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