drivers/tty/n_r3964.c

   1 // SPDX-License-Identifier: GPL-1.0+
   2 /* r3964 linediscipline for linux
   3  *
   4  * -----------------------------------------------------------
   5  * Copyright by
   6  * Philips Automation Projects
   7  * Kassel (Germany)
   8  * -----------------------------------------------------------
   9  * Author:
  10  * L. Haag
  11  *
  12  * $Log: n_r3964.c,v $
  13  * Revision 1.10  2001/03/18 13:02:24  dwmw2
  14  * Fix timer usage, use spinlocks properly.
  15  *
  16  * Revision 1.9  2001/03/18 12:52:14  dwmw2
  17  * Merge changes in 2.4.2
  18  *
  19  * Revision 1.8  2000/03/23 14:14:54  dwmw2
  20  * Fix race in sleeping in r3964_read()
  21  *
  22  * Revision 1.7  1999/28/08 11:41:50  dwmw2
  23  * Port to 2.3 kernel
  24  *
  25  * Revision 1.6  1998/09/30 00:40:40  dwmw2
  26  * Fixed compilation on 2.0.x kernels
  27  * Updated to newly registered tty-ldisc number 9
  28  *
  29  * Revision 1.5  1998/09/04 21:57:36  dwmw2
  30  * Signal handling bug fixes, port to 2.1.x.
  31  *
  32  * Revision 1.4  1998/04/02 20:26:59  lhaag
  33  * select, blocking, ...
  34  *
  35  * Revision 1.3  1998/02/12 18:58:43  root
  36  * fixed some memory leaks
  37  * calculation of checksum characters
  38  *
  39  * Revision 1.2  1998/02/07 13:03:34  root
  40  * ioctl read_telegram
  41  *
  42  * Revision 1.1  1998/02/06 19:21:03  root
  43  * Initial revision
  44  *
  45  *
  46  */
  47
  48 #include <linux/module.h>
  49 #include <linux/kernel.h>
  50 #include <linux/sched.h>
  51 #include <linux/types.h>
  52 #include <linux/fcntl.h>
  53 #include <linux/interrupt.h>
  54 #include <linux/ptrace.h>
  55 #include <linux/ioport.h>
  56 #include <linux/in.h>
  57 #include <linux/slab.h>
  58 #include <linux/tty.h>
  59 #include <linux/errno.h>
  60 #include <linux/string.h>       /* used in new tty drivers */
  61 #include <linux/signal.h>       /* used in new tty drivers */
  62 #include <linux/ioctl.h>
  63 #include <linux/n_r3964.h>
  64 #include <linux/poll.h>
  65 #include <linux/init.h>
  66 #include <linux/uaccess.h>
  67
  68 /*#define DEBUG_QUEUE*/
  69
  70 /* Log successful handshake and protocol operations  */
  71 /*#define DEBUG_PROTO_S*/
  72
  73 /* Log handshake and protocol errors: */
  74 /*#define DEBUG_PROTO_E*/
  75
  76 /* Log Linediscipline operations (open, close, read, write...): */
  77 /*#define DEBUG_LDISC*/
  78
  79 /* Log module and memory operations (init, cleanup; kmalloc, kfree): */
  80 /*#define DEBUG_MODUL*/
  81
  82 /* Macro helpers for debug output: */
  83 #define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
  84
  85 #ifdef DEBUG_MODUL
  86 #define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
  87 #else
  88 #define TRACE_M(fmt, arg...) do {} while (0)
  89 #endif
  90 #ifdef DEBUG_PROTO_S
  91 #define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
  92 #else
  93 #define TRACE_PS(fmt, arg...) do {} while (0)
  94 #endif
  95 #ifdef DEBUG_PROTO_E
  96 #define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
  97 #else
  98 #define TRACE_PE(fmt, arg...) do {} while (0)
  99 #endif
 100 #ifdef DEBUG_LDISC
 101 #define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
 102 #else
 103 #define TRACE_L(fmt, arg...) do {} while (0)
 104 #endif
 105 #ifdef DEBUG_QUEUE
 106 #define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
 107 #else
 108 #define TRACE_Q(fmt, arg...) do {} while (0)
 109 #endif
 110 static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
 111 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
 112 static void put_char(struct r3964_info *pInfo, unsigned char ch);
 113 static void trigger_transmit(struct r3964_info *pInfo);
 114 static void retry_transmit(struct r3964_info *pInfo);
 115 static void transmit_block(struct r3964_info *pInfo);
 116 static void receive_char(struct r3964_info *pInfo, const unsigned char c);
 117 static void receive_error(struct r3964_info *pInfo, const char flag);
 118 static void on_timeout(struct timer_list *t);
 119 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
 120 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 121                 unsigned char __user * buf);
 122 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 123                 int error_code, struct r3964_block_header *pBlock);
 124 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 125                 struct r3964_client_info *pClient);
 126 static void remove_client_block(struct r3964_info *pInfo,
 127                 struct r3964_client_info *pClient);
 128
 129 static int r3964_open(struct tty_struct *tty);
 130 static void r3964_close(struct tty_struct *tty);
 131 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
 132                 unsigned char __user * buf, size_t nr);
 133 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
 134                 const unsigned char *buf, size_t nr);
 135 static int r3964_ioctl(struct tty_struct *tty, struct file *file,
 136                 unsigned int cmd, unsigned long arg);
 137 static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
 138 static __poll_t r3964_poll(struct tty_struct *tty, struct file *file,
 139                 struct poll_table_struct *wait);
 140 static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 141                 char *fp, int count);
 142
 143 static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
 144         .owner = THIS_MODULE,
 145         .magic = TTY_LDISC_MAGIC,
 146         .name = "R3964",
 147         .open = r3964_open,
 148         .close = r3964_close,
 149         .read = r3964_read,
 150         .write = r3964_write,
 151         .ioctl = r3964_ioctl,
 152         .set_termios = r3964_set_termios,
 153         .poll = r3964_poll,
 154         .receive_buf = r3964_receive_buf,
 155 };
 156
 157 static void dump_block(const unsigned char *block, unsigned int length)
 158 {
 159         unsigned int i, j;
 160         char linebuf[16 * 3 + 1];
 161
 162         for (i = 0; i < length; i += 16) {
 163                 for (j = 0; (j < 16) && (j + i < length); j++) {
 164                         sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
 165                 }
 166                 linebuf[3 * j] = '\0';
 167                 TRACE_PS("%s", linebuf);
 168         }
 169 }
 170
 171 /*************************************************************
 172  * Driver initialisation
 173  *************************************************************/
 174
 175 /*************************************************************
 176  * Module support routines
 177  *************************************************************/
 178
 179 static void __exit r3964_exit(void)
 180 {
 181         int status;
 182
 183         TRACE_M("cleanup_module()");
 184
 185         status = tty_unregister_ldisc(N_R3964);
 186
 187         if (status != 0) {
 188                 printk(KERN_ERR "r3964: error unregistering linediscipline: "
 189                                 "%d\n", status);
 190         } else {
 191                 TRACE_L("linediscipline successfully unregistered");
 192         }
 193 }
 194
 195 static int __init r3964_init(void)
 196 {
 197         int status;
 198
 199         printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
 200
 201         /*
 202          * Register the tty line discipline
 203          */
 204
 205         status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
 206         if (status == 0) {
 207                 TRACE_L("line discipline %d registered", N_R3964);
 208                 TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
 209                         tty_ldisc_N_R3964.num);
 210                 TRACE_L("open=%p", tty_ldisc_N_R3964.open);
 211                 TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
 212         } else {
 213                 printk(KERN_ERR "r3964: error registering line discipline: "
 214                                 "%d\n", status);
 215         }
 216         return status;
 217 }
 218
 219 module_init(r3964_init);
 220 module_exit(r3964_exit);
 221
 222 /*************************************************************
 223  * Protocol implementation routines
 224  *************************************************************/
 225
 226 static void add_tx_queue(struct r3964_info *pInfo,
 227                          struct r3964_block_header *pHeader)
 228 {
 229         unsigned long flags;
 230
 231         spin_lock_irqsave(&pInfo->lock, flags);
 232
 233         pHeader->next = NULL;
 234
 235         if (pInfo->tx_last == NULL) {
 236                 pInfo->tx_first = pInfo->tx_last = pHeader;
 237         } else {
 238                 pInfo->tx_last->next = pHeader;
 239                 pInfo->tx_last = pHeader;
 240         }
 241
 242         spin_unlock_irqrestore(&pInfo->lock, flags);
 243
 244         TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
 245                 pHeader, pHeader->length, pInfo->tx_first);
 246 }
 247
 248 static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
 249 {
 250         struct r3964_block_header *pHeader;
 251         unsigned long flags;
 252 #ifdef DEBUG_QUEUE
 253         struct r3964_block_header *pDump;
 254 #endif
 255
 256         pHeader = pInfo->tx_first;
 257
 258         if (pHeader == NULL)
 259                 return;
 260
 261 #ifdef DEBUG_QUEUE
 262         printk("r3964: remove_from_tx_queue: %p, length %u - ",
 263                 pHeader, pHeader->length);
 264         for (pDump = pHeader; pDump; pDump = pDump->next)
 265                 printk("%p ", pDump);
 266         printk("\n");
 267 #endif
 268
 269         if (pHeader->owner) {
 270                 if (error_code) {
 271                         add_msg(pHeader->owner, R3964_MSG_ACK, 0,
 272                                 error_code, NULL);
 273                 } else {
 274                         add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
 275                                 error_code, NULL);
 276                 }
 277                 wake_up_interruptible(&pInfo->tty->read_wait);
 278         }
 279
 280         spin_lock_irqsave(&pInfo->lock, flags);
 281
 282         pInfo->tx_first = pHeader->next;
 283         if (pInfo->tx_first == NULL) {
 284                 pInfo->tx_last = NULL;
 285         }
 286
 287         spin_unlock_irqrestore(&pInfo->lock, flags);
 288
 289         kfree(pHeader);
 290         TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
 291
 292         TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
 293                 pInfo->tx_first, pInfo->tx_last);
 294 }
 295
 296 static void add_rx_queue(struct r3964_info *pInfo,
 297                          struct r3964_block_header *pHeader)
 298 {
 299         unsigned long flags;
 300
 301         spin_lock_irqsave(&pInfo->lock, flags);
 302
 303         pHeader->next = NULL;
 304
 305         if (pInfo->rx_last == NULL) {
 306                 pInfo->rx_first = pInfo->rx_last = pHeader;
 307         } else {
 308                 pInfo->rx_last->next = pHeader;
 309                 pInfo->rx_last = pHeader;
 310         }
 311         pInfo->blocks_in_rx_queue++;
 312
 313         spin_unlock_irqrestore(&pInfo->lock, flags);
 314
 315         TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
 316                 pHeader, pHeader->length,
 317                 pInfo->rx_first, pInfo->blocks_in_rx_queue);
 318 }
 319
 320 static void remove_from_rx_queue(struct r3964_info *pInfo,
 321                                  struct r3964_block_header *pHeader)
 322 {
 323         unsigned long flags;
 324         struct r3964_block_header *pFind;
 325
 326         if (pHeader == NULL)
 327                 return;
 328
 329         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 330                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 331         TRACE_Q("remove_from_rx_queue: %p, length %u",
 332                 pHeader, pHeader->length);
 333
 334         spin_lock_irqsave(&pInfo->lock, flags);
 335
 336         if (pInfo->rx_first == pHeader) {
 337                 /* Remove the first block in the linked list: */
 338                 pInfo->rx_first = pHeader->next;
 339
 340                 if (pInfo->rx_first == NULL) {
 341                         pInfo->rx_last = NULL;
 342                 }
 343                 pInfo->blocks_in_rx_queue--;
 344         } else {
 345                 /* Find block to remove: */
 346                 for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
 347                         if (pFind->next == pHeader) {
 348                                 /* Got it. */
 349                                 pFind->next = pHeader->next;
 350                                 pInfo->blocks_in_rx_queue--;
 351                                 if (pFind->next == NULL) {
 352                                         /* Oh, removed the last one! */
 353                                         pInfo->rx_last = pFind;
 354                                 }
 355                                 break;
 356                         }
 357                 }
 358         }
 359
 360         spin_unlock_irqrestore(&pInfo->lock, flags);
 361
 362         kfree(pHeader);
 363         TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
 364
 365         TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
 366                 pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
 367 }
 368
 369 static void put_char(struct r3964_info *pInfo, unsigned char ch)
 370 {
 371         struct tty_struct *tty = pInfo->tty;
 372         /* FIXME: put_char should not be called from an IRQ */
 373         tty_put_char(tty, ch);
 374         pInfo->bcc ^= ch;
 375 }
 376
 377 static void flush(struct r3964_info *pInfo)
 378 {
 379         struct tty_struct *tty = pInfo->tty;
 380
 381         if (tty == NULL || tty->ops->flush_chars == NULL)
 382                 return;
 383         tty->ops->flush_chars(tty);
 384 }
 385
 386 static void trigger_transmit(struct r3964_info *pInfo)
 387 {
 388         unsigned long flags;
 389
 390         spin_lock_irqsave(&pInfo->lock, flags);
 391
 392         if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
 393                 pInfo->state = R3964_TX_REQUEST;
 394                 pInfo->nRetry = 0;
 395                 pInfo->flags &= ~R3964_ERROR;
 396                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 397
 398                 spin_unlock_irqrestore(&pInfo->lock, flags);
 399
 400                 TRACE_PS("trigger_transmit - sent STX");
 401
 402                 put_char(pInfo, STX);
 403                 flush(pInfo);
 404
 405                 pInfo->bcc = 0;
 406         } else {
 407                 spin_unlock_irqrestore(&pInfo->lock, flags);
 408         }
 409 }
 410
 411 static void retry_transmit(struct r3964_info *pInfo)
 412 {
 413         if (pInfo->nRetry < R3964_MAX_RETRIES) {
 414                 TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
 415                 pInfo->bcc = 0;
 416                 put_char(pInfo, STX);
 417                 flush(pInfo);
 418                 pInfo->state = R3964_TX_REQUEST;
 419                 pInfo->nRetry++;
 420                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 421         } else {
 422                 TRACE_PE("transmission failed after %d retries",
 423                          R3964_MAX_RETRIES);
 424
 425                 remove_from_tx_queue(pInfo, R3964_TX_FAIL);
 426
 427                 put_char(pInfo, NAK);
 428                 flush(pInfo);
 429                 pInfo->state = R3964_IDLE;
 430
 431                 trigger_transmit(pInfo);
 432         }
 433 }
 434
 435 static void transmit_block(struct r3964_info *pInfo)
 436 {
 437         struct tty_struct *tty = pInfo->tty;
 438         struct r3964_block_header *pBlock = pInfo->tx_first;
 439         int room = 0;
 440
 441         if (tty == NULL || pBlock == NULL) {
 442                 return;
 443         }
 444
 445         room = tty_write_room(tty);
 446
 447         TRACE_PS("transmit_block %p, room %d, length %d",
 448                  pBlock, room, pBlock->length);
 449
 450         while (pInfo->tx_position < pBlock->length) {
 451                 if (room < 2)
 452                         break;
 453
 454                 if (pBlock->data[pInfo->tx_position] == DLE) {
 455                         /* send additional DLE char: */
 456                         put_char(pInfo, DLE);
 457                 }
 458                 put_char(pInfo, pBlock->data[pInfo->tx_position++]);
 459
 460                 room--;
 461         }
 462
 463         if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
 464                 put_char(pInfo, DLE);
 465                 put_char(pInfo, ETX);
 466                 if (pInfo->flags & R3964_BCC) {
 467                         put_char(pInfo, pInfo->bcc);
 468                 }
 469                 pInfo->state = R3964_WAIT_FOR_TX_ACK;
 470                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
 471         }
 472         flush(pInfo);
 473 }
 474
 475 static void on_receive_block(struct r3964_info *pInfo)
 476 {
 477         unsigned int length;
 478         struct r3964_client_info *pClient;
 479         struct r3964_block_header *pBlock;
 480
 481         length = pInfo->rx_position;
 482
 483         /* compare byte checksum characters: */
 484         if (pInfo->flags & R3964_BCC) {
 485                 if (pInfo->bcc != pInfo->last_rx) {
 486                         TRACE_PE("checksum error - got %x but expected %x",
 487                                  pInfo->last_rx, pInfo->bcc);
 488                         pInfo->flags |= R3964_CHECKSUM;
 489                 }
 490         }
 491
 492         /* check for errors (parity, overrun,...): */
 493         if (pInfo->flags & R3964_ERROR) {
 494                 TRACE_PE("on_receive_block - transmission failed error %x",
 495                          pInfo->flags & R3964_ERROR);
 496
 497                 put_char(pInfo, NAK);
 498                 flush(pInfo);
 499                 if (pInfo->nRetry < R3964_MAX_RETRIES) {
 500                         pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
 501                         pInfo->nRetry++;
 502                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
 503                 } else {
 504                         TRACE_PE("on_receive_block - failed after max retries");
 505                         pInfo->state = R3964_IDLE;
 506                 }
 507                 return;
 508         }
 509
 510         /* received block; submit DLE: */
 511         put_char(pInfo, DLE);
 512         flush(pInfo);
 513         del_timer_sync(&pInfo->tmr);
 514         TRACE_PS(" rx success: got %d chars", length);
 515
 516         /* prepare struct r3964_block_header: */
 517         pBlock = kmalloc(length + sizeof(struct r3964_block_header),
 518                         GFP_KERNEL);
 519         TRACE_M("on_receive_block - kmalloc %p", pBlock);
 520
 521         if (pBlock == NULL)
 522                 return;
 523
 524         pBlock->length = length;
 525         pBlock->data = ((unsigned char *)pBlock) +
 526                         sizeof(struct r3964_block_header);
 527         pBlock->locks = 0;
 528         pBlock->next = NULL;
 529         pBlock->owner = NULL;
 530
 531         memcpy(pBlock->data, pInfo->rx_buf, length);
 532
 533         /* queue block into rx_queue: */
 534         add_rx_queue(pInfo, pBlock);
 535
 536         /* notify attached client processes: */
 537         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 538                 if (pClient->sig_flags & R3964_SIG_DATA) {
 539                         add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
 540                                 pBlock);
 541                 }
 542         }
 543         wake_up_interruptible(&pInfo->tty->read_wait);
 544
 545         pInfo->state = R3964_IDLE;
 546
 547         trigger_transmit(pInfo);
 548 }
 549
 550 static void receive_char(struct r3964_info *pInfo, const unsigned char c)
 551 {
 552         switch (pInfo->state) {
 553         case R3964_TX_REQUEST:
 554                 if (c == DLE) {
 555                         TRACE_PS("TX_REQUEST - got DLE");
 556
 557                         pInfo->state = R3964_TRANSMITTING;
 558                         pInfo->tx_position = 0;
 559
 560                         transmit_block(pInfo);
 561                 } else if (c == STX) {
 562                         if (pInfo->nRetry == 0) {
 563                                 TRACE_PE("TX_REQUEST - init conflict");
 564                                 if (pInfo->priority == R3964_SLAVE) {
 565                                         goto start_receiving;
 566                                 }
 567                         } else {
 568                                 TRACE_PE("TX_REQUEST - secondary init "
 569                                         "conflict!? Switching to SLAVE mode "
 570                                         "for next rx.");
 571                                 goto start_receiving;
 572                         }
 573                 } else {
 574                         TRACE_PE("TX_REQUEST - char != DLE: %x", c);
 575                         retry_transmit(pInfo);
 576                 }
 577                 break;
 578         case R3964_TRANSMITTING:
 579                 if (c == NAK) {
 580                         TRACE_PE("TRANSMITTING - got NAK");
 581                         retry_transmit(pInfo);
 582                 } else {
 583                         TRACE_PE("TRANSMITTING - got invalid char");
 584
 585                         pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
 586                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 587                 }
 588                 break;
 589         case R3964_WAIT_FOR_TX_ACK:
 590                 if (c == DLE) {
 591                         TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
 592                         remove_from_tx_queue(pInfo, R3964_OK);
 593
 594                         pInfo->state = R3964_IDLE;
 595                         trigger_transmit(pInfo);
 596                 } else {
 597                         retry_transmit(pInfo);
 598                 }
 599                 break;
 600         case R3964_WAIT_FOR_RX_REPEAT:
 601                 /* FALLTHROUGH */
 602         case R3964_IDLE:
 603                 if (c == STX) {
 604                         /* Prevent rx_queue from overflow: */
 605                         if (pInfo->blocks_in_rx_queue >=
 606                             R3964_MAX_BLOCKS_IN_RX_QUEUE) {
 607                                 TRACE_PE("IDLE - got STX but no space in "
 608                                                 "rx_queue!");
 609                                 pInfo->state = R3964_WAIT_FOR_RX_BUF;
 610                                 mod_timer(&pInfo->tmr,
 611                                           jiffies + R3964_TO_NO_BUF);
 612                                 break;
 613                         }
 614 start_receiving:
 615                         /* Ok, start receiving: */
 616                         TRACE_PS("IDLE - got STX");
 617                         pInfo->rx_position = 0;
 618                         pInfo->last_rx = 0;
 619                         pInfo->flags &= ~R3964_ERROR;
 620                         pInfo->state = R3964_RECEIVING;
 621                         mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 622                         pInfo->nRetry = 0;
 623                         put_char(pInfo, DLE);
 624                         flush(pInfo);
 625                         pInfo->bcc = 0;
 626                 }
 627                 break;
 628         case R3964_RECEIVING:
 629                 if (pInfo->rx_position < RX_BUF_SIZE) {
 630                         pInfo->bcc ^= c;
 631
 632                         if (c == DLE) {
 633                                 if (pInfo->last_rx == DLE) {
 634                                         pInfo->last_rx = 0;
 635                                         goto char_to_buf;
 636                                 }
 637                                 pInfo->last_rx = DLE;
 638                                 break;
 639                         } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
 640                                 if (pInfo->flags & R3964_BCC) {
 641                                         pInfo->state = R3964_WAIT_FOR_BCC;
 642                                         mod_timer(&pInfo->tmr,
 643                                                   jiffies + R3964_TO_ZVZ);
 644                                 } else {
 645                                         on_receive_block(pInfo);
 646                                 }
 647                         } else {
 648                                 pInfo->last_rx = c;
 649 char_to_buf:
 650                                 pInfo->rx_buf[pInfo->rx_position++] = c;
 651                                 mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
 652                         }
 653                 }
 654                 /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
 655                 break;
 656         case R3964_WAIT_FOR_BCC:
 657                 pInfo->last_rx = c;
 658                 on_receive_block(pInfo);
 659                 break;
 660         }
 661 }
 662
 663 static void receive_error(struct r3964_info *pInfo, const char flag)
 664 {
 665         switch (flag) {
 666         case TTY_NORMAL:
 667                 break;
 668         case TTY_BREAK:
 669                 TRACE_PE("received break");
 670                 pInfo->flags |= R3964_BREAK;
 671                 break;
 672         case TTY_PARITY:
 673                 TRACE_PE("parity error");
 674                 pInfo->flags |= R3964_PARITY;
 675                 break;
 676         case TTY_FRAME:
 677                 TRACE_PE("frame error");
 678                 pInfo->flags |= R3964_FRAME;
 679                 break;
 680         case TTY_OVERRUN:
 681                 TRACE_PE("frame overrun");
 682                 pInfo->flags |= R3964_OVERRUN;
 683                 break;
 684         default:
 685                 TRACE_PE("receive_error - unknown flag %d", flag);
 686                 pInfo->flags |= R3964_UNKNOWN;
 687                 break;
 688         }
 689 }
 690
 691 static void on_timeout(struct timer_list *t)
 692 {
 693         struct r3964_info *pInfo = from_timer(pInfo, t, tmr);
 694
 695         switch (pInfo->state) {
 696         case R3964_TX_REQUEST:
 697                 TRACE_PE("TX_REQUEST - timeout");
 698                 retry_transmit(pInfo);
 699                 break;
 700         case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
 701                 put_char(pInfo, NAK);
 702                 flush(pInfo);
 703                 retry_transmit(pInfo);
 704                 break;
 705         case R3964_WAIT_FOR_TX_ACK:
 706                 TRACE_PE("WAIT_FOR_TX_ACK - timeout");
 707                 retry_transmit(pInfo);
 708                 break;
 709         case R3964_WAIT_FOR_RX_BUF:
 710                 TRACE_PE("WAIT_FOR_RX_BUF - timeout");
 711                 put_char(pInfo, NAK);
 712                 flush(pInfo);
 713                 pInfo->state = R3964_IDLE;
 714                 break;
 715         case R3964_RECEIVING:
 716                 TRACE_PE("RECEIVING - timeout after %d chars",
 717                          pInfo->rx_position);
 718                 put_char(pInfo, NAK);
 719                 flush(pInfo);
 720                 pInfo->state = R3964_IDLE;
 721                 break;
 722         case R3964_WAIT_FOR_RX_REPEAT:
 723                 TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
 724                 pInfo->state = R3964_IDLE;
 725                 break;
 726         case R3964_WAIT_FOR_BCC:
 727                 TRACE_PE("WAIT_FOR_BCC - timeout");
 728                 put_char(pInfo, NAK);
 729                 flush(pInfo);
 730                 pInfo->state = R3964_IDLE;
 731                 break;
 732         }
 733 }
 734
 735 static struct r3964_client_info *findClient(struct r3964_info *pInfo,
 736                 struct pid *pid)
 737 {
 738         struct r3964_client_info *pClient;
 739
 740         for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
 741                 if (pClient->pid == pid) {
 742                         return pClient;
 743                 }
 744         }
 745         return NULL;
 746 }
 747
 748 static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
 749 {
 750         struct r3964_client_info *pClient;
 751         struct r3964_client_info **ppClient;
 752         struct r3964_message *pMsg;
 753
 754         if ((arg & R3964_SIG_ALL) == 0) {
 755                 /* Remove client from client list */
 756                 for (ppClient = &pInfo->firstClient; *ppClient;
 757                      ppClient = &(*ppClient)->next) {
 758                         pClient = *ppClient;
 759
 760                         if (pClient->pid == pid) {
 761                                 TRACE_PS("removing client %d from client list",
 762                                          pid_nr(pid));
 763                                 *ppClient = pClient->next;
 764                                 while (pClient->msg_count) {
 765                                         pMsg = remove_msg(pInfo, pClient);
 766                                         if (pMsg) {
 767                                                 kfree(pMsg);
 768                                                 TRACE_M("enable_signals - msg "
 769                                                         "kfree %p", pMsg);
 770                                         }
 771                                 }
 772                                 put_pid(pClient->pid);
 773                                 kfree(pClient);
 774                                 TRACE_M("enable_signals - kfree %p", pClient);
 775                                 return 0;
 776                         }
 777                 }
 778                 return -EINVAL;
 779         } else {
 780                 pClient = findClient(pInfo, pid);
 781                 if (pClient) {
 782                         /* update signal options */
 783                         pClient->sig_flags = arg;
 784                 } else {
 785                         /* add client to client list */
 786                         pClient = kmalloc(sizeof(struct r3964_client_info),
 787                                         GFP_KERNEL);
 788                         TRACE_M("enable_signals - kmalloc %p", pClient);
 789                         if (pClient == NULL)
 790                                 return -ENOMEM;
 791
 792                         TRACE_PS("add client %d to client list", pid_nr(pid));
 793                         spin_lock_init(&pClient->lock);
 794                         pClient->sig_flags = arg;
 795                         pClient->pid = get_pid(pid);
 796                         pClient->next = pInfo->firstClient;
 797                         pClient->first_msg = NULL;
 798                         pClient->last_msg = NULL;
 799                         pClient->next_block_to_read = NULL;
 800                         pClient->msg_count = 0;
 801                         pInfo->firstClient = pClient;
 802                 }
 803         }
 804
 805         return 0;
 806 }
 807
 808 static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
 809                          unsigned char __user * buf)
 810 {
 811         struct r3964_client_info *pClient;
 812         struct r3964_block_header *block;
 813
 814         if (!buf) {
 815                 return -EINVAL;
 816         }
 817
 818         pClient = findClient(pInfo, pid);
 819         if (pClient == NULL) {
 820                 return -EINVAL;
 821         }
 822
 823         block = pClient->next_block_to_read;
 824         if (!block) {
 825                 return 0;
 826         } else {
 827                 if (copy_to_user(buf, block->data, block->length))
 828                         return -EFAULT;
 829
 830                 remove_client_block(pInfo, pClient);
 831                 return block->length;
 832         }
 833
 834         return -EINVAL;
 835 }
 836
 837 static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
 838                 int error_code, struct r3964_block_header *pBlock)
 839 {
 840         struct r3964_message *pMsg;
 841         unsigned long flags;
 842
 843         if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
 844 queue_the_message:
 845
 846                 pMsg = kmalloc(sizeof(struct r3964_message),
 847                                 error_code ? GFP_ATOMIC : GFP_KERNEL);
 848                 TRACE_M("add_msg - kmalloc %p", pMsg);
 849                 if (pMsg == NULL) {
 850                         return;
 851                 }
 852
 853                 spin_lock_irqsave(&pClient->lock, flags);
 854
 855                 pMsg->msg_id = msg_id;
 856                 pMsg->arg = arg;
 857                 pMsg->error_code = error_code;
 858                 pMsg->block = pBlock;
 859                 pMsg->next = NULL;
 860
 861                 if (pClient->last_msg == NULL) {
 862                         pClient->first_msg = pClient->last_msg = pMsg;
 863                 } else {
 864                         pClient->last_msg->next = pMsg;
 865                         pClient->last_msg = pMsg;
 866                 }
 867
 868                 pClient->msg_count++;
 869
 870                 if (pBlock != NULL) {
 871                         pBlock->locks++;
 872                 }
 873                 spin_unlock_irqrestore(&pClient->lock, flags);
 874         } else {
 875                 if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
 876                     && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
 877                         pClient->last_msg->arg++;
 878                         TRACE_PE("add_msg - inc prev OVERFLOW-msg");
 879                 } else {
 880                         msg_id = R3964_MSG_ACK;
 881                         arg = 0;
 882                         error_code = R3964_OVERFLOW;
 883                         pBlock = NULL;
 884                         TRACE_PE("add_msg - queue OVERFLOW-msg");
 885                         goto queue_the_message;
 886                 }
 887         }
 888         /* Send SIGIO signal to client process: */
 889         if (pClient->sig_flags & R3964_USE_SIGIO) {
 890                 kill_pid(pClient->pid, SIGIO, 1);
 891         }
 892 }
 893
 894 static struct r3964_message *remove_msg(struct r3964_info *pInfo,
 895                                         struct r3964_client_info *pClient)
 896 {
 897         struct r3964_message *pMsg = NULL;
 898         unsigned long flags;
 899
 900         if (pClient->first_msg) {
 901                 spin_lock_irqsave(&pClient->lock, flags);
 902
 903                 pMsg = pClient->first_msg;
 904                 pClient->first_msg = pMsg->next;
 905                 if (pClient->first_msg == NULL) {
 906                         pClient->last_msg = NULL;
 907                 }
 908
 909                 pClient->msg_count--;
 910                 if (pMsg->block) {
 911                         remove_client_block(pInfo, pClient);
 912                         pClient->next_block_to_read = pMsg->block;
 913                 }
 914                 spin_unlock_irqrestore(&pClient->lock, flags);
 915         }
 916         return pMsg;
 917 }
 918
 919 static void remove_client_block(struct r3964_info *pInfo,
 920                                 struct r3964_client_info *pClient)
 921 {
 922         struct r3964_block_header *block;
 923
 924         TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
 925
 926         block = pClient->next_block_to_read;
 927         if (block) {
 928                 block->locks--;
 929                 if (block->locks == 0) {
 930                         remove_from_rx_queue(pInfo, block);
 931                 }
 932         }
 933         pClient->next_block_to_read = NULL;
 934 }
 935
 936 /*************************************************************
 937  * Line discipline routines
 938  *************************************************************/
 939
 940 static int r3964_open(struct tty_struct *tty)
 941 {
 942         struct r3964_info *pInfo;
 943
 944         TRACE_L("open");
 945         TRACE_L("tty=%p, PID=%d, disc_data=%p",
 946                 tty, current->pid, tty->disc_data);
 947
 948         pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
 949         TRACE_M("r3964_open - info kmalloc %p", pInfo);
 950
 951         if (!pInfo) {
 952                 printk(KERN_ERR "r3964: failed to alloc info structure\n");
 953                 return -ENOMEM;
 954         }
 955
 956         pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
 957         TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
 958
 959         if (!pInfo->rx_buf) {
 960                 printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
 961                 kfree(pInfo);
 962                 TRACE_M("r3964_open - info kfree %p", pInfo);
 963                 return -ENOMEM;
 964         }
 965
 966         pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
 967         TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
 968
 969         if (!pInfo->tx_buf) {
 970                 printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
 971                 kfree(pInfo->rx_buf);
 972                 TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
 973                 kfree(pInfo);
 974                 TRACE_M("r3964_open - info kfree %p", pInfo);
 975                 return -ENOMEM;
 976         }
 977
 978         spin_lock_init(&pInfo->lock);
 979         mutex_init(&pInfo->read_lock);
 980         pInfo->tty = tty;
 981         pInfo->priority = R3964_MASTER;
 982         pInfo->rx_first = pInfo->rx_last = NULL;
 983         pInfo->tx_first = pInfo->tx_last = NULL;
 984         pInfo->rx_position = 0;
 985         pInfo->tx_position = 0;
 986         pInfo->last_rx = 0;
 987         pInfo->blocks_in_rx_queue = 0;
 988         pInfo->firstClient = NULL;
 989         pInfo->state = R3964_IDLE;
 990         pInfo->flags = R3964_DEBUG;
 991         pInfo->nRetry = 0;
 992
 993         tty->disc_data = pInfo;
 994         tty->receive_room = 65536;
 995
 996         timer_setup(&pInfo->tmr, on_timeout, 0);
 997
 998         return 0;
 999 }
1000
1001 static void r3964_close(struct tty_struct *tty)
1002 {
1003         struct r3964_info *pInfo = tty->disc_data;
1004         struct r3964_client_info *pClient, *pNext;
1005         struct r3964_message *pMsg;
1006         struct r3964_block_header *pHeader, *pNextHeader;
1007         unsigned long flags;
1008
1009         TRACE_L("close");
1010
1011         /*
1012          * Make sure that our task queue isn't activated.  If it
1013          * is, take it out of the linked list.
1014          */
1015         del_timer_sync(&pInfo->tmr);
1016
1017         /* Remove client-structs and message queues: */
1018         pClient = pInfo->firstClient;
1019         while (pClient) {
1020                 pNext = pClient->next;
1021                 while (pClient->msg_count) {
1022                         pMsg = remove_msg(pInfo, pClient);
1023                         if (pMsg) {
1024                                 kfree(pMsg);
1025                                 TRACE_M("r3964_close - msg kfree %p", pMsg);
1026                         }
1027                 }
1028                 put_pid(pClient->pid);
1029                 kfree(pClient);
1030                 TRACE_M("r3964_close - client kfree %p", pClient);
1031                 pClient = pNext;
1032         }
1033         /* Remove jobs from tx_queue: */
1034         spin_lock_irqsave(&pInfo->lock, flags);
1035         pHeader = pInfo->tx_first;
1036         pInfo->tx_first = pInfo->tx_last = NULL;
1037         spin_unlock_irqrestore(&pInfo->lock, flags);
1038
1039         while (pHeader) {
1040                 pNextHeader = pHeader->next;
1041                 kfree(pHeader);
1042                 pHeader = pNextHeader;
1043         }
1044
1045         /* Free buffers: */
1046         kfree(pInfo->rx_buf);
1047         TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1048         kfree(pInfo->tx_buf);
1049         TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1050         kfree(pInfo);
1051         TRACE_M("r3964_close - info kfree %p", pInfo);
1052 }
1053
1054 static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1055                           unsigned char __user * buf, size_t nr)
1056 {
1057         struct r3964_info *pInfo = tty->disc_data;
1058         struct r3964_client_info *pClient;
1059         struct r3964_message *pMsg;
1060         struct r3964_client_message theMsg;
1061         int ret;
1062
1063         TRACE_L("read()");
1064
1065         /*
1066          *      Internal serialization of reads.
1067          */
1068         if (file->f_flags & O_NONBLOCK) {
1069                 if (!mutex_trylock(&pInfo->read_lock))
1070                         return -EAGAIN;
1071         } else {
1072                 if (mutex_lock_interruptible(&pInfo->read_lock))
1073                         return -ERESTARTSYS;
1074         }
1075
1076         pClient = findClient(pInfo, task_pid(current));
1077         if (pClient) {
1078                 pMsg = remove_msg(pInfo, pClient);
1079                 if (pMsg == NULL) {
1080                         /* no messages available. */
1081                         if (file->f_flags & O_NONBLOCK) {
1082                                 ret = -EAGAIN;
1083                                 goto unlock;
1084                         }
1085                         /* block until there is a message: */
1086                         wait_event_interruptible(tty->read_wait,
1087                                         (pMsg = remove_msg(pInfo, pClient)));
1088                 }
1089
1090                 /* If we still haven't got a message, we must have been signalled */
1091
1092                 if (!pMsg) {
1093                         ret = -EINTR;
1094                         goto unlock;
1095                 }
1096
1097                 /* deliver msg to client process: */
1098                 theMsg.msg_id = pMsg->msg_id;
1099                 theMsg.arg = pMsg->arg;
1100                 theMsg.error_code = pMsg->error_code;
1101                 ret = sizeof(struct r3964_client_message);
1102
1103                 kfree(pMsg);
1104                 TRACE_M("r3964_read - msg kfree %p", pMsg);
1105
1106                 if (copy_to_user(buf, &theMsg, ret)) {
1107                         ret = -EFAULT;
1108                         goto unlock;
1109                 }
1110
1111                 TRACE_PS("read - return %d", ret);
1112                 goto unlock;
1113         }
1114         ret = -EPERM;
1115 unlock:
1116         mutex_unlock(&pInfo->read_lock);
1117         return ret;
1118 }
1119
1120 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1121                            const unsigned char *data, size_t count)
1122 {
1123         struct r3964_info *pInfo = tty->disc_data;
1124         struct r3964_block_header *pHeader;
1125         struct r3964_client_info *pClient;
1126         unsigned char *new_data;
1127
1128         TRACE_L("write request, %d characters", count);
1129 /*
1130  * Verify the pointers
1131  */
1132
1133         if (!pInfo)
1134                 return -EIO;
1135
1136 /*
1137  * Ensure that the caller does not wish to send too much.
1138  */
1139         if (count > R3964_MTU) {
1140                 if (pInfo->flags & R3964_DEBUG) {
1141                         TRACE_L(KERN_WARNING "r3964_write: truncating user "
1142                                 "packet from %u to mtu %d", count, R3964_MTU);
1143                 }
1144                 count = R3964_MTU;
1145         }
1146 /*
1147  * Allocate a buffer for the data and copy it from the buffer with header prepended
1148  */
1149         new_data = kmalloc(count + sizeof(struct r3964_block_header),
1150                         GFP_KERNEL);
1151         TRACE_M("r3964_write - kmalloc %p", new_data);
1152         if (new_data == NULL) {
1153                 if (pInfo->flags & R3964_DEBUG) {
1154                         printk(KERN_ERR "r3964_write: no memory\n");
1155                 }
1156                 return -ENOSPC;
1157         }
1158
1159         pHeader = (struct r3964_block_header *)new_data;
1160         pHeader->data = new_data + sizeof(struct r3964_block_header);
1161         pHeader->length = count;
1162         pHeader->locks = 0;
1163         pHeader->owner = NULL;
1164
1165         pClient = findClient(pInfo, task_pid(current));
1166         if (pClient) {
1167                 pHeader->owner = pClient;
1168         }
1169
1170         memcpy(pHeader->data, data, count);     /* We already verified this */
1171
1172         if (pInfo->flags & R3964_DEBUG) {
1173                 dump_block(pHeader->data, count);
1174         }
1175
1176 /*
1177  * Add buffer to transmit-queue:
1178  */
1179         add_tx_queue(pInfo, pHeader);
1180         trigger_transmit(pInfo);
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 __poll_t 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         __poll_t result = POLLOUT;
1227
1228         TRACE_L("POLL");
1229
1230         pClient = findClient(pInfo, task_pid(current));
1231         if (pClient) {
1232                 poll_wait(file, &tty->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 = TTY_NORMAL;
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);