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 mutex_lock(&tty
->termios_mutex
);
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 mutex_unlock(&tty
->termios_mutex
);
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
, NULL
, 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->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 IRDA_WARNING("%s(), not ready yet!\n", __func__
);
238 for (i
= 0; i
< count
; i
++) {
240 * Characters received with a parity error, etc?
243 IRDA_DEBUG(0, "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 mutex_lock(&tty
->termios_mutex
);
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 mutex_unlock(&tty
->termios_mutex
);
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 IRDA_DEBUG(3, "%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 /* First make sure we're not already connected. */
434 if (tty
->disc_data
!= NULL
) {
435 priv
= tty
->disc_data
;
436 if (priv
&& priv
->magic
== IRTTY_MAGIC
) {
440 tty
->disc_data
= NULL
; /* ### */
443 /* stop the underlying driver */
444 irtty_stop_receiver(tty
, TRUE
);
448 tty_driver_flush_buffer(tty
);
450 /* apply mtt override */
451 sir_tty_drv
.qos_mtt_bits
= qos_mtt_bits
;
453 /* get a sir device instance for this driver */
454 dev
= sirdev_get_instance(&sir_tty_drv
, tty
->name
);
460 /* allocate private device info block */
461 priv
= kzalloc(sizeof(*priv
), GFP_KERNEL
);
465 priv
->magic
= IRTTY_MAGIC
;
469 /* serialize with start_dev - in case we were racing with ifup */
470 mutex_lock(&irtty_mutex
);
473 tty
->disc_data
= priv
;
474 tty
->receive_room
= 65536;
476 mutex_unlock(&irtty_mutex
);
478 IRDA_DEBUG(0, "%s - %s: irda line discipline opened\n", __func__
, tty
->name
);
483 sirdev_put_instance(dev
);
489 * Function irtty_close (tty)
491 * Close down a IrDA channel. This means flushing out any pending queues,
492 * and then restoring the TTY line discipline to what it was before it got
493 * hooked to IrDA (which usually is TTY again).
495 static void irtty_close(struct tty_struct
*tty
)
497 struct sirtty_cb
*priv
= tty
->disc_data
;
499 IRDA_ASSERT(priv
!= NULL
, return;);
500 IRDA_ASSERT(priv
->magic
== IRTTY_MAGIC
, return;);
502 /* Hm, with a dongle attached the dongle driver wants
503 * to close the dongle - which requires the use of
504 * some tty write and/or termios or ioctl operations.
505 * Are we allowed to call those when already requested
506 * to shutdown the ldisc?
507 * If not, we should somehow mark the dev being staled.
508 * Question remains, how to close the dongle in this case...
509 * For now let's assume we are granted to issue tty driver calls
510 * until we return here from the ldisc close. I'm just wondering
511 * how this behaves with hotpluggable serial hardware like
512 * rs232-pcmcia card or usb-serial...
517 /* we are dead now */
518 tty
->disc_data
= NULL
;
520 sirdev_put_instance(priv
->dev
);
523 irtty_stop_receiver(tty
, TRUE
);
524 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
530 IRDA_DEBUG(0, "%s - %s: irda line discipline closed\n", __func__
, tty
->name
);
533 /* ------------------------------------------------------- */
535 static struct tty_ldisc_ops irda_ldisc
= {
536 .magic
= TTY_LDISC_MAGIC
,
540 .close
= irtty_close
,
543 .ioctl
= irtty_ioctl
,
545 .receive_buf
= irtty_receive_buf
,
546 .write_wakeup
= irtty_write_wakeup
,
547 .owner
= THIS_MODULE
,
550 /* ------------------------------------------------------- */
552 static int __init
irtty_sir_init(void)
556 if ((err
= tty_register_ldisc(N_IRDA
, &irda_ldisc
)) != 0)
557 IRDA_ERROR("IrDA: can't register line discipline (err = %d)\n",
562 static void __exit
irtty_sir_cleanup(void)
566 if ((err
= tty_unregister_ldisc(N_IRDA
))) {
567 IRDA_ERROR("%s(), can't unregister line discipline (err = %d)\n",
572 module_init(irtty_sir_init
);
573 module_exit(irtty_sir_cleanup
);
575 MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
576 MODULE_DESCRIPTION("IrDA TTY device driver");
577 MODULE_ALIAS_LDISC(N_IRDA
);
578 MODULE_LICENSE("GPL");
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