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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_ops 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         /* FIXME: put_char should not be called from an IRQ */
 376         tty_put_char(tty, ch);
 377         pInfo->bcc ^= ch;
 378 }
 379
 380 static void flush(struct r3964_info *pInfo)
 381 {
 382         struct tty_struct *tty = pInfo->tty;
 383
 384         if (tty == NULL || tty->ops->flush_chars == NULL)
 385                 return;
 386         tty->ops->flush_chars(tty);
 387 }
 388
 389 static void trigger_transmit(struct r3964_info *pInfo)
 390 {
 391         unsigned long flags;
 392
 393         spin_lock_irqsave(&pInfo->lock, flags);
 394
 395         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
 396                 pInfo->state = R3964_TX_REQUEST;
 397                 pInfo->nRetry = 0;
 398                 pInfo->flags &= ~R3964_ERROR;
 399                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 400
 401                 spin_unlock_irqrestore(&pInfo->lock, flags);
 402
 403                 TRACE_PS("trigger_transmit - sent STX");
 404
 405                 put_char(pInfo, STX);
 406                 flush(pInfo);
 407
 408                 pInfo->bcc = 0;
 409         } else {
 410                 spin_unlock_irqrestore(&pInfo->lock, flags);
 411         }
 412 }
 413
 414 static void retry_transmit(struct r3964_info *pInfo)
 415 {
 416         if (pInfo->nRetry < R3964_MAX_RETRIES) {
 417                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
 418                 pInfo->bcc = 0;
 419                 put_char(pInfo, STX);
 420                 flush(pInfo);
 421                 pInfo->state = R3964_TX_REQUEST;
 422                 pInfo->nRetry++;
 423                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 424         } else {
 425                 TRACE_PE("transmission failed after %d retries",
 426                          R3964_MAX_RETRIES);
 427
 428                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 429
 430                 put_char(pInfo, NAK);
 431                 flush(pInfo);
 432                 pInfo->state = R3964_IDLE;
 433
 434                 trigger_transmit(pInfo);
 435         }
 436 }
 437
 438 static void transmit_block(struct r3964_info *pInfo)
 439 {
 440         struct tty_struct *tty = pInfo->tty;
 441         struct r3964_block_header *pBlock = pInfo->tx_first;
 442         int room = 0;
 443
 444         if (tty == NULL || pBlock == NULL) {
 445                 return;
 446         }
 447
 448         room = tty_write_room(tty);
 449
 450         TRACE_PS("transmit_block %p, room %d, length %d",
 451                  pBlock, room, pBlock->length);
 452
 453         while (pInfo->tx_position < pBlock->length) {
 454                 if (room < 2)
 455                         break;
 456
 457                 if (pBlock->data[pInfo->tx_position] == DLE) {
 458                         /* send additional DLE char: */
 459                         put_char(pInfo, DLE);
 460                 }
 461                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 462
 463                 room--;
 464         }
 465
 466         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
 467                 put_char(pInfo, DLE);
 468                 put_char(pInfo, ETX);
 469                 if (pInfo->flags & R3964_BCC) {
 470                         put_char(pInfo, pInfo->bcc);
 471                 }
 472                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
 473                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 474         }
 475         flush(pInfo);
 476 }
 477
 478 static void on_receive_block(struct r3964_info *pInfo)
 479 {
 480         unsigned int length;
 481         struct r3964_client_info *pClient;
 482         struct r3964_block_header *pBlock;
 483
 484         length = pInfo->rx_position;
 485
 486         /* compare byte checksum characters: */
 487         if (pInfo->flags & R3964_BCC) {
 488                 if (pInfo->bcc != pInfo->last_rx) {
 489                         TRACE_PE("checksum error - got %x but expected %x",
 490                                  pInfo->last_rx, pInfo->bcc);
 491                         pInfo->flags |= R3964_CHECKSUM;
 492                 }
 493         }
 494
 495         /* check for errors (parity, overrun,...): */
 496         if (pInfo->flags & R3964_ERROR) {
 497                 TRACE_PE("on_receive_block - transmission failed error %x",
 498                          pInfo->flags & R3964_ERROR);
 499
 500                 put_char(pInfo, NAK);
 501                 flush(pInfo);
 502                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
 503                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
 504                         pInfo->nRetry++;
 505                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 506                 } else {
 507                         TRACE_PE("on_receive_block - failed after max retries");
 508                         pInfo->state = R3964_IDLE;
 509                 }
 510                 return;
 511         }
 512
 513         /* received block; submit DLE: */
 514         put_char(pInfo, DLE);
 515         flush(pInfo);
 516         del_timer_sync(&pInfo->tmr);
 517         TRACE_PS(" rx success: got %d chars", length);
 518
 519         /* prepare struct r3964_block_header: */
 520         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
 521                         GFP_KERNEL);
 522         TRACE_M("on_receive_block - kmalloc %p", pBlock);
 523
 524         if (pBlock == NULL)
 525                 return;
 526
 527         pBlock->length = length;
 528         pBlock->data = ((unsigned char *)pBlock) +
 529                         sizeof(struct r3964_block_header);
 530         pBlock->locks = 0;
 531         pBlock->next = NULL;
 532         pBlock->owner = NULL;
 533
 534         memcpy(pBlock->data, pInfo->rx_buf, length);
 535
 536         /* queue block into rx_queue: */
 537         add_rx_queue(pInfo, pBlock);
 538
 539         /* notify attached client processes: */
 540         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 541                 if (pClient->sig_flags & R3964_SIG_DATA) {
 542                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
 543                                 pBlock);
 544                 }
 545         }
 546         wake_up_interruptible(&pInfo->read_wait);
 547
 548         pInfo->state = R3964_IDLE;
 549
 550         trigger_transmit(pInfo);
 551 }
 552
 553 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 554 {
 555         switch (pInfo->state) {
 556         case R3964_TX_REQUEST:
 557                 if (c == DLE) {
 558                         TRACE_PS("TX_REQUEST - got DLE");
 559
 560                         pInfo->state = R3964_TRANSMITTING;
 561                         pInfo->tx_position = 0;
 562
 563                         transmit_block(pInfo);
 564                 } else if (c == STX) {
 565                         if (pInfo->nRetry == 0) {
 566                                 TRACE_PE("TX_REQUEST - init conflict");
 567                                 if (pInfo->priority == R3964_SLAVE) {
 568                                         goto start_receiving;
 569                                 }
 570                         } else {
 571                                 TRACE_PE("TX_REQUEST - secondary init "
 572                                         "conflict!? Switching to SLAVE mode "
 573                                         "for next rx.");
 574                                 goto start_receiving;
 575                         }
 576                 } else {
 577                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 578                         retry_transmit(pInfo);
 579                 }
 580                 break;
 581         case R3964_TRANSMITTING:
 582                 if (c == NAK) {
 583                         TRACE_PE("TRANSMITTING - got NAK");
 584                         retry_transmit(pInfo);
 585                 } else {
 586                         TRACE_PE("TRANSMITTING - got invalid char");
 587
 588                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 589                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 590                 }
 591                 break;
 592         case R3964_WAIT_FOR_TX_ACK:
 593                 if (c == DLE) {
 594                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 595                         remove_from_tx_queue(pInfo, R3964_OK);
 596
 597                         pInfo->state = R3964_IDLE;
 598                         trigger_transmit(pInfo);
 599                 } else {
 600                         retry_transmit(pInfo);
 601                 }
 602                 break;
 603         case R3964_WAIT_FOR_RX_REPEAT:
 604                 /* FALLTROUGH */
 605         case R3964_IDLE:
 606                 if (c == STX) {
 607                         /* Prevent rx_queue from overflow: */
 608                         if (pInfo->blocks_in_rx_queue >=
 609                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
 610                                 TRACE_PE("IDLE - got STX but no space in "
 611                                                 "rx_queue!");
 612                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
 613                                 mod_timer(&pInfo->tmr,
 614                                           jiffies + R3964_TO_NO_BUF);
 615                                 break;
 616                         }
 617 start_receiving:
 618                         /* Ok, start receiving: */
 619                         TRACE_PS("IDLE - got STX");
 620                         pInfo->rx_position = 0;
 621                         pInfo->last_rx = 0;
 622                         pInfo->flags &= ~R3964_ERROR;
 623                         pInfo->state = R3964_RECEIVING;
 624                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 625                         pInfo->nRetry = 0;
 626                         put_char(pInfo, DLE);
 627                         flush(pInfo);
 628                         pInfo->bcc = 0;
 629                 }
 630                 break;
 631         case R3964_RECEIVING:
 632                 if (pInfo->rx_position < RX_BUF_SIZE) {
 633                         pInfo->bcc ^= c;
 634
 635                         if (c == DLE) {
 636                                 if (pInfo->last_rx == DLE) {
 637                                         pInfo->last_rx = 0;
 638                                         goto char_to_buf;
 639                                 }
 640                                 pInfo->last_rx = DLE;
 641                                 break;
 642                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
 643                                 if (pInfo->flags & R3964_BCC) {
 644                                         pInfo->state = R3964_WAIT_FOR_BCC;
 645                                         mod_timer(&pInfo->tmr,
 646                                                   jiffies + R3964_TO_ZVZ);
 647                                 } else {
 648                                         on_receive_block(pInfo);
 649                                 }
 650                         } else {
 651                                 pInfo->last_rx = c;
 652 char_to_buf:
 653                                 pInfo->rx_buf[pInfo->rx_position++] = c;
 654                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 655                         }
 656                 }
 657                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 658                 break;
 659         case R3964_WAIT_FOR_BCC:
 660                 pInfo->last_rx = c;
 661                 on_receive_block(pInfo);
 662                 break;
 663         }
 664 }
 665
 666 static void receive_error(struct r3964_info *pInfo, const char flag)
 667 {
 668         switch (flag) {
 669         case TTY_NORMAL:
 670                 break;
 671         case TTY_BREAK:
 672                 TRACE_PE("received break");
 673                 pInfo->flags |= R3964_BREAK;
 674                 break;
 675         case TTY_PARITY:
 676                 TRACE_PE("parity error");
 677                 pInfo->flags |= R3964_PARITY;
 678                 break;
 679         case TTY_FRAME:
 680                 TRACE_PE("frame error");
 681                 pInfo->flags |= R3964_FRAME;
 682                 break;
 683         case TTY_OVERRUN:
 684                 TRACE_PE("frame overrun");
 685                 pInfo->flags |= R3964_OVERRUN;
 686                 break;
 687         default:
 688                 TRACE_PE("receive_error - unknown flag %d", flag);
 689                 pInfo->flags |= R3964_UNKNOWN;
 690                 break;
 691         }
 692 }
 693
 694 static void on_timeout(unsigned long priv)
 695 {
 696         struct r3964_info *pInfo = (void *)priv;
 697
 698         switch (pInfo->state) {
 699         case R3964_TX_REQUEST:
 700                 TRACE_PE("TX_REQUEST - timeout");
 701                 retry_transmit(pInfo);
 702                 break;
 703         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 704                 put_char(pInfo, NAK);
 705                 flush(pInfo);
 706                 retry_transmit(pInfo);
 707                 break;
 708         case R3964_WAIT_FOR_TX_ACK:
 709                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 710                 retry_transmit(pInfo);
 711                 break;
 712         case R3964_WAIT_FOR_RX_BUF:
 713                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 714                 put_char(pInfo, NAK);
 715                 flush(pInfo);
 716                 pInfo->state = R3964_IDLE;
 717                 break;
 718         case R3964_RECEIVING:
 719                 TRACE_PE("RECEIVING - timeout after %d chars",
 720                          pInfo->rx_position);
 721                 put_char(pInfo, NAK);
 722                 flush(pInfo);
 723                 pInfo->state = R3964_IDLE;
 724                 break;
 725         case R3964_WAIT_FOR_RX_REPEAT:
 726                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 727                 pInfo->state = R3964_IDLE;
 728                 break;
 729         case R3964_WAIT_FOR_BCC:
 730                 TRACE_PE("WAIT_FOR_BCC - timeout");
 731                 put_char(pInfo, NAK);
 732                 flush(pInfo);
 733                 pInfo->state = R3964_IDLE;
 734                 break;
 735         }
 736 }
 737
 738 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
 739                 struct pid *pid)
 740 {
 741         struct r3964_client_info *pClient;
 742
 743         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 744                 if (pClient->pid == pid) {
 745                         return pClient;
 746                 }
 747         }
 748         return NULL;
 749 }
 750
 751 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
 752 {
 753         struct r3964_client_info *pClient;
 754         struct r3964_client_info **ppClient;
 755         struct r3964_message *pMsg;
 756
 757         if ((arg & R3964_SIG_ALL) == 0) {
 758                 /* Remove client from client list */
 759                 for (ppClient = &pInfo->firstClient; *ppClient;
 760                      ppClient = &(*ppClient)->next) {
 761                         pClient = *ppClient;
 762
 763                         if (pClient->pid == pid) {
 764                                 TRACE_PS("removing client %d from client list",
 765                                          pid_nr(pid));
 766                                 *ppClient = pClient->next;
 767                                 while (pClient->msg_count) {
 768                                         pMsg = remove_msg(pInfo, pClient);
 769                                         if (pMsg) {
 770                                                 kfree(pMsg);
 771                                                 TRACE_M("enable_signals - msg "
 772                                                         "kfree %p", pMsg);
 773                                         }
 774                                 }
 775                                 put_pid(pClient->pid);
 776                                 kfree(pClient);
 777                                 TRACE_M("enable_signals - kfree %p", pClient);
 778                                 return 0;
 779                         }
 780                 }
 781                 return -EINVAL;
 782         } else {
 783                 pClient = findClient(pInfo, pid);
 784                 if (pClient) {
 785                         /* update signal options */
 786                         pClient->sig_flags = arg;
 787                 } else {
 788                         /* add client to client list */
 789                         pClient = kmalloc(sizeof(struct r3964_client_info),
 790                                         GFP_KERNEL);
 791                         TRACE_M("enable_signals - kmalloc %p", pClient);
 792                         if (pClient == NULL)
 793                                 return -ENOMEM;
 794
 795                         TRACE_PS("add client %d to client list", pid_nr(pid));
 796                         spin_lock_init(&pClient->lock);
 797                         pClient->sig_flags = arg;
 798                         pClient->pid = get_pid(pid);
 799                         pClient->next = pInfo->firstClient;
 800                         pClient->first_msg = NULL;
 801                         pClient->last_msg = NULL;
 802                         pClient->next_block_to_read = NULL;
 803                         pClient->msg_count = 0;
 804                         pInfo->firstClient = pClient;
 805                 }
 806         }
 807
 808         return 0;
 809 }
 810
 811 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 812                          unsigned char __user * buf)
 813 {
 814         struct r3964_client_info *pClient;
 815         struct r3964_block_header *block;
 816
 817         if (!buf) {
 818                 return -EINVAL;
 819         }
 820
 821         pClient = findClient(pInfo, pid);
 822         if (pClient == NULL) {
 823                 return -EINVAL;
 824         }
 825
 826         block = pClient->next_block_to_read;
 827         if (!block) {
 828                 return 0;
 829         } else {
 830                 if (copy_to_user(buf, block->data, block->length))
 831                         return -EFAULT;
 832
 833                 remove_client_block(pInfo, pClient);
 834                 return block->length;
 835         }
 836
 837         return -EINVAL;
 838 }
 839
 840 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 841                 int error_code, struct r3964_block_header *pBlock)
 842 {
 843         struct r3964_message *pMsg;
 844         unsigned long flags;
 845
 846         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
 847 queue_the_message:
 848
 849                 pMsg = kmalloc(sizeof(struct r3964_message),
 850                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
 851                 TRACE_M("add_msg - kmalloc %p", pMsg);
 852                 if (pMsg == NULL) {
 853                         return;
 854                 }
 855
 856                 spin_lock_irqsave(&pClient->lock, flags);
 857
 858                 pMsg->msg_id = msg_id;
 859                 pMsg->arg = arg;
 860                 pMsg->error_code = error_code;
 861                 pMsg->block = pBlock;
 862                 pMsg->next = NULL;
 863
 864                 if (pClient->last_msg == NULL) {
 865                         pClient->first_msg = pClient->last_msg = pMsg;
 866                 } else {
 867                         pClient->last_msg->next = pMsg;
 868                         pClient->last_msg = pMsg;
 869                 }
 870
 871                 pClient->msg_count++;
 872
 873                 if (pBlock != NULL) {
 874                         pBlock->locks++;
 875                 }
 876                 spin_unlock_irqrestore(&pClient->lock, flags);
 877         } else {
 878                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
 879                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
 880                         pClient->last_msg->arg++;
 881                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 882                 } else {
 883                         msg_id = R3964_MSG_ACK;
 884                         arg = 0;
 885                         error_code = R3964_OVERFLOW;
 886                         pBlock = NULL;
 887                         TRACE_PE("add_msg - queue OVERFLOW-msg");
 888                         goto queue_the_message;
 889                 }
 890         }
 891         /* Send SIGIO signal to client process: */
 892         if (pClient->sig_flags & R3964_USE_SIGIO) {
 893                 kill_pid(pClient->pid, SIGIO, 1);
 894         }
 895 }
 896
 897 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 898                                         struct r3964_client_info *pClient)
 899 {
 900         struct r3964_message *pMsg = NULL;
 901         unsigned long flags;
 902
 903         if (pClient->first_msg) {
 904                 spin_lock_irqsave(&pClient->lock, flags);
 905
 906                 pMsg = pClient->first_msg;
 907                 pClient->first_msg = pMsg->next;
 908                 if (pClient->first_msg == NULL) {
 909                         pClient->last_msg = NULL;
 910                 }
 911
 912                 pClient->msg_count--;
 913                 if (pMsg->block) {
 914                         remove_client_block(pInfo, pClient);
 915                         pClient->next_block_to_read = pMsg->block;
 916                 }
 917                 spin_unlock_irqrestore(&pClient->lock, flags);
 918         }
 919         return pMsg;
 920 }
 921
 922 static void remove_client_block(struct r3964_info *pInfo,
 923                                 struct r3964_client_info *pClient)
 924 {
 925         struct r3964_block_header *block;
 926
 927         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
 928
 929         block = pClient->next_block_to_read;
 930         if (block) {
 931                 block->locks--;
 932                 if (block->locks == 0) {
 933                         remove_from_rx_queue(pInfo, block);
 934                 }
 935         }
 936         pClient->next_block_to_read = NULL;
 937 }
 938
 939 /*************************************************************
 940  * Line discipline routines
 941  *************************************************************/
 942
 943 static int r3964_open(struct tty_struct *tty)
 944 {
 945         struct r3964_info *pInfo;
 946
 947         TRACE_L("open");
 948         TRACE_L("tty=%p, PID=%d, disc_data=%p",
 949                 tty, current->pid, tty->disc_data);
 950
 951         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
 952         TRACE_M("r3964_open - info kmalloc %p", pInfo);
 953
 954         if (!pInfo) {
 955                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
 956                 return -ENOMEM;
 957         }
 958
 959         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
 960         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
 961
 962         if (!pInfo->rx_buf) {
 963                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
 964                 kfree(pInfo);
 965                 TRACE_M("r3964_open - info kfree %p", pInfo);
 966                 return -ENOMEM;
 967         }
 968
 969         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
 970         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
 971
 972         if (!pInfo->tx_buf) {
 973                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
 974                 kfree(pInfo->rx_buf);
 975                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
 976                 kfree(pInfo);
 977                 TRACE_M("r3964_open - info kfree %p", pInfo);
 978                 return -ENOMEM;
 979         }
 980
 981         spin_lock_init(&pInfo->lock);
 982         pInfo->tty = tty;
 983         init_waitqueue_head(&pInfo->read_wait);
 984         pInfo->priority = R3964_MASTER;
 985         pInfo->rx_first = pInfo->rx_last = NULL;
 986         pInfo->tx_first = pInfo->tx_last = NULL;
 987         pInfo->rx_position = 0;
 988         pInfo->tx_position = 0;
 989         pInfo->last_rx = 0;
 990         pInfo->blocks_in_rx_queue = 0;
 991         pInfo->firstClient = NULL;
 992         pInfo->state = R3964_IDLE;
 993         pInfo->flags = R3964_DEBUG;
 994         pInfo->nRetry = 0;
 995
 996         tty->disc_data = pInfo;
 997         tty->receive_room = 65536;
 998
 999         setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
1000
1001         return 0;
1002 }
1003
1004 static void r3964_close(struct tty_struct *tty)
1005 {
1006         struct r3964_info *pInfo = tty->disc_data;
1007         struct r3964_client_info *pClient, *pNext;
1008         struct r3964_message *pMsg;
1009         struct r3964_block_header *pHeader, *pNextHeader;
1010         unsigned long flags;
1011
1012         TRACE_L("close");
1013
1014         /*
1015          * Make sure that our task queue isn't activated.  If it
1016          * is, take it out of the linked list.
1017          */
1018         del_timer_sync(&pInfo->tmr);
1019
1020         /* Remove client-structs and message queues: */
1021         pClient = pInfo->firstClient;
1022         while (pClient) {
1023                 pNext = pClient->next;
1024                 while (pClient->msg_count) {
1025                         pMsg = remove_msg(pInfo, pClient);
1026                         if (pMsg) {
1027                                 kfree(pMsg);
1028                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1029                         }
1030                 }
1031                 put_pid(pClient->pid);
1032                 kfree(pClient);
1033                 TRACE_M("r3964_close - client kfree %p", pClient);
1034                 pClient = pNext;
1035         }
1036         /* Remove jobs from tx_queue: */
1037         spin_lock_irqsave(&pInfo->lock, flags);
1038         pHeader = pInfo->tx_first;
1039         pInfo->tx_first = pInfo->tx_last = NULL;
1040         spin_unlock_irqrestore(&pInfo->lock, flags);
1041
1042         while (pHeader) {
1043                 pNextHeader = pHeader->next;
1044                 kfree(pHeader);
1045                 pHeader = pNextHeader;
1046         }
1047
1048         /* Free buffers: */
1049         wake_up_interruptible(&pInfo->read_wait);
1050         kfree(pInfo->rx_buf);
1051         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1052         kfree(pInfo->tx_buf);
1053         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1054         kfree(pInfo);
1055         TRACE_M("r3964_close - info kfree %p", pInfo);
1056 }
1057
1058 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1059                           unsigned char __user * buf, size_t nr)
1060 {
1061         struct r3964_info *pInfo = tty->disc_data;
1062         struct r3964_client_info *pClient;
1063         struct r3964_message *pMsg;
1064         struct r3964_client_message theMsg;
1065         int ret;
1066
1067         TRACE_L("read()");
1068
1069         lock_kernel();
1070
1071         pClient = findClient(pInfo, task_pid(current));
1072         if (pClient) {
1073                 pMsg = remove_msg(pInfo, pClient);
1074                 if (pMsg == NULL) {
1075                         /* no messages available. */
1076                         if (file->f_flags & O_NONBLOCK) {
1077                                 ret = -EAGAIN;
1078                                 goto unlock;
1079                         }
1080                         /* block until there is a message: */
1081                         wait_event_interruptible(pInfo->read_wait,
1082                                         (pMsg = remove_msg(pInfo, pClient)));
1083                 }
1084
1085                 /* If we still haven't got a message, we must have been signalled */
1086
1087                 if (!pMsg) {
1088                         ret = -EINTR;
1089                         goto unlock;
1090                 }
1091
1092                 /* deliver msg to client process: */
1093                 theMsg.msg_id = pMsg->msg_id;
1094                 theMsg.arg = pMsg->arg;
1095                 theMsg.error_code = pMsg->error_code;
1096                 ret = sizeof(struct r3964_client_message);
1097
1098                 kfree(pMsg);
1099                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1100
1101                 if (copy_to_user(buf, &theMsg, ret)) {
1102                         ret = -EFAULT;
1103                         goto unlock;
1104                 }
1105
1106                 TRACE_PS("read - return %d", ret);
1107                 goto unlock;
1108         }
1109         ret = -EPERM;
1110 unlock:
1111         unlock_kernel();
1112         return ret;
1113 }
1114
1115 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1116                            const unsigned char *data, size_t count)
1117 {
1118         struct r3964_info *pInfo = tty->disc_data;
1119         struct r3964_block_header *pHeader;
1120         struct r3964_client_info *pClient;
1121         unsigned char *new_data;
1122
1123         TRACE_L("write request, %d characters", count);
1124 /*
1125  * Verify the pointers
1126  */
1127
1128         if (!pInfo)
1129                 return -EIO;
1130
1131 /*
1132  * Ensure that the caller does not wish to send too much.
1133  */
1134         if (count > R3964_MTU) {
1135                 if (pInfo->flags & R3964_DEBUG) {
1136                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1137                                 "packet from %u to mtu %d", count, R3964_MTU);
1138                 }
1139                 count = R3964_MTU;
1140         }
1141 /*
1142  * Allocate a buffer for the data and copy it from the buffer with header prepended
1143  */
1144         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1145                         GFP_KERNEL);
1146         TRACE_M("r3964_write - kmalloc %p", new_data);
1147         if (new_data == NULL) {
1148                 if (pInfo->flags & R3964_DEBUG) {
1149                         printk(KERN_ERR "r3964_write: no memory\n");
1150                 }
1151                 return -ENOSPC;
1152         }
1153
1154         pHeader = (struct r3964_block_header *)new_data;
1155         pHeader->data = new_data + sizeof(struct r3964_block_header);
1156         pHeader->length = count;
1157         pHeader->locks = 0;
1158         pHeader->owner = NULL;
1159
1160         lock_kernel();
1161
1162         pClient = findClient(pInfo, task_pid(current));
1163         if (pClient) {
1164                 pHeader->owner = pClient;
1165         }
1166
1167         memcpy(pHeader->data, data, count);     /* We already verified this */
1168
1169         if (pInfo->flags & R3964_DEBUG) {
1170                 dump_block(pHeader->data, count);
1171         }
1172
1173 /*
1174  * Add buffer to transmit-queue:
1175  */
1176         add_tx_queue(pInfo, pHeader);
1177         trigger_transmit(pInfo);
1178
1179         unlock_kernel();
1180
1181         return 0;
1182 }
1183
1184 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1185                 unsigned int cmd, unsigned long arg)
1186 {
1187         struct r3964_info *pInfo = tty->disc_data;
1188         if (pInfo == NULL)
1189                 return -EINVAL;
1190         switch (cmd) {
1191         case R3964_ENABLE_SIGNALS:
1192                 return enable_signals(pInfo, task_pid(current), arg);
1193         case R3964_SETPRIORITY:
1194                 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1195                         return -EINVAL;
1196                 pInfo->priority = arg & 0xff;
1197                 return 0;
1198         case R3964_USE_BCC:
1199                 if (arg)
1200                         pInfo->flags |= R3964_BCC;
1201                 else
1202                         pInfo->flags &= ~R3964_BCC;
1203                 return 0;
1204         case R3964_READ_TELEGRAM:
1205                 return read_telegram(pInfo, task_pid(current),
1206                                 (unsigned char __user *)arg);
1207         default:
1208                 return -ENOIOCTLCMD;
1209         }
1210 }
1211
1212 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1213 {
1214         TRACE_L("set_termios");
1215 }
1216
1217 /* Called without the kernel lock held - fine */
1218 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1219                         struct poll_table_struct *wait)
1220 {
1221         struct r3964_info *pInfo = tty->disc_data;
1222         struct r3964_client_info *pClient;
1223         struct r3964_message *pMsg = NULL;
1224         unsigned long flags;
1225         int result = POLLOUT;
1226
1227         TRACE_L("POLL");
1228
1229         pClient = findClient(pInfo, task_pid(current));
1230         if (pClient) {
1231                 poll_wait(file, &pInfo->read_wait, wait);
1232                 spin_lock_irqsave(&pInfo->lock, flags);
1233                 pMsg = pClient->first_msg;
1234                 spin_unlock_irqrestore(&pInfo->lock, flags);
1235                 if (pMsg)
1236                         result |= POLLIN | POLLRDNORM;
1237         } else {
1238                 result = -EINVAL;
1239         }
1240         return result;
1241 }
1242
1243 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1244                         char *fp, int count)
1245 {
1246         struct r3964_info *pInfo = tty->disc_data;
1247         const unsigned char *p;
1248         char *f, flags = 0;
1249         int i;
1250
1251         for (i = count, p = cp, f = fp; i; i--, p++) {
1252                 if (f)
1253                         flags = *f++;
1254                 if (flags == TTY_NORMAL) {
1255                         receive_char(pInfo, *p);
1256                 } else {
1257                         receive_error(pInfo, flags);
1258                 }
1259
1260         }
1261 }
1262
1263 MODULE_LICENSE("GPL");
1264 MODULE_ALIAS_LDISC(N_R3964);