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