summaryrefslogtreecommitdiffstats
path: root/drivers/net/irda/irtty-sir.c
blob: 6a98b7ae4975d9066e840707e8d095e183075b46 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
/*********************************************************************
 *                
 * Filename:      irtty-sir.c
 * Version:       2.0
 * Description:   IrDA line discipline implementation
 * Status:        Experimental.
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Tue Dec  9 21:18:38 1997
 * Modified at:   Sun Oct 27 22:13:30 2002
 * Modified by:   Martin Diehl <mad@mdiehl.de>
 * Sources:       slip.c by Laurence Culhane,   <loz@holmes.demon.co.uk>
 *                          Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
 * 
 *     Copyright (c) 1998-2000 Dag Brattli,
 *     Copyright (c) 2002 Martin Diehl,
 *     All Rights Reserved.
 *      
 *     This program is free software; you can redistribute it and/or 
 *     modify it under the terms of the GNU General Public License as 
 *     published by the Free Software Foundation; either version 2 of 
 *     the License, or (at your option) any later version.
 *  
 *     Neither Dag Brattli nor University of Tromsø admit liability nor
 *     provide warranty for any of this software. This material is 
 *     provided "AS-IS" and at no charge.
 *     
 ********************************************************************/    

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>
#include <linux/mutex.h>

#include <net/irda/irda.h>
#include <net/irda/irda_device.h>

#include "sir-dev.h"
#include "irtty-sir.h"

static int qos_mtt_bits = 0x03;      /* 5 ms or more */

module_param(qos_mtt_bits, int, 0);
MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");

/* ------------------------------------------------------- */

/* device configuration callbacks always invoked with irda-thread context */

/* find out, how many chars we have in buffers below us
 * this is allowed to lie, i.e. return less chars than we
 * actually have. The returned value is used to determine
 * how long the irdathread should wait before doing the
 * real blocking wait_until_sent()
 */

static int irtty_chars_in_buffer(struct sir_dev *dev)
{
	struct sirtty_cb *priv = dev->priv;

	IRDA_ASSERT(priv != NULL, return -1;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);

	return priv->tty->driver->chars_in_buffer(priv->tty);
}

/* Wait (sleep) until underlaying hardware finished transmission
 * i.e. hardware buffers are drained
 * this must block and not return before all characters are really sent
 *
 * If the tty sits on top of a 16550A-like uart, there are typically
 * up to 16 bytes in the fifo - f.e. 9600 bps 8N1 needs 16.7 msec
 *
 * With usbserial the uart-fifo is basically replaced by the converter's
 * outgoing endpoint buffer, which can usually hold 64 bytes (at least).
 * With pl2303 it appears we are safe with 60msec here.
 *
 * I really wish all serial drivers would provide
 * correct implementation of wait_until_sent()
 */

#define USBSERIAL_TX_DONE_DELAY	60

static void irtty_wait_until_sent(struct sir_dev *dev)
{
	struct sirtty_cb *priv = dev->priv;
	struct tty_struct *tty;

	IRDA_ASSERT(priv != NULL, return;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);

	tty = priv->tty;
	if (tty->driver->wait_until_sent) {
		lock_kernel();
		tty->driver->wait_until_sent(tty, msecs_to_jiffies(100));
		unlock_kernel();
	}
	else {
		msleep(USBSERIAL_TX_DONE_DELAY);
	}
}

/* 
 *  Function irtty_change_speed (dev, speed)
 *
 *    Change the speed of the serial port.
 *
 * This may sleep in set_termios (usbserial driver f.e.) and must
 * not be called from interrupt/timer/tasklet therefore.
 * All such invocations are deferred to kIrDAd now so we can sleep there.
 */

static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
{
	struct sirtty_cb *priv = dev->priv;
	struct tty_struct *tty;
        struct termios old_termios;
	int cflag;

	IRDA_ASSERT(priv != NULL, return -1;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);

	tty = priv->tty;

	lock_kernel();
	old_termios = *(tty->termios);
	cflag = tty->termios->c_cflag;

	cflag &= ~CBAUD;

	IRDA_DEBUG(2, "%s(), Setting speed to %d\n", __FUNCTION__, speed);

	switch (speed) {
	case 1200:
		cflag |= B1200;
		break;
	case 2400:
		cflag |= B2400;
		break;
	case 4800:
		cflag |= B4800;
		break;
	case 19200:
		cflag |= B19200;
		break;
	case 38400:
		cflag |= B38400;
		break;
	case 57600:
		cflag |= B57600;
		break;
	case 115200:
		cflag |= B115200;
		break;
	case 9600:
	default:
		cflag |= B9600;
		break;
	}	

	tty->termios->c_cflag = cflag;
	if (tty->driver->set_termios)
		tty->driver->set_termios(tty, &old_termios);
	unlock_kernel();

	priv->io.speed = speed;

	return 0;
}

/*
 * Function irtty_set_dtr_rts (dev, dtr, rts)
 *
 *    This function can be used by dongles etc. to set or reset the status
 *    of the dtr and rts lines
 */

static int irtty_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
{
	struct sirtty_cb *priv = dev->priv;
	int set = 0;
	int clear = 0;

	IRDA_ASSERT(priv != NULL, return -1;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);

	if (rts)
		set |= TIOCM_RTS;
	else
		clear |= TIOCM_RTS;
	if (dtr)
		set |= TIOCM_DTR;
	else
		clear |= TIOCM_DTR;

	/*
	 * We can't use ioctl() because it expects a non-null file structure,
	 * and we don't have that here.
	 * This function is not yet defined for all tty driver, so
	 * let's be careful... Jean II
	 */
	IRDA_ASSERT(priv->tty->driver->tiocmset != NULL, return -1;);
	priv->tty->driver->tiocmset(priv->tty, NULL, set, clear);

	return 0;
}

/* ------------------------------------------------------- */

/* called from sir_dev when there is more data to send
 * context is either netdev->hard_xmit or some transmit-completion bh
 * i.e. we are under spinlock here and must not sleep.
 */

static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t len)
{
	struct sirtty_cb *priv = dev->priv;
	struct tty_struct *tty;
	int writelen;

	IRDA_ASSERT(priv != NULL, return -1;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);

	tty = priv->tty;
	if (!tty->driver->write)
		return 0;
	tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
	if (tty->driver->write_room) {
		writelen = tty->driver->write_room(tty);
		if (writelen > len)
			writelen = len;
	}
	else
		writelen = len;
	return tty->driver->write(tty, ptr, writelen);
}

/* ------------------------------------------------------- */

/* irda line discipline callbacks */

/* 
 *  Function irtty_receive_buf( tty, cp, count)
 *
 *    Handle the 'receiver data ready' interrupt.  This function is called
 *    by the 'tty_io' module in the kernel when a block of IrDA data has
 *    been received, which can now be decapsulated and delivered for
 *    further processing 
 *
 * calling context depends on underlying driver and tty->low_latency!
 * for example (low_latency: 1 / 0):
 * serial.c:	uart-interrupt / softint
 * usbserial:	urb-complete-interrupt / softint
 */

static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
			      char *fp, int count) 
{
	struct sir_dev *dev;
	struct sirtty_cb *priv = tty->disc_data;
	int	i;

	IRDA_ASSERT(priv != NULL, return;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);

	if (unlikely(count==0))		/* yes, this happens */
		return;

	dev = priv->dev;
	if (!dev) {
		IRDA_WARNING("%s(), not ready yet!\n", __FUNCTION__);
		return;
	}

	for (i = 0; i < count; i++) {
		/* 
		 *  Characters received with a parity error, etc?
		 */
 		if (fp && *fp++) { 
			IRDA_DEBUG(0, "Framing or parity error!\n");
			sirdev_receive(dev, NULL, 0);	/* notify sir_dev (updating stats) */
			return;
 		}
	}

	sirdev_receive(dev, cp, count);
}

/*
 * Function irtty_write_wakeup (tty)
 *
 *    Called by the driver when there's room for more data.  If we have
 *    more packets to send, we send them here.
 *
 */
static void irtty_write_wakeup(struct tty_struct *tty) 
{
	struct sirtty_cb *priv = tty->disc_data;

	IRDA_ASSERT(priv != NULL, return;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);

	tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);

	if (priv->dev)
		sirdev_write_complete(priv->dev);
}

/* ------------------------------------------------------- */

/*
 * Function irtty_stop_receiver (tty, stop)
 *
 */

static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
{
	struct termios old_termios;
	int cflag;

	lock_kernel();
	old_termios = *(tty->termios);
	cflag = tty->termios->c_cflag;
	
	if (stop)
		cflag &= ~CREAD;
	else
		cflag |= CREAD;

	tty->termios->c_cflag = cflag;
	if (tty->driver->set_termios)
		tty->driver->set_termios(tty, &old_termios);
	unlock_kernel();
}

/*****************************************************************/

/* serialize ldisc open/close with sir_dev */
static DEFINE_MUTEX(irtty_mutex);

/* notifier from sir_dev when irda% device gets opened (ifup) */

static int irtty_start_dev(struct sir_dev *dev)
{
	struct sirtty_cb *priv;
	struct tty_struct *tty;

	/* serialize with ldisc open/close */
	mutex_lock(&irtty_mutex);

	priv = dev->priv;
	if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
		mutex_unlock(&irtty_mutex);
		return -ESTALE;
	}

	tty = priv->tty;

	if (tty->driver->start)
		tty->driver->start(tty);
	/* Make sure we can receive more data */
	irtty_stop_receiver(tty, FALSE);

	mutex_unlock(&irtty_mutex);
	return 0;
}

/* notifier from sir_dev when irda% device gets closed (ifdown) */

static int irtty_stop_dev(struct sir_dev *dev)
{
	struct sirtty_cb *priv;
	struct tty_struct *tty;

	/* serialize with ldisc open/close */
	mutex_lock(&irtty_mutex);

	priv = dev->priv;
	if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
		mutex_unlock(&irtty_mutex);
		return -ESTALE;
	}

	tty = priv->tty;

	/* Make sure we don't receive more data */
	irtty_stop_receiver(tty, TRUE);
	if (tty->driver->stop)
		tty->driver->stop(tty);

	mutex_unlock(&irtty_mutex);

	return 0;
}

/* ------------------------------------------------------- */

static struct sir_driver sir_tty_drv = {
	.owner			= THIS_MODULE,
	.driver_name		= "sir_tty",
	.start_dev		= irtty_start_dev,
	.stop_dev		= irtty_stop_dev,
	.do_write		= irtty_do_write,
	.chars_in_buffer	= irtty_chars_in_buffer,
	.wait_until_sent	= irtty_wait_until_sent,
	.set_speed		= irtty_change_speed,
	.set_dtr_rts		= irtty_set_dtr_rts,
};

/* ------------------------------------------------------- */

/*
 * Function irtty_ioctl (tty, file, cmd, arg)
 *
 *     The Swiss army knife of system calls :-)
 *
 */
static int irtty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
{
	struct irtty_info { char name[6]; } info;
	struct sir_dev *dev;
	struct sirtty_cb *priv = tty->disc_data;
	int err = 0;

	IRDA_ASSERT(priv != NULL, return -ENODEV;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EBADR;);

	IRDA_DEBUG(3, "%s(cmd=0x%X)\n", __FUNCTION__, cmd);

	dev = priv->dev;
	IRDA_ASSERT(dev != NULL, return -1;);

	switch (cmd) {
	case TCGETS:
	case TCGETA:
		err = n_tty_ioctl(tty, file, cmd, arg);
		break;

	case IRTTY_IOCTDONGLE:
		/* this call blocks for completion */
		err = sirdev_set_dongle(dev, (IRDA_DONGLE) arg);
		break;

	case IRTTY_IOCGET:
		IRDA_ASSERT(dev->netdev != NULL, return -1;);

		memset(&info, 0, sizeof(info)); 
		strncpy(info.name, dev->netdev->name, sizeof(info.name)-1);

		if (copy_to_user((void __user *)arg, &info, sizeof(info)))
			err = -EFAULT;
		break;
	default:
		err = -ENOIOCTLCMD;
		break;
	}
	return err;
}


/* 
 *  Function irtty_open(tty)
 *
 *    This function is called by the TTY module when the IrDA line
 *    discipline is called for.  Because we are sure the tty line exists,
 *    we only have to link it to a free IrDA channel.  
 */
static int irtty_open(struct tty_struct *tty) 
{
	struct sir_dev *dev;
	struct sirtty_cb *priv;
	int ret = 0;

	/* Module stuff handled via irda_ldisc.owner - Jean II */

	/* First make sure we're not already connected. */
	if (tty->disc_data != NULL) {
		priv = tty->disc_data;
		if (priv && priv->magic == IRTTY_MAGIC) {
			ret = -EEXIST;
			goto out;
		}
		tty->disc_data = NULL;		/* ### */
	}

	/* stop the underlying  driver */
	irtty_stop_receiver(tty, TRUE);
	if (tty->driver->stop)
		tty->driver->stop(tty);

	if (tty->driver->flush_buffer)
		tty->driver->flush_buffer(tty);
	
	/* apply mtt override */
	sir_tty_drv.qos_mtt_bits = qos_mtt_bits;

	/* get a sir device instance for this driver */
	dev = sirdev_get_instance(&sir_tty_drv, tty->name);
	if (!dev) {
		ret = -ENODEV;
		goto out;
	}

	/* allocate private device info block */
	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
		goto out_put;
	memset(priv, 0, sizeof(*priv));

	priv->magic = IRTTY_MAGIC;
	priv->tty = tty;
	priv->dev = dev;

	/* serialize with start_dev - in case we were racing with ifup */
	mutex_lock(&irtty_mutex);

	dev->priv = priv;
	tty->disc_data = priv;
	tty->receive_room = 65536;

	mutex_unlock(&irtty_mutex);

	IRDA_DEBUG(0, "%s - %s: irda line discipline opened\n", __FUNCTION__, tty->name);

	return 0;

out_put:
	sirdev_put_instance(dev);
out:
	return ret;
}

/* 
 *  Function irtty_close (tty)
 *
 *    Close down a IrDA channel. This means flushing out any pending queues,
 *    and then restoring the TTY line discipline to what it was before it got
 *    hooked to IrDA (which usually is TTY again).  
 */
static void irtty_close(struct tty_struct *tty) 
{
	struct sirtty_cb *priv = tty->disc_data;

	IRDA_ASSERT(priv != NULL, return;);
	IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);

	/* Hm, with a dongle attached the dongle driver wants
	 * to close the dongle - which requires the use of
	 * some tty write and/or termios or ioctl operations.
	 * Are we allowed to call those when already requested
	 * to shutdown the ldisc?
	 * If not, we should somehow mark the dev being staled.
	 * Question remains, how to close the dongle in this case...
	 * For now let's assume we are granted to issue tty driver calls
	 * until we return here from the ldisc close. I'm just wondering
	 * how this behaves with hotpluggable serial hardware like
	 * rs232-pcmcia card or usb-serial...
	 *
	 * priv->tty = NULL?;
	 */

	/* we are dead now */
	tty->disc_data = NULL;

	sirdev_put_instance(priv->dev);

	/* Stop tty */
	irtty_stop_receiver(tty, TRUE);
	tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
	if (tty->driver->stop)
		tty->driver->stop(tty);

	kfree(priv);

	IRDA_DEBUG(0, "%s - %s: irda line discipline closed\n", __FUNCTION__, tty->name);
}

/* ------------------------------------------------------- */

static struct tty_ldisc irda_ldisc = {
	.magic		= TTY_LDISC_MAGIC,
 	.name		= "irda",
	.flags		= 0,
	.open		= irtty_open,
	.close		= irtty_close,
	.read		= NULL,
	.write		= NULL,
	.ioctl		= irtty_ioctl,
 	.poll		= NULL,
	.receive_buf	= irtty_receive_buf,
	.write_wakeup	= irtty_write_wakeup,
	.owner		= THIS_MODULE,
};

/* ------------------------------------------------------- */

static int __init irtty_sir_init(void)
{
	int err;

	if ((err = tty_register_ldisc(N_IRDA, &irda_ldisc)) != 0)
		IRDA_ERROR("IrDA: can't register line discipline (err = %d)\n",
			   err);
	return err;
}

static void __exit irtty_sir_cleanup(void) 
{
	int err;

	if ((err = tty_unregister_ldisc(N_IRDA))) {
		IRDA_ERROR("%s(), can't unregister line discipline (err = %d)\n",
			   __FUNCTION__, err);
	}
}

module_init(irtty_sir_init);
module_exit(irtty_sir_cleanup);

MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
MODULE_DESCRIPTION("IrDA TTY device driver");
MODULE_ALIAS_LDISC(N_IRDA);
MODULE_LICENSE("GPL");

OpenPOWER on IntegriCloud