kernel/drivers/tty/n_r3964.c

   1 /* r3964 linediscipline for linux
   2  *
   3  * -----------------------------------------------------------
   4  * Copyright by
   5  * Philips Automation Projects
   6  * Kassel (Germany)
   7  * -----------------------------------------------------------
   8  * This software may be used and distributed according to the terms of
   9  * the GNU General Public License, incorporated herein by reference.
  10  *
  11  * Author:
  12  * L. Haag
  13  *
  14  * $Log: n_r3964.c,v $
  15  * Revision 1.10  2001/03/18 13:02:24  dwmw2
  16  * Fix timer usage, use spinlocks properly.
  17  *
  18  * Revision 1.9  2001/03/18 12:52:14  dwmw2
  19  * Merge changes in 2.4.2
  20  *
  21  * Revision 1.8  2000/03/23 14:14:54  dwmw2
  22  * Fix race in sleeping in r3964_read()
  23  *
  24  * Revision 1.7  1999/28/08 11:41:50  dwmw2
  25  * Port to 2.3 kernel
  26  *
  27  * Revision 1.6  1998/09/30 00:40:40  dwmw2
  28  * Fixed compilation on 2.0.x kernels
  29  * Updated to newly registered tty-ldisc number 9
  30  *
  31  * Revision 1.5  1998/09/04 21:57:36  dwmw2
  32  * Signal handling bug fixes, port to 2.1.x.
  33  *
  34  * Revision 1.4  1998/04/02 20:26:59  lhaag
  35  * select, blocking, ...
  36  *
  37  * Revision 1.3  1998/02/12 18:58:43  root
  38  * fixed some memory leaks
  39  * calculation of checksum characters
  40  *
  41  * Revision 1.2  1998/02/07 13:03:34  root
  42  * ioctl read_telegram
  43  *
  44  * Revision 1.1  1998/02/06 19:21:03  root
  45  * Initial revision
  46  *
  47  *
  48  */
  49
  50 #include <linux/module.h>
  51 #include <linux/kernel.h>
  52 #include <linux/sched.h>
  53 #include <linux/types.h>
  54 #include <linux/fcntl.h>
  55 #include <linux/interrupt.h>
  56 #include <linux/ptrace.h>
  57 #include <linux/ioport.h>
  58 #include <linux/in.h>
  59 #include <linux/slab.h>
  60 #include <linux/tty.h>
  61 #include <linux/errno.h>
  62 #include <linux/string.h>       /* used in new tty drivers */
  63 #include <linux/signal.h>       /* used in new tty drivers */
  64 #include <linux/ioctl.h>
  65 #include <linux/n_r3964.h>
  66 #include <linux/poll.h>
  67 #include <linux/init.h>
  68 #include <asm/uaccess.h>
  69
  70 /*#define DEBUG_QUEUE*/
  71
  72 /* Log successful handshake and protocol operations  */
  73 /*#define DEBUG_PROTO_S*/
  74
  75 /* Log handshake and protocol errors: */
  76 /*#define DEBUG_PROTO_E*/
  77
  78 /* Log Linediscipline operations (open, close, read, write...): */
  79 /*#define DEBUG_LDISC*/
  80
  81 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
  82 /*#define DEBUG_MODUL*/
  83
  84 /* Macro helpers for debug output: */
  85 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
  86
  87 #ifdef DEBUG_MODUL
  88 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
  89 #else
  90 #define TRACE_M(fmt, arg...) do {} while (0)
  91 #endif
  92 #ifdef DEBUG_PROTO_S
  93 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
  94 #else
  95 #define TRACE_PS(fmt, arg...) do {} while (0)
  96 #endif
  97 #ifdef DEBUG_PROTO_E
  98 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
  99 #else
 100 #define TRACE_PE(fmt, arg...) do {} while (0)
 101 #endif
 102 #ifdef DEBUG_LDISC
 103 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
 104 #else
 105 #define TRACE_L(fmt, arg...) do {} while (0)
 106 #endif
 107 #ifdef DEBUG_QUEUE
 108 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
 109 #else
 110 #define TRACE_Q(fmt, arg...) do {} while (0)
 111 #endif
 112 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
 113 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
 114 static void put_char(struct r3964_info *pInfo, unsigned char ch);
 115 static void trigger_transmit(struct r3964_info *pInfo);
 116 static void retry_transmit(struct r3964_info *pInfo);
 117 static void transmit_block(struct r3964_info *pInfo);
 118 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
 119 static void receive_error(struct r3964_info *pInfo, const char flag);
 120 static void on_timeout(unsigned long priv);
 121 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
 122 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 123                 unsigned char __user * buf);
 124 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 125                 int error_code, struct r3964_block_header *pBlock);
 126 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 127                 struct r3964_client_info *pClient);
 128 static void remove_client_block(struct r3964_info *pInfo,
 129                 struct r3964_client_info *pClient);
 130
 131 static int r3964_open(struct tty_struct *tty);
 132 static void r3964_close(struct tty_struct *tty);
 133 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
 134                 unsigned char __user * buf, size_t nr);
 135 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
 136                 const unsigned char *buf, size_t nr);
 137 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
 138                 unsigned int cmd, unsigned long arg);
 139 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
 140 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
 141                 struct poll_table_struct *wait);
 142 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 143                 char *fp, int count);
 144
 145 static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
 146         .owner = THIS_MODULE,
 147         .magic = TTY_LDISC_MAGIC,
 148         .name = "R3964",
 149         .open = r3964_open,
 150         .close = r3964_close,
 151         .read = r3964_read,
 152         .write = r3964_write,
 153         .ioctl = r3964_ioctl,
 154         .set_termios = r3964_set_termios,
 155         .poll = r3964_poll,
 156         .receive_buf = r3964_receive_buf,
 157 };
 158
 159 static void dump_block(const unsigned char *block, unsigned int length)
 160 {
 161         unsigned int i, j;
 162         char linebuf[16 * 3 + 1];
 163
 164         for (i = 0; i < length; i += 16) {
 165                 for (j = 0; (j < 16) && (j + i < length); j++) {
 166                         sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
 167                 }
 168                 linebuf[3 * j] = '\0';
 169                 TRACE_PS("%s", linebuf);
 170         }
 171 }
 172
 173 /*************************************************************
 174  * Driver initialisation
 175  *************************************************************/
 176
 177 /*************************************************************
 178  * Module support routines
 179  *************************************************************/
 180
 181 static void __exit r3964_exit(void)
 182 {
 183         int status;
 184
 185         TRACE_M("cleanup_module()");
 186
 187         status = tty_unregister_ldisc(N_R3964);
 188
 189         if (status != 0) {
 190                 printk(KERN_ERR "r3964: error unregistering linediscipline: "
 191                                 "%d\n", status);
 192         } else {
 193                 TRACE_L("linediscipline successfully unregistered");
 194         }
 195 }
 196
 197 static int __init r3964_init(void)
 198 {
 199         int status;
 200
 201         printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
 202
 203         /*
 204          * Register the tty line discipline
 205          */
 206
 207         status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
 208         if (status == 0) {
 209                 TRACE_L("line discipline %d registered", N_R3964);
 210                 TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 211                         tty_ldisc_N_R3964.num);
 212                 TRACE_L("open=%p", tty_ldisc_N_R3964.open);
 213                 TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
 214         } else {
 215                 printk(KERN_ERR "r3964: error registering line discipline: "
 216                                 "%d\n", status);
 217         }
 218         return status;
 219 }
 220
 221 module_init(r3964_init);
 222 module_exit(r3964_exit);
 223
 224 /*************************************************************
 225  * Protocol implementation routines
 226  *************************************************************/
 227
 228 static void add_tx_queue(struct r3964_info *pInfo,
 229                          struct r3964_block_header *pHeader)
 230 {
 231         unsigned long flags;
 232
 233         spin_lock_irqsave(&pInfo->lock, flags);
 234
 235         pHeader->next = NULL;
 236
 237         if (pInfo->tx_last == NULL) {
 238                 pInfo->tx_first = pInfo->tx_last = pHeader;
 239         } else {
 240                 pInfo->tx_last->next = pHeader;
 241                 pInfo->tx_last = pHeader;
 242         }
 243
 244         spin_unlock_irqrestore(&pInfo->lock, flags);
 245
 246         TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
 247                 pHeader, pHeader->length, pInfo->tx_first);
 248 }
 249
 250 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 251 {
 252         struct r3964_block_header *pHeader;
 253         unsigned long flags;
 254 #ifdef DEBUG_QUEUE
 255         struct r3964_block_header *pDump;
 256 #endif
 257
 258         pHeader = pInfo->tx_first;
 259
 260         if (pHeader == NULL)
 261                 return;
 262
 263 #ifdef DEBUG_QUEUE
 264         printk("r3964: remove_from_tx_queue: %p, length %u - ",
 265                 pHeader, pHeader->length);
 266         for (pDump = pHeader; pDump; pDump = pDump->next)
 267                 printk("%p ", pDump);
 268         printk("\n");
 269 #endif
 270
 271         if (pHeader->owner) {
 272                 if (error_code) {
 273                         add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 274                                 error_code, NULL);
 275                 } else {
 276                         add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 277                                 error_code, NULL);
 278                 }
 279                 wake_up_interruptible(&pInfo->tty->read_wait);
 280         }
 281
 282         spin_lock_irqsave(&pInfo->lock, flags);
 283
 284         pInfo->tx_first = pHeader->next;
 285         if (pInfo->tx_first == NULL) {
 286                 pInfo->tx_last = NULL;
 287         }
 288
 289         spin_unlock_irqrestore(&pInfo->lock, flags);
 290
 291         kfree(pHeader);
 292         TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
 293
 294         TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
 295                 pInfo->tx_first, pInfo->tx_last);
 296 }
 297
 298 static void add_rx_queue(struct r3964_info *pInfo,
 299                          struct r3964_block_header *pHeader)
 300 {
 301         unsigned long flags;
 302
 303         spin_lock_irqsave(&pInfo->lock, flags);
 304
 305         pHeader->next = NULL;
 306
 307         if (pInfo->rx_last == NULL) {
 308                 pInfo->rx_first = pInfo->rx_last = pHeader;
 309         } else {
 310                 pInfo->rx_last->next = pHeader;
 311                 pInfo->rx_last = pHeader;
 312         }
 313         pInfo->blocks_in_rx_queue++;
 314
 315         spin_unlock_irqrestore(&pInfo->lock, flags);
 316
 317         TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
 318                 pHeader, pHeader->length,
 319                 pInfo->rx_first, pInfo->blocks_in_rx_queue);
 320 }
 321
 322 static void remove_from_rx_queue(struct r3964_info *pInfo,
 323                                  struct r3964_block_header *pHeader)
 324 {
 325         unsigned long flags;
 326         struct r3964_block_header *pFind;
 327
 328         if (pHeader == NULL)
 329                 return;
 330
 331         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 332                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 333         TRACE_Q("remove_from_rx_queue: %p, length %u",
 334                 pHeader, pHeader->length);
 335
 336         spin_lock_irqsave(&pInfo->lock, flags);
 337
 338         if (pInfo->rx_first == pHeader) {
 339                 /* Remove the first block in the linked list: */
 340                 pInfo->rx_first = pHeader->next;
 341
 342                 if (pInfo->rx_first == NULL) {
 343                         pInfo->rx_last = NULL;
 344                 }
 345                 pInfo->blocks_in_rx_queue--;
 346         } else {
 347                 /* Find block to remove: */
 348                 for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
 349                         if (pFind->next == pHeader) {
 350                                 /* Got it. */
 351                                 pFind->next = pHeader->next;
 352                                 pInfo->blocks_in_rx_queue--;
 353                                 if (pFind->next == NULL) {
 354                                         /* Oh, removed the last one! */
 355                                         pInfo->rx_last = pFind;
 356                                 }
 357                                 break;
 358                         }
 359                 }
 360         }
 361
 362         spin_unlock_irqrestore(&pInfo->lock, flags);
 363
 364         kfree(pHeader);
 365         TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
 366
 367         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 368                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 369 }
 370
 371 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 372 {
 373         struct tty_struct *tty = pInfo->tty;
 374         /* FIXME: put_char should not be called from an IRQ */
 375         tty_put_char(tty, ch);
 376         pInfo->bcc ^= ch;
 377 }
 378
 379 static void flush(struct r3964_info *pInfo)
 380 {
 381         struct tty_struct *tty = pInfo->tty;
 382
 383         if (tty == NULL || tty->ops->flush_chars == NULL)
 384                 return;
 385         tty->ops->flush_chars(tty);
 386 }
 387
 388 static void trigger_transmit(struct r3964_info *pInfo)
 389 {
 390         unsigned long flags;
 391
 392         spin_lock_irqsave(&pInfo->lock, flags);
 393
 394         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
 395                 pInfo->state = R3964_TX_REQUEST;
 396                 pInfo->nRetry = 0;
 397                 pInfo->flags &= ~R3964_ERROR;
 398                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 399
 400                 spin_unlock_irqrestore(&pInfo->lock, flags);
 401
 402                 TRACE_PS("trigger_transmit - sent STX");
 403
 404                 put_char(pInfo, STX);
 405                 flush(pInfo);
 406
 407                 pInfo->bcc = 0;
 408         } else {
 409                 spin_unlock_irqrestore(&pInfo->lock, flags);
 410         }
 411 }
 412
 413 static void retry_transmit(struct r3964_info *pInfo)
 414 {
 415         if (pInfo->nRetry < R3964_MAX_RETRIES) {
 416                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
 417                 pInfo->bcc = 0;
 418                 put_char(pInfo, STX);
 419                 flush(pInfo);
 420                 pInfo->state = R3964_TX_REQUEST;
 421                 pInfo->nRetry++;
 422                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 423         } else {
 424                 TRACE_PE("transmission failed after %d retries",
 425                          R3964_MAX_RETRIES);
 426
 427                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 428
 429                 put_char(pInfo, NAK);
 430                 flush(pInfo);
 431                 pInfo->state = R3964_IDLE;
 432
 433                 trigger_transmit(pInfo);
 434         }
 435 }
 436
 437 static void transmit_block(struct r3964_info *pInfo)
 438 {
 439         struct tty_struct *tty = pInfo->tty;
 440         struct r3964_block_header *pBlock = pInfo->tx_first;
 441         int room = 0;
 442
 443         if (tty == NULL || pBlock == NULL) {
 444                 return;
 445         }
 446
 447         room = tty_write_room(tty);
 448
 449         TRACE_PS("transmit_block %p, room %d, length %d",
 450                  pBlock, room, pBlock->length);
 451
 452         while (pInfo->tx_position < pBlock->length) {
 453                 if (room < 2)
 454                         break;
 455
 456                 if (pBlock->data[pInfo->tx_position] == DLE) {
 457                         /* send additional DLE char: */
 458                         put_char(pInfo, DLE);
 459                 }
 460                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 461
 462                 room--;
 463         }
 464
 465         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
 466                 put_char(pInfo, DLE);
 467                 put_char(pInfo, ETX);
 468                 if (pInfo->flags & R3964_BCC) {
 469                         put_char(pInfo, pInfo->bcc);
 470                 }
 471                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
 472                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 473         }
 474         flush(pInfo);
 475 }
 476
 477 static void on_receive_block(struct r3964_info *pInfo)
 478 {
 479         unsigned int length;
 480         struct r3964_client_info *pClient;
 481         struct r3964_block_header *pBlock;
 482
 483         length = pInfo->rx_position;
 484
 485         /* compare byte checksum characters: */
 486         if (pInfo->flags & R3964_BCC) {
 487                 if (pInfo->bcc != pInfo->last_rx) {
 488                         TRACE_PE("checksum error - got %x but expected %x",
 489                                  pInfo->last_rx, pInfo->bcc);
 490                         pInfo->flags |= R3964_CHECKSUM;
 491                 }
 492         }
 493
 494         /* check for errors (parity, overrun,...): */
 495         if (pInfo->flags & R3964_ERROR) {
 496                 TRACE_PE("on_receive_block - transmission failed error %x",
 497                          pInfo->flags & R3964_ERROR);
 498
 499                 put_char(pInfo, NAK);
 500                 flush(pInfo);
 501                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
 502                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
 503                         pInfo->nRetry++;
 504                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 505                 } else {
 506                         TRACE_PE("on_receive_block - failed after max retries");
 507                         pInfo->state = R3964_IDLE;
 508                 }
 509                 return;
 510         }
 511
 512         /* received block; submit DLE: */
 513         put_char(pInfo, DLE);
 514         flush(pInfo);
 515         del_timer_sync(&pInfo->tmr);
 516         TRACE_PS(" rx success: got %d chars", length);
 517
 518         /* prepare struct r3964_block_header: */
 519         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
 520                         GFP_KERNEL);
 521         TRACE_M("on_receive_block - kmalloc %p", pBlock);
 522
 523         if (pBlock == NULL)
 524                 return;
 525
 526         pBlock->length = length;
 527         pBlock->data = ((unsigned char *)pBlock) +
 528                         sizeof(struct r3964_block_header);
 529         pBlock->locks = 0;
 530         pBlock->next = NULL;
 531         pBlock->owner = NULL;
 532
 533         memcpy(pBlock->data, pInfo->rx_buf, length);
 534
 535         /* queue block into rx_queue: */
 536         add_rx_queue(pInfo, pBlock);
 537
 538         /* notify attached client processes: */
 539         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 540                 if (pClient->sig_flags & R3964_SIG_DATA) {
 541                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
 542                                 pBlock);
 543                 }
 544         }
 545         wake_up_interruptible(&pInfo->tty->read_wait);
 546
 547         pInfo->state = R3964_IDLE;
 548
 549         trigger_transmit(pInfo);
 550 }
 551
 552 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 553 {
 554         switch (pInfo->state) {
 555         case R3964_TX_REQUEST:
 556                 if (c == DLE) {
 557                         TRACE_PS("TX_REQUEST - got DLE");
 558
 559                         pInfo->state = R3964_TRANSMITTING;
 560                         pInfo->tx_position = 0;
 561
 562                         transmit_block(pInfo);
 563                 } else if (c == STX) {
 564                         if (pInfo->nRetry == 0) {
 565                                 TRACE_PE("TX_REQUEST - init conflict");
 566                                 if (pInfo->priority == R3964_SLAVE) {
 567                                         goto start_receiving;
 568                                 }
 569                         } else {
 570                                 TRACE_PE("TX_REQUEST - secondary init "
 571                                         "conflict!? Switching to SLAVE mode "
 572                                         "for next rx.");
 573                                 goto start_receiving;
 574                         }
 575                 } else {
 576                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 577                         retry_transmit(pInfo);
 578                 }
 579                 break;
 580         case R3964_TRANSMITTING:
 581                 if (c == NAK) {
 582                         TRACE_PE("TRANSMITTING - got NAK");
 583                         retry_transmit(pInfo);
 584                 } else {
 585                         TRACE_PE("TRANSMITTING - got invalid char");
 586
 587                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 588                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 589                 }
 590                 break;
 591         case R3964_WAIT_FOR_TX_ACK:
 592                 if (c == DLE) {
 593                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 594                         remove_from_tx_queue(pInfo, R3964_OK);
 595
 596                         pInfo->state = R3964_IDLE;
 597                         trigger_transmit(pInfo);
 598                 } else {
 599                         retry_transmit(pInfo);
 600                 }
 601                 break;
 602         case R3964_WAIT_FOR_RX_REPEAT:
 603                 /* FALLTHROUGH */
 604         case R3964_IDLE:
 605                 if (c == STX) {
 606                         /* Prevent rx_queue from overflow: */
 607                         if (pInfo->blocks_in_rx_queue >=
 608                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
 609                                 TRACE_PE("IDLE - got STX but no space in "
 610                                                 "rx_queue!");
 611                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
 612                                 mod_timer(&pInfo->tmr,
 613                                           jiffies + R3964_TO_NO_BUF);
 614                                 break;
 615                         }
 616 start_receiving:
 617                         /* Ok, start receiving: */
 618                         TRACE_PS("IDLE - got STX");
 619                         pInfo->rx_position = 0;
 620                         pInfo->last_rx = 0;
 621                         pInfo->flags &= ~R3964_ERROR;
 622                         pInfo->state = R3964_RECEIVING;
 623                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 624                         pInfo->nRetry = 0;
 625                         put_char(pInfo, DLE);
 626                         flush(pInfo);
 627                         pInfo->bcc = 0;
 628                 }
 629                 break;
 630         case R3964_RECEIVING:
 631                 if (pInfo->rx_position < RX_BUF_SIZE) {
 632                         pInfo->bcc ^= c;
 633
 634                         if (c == DLE) {
 635                                 if (pInfo->last_rx == DLE) {
 636                                         pInfo->last_rx = 0;
 637                                         goto char_to_buf;
 638                                 }
 639                                 pInfo->last_rx = DLE;
 640                                 break;
 641                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
 642                                 if (pInfo->flags & R3964_BCC) {
 643                                         pInfo->state = R3964_WAIT_FOR_BCC;
 644                                         mod_timer(&pInfo->tmr,
 645                                                   jiffies + R3964_TO_ZVZ);
 646                                 } else {
 647                                         on_receive_block(pInfo);
 648                                 }
 649                         } else {
 650                                 pInfo->last_rx = c;
 651 char_to_buf:
 652                                 pInfo->rx_buf[pInfo->rx_position++] = c;
 653                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 654                         }
 655                 }
 656                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 657                 break;
 658         case R3964_WAIT_FOR_BCC:
 659                 pInfo->last_rx = c;
 660                 on_receive_block(pInfo);
 661                 break;
 662         }
 663 }
 664
 665 static void receive_error(struct r3964_info *pInfo, const char flag)
 666 {
 667         switch (flag) {
 668         case TTY_NORMAL:
 669                 break;
 670         case TTY_BREAK:
 671                 TRACE_PE("received break");
 672                 pInfo->flags |= R3964_BREAK;
 673                 break;
 674         case TTY_PARITY:
 675                 TRACE_PE("parity error");
 676                 pInfo->flags |= R3964_PARITY;
 677                 break;
 678         case TTY_FRAME:
 679                 TRACE_PE("frame error");
 680                 pInfo->flags |= R3964_FRAME;
 681                 break;
 682         case TTY_OVERRUN:
 683                 TRACE_PE("frame overrun");
 684                 pInfo->flags |= R3964_OVERRUN;
 685                 break;
 686         default:
 687                 TRACE_PE("receive_error - unknown flag %d", flag);
 688                 pInfo->flags |= R3964_UNKNOWN;
 689                 break;
 690         }
 691 }
 692
 693 static void on_timeout(unsigned long priv)
 694 {
 695         struct r3964_info *pInfo = (void *)priv;
 696
 697         switch (pInfo->state) {
 698         case R3964_TX_REQUEST:
 699                 TRACE_PE("TX_REQUEST - timeout");
 700                 retry_transmit(pInfo);
 701                 break;
 702         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 703                 put_char(pInfo, NAK);
 704                 flush(pInfo);
 705                 retry_transmit(pInfo);
 706                 break;
 707         case R3964_WAIT_FOR_TX_ACK:
 708                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 709                 retry_transmit(pInfo);
 710                 break;
 711         case R3964_WAIT_FOR_RX_BUF:
 712                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 713                 put_char(pInfo, NAK);
 714                 flush(pInfo);
 715                 pInfo->state = R3964_IDLE;
 716                 break;
 717         case R3964_RECEIVING:
 718                 TRACE_PE("RECEIVING - timeout after %d chars",
 719                          pInfo->rx_position);
 720                 put_char(pInfo, NAK);
 721                 flush(pInfo);
 722                 pInfo->state = R3964_IDLE;
 723                 break;
 724         case R3964_WAIT_FOR_RX_REPEAT:
 725                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 726                 pInfo->state = R3964_IDLE;
 727                 break;
 728         case R3964_WAIT_FOR_BCC:
 729                 TRACE_PE("WAIT_FOR_BCC - timeout");
 730                 put_char(pInfo, NAK);
 731                 flush(pInfo);
 732                 pInfo->state = R3964_IDLE;
 733                 break;
 734         }
 735 }
 736
 737 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
 738                 struct pid *pid)
 739 {
 740         struct r3964_client_info *pClient;
 741
 742         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 743                 if (pClient->pid == pid) {
 744                         return pClient;
 745                 }
 746         }
 747         return NULL;
 748 }
 749
 750 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
 751 {
 752         struct r3964_client_info *pClient;
 753         struct r3964_client_info **ppClient;
 754         struct r3964_message *pMsg;
 755
 756         if ((arg & R3964_SIG_ALL) == 0) {
 757                 /* Remove client from client list */
 758                 for (ppClient = &pInfo->firstClient; *ppClient;
 759                      ppClient = &(*ppClient)->next) {
 760                         pClient = *ppClient;
 761
 762                         if (pClient->pid == pid) {
 763                                 TRACE_PS("removing client %d from client list",
 764                                          pid_nr(pid));
 765                                 *ppClient = pClient->next;
 766                                 while (pClient->msg_count) {
 767                                         pMsg = remove_msg(pInfo, pClient);
 768                                         if (pMsg) {
 769                                                 kfree(pMsg);
 770                                                 TRACE_M("enable_signals - msg "
 771                                                         "kfree %p", pMsg);
 772                                         }
 773                                 }
 774                                 put_pid(pClient->pid);
 775                                 kfree(pClient);
 776                                 TRACE_M("enable_signals - kfree %p", pClient);
 777                                 return 0;
 778                         }
 779                 }
 780                 return -EINVAL;
 781         } else {
 782                 pClient = findClient(pInfo, pid);
 783                 if (pClient) {
 784                         /* update signal options */
 785                         pClient->sig_flags = arg;
 786                 } else {
 787                         /* add client to client list */
 788                         pClient = kmalloc(sizeof(struct r3964_client_info),
 789                                         GFP_KERNEL);
 790                         TRACE_M("enable_signals - kmalloc %p", pClient);
 791                         if (pClient == NULL)
 792                                 return -ENOMEM;
 793
 794                         TRACE_PS("add client %d to client list", pid_nr(pid));
 795                         spin_lock_init(&pClient->lock);
 796                         pClient->sig_flags = arg;
 797                         pClient->pid = get_pid(pid);
 798                         pClient->next = pInfo->firstClient;
 799                         pClient->first_msg = NULL;
 800                         pClient->last_msg = NULL;
 801                         pClient->next_block_to_read = NULL;
 802                         pClient->msg_count = 0;
 803                         pInfo->firstClient = pClient;
 804                 }
 805         }
 806
 807         return 0;
 808 }
 809
 810 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 811                          unsigned char __user * buf)
 812 {
 813         struct r3964_client_info *pClient;
 814         struct r3964_block_header *block;
 815
 816         if (!buf) {
 817                 return -EINVAL;
 818         }
 819
 820         pClient = findClient(pInfo, pid);
 821         if (pClient == NULL) {
 822                 return -EINVAL;
 823         }
 824
 825         block = pClient->next_block_to_read;
 826         if (!block) {
 827                 return 0;
 828         } else {
 829                 if (copy_to_user(buf, block->data, block->length))
 830                         return -EFAULT;
 831
 832                 remove_client_block(pInfo, pClient);
 833                 return block->length;
 834         }
 835
 836         return -EINVAL;
 837 }
 838
 839 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 840                 int error_code, struct r3964_block_header *pBlock)
 841 {
 842         struct r3964_message *pMsg;
 843         unsigned long flags;
 844
 845         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
 846 queue_the_message:
 847
 848                 pMsg = kmalloc(sizeof(struct r3964_message),
 849                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
 850                 TRACE_M("add_msg - kmalloc %p", pMsg);
 851                 if (pMsg == NULL) {
 852                         return;
 853                 }
 854
 855                 spin_lock_irqsave(&pClient->lock, flags);
 856
 857                 pMsg->msg_id = msg_id;
 858                 pMsg->arg = arg;
 859                 pMsg->error_code = error_code;
 860                 pMsg->block = pBlock;
 861                 pMsg->next = NULL;
 862
 863                 if (pClient->last_msg == NULL) {
 864                         pClient->first_msg = pClient->last_msg = pMsg;
 865                 } else {
 866                         pClient->last_msg->next = pMsg;
 867                         pClient->last_msg = pMsg;
 868                 }
 869
 870                 pClient->msg_count++;
 871
 872                 if (pBlock != NULL) {
 873                         pBlock->locks++;
 874                 }
 875                 spin_unlock_irqrestore(&pClient->lock, flags);
 876         } else {
 877                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
 878                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
 879                         pClient->last_msg->arg++;
 880                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 881                 } else {
 882                         msg_id = R3964_MSG_ACK;
 883                         arg = 0;
 884                         error_code = R3964_OVERFLOW;
 885                         pBlock = NULL;
 886                         TRACE_PE("add_msg - queue OVERFLOW-msg");
 887                         goto queue_the_message;
 888                 }
 889         }
 890         /* Send SIGIO signal to client process: */
 891         if (pClient->sig_flags & R3964_USE_SIGIO) {
 892                 kill_pid(pClient->pid, SIGIO, 1);
 893         }
 894 }
 895
 896 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 897                                         struct r3964_client_info *pClient)
 898 {
 899         struct r3964_message *pMsg = NULL;
 900         unsigned long flags;
 901
 902         if (pClient->first_msg) {
 903                 spin_lock_irqsave(&pClient->lock, flags);
 904
 905                 pMsg = pClient->first_msg;
 906                 pClient->first_msg = pMsg->next;
 907                 if (pClient->first_msg == NULL) {
 908                         pClient->last_msg = NULL;
 909                 }
 910
 911                 pClient->msg_count--;
 912                 if (pMsg->block) {
 913                         remove_client_block(pInfo, pClient);
 914                         pClient->next_block_to_read = pMsg->block;
 915                 }
 916                 spin_unlock_irqrestore(&pClient->lock, flags);
 917         }
 918         return pMsg;
 919 }
 920
 921 static void remove_client_block(struct r3964_info *pInfo,
 922                                 struct r3964_client_info *pClient)
 923 {
 924         struct r3964_block_header *block;
 925
 926         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
 927
 928         block = pClient->next_block_to_read;
 929         if (block) {
 930                 block->locks--;
 931                 if (block->locks == 0) {
 932                         remove_from_rx_queue(pInfo, block);
 933                 }
 934         }
 935         pClient->next_block_to_read = NULL;
 936 }
 937
 938 /*************************************************************
 939  * Line discipline routines
 940  *************************************************************/
 941
 942 static int r3964_open(struct tty_struct *tty)
 943 {
 944         struct r3964_info *pInfo;
 945
 946         TRACE_L("open");
 947         TRACE_L("tty=%p, PID=%d, disc_data=%p",
 948                 tty, current->pid, tty->disc_data);
 949
 950         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
 951         TRACE_M("r3964_open - info kmalloc %p", pInfo);
 952
 953         if (!pInfo) {
 954                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
 955                 return -ENOMEM;
 956         }
 957
 958         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
 959         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
 960
 961         if (!pInfo->rx_buf) {
 962                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
 963                 kfree(pInfo);
 964                 TRACE_M("r3964_open - info kfree %p", pInfo);
 965                 return -ENOMEM;
 966         }
 967
 968         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
 969         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
 970
 971         if (!pInfo->tx_buf) {
 972                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
 973                 kfree(pInfo->rx_buf);
 974                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
 975                 kfree(pInfo);
 976                 TRACE_M("r3964_open - info kfree %p", pInfo);
 977                 return -ENOMEM;
 978         }
 979
 980         spin_lock_init(&pInfo->lock);
 981         mutex_init(&pInfo->read_lock);
 982         pInfo->tty = tty;
 983         pInfo->priority = R3964_MASTER;
 984         pInfo->rx_first = pInfo->rx_last = NULL;
 985         pInfo->tx_first = pInfo->tx_last = NULL;
 986         pInfo->rx_position = 0;
 987         pInfo->tx_position = 0;
 988         pInfo->last_rx = 0;
 989         pInfo->blocks_in_rx_queue = 0;
 990         pInfo->firstClient = NULL;
 991         pInfo->state = R3964_IDLE;
 992         pInfo->flags = R3964_DEBUG;
 993         pInfo->nRetry = 0;
 994
 995         tty->disc_data = pInfo;
 996         tty->receive_room = 65536;
 997
 998         setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
 999
1000         return 0;
1001 }
1002
1003 static void r3964_close(struct tty_struct *tty)
1004 {
1005         struct r3964_info *pInfo = tty->disc_data;
1006         struct r3964_client_info *pClient, *pNext;
1007         struct r3964_message *pMsg;
1008         struct r3964_block_header *pHeader, *pNextHeader;
1009         unsigned long flags;
1010
1011         TRACE_L("close");
1012
1013         /*
1014          * Make sure that our task queue isn't activated.  If it
1015          * is, take it out of the linked list.
1016          */
1017         del_timer_sync(&pInfo->tmr);
1018
1019         /* Remove client-structs and message queues: */
1020         pClient = pInfo->firstClient;
1021         while (pClient) {
1022                 pNext = pClient->next;
1023                 while (pClient->msg_count) {
1024                         pMsg = remove_msg(pInfo, pClient);
1025                         if (pMsg) {
1026                                 kfree(pMsg);
1027                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1028                         }
1029                 }
1030                 put_pid(pClient->pid);
1031                 kfree(pClient);
1032                 TRACE_M("r3964_close - client kfree %p", pClient);
1033                 pClient = pNext;
1034         }
1035         /* Remove jobs from tx_queue: */
1036         spin_lock_irqsave(&pInfo->lock, flags);
1037         pHeader = pInfo->tx_first;
1038         pInfo->tx_first = pInfo->tx_last = NULL;
1039         spin_unlock_irqrestore(&pInfo->lock, flags);
1040
1041         while (pHeader) {
1042                 pNextHeader = pHeader->next;
1043                 kfree(pHeader);
1044                 pHeader = pNextHeader;
1045         }
1046
1047         /* Free buffers: */
1048         kfree(pInfo->rx_buf);
1049         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1050         kfree(pInfo->tx_buf);
1051         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1052         kfree(pInfo);
1053         TRACE_M("r3964_close - info kfree %p", pInfo);
1054 }
1055
1056 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1057                           unsigned char __user * buf, size_t nr)
1058 {
1059         struct r3964_info *pInfo = tty->disc_data;
1060         struct r3964_client_info *pClient;
1061         struct r3964_message *pMsg;
1062         struct r3964_client_message theMsg;
1063         int ret;
1064
1065         TRACE_L("read()");
1066
1067         /*
1068          *      Internal serialization of reads.
1069          */
1070         if (file->f_flags & O_NONBLOCK) {
1071                 if (!mutex_trylock(&pInfo->read_lock))
1072                         return -EAGAIN;
1073         } else {
1074                 if (mutex_lock_interruptible(&pInfo->read_lock))
1075                         return -ERESTARTSYS;
1076         }
1077
1078         pClient = findClient(pInfo, task_pid(current));
1079         if (pClient) {
1080                 pMsg = remove_msg(pInfo, pClient);
1081                 if (pMsg == NULL) {
1082                         /* no messages available. */
1083                         if (file->f_flags & O_NONBLOCK) {
1084                                 ret = -EAGAIN;
1085                                 goto unlock;
1086                         }
1087                         /* block until there is a message: */
1088                         wait_event_interruptible(tty->read_wait,
1089                                         (pMsg = remove_msg(pInfo, pClient)));
1090                 }
1091
1092                 /* If we still haven't got a message, we must have been signalled */
1093
1094                 if (!pMsg) {
1095                         ret = -EINTR;
1096                         goto unlock;
1097                 }
1098
1099                 /* deliver msg to client process: */
1100                 theMsg.msg_id = pMsg->msg_id;
1101                 theMsg.arg = pMsg->arg;
1102                 theMsg.error_code = pMsg->error_code;
1103                 ret = sizeof(struct r3964_client_message);
1104
1105                 kfree(pMsg);
1106                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1107
1108                 if (copy_to_user(buf, &theMsg, ret)) {
1109                         ret = -EFAULT;
1110                         goto unlock;
1111                 }
1112
1113                 TRACE_PS("read - return %d", ret);
1114                 goto unlock;
1115         }
1116         ret = -EPERM;
1117 unlock:
1118         mutex_unlock(&pInfo->read_lock);
1119         return ret;
1120 }
1121
1122 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1123                            const unsigned char *data, size_t count)
1124 {
1125         struct r3964_info *pInfo = tty->disc_data;
1126         struct r3964_block_header *pHeader;
1127         struct r3964_client_info *pClient;
1128         unsigned char *new_data;
1129
1130         TRACE_L("write request, %d characters", count);
1131 /*
1132  * Verify the pointers
1133  */
1134
1135         if (!pInfo)
1136                 return -EIO;
1137
1138 /*
1139  * Ensure that the caller does not wish to send too much.
1140  */
1141         if (count > R3964_MTU) {
1142                 if (pInfo->flags & R3964_DEBUG) {
1143                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1144                                 "packet from %u to mtu %d", count, R3964_MTU);
1145                 }
1146                 count = R3964_MTU;
1147         }
1148 /*
1149  * Allocate a buffer for the data and copy it from the buffer with header prepended
1150  */
1151         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1152                         GFP_KERNEL);
1153         TRACE_M("r3964_write - kmalloc %p", new_data);
1154         if (new_data == NULL) {
1155                 if (pInfo->flags & R3964_DEBUG) {
1156                         printk(KERN_ERR "r3964_write: no memory\n");
1157                 }
1158                 return -ENOSPC;
1159         }
1160
1161         pHeader = (struct r3964_block_header *)new_data;
1162         pHeader->data = new_data + sizeof(struct r3964_block_header);
1163         pHeader->length = count;
1164         pHeader->locks = 0;
1165         pHeader->owner = NULL;
1166
1167         pClient = findClient(pInfo, task_pid(current));
1168         if (pClient) {
1169                 pHeader->owner = pClient;
1170         }
1171
1172         memcpy(pHeader->data, data, count);     /* We already verified this */
1173
1174         if (pInfo->flags & R3964_DEBUG) {
1175                 dump_block(pHeader->data, count);
1176         }
1177
1178 /*
1179  * Add buffer to transmit-queue:
1180  */
1181         add_tx_queue(pInfo, pHeader);
1182         trigger_transmit(pInfo);
1183
1184         return 0;
1185 }
1186
1187 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1188                 unsigned int cmd, unsigned long arg)
1189 {
1190         struct r3964_info *pInfo = tty->disc_data;
1191         if (pInfo == NULL)
1192                 return -EINVAL;
1193         switch (cmd) {
1194         case R3964_ENABLE_SIGNALS:
1195                 return enable_signals(pInfo, task_pid(current), arg);
1196         case R3964_SETPRIORITY:
1197                 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1198                         return -EINVAL;
1199                 pInfo->priority = arg & 0xff;
1200                 return 0;
1201         case R3964_USE_BCC:
1202                 if (arg)
1203                         pInfo->flags |= R3964_BCC;
1204                 else
1205                         pInfo->flags &= ~R3964_BCC;
1206                 return 0;
1207         case R3964_READ_TELEGRAM:
1208                 return read_telegram(pInfo, task_pid(current),
1209                                 (unsigned char __user *)arg);
1210         default:
1211                 return -ENOIOCTLCMD;
1212         }
1213 }
1214
1215 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1216 {
1217         TRACE_L("set_termios");
1218 }
1219
1220 /* Called without the kernel lock held - fine */
1221 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1222                         struct poll_table_struct *wait)
1223 {
1224         struct r3964_info *pInfo = tty->disc_data;
1225         struct r3964_client_info *pClient;
1226         struct r3964_message *pMsg = NULL;
1227         unsigned long flags;
1228         int result = POLLOUT;
1229
1230         TRACE_L("POLL");
1231
1232         pClient = findClient(pInfo, task_pid(current));
1233         if (pClient) {
1234                 poll_wait(file, &tty->read_wait, wait);
1235                 spin_lock_irqsave(&pInfo->lock, flags);
1236                 pMsg = pClient->first_msg;
1237                 spin_unlock_irqrestore(&pInfo->lock, flags);
1238                 if (pMsg)
1239                         result |= POLLIN | POLLRDNORM;
1240         } else {
1241                 result = -EINVAL;
1242         }
1243         return result;
1244 }
1245
1246 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1247                         char *fp, int count)
1248 {
1249         struct r3964_info *pInfo = tty->disc_data;
1250         const unsigned char *p;
1251         char *f, flags = TTY_NORMAL;
1252         int i;
1253
1254         for (i = count, p = cp, f = fp; i; i--, p++) {
1255                 if (f)
1256                         flags = *f++;
1257                 if (flags == TTY_NORMAL) {
1258                         receive_char(pInfo, *p);
1259                 } else {
1260                         receive_error(pInfo, flags);
1261                 }
1262
1263         }
1264 }
1265
1266 MODULE_LICENSE("GPL");
1267 MODULE_ALIAS_LDISC(N_R3964);