drivers/char/n_r3964.c

   1 /* r3964 linediscipline for linux
   2  *
   3  * -----------------------------------------------------------
   4  * Copyright by
   5  * Philips Automation Projects
   6  * Kassel (Germany)
   7  * http://www.pap-philips.de
   8  * -----------------------------------------------------------
   9  * This software may be used and distributed according to the terms of
  10  * the GNU General Public License, incorporated herein by reference.
  11  *
  12  * Author:
  13  * L. Haag
  14  *
  15  * $Log: n_r3964.c,v $
  16  * Revision 1.1.1.1  2005/04/11 02:50:17  jack
  17  * first release
  18  *
  19  * Revision 1.1.1.1  2005/01/10 13:16:18  jack
  20  * First release
  21  *
  22  * Revision 1.8  2000/03/23 14:14:54  dwmw2
  23  * Fix race in sleeping in r3964_read()
  24  *
  25  * Revision 1.7  1999/28/08 11:41:50  dwmw2
  26  * Port to 2.3 kernel
  27  *
  28  * Revision 1.6  1998/09/30 00:40:40  dwmw2
  29  * Fixed compilation on 2.0.x kernels
  30  * Updated to newly registered tty-ldisc number 9
  31  *
  32  * Revision 1.5  1998/09/04 21:57:36  dwmw2
  33  * Signal handling bug fixes, port to 2.1.x.
  34  *
  35  * Revision 1.4  1998/04/02 20:26:59  lhaag
  36  * select, blocking, ...
  37  *
  38  * Revision 1.3  1998/02/12 18:58:43  root
  39  * fixed some memory leaks
  40  * calculation of checksum characters
  41  *
  42  * Revision 1.2  1998/02/07 13:03:34  root
  43  * ioctl read_telegram
  44  *
  45  * Revision 1.1  1998/02/06 19:21:03  root
  46  * Initial revision
  47  *
  48  *
  49  */
  50
  51 #include <linux/module.h>
  52 #include <linux/kernel.h>
  53 #include <linux/sched.h>
  54 #include <linux/types.h>
  55 #include <linux/fcntl.h>
  56 #include <linux/interrupt.h>
  57 #include <linux/ptrace.h>
  58 #include <linux/ioport.h>
  59 #include <linux/in.h>
  60 #include <linux/slab.h>
  61 #include <linux/tty.h>
  62 #include <linux/errno.h>
  63 #include <linux/string.h>   /* used in new tty drivers */
  64 #include <linux/signal.h>   /* used in new tty drivers */
  65 #include <linux/ioctl.h>
  66 #include <linux/n_r3964.h>
  67 #include <linux/poll.h>
  68 #include <linux/init.h>
  69 #include <asm/uaccess.h>
  70
  71
  72 //#define DEBUG_QUEUE
  73
  74 /* Log successful handshake and protocol operations  */
  75 //#define DEBUG_PROTO_S
  76
  77 /* Log handshake and protocol errors: */
  78 //#define DEBUG_PROTO_E
  79
  80 /* Log Linediscipline operations (open, close, read, write...): */
  81 //#define DEBUG_LDISC
  82
  83 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
  84 //#define DEBUG_MODUL
  85
  86 /* Macro helpers for debug output: */
  87 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args);
  88
  89 #ifdef DEBUG_MODUL
  90 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args);
  91 #else
  92 #define TRACE_M(fmt, arg...) /**/
  93 #endif
  94
  95 #ifdef DEBUG_PROTO_S
  96 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args);
  97 #else
  98 #define TRACE_PS(fmt, arg...) /**/
  99 #endif
 100
 101 #ifdef DEBUG_PROTO_E
 102 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args);
 103 #else
 104 #define TRACE_PE(fmt, arg...) /**/
 105 #endif
 106
 107 #ifdef DEBUG_LDISC
 108 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args);
 109 #else
 110 #define TRACE_L(fmt, arg...) /**/
 111 #endif
 112
 113 #ifdef DEBUG_QUEUE
 114 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args);
 115 #else
 116 #define TRACE_Q(fmt, arg...) /**/
 117 #endif
 118
 119 static void on_timer_1(void*);
 120 static void on_timer_2(void*);
 121 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
 122 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
 123 static void put_char(struct r3964_info *pInfo, unsigned char ch);
 124 static void trigger_transmit(struct r3964_info *pInfo);
 125 static void retry_transmit(struct r3964_info *pInfo);
 126 static void transmit_block(struct r3964_info *pInfo);
 127 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
 128 static void receive_error(struct r3964_info *pInfo, const char flag);
 129 static void on_timeout(struct r3964_info *pInfo);
 130 static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg);
 131 static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char *buf);
 132 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 133              int error_code, struct r3964_block_header *pBlock);
 134 static struct r3964_message* remove_msg(struct r3964_info *pInfo,
 135              struct r3964_client_info *pClient);
 136 static void remove_client_block(struct r3964_info *pInfo,
 137                 struct r3964_client_info *pClient);
 138
 139 static int  r3964_open(struct tty_struct *tty);
 140 static void r3964_close(struct tty_struct *tty);
 141 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
 142                      unsigned char *buf, size_t nr);
 143 static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
 144                       const unsigned char * buf, size_t nr);
 145 static int r3964_ioctl(struct tty_struct * tty, struct file * file,
 146                        unsigned int cmd, unsigned long arg);
 147 static void r3964_set_termios(struct tty_struct *tty, struct termios * old);
 148 static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
 149                       struct poll_table_struct  *wait);
 150 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 151                               char *fp, int count);
 152 static int  r3964_receive_room(struct tty_struct *tty);
 153
 154 static struct tty_ldisc tty_ldisc_N_R3964 = {
 155         TTY_LDISC_MAGIC,       /* magic */
 156         "R3964",               /* name */
 157         0,                     /* num */
 158         0,                     /* flags */
 159         r3964_open,            /* open */
 160         r3964_close,           /* close */
 161         0,                     /* flush_buffer */
 162         0,                     /* chars_in_buffer */
 163         r3964_read,            /* read */
 164         r3964_write,           /* write */
 165         r3964_ioctl,           /* ioctl */
 166         r3964_set_termios,     /* set_termios */
 167         r3964_poll,            /* poll */
 168         r3964_receive_buf,     /* receive_buf */
 169         r3964_receive_room,    /* receive_room */
 170         0                      /* write_wakeup */
 171 };
 172
 173
 174
 175 static void dump_block(const unsigned char *block, unsigned int length)
 176 {
 177    unsigned int i,j;
 178    char linebuf[16*3+1];
 179
 180    for(i=0;i<length;i+=16)
 181    {
 182       for(j=0;(j<16) && (j+i<length);j++)
 183       {
 184          sprintf(linebuf+3*j,"%02x ",block[i+j]);
 185       }
 186       linebuf[3*j]='\0';
 187       TRACE_PS("%s",linebuf);
 188    }
 189 }
 190
 191
 192
 193
 194 /*************************************************************
 195  * Driver initialisation
 196  *************************************************************/
 197
 198
 199 /*************************************************************
 200  * Module support routines
 201  *************************************************************/
 202
 203 static void __exit r3964_exit(void)
 204 {
 205    int status;
 206
 207    TRACE_M ("cleanup_module()");
 208
 209    status=tty_register_ldisc(N_R3964, NULL);
 210
 211    if(status!=0)
 212    {
 213       printk(KERN_ERR "r3964: error unregistering linediscipline: %d\n", status);
 214    }
 215    else
 216    {
 217       TRACE_L("linediscipline successfully unregistered");
 218    }
 219
 220 }
 221
 222 static int __init r3964_init(void)
 223 {
 224    int status;
 225
 226    printk ("r3964: Philips r3964 Driver $Revision: 1.1.1.1 $\n");
 227
 228    /*
 229     * Register the tty line discipline
 230     */
 231
 232    status = tty_register_ldisc (N_R3964, &tty_ldisc_N_R3964);
 233    if (status == 0)
 234      {
 235        TRACE_L("line discipline %d registered", N_R3964);
 236        TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 237                tty_ldisc_N_R3964.num);
 238        TRACE_L("open=%x", (int)tty_ldisc_N_R3964.open);
 239        TRACE_L("tty_ldisc_N_R3964 = %x", (int)&tty_ldisc_N_R3964);
 240      }
 241    else
 242      {
 243        printk (KERN_ERR "r3964: error registering line discipline: %d\n", status);
 244      }
 245    return status;
 246 }
 247
 248 module_init(r3964_init);
 249 module_exit(r3964_exit);
 250
 251
 252 /*************************************************************
 253  * Protocol implementation routines
 254  *************************************************************/
 255
 256 static void on_timer_1(void *arg)
 257 {
 258    struct r3964_info *pInfo = (struct r3964_info *)arg;
 259
 260    if(pInfo->count_down)
 261    {
 262       if(!--pInfo->count_down)
 263       {
 264          on_timeout(pInfo);
 265       }
 266    }
 267    queue_task(&pInfo->bh_2, &tq_timer);
 268 }
 269
 270 static void on_timer_2(void *arg)
 271 {
 272    struct r3964_info *pInfo = (struct r3964_info *)arg;
 273
 274    if(pInfo->count_down)
 275    {
 276       if(!--pInfo->count_down)
 277       {
 278          on_timeout(pInfo);
 279       }
 280    }
 281    queue_task(&pInfo->bh_1, &tq_timer);
 282 }
 283
 284 static void add_tx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
 285 {
 286    unsigned long flags;
 287
 288    save_flags(flags);
 289    cli();
 290
 291    pHeader->next = NULL;
 292
 293    if(pInfo->tx_last == NULL)
 294    {
 295       pInfo->tx_first = pInfo->tx_last = pHeader;
 296    }
 297    else
 298    {
 299       pInfo->tx_last->next = pHeader;
 300       pInfo->tx_last = pHeader;
 301    }
 302
 303    restore_flags(flags);
 304
 305    TRACE_Q("add_tx_queue %x, length %d, tx_first = %x",
 306           (int)pHeader, pHeader->length, (int)pInfo->tx_first );
 307 }
 308
 309 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 310 {
 311    struct r3964_block_header *pHeader;
 312    unsigned long flags;
 313 #ifdef DEBUG_QUEUE
 314    struct r3964_block_header *pDump;
 315 #endif
 316
 317    pHeader = pInfo->tx_first;
 318
 319    if(pHeader==NULL)
 320       return;
 321
 322 #ifdef DEBUG_QUEUE
 323    printk("r3964: remove_from_tx_queue: %x, length %d - ",
 324           (int)pHeader, (int)pHeader->length );
 325    for(pDump=pHeader;pDump;pDump=pDump->next)
 326          printk("%x ", (int)pDump);
 327    printk("\n");
 328 #endif
 329
 330
 331    if(pHeader->owner)
 332    {
 333       if(error_code)
 334       {
 335           add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 336                   error_code, NULL);
 337       }
 338       else
 339       {
 340           add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 341                   error_code, NULL);
 342       }
 343       wake_up_interruptible (&pInfo->read_wait);
 344    }
 345
 346    save_flags(flags);
 347    cli();
 348
 349    pInfo->tx_first = pHeader->next;
 350    if(pInfo->tx_first==NULL)
 351    {
 352       pInfo->tx_last = NULL;
 353    }
 354
 355    restore_flags(flags);
 356
 357    kfree(pHeader);
 358    TRACE_M("remove_from_tx_queue - kfree %x",(int)pHeader);
 359
 360    TRACE_Q("remove_from_tx_queue: tx_first = %x, tx_last = %x",
 361           (int)pInfo->tx_first, (int)pInfo->tx_last );
 362 }
 363
 364 static void add_rx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
 365 {
 366    unsigned long flags;
 367
 368    save_flags(flags);
 369    cli();
 370
 371    pHeader->next = NULL;
 372
 373    if(pInfo->rx_last == NULL)
 374    {
 375       pInfo->rx_first = pInfo->rx_last = pHeader;
 376    }
 377    else
 378    {
 379       pInfo->rx_last->next = pHeader;
 380       pInfo->rx_last = pHeader;
 381    }
 382    pInfo->blocks_in_rx_queue++;
 383
 384    restore_flags(flags);
 385
 386    TRACE_Q("add_rx_queue: %x, length = %d, rx_first = %x, count = %d",
 387           (int)pHeader, pHeader->length,
 388           (int)pInfo->rx_first, pInfo->blocks_in_rx_queue);
 389 }
 390
 391 static void remove_from_rx_queue(struct r3964_info *pInfo,
 392                  struct r3964_block_header *pHeader)
 393 {
 394    unsigned long flags;
 395    struct r3964_block_header *pFind;
 396
 397    if(pHeader==NULL)
 398       return;
 399
 400    TRACE_Q("remove_from_rx_queue: rx_first = %x, rx_last = %x, count = %d",
 401           (int)pInfo->rx_first, (int)pInfo->rx_last, pInfo->blocks_in_rx_queue );
 402    TRACE_Q("remove_from_rx_queue: %x, length %d",
 403           (int)pHeader, (int)pHeader->length );
 404
 405    save_flags(flags);
 406    cli();
 407
 408    if(pInfo->rx_first == pHeader)
 409    {
 410       /* Remove the first block in the linked list: */
 411       pInfo->rx_first = pHeader->next;
 412
 413       if(pInfo->rx_first==NULL)
 414       {
 415          pInfo->rx_last = NULL;
 416       }
 417       pInfo->blocks_in_rx_queue--;
 418    }
 419    else
 420    {
 421       /* Find block to remove: */
 422       for(pFind=pInfo->rx_first; pFind; pFind=pFind->next)
 423       {
 424          if(pFind->next == pHeader)
 425          {
 426             /* Got it. */
 427             pFind->next = pHeader->next;
 428             pInfo->blocks_in_rx_queue--;
 429             if(pFind->next==NULL)
 430             {
 431                /* Oh, removed the last one! */
 432                pInfo->rx_last = pFind;
 433             }
 434             break;
 435          }
 436       }
 437    }
 438
 439    restore_flags(flags);
 440
 441    kfree(pHeader);
 442    TRACE_M("remove_from_rx_queue - kfree %x",(int)pHeader);
 443
 444    TRACE_Q("remove_from_rx_queue: rx_first = %x, rx_last = %x, count = %d",
 445           (int)pInfo->rx_first, (int)pInfo->rx_last, pInfo->blocks_in_rx_queue );
 446 }
 447
 448 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 449 {
 450    struct tty_struct *tty = pInfo->tty;
 451
 452    if(tty==NULL)
 453       return;
 454
 455    if(tty->driver.put_char)
 456    {
 457       tty->driver.put_char(tty, ch);
 458    }
 459    pInfo->bcc ^= ch;
 460 }
 461
 462 static void flush(struct r3964_info *pInfo)
 463 {
 464    struct tty_struct *tty = pInfo->tty;
 465
 466    if(tty==NULL)
 467       return;
 468
 469    if(tty->driver.flush_chars)
 470    {
 471       tty->driver.flush_chars(tty);
 472    }
 473 }
 474
 475 static void trigger_transmit(struct r3964_info *pInfo)
 476 {
 477    unsigned long flags;
 478
 479
 480    save_flags(flags);
 481    cli();
 482
 483    if((pInfo->state == R3964_IDLE) && (pInfo->tx_first!=NULL))
 484    {
 485       pInfo->state = R3964_TX_REQUEST;
 486       pInfo->count_down = R3964_TO_QVZ;
 487       pInfo->nRetry=0;
 488       pInfo->flags &= ~R3964_ERROR;
 489
 490       restore_flags(flags);
 491
 492       TRACE_PS("trigger_transmit - sent STX");
 493
 494       put_char(pInfo, STX);
 495       flush(pInfo);
 496
 497       pInfo->bcc = 0;
 498    }
 499    else
 500    {
 501       restore_flags(flags);
 502    }
 503 }
 504
 505 static void retry_transmit(struct r3964_info *pInfo)
 506 {
 507    if(pInfo->nRetry<R3964_MAX_RETRIES)
 508    {
 509       TRACE_PE("transmission failed. Retry #%d",
 510              pInfo->nRetry);
 511       pInfo->bcc = 0;
 512       put_char(pInfo, STX);
 513       flush(pInfo);
 514       pInfo->state = R3964_TX_REQUEST;
 515       pInfo->count_down = R3964_TO_QVZ;
 516       pInfo->nRetry++;
 517    }
 518    else
 519    {
 520       TRACE_PE("transmission failed after %d retries",
 521              R3964_MAX_RETRIES);
 522
 523       remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 524
 525       put_char(pInfo, NAK);
 526       flush(pInfo);
 527       pInfo->state = R3964_IDLE;
 528
 529       trigger_transmit(pInfo);
 530    }
 531 }
 532
 533
 534 static void transmit_block(struct r3964_info *pInfo)
 535 {
 536    struct tty_struct *tty = pInfo->tty;
 537    struct r3964_block_header *pBlock = pInfo->tx_first;
 538    int room=0;
 539
 540    if((tty==NULL) || (pBlock==NULL))
 541    {
 542       return;
 543    }
 544
 545    if(tty->driver.write_room)
 546       room=tty->driver.write_room(tty);
 547
 548    TRACE_PS("transmit_block %x, room %d, length %d",
 549           (int)pBlock, room, pBlock->length);
 550
 551    while(pInfo->tx_position < pBlock->length)
 552    {
 553       if(room<2)
 554          break;
 555
 556       if(pBlock->data[pInfo->tx_position]==DLE)
 557       {
 558          /* send additional DLE char: */
 559          put_char(pInfo, DLE);
 560       }
 561       put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 562
 563       room--;
 564    }
 565
 566    if((pInfo->tx_position == pBlock->length) && (room>=3))
 567    {
 568       put_char(pInfo, DLE);
 569       put_char(pInfo, ETX);
 570       if(pInfo->flags & R3964_BCC)
 571       {
 572          put_char(pInfo, pInfo->bcc);
 573       }
 574       pInfo->state = R3964_WAIT_FOR_TX_ACK;
 575       pInfo->count_down = R3964_TO_QVZ;
 576    }
 577    flush(pInfo);
 578 }
 579
 580 static void on_receive_block(struct r3964_info *pInfo)
 581 {
 582    unsigned int length;
 583    struct r3964_client_info *pClient;
 584    struct r3964_block_header *pBlock;
 585
 586    length=pInfo->rx_position;
 587
 588    /* compare byte checksum characters: */
 589    if(pInfo->flags & R3964_BCC)
 590    {
 591       if(pInfo->bcc!=pInfo->last_rx)
 592       {
 593          TRACE_PE("checksum error - got %x but expected %x",
 594                 pInfo->last_rx, pInfo->bcc);
 595          pInfo->flags |= R3964_CHECKSUM;
 596       }
 597    }
 598
 599    /* check for errors (parity, overrun,...): */
 600    if(pInfo->flags & R3964_ERROR)
 601    {
 602       TRACE_PE("on_receive_block - transmission failed error %x",
 603              pInfo->flags & R3964_ERROR);
 604
 605       put_char(pInfo, NAK);
 606       flush(pInfo);
 607       if(pInfo->nRetry<R3964_MAX_RETRIES)
 608       {
 609          pInfo->state=R3964_WAIT_FOR_RX_REPEAT;
 610          pInfo->count_down = R3964_TO_RX_PANIC;
 611          pInfo->nRetry++;
 612       }
 613       else
 614       {
 615          TRACE_PE("on_receive_block - failed after max retries");
 616          pInfo->state=R3964_IDLE;
 617       }
 618       return;
 619    }
 620
 621
 622    /* received block; submit DLE: */
 623    put_char(pInfo, DLE);
 624    flush(pInfo);
 625    pInfo->count_down=0;
 626    TRACE_PS(" rx success: got %d chars", length);
 627
 628    /* prepare struct r3964_block_header: */
 629    pBlock = kmalloc(length+sizeof(struct r3964_block_header), GFP_KERNEL);
 630    TRACE_M("on_receive_block - kmalloc %x",(int)pBlock);
 631
 632    if(pBlock==NULL)
 633       return;
 634
 635    pBlock->length = length;
 636    pBlock->data   = ((unsigned char*)pBlock)+sizeof(struct r3964_block_header);
 637    pBlock->locks  = 0;
 638    pBlock->next   = NULL;
 639    pBlock->owner  = NULL;
 640
 641    memcpy(pBlock->data, pInfo->rx_buf, length);
 642
 643    /* queue block into rx_queue: */
 644    add_rx_queue(pInfo, pBlock);
 645
 646    /* notify attached client processes: */
 647    for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
 648    {
 649       if(pClient->sig_flags & R3964_SIG_DATA)
 650       {
 651          add_msg(pClient, R3964_MSG_DATA, length, R3964_OK, pBlock);
 652       }
 653    }
 654    wake_up_interruptible (&pInfo->read_wait);
 655
 656    pInfo->state = R3964_IDLE;
 657
 658    trigger_transmit(pInfo);
 659 }
 660
 661
 662 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 663 {
 664    switch(pInfo->state)
 665    {
 666       case R3964_TX_REQUEST:
 667          if(c==DLE)
 668          {
 669             TRACE_PS("TX_REQUEST - got DLE");
 670
 671             pInfo->state = R3964_TRANSMITTING;
 672             pInfo->tx_position = 0;
 673
 674             transmit_block(pInfo);
 675          }
 676          else if(c==STX)
 677          {
 678             if(pInfo->nRetry==0)
 679             {
 680                TRACE_PE("TX_REQUEST - init conflict");
 681                if(pInfo->priority == R3964_SLAVE)
 682                {
 683                   goto start_receiving;
 684                }
 685             }
 686             else
 687             {
 688                TRACE_PE("TX_REQUEST - secondary init conflict!?"
 689                         " Switching to SLAVE mode for next rx.");
 690                goto start_receiving;
 691             }
 692          }
 693          else
 694          {
 695             TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 696             retry_transmit(pInfo);
 697          }
 698          break;
 699       case R3964_TRANSMITTING:
 700          if(c==NAK)
 701          {
 702             TRACE_PE("TRANSMITTING - got NAK");
 703             retry_transmit(pInfo);
 704          }
 705          else
 706          {
 707             TRACE_PE("TRANSMITTING - got illegal char");
 708
 709             pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 710             pInfo->count_down = R3964_TO_ZVZ;
 711          }
 712          break;
 713       case R3964_WAIT_FOR_TX_ACK:
 714          if(c==DLE)
 715          {
 716             TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 717             remove_from_tx_queue(pInfo, R3964_OK);
 718
 719             pInfo->state = R3964_IDLE;
 720             trigger_transmit(pInfo);
 721          }
 722          else
 723          {
 724             retry_transmit(pInfo);
 725          }
 726          break;
 727       case R3964_WAIT_FOR_RX_REPEAT:
 728          /* FALLTROUGH */
 729       case R3964_IDLE:
 730          if(c==STX)
 731          {
 732             /* Prevent rx_queue from overflow: */
 733             if(pInfo->blocks_in_rx_queue >= R3964_MAX_BLOCKS_IN_RX_QUEUE)
 734             {
 735                TRACE_PE("IDLE - got STX but no space in rx_queue!");
 736                pInfo->state=R3964_WAIT_FOR_RX_BUF;
 737                pInfo->count_down = R3964_TO_NO_BUF;
 738                break;
 739             }
 740 start_receiving:
 741             /* Ok, start receiving: */
 742             TRACE_PS("IDLE - got STX");
 743             pInfo->rx_position = 0;
 744             pInfo->last_rx = 0;
 745             pInfo->flags &= ~R3964_ERROR;
 746             pInfo->state=R3964_RECEIVING;
 747             pInfo->count_down = R3964_TO_ZVZ;
 748             pInfo->nRetry = 0;
 749             put_char(pInfo, DLE);
 750             flush(pInfo);
 751             pInfo->bcc = 0;
 752          }
 753          break;
 754       case R3964_RECEIVING:
 755          if(pInfo->rx_position < RX_BUF_SIZE)
 756          {
 757             pInfo->bcc ^= c;
 758
 759             if(c==DLE)
 760             {
 761                if(pInfo->last_rx==DLE)
 762                {
 763                   pInfo->last_rx = 0;
 764                   goto char_to_buf;
 765                }
 766                pInfo->last_rx = DLE;
 767                break;
 768             }
 769             else if((c==ETX) && (pInfo->last_rx==DLE))
 770             {
 771                if(pInfo->flags & R3964_BCC)
 772                {
 773                   pInfo->state = R3964_WAIT_FOR_BCC;
 774                   pInfo->count_down = R3964_TO_ZVZ;
 775                }
 776                else
 777                {
 778                   on_receive_block(pInfo);
 779                }
 780             }
 781             else
 782             {
 783                pInfo->last_rx = c;
 784 char_to_buf:
 785                pInfo->rx_buf[pInfo->rx_position++] = c;
 786                pInfo->count_down = R3964_TO_ZVZ;
 787             }
 788          }
 789         /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 790          break;
 791       case R3964_WAIT_FOR_BCC:
 792          pInfo->last_rx = c;
 793          on_receive_block(pInfo);
 794          break;
 795    }
 796 }
 797
 798 static void receive_error(struct r3964_info *pInfo, const char flag)
 799 {
 800     switch (flag)
 801     {
 802     case TTY_NORMAL:
 803         break;
 804     case TTY_BREAK:
 805         TRACE_PE("received break")
 806         pInfo->flags |= R3964_BREAK;
 807         break;
 808     case TTY_PARITY:
 809         TRACE_PE("parity error")
 810         pInfo->flags |= R3964_PARITY;
 811         break;
 812     case TTY_FRAME:
 813         TRACE_PE("frame error")
 814         pInfo->flags |= R3964_FRAME;
 815         break;
 816     case TTY_OVERRUN:
 817         TRACE_PE("frame overrun")
 818         pInfo->flags |= R3964_OVERRUN;
 819         break;
 820     default:
 821         TRACE_PE("receive_error - unknown flag %d", flag);
 822         pInfo->flags |= R3964_UNKNOWN;
 823         break;
 824     }
 825 }
 826
 827 static void on_timeout(struct r3964_info *pInfo)
 828 {
 829    switch(pInfo->state)
 830    {
 831       case R3964_TX_REQUEST:
 832          TRACE_PE("TX_REQUEST - timeout");
 833          retry_transmit(pInfo);
 834          break;
 835       case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 836          put_char(pInfo, NAK);
 837          flush(pInfo);
 838          retry_transmit(pInfo);
 839          break;
 840       case R3964_WAIT_FOR_TX_ACK:
 841          TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 842          retry_transmit(pInfo);
 843          break;
 844       case R3964_WAIT_FOR_RX_BUF:
 845          TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 846          put_char(pInfo, NAK);
 847          flush(pInfo);
 848          pInfo->state=R3964_IDLE;
 849          break;
 850       case R3964_RECEIVING:
 851          TRACE_PE("RECEIVING - timeout after %d chars",
 852                   pInfo->rx_position);
 853          put_char(pInfo, NAK);
 854          flush(pInfo);
 855          pInfo->state=R3964_IDLE;
 856          break;
 857       case R3964_WAIT_FOR_RX_REPEAT:
 858          TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 859          pInfo->state=R3964_IDLE;
 860          break;
 861       case R3964_WAIT_FOR_BCC:
 862          TRACE_PE("WAIT_FOR_BCC - timeout");
 863          put_char(pInfo, NAK);
 864          flush(pInfo);
 865          pInfo->state=R3964_IDLE;
 866          break;
 867    }
 868 }
 869
 870 static struct r3964_client_info *findClient(
 871   struct r3964_info *pInfo, pid_t pid)
 872 {
 873    struct r3964_client_info *pClient;
 874
 875    for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
 876    {
 877       if(pClient->pid == pid)
 878       {
 879          return pClient;
 880       }
 881    }
 882    return NULL;
 883 }
 884
 885 static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg)
 886 {
 887    struct r3964_client_info *pClient;
 888    struct r3964_client_info **ppClient;
 889    struct r3964_message *pMsg;
 890
 891    if((arg & R3964_SIG_ALL)==0)
 892    {
 893       /* Remove client from client list */
 894       for(ppClient=&pInfo->firstClient; *ppClient; ppClient=&(*ppClient)->next)
 895       {
 896          pClient = *ppClient;
 897
 898          if(pClient->pid == pid)
 899          {
 900             TRACE_PS("removing client %d from client list", pid);
 901             *ppClient = pClient->next;
 902             while(pClient->msg_count)
 903             {
 904                pMsg=remove_msg(pInfo, pClient);
 905                if(pMsg)
 906                {
 907                   kfree(pMsg);
 908                   TRACE_M("enable_signals - msg kfree %x",(int)pMsg);
 909                }
 910             }
 911             kfree(pClient);
 912             TRACE_M("enable_signals - kfree %x",(int)pClient);
 913             return 0;
 914          }
 915       }
 916       return -EINVAL;
 917    }
 918    else
 919    {
 920       pClient=findClient(pInfo, pid);
 921       if(pClient)
 922       {
 923          /* update signal options */
 924          pClient->sig_flags=arg;
 925       }
 926       else
 927       {
 928          /* add client to client list */
 929          pClient=kmalloc(sizeof(struct r3964_client_info), GFP_KERNEL);
 930          TRACE_M("enable_signals - kmalloc %x",(int)pClient);
 931          if(pClient==NULL)
 932             return -ENOMEM;
 933
 934          TRACE_PS("add client %d to client list", pid);
 935          pClient->sig_flags=arg;
 936          pClient->pid = pid;
 937          pClient->next=pInfo->firstClient;
 938          pClient->first_msg = NULL;
 939          pClient->last_msg = NULL;
 940          pClient->next_block_to_read = NULL;
 941          pClient->msg_count = 0;
 942          pInfo->firstClient=pClient;
 943       }
 944    }
 945
 946    return 0;
 947 }
 948
 949 static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char *buf)
 950 {
 951     struct r3964_client_info *pClient;
 952     struct r3964_block_header *block;
 953
 954     if(!buf)
 955     {
 956         return -EINVAL;
 957     }
 958
 959     pClient=findClient(pInfo,pid);
 960     if(pClient==NULL)
 961     {
 962        return -EINVAL;
 963     }
 964
 965     block=pClient->next_block_to_read;
 966     if(!block)
 967     {
 968        return 0;
 969     }
 970     else
 971     {
 972       if (copy_to_user (buf, block->data, block->length))
 973         return -EFAULT;
 974
 975        remove_client_block(pInfo, pClient);
 976        return block->length;
 977     }
 978
 979     return -EINVAL;
 980 }
 981
 982 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 983              int error_code, struct r3964_block_header *pBlock)
 984 {
 985    struct r3964_message *pMsg;
 986    unsigned long flags;
 987
 988    if(pClient->msg_count<R3964_MAX_MSG_COUNT-1)
 989    {
 990 queue_the_message:
 991
 992       pMsg = kmalloc(sizeof(struct r3964_message), GFP_KERNEL);
 993       TRACE_M("add_msg - kmalloc %x",(int)pMsg);
 994       if(pMsg==NULL) {
 995          return;
 996       }
 997
 998       save_flags(flags);
 999       cli();
1000
1001       pMsg->msg_id = msg_id;
1002       pMsg->arg    = arg;
1003       pMsg->error_code = error_code;
1004       pMsg->block  = pBlock;
1005       pMsg->next   = NULL;
1006
1007       if(pClient->last_msg==NULL)
1008       {
1009          pClient->first_msg=pClient->last_msg=pMsg;
1010       }
1011       else
1012       {
1013          pClient->last_msg->next = pMsg;
1014          pClient->last_msg=pMsg;
1015       }
1016
1017       pClient->msg_count++;
1018
1019       if(pBlock!=NULL)
1020       {
1021          pBlock->locks++;
1022       }
1023       restore_flags(flags);
1024    }
1025    else
1026    {
1027       if((pClient->last_msg->msg_id == R3964_MSG_ACK)
1028                  && (pClient->last_msg->error_code==R3964_OVERFLOW))
1029       {
1030          pClient->last_msg->arg++;
1031                  TRACE_PE("add_msg - inc prev OVERFLOW-msg");
1032       }
1033       else
1034       {
1035          msg_id = R3964_MSG_ACK;
1036          arg = 0;
1037                  error_code = R3964_OVERFLOW;
1038          pBlock = NULL;
1039                  TRACE_PE("add_msg - queue OVERFLOW-msg");
1040          goto queue_the_message;
1041       }
1042    }
1043    /* Send SIGIO signal to client process: */
1044    if(pClient->sig_flags & R3964_USE_SIGIO)
1045    {
1046       kill_proc(pClient->pid, SIGIO, 1);
1047    }
1048 }
1049
1050 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
1051                        struct r3964_client_info *pClient)
1052 {
1053    struct r3964_message *pMsg=NULL;
1054    unsigned long flags;
1055
1056    if(pClient->first_msg)
1057    {
1058       save_flags(flags);
1059       cli();
1060
1061       pMsg = pClient->first_msg;
1062       pClient->first_msg = pMsg->next;
1063       if(pClient->first_msg==NULL)
1064       {
1065          pClient->last_msg = NULL;
1066       }
1067
1068       pClient->msg_count--;
1069       if(pMsg->block)
1070       {
1071         remove_client_block(pInfo, pClient);
1072         pClient->next_block_to_read = pMsg->block;
1073       }
1074       restore_flags(flags);
1075    }
1076    return pMsg;
1077 }
1078
1079 static void remove_client_block(struct r3964_info *pInfo,
1080                 struct r3964_client_info *pClient)
1081 {
1082     struct r3964_block_header *block;
1083
1084     TRACE_PS("remove_client_block PID %d", pClient->pid);
1085
1086     block=pClient->next_block_to_read;
1087     if(block)
1088     {
1089         block->locks--;
1090         if(block->locks==0)
1091         {
1092             remove_from_rx_queue(pInfo, block);
1093         }
1094     }
1095     pClient->next_block_to_read = NULL;
1096 }
1097
1098
1099 /*************************************************************
1100  * Line discipline routines
1101  *************************************************************/
1102
1103 static int r3964_open(struct tty_struct *tty)
1104 {
1105    struct r3964_info *pInfo;
1106
1107    MOD_INC_USE_COUNT;
1108
1109    TRACE_L("open");
1110    TRACE_L("tty=%x, PID=%d, disc_data=%x",
1111           (int)tty, current->pid, (int)tty->disc_data);
1112
1113    pInfo=kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
1114    TRACE_M("r3964_open - info kmalloc %x",(int)pInfo);
1115
1116    if(!pInfo)
1117    {
1118       printk(KERN_ERR "r3964: failed to alloc info structure\n");
1119       return -ENOMEM;
1120    }
1121
1122    pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
1123    TRACE_M("r3964_open - rx_buf kmalloc %x",(int)pInfo->rx_buf);
1124
1125    if(!pInfo->rx_buf)
1126    {
1127       printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
1128       kfree(pInfo);
1129       TRACE_M("r3964_open - info kfree %x",(int)pInfo);
1130       return -ENOMEM;
1131    }
1132
1133    pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
1134    TRACE_M("r3964_open - tx_buf kmalloc %x",(int)pInfo->tx_buf);
1135
1136    if(!pInfo->tx_buf)
1137    {
1138       printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
1139       kfree(pInfo->rx_buf);
1140       TRACE_M("r3964_open - rx_buf kfree %x",(int)pInfo->rx_buf);
1141       kfree(pInfo);
1142       TRACE_M("r3964_open - info kfree %x",(int)pInfo);
1143       return -ENOMEM;
1144    }
1145
1146    pInfo->tty = tty;
1147    init_waitqueue_head (&pInfo->read_wait);
1148    pInfo->priority = R3964_MASTER;
1149    pInfo->rx_first = pInfo->rx_last = NULL;
1150    pInfo->tx_first = pInfo->tx_last = NULL;
1151    pInfo->rx_position = 0;
1152    pInfo->tx_position = 0;
1153    pInfo->last_rx = 0;
1154    pInfo->blocks_in_rx_queue = 0;
1155    pInfo->firstClient=NULL;
1156    pInfo->state=R3964_IDLE;
1157    pInfo->flags = R3964_DEBUG;
1158    pInfo->count_down = 0;
1159    pInfo->nRetry = 0;
1160
1161    tty->disc_data = pInfo;
1162
1163    /*
1164     * Add 'on_timer' to timer task queue
1165     * (will be called from timer bh)
1166     */
1167    INIT_LIST_HEAD(&pInfo->bh_1.list);
1168    pInfo->bh_1.sync = 0;
1169    pInfo->bh_1.routine = &on_timer_1;
1170    pInfo->bh_1.data = pInfo;
1171
1172    INIT_LIST_HEAD(&pInfo->bh_2.list);
1173    pInfo->bh_2.sync = 0;
1174    pInfo->bh_2.routine = &on_timer_2;
1175    pInfo->bh_2.data = pInfo;
1176
1177    queue_task(&pInfo->bh_1, &tq_timer);
1178
1179    return 0;
1180 }
1181
1182 static void r3964_close(struct tty_struct *tty)
1183 {
1184    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1185    struct r3964_client_info *pClient, *pNext;
1186    struct r3964_message *pMsg;
1187    struct r3964_block_header *pHeader, *pNextHeader;
1188    unsigned long flags;
1189
1190    TRACE_L("close");
1191
1192     /*
1193      * Make sure that our task queue isn't activated.  If it
1194      * is, take it out of the linked list.
1195      */
1196     spin_lock_irqsave(&tqueue_lock, flags);
1197     if (pInfo->bh_1.sync)
1198         list_del(&pInfo->bh_1.list);
1199     if (pInfo->bh_2.sync)
1200         list_del(&pInfo->bh_2.list);
1201     spin_unlock_irqrestore(&tqueue_lock, flags);
1202
1203    /* Remove client-structs and message queues: */
1204     pClient=pInfo->firstClient;
1205     while(pClient)
1206     {
1207        pNext=pClient->next;
1208        while(pClient->msg_count)
1209        {
1210           pMsg=remove_msg(pInfo, pClient);
1211           if(pMsg)
1212           {
1213              kfree(pMsg);
1214              TRACE_M("r3964_close - msg kfree %x",(int)pMsg);
1215           }
1216        }
1217        kfree(pClient);
1218        TRACE_M("r3964_close - client kfree %x",(int)pClient);
1219        pClient=pNext;
1220     }
1221     /* Remove jobs from tx_queue: */
1222         save_flags(flags);
1223         cli();
1224         pHeader=pInfo->tx_first;
1225         pInfo->tx_first=pInfo->tx_last=NULL;
1226         restore_flags(flags);
1227
1228     while(pHeader)
1229         {
1230            pNextHeader=pHeader->next;
1231            kfree(pHeader);
1232            pHeader=pNextHeader;
1233         }
1234
1235     /* Free buffers: */
1236     wake_up_interruptible(&pInfo->read_wait);
1237     kfree(pInfo->rx_buf);
1238     TRACE_M("r3964_close - rx_buf kfree %x",(int)pInfo->rx_buf);
1239     kfree(pInfo->tx_buf);
1240     TRACE_M("r3964_close - tx_buf kfree %x",(int)pInfo->tx_buf);
1241     kfree(pInfo);
1242     TRACE_M("r3964_close - info kfree %x",(int)pInfo);
1243
1244     MOD_DEC_USE_COUNT;
1245 }
1246
1247 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1248                           unsigned char *buf, size_t nr)
1249 {
1250    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1251    struct r3964_client_info *pClient;
1252    struct r3964_message *pMsg;
1253    struct r3964_client_message theMsg;
1254    DECLARE_WAITQUEUE (wait, current);
1255
1256    int pid = current->pid;
1257    int count;
1258
1259    TRACE_L("read()");
1260
1261    pClient=findClient(pInfo, pid);
1262    if(pClient)
1263    {
1264       pMsg = remove_msg(pInfo, pClient);
1265       if(pMsg==NULL)
1266       {
1267                  /* no messages available. */
1268          if (file->f_flags & O_NONBLOCK)
1269                  {
1270             return -EAGAIN;
1271                  }
1272          /* block until there is a message: */
1273          add_wait_queue(&pInfo->read_wait, &wait);
1274 repeat:
1275          current->state = TASK_INTERRUPTIBLE;
1276          pMsg = remove_msg(pInfo, pClient);
1277          if (!pMsg && !signal_pending(current))
1278                  {
1279             schedule();
1280             goto repeat;
1281          }
1282          current->state = TASK_RUNNING;
1283          remove_wait_queue(&pInfo->read_wait, &wait);
1284       }
1285
1286       /* If we still haven't got a message, we must have been signalled */
1287
1288       if (!pMsg) return -EINTR;
1289
1290       /* deliver msg to client process: */
1291       theMsg.msg_id = pMsg->msg_id;
1292       theMsg.arg    = pMsg->arg;
1293       theMsg.error_code = pMsg->error_code;
1294       count = sizeof(struct r3964_client_message);
1295
1296       kfree(pMsg);
1297       TRACE_M("r3964_read - msg kfree %x",(int)pMsg);
1298
1299       if (copy_to_user(buf,&theMsg, count))
1300         return -EFAULT;
1301
1302       TRACE_PS("read - return %d", count);
1303       return count;
1304    }
1305    return -EPERM;
1306 }
1307
1308 static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
1309                            const unsigned char *data, size_t count)
1310 {
1311    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1312    struct r3964_block_header *pHeader;
1313    struct r3964_client_info *pClient;
1314    unsigned char *new_data;
1315    int status;
1316    int pid;
1317
1318    TRACE_L("write request, %d characters", count);
1319 /*
1320  * Verify the pointers
1321  */
1322
1323    if(!pInfo)
1324       return -EIO;
1325
1326    status = verify_area (VERIFY_READ, data, count);
1327    if (status != 0)
1328    {
1329       return status;
1330    }
1331
1332 /*
1333  * Ensure that the caller does not wish to send too much.
1334  */
1335    if (count > R3964_MTU)
1336    {
1337       if (pInfo->flags & R3964_DEBUG)
1338       {
1339          TRACE_L (KERN_WARNING
1340                  "r3964_write: truncating user packet "
1341                  "from %u to mtu %d", count, R3964_MTU);
1342       }
1343       count = R3964_MTU;
1344    }
1345 /*
1346  * Allocate a buffer for the data and fetch it from the user space.
1347  */
1348    new_data = kmalloc (count+sizeof(struct r3964_block_header), GFP_KERNEL);
1349    TRACE_M("r3964_write - kmalloc %x",(int)new_data);
1350    if (new_data == NULL) {
1351       if (pInfo->flags & R3964_DEBUG)
1352       {
1353          printk (KERN_ERR
1354                "r3964_write: no memory\n");
1355       }
1356       return -ENOSPC;
1357    }
1358
1359    pHeader = (struct r3964_block_header *)new_data;
1360    pHeader->data = new_data + sizeof(struct r3964_block_header);
1361    pHeader->length = count;
1362    pHeader->locks = 0;
1363    pHeader->owner = NULL;
1364
1365    pid=current->pid;
1366
1367    pClient=findClient(pInfo, pid);
1368    if(pClient)
1369    {
1370       pHeader->owner = pClient;
1371    }
1372
1373    __copy_from_user(pHeader->data, data, count); /* We already verified this */
1374
1375    if(pInfo->flags & R3964_DEBUG)
1376    {
1377       dump_block(pHeader->data, count);
1378    }
1379
1380 /*
1381  * Add buffer to transmit-queue:
1382  */
1383    add_tx_queue(pInfo, pHeader);
1384    trigger_transmit(pInfo);
1385
1386    return 0;
1387 }
1388
1389 static int r3964_ioctl(struct tty_struct * tty, struct file * file,
1390                unsigned int cmd, unsigned long arg)
1391 {
1392    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1393    if(pInfo==NULL)
1394       return -EINVAL;
1395    switch(cmd)
1396    {
1397       case R3964_ENABLE_SIGNALS:
1398          return enable_signals(pInfo, current->pid, arg);
1399       case R3964_SETPRIORITY:
1400          if(arg<R3964_MASTER || arg>R3964_SLAVE)
1401             return -EINVAL;
1402          pInfo->priority = arg & 0xff;
1403          return 0;
1404       case R3964_USE_BCC:
1405              if(arg)
1406             pInfo->flags |= R3964_BCC;
1407          else
1408             pInfo->flags &= ~R3964_BCC;
1409          return 0;
1410       case R3964_READ_TELEGRAM:
1411          return read_telegram(pInfo, current->pid, (unsigned char *)arg);
1412       default:
1413          return -ENOIOCTLCMD;
1414    }
1415 }
1416
1417 static void r3964_set_termios(struct tty_struct *tty, struct termios * old)
1418 {
1419    TRACE_L("set_termios");
1420 }
1421
1422 /* Called without the kernel lock held - fine */
1423 static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
1424                       struct poll_table_struct *wait)
1425 {
1426    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1427    int pid=current->pid;
1428    struct r3964_client_info *pClient;
1429    struct r3964_message *pMsg=NULL;
1430    unsigned long flags;
1431    int result = POLLOUT;
1432
1433    TRACE_L("POLL");
1434
1435    pClient=findClient(pInfo,pid);
1436    if(pClient)
1437      {
1438        poll_wait(file, &pInfo->read_wait, wait);
1439        save_flags(flags);
1440        cli();
1441        pMsg=pClient->first_msg;
1442        restore_flags(flags);
1443        if(pMsg)
1444            result |= POLLIN | POLLRDNORM;
1445      }
1446    else
1447      {
1448        result = -EINVAL;
1449      }
1450    return result;
1451 }
1452
1453 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1454                               char *fp, int count)
1455 {
1456    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1457     const unsigned char *p;
1458     char *f, flags = 0;
1459     int i;
1460
1461     for (i=count, p = cp, f = fp; i; i--, p++) {
1462         if (f)
1463             flags = *f++;
1464         if(flags==TTY_NORMAL)
1465         {
1466             receive_char(pInfo, *p);
1467         }
1468         else
1469         {
1470             receive_error(pInfo, flags);
1471         }
1472
1473     }
1474 }
1475
1476 static int r3964_receive_room(struct tty_struct *tty)
1477 {
1478    TRACE_L("receive_room");
1479    return -1;
1480 }
1481
1482
1483 MODULE_LICENSE("GPL");
1484
1485 EXPORT_NO_SYMBOLS;