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 1.10  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 *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 *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         TTY_LDISC_MAGIC,       /* magic */
 154         "R3964",               /* name */
 155         0,                     /* num */
 156         0,                     /* flags */
 157         r3964_open,            /* open */
 158         r3964_close,           /* close */
 159         0,                     /* flush_buffer */
 160         0,                     /* chars_in_buffer */
 161         r3964_read,            /* read */
 162         r3964_write,           /* write */
 163         r3964_ioctl,           /* ioctl */
 164         r3964_set_termios,     /* set_termios */
 165         r3964_poll,            /* poll */
 166         r3964_receive_buf,     /* receive_buf */
 167         r3964_receive_room,    /* receive_room */
 168         0                      /* write_wakeup */
 169 };
 170
 171
 172
 173 static void dump_block(const unsigned char *block, unsigned int length)
 174 {
 175    unsigned int i,j;
 176    char linebuf[16*3+1];
 177
 178    for(i=0;i<length;i+=16)
 179    {
 180       for(j=0;(j<16) && (j+i<length);j++)
 181       {
 182          sprintf(linebuf+3*j,"%02x ",block[i+j]);
 183       }
 184       linebuf[3*j]='\0';
 185       TRACE_PS("%s",linebuf);
 186    }
 187 }
 188
 189
 190
 191
 192 /*************************************************************
 193  * Driver initialisation
 194  *************************************************************/
 195
 196
 197 /*************************************************************
 198  * Module support routines
 199  *************************************************************/
 200
 201 static void __exit r3964_exit(void)
 202 {
 203    int status;
 204
 205    TRACE_M ("cleanup_module()");
 206
 207    status=tty_register_ldisc(N_R3964, NULL);
 208
 209    if(status!=0)
 210    {
 211       printk(KERN_ERR "r3964: error unregistering linediscipline: %d\n", status);
 212    }
 213    else
 214    {
 215       TRACE_L("linediscipline successfully unregistered");
 216    }
 217
 218 }
 219
 220 static int __init r3964_init(void)
 221 {
 222    int status;
 223
 224    printk ("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
 225
 226    /*
 227     * Register the tty line discipline
 228     */
 229
 230    status = tty_register_ldisc (N_R3964, &tty_ldisc_N_R3964);
 231    if (status == 0)
 232      {
 233        TRACE_L("line discipline %d registered", N_R3964);
 234        TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 235                tty_ldisc_N_R3964.num);
 236        TRACE_L("open=%x", (int)tty_ldisc_N_R3964.open);
 237        TRACE_L("tty_ldisc_N_R3964 = %x", (int)&tty_ldisc_N_R3964);
 238      }
 239    else
 240      {
 241        printk (KERN_ERR "r3964: error registering line discipline: %d\n", status);
 242      }
 243    return status;
 244 }
 245
 246 module_init(r3964_init);
 247 module_exit(r3964_exit);
 248
 249
 250 /*************************************************************
 251  * Protocol implementation routines
 252  *************************************************************/
 253
 254 static void add_tx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
 255 {
 256    unsigned long flags;
 257
 258    spin_lock_irqsave(&pInfo->lock, flags);
 259
 260    pHeader->next = NULL;
 261
 262    if(pInfo->tx_last == NULL)
 263    {
 264       pInfo->tx_first = pInfo->tx_last = pHeader;
 265    }
 266    else
 267    {
 268       pInfo->tx_last->next = pHeader;
 269       pInfo->tx_last = pHeader;
 270    }
 271
 272    spin_unlock_irqrestore(&pInfo->lock, flags);
 273
 274    TRACE_Q("add_tx_queue %x, length %d, tx_first = %x",
 275           (int)pHeader, pHeader->length, (int)pInfo->tx_first );
 276 }
 277
 278 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 279 {
 280    struct r3964_block_header *pHeader;
 281    unsigned long flags;
 282 #ifdef DEBUG_QUEUE
 283    struct r3964_block_header *pDump;
 284 #endif
 285
 286    pHeader = pInfo->tx_first;
 287
 288    if(pHeader==NULL)
 289       return;
 290
 291 #ifdef DEBUG_QUEUE
 292    printk("r3964: remove_from_tx_queue: %x, length %d - ",
 293           (int)pHeader, (int)pHeader->length );
 294    for(pDump=pHeader;pDump;pDump=pDump->next)
 295          printk("%x ", (int)pDump);
 296    printk("\n");
 297 #endif
 298
 299
 300    if(pHeader->owner)
 301    {
 302       if(error_code)
 303       {
 304           add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 305                   error_code, NULL);
 306       }
 307       else
 308       {
 309           add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 310                   error_code, NULL);
 311       }
 312       wake_up_interruptible (&pInfo->read_wait);
 313    }
 314
 315    spin_lock_irqsave(&pInfo->lock, flags);
 316
 317    pInfo->tx_first = pHeader->next;
 318    if(pInfo->tx_first==NULL)
 319    {
 320       pInfo->tx_last = NULL;
 321    }
 322
 323    spin_unlock_irqrestore(&pInfo->lock, flags);
 324
 325    kfree(pHeader);
 326    TRACE_M("remove_from_tx_queue - kfree %x",(int)pHeader);
 327
 328    TRACE_Q("remove_from_tx_queue: tx_first = %x, tx_last = %x",
 329           (int)pInfo->tx_first, (int)pInfo->tx_last );
 330 }
 331
 332 static void add_rx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
 333 {
 334    unsigned long flags;
 335
 336    spin_lock_irqsave(&pInfo->lock, flags);
 337
 338    pHeader->next = NULL;
 339
 340    if(pInfo->rx_last == NULL)
 341    {
 342       pInfo->rx_first = pInfo->rx_last = pHeader;
 343    }
 344    else
 345    {
 346       pInfo->rx_last->next = pHeader;
 347       pInfo->rx_last = pHeader;
 348    }
 349    pInfo->blocks_in_rx_queue++;
 350
 351    spin_unlock_irqrestore(&pInfo->lock, flags);
 352
 353    TRACE_Q("add_rx_queue: %x, length = %d, rx_first = %x, count = %d",
 354           (int)pHeader, pHeader->length,
 355           (int)pInfo->rx_first, pInfo->blocks_in_rx_queue);
 356 }
 357
 358 static void remove_from_rx_queue(struct r3964_info *pInfo,
 359                  struct r3964_block_header *pHeader)
 360 {
 361    unsigned long flags;
 362    struct r3964_block_header *pFind;
 363
 364    if(pHeader==NULL)
 365       return;
 366
 367    TRACE_Q("remove_from_rx_queue: rx_first = %x, rx_last = %x, count = %d",
 368           (int)pInfo->rx_first, (int)pInfo->rx_last, pInfo->blocks_in_rx_queue );
 369    TRACE_Q("remove_from_rx_queue: %x, length %d",
 370           (int)pHeader, (int)pHeader->length );
 371
 372    spin_lock_irqsave(&pInfo->lock, flags);
 373
 374    if(pInfo->rx_first == pHeader)
 375    {
 376       /* Remove the first block in the linked list: */
 377       pInfo->rx_first = pHeader->next;
 378
 379       if(pInfo->rx_first==NULL)
 380       {
 381          pInfo->rx_last = NULL;
 382       }
 383       pInfo->blocks_in_rx_queue--;
 384    }
 385    else
 386    {
 387       /* Find block to remove: */
 388       for(pFind=pInfo->rx_first; pFind; pFind=pFind->next)
 389       {
 390          if(pFind->next == pHeader)
 391          {
 392             /* Got it. */
 393             pFind->next = pHeader->next;
 394             pInfo->blocks_in_rx_queue--;
 395             if(pFind->next==NULL)
 396             {
 397                /* Oh, removed the last one! */
 398                pInfo->rx_last = pFind;
 399             }
 400             break;
 401          }
 402       }
 403    }
 404
 405    spin_unlock_irqrestore(&pInfo->lock, flags);
 406
 407    kfree(pHeader);
 408    TRACE_M("remove_from_rx_queue - kfree %x",(int)pHeader);
 409
 410    TRACE_Q("remove_from_rx_queue: rx_first = %x, rx_last = %x, count = %d",
 411           (int)pInfo->rx_first, (int)pInfo->rx_last, pInfo->blocks_in_rx_queue );
 412 }
 413
 414 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 415 {
 416    struct tty_struct *tty = pInfo->tty;
 417
 418    if(tty==NULL)
 419       return;
 420
 421    if(tty->driver->put_char)
 422    {
 423       tty->driver->put_char(tty, ch);
 424    }
 425    pInfo->bcc ^= ch;
 426 }
 427
 428 static void flush(struct r3964_info *pInfo)
 429 {
 430    struct tty_struct *tty = pInfo->tty;
 431
 432    if(tty==NULL)
 433       return;
 434
 435    if(tty->driver->flush_chars)
 436    {
 437       tty->driver->flush_chars(tty);
 438    }
 439 }
 440
 441 static void trigger_transmit(struct r3964_info *pInfo)
 442 {
 443    unsigned long flags;
 444
 445
 446    spin_lock_irqsave(&pInfo->lock, flags);
 447
 448    if((pInfo->state == R3964_IDLE) && (pInfo->tx_first!=NULL))
 449    {
 450       pInfo->state = R3964_TX_REQUEST;
 451       pInfo->nRetry=0;
 452       pInfo->flags &= ~R3964_ERROR;
 453       mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 454
 455       spin_unlock_irqrestore(&pInfo->lock, flags);
 456
 457       TRACE_PS("trigger_transmit - sent STX");
 458
 459       put_char(pInfo, STX);
 460       flush(pInfo);
 461
 462       pInfo->bcc = 0;
 463    }
 464    else
 465    {
 466       spin_unlock_irqrestore(&pInfo->lock, flags);
 467    }
 468 }
 469
 470 static void retry_transmit(struct r3964_info *pInfo)
 471 {
 472    if(pInfo->nRetry<R3964_MAX_RETRIES)
 473    {
 474       TRACE_PE("transmission failed. Retry #%d",
 475              pInfo->nRetry);
 476       pInfo->bcc = 0;
 477       put_char(pInfo, STX);
 478       flush(pInfo);
 479       pInfo->state = R3964_TX_REQUEST;
 480       pInfo->nRetry++;
 481       mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 482    }
 483    else
 484    {
 485       TRACE_PE("transmission failed after %d retries",
 486              R3964_MAX_RETRIES);
 487
 488       remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 489
 490       put_char(pInfo, NAK);
 491       flush(pInfo);
 492       pInfo->state = R3964_IDLE;
 493
 494       trigger_transmit(pInfo);
 495    }
 496 }
 497
 498
 499 static void transmit_block(struct r3964_info *pInfo)
 500 {
 501    struct tty_struct *tty = pInfo->tty;
 502    struct r3964_block_header *pBlock = pInfo->tx_first;
 503    int room=0;
 504
 505    if((tty==NULL) || (pBlock==NULL))
 506    {
 507       return;
 508    }
 509
 510    if(tty->driver->write_room)
 511       room=tty->driver->write_room(tty);
 512
 513    TRACE_PS("transmit_block %x, room %d, length %d",
 514           (int)pBlock, room, pBlock->length);
 515
 516    while(pInfo->tx_position < pBlock->length)
 517    {
 518       if(room<2)
 519          break;
 520
 521       if(pBlock->data[pInfo->tx_position]==DLE)
 522       {
 523          /* send additional DLE char: */
 524          put_char(pInfo, DLE);
 525       }
 526       put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 527
 528       room--;
 529    }
 530
 531    if((pInfo->tx_position == pBlock->length) && (room>=3))
 532    {
 533       put_char(pInfo, DLE);
 534       put_char(pInfo, ETX);
 535       if(pInfo->flags & R3964_BCC)
 536       {
 537          put_char(pInfo, pInfo->bcc);
 538       }
 539       pInfo->state = R3964_WAIT_FOR_TX_ACK;
 540       mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 541    }
 542    flush(pInfo);
 543 }
 544
 545 static void on_receive_block(struct r3964_info *pInfo)
 546 {
 547    unsigned int length;
 548    struct r3964_client_info *pClient;
 549    struct r3964_block_header *pBlock;
 550
 551    length=pInfo->rx_position;
 552
 553    /* compare byte checksum characters: */
 554    if(pInfo->flags & R3964_BCC)
 555    {
 556       if(pInfo->bcc!=pInfo->last_rx)
 557       {
 558          TRACE_PE("checksum error - got %x but expected %x",
 559                 pInfo->last_rx, pInfo->bcc);
 560          pInfo->flags |= R3964_CHECKSUM;
 561       }
 562    }
 563
 564    /* check for errors (parity, overrun,...): */
 565    if(pInfo->flags & R3964_ERROR)
 566    {
 567       TRACE_PE("on_receive_block - transmission failed error %x",
 568              pInfo->flags & R3964_ERROR);
 569
 570       put_char(pInfo, NAK);
 571       flush(pInfo);
 572       if(pInfo->nRetry<R3964_MAX_RETRIES)
 573       {
 574          pInfo->state=R3964_WAIT_FOR_RX_REPEAT;
 575          pInfo->nRetry++;
 576          mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 577       }
 578       else
 579       {
 580          TRACE_PE("on_receive_block - failed after max retries");
 581          pInfo->state=R3964_IDLE;
 582       }
 583       return;
 584    }
 585
 586
 587    /* received block; submit DLE: */
 588    put_char(pInfo, DLE);
 589    flush(pInfo);
 590    del_timer_sync(&pInfo->tmr);
 591    TRACE_PS(" rx success: got %d chars", length);
 592
 593    /* prepare struct r3964_block_header: */
 594    pBlock = kmalloc(length+sizeof(struct r3964_block_header), GFP_KERNEL);
 595    TRACE_M("on_receive_block - kmalloc %x",(int)pBlock);
 596
 597    if(pBlock==NULL)
 598       return;
 599
 600    pBlock->length = length;
 601    pBlock->data   = ((unsigned char*)pBlock)+sizeof(struct r3964_block_header);
 602    pBlock->locks  = 0;
 603    pBlock->next   = NULL;
 604    pBlock->owner  = NULL;
 605
 606    memcpy(pBlock->data, pInfo->rx_buf, length);
 607
 608    /* queue block into rx_queue: */
 609    add_rx_queue(pInfo, pBlock);
 610
 611    /* notify attached client processes: */
 612    for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
 613    {
 614       if(pClient->sig_flags & R3964_SIG_DATA)
 615       {
 616          add_msg(pClient, R3964_MSG_DATA, length, R3964_OK, pBlock);
 617       }
 618    }
 619    wake_up_interruptible (&pInfo->read_wait);
 620
 621    pInfo->state = R3964_IDLE;
 622
 623    trigger_transmit(pInfo);
 624 }
 625
 626
 627 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 628 {
 629    switch(pInfo->state)
 630    {
 631       case R3964_TX_REQUEST:
 632          if(c==DLE)
 633          {
 634             TRACE_PS("TX_REQUEST - got DLE");
 635
 636             pInfo->state = R3964_TRANSMITTING;
 637             pInfo->tx_position = 0;
 638
 639             transmit_block(pInfo);
 640          }
 641          else if(c==STX)
 642          {
 643             if(pInfo->nRetry==0)
 644             {
 645                TRACE_PE("TX_REQUEST - init conflict");
 646                if(pInfo->priority == R3964_SLAVE)
 647                {
 648                   goto start_receiving;
 649                }
 650             }
 651             else
 652             {
 653                TRACE_PE("TX_REQUEST - secondary init conflict!?"
 654                         " Switching to SLAVE mode for next rx.");
 655                goto start_receiving;
 656             }
 657          }
 658          else
 659          {
 660             TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 661             retry_transmit(pInfo);
 662          }
 663          break;
 664       case R3964_TRANSMITTING:
 665          if(c==NAK)
 666          {
 667             TRACE_PE("TRANSMITTING - got NAK");
 668             retry_transmit(pInfo);
 669          }
 670          else
 671          {
 672             TRACE_PE("TRANSMITTING - got invalid char");
 673
 674             pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 675             mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 676          }
 677          break;
 678       case R3964_WAIT_FOR_TX_ACK:
 679          if(c==DLE)
 680          {
 681             TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 682             remove_from_tx_queue(pInfo, R3964_OK);
 683
 684             pInfo->state = R3964_IDLE;
 685             trigger_transmit(pInfo);
 686          }
 687          else
 688          {
 689             retry_transmit(pInfo);
 690          }
 691          break;
 692       case R3964_WAIT_FOR_RX_REPEAT:
 693          /* FALLTROUGH */
 694       case R3964_IDLE:
 695          if(c==STX)
 696          {
 697             /* Prevent rx_queue from overflow: */
 698             if(pInfo->blocks_in_rx_queue >= R3964_MAX_BLOCKS_IN_RX_QUEUE)
 699             {
 700                TRACE_PE("IDLE - got STX but no space in rx_queue!");
 701                pInfo->state=R3964_WAIT_FOR_RX_BUF;
 702                mod_timer(&pInfo->tmr, R3964_TO_NO_BUF);
 703                break;
 704             }
 705 start_receiving:
 706             /* Ok, start receiving: */
 707             TRACE_PS("IDLE - got STX");
 708             pInfo->rx_position = 0;
 709             pInfo->last_rx = 0;
 710             pInfo->flags &= ~R3964_ERROR;
 711             pInfo->state=R3964_RECEIVING;
 712             mod_timer(&pInfo->tmr, R3964_TO_ZVZ);
 713             pInfo->nRetry = 0;
 714             put_char(pInfo, DLE);
 715             flush(pInfo);
 716             pInfo->bcc = 0;
 717          }
 718          break;
 719       case R3964_RECEIVING:
 720          if(pInfo->rx_position < RX_BUF_SIZE)
 721          {
 722             pInfo->bcc ^= c;
 723
 724             if(c==DLE)
 725             {
 726                if(pInfo->last_rx==DLE)
 727                {
 728                   pInfo->last_rx = 0;
 729                   goto char_to_buf;
 730                }
 731                pInfo->last_rx = DLE;
 732                break;
 733             }
 734             else if((c==ETX) && (pInfo->last_rx==DLE))
 735             {
 736                if(pInfo->flags & R3964_BCC)
 737                {
 738                   pInfo->state = R3964_WAIT_FOR_BCC;
 739                   mod_timer(&pInfo->tmr, R3964_TO_ZVZ);
 740                }
 741                else
 742                {
 743                   on_receive_block(pInfo);
 744                }
 745             }
 746             else
 747             {
 748                pInfo->last_rx = c;
 749 char_to_buf:
 750                pInfo->rx_buf[pInfo->rx_position++] = c;
 751                mod_timer(&pInfo->tmr, R3964_TO_ZVZ);
 752             }
 753          }
 754         /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 755          break;
 756       case R3964_WAIT_FOR_BCC:
 757          pInfo->last_rx = c;
 758          on_receive_block(pInfo);
 759          break;
 760    }
 761 }
 762
 763 static void receive_error(struct r3964_info *pInfo, const char flag)
 764 {
 765     switch (flag)
 766     {
 767     case TTY_NORMAL:
 768         break;
 769     case TTY_BREAK:
 770         TRACE_PE("received break")
 771         pInfo->flags |= R3964_BREAK;
 772         break;
 773     case TTY_PARITY:
 774         TRACE_PE("parity error")
 775         pInfo->flags |= R3964_PARITY;
 776         break;
 777     case TTY_FRAME:
 778         TRACE_PE("frame error")
 779         pInfo->flags |= R3964_FRAME;
 780         break;
 781     case TTY_OVERRUN:
 782         TRACE_PE("frame overrun")
 783         pInfo->flags |= R3964_OVERRUN;
 784         break;
 785     default:
 786         TRACE_PE("receive_error - unknown flag %d", flag);
 787         pInfo->flags |= R3964_UNKNOWN;
 788         break;
 789     }
 790 }
 791
 792 static void on_timeout(unsigned long priv)
 793 {
 794    struct r3964_info *pInfo = (void *)priv;
 795
 796    switch(pInfo->state)
 797    {
 798       case R3964_TX_REQUEST:
 799          TRACE_PE("TX_REQUEST - timeout");
 800          retry_transmit(pInfo);
 801          break;
 802       case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 803          put_char(pInfo, NAK);
 804          flush(pInfo);
 805          retry_transmit(pInfo);
 806          break;
 807       case R3964_WAIT_FOR_TX_ACK:
 808          TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 809          retry_transmit(pInfo);
 810          break;
 811       case R3964_WAIT_FOR_RX_BUF:
 812          TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 813          put_char(pInfo, NAK);
 814          flush(pInfo);
 815          pInfo->state=R3964_IDLE;
 816          break;
 817       case R3964_RECEIVING:
 818          TRACE_PE("RECEIVING - timeout after %d chars",
 819                   pInfo->rx_position);
 820          put_char(pInfo, NAK);
 821          flush(pInfo);
 822          pInfo->state=R3964_IDLE;
 823          break;
 824       case R3964_WAIT_FOR_RX_REPEAT:
 825          TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 826          pInfo->state=R3964_IDLE;
 827          break;
 828       case R3964_WAIT_FOR_BCC:
 829          TRACE_PE("WAIT_FOR_BCC - timeout");
 830          put_char(pInfo, NAK);
 831          flush(pInfo);
 832          pInfo->state=R3964_IDLE;
 833          break;
 834    }
 835 }
 836
 837 static struct r3964_client_info *findClient(
 838   struct r3964_info *pInfo, pid_t pid)
 839 {
 840    struct r3964_client_info *pClient;
 841
 842    for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
 843    {
 844       if(pClient->pid == pid)
 845       {
 846          return pClient;
 847       }
 848    }
 849    return NULL;
 850 }
 851
 852 static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg)
 853 {
 854    struct r3964_client_info *pClient;
 855    struct r3964_client_info **ppClient;
 856    struct r3964_message *pMsg;
 857
 858    if((arg & R3964_SIG_ALL)==0)
 859    {
 860       /* Remove client from client list */
 861       for(ppClient=&pInfo->firstClient; *ppClient; ppClient=&(*ppClient)->next)
 862       {
 863          pClient = *ppClient;
 864
 865          if(pClient->pid == pid)
 866          {
 867             TRACE_PS("removing client %d from client list", pid);
 868             *ppClient = pClient->next;
 869             while(pClient->msg_count)
 870             {
 871                pMsg=remove_msg(pInfo, pClient);
 872                if(pMsg)
 873                {
 874                   kfree(pMsg);
 875                   TRACE_M("enable_signals - msg kfree %x",(int)pMsg);
 876                }
 877             }
 878             kfree(pClient);
 879             TRACE_M("enable_signals - kfree %x",(int)pClient);
 880             return 0;
 881          }
 882       }
 883       return -EINVAL;
 884    }
 885    else
 886    {
 887       pClient=findClient(pInfo, pid);
 888       if(pClient)
 889       {
 890          /* update signal options */
 891          pClient->sig_flags=arg;
 892       }
 893       else
 894       {
 895          /* add client to client list */
 896          pClient=kmalloc(sizeof(struct r3964_client_info), GFP_KERNEL);
 897          TRACE_M("enable_signals - kmalloc %x",(int)pClient);
 898          if(pClient==NULL)
 899             return -ENOMEM;
 900
 901          TRACE_PS("add client %d to client list", pid);
 902          spin_lock_init(&pClient->lock);
 903          pClient->sig_flags=arg;
 904          pClient->pid = pid;
 905          pClient->next=pInfo->firstClient;
 906          pClient->first_msg = NULL;
 907          pClient->last_msg = NULL;
 908          pClient->next_block_to_read = NULL;
 909          pClient->msg_count = 0;
 910          pInfo->firstClient=pClient;
 911       }
 912    }
 913
 914    return 0;
 915 }
 916
 917 static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char *buf)
 918 {
 919     struct r3964_client_info *pClient;
 920     struct r3964_block_header *block;
 921
 922     if(!buf)
 923     {
 924         return -EINVAL;
 925     }
 926
 927     pClient=findClient(pInfo,pid);
 928     if(pClient==NULL)
 929     {
 930        return -EINVAL;
 931     }
 932
 933     block=pClient->next_block_to_read;
 934     if(!block)
 935     {
 936        return 0;
 937     }
 938     else
 939     {
 940       if (copy_to_user (buf, block->data, block->length))
 941         return -EFAULT;
 942
 943        remove_client_block(pInfo, pClient);
 944        return block->length;
 945     }
 946
 947     return -EINVAL;
 948 }
 949
 950 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 951              int error_code, struct r3964_block_header *pBlock)
 952 {
 953    struct r3964_message *pMsg;
 954    unsigned long flags;
 955
 956    if(pClient->msg_count<R3964_MAX_MSG_COUNT-1)
 957    {
 958 queue_the_message:
 959
 960       pMsg = kmalloc(sizeof(struct r3964_message), GFP_KERNEL);
 961       TRACE_M("add_msg - kmalloc %x",(int)pMsg);
 962       if(pMsg==NULL) {
 963          return;
 964       }
 965
 966       spin_lock_irqsave(&pClient->lock, flags);
 967
 968       pMsg->msg_id = msg_id;
 969       pMsg->arg    = arg;
 970       pMsg->error_code = error_code;
 971       pMsg->block  = pBlock;
 972       pMsg->next   = NULL;
 973
 974       if(pClient->last_msg==NULL)
 975       {
 976          pClient->first_msg=pClient->last_msg=pMsg;
 977       }
 978       else
 979       {
 980          pClient->last_msg->next = pMsg;
 981          pClient->last_msg=pMsg;
 982       }
 983
 984       pClient->msg_count++;
 985
 986       if(pBlock!=NULL)
 987       {
 988          pBlock->locks++;
 989       }
 990       spin_unlock_irqrestore(&pClient->lock, flags);
 991    }
 992    else
 993    {
 994       if((pClient->last_msg->msg_id == R3964_MSG_ACK)
 995                  && (pClient->last_msg->error_code==R3964_OVERFLOW))
 996       {
 997          pClient->last_msg->arg++;
 998                  TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 999       }
1000       else
1001       {
1002          msg_id = R3964_MSG_ACK;
1003          arg = 0;
1004                  error_code = R3964_OVERFLOW;
1005          pBlock = NULL;
1006                  TRACE_PE("add_msg - queue OVERFLOW-msg");
1007          goto queue_the_message;
1008       }
1009    }
1010    /* Send SIGIO signal to client process: */
1011    if(pClient->sig_flags & R3964_USE_SIGIO)
1012    {
1013       kill_proc(pClient->pid, SIGIO, 1);
1014    }
1015 }
1016
1017 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
1018                        struct r3964_client_info *pClient)
1019 {
1020    struct r3964_message *pMsg=NULL;
1021    unsigned long flags;
1022
1023    if(pClient->first_msg)
1024    {
1025       spin_lock_irqsave(&pClient->lock, flags);
1026
1027       pMsg = pClient->first_msg;
1028       pClient->first_msg = pMsg->next;
1029       if(pClient->first_msg==NULL)
1030       {
1031          pClient->last_msg = NULL;
1032       }
1033
1034       pClient->msg_count--;
1035       if(pMsg->block)
1036       {
1037         remove_client_block(pInfo, pClient);
1038         pClient->next_block_to_read = pMsg->block;
1039       }
1040       spin_unlock_irqrestore(&pClient->lock, flags);
1041    }
1042    return pMsg;
1043 }
1044
1045 static void remove_client_block(struct r3964_info *pInfo,
1046                 struct r3964_client_info *pClient)
1047 {
1048     struct r3964_block_header *block;
1049
1050     TRACE_PS("remove_client_block PID %d", pClient->pid);
1051
1052     block=pClient->next_block_to_read;
1053     if(block)
1054     {
1055         block->locks--;
1056         if(block->locks==0)
1057         {
1058             remove_from_rx_queue(pInfo, block);
1059         }
1060     }
1061     pClient->next_block_to_read = NULL;
1062 }
1063
1064
1065 /*************************************************************
1066  * Line discipline routines
1067  *************************************************************/
1068
1069 static int r3964_open(struct tty_struct *tty)
1070 {
1071    struct r3964_info *pInfo;
1072
1073    MOD_INC_USE_COUNT;
1074
1075    TRACE_L("open");
1076    TRACE_L("tty=%x, PID=%d, disc_data=%x",
1077           (int)tty, current->pid, (int)tty->disc_data);
1078
1079    pInfo=kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
1080    TRACE_M("r3964_open - info kmalloc %x",(int)pInfo);
1081
1082    if(!pInfo)
1083    {
1084       printk(KERN_ERR "r3964: failed to alloc info structure\n");
1085       return -ENOMEM;
1086    }
1087
1088    pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
1089    TRACE_M("r3964_open - rx_buf kmalloc %x",(int)pInfo->rx_buf);
1090
1091    if(!pInfo->rx_buf)
1092    {
1093       printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
1094       kfree(pInfo);
1095       TRACE_M("r3964_open - info kfree %x",(int)pInfo);
1096       return -ENOMEM;
1097    }
1098
1099    pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
1100    TRACE_M("r3964_open - tx_buf kmalloc %x",(int)pInfo->tx_buf);
1101
1102    if(!pInfo->tx_buf)
1103    {
1104       printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
1105       kfree(pInfo->rx_buf);
1106       TRACE_M("r3964_open - rx_buf kfree %x",(int)pInfo->rx_buf);
1107       kfree(pInfo);
1108       TRACE_M("r3964_open - info kfree %x",(int)pInfo);
1109       return -ENOMEM;
1110    }
1111
1112    spin_lock_init(&pInfo->lock);
1113    pInfo->tty = tty;
1114    init_waitqueue_head (&pInfo->read_wait);
1115    pInfo->priority = R3964_MASTER;
1116    pInfo->rx_first = pInfo->rx_last = NULL;
1117    pInfo->tx_first = pInfo->tx_last = NULL;
1118    pInfo->rx_position = 0;
1119    pInfo->tx_position = 0;
1120    pInfo->last_rx = 0;
1121    pInfo->blocks_in_rx_queue = 0;
1122    pInfo->firstClient=NULL;
1123    pInfo->state=R3964_IDLE;
1124    pInfo->flags = R3964_DEBUG;
1125    pInfo->nRetry = 0;
1126
1127    tty->disc_data = pInfo;
1128
1129    init_timer(&pInfo->tmr);
1130    pInfo->tmr.data = (unsigned long)pInfo;
1131    pInfo->tmr.function = on_timeout;
1132
1133    return 0;
1134 }
1135
1136 static void r3964_close(struct tty_struct *tty)
1137 {
1138    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1139    struct r3964_client_info *pClient, *pNext;
1140    struct r3964_message *pMsg;
1141    struct r3964_block_header *pHeader, *pNextHeader;
1142    unsigned long flags;
1143
1144    TRACE_L("close");
1145
1146     /*
1147      * Make sure that our task queue isn't activated.  If it
1148      * is, take it out of the linked list.
1149      */
1150     del_timer_sync(&pInfo->tmr);
1151
1152    /* Remove client-structs and message queues: */
1153     pClient=pInfo->firstClient;
1154     while(pClient)
1155     {
1156        pNext=pClient->next;
1157        while(pClient->msg_count)
1158        {
1159           pMsg=remove_msg(pInfo, pClient);
1160           if(pMsg)
1161           {
1162              kfree(pMsg);
1163              TRACE_M("r3964_close - msg kfree %x",(int)pMsg);
1164           }
1165        }
1166        kfree(pClient);
1167        TRACE_M("r3964_close - client kfree %x",(int)pClient);
1168        pClient=pNext;
1169     }
1170     /* Remove jobs from tx_queue: */
1171         spin_lock_irqsave(&pInfo->lock, flags);
1172         pHeader=pInfo->tx_first;
1173         pInfo->tx_first=pInfo->tx_last=NULL;
1174         spin_unlock_irqrestore(&pInfo->lock, flags);
1175
1176     while(pHeader)
1177         {
1178            pNextHeader=pHeader->next;
1179            kfree(pHeader);
1180            pHeader=pNextHeader;
1181         }
1182
1183     /* Free buffers: */
1184     wake_up_interruptible(&pInfo->read_wait);
1185     kfree(pInfo->rx_buf);
1186     TRACE_M("r3964_close - rx_buf kfree %x",(int)pInfo->rx_buf);
1187     kfree(pInfo->tx_buf);
1188     TRACE_M("r3964_close - tx_buf kfree %x",(int)pInfo->tx_buf);
1189     kfree(pInfo);
1190     TRACE_M("r3964_close - info kfree %x",(int)pInfo);
1191
1192     MOD_DEC_USE_COUNT;
1193 }
1194
1195 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1196                           unsigned char *buf, size_t nr)
1197 {
1198    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1199    struct r3964_client_info *pClient;
1200    struct r3964_message *pMsg;
1201    struct r3964_client_message theMsg;
1202    DECLARE_WAITQUEUE (wait, current);
1203
1204    int pid = current->pid;
1205    int count;
1206
1207    TRACE_L("read()");
1208
1209    pClient=findClient(pInfo, pid);
1210    if(pClient)
1211    {
1212       pMsg = remove_msg(pInfo, pClient);
1213       if(pMsg==NULL)
1214       {
1215                  /* no messages available. */
1216          if (file->f_flags & O_NONBLOCK)
1217                  {
1218             return -EAGAIN;
1219                  }
1220          /* block until there is a message: */
1221          add_wait_queue(&pInfo->read_wait, &wait);
1222 repeat:
1223          current->state = TASK_INTERRUPTIBLE;
1224          pMsg = remove_msg(pInfo, pClient);
1225          if (!pMsg && !signal_pending(current))
1226                  {
1227             schedule();
1228             goto repeat;
1229          }
1230          current->state = TASK_RUNNING;
1231          remove_wait_queue(&pInfo->read_wait, &wait);
1232       }
1233
1234       /* If we still haven't got a message, we must have been signalled */
1235
1236       if (!pMsg) return -EINTR;
1237
1238       /* deliver msg to client process: */
1239       theMsg.msg_id = pMsg->msg_id;
1240       theMsg.arg    = pMsg->arg;
1241       theMsg.error_code = pMsg->error_code;
1242       count = sizeof(struct r3964_client_message);
1243
1244       kfree(pMsg);
1245       TRACE_M("r3964_read - msg kfree %x",(int)pMsg);
1246
1247       if (copy_to_user(buf,&theMsg, count))
1248         return -EFAULT;
1249
1250       TRACE_PS("read - return %d", count);
1251       return count;
1252    }
1253    return -EPERM;
1254 }
1255
1256 static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
1257                            const unsigned char *data, size_t count)
1258 {
1259    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1260    struct r3964_block_header *pHeader;
1261    struct r3964_client_info *pClient;
1262    unsigned char *new_data;
1263    int status;
1264    int pid;
1265
1266    TRACE_L("write request, %d characters", count);
1267 /*
1268  * Verify the pointers
1269  */
1270
1271    if(!pInfo)
1272       return -EIO;
1273
1274    status = verify_area (VERIFY_READ, data, count);
1275    if (status != 0)
1276    {
1277       return status;
1278    }
1279
1280 /*
1281  * Ensure that the caller does not wish to send too much.
1282  */
1283    if (count > R3964_MTU)
1284    {
1285       if (pInfo->flags & R3964_DEBUG)
1286       {
1287          TRACE_L (KERN_WARNING
1288                  "r3964_write: truncating user packet "
1289                  "from %u to mtu %d", count, R3964_MTU);
1290       }
1291       count = R3964_MTU;
1292    }
1293 /*
1294  * Allocate a buffer for the data and fetch it from the user space.
1295  */
1296    new_data = kmalloc (count+sizeof(struct r3964_block_header), GFP_KERNEL);
1297    TRACE_M("r3964_write - kmalloc %x",(int)new_data);
1298    if (new_data == NULL) {
1299       if (pInfo->flags & R3964_DEBUG)
1300       {
1301          printk (KERN_ERR
1302                "r3964_write: no memory\n");
1303       }
1304       return -ENOSPC;
1305    }
1306
1307    pHeader = (struct r3964_block_header *)new_data;
1308    pHeader->data = new_data + sizeof(struct r3964_block_header);
1309    pHeader->length = count;
1310    pHeader->locks = 0;
1311    pHeader->owner = NULL;
1312
1313    pid=current->pid;
1314
1315    pClient=findClient(pInfo, pid);
1316    if(pClient)
1317    {
1318       pHeader->owner = pClient;
1319    }
1320
1321    __copy_from_user(pHeader->data, data, count); /* We already verified this */
1322
1323    if(pInfo->flags & R3964_DEBUG)
1324    {
1325       dump_block(pHeader->data, count);
1326    }
1327
1328 /*
1329  * Add buffer to transmit-queue:
1330  */
1331    add_tx_queue(pInfo, pHeader);
1332    trigger_transmit(pInfo);
1333
1334    return 0;
1335 }
1336
1337 static int r3964_ioctl(struct tty_struct * tty, struct file * file,
1338                unsigned int cmd, unsigned long arg)
1339 {
1340    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1341    if(pInfo==NULL)
1342       return -EINVAL;
1343    switch(cmd)
1344    {
1345       case R3964_ENABLE_SIGNALS:
1346          return enable_signals(pInfo, current->pid, arg);
1347       case R3964_SETPRIORITY:
1348          if(arg<R3964_MASTER || arg>R3964_SLAVE)
1349             return -EINVAL;
1350          pInfo->priority = arg & 0xff;
1351          return 0;
1352       case R3964_USE_BCC:
1353              if(arg)
1354             pInfo->flags |= R3964_BCC;
1355          else
1356             pInfo->flags &= ~R3964_BCC;
1357          return 0;
1358       case R3964_READ_TELEGRAM:
1359          return read_telegram(pInfo, current->pid, (unsigned char *)arg);
1360       default:
1361          return -ENOIOCTLCMD;
1362    }
1363 }
1364
1365 static void r3964_set_termios(struct tty_struct *tty, struct termios * old)
1366 {
1367    TRACE_L("set_termios");
1368 }
1369
1370 /* Called without the kernel lock held - fine */
1371 static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
1372                       struct poll_table_struct *wait)
1373 {
1374    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1375    int pid=current->pid;
1376    struct r3964_client_info *pClient;
1377    struct r3964_message *pMsg=NULL;
1378    unsigned long flags;
1379    int result = POLLOUT;
1380
1381    TRACE_L("POLL");
1382
1383    pClient=findClient(pInfo,pid);
1384    if(pClient)
1385      {
1386        poll_wait(file, &pInfo->read_wait, wait);
1387        spin_lock_irqsave(&pInfo->lock, flags);
1388        pMsg=pClient->first_msg;
1389        spin_unlock_irqrestore(&pInfo->lock, flags);
1390        if(pMsg)
1391            result |= POLLIN | POLLRDNORM;
1392      }
1393    else
1394      {
1395        result = -EINVAL;
1396      }
1397    return result;
1398 }
1399
1400 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1401                               char *fp, int count)
1402 {
1403    struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
1404     const unsigned char *p;
1405     char *f, flags = 0;
1406     int i;
1407
1408     for (i=count, p = cp, f = fp; i; i--, p++) {
1409         if (f)
1410             flags = *f++;
1411         if(flags==TTY_NORMAL)
1412         {
1413             receive_char(pInfo, *p);
1414         }
1415         else
1416         {
1417             receive_error(pInfo, flags);
1418         }
1419
1420     }
1421 }
1422
1423 static int r3964_receive_room(struct tty_struct *tty)
1424 {
1425    TRACE_L("receive_room");
1426    return -1;
1427 }
1428
1429
1430 MODULE_LICENSE("GPL");
1431