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   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 1.10  2001/03/18 13:02:24  dwmw2
  17  * Fix timer usage, use spinlocks properly.
  18  *
  19  * Revision 1.9  2001/03/18 12:52:14  dwmw2
  20  * Merge changes in 2.4.2
  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 add_tx_queue(struct r3964_info *, struct r3964_block_header *);
 120 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
 121 static void put_char(struct r3964_info *pInfo, unsigned char ch);
 122 static void trigger_transmit(struct r3964_info *pInfo);
 123 static void retry_transmit(struct r3964_info *pInfo);
 124 static void transmit_block(struct r3964_info *pInfo);
 125 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
 126 static void receive_error(struct r3964_info *pInfo, const char flag);
 127 static void on_timeout(unsigned long priv);
 128 static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg);
 129 static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char __user *buf);
 130 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 131              int error_code, struct r3964_block_header *pBlock);
 132 static struct r3964_message* remove_msg(struct r3964_info *pInfo,
 133              struct r3964_client_info *pClient);
 134 static void remove_client_block(struct r3964_info *pInfo,
 135                 struct r3964_client_info *pClient);
 136
 137 static int  r3964_open(struct tty_struct *tty);
 138 static void r3964_close(struct tty_struct *tty);
 139 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
 140                      unsigned char __user *buf, size_t nr);
 141 static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
 142                       const unsigned char * buf, size_t nr);
 143 static int r3964_ioctl(struct tty_struct * tty, struct file * file,
 144                        unsigned int cmd, unsigned long arg);
 145 static void r3964_set_termios(struct tty_struct *tty, struct termios * old);
 146 static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
 147                       struct poll_table_struct  *wait);
 148 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 149                               char *fp, int count);
 150 static int  r3964_receive_room(struct tty_struct *tty);
 151
 152 static struct tty_ldisc tty_ldisc_N_R3964 = {
 153         .owner   = THIS_MODULE,
 154         .magic  = TTY_LDISC_MAGIC,
 155         .name   = "R3964",
 156         .open   = r3964_open,
 157         .close  = r3964_close,
 158         .read   = r3964_read,
 159         .write  = r3964_write,
 160         .ioctl  = r3964_ioctl,
 161         .set_termios = r3964_set_termios,
 162         .poll   = r3964_poll,
 163         .receive_buf = r3964_receive_buf,
 164         .receive_room = r3964_receive_room,
 165 };
 166
 167
 168
 169 static void dump_block(const unsigned char *block, unsigned int length)
 170 {
 171    unsigned int i,j;
 172    char linebuf[16*3+1];
 173
 174    for(i=0;i<length;i+=16)
 175    {
 176       for(j=0;(j<16) && (j+i<length);j++)
 177       {
 178          sprintf(linebuf+3*j,"%02x ",block[i+j]);
 179       }
 180       linebuf[3*j]='\0';
 181       TRACE_PS("%s",linebuf);
 182    }
 183 }
 184
 185
 186
 187
 188 /*************************************************************
 189  * Driver initialisation
 190  *************************************************************/
 191
 192
 193 /*************************************************************
 194  * Module support routines
 195  *************************************************************/
 196
 197 static void __exit r3964_exit(void)
 198 {
 199    int status;
 200
 201    TRACE_M ("cleanup_module()");
 202
 203    status=tty_unregister_ldisc(N_R3964);
 204
 205    if(status!=0)
 206    {
 207       printk(KERN_ERR "r3964: error unregistering linediscipline: %d\n", status);
 208    }
 209    else
 210    {
 211       TRACE_L("linediscipline successfully unregistered");
 212    }
 213
 214 }
 215
 216 static int __init r3964_init(void)
 217 {
 218    int status;
 219
 220    printk ("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
 221
 222    /*
 223     * Register the tty line discipline
 224     */
 225
 226    status = tty_register_ldisc (N_R3964, &tty_ldisc_N_R3964);
 227    if (status == 0)
 228      {
 229        TRACE_L("line discipline %d registered", N_R3964);
 230        TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 231                tty_ldisc_N_R3964.num);
 232        TRACE_L("open=%p", tty_ldisc_N_R3964.open);
 233        TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
 234      }
 235    else
 236      {
 237        printk (KERN_ERR "r3964: error registering line discipline: %d\n", status);
 238      }
 239    return status;
 240 }
 241
 242 module_init(r3964_init);
 243 module_exit(r3964_exit);
 244
 245
 246 /*************************************************************
 247  * Protocol implementation routines
 248  *************************************************************/
 249
 250 static void add_tx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
 251 {
 252    unsigned long flags;
 253
 254    spin_lock_irqsave(&pInfo->lock, flags);
 255
 256    pHeader->next = NULL;
 257
 258    if(pInfo->tx_last == NULL)
 259    {
 260       pInfo->tx_first = pInfo->tx_last = pHeader;
 261    }
 262    else
 263    {
 264       pInfo->tx_last->next = pHeader;
 265       pInfo->tx_last = pHeader;
 266    }
 267
 268    spin_unlock_irqrestore(&pInfo->lock, flags);
 269
 270    TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
 271           pHeader, pHeader->length, pInfo->tx_first );
 272 }
 273
 274 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 275 {
 276    struct r3964_block_header *pHeader;
 277    unsigned long flags;
 278 #ifdef DEBUG_QUEUE
 279    struct r3964_block_header *pDump;
 280 #endif
 281
 282    pHeader = pInfo->tx_first;
 283
 284    if(pHeader==NULL)
 285       return;
 286
 287 #ifdef DEBUG_QUEUE
 288    printk("r3964: remove_from_tx_queue: %p, length %u - ",
 289           pHeader, pHeader->length );
 290    for(pDump=pHeader;pDump;pDump=pDump->next)
 291          printk("%p ", pDump);
 292    printk("\n");
 293 #endif
 294
 295
 296    if(pHeader->owner)
 297    {
 298       if(error_code)
 299       {
 300           add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 301                   error_code, NULL);
 302       }
 303       else
 304       {
 305           add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 306                   error_code, NULL);
 307       }
 308       wake_up_interruptible (&pInfo->read_wait);
 309    }
 310
 311    spin_lock_irqsave(&pInfo->lock, flags);
 312
 313    pInfo->tx_first = pHeader->next;
 314    if(pInfo->tx_first==NULL)
 315    {
 316       pInfo->tx_last = NULL;
 317    }
 318
 319    spin_unlock_irqrestore(&pInfo->lock, flags);
 320
 321    kfree(pHeader);
 322    TRACE_M("remove_from_tx_queue - kfree %p",pHeader);
 323
 324    TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
 325           pInfo->tx_first, pInfo->tx_last );
 326 }
 327
 328 static void add_rx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
 329 {
 330    unsigned long flags;
 331
 332    spin_lock_irqsave(&pInfo->lock, flags);
 333
 334    pHeader->next = NULL;
 335
 336    if(pInfo->rx_last == NULL)
 337    {
 338       pInfo->rx_first = pInfo->rx_last = pHeader;
 339    }
 340    else
 341    {
 342       pInfo->rx_last->next = pHeader;
 343       pInfo->rx_last = pHeader;
 344    }
 345    pInfo->blocks_in_rx_queue++;
 346
 347    spin_unlock_irqrestore(&pInfo->lock, flags);
 348
 349    TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
 350           pHeader, pHeader->length,
 351           pInfo->rx_first, pInfo->blocks_in_rx_queue);
 352 }
 353
 354 static void remove_from_rx_queue(struct r3964_info *pInfo,
 355                  struct r3964_block_header *pHeader)
 356 {
 357    unsigned long flags;
 358    struct r3964_block_header *pFind;
 359
 360    if(pHeader==NULL)
 361       return;
 362
 363    TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 364           pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue );
 365    TRACE_Q("remove_from_rx_queue: %p, length %u",
 366           pHeader, pHeader->length );
 367
 368    spin_lock_irqsave(&pInfo->lock, flags);
 369
 370    if(pInfo->rx_first == pHeader)
 371    {
 372       /* Remove the first block in the linked list: */
 373       pInfo->rx_first = pHeader->next;
 374
 375       if(pInfo->rx_first==NULL)
 376       {
 377          pInfo->rx_last = NULL;
 378       }
 379       pInfo->blocks_in_rx_queue--;
 380    }
 381    else
 382    {
 383       /* Find block to remove: */
 384       for(pFind=pInfo->rx_first; pFind; pFind=pFind->next)
 385       {
 386          if(pFind->next == pHeader)
 387          {
 388             /* Got it. */
 389             pFind->next = pHeader->next;
 390             pInfo->blocks_in_rx_queue--;
 391             if(pFind->next==NULL)
 392             {
 393                /* Oh, removed the last one! */
 394                pInfo->rx_last = pFind;
 395             }
 396             break;
 397          }
 398       }
 399    }
 400
 401    spin_unlock_irqrestore(&pInfo->lock, flags);
 402
 403    kfree(pHeader);
 404    TRACE_M("remove_from_rx_queue - kfree %p",pHeader);
 405
 406    TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 407           pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue );
 408 }
 409
 410 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 411 {
 412    struct tty_struct *tty = pInfo->tty;
 413
 414    if(tty==NULL)
 415       return;
 416
 417    if(tty->driver->put_char)
 418    {
 419       tty->driver->put_char(tty, ch);
 420    }
 421    pInfo->bcc ^= ch;
 422 }
 423
 424 static void flush(struct r3964_info *pInfo)
 425 {
 426    struct tty_struct *tty = pInfo->tty;
 427
 428    if(tty==NULL)
 429       return;
 430
 431    if(tty->driver->flush_chars)
 432    {
 433       tty->driver->flush_chars(tty);
 434    }
 435 }
 436
 437 static void trigger_transmit(struct r3964_info *pInfo)
 438 {
 439    unsigned long flags;
 440
 441
 442    spin_lock_irqsave(&pInfo->lock, flags);
 443
 444    if((pInfo->state == R3964_IDLE) && (pInfo->tx_first!=NULL))
 445    {
 446       pInfo->state = R3964_TX_REQUEST;
 447       pInfo->nRetry=0;
 448       pInfo->flags &= ~R3964_ERROR;
 449       mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 450
 451       spin_unlock_irqrestore(&pInfo->lock, flags);
 452
 453       TRACE_PS("trigger_transmit - sent STX");
 454
 455       put_char(pInfo, STX);
 456       flush(pInfo);
 457
 458       pInfo->bcc = 0;
 459    }
 460    else
 461    {
 462       spin_unlock_irqrestore(&pInfo->lock, flags);
 463    }
 464 }
 465
 466 static void retry_transmit(struct r3964_info *pInfo)
 467 {
 468    if(pInfo->nRetry<R3964_MAX_RETRIES)
 469    {
 470       TRACE_PE("transmission failed. Retry #%d",
 471              pInfo->nRetry);
 472       pInfo->bcc = 0;
 473       put_char(pInfo, STX);
 474       flush(pInfo);
 475       pInfo->state = R3964_TX_REQUEST;
 476       pInfo->nRetry++;
 477       mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 478    }
 479    else
 480    {
 481       TRACE_PE("transmission failed after %d retries",
 482              R3964_MAX_RETRIES);
 483
 484       remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 485
 486       put_char(pInfo, NAK);
 487       flush(pInfo);
 488       pInfo->state = R3964_IDLE;
 489
 490       trigger_transmit(pInfo);
 491    }
 492 }
 493
 494
 495 static void transmit_block(struct r3964_info *pInfo)
 496 {
 497    struct tty_struct *tty = pInfo->tty;
 498    struct r3964_block_header *pBlock = pInfo->tx_first;
 499    int room=0;
 500
 501    if((tty==NULL) || (pBlock==NULL))
 502    {
 503       return;
 504    }
 505
 506    if(tty->driver->write_room)
 507       room=tty->driver->write_room(tty);
 508
 509    TRACE_PS("transmit_block %p, room %d, length %d",
 510           pBlock, room, pBlock->length);
 511
 512    while(pInfo->tx_position < pBlock->length)
 513    {
 514       if(room<2)
 515          break;
 516
 517       if(pBlock->data[pInfo->tx_position]==DLE)
 518       {
 519          /* send additional DLE char: */
 520          put_char(pInfo, DLE);
 521       }
 522       put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 523
 524       room--;
 525    }
 526
 527    if((pInfo->tx_position == pBlock->length) && (room>=3))
 528    {
 529       put_char(pInfo, DLE);
 530       put_char(pInfo, ETX);
 531       if(pInfo->flags & R3964_BCC)
 532       {
 533          put_char(pInfo, pInfo->bcc);
 534       }
 535       pInfo->state = R3964_WAIT_FOR_TX_ACK;
 536       mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 537    }
 538    flush(pInfo);
 539 }
 540
 541 static void on_receive_block(struct r3964_info *pInfo)
 542 {
 543    unsigned int length;
 544    struct r3964_client_info *pClient;
 545    struct r3964_block_header *pBlock;
 546
 547    length=pInfo->rx_position;
 548
 549    /* compare byte checksum characters: */
 550    if(pInfo->flags & R3964_BCC)
 551    {
 552       if(pInfo->bcc!=pInfo->last_rx)
 553       {
 554          TRACE_PE("checksum error - got %x but expected %x",
 555                 pInfo->last_rx, pInfo->bcc);
 556          pInfo->flags |= R3964_CHECKSUM;
 557       }
 558    }
 559
 560    /* check for errors (parity, overrun,...): */
 561    if(pInfo->flags & R3964_ERROR)
 562    {
 563       TRACE_PE("on_receive_block - transmission failed error %x",
 564              pInfo->flags & R3964_ERROR);
 565
 566       put_char(pInfo, NAK);
 567       flush(pInfo);
 568       if(pInfo->nRetry<R3964_MAX_RETRIES)
 569       {
 570          pInfo->state=R3964_WAIT_FOR_RX_REPEAT;
 571          pInfo->nRetry++;
 572          mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 573       }
 574       else
 575       {
 576          TRACE_PE("on_receive_block - failed after max retries");
 577          pInfo->state=R3964_IDLE;
 578       }
 579       return;
 580    }
 581
 582
 583    /* received block; submit DLE: */
 584    put_char(pInfo, DLE);
 585    flush(pInfo);
 586    del_timer_sync(&pInfo->tmr);
 587    TRACE_PS(" rx success: got %d chars", length);
 588
 589    /* prepare struct r3964_block_header: */
 590    pBlock = kmalloc(length+sizeof(struct r3964_block_header), GFP_KERNEL);
 591    TRACE_M("on_receive_block - kmalloc %p",pBlock);
 592
 593    if(pBlock==NULL)
 594       return;
 595
 596    pBlock->length = length;
 597    pBlock->data   = ((unsigned char*)pBlock)+sizeof(struct r3964_block_header);
 598    pBlock->locks  = 0;
 599    pBlock->next   = NULL;
 600    pBlock->owner  = NULL;
 601
 602    memcpy(pBlock->data, pInfo->rx_buf, length);
 603
 604    /* queue block into rx_queue: */
 605    add_rx_queue(pInfo, pBlock);
 606
 607    /* notify attached client processes: */
 608    for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
 609    {
 610       if(pClient->sig_flags & R3964_SIG_DATA)
 611       {
 612          add_msg(pClient, R3964_MSG_DATA, length, R3964_OK, pBlock);
 613       }
 614    }
 615    wake_up_interruptible (&pInfo->read_wait);
 616
 617    pInfo->state = R3964_IDLE;
 618
 619    trigger_transmit(pInfo);
 620 }
 621
 622
 623 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 624 {
 625    switch(pInfo->state)
 626    {
 627       case R3964_TX_REQUEST:
 628          if(c==DLE)
 629          {
 630             TRACE_PS("TX_REQUEST - got DLE");
 631
 632             pInfo->state = R3964_TRANSMITTING;
 633             pInfo->tx_position = 0;
 634
 635             transmit_block(pInfo);
 636          }
 637          else if(c==STX)
 638          {
 639             if(pInfo->nRetry==0)
 640             {
 641                TRACE_PE("TX_REQUEST - init conflict");
 642                if(pInfo->priority == R3964_SLAVE)
 643                {
 644                   goto start_receiving;
 645                }
 646             }
 647             else
 648             {
 649                TRACE_PE("TX_REQUEST - secondary init conflict!?"
 650                         " Switching to SLAVE mode for next rx.");
 651                goto start_receiving;
 652             }
 653          }
 654          else
 655          {
 656             TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 657             retry_transmit(pInfo);
 658          }
 659          break;
 660       case R3964_TRANSMITTING:
 661          if(c==NAK)
 662          {
 663             TRACE_PE("TRANSMITTING - got NAK");
 664             retry_transmit(pInfo);
 665          }
 666          else
 667          {
 668             TRACE_PE("TRANSMITTING - got invalid char");
 669
 670             pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 671             mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 672          }
 673          break;
 674       case R3964_WAIT_FOR_TX_ACK:
 675          if(c==DLE)
 676          {
 677             TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 678             remove_from_tx_queue(pInfo, R3964_OK);
 679
 680             pInfo->state = R3964_IDLE;
 681             trigger_transmit(pInfo);
 682          }
 683          else
 684          {
 685             retry_transmit(pInfo);
 686          }
 687          break;
 688       case R3964_WAIT_FOR_RX_REPEAT:
 689          /* FALLTROUGH */
 690       case R3964_IDLE:
 691          if(c==STX)
 692          {
 693             /* Prevent rx_queue from overflow: */
 694             if(pInfo->blocks_in_rx_queue >= R3964_MAX_BLOCKS_IN_RX_QUEUE)
 695             {
 696                TRACE_PE("IDLE - got STX but no space in rx_queue!");
 697                pInfo->state=R3964_WAIT_FOR_RX_BUF;
 698                mod_timer(&pInfo->tmr, jiffies + R3964_TO_NO_BUF);
 699                break;
 700             }
 701 start_receiving:
 702             /* Ok, start receiving: */
 703             TRACE_PS("IDLE - got STX");
 704             pInfo->rx_position = 0;
 705             pInfo->last_rx = 0;
 706             pInfo->flags &= ~R3964_ERROR;
 707             pInfo->state=R3964_RECEIVING;
 708             mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 709             pInfo->nRetry = 0;
 710             put_char(pInfo, DLE);
 711             flush(pInfo);
 712             pInfo->bcc = 0;
 713          }
 714          break;
 715       case R3964_RECEIVING:
 716          if(pInfo->rx_position < RX_BUF_SIZE)
 717          {
 718             pInfo->bcc ^= c;
 719
 720             if(c==DLE)
 721             {
 722                if(pInfo->last_rx==DLE)
 723                {
 724                   pInfo->last_rx = 0;
 725                   goto char_to_buf;
 726                }
 727                pInfo->last_rx = DLE;
 728                break;
 729             }
 730             else if((c==ETX) && (pInfo->last_rx==DLE))
 731             {
 732                if(pInfo->flags & R3964_BCC)
 733                {
 734                   pInfo->state = R3964_WAIT_FOR_BCC;
 735                   mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 736                }
 737                else
 738                {
 739                   on_receive_block(pInfo);
 740                }
 741             }
 742             else
 743             {
 744                pInfo->last_rx = c;
 745 char_to_buf:
 746                pInfo->rx_buf[pInfo->rx_position++] = c;
 747                mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 748             }
 749          }
 750         /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 751          break;
 752       case R3964_WAIT_FOR_BCC:
 753          pInfo->last_rx = c;
 754          on_receive_block(pInfo);
 755          break;
 756    }
 757 }
 758
 759 static void receive_error(struct r3964_info *pInfo, const char flag)
 760 {
 761     switch (flag)
 762     {
 763     case TTY_NORMAL:
 764         break;
 765     case TTY_BREAK:
 766         TRACE_PE("received break")
 767         pInfo->flags |= R3964_BREAK;
 768         break;
 769     case TTY_PARITY:
 770         TRACE_PE("parity error")
 771         pInfo->flags |= R3964_PARITY;
 772         break;
 773     case TTY_FRAME:
 774         TRACE_PE("frame error")
 775         pInfo->flags |= R3964_FRAME;
 776         break;
 777     case TTY_OVERRUN:
 778         TRACE_PE("frame overrun")
 779         pInfo->flags |= R3964_OVERRUN;
 780         break;
 781     default:
 782         TRACE_PE("receive_error - unknown flag %d", flag);
 783         pInfo->flags |= R3964_UNKNOWN;
 784         break;
 785     }
 786 }
 787
 788 static void on_timeout(unsigned long priv)
 789 {
 790    struct r3964_info *pInfo = (void *)priv;
 791
 792    switch(pInfo->state)
 793    {
 794       case R3964_TX_REQUEST:
 795          TRACE_PE("TX_REQUEST - timeout");
 796          retry_transmit(pInfo);
 797          break;
 798       case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 799          put_char(pInfo, NAK);
 800          flush(pInfo);
 801          retry_transmit(pInfo);
 802          break;
 803       case R3964_WAIT_FOR_TX_ACK:
 804          TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 805          retry_transmit(pInfo);
 806          break;
 807       case R3964_WAIT_FOR_RX_BUF:
 808          TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 809          put_char(pInfo, NAK);
 810          flush(pInfo);
 811          pInfo->state=R3964_IDLE;
 812          break;
 813       case R3964_RECEIVING:
 814          TRACE_PE("RECEIVING - timeout after %d chars",
 815                   pInfo->rx_position);
 816          put_char(pInfo, NAK);
 817          flush(pInfo);
 818          pInfo->state=R3964_IDLE;
 819          break;
 820       case R3964_WAIT_FOR_RX_REPEAT:
 821          TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 822          pInfo->state=R3964_IDLE;
 823          break;
 824       case R3964_WAIT_FOR_BCC:
 825          TRACE_PE("WAIT_FOR_BCC - timeout");
 826          put_char(pInfo, NAK);
 827          flush(pInfo);
 828          pInfo->state=R3964_IDLE;
 829          break;
 830    }
 831 }
 832
 833 static struct r3964_client_info *findClient(
 834   struct r3964_info *pInfo, pid_t pid)
 835 {
 836    struct r3964_client_info *pClient;
 837
 838    for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
 839    {
 840       if(pClient->pid == pid)
 841       {
 842          return pClient;
 843       }
 844    }
 845    return NULL;
 846 }
 847
 848 static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg)
 849 {
 850    struct r3964_client_info *pClient;
 851    struct r3964_client_info **ppClient;
 852    struct r3964_message *pMsg;
 853
 854    if((arg & R3964_SIG_ALL)==0)
 855    {
 856       /* Remove client from client list */
 857       for(ppClient=&pInfo->firstClient; *ppClient; ppClient=&(*ppClient)->next)
 858       {
 859          pClient = *ppClient;
 860
 861          if(pClient->pid == pid)
 862          {
 863             TRACE_PS("removing client %d from client list", pid);
 864             *ppClient = pClient->next;
 865             while(pClient->msg_count)
 866             {
 867                pMsg=remove_msg(pInfo, pClient);
 868                if(pMsg)
 869                {
 870                   kfree(pMsg);
 871                   TRACE_M("enable_signals - msg kfree %p",pMsg);
 872                }
 873             }
 874             kfree(pClient);
 875             TRACE_M("enable_signals - kfree %p",pClient);
 876             return 0;
 877          }
 878       }
 879       return -EINVAL;
 880    }
 881    else
 882    {
 883       pClient=findClient(pInfo, pid);
 884       if(pClient)
 885       {
 886          /* update signal options */
 887          pClient->sig_flags=arg;
 888       }
 889       else
 890       {
 891          /* add client to client list */
 892          pClient=kmalloc(sizeof(struct r3964_client_info), GFP_KERNEL);
 893          TRACE_M("enable_signals - kmalloc %p",pClient);
 894          if(pClient==NULL)
 895             return -ENOMEM;
 896
 897          TRACE_PS("add client %d to client list", pid);
 898          spin_lock_init(&pClient->lock);
 899          pClient->sig_flags=arg;
 900          pClient->pid = pid;
 901          pClient->next=pInfo->firstClient;
 902          pClient->first_msg = NULL;
 903          pClient->last_msg = NULL;
 904          pClient->next_block_to_read = NULL;
 905          pClient->msg_count = 0;
 906          pInfo->firstClient=pClient;
 907       }
 908    }
 909
 910    return 0;
 911 }
 912
 913 static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char __user *buf)
 914 {
 915     struct r3964_client_info *pClient;
 916     struct r3964_block_header *block;
 917
 918     if(!buf)
 919     {
 920         return -EINVAL;
 921     }
 922
 923     pClient=findClient(pInfo,pid);
 924     if(pClient==NULL)
 925     {
 926        return -EINVAL;
 927     }
 928
 929     block=pClient->next_block_to_read;
 930     if(!block)
 931     {
 932        return 0;
 933     }
 934     else
 935     {
 936       if (copy_to_user (buf, block->data, block->length))
 937         return -EFAULT;
 938
 939        remove_client_block(pInfo, pClient);
 940        return block->length;
 941     }
 942
 943     return -EINVAL;
 944 }
 945
 946 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 947              int error_code, struct r3964_block_header *pBlock)
 948 {
 949    struct r3964_message *pMsg;
 950    unsigned long flags;
 951
 952    if(pClient->msg_count<R3964_MAX_MSG_COUNT-1)
 953    {
 954 queue_the_message:
 955
 956       pMsg = kmalloc(sizeof(struct r3964_message), GFP_KERNEL);
 957       TRACE_M("add_msg - kmalloc %p",pMsg);
 958       if(pMsg==NULL) {
 959          return;
 960       }
 961
 962       spin_lock_irqsave(&pClient->lock, flags);
 963
 964       pMsg->msg_id = msg_id;
 965       pMsg->arg    = arg;
 966       pMsg->error_code = error_code;
 967       pMsg->block  = pBlock;
 968       pMsg->next   = NULL;
 969
 970       if(pClient->last_msg==NULL)
 971       {
 972          pClient->first_msg=pClient->last_msg=pMsg;
 973       }
 974       else
 975       {
 976          pClient->last_msg->next = pMsg;
 977          pClient->last_msg=pMsg;
 978       }
 979
 980       pClient->msg_count++;
 981
 982       if(pBlock!=NULL)
 983       {
 984          pBlock->locks++;
 985       }
 986       spin_unlock_irqrestore(&pClient->lock, flags);
 987    }
 988    else
 989    {
 990       if((pClient->last_msg->msg_id == R3964_MSG_ACK)
 991                  && (pClient->last_msg->error_code==R3964_OVERFLOW))
 992       {
 993          pClient->last_msg->arg++;
 994                  TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 995       }
 996       else
 997       {
 998          msg_id = R3964_MSG_ACK;
 999          arg = 0;
1000                  error_code = R3964_OVERFLOW;
1001          pBlock = NULL;
1002                  TRACE_PE("add_msg - queue OVERFLOW-msg");
1003          goto queue_the_message;
1004       }
1005    }
1006    /* Send SIGIO signal to client process: */
1007    if(pClient->sig_flags & R3964_USE_SIGIO)
1008    {
1009       kill_proc(pClient->pid, SIGIO, 1);
1010    }
1011 }
1012
1013 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
1014                        struct r3964_client_info *pClient)
1015 {
1016    struct r3964_message *pMsg=NULL;
1017    unsigned long flags;
1018
1019    if(pClient->first_msg)
1020    {
1021       spin_lock_irqsave(&pClient->lock, flags);
1022
1023       pMsg = pClient->first_msg;
1024       pClient->first_msg = pMsg->next;
1025       if(pClient->first_msg==NULL)
1026       {
1027          pClient->last_msg = NULL;
1028       }
1029
1030       pClient->msg_count--;
1031       if(pMsg->block)
1032       {
1033         remove_client_block(pInfo, pClient);
1034         pClient->next_block_to_read = pMsg->block;
1035       }
1036       spin_unlock_irqrestore(&pClient->lock, flags);
1037    }
1038    return pMsg;
1039 }
1040
1041 static void remove_client_block(struct r3964_info *pInfo,
1042                 struct r3964_client_info *pClient)
1043 {
1044     struct r3964_block_header *block;
1045
1046     TRACE_PS("remove_client_block PID %d", pClient->pid);
1047
1048     block=pClient->next_block_to_read;
1049     if(block)
1050     {
1051         block->locks--;
1052         if(block->locks==0)
1053         {
1054             remove_from_rx_queue(pInfo, block);
1055         }
1056     }
1057     pClient->next_block_to_read = NULL;
1058 }
1059
1060
1061 /*************************************************************
1062  * Line discipline routines
1063  *************************************************************/
1064
1065 static int r3964_open(struct tty_struct *tty)
1066 {
1067    struct r3964_info *pInfo;
1068
1069    TRACE_L("open");
1070    TRACE_L("tty=%p, PID=%d, disc_data=%p",
1071           tty, current->pid, tty->disc_data);
1072
1073    pInfo=kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
1074    TRACE_M("r3964_open - info kmalloc %p",pInfo);
1075
1076    if(!pInfo)
1077    {
1078       printk(KERN_ERR "r3964: failed to alloc info structure\n");
1079       return -ENOMEM;
1080    }
1081
1082    pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
1083    TRACE_M("r3964_open - rx_buf kmalloc %p",pInfo->rx_buf);
1084
1085    if(!pInfo->rx_buf)
1086    {
1087       printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
1088       kfree(pInfo);
1089       TRACE_M("r3964_open - info kfree %p",pInfo);
1090       return -ENOMEM;
1091    }
1092
1093    pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
1094    TRACE_M("r3964_open - tx_buf kmalloc %p",pInfo->tx_buf);
1095
1096    if(!pInfo->tx_buf)
1097    {
1098       printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
1099       kfree(pInfo->rx_buf);
1100       TRACE_M("r3964_open - rx_buf kfree %p",pInfo->rx_buf);
1101       kfree(pInfo);
1102       TRACE_M("r3964_open - info kfree %p",pInfo);
1103       return -ENOMEM;
1104    }
1105
1106    spin_lock_init(&pInfo->lock);
1107    pInfo->tty = tty;
1108    init_waitqueue_head (&pInfo->read_wait);
1109    pInfo->priority = R3964_MASTER;
1110    pInfo->rx_first = pInfo->rx_last = NULL;
1111    pInfo->tx_first = pInfo->tx_last = NULL;
1112    pInfo->rx_position = 0;
1113    pInfo->tx_position = 0;
1114    pInfo->last_rx = 0;
1115    pInfo->blocks_in_rx_queue = 0;
1116    pInfo->firstClient=NULL;
1117    pInfo->state=R3964_IDLE;
1118    pInfo->flags = R3964_DEBUG;
1119    pInfo->nRetry = 0;
1120
1121    tty->disc_data = pInfo;
1122
1123    init_timer(&pInfo->tmr);
1124    pInfo->tmr.data = (unsigned long)pInfo;
1125    pInfo->tmr.function = on_timeout;
1126
1127    return 0;
1128 }
1129
1130 static void r3964_close(struct tty_struct *tty)
1131 {
1132    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1133    struct r3964_client_info *pClient, *pNext;
1134    struct r3964_message *pMsg;
1135    struct r3964_block_header *pHeader, *pNextHeader;
1136    unsigned long flags;
1137
1138    TRACE_L("close");
1139
1140     /*
1141      * Make sure that our task queue isn't activated.  If it
1142      * is, take it out of the linked list.
1143      */
1144     del_timer_sync(&pInfo->tmr);
1145
1146    /* Remove client-structs and message queues: */
1147     pClient=pInfo->firstClient;
1148     while(pClient)
1149     {
1150        pNext=pClient->next;
1151        while(pClient->msg_count)
1152        {
1153           pMsg=remove_msg(pInfo, pClient);
1154           if(pMsg)
1155           {
1156              kfree(pMsg);
1157              TRACE_M("r3964_close - msg kfree %p",pMsg);
1158           }
1159        }
1160        kfree(pClient);
1161        TRACE_M("r3964_close - client kfree %p",pClient);
1162        pClient=pNext;
1163     }
1164     /* Remove jobs from tx_queue: */
1165         spin_lock_irqsave(&pInfo->lock, flags);
1166         pHeader=pInfo->tx_first;
1167         pInfo->tx_first=pInfo->tx_last=NULL;
1168         spin_unlock_irqrestore(&pInfo->lock, flags);
1169
1170     while(pHeader)
1171         {
1172            pNextHeader=pHeader->next;
1173            kfree(pHeader);
1174            pHeader=pNextHeader;
1175         }
1176
1177     /* Free buffers: */
1178     wake_up_interruptible(&pInfo->read_wait);
1179     kfree(pInfo->rx_buf);
1180     TRACE_M("r3964_close - rx_buf kfree %p",pInfo->rx_buf);
1181     kfree(pInfo->tx_buf);
1182     TRACE_M("r3964_close - tx_buf kfree %p",pInfo->tx_buf);
1183     kfree(pInfo);
1184     TRACE_M("r3964_close - info kfree %p",pInfo);
1185 }
1186
1187 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1188                           unsigned char __user *buf, size_t nr)
1189 {
1190    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1191    struct r3964_client_info *pClient;
1192    struct r3964_message *pMsg;
1193    struct r3964_client_message theMsg;
1194    DECLARE_WAITQUEUE (wait, current);
1195
1196    int pid = current->pid;
1197    int count;
1198
1199    TRACE_L("read()");
1200
1201    pClient=findClient(pInfo, pid);
1202    if(pClient)
1203    {
1204       pMsg = remove_msg(pInfo, pClient);
1205       if(pMsg==NULL)
1206       {
1207                  /* no messages available. */
1208          if (file->f_flags & O_NONBLOCK)
1209                  {
1210             return -EAGAIN;
1211                  }
1212          /* block until there is a message: */
1213          add_wait_queue(&pInfo->read_wait, &wait);
1214 repeat:
1215          current->state = TASK_INTERRUPTIBLE;
1216          pMsg = remove_msg(pInfo, pClient);
1217          if (!pMsg && !signal_pending(current))
1218                  {
1219             schedule();
1220             goto repeat;
1221          }
1222          current->state = TASK_RUNNING;
1223          remove_wait_queue(&pInfo->read_wait, &wait);
1224       }
1225
1226       /* If we still haven't got a message, we must have been signalled */
1227
1228       if (!pMsg) return -EINTR;
1229
1230       /* deliver msg to client process: */
1231       theMsg.msg_id = pMsg->msg_id;
1232       theMsg.arg    = pMsg->arg;
1233       theMsg.error_code = pMsg->error_code;
1234       count = sizeof(struct r3964_client_message);
1235
1236       kfree(pMsg);
1237       TRACE_M("r3964_read - msg kfree %p",pMsg);
1238
1239       if (copy_to_user(buf,&theMsg, count))
1240         return -EFAULT;
1241
1242       TRACE_PS("read - return %d", count);
1243       return count;
1244    }
1245    return -EPERM;
1246 }
1247
1248 static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
1249                            const unsigned char *data, size_t count)
1250 {
1251    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1252    struct r3964_block_header *pHeader;
1253    struct r3964_client_info *pClient;
1254    unsigned char *new_data;
1255    int pid;
1256
1257    TRACE_L("write request, %d characters", count);
1258 /*
1259  * Verify the pointers
1260  */
1261
1262    if(!pInfo)
1263       return -EIO;
1264
1265 /*
1266  * Ensure that the caller does not wish to send too much.
1267  */
1268    if (count > R3964_MTU)
1269    {
1270       if (pInfo->flags & R3964_DEBUG)
1271       {
1272          TRACE_L (KERN_WARNING
1273                  "r3964_write: truncating user packet "
1274                  "from %u to mtu %d", count, R3964_MTU);
1275       }
1276       count = R3964_MTU;
1277    }
1278 /*
1279  * Allocate a buffer for the data and copy it from the buffer with header prepended
1280  */
1281    new_data = kmalloc (count+sizeof(struct r3964_block_header), GFP_KERNEL);
1282    TRACE_M("r3964_write - kmalloc %p",new_data);
1283    if (new_data == NULL) {
1284       if (pInfo->flags & R3964_DEBUG)
1285       {
1286          printk (KERN_ERR
1287                "r3964_write: no memory\n");
1288       }
1289       return -ENOSPC;
1290    }
1291
1292    pHeader = (struct r3964_block_header *)new_data;
1293    pHeader->data = new_data + sizeof(struct r3964_block_header);
1294    pHeader->length = count;
1295    pHeader->locks = 0;
1296    pHeader->owner = NULL;
1297
1298    pid=current->pid;
1299
1300    pClient=findClient(pInfo, pid);
1301    if(pClient)
1302    {
1303       pHeader->owner = pClient;
1304    }
1305
1306    memcpy(pHeader->data, data, count); /* We already verified this */
1307
1308    if(pInfo->flags & R3964_DEBUG)
1309    {
1310       dump_block(pHeader->data, count);
1311    }
1312
1313 /*
1314  * Add buffer to transmit-queue:
1315  */
1316    add_tx_queue(pInfo, pHeader);
1317    trigger_transmit(pInfo);
1318
1319    return 0;
1320 }
1321
1322 static int r3964_ioctl(struct tty_struct * tty, struct file * file,
1323                unsigned int cmd, unsigned long arg)
1324 {
1325    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1326    if(pInfo==NULL)
1327       return -EINVAL;
1328    switch(cmd)
1329    {
1330       case R3964_ENABLE_SIGNALS:
1331          return enable_signals(pInfo, current->pid, arg);
1332       case R3964_SETPRIORITY:
1333          if(arg<R3964_MASTER || arg>R3964_SLAVE)
1334             return -EINVAL;
1335          pInfo->priority = arg & 0xff;
1336          return 0;
1337       case R3964_USE_BCC:
1338              if(arg)
1339             pInfo->flags |= R3964_BCC;
1340          else
1341             pInfo->flags &= ~R3964_BCC;
1342          return 0;
1343       case R3964_READ_TELEGRAM:
1344          return read_telegram(pInfo, current->pid, (unsigned char __user *)arg);
1345       default:
1346          return -ENOIOCTLCMD;
1347    }
1348 }
1349
1350 static void r3964_set_termios(struct tty_struct *tty, struct termios * old)
1351 {
1352    TRACE_L("set_termios");
1353 }
1354
1355 /* Called without the kernel lock held - fine */
1356 static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
1357                       struct poll_table_struct *wait)
1358 {
1359    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1360    int pid=current->pid;
1361    struct r3964_client_info *pClient;
1362    struct r3964_message *pMsg=NULL;
1363    unsigned long flags;
1364    int result = POLLOUT;
1365
1366    TRACE_L("POLL");
1367
1368    pClient=findClient(pInfo,pid);
1369    if(pClient)
1370      {
1371        poll_wait(file, &pInfo->read_wait, wait);
1372        spin_lock_irqsave(&pInfo->lock, flags);
1373        pMsg=pClient->first_msg;
1374        spin_unlock_irqrestore(&pInfo->lock, flags);
1375        if(pMsg)
1376            result |= POLLIN | POLLRDNORM;
1377      }
1378    else
1379      {
1380        result = -EINVAL;
1381      }
1382    return result;
1383 }
1384
1385 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1386                               char *fp, int count)
1387 {
1388    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1389     const unsigned char *p;
1390     char *f, flags = 0;
1391     int i;
1392
1393     for (i=count, p = cp, f = fp; i; i--, p++) {
1394         if (f)
1395             flags = *f++;
1396         if(flags==TTY_NORMAL)
1397         {
1398             receive_char(pInfo, *p);
1399         }
1400         else
1401         {
1402             receive_error(pInfo, flags);
1403         }
1404
1405     }
1406 }
1407
1408 static int r3964_receive_room(struct tty_struct *tty)
1409 {
1410    TRACE_L("receive_room");
1411    return -1;
1412 }
1413
1414
1415 MODULE_LICENSE("GPL");
1416 MODULE_ALIAS_LDISC(N_R3964);