xref: /openbmc/linux/drivers/input/joydev.c (revision 358a89ca)
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/module.h>
26 #include <linux/poll.h>
27 #include <linux/init.h>
28 #include <linux/device.h>
29 #include <linux/cdev.h>
30 
31 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
32 MODULE_DESCRIPTION("Joystick device interfaces");
33 MODULE_SUPPORTED_DEVICE("input/js");
34 MODULE_LICENSE("GPL");
35 
36 #define JOYDEV_MINOR_BASE	0
37 #define JOYDEV_MINORS		16
38 #define JOYDEV_BUFFER_SIZE	64
39 
40 struct joydev {
41 	int open;
42 	struct input_handle handle;
43 	wait_queue_head_t wait;
44 	struct list_head client_list;
45 	spinlock_t client_lock; /* protects client_list */
46 	struct mutex mutex;
47 	struct device dev;
48 	struct cdev cdev;
49 	bool exist;
50 
51 	struct js_corr corr[ABS_CNT];
52 	struct JS_DATA_SAVE_TYPE glue;
53 	int nabs;
54 	int nkey;
55 	__u16 keymap[KEY_MAX - BTN_MISC + 1];
56 	__u16 keypam[KEY_MAX - BTN_MISC + 1];
57 	__u8 absmap[ABS_CNT];
58 	__u8 abspam[ABS_CNT];
59 	__s16 abs[ABS_CNT];
60 };
61 
62 struct joydev_client {
63 	struct js_event buffer[JOYDEV_BUFFER_SIZE];
64 	int head;
65 	int tail;
66 	int startup;
67 	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
68 	struct fasync_struct *fasync;
69 	struct joydev *joydev;
70 	struct list_head node;
71 };
72 
73 static int joydev_correct(int value, struct js_corr *corr)
74 {
75 	switch (corr->type) {
76 
77 	case JS_CORR_NONE:
78 		break;
79 
80 	case JS_CORR_BROKEN:
81 		value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
82 			((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
83 			((corr->coef[2] * (value - corr->coef[0])) >> 14);
84 		break;
85 
86 	default:
87 		return 0;
88 	}
89 
90 	return clamp(value, -32767, 32767);
91 }
92 
93 static void joydev_pass_event(struct joydev_client *client,
94 			      struct js_event *event)
95 {
96 	struct joydev *joydev = client->joydev;
97 
98 	/*
99 	 * IRQs already disabled, just acquire the lock
100 	 */
101 	spin_lock(&client->buffer_lock);
102 
103 	client->buffer[client->head] = *event;
104 
105 	if (client->startup == joydev->nabs + joydev->nkey) {
106 		client->head++;
107 		client->head &= JOYDEV_BUFFER_SIZE - 1;
108 		if (client->tail == client->head)
109 			client->startup = 0;
110 	}
111 
112 	spin_unlock(&client->buffer_lock);
113 
114 	kill_fasync(&client->fasync, SIGIO, POLL_IN);
115 }
116 
117 static void joydev_event(struct input_handle *handle,
118 			 unsigned int type, unsigned int code, int value)
119 {
120 	struct joydev *joydev = handle->private;
121 	struct joydev_client *client;
122 	struct js_event event;
123 
124 	switch (type) {
125 
126 	case EV_KEY:
127 		if (code < BTN_MISC || value == 2)
128 			return;
129 		event.type = JS_EVENT_BUTTON;
130 		event.number = joydev->keymap[code - BTN_MISC];
131 		event.value = value;
132 		break;
133 
134 	case EV_ABS:
135 		event.type = JS_EVENT_AXIS;
136 		event.number = joydev->absmap[code];
137 		event.value = joydev_correct(value,
138 					&joydev->corr[event.number]);
139 		if (event.value == joydev->abs[event.number])
140 			return;
141 		joydev->abs[event.number] = event.value;
142 		break;
143 
144 	default:
145 		return;
146 	}
147 
148 	event.time = jiffies_to_msecs(jiffies);
149 
150 	rcu_read_lock();
151 	list_for_each_entry_rcu(client, &joydev->client_list, node)
152 		joydev_pass_event(client, &event);
153 	rcu_read_unlock();
154 
155 	wake_up_interruptible(&joydev->wait);
156 }
157 
158 static int joydev_fasync(int fd, struct file *file, int on)
159 {
160 	struct joydev_client *client = file->private_data;
161 
162 	return fasync_helper(fd, file, on, &client->fasync);
163 }
164 
165 static void joydev_free(struct device *dev)
166 {
167 	struct joydev *joydev = container_of(dev, struct joydev, dev);
168 
169 	input_put_device(joydev->handle.dev);
170 	kfree(joydev);
171 }
172 
173 static void joydev_attach_client(struct joydev *joydev,
174 				 struct joydev_client *client)
175 {
176 	spin_lock(&joydev->client_lock);
177 	list_add_tail_rcu(&client->node, &joydev->client_list);
178 	spin_unlock(&joydev->client_lock);
179 }
180 
181 static void joydev_detach_client(struct joydev *joydev,
182 				 struct joydev_client *client)
183 {
184 	spin_lock(&joydev->client_lock);
185 	list_del_rcu(&client->node);
186 	spin_unlock(&joydev->client_lock);
187 	synchronize_rcu();
188 }
189 
190 static void joydev_refresh_state(struct joydev *joydev)
191 {
192 	struct input_dev *dev = joydev->handle.dev;
193 	int i, val;
194 
195 	for (i = 0; i < joydev->nabs; i++) {
196 		val = input_abs_get_val(dev, joydev->abspam[i]);
197 		joydev->abs[i] = joydev_correct(val, &joydev->corr[i]);
198 	}
199 }
200 
201 static int joydev_open_device(struct joydev *joydev)
202 {
203 	int retval;
204 
205 	retval = mutex_lock_interruptible(&joydev->mutex);
206 	if (retval)
207 		return retval;
208 
209 	if (!joydev->exist)
210 		retval = -ENODEV;
211 	else if (!joydev->open++) {
212 		retval = input_open_device(&joydev->handle);
213 		if (retval)
214 			joydev->open--;
215 		else
216 			joydev_refresh_state(joydev);
217 	}
218 
219 	mutex_unlock(&joydev->mutex);
220 	return retval;
221 }
222 
223 static void joydev_close_device(struct joydev *joydev)
224 {
225 	mutex_lock(&joydev->mutex);
226 
227 	if (joydev->exist && !--joydev->open)
228 		input_close_device(&joydev->handle);
229 
230 	mutex_unlock(&joydev->mutex);
231 }
232 
233 /*
234  * Wake up users waiting for IO so they can disconnect from
235  * dead device.
236  */
237 static void joydev_hangup(struct joydev *joydev)
238 {
239 	struct joydev_client *client;
240 
241 	spin_lock(&joydev->client_lock);
242 	list_for_each_entry(client, &joydev->client_list, node)
243 		kill_fasync(&client->fasync, SIGIO, POLL_HUP);
244 	spin_unlock(&joydev->client_lock);
245 
246 	wake_up_interruptible(&joydev->wait);
247 }
248 
249 static int joydev_release(struct inode *inode, struct file *file)
250 {
251 	struct joydev_client *client = file->private_data;
252 	struct joydev *joydev = client->joydev;
253 
254 	joydev_detach_client(joydev, client);
255 	kfree(client);
256 
257 	joydev_close_device(joydev);
258 
259 	return 0;
260 }
261 
262 static int joydev_open(struct inode *inode, struct file *file)
263 {
264 	struct joydev *joydev =
265 			container_of(inode->i_cdev, struct joydev, cdev);
266 	struct joydev_client *client;
267 	int error;
268 
269 	client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
270 	if (!client)
271 		return -ENOMEM;
272 
273 	spin_lock_init(&client->buffer_lock);
274 	client->joydev = joydev;
275 	joydev_attach_client(joydev, client);
276 
277 	error = joydev_open_device(joydev);
278 	if (error)
279 		goto err_free_client;
280 
281 	file->private_data = client;
282 	nonseekable_open(inode, file);
283 
284 	return 0;
285 
286  err_free_client:
287 	joydev_detach_client(joydev, client);
288 	kfree(client);
289 	return error;
290 }
291 
292 static int joydev_generate_startup_event(struct joydev_client *client,
293 					 struct input_dev *input,
294 					 struct js_event *event)
295 {
296 	struct joydev *joydev = client->joydev;
297 	int have_event;
298 
299 	spin_lock_irq(&client->buffer_lock);
300 
301 	have_event = client->startup < joydev->nabs + joydev->nkey;
302 
303 	if (have_event) {
304 
305 		event->time = jiffies_to_msecs(jiffies);
306 		if (client->startup < joydev->nkey) {
307 			event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
308 			event->number = client->startup;
309 			event->value = !!test_bit(joydev->keypam[event->number],
310 						  input->key);
311 		} else {
312 			event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
313 			event->number = client->startup - joydev->nkey;
314 			event->value = joydev->abs[event->number];
315 		}
316 		client->startup++;
317 	}
318 
319 	spin_unlock_irq(&client->buffer_lock);
320 
321 	return have_event;
322 }
323 
324 static int joydev_fetch_next_event(struct joydev_client *client,
325 				   struct js_event *event)
326 {
327 	int have_event;
328 
329 	spin_lock_irq(&client->buffer_lock);
330 
331 	have_event = client->head != client->tail;
332 	if (have_event) {
333 		*event = client->buffer[client->tail++];
334 		client->tail &= JOYDEV_BUFFER_SIZE - 1;
335 	}
336 
337 	spin_unlock_irq(&client->buffer_lock);
338 
339 	return have_event;
340 }
341 
342 /*
343  * Old joystick interface
344  */
345 static ssize_t joydev_0x_read(struct joydev_client *client,
346 			      struct input_dev *input,
347 			      char __user *buf)
348 {
349 	struct joydev *joydev = client->joydev;
350 	struct JS_DATA_TYPE data;
351 	int i;
352 
353 	spin_lock_irq(&input->event_lock);
354 
355 	/*
356 	 * Get device state
357 	 */
358 	for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
359 		data.buttons |=
360 			test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
361 	data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
362 	data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
363 
364 	/*
365 	 * Reset reader's event queue
366 	 */
367 	spin_lock(&client->buffer_lock);
368 	client->startup = 0;
369 	client->tail = client->head;
370 	spin_unlock(&client->buffer_lock);
371 
372 	spin_unlock_irq(&input->event_lock);
373 
374 	if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
375 		return -EFAULT;
376 
377 	return sizeof(struct JS_DATA_TYPE);
378 }
379 
380 static inline int joydev_data_pending(struct joydev_client *client)
381 {
382 	struct joydev *joydev = client->joydev;
383 
384 	return client->startup < joydev->nabs + joydev->nkey ||
385 		client->head != client->tail;
386 }
387 
388 static ssize_t joydev_read(struct file *file, char __user *buf,
389 			   size_t count, loff_t *ppos)
390 {
391 	struct joydev_client *client = file->private_data;
392 	struct joydev *joydev = client->joydev;
393 	struct input_dev *input = joydev->handle.dev;
394 	struct js_event event;
395 	int retval;
396 
397 	if (!joydev->exist)
398 		return -ENODEV;
399 
400 	if (count < sizeof(struct js_event))
401 		return -EINVAL;
402 
403 	if (count == sizeof(struct JS_DATA_TYPE))
404 		return joydev_0x_read(client, input, buf);
405 
406 	if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
407 		return -EAGAIN;
408 
409 	retval = wait_event_interruptible(joydev->wait,
410 			!joydev->exist || joydev_data_pending(client));
411 	if (retval)
412 		return retval;
413 
414 	if (!joydev->exist)
415 		return -ENODEV;
416 
417 	while (retval + sizeof(struct js_event) <= count &&
418 	       joydev_generate_startup_event(client, input, &event)) {
419 
420 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
421 			return -EFAULT;
422 
423 		retval += sizeof(struct js_event);
424 	}
425 
426 	while (retval + sizeof(struct js_event) <= count &&
427 	       joydev_fetch_next_event(client, &event)) {
428 
429 		if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
430 			return -EFAULT;
431 
432 		retval += sizeof(struct js_event);
433 	}
434 
435 	return retval;
436 }
437 
438 /* No kernel lock - fine */
439 static unsigned int joydev_poll(struct file *file, poll_table *wait)
440 {
441 	struct joydev_client *client = file->private_data;
442 	struct joydev *joydev = client->joydev;
443 
444 	poll_wait(file, &joydev->wait, wait);
445 	return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
446 		(joydev->exist ?  0 : (POLLHUP | POLLERR));
447 }
448 
449 static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev,
450 				     void __user *argp, size_t len)
451 {
452 	__u8 *abspam;
453 	int i;
454 	int retval = 0;
455 
456 	len = min(len, sizeof(joydev->abspam));
457 
458 	/* Validate the map. */
459 	abspam = memdup_user(argp, len);
460 	if (IS_ERR(abspam))
461 		return PTR_ERR(abspam);
462 
463 	for (i = 0; i < joydev->nabs; i++) {
464 		if (abspam[i] > ABS_MAX) {
465 			retval = -EINVAL;
466 			goto out;
467 		}
468 	}
469 
470 	memcpy(joydev->abspam, abspam, len);
471 
472 	for (i = 0; i < joydev->nabs; i++)
473 		joydev->absmap[joydev->abspam[i]] = i;
474 
475  out:
476 	kfree(abspam);
477 	return retval;
478 }
479 
480 static int joydev_handle_JSIOCSBTNMAP(struct joydev *joydev,
481 				      void __user *argp, size_t len)
482 {
483 	__u16 *keypam;
484 	int i;
485 	int retval = 0;
486 
487 	len = min(len, sizeof(joydev->keypam));
488 
489 	/* Validate the map. */
490 	keypam = memdup_user(argp, len);
491 	if (IS_ERR(keypam))
492 		return PTR_ERR(keypam);
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 	/* joydev is marked dead so no one else accesses joydev->open */
746 	if (joydev->open)
747 		input_close_device(handle);
748 }
749 
750 static bool joydev_dev_is_absolute_mouse(struct input_dev *dev)
751 {
752 	DECLARE_BITMAP(jd_scratch, KEY_CNT);
753 
754 	BUILD_BUG_ON(ABS_CNT > KEY_CNT || EV_CNT > KEY_CNT);
755 
756 	/*
757 	 * Virtualization (VMware, etc) and remote management (HP
758 	 * ILO2) solutions use absolute coordinates for their virtual
759 	 * pointing devices so that there is one-to-one relationship
760 	 * between pointer position on the host screen and virtual
761 	 * guest screen, and so their mice use ABS_X, ABS_Y and 3
762 	 * primary button events. This clashes with what joydev
763 	 * considers to be joysticks (a device with at minimum ABS_X
764 	 * axis).
765 	 *
766 	 * Here we are trying to separate absolute mice from
767 	 * joysticks. A device is, for joystick detection purposes,
768 	 * considered to be an absolute mouse if the following is
769 	 * true:
770 	 *
771 	 * 1) Event types are exactly EV_ABS, EV_KEY and EV_SYN.
772 	 * 2) Absolute events are exactly ABS_X and ABS_Y.
773 	 * 3) Keys are exactly BTN_LEFT, BTN_RIGHT and BTN_MIDDLE.
774 	 * 4) Device is not on "Amiga" bus.
775 	 */
776 
777 	bitmap_zero(jd_scratch, EV_CNT);
778 	__set_bit(EV_ABS, jd_scratch);
779 	__set_bit(EV_KEY, jd_scratch);
780 	__set_bit(EV_SYN, jd_scratch);
781 	if (!bitmap_equal(jd_scratch, dev->evbit, EV_CNT))
782 		return false;
783 
784 	bitmap_zero(jd_scratch, ABS_CNT);
785 	__set_bit(ABS_X, jd_scratch);
786 	__set_bit(ABS_Y, jd_scratch);
787 	if (!bitmap_equal(dev->absbit, jd_scratch, ABS_CNT))
788 		return false;
789 
790 	bitmap_zero(jd_scratch, KEY_CNT);
791 	__set_bit(BTN_LEFT, jd_scratch);
792 	__set_bit(BTN_RIGHT, jd_scratch);
793 	__set_bit(BTN_MIDDLE, jd_scratch);
794 
795 	if (!bitmap_equal(dev->keybit, jd_scratch, KEY_CNT))
796 		return false;
797 
798 	/*
799 	 * Amiga joystick (amijoy) historically uses left/middle/right
800 	 * button events.
801 	 */
802 	if (dev->id.bustype == BUS_AMIGA)
803 		return false;
804 
805 	return true;
806 }
807 
808 static bool joydev_match(struct input_handler *handler, struct input_dev *dev)
809 {
810 	/* Avoid touchpads and touchscreens */
811 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_TOUCH, dev->keybit))
812 		return false;
813 
814 	/* Avoid tablets, digitisers and similar devices */
815 	if (test_bit(EV_KEY, dev->evbit) && test_bit(BTN_DIGI, dev->keybit))
816 		return false;
817 
818 	/* Avoid absolute mice */
819 	if (joydev_dev_is_absolute_mouse(dev))
820 		return false;
821 
822 	return true;
823 }
824 
825 static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
826 			  const struct input_device_id *id)
827 {
828 	struct joydev *joydev;
829 	int i, j, t, minor, dev_no;
830 	int error;
831 
832 	minor = input_get_new_minor(JOYDEV_MINOR_BASE, JOYDEV_MINORS, true);
833 	if (minor < 0) {
834 		error = minor;
835 		pr_err("failed to reserve new minor: %d\n", error);
836 		return error;
837 	}
838 
839 	joydev = kzalloc(sizeof(struct joydev), GFP_KERNEL);
840 	if (!joydev) {
841 		error = -ENOMEM;
842 		goto err_free_minor;
843 	}
844 
845 	INIT_LIST_HEAD(&joydev->client_list);
846 	spin_lock_init(&joydev->client_lock);
847 	mutex_init(&joydev->mutex);
848 	init_waitqueue_head(&joydev->wait);
849 	joydev->exist = true;
850 
851 	dev_no = minor;
852 	/* Normalize device number if it falls into legacy range */
853 	if (dev_no < JOYDEV_MINOR_BASE + JOYDEV_MINORS)
854 		dev_no -= JOYDEV_MINOR_BASE;
855 	dev_set_name(&joydev->dev, "js%d", dev_no);
856 
857 	joydev->handle.dev = input_get_device(dev);
858 	joydev->handle.name = dev_name(&joydev->dev);
859 	joydev->handle.handler = handler;
860 	joydev->handle.private = joydev;
861 
862 	for_each_set_bit(i, dev->absbit, ABS_CNT) {
863 		joydev->absmap[i] = joydev->nabs;
864 		joydev->abspam[joydev->nabs] = i;
865 		joydev->nabs++;
866 	}
867 
868 	for (i = BTN_JOYSTICK - BTN_MISC; i < KEY_MAX - BTN_MISC + 1; i++)
869 		if (test_bit(i + BTN_MISC, dev->keybit)) {
870 			joydev->keymap[i] = joydev->nkey;
871 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
872 			joydev->nkey++;
873 		}
874 
875 	for (i = 0; i < BTN_JOYSTICK - BTN_MISC; i++)
876 		if (test_bit(i + BTN_MISC, dev->keybit)) {
877 			joydev->keymap[i] = joydev->nkey;
878 			joydev->keypam[joydev->nkey] = i + BTN_MISC;
879 			joydev->nkey++;
880 		}
881 
882 	for (i = 0; i < joydev->nabs; i++) {
883 		j = joydev->abspam[i];
884 		if (input_abs_get_max(dev, j) == input_abs_get_min(dev, j)) {
885 			joydev->corr[i].type = JS_CORR_NONE;
886 			continue;
887 		}
888 		joydev->corr[i].type = JS_CORR_BROKEN;
889 		joydev->corr[i].prec = input_abs_get_fuzz(dev, j);
890 
891 		t = (input_abs_get_max(dev, j) + input_abs_get_min(dev, j)) / 2;
892 		joydev->corr[i].coef[0] = t - input_abs_get_flat(dev, j);
893 		joydev->corr[i].coef[1] = t + input_abs_get_flat(dev, j);
894 
895 		t = (input_abs_get_max(dev, j) - input_abs_get_min(dev, j)) / 2
896 			- 2 * input_abs_get_flat(dev, j);
897 		if (t) {
898 			joydev->corr[i].coef[2] = (1 << 29) / t;
899 			joydev->corr[i].coef[3] = (1 << 29) / t;
900 		}
901 	}
902 
903 	joydev->dev.devt = MKDEV(INPUT_MAJOR, minor);
904 	joydev->dev.class = &input_class;
905 	joydev->dev.parent = &dev->dev;
906 	joydev->dev.release = joydev_free;
907 	device_initialize(&joydev->dev);
908 
909 	error = input_register_handle(&joydev->handle);
910 	if (error)
911 		goto err_free_joydev;
912 
913 	cdev_init(&joydev->cdev, &joydev_fops);
914 
915 	error = cdev_device_add(&joydev->cdev, &joydev->dev);
916 	if (error)
917 		goto err_cleanup_joydev;
918 
919 	return 0;
920 
921  err_cleanup_joydev:
922 	joydev_cleanup(joydev);
923 	input_unregister_handle(&joydev->handle);
924  err_free_joydev:
925 	put_device(&joydev->dev);
926  err_free_minor:
927 	input_free_minor(minor);
928 	return error;
929 }
930 
931 static void joydev_disconnect(struct input_handle *handle)
932 {
933 	struct joydev *joydev = handle->private;
934 
935 	cdev_device_del(&joydev->cdev, &joydev->dev);
936 	joydev_cleanup(joydev);
937 	input_free_minor(MINOR(joydev->dev.devt));
938 	input_unregister_handle(handle);
939 	put_device(&joydev->dev);
940 }
941 
942 static const struct input_device_id joydev_ids[] = {
943 	{
944 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
945 				INPUT_DEVICE_ID_MATCH_ABSBIT,
946 		.evbit = { BIT_MASK(EV_ABS) },
947 		.absbit = { BIT_MASK(ABS_X) },
948 	},
949 	{
950 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
951 				INPUT_DEVICE_ID_MATCH_ABSBIT,
952 		.evbit = { BIT_MASK(EV_ABS) },
953 		.absbit = { BIT_MASK(ABS_Z) },
954 	},
955 	{
956 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
957 				INPUT_DEVICE_ID_MATCH_ABSBIT,
958 		.evbit = { BIT_MASK(EV_ABS) },
959 		.absbit = { BIT_MASK(ABS_WHEEL) },
960 	},
961 	{
962 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
963 				INPUT_DEVICE_ID_MATCH_ABSBIT,
964 		.evbit = { BIT_MASK(EV_ABS) },
965 		.absbit = { BIT_MASK(ABS_THROTTLE) },
966 	},
967 	{
968 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
969 				INPUT_DEVICE_ID_MATCH_KEYBIT,
970 		.evbit = { BIT_MASK(EV_KEY) },
971 		.keybit = {[BIT_WORD(BTN_JOYSTICK)] = BIT_MASK(BTN_JOYSTICK) },
972 	},
973 	{
974 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
975 				INPUT_DEVICE_ID_MATCH_KEYBIT,
976 		.evbit = { BIT_MASK(EV_KEY) },
977 		.keybit = { [BIT_WORD(BTN_GAMEPAD)] = BIT_MASK(BTN_GAMEPAD) },
978 	},
979 	{
980 		.flags = INPUT_DEVICE_ID_MATCH_EVBIT |
981 				INPUT_DEVICE_ID_MATCH_KEYBIT,
982 		.evbit = { BIT_MASK(EV_KEY) },
983 		.keybit = { [BIT_WORD(BTN_TRIGGER_HAPPY)] = BIT_MASK(BTN_TRIGGER_HAPPY) },
984 	},
985 	{ }	/* Terminating entry */
986 };
987 
988 MODULE_DEVICE_TABLE(input, joydev_ids);
989 
990 static struct input_handler joydev_handler = {
991 	.event		= joydev_event,
992 	.match		= joydev_match,
993 	.connect	= joydev_connect,
994 	.disconnect	= joydev_disconnect,
995 	.legacy_minors	= true,
996 	.minor		= JOYDEV_MINOR_BASE,
997 	.name		= "joydev",
998 	.id_table	= joydev_ids,
999 };
1000 
1001 static int __init joydev_init(void)
1002 {
1003 	return input_register_handler(&joydev_handler);
1004 }
1005 
1006 static void __exit joydev_exit(void)
1007 {
1008 	input_unregister_handler(&joydev_handler);
1009 }
1010 
1011 module_init(joydev_init);
1012 module_exit(joydev_exit);
1013