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