Root/drivers/input/input.c

1/*
2 * The input core
3 *
4 * Copyright (c) 1999-2002 Vojtech Pavlik
5 */
6
7/*
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published by
10 * the Free Software Foundation.
11 */
12
13#define pr_fmt(fmt) KBUILD_BASENAME ": " fmt
14
15#include <linux/init.h>
16#include <linux/types.h>
17#include <linux/idr.h>
18#include <linux/input/mt.h>
19#include <linux/module.h>
20#include <linux/slab.h>
21#include <linux/random.h>
22#include <linux/major.h>
23#include <linux/proc_fs.h>
24#include <linux/sched.h>
25#include <linux/seq_file.h>
26#include <linux/poll.h>
27#include <linux/device.h>
28#include <linux/mutex.h>
29#include <linux/rcupdate.h>
30#include "input-compat.h"
31
32MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
33MODULE_DESCRIPTION("Input core");
34MODULE_LICENSE("GPL");
35
36#define INPUT_MAX_CHAR_DEVICES 1024
37#define INPUT_FIRST_DYNAMIC_DEV 256
38static DEFINE_IDA(input_ida);
39
40static LIST_HEAD(input_dev_list);
41static LIST_HEAD(input_handler_list);
42
43/*
44 * input_mutex protects access to both input_dev_list and input_handler_list.
45 * This also causes input_[un]register_device and input_[un]register_handler
46 * be mutually exclusive which simplifies locking in drivers implementing
47 * input handlers.
48 */
49static DEFINE_MUTEX(input_mutex);
50
51static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };
52
53static inline int is_event_supported(unsigned int code,
54                     unsigned long *bm, unsigned int max)
55{
56    return code <= max && test_bit(code, bm);
57}
58
59static int input_defuzz_abs_event(int value, int old_val, int fuzz)
60{
61    if (fuzz) {
62        if (value > old_val - fuzz / 2 && value < old_val + fuzz / 2)
63            return old_val;
64
65        if (value > old_val - fuzz && value < old_val + fuzz)
66            return (old_val * 3 + value) / 4;
67
68        if (value > old_val - fuzz * 2 && value < old_val + fuzz * 2)
69            return (old_val + value) / 2;
70    }
71
72    return value;
73}
74
75static void input_start_autorepeat(struct input_dev *dev, int code)
76{
77    if (test_bit(EV_REP, dev->evbit) &&
78        dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
79        dev->timer.data) {
80        dev->repeat_key = code;
81        mod_timer(&dev->timer,
82              jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
83    }
84}
85
86static void input_stop_autorepeat(struct input_dev *dev)
87{
88    del_timer(&dev->timer);
89}
90
91/*
92 * Pass event first through all filters and then, if event has not been
93 * filtered out, through all open handles. This function is called with
94 * dev->event_lock held and interrupts disabled.
95 */
96static unsigned int input_to_handler(struct input_handle *handle,
97            struct input_value *vals, unsigned int count)
98{
99    struct input_handler *handler = handle->handler;
100    struct input_value *end = vals;
101    struct input_value *v;
102
103    for (v = vals; v != vals + count; v++) {
104        if (handler->filter &&
105            handler->filter(handle, v->type, v->code, v->value))
106            continue;
107        if (end != v)
108            *end = *v;
109        end++;
110    }
111
112    count = end - vals;
113    if (!count)
114        return 0;
115
116    if (handler->events)
117        handler->events(handle, vals, count);
118    else if (handler->event)
119        for (v = vals; v != end; v++)
120            handler->event(handle, v->type, v->code, v->value);
121
122    return count;
123}
124
125/*
126 * Pass values first through all filters and then, if event has not been
127 * filtered out, through all open handles. This function is called with
128 * dev->event_lock held and interrupts disabled.
129 */
130static void input_pass_values(struct input_dev *dev,
131                  struct input_value *vals, unsigned int count)
132{
133    struct input_handle *handle;
134    struct input_value *v;
135
136    if (!count)
137        return;
138
139    rcu_read_lock();
140
141    handle = rcu_dereference(dev->grab);
142    if (handle) {
143        count = input_to_handler(handle, vals, count);
144    } else {
145        list_for_each_entry_rcu(handle, &dev->h_list, d_node)
146            if (handle->open)
147                count = input_to_handler(handle, vals, count);
148    }
149
150    rcu_read_unlock();
151
152    add_input_randomness(vals->type, vals->code, vals->value);
153
154    /* trigger auto repeat for key events */
155    for (v = vals; v != vals + count; v++) {
156        if (v->type == EV_KEY && v->value != 2) {
157            if (v->value)
158                input_start_autorepeat(dev, v->code);
159            else
160                input_stop_autorepeat(dev);
161        }
162    }
163}
164
165static void input_pass_event(struct input_dev *dev,
166                 unsigned int type, unsigned int code, int value)
167{
168    struct input_value vals[] = { { type, code, value } };
169
170    input_pass_values(dev, vals, ARRAY_SIZE(vals));
171}
172
173/*
174 * Generate software autorepeat event. Note that we take
175 * dev->event_lock here to avoid racing with input_event
176 * which may cause keys get "stuck".
177 */
178static void input_repeat_key(unsigned long data)
179{
180    struct input_dev *dev = (void *) data;
181    unsigned long flags;
182
183    spin_lock_irqsave(&dev->event_lock, flags);
184
185    if (test_bit(dev->repeat_key, dev->key) &&
186        is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
187        struct input_value vals[] = {
188            { EV_KEY, dev->repeat_key, 2 },
189            input_value_sync
190        };
191
192        input_pass_values(dev, vals, ARRAY_SIZE(vals));
193
194        if (dev->rep[REP_PERIOD])
195            mod_timer(&dev->timer, jiffies +
196                    msecs_to_jiffies(dev->rep[REP_PERIOD]));
197    }
198
199    spin_unlock_irqrestore(&dev->event_lock, flags);
200}
201
202#define INPUT_IGNORE_EVENT 0
203#define INPUT_PASS_TO_HANDLERS 1
204#define INPUT_PASS_TO_DEVICE 2
205#define INPUT_SLOT 4
206#define INPUT_FLUSH 8
207#define INPUT_PASS_TO_ALL (INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
208
209static int input_handle_abs_event(struct input_dev *dev,
210                  unsigned int code, int *pval)
211{
212    struct input_mt *mt = dev->mt;
213    bool is_mt_event;
214    int *pold;
215
216    if (code == ABS_MT_SLOT) {
217        /*
218         * "Stage" the event; we'll flush it later, when we
219         * get actual touch data.
220         */
221        if (mt && *pval >= 0 && *pval < mt->num_slots)
222            mt->slot = *pval;
223
224        return INPUT_IGNORE_EVENT;
225    }
226
227    is_mt_event = input_is_mt_value(code);
228
229    if (!is_mt_event) {
230        pold = &dev->absinfo[code].value;
231    } else if (mt) {
232        pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
233    } else {
234        /*
235         * Bypass filtering for multi-touch events when
236         * not employing slots.
237         */
238        pold = NULL;
239    }
240
241    if (pold) {
242        *pval = input_defuzz_abs_event(*pval, *pold,
243                        dev->absinfo[code].fuzz);
244        if (*pold == *pval)
245            return INPUT_IGNORE_EVENT;
246
247        *pold = *pval;
248    }
249
250    /* Flush pending "slot" event */
251    if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
252        input_abs_set_val(dev, ABS_MT_SLOT, mt->slot);
253        return INPUT_PASS_TO_HANDLERS | INPUT_SLOT;
254    }
255
256    return INPUT_PASS_TO_HANDLERS;
257}
258
259static int input_get_disposition(struct input_dev *dev,
260              unsigned int type, unsigned int code, int value)
261{
262    int disposition = INPUT_IGNORE_EVENT;
263
264    switch (type) {
265
266    case EV_SYN:
267        switch (code) {
268        case SYN_CONFIG:
269            disposition = INPUT_PASS_TO_ALL;
270            break;
271
272        case SYN_REPORT:
273            disposition = INPUT_PASS_TO_HANDLERS | INPUT_FLUSH;
274            break;
275        case SYN_MT_REPORT:
276            disposition = INPUT_PASS_TO_HANDLERS;
277            break;
278        }
279        break;
280
281    case EV_KEY:
282        if (is_event_supported(code, dev->keybit, KEY_MAX)) {
283
284            /* auto-repeat bypasses state updates */
285            if (value == 2) {
286                disposition = INPUT_PASS_TO_HANDLERS;
287                break;
288            }
289
290            if (!!test_bit(code, dev->key) != !!value) {
291
292                __change_bit(code, dev->key);
293                disposition = INPUT_PASS_TO_HANDLERS;
294            }
295        }
296        break;
297
298    case EV_SW:
299        if (is_event_supported(code, dev->swbit, SW_MAX) &&
300            !!test_bit(code, dev->sw) != !!value) {
301
302            __change_bit(code, dev->sw);
303            disposition = INPUT_PASS_TO_HANDLERS;
304        }
305        break;
306
307    case EV_ABS:
308        if (is_event_supported(code, dev->absbit, ABS_MAX))
309            disposition = input_handle_abs_event(dev, code, &value);
310
311        break;
312
313    case EV_REL:
314        if (is_event_supported(code, dev->relbit, REL_MAX) && value)
315            disposition = INPUT_PASS_TO_HANDLERS;
316
317        break;
318
319    case EV_MSC:
320        if (is_event_supported(code, dev->mscbit, MSC_MAX))
321            disposition = INPUT_PASS_TO_ALL;
322
323        break;
324
325    case EV_LED:
326        if (is_event_supported(code, dev->ledbit, LED_MAX) &&
327            !!test_bit(code, dev->led) != !!value) {
328
329            __change_bit(code, dev->led);
330            disposition = INPUT_PASS_TO_ALL;
331        }
332        break;
333
334    case EV_SND:
335        if (is_event_supported(code, dev->sndbit, SND_MAX)) {
336
337            if (!!test_bit(code, dev->snd) != !!value)
338                __change_bit(code, dev->snd);
339            disposition = INPUT_PASS_TO_ALL;
340        }
341        break;
342
343    case EV_REP:
344        if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
345            dev->rep[code] = value;
346            disposition = INPUT_PASS_TO_ALL;
347        }
348        break;
349
350    case EV_FF:
351        if (value >= 0)
352            disposition = INPUT_PASS_TO_ALL;
353        break;
354
355    case EV_PWR:
356        disposition = INPUT_PASS_TO_ALL;
357        break;
358    }
359
360    return disposition;
361}
362
363static void input_handle_event(struct input_dev *dev,
364                   unsigned int type, unsigned int code, int value)
365{
366    int disposition;
367
368    disposition = input_get_disposition(dev, type, code, value);
369
370    if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event)
371        dev->event(dev, type, code, value);
372
373    if (!dev->vals)
374        return;
375
376    if (disposition & INPUT_PASS_TO_HANDLERS) {
377        struct input_value *v;
378
379        if (disposition & INPUT_SLOT) {
380            v = &dev->vals[dev->num_vals++];
381            v->type = EV_ABS;
382            v->code = ABS_MT_SLOT;
383            v->value = dev->mt->slot;
384        }
385
386        v = &dev->vals[dev->num_vals++];
387        v->type = type;
388        v->code = code;
389        v->value = value;
390    }
391
392    if (disposition & INPUT_FLUSH) {
393        if (dev->num_vals >= 2)
394            input_pass_values(dev, dev->vals, dev->num_vals);
395        dev->num_vals = 0;
396    } else if (dev->num_vals >= dev->max_vals - 2) {
397        dev->vals[dev->num_vals++] = input_value_sync;
398        input_pass_values(dev, dev->vals, dev->num_vals);
399        dev->num_vals = 0;
400    }
401
402}
403
404/**
405 * input_event() - report new input event
406 * @dev: device that generated the event
407 * @type: type of the event
408 * @code: event code
409 * @value: value of the event
410 *
411 * This function should be used by drivers implementing various input
412 * devices to report input events. See also input_inject_event().
413 *
414 * NOTE: input_event() may be safely used right after input device was
415 * allocated with input_allocate_device(), even before it is registered
416 * with input_register_device(), but the event will not reach any of the
417 * input handlers. Such early invocation of input_event() may be used
418 * to 'seed' initial state of a switch or initial position of absolute
419 * axis, etc.
420 */
421void input_event(struct input_dev *dev,
422         unsigned int type, unsigned int code, int value)
423{
424    unsigned long flags;
425
426    if (is_event_supported(type, dev->evbit, EV_MAX)) {
427
428        spin_lock_irqsave(&dev->event_lock, flags);
429        input_handle_event(dev, type, code, value);
430        spin_unlock_irqrestore(&dev->event_lock, flags);
431    }
432}
433EXPORT_SYMBOL(input_event);
434
435/**
436 * input_inject_event() - send input event from input handler
437 * @handle: input handle to send event through
438 * @type: type of the event
439 * @code: event code
440 * @value: value of the event
441 *
442 * Similar to input_event() but will ignore event if device is
443 * "grabbed" and handle injecting event is not the one that owns
444 * the device.
445 */
446void input_inject_event(struct input_handle *handle,
447            unsigned int type, unsigned int code, int value)
448{
449    struct input_dev *dev = handle->dev;
450    struct input_handle *grab;
451    unsigned long flags;
452
453    if (is_event_supported(type, dev->evbit, EV_MAX)) {
454        spin_lock_irqsave(&dev->event_lock, flags);
455
456        rcu_read_lock();
457        grab = rcu_dereference(dev->grab);
458        if (!grab || grab == handle)
459            input_handle_event(dev, type, code, value);
460        rcu_read_unlock();
461
462        spin_unlock_irqrestore(&dev->event_lock, flags);
463    }
464}
465EXPORT_SYMBOL(input_inject_event);
466
467/**
468 * input_alloc_absinfo - allocates array of input_absinfo structs
469 * @dev: the input device emitting absolute events
470 *
471 * If the absinfo struct the caller asked for is already allocated, this
472 * functions will not do anything.
473 */
474void input_alloc_absinfo(struct input_dev *dev)
475{
476    if (!dev->absinfo)
477        dev->absinfo = kcalloc(ABS_CNT, sizeof(struct input_absinfo),
478                    GFP_KERNEL);
479
480    WARN(!dev->absinfo, "%s(): kcalloc() failed?\n", __func__);
481}
482EXPORT_SYMBOL(input_alloc_absinfo);
483
484void input_set_abs_params(struct input_dev *dev, unsigned int axis,
485              int min, int max, int fuzz, int flat)
486{
487    struct input_absinfo *absinfo;
488
489    input_alloc_absinfo(dev);
490    if (!dev->absinfo)
491        return;
492
493    absinfo = &dev->absinfo[axis];
494    absinfo->minimum = min;
495    absinfo->maximum = max;
496    absinfo->fuzz = fuzz;
497    absinfo->flat = flat;
498
499    dev->absbit[BIT_WORD(axis)] |= BIT_MASK(axis);
500}
501EXPORT_SYMBOL(input_set_abs_params);
502
503
504/**
505 * input_grab_device - grabs device for exclusive use
506 * @handle: input handle that wants to own the device
507 *
508 * When a device is grabbed by an input handle all events generated by
509 * the device are delivered only to this handle. Also events injected
510 * by other input handles are ignored while device is grabbed.
511 */
512int input_grab_device(struct input_handle *handle)
513{
514    struct input_dev *dev = handle->dev;
515    int retval;
516
517    retval = mutex_lock_interruptible(&dev->mutex);
518    if (retval)
519        return retval;
520
521    if (dev->grab) {
522        retval = -EBUSY;
523        goto out;
524    }
525
526    rcu_assign_pointer(dev->grab, handle);
527
528 out:
529    mutex_unlock(&dev->mutex);
530    return retval;
531}
532EXPORT_SYMBOL(input_grab_device);
533
534static void __input_release_device(struct input_handle *handle)
535{
536    struct input_dev *dev = handle->dev;
537    struct input_handle *grabber;
538
539    grabber = rcu_dereference_protected(dev->grab,
540                        lockdep_is_held(&dev->mutex));
541    if (grabber == handle) {
542        rcu_assign_pointer(dev->grab, NULL);
543        /* Make sure input_pass_event() notices that grab is gone */
544        synchronize_rcu();
545
546        list_for_each_entry(handle, &dev->h_list, d_node)
547            if (handle->open && handle->handler->start)
548                handle->handler->start(handle);
549    }
550}
551
552/**
553 * input_release_device - release previously grabbed device
554 * @handle: input handle that owns the device
555 *
556 * Releases previously grabbed device so that other input handles can
557 * start receiving input events. Upon release all handlers attached
558 * to the device have their start() method called so they have a change
559 * to synchronize device state with the rest of the system.
560 */
561void input_release_device(struct input_handle *handle)
562{
563    struct input_dev *dev = handle->dev;
564
565    mutex_lock(&dev->mutex);
566    __input_release_device(handle);
567    mutex_unlock(&dev->mutex);
568}
569EXPORT_SYMBOL(input_release_device);
570
571/**
572 * input_open_device - open input device
573 * @handle: handle through which device is being accessed
574 *
575 * This function should be called by input handlers when they
576 * want to start receive events from given input device.
577 */
578int input_open_device(struct input_handle *handle)
579{
580    struct input_dev *dev = handle->dev;
581    int retval;
582
583    retval = mutex_lock_interruptible(&dev->mutex);
584    if (retval)
585        return retval;
586
587    if (dev->going_away) {
588        retval = -ENODEV;
589        goto out;
590    }
591
592    handle->open++;
593
594    if (!dev->users++ && dev->open)
595        retval = dev->open(dev);
596
597    if (retval) {
598        dev->users--;
599        if (!--handle->open) {
600            /*
601             * Make sure we are not delivering any more events
602             * through this handle
603             */
604            synchronize_rcu();
605        }
606    }
607
608 out:
609    mutex_unlock(&dev->mutex);
610    return retval;
611}
612EXPORT_SYMBOL(input_open_device);
613
614int input_flush_device(struct input_handle *handle, struct file *file)
615{
616    struct input_dev *dev = handle->dev;
617    int retval;
618
619    retval = mutex_lock_interruptible(&dev->mutex);
620    if (retval)
621        return retval;
622
623    if (dev->flush)
624        retval = dev->flush(dev, file);
625
626    mutex_unlock(&dev->mutex);
627    return retval;
628}
629EXPORT_SYMBOL(input_flush_device);
630
631/**
632 * input_close_device - close input device
633 * @handle: handle through which device is being accessed
634 *
635 * This function should be called by input handlers when they
636 * want to stop receive events from given input device.
637 */
638void input_close_device(struct input_handle *handle)
639{
640    struct input_dev *dev = handle->dev;
641
642    mutex_lock(&dev->mutex);
643
644    __input_release_device(handle);
645
646    if (!--dev->users && dev->close)
647        dev->close(dev);
648
649    if (!--handle->open) {
650        /*
651         * synchronize_rcu() makes sure that input_pass_event()
652         * completed and that no more input events are delivered
653         * through this handle
654         */
655        synchronize_rcu();
656    }
657
658    mutex_unlock(&dev->mutex);
659}
660EXPORT_SYMBOL(input_close_device);
661
662/*
663 * Simulate keyup events for all keys that are marked as pressed.
664 * The function must be called with dev->event_lock held.
665 */
666static void input_dev_release_keys(struct input_dev *dev)
667{
668    int code;
669
670    if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
671        for (code = 0; code <= KEY_MAX; code++) {
672            if (is_event_supported(code, dev->keybit, KEY_MAX) &&
673                __test_and_clear_bit(code, dev->key)) {
674                input_pass_event(dev, EV_KEY, code, 0);
675            }
676        }
677        input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
678    }
679}
680
681/*
682 * Prepare device for unregistering
683 */
684static void input_disconnect_device(struct input_dev *dev)
685{
686    struct input_handle *handle;
687
688    /*
689     * Mark device as going away. Note that we take dev->mutex here
690     * not to protect access to dev->going_away but rather to ensure
691     * that there are no threads in the middle of input_open_device()
692     */
693    mutex_lock(&dev->mutex);
694    dev->going_away = true;
695    mutex_unlock(&dev->mutex);
696
697    spin_lock_irq(&dev->event_lock);
698
699    /*
700     * Simulate keyup events for all pressed keys so that handlers
701     * are not left with "stuck" keys. The driver may continue
702     * generate events even after we done here but they will not
703     * reach any handlers.
704     */
705    input_dev_release_keys(dev);
706
707    list_for_each_entry(handle, &dev->h_list, d_node)
708        handle->open = 0;
709
710    spin_unlock_irq(&dev->event_lock);
711}
712
713/**
714 * input_scancode_to_scalar() - converts scancode in &struct input_keymap_entry
715 * @ke: keymap entry containing scancode to be converted.
716 * @scancode: pointer to the location where converted scancode should
717 * be stored.
718 *
719 * This function is used to convert scancode stored in &struct keymap_entry
720 * into scalar form understood by legacy keymap handling methods. These
721 * methods expect scancodes to be represented as 'unsigned int'.
722 */
723int input_scancode_to_scalar(const struct input_keymap_entry *ke,
724                 unsigned int *scancode)
725{
726    switch (ke->len) {
727    case 1:
728        *scancode = *((u8 *)ke->scancode);
729        break;
730
731    case 2:
732        *scancode = *((u16 *)ke->scancode);
733        break;
734
735    case 4:
736        *scancode = *((u32 *)ke->scancode);
737        break;
738
739    default:
740        return -EINVAL;
741    }
742
743    return 0;
744}
745EXPORT_SYMBOL(input_scancode_to_scalar);
746
747/*
748 * Those routines handle the default case where no [gs]etkeycode() is
749 * defined. In this case, an array indexed by the scancode is used.
750 */
751
752static unsigned int input_fetch_keycode(struct input_dev *dev,
753                    unsigned int index)
754{
755    switch (dev->keycodesize) {
756    case 1:
757        return ((u8 *)dev->keycode)[index];
758
759    case 2:
760        return ((u16 *)dev->keycode)[index];
761
762    default:
763        return ((u32 *)dev->keycode)[index];
764    }
765}
766
767static int input_default_getkeycode(struct input_dev *dev,
768                    struct input_keymap_entry *ke)
769{
770    unsigned int index;
771    int error;
772
773    if (!dev->keycodesize)
774        return -EINVAL;
775
776    if (ke->flags & INPUT_KEYMAP_BY_INDEX)
777        index = ke->index;
778    else {
779        error = input_scancode_to_scalar(ke, &index);
780        if (error)
781            return error;
782    }
783
784    if (index >= dev->keycodemax)
785        return -EINVAL;
786
787    ke->keycode = input_fetch_keycode(dev, index);
788    ke->index = index;
789    ke->len = sizeof(index);
790    memcpy(ke->scancode, &index, sizeof(index));
791
792    return 0;
793}
794
795static int input_default_setkeycode(struct input_dev *dev,
796                    const struct input_keymap_entry *ke,
797                    unsigned int *old_keycode)
798{
799    unsigned int index;
800    int error;
801    int i;
802
803    if (!dev->keycodesize)
804        return -EINVAL;
805
806    if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
807        index = ke->index;
808    } else {
809        error = input_scancode_to_scalar(ke, &index);
810        if (error)
811            return error;
812    }
813
814    if (index >= dev->keycodemax)
815        return -EINVAL;
816
817    if (dev->keycodesize < sizeof(ke->keycode) &&
818            (ke->keycode >> (dev->keycodesize * 8)))
819        return -EINVAL;
820
821    switch (dev->keycodesize) {
822        case 1: {
823            u8 *k = (u8 *)dev->keycode;
824            *old_keycode = k[index];
825            k[index] = ke->keycode;
826            break;
827        }
828        case 2: {
829            u16 *k = (u16 *)dev->keycode;
830            *old_keycode = k[index];
831            k[index] = ke->keycode;
832            break;
833        }
834        default: {
835            u32 *k = (u32 *)dev->keycode;
836            *old_keycode = k[index];
837            k[index] = ke->keycode;
838            break;
839        }
840    }
841
842    __clear_bit(*old_keycode, dev->keybit);
843    __set_bit(ke->keycode, dev->keybit);
844
845    for (i = 0; i < dev->keycodemax; i++) {
846        if (input_fetch_keycode(dev, i) == *old_keycode) {
847            __set_bit(*old_keycode, dev->keybit);
848            break; /* Setting the bit twice is useless, so break */
849        }
850    }
851
852    return 0;
853}
854
855/**
856 * input_get_keycode - retrieve keycode currently mapped to a given scancode
857 * @dev: input device which keymap is being queried
858 * @ke: keymap entry
859 *
860 * This function should be called by anyone interested in retrieving current
861 * keymap. Presently evdev handlers use it.
862 */
863int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke)
864{
865    unsigned long flags;
866    int retval;
867
868    spin_lock_irqsave(&dev->event_lock, flags);
869    retval = dev->getkeycode(dev, ke);
870    spin_unlock_irqrestore(&dev->event_lock, flags);
871
872    return retval;
873}
874EXPORT_SYMBOL(input_get_keycode);
875
876/**
877 * input_set_keycode - attribute a keycode to a given scancode
878 * @dev: input device which keymap is being updated
879 * @ke: new keymap entry
880 *
881 * This function should be called by anyone needing to update current
882 * keymap. Presently keyboard and evdev handlers use it.
883 */
884int input_set_keycode(struct input_dev *dev,
885              const struct input_keymap_entry *ke)
886{
887    unsigned long flags;
888    unsigned int old_keycode;
889    int retval;
890
891    if (ke->keycode > KEY_MAX)
892        return -EINVAL;
893
894    spin_lock_irqsave(&dev->event_lock, flags);
895
896    retval = dev->setkeycode(dev, ke, &old_keycode);
897    if (retval)
898        goto out;
899
900    /* Make sure KEY_RESERVED did not get enabled. */
901    __clear_bit(KEY_RESERVED, dev->keybit);
902
903    /*
904     * Simulate keyup event if keycode is not present
905     * in the keymap anymore
906     */
907    if (test_bit(EV_KEY, dev->evbit) &&
908        !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
909        __test_and_clear_bit(old_keycode, dev->key)) {
910        struct input_value vals[] = {
911            { EV_KEY, old_keycode, 0 },
912            input_value_sync
913        };
914
915        input_pass_values(dev, vals, ARRAY_SIZE(vals));
916    }
917
918 out:
919    spin_unlock_irqrestore(&dev->event_lock, flags);
920
921    return retval;
922}
923EXPORT_SYMBOL(input_set_keycode);
924
925static const struct input_device_id *input_match_device(struct input_handler *handler,
926                            struct input_dev *dev)
927{
928    const struct input_device_id *id;
929
930    for (id = handler->id_table; id->flags || id->driver_info; id++) {
931
932        if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
933            if (id->bustype != dev->id.bustype)
934                continue;
935
936        if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
937            if (id->vendor != dev->id.vendor)
938                continue;
939
940        if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
941            if (id->product != dev->id.product)
942                continue;
943
944        if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
945            if (id->version != dev->id.version)
946                continue;
947
948        if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX))
949            continue;
950
951        if (!bitmap_subset(id->keybit, dev->keybit, KEY_MAX))
952            continue;
953
954        if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
955            continue;
956
957        if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
958            continue;
959
960        if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
961            continue;
962
963        if (!bitmap_subset(id->ledbit, dev->ledbit, LED_MAX))
964            continue;
965
966        if (!bitmap_subset(id->sndbit, dev->sndbit, SND_MAX))
967            continue;
968
969        if (!bitmap_subset(id->ffbit, dev->ffbit, FF_MAX))
970            continue;
971
972        if (!bitmap_subset(id->swbit, dev->swbit, SW_MAX))
973            continue;
974
975        if (!handler->match || handler->match(handler, dev))
976            return id;
977    }
978
979    return NULL;
980}
981
982static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
983{
984    const struct input_device_id *id;
985    int error;
986
987    id = input_match_device(handler, dev);
988    if (!id)
989        return -ENODEV;
990
991    error = handler->connect(handler, dev, id);
992    if (error && error != -ENODEV)
993        pr_err("failed to attach handler %s to device %s, error: %d\n",
994               handler->name, kobject_name(&dev->dev.kobj), error);
995
996    return error;
997}
998
999#ifdef CONFIG_COMPAT
1000
1001static int input_bits_to_string(char *buf, int buf_size,
1002                unsigned long bits, bool skip_empty)
1003{
1004    int len = 0;
1005
1006    if (INPUT_COMPAT_TEST) {
1007        u32 dword = bits >> 32;
1008        if (dword || !skip_empty)
1009            len += snprintf(buf, buf_size, "%x ", dword);
1010
1011        dword = bits & 0xffffffffUL;
1012        if (dword || !skip_empty || len)
1013            len += snprintf(buf + len, max(buf_size - len, 0),
1014                    "%x", dword);
1015    } else {
1016        if (bits || !skip_empty)
1017            len += snprintf(buf, buf_size, "%lx", bits);
1018    }
1019
1020    return len;
1021}
1022
1023#else /* !CONFIG_COMPAT */
1024
1025static int input_bits_to_string(char *buf, int buf_size,
1026                unsigned long bits, bool skip_empty)
1027{
1028    return bits || !skip_empty ?
1029        snprintf(buf, buf_size, "%lx", bits) : 0;
1030}
1031
1032#endif
1033
1034#ifdef CONFIG_PROC_FS
1035
1036static struct proc_dir_entry *proc_bus_input_dir;
1037static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
1038static int input_devices_state;
1039
1040static inline void input_wakeup_procfs_readers(void)
1041{
1042    input_devices_state++;
1043    wake_up(&input_devices_poll_wait);
1044}
1045
1046static unsigned int input_proc_devices_poll(struct file *file, poll_table *wait)
1047{
1048    poll_wait(file, &input_devices_poll_wait, wait);
1049    if (file->f_version != input_devices_state) {
1050        file->f_version = input_devices_state;
1051        return POLLIN | POLLRDNORM;
1052    }
1053
1054    return 0;
1055}
1056
1057union input_seq_state {
1058    struct {
1059        unsigned short pos;
1060        bool mutex_acquired;
1061    };
1062    void *p;
1063};
1064
1065static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
1066{
1067    union input_seq_state *state = (union input_seq_state *)&seq->private;
1068    int error;
1069
1070    /* We need to fit into seq->private pointer */
1071    BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
1072
1073    error = mutex_lock_interruptible(&input_mutex);
1074    if (error) {
1075        state->mutex_acquired = false;
1076        return ERR_PTR(error);
1077    }
1078
1079    state->mutex_acquired = true;
1080
1081    return seq_list_start(&input_dev_list, *pos);
1082}
1083
1084static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1085{
1086    return seq_list_next(v, &input_dev_list, pos);
1087}
1088
1089static void input_seq_stop(struct seq_file *seq, void *v)
1090{
1091    union input_seq_state *state = (union input_seq_state *)&seq->private;
1092
1093    if (state->mutex_acquired)
1094        mutex_unlock(&input_mutex);
1095}
1096
1097static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
1098                   unsigned long *bitmap, int max)
1099{
1100    int i;
1101    bool skip_empty = true;
1102    char buf[18];
1103
1104    seq_printf(seq, "B: %s=", name);
1105
1106    for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
1107        if (input_bits_to_string(buf, sizeof(buf),
1108                     bitmap[i], skip_empty)) {
1109            skip_empty = false;
1110            seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
1111        }
1112    }
1113
1114    /*
1115     * If no output was produced print a single 0.
1116     */
1117    if (skip_empty)
1118        seq_puts(seq, "0");
1119
1120    seq_putc(seq, '\n');
1121}
1122
1123static int input_devices_seq_show(struct seq_file *seq, void *v)
1124{
1125    struct input_dev *dev = container_of(v, struct input_dev, node);
1126    const char *path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
1127    struct input_handle *handle;
1128
1129    seq_printf(seq, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
1130           dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);
1131
1132    seq_printf(seq, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
1133    seq_printf(seq, "P: Phys=%s\n", dev->phys ? dev->phys : "");
1134    seq_printf(seq, "S: Sysfs=%s\n", path ? path : "");
1135    seq_printf(seq, "U: Uniq=%s\n", dev->uniq ? dev->uniq : "");
1136    seq_printf(seq, "H: Handlers=");
1137
1138    list_for_each_entry(handle, &dev->h_list, d_node)
1139        seq_printf(seq, "%s ", handle->name);
1140    seq_putc(seq, '\n');
1141
1142    input_seq_print_bitmap(seq, "PROP", dev->propbit, INPUT_PROP_MAX);
1143
1144    input_seq_print_bitmap(seq, "EV", dev->evbit, EV_MAX);
1145    if (test_bit(EV_KEY, dev->evbit))
1146        input_seq_print_bitmap(seq, "KEY", dev->keybit, KEY_MAX);
1147    if (test_bit(EV_REL, dev->evbit))
1148        input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
1149    if (test_bit(EV_ABS, dev->evbit))
1150        input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
1151    if (test_bit(EV_MSC, dev->evbit))
1152        input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
1153    if (test_bit(EV_LED, dev->evbit))
1154        input_seq_print_bitmap(seq, "LED", dev->ledbit, LED_MAX);
1155    if (test_bit(EV_SND, dev->evbit))
1156        input_seq_print_bitmap(seq, "SND", dev->sndbit, SND_MAX);
1157    if (test_bit(EV_FF, dev->evbit))
1158        input_seq_print_bitmap(seq, "FF", dev->ffbit, FF_MAX);
1159    if (test_bit(EV_SW, dev->evbit))
1160        input_seq_print_bitmap(seq, "SW", dev->swbit, SW_MAX);
1161
1162    seq_putc(seq, '\n');
1163
1164    kfree(path);
1165    return 0;
1166}
1167
1168static const struct seq_operations input_devices_seq_ops = {
1169    .start = input_devices_seq_start,
1170    .next = input_devices_seq_next,
1171    .stop = input_seq_stop,
1172    .show = input_devices_seq_show,
1173};
1174
1175static int input_proc_devices_open(struct inode *inode, struct file *file)
1176{
1177    return seq_open(file, &input_devices_seq_ops);
1178}
1179
1180static const struct file_operations input_devices_fileops = {
1181    .owner = THIS_MODULE,
1182    .open = input_proc_devices_open,
1183    .poll = input_proc_devices_poll,
1184    .read = seq_read,
1185    .llseek = seq_lseek,
1186    .release = seq_release,
1187};
1188
1189static void *input_handlers_seq_start(struct seq_file *seq, loff_t *pos)
1190{
1191    union input_seq_state *state = (union input_seq_state *)&seq->private;
1192    int error;
1193
1194    /* We need to fit into seq->private pointer */
1195    BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
1196
1197    error = mutex_lock_interruptible(&input_mutex);
1198    if (error) {
1199        state->mutex_acquired = false;
1200        return ERR_PTR(error);
1201    }
1202
1203    state->mutex_acquired = true;
1204    state->pos = *pos;
1205
1206    return seq_list_start(&input_handler_list, *pos);
1207}
1208
1209static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1210{
1211    union input_seq_state *state = (union input_seq_state *)&seq->private;
1212
1213    state->pos = *pos + 1;
1214    return seq_list_next(v, &input_handler_list, pos);
1215}
1216
1217static int input_handlers_seq_show(struct seq_file *seq, void *v)
1218{
1219    struct input_handler *handler = container_of(v, struct input_handler, node);
1220    union input_seq_state *state = (union input_seq_state *)&seq->private;
1221
1222    seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
1223    if (handler->filter)
1224        seq_puts(seq, " (filter)");
1225    if (handler->legacy_minors)
1226        seq_printf(seq, " Minor=%d", handler->minor);
1227    seq_putc(seq, '\n');
1228
1229    return 0;
1230}
1231
1232static const struct seq_operations input_handlers_seq_ops = {
1233    .start = input_handlers_seq_start,
1234    .next = input_handlers_seq_next,
1235    .stop = input_seq_stop,
1236    .show = input_handlers_seq_show,
1237};
1238
1239static int input_proc_handlers_open(struct inode *inode, struct file *file)
1240{
1241    return seq_open(file, &input_handlers_seq_ops);
1242}
1243
1244static const struct file_operations input_handlers_fileops = {
1245    .owner = THIS_MODULE,
1246    .open = input_proc_handlers_open,
1247    .read = seq_read,
1248    .llseek = seq_lseek,
1249    .release = seq_release,
1250};
1251
1252static int __init input_proc_init(void)
1253{
1254    struct proc_dir_entry *entry;
1255
1256    proc_bus_input_dir = proc_mkdir("bus/input", NULL);
1257    if (!proc_bus_input_dir)
1258        return -ENOMEM;
1259
1260    entry = proc_create("devices", 0, proc_bus_input_dir,
1261                &input_devices_fileops);
1262    if (!entry)
1263        goto fail1;
1264
1265    entry = proc_create("handlers", 0, proc_bus_input_dir,
1266                &input_handlers_fileops);
1267    if (!entry)
1268        goto fail2;
1269
1270    return 0;
1271
1272 fail2: remove_proc_entry("devices", proc_bus_input_dir);
1273 fail1: remove_proc_entry("bus/input", NULL);
1274    return -ENOMEM;
1275}
1276
1277static void input_proc_exit(void)
1278{
1279    remove_proc_entry("devices", proc_bus_input_dir);
1280    remove_proc_entry("handlers", proc_bus_input_dir);
1281    remove_proc_entry("bus/input", NULL);
1282}
1283
1284#else /* !CONFIG_PROC_FS */
1285static inline void input_wakeup_procfs_readers(void) { }
1286static inline int input_proc_init(void) { return 0; }
1287static inline void input_proc_exit(void) { }
1288#endif
1289
1290#define INPUT_DEV_STRING_ATTR_SHOW(name) \
1291static ssize_t input_dev_show_##name(struct device *dev, \
1292                     struct device_attribute *attr, \
1293                     char *buf) \
1294{ \
1295    struct input_dev *input_dev = to_input_dev(dev); \
1296                                    \
1297    return scnprintf(buf, PAGE_SIZE, "%s\n", \
1298             input_dev->name ? input_dev->name : ""); \
1299} \
1300static DEVICE_ATTR(name, S_IRUGO, input_dev_show_##name, NULL)
1301
1302INPUT_DEV_STRING_ATTR_SHOW(name);
1303INPUT_DEV_STRING_ATTR_SHOW(phys);
1304INPUT_DEV_STRING_ATTR_SHOW(uniq);
1305
1306static int input_print_modalias_bits(char *buf, int size,
1307                     char name, unsigned long *bm,
1308                     unsigned int min_bit, unsigned int max_bit)
1309{
1310    int len = 0, i;
1311
1312    len += snprintf(buf, max(size, 0), "%c", name);
1313    for (i = min_bit; i < max_bit; i++)
1314        if (bm[BIT_WORD(i)] & BIT_MASK(i))
1315            len += snprintf(buf + len, max(size - len, 0), "%X,", i);
1316    return len;
1317}
1318
1319static int input_print_modalias(char *buf, int size, struct input_dev *id,
1320                int add_cr)
1321{
1322    int len;
1323
1324    len = snprintf(buf, max(size, 0),
1325               "input:b%04Xv%04Xp%04Xe%04X-",
1326               id->id.bustype, id->id.vendor,
1327               id->id.product, id->id.version);
1328
1329    len += input_print_modalias_bits(buf + len, size - len,
1330                'e', id->evbit, 0, EV_MAX);
1331    len += input_print_modalias_bits(buf + len, size - len,
1332                'k', id->keybit, KEY_MIN_INTERESTING, KEY_MAX);
1333    len += input_print_modalias_bits(buf + len, size - len,
1334                'r', id->relbit, 0, REL_MAX);
1335    len += input_print_modalias_bits(buf + len, size - len,
1336                'a', id->absbit, 0, ABS_MAX);
1337    len += input_print_modalias_bits(buf + len, size - len,
1338                'm', id->mscbit, 0, MSC_MAX);
1339    len += input_print_modalias_bits(buf + len, size - len,
1340                'l', id->ledbit, 0, LED_MAX);
1341    len += input_print_modalias_bits(buf + len, size - len,
1342                's', id->sndbit, 0, SND_MAX);
1343    len += input_print_modalias_bits(buf + len, size - len,
1344                'f', id->ffbit, 0, FF_MAX);
1345    len += input_print_modalias_bits(buf + len, size - len,
1346                'w', id->swbit, 0, SW_MAX);
1347
1348    if (add_cr)
1349        len += snprintf(buf + len, max(size - len, 0), "\n");
1350
1351    return len;
1352}
1353
1354static ssize_t input_dev_show_modalias(struct device *dev,
1355                       struct device_attribute *attr,
1356                       char *buf)
1357{
1358    struct input_dev *id = to_input_dev(dev);
1359    ssize_t len;
1360
1361    len = input_print_modalias(buf, PAGE_SIZE, id, 1);
1362
1363    return min_t(int, len, PAGE_SIZE);
1364}
1365static DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
1366
1367static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
1368                  int max, int add_cr);
1369
1370static ssize_t input_dev_show_properties(struct device *dev,
1371                     struct device_attribute *attr,
1372                     char *buf)
1373{
1374    struct input_dev *input_dev = to_input_dev(dev);
1375    int len = input_print_bitmap(buf, PAGE_SIZE, input_dev->propbit,
1376                     INPUT_PROP_MAX, true);
1377    return min_t(int, len, PAGE_SIZE);
1378}
1379static DEVICE_ATTR(properties, S_IRUGO, input_dev_show_properties, NULL);
1380
1381static struct attribute *input_dev_attrs[] = {
1382    &dev_attr_name.attr,
1383    &dev_attr_phys.attr,
1384    &dev_attr_uniq.attr,
1385    &dev_attr_modalias.attr,
1386    &dev_attr_properties.attr,
1387    NULL
1388};
1389
1390static struct attribute_group input_dev_attr_group = {
1391    .attrs = input_dev_attrs,
1392};
1393
1394#define INPUT_DEV_ID_ATTR(name) \
1395static ssize_t input_dev_show_id_##name(struct device *dev, \
1396                    struct device_attribute *attr, \
1397                    char *buf) \
1398{ \
1399    struct input_dev *input_dev = to_input_dev(dev); \
1400    return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name); \
1401} \
1402static DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL)
1403
1404INPUT_DEV_ID_ATTR(bustype);
1405INPUT_DEV_ID_ATTR(vendor);
1406INPUT_DEV_ID_ATTR(product);
1407INPUT_DEV_ID_ATTR(version);
1408
1409static struct attribute *input_dev_id_attrs[] = {
1410    &dev_attr_bustype.attr,
1411    &dev_attr_vendor.attr,
1412    &dev_attr_product.attr,
1413    &dev_attr_version.attr,
1414    NULL
1415};
1416
1417static struct attribute_group input_dev_id_attr_group = {
1418    .name = "id",
1419    .attrs = input_dev_id_attrs,
1420};
1421
1422static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
1423                  int max, int add_cr)
1424{
1425    int i;
1426    int len = 0;
1427    bool skip_empty = true;
1428
1429    for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
1430        len += input_bits_to_string(buf + len, max(buf_size - len, 0),
1431                        bitmap[i], skip_empty);
1432        if (len) {
1433            skip_empty = false;
1434            if (i > 0)
1435                len += snprintf(buf + len, max(buf_size - len, 0), " ");
1436        }
1437    }
1438
1439    /*
1440     * If no output was produced print a single 0.
1441     */
1442    if (len == 0)
1443        len = snprintf(buf, buf_size, "%d", 0);
1444
1445    if (add_cr)
1446        len += snprintf(buf + len, max(buf_size - len, 0), "\n");
1447
1448    return len;
1449}
1450
1451#define INPUT_DEV_CAP_ATTR(ev, bm) \
1452static ssize_t input_dev_show_cap_##bm(struct device *dev, \
1453                       struct device_attribute *attr, \
1454                       char *buf) \
1455{ \
1456    struct input_dev *input_dev = to_input_dev(dev); \
1457    int len = input_print_bitmap(buf, PAGE_SIZE, \
1458                     input_dev->bm##bit, ev##_MAX, \
1459                     true); \
1460    return min_t(int, len, PAGE_SIZE); \
1461} \
1462static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
1463
1464INPUT_DEV_CAP_ATTR(EV, ev);
1465INPUT_DEV_CAP_ATTR(KEY, key);
1466INPUT_DEV_CAP_ATTR(REL, rel);
1467INPUT_DEV_CAP_ATTR(ABS, abs);
1468INPUT_DEV_CAP_ATTR(MSC, msc);
1469INPUT_DEV_CAP_ATTR(LED, led);
1470INPUT_DEV_CAP_ATTR(SND, snd);
1471INPUT_DEV_CAP_ATTR(FF, ff);
1472INPUT_DEV_CAP_ATTR(SW, sw);
1473
1474static struct attribute *input_dev_caps_attrs[] = {
1475    &dev_attr_ev.attr,
1476    &dev_attr_key.attr,
1477    &dev_attr_rel.attr,
1478    &dev_attr_abs.attr,
1479    &dev_attr_msc.attr,
1480    &dev_attr_led.attr,
1481    &dev_attr_snd.attr,
1482    &dev_attr_ff.attr,
1483    &dev_attr_sw.attr,
1484    NULL
1485};
1486
1487static struct attribute_group input_dev_caps_attr_group = {
1488    .name = "capabilities",
1489    .attrs = input_dev_caps_attrs,
1490};
1491
1492static const struct attribute_group *input_dev_attr_groups[] = {
1493    &input_dev_attr_group,
1494    &input_dev_id_attr_group,
1495    &input_dev_caps_attr_group,
1496    NULL
1497};
1498
1499static void input_dev_release(struct device *device)
1500{
1501    struct input_dev *dev = to_input_dev(device);
1502
1503    input_ff_destroy(dev);
1504    input_mt_destroy_slots(dev);
1505    kfree(dev->absinfo);
1506    kfree(dev->vals);
1507    kfree(dev);
1508
1509    module_put(THIS_MODULE);
1510}
1511
1512/*
1513 * Input uevent interface - loading event handlers based on
1514 * device bitfields.
1515 */
1516static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
1517                   const char *name, unsigned long *bitmap, int max)
1518{
1519    int len;
1520
1521    if (add_uevent_var(env, "%s", name))
1522        return -ENOMEM;
1523
1524    len = input_print_bitmap(&env->buf[env->buflen - 1],
1525                 sizeof(env->buf) - env->buflen,
1526                 bitmap, max, false);
1527    if (len >= (sizeof(env->buf) - env->buflen))
1528        return -ENOMEM;
1529
1530    env->buflen += len;
1531    return 0;
1532}
1533
1534static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
1535                     struct input_dev *dev)
1536{
1537    int len;
1538
1539    if (add_uevent_var(env, "MODALIAS="))
1540        return -ENOMEM;
1541
1542    len = input_print_modalias(&env->buf[env->buflen - 1],
1543                   sizeof(env->buf) - env->buflen,
1544                   dev, 0);
1545    if (len >= (sizeof(env->buf) - env->buflen))
1546        return -ENOMEM;
1547
1548    env->buflen += len;
1549    return 0;
1550}
1551
1552#define INPUT_ADD_HOTPLUG_VAR(fmt, val...) \
1553    do { \
1554        int err = add_uevent_var(env, fmt, val); \
1555        if (err) \
1556            return err; \
1557    } while (0)
1558
1559#define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max) \
1560    do { \
1561        int err = input_add_uevent_bm_var(env, name, bm, max); \
1562        if (err) \
1563            return err; \
1564    } while (0)
1565
1566#define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev) \
1567    do { \
1568        int err = input_add_uevent_modalias_var(env, dev); \
1569        if (err) \
1570            return err; \
1571    } while (0)
1572
1573static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
1574{
1575    struct input_dev *dev = to_input_dev(device);
1576
1577    INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
1578                dev->id.bustype, dev->id.vendor,
1579                dev->id.product, dev->id.version);
1580    if (dev->name)
1581        INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
1582    if (dev->phys)
1583        INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
1584    if (dev->uniq)
1585        INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);
1586
1587    INPUT_ADD_HOTPLUG_BM_VAR("PROP=", dev->propbit, INPUT_PROP_MAX);
1588
1589    INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
1590    if (test_bit(EV_KEY, dev->evbit))
1591        INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
1592    if (test_bit(EV_REL, dev->evbit))
1593        INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
1594    if (test_bit(EV_ABS, dev->evbit))
1595        INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
1596    if (test_bit(EV_MSC, dev->evbit))
1597        INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
1598    if (test_bit(EV_LED, dev->evbit))
1599        INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
1600    if (test_bit(EV_SND, dev->evbit))
1601        INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
1602    if (test_bit(EV_FF, dev->evbit))
1603        INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
1604    if (test_bit(EV_SW, dev->evbit))
1605        INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
1606
1607    INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
1608
1609    return 0;
1610}
1611
1612#define INPUT_DO_TOGGLE(dev, type, bits, on) \
1613    do { \
1614        int i; \
1615        bool active; \
1616                                    \
1617        if (!test_bit(EV_##type, dev->evbit)) \
1618            break; \
1619                                    \
1620        for (i = 0; i < type##_MAX; i++) { \
1621            if (!test_bit(i, dev->bits##bit)) \
1622                continue; \
1623                                    \
1624            active = test_bit(i, dev->bits); \
1625            if (!active && !on) \
1626                continue; \
1627                                    \
1628            dev->event(dev, EV_##type, i, on ? active : 0); \
1629        } \
1630    } while (0)
1631
1632static void input_dev_toggle(struct input_dev *dev, bool activate)
1633{
1634    if (!dev->event)
1635        return;
1636
1637    INPUT_DO_TOGGLE(dev, LED, led, activate);
1638    INPUT_DO_TOGGLE(dev, SND, snd, activate);
1639
1640    if (activate && test_bit(EV_REP, dev->evbit)) {
1641        dev->event(dev, EV_REP, REP_PERIOD, dev->rep[REP_PERIOD]);
1642        dev->event(dev, EV_REP, REP_DELAY, dev->rep[REP_DELAY]);
1643    }
1644}
1645
1646/**
1647 * input_reset_device() - reset/restore the state of input device
1648 * @dev: input device whose state needs to be reset
1649 *
1650 * This function tries to reset the state of an opened input device and
1651 * bring internal state and state if the hardware in sync with each other.
1652 * We mark all keys as released, restore LED state, repeat rate, etc.
1653 */
1654void input_reset_device(struct input_dev *dev)
1655{
1656    mutex_lock(&dev->mutex);
1657
1658    if (dev->users) {
1659        input_dev_toggle(dev, true);
1660
1661        /*
1662         * Keys that have been pressed at suspend time are unlikely
1663         * to be still pressed when we resume.
1664         */
1665        spin_lock_irq(&dev->event_lock);
1666        input_dev_release_keys(dev);
1667        spin_unlock_irq(&dev->event_lock);
1668    }
1669
1670    mutex_unlock(&dev->mutex);
1671}
1672EXPORT_SYMBOL(input_reset_device);
1673
1674#ifdef CONFIG_PM
1675static int input_dev_suspend(struct device *dev)
1676{
1677    struct input_dev *input_dev = to_input_dev(dev);
1678
1679    mutex_lock(&input_dev->mutex);
1680
1681    if (input_dev->users)
1682        input_dev_toggle(input_dev, false);
1683
1684    mutex_unlock(&input_dev->mutex);
1685
1686    return 0;
1687}
1688
1689static int input_dev_resume(struct device *dev)
1690{
1691    struct input_dev *input_dev = to_input_dev(dev);
1692
1693    input_reset_device(input_dev);
1694
1695    return 0;
1696}
1697
1698static const struct dev_pm_ops input_dev_pm_ops = {
1699    .suspend = input_dev_suspend,
1700    .resume = input_dev_resume,
1701    .poweroff = input_dev_suspend,
1702    .restore = input_dev_resume,
1703};
1704#endif /* CONFIG_PM */
1705
1706static struct device_type input_dev_type = {
1707    .groups = input_dev_attr_groups,
1708    .release = input_dev_release,
1709    .uevent = input_dev_uevent,
1710#ifdef CONFIG_PM
1711    .pm = &input_dev_pm_ops,
1712#endif
1713};
1714
1715static char *input_devnode(struct device *dev, umode_t *mode)
1716{
1717    return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
1718}
1719
1720struct class input_class = {
1721    .name = "input",
1722    .devnode = input_devnode,
1723};
1724EXPORT_SYMBOL_GPL(input_class);
1725
1726/**
1727 * input_allocate_device - allocate memory for new input device
1728 *
1729 * Returns prepared struct input_dev or %NULL.
1730 *
1731 * NOTE: Use input_free_device() to free devices that have not been
1732 * registered; input_unregister_device() should be used for already
1733 * registered devices.
1734 */
1735struct input_dev *input_allocate_device(void)
1736{
1737    struct input_dev *dev;
1738
1739    dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);
1740    if (dev) {
1741        dev->dev.type = &input_dev_type;
1742        dev->dev.class = &input_class;
1743        device_initialize(&dev->dev);
1744        mutex_init(&dev->mutex);
1745        spin_lock_init(&dev->event_lock);
1746        INIT_LIST_HEAD(&dev->h_list);
1747        INIT_LIST_HEAD(&dev->node);
1748
1749        __module_get(THIS_MODULE);
1750    }
1751
1752    return dev;
1753}
1754EXPORT_SYMBOL(input_allocate_device);
1755
1756struct input_devres {
1757    struct input_dev *input;
1758};
1759
1760static int devm_input_device_match(struct device *dev, void *res, void *data)
1761{
1762    struct input_devres *devres = res;
1763
1764    return devres->input == data;
1765}
1766
1767static void devm_input_device_release(struct device *dev, void *res)
1768{
1769    struct input_devres *devres = res;
1770    struct input_dev *input = devres->input;
1771
1772    dev_dbg(dev, "%s: dropping reference to %s\n",
1773        __func__, dev_name(&input->dev));
1774    input_put_device(input);
1775}
1776
1777/**
1778 * devm_input_allocate_device - allocate managed input device
1779 * @dev: device owning the input device being created
1780 *
1781 * Returns prepared struct input_dev or %NULL.
1782 *
1783 * Managed input devices do not need to be explicitly unregistered or
1784 * freed as it will be done automatically when owner device unbinds from
1785 * its driver (or binding fails). Once managed input device is allocated,
1786 * it is ready to be set up and registered in the same fashion as regular
1787 * input device. There are no special devm_input_device_[un]register()
1788 * variants, regular ones work with both managed and unmanaged devices,
1789 * should you need them. In most cases however, managed input device need
1790 * not be explicitly unregistered or freed.
1791 *
1792 * NOTE: the owner device is set up as parent of input device and users
1793 * should not override it.
1794 */
1795struct input_dev *devm_input_allocate_device(struct device *dev)
1796{
1797    struct input_dev *input;
1798    struct input_devres *devres;
1799
1800    devres = devres_alloc(devm_input_device_release,
1801                  sizeof(struct input_devres), GFP_KERNEL);
1802    if (!devres)
1803        return NULL;
1804
1805    input = input_allocate_device();
1806    if (!input) {
1807        devres_free(devres);
1808        return NULL;
1809    }
1810
1811    input->dev.parent = dev;
1812    input->devres_managed = true;
1813
1814    devres->input = input;
1815    devres_add(dev, devres);
1816
1817    return input;
1818}
1819EXPORT_SYMBOL(devm_input_allocate_device);
1820
1821/**
1822 * input_free_device - free memory occupied by input_dev structure
1823 * @dev: input device to free
1824 *
1825 * This function should only be used if input_register_device()
1826 * was not called yet or if it failed. Once device was registered
1827 * use input_unregister_device() and memory will be freed once last
1828 * reference to the device is dropped.
1829 *
1830 * Device should be allocated by input_allocate_device().
1831 *
1832 * NOTE: If there are references to the input device then memory
1833 * will not be freed until last reference is dropped.
1834 */
1835void input_free_device(struct input_dev *dev)
1836{
1837    if (dev) {
1838        if (dev->devres_managed)
1839            WARN_ON(devres_destroy(dev->dev.parent,
1840                        devm_input_device_release,
1841                        devm_input_device_match,
1842                        dev));
1843        input_put_device(dev);
1844    }
1845}
1846EXPORT_SYMBOL(input_free_device);
1847
1848/**
1849 * input_set_capability - mark device as capable of a certain event
1850 * @dev: device that is capable of emitting or accepting event
1851 * @type: type of the event (EV_KEY, EV_REL, etc...)
1852 * @code: event code
1853 *
1854 * In addition to setting up corresponding bit in appropriate capability
1855 * bitmap the function also adjusts dev->evbit.
1856 */
1857void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
1858{
1859    switch (type) {
1860    case EV_KEY:
1861        __set_bit(code, dev->keybit);
1862        break;
1863
1864    case EV_REL:
1865        __set_bit(code, dev->relbit);
1866        break;
1867
1868    case EV_ABS:
1869        __set_bit(code, dev->absbit);
1870        break;
1871
1872    case EV_MSC:
1873        __set_bit(code, dev->mscbit);
1874        break;
1875
1876    case EV_SW:
1877        __set_bit(code, dev->swbit);
1878        break;
1879
1880    case EV_LED:
1881        __set_bit(code, dev->ledbit);
1882        break;
1883
1884    case EV_SND:
1885        __set_bit(code, dev->sndbit);
1886        break;
1887
1888    case EV_FF:
1889        __set_bit(code, dev->ffbit);
1890        break;
1891
1892    case EV_PWR:
1893        /* do nothing */
1894        break;
1895
1896    default:
1897        pr_err("input_set_capability: unknown type %u (code %u)\n",
1898               type, code);
1899        dump_stack();
1900        return;
1901    }
1902
1903    __set_bit(type, dev->evbit);
1904}
1905EXPORT_SYMBOL(input_set_capability);
1906
1907static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
1908{
1909    int mt_slots;
1910    int i;
1911    unsigned int events;
1912
1913    if (dev->mt) {
1914        mt_slots = dev->mt->num_slots;
1915    } else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
1916        mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
1917               dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,
1918        mt_slots = clamp(mt_slots, 2, 32);
1919    } else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
1920        mt_slots = 2;
1921    } else {
1922        mt_slots = 0;
1923    }
1924
1925    events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
1926
1927    for (i = 0; i < ABS_CNT; i++) {
1928        if (test_bit(i, dev->absbit)) {
1929            if (input_is_mt_axis(i))
1930                events += mt_slots;
1931            else
1932                events++;
1933        }
1934    }
1935
1936    for (i = 0; i < REL_CNT; i++)
1937        if (test_bit(i, dev->relbit))
1938            events++;
1939
1940    /* Make room for KEY and MSC events */
1941    events += 7;
1942
1943    return events;
1944}
1945
1946#define INPUT_CLEANSE_BITMASK(dev, type, bits) \
1947    do { \
1948        if (!test_bit(EV_##type, dev->evbit)) \
1949            memset(dev->bits##bit, 0, \
1950                sizeof(dev->bits##bit)); \
1951    } while (0)
1952
1953static void input_cleanse_bitmasks(struct input_dev *dev)
1954{
1955    INPUT_CLEANSE_BITMASK(dev, KEY, key);
1956    INPUT_CLEANSE_BITMASK(dev, REL, rel);
1957    INPUT_CLEANSE_BITMASK(dev, ABS, abs);
1958    INPUT_CLEANSE_BITMASK(dev, MSC, msc);
1959    INPUT_CLEANSE_BITMASK(dev, LED, led);
1960    INPUT_CLEANSE_BITMASK(dev, SND, snd);
1961    INPUT_CLEANSE_BITMASK(dev, FF, ff);
1962    INPUT_CLEANSE_BITMASK(dev, SW, sw);
1963}
1964
1965static void __input_unregister_device(struct input_dev *dev)
1966{
1967    struct input_handle *handle, *next;
1968
1969    input_disconnect_device(dev);
1970
1971    mutex_lock(&input_mutex);
1972
1973    list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
1974        handle->handler->disconnect(handle);
1975    WARN_ON(!list_empty(&dev->h_list));
1976
1977    del_timer_sync(&dev->timer);
1978    list_del_init(&dev->node);
1979
1980    input_wakeup_procfs_readers();
1981
1982    mutex_unlock(&input_mutex);
1983
1984    device_del(&dev->dev);
1985}
1986
1987static void devm_input_device_unregister(struct device *dev, void *res)
1988{
1989    struct input_devres *devres = res;
1990    struct input_dev *input = devres->input;
1991
1992    dev_dbg(dev, "%s: unregistering device %s\n",
1993        __func__, dev_name(&input->dev));
1994    __input_unregister_device(input);
1995}
1996
1997/**
1998 * input_register_device - register device with input core
1999 * @dev: device to be registered
2000 *
2001 * This function registers device with input core. The device must be
2002 * allocated with input_allocate_device() and all it's capabilities
2003 * set up before registering.
2004 * If function fails the device must be freed with input_free_device().
2005 * Once device has been successfully registered it can be unregistered
2006 * with input_unregister_device(); input_free_device() should not be
2007 * called in this case.
2008 *
2009 * Note that this function is also used to register managed input devices
2010 * (ones allocated with devm_input_allocate_device()). Such managed input
2011 * devices need not be explicitly unregistered or freed, their tear down
2012 * is controlled by the devres infrastructure. It is also worth noting
2013 * that tear down of managed input devices is internally a 2-step process:
2014 * registered managed input device is first unregistered, but stays in
2015 * memory and can still handle input_event() calls (although events will
2016 * not be delivered anywhere). The freeing of managed input device will
2017 * happen later, when devres stack is unwound to the point where device
2018 * allocation was made.
2019 */
2020int input_register_device(struct input_dev *dev)
2021{
2022    static atomic_t input_no = ATOMIC_INIT(0);
2023    struct input_devres *devres = NULL;
2024    struct input_handler *handler;
2025    unsigned int packet_size;
2026    const char *path;
2027    int error;
2028
2029    if (dev->devres_managed) {
2030        devres = devres_alloc(devm_input_device_unregister,
2031                      sizeof(struct input_devres), GFP_KERNEL);
2032        if (!devres)
2033            return -ENOMEM;
2034
2035        devres->input = dev;
2036    }
2037
2038    /* Every input device generates EV_SYN/SYN_REPORT events. */
2039    __set_bit(EV_SYN, dev->evbit);
2040
2041    /* KEY_RESERVED is not supposed to be transmitted to userspace. */
2042    __clear_bit(KEY_RESERVED, dev->keybit);
2043
2044    /* Make sure that bitmasks not mentioned in dev->evbit are clean. */
2045    input_cleanse_bitmasks(dev);
2046
2047    packet_size = input_estimate_events_per_packet(dev);
2048    if (dev->hint_events_per_packet < packet_size)
2049        dev->hint_events_per_packet = packet_size;
2050
2051    dev->max_vals = max(dev->hint_events_per_packet, packet_size) + 2;
2052    dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
2053    if (!dev->vals) {
2054        error = -ENOMEM;
2055        goto err_devres_free;
2056    }
2057
2058    /*
2059     * If delay and period are pre-set by the driver, then autorepeating
2060     * is handled by the driver itself and we don't do it in input.c.
2061     */
2062    init_timer(&dev->timer);
2063    if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
2064        dev->timer.data = (long) dev;
2065        dev->timer.function = input_repeat_key;
2066        dev->rep[REP_DELAY] = 250;
2067        dev->rep[REP_PERIOD] = 33;
2068    }
2069
2070    if (!dev->getkeycode)
2071        dev->getkeycode = input_default_getkeycode;
2072
2073    if (!dev->setkeycode)
2074        dev->setkeycode = input_default_setkeycode;
2075
2076    dev_set_name(&dev->dev, "input%ld",
2077             (unsigned long) atomic_inc_return(&input_no) - 1);
2078
2079    error = device_add(&dev->dev);
2080    if (error)
2081        goto err_free_vals;
2082
2083    path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
2084    pr_info("%s as %s\n",
2085        dev->name ? dev->name : "Unspecified device",
2086        path ? path : "N/A");
2087    kfree(path);
2088
2089    error = mutex_lock_interruptible(&input_mutex);
2090    if (error)
2091        goto err_device_del;
2092
2093    list_add_tail(&dev->node, &input_dev_list);
2094
2095    list_for_each_entry(handler, &input_handler_list, node)
2096        input_attach_handler(dev, handler);
2097
2098    input_wakeup_procfs_readers();
2099
2100    mutex_unlock(&input_mutex);
2101
2102    if (dev->devres_managed) {
2103        dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
2104            __func__, dev_name(&dev->dev));
2105        devres_add(dev->dev.parent, devres);
2106    }
2107    return 0;
2108
2109err_device_del:
2110    device_del(&dev->dev);
2111err_free_vals:
2112    kfree(dev->vals);
2113    dev->vals = NULL;
2114err_devres_free:
2115    devres_free(devres);
2116    return error;
2117}
2118EXPORT_SYMBOL(input_register_device);
2119
2120/**
2121 * input_unregister_device - unregister previously registered device
2122 * @dev: device to be unregistered
2123 *
2124 * This function unregisters an input device. Once device is unregistered
2125 * the caller should not try to access it as it may get freed at any moment.
2126 */
2127void input_unregister_device(struct input_dev *dev)
2128{
2129    if (dev->devres_managed) {
2130        WARN_ON(devres_destroy(dev->dev.parent,
2131                    devm_input_device_unregister,
2132                    devm_input_device_match,
2133                    dev));
2134        __input_unregister_device(dev);
2135        /*
2136         * We do not do input_put_device() here because it will be done
2137         * when 2nd devres fires up.
2138         */
2139    } else {
2140        __input_unregister_device(dev);
2141        input_put_device(dev);
2142    }
2143}
2144EXPORT_SYMBOL(input_unregister_device);
2145
2146/**
2147 * input_register_handler - register a new input handler
2148 * @handler: handler to be registered
2149 *
2150 * This function registers a new input handler (interface) for input
2151 * devices in the system and attaches it to all input devices that
2152 * are compatible with the handler.
2153 */
2154int input_register_handler(struct input_handler *handler)
2155{
2156    struct input_dev *dev;
2157    int error;
2158
2159    error = mutex_lock_interruptible(&input_mutex);
2160    if (error)
2161        return error;
2162
2163    INIT_LIST_HEAD(&handler->h_list);
2164
2165    list_add_tail(&handler->node, &input_handler_list);
2166
2167    list_for_each_entry(dev, &input_dev_list, node)
2168        input_attach_handler(dev, handler);
2169
2170    input_wakeup_procfs_readers();
2171
2172    mutex_unlock(&input_mutex);
2173    return 0;
2174}
2175EXPORT_SYMBOL(input_register_handler);
2176
2177/**
2178 * input_unregister_handler - unregisters an input handler
2179 * @handler: handler to be unregistered
2180 *
2181 * This function disconnects a handler from its input devices and
2182 * removes it from lists of known handlers.
2183 */
2184void input_unregister_handler(struct input_handler *handler)
2185{
2186    struct input_handle *handle, *next;
2187
2188    mutex_lock(&input_mutex);
2189
2190    list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
2191        handler->disconnect(handle);
2192    WARN_ON(!list_empty(&handler->h_list));
2193
2194    list_del_init(&handler->node);
2195
2196    input_wakeup_procfs_readers();
2197
2198    mutex_unlock(&input_mutex);
2199}
2200EXPORT_SYMBOL(input_unregister_handler);
2201
2202/**
2203 * input_handler_for_each_handle - handle iterator
2204 * @handler: input handler to iterate
2205 * @data: data for the callback
2206 * @fn: function to be called for each handle
2207 *
2208 * Iterate over @bus's list of devices, and call @fn for each, passing
2209 * it @data and stop when @fn returns a non-zero value. The function is
2210 * using RCU to traverse the list and therefore may be usind in atonic
2211 * contexts. The @fn callback is invoked from RCU critical section and
2212 * thus must not sleep.
2213 */
2214int input_handler_for_each_handle(struct input_handler *handler, void *data,
2215                  int (*fn)(struct input_handle *, void *))
2216{
2217    struct input_handle *handle;
2218    int retval = 0;
2219
2220    rcu_read_lock();
2221
2222    list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
2223        retval = fn(handle, data);
2224        if (retval)
2225            break;
2226    }
2227
2228    rcu_read_unlock();
2229
2230    return retval;
2231}
2232EXPORT_SYMBOL(input_handler_for_each_handle);
2233
2234/**
2235 * input_register_handle - register a new input handle
2236 * @handle: handle to register
2237 *
2238 * This function puts a new input handle onto device's
2239 * and handler's lists so that events can flow through
2240 * it once it is opened using input_open_device().
2241 *
2242 * This function is supposed to be called from handler's
2243 * connect() method.
2244 */
2245int input_register_handle(struct input_handle *handle)
2246{
2247    struct input_handler *handler = handle->handler;
2248    struct input_dev *dev = handle->dev;
2249    int error;
2250
2251    /*
2252     * We take dev->mutex here to prevent race with
2253     * input_release_device().
2254     */
2255    error = mutex_lock_interruptible(&dev->mutex);
2256    if (error)
2257        return error;
2258
2259    /*
2260     * Filters go to the head of the list, normal handlers
2261     * to the tail.
2262     */
2263    if (handler->filter)
2264        list_add_rcu(&handle->d_node, &dev->h_list);
2265    else
2266        list_add_tail_rcu(&handle->d_node, &dev->h_list);
2267
2268    mutex_unlock(&dev->mutex);
2269
2270    /*
2271     * Since we are supposed to be called from ->connect()
2272     * which is mutually exclusive with ->disconnect()
2273     * we can't be racing with input_unregister_handle()
2274     * and so separate lock is not needed here.
2275     */
2276    list_add_tail_rcu(&handle->h_node, &handler->h_list);
2277
2278    if (handler->start)
2279        handler->start(handle);
2280
2281    return 0;
2282}
2283EXPORT_SYMBOL(input_register_handle);
2284
2285/**
2286 * input_unregister_handle - unregister an input handle
2287 * @handle: handle to unregister
2288 *
2289 * This function removes input handle from device's
2290 * and handler's lists.
2291 *
2292 * This function is supposed to be called from handler's
2293 * disconnect() method.
2294 */
2295void input_unregister_handle(struct input_handle *handle)
2296{
2297    struct input_dev *dev = handle->dev;
2298
2299    list_del_rcu(&handle->h_node);
2300
2301    /*
2302     * Take dev->mutex to prevent race with input_release_device().
2303     */
2304    mutex_lock(&dev->mutex);
2305    list_del_rcu(&handle->d_node);
2306    mutex_unlock(&dev->mutex);
2307
2308    synchronize_rcu();
2309}
2310EXPORT_SYMBOL(input_unregister_handle);
2311
2312/**
2313 * input_get_new_minor - allocates a new input minor number
2314 * @legacy_base: beginning or the legacy range to be searched
2315 * @legacy_num: size of legacy range
2316 * @allow_dynamic: whether we can also take ID from the dynamic range
2317 *
2318 * This function allocates a new device minor for from input major namespace.
2319 * Caller can request legacy minor by specifying @legacy_base and @legacy_num
2320 * parameters and whether ID can be allocated from dynamic range if there are
2321 * no free IDs in legacy range.
2322 */
2323int input_get_new_minor(int legacy_base, unsigned int legacy_num,
2324            bool allow_dynamic)
2325{
2326    /*
2327     * This function should be called from input handler's ->connect()
2328     * methods, which are serialized with input_mutex, so no additional
2329     * locking is needed here.
2330     */
2331    if (legacy_base >= 0) {
2332        int minor = ida_simple_get(&input_ida,
2333                       legacy_base,
2334                       legacy_base + legacy_num,
2335                       GFP_KERNEL);
2336        if (minor >= 0 || !allow_dynamic)
2337            return minor;
2338    }
2339
2340    return ida_simple_get(&input_ida,
2341                  INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
2342                  GFP_KERNEL);
2343}
2344EXPORT_SYMBOL(input_get_new_minor);
2345
2346/**
2347 * input_free_minor - release previously allocated minor
2348 * @minor: minor to be released
2349 *
2350 * This function releases previously allocated input minor so that it can be
2351 * reused later.
2352 */
2353void input_free_minor(unsigned int minor)
2354{
2355    ida_simple_remove(&input_ida, minor);
2356}
2357EXPORT_SYMBOL(input_free_minor);
2358
2359static int __init input_init(void)
2360{
2361    int err;
2362
2363    err = class_register(&input_class);
2364    if (err) {
2365        pr_err("unable to register input_dev class\n");
2366        return err;
2367    }
2368
2369    err = input_proc_init();
2370    if (err)
2371        goto fail1;
2372
2373    err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
2374                     INPUT_MAX_CHAR_DEVICES, "input");
2375    if (err) {
2376        pr_err("unable to register char major %d", INPUT_MAJOR);
2377        goto fail2;
2378    }
2379
2380    return 0;
2381
2382 fail2: input_proc_exit();
2383 fail1: class_unregister(&input_class);
2384    return err;
2385}
2386
2387static void __exit input_exit(void)
2388{
2389    input_proc_exit();
2390    unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
2391                 INPUT_MAX_CHAR_DEVICES);
2392    class_unregister(&input_class);
2393}
2394
2395subsys_initcall(input_init);
2396module_exit(input_exit);
2397

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