drivers/isdn/gigaset/ser-gigaset.c

   1 /* This is the serial hardware link layer (HLL) for the Gigaset 307x isdn
   2  * DECT base (aka Sinus 45 isdn) using the RS232 DECT data module M101,
   3  * written as a line discipline.
   4  *
   5  * =====================================================================
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of
   9  * the License, or (at your option) any later version.
  10  * =====================================================================
  11  */
  12
  13 #include "gigaset.h"
  14 #include <linux/module.h>
  15 #include <linux/moduleparam.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/completion.h>
  18
  19 /* Version Information */
  20 #define DRIVER_AUTHOR "Tilman Schmidt"
  21 #define DRIVER_DESC "Serial Driver for Gigaset 307x using Siemens M101"
  22
  23 #define GIGASET_MINORS     1
  24 #define GIGASET_MINOR      0
  25 #define GIGASET_MODULENAME "ser_gigaset"
  26 #define GIGASET_DEVNAME    "ttyGS"
  27
  28 /* length limit according to Siemens 3070usb-protokoll.doc ch. 2.1 */
  29 #define IF_WRITEBUF 264
  30
  31 MODULE_AUTHOR(DRIVER_AUTHOR);
  32 MODULE_DESCRIPTION(DRIVER_DESC);
  33 MODULE_LICENSE("GPL");
  34 MODULE_ALIAS_LDISC(N_GIGASET_M101);
  35
  36 static int startmode = SM_ISDN;
  37 module_param(startmode, int, S_IRUGO);
  38 MODULE_PARM_DESC(startmode, "initial operation mode");
  39 static int cidmode = 1;
  40 module_param(cidmode, int, S_IRUGO);
  41 MODULE_PARM_DESC(cidmode, "stay in CID mode when idle");
  42
  43 static struct gigaset_driver *driver;
  44
  45 struct ser_cardstate {
  46         struct platform_device  dev;
  47         struct tty_struct       *tty;
  48         atomic_t                refcnt;
  49         struct completion       dead_cmp;
  50 };
  51
  52 static struct platform_driver device_driver = {
  53         .driver = {
  54                 .name = GIGASET_MODULENAME,
  55         },
  56 };
  57
  58 static void flush_send_queue(struct cardstate *);
  59
  60 /* transmit data from current open skb
  61  * result: number of bytes sent or error code < 0
  62  */
  63 static int write_modem(struct cardstate *cs)
  64 {
  65         struct tty_struct *tty = cs->hw.ser->tty;
  66         struct bc_state *bcs = &cs->bcs[0];     /* only one channel */
  67         struct sk_buff *skb = bcs->tx_skb;
  68         int sent = -EOPNOTSUPP;
  69
  70         WARN_ON(!tty || !tty->ops || !skb);
  71
  72         if (!skb->len) {
  73                 dev_kfree_skb_any(skb);
  74                 bcs->tx_skb = NULL;
  75                 return -EINVAL;
  76         }
  77
  78         set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
  79         if (tty->ops->write)
  80                 sent = tty->ops->write(tty, skb->data, skb->len);
  81         gig_dbg(DEBUG_OUTPUT, "write_modem: sent %d", sent);
  82         if (sent < 0) {
  83                 /* error */
  84                 flush_send_queue(cs);
  85                 return sent;
  86         }
  87         skb_pull(skb, sent);
  88         if (!skb->len) {
  89                 /* skb sent completely */
  90                 gigaset_skb_sent(bcs, skb);
  91
  92                 gig_dbg(DEBUG_INTR, "kfree skb (Adr: %lx)!",
  93                         (unsigned long) skb);
  94                 dev_kfree_skb_any(skb);
  95                 bcs->tx_skb = NULL;
  96         }
  97         return sent;
  98 }
  99
 100 /*
 101  * transmit first queued command buffer
 102  * result: number of bytes sent or error code < 0
 103  */
 104 static int send_cb(struct cardstate *cs)
 105 {
 106         struct tty_struct *tty = cs->hw.ser->tty;
 107         struct cmdbuf_t *cb, *tcb;
 108         unsigned long flags;
 109         int sent = 0;
 110
 111         WARN_ON(!tty || !tty->ops);
 112
 113         cb = cs->cmdbuf;
 114         if (!cb)
 115                 return 0;       /* nothing to do */
 116
 117         if (cb->len) {
 118                 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 119                 sent = tty->ops->write(tty, cb->buf + cb->offset, cb->len);
 120                 if (sent < 0) {
 121                         /* error */
 122                         gig_dbg(DEBUG_OUTPUT, "send_cb: write error %d", sent);
 123                         flush_send_queue(cs);
 124                         return sent;
 125                 }
 126                 cb->offset += sent;
 127                 cb->len -= sent;
 128                 gig_dbg(DEBUG_OUTPUT, "send_cb: sent %d, left %u, queued %u",
 129                         sent, cb->len, cs->cmdbytes);
 130         }
 131
 132         while (cb && !cb->len) {
 133                 spin_lock_irqsave(&cs->cmdlock, flags);
 134                 cs->cmdbytes -= cs->curlen;
 135                 tcb = cb;
 136                 cs->cmdbuf = cb = cb->next;
 137                 if (cb) {
 138                         cb->prev = NULL;
 139                         cs->curlen = cb->len;
 140                 } else {
 141                         cs->lastcmdbuf = NULL;
 142                         cs->curlen = 0;
 143                 }
 144                 spin_unlock_irqrestore(&cs->cmdlock, flags);
 145
 146                 if (tcb->wake_tasklet)
 147                         tasklet_schedule(tcb->wake_tasklet);
 148                 kfree(tcb);
 149         }
 150         return sent;
 151 }
 152
 153 /*
 154  * send queue tasklet
 155  * If there is already a skb opened, put data to the transfer buffer
 156  * by calling "write_modem".
 157  * Otherwise take a new skb out of the queue.
 158  */
 159 static void gigaset_modem_fill(unsigned long data)
 160 {
 161         struct cardstate *cs = (struct cardstate *) data;
 162         struct bc_state *bcs;
 163         struct sk_buff *nextskb;
 164         int sent = 0;
 165
 166         if (!cs) {
 167                 gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
 168                 return;
 169         }
 170         bcs = cs->bcs;
 171         if (!bcs) {
 172                 gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
 173                 return;
 174         }
 175         if (!bcs->tx_skb) {
 176                 /* no skb is being sent; send command if any */
 177                 sent = send_cb(cs);
 178                 gig_dbg(DEBUG_OUTPUT, "%s: send_cb -> %d", __func__, sent);
 179                 if (sent)
 180                         /* something sent or error */
 181                         return;
 182
 183                 /* no command to send; get skb */
 184                 nextskb = skb_dequeue(&bcs->squeue);
 185                 if (!nextskb)
 186                         /* no skb either, nothing to do */
 187                         return;
 188                 bcs->tx_skb = nextskb;
 189
 190                 gig_dbg(DEBUG_INTR, "Dequeued skb (Adr: %lx)",
 191                         (unsigned long) bcs->tx_skb);
 192         }
 193
 194         /* send skb */
 195         gig_dbg(DEBUG_OUTPUT, "%s: tx_skb", __func__);
 196         if (write_modem(cs) < 0)
 197                 gig_dbg(DEBUG_OUTPUT, "%s: write_modem failed", __func__);
 198 }
 199
 200 /*
 201  * throw away all data queued for sending
 202  */
 203 static void flush_send_queue(struct cardstate *cs)
 204 {
 205         struct sk_buff *skb;
 206         struct cmdbuf_t *cb;
 207         unsigned long flags;
 208
 209         /* command queue */
 210         spin_lock_irqsave(&cs->cmdlock, flags);
 211         while ((cb = cs->cmdbuf) != NULL) {
 212                 cs->cmdbuf = cb->next;
 213                 if (cb->wake_tasklet)
 214                         tasklet_schedule(cb->wake_tasklet);
 215                 kfree(cb);
 216         }
 217         cs->cmdbuf = cs->lastcmdbuf = NULL;
 218         cs->cmdbytes = cs->curlen = 0;
 219         spin_unlock_irqrestore(&cs->cmdlock, flags);
 220
 221         /* data queue */
 222         if (cs->bcs->tx_skb)
 223                 dev_kfree_skb_any(cs->bcs->tx_skb);
 224         while ((skb = skb_dequeue(&cs->bcs->squeue)) != NULL)
 225                 dev_kfree_skb_any(skb);
 226 }
 227
 228
 229 /* Gigaset Driver Interface */
 230 /* ======================== */
 231
 232 /*
 233  * queue an AT command string for transmission to the Gigaset device
 234  * parameters:
 235  *      cs              controller state structure
 236  *      buf             buffer containing the string to send
 237  *      len             number of characters to send
 238  *      wake_tasklet    tasklet to run when transmission is complete, or NULL
 239  * return value:
 240  *      number of bytes queued, or error code < 0
 241  */
 242 static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb)
 243 {
 244         unsigned long flags;
 245
 246         gigaset_dbg_buffer(cs->mstate != MS_LOCKED ?
 247                            DEBUG_TRANSCMD : DEBUG_LOCKCMD,
 248                            "CMD Transmit", cb->len, cb->buf);
 249
 250         spin_lock_irqsave(&cs->cmdlock, flags);
 251         cb->prev = cs->lastcmdbuf;
 252         if (cs->lastcmdbuf)
 253                 cs->lastcmdbuf->next = cb;
 254         else {
 255                 cs->cmdbuf = cb;
 256                 cs->curlen = cb->len;
 257         }
 258         cs->cmdbytes += cb->len;
 259         cs->lastcmdbuf = cb;
 260         spin_unlock_irqrestore(&cs->cmdlock, flags);
 261
 262         spin_lock_irqsave(&cs->lock, flags);
 263         if (cs->connected)
 264                 tasklet_schedule(&cs->write_tasklet);
 265         spin_unlock_irqrestore(&cs->lock, flags);
 266         return cb->len;
 267 }
 268
 269 /*
 270  * tty_driver.write_room interface routine
 271  * return number of characters the driver will accept to be written
 272  * parameter:
 273  *      controller state structure
 274  * return value:
 275  *      number of characters
 276  */
 277 static int gigaset_write_room(struct cardstate *cs)
 278 {
 279         unsigned bytes;
 280
 281         bytes = cs->cmdbytes;
 282         return bytes < IF_WRITEBUF ? IF_WRITEBUF - bytes : 0;
 283 }
 284
 285 /*
 286  * tty_driver.chars_in_buffer interface routine
 287  * return number of characters waiting to be sent
 288  * parameter:
 289  *      controller state structure
 290  * return value:
 291  *      number of characters
 292  */
 293 static int gigaset_chars_in_buffer(struct cardstate *cs)
 294 {
 295         return cs->cmdbytes;
 296 }
 297
 298 /*
 299  * implementation of ioctl(GIGASET_BRKCHARS)
 300  * parameter:
 301  *      controller state structure
 302  * return value:
 303  *      -EINVAL (unimplemented function)
 304  */
 305 static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
 306 {
 307         /* not implemented */
 308         return -EINVAL;
 309 }
 310
 311 /*
 312  * Open B channel
 313  * Called by "do_action" in ev-layer.c
 314  */
 315 static int gigaset_init_bchannel(struct bc_state *bcs)
 316 {
 317         /* nothing to do for M10x */
 318         gigaset_bchannel_up(bcs);
 319         return 0;
 320 }
 321
 322 /*
 323  * Close B channel
 324  * Called by "do_action" in ev-layer.c
 325  */
 326 static int gigaset_close_bchannel(struct bc_state *bcs)
 327 {
 328         /* nothing to do for M10x */
 329         gigaset_bchannel_down(bcs);
 330         return 0;
 331 }
 332
 333 /*
 334  * Set up B channel structure
 335  * This is called by "gigaset_initcs" in common.c
 336  */
 337 static int gigaset_initbcshw(struct bc_state *bcs)
 338 {
 339         /* unused */
 340         bcs->hw.ser = NULL;
 341         return 0;
 342 }
 343
 344 /*
 345  * Free B channel structure
 346  * Called by "gigaset_freebcs" in common.c
 347  */
 348 static void gigaset_freebcshw(struct bc_state *bcs)
 349 {
 350         /* unused */
 351 }
 352
 353 /*
 354  * Reinitialize B channel structure
 355  * This is called by "bcs_reinit" in common.c
 356  */
 357 static void gigaset_reinitbcshw(struct bc_state *bcs)
 358 {
 359         /* nothing to do for M10x */
 360 }
 361
 362 /*
 363  * Free hardware specific device data
 364  * This will be called by "gigaset_freecs" in common.c
 365  */
 366 static void gigaset_freecshw(struct cardstate *cs)
 367 {
 368         tasklet_kill(&cs->write_tasklet);
 369         if (!cs->hw.ser)
 370                 return;
 371         dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
 372         platform_device_unregister(&cs->hw.ser->dev);
 373         kfree(cs->hw.ser);
 374         cs->hw.ser = NULL;
 375 }
 376
 377 static void gigaset_device_release(struct device *dev)
 378 {
 379         struct platform_device *pdev = to_platform_device(dev);
 380
 381         /* adapted from platform_device_release() in drivers/base/platform.c */
 382         kfree(dev->platform_data);
 383         kfree(pdev->resource);
 384 }
 385
 386 /*
 387  * Set up hardware specific device data
 388  * This is called by "gigaset_initcs" in common.c
 389  */
 390 static int gigaset_initcshw(struct cardstate *cs)
 391 {
 392         int rc;
 393         struct ser_cardstate *scs;
 394
 395         scs = kzalloc(sizeof(struct ser_cardstate), GFP_KERNEL);
 396         if (!scs) {
 397                 pr_err("out of memory\n");
 398                 return -ENOMEM;
 399         }
 400         cs->hw.ser = scs;
 401
 402         cs->hw.ser->dev.name = GIGASET_MODULENAME;
 403         cs->hw.ser->dev.id = cs->minor_index;
 404         cs->hw.ser->dev.dev.release = gigaset_device_release;
 405         rc = platform_device_register(&cs->hw.ser->dev);
 406         if (rc != 0) {
 407                 pr_err("error %d registering platform device\n", rc);
 408                 kfree(cs->hw.ser);
 409                 cs->hw.ser = NULL;
 410                 return rc;
 411         }
 412         dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
 413
 414         tasklet_init(&cs->write_tasklet,
 415                      gigaset_modem_fill, (unsigned long) cs);
 416         return 0;
 417 }
 418
 419 /*
 420  * set modem control lines
 421  * Parameters:
 422  *      card state structure
 423  *      modem control line state ([TIOCM_DTR]|[TIOCM_RTS])
 424  * Called by "gigaset_start" and "gigaset_enterconfigmode" in common.c
 425  * and by "if_lock" and "if_termios" in interface.c
 426  */
 427 static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
 428                                   unsigned new_state)
 429 {
 430         struct tty_struct *tty = cs->hw.ser->tty;
 431         unsigned int set, clear;
 432
 433         WARN_ON(!tty || !tty->ops);
 434         /* tiocmset is an optional tty driver method */
 435         if (!tty->ops->tiocmset)
 436                 return -EINVAL;
 437         set = new_state & ~old_state;
 438         clear = old_state & ~new_state;
 439         if (!set && !clear)
 440                 return 0;
 441         gig_dbg(DEBUG_IF, "tiocmset set %x clear %x", set, clear);
 442         return tty->ops->tiocmset(tty, set, clear);
 443 }
 444
 445 static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
 446 {
 447         return -EINVAL;
 448 }
 449
 450 static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
 451 {
 452         return -EINVAL;
 453 }
 454
 455 static const struct gigaset_ops ops = {
 456         gigaset_write_cmd,
 457         gigaset_write_room,
 458         gigaset_chars_in_buffer,
 459         gigaset_brkchars,
 460         gigaset_init_bchannel,
 461         gigaset_close_bchannel,
 462         gigaset_initbcshw,
 463         gigaset_freebcshw,
 464         gigaset_reinitbcshw,
 465         gigaset_initcshw,
 466         gigaset_freecshw,
 467         gigaset_set_modem_ctrl,
 468         gigaset_baud_rate,
 469         gigaset_set_line_ctrl,
 470         gigaset_m10x_send_skb,  /* asyncdata.c */
 471         gigaset_m10x_input,     /* asyncdata.c */
 472 };
 473
 474
 475 /* Line Discipline Interface */
 476 /* ========================= */
 477
 478 /* helper functions for cardstate refcounting */
 479 static struct cardstate *cs_get(struct tty_struct *tty)
 480 {
 481         struct cardstate *cs = tty->disc_data;
 482
 483         if (!cs || !cs->hw.ser) {
 484                 gig_dbg(DEBUG_ANY, "%s: no cardstate", __func__);
 485                 return NULL;
 486         }
 487         atomic_inc(&cs->hw.ser->refcnt);
 488         return cs;
 489 }
 490
 491 static void cs_put(struct cardstate *cs)
 492 {
 493         if (atomic_dec_and_test(&cs->hw.ser->refcnt))
 494                 complete(&cs->hw.ser->dead_cmp);
 495 }
 496
 497 /*
 498  * Called by the tty driver when the line discipline is pushed onto the tty.
 499  * Called in process context.
 500  */
 501 static int
 502 gigaset_tty_open(struct tty_struct *tty)
 503 {
 504         struct cardstate *cs;
 505         int rc;
 506
 507         gig_dbg(DEBUG_INIT, "Starting HLL for Gigaset M101");
 508
 509         pr_info(DRIVER_DESC "\n");
 510
 511         if (!driver) {
 512                 pr_err("%s: no driver structure\n", __func__);
 513                 return -ENODEV;
 514         }
 515
 516         /* allocate memory for our device state and initialize it */
 517         cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
 518         if (!cs) {
 519                 rc = -ENODEV;
 520                 goto error;
 521         }
 522
 523         cs->dev = &cs->hw.ser->dev.dev;
 524         cs->hw.ser->tty = tty;
 525         atomic_set(&cs->hw.ser->refcnt, 1);
 526         init_completion(&cs->hw.ser->dead_cmp);
 527         tty->disc_data = cs;
 528
 529         /* Set the amount of data we're willing to receive per call
 530          * from the hardware driver to half of the input buffer size
 531          * to leave some reserve.
 532          * Note: We don't do flow control towards the hardware driver.
 533          * If more data is received than will fit into the input buffer,
 534          * it will be dropped and an error will be logged. This should
 535          * never happen as the device is slow and the buffer size ample.
 536          */
 537         tty->receive_room = RBUFSIZE/2;
 538
 539         /* OK.. Initialization of the datastructures and the HW is done.. Now
 540          * startup system and notify the LL that we are ready to run
 541          */
 542         if (startmode == SM_LOCKED)
 543                 cs->mstate = MS_LOCKED;
 544         rc = gigaset_start(cs);
 545         if (rc < 0) {
 546                 tasklet_kill(&cs->write_tasklet);
 547                 goto error;
 548         }
 549
 550         gig_dbg(DEBUG_INIT, "Startup of HLL done");
 551         return 0;
 552
 553 error:
 554         gig_dbg(DEBUG_INIT, "Startup of HLL failed");
 555         tty->disc_data = NULL;
 556         gigaset_freecs(cs);
 557         return rc;
 558 }
 559
 560 /*
 561  * Called by the tty driver when the line discipline is removed.
 562  * Called from process context.
 563  */
 564 static void
 565 gigaset_tty_close(struct tty_struct *tty)
 566 {
 567         struct cardstate *cs = tty->disc_data;
 568
 569         gig_dbg(DEBUG_INIT, "Stopping HLL for Gigaset M101");
 570
 571         if (!cs) {
 572                 gig_dbg(DEBUG_INIT, "%s: no cardstate", __func__);
 573                 return;
 574         }
 575
 576         /* prevent other callers from entering ldisc methods */
 577         tty->disc_data = NULL;
 578
 579         if (!cs->hw.ser)
 580                 pr_err("%s: no hw cardstate\n", __func__);
 581         else {
 582                 /* wait for running methods to finish */
 583                 if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
 584                         wait_for_completion(&cs->hw.ser->dead_cmp);
 585         }
 586
 587         /* stop operations */
 588         gigaset_stop(cs);
 589         tasklet_kill(&cs->write_tasklet);
 590         flush_send_queue(cs);
 591         cs->dev = NULL;
 592         gigaset_freecs(cs);
 593
 594         gig_dbg(DEBUG_INIT, "Shutdown of HLL done");
 595 }
 596
 597 /*
 598  * Called by the tty driver when the tty line is hung up.
 599  * Wait for I/O to driver to complete and unregister ISDN device.
 600  * This is already done by the close routine, so just call that.
 601  * Called from process context.
 602  */
 603 static int gigaset_tty_hangup(struct tty_struct *tty)
 604 {
 605         gigaset_tty_close(tty);
 606         return 0;
 607 }
 608
 609 /*
 610  * Ioctl on the tty.
 611  * Called in process context only.
 612  * May be re-entered by multiple ioctl calling threads.
 613  */
 614 static int
 615 gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
 616                   unsigned int cmd, unsigned long arg)
 617 {
 618         struct cardstate *cs = cs_get(tty);
 619         int rc, val;
 620         int __user *p = (int __user *)arg;
 621
 622         if (!cs)
 623                 return -ENXIO;
 624
 625         switch (cmd) {
 626
 627         case FIONREAD:
 628                 /* unused, always return zero */
 629                 val = 0;
 630                 rc = put_user(val, p);
 631                 break;
 632
 633         case TCFLSH:
 634                 /* flush our buffers and the serial port's buffer */
 635                 switch (arg) {
 636                 case TCIFLUSH:
 637                         /* no own input buffer to flush */
 638                         break;
 639                 case TCIOFLUSH:
 640                 case TCOFLUSH:
 641                         flush_send_queue(cs);
 642                         break;
 643                 }
 644                 /* Pass through */
 645
 646         default:
 647                 /* pass through to underlying serial device */
 648                 rc = n_tty_ioctl_helper(tty, file, cmd, arg);
 649                 break;
 650         }
 651         cs_put(cs);
 652         return rc;
 653 }
 654
 655 /*
 656  * Called by the tty driver when a block of data has been received.
 657  * Will not be re-entered while running but other ldisc functions
 658  * may be called in parallel.
 659  * Can be called from hard interrupt level as well as soft interrupt
 660  * level or mainline.
 661  * Parameters:
 662  *      tty     tty structure
 663  *      buf     buffer containing received characters
 664  *      cflags  buffer containing error flags for received characters (ignored)
 665  *      count   number of received characters
 666  */
 667 static void
 668 gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,
 669                     char *cflags, int count)
 670 {
 671         struct cardstate *cs = cs_get(tty);
 672         unsigned tail, head, n;
 673         struct inbuf_t *inbuf;
 674
 675         if (!cs)
 676                 return;
 677         inbuf = cs->inbuf;
 678         if (!inbuf) {
 679                 dev_err(cs->dev, "%s: no inbuf\n", __func__);
 680                 cs_put(cs);
 681                 return;
 682         }
 683
 684         tail = inbuf->tail;
 685         head = inbuf->head;
 686         gig_dbg(DEBUG_INTR, "buffer state: %u -> %u, receive %u bytes",
 687                 head, tail, count);
 688
 689         if (head <= tail) {
 690                 /* possible buffer wraparound */
 691                 n = min_t(unsigned, count, RBUFSIZE - tail);
 692                 memcpy(inbuf->data + tail, buf, n);
 693                 tail = (tail + n) % RBUFSIZE;
 694                 buf += n;
 695                 count -= n;
 696         }
 697
 698         if (count > 0) {
 699                 /* tail < head and some data left */
 700                 n = head - tail - 1;
 701                 if (count > n) {
 702                         dev_err(cs->dev,
 703                                 "inbuf overflow, discarding %d bytes\n",
 704                                 count - n);
 705                         count = n;
 706                 }
 707                 memcpy(inbuf->data + tail, buf, count);
 708                 tail += count;
 709         }
 710
 711         gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
 712         inbuf->tail = tail;
 713
 714         /* Everything was received .. Push data into handler */
 715         gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
 716         gigaset_schedule_event(cs);
 717         cs_put(cs);
 718 }
 719
 720 /*
 721  * Called by the tty driver when there's room for more data to send.
 722  */
 723 static void
 724 gigaset_tty_wakeup(struct tty_struct *tty)
 725 {
 726         struct cardstate *cs = cs_get(tty);
 727
 728         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 729         if (!cs)
 730                 return;
 731         tasklet_schedule(&cs->write_tasklet);
 732         cs_put(cs);
 733 }
 734
 735 static struct tty_ldisc_ops gigaset_ldisc = {
 736         .owner          = THIS_MODULE,
 737         .magic          = TTY_LDISC_MAGIC,
 738         .name           = "ser_gigaset",
 739         .open           = gigaset_tty_open,
 740         .close          = gigaset_tty_close,
 741         .hangup         = gigaset_tty_hangup,
 742         .ioctl          = gigaset_tty_ioctl,
 743         .receive_buf    = gigaset_tty_receive,
 744         .write_wakeup   = gigaset_tty_wakeup,
 745 };
 746
 747
 748 /* Initialization / Shutdown */
 749 /* ========================= */
 750
 751 static int __init ser_gigaset_init(void)
 752 {
 753         int rc;
 754
 755         gig_dbg(DEBUG_INIT, "%s", __func__);
 756         rc = platform_driver_register(&device_driver);
 757         if (rc != 0) {
 758                 pr_err("error %d registering platform driver\n", rc);
 759                 return rc;
 760         }
 761
 762         /* allocate memory for our driver state and initialize it */
 763         driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
 764                                     GIGASET_MODULENAME, GIGASET_DEVNAME,
 765                                     &ops, THIS_MODULE);
 766         if (!driver)
 767                 goto error;
 768
 769         rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
 770         if (rc != 0) {
 771                 pr_err("error %d registering line discipline\n", rc);
 772                 goto error;
 773         }
 774
 775         return 0;
 776
 777 error:
 778         if (driver) {
 779                 gigaset_freedriver(driver);
 780                 driver = NULL;
 781         }
 782         platform_driver_unregister(&device_driver);
 783         return rc;
 784 }
 785
 786 static void __exit ser_gigaset_exit(void)
 787 {
 788         int rc;
 789
 790         gig_dbg(DEBUG_INIT, "%s", __func__);
 791
 792         if (driver) {
 793                 gigaset_freedriver(driver);
 794                 driver = NULL;
 795         }
 796
 797         rc = tty_unregister_ldisc(N_GIGASET_M101);
 798         if (rc != 0)
 799                 pr_err("error %d unregistering line discipline\n", rc);
 800
 801         platform_driver_unregister(&device_driver);
 802 }
 803
 804 module_init(ser_gigaset_init);
 805 module_exit(ser_gigaset_exit);