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
  36 #include <net/irda/irda.h>
  37 #include <net/irda/irda_device.h>
  38
  39 #include "sir-dev.h"
  40 #include "irtty-sir.h"
  41
  42 MODULE_PARM(qos_mtt_bits, "i");
  43 MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
  44
  45 static int qos_mtt_bits = 0x03;      /* 5 ms or more */
  46
  47 /* ------------------------------------------------------- */
  48
  49 /* device configuration callbacks always invoked with irda-thread context */
  50
  51 /* find out, how many chars we have in buffers below us
  52  * this is allowed to lie, i.e. return less chars than we
  53  * actually have. The returned value is used to determine
  54  * how long the irdathread should wait before doing the
  55  * real blocking wait_until_sent()
  56  */
  57
  58 static int irtty_chars_in_buffer(struct sir_dev *dev)
  59 {
  60         struct sirtty_cb *priv = dev->priv;
  61
  62         ASSERT(priv != NULL, return -1;);
  63         ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
  64
  65         return priv->tty->driver->chars_in_buffer(priv->tty);
  66 }
  67
  68 /* Wait (sleep) until underlaying hardware finished transmission
  69  * i.e. hardware buffers are drained
  70  * this must block and not return before all characters are really sent
  71  *
  72  * If the tty sits on top of a 16550A-like uart, there are typically
  73  * up to 16 bytes in the fifo - f.e. 9600 bps 8N1 needs 16.7 msec
  74  *
  75  * With usbserial the uart-fifo is basically replaced by the converter's
  76  * outgoing endpoint buffer, which can usually hold 64 bytes (at least).
  77  * With pl2303 it appears we are safe with 60msec here.
  78  *
  79  * I really wish all serial drivers would provide
  80  * correct implementation of wait_until_sent()
  81  */
  82
  83 #define USBSERIAL_TX_DONE_DELAY 60
  84
  85 static void irtty_wait_until_sent(struct sir_dev *dev)
  86 {
  87         struct sirtty_cb *priv = dev->priv;
  88         struct tty_struct *tty;
  89
  90         ASSERT(priv != NULL, return;);
  91         ASSERT(priv->magic == IRTTY_MAGIC, return;);
  92
  93         tty = priv->tty;
  94         if (tty->driver->wait_until_sent) {
  95                 lock_kernel();
  96                 tty->driver->wait_until_sent(tty, msecs_to_jiffies(100));
  97                 unlock_kernel();
  98         }
  99         else {
 100                 set_task_state(current, TASK_UNINTERRUPTIBLE);
 101                 schedule_timeout(msecs_to_jiffies(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         ASSERT(priv != NULL, return -1;);
 123         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         ASSERT(priv != NULL, return -1;);
 187         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         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         ASSERT(priv != NULL, return -1;);
 224         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, 0, 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         ASSERT(priv != NULL, return;);
 266         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                 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_receive_room (tty)
 293  *
 294  *    Used by the TTY to find out how much data we can receive at a time
 295  *
 296 */
 297 static int irtty_receive_room(struct tty_struct *tty)
 298 {
 299         struct sirtty_cb *priv = tty->disc_data;
 300
 301         ASSERT(priv != NULL, return 0;);
 302         ASSERT(priv->magic == IRTTY_MAGIC, return 0;);
 303
 304         return 65536;  /* We can handle an infinite amount of data. :-) */
 305 }
 306
 307 /*
 308  * Function irtty_write_wakeup (tty)
 309  *
 310  *    Called by the driver when there's room for more data.  If we have
 311  *    more packets to send, we send them here.
 312  *
 313  */
 314 static void irtty_write_wakeup(struct tty_struct *tty)
 315 {
 316         struct sirtty_cb *priv = tty->disc_data;
 317
 318         ASSERT(priv != NULL, return;);
 319         ASSERT(priv->magic == IRTTY_MAGIC, return;);
 320
 321         tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 322
 323         if (priv->dev)
 324                 sirdev_write_complete(priv->dev);
 325 }
 326
 327 /* ------------------------------------------------------- */
 328
 329 /*
 330  * Function irtty_stop_receiver (tty, stop)
 331  *
 332  */
 333
 334 static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
 335 {
 336         struct termios old_termios;
 337         int cflag;
 338
 339         lock_kernel();
 340         old_termios = *(tty->termios);
 341         cflag = tty->termios->c_cflag;
 342
 343         if (stop)
 344                 cflag &= ~CREAD;
 345         else
 346                 cflag |= CREAD;
 347
 348         tty->termios->c_cflag = cflag;
 349         if (tty->driver->set_termios)
 350                 tty->driver->set_termios(tty, &old_termios);
 351         unlock_kernel();
 352 }
 353
 354 /*****************************************************************/
 355
 356 /* serialize ldisc open/close with sir_dev */
 357 static DECLARE_MUTEX(irtty_sem);
 358
 359 /* notifier from sir_dev when irda% device gets opened (ifup) */
 360
 361 static int irtty_start_dev(struct sir_dev *dev)
 362 {
 363         struct sirtty_cb *priv;
 364         struct tty_struct *tty;
 365
 366         /* serialize with ldisc open/close */
 367         down(&irtty_sem);
 368
 369         priv = dev->priv;
 370         if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
 371                 up(&irtty_sem);
 372                 return -ESTALE;
 373         }
 374
 375         tty = priv->tty;
 376
 377         if (tty->driver->start)
 378                 tty->driver->start(tty);
 379         /* Make sure we can receive more data */
 380         irtty_stop_receiver(tty, FALSE);
 381
 382         up(&irtty_sem);
 383         return 0;
 384 }
 385
 386 /* notifier from sir_dev when irda% device gets closed (ifdown) */
 387
 388 static int irtty_stop_dev(struct sir_dev *dev)
 389 {
 390         struct sirtty_cb *priv;
 391         struct tty_struct *tty;
 392
 393         /* serialize with ldisc open/close */
 394         down(&irtty_sem);
 395
 396         priv = dev->priv;
 397         if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
 398                 up(&irtty_sem);
 399                 return -ESTALE;
 400         }
 401
 402         tty = priv->tty;
 403
 404         /* Make sure we don't receive more data */
 405         irtty_stop_receiver(tty, TRUE);
 406         if (tty->driver->stop)
 407                 tty->driver->stop(tty);
 408
 409         up(&irtty_sem);
 410
 411         return 0;
 412 }
 413
 414 /* ------------------------------------------------------- */
 415
 416 struct sir_driver sir_tty_drv = {
 417         .owner                  = THIS_MODULE,
 418         .driver_name            = "sir_tty",
 419         .start_dev              = irtty_start_dev,
 420         .stop_dev               = irtty_stop_dev,
 421         .do_write               = irtty_do_write,
 422         .chars_in_buffer        = irtty_chars_in_buffer,
 423         .wait_until_sent        = irtty_wait_until_sent,
 424         .set_speed              = irtty_change_speed,
 425         .set_dtr_rts            = irtty_set_dtr_rts,
 426 };
 427
 428 /* ------------------------------------------------------- */
 429
 430 /*
 431  * Function irtty_ioctl (tty, file, cmd, arg)
 432  *
 433  *     The Swiss army knife of system calls :-)
 434  *
 435  */
 436 static int irtty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
 437 {
 438         struct irtty_info { char name[6]; } info;
 439         struct sir_dev *dev;
 440         struct sirtty_cb *priv = tty->disc_data;
 441         int size = _IOC_SIZE(cmd);
 442         int err = 0;
 443
 444         ASSERT(priv != NULL, return -ENODEV;);
 445         ASSERT(priv->magic == IRTTY_MAGIC, return -EBADR;);
 446
 447         IRDA_DEBUG(3, "%s(cmd=0x%X)\n", __FUNCTION__, cmd);
 448
 449         dev = priv->dev;
 450         ASSERT(dev != NULL, return -1;);
 451
 452         if (_IOC_DIR(cmd) & _IOC_READ)
 453                 err = verify_area(VERIFY_WRITE, (void *) arg, size);
 454         else if (_IOC_DIR(cmd) & _IOC_WRITE)
 455                 err = verify_area(VERIFY_READ, (void *) arg, size);
 456         if (err)
 457                 return err;
 458
 459         switch (cmd) {
 460         case TCGETS:
 461         case TCGETA:
 462                 err = n_tty_ioctl(tty, file, cmd, arg);
 463                 break;
 464
 465         case IRTTY_IOCTDONGLE:
 466                 /* this call blocks for completion */
 467                 err = sirdev_set_dongle(dev, (IRDA_DONGLE) arg);
 468                 break;
 469
 470         case IRTTY_IOCGET:
 471                 ASSERT(dev->netdev != NULL, return -1;);
 472
 473                 memset(&info, 0, sizeof(info));
 474                 strncpy(info.name, dev->netdev->name, sizeof(info.name)-1);
 475
 476                 if (copy_to_user((void *)arg, &info, sizeof(info)))
 477                         err = -EFAULT;
 478                 break;
 479         default:
 480                 err = -ENOIOCTLCMD;
 481                 break;
 482         }
 483         return err;
 484 }
 485
 486
 487 /*
 488  *  Function irtty_open(tty)
 489  *
 490  *    This function is called by the TTY module when the IrDA line
 491  *    discipline is called for.  Because we are sure the tty line exists,
 492  *    we only have to link it to a free IrDA channel.
 493  */
 494 static int irtty_open(struct tty_struct *tty)
 495 {
 496         struct sir_dev *dev;
 497         struct sirtty_cb *priv;
 498         int ret = 0;
 499
 500         /* Module stuff handled via irda_ldisc.owner - Jean II */
 501
 502         /* First make sure we're not already connected. */
 503         if (tty->disc_data != NULL) {
 504                 priv = tty->disc_data;
 505                 if (priv && priv->magic == IRTTY_MAGIC) {
 506                         ret = -EEXIST;
 507                         goto out;
 508                 }
 509                 tty->disc_data = NULL;          /* ### */
 510         }
 511
 512         /* stop the underlying  driver */
 513         irtty_stop_receiver(tty, TRUE);
 514         if (tty->driver->stop)
 515                 tty->driver->stop(tty);
 516
 517         if (tty->driver->flush_buffer)
 518                 tty->driver->flush_buffer(tty);
 519
 520 /* from old irtty - but what is it good for?
 521  * we _are_ the ldisc and we _don't_ implement flush_buffer!
 522  *
 523  *      if (tty->ldisc.flush_buffer)
 524  *              tty->ldisc.flush_buffer(tty);
 525  */
 526
 527         /* apply mtt override */
 528         sir_tty_drv.qos_mtt_bits = qos_mtt_bits;
 529
 530         /* get a sir device instance for this driver */
 531         dev = sirdev_get_instance(&sir_tty_drv, tty->name);
 532         if (!dev) {
 533                 ret = -ENODEV;
 534                 goto out;
 535         }
 536
 537         /* allocate private device info block */
 538         priv = kmalloc(sizeof(*priv), GFP_KERNEL);
 539         if (!priv)
 540                 goto out_put;
 541         memset(priv, 0, sizeof(*priv));
 542
 543         priv->magic = IRTTY_MAGIC;
 544         priv->tty = tty;
 545         priv->dev = dev;
 546
 547         /* serialize with start_dev - in case we were racing with ifup */
 548         down(&irtty_sem);
 549
 550         dev->priv = priv;
 551         tty->disc_data = priv;
 552
 553         up(&irtty_sem);
 554
 555         IRDA_DEBUG(0, "%s - %s: irda line discipline opened\n", __FUNCTION__, tty->name);
 556
 557         return 0;
 558
 559 out_put:
 560         sirdev_put_instance(dev);
 561 out:
 562         return ret;
 563 }
 564
 565 /*
 566  *  Function irtty_close (tty)
 567  *
 568  *    Close down a IrDA channel. This means flushing out any pending queues,
 569  *    and then restoring the TTY line discipline to what it was before it got
 570  *    hooked to IrDA (which usually is TTY again).
 571  */
 572 static void irtty_close(struct tty_struct *tty)
 573 {
 574         struct sirtty_cb *priv = tty->disc_data;
 575
 576         ASSERT(priv != NULL, return;);
 577         ASSERT(priv->magic == IRTTY_MAGIC, return;);
 578
 579         /* Hm, with a dongle attached the dongle driver wants
 580          * to close the dongle - which requires the use of
 581          * some tty write and/or termios or ioctl operations.
 582          * Are we allowed to call those when already requested
 583          * to shutdown the ldisc?
 584          * If not, we should somehow mark the dev being staled.
 585          * Question remains, how to close the dongle in this case...
 586          * For now let's assume we are granted to issue tty driver calls
 587          * until we return here from the ldisc close. I'm just wondering
 588          * how this behaves with hotpluggable serial hardware like
 589          * rs232-pcmcia card or usb-serial...
 590          *
 591          * priv->tty = NULL?;
 592          */
 593
 594         /* we are dead now */
 595         tty->disc_data = 0;
 596
 597         sirdev_put_instance(priv->dev);
 598
 599         /* Stop tty */
 600         irtty_stop_receiver(tty, TRUE);
 601         tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
 602         if (tty->driver->stop)
 603                 tty->driver->stop(tty);
 604
 605         kfree(priv);
 606
 607         IRDA_DEBUG(0, "%s - %s: irda line discipline closed\n", __FUNCTION__, tty->name);
 608 }
 609
 610 /* ------------------------------------------------------- */
 611
 612 static struct tty_ldisc irda_ldisc = {
 613         .magic          = TTY_LDISC_MAGIC,
 614         .name           = "irda",
 615         .flags          = 0,
 616         .open           = irtty_open,
 617         .close          = irtty_close,
 618         .read           = NULL,
 619         .write          = NULL,
 620         .ioctl          = irtty_ioctl,
 621         .poll           = NULL,
 622         .receive_buf    = irtty_receive_buf,
 623         .receive_room   = irtty_receive_room,
 624         .write_wakeup   = irtty_write_wakeup,
 625         .owner          = THIS_MODULE,
 626 };
 627
 628 /* ------------------------------------------------------- */
 629
 630 static int __init irtty_sir_init(void)
 631 {
 632         int err;
 633
 634         if ((err = tty_register_ldisc(N_IRDA, &irda_ldisc)) != 0)
 635                 ERROR("IrDA: can't register line discipline (err = %d)\n",
 636                         err);
 637         return err;
 638 }
 639
 640 static void __exit irtty_sir_cleanup(void)
 641 {
 642         int err;
 643
 644         if ((err = tty_register_ldisc(N_IRDA, NULL))) {
 645                 ERROR("%s(), can't unregister line discipline (err = %d)\n",
 646                       __FUNCTION__, err);
 647         }
 648 }
 649
 650 module_init(irtty_sir_init);
 651 module_exit(irtty_sir_cleanup);
 652
 653 MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
 654 MODULE_DESCRIPTION("IrDA TTY device driver");
 655 MODULE_ALIAS_LDISC(N_IRDA);
 656 MODULE_LICENSE("GPL");
 657