1 /*********************************************************************
3 * Filename: irtty-sir.c
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>
14 * Copyright (c) 1998-2000 Dag Brattli,
15 * Copyright (c) 2002 Martin Diehl,
16 * All Rights Reserved.
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.
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.
27 ********************************************************************/
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>
38 #include <net/irda/irda.h>
39 #include <net/irda/irda_device.h>
42 #include "irtty-sir.h"
44 static int qos_mtt_bits = 0x03; /* 5 ms or more */
46 module_param(qos_mtt_bits, int, 0);
47 MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
49 /* ------------------------------------------------------- */
51 /* device configuration callbacks always invoked with irda-thread context */
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()
60 static int irtty_chars_in_buffer(struct sir_dev *dev)
62 struct sirtty_cb *priv = dev->priv;
64 IRDA_ASSERT(priv != NULL, return -1;);
65 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
67 return tty_chars_in_buffer(priv->tty);
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
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
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.
81 * I really wish all serial drivers would provide
82 * correct implementation of wait_until_sent()
85 #define USBSERIAL_TX_DONE_DELAY 60
87 static void irtty_wait_until_sent(struct sir_dev *dev)
89 struct sirtty_cb *priv = dev->priv;
90 struct tty_struct *tty;
92 IRDA_ASSERT(priv != NULL, return;);
93 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
96 if (tty->ops->wait_until_sent) {
97 tty->ops->wait_until_sent(tty, msecs_to_jiffies(100));
100 msleep(USBSERIAL_TX_DONE_DELAY);
105 * Function irtty_change_speed (dev, speed)
107 * Change the speed of the serial port.
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.
114 static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
116 struct sirtty_cb *priv = dev->priv;
117 struct tty_struct *tty;
118 struct ktermios old_termios;
121 IRDA_ASSERT(priv != NULL, return -1;);
122 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
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);
139 * Function irtty_set_dtr_rts (dev, dtr, rts)
141 * This function can be used by dongles etc. to set or reset the status
142 * of the dtr and rts lines
145 static int irtty_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
147 struct sirtty_cb *priv = dev->priv;
151 IRDA_ASSERT(priv != NULL, return -1;);
152 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
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
169 IRDA_ASSERT(priv->tty->ops->tiocmset != NULL, return -1;);
170 priv->tty->ops->tiocmset(priv->tty, set, clear);
175 /* ------------------------------------------------------- */
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.
182 static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t len)
184 struct sirtty_cb *priv = dev->priv;
185 struct tty_struct *tty;
188 IRDA_ASSERT(priv != NULL, return -1;);
189 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
192 if (!tty->ops->write)
194 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
195 writelen = tty_write_room(tty);
198 return tty->ops->write(tty, ptr, writelen);
201 /* ------------------------------------------------------- */
203 /* irda line discipline callbacks */
206 * Function irtty_receive_buf( tty, cp, count)
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
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
219 static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
223 struct sirtty_cb *priv = tty->disc_data;
226 IRDA_ASSERT(priv != NULL, return;);
227 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
229 if (unlikely(count==0)) /* yes, this happens */
234 net_warn_ratelimited("%s(), not ready yet!\n", __func__);
238 for (i = 0; i < count; i++) {
240 * Characters received with a parity error, etc?
243 pr_debug("Framing or parity error!\n");
244 sirdev_receive(dev, NULL, 0); /* notify sir_dev (updating stats) */
249 sirdev_receive(dev, cp, count);
253 * Function irtty_write_wakeup (tty)
255 * Called by the driver when there's room for more data. If we have
256 * more packets to send, we send them here.
259 static void irtty_write_wakeup(struct tty_struct *tty)
261 struct sirtty_cb *priv = tty->disc_data;
263 IRDA_ASSERT(priv != NULL, return;);
264 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
266 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
268 sirdev_write_complete(priv->dev);
271 /* ------------------------------------------------------- */
274 * Function irtty_stop_receiver (tty, stop)
278 static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
280 struct ktermios old_termios;
283 down_write(&tty->termios_rwsem);
284 old_termios = tty->termios;
285 cflag = tty->termios.c_cflag;
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);
298 /*****************************************************************/
300 /* serialize ldisc open/close with sir_dev */
301 static DEFINE_MUTEX(irtty_mutex);
303 /* notifier from sir_dev when irda% device gets opened (ifup) */
305 static int irtty_start_dev(struct sir_dev *dev)
307 struct sirtty_cb *priv;
308 struct tty_struct *tty;
310 /* serialize with ldisc open/close */
311 mutex_lock(&irtty_mutex);
314 if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
315 mutex_unlock(&irtty_mutex);
322 tty->ops->start(tty);
323 /* Make sure we can receive more data */
324 irtty_stop_receiver(tty, FALSE);
326 mutex_unlock(&irtty_mutex);
330 /* notifier from sir_dev when irda% device gets closed (ifdown) */
332 static int irtty_stop_dev(struct sir_dev *dev)
334 struct sirtty_cb *priv;
335 struct tty_struct *tty;
337 /* serialize with ldisc open/close */
338 mutex_lock(&irtty_mutex);
341 if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
342 mutex_unlock(&irtty_mutex);
348 /* Make sure we don't receive more data */
349 irtty_stop_receiver(tty, TRUE);
353 mutex_unlock(&irtty_mutex);
358 /* ------------------------------------------------------- */
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,
372 /* ------------------------------------------------------- */
375 * Function irtty_ioctl (tty, file, cmd, arg)
377 * The Swiss army knife of system calls :-)
380 static int irtty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
382 struct irtty_info { char name[6]; } info;
384 struct sirtty_cb *priv = tty->disc_data;
387 IRDA_ASSERT(priv != NULL, return -ENODEV;);
388 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EBADR;);
390 pr_debug("%s(cmd=0x%X)\n", __func__, cmd);
393 IRDA_ASSERT(dev != NULL, return -1;);
396 case IRTTY_IOCTDONGLE:
397 /* this call blocks for completion */
398 err = sirdev_set_dongle(dev, (IRDA_DONGLE) arg);
402 IRDA_ASSERT(dev->netdev != NULL, return -1;);
404 memset(&info, 0, sizeof(info));
405 strncpy(info.name, dev->netdev->name, sizeof(info.name)-1);
407 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
411 err = tty_mode_ioctl(tty, file, cmd, arg);
419 * Function irtty_open(tty)
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.
425 static int irtty_open(struct tty_struct *tty)
428 struct sirtty_cb *priv;
431 /* Module stuff handled via irda_ldisc.owner - Jean II */
433 /* stop the underlying driver */
434 irtty_stop_receiver(tty, TRUE);
438 tty_driver_flush_buffer(tty);
440 /* apply mtt override */
441 sir_tty_drv.qos_mtt_bits = qos_mtt_bits;
443 /* get a sir device instance for this driver */
444 dev = sirdev_get_instance(&sir_tty_drv, tty->name);
450 /* allocate private device info block */
451 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
457 priv->magic = IRTTY_MAGIC;
461 /* serialize with start_dev - in case we were racing with ifup */
462 mutex_lock(&irtty_mutex);
465 tty->disc_data = priv;
466 tty->receive_room = 65536;
468 mutex_unlock(&irtty_mutex);
470 pr_debug("%s - %s: irda line discipline opened\n", __func__, tty->name);
475 sirdev_put_instance(dev);
481 * Function irtty_close (tty)
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).
487 static void irtty_close(struct tty_struct *tty)
489 struct sirtty_cb *priv = tty->disc_data;
491 IRDA_ASSERT(priv != NULL, return;);
492 IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
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...
509 /* we are dead now */
510 tty->disc_data = NULL;
512 sirdev_put_instance(priv->dev);
515 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
521 pr_debug("%s - %s: irda line discipline closed\n", __func__, tty->name);
524 /* ------------------------------------------------------- */
526 static struct tty_ldisc_ops irda_ldisc = {
527 .magic = TTY_LDISC_MAGIC,
531 .close = irtty_close,
534 .ioctl = irtty_ioctl,
536 .receive_buf = irtty_receive_buf,
537 .write_wakeup = irtty_write_wakeup,
538 .owner = THIS_MODULE,
541 /* ------------------------------------------------------- */
543 static int __init irtty_sir_init(void)
547 if ((err = tty_register_ldisc(N_IRDA, &irda_ldisc)) != 0)
548 net_err_ratelimited("IrDA: can't register line discipline (err = %d)\n",
553 static void __exit irtty_sir_cleanup(void)
557 if ((err = tty_unregister_ldisc(N_IRDA))) {
558 net_err_ratelimited("%s(), can't unregister line discipline (err = %d)\n",
563 module_init(irtty_sir_init);
564 module_exit(irtty_sir_cleanup);
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");