1 /*********************************************************************
2 *
3 * Filename: irtty-sir.c
4 * Version: 2.0
5 * Description: IrDA line discipline implementation
6 * Status: Experimental.
7 * Author: Dag Brattli <dagb@cs.uit.no>
8 * Created at: Tue Dec 9 21:18:38 1997
9 * Modified at: Sun Oct 27 22:13:30 2002
10 * Modified by: Martin Diehl <mad@mdiehl.de>
11 * Sources: slip.c by Laurence Culhane, <loz@holmes.demon.co.uk>
12 * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
13 *
14 * Copyright (c) 1998-2000 Dag Brattli,
15 * Copyright (c) 2002 Martin Diehl,
16 * All Rights Reserved.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License as
20 * published by the Free Software Foundation; either version 2 of
21 * the License, or (at your option) any later version.
22 *
23 * Neither Dag Brattli nor University of Tromsø admit liability nor
24 * provide warranty for any of this software. This material is
25 * provided "AS-IS" and at no charge.
26 *
27 ********************************************************************/
28
29 #include <linux/module.h>
30 #include <linux/kernel.h>
31 #include <linux/tty.h>
32 #include <linux/init.h>
33 #include <asm/uaccess.h>
34 #include <linux/delay.h>
35 #include <linux/mutex.h>
36
37 #include <net/irda/irda.h>
38 #include <net/irda/irda_device.h>
39
40 #include "sir-dev.h"
41 #include "irtty-sir.h"
42
43 static int qos_mtt_bits = 0x03; /* 5 ms or more */
44
45 module_param(qos_mtt_bits, int, 0);
46 MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
47
48 /* ------------------------------------------------------- */
49
50 /* device configuration callbacks always invoked with irda-thread context */
51
52 /* find out, how many chars we have in buffers below us
53 * this is allowed to lie, i.e. return less chars than we
54 * actually have. The returned value is used to determine
55 * how long the irdathread should wait before doing the
56 * real blocking wait_until_sent()
57 */
58
59 static int irtty_chars_in_buffer(struct sir_dev *dev)
60 {
61 struct sirtty_cb *priv = dev->priv;
62
63 IRDA_ASSERT(priv != NULL, return -1;);
64 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
65
66 return tty_chars_in_buffer(priv->tty);
67 }
68
69 /* Wait (sleep) until underlaying hardware finished transmission
70 * i.e. hardware buffers are drained
71 * this must block and not return before all characters are really sent
72 *
73 * If the tty sits on top of a 16550A-like uart, there are typically
74 * up to 16 bytes in the fifo - f.e. 9600 bps 8N1 needs 16.7 msec
75 *
76 * With usbserial the uart-fifo is basically replaced by the converter's
77 * outgoing endpoint buffer, which can usually hold 64 bytes (at least).
78 * With pl2303 it appears we are safe with 60msec here.
79 *
80 * I really wish all serial drivers would provide
81 * correct implementation of wait_until_sent()
82 */
83
84 #define USBSERIAL_TX_DONE_DELAY 60
85
86 static void irtty_wait_until_sent(struct sir_dev *dev)
87 {
88 struct sirtty_cb *priv = dev->priv;
89 struct tty_struct *tty;
90
91 IRDA_ASSERT(priv != NULL, return;);
92 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
93
94 tty = priv->tty;
95 if (tty->ops->wait_until_sent) {
96 tty->ops->wait_until_sent(tty, msecs_to_jiffies(100));
97 }
98 else {
99 msleep(USBSERIAL_TX_DONE_DELAY);
100 }
101 }
102
103 /*
104 * Function irtty_change_speed (dev, speed)
105 *
106 * Change the speed of the serial port.
107 *
108 * This may sleep in set_termios (usbserial driver f.e.) and must
109 * not be called from interrupt/timer/tasklet therefore.
110 * All such invocations are deferred to kIrDAd now so we can sleep there.
111 */
112
113 static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
114 {
115 struct sirtty_cb *priv = dev->priv;
116 struct tty_struct *tty;
117 struct ktermios old_termios;
118 int cflag;
119
120 IRDA_ASSERT(priv != NULL, return -1;);
121 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
122
123 tty = priv->tty;
124
125 mutex_lock(&tty->termios_mutex);
126 old_termios = *(tty->termios);
127 cflag = tty->termios->c_cflag;
128 tty_encode_baud_rate(tty, speed, speed);
129 if (tty->ops->set_termios)
130 tty->ops->set_termios(tty, &old_termios);
131 priv->io.speed = speed;
132 mutex_unlock(&tty->termios_mutex);
133
134 return 0;
135 }
136
137 /*
138 * Function irtty_set_dtr_rts (dev, dtr, rts)
139 *
140 * This function can be used by dongles etc. to set or reset the status
141 * of the dtr and rts lines
142 */
143
144 static int irtty_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
145 {
146 struct sirtty_cb *priv = dev->priv;
147 int set = 0;
148 int clear = 0;
149
150 IRDA_ASSERT(priv != NULL, return -1;);
151 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
152
153 if (rts)
154 set |= TIOCM_RTS;
155 else
156 clear |= TIOCM_RTS;
157 if (dtr)
158 set |= TIOCM_DTR;
159 else
160 clear |= TIOCM_DTR;
161
162 /*
163 * We can't use ioctl() because it expects a non-null file structure,
164 * and we don't have that here.
165 * This function is not yet defined for all tty driver, so
166 * let's be careful... Jean II
167 */
168 IRDA_ASSERT(priv->tty->ops->tiocmset != NULL, return -1;);
169 priv->tty->ops->tiocmset(priv->tty, NULL, set, clear);
170
171 return 0;
172 }
173
174 /* ------------------------------------------------------- */
175
176 /* called from sir_dev when there is more data to send
177 * context is either netdev->hard_xmit or some transmit-completion bh
178 * i.e. we are under spinlock here and must not sleep.
179 */
180
181 static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t len)
182 {
183 struct sirtty_cb *priv = dev->priv;
184 struct tty_struct *tty;
185 int writelen;
186
187 IRDA_ASSERT(priv != NULL, return -1;);
188 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
189
190 tty = priv->tty;
191 if (!tty->ops->write)
192 return 0;
193 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
194 writelen = tty_write_room(tty);
195 if (writelen > len)
196 writelen = len;
197 return tty->ops->write(tty, ptr, writelen);
198 }
199
200 /* ------------------------------------------------------- */
201
202 /* irda line discipline callbacks */
203
204 /*
205 * Function irtty_receive_buf( tty, cp, count)
206 *
207 * Handle the 'receiver data ready' interrupt. This function is called
208 * by the 'tty_io' module in the kernel when a block of IrDA data has
209 * been received, which can now be decapsulated and delivered for
210 * further processing
211 *
212 * calling context depends on underlying driver and tty->low_latency!
213 * for example (low_latency: 1 / 0):
214 * serial.c: uart-interrupt / softint
215 * usbserial: urb-complete-interrupt / softint
216 */
217
218 static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
219 char *fp, int count)
220 {
221 struct sir_dev *dev;
222 struct sirtty_cb *priv = tty->disc_data;
223 int i;
224
225 IRDA_ASSERT(priv != NULL, return;);
226 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
227
228 if (unlikely(count==0)) /* yes, this happens */
229 return;
230
231 dev = priv->dev;
232 if (!dev) {
233 IRDA_WARNING("%s(), not ready yet!\n", __func__);
234 return;
235 }
236
237 for (i = 0; i < count; i++) {
238 /*
239 * Characters received with a parity error, etc?
240 */
241 if (fp && *fp++) {
242 IRDA_DEBUG(0, "Framing or parity error!\n");
243 sirdev_receive(dev, NULL, 0); /* notify sir_dev (updating stats) */
244 return;
245 }
246 }
247
248 sirdev_receive(dev, cp, count);
249 }
250
251 /*
252 * Function irtty_write_wakeup (tty)
253 *
254 * Called by the driver when there's room for more data. If we have
255 * more packets to send, we send them here.
256 *
257 */
258 static void irtty_write_wakeup(struct tty_struct *tty)
259 {
260 struct sirtty_cb *priv = tty->disc_data;
261
262 IRDA_ASSERT(priv != NULL, return;);
263 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
264
265 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
266 if (priv->dev)
267 sirdev_write_complete(priv->dev);
268 }
269
270 /* ------------------------------------------------------- */
271
272 /*
273 * Function irtty_stop_receiver (tty, stop)
274 *
275 */
276
277 static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
278 {
279 struct ktermios old_termios;
280 int cflag;
281
282 mutex_lock(&tty->termios_mutex);
283 old_termios = *(tty->termios);
284 cflag = tty->termios->c_cflag;
285
286 if (stop)
287 cflag &= ~CREAD;
288 else
289 cflag |= CREAD;
290
291 tty->termios->c_cflag = cflag;
292 if (tty->ops->set_termios)
293 tty->ops->set_termios(tty, &old_termios);
294 mutex_unlock(&tty->termios_mutex);
295 }
296
297 /*****************************************************************/
298
299 /* serialize ldisc open/close with sir_dev */
300 static DEFINE_MUTEX(irtty_mutex);
301
302 /* notifier from sir_dev when irda% device gets opened (ifup) */
303
304 static int irtty_start_dev(struct sir_dev *dev)
305 {
306 struct sirtty_cb *priv;
307 struct tty_struct *tty;
308
309 /* serialize with ldisc open/close */
310 mutex_lock(&irtty_mutex);
311
312 priv = dev->priv;
313 if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
314 mutex_unlock(&irtty_mutex);
315 return -ESTALE;
316 }
317
318 tty = priv->tty;
319
320 if (tty->ops->start)
321 tty->ops->start(tty);
322 /* Make sure we can receive more data */
323 irtty_stop_receiver(tty, FALSE);
324
325 mutex_unlock(&irtty_mutex);
326 return 0;
327 }
328
329 /* notifier from sir_dev when irda% device gets closed (ifdown) */
330
331 static int irtty_stop_dev(struct sir_dev *dev)
332 {
333 struct sirtty_cb *priv;
334 struct tty_struct *tty;
335
336 /* serialize with ldisc open/close */
337 mutex_lock(&irtty_mutex);
338
339 priv = dev->priv;
340 if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
341 mutex_unlock(&irtty_mutex);
342 return -ESTALE;
343 }
344
345 tty = priv->tty;
346
347 /* Make sure we don't receive more data */
348 irtty_stop_receiver(tty, TRUE);
349 if (tty->ops->stop)
350 tty->ops->stop(tty);
351
352 mutex_unlock(&irtty_mutex);
353
354 return 0;
355 }
356
357 /* ------------------------------------------------------- */
358
359 static struct sir_driver sir_tty_drv = {
360 .owner = THIS_MODULE,
361 .driver_name = "sir_tty",
362 .start_dev = irtty_start_dev,
363 .stop_dev = irtty_stop_dev,
364 .do_write = irtty_do_write,
365 .chars_in_buffer = irtty_chars_in_buffer,
366 .wait_until_sent = irtty_wait_until_sent,
367 .set_speed = irtty_change_speed,
368 .set_dtr_rts = irtty_set_dtr_rts,
369 };
370
371 /* ------------------------------------------------------- */
372
373 /*
374 * Function irtty_ioctl (tty, file, cmd, arg)
375 *
376 * The Swiss army knife of system calls :-)
377 *
378 */
379 static int irtty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
380 {
381 struct irtty_info { char name[6]; } info;
382 struct sir_dev *dev;
383 struct sirtty_cb *priv = tty->disc_data;
384 int err = 0;
385
386 IRDA_ASSERT(priv != NULL, return -ENODEV;);
387 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EBADR;);
388
389 IRDA_DEBUG(3, "%s(cmd=0x%X)\n", __func__, cmd);
390
391 dev = priv->dev;
392 IRDA_ASSERT(dev != NULL, return -1;);
393
394 switch (cmd) {
395 case IRTTY_IOCTDONGLE:
396 /* this call blocks for completion */
397 err = sirdev_set_dongle(dev, (IRDA_DONGLE) arg);
398 break;
399
400 case IRTTY_IOCGET:
401 IRDA_ASSERT(dev->netdev != NULL, return -1;);
402
403 memset(&info, 0, sizeof(info));
404 strncpy(info.name, dev->netdev->name, sizeof(info.name)-1);
405
406 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
407 err = -EFAULT;
408 break;
409 default:
410 err = tty_mode_ioctl(tty, file, cmd, arg);
411 break;
412 }
413 return err;
414 }
415
416
417 /*
418 * Function irtty_open(tty)
419 *
420 * This function is called by the TTY module when the IrDA line
421 * discipline is called for. Because we are sure the tty line exists,
422 * we only have to link it to a free IrDA channel.
423 */
424 static int irtty_open(struct tty_struct *tty)
425 {
426 struct sir_dev *dev;
427 struct sirtty_cb *priv;
428 int ret = 0;
429
430 /* Module stuff handled via irda_ldisc.owner - Jean II */
431
432 /* First make sure we're not already connected. */
433 if (tty->disc_data != NULL) {
434 priv = tty->disc_data;
435 if (priv && priv->magic == IRTTY_MAGIC) {
436 ret = -EEXIST;
437 goto out;
438 }
439 tty->disc_data = NULL; /* ### */
440 }
441
442 /* stop the underlying driver */
443 irtty_stop_receiver(tty, TRUE);
444 if (tty->ops->stop)
445 tty->ops->stop(tty);
446
447 tty_driver_flush_buffer(tty);
448
449 /* apply mtt override */
450 sir_tty_drv.qos_mtt_bits = qos_mtt_bits;
451
452 /* get a sir device instance for this driver */
453 dev = sirdev_get_instance(&sir_tty_drv, tty->name);
454 if (!dev) {
455 ret = -ENODEV;
456 goto out;
457 }
458
459 /* allocate private device info block */
460 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
461 if (!priv)
462 goto out_put;
463
464 priv->magic = IRTTY_MAGIC;
465 priv->tty = tty;
466 priv->dev = dev;
467
468 /* serialize with start_dev - in case we were racing with ifup */
469 mutex_lock(&irtty_mutex);
470
471 dev->priv = priv;
472 tty->disc_data = priv;
473 tty->receive_room = 65536;
474
475 mutex_unlock(&irtty_mutex);
476
477 IRDA_DEBUG(0, "%s - %s: irda line discipline opened\n", __func__, tty->name);
478
479 return 0;
480
481 out_put:
482 sirdev_put_instance(dev);
483 out:
484 return ret;
485 }
486
487 /*
488 * Function irtty_close (tty)
489 *
490 * Close down a IrDA channel. This means flushing out any pending queues,
491 * and then restoring the TTY line discipline to what it was before it got
492 * hooked to IrDA (which usually is TTY again).
493 */
494 static void irtty_close(struct tty_struct *tty)
495 {
496 struct sirtty_cb *priv = tty->disc_data;
497
498 IRDA_ASSERT(priv != NULL, return;);
499 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
500
501 /* Hm, with a dongle attached the dongle driver wants
502 * to close the dongle - which requires the use of
503 * some tty write and/or termios or ioctl operations.
504 * Are we allowed to call those when already requested
505 * to shutdown the ldisc?
506 * If not, we should somehow mark the dev being staled.
507 * Question remains, how to close the dongle in this case...
508 * For now let's assume we are granted to issue tty driver calls
509 * until we return here from the ldisc close. I'm just wondering
510 * how this behaves with hotpluggable serial hardware like
511 * rs232-pcmcia card or usb-serial...
512 *
513 * priv->tty = NULL?;
514 */
515
516 /* we are dead now */
517 tty->disc_data = NULL;
518
519 sirdev_put_instance(priv->dev);
520
521 /* Stop tty */
522 irtty_stop_receiver(tty, TRUE);
523 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
524 if (tty->ops->stop)
525 tty->ops->stop(tty);
526
527 kfree(priv);
528
529 IRDA_DEBUG(0, "%s - %s: irda line discipline closed\n", __func__, tty->name);
530 }
531
532 /* ------------------------------------------------------- */
533
534 static struct tty_ldisc_ops irda_ldisc = {
535 .magic = TTY_LDISC_MAGIC,
536 .name = "irda",
537 .flags = 0,
538 .open = irtty_open,
539 .close = irtty_close,
540 .read = NULL,
541 .write = NULL,
542 .ioctl = irtty_ioctl,
543 .poll = NULL,
544 .receive_buf = irtty_receive_buf,
545 .write_wakeup = irtty_write_wakeup,
546 .owner = THIS_MODULE,
547 };
548
549 /* ------------------------------------------------------- */
550
551 static int __init irtty_sir_init(void)
552 {
553 int err;
554
555 if ((err = tty_register_ldisc(N_IRDA, &irda_ldisc)) != 0)
556 IRDA_ERROR("IrDA: can't register line discipline (err = %d)\n",
557 err);
558 return err;
559 }
560
561 static void __exit irtty_sir_cleanup(void)
562 {
563 int err;
564
565 if ((err = tty_unregister_ldisc(N_IRDA))) {
566 IRDA_ERROR("%s(), can't unregister line discipline (err = %d)\n",
567 __func__, err);
568 }
569 }
570
571 module_init(irtty_sir_init);
572 module_exit(irtty_sir_cleanup);
573
574 MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
575 MODULE_DESCRIPTION("IrDA TTY device driver");
576 MODULE_ALIAS_LDISC(N_IRDA);
577 MODULE_LICENSE("GPL");
578
579
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