xref: /linux/drivers/input/mousedev.c (revision d524dac9279b6a41ffdf7ff7958c577f2e387db6)
1 /*
2  * Input driver to ExplorerPS/2 device driver module.
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  * Copyright (c) 2004      Dmitry Torokhov
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as published by
9  * the Free Software Foundation.
10  */
11 
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 
14 #define MOUSEDEV_MINOR_BASE	32
15 #define MOUSEDEV_MINORS		32
16 #define MOUSEDEV_MIX		31
17 
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/poll.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/input.h>
24 #include <linux/random.h>
25 #include <linux/major.h>
26 #include <linux/device.h>
27 #include <linux/kernel.h>
28 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
29 #include <linux/miscdevice.h>
30 #endif
31 
32 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
33 MODULE_DESCRIPTION("Mouse (ExplorerPS/2) device interfaces");
34 MODULE_LICENSE("GPL");
35 
36 #ifndef CONFIG_INPUT_MOUSEDEV_SCREEN_X
37 #define CONFIG_INPUT_MOUSEDEV_SCREEN_X	1024
38 #endif
39 #ifndef CONFIG_INPUT_MOUSEDEV_SCREEN_Y
40 #define CONFIG_INPUT_MOUSEDEV_SCREEN_Y	768
41 #endif
42 
43 static int xres = CONFIG_INPUT_MOUSEDEV_SCREEN_X;
44 module_param(xres, uint, 0644);
45 MODULE_PARM_DESC(xres, "Horizontal screen resolution");
46 
47 static int yres = CONFIG_INPUT_MOUSEDEV_SCREEN_Y;
48 module_param(yres, uint, 0644);
49 MODULE_PARM_DESC(yres, "Vertical screen resolution");
50 
51 static unsigned tap_time = 200;
52 module_param(tap_time, uint, 0644);
53 MODULE_PARM_DESC(tap_time, "Tap time for touchpads in absolute mode (msecs)");
54 
55 struct mousedev_hw_data {
56 	int dx, dy, dz;
57 	int x, y;
58 	int abs_event;
59 	unsigned long buttons;
60 };
61 
62 struct mousedev {
63 	int open;
64 	int minor;
65 	struct input_handle handle;
66 	wait_queue_head_t wait;
67 	struct list_head client_list;
68 	spinlock_t client_lock; /* protects client_list */
69 	struct mutex mutex;
70 	struct device dev;
71 	bool exist;
72 
73 	struct list_head mixdev_node;
74 	int mixdev_open;
75 
76 	struct mousedev_hw_data packet;
77 	unsigned int pkt_count;
78 	int old_x[4], old_y[4];
79 	int frac_dx, frac_dy;
80 	unsigned long touch;
81 };
82 
83 enum mousedev_emul {
84 	MOUSEDEV_EMUL_PS2,
85 	MOUSEDEV_EMUL_IMPS,
86 	MOUSEDEV_EMUL_EXPS
87 };
88 
89 struct mousedev_motion {
90 	int dx, dy, dz;
91 	unsigned long buttons;
92 };
93 
94 #define PACKET_QUEUE_LEN	16
95 struct mousedev_client {
96 	struct fasync_struct *fasync;
97 	struct mousedev *mousedev;
98 	struct list_head node;
99 
100 	struct mousedev_motion packets[PACKET_QUEUE_LEN];
101 	unsigned int head, tail;
102 	spinlock_t packet_lock;
103 	int pos_x, pos_y;
104 
105 	signed char ps2[6];
106 	unsigned char ready, buffer, bufsiz;
107 	unsigned char imexseq, impsseq;
108 	enum mousedev_emul mode;
109 	unsigned long last_buttons;
110 };
111 
112 #define MOUSEDEV_SEQ_LEN	6
113 
114 static unsigned char mousedev_imps_seq[] = { 0xf3, 200, 0xf3, 100, 0xf3, 80 };
115 static unsigned char mousedev_imex_seq[] = { 0xf3, 200, 0xf3, 200, 0xf3, 80 };
116 
117 static struct input_handler mousedev_handler;
118 
119 static struct mousedev *mousedev_table[MOUSEDEV_MINORS];
120 static DEFINE_MUTEX(mousedev_table_mutex);
121 static struct mousedev *mousedev_mix;
122 static LIST_HEAD(mousedev_mix_list);
123 
124 static void mixdev_open_devices(void);
125 static void mixdev_close_devices(void);
126 
127 #define fx(i)  (mousedev->old_x[(mousedev->pkt_count - (i)) & 03])
128 #define fy(i)  (mousedev->old_y[(mousedev->pkt_count - (i)) & 03])
129 
130 static void mousedev_touchpad_event(struct input_dev *dev,
131 				    struct mousedev *mousedev,
132 				    unsigned int code, int value)
133 {
134 	int size, tmp;
135 	enum { FRACTION_DENOM = 128 };
136 
137 	switch (code) {
138 
139 	case ABS_X:
140 
141 		fx(0) = value;
142 		if (mousedev->touch && mousedev->pkt_count >= 2) {
143 			size = input_abs_get_max(dev, ABS_X) -
144 					input_abs_get_min(dev, ABS_X);
145 			if (size == 0)
146 				size = 256 * 2;
147 
148 			tmp = ((value - fx(2)) * 256 * FRACTION_DENOM) / size;
149 			tmp += mousedev->frac_dx;
150 			mousedev->packet.dx = tmp / FRACTION_DENOM;
151 			mousedev->frac_dx =
152 				tmp - mousedev->packet.dx * FRACTION_DENOM;
153 		}
154 		break;
155 
156 	case ABS_Y:
157 		fy(0) = value;
158 		if (mousedev->touch && mousedev->pkt_count >= 2) {
159 			/* use X size for ABS_Y to keep the same scale */
160 			size = input_abs_get_max(dev, ABS_X) -
161 					input_abs_get_min(dev, ABS_X);
162 			if (size == 0)
163 				size = 256 * 2;
164 
165 			tmp = -((value - fy(2)) * 256 * FRACTION_DENOM) / size;
166 			tmp += mousedev->frac_dy;
167 			mousedev->packet.dy = tmp / FRACTION_DENOM;
168 			mousedev->frac_dy = tmp -
169 				mousedev->packet.dy * FRACTION_DENOM;
170 		}
171 		break;
172 	}
173 }
174 
175 static void mousedev_abs_event(struct input_dev *dev, struct mousedev *mousedev,
176 				unsigned int code, int value)
177 {
178 	int min, max, size;
179 
180 	switch (code) {
181 
182 	case ABS_X:
183 		min = input_abs_get_min(dev, ABS_X);
184 		max = input_abs_get_max(dev, ABS_X);
185 
186 		size = max - min;
187 		if (size == 0)
188 			size = xres ? : 1;
189 
190 		clamp(value, min, max);
191 
192 		mousedev->packet.x = ((value - min) * xres) / size;
193 		mousedev->packet.abs_event = 1;
194 		break;
195 
196 	case ABS_Y:
197 		min = input_abs_get_min(dev, ABS_Y);
198 		max = input_abs_get_max(dev, ABS_Y);
199 
200 		size = max - min;
201 		if (size == 0)
202 			size = yres ? : 1;
203 
204 		clamp(value, min, max);
205 
206 		mousedev->packet.y = yres - ((value - min) * yres) / size;
207 		mousedev->packet.abs_event = 1;
208 		break;
209 	}
210 }
211 
212 static void mousedev_rel_event(struct mousedev *mousedev,
213 				unsigned int code, int value)
214 {
215 	switch (code) {
216 	case REL_X:
217 		mousedev->packet.dx += value;
218 		break;
219 
220 	case REL_Y:
221 		mousedev->packet.dy -= value;
222 		break;
223 
224 	case REL_WHEEL:
225 		mousedev->packet.dz -= value;
226 		break;
227 	}
228 }
229 
230 static void mousedev_key_event(struct mousedev *mousedev,
231 				unsigned int code, int value)
232 {
233 	int index;
234 
235 	switch (code) {
236 
237 	case BTN_TOUCH:
238 	case BTN_0:
239 	case BTN_LEFT:		index = 0; break;
240 
241 	case BTN_STYLUS:
242 	case BTN_1:
243 	case BTN_RIGHT:		index = 1; break;
244 
245 	case BTN_2:
246 	case BTN_FORWARD:
247 	case BTN_STYLUS2:
248 	case BTN_MIDDLE:	index = 2; break;
249 
250 	case BTN_3:
251 	case BTN_BACK:
252 	case BTN_SIDE:		index = 3; break;
253 
254 	case BTN_4:
255 	case BTN_EXTRA:		index = 4; break;
256 
257 	default:		return;
258 	}
259 
260 	if (value) {
261 		set_bit(index, &mousedev->packet.buttons);
262 		set_bit(index, &mousedev_mix->packet.buttons);
263 	} else {
264 		clear_bit(index, &mousedev->packet.buttons);
265 		clear_bit(index, &mousedev_mix->packet.buttons);
266 	}
267 }
268 
269 static void mousedev_notify_readers(struct mousedev *mousedev,
270 				    struct mousedev_hw_data *packet)
271 {
272 	struct mousedev_client *client;
273 	struct mousedev_motion *p;
274 	unsigned int new_head;
275 	int wake_readers = 0;
276 
277 	rcu_read_lock();
278 	list_for_each_entry_rcu(client, &mousedev->client_list, node) {
279 
280 		/* Just acquire the lock, interrupts already disabled */
281 		spin_lock(&client->packet_lock);
282 
283 		p = &client->packets[client->head];
284 		if (client->ready && p->buttons != mousedev->packet.buttons) {
285 			new_head = (client->head + 1) % PACKET_QUEUE_LEN;
286 			if (new_head != client->tail) {
287 				p = &client->packets[client->head = new_head];
288 				memset(p, 0, sizeof(struct mousedev_motion));
289 			}
290 		}
291 
292 		if (packet->abs_event) {
293 			p->dx += packet->x - client->pos_x;
294 			p->dy += packet->y - client->pos_y;
295 			client->pos_x = packet->x;
296 			client->pos_y = packet->y;
297 		}
298 
299 		client->pos_x += packet->dx;
300 		client->pos_x = client->pos_x < 0 ?
301 			0 : (client->pos_x >= xres ? xres : client->pos_x);
302 		client->pos_y += packet->dy;
303 		client->pos_y = client->pos_y < 0 ?
304 			0 : (client->pos_y >= yres ? yres : client->pos_y);
305 
306 		p->dx += packet->dx;
307 		p->dy += packet->dy;
308 		p->dz += packet->dz;
309 		p->buttons = mousedev->packet.buttons;
310 
311 		if (p->dx || p->dy || p->dz ||
312 		    p->buttons != client->last_buttons)
313 			client->ready = 1;
314 
315 		spin_unlock(&client->packet_lock);
316 
317 		if (client->ready) {
318 			kill_fasync(&client->fasync, SIGIO, POLL_IN);
319 			wake_readers = 1;
320 		}
321 	}
322 	rcu_read_unlock();
323 
324 	if (wake_readers)
325 		wake_up_interruptible(&mousedev->wait);
326 }
327 
328 static void mousedev_touchpad_touch(struct mousedev *mousedev, int value)
329 {
330 	if (!value) {
331 		if (mousedev->touch &&
332 		    time_before(jiffies,
333 				mousedev->touch + msecs_to_jiffies(tap_time))) {
334 			/*
335 			 * Toggle left button to emulate tap.
336 			 * We rely on the fact that mousedev_mix always has 0
337 			 * motion packet so we won't mess current position.
338 			 */
339 			set_bit(0, &mousedev->packet.buttons);
340 			set_bit(0, &mousedev_mix->packet.buttons);
341 			mousedev_notify_readers(mousedev, &mousedev_mix->packet);
342 			mousedev_notify_readers(mousedev_mix,
343 						&mousedev_mix->packet);
344 			clear_bit(0, &mousedev->packet.buttons);
345 			clear_bit(0, &mousedev_mix->packet.buttons);
346 		}
347 		mousedev->touch = mousedev->pkt_count = 0;
348 		mousedev->frac_dx = 0;
349 		mousedev->frac_dy = 0;
350 
351 	} else if (!mousedev->touch)
352 		mousedev->touch = jiffies;
353 }
354 
355 static void mousedev_event(struct input_handle *handle,
356 			   unsigned int type, unsigned int code, int value)
357 {
358 	struct mousedev *mousedev = handle->private;
359 
360 	switch (type) {
361 
362 	case EV_ABS:
363 		/* Ignore joysticks */
364 		if (test_bit(BTN_TRIGGER, handle->dev->keybit))
365 			return;
366 
367 		if (test_bit(BTN_TOOL_FINGER, handle->dev->keybit))
368 			mousedev_touchpad_event(handle->dev,
369 						mousedev, code, value);
370 		else
371 			mousedev_abs_event(handle->dev, mousedev, code, value);
372 
373 		break;
374 
375 	case EV_REL:
376 		mousedev_rel_event(mousedev, code, value);
377 		break;
378 
379 	case EV_KEY:
380 		if (value != 2) {
381 			if (code == BTN_TOUCH &&
382 			    test_bit(BTN_TOOL_FINGER, handle->dev->keybit))
383 				mousedev_touchpad_touch(mousedev, value);
384 			else
385 				mousedev_key_event(mousedev, code, value);
386 		}
387 		break;
388 
389 	case EV_SYN:
390 		if (code == SYN_REPORT) {
391 			if (mousedev->touch) {
392 				mousedev->pkt_count++;
393 				/*
394 				 * Input system eats duplicate events,
395 				 * but we need all of them to do correct
396 				 * averaging so apply present one forward
397 				 */
398 				fx(0) = fx(1);
399 				fy(0) = fy(1);
400 			}
401 
402 			mousedev_notify_readers(mousedev, &mousedev->packet);
403 			mousedev_notify_readers(mousedev_mix, &mousedev->packet);
404 
405 			mousedev->packet.dx = mousedev->packet.dy =
406 				mousedev->packet.dz = 0;
407 			mousedev->packet.abs_event = 0;
408 		}
409 		break;
410 	}
411 }
412 
413 static int mousedev_fasync(int fd, struct file *file, int on)
414 {
415 	struct mousedev_client *client = file->private_data;
416 
417 	return fasync_helper(fd, file, on, &client->fasync);
418 }
419 
420 static void mousedev_free(struct device *dev)
421 {
422 	struct mousedev *mousedev = container_of(dev, struct mousedev, dev);
423 
424 	input_put_device(mousedev->handle.dev);
425 	kfree(mousedev);
426 }
427 
428 static int mousedev_open_device(struct mousedev *mousedev)
429 {
430 	int retval;
431 
432 	retval = mutex_lock_interruptible(&mousedev->mutex);
433 	if (retval)
434 		return retval;
435 
436 	if (mousedev->minor == MOUSEDEV_MIX)
437 		mixdev_open_devices();
438 	else if (!mousedev->exist)
439 		retval = -ENODEV;
440 	else if (!mousedev->open++) {
441 		retval = input_open_device(&mousedev->handle);
442 		if (retval)
443 			mousedev->open--;
444 	}
445 
446 	mutex_unlock(&mousedev->mutex);
447 	return retval;
448 }
449 
450 static void mousedev_close_device(struct mousedev *mousedev)
451 {
452 	mutex_lock(&mousedev->mutex);
453 
454 	if (mousedev->minor == MOUSEDEV_MIX)
455 		mixdev_close_devices();
456 	else if (mousedev->exist && !--mousedev->open)
457 		input_close_device(&mousedev->handle);
458 
459 	mutex_unlock(&mousedev->mutex);
460 }
461 
462 /*
463  * Open all available devices so they can all be multiplexed in one.
464  * stream. Note that this function is called with mousedev_mix->mutex
465  * held.
466  */
467 static void mixdev_open_devices(void)
468 {
469 	struct mousedev *mousedev;
470 
471 	if (mousedev_mix->open++)
472 		return;
473 
474 	list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
475 		if (!mousedev->mixdev_open) {
476 			if (mousedev_open_device(mousedev))
477 				continue;
478 
479 			mousedev->mixdev_open = 1;
480 		}
481 	}
482 }
483 
484 /*
485  * Close all devices that were opened as part of multiplexed
486  * device. Note that this function is called with mousedev_mix->mutex
487  * held.
488  */
489 static void mixdev_close_devices(void)
490 {
491 	struct mousedev *mousedev;
492 
493 	if (--mousedev_mix->open)
494 		return;
495 
496 	list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
497 		if (mousedev->mixdev_open) {
498 			mousedev->mixdev_open = 0;
499 			mousedev_close_device(mousedev);
500 		}
501 	}
502 }
503 
504 
505 static void mousedev_attach_client(struct mousedev *mousedev,
506 				   struct mousedev_client *client)
507 {
508 	spin_lock(&mousedev->client_lock);
509 	list_add_tail_rcu(&client->node, &mousedev->client_list);
510 	spin_unlock(&mousedev->client_lock);
511 	synchronize_rcu();
512 }
513 
514 static void mousedev_detach_client(struct mousedev *mousedev,
515 				   struct mousedev_client *client)
516 {
517 	spin_lock(&mousedev->client_lock);
518 	list_del_rcu(&client->node);
519 	spin_unlock(&mousedev->client_lock);
520 	synchronize_rcu();
521 }
522 
523 static int mousedev_release(struct inode *inode, struct file *file)
524 {
525 	struct mousedev_client *client = file->private_data;
526 	struct mousedev *mousedev = client->mousedev;
527 
528 	mousedev_detach_client(mousedev, client);
529 	kfree(client);
530 
531 	mousedev_close_device(mousedev);
532 	put_device(&mousedev->dev);
533 
534 	return 0;
535 }
536 
537 static int mousedev_open(struct inode *inode, struct file *file)
538 {
539 	struct mousedev_client *client;
540 	struct mousedev *mousedev;
541 	int error;
542 	int i;
543 
544 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
545 	if (imajor(inode) == MISC_MAJOR)
546 		i = MOUSEDEV_MIX;
547 	else
548 #endif
549 		i = iminor(inode) - MOUSEDEV_MINOR_BASE;
550 
551 	if (i >= MOUSEDEV_MINORS)
552 		return -ENODEV;
553 
554 	error = mutex_lock_interruptible(&mousedev_table_mutex);
555 	if (error) {
556 		return error;
557 	}
558 	mousedev = mousedev_table[i];
559 	if (mousedev)
560 		get_device(&mousedev->dev);
561 	mutex_unlock(&mousedev_table_mutex);
562 
563 	if (!mousedev) {
564 		return -ENODEV;
565 	}
566 
567 	client = kzalloc(sizeof(struct mousedev_client), GFP_KERNEL);
568 	if (!client) {
569 		error = -ENOMEM;
570 		goto err_put_mousedev;
571 	}
572 
573 	spin_lock_init(&client->packet_lock);
574 	client->pos_x = xres / 2;
575 	client->pos_y = yres / 2;
576 	client->mousedev = mousedev;
577 	mousedev_attach_client(mousedev, client);
578 
579 	error = mousedev_open_device(mousedev);
580 	if (error)
581 		goto err_free_client;
582 
583 	file->private_data = client;
584 	return 0;
585 
586  err_free_client:
587 	mousedev_detach_client(mousedev, client);
588 	kfree(client);
589  err_put_mousedev:
590 	put_device(&mousedev->dev);
591 	return error;
592 }
593 
594 static inline int mousedev_limit_delta(int delta, int limit)
595 {
596 	return delta > limit ? limit : (delta < -limit ? -limit : delta);
597 }
598 
599 static void mousedev_packet(struct mousedev_client *client,
600 			    signed char *ps2_data)
601 {
602 	struct mousedev_motion *p = &client->packets[client->tail];
603 
604 	ps2_data[0] = 0x08 |
605 		((p->dx < 0) << 4) | ((p->dy < 0) << 5) | (p->buttons & 0x07);
606 	ps2_data[1] = mousedev_limit_delta(p->dx, 127);
607 	ps2_data[2] = mousedev_limit_delta(p->dy, 127);
608 	p->dx -= ps2_data[1];
609 	p->dy -= ps2_data[2];
610 
611 	switch (client->mode) {
612 	case MOUSEDEV_EMUL_EXPS:
613 		ps2_data[3] = mousedev_limit_delta(p->dz, 7);
614 		p->dz -= ps2_data[3];
615 		ps2_data[3] = (ps2_data[3] & 0x0f) | ((p->buttons & 0x18) << 1);
616 		client->bufsiz = 4;
617 		break;
618 
619 	case MOUSEDEV_EMUL_IMPS:
620 		ps2_data[0] |=
621 			((p->buttons & 0x10) >> 3) | ((p->buttons & 0x08) >> 1);
622 		ps2_data[3] = mousedev_limit_delta(p->dz, 127);
623 		p->dz -= ps2_data[3];
624 		client->bufsiz = 4;
625 		break;
626 
627 	case MOUSEDEV_EMUL_PS2:
628 	default:
629 		ps2_data[0] |=
630 			((p->buttons & 0x10) >> 3) | ((p->buttons & 0x08) >> 1);
631 		p->dz = 0;
632 		client->bufsiz = 3;
633 		break;
634 	}
635 
636 	if (!p->dx && !p->dy && !p->dz) {
637 		if (client->tail == client->head) {
638 			client->ready = 0;
639 			client->last_buttons = p->buttons;
640 		} else
641 			client->tail = (client->tail + 1) % PACKET_QUEUE_LEN;
642 	}
643 }
644 
645 static void mousedev_generate_response(struct mousedev_client *client,
646 					int command)
647 {
648 	client->ps2[0] = 0xfa; /* ACK */
649 
650 	switch (command) {
651 
652 	case 0xeb: /* Poll */
653 		mousedev_packet(client, &client->ps2[1]);
654 		client->bufsiz++; /* account for leading ACK */
655 		break;
656 
657 	case 0xf2: /* Get ID */
658 		switch (client->mode) {
659 		case MOUSEDEV_EMUL_PS2:
660 			client->ps2[1] = 0;
661 			break;
662 		case MOUSEDEV_EMUL_IMPS:
663 			client->ps2[1] = 3;
664 			break;
665 		case MOUSEDEV_EMUL_EXPS:
666 			client->ps2[1] = 4;
667 			break;
668 		}
669 		client->bufsiz = 2;
670 		break;
671 
672 	case 0xe9: /* Get info */
673 		client->ps2[1] = 0x60; client->ps2[2] = 3; client->ps2[3] = 200;
674 		client->bufsiz = 4;
675 		break;
676 
677 	case 0xff: /* Reset */
678 		client->impsseq = client->imexseq = 0;
679 		client->mode = MOUSEDEV_EMUL_PS2;
680 		client->ps2[1] = 0xaa; client->ps2[2] = 0x00;
681 		client->bufsiz = 3;
682 		break;
683 
684 	default:
685 		client->bufsiz = 1;
686 		break;
687 	}
688 	client->buffer = client->bufsiz;
689 }
690 
691 static ssize_t mousedev_write(struct file *file, const char __user *buffer,
692 				size_t count, loff_t *ppos)
693 {
694 	struct mousedev_client *client = file->private_data;
695 	unsigned char c;
696 	unsigned int i;
697 
698 	for (i = 0; i < count; i++) {
699 
700 		if (get_user(c, buffer + i))
701 			return -EFAULT;
702 
703 		spin_lock_irq(&client->packet_lock);
704 
705 		if (c == mousedev_imex_seq[client->imexseq]) {
706 			if (++client->imexseq == MOUSEDEV_SEQ_LEN) {
707 				client->imexseq = 0;
708 				client->mode = MOUSEDEV_EMUL_EXPS;
709 			}
710 		} else
711 			client->imexseq = 0;
712 
713 		if (c == mousedev_imps_seq[client->impsseq]) {
714 			if (++client->impsseq == MOUSEDEV_SEQ_LEN) {
715 				client->impsseq = 0;
716 				client->mode = MOUSEDEV_EMUL_IMPS;
717 			}
718 		} else
719 			client->impsseq = 0;
720 
721 		mousedev_generate_response(client, c);
722 
723 		spin_unlock_irq(&client->packet_lock);
724 	}
725 
726 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
727 	wake_up_interruptible(&client->mousedev->wait);
728 
729 	return count;
730 }
731 
732 static ssize_t mousedev_read(struct file *file, char __user *buffer,
733 			     size_t count, loff_t *ppos)
734 {
735 	struct mousedev_client *client = file->private_data;
736 	struct mousedev *mousedev = client->mousedev;
737 	signed char data[sizeof(client->ps2)];
738 	int retval = 0;
739 
740 	if (!client->ready && !client->buffer && mousedev->exist &&
741 	    (file->f_flags & O_NONBLOCK))
742 		return -EAGAIN;
743 
744 	retval = wait_event_interruptible(mousedev->wait,
745 			!mousedev->exist || client->ready || client->buffer);
746 	if (retval)
747 		return retval;
748 
749 	if (!mousedev->exist)
750 		return -ENODEV;
751 
752 	spin_lock_irq(&client->packet_lock);
753 
754 	if (!client->buffer && client->ready) {
755 		mousedev_packet(client, client->ps2);
756 		client->buffer = client->bufsiz;
757 	}
758 
759 	if (count > client->buffer)
760 		count = client->buffer;
761 
762 	memcpy(data, client->ps2 + client->bufsiz - client->buffer, count);
763 	client->buffer -= count;
764 
765 	spin_unlock_irq(&client->packet_lock);
766 
767 	if (copy_to_user(buffer, data, count))
768 		return -EFAULT;
769 
770 	return count;
771 }
772 
773 /* No kernel lock - fine */
774 static unsigned int mousedev_poll(struct file *file, poll_table *wait)
775 {
776 	struct mousedev_client *client = file->private_data;
777 	struct mousedev *mousedev = client->mousedev;
778 	unsigned int mask;
779 
780 	poll_wait(file, &mousedev->wait, wait);
781 
782 	mask = mousedev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
783 	if (client->ready || client->buffer)
784 		mask |= POLLIN | POLLRDNORM;
785 
786 	return mask;
787 }
788 
789 static const struct file_operations mousedev_fops = {
790 	.owner =	THIS_MODULE,
791 	.read =		mousedev_read,
792 	.write =	mousedev_write,
793 	.poll =		mousedev_poll,
794 	.open =		mousedev_open,
795 	.release =	mousedev_release,
796 	.fasync =	mousedev_fasync,
797 	.llseek = noop_llseek,
798 };
799 
800 static int mousedev_install_chrdev(struct mousedev *mousedev)
801 {
802 	mousedev_table[mousedev->minor] = mousedev;
803 	return 0;
804 }
805 
806 static void mousedev_remove_chrdev(struct mousedev *mousedev)
807 {
808 	mutex_lock(&mousedev_table_mutex);
809 	mousedev_table[mousedev->minor] = NULL;
810 	mutex_unlock(&mousedev_table_mutex);
811 }
812 
813 /*
814  * Mark device non-existent. This disables writes, ioctls and
815  * prevents new users from opening the device. Already posted
816  * blocking reads will stay, however new ones will fail.
817  */
818 static void mousedev_mark_dead(struct mousedev *mousedev)
819 {
820 	mutex_lock(&mousedev->mutex);
821 	mousedev->exist = false;
822 	mutex_unlock(&mousedev->mutex);
823 }
824 
825 /*
826  * Wake up users waiting for IO so they can disconnect from
827  * dead device.
828  */
829 static void mousedev_hangup(struct mousedev *mousedev)
830 {
831 	struct mousedev_client *client;
832 
833 	spin_lock(&mousedev->client_lock);
834 	list_for_each_entry(client, &mousedev->client_list, node)
835 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
836 	spin_unlock(&mousedev->client_lock);
837 
838 	wake_up_interruptible(&mousedev->wait);
839 }
840 
841 static void mousedev_cleanup(struct mousedev *mousedev)
842 {
843 	struct input_handle *handle = &mousedev->handle;
844 
845 	mousedev_mark_dead(mousedev);
846 	mousedev_hangup(mousedev);
847 	mousedev_remove_chrdev(mousedev);
848 
849 	/* mousedev is marked dead so no one else accesses mousedev->open */
850 	if (mousedev->open)
851 		input_close_device(handle);
852 }
853 
854 static struct mousedev *mousedev_create(struct input_dev *dev,
855 					struct input_handler *handler,
856 					int minor)
857 {
858 	struct mousedev *mousedev;
859 	int error;
860 
861 	mousedev = kzalloc(sizeof(struct mousedev), GFP_KERNEL);
862 	if (!mousedev) {
863 		error = -ENOMEM;
864 		goto err_out;
865 	}
866 
867 	INIT_LIST_HEAD(&mousedev->client_list);
868 	INIT_LIST_HEAD(&mousedev->mixdev_node);
869 	spin_lock_init(&mousedev->client_lock);
870 	mutex_init(&mousedev->mutex);
871 	lockdep_set_subclass(&mousedev->mutex,
872 			     minor == MOUSEDEV_MIX ? SINGLE_DEPTH_NESTING : 0);
873 	init_waitqueue_head(&mousedev->wait);
874 
875 	if (minor == MOUSEDEV_MIX)
876 		dev_set_name(&mousedev->dev, "mice");
877 	else
878 		dev_set_name(&mousedev->dev, "mouse%d", minor);
879 
880 	mousedev->minor = minor;
881 	mousedev->exist = true;
882 	mousedev->handle.dev = input_get_device(dev);
883 	mousedev->handle.name = dev_name(&mousedev->dev);
884 	mousedev->handle.handler = handler;
885 	mousedev->handle.private = mousedev;
886 
887 	mousedev->dev.class = &input_class;
888 	if (dev)
889 		mousedev->dev.parent = &dev->dev;
890 	mousedev->dev.devt = MKDEV(INPUT_MAJOR, MOUSEDEV_MINOR_BASE + minor);
891 	mousedev->dev.release = mousedev_free;
892 	device_initialize(&mousedev->dev);
893 
894 	if (minor != MOUSEDEV_MIX) {
895 		error = input_register_handle(&mousedev->handle);
896 		if (error)
897 			goto err_free_mousedev;
898 	}
899 
900 	error = mousedev_install_chrdev(mousedev);
901 	if (error)
902 		goto err_unregister_handle;
903 
904 	error = device_add(&mousedev->dev);
905 	if (error)
906 		goto err_cleanup_mousedev;
907 
908 	return mousedev;
909 
910  err_cleanup_mousedev:
911 	mousedev_cleanup(mousedev);
912  err_unregister_handle:
913 	if (minor != MOUSEDEV_MIX)
914 		input_unregister_handle(&mousedev->handle);
915  err_free_mousedev:
916 	put_device(&mousedev->dev);
917  err_out:
918 	return ERR_PTR(error);
919 }
920 
921 static void mousedev_destroy(struct mousedev *mousedev)
922 {
923 	device_del(&mousedev->dev);
924 	mousedev_cleanup(mousedev);
925 	if (mousedev->minor != MOUSEDEV_MIX)
926 		input_unregister_handle(&mousedev->handle);
927 	put_device(&mousedev->dev);
928 }
929 
930 static int mixdev_add_device(struct mousedev *mousedev)
931 {
932 	int retval;
933 
934 	retval = mutex_lock_interruptible(&mousedev_mix->mutex);
935 	if (retval)
936 		return retval;
937 
938 	if (mousedev_mix->open) {
939 		retval = mousedev_open_device(mousedev);
940 		if (retval)
941 			goto out;
942 
943 		mousedev->mixdev_open = 1;
944 	}
945 
946 	get_device(&mousedev->dev);
947 	list_add_tail(&mousedev->mixdev_node, &mousedev_mix_list);
948 
949  out:
950 	mutex_unlock(&mousedev_mix->mutex);
951 	return retval;
952 }
953 
954 static void mixdev_remove_device(struct mousedev *mousedev)
955 {
956 	mutex_lock(&mousedev_mix->mutex);
957 
958 	if (mousedev->mixdev_open) {
959 		mousedev->mixdev_open = 0;
960 		mousedev_close_device(mousedev);
961 	}
962 
963 	list_del_init(&mousedev->mixdev_node);
964 	mutex_unlock(&mousedev_mix->mutex);
965 
966 	put_device(&mousedev->dev);
967 }
968 
969 static int mousedev_connect(struct input_handler *handler,
970 			    struct input_dev *dev,
971 			    const struct input_device_id *id)
972 {
973 	struct mousedev *mousedev;
974 	int minor;
975 	int error;
976 
977 	for (minor = 0; minor < MOUSEDEV_MINORS; minor++)
978 		if (!mousedev_table[minor])
979 			break;
980 
981 	if (minor == MOUSEDEV_MINORS) {
982 		pr_err("no more free mousedev devices\n");
983 		return -ENFILE;
984 	}
985 
986 	mousedev = mousedev_create(dev, handler, minor);
987 	if (IS_ERR(mousedev))
988 		return PTR_ERR(mousedev);
989 
990 	error = mixdev_add_device(mousedev);
991 	if (error) {
992 		mousedev_destroy(mousedev);
993 		return error;
994 	}
995 
996 	return 0;
997 }
998 
999 static void mousedev_disconnect(struct input_handle *handle)
1000 {
1001 	struct mousedev *mousedev = handle->private;
1002 
1003 	mixdev_remove_device(mousedev);
1004 	mousedev_destroy(mousedev);
1005 }
1006 
1007 static const struct input_device_id mousedev_ids[] = {
1008 	{
1009 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1010 				INPUT_DEVICE_ID_MATCH_KEYBIT |
1011 				INPUT_DEVICE_ID_MATCH_RELBIT,
1012 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) },
1013 		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
1014 		.relbit = { BIT_MASK(REL_X) | BIT_MASK(REL_Y) },
1015 	},	/* A mouse like device, at least one button,
1016 		   two relative axes */
1017 	{
1018 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1019 				INPUT_DEVICE_ID_MATCH_RELBIT,
1020 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) },
1021 		.relbit = { BIT_MASK(REL_WHEEL) },
1022 	},	/* A separate scrollwheel */
1023 	{
1024 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1025 				INPUT_DEVICE_ID_MATCH_KEYBIT |
1026 				INPUT_DEVICE_ID_MATCH_ABSBIT,
1027 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
1028 		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
1029 		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) },
1030 	},	/* A tablet like device, at least touch detection,
1031 		   two absolute axes */
1032 	{
1033 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1034 				INPUT_DEVICE_ID_MATCH_KEYBIT |
1035 				INPUT_DEVICE_ID_MATCH_ABSBIT,
1036 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
1037 		.keybit = { [BIT_WORD(BTN_TOOL_FINGER)] =
1038 				BIT_MASK(BTN_TOOL_FINGER) },
1039 		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
1040 				BIT_MASK(ABS_PRESSURE) |
1041 				BIT_MASK(ABS_TOOL_WIDTH) },
1042 	},	/* A touchpad */
1043 	{
1044 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1045 			INPUT_DEVICE_ID_MATCH_KEYBIT |
1046 			INPUT_DEVICE_ID_MATCH_ABSBIT,
1047 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
1048 		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
1049 		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) },
1050 	},	/* Mouse-like device with absolute X and Y but ordinary
1051 		   clicks, like hp ILO2 High Performance mouse */
1052 
1053 	{ },	/* Terminating entry */
1054 };
1055 
1056 MODULE_DEVICE_TABLE(input, mousedev_ids);
1057 
1058 static struct input_handler mousedev_handler = {
1059 	.event =	mousedev_event,
1060 	.connect =	mousedev_connect,
1061 	.disconnect =	mousedev_disconnect,
1062 	.fops =		&mousedev_fops,
1063 	.minor =	MOUSEDEV_MINOR_BASE,
1064 	.name =		"mousedev",
1065 	.id_table =	mousedev_ids,
1066 };
1067 
1068 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
1069 static struct miscdevice psaux_mouse = {
1070 	PSMOUSE_MINOR, "psaux", &mousedev_fops
1071 };
1072 static int psaux_registered;
1073 #endif
1074 
1075 static int __init mousedev_init(void)
1076 {
1077 	int error;
1078 
1079 	mousedev_mix = mousedev_create(NULL, &mousedev_handler, MOUSEDEV_MIX);
1080 	if (IS_ERR(mousedev_mix))
1081 		return PTR_ERR(mousedev_mix);
1082 
1083 	error = input_register_handler(&mousedev_handler);
1084 	if (error) {
1085 		mousedev_destroy(mousedev_mix);
1086 		return error;
1087 	}
1088 
1089 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
1090 	error = misc_register(&psaux_mouse);
1091 	if (error)
1092 		pr_warning("could not register psaux device, error: %d\n",
1093 			   error);
1094 	else
1095 		psaux_registered = 1;
1096 #endif
1097 
1098 	pr_info("PS/2 mouse device common for all mice\n");
1099 
1100 	return 0;
1101 }
1102 
1103 static void __exit mousedev_exit(void)
1104 {
1105 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
1106 	if (psaux_registered)
1107 		misc_deregister(&psaux_mouse);
1108 #endif
1109 	input_unregister_handler(&mousedev_handler);
1110 	mousedev_destroy(mousedev_mix);
1111 }
1112 
1113 module_init(mousedev_init);
1114 module_exit(mousedev_exit);
1115