xref: /openbmc/linux/drivers/input/input.c (revision 68a767dd)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * The input core
4  *
5  * Copyright (c) 1999-2002 Vojtech Pavlik
6  */
7 
8 
9 #define pr_fmt(fmt) KBUILD_BASENAME ": " fmt
10 
11 #include <linux/init.h>
12 #include <linux/types.h>
13 #include <linux/idr.h>
14 #include <linux/input/mt.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/random.h>
18 #include <linux/major.h>
19 #include <linux/proc_fs.h>
20 #include <linux/sched.h>
21 #include <linux/seq_file.h>
22 #include <linux/pm.h>
23 #include <linux/poll.h>
24 #include <linux/device.h>
25 #include <linux/kstrtox.h>
26 #include <linux/mutex.h>
27 #include <linux/rcupdate.h>
28 #include "input-compat.h"
29 #include "input-core-private.h"
30 #include "input-poller.h"
31 
32 MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
33 MODULE_DESCRIPTION("Input core");
34 MODULE_LICENSE("GPL");
35 
36 #define INPUT_MAX_CHAR_DEVICES		1024
37 #define INPUT_FIRST_DYNAMIC_DEV		256
38 static DEFINE_IDA(input_ida);
39 
40 static LIST_HEAD(input_dev_list);
41 static 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  */
49 static DEFINE_MUTEX(input_mutex);
50 
51 static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };
52 
53 static const unsigned int input_max_code[EV_CNT] = {
54 	[EV_KEY] = KEY_MAX,
55 	[EV_REL] = REL_MAX,
56 	[EV_ABS] = ABS_MAX,
57 	[EV_MSC] = MSC_MAX,
58 	[EV_SW] = SW_MAX,
59 	[EV_LED] = LED_MAX,
60 	[EV_SND] = SND_MAX,
61 	[EV_FF] = FF_MAX,
62 };
63 
is_event_supported(unsigned int code,unsigned long * bm,unsigned int max)64 static inline int is_event_supported(unsigned int code,
65 				     unsigned long *bm, unsigned int max)
66 {
67 	return code <= max && test_bit(code, bm);
68 }
69 
input_defuzz_abs_event(int value,int old_val,int fuzz)70 static int input_defuzz_abs_event(int value, int old_val, int fuzz)
71 {
72 	if (fuzz) {
73 		if (value > old_val - fuzz / 2 && value < old_val + fuzz / 2)
74 			return old_val;
75 
76 		if (value > old_val - fuzz && value < old_val + fuzz)
77 			return (old_val * 3 + value) / 4;
78 
79 		if (value > old_val - fuzz * 2 && value < old_val + fuzz * 2)
80 			return (old_val + value) / 2;
81 	}
82 
83 	return value;
84 }
85 
input_start_autorepeat(struct input_dev * dev,int code)86 static void input_start_autorepeat(struct input_dev *dev, int code)
87 {
88 	if (test_bit(EV_REP, dev->evbit) &&
89 	    dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
90 	    dev->timer.function) {
91 		dev->repeat_key = code;
92 		mod_timer(&dev->timer,
93 			  jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
94 	}
95 }
96 
input_stop_autorepeat(struct input_dev * dev)97 static void input_stop_autorepeat(struct input_dev *dev)
98 {
99 	del_timer(&dev->timer);
100 }
101 
102 /*
103  * Pass event first through all filters and then, if event has not been
104  * filtered out, through all open handles. This function is called with
105  * dev->event_lock held and interrupts disabled.
106  */
input_to_handler(struct input_handle * handle,struct input_value * vals,unsigned int count)107 static unsigned int input_to_handler(struct input_handle *handle,
108 			struct input_value *vals, unsigned int count)
109 {
110 	struct input_handler *handler = handle->handler;
111 	struct input_value *end = vals;
112 	struct input_value *v;
113 
114 	if (handler->filter) {
115 		for (v = vals; v != vals + count; v++) {
116 			if (handler->filter(handle, v->type, v->code, v->value))
117 				continue;
118 			if (end != v)
119 				*end = *v;
120 			end++;
121 		}
122 		count = end - vals;
123 	}
124 
125 	if (!count)
126 		return 0;
127 
128 	if (handler->events)
129 		handler->events(handle, vals, count);
130 	else if (handler->event)
131 		for (v = vals; v != vals + count; v++)
132 			handler->event(handle, v->type, v->code, v->value);
133 
134 	return count;
135 }
136 
137 /*
138  * Pass values first through all filters and then, if event has not been
139  * filtered out, through all open handles. This function is called with
140  * dev->event_lock held and interrupts disabled.
141  */
input_pass_values(struct input_dev * dev,struct input_value * vals,unsigned int count)142 static void input_pass_values(struct input_dev *dev,
143 			      struct input_value *vals, unsigned int count)
144 {
145 	struct input_handle *handle;
146 	struct input_value *v;
147 
148 	lockdep_assert_held(&dev->event_lock);
149 
150 	if (!count)
151 		return;
152 
153 	rcu_read_lock();
154 
155 	handle = rcu_dereference(dev->grab);
156 	if (handle) {
157 		count = input_to_handler(handle, vals, count);
158 	} else {
159 		list_for_each_entry_rcu(handle, &dev->h_list, d_node)
160 			if (handle->open) {
161 				count = input_to_handler(handle, vals, count);
162 				if (!count)
163 					break;
164 			}
165 	}
166 
167 	rcu_read_unlock();
168 
169 	/* trigger auto repeat for key events */
170 	if (test_bit(EV_REP, dev->evbit) && test_bit(EV_KEY, dev->evbit)) {
171 		for (v = vals; v != vals + count; v++) {
172 			if (v->type == EV_KEY && v->value != 2) {
173 				if (v->value)
174 					input_start_autorepeat(dev, v->code);
175 				else
176 					input_stop_autorepeat(dev);
177 			}
178 		}
179 	}
180 }
181 
182 #define INPUT_IGNORE_EVENT	0
183 #define INPUT_PASS_TO_HANDLERS	1
184 #define INPUT_PASS_TO_DEVICE	2
185 #define INPUT_SLOT		4
186 #define INPUT_FLUSH		8
187 #define INPUT_PASS_TO_ALL	(INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
188 
input_handle_abs_event(struct input_dev * dev,unsigned int code,int * pval)189 static int input_handle_abs_event(struct input_dev *dev,
190 				  unsigned int code, int *pval)
191 {
192 	struct input_mt *mt = dev->mt;
193 	bool is_new_slot = false;
194 	bool is_mt_event;
195 	int *pold;
196 
197 	if (code == ABS_MT_SLOT) {
198 		/*
199 		 * "Stage" the event; we'll flush it later, when we
200 		 * get actual touch data.
201 		 */
202 		if (mt && *pval >= 0 && *pval < mt->num_slots)
203 			mt->slot = *pval;
204 
205 		return INPUT_IGNORE_EVENT;
206 	}
207 
208 	is_mt_event = input_is_mt_value(code);
209 
210 	if (!is_mt_event) {
211 		pold = &dev->absinfo[code].value;
212 	} else if (mt) {
213 		pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
214 		is_new_slot = mt->slot != dev->absinfo[ABS_MT_SLOT].value;
215 	} else {
216 		/*
217 		 * Bypass filtering for multi-touch events when
218 		 * not employing slots.
219 		 */
220 		pold = NULL;
221 	}
222 
223 	if (pold) {
224 		*pval = input_defuzz_abs_event(*pval, *pold,
225 						dev->absinfo[code].fuzz);
226 		if (*pold == *pval)
227 			return INPUT_IGNORE_EVENT;
228 
229 		*pold = *pval;
230 	}
231 
232 	/* Flush pending "slot" event */
233 	if (is_new_slot) {
234 		dev->absinfo[ABS_MT_SLOT].value = mt->slot;
235 		return INPUT_PASS_TO_HANDLERS | INPUT_SLOT;
236 	}
237 
238 	return INPUT_PASS_TO_HANDLERS;
239 }
240 
input_get_disposition(struct input_dev * dev,unsigned int type,unsigned int code,int * pval)241 static int input_get_disposition(struct input_dev *dev,
242 			  unsigned int type, unsigned int code, int *pval)
243 {
244 	int disposition = INPUT_IGNORE_EVENT;
245 	int value = *pval;
246 
247 	/* filter-out events from inhibited devices */
248 	if (dev->inhibited)
249 		return INPUT_IGNORE_EVENT;
250 
251 	switch (type) {
252 
253 	case EV_SYN:
254 		switch (code) {
255 		case SYN_CONFIG:
256 			disposition = INPUT_PASS_TO_ALL;
257 			break;
258 
259 		case SYN_REPORT:
260 			disposition = INPUT_PASS_TO_HANDLERS | INPUT_FLUSH;
261 			break;
262 		case SYN_MT_REPORT:
263 			disposition = INPUT_PASS_TO_HANDLERS;
264 			break;
265 		}
266 		break;
267 
268 	case EV_KEY:
269 		if (is_event_supported(code, dev->keybit, KEY_MAX)) {
270 
271 			/* auto-repeat bypasses state updates */
272 			if (value == 2) {
273 				disposition = INPUT_PASS_TO_HANDLERS;
274 				break;
275 			}
276 
277 			if (!!test_bit(code, dev->key) != !!value) {
278 
279 				__change_bit(code, dev->key);
280 				disposition = INPUT_PASS_TO_HANDLERS;
281 			}
282 		}
283 		break;
284 
285 	case EV_SW:
286 		if (is_event_supported(code, dev->swbit, SW_MAX) &&
287 		    !!test_bit(code, dev->sw) != !!value) {
288 
289 			__change_bit(code, dev->sw);
290 			disposition = INPUT_PASS_TO_HANDLERS;
291 		}
292 		break;
293 
294 	case EV_ABS:
295 		if (is_event_supported(code, dev->absbit, ABS_MAX))
296 			disposition = input_handle_abs_event(dev, code, &value);
297 
298 		break;
299 
300 	case EV_REL:
301 		if (is_event_supported(code, dev->relbit, REL_MAX) && value)
302 			disposition = INPUT_PASS_TO_HANDLERS;
303 
304 		break;
305 
306 	case EV_MSC:
307 		if (is_event_supported(code, dev->mscbit, MSC_MAX))
308 			disposition = INPUT_PASS_TO_ALL;
309 
310 		break;
311 
312 	case EV_LED:
313 		if (is_event_supported(code, dev->ledbit, LED_MAX) &&
314 		    !!test_bit(code, dev->led) != !!value) {
315 
316 			__change_bit(code, dev->led);
317 			disposition = INPUT_PASS_TO_ALL;
318 		}
319 		break;
320 
321 	case EV_SND:
322 		if (is_event_supported(code, dev->sndbit, SND_MAX)) {
323 
324 			if (!!test_bit(code, dev->snd) != !!value)
325 				__change_bit(code, dev->snd);
326 			disposition = INPUT_PASS_TO_ALL;
327 		}
328 		break;
329 
330 	case EV_REP:
331 		if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
332 			dev->rep[code] = value;
333 			disposition = INPUT_PASS_TO_ALL;
334 		}
335 		break;
336 
337 	case EV_FF:
338 		if (value >= 0)
339 			disposition = INPUT_PASS_TO_ALL;
340 		break;
341 
342 	case EV_PWR:
343 		disposition = INPUT_PASS_TO_ALL;
344 		break;
345 	}
346 
347 	*pval = value;
348 	return disposition;
349 }
350 
input_event_dispose(struct input_dev * dev,int disposition,unsigned int type,unsigned int code,int value)351 static void input_event_dispose(struct input_dev *dev, int disposition,
352 				unsigned int type, unsigned int code, int value)
353 {
354 	if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event)
355 		dev->event(dev, type, code, value);
356 
357 	if (!dev->vals)
358 		return;
359 
360 	if (disposition & INPUT_PASS_TO_HANDLERS) {
361 		struct input_value *v;
362 
363 		if (disposition & INPUT_SLOT) {
364 			v = &dev->vals[dev->num_vals++];
365 			v->type = EV_ABS;
366 			v->code = ABS_MT_SLOT;
367 			v->value = dev->mt->slot;
368 		}
369 
370 		v = &dev->vals[dev->num_vals++];
371 		v->type = type;
372 		v->code = code;
373 		v->value = value;
374 	}
375 
376 	if (disposition & INPUT_FLUSH) {
377 		if (dev->num_vals >= 2)
378 			input_pass_values(dev, dev->vals, dev->num_vals);
379 		dev->num_vals = 0;
380 		/*
381 		 * Reset the timestamp on flush so we won't end up
382 		 * with a stale one. Note we only need to reset the
383 		 * monolithic one as we use its presence when deciding
384 		 * whether to generate a synthetic timestamp.
385 		 */
386 		dev->timestamp[INPUT_CLK_MONO] = ktime_set(0, 0);
387 	} else if (dev->num_vals >= dev->max_vals - 2) {
388 		dev->vals[dev->num_vals++] = input_value_sync;
389 		input_pass_values(dev, dev->vals, dev->num_vals);
390 		dev->num_vals = 0;
391 	}
392 }
393 
input_handle_event(struct input_dev * dev,unsigned int type,unsigned int code,int value)394 void input_handle_event(struct input_dev *dev,
395 			unsigned int type, unsigned int code, int value)
396 {
397 	int disposition;
398 
399 	lockdep_assert_held(&dev->event_lock);
400 
401 	disposition = input_get_disposition(dev, type, code, &value);
402 	if (disposition != INPUT_IGNORE_EVENT) {
403 		if (type != EV_SYN)
404 			add_input_randomness(type, code, value);
405 
406 		input_event_dispose(dev, disposition, type, code, value);
407 	}
408 }
409 
410 /**
411  * input_event() - report new input event
412  * @dev: device that generated the event
413  * @type: type of the event
414  * @code: event code
415  * @value: value of the event
416  *
417  * This function should be used by drivers implementing various input
418  * devices to report input events. See also input_inject_event().
419  *
420  * NOTE: input_event() may be safely used right after input device was
421  * allocated with input_allocate_device(), even before it is registered
422  * with input_register_device(), but the event will not reach any of the
423  * input handlers. Such early invocation of input_event() may be used
424  * to 'seed' initial state of a switch or initial position of absolute
425  * axis, etc.
426  */
input_event(struct input_dev * dev,unsigned int type,unsigned int code,int value)427 void input_event(struct input_dev *dev,
428 		 unsigned int type, unsigned int code, int value)
429 {
430 	unsigned long flags;
431 
432 	if (is_event_supported(type, dev->evbit, EV_MAX)) {
433 
434 		spin_lock_irqsave(&dev->event_lock, flags);
435 		input_handle_event(dev, type, code, value);
436 		spin_unlock_irqrestore(&dev->event_lock, flags);
437 	}
438 }
439 EXPORT_SYMBOL(input_event);
440 
441 /**
442  * input_inject_event() - send input event from input handler
443  * @handle: input handle to send event through
444  * @type: type of the event
445  * @code: event code
446  * @value: value of the event
447  *
448  * Similar to input_event() but will ignore event if device is
449  * "grabbed" and handle injecting event is not the one that owns
450  * the device.
451  */
input_inject_event(struct input_handle * handle,unsigned int type,unsigned int code,int value)452 void input_inject_event(struct input_handle *handle,
453 			unsigned int type, unsigned int code, int value)
454 {
455 	struct input_dev *dev = handle->dev;
456 	struct input_handle *grab;
457 	unsigned long flags;
458 
459 	if (is_event_supported(type, dev->evbit, EV_MAX)) {
460 		spin_lock_irqsave(&dev->event_lock, flags);
461 
462 		rcu_read_lock();
463 		grab = rcu_dereference(dev->grab);
464 		if (!grab || grab == handle)
465 			input_handle_event(dev, type, code, value);
466 		rcu_read_unlock();
467 
468 		spin_unlock_irqrestore(&dev->event_lock, flags);
469 	}
470 }
471 EXPORT_SYMBOL(input_inject_event);
472 
473 /**
474  * input_alloc_absinfo - allocates array of input_absinfo structs
475  * @dev: the input device emitting absolute events
476  *
477  * If the absinfo struct the caller asked for is already allocated, this
478  * functions will not do anything.
479  */
input_alloc_absinfo(struct input_dev * dev)480 void input_alloc_absinfo(struct input_dev *dev)
481 {
482 	if (dev->absinfo)
483 		return;
484 
485 	dev->absinfo = kcalloc(ABS_CNT, sizeof(*dev->absinfo), GFP_KERNEL);
486 	if (!dev->absinfo) {
487 		dev_err(dev->dev.parent ?: &dev->dev,
488 			"%s: unable to allocate memory\n", __func__);
489 		/*
490 		 * We will handle this allocation failure in
491 		 * input_register_device() when we refuse to register input
492 		 * device with ABS bits but without absinfo.
493 		 */
494 	}
495 }
496 EXPORT_SYMBOL(input_alloc_absinfo);
497 
input_set_abs_params(struct input_dev * dev,unsigned int axis,int min,int max,int fuzz,int flat)498 void input_set_abs_params(struct input_dev *dev, unsigned int axis,
499 			  int min, int max, int fuzz, int flat)
500 {
501 	struct input_absinfo *absinfo;
502 
503 	__set_bit(EV_ABS, dev->evbit);
504 	__set_bit(axis, dev->absbit);
505 
506 	input_alloc_absinfo(dev);
507 	if (!dev->absinfo)
508 		return;
509 
510 	absinfo = &dev->absinfo[axis];
511 	absinfo->minimum = min;
512 	absinfo->maximum = max;
513 	absinfo->fuzz = fuzz;
514 	absinfo->flat = flat;
515 }
516 EXPORT_SYMBOL(input_set_abs_params);
517 
518 /**
519  * input_copy_abs - Copy absinfo from one input_dev to another
520  * @dst: Destination input device to copy the abs settings to
521  * @dst_axis: ABS_* value selecting the destination axis
522  * @src: Source input device to copy the abs settings from
523  * @src_axis: ABS_* value selecting the source axis
524  *
525  * Set absinfo for the selected destination axis by copying it from
526  * the specified source input device's source axis.
527  * This is useful to e.g. setup a pen/stylus input-device for combined
528  * touchscreen/pen hardware where the pen uses the same coordinates as
529  * the touchscreen.
530  */
input_copy_abs(struct input_dev * dst,unsigned int dst_axis,const struct input_dev * src,unsigned int src_axis)531 void input_copy_abs(struct input_dev *dst, unsigned int dst_axis,
532 		    const struct input_dev *src, unsigned int src_axis)
533 {
534 	/* src must have EV_ABS and src_axis set */
535 	if (WARN_ON(!(test_bit(EV_ABS, src->evbit) &&
536 		      test_bit(src_axis, src->absbit))))
537 		return;
538 
539 	/*
540 	 * input_alloc_absinfo() may have failed for the source. Our caller is
541 	 * expected to catch this when registering the input devices, which may
542 	 * happen after the input_copy_abs() call.
543 	 */
544 	if (!src->absinfo)
545 		return;
546 
547 	input_set_capability(dst, EV_ABS, dst_axis);
548 	if (!dst->absinfo)
549 		return;
550 
551 	dst->absinfo[dst_axis] = src->absinfo[src_axis];
552 }
553 EXPORT_SYMBOL(input_copy_abs);
554 
555 /**
556  * input_grab_device - grabs device for exclusive use
557  * @handle: input handle that wants to own the device
558  *
559  * When a device is grabbed by an input handle all events generated by
560  * the device are delivered only to this handle. Also events injected
561  * by other input handles are ignored while device is grabbed.
562  */
input_grab_device(struct input_handle * handle)563 int input_grab_device(struct input_handle *handle)
564 {
565 	struct input_dev *dev = handle->dev;
566 	int retval;
567 
568 	retval = mutex_lock_interruptible(&dev->mutex);
569 	if (retval)
570 		return retval;
571 
572 	if (dev->grab) {
573 		retval = -EBUSY;
574 		goto out;
575 	}
576 
577 	rcu_assign_pointer(dev->grab, handle);
578 
579  out:
580 	mutex_unlock(&dev->mutex);
581 	return retval;
582 }
583 EXPORT_SYMBOL(input_grab_device);
584 
__input_release_device(struct input_handle * handle)585 static void __input_release_device(struct input_handle *handle)
586 {
587 	struct input_dev *dev = handle->dev;
588 	struct input_handle *grabber;
589 
590 	grabber = rcu_dereference_protected(dev->grab,
591 					    lockdep_is_held(&dev->mutex));
592 	if (grabber == handle) {
593 		rcu_assign_pointer(dev->grab, NULL);
594 		/* Make sure input_pass_values() notices that grab is gone */
595 		synchronize_rcu();
596 
597 		list_for_each_entry(handle, &dev->h_list, d_node)
598 			if (handle->open && handle->handler->start)
599 				handle->handler->start(handle);
600 	}
601 }
602 
603 /**
604  * input_release_device - release previously grabbed device
605  * @handle: input handle that owns the device
606  *
607  * Releases previously grabbed device so that other input handles can
608  * start receiving input events. Upon release all handlers attached
609  * to the device have their start() method called so they have a change
610  * to synchronize device state with the rest of the system.
611  */
input_release_device(struct input_handle * handle)612 void input_release_device(struct input_handle *handle)
613 {
614 	struct input_dev *dev = handle->dev;
615 
616 	mutex_lock(&dev->mutex);
617 	__input_release_device(handle);
618 	mutex_unlock(&dev->mutex);
619 }
620 EXPORT_SYMBOL(input_release_device);
621 
622 /**
623  * input_open_device - open input device
624  * @handle: handle through which device is being accessed
625  *
626  * This function should be called by input handlers when they
627  * want to start receive events from given input device.
628  */
input_open_device(struct input_handle * handle)629 int input_open_device(struct input_handle *handle)
630 {
631 	struct input_dev *dev = handle->dev;
632 	int retval;
633 
634 	retval = mutex_lock_interruptible(&dev->mutex);
635 	if (retval)
636 		return retval;
637 
638 	if (dev->going_away) {
639 		retval = -ENODEV;
640 		goto out;
641 	}
642 
643 	handle->open++;
644 
645 	if (dev->users++ || dev->inhibited) {
646 		/*
647 		 * Device is already opened and/or inhibited,
648 		 * so we can exit immediately and report success.
649 		 */
650 		goto out;
651 	}
652 
653 	if (dev->open) {
654 		retval = dev->open(dev);
655 		if (retval) {
656 			dev->users--;
657 			handle->open--;
658 			/*
659 			 * Make sure we are not delivering any more events
660 			 * through this handle
661 			 */
662 			synchronize_rcu();
663 			goto out;
664 		}
665 	}
666 
667 	if (dev->poller)
668 		input_dev_poller_start(dev->poller);
669 
670  out:
671 	mutex_unlock(&dev->mutex);
672 	return retval;
673 }
674 EXPORT_SYMBOL(input_open_device);
675 
input_flush_device(struct input_handle * handle,struct file * file)676 int input_flush_device(struct input_handle *handle, struct file *file)
677 {
678 	struct input_dev *dev = handle->dev;
679 	int retval;
680 
681 	retval = mutex_lock_interruptible(&dev->mutex);
682 	if (retval)
683 		return retval;
684 
685 	if (dev->flush)
686 		retval = dev->flush(dev, file);
687 
688 	mutex_unlock(&dev->mutex);
689 	return retval;
690 }
691 EXPORT_SYMBOL(input_flush_device);
692 
693 /**
694  * input_close_device - close input device
695  * @handle: handle through which device is being accessed
696  *
697  * This function should be called by input handlers when they
698  * want to stop receive events from given input device.
699  */
input_close_device(struct input_handle * handle)700 void input_close_device(struct input_handle *handle)
701 {
702 	struct input_dev *dev = handle->dev;
703 
704 	mutex_lock(&dev->mutex);
705 
706 	__input_release_device(handle);
707 
708 	if (!--dev->users && !dev->inhibited) {
709 		if (dev->poller)
710 			input_dev_poller_stop(dev->poller);
711 		if (dev->close)
712 			dev->close(dev);
713 	}
714 
715 	if (!--handle->open) {
716 		/*
717 		 * synchronize_rcu() makes sure that input_pass_values()
718 		 * completed and that no more input events are delivered
719 		 * through this handle
720 		 */
721 		synchronize_rcu();
722 	}
723 
724 	mutex_unlock(&dev->mutex);
725 }
726 EXPORT_SYMBOL(input_close_device);
727 
728 /*
729  * Simulate keyup events for all keys that are marked as pressed.
730  * The function must be called with dev->event_lock held.
731  */
input_dev_release_keys(struct input_dev * dev)732 static bool input_dev_release_keys(struct input_dev *dev)
733 {
734 	bool need_sync = false;
735 	int code;
736 
737 	lockdep_assert_held(&dev->event_lock);
738 
739 	if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
740 		for_each_set_bit(code, dev->key, KEY_CNT) {
741 			input_handle_event(dev, EV_KEY, code, 0);
742 			need_sync = true;
743 		}
744 	}
745 
746 	return need_sync;
747 }
748 
749 /*
750  * Prepare device for unregistering
751  */
input_disconnect_device(struct input_dev * dev)752 static void input_disconnect_device(struct input_dev *dev)
753 {
754 	struct input_handle *handle;
755 
756 	/*
757 	 * Mark device as going away. Note that we take dev->mutex here
758 	 * not to protect access to dev->going_away but rather to ensure
759 	 * that there are no threads in the middle of input_open_device()
760 	 */
761 	mutex_lock(&dev->mutex);
762 	dev->going_away = true;
763 	mutex_unlock(&dev->mutex);
764 
765 	spin_lock_irq(&dev->event_lock);
766 
767 	/*
768 	 * Simulate keyup events for all pressed keys so that handlers
769 	 * are not left with "stuck" keys. The driver may continue
770 	 * generate events even after we done here but they will not
771 	 * reach any handlers.
772 	 */
773 	if (input_dev_release_keys(dev))
774 		input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
775 
776 	list_for_each_entry(handle, &dev->h_list, d_node)
777 		handle->open = 0;
778 
779 	spin_unlock_irq(&dev->event_lock);
780 }
781 
782 /**
783  * input_scancode_to_scalar() - converts scancode in &struct input_keymap_entry
784  * @ke: keymap entry containing scancode to be converted.
785  * @scancode: pointer to the location where converted scancode should
786  *	be stored.
787  *
788  * This function is used to convert scancode stored in &struct keymap_entry
789  * into scalar form understood by legacy keymap handling methods. These
790  * methods expect scancodes to be represented as 'unsigned int'.
791  */
input_scancode_to_scalar(const struct input_keymap_entry * ke,unsigned int * scancode)792 int input_scancode_to_scalar(const struct input_keymap_entry *ke,
793 			     unsigned int *scancode)
794 {
795 	switch (ke->len) {
796 	case 1:
797 		*scancode = *((u8 *)ke->scancode);
798 		break;
799 
800 	case 2:
801 		*scancode = *((u16 *)ke->scancode);
802 		break;
803 
804 	case 4:
805 		*scancode = *((u32 *)ke->scancode);
806 		break;
807 
808 	default:
809 		return -EINVAL;
810 	}
811 
812 	return 0;
813 }
814 EXPORT_SYMBOL(input_scancode_to_scalar);
815 
816 /*
817  * Those routines handle the default case where no [gs]etkeycode() is
818  * defined. In this case, an array indexed by the scancode is used.
819  */
820 
input_fetch_keycode(struct input_dev * dev,unsigned int index)821 static unsigned int input_fetch_keycode(struct input_dev *dev,
822 					unsigned int index)
823 {
824 	switch (dev->keycodesize) {
825 	case 1:
826 		return ((u8 *)dev->keycode)[index];
827 
828 	case 2:
829 		return ((u16 *)dev->keycode)[index];
830 
831 	default:
832 		return ((u32 *)dev->keycode)[index];
833 	}
834 }
835 
input_default_getkeycode(struct input_dev * dev,struct input_keymap_entry * ke)836 static int input_default_getkeycode(struct input_dev *dev,
837 				    struct input_keymap_entry *ke)
838 {
839 	unsigned int index;
840 	int error;
841 
842 	if (!dev->keycodesize)
843 		return -EINVAL;
844 
845 	if (ke->flags & INPUT_KEYMAP_BY_INDEX)
846 		index = ke->index;
847 	else {
848 		error = input_scancode_to_scalar(ke, &index);
849 		if (error)
850 			return error;
851 	}
852 
853 	if (index >= dev->keycodemax)
854 		return -EINVAL;
855 
856 	ke->keycode = input_fetch_keycode(dev, index);
857 	ke->index = index;
858 	ke->len = sizeof(index);
859 	memcpy(ke->scancode, &index, sizeof(index));
860 
861 	return 0;
862 }
863 
input_default_setkeycode(struct input_dev * dev,const struct input_keymap_entry * ke,unsigned int * old_keycode)864 static int input_default_setkeycode(struct input_dev *dev,
865 				    const struct input_keymap_entry *ke,
866 				    unsigned int *old_keycode)
867 {
868 	unsigned int index;
869 	int error;
870 	int i;
871 
872 	if (!dev->keycodesize)
873 		return -EINVAL;
874 
875 	if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
876 		index = ke->index;
877 	} else {
878 		error = input_scancode_to_scalar(ke, &index);
879 		if (error)
880 			return error;
881 	}
882 
883 	if (index >= dev->keycodemax)
884 		return -EINVAL;
885 
886 	if (dev->keycodesize < sizeof(ke->keycode) &&
887 			(ke->keycode >> (dev->keycodesize * 8)))
888 		return -EINVAL;
889 
890 	switch (dev->keycodesize) {
891 		case 1: {
892 			u8 *k = (u8 *)dev->keycode;
893 			*old_keycode = k[index];
894 			k[index] = ke->keycode;
895 			break;
896 		}
897 		case 2: {
898 			u16 *k = (u16 *)dev->keycode;
899 			*old_keycode = k[index];
900 			k[index] = ke->keycode;
901 			break;
902 		}
903 		default: {
904 			u32 *k = (u32 *)dev->keycode;
905 			*old_keycode = k[index];
906 			k[index] = ke->keycode;
907 			break;
908 		}
909 	}
910 
911 	if (*old_keycode <= KEY_MAX) {
912 		__clear_bit(*old_keycode, dev->keybit);
913 		for (i = 0; i < dev->keycodemax; i++) {
914 			if (input_fetch_keycode(dev, i) == *old_keycode) {
915 				__set_bit(*old_keycode, dev->keybit);
916 				/* Setting the bit twice is useless, so break */
917 				break;
918 			}
919 		}
920 	}
921 
922 	__set_bit(ke->keycode, dev->keybit);
923 	return 0;
924 }
925 
926 /**
927  * input_get_keycode - retrieve keycode currently mapped to a given scancode
928  * @dev: input device which keymap is being queried
929  * @ke: keymap entry
930  *
931  * This function should be called by anyone interested in retrieving current
932  * keymap. Presently evdev handlers use it.
933  */
input_get_keycode(struct input_dev * dev,struct input_keymap_entry * ke)934 int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke)
935 {
936 	unsigned long flags;
937 	int retval;
938 
939 	spin_lock_irqsave(&dev->event_lock, flags);
940 	retval = dev->getkeycode(dev, ke);
941 	spin_unlock_irqrestore(&dev->event_lock, flags);
942 
943 	return retval;
944 }
945 EXPORT_SYMBOL(input_get_keycode);
946 
947 /**
948  * input_set_keycode - attribute a keycode to a given scancode
949  * @dev: input device which keymap is being updated
950  * @ke: new keymap entry
951  *
952  * This function should be called by anyone needing to update current
953  * keymap. Presently keyboard and evdev handlers use it.
954  */
input_set_keycode(struct input_dev * dev,const struct input_keymap_entry * ke)955 int input_set_keycode(struct input_dev *dev,
956 		      const struct input_keymap_entry *ke)
957 {
958 	unsigned long flags;
959 	unsigned int old_keycode;
960 	int retval;
961 
962 	if (ke->keycode > KEY_MAX)
963 		return -EINVAL;
964 
965 	spin_lock_irqsave(&dev->event_lock, flags);
966 
967 	retval = dev->setkeycode(dev, ke, &old_keycode);
968 	if (retval)
969 		goto out;
970 
971 	/* Make sure KEY_RESERVED did not get enabled. */
972 	__clear_bit(KEY_RESERVED, dev->keybit);
973 
974 	/*
975 	 * Simulate keyup event if keycode is not present
976 	 * in the keymap anymore
977 	 */
978 	if (old_keycode > KEY_MAX) {
979 		dev_warn(dev->dev.parent ?: &dev->dev,
980 			 "%s: got too big old keycode %#x\n",
981 			 __func__, old_keycode);
982 	} else if (test_bit(EV_KEY, dev->evbit) &&
983 		   !is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
984 		   __test_and_clear_bit(old_keycode, dev->key)) {
985 		/*
986 		 * We have to use input_event_dispose() here directly instead
987 		 * of input_handle_event() because the key we want to release
988 		 * here is considered no longer supported by the device and
989 		 * input_handle_event() will ignore it.
990 		 */
991 		input_event_dispose(dev, INPUT_PASS_TO_HANDLERS,
992 				    EV_KEY, old_keycode, 0);
993 		input_event_dispose(dev, INPUT_PASS_TO_HANDLERS | INPUT_FLUSH,
994 				    EV_SYN, SYN_REPORT, 1);
995 	}
996 
997  out:
998 	spin_unlock_irqrestore(&dev->event_lock, flags);
999 
1000 	return retval;
1001 }
1002 EXPORT_SYMBOL(input_set_keycode);
1003 
input_match_device_id(const struct input_dev * dev,const struct input_device_id * id)1004 bool input_match_device_id(const struct input_dev *dev,
1005 			   const struct input_device_id *id)
1006 {
1007 	if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
1008 		if (id->bustype != dev->id.bustype)
1009 			return false;
1010 
1011 	if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
1012 		if (id->vendor != dev->id.vendor)
1013 			return false;
1014 
1015 	if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
1016 		if (id->product != dev->id.product)
1017 			return false;
1018 
1019 	if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
1020 		if (id->version != dev->id.version)
1021 			return false;
1022 
1023 	if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX) ||
1024 	    !bitmap_subset(id->keybit, dev->keybit, KEY_MAX) ||
1025 	    !bitmap_subset(id->relbit, dev->relbit, REL_MAX) ||
1026 	    !bitmap_subset(id->absbit, dev->absbit, ABS_MAX) ||
1027 	    !bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX) ||
1028 	    !bitmap_subset(id->ledbit, dev->ledbit, LED_MAX) ||
1029 	    !bitmap_subset(id->sndbit, dev->sndbit, SND_MAX) ||
1030 	    !bitmap_subset(id->ffbit, dev->ffbit, FF_MAX) ||
1031 	    !bitmap_subset(id->swbit, dev->swbit, SW_MAX) ||
1032 	    !bitmap_subset(id->propbit, dev->propbit, INPUT_PROP_MAX)) {
1033 		return false;
1034 	}
1035 
1036 	return true;
1037 }
1038 EXPORT_SYMBOL(input_match_device_id);
1039 
input_match_device(struct input_handler * handler,struct input_dev * dev)1040 static const struct input_device_id *input_match_device(struct input_handler *handler,
1041 							struct input_dev *dev)
1042 {
1043 	const struct input_device_id *id;
1044 
1045 	for (id = handler->id_table; id->flags || id->driver_info; id++) {
1046 		if (input_match_device_id(dev, id) &&
1047 		    (!handler->match || handler->match(handler, dev))) {
1048 			return id;
1049 		}
1050 	}
1051 
1052 	return NULL;
1053 }
1054 
input_attach_handler(struct input_dev * dev,struct input_handler * handler)1055 static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
1056 {
1057 	const struct input_device_id *id;
1058 	int error;
1059 
1060 	id = input_match_device(handler, dev);
1061 	if (!id)
1062 		return -ENODEV;
1063 
1064 	error = handler->connect(handler, dev, id);
1065 	if (error && error != -ENODEV)
1066 		pr_err("failed to attach handler %s to device %s, error: %d\n",
1067 		       handler->name, kobject_name(&dev->dev.kobj), error);
1068 
1069 	return error;
1070 }
1071 
1072 #ifdef CONFIG_COMPAT
1073 
input_bits_to_string(char * buf,int buf_size,unsigned long bits,bool skip_empty)1074 static int input_bits_to_string(char *buf, int buf_size,
1075 				unsigned long bits, bool skip_empty)
1076 {
1077 	int len = 0;
1078 
1079 	if (in_compat_syscall()) {
1080 		u32 dword = bits >> 32;
1081 		if (dword || !skip_empty)
1082 			len += snprintf(buf, buf_size, "%x ", dword);
1083 
1084 		dword = bits & 0xffffffffUL;
1085 		if (dword || !skip_empty || len)
1086 			len += snprintf(buf + len, max(buf_size - len, 0),
1087 					"%x", dword);
1088 	} else {
1089 		if (bits || !skip_empty)
1090 			len += snprintf(buf, buf_size, "%lx", bits);
1091 	}
1092 
1093 	return len;
1094 }
1095 
1096 #else /* !CONFIG_COMPAT */
1097 
input_bits_to_string(char * buf,int buf_size,unsigned long bits,bool skip_empty)1098 static int input_bits_to_string(char *buf, int buf_size,
1099 				unsigned long bits, bool skip_empty)
1100 {
1101 	return bits || !skip_empty ?
1102 		snprintf(buf, buf_size, "%lx", bits) : 0;
1103 }
1104 
1105 #endif
1106 
1107 #ifdef CONFIG_PROC_FS
1108 
1109 static struct proc_dir_entry *proc_bus_input_dir;
1110 static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
1111 static int input_devices_state;
1112 
input_wakeup_procfs_readers(void)1113 static inline void input_wakeup_procfs_readers(void)
1114 {
1115 	input_devices_state++;
1116 	wake_up(&input_devices_poll_wait);
1117 }
1118 
input_proc_devices_poll(struct file * file,poll_table * wait)1119 static __poll_t input_proc_devices_poll(struct file *file, poll_table *wait)
1120 {
1121 	poll_wait(file, &input_devices_poll_wait, wait);
1122 	if (file->f_version != input_devices_state) {
1123 		file->f_version = input_devices_state;
1124 		return EPOLLIN | EPOLLRDNORM;
1125 	}
1126 
1127 	return 0;
1128 }
1129 
1130 union input_seq_state {
1131 	struct {
1132 		unsigned short pos;
1133 		bool mutex_acquired;
1134 	};
1135 	void *p;
1136 };
1137 
input_devices_seq_start(struct seq_file * seq,loff_t * pos)1138 static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
1139 {
1140 	union input_seq_state *state = (union input_seq_state *)&seq->private;
1141 	int error;
1142 
1143 	/* We need to fit into seq->private pointer */
1144 	BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
1145 
1146 	error = mutex_lock_interruptible(&input_mutex);
1147 	if (error) {
1148 		state->mutex_acquired = false;
1149 		return ERR_PTR(error);
1150 	}
1151 
1152 	state->mutex_acquired = true;
1153 
1154 	return seq_list_start(&input_dev_list, *pos);
1155 }
1156 
input_devices_seq_next(struct seq_file * seq,void * v,loff_t * pos)1157 static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1158 {
1159 	return seq_list_next(v, &input_dev_list, pos);
1160 }
1161 
input_seq_stop(struct seq_file * seq,void * v)1162 static void input_seq_stop(struct seq_file *seq, void *v)
1163 {
1164 	union input_seq_state *state = (union input_seq_state *)&seq->private;
1165 
1166 	if (state->mutex_acquired)
1167 		mutex_unlock(&input_mutex);
1168 }
1169 
input_seq_print_bitmap(struct seq_file * seq,const char * name,unsigned long * bitmap,int max)1170 static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
1171 				   unsigned long *bitmap, int max)
1172 {
1173 	int i;
1174 	bool skip_empty = true;
1175 	char buf[18];
1176 
1177 	seq_printf(seq, "B: %s=", name);
1178 
1179 	for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
1180 		if (input_bits_to_string(buf, sizeof(buf),
1181 					 bitmap[i], skip_empty)) {
1182 			skip_empty = false;
1183 			seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
1184 		}
1185 	}
1186 
1187 	/*
1188 	 * If no output was produced print a single 0.
1189 	 */
1190 	if (skip_empty)
1191 		seq_putc(seq, '0');
1192 
1193 	seq_putc(seq, '\n');
1194 }
1195 
input_devices_seq_show(struct seq_file * seq,void * v)1196 static int input_devices_seq_show(struct seq_file *seq, void *v)
1197 {
1198 	struct input_dev *dev = container_of(v, struct input_dev, node);
1199 	const char *path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
1200 	struct input_handle *handle;
1201 
1202 	seq_printf(seq, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
1203 		   dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);
1204 
1205 	seq_printf(seq, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
1206 	seq_printf(seq, "P: Phys=%s\n", dev->phys ? dev->phys : "");
1207 	seq_printf(seq, "S: Sysfs=%s\n", path ? path : "");
1208 	seq_printf(seq, "U: Uniq=%s\n", dev->uniq ? dev->uniq : "");
1209 	seq_puts(seq, "H: Handlers=");
1210 
1211 	list_for_each_entry(handle, &dev->h_list, d_node)
1212 		seq_printf(seq, "%s ", handle->name);
1213 	seq_putc(seq, '\n');
1214 
1215 	input_seq_print_bitmap(seq, "PROP", dev->propbit, INPUT_PROP_MAX);
1216 
1217 	input_seq_print_bitmap(seq, "EV", dev->evbit, EV_MAX);
1218 	if (test_bit(EV_KEY, dev->evbit))
1219 		input_seq_print_bitmap(seq, "KEY", dev->keybit, KEY_MAX);
1220 	if (test_bit(EV_REL, dev->evbit))
1221 		input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
1222 	if (test_bit(EV_ABS, dev->evbit))
1223 		input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
1224 	if (test_bit(EV_MSC, dev->evbit))
1225 		input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
1226 	if (test_bit(EV_LED, dev->evbit))
1227 		input_seq_print_bitmap(seq, "LED", dev->ledbit, LED_MAX);
1228 	if (test_bit(EV_SND, dev->evbit))
1229 		input_seq_print_bitmap(seq, "SND", dev->sndbit, SND_MAX);
1230 	if (test_bit(EV_FF, dev->evbit))
1231 		input_seq_print_bitmap(seq, "FF", dev->ffbit, FF_MAX);
1232 	if (test_bit(EV_SW, dev->evbit))
1233 		input_seq_print_bitmap(seq, "SW", dev->swbit, SW_MAX);
1234 
1235 	seq_putc(seq, '\n');
1236 
1237 	kfree(path);
1238 	return 0;
1239 }
1240 
1241 static const struct seq_operations input_devices_seq_ops = {
1242 	.start	= input_devices_seq_start,
1243 	.next	= input_devices_seq_next,
1244 	.stop	= input_seq_stop,
1245 	.show	= input_devices_seq_show,
1246 };
1247 
input_proc_devices_open(struct inode * inode,struct file * file)1248 static int input_proc_devices_open(struct inode *inode, struct file *file)
1249 {
1250 	return seq_open(file, &input_devices_seq_ops);
1251 }
1252 
1253 static const struct proc_ops input_devices_proc_ops = {
1254 	.proc_open	= input_proc_devices_open,
1255 	.proc_poll	= input_proc_devices_poll,
1256 	.proc_read	= seq_read,
1257 	.proc_lseek	= seq_lseek,
1258 	.proc_release	= seq_release,
1259 };
1260 
input_handlers_seq_start(struct seq_file * seq,loff_t * pos)1261 static void *input_handlers_seq_start(struct seq_file *seq, loff_t *pos)
1262 {
1263 	union input_seq_state *state = (union input_seq_state *)&seq->private;
1264 	int error;
1265 
1266 	/* We need to fit into seq->private pointer */
1267 	BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
1268 
1269 	error = mutex_lock_interruptible(&input_mutex);
1270 	if (error) {
1271 		state->mutex_acquired = false;
1272 		return ERR_PTR(error);
1273 	}
1274 
1275 	state->mutex_acquired = true;
1276 	state->pos = *pos;
1277 
1278 	return seq_list_start(&input_handler_list, *pos);
1279 }
1280 
input_handlers_seq_next(struct seq_file * seq,void * v,loff_t * pos)1281 static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1282 {
1283 	union input_seq_state *state = (union input_seq_state *)&seq->private;
1284 
1285 	state->pos = *pos + 1;
1286 	return seq_list_next(v, &input_handler_list, pos);
1287 }
1288 
input_handlers_seq_show(struct seq_file * seq,void * v)1289 static int input_handlers_seq_show(struct seq_file *seq, void *v)
1290 {
1291 	struct input_handler *handler = container_of(v, struct input_handler, node);
1292 	union input_seq_state *state = (union input_seq_state *)&seq->private;
1293 
1294 	seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
1295 	if (handler->filter)
1296 		seq_puts(seq, " (filter)");
1297 	if (handler->legacy_minors)
1298 		seq_printf(seq, " Minor=%d", handler->minor);
1299 	seq_putc(seq, '\n');
1300 
1301 	return 0;
1302 }
1303 
1304 static const struct seq_operations input_handlers_seq_ops = {
1305 	.start	= input_handlers_seq_start,
1306 	.next	= input_handlers_seq_next,
1307 	.stop	= input_seq_stop,
1308 	.show	= input_handlers_seq_show,
1309 };
1310 
input_proc_handlers_open(struct inode * inode,struct file * file)1311 static int input_proc_handlers_open(struct inode *inode, struct file *file)
1312 {
1313 	return seq_open(file, &input_handlers_seq_ops);
1314 }
1315 
1316 static const struct proc_ops input_handlers_proc_ops = {
1317 	.proc_open	= input_proc_handlers_open,
1318 	.proc_read	= seq_read,
1319 	.proc_lseek	= seq_lseek,
1320 	.proc_release	= seq_release,
1321 };
1322 
input_proc_init(void)1323 static int __init input_proc_init(void)
1324 {
1325 	struct proc_dir_entry *entry;
1326 
1327 	proc_bus_input_dir = proc_mkdir("bus/input", NULL);
1328 	if (!proc_bus_input_dir)
1329 		return -ENOMEM;
1330 
1331 	entry = proc_create("devices", 0, proc_bus_input_dir,
1332 			    &input_devices_proc_ops);
1333 	if (!entry)
1334 		goto fail1;
1335 
1336 	entry = proc_create("handlers", 0, proc_bus_input_dir,
1337 			    &input_handlers_proc_ops);
1338 	if (!entry)
1339 		goto fail2;
1340 
1341 	return 0;
1342 
1343  fail2:	remove_proc_entry("devices", proc_bus_input_dir);
1344  fail1: remove_proc_entry("bus/input", NULL);
1345 	return -ENOMEM;
1346 }
1347 
input_proc_exit(void)1348 static void input_proc_exit(void)
1349 {
1350 	remove_proc_entry("devices", proc_bus_input_dir);
1351 	remove_proc_entry("handlers", proc_bus_input_dir);
1352 	remove_proc_entry("bus/input", NULL);
1353 }
1354 
1355 #else /* !CONFIG_PROC_FS */
input_wakeup_procfs_readers(void)1356 static inline void input_wakeup_procfs_readers(void) { }
input_proc_init(void)1357 static inline int input_proc_init(void) { return 0; }
input_proc_exit(void)1358 static inline void input_proc_exit(void) { }
1359 #endif
1360 
1361 #define INPUT_DEV_STRING_ATTR_SHOW(name)				\
1362 static ssize_t input_dev_show_##name(struct device *dev,		\
1363 				     struct device_attribute *attr,	\
1364 				     char *buf)				\
1365 {									\
1366 	struct input_dev *input_dev = to_input_dev(dev);		\
1367 									\
1368 	return scnprintf(buf, PAGE_SIZE, "%s\n",			\
1369 			 input_dev->name ? input_dev->name : "");	\
1370 }									\
1371 static DEVICE_ATTR(name, S_IRUGO, input_dev_show_##name, NULL)
1372 
1373 INPUT_DEV_STRING_ATTR_SHOW(name);
1374 INPUT_DEV_STRING_ATTR_SHOW(phys);
1375 INPUT_DEV_STRING_ATTR_SHOW(uniq);
1376 
input_print_modalias_bits(char * buf,int size,char name,const unsigned long * bm,unsigned int min_bit,unsigned int max_bit)1377 static int input_print_modalias_bits(char *buf, int size,
1378 				     char name, const unsigned long *bm,
1379 				     unsigned int min_bit, unsigned int max_bit)
1380 {
1381 	int bit = min_bit;
1382 	int len = 0;
1383 
1384 	len += snprintf(buf, max(size, 0), "%c", name);
1385 	for_each_set_bit_from(bit, bm, max_bit)
1386 		len += snprintf(buf + len, max(size - len, 0), "%X,", bit);
1387 	return len;
1388 }
1389 
input_print_modalias_parts(char * buf,int size,int full_len,const struct input_dev * id)1390 static int input_print_modalias_parts(char *buf, int size, int full_len,
1391 				      const struct input_dev *id)
1392 {
1393 	int len, klen, remainder, space;
1394 
1395 	len = snprintf(buf, max(size, 0),
1396 		       "input:b%04Xv%04Xp%04Xe%04X-",
1397 		       id->id.bustype, id->id.vendor,
1398 		       id->id.product, id->id.version);
1399 
1400 	len += input_print_modalias_bits(buf + len, size - len,
1401 				'e', id->evbit, 0, EV_MAX);
1402 
1403 	/*
1404 	 * Calculate the remaining space in the buffer making sure we
1405 	 * have place for the terminating 0.
1406 	 */
1407 	space = max(size - (len + 1), 0);
1408 
1409 	klen = input_print_modalias_bits(buf + len, size - len,
1410 				'k', id->keybit, KEY_MIN_INTERESTING, KEY_MAX);
1411 	len += klen;
1412 
1413 	/*
1414 	 * If we have more data than we can fit in the buffer, check
1415 	 * if we can trim key data to fit in the rest. We will indicate
1416 	 * that key data is incomplete by adding "+" sign at the end, like
1417 	 * this: * "k1,2,3,45,+,".
1418 	 *
1419 	 * Note that we shortest key info (if present) is "k+," so we
1420 	 * can only try to trim if key data is longer than that.
1421 	 */
1422 	if (full_len && size < full_len + 1 && klen > 3) {
1423 		remainder = full_len - len;
1424 		/*
1425 		 * We can only trim if we have space for the remainder
1426 		 * and also for at least "k+," which is 3 more characters.
1427 		 */
1428 		if (remainder <= space - 3) {
1429 			/*
1430 			 * We are guaranteed to have 'k' in the buffer, so
1431 			 * we need at least 3 additional bytes for storing
1432 			 * "+," in addition to the remainder.
1433 			 */
1434 			for (int i = size - 1 - remainder - 3; i >= 0; i--) {
1435 				if (buf[i] == 'k' || buf[i] == ',') {
1436 					strcpy(buf + i + 1, "+,");
1437 					len = i + 3; /* Not counting '\0' */
1438 					break;
1439 				}
1440 			}
1441 		}
1442 	}
1443 
1444 	len += input_print_modalias_bits(buf + len, size - len,
1445 				'r', id->relbit, 0, REL_MAX);
1446 	len += input_print_modalias_bits(buf + len, size - len,
1447 				'a', id->absbit, 0, ABS_MAX);
1448 	len += input_print_modalias_bits(buf + len, size - len,
1449 				'm', id->mscbit, 0, MSC_MAX);
1450 	len += input_print_modalias_bits(buf + len, size - len,
1451 				'l', id->ledbit, 0, LED_MAX);
1452 	len += input_print_modalias_bits(buf + len, size - len,
1453 				's', id->sndbit, 0, SND_MAX);
1454 	len += input_print_modalias_bits(buf + len, size - len,
1455 				'f', id->ffbit, 0, FF_MAX);
1456 	len += input_print_modalias_bits(buf + len, size - len,
1457 				'w', id->swbit, 0, SW_MAX);
1458 
1459 	return len;
1460 }
1461 
input_print_modalias(char * buf,int size,const struct input_dev * id)1462 static int input_print_modalias(char *buf, int size, const struct input_dev *id)
1463 {
1464 	int full_len;
1465 
1466 	/*
1467 	 * Printing is done in 2 passes: first one figures out total length
1468 	 * needed for the modalias string, second one will try to trim key
1469 	 * data in case when buffer is too small for the entire modalias.
1470 	 * If the buffer is too small regardless, it will fill as much as it
1471 	 * can (without trimming key data) into the buffer and leave it to
1472 	 * the caller to figure out what to do with the result.
1473 	 */
1474 	full_len = input_print_modalias_parts(NULL, 0, 0, id);
1475 	return input_print_modalias_parts(buf, size, full_len, id);
1476 }
1477 
input_dev_show_modalias(struct device * dev,struct device_attribute * attr,char * buf)1478 static ssize_t input_dev_show_modalias(struct device *dev,
1479 				       struct device_attribute *attr,
1480 				       char *buf)
1481 {
1482 	struct input_dev *id = to_input_dev(dev);
1483 	ssize_t len;
1484 
1485 	len = input_print_modalias(buf, PAGE_SIZE, id);
1486 	if (len < PAGE_SIZE - 2)
1487 		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
1488 
1489 	return min_t(int, len, PAGE_SIZE);
1490 }
1491 static DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
1492 
1493 static int input_print_bitmap(char *buf, int buf_size, const unsigned long *bitmap,
1494 			      int max, int add_cr);
1495 
input_dev_show_properties(struct device * dev,struct device_attribute * attr,char * buf)1496 static ssize_t input_dev_show_properties(struct device *dev,
1497 					 struct device_attribute *attr,
1498 					 char *buf)
1499 {
1500 	struct input_dev *input_dev = to_input_dev(dev);
1501 	int len = input_print_bitmap(buf, PAGE_SIZE, input_dev->propbit,
1502 				     INPUT_PROP_MAX, true);
1503 	return min_t(int, len, PAGE_SIZE);
1504 }
1505 static DEVICE_ATTR(properties, S_IRUGO, input_dev_show_properties, NULL);
1506 
1507 static int input_inhibit_device(struct input_dev *dev);
1508 static int input_uninhibit_device(struct input_dev *dev);
1509 
inhibited_show(struct device * dev,struct device_attribute * attr,char * buf)1510 static ssize_t inhibited_show(struct device *dev,
1511 			      struct device_attribute *attr,
1512 			      char *buf)
1513 {
1514 	struct input_dev *input_dev = to_input_dev(dev);
1515 
1516 	return scnprintf(buf, PAGE_SIZE, "%d\n", input_dev->inhibited);
1517 }
1518 
inhibited_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)1519 static ssize_t inhibited_store(struct device *dev,
1520 			       struct device_attribute *attr, const char *buf,
1521 			       size_t len)
1522 {
1523 	struct input_dev *input_dev = to_input_dev(dev);
1524 	ssize_t rv;
1525 	bool inhibited;
1526 
1527 	if (kstrtobool(buf, &inhibited))
1528 		return -EINVAL;
1529 
1530 	if (inhibited)
1531 		rv = input_inhibit_device(input_dev);
1532 	else
1533 		rv = input_uninhibit_device(input_dev);
1534 
1535 	if (rv != 0)
1536 		return rv;
1537 
1538 	return len;
1539 }
1540 
1541 static DEVICE_ATTR_RW(inhibited);
1542 
1543 static struct attribute *input_dev_attrs[] = {
1544 	&dev_attr_name.attr,
1545 	&dev_attr_phys.attr,
1546 	&dev_attr_uniq.attr,
1547 	&dev_attr_modalias.attr,
1548 	&dev_attr_properties.attr,
1549 	&dev_attr_inhibited.attr,
1550 	NULL
1551 };
1552 
1553 static const struct attribute_group input_dev_attr_group = {
1554 	.attrs	= input_dev_attrs,
1555 };
1556 
1557 #define INPUT_DEV_ID_ATTR(name)						\
1558 static ssize_t input_dev_show_id_##name(struct device *dev,		\
1559 					struct device_attribute *attr,	\
1560 					char *buf)			\
1561 {									\
1562 	struct input_dev *input_dev = to_input_dev(dev);		\
1563 	return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name);	\
1564 }									\
1565 static DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL)
1566 
1567 INPUT_DEV_ID_ATTR(bustype);
1568 INPUT_DEV_ID_ATTR(vendor);
1569 INPUT_DEV_ID_ATTR(product);
1570 INPUT_DEV_ID_ATTR(version);
1571 
1572 static struct attribute *input_dev_id_attrs[] = {
1573 	&dev_attr_bustype.attr,
1574 	&dev_attr_vendor.attr,
1575 	&dev_attr_product.attr,
1576 	&dev_attr_version.attr,
1577 	NULL
1578 };
1579 
1580 static const struct attribute_group input_dev_id_attr_group = {
1581 	.name	= "id",
1582 	.attrs	= input_dev_id_attrs,
1583 };
1584 
input_print_bitmap(char * buf,int buf_size,const unsigned long * bitmap,int max,int add_cr)1585 static int input_print_bitmap(char *buf, int buf_size, const unsigned long *bitmap,
1586 			      int max, int add_cr)
1587 {
1588 	int i;
1589 	int len = 0;
1590 	bool skip_empty = true;
1591 
1592 	for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
1593 		len += input_bits_to_string(buf + len, max(buf_size - len, 0),
1594 					    bitmap[i], skip_empty);
1595 		if (len) {
1596 			skip_empty = false;
1597 			if (i > 0)
1598 				len += snprintf(buf + len, max(buf_size - len, 0), " ");
1599 		}
1600 	}
1601 
1602 	/*
1603 	 * If no output was produced print a single 0.
1604 	 */
1605 	if (len == 0)
1606 		len = snprintf(buf, buf_size, "%d", 0);
1607 
1608 	if (add_cr)
1609 		len += snprintf(buf + len, max(buf_size - len, 0), "\n");
1610 
1611 	return len;
1612 }
1613 
1614 #define INPUT_DEV_CAP_ATTR(ev, bm)					\
1615 static ssize_t input_dev_show_cap_##bm(struct device *dev,		\
1616 				       struct device_attribute *attr,	\
1617 				       char *buf)			\
1618 {									\
1619 	struct input_dev *input_dev = to_input_dev(dev);		\
1620 	int len = input_print_bitmap(buf, PAGE_SIZE,			\
1621 				     input_dev->bm##bit, ev##_MAX,	\
1622 				     true);				\
1623 	return min_t(int, len, PAGE_SIZE);				\
1624 }									\
1625 static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
1626 
1627 INPUT_DEV_CAP_ATTR(EV, ev);
1628 INPUT_DEV_CAP_ATTR(KEY, key);
1629 INPUT_DEV_CAP_ATTR(REL, rel);
1630 INPUT_DEV_CAP_ATTR(ABS, abs);
1631 INPUT_DEV_CAP_ATTR(MSC, msc);
1632 INPUT_DEV_CAP_ATTR(LED, led);
1633 INPUT_DEV_CAP_ATTR(SND, snd);
1634 INPUT_DEV_CAP_ATTR(FF, ff);
1635 INPUT_DEV_CAP_ATTR(SW, sw);
1636 
1637 static struct attribute *input_dev_caps_attrs[] = {
1638 	&dev_attr_ev.attr,
1639 	&dev_attr_key.attr,
1640 	&dev_attr_rel.attr,
1641 	&dev_attr_abs.attr,
1642 	&dev_attr_msc.attr,
1643 	&dev_attr_led.attr,
1644 	&dev_attr_snd.attr,
1645 	&dev_attr_ff.attr,
1646 	&dev_attr_sw.attr,
1647 	NULL
1648 };
1649 
1650 static const struct attribute_group input_dev_caps_attr_group = {
1651 	.name	= "capabilities",
1652 	.attrs	= input_dev_caps_attrs,
1653 };
1654 
1655 static const struct attribute_group *input_dev_attr_groups[] = {
1656 	&input_dev_attr_group,
1657 	&input_dev_id_attr_group,
1658 	&input_dev_caps_attr_group,
1659 	&input_poller_attribute_group,
1660 	NULL
1661 };
1662 
input_dev_release(struct device * device)1663 static void input_dev_release(struct device *device)
1664 {
1665 	struct input_dev *dev = to_input_dev(device);
1666 
1667 	input_ff_destroy(dev);
1668 	input_mt_destroy_slots(dev);
1669 	kfree(dev->poller);
1670 	kfree(dev->absinfo);
1671 	kfree(dev->vals);
1672 	kfree(dev);
1673 
1674 	module_put(THIS_MODULE);
1675 }
1676 
1677 /*
1678  * Input uevent interface - loading event handlers based on
1679  * device bitfields.
1680  */
input_add_uevent_bm_var(struct kobj_uevent_env * env,const char * name,const unsigned long * bitmap,int max)1681 static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
1682 				   const char *name, const unsigned long *bitmap, int max)
1683 {
1684 	int len;
1685 
1686 	if (add_uevent_var(env, "%s", name))
1687 		return -ENOMEM;
1688 
1689 	len = input_print_bitmap(&env->buf[env->buflen - 1],
1690 				 sizeof(env->buf) - env->buflen,
1691 				 bitmap, max, false);
1692 	if (len >= (sizeof(env->buf) - env->buflen))
1693 		return -ENOMEM;
1694 
1695 	env->buflen += len;
1696 	return 0;
1697 }
1698 
1699 /*
1700  * This is a pretty gross hack. When building uevent data the driver core
1701  * may try adding more environment variables to kobj_uevent_env without
1702  * telling us, so we have no idea how much of the buffer we can use to
1703  * avoid overflows/-ENOMEM elsewhere. To work around this let's artificially
1704  * reduce amount of memory we will use for the modalias environment variable.
1705  *
1706  * The potential additions are:
1707  *
1708  * SEQNUM=18446744073709551615 - (%llu - 28 bytes)
1709  * HOME=/ (6 bytes)
1710  * PATH=/sbin:/bin:/usr/sbin:/usr/bin (34 bytes)
1711  *
1712  * 68 bytes total. Allow extra buffer - 96 bytes
1713  */
1714 #define UEVENT_ENV_EXTRA_LEN	96
1715 
input_add_uevent_modalias_var(struct kobj_uevent_env * env,const struct input_dev * dev)1716 static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
1717 					 const struct input_dev *dev)
1718 {
1719 	int len;
1720 
1721 	if (add_uevent_var(env, "MODALIAS="))
1722 		return -ENOMEM;
1723 
1724 	len = input_print_modalias(&env->buf[env->buflen - 1],
1725 				   (int)sizeof(env->buf) - env->buflen -
1726 					UEVENT_ENV_EXTRA_LEN,
1727 				   dev);
1728 	if (len >= ((int)sizeof(env->buf) - env->buflen -
1729 					UEVENT_ENV_EXTRA_LEN))
1730 		return -ENOMEM;
1731 
1732 	env->buflen += len;
1733 	return 0;
1734 }
1735 
1736 #define INPUT_ADD_HOTPLUG_VAR(fmt, val...)				\
1737 	do {								\
1738 		int err = add_uevent_var(env, fmt, val);		\
1739 		if (err)						\
1740 			return err;					\
1741 	} while (0)
1742 
1743 #define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max)				\
1744 	do {								\
1745 		int err = input_add_uevent_bm_var(env, name, bm, max);	\
1746 		if (err)						\
1747 			return err;					\
1748 	} while (0)
1749 
1750 #define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev)				\
1751 	do {								\
1752 		int err = input_add_uevent_modalias_var(env, dev);	\
1753 		if (err)						\
1754 			return err;					\
1755 	} while (0)
1756 
input_dev_uevent(const struct device * device,struct kobj_uevent_env * env)1757 static int input_dev_uevent(const struct device *device, struct kobj_uevent_env *env)
1758 {
1759 	const struct input_dev *dev = to_input_dev(device);
1760 
1761 	INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
1762 				dev->id.bustype, dev->id.vendor,
1763 				dev->id.product, dev->id.version);
1764 	if (dev->name)
1765 		INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
1766 	if (dev->phys)
1767 		INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
1768 	if (dev->uniq)
1769 		INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);
1770 
1771 	INPUT_ADD_HOTPLUG_BM_VAR("PROP=", dev->propbit, INPUT_PROP_MAX);
1772 
1773 	INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
1774 	if (test_bit(EV_KEY, dev->evbit))
1775 		INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
1776 	if (test_bit(EV_REL, dev->evbit))
1777 		INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
1778 	if (test_bit(EV_ABS, dev->evbit))
1779 		INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
1780 	if (test_bit(EV_MSC, dev->evbit))
1781 		INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
1782 	if (test_bit(EV_LED, dev->evbit))
1783 		INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
1784 	if (test_bit(EV_SND, dev->evbit))
1785 		INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
1786 	if (test_bit(EV_FF, dev->evbit))
1787 		INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
1788 	if (test_bit(EV_SW, dev->evbit))
1789 		INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
1790 
1791 	INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
1792 
1793 	return 0;
1794 }
1795 
1796 #define INPUT_DO_TOGGLE(dev, type, bits, on)				\
1797 	do {								\
1798 		int i;							\
1799 		bool active;						\
1800 									\
1801 		if (!test_bit(EV_##type, dev->evbit))			\
1802 			break;						\
1803 									\
1804 		for_each_set_bit(i, dev->bits##bit, type##_CNT) {	\
1805 			active = test_bit(i, dev->bits);		\
1806 			if (!active && !on)				\
1807 				continue;				\
1808 									\
1809 			dev->event(dev, EV_##type, i, on ? active : 0);	\
1810 		}							\
1811 	} while (0)
1812 
input_dev_toggle(struct input_dev * dev,bool activate)1813 static void input_dev_toggle(struct input_dev *dev, bool activate)
1814 {
1815 	if (!dev->event)
1816 		return;
1817 
1818 	INPUT_DO_TOGGLE(dev, LED, led, activate);
1819 	INPUT_DO_TOGGLE(dev, SND, snd, activate);
1820 
1821 	if (activate && test_bit(EV_REP, dev->evbit)) {
1822 		dev->event(dev, EV_REP, REP_PERIOD, dev->rep[REP_PERIOD]);
1823 		dev->event(dev, EV_REP, REP_DELAY, dev->rep[REP_DELAY]);
1824 	}
1825 }
1826 
1827 /**
1828  * input_reset_device() - reset/restore the state of input device
1829  * @dev: input device whose state needs to be reset
1830  *
1831  * This function tries to reset the state of an opened input device and
1832  * bring internal state and state if the hardware in sync with each other.
1833  * We mark all keys as released, restore LED state, repeat rate, etc.
1834  */
input_reset_device(struct input_dev * dev)1835 void input_reset_device(struct input_dev *dev)
1836 {
1837 	unsigned long flags;
1838 
1839 	mutex_lock(&dev->mutex);
1840 	spin_lock_irqsave(&dev->event_lock, flags);
1841 
1842 	input_dev_toggle(dev, true);
1843 	if (input_dev_release_keys(dev))
1844 		input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
1845 
1846 	spin_unlock_irqrestore(&dev->event_lock, flags);
1847 	mutex_unlock(&dev->mutex);
1848 }
1849 EXPORT_SYMBOL(input_reset_device);
1850 
input_inhibit_device(struct input_dev * dev)1851 static int input_inhibit_device(struct input_dev *dev)
1852 {
1853 	mutex_lock(&dev->mutex);
1854 
1855 	if (dev->inhibited)
1856 		goto out;
1857 
1858 	if (dev->users) {
1859 		if (dev->close)
1860 			dev->close(dev);
1861 		if (dev->poller)
1862 			input_dev_poller_stop(dev->poller);
1863 	}
1864 
1865 	spin_lock_irq(&dev->event_lock);
1866 	input_mt_release_slots(dev);
1867 	input_dev_release_keys(dev);
1868 	input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
1869 	input_dev_toggle(dev, false);
1870 	spin_unlock_irq(&dev->event_lock);
1871 
1872 	dev->inhibited = true;
1873 
1874 out:
1875 	mutex_unlock(&dev->mutex);
1876 	return 0;
1877 }
1878 
input_uninhibit_device(struct input_dev * dev)1879 static int input_uninhibit_device(struct input_dev *dev)
1880 {
1881 	int ret = 0;
1882 
1883 	mutex_lock(&dev->mutex);
1884 
1885 	if (!dev->inhibited)
1886 		goto out;
1887 
1888 	if (dev->users) {
1889 		if (dev->open) {
1890 			ret = dev->open(dev);
1891 			if (ret)
1892 				goto out;
1893 		}
1894 		if (dev->poller)
1895 			input_dev_poller_start(dev->poller);
1896 	}
1897 
1898 	dev->inhibited = false;
1899 	spin_lock_irq(&dev->event_lock);
1900 	input_dev_toggle(dev, true);
1901 	spin_unlock_irq(&dev->event_lock);
1902 
1903 out:
1904 	mutex_unlock(&dev->mutex);
1905 	return ret;
1906 }
1907 
input_dev_suspend(struct device * dev)1908 static int input_dev_suspend(struct device *dev)
1909 {
1910 	struct input_dev *input_dev = to_input_dev(dev);
1911 
1912 	spin_lock_irq(&input_dev->event_lock);
1913 
1914 	/*
1915 	 * Keys that are pressed now are unlikely to be
1916 	 * still pressed when we resume.
1917 	 */
1918 	if (input_dev_release_keys(input_dev))
1919 		input_handle_event(input_dev, EV_SYN, SYN_REPORT, 1);
1920 
1921 	/* Turn off LEDs and sounds, if any are active. */
1922 	input_dev_toggle(input_dev, false);
1923 
1924 	spin_unlock_irq(&input_dev->event_lock);
1925 
1926 	return 0;
1927 }
1928 
input_dev_resume(struct device * dev)1929 static int input_dev_resume(struct device *dev)
1930 {
1931 	struct input_dev *input_dev = to_input_dev(dev);
1932 
1933 	spin_lock_irq(&input_dev->event_lock);
1934 
1935 	/* Restore state of LEDs and sounds, if any were active. */
1936 	input_dev_toggle(input_dev, true);
1937 
1938 	spin_unlock_irq(&input_dev->event_lock);
1939 
1940 	return 0;
1941 }
1942 
input_dev_freeze(struct device * dev)1943 static int input_dev_freeze(struct device *dev)
1944 {
1945 	struct input_dev *input_dev = to_input_dev(dev);
1946 
1947 	spin_lock_irq(&input_dev->event_lock);
1948 
1949 	/*
1950 	 * Keys that are pressed now are unlikely to be
1951 	 * still pressed when we resume.
1952 	 */
1953 	if (input_dev_release_keys(input_dev))
1954 		input_handle_event(input_dev, EV_SYN, SYN_REPORT, 1);
1955 
1956 	spin_unlock_irq(&input_dev->event_lock);
1957 
1958 	return 0;
1959 }
1960 
input_dev_poweroff(struct device * dev)1961 static int input_dev_poweroff(struct device *dev)
1962 {
1963 	struct input_dev *input_dev = to_input_dev(dev);
1964 
1965 	spin_lock_irq(&input_dev->event_lock);
1966 
1967 	/* Turn off LEDs and sounds, if any are active. */
1968 	input_dev_toggle(input_dev, false);
1969 
1970 	spin_unlock_irq(&input_dev->event_lock);
1971 
1972 	return 0;
1973 }
1974 
1975 static const struct dev_pm_ops input_dev_pm_ops = {
1976 	.suspend	= input_dev_suspend,
1977 	.resume		= input_dev_resume,
1978 	.freeze		= input_dev_freeze,
1979 	.poweroff	= input_dev_poweroff,
1980 	.restore	= input_dev_resume,
1981 };
1982 
1983 static const struct device_type input_dev_type = {
1984 	.groups		= input_dev_attr_groups,
1985 	.release	= input_dev_release,
1986 	.uevent		= input_dev_uevent,
1987 	.pm		= pm_sleep_ptr(&input_dev_pm_ops),
1988 };
1989 
input_devnode(const struct device * dev,umode_t * mode)1990 static char *input_devnode(const struct device *dev, umode_t *mode)
1991 {
1992 	return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
1993 }
1994 
1995 struct class input_class = {
1996 	.name		= "input",
1997 	.devnode	= input_devnode,
1998 };
1999 EXPORT_SYMBOL_GPL(input_class);
2000 
2001 /**
2002  * input_allocate_device - allocate memory for new input device
2003  *
2004  * Returns prepared struct input_dev or %NULL.
2005  *
2006  * NOTE: Use input_free_device() to free devices that have not been
2007  * registered; input_unregister_device() should be used for already
2008  * registered devices.
2009  */
input_allocate_device(void)2010 struct input_dev *input_allocate_device(void)
2011 {
2012 	static atomic_t input_no = ATOMIC_INIT(-1);
2013 	struct input_dev *dev;
2014 
2015 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2016 	if (dev) {
2017 		dev->dev.type = &input_dev_type;
2018 		dev->dev.class = &input_class;
2019 		device_initialize(&dev->dev);
2020 		mutex_init(&dev->mutex);
2021 		spin_lock_init(&dev->event_lock);
2022 		timer_setup(&dev->timer, NULL, 0);
2023 		INIT_LIST_HEAD(&dev->h_list);
2024 		INIT_LIST_HEAD(&dev->node);
2025 
2026 		dev_set_name(&dev->dev, "input%lu",
2027 			     (unsigned long)atomic_inc_return(&input_no));
2028 
2029 		__module_get(THIS_MODULE);
2030 	}
2031 
2032 	return dev;
2033 }
2034 EXPORT_SYMBOL(input_allocate_device);
2035 
2036 struct input_devres {
2037 	struct input_dev *input;
2038 };
2039 
devm_input_device_match(struct device * dev,void * res,void * data)2040 static int devm_input_device_match(struct device *dev, void *res, void *data)
2041 {
2042 	struct input_devres *devres = res;
2043 
2044 	return devres->input == data;
2045 }
2046 
devm_input_device_release(struct device * dev,void * res)2047 static void devm_input_device_release(struct device *dev, void *res)
2048 {
2049 	struct input_devres *devres = res;
2050 	struct input_dev *input = devres->input;
2051 
2052 	dev_dbg(dev, "%s: dropping reference to %s\n",
2053 		__func__, dev_name(&input->dev));
2054 	input_put_device(input);
2055 }
2056 
2057 /**
2058  * devm_input_allocate_device - allocate managed input device
2059  * @dev: device owning the input device being created
2060  *
2061  * Returns prepared struct input_dev or %NULL.
2062  *
2063  * Managed input devices do not need to be explicitly unregistered or
2064  * freed as it will be done automatically when owner device unbinds from
2065  * its driver (or binding fails). Once managed input device is allocated,
2066  * it is ready to be set up and registered in the same fashion as regular
2067  * input device. There are no special devm_input_device_[un]register()
2068  * variants, regular ones work with both managed and unmanaged devices,
2069  * should you need them. In most cases however, managed input device need
2070  * not be explicitly unregistered or freed.
2071  *
2072  * NOTE: the owner device is set up as parent of input device and users
2073  * should not override it.
2074  */
devm_input_allocate_device(struct device * dev)2075 struct input_dev *devm_input_allocate_device(struct device *dev)
2076 {
2077 	struct input_dev *input;
2078 	struct input_devres *devres;
2079 
2080 	devres = devres_alloc(devm_input_device_release,
2081 			      sizeof(*devres), GFP_KERNEL);
2082 	if (!devres)
2083 		return NULL;
2084 
2085 	input = input_allocate_device();
2086 	if (!input) {
2087 		devres_free(devres);
2088 		return NULL;
2089 	}
2090 
2091 	input->dev.parent = dev;
2092 	input->devres_managed = true;
2093 
2094 	devres->input = input;
2095 	devres_add(dev, devres);
2096 
2097 	return input;
2098 }
2099 EXPORT_SYMBOL(devm_input_allocate_device);
2100 
2101 /**
2102  * input_free_device - free memory occupied by input_dev structure
2103  * @dev: input device to free
2104  *
2105  * This function should only be used if input_register_device()
2106  * was not called yet or if it failed. Once device was registered
2107  * use input_unregister_device() and memory will be freed once last
2108  * reference to the device is dropped.
2109  *
2110  * Device should be allocated by input_allocate_device().
2111  *
2112  * NOTE: If there are references to the input device then memory
2113  * will not be freed until last reference is dropped.
2114  */
input_free_device(struct input_dev * dev)2115 void input_free_device(struct input_dev *dev)
2116 {
2117 	if (dev) {
2118 		if (dev->devres_managed)
2119 			WARN_ON(devres_destroy(dev->dev.parent,
2120 						devm_input_device_release,
2121 						devm_input_device_match,
2122 						dev));
2123 		input_put_device(dev);
2124 	}
2125 }
2126 EXPORT_SYMBOL(input_free_device);
2127 
2128 /**
2129  * input_set_timestamp - set timestamp for input events
2130  * @dev: input device to set timestamp for
2131  * @timestamp: the time at which the event has occurred
2132  *   in CLOCK_MONOTONIC
2133  *
2134  * This function is intended to provide to the input system a more
2135  * accurate time of when an event actually occurred. The driver should
2136  * call this function as soon as a timestamp is acquired ensuring
2137  * clock conversions in input_set_timestamp are done correctly.
2138  *
2139  * The system entering suspend state between timestamp acquisition and
2140  * calling input_set_timestamp can result in inaccurate conversions.
2141  */
input_set_timestamp(struct input_dev * dev,ktime_t timestamp)2142 void input_set_timestamp(struct input_dev *dev, ktime_t timestamp)
2143 {
2144 	dev->timestamp[INPUT_CLK_MONO] = timestamp;
2145 	dev->timestamp[INPUT_CLK_REAL] = ktime_mono_to_real(timestamp);
2146 	dev->timestamp[INPUT_CLK_BOOT] = ktime_mono_to_any(timestamp,
2147 							   TK_OFFS_BOOT);
2148 }
2149 EXPORT_SYMBOL(input_set_timestamp);
2150 
2151 /**
2152  * input_get_timestamp - get timestamp for input events
2153  * @dev: input device to get timestamp from
2154  *
2155  * A valid timestamp is a timestamp of non-zero value.
2156  */
input_get_timestamp(struct input_dev * dev)2157 ktime_t *input_get_timestamp(struct input_dev *dev)
2158 {
2159 	const ktime_t invalid_timestamp = ktime_set(0, 0);
2160 
2161 	if (!ktime_compare(dev->timestamp[INPUT_CLK_MONO], invalid_timestamp))
2162 		input_set_timestamp(dev, ktime_get());
2163 
2164 	return dev->timestamp;
2165 }
2166 EXPORT_SYMBOL(input_get_timestamp);
2167 
2168 /**
2169  * input_set_capability - mark device as capable of a certain event
2170  * @dev: device that is capable of emitting or accepting event
2171  * @type: type of the event (EV_KEY, EV_REL, etc...)
2172  * @code: event code
2173  *
2174  * In addition to setting up corresponding bit in appropriate capability
2175  * bitmap the function also adjusts dev->evbit.
2176  */
input_set_capability(struct input_dev * dev,unsigned int type,unsigned int code)2177 void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
2178 {
2179 	if (type < EV_CNT && input_max_code[type] &&
2180 	    code > input_max_code[type]) {
2181 		pr_err("%s: invalid code %u for type %u\n", __func__, code,
2182 		       type);
2183 		dump_stack();
2184 		return;
2185 	}
2186 
2187 	switch (type) {
2188 	case EV_KEY:
2189 		__set_bit(code, dev->keybit);
2190 		break;
2191 
2192 	case EV_REL:
2193 		__set_bit(code, dev->relbit);
2194 		break;
2195 
2196 	case EV_ABS:
2197 		input_alloc_absinfo(dev);
2198 		__set_bit(code, dev->absbit);
2199 		break;
2200 
2201 	case EV_MSC:
2202 		__set_bit(code, dev->mscbit);
2203 		break;
2204 
2205 	case EV_SW:
2206 		__set_bit(code, dev->swbit);
2207 		break;
2208 
2209 	case EV_LED:
2210 		__set_bit(code, dev->ledbit);
2211 		break;
2212 
2213 	case EV_SND:
2214 		__set_bit(code, dev->sndbit);
2215 		break;
2216 
2217 	case EV_FF:
2218 		__set_bit(code, dev->ffbit);
2219 		break;
2220 
2221 	case EV_PWR:
2222 		/* do nothing */
2223 		break;
2224 
2225 	default:
2226 		pr_err("%s: unknown type %u (code %u)\n", __func__, type, code);
2227 		dump_stack();
2228 		return;
2229 	}
2230 
2231 	__set_bit(type, dev->evbit);
2232 }
2233 EXPORT_SYMBOL(input_set_capability);
2234 
input_estimate_events_per_packet(struct input_dev * dev)2235 static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
2236 {
2237 	int mt_slots;
2238 	int i;
2239 	unsigned int events;
2240 
2241 	if (dev->mt) {
2242 		mt_slots = dev->mt->num_slots;
2243 	} else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
2244 		mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
2245 			   dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,
2246 		mt_slots = clamp(mt_slots, 2, 32);
2247 	} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
2248 		mt_slots = 2;
2249 	} else {
2250 		mt_slots = 0;
2251 	}
2252 
2253 	events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
2254 
2255 	if (test_bit(EV_ABS, dev->evbit))
2256 		for_each_set_bit(i, dev->absbit, ABS_CNT)
2257 			events += input_is_mt_axis(i) ? mt_slots : 1;
2258 
2259 	if (test_bit(EV_REL, dev->evbit))
2260 		events += bitmap_weight(dev->relbit, REL_CNT);
2261 
2262 	/* Make room for KEY and MSC events */
2263 	events += 7;
2264 
2265 	return events;
2266 }
2267 
2268 #define INPUT_CLEANSE_BITMASK(dev, type, bits)				\
2269 	do {								\
2270 		if (!test_bit(EV_##type, dev->evbit))			\
2271 			memset(dev->bits##bit, 0,			\
2272 				sizeof(dev->bits##bit));		\
2273 	} while (0)
2274 
input_cleanse_bitmasks(struct input_dev * dev)2275 static void input_cleanse_bitmasks(struct input_dev *dev)
2276 {
2277 	INPUT_CLEANSE_BITMASK(dev, KEY, key);
2278 	INPUT_CLEANSE_BITMASK(dev, REL, rel);
2279 	INPUT_CLEANSE_BITMASK(dev, ABS, abs);
2280 	INPUT_CLEANSE_BITMASK(dev, MSC, msc);
2281 	INPUT_CLEANSE_BITMASK(dev, LED, led);
2282 	INPUT_CLEANSE_BITMASK(dev, SND, snd);
2283 	INPUT_CLEANSE_BITMASK(dev, FF, ff);
2284 	INPUT_CLEANSE_BITMASK(dev, SW, sw);
2285 }
2286 
__input_unregister_device(struct input_dev * dev)2287 static void __input_unregister_device(struct input_dev *dev)
2288 {
2289 	struct input_handle *handle, *next;
2290 
2291 	input_disconnect_device(dev);
2292 
2293 	mutex_lock(&input_mutex);
2294 
2295 	list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
2296 		handle->handler->disconnect(handle);
2297 	WARN_ON(!list_empty(&dev->h_list));
2298 
2299 	del_timer_sync(&dev->timer);
2300 	list_del_init(&dev->node);
2301 
2302 	input_wakeup_procfs_readers();
2303 
2304 	mutex_unlock(&input_mutex);
2305 
2306 	device_del(&dev->dev);
2307 }
2308 
devm_input_device_unregister(struct device * dev,void * res)2309 static void devm_input_device_unregister(struct device *dev, void *res)
2310 {
2311 	struct input_devres *devres = res;
2312 	struct input_dev *input = devres->input;
2313 
2314 	dev_dbg(dev, "%s: unregistering device %s\n",
2315 		__func__, dev_name(&input->dev));
2316 	__input_unregister_device(input);
2317 }
2318 
2319 /*
2320  * Generate software autorepeat event. Note that we take
2321  * dev->event_lock here to avoid racing with input_event
2322  * which may cause keys get "stuck".
2323  */
input_repeat_key(struct timer_list * t)2324 static void input_repeat_key(struct timer_list *t)
2325 {
2326 	struct input_dev *dev = from_timer(dev, t, timer);
2327 	unsigned long flags;
2328 
2329 	spin_lock_irqsave(&dev->event_lock, flags);
2330 
2331 	if (!dev->inhibited &&
2332 	    test_bit(dev->repeat_key, dev->key) &&
2333 	    is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
2334 
2335 		input_set_timestamp(dev, ktime_get());
2336 		input_handle_event(dev, EV_KEY, dev->repeat_key, 2);
2337 		input_handle_event(dev, EV_SYN, SYN_REPORT, 1);
2338 
2339 		if (dev->rep[REP_PERIOD])
2340 			mod_timer(&dev->timer, jiffies +
2341 					msecs_to_jiffies(dev->rep[REP_PERIOD]));
2342 	}
2343 
2344 	spin_unlock_irqrestore(&dev->event_lock, flags);
2345 }
2346 
2347 /**
2348  * input_enable_softrepeat - enable software autorepeat
2349  * @dev: input device
2350  * @delay: repeat delay
2351  * @period: repeat period
2352  *
2353  * Enable software autorepeat on the input device.
2354  */
input_enable_softrepeat(struct input_dev * dev,int delay,int period)2355 void input_enable_softrepeat(struct input_dev *dev, int delay, int period)
2356 {
2357 	dev->timer.function = input_repeat_key;
2358 	dev->rep[REP_DELAY] = delay;
2359 	dev->rep[REP_PERIOD] = period;
2360 }
2361 EXPORT_SYMBOL(input_enable_softrepeat);
2362 
input_device_enabled(struct input_dev * dev)2363 bool input_device_enabled(struct input_dev *dev)
2364 {
2365 	lockdep_assert_held(&dev->mutex);
2366 
2367 	return !dev->inhibited && dev->users > 0;
2368 }
2369 EXPORT_SYMBOL_GPL(input_device_enabled);
2370 
2371 /**
2372  * input_register_device - register device with input core
2373  * @dev: device to be registered
2374  *
2375  * This function registers device with input core. The device must be
2376  * allocated with input_allocate_device() and all it's capabilities
2377  * set up before registering.
2378  * If function fails the device must be freed with input_free_device().
2379  * Once device has been successfully registered it can be unregistered
2380  * with input_unregister_device(); input_free_device() should not be
2381  * called in this case.
2382  *
2383  * Note that this function is also used to register managed input devices
2384  * (ones allocated with devm_input_allocate_device()). Such managed input
2385  * devices need not be explicitly unregistered or freed, their tear down
2386  * is controlled by the devres infrastructure. It is also worth noting
2387  * that tear down of managed input devices is internally a 2-step process:
2388  * registered managed input device is first unregistered, but stays in
2389  * memory and can still handle input_event() calls (although events will
2390  * not be delivered anywhere). The freeing of managed input device will
2391  * happen later, when devres stack is unwound to the point where device
2392  * allocation was made.
2393  */
input_register_device(struct input_dev * dev)2394 int input_register_device(struct input_dev *dev)
2395 {
2396 	struct input_devres *devres = NULL;
2397 	struct input_handler *handler;
2398 	unsigned int packet_size;
2399 	const char *path;
2400 	int error;
2401 
2402 	if (test_bit(EV_ABS, dev->evbit) && !dev->absinfo) {
2403 		dev_err(&dev->dev,
2404 			"Absolute device without dev->absinfo, refusing to register\n");
2405 		return -EINVAL;
2406 	}
2407 
2408 	if (dev->devres_managed) {
2409 		devres = devres_alloc(devm_input_device_unregister,
2410 				      sizeof(*devres), GFP_KERNEL);
2411 		if (!devres)
2412 			return -ENOMEM;
2413 
2414 		devres->input = dev;
2415 	}
2416 
2417 	/* Every input device generates EV_SYN/SYN_REPORT events. */
2418 	__set_bit(EV_SYN, dev->evbit);
2419 
2420 	/* KEY_RESERVED is not supposed to be transmitted to userspace. */
2421 	__clear_bit(KEY_RESERVED, dev->keybit);
2422 
2423 	/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
2424 	input_cleanse_bitmasks(dev);
2425 
2426 	packet_size = input_estimate_events_per_packet(dev);
2427 	if (dev->hint_events_per_packet < packet_size)
2428 		dev->hint_events_per_packet = packet_size;
2429 
2430 	dev->max_vals = dev->hint_events_per_packet + 2;
2431 	dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
2432 	if (!dev->vals) {
2433 		error = -ENOMEM;
2434 		goto err_devres_free;
2435 	}
2436 
2437 	/*
2438 	 * If delay and period are pre-set by the driver, then autorepeating
2439 	 * is handled by the driver itself and we don't do it in input.c.
2440 	 */
2441 	if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD])
2442 		input_enable_softrepeat(dev, 250, 33);
2443 
2444 	if (!dev->getkeycode)
2445 		dev->getkeycode = input_default_getkeycode;
2446 
2447 	if (!dev->setkeycode)
2448 		dev->setkeycode = input_default_setkeycode;
2449 
2450 	if (dev->poller)
2451 		input_dev_poller_finalize(dev->poller);
2452 
2453 	error = device_add(&dev->dev);
2454 	if (error)
2455 		goto err_free_vals;
2456 
2457 	path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
2458 	pr_info("%s as %s\n",
2459 		dev->name ? dev->name : "Unspecified device",
2460 		path ? path : "N/A");
2461 	kfree(path);
2462 
2463 	error = mutex_lock_interruptible(&input_mutex);
2464 	if (error)
2465 		goto err_device_del;
2466 
2467 	list_add_tail(&dev->node, &input_dev_list);
2468 
2469 	list_for_each_entry(handler, &input_handler_list, node)
2470 		input_attach_handler(dev, handler);
2471 
2472 	input_wakeup_procfs_readers();
2473 
2474 	mutex_unlock(&input_mutex);
2475 
2476 	if (dev->devres_managed) {
2477 		dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
2478 			__func__, dev_name(&dev->dev));
2479 		devres_add(dev->dev.parent, devres);
2480 	}
2481 	return 0;
2482 
2483 err_device_del:
2484 	device_del(&dev->dev);
2485 err_free_vals:
2486 	kfree(dev->vals);
2487 	dev->vals = NULL;
2488 err_devres_free:
2489 	devres_free(devres);
2490 	return error;
2491 }
2492 EXPORT_SYMBOL(input_register_device);
2493 
2494 /**
2495  * input_unregister_device - unregister previously registered device
2496  * @dev: device to be unregistered
2497  *
2498  * This function unregisters an input device. Once device is unregistered
2499  * the caller should not try to access it as it may get freed at any moment.
2500  */
input_unregister_device(struct input_dev * dev)2501 void input_unregister_device(struct input_dev *dev)
2502 {
2503 	if (dev->devres_managed) {
2504 		WARN_ON(devres_destroy(dev->dev.parent,
2505 					devm_input_device_unregister,
2506 					devm_input_device_match,
2507 					dev));
2508 		__input_unregister_device(dev);
2509 		/*
2510 		 * We do not do input_put_device() here because it will be done
2511 		 * when 2nd devres fires up.
2512 		 */
2513 	} else {
2514 		__input_unregister_device(dev);
2515 		input_put_device(dev);
2516 	}
2517 }
2518 EXPORT_SYMBOL(input_unregister_device);
2519 
2520 /**
2521  * input_register_handler - register a new input handler
2522  * @handler: handler to be registered
2523  *
2524  * This function registers a new input handler (interface) for input
2525  * devices in the system and attaches it to all input devices that
2526  * are compatible with the handler.
2527  */
input_register_handler(struct input_handler * handler)2528 int input_register_handler(struct input_handler *handler)
2529 {
2530 	struct input_dev *dev;
2531 	int error;
2532 
2533 	error = mutex_lock_interruptible(&input_mutex);
2534 	if (error)
2535 		return error;
2536 
2537 	INIT_LIST_HEAD(&handler->h_list);
2538 
2539 	list_add_tail(&handler->node, &input_handler_list);
2540 
2541 	list_for_each_entry(dev, &input_dev_list, node)
2542 		input_attach_handler(dev, handler);
2543 
2544 	input_wakeup_procfs_readers();
2545 
2546 	mutex_unlock(&input_mutex);
2547 	return 0;
2548 }
2549 EXPORT_SYMBOL(input_register_handler);
2550 
2551 /**
2552  * input_unregister_handler - unregisters an input handler
2553  * @handler: handler to be unregistered
2554  *
2555  * This function disconnects a handler from its input devices and
2556  * removes it from lists of known handlers.
2557  */
input_unregister_handler(struct input_handler * handler)2558 void input_unregister_handler(struct input_handler *handler)
2559 {
2560 	struct input_handle *handle, *next;
2561 
2562 	mutex_lock(&input_mutex);
2563 
2564 	list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
2565 		handler->disconnect(handle);
2566 	WARN_ON(!list_empty(&handler->h_list));
2567 
2568 	list_del_init(&handler->node);
2569 
2570 	input_wakeup_procfs_readers();
2571 
2572 	mutex_unlock(&input_mutex);
2573 }
2574 EXPORT_SYMBOL(input_unregister_handler);
2575 
2576 /**
2577  * input_handler_for_each_handle - handle iterator
2578  * @handler: input handler to iterate
2579  * @data: data for the callback
2580  * @fn: function to be called for each handle
2581  *
2582  * Iterate over @bus's list of devices, and call @fn for each, passing
2583  * it @data and stop when @fn returns a non-zero value. The function is
2584  * using RCU to traverse the list and therefore may be using in atomic
2585  * contexts. The @fn callback is invoked from RCU critical section and
2586  * thus must not sleep.
2587  */
input_handler_for_each_handle(struct input_handler * handler,void * data,int (* fn)(struct input_handle *,void *))2588 int input_handler_for_each_handle(struct input_handler *handler, void *data,
2589 				  int (*fn)(struct input_handle *, void *))
2590 {
2591 	struct input_handle *handle;
2592 	int retval = 0;
2593 
2594 	rcu_read_lock();
2595 
2596 	list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
2597 		retval = fn(handle, data);
2598 		if (retval)
2599 			break;
2600 	}
2601 
2602 	rcu_read_unlock();
2603 
2604 	return retval;
2605 }
2606 EXPORT_SYMBOL(input_handler_for_each_handle);
2607 
2608 /**
2609  * input_register_handle - register a new input handle
2610  * @handle: handle to register
2611  *
2612  * This function puts a new input handle onto device's
2613  * and handler's lists so that events can flow through
2614  * it once it is opened using input_open_device().
2615  *
2616  * This function is supposed to be called from handler's
2617  * connect() method.
2618  */
input_register_handle(struct input_handle * handle)2619 int input_register_handle(struct input_handle *handle)
2620 {
2621 	struct input_handler *handler = handle->handler;
2622 	struct input_dev *dev = handle->dev;
2623 	int error;
2624 
2625 	/*
2626 	 * We take dev->mutex here to prevent race with
2627 	 * input_release_device().
2628 	 */
2629 	error = mutex_lock_interruptible(&dev->mutex);
2630 	if (error)
2631 		return error;
2632 
2633 	/*
2634 	 * Filters go to the head of the list, normal handlers
2635 	 * to the tail.
2636 	 */
2637 	if (handler->filter)
2638 		list_add_rcu(&handle->d_node, &dev->h_list);
2639 	else
2640 		list_add_tail_rcu(&handle->d_node, &dev->h_list);
2641 
2642 	mutex_unlock(&dev->mutex);
2643 
2644 	/*
2645 	 * Since we are supposed to be called from ->connect()
2646 	 * which is mutually exclusive with ->disconnect()
2647 	 * we can't be racing with input_unregister_handle()
2648 	 * and so separate lock is not needed here.
2649 	 */
2650 	list_add_tail_rcu(&handle->h_node, &handler->h_list);
2651 
2652 	if (handler->start)
2653 		handler->start(handle);
2654 
2655 	return 0;
2656 }
2657 EXPORT_SYMBOL(input_register_handle);
2658 
2659 /**
2660  * input_unregister_handle - unregister an input handle
2661  * @handle: handle to unregister
2662  *
2663  * This function removes input handle from device's
2664  * and handler's lists.
2665  *
2666  * This function is supposed to be called from handler's
2667  * disconnect() method.
2668  */
input_unregister_handle(struct input_handle * handle)2669 void input_unregister_handle(struct input_handle *handle)
2670 {
2671 	struct input_dev *dev = handle->dev;
2672 
2673 	list_del_rcu(&handle->h_node);
2674 
2675 	/*
2676 	 * Take dev->mutex to prevent race with input_release_device().
2677 	 */
2678 	mutex_lock(&dev->mutex);
2679 	list_del_rcu(&handle->d_node);
2680 	mutex_unlock(&dev->mutex);
2681 
2682 	synchronize_rcu();
2683 }
2684 EXPORT_SYMBOL(input_unregister_handle);
2685 
2686 /**
2687  * input_get_new_minor - allocates a new input minor number
2688  * @legacy_base: beginning or the legacy range to be searched
2689  * @legacy_num: size of legacy range
2690  * @allow_dynamic: whether we can also take ID from the dynamic range
2691  *
2692  * This function allocates a new device minor for from input major namespace.
2693  * Caller can request legacy minor by specifying @legacy_base and @legacy_num
2694  * parameters and whether ID can be allocated from dynamic range if there are
2695  * no free IDs in legacy range.
2696  */
input_get_new_minor(int legacy_base,unsigned int legacy_num,bool allow_dynamic)2697 int input_get_new_minor(int legacy_base, unsigned int legacy_num,
2698 			bool allow_dynamic)
2699 {
2700 	/*
2701 	 * This function should be called from input handler's ->connect()
2702 	 * methods, which are serialized with input_mutex, so no additional
2703 	 * locking is needed here.
2704 	 */
2705 	if (legacy_base >= 0) {
2706 		int minor = ida_simple_get(&input_ida,
2707 					   legacy_base,
2708 					   legacy_base + legacy_num,
2709 					   GFP_KERNEL);
2710 		if (minor >= 0 || !allow_dynamic)
2711 			return minor;
2712 	}
2713 
2714 	return ida_simple_get(&input_ida,
2715 			      INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
2716 			      GFP_KERNEL);
2717 }
2718 EXPORT_SYMBOL(input_get_new_minor);
2719 
2720 /**
2721  * input_free_minor - release previously allocated minor
2722  * @minor: minor to be released
2723  *
2724  * This function releases previously allocated input minor so that it can be
2725  * reused later.
2726  */
input_free_minor(unsigned int minor)2727 void input_free_minor(unsigned int minor)
2728 {
2729 	ida_simple_remove(&input_ida, minor);
2730 }
2731 EXPORT_SYMBOL(input_free_minor);
2732 
input_init(void)2733 static int __init input_init(void)
2734 {
2735 	int err;
2736 
2737 	err = class_register(&input_class);
2738 	if (err) {
2739 		pr_err("unable to register input_dev class\n");
2740 		return err;
2741 	}
2742 
2743 	err = input_proc_init();
2744 	if (err)
2745 		goto fail1;
2746 
2747 	err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
2748 				     INPUT_MAX_CHAR_DEVICES, "input");
2749 	if (err) {
2750 		pr_err("unable to register char major %d", INPUT_MAJOR);
2751 		goto fail2;
2752 	}
2753 
2754 	return 0;
2755 
2756  fail2:	input_proc_exit();
2757  fail1:	class_unregister(&input_class);
2758 	return err;
2759 }
2760 
input_exit(void)2761 static void __exit input_exit(void)
2762 {
2763 	input_proc_exit();
2764 	unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
2765 				 INPUT_MAX_CHAR_DEVICES);
2766 	class_unregister(&input_class);
2767 }
2768 
2769 subsys_initcall(input_init);
2770 module_exit(input_exit);
2771