drivers/char/n_r3964.c

   1 /* r3964 linediscipline for linux
   2  *
   3  * -----------------------------------------------------------
   4  * Copyright by
   5  * Philips Automation Projects
   6  * Kassel (Germany)
   7  * http://www.pap-philips.de
   8  * -----------------------------------------------------------
   9  * This software may be used and distributed according to the terms of
  10  * the GNU General Public License, incorporated herein by reference.
  11  *
  12  * Author:
  13  * L. Haag
  14  *
  15  * $Log: n_r3964.c,v $
  16  * Revision 1.10  2001/03/18 13:02:24  dwmw2
  17  * Fix timer usage, use spinlocks properly.
  18  *
  19  * Revision 1.9  2001/03/18 12:52:14  dwmw2
  20  * Merge changes in 2.4.2
  21  *
  22  * Revision 1.8  2000/03/23 14:14:54  dwmw2
  23  * Fix race in sleeping in r3964_read()
  24  *
  25  * Revision 1.7  1999/28/08 11:41:50  dwmw2
  26  * Port to 2.3 kernel
  27  *
  28  * Revision 1.6  1998/09/30 00:40:40  dwmw2
  29  * Fixed compilation on 2.0.x kernels
  30  * Updated to newly registered tty-ldisc number 9
  31  *
  32  * Revision 1.5  1998/09/04 21:57:36  dwmw2
  33  * Signal handling bug fixes, port to 2.1.x.
  34  *
  35  * Revision 1.4  1998/04/02 20:26:59  lhaag
  36  * select, blocking, ...
  37  *
  38  * Revision 1.3  1998/02/12 18:58:43  root
  39  * fixed some memory leaks
  40  * calculation of checksum characters
  41  *
  42  * Revision 1.2  1998/02/07 13:03:34  root
  43  * ioctl read_telegram
  44  *
  45  * Revision 1.1  1998/02/06 19:21:03  root
  46  * Initial revision
  47  *
  48  *
  49  */
  50
  51 #include <linux/module.h>
  52 #include <linux/kernel.h>
  53 #include <linux/sched.h>
  54 #include <linux/types.h>
  55 #include <linux/fcntl.h>
  56 #include <linux/interrupt.h>
  57 #include <linux/ptrace.h>
  58 #include <linux/ioport.h>
  59 #include <linux/in.h>
  60 #include <linux/slab.h>
  61 #include <linux/tty.h>
  62 #include <linux/errno.h>
  63 #include <linux/string.h>       /* used in new tty drivers */
  64 #include <linux/signal.h>       /* used in new tty drivers */
  65 #include <linux/ioctl.h>
  66 #include <linux/n_r3964.h>
  67 #include <linux/poll.h>
  68 #include <linux/init.h>
  69 #include <asm/uaccess.h>
  70
  71 /*#define DEBUG_QUEUE*/
  72
  73 /* Log successful handshake and protocol operations  */
  74 /*#define DEBUG_PROTO_S*/
  75
  76 /* Log handshake and protocol errors: */
  77 /*#define DEBUG_PROTO_E*/
  78
  79 /* Log Linediscipline operations (open, close, read, write...): */
  80 /*#define DEBUG_LDISC*/
  81
  82 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
  83 /*#define DEBUG_MODUL*/
  84
  85 /* Macro helpers for debug output: */
  86 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
  87
  88 #ifdef DEBUG_MODUL
  89 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
  90 #else
  91 #define TRACE_M(fmt, arg...) do {} while (0)
  92 #endif
  93 #ifdef DEBUG_PROTO_S
  94 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
  95 #else
  96 #define TRACE_PS(fmt, arg...) do {} while (0)
  97 #endif
  98 #ifdef DEBUG_PROTO_E
  99 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
 100 #else
 101 #define TRACE_PE(fmt, arg...) do {} while (0)
 102 #endif
 103 #ifdef DEBUG_LDISC
 104 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
 105 #else
 106 #define TRACE_L(fmt, arg...) do {} while (0)
 107 #endif
 108 #ifdef DEBUG_QUEUE
 109 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
 110 #else
 111 #define TRACE_Q(fmt, arg...) do {} while (0)
 112 #endif
 113 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
 114 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
 115 static void put_char(struct r3964_info *pInfo, unsigned char ch);
 116 static void trigger_transmit(struct r3964_info *pInfo);
 117 static void retry_transmit(struct r3964_info *pInfo);
 118 static void transmit_block(struct r3964_info *pInfo);
 119 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
 120 static void receive_error(struct r3964_info *pInfo, const char flag);
 121 static void on_timeout(unsigned long priv);
 122 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
 123 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 124                 unsigned char __user * buf);
 125 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 126                 int error_code, struct r3964_block_header *pBlock);
 127 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 128                 struct r3964_client_info *pClient);
 129 static void remove_client_block(struct r3964_info *pInfo,
 130                 struct r3964_client_info *pClient);
 131
 132 static int r3964_open(struct tty_struct *tty);
 133 static void r3964_close(struct tty_struct *tty);
 134 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
 135                 unsigned char __user * buf, size_t nr);
 136 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
 137                 const unsigned char *buf, size_t nr);
 138 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
 139                 unsigned int cmd, unsigned long arg);
 140 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
 141 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
 142                 struct poll_table_struct *wait);
 143 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 144                 char *fp, int count);
 145
 146 static struct tty_ldisc tty_ldisc_N_R3964 = {
 147         .owner = THIS_MODULE,
 148         .magic = TTY_LDISC_MAGIC,
 149         .name = "R3964",
 150         .open = r3964_open,
 151         .close = r3964_close,
 152         .read = r3964_read,
 153         .write = r3964_write,
 154         .ioctl = r3964_ioctl,
 155         .set_termios = r3964_set_termios,
 156         .poll = r3964_poll,
 157         .receive_buf = r3964_receive_buf,
 158 };
 159
 160 static void dump_block(const unsigned char *block, unsigned int length)
 161 {
 162         unsigned int i, j;
 163         char linebuf[16 * 3 + 1];
 164
 165         for (i = 0; i < length; i += 16) {
 166                 for (j = 0; (j < 16) && (j + i < length); j++) {
 167                         sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
 168                 }
 169                 linebuf[3 * j] = '\0';
 170                 TRACE_PS("%s", linebuf);
 171         }
 172 }
 173
 174 /*************************************************************
 175  * Driver initialisation
 176  *************************************************************/
 177
 178 /*************************************************************
 179  * Module support routines
 180  *************************************************************/
 181
 182 static void __exit r3964_exit(void)
 183 {
 184         int status;
 185
 186         TRACE_M("cleanup_module()");
 187
 188         status = tty_unregister_ldisc(N_R3964);
 189
 190         if (status != 0) {
 191                 printk(KERN_ERR "r3964: error unregistering linediscipline: "
 192                                 "%d\n", status);
 193         } else {
 194                 TRACE_L("linediscipline successfully unregistered");
 195         }
 196 }
 197
 198 static int __init r3964_init(void)
 199 {
 200         int status;
 201
 202         printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
 203
 204         /*
 205          * Register the tty line discipline
 206          */
 207
 208         status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
 209         if (status == 0) {
 210                 TRACE_L("line discipline %d registered", N_R3964);
 211                 TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 212                         tty_ldisc_N_R3964.num);
 213                 TRACE_L("open=%p", tty_ldisc_N_R3964.open);
 214                 TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
 215         } else {
 216                 printk(KERN_ERR "r3964: error registering line discipline: "
 217                                 "%d\n", status);
 218         }
 219         return status;
 220 }
 221
 222 module_init(r3964_init);
 223 module_exit(r3964_exit);
 224
 225 /*************************************************************
 226  * Protocol implementation routines
 227  *************************************************************/
 228
 229 static void add_tx_queue(struct r3964_info *pInfo,
 230                          struct r3964_block_header *pHeader)
 231 {
 232         unsigned long flags;
 233
 234         spin_lock_irqsave(&pInfo->lock, flags);
 235
 236         pHeader->next = NULL;
 237
 238         if (pInfo->tx_last == NULL) {
 239                 pInfo->tx_first = pInfo->tx_last = pHeader;
 240         } else {
 241                 pInfo->tx_last->next = pHeader;
 242                 pInfo->tx_last = pHeader;
 243         }
 244
 245         spin_unlock_irqrestore(&pInfo->lock, flags);
 246
 247         TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
 248                 pHeader, pHeader->length, pInfo->tx_first);
 249 }
 250
 251 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 252 {
 253         struct r3964_block_header *pHeader;
 254         unsigned long flags;
 255 #ifdef DEBUG_QUEUE
 256         struct r3964_block_header *pDump;
 257 #endif
 258
 259         pHeader = pInfo->tx_first;
 260
 261         if (pHeader == NULL)
 262                 return;
 263
 264 #ifdef DEBUG_QUEUE
 265         printk("r3964: remove_from_tx_queue: %p, length %u - ",
 266                 pHeader, pHeader->length);
 267         for (pDump = pHeader; pDump; pDump = pDump->next)
 268                 printk("%p ", pDump);
 269         printk("\n");
 270 #endif
 271
 272         if (pHeader->owner) {
 273                 if (error_code) {
 274                         add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 275                                 error_code, NULL);
 276                 } else {
 277                         add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 278                                 error_code, NULL);
 279                 }
 280                 wake_up_interruptible(&pInfo->read_wait);
 281         }
 282
 283         spin_lock_irqsave(&pInfo->lock, flags);
 284
 285         pInfo->tx_first = pHeader->next;
 286         if (pInfo->tx_first == NULL) {
 287                 pInfo->tx_last = NULL;
 288         }
 289
 290         spin_unlock_irqrestore(&pInfo->lock, flags);
 291
 292         kfree(pHeader);
 293         TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
 294
 295         TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
 296                 pInfo->tx_first, pInfo->tx_last);
 297 }
 298
 299 static void add_rx_queue(struct r3964_info *pInfo,
 300                          struct r3964_block_header *pHeader)
 301 {
 302         unsigned long flags;
 303
 304         spin_lock_irqsave(&pInfo->lock, flags);
 305
 306         pHeader->next = NULL;
 307
 308         if (pInfo->rx_last == NULL) {
 309                 pInfo->rx_first = pInfo->rx_last = pHeader;
 310         } else {
 311                 pInfo->rx_last->next = pHeader;
 312                 pInfo->rx_last = pHeader;
 313         }
 314         pInfo->blocks_in_rx_queue++;
 315
 316         spin_unlock_irqrestore(&pInfo->lock, flags);
 317
 318         TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
 319                 pHeader, pHeader->length,
 320                 pInfo->rx_first, pInfo->blocks_in_rx_queue);
 321 }
 322
 323 static void remove_from_rx_queue(struct r3964_info *pInfo,
 324                                  struct r3964_block_header *pHeader)
 325 {
 326         unsigned long flags;
 327         struct r3964_block_header *pFind;
 328
 329         if (pHeader == NULL)
 330                 return;
 331
 332         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 333                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 334         TRACE_Q("remove_from_rx_queue: %p, length %u",
 335                 pHeader, pHeader->length);
 336
 337         spin_lock_irqsave(&pInfo->lock, flags);
 338
 339         if (pInfo->rx_first == pHeader) {
 340                 /* Remove the first block in the linked list: */
 341                 pInfo->rx_first = pHeader->next;
 342
 343                 if (pInfo->rx_first == NULL) {
 344                         pInfo->rx_last = NULL;
 345                 }
 346                 pInfo->blocks_in_rx_queue--;
 347         } else {
 348                 /* Find block to remove: */
 349                 for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
 350                         if (pFind->next == pHeader) {
 351                                 /* Got it. */
 352                                 pFind->next = pHeader->next;
 353                                 pInfo->blocks_in_rx_queue--;
 354                                 if (pFind->next == NULL) {
 355                                         /* Oh, removed the last one! */
 356                                         pInfo->rx_last = pFind;
 357                                 }
 358                                 break;
 359                         }
 360                 }
 361         }
 362
 363         spin_unlock_irqrestore(&pInfo->lock, flags);
 364
 365         kfree(pHeader);
 366         TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
 367
 368         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 369                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 370 }
 371
 372 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 373 {
 374         struct tty_struct *tty = pInfo->tty;
 375
 376         if (tty == NULL)
 377                 return;
 378
 379         if (tty->driver->put_char) {
 380                 tty->driver->put_char(tty, ch);
 381         }
 382         pInfo->bcc ^= ch;
 383 }
 384
 385 static void flush(struct r3964_info *pInfo)
 386 {
 387         struct tty_struct *tty = pInfo->tty;
 388
 389         if (tty == NULL)
 390                 return;
 391
 392         if (tty->driver->flush_chars) {
 393                 tty->driver->flush_chars(tty);
 394         }
 395 }
 396
 397 static void trigger_transmit(struct r3964_info *pInfo)
 398 {
 399         unsigned long flags;
 400
 401         spin_lock_irqsave(&pInfo->lock, flags);
 402
 403         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
 404                 pInfo->state = R3964_TX_REQUEST;
 405                 pInfo->nRetry = 0;
 406                 pInfo->flags &= ~R3964_ERROR;
 407                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 408
 409                 spin_unlock_irqrestore(&pInfo->lock, flags);
 410
 411                 TRACE_PS("trigger_transmit - sent STX");
 412
 413                 put_char(pInfo, STX);
 414                 flush(pInfo);
 415
 416                 pInfo->bcc = 0;
 417         } else {
 418                 spin_unlock_irqrestore(&pInfo->lock, flags);
 419         }
 420 }
 421
 422 static void retry_transmit(struct r3964_info *pInfo)
 423 {
 424         if (pInfo->nRetry < R3964_MAX_RETRIES) {
 425                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
 426                 pInfo->bcc = 0;
 427                 put_char(pInfo, STX);
 428                 flush(pInfo);
 429                 pInfo->state = R3964_TX_REQUEST;
 430                 pInfo->nRetry++;
 431                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 432         } else {
 433                 TRACE_PE("transmission failed after %d retries",
 434                          R3964_MAX_RETRIES);
 435
 436                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 437
 438                 put_char(pInfo, NAK);
 439                 flush(pInfo);
 440                 pInfo->state = R3964_IDLE;
 441
 442                 trigger_transmit(pInfo);
 443         }
 444 }
 445
 446 static void transmit_block(struct r3964_info *pInfo)
 447 {
 448         struct tty_struct *tty = pInfo->tty;
 449         struct r3964_block_header *pBlock = pInfo->tx_first;
 450         int room = 0;
 451
 452         if ((tty == NULL) || (pBlock == NULL)) {
 453                 return;
 454         }
 455
 456         if (tty->driver->write_room)
 457                 room = tty->driver->write_room(tty);
 458
 459         TRACE_PS("transmit_block %p, room %d, length %d",
 460                  pBlock, room, pBlock->length);
 461
 462         while (pInfo->tx_position < pBlock->length) {
 463                 if (room < 2)
 464                         break;
 465
 466                 if (pBlock->data[pInfo->tx_position] == DLE) {
 467                         /* send additional DLE char: */
 468                         put_char(pInfo, DLE);
 469                 }
 470                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 471
 472                 room--;
 473         }
 474
 475         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
 476                 put_char(pInfo, DLE);
 477                 put_char(pInfo, ETX);
 478                 if (pInfo->flags & R3964_BCC) {
 479                         put_char(pInfo, pInfo->bcc);
 480                 }
 481                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
 482                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 483         }
 484         flush(pInfo);
 485 }
 486
 487 static void on_receive_block(struct r3964_info *pInfo)
 488 {
 489         unsigned int length;
 490         struct r3964_client_info *pClient;
 491         struct r3964_block_header *pBlock;
 492
 493         length = pInfo->rx_position;
 494
 495         /* compare byte checksum characters: */
 496         if (pInfo->flags & R3964_BCC) {
 497                 if (pInfo->bcc != pInfo->last_rx) {
 498                         TRACE_PE("checksum error - got %x but expected %x",
 499                                  pInfo->last_rx, pInfo->bcc);
 500                         pInfo->flags |= R3964_CHECKSUM;
 501                 }
 502         }
 503
 504         /* check for errors (parity, overrun,...): */
 505         if (pInfo->flags & R3964_ERROR) {
 506                 TRACE_PE("on_receive_block - transmission failed error %x",
 507                          pInfo->flags & R3964_ERROR);
 508
 509                 put_char(pInfo, NAK);
 510                 flush(pInfo);
 511                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
 512                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
 513                         pInfo->nRetry++;
 514                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 515                 } else {
 516                         TRACE_PE("on_receive_block - failed after max retries");
 517                         pInfo->state = R3964_IDLE;
 518                 }
 519                 return;
 520         }
 521
 522         /* received block; submit DLE: */
 523         put_char(pInfo, DLE);
 524         flush(pInfo);
 525         del_timer_sync(&pInfo->tmr);
 526         TRACE_PS(" rx success: got %d chars", length);
 527
 528         /* prepare struct r3964_block_header: */
 529         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
 530                         GFP_KERNEL);
 531         TRACE_M("on_receive_block - kmalloc %p", pBlock);
 532
 533         if (pBlock == NULL)
 534                 return;
 535
 536         pBlock->length = length;
 537         pBlock->data = ((unsigned char *)pBlock) +
 538                         sizeof(struct r3964_block_header);
 539         pBlock->locks = 0;
 540         pBlock->next = NULL;
 541         pBlock->owner = NULL;
 542
 543         memcpy(pBlock->data, pInfo->rx_buf, length);
 544
 545         /* queue block into rx_queue: */
 546         add_rx_queue(pInfo, pBlock);
 547
 548         /* notify attached client processes: */
 549         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 550                 if (pClient->sig_flags & R3964_SIG_DATA) {
 551                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
 552                                 pBlock);
 553                 }
 554         }
 555         wake_up_interruptible(&pInfo->read_wait);
 556
 557         pInfo->state = R3964_IDLE;
 558
 559         trigger_transmit(pInfo);
 560 }
 561
 562 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 563 {
 564         switch (pInfo->state) {
 565         case R3964_TX_REQUEST:
 566                 if (c == DLE) {
 567                         TRACE_PS("TX_REQUEST - got DLE");
 568
 569                         pInfo->state = R3964_TRANSMITTING;
 570                         pInfo->tx_position = 0;
 571
 572                         transmit_block(pInfo);
 573                 } else if (c == STX) {
 574                         if (pInfo->nRetry == 0) {
 575                                 TRACE_PE("TX_REQUEST - init conflict");
 576                                 if (pInfo->priority == R3964_SLAVE) {
 577                                         goto start_receiving;
 578                                 }
 579                         } else {
 580                                 TRACE_PE("TX_REQUEST - secondary init "
 581                                         "conflict!? Switching to SLAVE mode "
 582                                         "for next rx.");
 583                                 goto start_receiving;
 584                         }
 585                 } else {
 586                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 587                         retry_transmit(pInfo);
 588                 }
 589                 break;
 590         case R3964_TRANSMITTING:
 591                 if (c == NAK) {
 592                         TRACE_PE("TRANSMITTING - got NAK");
 593                         retry_transmit(pInfo);
 594                 } else {
 595                         TRACE_PE("TRANSMITTING - got invalid char");
 596
 597                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 598                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 599                 }
 600                 break;
 601         case R3964_WAIT_FOR_TX_ACK:
 602                 if (c == DLE) {
 603                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 604                         remove_from_tx_queue(pInfo, R3964_OK);
 605
 606                         pInfo->state = R3964_IDLE;
 607                         trigger_transmit(pInfo);
 608                 } else {
 609                         retry_transmit(pInfo);
 610                 }
 611                 break;
 612         case R3964_WAIT_FOR_RX_REPEAT:
 613                 /* FALLTROUGH */
 614         case R3964_IDLE:
 615                 if (c == STX) {
 616                         /* Prevent rx_queue from overflow: */
 617                         if (pInfo->blocks_in_rx_queue >=
 618                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
 619                                 TRACE_PE("IDLE - got STX but no space in "
 620                                                 "rx_queue!");
 621                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
 622                                 mod_timer(&pInfo->tmr,
 623                                           jiffies + R3964_TO_NO_BUF);
 624                                 break;
 625                         }
 626 start_receiving:
 627                         /* Ok, start receiving: */
 628                         TRACE_PS("IDLE - got STX");
 629                         pInfo->rx_position = 0;
 630                         pInfo->last_rx = 0;
 631                         pInfo->flags &= ~R3964_ERROR;
 632                         pInfo->state = R3964_RECEIVING;
 633                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 634                         pInfo->nRetry = 0;
 635                         put_char(pInfo, DLE);
 636                         flush(pInfo);
 637                         pInfo->bcc = 0;
 638                 }
 639                 break;
 640         case R3964_RECEIVING:
 641                 if (pInfo->rx_position < RX_BUF_SIZE) {
 642                         pInfo->bcc ^= c;
 643
 644                         if (c == DLE) {
 645                                 if (pInfo->last_rx == DLE) {
 646                                         pInfo->last_rx = 0;
 647                                         goto char_to_buf;
 648                                 }
 649                                 pInfo->last_rx = DLE;
 650                                 break;
 651                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
 652                                 if (pInfo->flags & R3964_BCC) {
 653                                         pInfo->state = R3964_WAIT_FOR_BCC;
 654                                         mod_timer(&pInfo->tmr,
 655                                                   jiffies + R3964_TO_ZVZ);
 656                                 } else {
 657                                         on_receive_block(pInfo);
 658                                 }
 659                         } else {
 660                                 pInfo->last_rx = c;
 661 char_to_buf:
 662                                 pInfo->rx_buf[pInfo->rx_position++] = c;
 663                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 664                         }
 665                 }
 666                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 667                 break;
 668         case R3964_WAIT_FOR_BCC:
 669                 pInfo->last_rx = c;
 670                 on_receive_block(pInfo);
 671                 break;
 672         }
 673 }
 674
 675 static void receive_error(struct r3964_info *pInfo, const char flag)
 676 {
 677         switch (flag) {
 678         case TTY_NORMAL:
 679                 break;
 680         case TTY_BREAK:
 681                 TRACE_PE("received break");
 682                 pInfo->flags |= R3964_BREAK;
 683                 break;
 684         case TTY_PARITY:
 685                 TRACE_PE("parity error");
 686                 pInfo->flags |= R3964_PARITY;
 687                 break;
 688         case TTY_FRAME:
 689                 TRACE_PE("frame error");
 690                 pInfo->flags |= R3964_FRAME;
 691                 break;
 692         case TTY_OVERRUN:
 693                 TRACE_PE("frame overrun");
 694                 pInfo->flags |= R3964_OVERRUN;
 695                 break;
 696         default:
 697                 TRACE_PE("receive_error - unknown flag %d", flag);
 698                 pInfo->flags |= R3964_UNKNOWN;
 699                 break;
 700         }
 701 }
 702
 703 static void on_timeout(unsigned long priv)
 704 {
 705         struct r3964_info *pInfo = (void *)priv;
 706
 707         switch (pInfo->state) {
 708         case R3964_TX_REQUEST:
 709                 TRACE_PE("TX_REQUEST - timeout");
 710                 retry_transmit(pInfo);
 711                 break;
 712         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 713                 put_char(pInfo, NAK);
 714                 flush(pInfo);
 715                 retry_transmit(pInfo);
 716                 break;
 717         case R3964_WAIT_FOR_TX_ACK:
 718                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 719                 retry_transmit(pInfo);
 720                 break;
 721         case R3964_WAIT_FOR_RX_BUF:
 722                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 723                 put_char(pInfo, NAK);
 724                 flush(pInfo);
 725                 pInfo->state = R3964_IDLE;
 726                 break;
 727         case R3964_RECEIVING:
 728                 TRACE_PE("RECEIVING - timeout after %d chars",
 729                          pInfo->rx_position);
 730                 put_char(pInfo, NAK);
 731                 flush(pInfo);
 732                 pInfo->state = R3964_IDLE;
 733                 break;
 734         case R3964_WAIT_FOR_RX_REPEAT:
 735                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 736                 pInfo->state = R3964_IDLE;
 737                 break;
 738         case R3964_WAIT_FOR_BCC:
 739                 TRACE_PE("WAIT_FOR_BCC - timeout");
 740                 put_char(pInfo, NAK);
 741                 flush(pInfo);
 742                 pInfo->state = R3964_IDLE;
 743                 break;
 744         }
 745 }
 746
 747 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
 748                 struct pid *pid)
 749 {
 750         struct r3964_client_info *pClient;
 751
 752         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 753                 if (pClient->pid == pid) {
 754                         return pClient;
 755                 }
 756         }
 757         return NULL;
 758 }
 759
 760 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
 761 {
 762         struct r3964_client_info *pClient;
 763         struct r3964_client_info **ppClient;
 764         struct r3964_message *pMsg;
 765
 766         if ((arg & R3964_SIG_ALL) == 0) {
 767                 /* Remove client from client list */
 768                 for (ppClient = &pInfo->firstClient; *ppClient;
 769                      ppClient = &(*ppClient)->next) {
 770                         pClient = *ppClient;
 771
 772                         if (pClient->pid == pid) {
 773                                 TRACE_PS("removing client %d from client list",
 774                                          pid_nr(pid));
 775                                 *ppClient = pClient->next;
 776                                 while (pClient->msg_count) {
 777                                         pMsg = remove_msg(pInfo, pClient);
 778                                         if (pMsg) {
 779                                                 kfree(pMsg);
 780                                                 TRACE_M("enable_signals - msg "
 781                                                         "kfree %p", pMsg);
 782                                         }
 783                                 }
 784                                 put_pid(pClient->pid);
 785                                 kfree(pClient);
 786                                 TRACE_M("enable_signals - kfree %p", pClient);
 787                                 return 0;
 788                         }
 789                 }
 790                 return -EINVAL;
 791         } else {
 792                 pClient = findClient(pInfo, pid);
 793                 if (pClient) {
 794                         /* update signal options */
 795                         pClient->sig_flags = arg;
 796                 } else {
 797                         /* add client to client list */
 798                         pClient = kmalloc(sizeof(struct r3964_client_info),
 799                                         GFP_KERNEL);
 800                         TRACE_M("enable_signals - kmalloc %p", pClient);
 801                         if (pClient == NULL)
 802                                 return -ENOMEM;
 803
 804                         TRACE_PS("add client %d to client list", pid_nr(pid));
 805                         spin_lock_init(&pClient->lock);
 806                         pClient->sig_flags = arg;
 807                         pClient->pid = get_pid(pid);
 808                         pClient->next = pInfo->firstClient;
 809                         pClient->first_msg = NULL;
 810                         pClient->last_msg = NULL;
 811                         pClient->next_block_to_read = NULL;
 812                         pClient->msg_count = 0;
 813                         pInfo->firstClient = pClient;
 814                 }
 815         }
 816
 817         return 0;
 818 }
 819
 820 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 821                          unsigned char __user * buf)
 822 {
 823         struct r3964_client_info *pClient;
 824         struct r3964_block_header *block;
 825
 826         if (!buf) {
 827                 return -EINVAL;
 828         }
 829
 830         pClient = findClient(pInfo, pid);
 831         if (pClient == NULL) {
 832                 return -EINVAL;
 833         }
 834
 835         block = pClient->next_block_to_read;
 836         if (!block) {
 837                 return 0;
 838         } else {
 839                 if (copy_to_user(buf, block->data, block->length))
 840                         return -EFAULT;
 841
 842                 remove_client_block(pInfo, pClient);
 843                 return block->length;
 844         }
 845
 846         return -EINVAL;
 847 }
 848
 849 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 850                 int error_code, struct r3964_block_header *pBlock)
 851 {
 852         struct r3964_message *pMsg;
 853         unsigned long flags;
 854
 855         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
 856 queue_the_message:
 857
 858                 pMsg = kmalloc(sizeof(struct r3964_message),
 859                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
 860                 TRACE_M("add_msg - kmalloc %p", pMsg);
 861                 if (pMsg == NULL) {
 862                         return;
 863                 }
 864
 865                 spin_lock_irqsave(&pClient->lock, flags);
 866
 867                 pMsg->msg_id = msg_id;
 868                 pMsg->arg = arg;
 869                 pMsg->error_code = error_code;
 870                 pMsg->block = pBlock;
 871                 pMsg->next = NULL;
 872
 873                 if (pClient->last_msg == NULL) {
 874                         pClient->first_msg = pClient->last_msg = pMsg;
 875                 } else {
 876                         pClient->last_msg->next = pMsg;
 877                         pClient->last_msg = pMsg;
 878                 }
 879
 880                 pClient->msg_count++;
 881
 882                 if (pBlock != NULL) {
 883                         pBlock->locks++;
 884                 }
 885                 spin_unlock_irqrestore(&pClient->lock, flags);
 886         } else {
 887                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
 888                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
 889                         pClient->last_msg->arg++;
 890                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 891                 } else {
 892                         msg_id = R3964_MSG_ACK;
 893                         arg = 0;
 894                         error_code = R3964_OVERFLOW;
 895                         pBlock = NULL;
 896                         TRACE_PE("add_msg - queue OVERFLOW-msg");
 897                         goto queue_the_message;
 898                 }
 899         }
 900         /* Send SIGIO signal to client process: */
 901         if (pClient->sig_flags & R3964_USE_SIGIO) {
 902                 kill_pid(pClient->pid, SIGIO, 1);
 903         }
 904 }
 905
 906 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 907                                         struct r3964_client_info *pClient)
 908 {
 909         struct r3964_message *pMsg = NULL;
 910         unsigned long flags;
 911
 912         if (pClient->first_msg) {
 913                 spin_lock_irqsave(&pClient->lock, flags);
 914
 915                 pMsg = pClient->first_msg;
 916                 pClient->first_msg = pMsg->next;
 917                 if (pClient->first_msg == NULL) {
 918                         pClient->last_msg = NULL;
 919                 }
 920
 921                 pClient->msg_count--;
 922                 if (pMsg->block) {
 923                         remove_client_block(pInfo, pClient);
 924                         pClient->next_block_to_read = pMsg->block;
 925                 }
 926                 spin_unlock_irqrestore(&pClient->lock, flags);
 927         }
 928         return pMsg;
 929 }
 930
 931 static void remove_client_block(struct r3964_info *pInfo,
 932                                 struct r3964_client_info *pClient)
 933 {
 934         struct r3964_block_header *block;
 935
 936         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
 937
 938         block = pClient->next_block_to_read;
 939         if (block) {
 940                 block->locks--;
 941                 if (block->locks == 0) {
 942                         remove_from_rx_queue(pInfo, block);
 943                 }
 944         }
 945         pClient->next_block_to_read = NULL;
 946 }
 947
 948 /*************************************************************
 949  * Line discipline routines
 950  *************************************************************/
 951
 952 static int r3964_open(struct tty_struct *tty)
 953 {
 954         struct r3964_info *pInfo;
 955
 956         TRACE_L("open");
 957         TRACE_L("tty=%p, PID=%d, disc_data=%p",
 958                 tty, current->pid, tty->disc_data);
 959
 960         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
 961         TRACE_M("r3964_open - info kmalloc %p", pInfo);
 962
 963         if (!pInfo) {
 964                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
 965                 return -ENOMEM;
 966         }
 967
 968         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
 969         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
 970
 971         if (!pInfo->rx_buf) {
 972                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
 973                 kfree(pInfo);
 974                 TRACE_M("r3964_open - info kfree %p", pInfo);
 975                 return -ENOMEM;
 976         }
 977
 978         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
 979         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
 980
 981         if (!pInfo->tx_buf) {
 982                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
 983                 kfree(pInfo->rx_buf);
 984                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
 985                 kfree(pInfo);
 986                 TRACE_M("r3964_open - info kfree %p", pInfo);
 987                 return -ENOMEM;
 988         }
 989
 990         spin_lock_init(&pInfo->lock);
 991         pInfo->tty = tty;
 992         init_waitqueue_head(&pInfo->read_wait);
 993         pInfo->priority = R3964_MASTER;
 994         pInfo->rx_first = pInfo->rx_last = NULL;
 995         pInfo->tx_first = pInfo->tx_last = NULL;
 996         pInfo->rx_position = 0;
 997         pInfo->tx_position = 0;
 998         pInfo->last_rx = 0;
 999         pInfo->blocks_in_rx_queue = 0;
1000         pInfo->firstClient = NULL;
1001         pInfo->state = R3964_IDLE;
1002         pInfo->flags = R3964_DEBUG;
1003         pInfo->nRetry = 0;
1004
1005         tty->disc_data = pInfo;
1006         tty->receive_room = 65536;
1007
1008         init_timer(&pInfo->tmr);
1009         pInfo->tmr.data = (unsigned long)pInfo;
1010         pInfo->tmr.function = on_timeout;
1011
1012         return 0;
1013 }
1014
1015 static void r3964_close(struct tty_struct *tty)
1016 {
1017         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1018         struct r3964_client_info *pClient, *pNext;
1019         struct r3964_message *pMsg;
1020         struct r3964_block_header *pHeader, *pNextHeader;
1021         unsigned long flags;
1022
1023         TRACE_L("close");
1024
1025         /*
1026          * Make sure that our task queue isn't activated.  If it
1027          * is, take it out of the linked list.
1028          */
1029         del_timer_sync(&pInfo->tmr);
1030
1031         /* Remove client-structs and message queues: */
1032         pClient = pInfo->firstClient;
1033         while (pClient) {
1034                 pNext = pClient->next;
1035                 while (pClient->msg_count) {
1036                         pMsg = remove_msg(pInfo, pClient);
1037                         if (pMsg) {
1038                                 kfree(pMsg);
1039                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1040                         }
1041                 }
1042                 put_pid(pClient->pid);
1043                 kfree(pClient);
1044                 TRACE_M("r3964_close - client kfree %p", pClient);
1045                 pClient = pNext;
1046         }
1047         /* Remove jobs from tx_queue: */
1048         spin_lock_irqsave(&pInfo->lock, flags);
1049         pHeader = pInfo->tx_first;
1050         pInfo->tx_first = pInfo->tx_last = NULL;
1051         spin_unlock_irqrestore(&pInfo->lock, flags);
1052
1053         while (pHeader) {
1054                 pNextHeader = pHeader->next;
1055                 kfree(pHeader);
1056                 pHeader = pNextHeader;
1057         }
1058
1059         /* Free buffers: */
1060         wake_up_interruptible(&pInfo->read_wait);
1061         kfree(pInfo->rx_buf);
1062         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1063         kfree(pInfo->tx_buf);
1064         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1065         kfree(pInfo);
1066         TRACE_M("r3964_close - info kfree %p", pInfo);
1067 }
1068
1069 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1070                           unsigned char __user * buf, size_t nr)
1071 {
1072         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1073         struct r3964_client_info *pClient;
1074         struct r3964_message *pMsg;
1075         struct r3964_client_message theMsg;
1076         DECLARE_WAITQUEUE(wait, current);
1077
1078         int count;
1079
1080         TRACE_L("read()");
1081
1082         pClient = findClient(pInfo, task_pid(current));
1083         if (pClient) {
1084                 pMsg = remove_msg(pInfo, pClient);
1085                 if (pMsg == NULL) {
1086                         /* no messages available. */
1087                         if (file->f_flags & O_NONBLOCK) {
1088                                 return -EAGAIN;
1089                         }
1090                         /* block until there is a message: */
1091                         add_wait_queue(&pInfo->read_wait, &wait);
1092 repeat:
1093                         current->state = TASK_INTERRUPTIBLE;
1094                         pMsg = remove_msg(pInfo, pClient);
1095                         if (!pMsg && !signal_pending(current)) {
1096                                 schedule();
1097                                 goto repeat;
1098                         }
1099                         current->state = TASK_RUNNING;
1100                         remove_wait_queue(&pInfo->read_wait, &wait);
1101                 }
1102
1103                 /* If we still haven't got a message, we must have been signalled */
1104
1105                 if (!pMsg)
1106                         return -EINTR;
1107
1108                 /* deliver msg to client process: */
1109                 theMsg.msg_id = pMsg->msg_id;
1110                 theMsg.arg = pMsg->arg;
1111                 theMsg.error_code = pMsg->error_code;
1112                 count = sizeof(struct r3964_client_message);
1113
1114                 kfree(pMsg);
1115                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1116
1117                 if (copy_to_user(buf, &theMsg, count))
1118                         return -EFAULT;
1119
1120                 TRACE_PS("read - return %d", count);
1121                 return count;
1122         }
1123         return -EPERM;
1124 }
1125
1126 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1127                            const unsigned char *data, size_t count)
1128 {
1129         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1130         struct r3964_block_header *pHeader;
1131         struct r3964_client_info *pClient;
1132         unsigned char *new_data;
1133
1134         TRACE_L("write request, %d characters", count);
1135 /*
1136  * Verify the pointers
1137  */
1138
1139         if (!pInfo)
1140                 return -EIO;
1141
1142 /*
1143  * Ensure that the caller does not wish to send too much.
1144  */
1145         if (count > R3964_MTU) {
1146                 if (pInfo->flags & R3964_DEBUG) {
1147                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1148                                 "packet from %u to mtu %d", count, R3964_MTU);
1149                 }
1150                 count = R3964_MTU;
1151         }
1152 /*
1153  * Allocate a buffer for the data and copy it from the buffer with header prepended
1154  */
1155         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1156                         GFP_KERNEL);
1157         TRACE_M("r3964_write - kmalloc %p", new_data);
1158         if (new_data == NULL) {
1159                 if (pInfo->flags & R3964_DEBUG) {
1160                         printk(KERN_ERR "r3964_write: no memory\n");
1161                 }
1162                 return -ENOSPC;
1163         }
1164
1165         pHeader = (struct r3964_block_header *)new_data;
1166         pHeader->data = new_data + sizeof(struct r3964_block_header);
1167         pHeader->length = count;
1168         pHeader->locks = 0;
1169         pHeader->owner = NULL;
1170
1171         pClient = findClient(pInfo, task_pid(current));
1172         if (pClient) {
1173                 pHeader->owner = pClient;
1174         }
1175
1176         memcpy(pHeader->data, data, count);     /* We already verified this */
1177
1178         if (pInfo->flags & R3964_DEBUG) {
1179                 dump_block(pHeader->data, count);
1180         }
1181
1182 /*
1183  * Add buffer to transmit-queue:
1184  */
1185         add_tx_queue(pInfo, pHeader);
1186         trigger_transmit(pInfo);
1187
1188         return 0;
1189 }
1190
1191 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1192                 unsigned int cmd, unsigned long arg)
1193 {
1194         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1195         if (pInfo == NULL)
1196                 return -EINVAL;
1197         switch (cmd) {
1198         case R3964_ENABLE_SIGNALS:
1199                 return enable_signals(pInfo, task_pid(current), arg);
1200         case R3964_SETPRIORITY:
1201                 if (arg < R3964_MASTER || arg > R3964_SLAVE)
1202                         return -EINVAL;
1203                 pInfo->priority = arg & 0xff;
1204                 return 0;
1205         case R3964_USE_BCC:
1206                 if (arg)
1207                         pInfo->flags |= R3964_BCC;
1208                 else
1209                         pInfo->flags &= ~R3964_BCC;
1210                 return 0;
1211         case R3964_READ_TELEGRAM:
1212                 return read_telegram(pInfo, task_pid(current),
1213                                 (unsigned char __user *)arg);
1214         default:
1215                 return -ENOIOCTLCMD;
1216         }
1217 }
1218
1219 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1220 {
1221         TRACE_L("set_termios");
1222 }
1223
1224 /* Called without the kernel lock held - fine */
1225 static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1226                         struct poll_table_struct *wait)
1227 {
1228         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1229         struct r3964_client_info *pClient;
1230         struct r3964_message *pMsg = NULL;
1231         unsigned long flags;
1232         int result = POLLOUT;
1233
1234         TRACE_L("POLL");
1235
1236         pClient = findClient(pInfo, task_pid(current));
1237         if (pClient) {
1238                 poll_wait(file, &pInfo->read_wait, wait);
1239                 spin_lock_irqsave(&pInfo->lock, flags);
1240                 pMsg = pClient->first_msg;
1241                 spin_unlock_irqrestore(&pInfo->lock, flags);
1242                 if (pMsg)
1243                         result |= POLLIN | POLLRDNORM;
1244         } else {
1245                 result = -EINVAL;
1246         }
1247         return result;
1248 }
1249
1250 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1251                         char *fp, int count)
1252 {
1253         struct r3964_info *pInfo = (struct r3964_info *)tty->disc_data;
1254         const unsigned char *p;
1255         char *f, flags = 0;
1256         int i;
1257
1258         for (i = count, p = cp, f = fp; i; i--, p++) {
1259                 if (f)
1260                         flags = *f++;
1261                 if (flags == TTY_NORMAL) {
1262                         receive_char(pInfo, *p);
1263                 } else {
1264                         receive_error(pInfo, flags);
1265                 }
1266
1267         }
1268 }
1269
1270 MODULE_LICENSE("GPL");
1271 MODULE_ALIAS_LDISC(N_R3964);