xref: /linux/drivers/input/joydev.c (revision 08ec212c0f92cbf30e3ecc7349f18151714041d6)
1 /*
2  * Joystick device driver for the input driver suite.
3  *
4  * Copyright (c) 1999-2002 Vojtech Pavlik
5  * Copyright (c) 1999 Colin Van Dyke
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 as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  */
12 
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <asm/io.h>
16 #include <linux/delay.h>
17 #include <linux/errno.h>
18 #include <linux/joystick.h>
19 #include <linux/input.h>
20 #include <linux/kernel.h>
21 #include <linux/major.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/mm.h>
25 #include <linux/miscdevice.h>
26 #include <linux/module.h>
27 #include <linux/poll.h>
28 #include <linux/init.h>
29 #include <linux/device.h>
30 #include <linux/cdev.h>
31 
32 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
33 MODULE_DESCRIPTION("Joystick device interfaces");
34 MODULE_SUPPORTED_DEVICE("input/js");
35 MODULE_LICENSE("GPL");
36 
37 #define JOYDEV_MINOR_BASE	0
38 #define JOYDEV_MINORS		16
39 #define JOYDEV_BUFFER_SIZE	64
40 
41 struct joydev {
42 	int open;
43 	struct input_handle handle;
44 	wait_queue_head_t wait;
45 	struct list_head client_list;
46 	spinlock_t client_lock; /* protects client_list */
47 	struct mutex mutex;
48 	struct device dev;
49 	struct cdev cdev;
50 	bool exist;
51 
52 	struct js_corr corr[ABS_CNT];
53 	struct JS_DATA_SAVE_TYPE glue;
54 	int nabs;
55 	int nkey;
56 	__u16 keymap[KEY_MAX - BTN_MISC + 1];
57 	__u16 keypam[KEY_MAX - BTN_MISC + 1];
58 	__u8 absmap[ABS_CNT];
59 	__u8 abspam[ABS_CNT];
60 	__s16 abs[ABS_CNT];
61 };
62 
63 struct joydev_client {
64 	struct js_event buffer[JOYDEV_BUFFER_SIZE];
65 	int head;
66 	int tail;
67 	int startup;
68 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
69 	struct fasync_struct *fasync;
70 	struct joydev *joydev;
71 	struct list_head node;
72 };
73 
74 static int joydev_correct(int value, struct js_corr *corr)
75 {
76 	switch (corr->type) {
77 
78 	case JS_CORR_NONE:
79 		break;
80 
81 	case JS_CORR_BROKEN:
82 		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
83 			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
84 			((corr->coef[2] * (value - corr->coef[0])) >> 14);
85 		break;
86 
87 	default:
88 		return 0;
89 	}
90 
91 	return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
92 }
93 
94 static void joydev_pass_event(struct joydev_client *client,
95 			      struct js_event *event)
96 {
97 	struct joydev *joydev = client->joydev;
98 
99 	/*
100 	 * IRQs already disabled, just acquire the lock
101 	 */
102 	spin_lock(&client->buffer_lock);
103 
104 	client->buffer[client->head] = *event;
105 
106 	if (client->startup == joydev->nabs + joydev->nkey) {
107 		client->head++;
108 		client->head &= JOYDEV_BUFFER_SIZE - 1;
109 		if (client->tail == client->head)
110 			client->startup = 0;
111 	}
112 
113 	spin_unlock(&client->buffer_lock);
114 
115 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
116 }
117 
118 static void joydev_event(struct input_handle *handle,
119 			 unsigned int type, unsigned int code, int value)
120 {
121 	struct joydev *joydev = handle->private;
122 	struct joydev_client *client;
123 	struct js_event event;
124 
125 	switch (type) {
126 
127 	case EV_KEY:
128 		if (code < BTN_MISC || value == 2)
129 			return;
130 		event.type = JS_EVENT_BUTTON;
131 		event.number = joydev->keymap[code - BTN_MISC];
132 		event.value = value;
133 		break;
134 
135 	case EV_ABS:
136 		event.type = JS_EVENT_AXIS;
137 		event.number = joydev->absmap[code];
138 		event.value = joydev_correct(value,
139 					&joydev->corr[event.number]);
140 		if (event.value == joydev->abs[event.number])
141 			return;
142 		joydev->abs[event.number] = event.value;
143 		break;
144 
145 	default:
146 		return;
147 	}
148 
149 	event.time = jiffies_to_msecs(jiffies);
150 
151 	rcu_read_lock();
152 	list_for_each_entry_rcu(client, &joydev->client_list, node)
153 		joydev_pass_event(client, &event);
154 	rcu_read_unlock();
155 
156 	wake_up_interruptible(&joydev->wait);
157 }
158 
159 static int joydev_fasync(int fd, struct file *file, int on)
160 {
161 	struct joydev_client *client = file->private_data;
162 
163 	return fasync_helper(fd, file, on, &client->fasync);
164 }
165 
166 static void joydev_free(struct device *dev)
167 {
168 	struct joydev *joydev = container_of(dev, struct joydev, dev);
169 
170 	input_put_device(joydev->handle.dev);
171 	kfree(joydev);
172 }
173 
174 static void joydev_attach_client(struct joydev *joydev,
175 				 struct joydev_client *client)
176 {
177 	spin_lock(&joydev->client_lock);
178 	list_add_tail_rcu(&client->node, &joydev->client_list);
179 	spin_unlock(&joydev->client_lock);
180 }
181 
182 static void joydev_detach_client(struct joydev *joydev,
183 				 struct joydev_client *client)
184 {
185 	spin_lock(&joydev->client_lock);
186 	list_del_rcu(&client->node);
187 	spin_unlock(&joydev->client_lock);
188 	synchronize_rcu();
189 }
190 
191 static int joydev_open_device(struct joydev *joydev)
192 {
193 	int retval;
194 
195 	retval = mutex_lock_interruptible(&joydev->mutex);
196 	if (retval)
197 		return retval;
198 
199 	if (!joydev->exist)
200 		retval = -ENODEV;
201 	else if (!joydev->open++) {
202 		retval = input_open_device(&joydev->handle);
203 		if (retval)
204 			joydev->open--;
205 	}
206 
207 	mutex_unlock(&joydev->mutex);
208 	return retval;
209 }
210 
211 static void joydev_close_device(struct joydev *joydev)
212 {
213 	mutex_lock(&joydev->mutex);
214 
215 	if (joydev->exist && !--joydev->open)
216 		input_close_device(&joydev->handle);
217 
218 	mutex_unlock(&joydev->mutex);
219 }
220 
221 /*
222  * Wake up users waiting for IO so they can disconnect from
223  * dead device.
224  */
225 static void joydev_hangup(struct joydev *joydev)
226 {
227 	struct joydev_client *client;
228 
229 	spin_lock(&joydev->client_lock);
230 	list_for_each_entry(client, &joydev->client_list, node)
231 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
232 	spin_unlock(&joydev->client_lock);
233 
234 	wake_up_interruptible(&joydev->wait);
235 }
236 
237 static int joydev_release(struct inode *inode, struct file *file)
238 {
239 	struct joydev_client *client = file->private_data;
240 	struct joydev *joydev = client->joydev;
241 
242 	joydev_detach_client(joydev, client);
243 	kfree(client);
244 
245 	joydev_close_device(joydev);
246 	put_device(&joydev->dev);
247 
248 	return 0;
249 }
250 
251 static int joydev_open(struct inode *inode, struct file *file)
252 {
253 	struct joydev *joydev =
254 			container_of(inode->i_cdev, struct joydev, cdev);
255 	struct joydev_client *client;
256 	int error;
257 
258 	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
259 	if (!client)
260 		return -ENOMEM;
261 
262 	spin_lock_init(&client->buffer_lock);
263 	client->joydev = joydev;
264 	joydev_attach_client(joydev, client);
265 
266 	error = joydev_open_device(joydev);
267 	if (error)
268 		goto err_free_client;
269 
270 	file->private_data = client;
271 	nonseekable_open(inode, file);
272 
273 	get_device(&joydev->dev);
274 	return 0;
275 
276  err_free_client:
277 	joydev_detach_client(joydev, client);
278 	kfree(client);
279 	return error;
280 }
281 
282 static int joydev_generate_startup_event(struct joydev_client *client,
283 					 struct input_dev *input,
284 					 struct js_event *event)
285 {
286 	struct joydev *joydev = client->joydev;
287 	int have_event;
288 
289 	spin_lock_irq(&client->buffer_lock);
290 
291 	have_event = client->startup < joydev->nabs + joydev->nkey;
292 
293 	if (have_event) {
294 
295 		event->time = jiffies_to_msecs(jiffies);
296 		if (client->startup < joydev->nkey) {
297 			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
298 			event->number = client->startup;
299 			event->value = !!test_bit(joydev->keypam[event->number],
300 						  input->key);
301 		} else {
302 			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
303 			event->number = client->startup - joydev->nkey;
304 			event->value = joydev->abs[event->number];
305 		}
306 		client->startup++;
307 	}
308 
309 	spin_unlock_irq(&client->buffer_lock);
310 
311 	return have_event;
312 }
313 
314 static int joydev_fetch_next_event(struct joydev_client *client,
315 				   struct js_event *event)
316 {
317 	int have_event;
318 
319 	spin_lock_irq(&client->buffer_lock);
320 
321 	have_event = client->head != client->tail;
322 	if (have_event) {
323 		*event = client->buffer[client->tail++];
324 		client->tail &= JOYDEV_BUFFER_SIZE - 1;
325 	}
326 
327 	spin_unlock_irq(&client->buffer_lock);
328 
329 	return have_event;
330 }
331 
332 /*
333  * Old joystick interface
334  */
335 static ssize_t joydev_0x_read(struct joydev_client *client,
336 			      struct input_dev *input,
337 			      char __user *buf)
338 {
339 	struct joydev *joydev = client->joydev;
340 	struct JS_DATA_TYPE data;
341 	int i;
342 
343 	spin_lock_irq(&input->event_lock);
344 
345 	/*
346 	 * Get device state
347 	 */
348 	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
349 		data.buttons |=
350 			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
351 	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
352 	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
353 
354 	/*
355 	 * Reset reader's event queue
356 	 */
357 	spin_lock(&client->buffer_lock);
358 	client->startup = 0;
359 	client->tail = client->head;
360 	spin_unlock(&client->buffer_lock);
361 
362 	spin_unlock_irq(&input->event_lock);
363 
364 	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
365 		return -EFAULT;
366 
367 	return sizeof(struct JS_DATA_TYPE);
368 }
369 
370 static inline int joydev_data_pending(struct joydev_client *client)
371 {
372 	struct joydev *joydev = client->joydev;
373 
374 	return client->startup < joydev->nabs + joydev->nkey ||
375 		client->head != client->tail;
376 }
377 
378 static ssize_t joydev_read(struct file *file, char __user *buf,
379 			   size_t count, loff_t *ppos)
380 {
381 	struct joydev_client *client = file->private_data;
382 	struct joydev *joydev = client->joydev;
383 	struct input_dev *input = joydev->handle.dev;
384 	struct js_event event;
385 	int retval;
386 
387 	if (!joydev->exist)
388 		return -ENODEV;
389 
390 	if (count < sizeof(struct js_event))
391 		return -EINVAL;
392 
393 	if (count == sizeof(struct JS_DATA_TYPE))
394 		return joydev_0x_read(client, input, buf);
395 
396 	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
397 		return -EAGAIN;
398 
399 	retval = wait_event_interruptible(joydev->wait,
400 			!joydev->exist || joydev_data_pending(client));
401 	if (retval)
402 		return retval;
403 
404 	if (!joydev->exist)
405 		return -ENODEV;
406 
407 	while (retval + sizeof(struct js_event) <= count &&
408 	       joydev_generate_startup_event(client, input, &event)) {
409 
410 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
411 			return -EFAULT;
412 
413 		retval += sizeof(struct js_event);
414 	}
415 
416 	while (retval + sizeof(struct js_event) <= count &&
417 	       joydev_fetch_next_event(client, &event)) {
418 
419 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
420 			return -EFAULT;
421 
422 		retval += sizeof(struct js_event);
423 	}
424 
425 	return retval;
426 }
427 
428 /* No kernel lock - fine */
429 static unsigned int joydev_poll(struct file *file, poll_table *wait)
430 {
431 	struct joydev_client *client = file->private_data;
432 	struct joydev *joydev = client->joydev;
433 
434 	poll_wait(file, &joydev->wait, wait);
435 	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
436 		(joydev->exist ?  0 : (POLLHUP | POLLERR));
437 }
438 
439 static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
440 				     void __user *argp, size_t len)
441 {
442 	__u8 *abspam;
443 	int i;
444 	int retval = 0;
445 
446 	len = min(len, sizeof(joydev->abspam));
447 
448 	/* Validate the map. */
449 	abspam = kmalloc(len, GFP_KERNEL);
450 	if (!abspam)
451 		return -ENOMEM;
452 
453 	if (copy_from_user(abspam, argp, len)) {
454 		retval = -EFAULT;
455 		goto out;
456 	}
457 
458 	for (i = 0; i < joydev->nabs; i++) {
459 		if (abspam[i] > ABS_MAX) {
460 			retval = -EINVAL;
461 			goto out;
462 		}
463 	}
464 
465 	memcpy(joydev->abspam, abspam, len);
466 
467 	for (i = 0; i < joydev->nabs; i++)
468 		joydev->absmap[joydev->abspam[i]] = i;
469 
470  out:
471 	kfree(abspam);
472 	return retval;
473 }
474 
475 static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
476 				      void __user *argp, size_t len)
477 {
478 	__u16 *keypam;
479 	int i;
480 	int retval = 0;
481 
482 	len = min(len, sizeof(joydev->keypam));
483 
484 	/* Validate the map. */
485 	keypam = kmalloc(len, GFP_KERNEL);
486 	if (!keypam)
487 		return -ENOMEM;
488 
489 	if (copy_from_user(keypam, argp, len)) {
490 		retval = -EFAULT;
491 		goto out;
492 	}
493 
494 	for (i = 0; i < joydev->nkey; i++) {
495 		if (keypam[i] > KEY_MAX || keypam[i] < BTN_MISC) {
496 			retval = -EINVAL;
497 			goto out;
498 		}
499 	}
500 
501 	memcpy(joydev->keypam, keypam, len);
502 
503 	for (i = 0; i < joydev->nkey; i++)
504 		joydev->keymap[keypam[i] - BTN_MISC] = i;
505 
506  out:
507 	kfree(keypam);
508 	return retval;
509 }
510 
511 
512 static int joydev_ioctl_common(struct joydev *joydev,
513 				unsigned int cmd, void __user *argp)
514 {
515 	struct input_dev *dev = joydev->handle.dev;
516 	size_t len;
517 	int i;
518 	const char *name;
519 
520 	/* Process fixed-sized commands. */
521 	switch (cmd) {
522 
523 	case JS_SET_CAL:
524 		return copy_from_user(&joydev->glue.JS_CORR, argp,
525 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
526 
527 	case JS_GET_CAL:
528 		return copy_to_user(argp, &joydev->glue.JS_CORR,
529 				sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;
530 
531 	case JS_SET_TIMEOUT:
532 		return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
533 
534 	case JS_GET_TIMEOUT:
535 		return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
536 
537 	case JSIOCGVERSION:
538 		return put_user(JS_VERSION, (__u32 __user *) argp);
539 
540 	case JSIOCGAXES:
541 		return put_user(joydev->nabs, (__u8 __user *) argp);
542 
543 	case JSIOCGBUTTONS:
544 		return put_user(joydev->nkey, (__u8 __user *) argp);
545 
546 	case JSIOCSCORR:
547 		if (copy_from_user(joydev->corr, argp,
548 			      sizeof(joydev->corr[0]) * joydev->nabs))
549 			return -EFAULT;
550 
551 		for (i = 0; i < joydev->nabs; i++) {
552 			int val = input_abs_get_val(dev, joydev->abspam[i]);
553 			joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);
554 		}
555 		return 0;
556 
557 	case JSIOCGCORR:
558 		return copy_to_user(argp, joydev->corr,
559 			sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
560 
561 	}
562 
563 	/*
564 	 * Process variable-sized commands (the axis and button map commands
565 	 * are considered variable-sized to decouple them from the values of
566 	 * ABS_MAX and KEY_MAX).
567 	 */
568 	switch (cmd & ~IOCSIZE_MASK) {
569 
570 	case (JSIOCSAXMAP & ~IOCSIZE_MASK):
571 		return joydev_handle_JSIOCSAXMAP(joydev, argp, _IOC_SIZE(cmd));
572 
573 	case (JSIOCGAXMAP & ~IOCSIZE_MASK):
574 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->abspam));
575 		return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : len;
576 
577 	case (JSIOCSBTNMAP & ~IOCSIZE_MASK):
578 		return joydev_handle_JSIOCSBTNMAP(joydev, argp, _IOC_SIZE(cmd));
579 
580 	case (JSIOCGBTNMAP & ~IOCSIZE_MASK):
581 		len = min_t(size_t, _IOC_SIZE(cmd), sizeof(joydev->keypam));
582 		return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : len;
583 
584 	case JSIOCGNAME(0):
585 		name = dev->name;
586 		if (!name)
587 			return 0;
588 
589 		len = min_t(size_t, _IOC_SIZE(cmd), strlen(name) + 1);
590 		return copy_to_user(argp, name, len) ? -EFAULT : len;
591 	}
592 
593 	return -EINVAL;
594 }
595 
596 #ifdef CONFIG_COMPAT
597 static long joydev_compat_ioctl(struct file *file,
598 				unsigned int cmd, unsigned long arg)
599 {
600 	struct joydev_client *client = file->private_data;
601 	struct joydev *joydev = client->joydev;
602 	void __user *argp = (void __user *)arg;
603 	s32 tmp32;
604 	struct JS_DATA_SAVE_TYPE_32 ds32;
605 	int retval;
606 
607 	retval = mutex_lock_interruptible(&joydev->mutex);
608 	if (retval)
609 		return retval;
610 
611 	if (!joydev->exist) {
612 		retval = -ENODEV;
613 		goto out;
614 	}
615 
616 	switch (cmd) {
617 
618 	case JS_SET_TIMELIMIT:
619 		retval = get_user(tmp32, (s32 __user *) arg);
620 		if (retval == 0)
621 			joydev->glue.JS_TIMELIMIT = tmp32;
622 		break;
623 
624 	case JS_GET_TIMELIMIT:
625 		tmp32 = joydev->glue.JS_TIMELIMIT;
626 		retval = put_user(tmp32, (s32 __user *) arg);
627 		break;
628 
629 	case JS_SET_ALL:
630 		retval = copy_from_user(&ds32, argp,
631 					sizeof(ds32)) ? -EFAULT : 0;
632 		if (retval == 0) {
633 			joydev->glue.JS_TIMEOUT    = ds32.JS_TIMEOUT;
634 			joydev->glue.BUSY          = ds32.BUSY;
635 			joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
636 			joydev->glue.JS_TIMELIMIT  = ds32.JS_TIMELIMIT;
637 			joydev->glue.JS_SAVE       = ds32.JS_SAVE;
638 			joydev->glue.JS_CORR       = ds32.JS_CORR;
639 		}
640 		break;
641 
642 	case JS_GET_ALL:
643 		ds32.JS_TIMEOUT    = joydev->glue.JS_TIMEOUT;
644 		ds32.BUSY          = joydev->glue.BUSY;
645 		ds32.JS_EXPIRETIME = joydev->glue.JS_EXPIRETIME;
646 		ds32.JS_TIMELIMIT  = joydev->glue.JS_TIMELIMIT;
647 		ds32.JS_SAVE       = joydev->glue.JS_SAVE;
648 		ds32.JS_CORR       = joydev->glue.JS_CORR;
649 
650 		retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
651 		break;
652 
653 	default:
654 		retval = joydev_ioctl_common(joydev, cmd, argp);
655 		break;
656 	}
657 
658  out:
659 	mutex_unlock(&joydev->mutex);
660 	return retval;
661 }
662 #endif /* CONFIG_COMPAT */
663 
664 static long joydev_ioctl(struct file *file,
665 			 unsigned int cmd, unsigned long arg)
666 {
667 	struct joydev_client *client = file->private_data;
668 	struct joydev *joydev = client->joydev;
669 	void __user *argp = (void __user *)arg;
670 	int retval;
671 
672 	retval = mutex_lock_interruptible(&joydev->mutex);
673 	if (retval)
674 		return retval;
675 
676 	if (!joydev->exist) {
677 		retval = -ENODEV;
678 		goto out;
679 	}
680 
681 	switch (cmd) {
682 
683 	case JS_SET_TIMELIMIT:
684 		retval = get_user(joydev->glue.JS_TIMELIMIT,
685 				  (long __user *) arg);
686 		break;
687 
688 	case JS_GET_TIMELIMIT:
689 		retval = put_user(joydev->glue.JS_TIMELIMIT,
690 				  (long __user *) arg);
691 		break;
692 
693 	case JS_SET_ALL:
694 		retval = copy_from_user(&joydev->glue, argp,
695 					sizeof(joydev->glue)) ? -EFAULT : 0;
696 		break;
697 
698 	case JS_GET_ALL:
699 		retval = copy_to_user(argp, &joydev->glue,
700 				      sizeof(joydev->glue)) ? -EFAULT : 0;
701 		break;
702 
703 	default:
704 		retval = joydev_ioctl_common(joydev, cmd, argp);
705 		break;
706 	}
707  out:
708 	mutex_unlock(&joydev->mutex);
709 	return retval;
710 }
711 
712 static const struct file_operations joydev_fops = {
713 	.owner		= THIS_MODULE,
714 	.read		= joydev_read,
715 	.poll		= joydev_poll,
716 	.open		= joydev_open,
717 	.release	= joydev_release,
718 	.unlocked_ioctl	= joydev_ioctl,
719 #ifdef CONFIG_COMPAT
720 	.compat_ioctl	= joydev_compat_ioctl,
721 #endif
722 	.fasync		= joydev_fasync,
723 	.llseek		= no_llseek,
724 };
725 
726 /*
727  * Mark device non-existent. This disables writes, ioctls and
728  * prevents new users from opening the device. Already posted
729  * blocking reads will stay, however new ones will fail.
730  */
731 static void joydev_mark_dead(struct joydev *joydev)
732 {
733 	mutex_lock(&joydev->mutex);
734 	joydev->exist = false;
735 	mutex_unlock(&joydev->mutex);
736 }
737 
738 static void joydev_cleanup(struct joydev *joydev)
739 {
740 	struct input_handle *handle = &joydev->handle;
741 
742 	joydev_mark_dead(joydev);
743 	joydev_hangup(joydev);
744 
745 	cdev_del(&joydev->cdev);
746 
747 	/* joydev is marked dead so no one else accesses joydev->open */
748 	if (joydev->open)
749 		input_close_device(handle);
750 }
751 
752 
753 static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
754 {
755 	/* Avoid touchpads and touchscreens */
756 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_TOUCH, dev->keybit))
757 		return false;
758 
759 	/* Avoid tablets, digitisers and similar devices */
760 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_DIGI, dev->keybit))
761 		return false;
762 
763 	return true;
764 }
765 
766 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
767 			  const struct input_device_id *id)
768 {
769 	struct joydev *joydev;
770 	int i, j, t, minor, dev_no;
771 	int error;
772 
773 	minor = input_get_new_minor(JOYDEV_MINOR_BASE, JOYDEV_MINORS, true);
774 	if (minor < 0) {
775 		error = minor;
776 		pr_err("failed to reserve new minor: %d\n", error);
777 		return error;
778 	}
779 
780 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
781 	if (!joydev) {
782 		error = -ENOMEM;
783 		goto err_free_minor;
784 	}
785 
786 	INIT_LIST_HEAD(&joydev->client_list);
787 	spin_lock_init(&joydev->client_lock);
788 	mutex_init(&joydev->mutex);
789 	init_waitqueue_head(&joydev->wait);
790 	joydev->exist = true;
791 
792 	dev_no = minor;
793 	/* Normalize device number if it falls into legacy range */
794 	if (dev_no < JOYDEV_MINOR_BASE + JOYDEV_MINORS)
795 		dev_no -= JOYDEV_MINOR_BASE;
796 	dev_set_name(&joydev->dev, "js%d", dev_no);
797 
798 	joydev->handle.dev = input_get_device(dev);
799 	joydev->handle.name = dev_name(&joydev->dev);
800 	joydev->handle.handler = handler;
801 	joydev->handle.private = joydev;
802 
803 	for (i = 0; i < ABS_CNT; i++)
804 		if (test_bit(i, dev->absbit)) {
805 			joydev->absmap[i] = joydev->nabs;
806 			joydev->abspam[joydev->nabs] = i;
807 			joydev->nabs++;
808 		}
809 
810 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
811 		if (test_bit(i + BTN_MISC, dev->keybit)) {
812 			joydev->keymap[i] = joydev->nkey;
813 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
814 			joydev->nkey++;
815 		}
816 
817 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
818 		if (test_bit(i + BTN_MISC, dev->keybit)) {
819 			joydev->keymap[i] = joydev->nkey;
820 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
821 			joydev->nkey++;
822 		}
823 
824 	for (i = 0; i < joydev->nabs; i++) {
825 		j = joydev->abspam[i];
826 		if (input_abs_get_max(dev, j) == input_abs_get_min(dev, j)) {
827 			joydev->corr[i].type = JS_CORR_NONE;
828 			joydev->abs[i] = input_abs_get_val(dev, j);
829 			continue;
830 		}
831 		joydev->corr[i].type = JS_CORR_BROKEN;
832 		joydev->corr[i].prec = input_abs_get_fuzz(dev, j);
833 
834 		t = (input_abs_get_max(dev, j) + input_abs_get_min(dev, j)) / 2;
835 		joydev->corr[i].coef[0] = t - input_abs_get_flat(dev, j);
836 		joydev->corr[i].coef[1] = t + input_abs_get_flat(dev, j);
837 
838 		t = (input_abs_get_max(dev, j) - input_abs_get_min(dev, j)) / 2
839 			- 2 * input_abs_get_flat(dev, j);
840 		if (t) {
841 			joydev->corr[i].coef[2] = (1 << 29) / t;
842 			joydev->corr[i].coef[3] = (1 << 29) / t;
843 
844 			joydev->abs[i] =
845 				joydev_correct(input_abs_get_val(dev, j),
846 					       joydev->corr + i);
847 		}
848 	}
849 
850 	joydev->dev.devt = MKDEV(INPUT_MAJOR, minor);
851 	joydev->dev.class = &input_class;
852 	joydev->dev.parent = &dev->dev;
853 	joydev->dev.release = joydev_free;
854 	device_initialize(&joydev->dev);
855 
856 	error = input_register_handle(&joydev->handle);
857 	if (error)
858 		goto err_free_joydev;
859 
860 	cdev_init(&joydev->cdev, &joydev_fops);
861 	error = cdev_add(&joydev->cdev, joydev->dev.devt, 1);
862 	if (error)
863 		goto err_unregister_handle;
864 
865 	error = device_add(&joydev->dev);
866 	if (error)
867 		goto err_cleanup_joydev;
868 
869 	return 0;
870 
871  err_cleanup_joydev:
872 	joydev_cleanup(joydev);
873  err_unregister_handle:
874 	input_unregister_handle(&joydev->handle);
875  err_free_joydev:
876 	put_device(&joydev->dev);
877  err_free_minor:
878 	input_free_minor(minor);
879 	return error;
880 }
881 
882 static void joydev_disconnect(struct input_handle *handle)
883 {
884 	struct joydev *joydev = handle->private;
885 
886 	device_del(&joydev->dev);
887 	joydev_cleanup(joydev);
888 	input_free_minor(MINOR(joydev->dev.devt));
889 	input_unregister_handle(handle);
890 	put_device(&joydev->dev);
891 }
892 
893 static const struct input_device_id joydev_ids[] = {
894 	{
895 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
896 				INPUT_DEVICE_ID_MATCH_ABSBIT,
897 		.evbit = { BIT_MASK(EV_ABS) },
898 		.absbit = { BIT_MASK(ABS_X) },
899 	},
900 	{
901 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
902 				INPUT_DEVICE_ID_MATCH_ABSBIT,
903 		.evbit = { BIT_MASK(EV_ABS) },
904 		.absbit = { BIT_MASK(ABS_WHEEL) },
905 	},
906 	{
907 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
908 				INPUT_DEVICE_ID_MATCH_ABSBIT,
909 		.evbit = { BIT_MASK(EV_ABS) },
910 		.absbit = { BIT_MASK(ABS_THROTTLE) },
911 	},
912 	{
913 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
914 				INPUT_DEVICE_ID_MATCH_KEYBIT,
915 		.evbit = { BIT_MASK(EV_KEY) },
916 		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
917 	},
918 	{
919 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
920 				INPUT_DEVICE_ID_MATCH_KEYBIT,
921 		.evbit = { BIT_MASK(EV_KEY) },
922 		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
923 	},
924 	{
925 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
926 				INPUT_DEVICE_ID_MATCH_KEYBIT,
927 		.evbit = { BIT_MASK(EV_KEY) },
928 		.keybit = { [BIT_WORD(BTN_TRIGGER_HAPPY)] = BIT_MASK(BTN_TRIGGER_HAPPY) },
929 	},
930 	{ }	/* Terminating entry */
931 };
932 
933 MODULE_DEVICE_TABLE(input, joydev_ids);
934 
935 static struct input_handler joydev_handler = {
936 	.event		= joydev_event,
937 	.match		= joydev_match,
938 	.connect	= joydev_connect,
939 	.disconnect	= joydev_disconnect,
940 	.legacy_minors	= true,
941 	.minor		= JOYDEV_MINOR_BASE,
942 	.name		= "joydev",
943 	.id_table	= joydev_ids,
944 };
945 
946 static int __init joydev_init(void)
947 {
948 	return input_register_handler(&joydev_handler);
949 }
950 
951 static void __exit joydev_exit(void)
952 {
953 	input_unregister_handler(&joydev_handler);
954 }
955 
956 module_init(joydev_init);
957 module_exit(joydev_exit);
958