drivers/net/irda/irtty-sir.c

   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/smp_lock.h>
  35 #include <linux/delay.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 priv->tty->driver->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->driver->wait_until_sent) {
  96                 lock_kernel();
  97                 tty->driver->wait_until_sent(tty, msecs_to_jiffies(100));
  98                 unlock_kernel();
  99         }
 100         else {
 101                 msleep(USBSERIAL_TX_DONE_DELAY);
 102         }
 103 }
 104
 105 /*
 106  *  Function irtty_change_speed (dev, speed)
 107  *
 108  *    Change the speed of the serial port.
 109  *
 110  * This may sleep in set_termios (usbserial driver f.e.) and must
 111  * not be called from interrupt/timer/tasklet therefore.
 112  * All such invocations are deferred to kIrDAd now so we can sleep there.
 113  */
 114
 115 static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
 116 {
 117         struct sirtty_cb *priv = dev->priv;
 118         struct tty_struct *tty;
 119         struct termios old_termios;
 120         int cflag;
 121
 122         IRDA_ASSERT(priv != NULL, return -1;);
 123         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
 124
 125         tty = priv->tty;
 126
 127         lock_kernel();
 128         old_termios = *(tty->termios);
 129         cflag = tty->termios->c_cflag;
 130
 131         cflag &= ~CBAUD;
 132
 133         IRDA_DEBUG(2, "%s(), Setting speed to %d\n", __FUNCTION__, speed);
 134
 135         switch (speed) {
 136         case 1200:
 137                 cflag |= B1200;
 138                 break;
 139         case 2400:
 140                 cflag |= B2400;
 141                 break;
 142         case 4800:
 143                 cflag |= B4800;
 144                 break;
 145         case 19200:
 146                 cflag |= B19200;
 147                 break;
 148         case 38400:
 149                 cflag |= B38400;
 150                 break;
 151         case 57600:
 152                 cflag |= B57600;
 153                 break;
 154         case 115200:
 155                 cflag |= B115200;
 156                 break;
 157         case 9600:
 158         default:
 159                 cflag |= B9600;
 160                 break;
 161         }
 162
 163         tty->termios->c_cflag = cflag;
 164         if (tty->driver->set_termios)
 165                 tty->driver->set_termios(tty, &old_termios);
 166         unlock_kernel();
 167
 168         priv->io.speed = speed;
 169
 170         return 0;
 171 }
 172
 173 /*
 174  * Function irtty_set_dtr_rts (dev, dtr, rts)
 175  *
 176  *    This function can be used by dongles etc. to set or reset the status
 177  *    of the dtr and rts lines
 178  */
 179
 180 static int irtty_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
 181 {
 182         struct sirtty_cb *priv = dev->priv;
 183         int set = 0;
 184         int clear = 0;
 185
 186         IRDA_ASSERT(priv != NULL, return -1;);
 187         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
 188
 189         if (rts)
 190                 set |= TIOCM_RTS;
 191         else
 192                 clear |= TIOCM_RTS;
 193         if (dtr)
 194                 set |= TIOCM_DTR;
 195         else
 196                 clear |= TIOCM_DTR;
 197
 198         /*
 199          * We can't use ioctl() because it expects a non-null file structure,
 200          * and we don't have that here.
 201          * This function is not yet defined for all tty driver, so
 202          * let's be careful... Jean II
 203          */
 204         IRDA_ASSERT(priv->tty->driver->tiocmset != NULL, return -1;);
 205         priv->tty->driver->tiocmset(priv->tty, NULL, set, clear);
 206
 207         return 0;
 208 }
 209
 210 /* ------------------------------------------------------- */
 211
 212 /* called from sir_dev when there is more data to send
 213  * context is either netdev->hard_xmit or some transmit-completion bh
 214  * i.e. we are under spinlock here and must not sleep.
 215  */
 216
 217 static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t len)
 218 {
 219         struct sirtty_cb *priv = dev->priv;
 220         struct tty_struct *tty;
 221         int writelen;
 222
 223         IRDA_ASSERT(priv != NULL, return -1;);
 224         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
 225
 226         tty = priv->tty;
 227         if (!tty->driver->write)
 228                 return 0;
 229         tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
 230         if (tty->driver->write_room) {
 231                 writelen = tty->driver->write_room(tty);
 232                 if (writelen > len)
 233                         writelen = len;
 234         }
 235         else
 236                 writelen = len;
 237         return tty->driver->write(tty, ptr, writelen);
 238 }
 239
 240 /* ------------------------------------------------------- */
 241
 242 /* irda line discipline callbacks */
 243
 244 /*
 245  *  Function irtty_receive_buf( tty, cp, count)
 246  *
 247  *    Handle the 'receiver data ready' interrupt.  This function is called
 248  *    by the 'tty_io' module in the kernel when a block of IrDA data has
 249  *    been received, which can now be decapsulated and delivered for
 250  *    further processing
 251  *
 252  * calling context depends on underlying driver and tty->low_latency!
 253  * for example (low_latency: 1 / 0):
 254  * serial.c:    uart-interrupt / softint
 255  * usbserial:   urb-complete-interrupt / softint
 256  */
 257
 258 static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 259                               char *fp, int count)
 260 {
 261         struct sir_dev *dev;
 262         struct sirtty_cb *priv = tty->disc_data;
 263         int     i;
 264
 265         IRDA_ASSERT(priv != NULL, return;);
 266         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
 267
 268         if (unlikely(count==0))         /* yes, this happens */
 269                 return;
 270
 271         dev = priv->dev;
 272         if (!dev) {
 273                 IRDA_WARNING("%s(), not ready yet!\n", __FUNCTION__);
 274                 return;
 275         }
 276
 277         for (i = 0; i < count; i++) {
 278                 /*
 279                  *  Characters received with a parity error, etc?
 280                  */
 281                 if (fp && *fp++) {
 282                         IRDA_DEBUG(0, "Framing or parity error!\n");
 283                         sirdev_receive(dev, NULL, 0);   /* notify sir_dev (updating stats) */
 284                         return;
 285                 }
 286         }
 287
 288         sirdev_receive(dev, cp, count);
 289 }
 290
 291 /*
 292  * Function irtty_write_wakeup (tty)
 293  *
 294  *    Called by the driver when there's room for more data.  If we have
 295  *    more packets to send, we send them here.
 296  *
 297  */
 298 static void irtty_write_wakeup(struct tty_struct *tty)
 299 {
 300         struct sirtty_cb *priv = tty->disc_data;
 301
 302         IRDA_ASSERT(priv != NULL, return;);
 303         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
 304
 305         tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 306
 307         if (priv->dev)
 308                 sirdev_write_complete(priv->dev);
 309 }
 310
 311 /* ------------------------------------------------------- */
 312
 313 /*
 314  * Function irtty_stop_receiver (tty, stop)
 315  *
 316  */
 317
 318 static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
 319 {
 320         struct termios old_termios;
 321         int cflag;
 322
 323         lock_kernel();
 324         old_termios = *(tty->termios);
 325         cflag = tty->termios->c_cflag;
 326
 327         if (stop)
 328                 cflag &= ~CREAD;
 329         else
 330                 cflag |= CREAD;
 331
 332         tty->termios->c_cflag = cflag;
 333         if (tty->driver->set_termios)
 334                 tty->driver->set_termios(tty, &old_termios);
 335         unlock_kernel();
 336 }
 337
 338 /*****************************************************************/
 339
 340 /* serialize ldisc open/close with sir_dev */
 341 static DECLARE_MUTEX(irtty_sem);
 342
 343 /* notifier from sir_dev when irda% device gets opened (ifup) */
 344
 345 static int irtty_start_dev(struct sir_dev *dev)
 346 {
 347         struct sirtty_cb *priv;
 348         struct tty_struct *tty;
 349
 350         /* serialize with ldisc open/close */
 351         down(&irtty_sem);
 352
 353         priv = dev->priv;
 354         if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
 355                 up(&irtty_sem);
 356                 return -ESTALE;
 357         }
 358
 359         tty = priv->tty;
 360
 361         if (tty->driver->start)
 362                 tty->driver->start(tty);
 363         /* Make sure we can receive more data */
 364         irtty_stop_receiver(tty, FALSE);
 365
 366         up(&irtty_sem);
 367         return 0;
 368 }
 369
 370 /* notifier from sir_dev when irda% device gets closed (ifdown) */
 371
 372 static int irtty_stop_dev(struct sir_dev *dev)
 373 {
 374         struct sirtty_cb *priv;
 375         struct tty_struct *tty;
 376
 377         /* serialize with ldisc open/close */
 378         down(&irtty_sem);
 379
 380         priv = dev->priv;
 381         if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
 382                 up(&irtty_sem);
 383                 return -ESTALE;
 384         }
 385
 386         tty = priv->tty;
 387
 388         /* Make sure we don't receive more data */
 389         irtty_stop_receiver(tty, TRUE);
 390         if (tty->driver->stop)
 391                 tty->driver->stop(tty);
 392
 393         up(&irtty_sem);
 394
 395         return 0;
 396 }
 397
 398 /* ------------------------------------------------------- */
 399
 400 static struct sir_driver sir_tty_drv = {
 401         .owner                  = THIS_MODULE,
 402         .driver_name            = "sir_tty",
 403         .start_dev              = irtty_start_dev,
 404         .stop_dev               = irtty_stop_dev,
 405         .do_write               = irtty_do_write,
 406         .chars_in_buffer        = irtty_chars_in_buffer,
 407         .wait_until_sent        = irtty_wait_until_sent,
 408         .set_speed              = irtty_change_speed,
 409         .set_dtr_rts            = irtty_set_dtr_rts,
 410 };
 411
 412 /* ------------------------------------------------------- */
 413
 414 /*
 415  * Function irtty_ioctl (tty, file, cmd, arg)
 416  *
 417  *     The Swiss army knife of system calls :-)
 418  *
 419  */
 420 static int irtty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
 421 {
 422         struct irtty_info { char name[6]; } info;
 423         struct sir_dev *dev;
 424         struct sirtty_cb *priv = tty->disc_data;
 425         int err = 0;
 426
 427         IRDA_ASSERT(priv != NULL, return -ENODEV;);
 428         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EBADR;);
 429
 430         IRDA_DEBUG(3, "%s(cmd=0x%X)\n", __FUNCTION__, cmd);
 431
 432         dev = priv->dev;
 433         IRDA_ASSERT(dev != NULL, return -1;);
 434
 435         switch (cmd) {
 436         case TCGETS:
 437         case TCGETA:
 438                 err = n_tty_ioctl(tty, file, cmd, arg);
 439                 break;
 440
 441         case IRTTY_IOCTDONGLE:
 442                 /* this call blocks for completion */
 443                 err = sirdev_set_dongle(dev, (IRDA_DONGLE) arg);
 444                 break;
 445
 446         case IRTTY_IOCGET:
 447                 IRDA_ASSERT(dev->netdev != NULL, return -1;);
 448
 449                 memset(&info, 0, sizeof(info));
 450                 strncpy(info.name, dev->netdev->name, sizeof(info.name)-1);
 451
 452                 if (copy_to_user((void __user *)arg, &info, sizeof(info)))
 453                         err = -EFAULT;
 454                 break;
 455         default:
 456                 err = -ENOIOCTLCMD;
 457                 break;
 458         }
 459         return err;
 460 }
 461
 462
 463 /*
 464  *  Function irtty_open(tty)
 465  *
 466  *    This function is called by the TTY module when the IrDA line
 467  *    discipline is called for.  Because we are sure the tty line exists,
 468  *    we only have to link it to a free IrDA channel.
 469  */
 470 static int irtty_open(struct tty_struct *tty)
 471 {
 472         struct sir_dev *dev;
 473         struct sirtty_cb *priv;
 474         int ret = 0;
 475
 476         /* Module stuff handled via irda_ldisc.owner - Jean II */
 477
 478         /* First make sure we're not already connected. */
 479         if (tty->disc_data != NULL) {
 480                 priv = tty->disc_data;
 481                 if (priv && priv->magic == IRTTY_MAGIC) {
 482                         ret = -EEXIST;
 483                         goto out;
 484                 }
 485                 tty->disc_data = NULL;          /* ### */
 486         }
 487
 488         /* stop the underlying  driver */
 489         irtty_stop_receiver(tty, TRUE);
 490         if (tty->driver->stop)
 491                 tty->driver->stop(tty);
 492
 493         if (tty->driver->flush_buffer)
 494                 tty->driver->flush_buffer(tty);
 495
 496         /* apply mtt override */
 497         sir_tty_drv.qos_mtt_bits = qos_mtt_bits;
 498
 499         /* get a sir device instance for this driver */
 500         dev = sirdev_get_instance(&sir_tty_drv, tty->name);
 501         if (!dev) {
 502                 ret = -ENODEV;
 503                 goto out;
 504         }
 505
 506         /* allocate private device info block */
 507         priv = kmalloc(sizeof(*priv), GFP_KERNEL);
 508         if (!priv)
 509                 goto out_put;
 510         memset(priv, 0, sizeof(*priv));
 511
 512         priv->magic = IRTTY_MAGIC;
 513         priv->tty = tty;
 514         priv->dev = dev;
 515
 516         /* serialize with start_dev - in case we were racing with ifup */
 517         down(&irtty_sem);
 518
 519         dev->priv = priv;
 520         tty->disc_data = priv;
 521         tty->receive_room = 65536;
 522
 523         up(&irtty_sem);
 524
 525         IRDA_DEBUG(0, "%s - %s: irda line discipline opened\n", __FUNCTION__, tty->name);
 526
 527         return 0;
 528
 529 out_put:
 530         sirdev_put_instance(dev);
 531 out:
 532         return ret;
 533 }
 534
 535 /*
 536  *  Function irtty_close (tty)
 537  *
 538  *    Close down a IrDA channel. This means flushing out any pending queues,
 539  *    and then restoring the TTY line discipline to what it was before it got
 540  *    hooked to IrDA (which usually is TTY again).
 541  */
 542 static void irtty_close(struct tty_struct *tty)
 543 {
 544         struct sirtty_cb *priv = tty->disc_data;
 545
 546         IRDA_ASSERT(priv != NULL, return;);
 547         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
 548
 549         /* Hm, with a dongle attached the dongle driver wants
 550          * to close the dongle - which requires the use of
 551          * some tty write and/or termios or ioctl operations.
 552          * Are we allowed to call those when already requested
 553          * to shutdown the ldisc?
 554          * If not, we should somehow mark the dev being staled.
 555          * Question remains, how to close the dongle in this case...
 556          * For now let's assume we are granted to issue tty driver calls
 557          * until we return here from the ldisc close. I'm just wondering
 558          * how this behaves with hotpluggable serial hardware like
 559          * rs232-pcmcia card or usb-serial...
 560          *
 561          * priv->tty = NULL?;
 562          */
 563
 564         /* we are dead now */
 565         tty->disc_data = NULL;
 566
 567         sirdev_put_instance(priv->dev);
 568
 569         /* Stop tty */
 570         irtty_stop_receiver(tty, TRUE);
 571         tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 572         if (tty->driver->stop)
 573                 tty->driver->stop(tty);
 574
 575         kfree(priv);
 576
 577         IRDA_DEBUG(0, "%s - %s: irda line discipline closed\n", __FUNCTION__, tty->name);
 578 }
 579
 580 /* ------------------------------------------------------- */
 581
 582 static struct tty_ldisc irda_ldisc = {
 583         .magic          = TTY_LDISC_MAGIC,
 584         .name           = "irda",
 585         .flags          = 0,
 586         .open           = irtty_open,
 587         .close          = irtty_close,
 588         .read           = NULL,
 589         .write          = NULL,
 590         .ioctl          = irtty_ioctl,
 591         .poll           = NULL,
 592         .receive_buf    = irtty_receive_buf,
 593         .write_wakeup   = irtty_write_wakeup,
 594         .owner          = THIS_MODULE,
 595 };
 596
 597 /* ------------------------------------------------------- */
 598
 599 static int __init irtty_sir_init(void)
 600 {
 601         int err;
 602
 603         if ((err = tty_register_ldisc(N_IRDA, &irda_ldisc)) != 0)
 604                 IRDA_ERROR("IrDA: can't register line discipline (err = %d)\n",
 605                            err);
 606         return err;
 607 }
 608
 609 static void __exit irtty_sir_cleanup(void)
 610 {
 611         int err;
 612
 613         if ((err = tty_unregister_ldisc(N_IRDA))) {
 614                 IRDA_ERROR("%s(), can't unregister line discipline (err = %d)\n",
 615                            __FUNCTION__, err);
 616         }
 617 }
 618
 619 module_init(irtty_sir_init);
 620 module_exit(irtty_sir_cleanup);
 621
 622 MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
 623 MODULE_DESCRIPTION("IrDA TTY device driver");
 624 MODULE_ALIAS_LDISC(N_IRDA);
 625 MODULE_LICENSE("GPL");
 626