1 /*
2  * LIRC base driver
3  *
4  * by Artur Lipowski <alipowski@interia.pl>
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  *
20  */
21 
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/sched.h>
25 #include <linux/errno.h>
26 #include <linux/ioctl.h>
27 #include <linux/fs.h>
28 #include <linux/poll.h>
29 #include <linux/completion.h>
30 #include <linux/mutex.h>
31 #include <linux/wait.h>
32 #include <linux/unistd.h>
33 #include <linux/kthread.h>
34 #include <linux/bitops.h>
35 #include <linux/device.h>
36 #include <linux/cdev.h>
37 
38 #include <media/lirc.h>
39 #include <media/lirc_dev.h>
40 
41 static bool debug;
42 
43 #define IRCTL_DEV_NAME	"BaseRemoteCtl"
44 #define NOPLUG		-1
45 #define LOGHEAD		"lirc_dev (%s[%d]): "
46 
47 static dev_t lirc_base_dev;
48 
49 struct irctl {
50 	struct lirc_driver d;
51 	int attached;
52 	int open;
53 
54 	struct mutex irctl_lock;
55 	struct lirc_buffer *buf;
56 	unsigned int chunk_size;
57 
58 	struct cdev *cdev;
59 
60 	struct task_struct *task;
61 	long jiffies_to_wait;
62 };
63 
64 static DEFINE_MUTEX(lirc_dev_lock);
65 
66 static struct irctl *irctls[MAX_IRCTL_DEVICES];
67 
68 /* Only used for sysfs but defined to void otherwise */
69 static struct class *lirc_class;
70 
71 /*  helper function
72  *  initializes the irctl structure
73  */
lirc_irctl_init(struct irctl * ir)74 static void lirc_irctl_init(struct irctl *ir)
75 {
76 	mutex_init(&ir->irctl_lock);
77 	ir->d.minor = NOPLUG;
78 }
79 
lirc_irctl_cleanup(struct irctl * ir)80 static void lirc_irctl_cleanup(struct irctl *ir)
81 {
82 	dev_dbg(ir->d.dev, LOGHEAD "cleaning up\n", ir->d.name, ir->d.minor);
83 
84 	device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
85 
86 	if (ir->buf != ir->d.rbuf) {
87 		lirc_buffer_free(ir->buf);
88 		kfree(ir->buf);
89 	}
90 	ir->buf = NULL;
91 }
92 
93 /*  helper function
94  *  reads key codes from driver and puts them into buffer
95  *  returns 0 on success
96  */
lirc_add_to_buf(struct irctl * ir)97 static int lirc_add_to_buf(struct irctl *ir)
98 {
99 	if (ir->d.add_to_buf) {
100 		int res = -ENODATA;
101 		int got_data = 0;
102 
103 		/*
104 		 * service the device as long as it is returning
105 		 * data and we have space
106 		 */
107 get_data:
108 		res = ir->d.add_to_buf(ir->d.data, ir->buf);
109 		if (res == 0) {
110 			got_data++;
111 			goto get_data;
112 		}
113 
114 		if (res == -ENODEV)
115 			kthread_stop(ir->task);
116 
117 		return got_data ? 0 : res;
118 	}
119 
120 	return 0;
121 }
122 
123 /* main function of the polling thread
124  */
lirc_thread(void * irctl)125 static int lirc_thread(void *irctl)
126 {
127 	struct irctl *ir = irctl;
128 
129 	dev_dbg(ir->d.dev, LOGHEAD "poll thread started\n",
130 		ir->d.name, ir->d.minor);
131 
132 	do {
133 		if (ir->open) {
134 			if (ir->jiffies_to_wait) {
135 				set_current_state(TASK_INTERRUPTIBLE);
136 				schedule_timeout(ir->jiffies_to_wait);
137 			}
138 			if (kthread_should_stop())
139 				break;
140 			if (!lirc_add_to_buf(ir))
141 				wake_up_interruptible(&ir->buf->wait_poll);
142 		} else {
143 			set_current_state(TASK_INTERRUPTIBLE);
144 			schedule();
145 		}
146 	} while (!kthread_should_stop());
147 
148 	dev_dbg(ir->d.dev, LOGHEAD "poll thread ended\n",
149 		ir->d.name, ir->d.minor);
150 
151 	return 0;
152 }
153 
154 
155 static struct file_operations lirc_dev_fops = {
156 	.owner		= THIS_MODULE,
157 	.read		= lirc_dev_fop_read,
158 	.write		= lirc_dev_fop_write,
159 	.poll		= lirc_dev_fop_poll,
160 	.unlocked_ioctl	= lirc_dev_fop_ioctl,
161 #ifdef CONFIG_COMPAT
162 	.compat_ioctl	= lirc_dev_fop_ioctl,
163 #endif
164 	.open		= lirc_dev_fop_open,
165 	.release	= lirc_dev_fop_close,
166 	.llseek		= noop_llseek,
167 };
168 
lirc_cdev_add(struct irctl * ir)169 static int lirc_cdev_add(struct irctl *ir)
170 {
171 	int retval = -ENOMEM;
172 	struct lirc_driver *d = &ir->d;
173 	struct cdev *cdev;
174 
175 	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
176 	if (!cdev)
177 		goto err_out;
178 
179 	if (d->fops) {
180 		cdev_init(cdev, d->fops);
181 		cdev->owner = d->owner;
182 	} else {
183 		cdev_init(cdev, &lirc_dev_fops);
184 		cdev->owner = THIS_MODULE;
185 	}
186 	retval = kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
187 	if (retval)
188 		goto err_out;
189 
190 	retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
191 	if (retval) {
192 		kobject_put(&cdev->kobj);
193 		goto err_out;
194 	}
195 
196 	ir->cdev = cdev;
197 
198 	return 0;
199 
200 err_out:
201 	kfree(cdev);
202 	return retval;
203 }
204 
lirc_register_driver(struct lirc_driver * d)205 int lirc_register_driver(struct lirc_driver *d)
206 {
207 	struct irctl *ir;
208 	int minor;
209 	int bytes_in_key;
210 	unsigned int chunk_size;
211 	unsigned int buffer_size;
212 	int err;
213 
214 	if (!d) {
215 		printk(KERN_ERR "lirc_dev: lirc_register_driver: "
216 		       "driver pointer must be not NULL!\n");
217 		err = -EBADRQC;
218 		goto out;
219 	}
220 
221 	if (!d->dev) {
222 		printk(KERN_ERR "%s: dev pointer not filled in!\n", __func__);
223 		err = -EINVAL;
224 		goto out;
225 	}
226 
227 	if (MAX_IRCTL_DEVICES <= d->minor) {
228 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
229 			"\"minor\" must be between 0 and %d (%d)!\n",
230 			MAX_IRCTL_DEVICES - 1, d->minor);
231 		err = -EBADRQC;
232 		goto out;
233 	}
234 
235 	if (1 > d->code_length || (BUFLEN * 8) < d->code_length) {
236 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
237 			"code length in bits for minor (%d) "
238 			"must be less than %d!\n",
239 			d->minor, BUFLEN * 8);
240 		err = -EBADRQC;
241 		goto out;
242 	}
243 
244 	dev_dbg(d->dev, "lirc_dev: lirc_register_driver: sample_rate: %d\n",
245 		d->sample_rate);
246 	if (d->sample_rate) {
247 		if (2 > d->sample_rate || HZ < d->sample_rate) {
248 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
249 				"sample_rate must be between 2 and %d!\n", HZ);
250 			err = -EBADRQC;
251 			goto out;
252 		}
253 		if (!d->add_to_buf) {
254 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
255 				"add_to_buf cannot be NULL when "
256 				"sample_rate is set\n");
257 			err = -EBADRQC;
258 			goto out;
259 		}
260 	} else if (!(d->fops && d->fops->read) && !d->rbuf) {
261 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
262 			"fops->read and rbuf cannot all be NULL!\n");
263 		err = -EBADRQC;
264 		goto out;
265 	} else if (!d->rbuf) {
266 		if (!(d->fops && d->fops->read && d->fops->poll &&
267 		      d->fops->unlocked_ioctl)) {
268 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
269 				"neither read, poll nor unlocked_ioctl can be NULL!\n");
270 			err = -EBADRQC;
271 			goto out;
272 		}
273 	}
274 
275 	mutex_lock(&lirc_dev_lock);
276 
277 	minor = d->minor;
278 
279 	if (minor < 0) {
280 		/* find first free slot for driver */
281 		for (minor = 0; minor < MAX_IRCTL_DEVICES; minor++)
282 			if (!irctls[minor])
283 				break;
284 		if (MAX_IRCTL_DEVICES == minor) {
285 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
286 				"no free slots for drivers!\n");
287 			err = -ENOMEM;
288 			goto out_lock;
289 		}
290 	} else if (irctls[minor]) {
291 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
292 			"minor (%d) just registered!\n", minor);
293 		err = -EBUSY;
294 		goto out_lock;
295 	}
296 
297 	ir = kzalloc(sizeof(struct irctl), GFP_KERNEL);
298 	if (!ir) {
299 		err = -ENOMEM;
300 		goto out_lock;
301 	}
302 	lirc_irctl_init(ir);
303 	irctls[minor] = ir;
304 	d->minor = minor;
305 
306 	if (d->sample_rate) {
307 		ir->jiffies_to_wait = HZ / d->sample_rate;
308 	} else {
309 		/* it means - wait for external event in task queue */
310 		ir->jiffies_to_wait = 0;
311 	}
312 
313 	/* some safety check 8-) */
314 	d->name[sizeof(d->name)-1] = '\0';
315 
316 	bytes_in_key = BITS_TO_LONGS(d->code_length) +
317 			(d->code_length % 8 ? 1 : 0);
318 	buffer_size = d->buffer_size ? d->buffer_size : BUFLEN / bytes_in_key;
319 	chunk_size  = d->chunk_size  ? d->chunk_size  : bytes_in_key;
320 
321 	if (d->rbuf) {
322 		ir->buf = d->rbuf;
323 	} else {
324 		ir->buf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
325 		if (!ir->buf) {
326 			err = -ENOMEM;
327 			goto out_lock;
328 		}
329 		err = lirc_buffer_init(ir->buf, chunk_size, buffer_size);
330 		if (err) {
331 			kfree(ir->buf);
332 			goto out_lock;
333 		}
334 	}
335 	ir->chunk_size = ir->buf->chunk_size;
336 
337 	if (d->features == 0)
338 		d->features = LIRC_CAN_REC_LIRCCODE;
339 
340 	ir->d = *d;
341 
342 	device_create(lirc_class, ir->d.dev,
343 		      MKDEV(MAJOR(lirc_base_dev), ir->d.minor), NULL,
344 		      "lirc%u", ir->d.minor);
345 
346 	if (d->sample_rate) {
347 		/* try to fire up polling thread */
348 		ir->task = kthread_run(lirc_thread, (void *)ir, "lirc_dev");
349 		if (IS_ERR(ir->task)) {
350 			dev_err(d->dev, "lirc_dev: lirc_register_driver: "
351 				"cannot run poll thread for minor = %d\n",
352 				d->minor);
353 			err = -ECHILD;
354 			goto out_sysfs;
355 		}
356 	}
357 
358 	err = lirc_cdev_add(ir);
359 	if (err)
360 		goto out_sysfs;
361 
362 	ir->attached = 1;
363 	mutex_unlock(&lirc_dev_lock);
364 
365 	dev_info(ir->d.dev, "lirc_dev: driver %s registered at minor = %d\n",
366 		 ir->d.name, ir->d.minor);
367 	return minor;
368 
369 out_sysfs:
370 	device_destroy(lirc_class, MKDEV(MAJOR(lirc_base_dev), ir->d.minor));
371 out_lock:
372 	mutex_unlock(&lirc_dev_lock);
373 out:
374 	return err;
375 }
376 EXPORT_SYMBOL(lirc_register_driver);
377 
lirc_unregister_driver(int minor)378 int lirc_unregister_driver(int minor)
379 {
380 	struct irctl *ir;
381 	struct cdev *cdev;
382 
383 	if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
384 		printk(KERN_ERR "lirc_dev: %s: minor (%d) must be between "
385 		       "0 and %d!\n", __func__, minor, MAX_IRCTL_DEVICES - 1);
386 		return -EBADRQC;
387 	}
388 
389 	ir = irctls[minor];
390 	if (!ir) {
391 		printk(KERN_ERR "lirc_dev: %s: failed to get irctl struct "
392 		       "for minor %d!\n", __func__, minor);
393 		return -ENOENT;
394 	}
395 
396 	cdev = ir->cdev;
397 
398 	mutex_lock(&lirc_dev_lock);
399 
400 	if (ir->d.minor != minor) {
401 		printk(KERN_ERR "lirc_dev: %s: minor (%d) device not "
402 		       "registered!\n", __func__, minor);
403 		mutex_unlock(&lirc_dev_lock);
404 		return -ENOENT;
405 	}
406 
407 	/* end up polling thread */
408 	if (ir->task)
409 		kthread_stop(ir->task);
410 
411 	dev_dbg(ir->d.dev, "lirc_dev: driver %s unregistered from minor = %d\n",
412 		ir->d.name, ir->d.minor);
413 
414 	ir->attached = 0;
415 	if (ir->open) {
416 		dev_dbg(ir->d.dev, LOGHEAD "releasing opened driver\n",
417 			ir->d.name, ir->d.minor);
418 		wake_up_interruptible(&ir->buf->wait_poll);
419 		mutex_lock(&ir->irctl_lock);
420 		ir->d.set_use_dec(ir->d.data);
421 		module_put(cdev->owner);
422 		mutex_unlock(&ir->irctl_lock);
423 	} else {
424 		lirc_irctl_cleanup(ir);
425 		cdev_del(cdev);
426 		kfree(cdev);
427 		kfree(ir);
428 		irctls[minor] = NULL;
429 	}
430 
431 	mutex_unlock(&lirc_dev_lock);
432 
433 	return 0;
434 }
435 EXPORT_SYMBOL(lirc_unregister_driver);
436 
lirc_dev_fop_open(struct inode * inode,struct file * file)437 int lirc_dev_fop_open(struct inode *inode, struct file *file)
438 {
439 	struct irctl *ir;
440 	struct cdev *cdev;
441 	int retval = 0;
442 
443 	if (iminor(inode) >= MAX_IRCTL_DEVICES) {
444 		printk(KERN_WARNING "lirc_dev [%d]: open result = -ENODEV\n",
445 		       iminor(inode));
446 		return -ENODEV;
447 	}
448 
449 	if (mutex_lock_interruptible(&lirc_dev_lock))
450 		return -ERESTARTSYS;
451 
452 	ir = irctls[iminor(inode)];
453 	if (!ir) {
454 		retval = -ENODEV;
455 		goto error;
456 	}
457 
458 	dev_dbg(ir->d.dev, LOGHEAD "open called\n", ir->d.name, ir->d.minor);
459 
460 	if (ir->d.minor == NOPLUG) {
461 		retval = -ENODEV;
462 		goto error;
463 	}
464 
465 	if (ir->open) {
466 		retval = -EBUSY;
467 		goto error;
468 	}
469 
470 	cdev = ir->cdev;
471 	if (try_module_get(cdev->owner)) {
472 		ir->open++;
473 		retval = ir->d.set_use_inc(ir->d.data);
474 
475 		if (retval) {
476 			module_put(cdev->owner);
477 			ir->open--;
478 		} else {
479 			lirc_buffer_clear(ir->buf);
480 		}
481 		if (ir->task)
482 			wake_up_process(ir->task);
483 	}
484 
485 error:
486 	if (ir)
487 		dev_dbg(ir->d.dev, LOGHEAD "open result = %d\n",
488 			ir->d.name, ir->d.minor, retval);
489 
490 	mutex_unlock(&lirc_dev_lock);
491 
492 	nonseekable_open(inode, file);
493 
494 	return retval;
495 }
496 EXPORT_SYMBOL(lirc_dev_fop_open);
497 
lirc_dev_fop_close(struct inode * inode,struct file * file)498 int lirc_dev_fop_close(struct inode *inode, struct file *file)
499 {
500 	struct irctl *ir = irctls[iminor(inode)];
501 	struct cdev *cdev;
502 
503 	if (!ir) {
504 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
505 		return -EINVAL;
506 	}
507 
508 	cdev = ir->cdev;
509 
510 	dev_dbg(ir->d.dev, LOGHEAD "close called\n", ir->d.name, ir->d.minor);
511 
512 	WARN_ON(mutex_lock_killable(&lirc_dev_lock));
513 
514 	ir->open--;
515 	if (ir->attached) {
516 		ir->d.set_use_dec(ir->d.data);
517 		module_put(cdev->owner);
518 	} else {
519 		lirc_irctl_cleanup(ir);
520 		cdev_del(cdev);
521 		irctls[ir->d.minor] = NULL;
522 		kfree(cdev);
523 		kfree(ir);
524 	}
525 
526 	mutex_unlock(&lirc_dev_lock);
527 
528 	return 0;
529 }
530 EXPORT_SYMBOL(lirc_dev_fop_close);
531 
lirc_dev_fop_poll(struct file * file,poll_table * wait)532 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait)
533 {
534 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
535 	unsigned int ret;
536 
537 	if (!ir) {
538 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
539 		return POLLERR;
540 	}
541 
542 	dev_dbg(ir->d.dev, LOGHEAD "poll called\n", ir->d.name, ir->d.minor);
543 
544 	if (!ir->attached)
545 		return POLLERR;
546 
547 	poll_wait(file, &ir->buf->wait_poll, wait);
548 
549 	if (ir->buf)
550 		if (lirc_buffer_empty(ir->buf))
551 			ret = 0;
552 		else
553 			ret = POLLIN | POLLRDNORM;
554 	else
555 		ret = POLLERR;
556 
557 	dev_dbg(ir->d.dev, LOGHEAD "poll result = %d\n",
558 		ir->d.name, ir->d.minor, ret);
559 
560 	return ret;
561 }
562 EXPORT_SYMBOL(lirc_dev_fop_poll);
563 
lirc_dev_fop_ioctl(struct file * file,unsigned int cmd,unsigned long arg)564 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
565 {
566 	__u32 mode;
567 	int result = 0;
568 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
569 
570 	if (!ir) {
571 		printk(KERN_ERR "lirc_dev: %s: no irctl found!\n", __func__);
572 		return -ENODEV;
573 	}
574 
575 	dev_dbg(ir->d.dev, LOGHEAD "ioctl called (0x%x)\n",
576 		ir->d.name, ir->d.minor, cmd);
577 
578 	if (ir->d.minor == NOPLUG || !ir->attached) {
579 		dev_dbg(ir->d.dev, LOGHEAD "ioctl result = -ENODEV\n",
580 			ir->d.name, ir->d.minor);
581 		return -ENODEV;
582 	}
583 
584 	mutex_lock(&ir->irctl_lock);
585 
586 	switch (cmd) {
587 	case LIRC_GET_FEATURES:
588 		result = put_user(ir->d.features, (__u32 *)arg);
589 		break;
590 	case LIRC_GET_REC_MODE:
591 		if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
592 			result = -ENOSYS;
593 			break;
594 		}
595 
596 		result = put_user(LIRC_REC2MODE
597 				  (ir->d.features & LIRC_CAN_REC_MASK),
598 				  (__u32 *)arg);
599 		break;
600 	case LIRC_SET_REC_MODE:
601 		if (!(ir->d.features & LIRC_CAN_REC_MASK)) {
602 			result = -ENOSYS;
603 			break;
604 		}
605 
606 		result = get_user(mode, (__u32 *)arg);
607 		if (!result && !(LIRC_MODE2REC(mode) & ir->d.features))
608 			result = -EINVAL;
609 		/*
610 		 * FIXME: We should actually set the mode somehow but
611 		 * for now, lirc_serial doesn't support mode changing either
612 		 */
613 		break;
614 	case LIRC_GET_LENGTH:
615 		result = put_user(ir->d.code_length, (__u32 *)arg);
616 		break;
617 	case LIRC_GET_MIN_TIMEOUT:
618 		if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
619 		    ir->d.min_timeout == 0) {
620 			result = -ENOSYS;
621 			break;
622 		}
623 
624 		result = put_user(ir->d.min_timeout, (__u32 *)arg);
625 		break;
626 	case LIRC_GET_MAX_TIMEOUT:
627 		if (!(ir->d.features & LIRC_CAN_SET_REC_TIMEOUT) ||
628 		    ir->d.max_timeout == 0) {
629 			result = -ENOSYS;
630 			break;
631 		}
632 
633 		result = put_user(ir->d.max_timeout, (__u32 *)arg);
634 		break;
635 	default:
636 		result = -EINVAL;
637 	}
638 
639 	dev_dbg(ir->d.dev, LOGHEAD "ioctl result = %d\n",
640 		ir->d.name, ir->d.minor, result);
641 
642 	mutex_unlock(&ir->irctl_lock);
643 
644 	return result;
645 }
646 EXPORT_SYMBOL(lirc_dev_fop_ioctl);
647 
lirc_dev_fop_read(struct file * file,char __user * buffer,size_t length,loff_t * ppos)648 ssize_t lirc_dev_fop_read(struct file *file,
649 			  char __user *buffer,
650 			  size_t length,
651 			  loff_t *ppos)
652 {
653 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
654 	unsigned char *buf;
655 	int ret = 0, written = 0;
656 	DECLARE_WAITQUEUE(wait, current);
657 
658 	if (!ir) {
659 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
660 		return -ENODEV;
661 	}
662 
663 	dev_dbg(ir->d.dev, LOGHEAD "read called\n", ir->d.name, ir->d.minor);
664 
665 	buf = kzalloc(ir->chunk_size, GFP_KERNEL);
666 	if (!buf)
667 		return -ENOMEM;
668 
669 	if (mutex_lock_interruptible(&ir->irctl_lock)) {
670 		ret = -ERESTARTSYS;
671 		goto out_unlocked;
672 	}
673 	if (!ir->attached) {
674 		ret = -ENODEV;
675 		goto out_locked;
676 	}
677 
678 	if (length % ir->chunk_size) {
679 		ret = -EINVAL;
680 		goto out_locked;
681 	}
682 
683 	/*
684 	 * we add ourselves to the task queue before buffer check
685 	 * to avoid losing scan code (in case when queue is awaken somewhere
686 	 * between while condition checking and scheduling)
687 	 */
688 	add_wait_queue(&ir->buf->wait_poll, &wait);
689 	set_current_state(TASK_INTERRUPTIBLE);
690 
691 	/*
692 	 * while we didn't provide 'length' bytes, device is opened in blocking
693 	 * mode and 'copy_to_user' is happy, wait for data.
694 	 */
695 	while (written < length && ret == 0) {
696 		if (lirc_buffer_empty(ir->buf)) {
697 			/* According to the read(2) man page, 'written' can be
698 			 * returned as less than 'length', instead of blocking
699 			 * again, returning -EWOULDBLOCK, or returning
700 			 * -ERESTARTSYS */
701 			if (written)
702 				break;
703 			if (file->f_flags & O_NONBLOCK) {
704 				ret = -EWOULDBLOCK;
705 				break;
706 			}
707 			if (signal_pending(current)) {
708 				ret = -ERESTARTSYS;
709 				break;
710 			}
711 
712 			mutex_unlock(&ir->irctl_lock);
713 			schedule();
714 			set_current_state(TASK_INTERRUPTIBLE);
715 
716 			if (mutex_lock_interruptible(&ir->irctl_lock)) {
717 				ret = -ERESTARTSYS;
718 				remove_wait_queue(&ir->buf->wait_poll, &wait);
719 				set_current_state(TASK_RUNNING);
720 				goto out_unlocked;
721 			}
722 
723 			if (!ir->attached) {
724 				ret = -ENODEV;
725 				break;
726 			}
727 		} else {
728 			lirc_buffer_read(ir->buf, buf);
729 			ret = copy_to_user((void *)buffer+written, buf,
730 					   ir->buf->chunk_size);
731 			if (!ret)
732 				written += ir->buf->chunk_size;
733 			else
734 				ret = -EFAULT;
735 		}
736 	}
737 
738 	remove_wait_queue(&ir->buf->wait_poll, &wait);
739 	set_current_state(TASK_RUNNING);
740 
741 out_locked:
742 	mutex_unlock(&ir->irctl_lock);
743 
744 out_unlocked:
745 	kfree(buf);
746 	dev_dbg(ir->d.dev, LOGHEAD "read result = %s (%d)\n",
747 		ir->d.name, ir->d.minor, ret ? "<fail>" : "<ok>", ret);
748 
749 	return ret ? ret : written;
750 }
751 EXPORT_SYMBOL(lirc_dev_fop_read);
752 
lirc_get_pdata(struct file * file)753 void *lirc_get_pdata(struct file *file)
754 {
755 	void *data = NULL;
756 
757 	if (file && file->f_dentry && file->f_dentry->d_inode &&
758 	    file->f_dentry->d_inode->i_rdev) {
759 		struct irctl *ir;
760 		ir = irctls[iminor(file->f_dentry->d_inode)];
761 		data = ir->d.data;
762 	}
763 
764 	return data;
765 }
766 EXPORT_SYMBOL(lirc_get_pdata);
767 
768 
lirc_dev_fop_write(struct file * file,const char __user * buffer,size_t length,loff_t * ppos)769 ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
770 			   size_t length, loff_t *ppos)
771 {
772 	struct irctl *ir = irctls[iminor(file->f_dentry->d_inode)];
773 
774 	if (!ir) {
775 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
776 		return -ENODEV;
777 	}
778 
779 	dev_dbg(ir->d.dev, LOGHEAD "write called\n", ir->d.name, ir->d.minor);
780 
781 	if (!ir->attached)
782 		return -ENODEV;
783 
784 	return -EINVAL;
785 }
786 EXPORT_SYMBOL(lirc_dev_fop_write);
787 
788 
lirc_dev_init(void)789 static int __init lirc_dev_init(void)
790 {
791 	int retval;
792 
793 	lirc_class = class_create(THIS_MODULE, "lirc");
794 	if (IS_ERR(lirc_class)) {
795 		retval = PTR_ERR(lirc_class);
796 		printk(KERN_ERR "lirc_dev: class_create failed\n");
797 		goto error;
798 	}
799 
800 	retval = alloc_chrdev_region(&lirc_base_dev, 0, MAX_IRCTL_DEVICES,
801 				     IRCTL_DEV_NAME);
802 	if (retval) {
803 		class_destroy(lirc_class);
804 		printk(KERN_ERR "lirc_dev: alloc_chrdev_region failed\n");
805 		goto error;
806 	}
807 
808 
809 	printk(KERN_INFO "lirc_dev: IR Remote Control driver registered, "
810 	       "major %d \n", MAJOR(lirc_base_dev));
811 
812 error:
813 	return retval;
814 }
815 
816 
817 
lirc_dev_exit(void)818 static void __exit lirc_dev_exit(void)
819 {
820 	class_destroy(lirc_class);
821 	unregister_chrdev_region(lirc_base_dev, MAX_IRCTL_DEVICES);
822 	printk(KERN_INFO "lirc_dev: module unloaded\n");
823 }
824 
825 module_init(lirc_dev_init);
826 module_exit(lirc_dev_exit);
827 
828 MODULE_DESCRIPTION("LIRC base driver module");
829 MODULE_AUTHOR("Artur Lipowski");
830 MODULE_LICENSE("GPL");
831 
832 module_param(debug, bool, S_IRUGO | S_IWUSR);
833 MODULE_PARM_DESC(debug, "Enable debugging messages");
834