xref: /openbmc/linux/drivers/input/mousedev.c (revision cfbb9be8)
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		31
16 #define MOUSEDEV_MIX		63
17 
18 #include <linux/bitops.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/poll.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/input.h>
25 #include <linux/random.h>
26 #include <linux/major.h>
27 #include <linux/device.h>
28 #include <linux/cdev.h>
29 #include <linux/kernel.h>
30 
31 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
32 MODULE_DESCRIPTION("Mouse (ExplorerPS/2) device interfaces");
33 MODULE_LICENSE("GPL");
34 
35 #ifndef CONFIG_INPUT_MOUSEDEV_SCREEN_X
36 #define CONFIG_INPUT_MOUSEDEV_SCREEN_X	1024
37 #endif
38 #ifndef CONFIG_INPUT_MOUSEDEV_SCREEN_Y
39 #define CONFIG_INPUT_MOUSEDEV_SCREEN_Y	768
40 #endif
41 
42 static int xres = CONFIG_INPUT_MOUSEDEV_SCREEN_X;
43 module_param(xres, uint, 0644);
44 MODULE_PARM_DESC(xres, "Horizontal screen resolution");
45 
46 static int yres = CONFIG_INPUT_MOUSEDEV_SCREEN_Y;
47 module_param(yres, uint, 0644);
48 MODULE_PARM_DESC(yres, "Vertical screen resolution");
49 
50 static unsigned tap_time = 200;
51 module_param(tap_time, uint, 0644);
52 MODULE_PARM_DESC(tap_time, "Tap time for touchpads in absolute mode (msecs)");
53 
54 struct mousedev_hw_data {
55 	int dx, dy, dz;
56 	int x, y;
57 	int abs_event;
58 	unsigned long buttons;
59 };
60 
61 struct mousedev {
62 	int open;
63 	struct input_handle handle;
64 	wait_queue_head_t wait;
65 	struct list_head client_list;
66 	spinlock_t client_lock; /* protects client_list */
67 	struct mutex mutex;
68 	struct device dev;
69 	struct cdev cdev;
70 	bool exist;
71 
72 	struct list_head mixdev_node;
73 	bool opened_by_mixdev;
74 
75 	struct mousedev_hw_data packet;
76 	unsigned int pkt_count;
77 	int old_x[4], old_y[4];
78 	int frac_dx, frac_dy;
79 	unsigned long touch;
80 
81 	int (*open_device)(struct mousedev *mousedev);
82 	void (*close_device)(struct mousedev *mousedev);
83 };
84 
85 enum mousedev_emul {
86 	MOUSEDEV_EMUL_PS2,
87 	MOUSEDEV_EMUL_IMPS,
88 	MOUSEDEV_EMUL_EXPS
89 };
90 
91 struct mousedev_motion {
92 	int dx, dy, dz;
93 	unsigned long buttons;
94 };
95 
96 #define PACKET_QUEUE_LEN	16
97 struct mousedev_client {
98 	struct fasync_struct *fasync;
99 	struct mousedev *mousedev;
100 	struct list_head node;
101 
102 	struct mousedev_motion packets[PACKET_QUEUE_LEN];
103 	unsigned int head, tail;
104 	spinlock_t packet_lock;
105 	int pos_x, pos_y;
106 
107 	u8 ps2[6];
108 	unsigned char ready, buffer, bufsiz;
109 	unsigned char imexseq, impsseq;
110 	enum mousedev_emul mode;
111 	unsigned long last_buttons;
112 };
113 
114 #define MOUSEDEV_SEQ_LEN	6
115 
116 static unsigned char mousedev_imps_seq[] = { 0xf3, 200, 0xf3, 100, 0xf3, 80 };
117 static unsigned char mousedev_imex_seq[] = { 0xf3, 200, 0xf3, 200, 0xf3, 80 };
118 
119 static struct mousedev *mousedev_mix;
120 static LIST_HEAD(mousedev_mix_list);
121 
122 #define fx(i)  (mousedev->old_x[(mousedev->pkt_count - (i)) & 03])
123 #define fy(i)  (mousedev->old_y[(mousedev->pkt_count - (i)) & 03])
124 
125 static void mousedev_touchpad_event(struct input_dev *dev,
126 				    struct mousedev *mousedev,
127 				    unsigned int code, int value)
128 {
129 	int size, tmp;
130 	enum { FRACTION_DENOM = 128 };
131 
132 	switch (code) {
133 
134 	case ABS_X:
135 
136 		fx(0) = value;
137 		if (mousedev->touch && mousedev->pkt_count >= 2) {
138 			size = input_abs_get_max(dev, ABS_X) -
139 					input_abs_get_min(dev, ABS_X);
140 			if (size == 0)
141 				size = 256 * 2;
142 
143 			tmp = ((value - fx(2)) * 256 * FRACTION_DENOM) / size;
144 			tmp += mousedev->frac_dx;
145 			mousedev->packet.dx = tmp / FRACTION_DENOM;
146 			mousedev->frac_dx =
147 				tmp - mousedev->packet.dx * FRACTION_DENOM;
148 		}
149 		break;
150 
151 	case ABS_Y:
152 		fy(0) = value;
153 		if (mousedev->touch && mousedev->pkt_count >= 2) {
154 			/* use X size for ABS_Y to keep the same scale */
155 			size = input_abs_get_max(dev, ABS_X) -
156 					input_abs_get_min(dev, ABS_X);
157 			if (size == 0)
158 				size = 256 * 2;
159 
160 			tmp = -((value - fy(2)) * 256 * FRACTION_DENOM) / size;
161 			tmp += mousedev->frac_dy;
162 			mousedev->packet.dy = tmp / FRACTION_DENOM;
163 			mousedev->frac_dy = tmp -
164 				mousedev->packet.dy * FRACTION_DENOM;
165 		}
166 		break;
167 	}
168 }
169 
170 static void mousedev_abs_event(struct input_dev *dev, struct mousedev *mousedev,
171 				unsigned int code, int value)
172 {
173 	int min, max, size;
174 
175 	switch (code) {
176 
177 	case ABS_X:
178 		min = input_abs_get_min(dev, ABS_X);
179 		max = input_abs_get_max(dev, ABS_X);
180 
181 		size = max - min;
182 		if (size == 0)
183 			size = xres ? : 1;
184 
185 		value = clamp(value, min, max);
186 
187 		mousedev->packet.x = ((value - min) * xres) / size;
188 		mousedev->packet.abs_event = 1;
189 		break;
190 
191 	case ABS_Y:
192 		min = input_abs_get_min(dev, ABS_Y);
193 		max = input_abs_get_max(dev, ABS_Y);
194 
195 		size = max - min;
196 		if (size == 0)
197 			size = yres ? : 1;
198 
199 		value = clamp(value, min, max);
200 
201 		mousedev->packet.y = yres - ((value - min) * yres) / size;
202 		mousedev->packet.abs_event = 1;
203 		break;
204 	}
205 }
206 
207 static void mousedev_rel_event(struct mousedev *mousedev,
208 				unsigned int code, int value)
209 {
210 	switch (code) {
211 	case REL_X:
212 		mousedev->packet.dx += value;
213 		break;
214 
215 	case REL_Y:
216 		mousedev->packet.dy -= value;
217 		break;
218 
219 	case REL_WHEEL:
220 		mousedev->packet.dz -= value;
221 		break;
222 	}
223 }
224 
225 static void mousedev_key_event(struct mousedev *mousedev,
226 				unsigned int code, int value)
227 {
228 	int index;
229 
230 	switch (code) {
231 
232 	case BTN_TOUCH:
233 	case BTN_0:
234 	case BTN_LEFT:		index = 0; break;
235 
236 	case BTN_STYLUS:
237 	case BTN_1:
238 	case BTN_RIGHT:		index = 1; break;
239 
240 	case BTN_2:
241 	case BTN_FORWARD:
242 	case BTN_STYLUS2:
243 	case BTN_MIDDLE:	index = 2; break;
244 
245 	case BTN_3:
246 	case BTN_BACK:
247 	case BTN_SIDE:		index = 3; break;
248 
249 	case BTN_4:
250 	case BTN_EXTRA:		index = 4; break;
251 
252 	default:		return;
253 	}
254 
255 	if (value) {
256 		set_bit(index, &mousedev->packet.buttons);
257 		set_bit(index, &mousedev_mix->packet.buttons);
258 	} else {
259 		clear_bit(index, &mousedev->packet.buttons);
260 		clear_bit(index, &mousedev_mix->packet.buttons);
261 	}
262 }
263 
264 static void mousedev_notify_readers(struct mousedev *mousedev,
265 				    struct mousedev_hw_data *packet)
266 {
267 	struct mousedev_client *client;
268 	struct mousedev_motion *p;
269 	unsigned int new_head;
270 	int wake_readers = 0;
271 
272 	rcu_read_lock();
273 	list_for_each_entry_rcu(client, &mousedev->client_list, node) {
274 
275 		/* Just acquire the lock, interrupts already disabled */
276 		spin_lock(&client->packet_lock);
277 
278 		p = &client->packets[client->head];
279 		if (client->ready && p->buttons != mousedev->packet.buttons) {
280 			new_head = (client->head + 1) % PACKET_QUEUE_LEN;
281 			if (new_head != client->tail) {
282 				p = &client->packets[client->head = new_head];
283 				memset(p, 0, sizeof(struct mousedev_motion));
284 			}
285 		}
286 
287 		if (packet->abs_event) {
288 			p->dx += packet->x - client->pos_x;
289 			p->dy += packet->y - client->pos_y;
290 			client->pos_x = packet->x;
291 			client->pos_y = packet->y;
292 		}
293 
294 		client->pos_x += packet->dx;
295 		client->pos_x = clamp_val(client->pos_x, 0, xres);
296 
297 		client->pos_y += packet->dy;
298 		client->pos_y = clamp_val(client->pos_y, 0, yres);
299 
300 		p->dx += packet->dx;
301 		p->dy += packet->dy;
302 		p->dz += packet->dz;
303 		p->buttons = mousedev->packet.buttons;
304 
305 		if (p->dx || p->dy || p->dz ||
306 		    p->buttons != client->last_buttons)
307 			client->ready = 1;
308 
309 		spin_unlock(&client->packet_lock);
310 
311 		if (client->ready) {
312 			kill_fasync(&client->fasync, SIGIO, POLL_IN);
313 			wake_readers = 1;
314 		}
315 	}
316 	rcu_read_unlock();
317 
318 	if (wake_readers)
319 		wake_up_interruptible(&mousedev->wait);
320 }
321 
322 static void mousedev_touchpad_touch(struct mousedev *mousedev, int value)
323 {
324 	if (!value) {
325 		if (mousedev->touch &&
326 		    time_before(jiffies,
327 				mousedev->touch + msecs_to_jiffies(tap_time))) {
328 			/*
329 			 * Toggle left button to emulate tap.
330 			 * We rely on the fact that mousedev_mix always has 0
331 			 * motion packet so we won't mess current position.
332 			 */
333 			set_bit(0, &mousedev->packet.buttons);
334 			set_bit(0, &mousedev_mix->packet.buttons);
335 			mousedev_notify_readers(mousedev, &mousedev_mix->packet);
336 			mousedev_notify_readers(mousedev_mix,
337 						&mousedev_mix->packet);
338 			clear_bit(0, &mousedev->packet.buttons);
339 			clear_bit(0, &mousedev_mix->packet.buttons);
340 		}
341 		mousedev->touch = mousedev->pkt_count = 0;
342 		mousedev->frac_dx = 0;
343 		mousedev->frac_dy = 0;
344 
345 	} else if (!mousedev->touch)
346 		mousedev->touch = jiffies;
347 }
348 
349 static void mousedev_event(struct input_handle *handle,
350 			   unsigned int type, unsigned int code, int value)
351 {
352 	struct mousedev *mousedev = handle->private;
353 
354 	switch (type) {
355 
356 	case EV_ABS:
357 		/* Ignore joysticks */
358 		if (test_bit(BTN_TRIGGER, handle->dev->keybit))
359 			return;
360 
361 		if (test_bit(BTN_TOOL_FINGER, handle->dev->keybit))
362 			mousedev_touchpad_event(handle->dev,
363 						mousedev, code, value);
364 		else
365 			mousedev_abs_event(handle->dev, mousedev, code, value);
366 
367 		break;
368 
369 	case EV_REL:
370 		mousedev_rel_event(mousedev, code, value);
371 		break;
372 
373 	case EV_KEY:
374 		if (value != 2) {
375 			if (code == BTN_TOUCH &&
376 			    test_bit(BTN_TOOL_FINGER, handle->dev->keybit))
377 				mousedev_touchpad_touch(mousedev, value);
378 			else
379 				mousedev_key_event(mousedev, code, value);
380 		}
381 		break;
382 
383 	case EV_SYN:
384 		if (code == SYN_REPORT) {
385 			if (mousedev->touch) {
386 				mousedev->pkt_count++;
387 				/*
388 				 * Input system eats duplicate events,
389 				 * but we need all of them to do correct
390 				 * averaging so apply present one forward
391 				 */
392 				fx(0) = fx(1);
393 				fy(0) = fy(1);
394 			}
395 
396 			mousedev_notify_readers(mousedev, &mousedev->packet);
397 			mousedev_notify_readers(mousedev_mix, &mousedev->packet);
398 
399 			mousedev->packet.dx = mousedev->packet.dy =
400 				mousedev->packet.dz = 0;
401 			mousedev->packet.abs_event = 0;
402 		}
403 		break;
404 	}
405 }
406 
407 static int mousedev_fasync(int fd, struct file *file, int on)
408 {
409 	struct mousedev_client *client = file->private_data;
410 
411 	return fasync_helper(fd, file, on, &client->fasync);
412 }
413 
414 static void mousedev_free(struct device *dev)
415 {
416 	struct mousedev *mousedev = container_of(dev, struct mousedev, dev);
417 
418 	input_put_device(mousedev->handle.dev);
419 	kfree(mousedev);
420 }
421 
422 static int mousedev_open_device(struct mousedev *mousedev)
423 {
424 	int retval;
425 
426 	retval = mutex_lock_interruptible(&mousedev->mutex);
427 	if (retval)
428 		return retval;
429 
430 	if (!mousedev->exist)
431 		retval = -ENODEV;
432 	else if (!mousedev->open++) {
433 		retval = input_open_device(&mousedev->handle);
434 		if (retval)
435 			mousedev->open--;
436 	}
437 
438 	mutex_unlock(&mousedev->mutex);
439 	return retval;
440 }
441 
442 static void mousedev_close_device(struct mousedev *mousedev)
443 {
444 	mutex_lock(&mousedev->mutex);
445 
446 	if (mousedev->exist && !--mousedev->open)
447 		input_close_device(&mousedev->handle);
448 
449 	mutex_unlock(&mousedev->mutex);
450 }
451 
452 /*
453  * Open all available devices so they can all be multiplexed in one.
454  * stream. Note that this function is called with mousedev_mix->mutex
455  * held.
456  */
457 static int mixdev_open_devices(struct mousedev *mixdev)
458 {
459 	int error;
460 
461 	error = mutex_lock_interruptible(&mixdev->mutex);
462 	if (error)
463 		return error;
464 
465 	if (!mixdev->open++) {
466 		struct mousedev *mousedev;
467 
468 		list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
469 			if (!mousedev->opened_by_mixdev) {
470 				if (mousedev_open_device(mousedev))
471 					continue;
472 
473 				mousedev->opened_by_mixdev = true;
474 			}
475 		}
476 	}
477 
478 	mutex_unlock(&mixdev->mutex);
479 	return 0;
480 }
481 
482 /*
483  * Close all devices that were opened as part of multiplexed
484  * device. Note that this function is called with mousedev_mix->mutex
485  * held.
486  */
487 static void mixdev_close_devices(struct mousedev *mixdev)
488 {
489 	mutex_lock(&mixdev->mutex);
490 
491 	if (!--mixdev->open) {
492 		struct mousedev *mousedev;
493 
494 		list_for_each_entry(mousedev, &mousedev_mix_list, mixdev_node) {
495 			if (mousedev->opened_by_mixdev) {
496 				mousedev->opened_by_mixdev = false;
497 				mousedev_close_device(mousedev);
498 			}
499 		}
500 	}
501 
502 	mutex_unlock(&mixdev->mutex);
503 }
504 
505 
506 static void mousedev_attach_client(struct mousedev *mousedev,
507 				   struct mousedev_client *client)
508 {
509 	spin_lock(&mousedev->client_lock);
510 	list_add_tail_rcu(&client->node, &mousedev->client_list);
511 	spin_unlock(&mousedev->client_lock);
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 
533 	return 0;
534 }
535 
536 static int mousedev_open(struct inode *inode, struct file *file)
537 {
538 	struct mousedev_client *client;
539 	struct mousedev *mousedev;
540 	int error;
541 
542 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
543 	if (imajor(inode) == MISC_MAJOR)
544 		mousedev = mousedev_mix;
545 	else
546 #endif
547 		mousedev = container_of(inode->i_cdev, struct mousedev, cdev);
548 
549 	client = kzalloc(sizeof(struct mousedev_client), GFP_KERNEL);
550 	if (!client)
551 		return -ENOMEM;
552 
553 	spin_lock_init(&client->packet_lock);
554 	client->pos_x = xres / 2;
555 	client->pos_y = yres / 2;
556 	client->mousedev = mousedev;
557 	mousedev_attach_client(mousedev, client);
558 
559 	error = mousedev->open_device(mousedev);
560 	if (error)
561 		goto err_free_client;
562 
563 	file->private_data = client;
564 	nonseekable_open(inode, file);
565 
566 	return 0;
567 
568  err_free_client:
569 	mousedev_detach_client(mousedev, client);
570 	kfree(client);
571 	return error;
572 }
573 
574 static void mousedev_packet(struct mousedev_client *client, u8 *ps2_data)
575 {
576 	struct mousedev_motion *p = &client->packets[client->tail];
577 	s8 dx, dy, dz;
578 
579 	dx = clamp_val(p->dx, -127, 127);
580 	p->dx -= dx;
581 
582 	dy = clamp_val(p->dy, -127, 127);
583 	p->dy -= dy;
584 
585 	ps2_data[0] = BIT(3);
586 	ps2_data[0] |= ((dx & BIT(7)) >> 3) | ((dy & BIT(7)) >> 2);
587 	ps2_data[0] |= p->buttons & 0x07;
588 	ps2_data[1] = dx;
589 	ps2_data[2] = dy;
590 
591 	switch (client->mode) {
592 	case MOUSEDEV_EMUL_EXPS:
593 		dz = clamp_val(p->dz, -7, 7);
594 		p->dz -= dz;
595 
596 		ps2_data[3] = (dz & 0x0f) | ((p->buttons & 0x18) << 1);
597 		client->bufsiz = 4;
598 		break;
599 
600 	case MOUSEDEV_EMUL_IMPS:
601 		dz = clamp_val(p->dz, -127, 127);
602 		p->dz -= dz;
603 
604 		ps2_data[0] |= ((p->buttons & 0x10) >> 3) |
605 			       ((p->buttons & 0x08) >> 1);
606 		ps2_data[3] = dz;
607 
608 		client->bufsiz = 4;
609 		break;
610 
611 	case MOUSEDEV_EMUL_PS2:
612 	default:
613 		p->dz = 0;
614 
615 		ps2_data[0] |= ((p->buttons & 0x10) >> 3) |
616 			       ((p->buttons & 0x08) >> 1);
617 
618 		client->bufsiz = 3;
619 		break;
620 	}
621 
622 	if (!p->dx && !p->dy && !p->dz) {
623 		if (client->tail == client->head) {
624 			client->ready = 0;
625 			client->last_buttons = p->buttons;
626 		} else
627 			client->tail = (client->tail + 1) % PACKET_QUEUE_LEN;
628 	}
629 }
630 
631 static void mousedev_generate_response(struct mousedev_client *client,
632 					int command)
633 {
634 	client->ps2[0] = 0xfa; /* ACK */
635 
636 	switch (command) {
637 
638 	case 0xeb: /* Poll */
639 		mousedev_packet(client, &client->ps2[1]);
640 		client->bufsiz++; /* account for leading ACK */
641 		break;
642 
643 	case 0xf2: /* Get ID */
644 		switch (client->mode) {
645 		case MOUSEDEV_EMUL_PS2:
646 			client->ps2[1] = 0;
647 			break;
648 		case MOUSEDEV_EMUL_IMPS:
649 			client->ps2[1] = 3;
650 			break;
651 		case MOUSEDEV_EMUL_EXPS:
652 			client->ps2[1] = 4;
653 			break;
654 		}
655 		client->bufsiz = 2;
656 		break;
657 
658 	case 0xe9: /* Get info */
659 		client->ps2[1] = 0x60; client->ps2[2] = 3; client->ps2[3] = 200;
660 		client->bufsiz = 4;
661 		break;
662 
663 	case 0xff: /* Reset */
664 		client->impsseq = client->imexseq = 0;
665 		client->mode = MOUSEDEV_EMUL_PS2;
666 		client->ps2[1] = 0xaa; client->ps2[2] = 0x00;
667 		client->bufsiz = 3;
668 		break;
669 
670 	default:
671 		client->bufsiz = 1;
672 		break;
673 	}
674 	client->buffer = client->bufsiz;
675 }
676 
677 static ssize_t mousedev_write(struct file *file, const char __user *buffer,
678 				size_t count, loff_t *ppos)
679 {
680 	struct mousedev_client *client = file->private_data;
681 	unsigned char c;
682 	unsigned int i;
683 
684 	for (i = 0; i < count; i++) {
685 
686 		if (get_user(c, buffer + i))
687 			return -EFAULT;
688 
689 		spin_lock_irq(&client->packet_lock);
690 
691 		if (c == mousedev_imex_seq[client->imexseq]) {
692 			if (++client->imexseq == MOUSEDEV_SEQ_LEN) {
693 				client->imexseq = 0;
694 				client->mode = MOUSEDEV_EMUL_EXPS;
695 			}
696 		} else
697 			client->imexseq = 0;
698 
699 		if (c == mousedev_imps_seq[client->impsseq]) {
700 			if (++client->impsseq == MOUSEDEV_SEQ_LEN) {
701 				client->impsseq = 0;
702 				client->mode = MOUSEDEV_EMUL_IMPS;
703 			}
704 		} else
705 			client->impsseq = 0;
706 
707 		mousedev_generate_response(client, c);
708 
709 		spin_unlock_irq(&client->packet_lock);
710 	}
711 
712 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
713 	wake_up_interruptible(&client->mousedev->wait);
714 
715 	return count;
716 }
717 
718 static ssize_t mousedev_read(struct file *file, char __user *buffer,
719 			     size_t count, loff_t *ppos)
720 {
721 	struct mousedev_client *client = file->private_data;
722 	struct mousedev *mousedev = client->mousedev;
723 	u8 data[sizeof(client->ps2)];
724 	int retval = 0;
725 
726 	if (!client->ready && !client->buffer && mousedev->exist &&
727 	    (file->f_flags & O_NONBLOCK))
728 		return -EAGAIN;
729 
730 	retval = wait_event_interruptible(mousedev->wait,
731 			!mousedev->exist || client->ready || client->buffer);
732 	if (retval)
733 		return retval;
734 
735 	if (!mousedev->exist)
736 		return -ENODEV;
737 
738 	spin_lock_irq(&client->packet_lock);
739 
740 	if (!client->buffer && client->ready) {
741 		mousedev_packet(client, client->ps2);
742 		client->buffer = client->bufsiz;
743 	}
744 
745 	if (count > client->buffer)
746 		count = client->buffer;
747 
748 	memcpy(data, client->ps2 + client->bufsiz - client->buffer, count);
749 	client->buffer -= count;
750 
751 	spin_unlock_irq(&client->packet_lock);
752 
753 	if (copy_to_user(buffer, data, count))
754 		return -EFAULT;
755 
756 	return count;
757 }
758 
759 /* No kernel lock - fine */
760 static __poll_t mousedev_poll(struct file *file, poll_table *wait)
761 {
762 	struct mousedev_client *client = file->private_data;
763 	struct mousedev *mousedev = client->mousedev;
764 	__poll_t mask;
765 
766 	poll_wait(file, &mousedev->wait, wait);
767 
768 	mask = mousedev->exist ? EPOLLOUT | EPOLLWRNORM : EPOLLHUP | EPOLLERR;
769 	if (client->ready || client->buffer)
770 		mask |= EPOLLIN | EPOLLRDNORM;
771 
772 	return mask;
773 }
774 
775 static const struct file_operations mousedev_fops = {
776 	.owner		= THIS_MODULE,
777 	.read		= mousedev_read,
778 	.write		= mousedev_write,
779 	.poll		= mousedev_poll,
780 	.open		= mousedev_open,
781 	.release	= mousedev_release,
782 	.fasync		= mousedev_fasync,
783 	.llseek		= noop_llseek,
784 };
785 
786 /*
787  * Mark device non-existent. This disables writes, ioctls and
788  * prevents new users from opening the device. Already posted
789  * blocking reads will stay, however new ones will fail.
790  */
791 static void mousedev_mark_dead(struct mousedev *mousedev)
792 {
793 	mutex_lock(&mousedev->mutex);
794 	mousedev->exist = false;
795 	mutex_unlock(&mousedev->mutex);
796 }
797 
798 /*
799  * Wake up users waiting for IO so they can disconnect from
800  * dead device.
801  */
802 static void mousedev_hangup(struct mousedev *mousedev)
803 {
804 	struct mousedev_client *client;
805 
806 	spin_lock(&mousedev->client_lock);
807 	list_for_each_entry(client, &mousedev->client_list, node)
808 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
809 	spin_unlock(&mousedev->client_lock);
810 
811 	wake_up_interruptible(&mousedev->wait);
812 }
813 
814 static void mousedev_cleanup(struct mousedev *mousedev)
815 {
816 	struct input_handle *handle = &mousedev->handle;
817 
818 	mousedev_mark_dead(mousedev);
819 	mousedev_hangup(mousedev);
820 
821 	/* mousedev is marked dead so no one else accesses mousedev->open */
822 	if (mousedev->open)
823 		input_close_device(handle);
824 }
825 
826 static int mousedev_reserve_minor(bool mixdev)
827 {
828 	int minor;
829 
830 	if (mixdev) {
831 		minor = input_get_new_minor(MOUSEDEV_MIX, 1, false);
832 		if (minor < 0)
833 			pr_err("failed to reserve mixdev minor: %d\n", minor);
834 	} else {
835 		minor = input_get_new_minor(MOUSEDEV_MINOR_BASE,
836 					    MOUSEDEV_MINORS, true);
837 		if (minor < 0)
838 			pr_err("failed to reserve new minor: %d\n", minor);
839 	}
840 
841 	return minor;
842 }
843 
844 static struct mousedev *mousedev_create(struct input_dev *dev,
845 					struct input_handler *handler,
846 					bool mixdev)
847 {
848 	struct mousedev *mousedev;
849 	int minor;
850 	int error;
851 
852 	minor = mousedev_reserve_minor(mixdev);
853 	if (minor < 0) {
854 		error = minor;
855 		goto err_out;
856 	}
857 
858 	mousedev = kzalloc(sizeof(struct mousedev), GFP_KERNEL);
859 	if (!mousedev) {
860 		error = -ENOMEM;
861 		goto err_free_minor;
862 	}
863 
864 	INIT_LIST_HEAD(&mousedev->client_list);
865 	INIT_LIST_HEAD(&mousedev->mixdev_node);
866 	spin_lock_init(&mousedev->client_lock);
867 	mutex_init(&mousedev->mutex);
868 	lockdep_set_subclass(&mousedev->mutex,
869 			     mixdev ? SINGLE_DEPTH_NESTING : 0);
870 	init_waitqueue_head(&mousedev->wait);
871 
872 	if (mixdev) {
873 		dev_set_name(&mousedev->dev, "mice");
874 
875 		mousedev->open_device = mixdev_open_devices;
876 		mousedev->close_device = mixdev_close_devices;
877 	} else {
878 		int dev_no = minor;
879 		/* Normalize device number if it falls into legacy range */
880 		if (dev_no < MOUSEDEV_MINOR_BASE + MOUSEDEV_MINORS)
881 			dev_no -= MOUSEDEV_MINOR_BASE;
882 		dev_set_name(&mousedev->dev, "mouse%d", dev_no);
883 
884 		mousedev->open_device = mousedev_open_device;
885 		mousedev->close_device = mousedev_close_device;
886 	}
887 
888 	mousedev->exist = true;
889 	mousedev->handle.dev = input_get_device(dev);
890 	mousedev->handle.name = dev_name(&mousedev->dev);
891 	mousedev->handle.handler = handler;
892 	mousedev->handle.private = mousedev;
893 
894 	mousedev->dev.class = &input_class;
895 	if (dev)
896 		mousedev->dev.parent = &dev->dev;
897 	mousedev->dev.devt = MKDEV(INPUT_MAJOR, minor);
898 	mousedev->dev.release = mousedev_free;
899 	device_initialize(&mousedev->dev);
900 
901 	if (!mixdev) {
902 		error = input_register_handle(&mousedev->handle);
903 		if (error)
904 			goto err_free_mousedev;
905 	}
906 
907 	cdev_init(&mousedev->cdev, &mousedev_fops);
908 
909 	error = cdev_device_add(&mousedev->cdev, &mousedev->dev);
910 	if (error)
911 		goto err_cleanup_mousedev;
912 
913 	return mousedev;
914 
915  err_cleanup_mousedev:
916 	mousedev_cleanup(mousedev);
917 	if (!mixdev)
918 		input_unregister_handle(&mousedev->handle);
919  err_free_mousedev:
920 	put_device(&mousedev->dev);
921  err_free_minor:
922 	input_free_minor(minor);
923  err_out:
924 	return ERR_PTR(error);
925 }
926 
927 static void mousedev_destroy(struct mousedev *mousedev)
928 {
929 	cdev_device_del(&mousedev->cdev, &mousedev->dev);
930 	mousedev_cleanup(mousedev);
931 	input_free_minor(MINOR(mousedev->dev.devt));
932 	if (mousedev != mousedev_mix)
933 		input_unregister_handle(&mousedev->handle);
934 	put_device(&mousedev->dev);
935 }
936 
937 static int mixdev_add_device(struct mousedev *mousedev)
938 {
939 	int retval;
940 
941 	retval = mutex_lock_interruptible(&mousedev_mix->mutex);
942 	if (retval)
943 		return retval;
944 
945 	if (mousedev_mix->open) {
946 		retval = mousedev_open_device(mousedev);
947 		if (retval)
948 			goto out;
949 
950 		mousedev->opened_by_mixdev = true;
951 	}
952 
953 	get_device(&mousedev->dev);
954 	list_add_tail(&mousedev->mixdev_node, &mousedev_mix_list);
955 
956  out:
957 	mutex_unlock(&mousedev_mix->mutex);
958 	return retval;
959 }
960 
961 static void mixdev_remove_device(struct mousedev *mousedev)
962 {
963 	mutex_lock(&mousedev_mix->mutex);
964 
965 	if (mousedev->opened_by_mixdev) {
966 		mousedev->opened_by_mixdev = false;
967 		mousedev_close_device(mousedev);
968 	}
969 
970 	list_del_init(&mousedev->mixdev_node);
971 	mutex_unlock(&mousedev_mix->mutex);
972 
973 	put_device(&mousedev->dev);
974 }
975 
976 static int mousedev_connect(struct input_handler *handler,
977 			    struct input_dev *dev,
978 			    const struct input_device_id *id)
979 {
980 	struct mousedev *mousedev;
981 	int error;
982 
983 	mousedev = mousedev_create(dev, handler, false);
984 	if (IS_ERR(mousedev))
985 		return PTR_ERR(mousedev);
986 
987 	error = mixdev_add_device(mousedev);
988 	if (error) {
989 		mousedev_destroy(mousedev);
990 		return error;
991 	}
992 
993 	return 0;
994 }
995 
996 static void mousedev_disconnect(struct input_handle *handle)
997 {
998 	struct mousedev *mousedev = handle->private;
999 
1000 	mixdev_remove_device(mousedev);
1001 	mousedev_destroy(mousedev);
1002 }
1003 
1004 static const struct input_device_id mousedev_ids[] = {
1005 	{
1006 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1007 				INPUT_DEVICE_ID_MATCH_KEYBIT |
1008 				INPUT_DEVICE_ID_MATCH_RELBIT,
1009 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) },
1010 		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
1011 		.relbit = { BIT_MASK(REL_X) | BIT_MASK(REL_Y) },
1012 	},	/* A mouse like device, at least one button,
1013 		   two relative axes */
1014 	{
1015 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1016 				INPUT_DEVICE_ID_MATCH_RELBIT,
1017 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_REL) },
1018 		.relbit = { BIT_MASK(REL_WHEEL) },
1019 	},	/* A separate scrollwheel */
1020 	{
1021 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1022 				INPUT_DEVICE_ID_MATCH_KEYBIT |
1023 				INPUT_DEVICE_ID_MATCH_ABSBIT,
1024 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
1025 		.keybit = { [BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH) },
1026 		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) },
1027 	},	/* A tablet like device, at least touch detection,
1028 		   two absolute axes */
1029 	{
1030 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1031 				INPUT_DEVICE_ID_MATCH_KEYBIT |
1032 				INPUT_DEVICE_ID_MATCH_ABSBIT,
1033 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
1034 		.keybit = { [BIT_WORD(BTN_TOOL_FINGER)] =
1035 				BIT_MASK(BTN_TOOL_FINGER) },
1036 		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) |
1037 				BIT_MASK(ABS_PRESSURE) |
1038 				BIT_MASK(ABS_TOOL_WIDTH) },
1039 	},	/* A touchpad */
1040 	{
1041 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
1042 			INPUT_DEVICE_ID_MATCH_KEYBIT |
1043 			INPUT_DEVICE_ID_MATCH_ABSBIT,
1044 		.evbit = { BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS) },
1045 		.keybit = { [BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) },
1046 		.absbit = { BIT_MASK(ABS_X) | BIT_MASK(ABS_Y) },
1047 	},	/* Mouse-like device with absolute X and Y but ordinary
1048 		   clicks, like hp ILO2 High Performance mouse */
1049 
1050 	{ },	/* Terminating entry */
1051 };
1052 
1053 MODULE_DEVICE_TABLE(input, mousedev_ids);
1054 
1055 static struct input_handler mousedev_handler = {
1056 	.event		= mousedev_event,
1057 	.connect	= mousedev_connect,
1058 	.disconnect	= mousedev_disconnect,
1059 	.legacy_minors	= true,
1060 	.minor		= MOUSEDEV_MINOR_BASE,
1061 	.name		= "mousedev",
1062 	.id_table	= mousedev_ids,
1063 };
1064 
1065 #ifdef CONFIG_INPUT_MOUSEDEV_PSAUX
1066 #include <linux/miscdevice.h>
1067 
1068 static struct miscdevice psaux_mouse = {
1069 	.minor	= PSMOUSE_MINOR,
1070 	.name	= "psaux",
1071 	.fops	= &mousedev_fops,
1072 };
1073 
1074 static bool psaux_registered;
1075 
1076 static void __init mousedev_psaux_register(void)
1077 {
1078 	int error;
1079 
1080 	error = misc_register(&psaux_mouse);
1081 	if (error)
1082 		pr_warn("could not register psaux device, error: %d\n",
1083 			   error);
1084 	else
1085 		psaux_registered = true;
1086 }
1087 
1088 static void __exit mousedev_psaux_unregister(void)
1089 {
1090 	if (psaux_registered)
1091 		misc_deregister(&psaux_mouse);
1092 }
1093 #else
1094 static inline void mousedev_psaux_register(void) { }
1095 static inline void mousedev_psaux_unregister(void) { }
1096 #endif
1097 
1098 static int __init mousedev_init(void)
1099 {
1100 	int error;
1101 
1102 	mousedev_mix = mousedev_create(NULL, &mousedev_handler, true);
1103 	if (IS_ERR(mousedev_mix))
1104 		return PTR_ERR(mousedev_mix);
1105 
1106 	error = input_register_handler(&mousedev_handler);
1107 	if (error) {
1108 		mousedev_destroy(mousedev_mix);
1109 		return error;
1110 	}
1111 
1112 	mousedev_psaux_register();
1113 
1114 	pr_info("PS/2 mouse device common for all mice\n");
1115 
1116 	return 0;
1117 }
1118 
1119 static void __exit mousedev_exit(void)
1120 {
1121 	mousedev_psaux_unregister();
1122 	input_unregister_handler(&mousedev_handler);
1123 	mousedev_destroy(mousedev_mix);
1124 }
1125 
1126 module_init(mousedev_init);
1127 module_exit(mousedev_exit);
1128