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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 /*#define DEBUG_QUEUE*/
  72
  73 /* Log successful handshake and protocol operations  */
  74 /*#define DEBUG_PROTO_S*/
  75
  76 /* Log handshake and protocol errors: */
  77 /*#define DEBUG_PROTO_E*/
  78
  79 /* Log Linediscipline operations (open, close, read, write...): */
  80 /*#define DEBUG_LDISC*/
  81
  82 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
  83 /*#define DEBUG_MODUL*/
  84
  85 /* Macro helpers for debug output: */
  86 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
  87
  88 #ifdef DEBUG_MODUL
  89 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
  90 #else
  91 #define TRACE_M(fmt, arg...) do {} while (0)
  92 #endif
  93 #ifdef DEBUG_PROTO_S
  94 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
  95 #else
  96 #define TRACE_PS(fmt, arg...) do {} while (0)
  97 #endif
  98 #ifdef DEBUG_PROTO_E
  99 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
 100 #else
 101 #define TRACE_PE(fmt, arg...) do {} while (0)
 102 #endif
 103 #ifdef DEBUG_LDISC
 104 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
 105 #else
 106 #define TRACE_L(fmt, arg...) do {} while (0)
 107 #endif
 108 #ifdef DEBUG_QUEUE
 109 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
 110 #else
 111 #define TRACE_Q(fmt, arg...) do {} while (0)
 112 #endif
 113 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
 114 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
 115 static void put_char(struct r3964_info *pInfo, unsigned char ch);
 116 static void trigger_transmit(struct r3964_info *pInfo);
 117 static void retry_transmit(struct r3964_info *pInfo);
 118 static void transmit_block(struct r3964_info *pInfo);
 119 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
 120 static void receive_error(struct r3964_info *pInfo, const char flag);
 121 static void on_timeout(unsigned long priv);
 122 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
 123 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 124                 unsigned char __user * buf);
 125 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 126                 int error_code, struct r3964_block_header *pBlock);
 127 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 128                 struct r3964_client_info *pClient);
 129 static void remove_client_block(struct r3964_info *pInfo,
 130                 struct r3964_client_info *pClient);
 131
 132 static int r3964_open(struct tty_struct *tty);
 133 static void r3964_close(struct tty_struct *tty);
 134 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
 135                 unsigned char __user * buf, size_t nr);
 136 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
 137                 const unsigned char *buf, size_t nr);
 138 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
 139                 unsigned int cmd, unsigned long arg);
 140 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
 141 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
 142                 struct poll_table_struct *wait);
 143 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 144                 char *fp, int count);
 145
 146 static struct tty_ldisc tty_ldisc_N_R3964 = {
 147         .owner = THIS_MODULE,
 148         .magic = TTY_LDISC_MAGIC,
 149         .name = "R3964",
 150         .open = r3964_open,
 151         .close = r3964_close,
 152         .read = r3964_read,
 153         .write = r3964_write,
 154         .ioctl = r3964_ioctl,
 155         .set_termios = r3964_set_termios,
 156         .poll = r3964_poll,
 157         .receive_buf = r3964_receive_buf,
 158 };
 159
 160 static void dump_block(const unsigned char *block, unsigned int length)
 161 {
 162         unsigned int i, j;
 163         char linebuf[16 * 3 + 1];
 164
 165         for (i = 0; i < length; i += 16) {
 166                 for (j = 0; (j < 16) && (j + i < length); j++) {
 167                         sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
 168                 }
 169                 linebuf[3 * j] = '\0';
 170                 TRACE_PS("%s", linebuf);
 171         }
 172 }
 173
 174 /*************************************************************
 175  * Driver initialisation
 176  *************************************************************/
 177
 178 /*************************************************************
 179  * Module support routines
 180  *************************************************************/
 181
 182 static void __exit r3964_exit(void)
 183 {
 184         int status;
 185
 186         TRACE_M("cleanup_module()");
 187
 188         status = tty_unregister_ldisc(N_R3964);
 189
 190         if (status != 0) {
 191                 printk(KERN_ERR "r3964: error unregistering linediscipline: "
 192                                 "%d\n", status);
 193         } else {
 194                 TRACE_L("linediscipline successfully unregistered");
 195         }
 196 }
 197
 198 static int __init r3964_init(void)
 199 {
 200         int status;
 201
 202         printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
 203
 204         /*
 205          * Register the tty line discipline
 206          */
 207
 208         status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
 209         if (status == 0) {
 210                 TRACE_L("line discipline %d registered", N_R3964);
 211                 TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 212                         tty_ldisc_N_R3964.num);
 213                 TRACE_L("open=%p", tty_ldisc_N_R3964.open);
 214                 TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
 215         } else {
 216                 printk(KERN_ERR "r3964: error registering line discipline: "
 217                                 "%d\n", status);
 218         }
 219         return status;
 220 }
 221
 222 module_init(r3964_init);
 223 module_exit(r3964_exit);
 224
 225 /*************************************************************
 226  * Protocol implementation routines
 227  *************************************************************/
 228
 229 static void add_tx_queue(struct r3964_info *pInfo,
 230                          struct r3964_block_header *pHeader)
 231 {
 232         unsigned long flags;
 233
 234         spin_lock_irqsave(&pInfo->lock, flags);
 235
 236         pHeader->next = NULL;
 237
 238         if (pInfo->tx_last == NULL) {
 239                 pInfo->tx_first = pInfo->tx_last = pHeader;
 240         } else {
 241                 pInfo->tx_last->next = pHeader;
 242                 pInfo->tx_last = pHeader;
 243         }
 244
 245         spin_unlock_irqrestore(&pInfo->lock, flags);
 246
 247         TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
 248                 pHeader, pHeader->length, pInfo->tx_first);
 249 }
 250
 251 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 252 {
 253         struct r3964_block_header *pHeader;
 254         unsigned long flags;
 255 #ifdef DEBUG_QUEUE
 256         struct r3964_block_header *pDump;
 257 #endif
 258
 259         pHeader = pInfo->tx_first;
 260
 261         if (pHeader == NULL)
 262                 return;
 263
 264 #ifdef DEBUG_QUEUE
 265         printk("r3964: remove_from_tx_queue: %p, length %u - ",
 266                 pHeader, pHeader->length);
 267         for (pDump = pHeader; pDump; pDump = pDump->next)
 268                 printk("%p ", pDump);
 269         printk("\n");
 270 #endif
 271
 272         if (pHeader->owner) {
 273                 if (error_code) {
 274                         add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 275                                 error_code, NULL);
 276                 } else {
 277                         add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 278                                 error_code, NULL);
 279                 }
 280                 wake_up_interruptible(&pInfo->read_wait);
 281         }
 282
 283         spin_lock_irqsave(&pInfo->lock, flags);
 284
 285         pInfo->tx_first = pHeader->next;
 286         if (pInfo->tx_first == NULL) {
 287                 pInfo->tx_last = NULL;
 288         }
 289
 290         spin_unlock_irqrestore(&pInfo->lock, flags);
 291
 292         kfree(pHeader);
 293         TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
 294
 295         TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
 296                 pInfo->tx_first, pInfo->tx_last);
 297 }
 298
 299 static void add_rx_queue(struct r3964_info *pInfo,
 300                          struct r3964_block_header *pHeader)
 301 {
 302         unsigned long flags;
 303
 304         spin_lock_irqsave(&pInfo->lock, flags);
 305
 306         pHeader->next = NULL;
 307
 308         if (pInfo->rx_last == NULL) {
 309                 pInfo->rx_first = pInfo->rx_last = pHeader;
 310         } else {
 311                 pInfo->rx_last->next = pHeader;
 312                 pInfo->rx_last = pHeader;
 313         }
 314         pInfo->blocks_in_rx_queue++;
 315
 316         spin_unlock_irqrestore(&pInfo->lock, flags);
 317
 318         TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
 319                 pHeader, pHeader->length,
 320                 pInfo->rx_first, pInfo->blocks_in_rx_queue);
 321 }
 322
 323 static void remove_from_rx_queue(struct r3964_info *pInfo,
 324                                  struct r3964_block_header *pHeader)
 325 {
 326         unsigned long flags;
 327         struct r3964_block_header *pFind;
 328
 329         if (pHeader == NULL)
 330                 return;
 331
 332         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 333                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 334         TRACE_Q("remove_from_rx_queue: %p, length %u",
 335                 pHeader, pHeader->length);
 336
 337         spin_lock_irqsave(&pInfo->lock, flags);
 338
 339         if (pInfo->rx_first == pHeader) {
 340                 /* Remove the first block in the linked list: */
 341                 pInfo->rx_first = pHeader->next;
 342
 343                 if (pInfo->rx_first == NULL) {
 344                         pInfo->rx_last = NULL;
 345                 }
 346                 pInfo->blocks_in_rx_queue--;
 347         } else {
 348                 /* Find block to remove: */
 349                 for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
 350                         if (pFind->next == pHeader) {
 351                                 /* Got it. */
 352                                 pFind->next = pHeader->next;
 353                                 pInfo->blocks_in_rx_queue--;
 354                                 if (pFind->next == NULL) {
 355                                         /* Oh, removed the last one! */
 356                                         pInfo->rx_last = pFind;
 357                                 }
 358                                 break;
 359                         }
 360                 }
 361         }
 362
 363         spin_unlock_irqrestore(&pInfo->lock, flags);
 364
 365         kfree(pHeader);
 366         TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
 367
 368         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 369                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 370 }
 371
 372 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 373 {
 374         struct tty_struct *tty = pInfo->tty;
 375
 376         if (tty == NULL)
 377                 return;
 378
 379         /* FIXME: put_char should not be called from an IRQ */
 380         if (tty->ops->put_char) {
 381                 tty->ops->put_char(tty, ch);
 382         }
 383         pInfo->bcc ^= ch;
 384 }
 385
 386 static void flush(struct r3964_info *pInfo)
 387 {
 388         struct tty_struct *tty = pInfo->tty;
 389
 390         if (tty == NULL || tty->ops->flush_chars == NULL)
 391                 return;
 392         tty->ops->flush_chars(tty);
 393 }
 394
 395 static void trigger_transmit(struct r3964_info *pInfo)
 396 {
 397         unsigned long flags;
 398
 399         spin_lock_irqsave(&pInfo->lock, flags);
 400
 401         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
 402                 pInfo->state = R3964_TX_REQUEST;
 403                 pInfo->nRetry = 0;
 404                 pInfo->flags &= ~R3964_ERROR;
 405                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 406
 407                 spin_unlock_irqrestore(&pInfo->lock, flags);
 408
 409                 TRACE_PS("trigger_transmit - sent STX");
 410
 411                 put_char(pInfo, STX);
 412                 flush(pInfo);
 413
 414                 pInfo->bcc = 0;
 415         } else {
 416                 spin_unlock_irqrestore(&pInfo->lock, flags);
 417         }
 418 }
 419
 420 static void retry_transmit(struct r3964_info *pInfo)
 421 {
 422         if (pInfo->nRetry < R3964_MAX_RETRIES) {
 423                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
 424                 pInfo->bcc = 0;
 425                 put_char(pInfo, STX);
 426                 flush(pInfo);
 427                 pInfo->state = R3964_TX_REQUEST;
 428                 pInfo->nRetry++;
 429                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 430         } else {
 431                 TRACE_PE("transmission failed after %d retries",
 432                          R3964_MAX_RETRIES);
 433
 434                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 435
 436                 put_char(pInfo, NAK);
 437                 flush(pInfo);
 438                 pInfo->state = R3964_IDLE;
 439
 440                 trigger_transmit(pInfo);
 441         }
 442 }
 443
 444 static void transmit_block(struct r3964_info *pInfo)
 445 {
 446         struct tty_struct *tty = pInfo->tty;
 447         struct r3964_block_header *pBlock = pInfo->tx_first;
 448         int room = 0;
 449
 450         if (tty == NULL || pBlock == NULL) {
 451                 return;
 452         }
 453
 454         room = tty_write_room(tty);
 455
 456         TRACE_PS("transmit_block %p, room %d, length %d",
 457                  pBlock, room, pBlock->length);
 458
 459         while (pInfo->tx_position < pBlock->length) {
 460                 if (room < 2)
 461                         break;
 462
 463                 if (pBlock->data[pInfo->tx_position] == DLE) {
 464                         /* send additional DLE char: */
 465                         put_char(pInfo, DLE);
 466                 }
 467                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 468
 469                 room--;
 470         }
 471
 472         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
 473                 put_char(pInfo, DLE);
 474                 put_char(pInfo, ETX);
 475                 if (pInfo->flags & R3964_BCC) {
 476                         put_char(pInfo, pInfo->bcc);
 477                 }
 478                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
 479                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 480         }
 481         flush(pInfo);
 482 }
 483
 484 static void on_receive_block(struct r3964_info *pInfo)
 485 {
 486         unsigned int length;
 487         struct r3964_client_info *pClient;
 488         struct r3964_block_header *pBlock;
 489
 490         length = pInfo->rx_position;
 491
 492         /* compare byte checksum characters: */
 493         if (pInfo->flags & R3964_BCC) {
 494                 if (pInfo->bcc != pInfo->last_rx) {
 495                         TRACE_PE("checksum error - got %x but expected %x",
 496                                  pInfo->last_rx, pInfo->bcc);
 497                         pInfo->flags |= R3964_CHECKSUM;
 498                 }
 499         }
 500
 501         /* check for errors (parity, overrun,...): */
 502         if (pInfo->flags & R3964_ERROR) {
 503                 TRACE_PE("on_receive_block - transmission failed error %x",
 504                          pInfo->flags & R3964_ERROR);
 505
 506                 put_char(pInfo, NAK);
 507                 flush(pInfo);
 508                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
 509                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
 510                         pInfo->nRetry++;
 511                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 512                 } else {
 513                         TRACE_PE("on_receive_block - failed after max retries");
 514                         pInfo->state = R3964_IDLE;
 515                 }
 516                 return;
 517         }
 518
 519         /* received block; submit DLE: */
 520         put_char(pInfo, DLE);
 521         flush(pInfo);
 522         del_timer_sync(&pInfo->tmr);
 523         TRACE_PS(" rx success: got %d chars", length);
 524
 525         /* prepare struct r3964_block_header: */
 526         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
 527                         GFP_KERNEL);
 528         TRACE_M("on_receive_block - kmalloc %p", pBlock);
 529
 530         if (pBlock == NULL)
 531                 return;
 532
 533         pBlock->length = length;
 534         pBlock->data = ((unsigned char *)pBlock) +
 535                         sizeof(struct r3964_block_header);
 536         pBlock->locks = 0;
 537         pBlock->next = NULL;
 538         pBlock->owner = NULL;
 539
 540         memcpy(pBlock->data, pInfo->rx_buf, length);
 541
 542         /* queue block into rx_queue: */
 543         add_rx_queue(pInfo, pBlock);
 544
 545         /* notify attached client processes: */
 546         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 547                 if (pClient->sig_flags & R3964_SIG_DATA) {
 548                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
 549                                 pBlock);
 550                 }
 551         }
 552         wake_up_interruptible(&pInfo->read_wait);
 553
 554         pInfo->state = R3964_IDLE;
 555
 556         trigger_transmit(pInfo);
 557 }
 558
 559 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 560 {
 561         switch (pInfo->state) {
 562         case R3964_TX_REQUEST:
 563                 if (c == DLE) {
 564                         TRACE_PS("TX_REQUEST - got DLE");
 565
 566                         pInfo->state = R3964_TRANSMITTING;
 567                         pInfo->tx_position = 0;
 568
 569                         transmit_block(pInfo);
 570                 } else if (c == STX) {
 571                         if (pInfo->nRetry == 0) {
 572                                 TRACE_PE("TX_REQUEST - init conflict");
 573                                 if (pInfo->priority == R3964_SLAVE) {
 574                                         goto start_receiving;
 575                                 }
 576                         } else {
 577                                 TRACE_PE("TX_REQUEST - secondary init "
 578                                         "conflict!? Switching to SLAVE mode "
 579                                         "for next rx.");
 580                                 goto start_receiving;
 581                         }
 582                 } else {
 583                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 584                         retry_transmit(pInfo);
 585                 }
 586                 break;
 587         case R3964_TRANSMITTING:
 588                 if (c == NAK) {
 589                         TRACE_PE("TRANSMITTING - got NAK");
 590                         retry_transmit(pInfo);
 591                 } else {
 592                         TRACE_PE("TRANSMITTING - got invalid char");
 593
 594                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 595                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 596                 }
 597                 break;
 598         case R3964_WAIT_FOR_TX_ACK:
 599                 if (c == DLE) {
 600                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 601                         remove_from_tx_queue(pInfo, R3964_OK);
 602
 603                         pInfo->state = R3964_IDLE;
 604                         trigger_transmit(pInfo);
 605                 } else {
 606                         retry_transmit(pInfo);
 607                 }
 608                 break;
 609         case R3964_WAIT_FOR_RX_REPEAT:
 610                 /* FALLTROUGH */
 611         case R3964_IDLE:
 612                 if (c == STX) {
 613                         /* Prevent rx_queue from overflow: */
 614                         if (pInfo->blocks_in_rx_queue >=
 615                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
 616                                 TRACE_PE("IDLE - got STX but no space in "
 617                                                 "rx_queue!");
 618                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
 619                                 mod_timer(&pInfo->tmr,
 620                                           jiffies + R3964_TO_NO_BUF);
 621                                 break;
 622                         }
 623 start_receiving:
 624                         /* Ok, start receiving: */
 625                         TRACE_PS("IDLE - got STX");
 626                         pInfo->rx_position = 0;
 627                         pInfo->last_rx = 0;
 628                         pInfo->flags &= ~R3964_ERROR;
 629                         pInfo->state = R3964_RECEIVING;
 630                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 631                         pInfo->nRetry = 0;
 632                         put_char(pInfo, DLE);
 633                         flush(pInfo);
 634                         pInfo->bcc = 0;
 635                 }
 636                 break;
 637         case R3964_RECEIVING:
 638                 if (pInfo->rx_position < RX_BUF_SIZE) {
 639                         pInfo->bcc ^= c;
 640
 641                         if (c == DLE) {
 642                                 if (pInfo->last_rx == DLE) {
 643                                         pInfo->last_rx = 0;
 644                                         goto char_to_buf;
 645                                 }
 646                                 pInfo->last_rx = DLE;
 647                                 break;
 648                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
 649                                 if (pInfo->flags & R3964_BCC) {
 650                                         pInfo->state = R3964_WAIT_FOR_BCC;
 651                                         mod_timer(&pInfo->tmr,
 652                                                   jiffies + R3964_TO_ZVZ);
 653                                 } else {
 654                                         on_receive_block(pInfo);
 655                                 }
 656                         } else {
 657                                 pInfo->last_rx = c;
 658 char_to_buf:
 659                                 pInfo->rx_buf[pInfo->rx_position++] = c;
 660                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 661                         }
 662                 }
 663                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 664                 break;
 665         case R3964_WAIT_FOR_BCC:
 666                 pInfo->last_rx = c;
 667                 on_receive_block(pInfo);
 668                 break;
 669         }
 670 }
 671
 672 static void receive_error(struct r3964_info *pInfo, const char flag)
 673 {
 674         switch (flag) {
 675         case TTY_NORMAL:
 676                 break;
 677         case TTY_BREAK:
 678                 TRACE_PE("received break");
 679                 pInfo->flags |= R3964_BREAK;
 680                 break;
 681         case TTY_PARITY:
 682                 TRACE_PE("parity error");
 683                 pInfo->flags |= R3964_PARITY;
 684                 break;
 685         case TTY_FRAME:
 686                 TRACE_PE("frame error");
 687                 pInfo->flags |= R3964_FRAME;
 688                 break;
 689         case TTY_OVERRUN:
 690                 TRACE_PE("frame overrun");
 691                 pInfo->flags |= R3964_OVERRUN;
 692                 break;
 693         default:
 694                 TRACE_PE("receive_error - unknown flag %d", flag);
 695                 pInfo->flags |= R3964_UNKNOWN;
 696                 break;
 697         }
 698 }
 699
 700 static void on_timeout(unsigned long priv)
 701 {
 702         struct r3964_info *pInfo = (void *)priv;
 703
 704         switch (pInfo->state) {
 705         case R3964_TX_REQUEST:
 706                 TRACE_PE("TX_REQUEST - timeout");
 707                 retry_transmit(pInfo);
 708                 break;
 709         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 710                 put_char(pInfo, NAK);
 711                 flush(pInfo);
 712                 retry_transmit(pInfo);
 713                 break;
 714         case R3964_WAIT_FOR_TX_ACK:
 715                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 716                 retry_transmit(pInfo);
 717                 break;
 718         case R3964_WAIT_FOR_RX_BUF:
 719                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 720                 put_char(pInfo, NAK);
 721                 flush(pInfo);
 722                 pInfo->state = R3964_IDLE;
 723                 break;
 724         case R3964_RECEIVING:
 725                 TRACE_PE("RECEIVING - timeout after %d chars",
 726                          pInfo->rx_position);
 727                 put_char(pInfo, NAK);
 728                 flush(pInfo);
 729                 pInfo->state = R3964_IDLE;
 730                 break;
 731         case R3964_WAIT_FOR_RX_REPEAT:
 732                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 733                 pInfo->state = R3964_IDLE;
 734                 break;
 735         case R3964_WAIT_FOR_BCC:
 736                 TRACE_PE("WAIT_FOR_BCC - timeout");
 737                 put_char(pInfo, NAK);
 738                 flush(pInfo);
 739                 pInfo->state = R3964_IDLE;
 740                 break;
 741         }
 742 }
 743
 744 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
 745                 struct pid *pid)
 746 {
 747         struct r3964_client_info *pClient;
 748
 749         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 750                 if (pClient->pid == pid) {
 751                         return pClient;
 752                 }
 753         }
 754         return NULL;
 755 }
 756
 757 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
 758 {
 759         struct r3964_client_info *pClient;
 760         struct r3964_client_info **ppClient;
 761         struct r3964_message *pMsg;
 762
 763         if ((arg & R3964_SIG_ALL) == 0) {
 764                 /* Remove client from client list */
 765                 for (ppClient = &pInfo->firstClient; *ppClient;
 766                      ppClient = &(*ppClient)->next) {
 767                         pClient = *ppClient;
 768
 769                         if (pClient->pid == pid) {
 770                                 TRACE_PS("removing client %d from client list",
 771                                          pid_nr(pid));
 772                                 *ppClient = pClient->next;
 773                                 while (pClient->msg_count) {
 774                                         pMsg = remove_msg(pInfo, pClient);
 775                                         if (pMsg) {
 776                                                 kfree(pMsg);
 777                                                 TRACE_M("enable_signals - msg "
 778                                                         "kfree %p", pMsg);
 779                                         }
 780                                 }
 781                                 put_pid(pClient->pid);
 782                                 kfree(pClient);
 783                                 TRACE_M("enable_signals - kfree %p", pClient);
 784                                 return 0;
 785                         }
 786                 }
 787                 return -EINVAL;
 788         } else {
 789                 pClient = findClient(pInfo, pid);
 790                 if (pClient) {
 791                         /* update signal options */
 792                         pClient->sig_flags = arg;
 793                 } else {
 794                         /* add client to client list */
 795                         pClient = kmalloc(sizeof(struct r3964_client_info),
 796                                         GFP_KERNEL);
 797                         TRACE_M("enable_signals - kmalloc %p", pClient);
 798                         if (pClient == NULL)
 799                                 return -ENOMEM;
 800
 801                         TRACE_PS("add client %d to client list", pid_nr(pid));
 802                         spin_lock_init(&pClient->lock);
 803                         pClient->sig_flags = arg;
 804                         pClient->pid = get_pid(pid);
 805                         pClient->next = pInfo->firstClient;
 806                         pClient->first_msg = NULL;
 807                         pClient->last_msg = NULL;
 808                         pClient->next_block_to_read = NULL;
 809                         pClient->msg_count = 0;
 810                         pInfo->firstClient = pClient;
 811                 }
 812         }
 813
 814         return 0;
 815 }
 816
 817 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 818                          unsigned char __user * buf)
 819 {
 820         struct r3964_client_info *pClient;
 821         struct r3964_block_header *block;
 822
 823         if (!buf) {
 824                 return -EINVAL;
 825         }
 826
 827         pClient = findClient(pInfo, pid);
 828         if (pClient == NULL) {
 829                 return -EINVAL;
 830         }
 831
 832         block = pClient->next_block_to_read;
 833         if (!block) {
 834                 return 0;
 835         } else {
 836                 if (copy_to_user(buf, block->data, block->length))
 837                         return -EFAULT;
 838
 839                 remove_client_block(pInfo, pClient);
 840                 return block->length;
 841         }
 842
 843         return -EINVAL;
 844 }
 845
 846 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 847                 int error_code, struct r3964_block_header *pBlock)
 848 {
 849         struct r3964_message *pMsg;
 850         unsigned long flags;
 851
 852         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
 853 queue_the_message:
 854
 855                 pMsg = kmalloc(sizeof(struct r3964_message),
 856                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
 857                 TRACE_M("add_msg - kmalloc %p", pMsg);
 858                 if (pMsg == NULL) {
 859                         return;
 860                 }
 861
 862                 spin_lock_irqsave(&pClient->lock, flags);
 863
 864                 pMsg->msg_id = msg_id;
 865                 pMsg->arg = arg;
 866                 pMsg->error_code = error_code;
 867                 pMsg->block = pBlock;
 868                 pMsg->next = NULL;
 869
 870                 if (pClient->last_msg == NULL) {
 871                         pClient->first_msg = pClient->last_msg = pMsg;
 872                 } else {
 873                         pClient->last_msg->next = pMsg;
 874                         pClient->last_msg = pMsg;
 875                 }
 876
 877                 pClient->msg_count++;
 878
 879                 if (pBlock != NULL) {
 880                         pBlock->locks++;
 881                 }
 882                 spin_unlock_irqrestore(&pClient->lock, flags);
 883         } else {
 884                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
 885                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
 886                         pClient->last_msg->arg++;
 887                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 888                 } else {
 889                         msg_id = R3964_MSG_ACK;
 890                         arg = 0;
 891                         error_code = R3964_OVERFLOW;
 892                         pBlock = NULL;
 893                         TRACE_PE("add_msg - queue OVERFLOW-msg");
 894                         goto queue_the_message;
 895                 }
 896         }
 897         /* Send SIGIO signal to client process: */
 898         if (pClient->sig_flags & R3964_USE_SIGIO) {
 899                 kill_pid(pClient->pid, SIGIO, 1);
 900         }
 901 }
 902
 903 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 904                                         struct r3964_client_info *pClient)
 905 {
 906         struct r3964_message *pMsg = NULL;
 907         unsigned long flags;
 908
 909         if (pClient->first_msg) {
 910                 spin_lock_irqsave(&pClient->lock, flags);
 911
 912                 pMsg = pClient->first_msg;
 913                 pClient->first_msg = pMsg->next;
 914                 if (pClient->first_msg == NULL) {
 915                         pClient->last_msg = NULL;
 916                 }
 917
 918                 pClient->msg_count--;
 919                 if (pMsg->block) {
 920                         remove_client_block(pInfo, pClient);
 921                         pClient->next_block_to_read = pMsg->block;
 922                 }
 923                 spin_unlock_irqrestore(&pClient->lock, flags);
 924         }
 925         return pMsg;
 926 }
 927
 928 static void remove_client_block(struct r3964_info *pInfo,
 929                                 struct r3964_client_info *pClient)
 930 {
 931         struct r3964_block_header *block;
 932
 933         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
 934
 935         block = pClient->next_block_to_read;
 936         if (block) {
 937                 block->locks--;
 938                 if (block->locks == 0) {
 939                         remove_from_rx_queue(pInfo, block);
 940                 }
 941         }
 942         pClient->next_block_to_read = NULL;
 943 }
 944
 945 /*************************************************************
 946  * Line discipline routines
 947  *************************************************************/
 948
 949 static int r3964_open(struct tty_struct *tty)
 950 {
 951         struct r3964_info *pInfo;
 952
 953         TRACE_L("open");
 954         TRACE_L("tty=%p, PID=%d, disc_data=%p",
 955                 tty, current->pid, tty->disc_data);
 956
 957         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
 958         TRACE_M("r3964_open - info kmalloc %p", pInfo);
 959
 960         if (!pInfo) {
 961                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
 962                 return -ENOMEM;
 963         }
 964
 965         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
 966         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
 967
 968         if (!pInfo->rx_buf) {
 969                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
 970                 kfree(pInfo);
 971                 TRACE_M("r3964_open - info kfree %p", pInfo);
 972                 return -ENOMEM;
 973         }
 974
 975         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
 976         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
 977
 978         if (!pInfo->tx_buf) {
 979                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
 980                 kfree(pInfo->rx_buf);
 981                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
 982                 kfree(pInfo);
 983                 TRACE_M("r3964_open - info kfree %p", pInfo);
 984                 return -ENOMEM;
 985         }
 986
 987         spin_lock_init(&pInfo->lock);
 988         pInfo->tty = tty;
 989         init_waitqueue_head(&pInfo->read_wait);
 990         pInfo->priority = R3964_MASTER;
 991         pInfo->rx_first = pInfo->rx_last = NULL;
 992         pInfo->tx_first = pInfo->tx_last = NULL;
 993         pInfo->rx_position = 0;
 994         pInfo->tx_position = 0;
 995         pInfo->last_rx = 0;
 996         pInfo->blocks_in_rx_queue = 0;
 997         pInfo->firstClient = NULL;
 998         pInfo->state = R3964_IDLE;
 999         pInfo->flags = R3964_DEBUG;
1000         pInfo->nRetry = 0;
1001
1002         tty->disc_data = pInfo;
1003         tty->receive_room = 65536;
1004
1005         setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
1006
1007         return 0;
1008 }
1009
1010 static void r3964_close(struct tty_struct *tty)
1011 {
1012         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1013         struct r3964_client_info *pClient, *pNext;
1014         struct r3964_message *pMsg;
1015         struct r3964_block_header *pHeader, *pNextHeader;
1016         unsigned long flags;
1017
1018         TRACE_L("close");
1019
1020         /*
1021          * Make sure that our task queue isn't activated.  If it
1022          * is, take it out of the linked list.
1023          */
1024         del_timer_sync(&pInfo->tmr);
1025
1026         /* Remove client-structs and message queues: */
1027         pClient = pInfo->firstClient;
1028         while (pClient) {
1029                 pNext = pClient->next;
1030                 while (pClient->msg_count) {
1031                         pMsg = remove_msg(pInfo, pClient);
1032                         if (pMsg) {
1033                                 kfree(pMsg);
1034                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1035                         }
1036                 }
1037                 put_pid(pClient->pid);
1038                 kfree(pClient);
1039                 TRACE_M("r3964_close - client kfree %p", pClient);
1040                 pClient = pNext;
1041         }
1042         /* Remove jobs from tx_queue: */
1043         spin_lock_irqsave(&pInfo->lock, flags);
1044         pHeader = pInfo->tx_first;
1045         pInfo->tx_first = pInfo->tx_last = NULL;
1046         spin_unlock_irqrestore(&pInfo->lock, flags);
1047
1048         while (pHeader) {
1049                 pNextHeader = pHeader->next;
1050                 kfree(pHeader);
1051                 pHeader = pNextHeader;
1052         }
1053
1054         /* Free buffers: */
1055         wake_up_interruptible(&pInfo->read_wait);
1056         kfree(pInfo->rx_buf);
1057         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1058         kfree(pInfo->tx_buf);
1059         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1060         kfree(pInfo);
1061         TRACE_M("r3964_close - info kfree %p", pInfo);
1062 }
1063
1064 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1065                           unsigned char __user * buf, size_t nr)
1066 {
1067         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1068         struct r3964_client_info *pClient;
1069         struct r3964_message *pMsg;
1070         struct r3964_client_message theMsg;
1071         int count;
1072
1073         TRACE_L("read()");
1074
1075         lock_kernel();
1076
1077         pClient = findClient(pInfo, task_pid(current));
1078         if (pClient) {
1079                 pMsg = remove_msg(pInfo, pClient);
1080                 if (pMsg == NULL) {
1081                         /* no messages available. */
1082                         if (file->f_flags & O_NONBLOCK) {
1083                                 unlock_kernel();
1084                                 return -EAGAIN;
1085                         }
1086                         /* block until there is a message: */
1087                         wait_event_interruptible(pInfo->read_wait,
1088                                         (pMsg = remove_msg(pInfo, pClient)));
1089                 }
1090
1091                 /* If we still haven't got a message, we must have been signalled */
1092
1093                 if (!pMsg) {
1094                         unlock_kernel();
1095                         return -EINTR;
1096                 }
1097
1098                 /* deliver msg to client process: */
1099                 theMsg.msg_id = pMsg->msg_id;
1100                 theMsg.arg = pMsg->arg;
1101                 theMsg.error_code = pMsg->error_code;
1102                 count = sizeof(struct r3964_client_message);
1103
1104                 kfree(pMsg);
1105                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1106
1107                 if (copy_to_user(buf, &theMsg, count)) {
1108                         unlock_kernel();
1109                         return -EFAULT;
1110                 }
1111
1112                 TRACE_PS("read - return %d", count);
1113                 return count;
1114         }
1115         unlock_kernel();
1116         return -EPERM;
1117 }
1118
1119 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1120                            const unsigned char *data, size_t count)
1121 {
1122         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1123         struct r3964_block_header *pHeader;
1124         struct r3964_client_info *pClient;
1125         unsigned char *new_data;
1126
1127         TRACE_L("write request, %d characters", count);
1128 /*
1129  * Verify the pointers
1130  */
1131
1132         if (!pInfo)
1133                 return -EIO;
1134
1135 /*
1136  * Ensure that the caller does not wish to send too much.
1137  */
1138         if (count > R3964_MTU) {
1139                 if (pInfo->flags & R3964_DEBUG) {
1140                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1141                                 "packet from %u to mtu %d", count, R3964_MTU);
1142                 }
1143                 count = R3964_MTU;
1144         }
1145 /*
1146  * Allocate a buffer for the data and copy it from the buffer with header prepended
1147  */
1148         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1149                         GFP_KERNEL);
1150         TRACE_M("r3964_write - kmalloc %p", new_data);
1151         if (new_data == NULL) {
1152                 if (pInfo->flags & R3964_DEBUG) {
1153                         printk(KERN_ERR "r3964_write: no memory\n");
1154                 }
1155                 return -ENOSPC;
1156         }
1157
1158         pHeader = (struct r3964_block_header *)new_data;
1159         pHeader->data = new_data + sizeof(struct r3964_block_header);
1160         pHeader->length = count;
1161         pHeader->locks = 0;
1162         pHeader->owner = NULL;
1163
1164         lock_kernel();
1165
1166         pClient = findClient(pInfo, task_pid(current));
1167         if (pClient) {
1168                 pHeader->owner = pClient;
1169         }
1170
1171         memcpy(pHeader->data, data, count);     /* We already verified this */
1172
1173         if (pInfo->flags & R3964_DEBUG) {
1174                 dump_block(pHeader->data, count);
1175         }
1176
1177 /*
1178  * Add buffer to transmit-queue:
1179  */
1180         add_tx_queue(pInfo, pHeader);
1181         trigger_transmit(pInfo);
1182
1183         unlock_kernel();
1184
1185         return 0;
1186 }
1187
1188 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1189                 unsigned int cmd, unsigned long arg)
1190 {
1191         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1192         if (pInfo == NULL)
1193                 return -EINVAL;
1194         switch (cmd) {
1195         case R3964_ENABLE_SIGNALS:
1196                 return enable_signals(pInfo, task_pid(current), arg);
1197         case R3964_SETPRIORITY:
1198                 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1199                         return -EINVAL;
1200                 pInfo->priority = arg & 0xff;
1201                 return 0;
1202         case R3964_USE_BCC:
1203                 if (arg)
1204                         pInfo->flags |= R3964_BCC;
1205                 else
1206                         pInfo->flags &= ~R3964_BCC;
1207                 return 0;
1208         case R3964_READ_TELEGRAM:
1209                 return read_telegram(pInfo, task_pid(current),
1210                                 (unsigned char __user *)arg);
1211         default:
1212                 return -ENOIOCTLCMD;
1213         }
1214 }
1215
1216 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1217 {
1218         TRACE_L("set_termios");
1219 }
1220
1221 /* Called without the kernel lock held - fine */
1222 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1223                         struct poll_table_struct *wait)
1224 {
1225         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1226         struct r3964_client_info *pClient;
1227         struct r3964_message *pMsg = NULL;
1228         unsigned long flags;
1229         int result = POLLOUT;
1230
1231         TRACE_L("POLL");
1232
1233         pClient = findClient(pInfo, task_pid(current));
1234         if (pClient) {
1235                 poll_wait(file, &pInfo->read_wait, wait);
1236                 spin_lock_irqsave(&pInfo->lock, flags);
1237                 pMsg = pClient->first_msg;
1238                 spin_unlock_irqrestore(&pInfo->lock, flags);
1239                 if (pMsg)
1240                         result |= POLLIN | POLLRDNORM;
1241         } else {
1242                 result = -EINVAL;
1243         }
1244         return result;
1245 }
1246
1247 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1248                         char *fp, int count)
1249 {
1250         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1251         const unsigned char *p;
1252         char *f, flags = 0;
1253         int i;
1254
1255         for (i = count, p = cp, f = fp; i; i--, p++) {
1256                 if (f)
1257                         flags = *f++;
1258                 if (flags == TTY_NORMAL) {
1259                         receive_char(pInfo, *p);
1260                 } else {
1261                         receive_error(pInfo, flags);
1262                 }
1263
1264         }
1265 }
1266
1267 MODULE_LICENSE("GPL");
1268 MODULE_ALIAS_LDISC(N_R3964);