";
326        case 0x81:
327                return "WR_EC";
328        case 0x82:
329                return "BE_EC";
330        case 0x83:
331                return "BD_EC";
332        case 0x84:
333                return "QR_EC";
334        }
335        return "UNKNOWN";
336}
337#else
338#define acpi_ec_cmd_string(cmd)         "UNDEF"
339#endif
340
341/* --------------------------------------------------------------------------
342 *                           GPE Registers
343 * -------------------------------------------------------------------------- */
344
345static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
346{
347        acpi_event_status gpe_status = 0;
348
349        (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
350        return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
351}
352
353static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
354{
355        if (open)
356                acpi_enable_gpe(NULL, ec->gpe);
357        else {
358                BUG_ON(ec->reference_count < 1);
359                acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
360        }
361        if (acpi_ec_is_gpe_raised(ec)) {
362                /*
363                 * On some platforms, EN=1 writes cannot trigger GPE. So
364                 * software need to manually trigger a pseudo GPE event on
365                 * EN=1 writes.
366                 */
367                ec_dbg_raw("Polling quirk");
368                advance_transaction(ec);
369        }
370}
371
372static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
373{
374        if (close)
375                acpi_disable_gpe(NULL, ec->gpe);
376        else {
377                BUG_ON(ec->reference_count < 1);
378                acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
379        }
380}
381
382static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
383{
384        /*
385         * GPE STS is a W1C register, which means:
386         * 1. Software can clear it without worrying about clearing other
387         *    GPEs' STS bits when the hardware sets them in parallel.
388         * 2. As long as software can ensure only clearing it when it is
389         *    set, hardware won't set it in parallel.
390         * So software can clear GPE in any contexts.
391         * Warning: do not move the check into advance_transaction() as the
392         * EC commands will be sent without GPE raised.
393         */
394        if (!acpi_ec_is_gpe_raised(ec))
395                return;
396        acpi_clear_gpe(NULL, ec->gpe);
397}
398
399/* --------------------------------------------------------------------------
400 *                           Transaction Management
401 * -------------------------------------------------------------------------- */
402
403static void acpi_ec_submit_request(struct acpi_ec *ec)
404{
405        ec->reference_count++;
406        if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
407            ec->reference_count == 1)
408                acpi_ec_enable_gpe(ec, true);
409}
410
411static void acpi_ec_complete_request(struct acpi_ec *ec)
412{
413        bool flushed = false;
414
415        ec->reference_count--;
416        if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
417            ec->reference_count == 0)
418                acpi_ec_disable_gpe(ec, true);
419        flushed = acpi_ec_flushed(ec);
420        if (flushed)
421                wake_up(&ec->wait);
422}
423
424static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
425{
426        if (!test_bit(flag, &ec->flags)) {
427                acpi_ec_disable_gpe(ec, false);
428                ec_dbg_drv("Polling enabled");
429                set_bit(flag, &ec->flags);
430        }
431}
432
433static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
434{
435        if (test_bit(flag, &ec->flags)) {
436                clear_bit(flag, &ec->flags);
437                acpi_ec_enable_gpe(ec, false);
438                ec_dbg_drv("Polling disabled");
439        }
440}
441
442/*
443 * acpi_ec_submit_flushable_request() - Increase the reference count unless
444 *                                      the flush operation is not in
445 *                                      progress
446 * @ec: the EC device
447 *
448 * This function must be used before taking a new action that should hold
449 * the reference count.  If this function returns false, then the action
450 * must be discarded or it will prevent the flush operation from being
451 * completed.
452 */
453static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
454{
455        if (!acpi_ec_started(ec))
456                return false;
457        acpi_ec_submit_request(ec);
458        return true;
459}
460
461static void acpi_ec_submit_query(struct acpi_ec *ec)
462{
463        if (acpi_ec_event_enabled(ec) &&
464            !test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
465                ec_dbg_evt("Command(%s) submitted/blocked",
466                           acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
467                ec->nr_pending_queries++;
468                schedule_work(&ec->work);
469        }
470}
471
472static void acpi_ec_complete_query(struct acpi_ec *ec)
473{
474        if (test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
475                clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
476                ec_dbg_evt("Command(%s) unblocked",
477                           acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
478        }
479}
480
481static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
482{
483        if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
484                ec_log_drv("event unblocked");
485        if (!test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
486                advance_transaction(ec);
487}
488
489static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
490{
491        if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
492                ec_log_drv("event blocked");
493}
494
495/*
496 * Process _Q events that might have accumulated in the EC.
497 * Run with locked ec mutex.
498 */
499static void acpi_ec_clear(struct acpi_ec *ec)
500{
501        int i, status;
502        u8 value = 0;
503
504        for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
505                status = acpi_ec_query(ec, &value);
506                if (status || !value)
507                        break;
508        }
509        if (unlikely(i == ACPI_EC_CLEAR_MAX))
510                pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
511        else
512                pr_info("%d stale EC events cleared\n", i);
513}
514
515static void acpi_ec_enable_event(struct acpi_ec *ec)
516{
517        unsigned long flags;
518
519        spin_lock_irqsave(&ec->lock, flags);
520        if (acpi_ec_started(ec))
521                __acpi_ec_enable_event(ec);
522        spin_unlock_irqrestore(&ec->lock, flags);
523
524        /* Drain additional events if hardware requires that */
525        if (EC_FLAGS_CLEAR_ON_RESUME)
526                acpi_ec_clear(ec);
527}
528
529#ifdef CONFIG_PM_SLEEP
530static bool acpi_ec_query_flushed(struct acpi_ec *ec)
531{
532        bool flushed;
533        unsigned long flags;
534
535        spin_lock_irqsave(&ec->lock, flags);
536        flushed = !ec->nr_pending_queries;
537        spin_unlock_irqrestore(&ec->lock, flags);
538        return flushed;
539}
540
541static void __acpi_ec_flush_event(struct acpi_ec *ec)
542{
543        /*
544         * When ec_freeze_events is true, we need to flush events in
545         * the proper position before entering the noirq stage.
546         */
547        wait_event(ec->wait, acpi_ec_query_flushed(ec));
548        if (ec_query_wq)
549                flush_workqueue(ec_query_wq);
550}
551
552static void acpi_ec_disable_event(struct acpi_ec *ec)
553{
554        unsigned long flags;
555
556        spin_lock_irqsave(&ec->lock, flags);
557        __acpi_ec_disable_event(ec);
558        spin_unlock_irqrestore(&ec->lock, flags);
559        __acpi_ec_flush_event(ec);
560}
561#endif /* CONFIG_PM_SLEEP */
562
563static bool acpi_ec_guard_event(struct acpi_ec *ec)
564{
565        bool guarded = true;
566        unsigned long flags;
567
568        spin_lock_irqsave(&ec->lock, flags);
569        /*
570         * If firmware SCI_EVT clearing timing is "event", we actually
571         * don't know when the SCI_EVT will be cleared by firmware after
572         * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
573         * acceptable period.
574         *
575         * The guarding period begins when EC_FLAGS_QUERY_PENDING is
576         * flagged, which means SCI_EVT check has just been performed.
577         * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
578         * guarding should have already been performed (via
579         * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
580         * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
581         * ACPI_EC_COMMAND_POLL state immediately.
582         */
583        if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
584            ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
585            !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
586            (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
587                guarded = false;
588        spin_unlock_irqrestore(&ec->lock, flags);
589        return guarded;
590}
591
592static int ec_transaction_polled(struct acpi_ec *ec)
593{
594        unsigned long flags;
595        int ret = 0;
596
597        spin_lock_irqsave(&ec->lock, flags);
598        if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
599                ret = 1;
600        spin_unlock_irqrestore(&ec->lock, flags);
601        return ret;
602}
603
604static int ec_transaction_completed(struct acpi_ec *ec)
605{
606        unsigned long flags;
607        int ret = 0;
608
609        spin_lock_irqsave(&ec->lock, flags);
610        if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
611                ret = 1;
612        spin_unlock_irqrestore(&ec->lock, flags);
613        return ret;
614}
615
616static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
617{
618        ec->curr->flags |= flag;
619        if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
620                if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
621                    flag == ACPI_EC_COMMAND_POLL)
622                        acpi_ec_complete_query(ec);
623                if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
624                    flag == ACPI_EC_COMMAND_COMPLETE)
625                        acpi_ec_complete_query(ec);
626                if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
627                    flag == ACPI_EC_COMMAND_COMPLETE)
628                        set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
629        }
630}
631
632static void advance_transaction(struct acpi_ec *ec)
633{
634        struct transaction *t;
635        u8 status;
636        bool wakeup = false;
637
638        ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
639                   smp_processor_id());
640        /*
641         * By always clearing STS before handling all indications, we can
642         * ensure a hardware STS 0->1 change after this clearing can always
643         * trigger a GPE interrupt.
644         */
645        acpi_ec_clear_gpe(ec);
646        status = acpi_ec_read_status(ec);
647        t = ec->curr;
648        /*
649         * Another IRQ or a guarded polling mode advancement is detected,
650         * the next QR_EC submission is then allowed.
651         */
652        if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
653                if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
654                    (!ec->nr_pending_queries ||
655                     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
656                        clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
657                        acpi_ec_complete_query(ec);
658                }
659        }
660        if (!t)
661                goto err;
662        if (t->flags & ACPI_EC_COMMAND_POLL) {
663                if (t->wlen > t->wi) {
664                        if ((status & ACPI_EC_FLAG_IBF) == 0)
665                                acpi_ec_write_data(ec, t->wdata[t->wi++]);
666                        else
667                                goto err;
668                } else if (t->rlen > t->ri) {
669                        if ((status & ACPI_EC_FLAG_OBF) == 1) {
670                                t->rdata[t->ri++] = acpi_ec_read_data(ec);
671                                if (t->rlen == t->ri) {
672                                        ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
673                                        if (t->command == ACPI_EC_COMMAND_QUERY)
674                                                ec_dbg_evt("Command(%s) completed by hardware",
675                                                           acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
676                                        wakeup = true;
677                                }
678                        } else
679                                goto err;
680                } else if (t->wlen == t->wi &&
681                           (status & ACPI_EC_FLAG_IBF) == 0) {
682                        ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
683                        wakeup = true;
684                }
685                goto out;
686        } else {
687                if (EC_FLAGS_QUERY_HANDSHAKE &&
688                    !(status & ACPI_EC_FLAG_SCI) &&
689                    (t->command == ACPI_EC_COMMAND_QUERY)) {
690                        ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
691                        t->rdata[t->ri++] = 0x00;
692                        ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
693                        ec_dbg_evt("Command(%s) completed by software",
694                                   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
695                        wakeup = true;
696                } else if ((status & ACPI_EC_FLAG_IBF) == 0) {
697                        acpi_ec_write_cmd(ec, t->command);
698                        ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
699                } else
700                        goto err;
701                goto out;
702        }
703err:
704        /*
705         * If SCI bit is set, then don't think it's a false IRQ
706         * otherwise will take a not handled IRQ as a false one.
707         */
708        if (!(status & ACPI_EC_FLAG_SCI)) {
709                if (in_interrupt() && t) {
710                        if (t->irq_count < ec_storm_threshold)
711                                ++t->irq_count;
712                        /* Allow triggering on 0 threshold */
713                        if (t->irq_count == ec_storm_threshold)
714                                acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
715                }
716        }
717out:
718        if (status & ACPI_EC_FLAG_SCI)
719                acpi_ec_submit_query(ec);
720        if (wakeup && in_interrupt())
721                wake_up(&ec->wait);
722}
723
724static void start_transaction(struct acpi_ec *ec)
725{
726        ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
727        ec->curr->flags = 0;
728}
729
730static int ec_guard(struct acpi_ec *ec)
731{
732        unsigned long guard = usecs_to_jiffies(ec->polling_guard);
733        unsigned long timeout = ec->timestamp + guard;
734
735        /* Ensure guarding period before polling EC status */
736        do {
737                if (ec->busy_polling) {
738                        /* Perform busy polling */
739                        if (ec_transaction_completed(ec))
740                                return 0;
741                        udelay(jiffies_to_usecs(guard));
742                } else {
743                        /*
744                         * Perform wait polling
745                         * 1. Wait the transaction to be completed by the
746                         *    GPE handler after the transaction enters
747                         *    ACPI_EC_COMMAND_POLL state.
748                         * 2. A special guarding logic is also required
749                         *    for event clearing mode "event" before the
750                         *    transaction enters ACPI_EC_COMMAND_POLL
751                         *    state.
752                         */
753                        if (!ec_transaction_polled(ec) &&
754                            !acpi_ec_guard_event(ec))
755                                break;
756                        if (wait_event_timeout(ec->wait,
757                                               ec_transaction_completed(ec),
758                                               guard))
759                                return 0;
760                }
761        } while (time_before(jiffies, timeout));
762        return -ETIME;
763}
764
765static int ec_poll(struct acpi_ec *ec)
766{
767        unsigned long flags;
768        int repeat = 5; /* number of command restarts */
769
770        while (repeat--) {
771                unsigned long delay = jiffies +
772                        msecs_to_jiffies(ec_delay);
773                do {
774                        if (!ec_guard(ec))
775                                return 0;
776                        spin_lock_irqsave(&ec->lock, flags);
777                        advance_transaction(ec);
778                        spin_unlock_irqrestore(&ec->lock, flags);
779                } while (time_before(jiffies, delay));
780                pr_debug("controller reset, restart transaction\n");
781                spin_lock_irqsave(&ec->lock, flags);
782                start_transaction(ec);
783                spin_unlock_irqrestore(&ec->lock, flags);
784        }
785        return -ETIME;
786}
787
788static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
789                                        struct transaction *t)
790{
791        unsigned long tmp;
792        int ret = 0;
793
794        /* start transaction */
795        spin_lock_irqsave(&ec->lock, tmp);
796        /* Enable GPE for command processing (IBF=0/OBF=1) */
797        if (!acpi_ec_submit_flushable_request(ec)) {
798                ret = -EINVAL;
799                goto unlock;
800        }
801        ec_dbg_ref(ec, "Increase command");
802        /* following two actions should be kept atomic */
803        ec->curr = t;
804        ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
805        start_transaction(ec);
806        spin_unlock_irqrestore(&ec->lock, tmp);
807
808        ret = ec_poll(ec);
809
810        spin_lock_irqsave(&ec->lock, tmp);
811        if (t->irq_count == ec_storm_threshold)
812                acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
813        ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
814        ec->curr = NULL;
815        /* Disable GPE for command processing (IBF=0/OBF=1) */
816        acpi_ec_complete_request(ec);
817        ec_dbg_ref(ec, "Decrease command");
818unlock:
819        spin_unlock_irqrestore(&ec->lock, tmp);
820        return ret;
821}
822
823static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
824{
825        int status;
826        u32 glk;
827
828        if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
829                return -EINVAL;
830        if (t->rdata)
831                memset(t->rdata, 0, t->rlen);
832
833        mutex_lock(&ec->mutex);
834        if (ec->global_lock) {
835                status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
836                if (ACPI_FAILURE(status)) {
837                        status = -ENODEV;
838                        goto unlock;
839                }
840        }
841
842        status = acpi_ec_transaction_unlocked(ec, t);
843
844        if (ec->global_lock)
845                acpi_release_global_lock(glk);
846unlock:
847        mutex_unlock(&ec->mutex);
848        return status;
849}
850
851static int acpi_ec_burst_enable(struct acpi_ec *ec)
852{
853        u8 d;
854        struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
855                                .wdata = NULL, .rdata = &d,
856                                .wlen = 0, .rlen = 1};
857
858        return acpi_ec_transaction(ec, &t);
859}
860
861static int acpi_ec_burst_disable(struct acpi_ec *ec)
862{
863        struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
864                                .wdata = NULL, .rdata = NULL,
865                                .wlen = 0, .rlen = 0};
866
867        return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
868                                acpi_ec_transaction(ec, &t) : 0;
869}
870
871static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
872{
873        int result;
874        u8 d;
875        struct transaction t = {.command = ACPI_EC_COMMAND_READ,
876                                .wdata = &address, .rdata = &d,
877                                .wlen = 1, .rlen = 1};
878
879        result = acpi_ec_transaction(ec, &t);
880        *data = d;
881        return result;
882}
883
884static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
885{
886        u8 wdata[2] = { address, data };
887        struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
888                                .wdata = wdata, .rdata = NULL,
889                                .wlen = 2, .rlen = 0};
890
891        return acpi_ec_transaction(ec, &t);
892}
893
894int ec_read(u8 addr, u8 *val)
895{
896        int err;
897        u8 temp_data;
898
899        if (!first_ec)
900                return -ENODEV;
901
902        err = acpi_ec_read(first_ec, addr, &temp_data);
903
904        if (!err) {
905                *val = temp_data;
906                return 0;
907        }
908        return err;
909}
910EXPORT_SYMBOL(ec_read);
911
912int ec_write(u8 addr, u8 val)
913{
914        int err;
915
916        if (!first_ec)
917                return -ENODEV;
918
919        err = acpi_ec_write(first_ec, addr, val);
920
921        return err;
922}
923EXPORT_SYMBOL(ec_write);
924
925int ec_transaction(u8 command,
926                   const u8 *wdata, unsigned wdata_len,
927                   u8 *rdata, unsigned rdata_len)
928{
929        struct transaction t = {.command = command,
930                                .wdata = wdata, .rdata = rdata,
931                                .wlen = wdata_len, .rlen = rdata_len};
932
933        if (!first_ec)
934                return -ENODEV;
935
936        return acpi_ec_transaction(first_ec, &t);
937}
938EXPORT_SYMBOL(ec_transaction);
939
940/* Get the handle to the EC device */
941acpi_handle ec_get_handle(void)
942{
943        if (!first_ec)
944                return NULL;
945        return first_ec->handle;
946}
947EXPORT_SYMBOL(ec_get_handle);
948
949static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
950{
951        unsigned long flags;
952
953        spin_lock_irqsave(&ec->lock, flags);
954        if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
955                ec_dbg_drv("Starting EC");
956                /* Enable GPE for event processing (SCI_EVT=1) */
957                if (!resuming) {
958                        acpi_ec_submit_request(ec);
959                        ec_dbg_ref(ec, "Increase driver");
960                }
961                ec_log_drv("EC started");
962        }
963        spin_unlock_irqrestore(&ec->lock, flags);
964}
965
966static bool acpi_ec_stopped(struct acpi_ec *ec)
967{
968        unsigned long flags;
969        bool flushed;
970
971        spin_lock_irqsave(&ec->lock, flags);
972        flushed = acpi_ec_flushed(ec);
973        spin_unlock_irqrestore(&ec->lock, flags);
974        return flushed;
975}
976
977static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
978{
979        unsigned long flags;
980
981        spin_lock_irqsave(&ec->lock, flags);
982        if (acpi_ec_started(ec)) {
983                ec_dbg_drv("Stopping EC");
984                set_bit(EC_FLAGS_STOPPED, &ec->flags);
985                spin_unlock_irqrestore(&ec->lock, flags);
986                wait_event(ec->wait, acpi_ec_stopped(ec));
987                spin_lock_irqsave(&ec->lock, flags);
988                /* Disable GPE for event processing (SCI_EVT=1) */
989                if (!suspending) {
990                        acpi_ec_complete_request(ec);
991                        ec_dbg_ref(ec, "Decrease driver");
992                } else if (!ec_freeze_events)
993                        __acpi_ec_disable_event(ec);
994                clear_bit(EC_FLAGS_STARTED, &ec->flags);
995                clear_bit(EC_FLAGS_STOPPED, &ec->flags);
996                ec_log_drv("EC stopped");
997        }
998        spin_unlock_irqrestore(&ec->lock, flags);
999}
1000
1001static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1002{
1003        unsigned long flags;
1004
1005        spin_lock_irqsave(&ec->lock, flags);
1006        ec->busy_polling = true;
1007        ec->polling_guard = 0;
1008        ec_log_drv("interrupt blocked");
1009        spin_unlock_irqrestore(&ec->lock, flags);
1010}
1011
1012static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1013{
1014        unsigned long flags;
1015
1016        spin_lock_irqsave(&ec->lock, flags);
1017        ec->busy_polling = ec_busy_polling;
1018        ec->polling_guard = ec_polling_guard;
1019        ec_log_drv("interrupt unblocked");
1020        spin_unlock_irqrestore(&ec->lock, flags);
1021}
1022
1023void acpi_ec_block_transactions(void)
1024{
1025        struct acpi_ec *ec = first_ec;
1026
1027        if (!ec)
1028                return;
1029
1030        mutex_lock(&ec->mutex);
1031        /* Prevent transactions from being carried out */
1032        acpi_ec_stop(ec, true);
1033        mutex_unlock(&ec->mutex);
1034}
1035
1036void acpi_ec_unblock_transactions(void)
1037{
1038        /*
1039         * Allow transactions to happen again (this function is called from
1040         * atomic context during wakeup, so we don't need to acquire the mutex).
1041         */
1042        if (first_ec)
1043                acpi_ec_start(first_ec, true);
1044}
1045
1046/* --------------------------------------------------------------------------
1047                                Event Management
1048   -------------------------------------------------------------------------- */
1049static struct acpi_ec_query_handler *
1050acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
1051{
1052        if (handler)
1053                kref_get(&handler->kref);
1054        return handler;
1055}
1056
1057static struct acpi_ec_query_handler *
1058acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1059{
1060        struct acpi_ec_query_handler *handler;
1061        bool found = false;
1062
1063        mutex_lock(&ec->mutex);
1064        list_for_each_entry(handler, &ec->list, node) {
1065                if (value == handler->query_bit) {
1066                        found = true;
1067                        break;
1068                }
1069        }
1070        mutex_unlock(&ec->mutex);
1071        return found ? acpi_ec_get_query_handler(handler) : NULL;
1072}
1073
1074static void acpi_ec_query_handler_release(struct kref *kref)
1075{
1076        struct acpi_ec_query_handler *handler =
1077                container_of(kref, struct acpi_ec_query_handler, kref);
1078
1079        kfree(handler);
1080}
1081
1082static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1083{
1084        kref_put(&handler->kref, acpi_ec_query_handler_release);
1085}
1086
1087int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1088                              acpi_handle handle, acpi_ec_query_func func,
1089                              void *data)
1090{
1091        struct acpi_ec_query_handler *handler =
1092            kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1093
1094        if (!handler)
1095                return -ENOMEM;
1096
1097        handler->query_bit = query_bit;
1098        handler->handle = handle;
1099        handler->func = func;
1100        handler->data = data;
1101        mutex_lock(&ec->mutex);
1102        kref_init(&handler->kref);
1103        list_add(&handler->node, &ec->list);
1104        mutex_unlock(&ec->mutex);
1105        return 0;
1106}
1107EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1108
1109static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1110                                          bool remove_all, u8 query_bit)
1111{
1112        struct acpi_ec_query_handler *handler, *tmp;
1113        LIST_HEAD(free_list);
1114
1115        mutex_lock(&ec->mutex);
1116        list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1117                if (remove_all || query_bit == handler->query_bit) {
1118                        list_del_init(&handler->node);
1119                        list_add(&handler->node, &free_list);
1120                }
1121        }
1122        mutex_unlock(&ec->mutex);
1123        list_for_each_entry_safe(handler, tmp, &free_list, node)
1124                acpi_ec_put_query_handler(handler);
1125}
1126
1127void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1128{
1129        acpi_ec_remove_query_handlers(ec, false, query_bit);
1130}
1131EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1132
1133static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1134{
1135        struct acpi_ec_query *q;
1136        struct transaction *t;
1137
1138        q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1139        if (!q)
1140                return NULL;
1141        INIT_WORK(&q->work, acpi_ec_event_processor);
1142        t = &q->transaction;
1143        t->command = ACPI_EC_COMMAND_QUERY;
1144        t->rdata = pval;
1145        t->rlen = 1;
1146        return q;
1147}
1148
1149static void acpi_ec_delete_query(struct acpi_ec_query *q)
1150{
1151        if (q) {
1152                if (q->handler)
1153                        acpi_ec_put_query_handler(q->handler);
1154                kfree(q);
1155        }
1156}
1157
1158static void acpi_ec_event_processor(struct work_struct *work)
1159{
1160        struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1161        struct acpi_ec_query_handler *handler = q->handler;
1162
1163        ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1164        if (handler->func)
1165                handler->func(handler->data);
1166        else if (handler->handle)
1167                acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1168        ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1169        acpi_ec_delete_query(q);
1170}
1171
1172static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1173{
1174        u8 value = 0;
1175        int result;
1176        struct acpi_ec_query *q;
1177
1178        q = acpi_ec_create_query(&value);
1179        if (!q)
1180                return -ENOMEM;
1181
1182        /*
1183         * Query the EC to find out which _Qxx method we need to evaluate.
1184         * Note that successful completion of the query causes the ACPI_EC_SCI
1185         * bit to be cleared (and thus clearing the interrupt source).
1186         */
1187        result = acpi_ec_transaction(ec, &q->transaction);
1188        if (!value)
1189                result = -ENODATA;
1190        if (result)
1191                goto err_exit;
1192
1193        q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1194        if (!q->handler) {
1195                result = -ENODATA;
1196                goto err_exit;
1197        }
1198
1199        /*
1200         * It is reported that _Qxx are evaluated in a parallel way on
1201         * Windows:
1202         * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1203         *
1204         * Put this log entry before schedule_work() in order to make
1205         * it appearing before any other log entries occurred during the
1206         * work queue execution.
1207         */
1208        ec_dbg_evt("Query(0x%02x) scheduled", value);
1209        if (!queue_work(ec_query_wq, &q->work)) {
1210                ec_dbg_evt("Query(0x%02x) overlapped", value);
1211                result = -EBUSY;
1212        }
1213
1214err_exit:
1215        if (result)
1216                acpi_ec_delete_query(q);
1217        if (data)
1218                *data = value;
1219        return result;
1220}
1221
1222static void acpi_ec_check_event(struct acpi_ec *ec)
1223{
1224        unsigned long flags;
1225
1226        if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1227                if (ec_guard(ec)) {
1228                        spin_lock_irqsave(&ec->lock, flags);
1229                        /*
1230                         * Take care of the SCI_EVT unless no one else is
1231                         * taking care of it.
1232                         */
1233                        if (!ec->curr)
1234                                advance_transaction(ec);
1235                        spin_unlock_irqrestore(&ec->lock, flags);
1236                }
1237        }
1238}
1239
1240static void acpi_ec_event_handler(struct work_struct *work)
1241{
1242        unsigned long flags;
1243        struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1244
1245        ec_dbg_evt("Event started");
1246
1247        spin_lock_irqsave(&ec->lock, flags);
1248        while (ec->nr_pending_queries) {
1249                spin_unlock_irqrestore(&ec->lock, flags);
1250                (void)acpi_ec_query(ec, NULL);
1251                spin_lock_irqsave(&ec->lock, flags);
1252                ec->nr_pending_queries--;
1253                /*
1254                 * Before exit, make sure that this work item can be
1255                 * scheduled again. There might be QR_EC failures, leaving
1256                 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1257                 * item from being scheduled again.
1258                 */
1259                if (!ec->nr_pending_queries) {
1260                        if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1261                            ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1262                                acpi_ec_complete_query(ec);
1263                }
1264        }
1265        spin_unlock_irqrestore(&ec->lock, flags);
1266
1267        ec_dbg_evt("Event stopped");
1268
1269        acpi_ec_check_event(ec);
1270}
1271
1272static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1273        u32 gpe_number, void *data)
1274{
1275        unsigned long flags;
1276        struct acpi_ec *ec = data;
1277
1278        spin_lock_irqsave(&ec->lock, flags);
1279        advance_transaction(ec);
1280        spin_unlock_irqrestore(&ec->lock, flags);
1281        return ACPI_INTERRUPT_HANDLED;
1282}
1283
1284/* --------------------------------------------------------------------------
1285 *                           Address Space Management
1286 * -------------------------------------------------------------------------- */
1287
1288static acpi_status
1289acpi_ec_space_handler(u32 function, acpi_physical_address address,
1290                      u32 bits, u64 *value64,
1291                      void *handler_context, void *region_context)
1292{
1293        struct acpi_ec *ec = handler_context;
1294        int result = 0, i, bytes = bits / 8;
1295        u8 *value = (u8 *)value64;
1296
1297        if ((address > 0xFF) || !value || !handler_context)
1298                return AE_BAD_PARAMETER;
1299
1300        if (function != ACPI_READ && function != ACPI_WRITE)
1301                return AE_BAD_PARAMETER;
1302
1303        if (ec->busy_polling || bits > 8)
1304                acpi_ec_burst_enable(ec);
1305
1306        for (i = 0; i < bytes; ++i, ++address, ++value)
1307                result = (function == ACPI_READ) ?
1308                        acpi_ec_read(ec, address, value) :
1309                        acpi_ec_write(ec, address, *value);
1310
1311        if (ec->busy_polling || bits > 8)
1312                acpi_ec_burst_disable(ec);
1313
1314        switch (result) {
1315        case -EINVAL:
1316                return AE_BAD_PARAMETER;
1317        case -ENODEV:
1318                return AE_NOT_FOUND;
1319        case -ETIME:
1320                return AE_TIME;
1321        default:
1322                return AE_OK;
1323        }
1324}
1325
1326/* --------------------------------------------------------------------------
1327 *                             Driver Interface
1328 * -------------------------------------------------------------------------- */
1329
1330static acpi_status
1331ec_parse_io_ports(struct acpi_resource *resource, void *context);
1332
1333static void acpi_ec_free(struct acpi_ec *ec)
1334{
1335        if (first_ec == ec)
1336                first_ec = NULL;
1337        if (boot_ec == ec)
1338                boot_ec = NULL;
1339        kfree(ec);
1340}
1341
1342static struct acpi_ec *acpi_ec_alloc(void)
1343{
1344        struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1345
1346        if (!ec)
1347                return NULL;
1348        mutex_init(&ec->mutex);
1349        init_waitqueue_head(&ec->wait);
1350        INIT_LIST_HEAD(&ec->list);
1351        spin_lock_init(&ec->lock);
1352        INIT_WORK(&ec->work, acpi_ec_event_handler);
1353        ec->timestamp = jiffies;
1354        ec->busy_polling = true;
1355        ec->polling_guard = 0;
1356        return ec;
1357}
1358
1359static acpi_status
1360acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1361                               void *context, void **return_value)
1362{
1363        char node_name[5];
1364        struct acpi_buffer buffer = { sizeof(node_name), node_name };
1365        struct acpi_ec *ec = context;
1366        int value = 0;
1367        acpi_status status;
1368
1369        status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1370
1371        if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1372                acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1373        return AE_OK;
1374}
1375
1376static acpi_status
1377ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1378{
1379        acpi_status status;
1380        unsigned long long tmp = 0;
1381        struct acpi_ec *ec = context;
1382
1383        /* clear addr values, ec_parse_io_ports depend on it */
1384        ec->command_addr = ec->data_addr = 0;
1385
1386        status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1387                                     ec_parse_io_ports, ec);
1388        if (ACPI_FAILURE(status))
1389                return status;
1390
1391        /* Get GPE bit assignment (EC events). */
1392        /* TODO: Add support for _GPE returning a package */
1393        status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1394        if (ACPI_FAILURE(status))
1395                return status;
1396        ec->gpe = tmp;
1397        /* Use the global lock for all EC transactions? */
1398        tmp = 0;
1399        acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1400        ec->global_lock = tmp;
1401        ec->handle = handle;
1402        return AE_CTRL_TERMINATE;
1403}
1404
1405/*
1406 * Note: This function returns an error code only when the address space
1407 *       handler is not installed, which means "not able to handle
1408 *       transactions".
1409 */
1410static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1411{
1412        acpi_status status;
1413
1414        acpi_ec_start(ec, false);
1415
1416        if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1417                acpi_ec_enter_noirq(ec);
1418                status = acpi_install_address_space_handler(ec->handle,
1419                                                            ACPI_ADR_SPACE_EC,
1420                                                            &acpi_ec_space_handler,
1421                                                            NULL, ec);
1422                if (ACPI_FAILURE(status)) {
1423                        if (status == AE_NOT_FOUND) {
1424                                /*
1425                                 * Maybe OS fails in evaluating the _REG
1426                                 * object. The AE_NOT_FOUND error will be
1427                                 * ignored and OS * continue to initialize
1428                                 * EC.
1429                                 */
1430                                pr_err("Fail in evaluating the _REG object"
1431                                        " of EC device. Broken bios is suspected.\n");
1432                        } else {
1433                                acpi_ec_stop(ec, false);
1434                                return -ENODEV;
1435                        }
1436                }
1437                set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1438        }
1439
1440        if (!handle_events)
1441                return 0;
1442
1443        if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1444                /* Find and register all query methods */
1445                acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1446                                    acpi_ec_register_query_methods,
1447                                    NULL, ec, NULL);
1448                set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1449        }
1450        if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1451                status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1452                                          ACPI_GPE_EDGE_TRIGGERED,
1453                                          &acpi_ec_gpe_handler, ec);
1454                /* This is not fatal as we can poll EC events */
1455                if (ACPI_SUCCESS(status)) {
1456                        set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1457                        acpi_ec_leave_noirq(ec);
1458                        if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1459                            ec->reference_count >= 1)
1460                                acpi_ec_enable_gpe(ec, true);
1461
1462                        /* EC is fully operational, allow queries */
1463                        acpi_ec_enable_event(ec);
1464                }
1465        }
1466
1467        return 0;
1468}
1469
1470static void ec_remove_handlers(struct acpi_ec *ec)
1471{
1472        if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1473                if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1474                                        ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1475                        pr_err("failed to remove space handler\n");
1476                clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1477        }
1478
1479        /*
1480         * Stops handling the EC transactions after removing the operation
1481         * region handler. This is required because _REG(DISCONNECT)
1482         * invoked during the removal can result in new EC transactions.
1483         *
1484         * Flushes the EC requests and thus disables the GPE before
1485         * removing the GPE handler. This is required by the current ACPICA
1486         * GPE core. ACPICA GPE core will automatically disable a GPE when
1487         * it is indicated but there is no way to handle it. So the drivers
1488         * must disable the GPEs prior to removing the GPE handlers.
1489         */
1490        acpi_ec_stop(ec, false);
1491
1492        if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1493                if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1494                                        &acpi_ec_gpe_handler)))
1495                        pr_err("failed to remove gpe handler\n");
1496                clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1497        }
1498        if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1499                acpi_ec_remove_query_handlers(ec, true, 0);
1500                clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1501        }
1502}
1503
1504static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1505{
1506        int ret;
1507
1508        ret = ec_install_handlers(ec, handle_events);
1509        if (ret)
1510                return ret;
1511
1512        /* First EC capable of handling transactions */
1513        if (!first_ec) {
1514                first_ec = ec;
1515                acpi_handle_info(first_ec->handle, "Used as first EC\n");
1516        }
1517
1518        acpi_handle_info(ec->handle,
1519                         "GPE=0x%lx, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1520                         ec->gpe, ec->command_addr, ec->data_addr);
1521        return ret;
1522}
1523
1524static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
1525                               bool handle_events, bool is_ecdt)
1526{
1527        int ret;
1528
1529        /*
1530         * Changing the ACPI handle results in a re-configuration of the
1531         * boot EC. And if it happens after the namespace initialization,
1532         * it causes _REG evaluations.
1533         */
1534        if (boot_ec && boot_ec->handle != handle)
1535                ec_remove_handlers(boot_ec);
1536
1537        /* Unset old boot EC */
1538        if (boot_ec != ec)
1539                acpi_ec_free(boot_ec);
1540
1541        /*
1542         * ECDT device creation is split into acpi_ec_ecdt_probe() and
1543         * acpi_ec_ecdt_start(). This function takes care of completing the
1544         * ECDT parsing logic as the handle update should be performed
1545         * between the installation/uninstallation of the handlers.
1546         */
1547        if (ec->handle != handle)
1548                ec->handle = handle;
1549
1550        ret = acpi_ec_setup(ec, handle_events);
1551        if (ret)
1552                return ret;
1553
1554        /* Set new boot EC */
1555        if (!boot_ec) {
1556                boot_ec = ec;
1557                boot_ec_is_ecdt = is_ecdt;
1558        }
1559
1560        acpi_handle_info(boot_ec->handle,
1561                         "Used as boot %s EC to handle transactions%s\n",
1562                         is_ecdt ? "ECDT" : "DSDT",
1563                         handle_events ? " and events" : "");
1564        return ret;
1565}
1566
1567static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1568{
1569        struct acpi_table_ecdt *ecdt_ptr;
1570        acpi_status status;
1571        acpi_handle handle;
1572
1573        status = acpi_get_table(ACPI_SIG_ECDT, 1,
1574                                (struct acpi_table_header **)&ecdt_ptr);
1575        if (ACPI_FAILURE(status))
1576                return false;
1577
1578        status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1579        if (ACPI_FAILURE(status))
1580                return false;
1581
1582        *phandle = handle;
1583        return true;
1584}
1585
1586static bool acpi_is_boot_ec(struct acpi_ec *ec)
1587{
1588        if (!boot_ec)
1589                return false;
1590        if (ec->handle == boot_ec->handle &&
1591            ec->gpe == boot_ec->gpe &&
1592            ec->command_addr == boot_ec->command_addr &&
1593            ec->data_addr == boot_ec->data_addr)
1594                return true;
1595        return false;
1596}
1597
1598static int acpi_ec_add(struct acpi_device *device)
1599{
1600        struct acpi_ec *ec = NULL;
1601        int ret;
1602
1603        strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1604        strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1605
1606        ec = acpi_ec_alloc();
1607        if (!ec)
1608                return -ENOMEM;
1609        if (ec_parse_device(device->handle, 0, ec, NULL) !=
1610                AE_CTRL_TERMINATE) {
1611                        ret = -EINVAL;
1612                        goto err_alloc;
1613        }
1614
1615        if (acpi_is_boot_ec(ec)) {
1616                boot_ec_is_ecdt = false;
1617                acpi_handle_debug(ec->handle, "duplicated.\n");
1618                acpi_ec_free(ec);
1619                ec = boot_ec;
1620                ret = acpi_config_boot_ec(ec, ec->handle, true, false);
1621        } else
1622                ret = acpi_ec_setup(ec, true);
1623        if (ret)
1624                goto err_query;
1625
1626        device->driver_data = ec;
1627
1628        ret = !!request_region(ec->data_addr, 1, "EC data");
1629        WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1630        ret = !!request_region(ec->command_addr, 1, "EC cmd");
1631        WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1632
1633        /* Reprobe devices depending on the EC */
1634        acpi_walk_dep_device_list(ec->handle);
1635        acpi_handle_debug(ec->handle, "enumerated.\n");
1636        return 0;
1637
1638err_query:
1639        if (ec != boot_ec)
1640                acpi_ec_remove_query_handlers(ec, true, 0);
1641err_alloc:
1642        if (ec != boot_ec)
1643                acpi_ec_free(ec);
1644        return ret;
1645}
1646
1647static int acpi_ec_remove(struct acpi_device *device)
1648{
1649        struct acpi_ec *ec;
1650
1651        if (!device)
1652                return -EINVAL;
1653
1654        ec = acpi_driver_data(device);
1655        release_region(ec->data_addr, 1);
1656        release_region(ec->command_addr, 1);
1657        device->driver_data = NULL;
1658        if (ec != boot_ec) {
1659                ec_remove_handlers(ec);
1660                acpi_ec_free(ec);
1661        }
1662        return 0;
1663}
1664
1665static acpi_status
1666ec_parse_io_ports(struct acpi_resource *resource, void *context)
1667{
1668        struct acpi_ec *ec = context;
1669
1670        if (resource->type != ACPI_RESOURCE_TYPE_IO)
1671                return AE_OK;
1672
1673        /*
1674         * The first address region returned is the data port, and
1675         * the second address region returned is the status/command
1676         * port.
1677         */
1678        if (ec->data_addr == 0)
1679                ec->data_addr = resource->data.io.minimum;
1680        else if (ec->command_addr == 0)
1681                ec->command_addr = resource->data.io.minimum;
1682        else
1683                return AE_CTRL_TERMINATE;
1684
1685        return AE_OK;
1686}
1687
1688static const struct acpi_device_id ec_device_ids[] = {
1689        {"PNP0C09", 0},
1690        {"", 0},
1691};
1692
1693int __init acpi_ec_dsdt_probe(void)
1694{
1695        acpi_status status;
1696        struct acpi_ec *ec;
1697        int ret;
1698
1699        ec = acpi_ec_alloc();
1700        if (!ec)
1701                return -ENOMEM;
1702        /*
1703         * At this point, the namespace is initialized, so start to find
1704         * the namespace objects.
1705         */
1706        status = acpi_get_devices(ec_device_ids[0].id,
1707                                  ec_parse_device, ec, NULL);
1708        if (ACPI_FAILURE(status) || !ec->handle) {
1709                ret = -ENODEV;
1710                goto error;
1711        }
1712        /*
1713         * When the DSDT EC is available, always re-configure boot EC to
1714         * have _REG evaluated. _REG can only be evaluated after the
1715         * namespace initialization.
1716         * At this point, the GPE is not fully initialized, so do not to
1717         * handle the events.
1718         */
1719        ret = acpi_config_boot_ec(ec, ec->handle, false, false);
1720error:
1721        if (ret)
1722                acpi_ec_free(ec);
1723        return ret;
1724}
1725
1726/*
1727 * If the DSDT EC is not functioning, we still need to prepare a fully
1728 * functioning ECDT EC first in order to handle the events.
1729 * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1730 */
1731int __init acpi_ec_ecdt_start(void)
1732{
1733        acpi_handle handle;
1734
1735        if (!boot_ec)
1736                return -ENODEV;
1737        /*
1738         * The DSDT EC should have already been started in
1739         * acpi_ec_add().
1740         */
1741        if (!boot_ec_is_ecdt)
1742                return -ENODEV;
1743
1744        /*
1745         * At this point, the namespace and the GPE is initialized, so
1746         * start to find the namespace objects and handle the events.
1747         */
1748        if (!acpi_ec_ecdt_get_handle(&handle))
1749                return -ENODEV;
1750        return acpi_config_boot_ec(boot_ec, handle, true, true);
1751}
1752
1753#if 0
1754/*
1755 * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1756 * set, for which case, we complete the QR_EC without issuing it to the
1757 * firmware.
1758 * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1759 * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1760 */
1761static int ec_flag_query_handshake(const struct dmi_system_id *id)
1762{
1763        pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1764        EC_FLAGS_QUERY_HANDSHAKE = 1;
1765        return 0;
1766}
1767#endif
1768
1769/*
1770 * On some hardware it is necessary to clear events accumulated by the EC during
1771 * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1772 * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1773 *
1774 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1775 *
1776 * Ideally, the EC should also be instructed NOT to accumulate events during
1777 * sleep (which Windows seems to do somehow), but the interface to control this
1778 * behaviour is not known at this time.
1779 *
1780 * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1781 * however it is very likely that other Samsung models are affected.
1782 *
1783 * On systems which don't accumulate _Q events during sleep, this extra check
1784 * should be harmless.
1785 */
1786static int ec_clear_on_resume(const struct dmi_system_id *id)
1787{
1788        pr_debug("Detected system needing EC poll on resume.\n");
1789        EC_FLAGS_CLEAR_ON_RESUME = 1;
1790        ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1791        return 0;
1792}
1793
1794/*
1795 * Some ECDTs contain wrong register addresses.
1796 * MSI MS-171F
1797 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1798 */
1799static int ec_correct_ecdt(const struct dmi_system_id *id)
1800{
1801        pr_debug("Detected system needing ECDT address correction.\n");
1802        EC_FLAGS_CORRECT_ECDT = 1;
1803        return 0;
1804}
1805
1806static struct dmi_system_id ec_dmi_table[] __initdata = {
1807        {
1808        ec_correct_ecdt, "MSI MS-171F", {
1809        DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1810        DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1811        {
1812        ec_clear_on_resume, "Samsung hardware", {
1813        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1814        {},
1815};
1816
1817int __init acpi_ec_ecdt_probe(void)
1818{
1819        int ret;
1820        acpi_status status;
1821        struct acpi_table_ecdt *ecdt_ptr;
1822        struct acpi_ec *ec;
1823
1824        ec = acpi_ec_alloc();
1825        if (!ec)
1826                return -ENOMEM;
1827        /*
1828         * Generate a boot ec context
1829         */
1830        dmi_check_system(ec_dmi_table);
1831        status = acpi_get_table(ACPI_SIG_ECDT, 1,
1832                                (struct acpi_table_header **)&ecdt_ptr);
1833        if (ACPI_FAILURE(status)) {
1834                ret = -ENODEV;
1835                goto error;
1836        }
1837
1838        if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1839                /*
1840                 * Asus X50GL:
1841                 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1842                 */
1843                ret = -ENODEV;
1844                goto error;
1845        }
1846
1847        if (EC_FLAGS_CORRECT_ECDT) {
1848                ec->command_addr = ecdt_ptr->data.address;
1849                ec->data_addr = ecdt_ptr->control.address;
1850        } else {
1851                ec->command_addr = ecdt_ptr->control.address;
1852                ec->data_addr = ecdt_ptr->data.address;
1853        }
1854        ec->gpe = ecdt_ptr->gpe;
1855
1856        /*
1857         * At this point, the namespace is not initialized, so do not find
1858         * the namespace objects, or handle the events.
1859         */
1860        ret = acpi_config_boot_ec(ec, ACPI_ROOT_OBJECT, false, true);
1861error:
1862        if (ret)
1863                acpi_ec_free(ec);
1864        return ret;
1865}
1866
1867#ifdef CONFIG_PM_SLEEP
1868static int acpi_ec_suspend_noirq(struct device *dev)
1869{
1870        struct acpi_ec *ec =
1871                acpi_driver_data(to_acpi_device(dev));
1872
1873        acpi_ec_enter_noirq(ec);
1874        return 0;
1875}
1876
1877static int acpi_ec_resume_noirq(struct device *dev)
1878{
1879        struct acpi_ec *ec =
1880                acpi_driver_data(to_acpi_device(dev));
1881
1882        acpi_ec_leave_noirq(ec);
1883        return 0;
1884}
1885
1886static int acpi_ec_suspend(struct device *dev)
1887{
1888        struct acpi_ec *ec =
1889                acpi_driver_data(to_acpi_device(dev));
1890
1891        if (ec_freeze_events)
1892                acpi_ec_disable_event(ec);
1893        return 0;
1894}
1895
1896static int acpi_ec_resume(struct device *dev)
1897{
1898        struct acpi_ec *ec =
1899                acpi_driver_data(to_acpi_device(dev));
1900
1901        acpi_ec_enable_event(ec);
1902        return 0;
1903}
1904#endif
1905
1906static const struct dev_pm_ops acpi_ec_pm = {
1907        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
1908        SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1909};
1910
1911static int param_set_event_clearing(const char *val, struct kernel_param *kp)
1912{
1913        int result = 0;
1914
1915        if (!strncmp(val, "status", sizeof("status") - 1)) {
1916                ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1917                pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1918        } else if (!strncmp(val, "query", sizeof("query") - 1)) {
1919                ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1920                pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1921        } else if (!strncmp(val, "event", sizeof("event") - 1)) {
1922                ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1923                pr_info("Assuming SCI_EVT clearing on event reads\n");
1924        } else
1925                result = -EINVAL;
1926        return result;
1927}
1928
1929static int param_get_event_clearing(char *buffer, struct kernel_param *kp)
1930{
1931        switch (ec_event_clearing) {
1932        case ACPI_EC_EVT_TIMING_STATUS:
1933                return sprintf(buffer, "status");
1934        case ACPI_EC_EVT_TIMING_QUERY:
1935                return sprintf(buffer, "query");
1936        case ACPI_EC_EVT_TIMING_EVENT:
1937                return sprintf(buffer, "event");
1938        default:
1939                return sprintf(buffer, "invalid");
1940        }
1941        return 0;
1942}
1943
1944module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
1945                  NULL, 0644);
1946MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
1947
1948static struct acpi_driver acpi_ec_driver = {
1949        .name = "ec",
1950        .class = ACPI_EC_CLASS,
1951        .ids = ec_device_ids,
1952        .ops = {
1953                .add = acpi_ec_add,
1954                .remove = acpi_ec_remove,
1955                },
1956        .drv.pm = &acpi_ec_pm,
1957};
1958
1959static inline int acpi_ec_query_init(void)
1960{
1961        if (!ec_query_wq) {
1962                ec_query_wq = alloc_workqueue("kec_query", 0,
1963                                              ec_max_queries);
1964                if (!ec_query_wq)
1965                        return -ENODEV;
1966        }
1967        return 0;
1968}
1969
1970static inline void acpi_ec_query_exit(void)
1971{
1972        if (ec_query_wq) {
1973                destroy_workqueue(ec_query_wq);
1974                ec_query_wq = NULL;
1975        }
1976}
1977
1978int __init acpi_ec_init(void)
1979{
1980        int result;
1981
1982        /* register workqueue for _Qxx evaluations */
1983        result = acpi_ec_query_init();
1984        if (result)
1985                goto err_exit;
1986        /* Now register the driver for the EC */
1987        result = acpi_bus_register_driver(&acpi_ec_driver);
1988        if (result)
1989                goto err_exit;
1990
1991err_exit:
1992        if (result)
1993                acpi_ec_query_exit();
1994        return result;
1995}
1996
1997/* EC driver currently not unloadable */
1998#if 0
1999static void __exit acpi_ec_exit(void)
2000{
2001
2002        acpi_bus_unregister_driver(&acpi_ec_driver);
2003        acpi_ec_query_exit();
2004}
2005#endif  /* 0 */
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