drivers/s390/net/ctctty.c

   1 /*
   2  * $Id: ctctty.c,v 1.29 2005/04/05 08:50:44 mschwide Exp $
   3  *
   4  * CTC / ESCON network driver, tty interface.
   5  *
   6  * Copyright (C) 2001 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  * Author(s): Fritz Elfert (elfert@de.ibm.com, felfert@millenux.com)
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2, or (at your option)
  12  * any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  */
  24
  25 #include <linux/config.h>
  26 #include <linux/module.h>
  27 #include <linux/tty.h>
  28 #include <linux/serial_reg.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/delay.h>
  31 #include <asm/uaccess.h>
  32 #include <linux/devfs_fs_kernel.h>
  33 #include "ctctty.h"
  34 #include "ctcdbug.h"
  35
  36 #define CTC_TTY_MAJOR       43
  37 #define CTC_TTY_MAX_DEVICES 64
  38
  39 #define CTC_ASYNC_MAGIC          0x49344C01 /* for paranoia-checking        */
  40 #define CTC_ASYNC_INITIALIZED    0x80000000 /* port was initialized         */
  41 #define CTC_ASYNC_NORMAL_ACTIVE  0x20000000 /* Normal device active         */
  42 #define CTC_ASYNC_CLOSING        0x08000000 /* Serial port is closing       */
  43 #define CTC_ASYNC_CTS_FLOW       0x04000000 /* Do CTS flow control          */
  44 #define CTC_ASYNC_CHECK_CD       0x02000000 /* i.e., CLOCAL                 */
  45 #define CTC_ASYNC_HUP_NOTIFY         0x0001 /* Notify tty on hangups/closes */
  46 #define CTC_ASYNC_NETDEV_OPEN        0x0002 /* Underlying netdev is open    */
  47 #define CTC_ASYNC_TX_LINESTAT        0x0004 /* Must send line status        */
  48 #define CTC_ASYNC_SPLIT_TERMIOS      0x0008 /* Sep. termios for dialin/out  */
  49 #define CTC_TTY_XMIT_SIZE              1024 /* Default bufsize for write    */
  50 #define CTC_SERIAL_XMIT_MAX            4000 /* Maximum bufsize for write    */
  51
  52 /* Private data (similar to async_struct in <linux/serial.h>) */
  53 typedef struct {
  54   int                   magic;
  55   int                   flags;           /* defined in tty.h               */
  56   int                   mcr;             /* Modem control register         */
  57   int                   msr;             /* Modem status register          */
  58   int                   lsr;             /* Line status register           */
  59   int                   line;
  60   int                   count;           /* # of fd on device              */
  61   int                   blocked_open;    /* # of blocked opens             */
  62   struct net_device     *netdev;
  63   struct sk_buff_head   tx_queue;        /* transmit queue                 */
  64   struct sk_buff_head   rx_queue;        /* receive queue                  */
  65   struct tty_struct     *tty;            /* Pointer to corresponding tty   */
  66   wait_queue_head_t     open_wait;
  67   wait_queue_head_t     close_wait;
  68   struct semaphore      write_sem;
  69   struct tasklet_struct tasklet;
  70   struct timer_list     stoptimer;
  71 } ctc_tty_info;
  72
  73 /* Description of one CTC-tty */
  74 typedef struct {
  75   struct tty_driver  *ctc_tty_device;              /* tty-device             */
  76   ctc_tty_info       info[CTC_TTY_MAX_DEVICES];    /* Private data           */
  77 } ctc_tty_driver;
  78
  79 static ctc_tty_driver *driver;
  80
  81 /* Leave this unchanged unless you know what you do! */
  82 #define MODEM_PARANOIA_CHECK
  83 #define MODEM_DO_RESTART
  84
  85 #define CTC_TTY_NAME "ctctty"
  86
  87 static __u32 ctc_tty_magic = CTC_ASYNC_MAGIC;
  88 static int ctc_tty_shuttingdown = 0;
  89
  90 static spinlock_t ctc_tty_lock;
  91
  92 /* ctc_tty_try_read() is called from within ctc_tty_rcv_skb()
  93  * to stuff incoming data directly into a tty's flip-buffer. If the
  94  * flip buffer is full, the packet gets queued up.
  95  *
  96  * Return:
  97  *  1 = Success
  98  *  0 = Failure, data has to be buffered and later processed by
  99  *      ctc_tty_readmodem().
 100  */
 101 static int
 102 ctc_tty_try_read(ctc_tty_info * info, struct sk_buff *skb)
 103 {
 104         int c;
 105         int len;
 106         struct tty_struct *tty;
 107
 108         DBF_TEXT(trace, 5, __FUNCTION__);
 109         if ((tty = info->tty)) {
 110                 if (info->mcr & UART_MCR_RTS) {
 111                         c = TTY_FLIPBUF_SIZE - tty->flip.count;
 112                         len = skb->len;
 113                         if (c >= len) {
 114                                 memcpy(tty->flip.char_buf_ptr, skb->data, len);
 115                                 memset(tty->flip.flag_buf_ptr, 0, len);
 116                                 tty->flip.count += len;
 117                                 tty->flip.char_buf_ptr += len;
 118                                 tty->flip.flag_buf_ptr += len;
 119                                 tty_flip_buffer_push(tty);
 120                                 kfree_skb(skb);
 121                                 return 1;
 122                         }
 123                 }
 124         }
 125         return 0;
 126 }
 127
 128 /* ctc_tty_readmodem() is called periodically from within timer-interrupt.
 129  * It tries getting received data from the receive queue an stuff it into
 130  * the tty's flip-buffer.
 131  */
 132 static int
 133 ctc_tty_readmodem(ctc_tty_info *info)
 134 {
 135         int ret = 1;
 136         struct tty_struct *tty;
 137
 138         DBF_TEXT(trace, 5, __FUNCTION__);
 139         if ((tty = info->tty)) {
 140                 if (info->mcr & UART_MCR_RTS) {
 141                         int c = TTY_FLIPBUF_SIZE - tty->flip.count;
 142                         struct sk_buff *skb;
 143
 144                         if ((c > 0) && (skb = skb_dequeue(&info->rx_queue))) {
 145                                 int len = skb->len;
 146                                 if (len > c)
 147                                         len = c;
 148                                 memcpy(tty->flip.char_buf_ptr, skb->data, len);
 149                                 skb_pull(skb, len);
 150                                 memset(tty->flip.flag_buf_ptr, 0, len);
 151                                 tty->flip.count += len;
 152                                 tty->flip.char_buf_ptr += len;
 153                                 tty->flip.flag_buf_ptr += len;
 154                                 tty_flip_buffer_push(tty);
 155                                 if (skb->len > 0)
 156                                         skb_queue_head(&info->rx_queue, skb);
 157                                 else {
 158                                         kfree_skb(skb);
 159                                         ret = skb_queue_len(&info->rx_queue);
 160                                 }
 161                         }
 162                 }
 163         }
 164         return ret;
 165 }
 166
 167 void
 168 ctc_tty_setcarrier(struct net_device *netdev, int on)
 169 {
 170         int i;
 171
 172         DBF_TEXT(trace, 4, __FUNCTION__);
 173         if ((!driver) || ctc_tty_shuttingdown)
 174                 return;
 175         for (i = 0; i < CTC_TTY_MAX_DEVICES; i++)
 176                 if (driver->info[i].netdev == netdev) {
 177                         ctc_tty_info *info = &driver->info[i];
 178                         if (on)
 179                                 info->msr |= UART_MSR_DCD;
 180                         else
 181                                 info->msr &= ~UART_MSR_DCD;
 182                         if ((info->flags & CTC_ASYNC_CHECK_CD) && (!on))
 183                                 tty_hangup(info->tty);
 184                 }
 185 }
 186
 187 void
 188 ctc_tty_netif_rx(struct sk_buff *skb)
 189 {
 190         int i;
 191         ctc_tty_info *info = NULL;
 192
 193         DBF_TEXT(trace, 5, __FUNCTION__);
 194         if (!skb)
 195                 return;
 196         if ((!skb->dev) || (!driver) || ctc_tty_shuttingdown) {
 197                 dev_kfree_skb(skb);
 198                 return;
 199         }
 200         for (i = 0; i < CTC_TTY_MAX_DEVICES; i++)
 201                 if (driver->info[i].netdev == skb->dev) {
 202                         info = &driver->info[i];
 203                         break;
 204                 }
 205         if (!info) {
 206                 dev_kfree_skb(skb);
 207                 return;
 208         }
 209         if (skb->len < 6) {
 210                 dev_kfree_skb(skb);
 211                 return;
 212         }
 213         if (memcmp(skb->data, &ctc_tty_magic, sizeof(__u32))) {
 214                 dev_kfree_skb(skb);
 215                 return;
 216         }
 217         skb_pull(skb, sizeof(__u32));
 218
 219         i = *((int *)skb->data);
 220         skb_pull(skb, sizeof(info->mcr));
 221         if (i & UART_MCR_RTS) {
 222                 info->msr |= UART_MSR_CTS;
 223                 if (info->flags & CTC_ASYNC_CTS_FLOW)
 224                         info->tty->hw_stopped = 0;
 225         } else {
 226                 info->msr &= ~UART_MSR_CTS;
 227                 if (info->flags & CTC_ASYNC_CTS_FLOW)
 228                         info->tty->hw_stopped = 1;
 229         }
 230         if (i & UART_MCR_DTR)
 231                 info->msr |= UART_MSR_DSR;
 232         else
 233                 info->msr &= ~UART_MSR_DSR;
 234         if (skb->len <= 0) {
 235                 kfree_skb(skb);
 236                 return;
 237         }
 238         /* Try to deliver directly via tty-flip-buf if queue is empty */
 239         if (skb_queue_empty(&info->rx_queue))
 240                 if (ctc_tty_try_read(info, skb))
 241                         return;
 242         /* Direct deliver failed or queue wasn't empty.
 243          * Queue up for later dequeueing via timer-irq.
 244          */
 245         skb_queue_tail(&info->rx_queue, skb);
 246         /* Schedule dequeuing */
 247         tasklet_schedule(&info->tasklet);
 248 }
 249
 250 static int
 251 ctc_tty_tint(ctc_tty_info * info)
 252 {
 253         struct sk_buff *skb = skb_dequeue(&info->tx_queue);
 254         int stopped = (info->tty->hw_stopped || info->tty->stopped);
 255         int wake = 1;
 256         int rc;
 257
 258         DBF_TEXT(trace, 4, __FUNCTION__);
 259         if (!info->netdev) {
 260                 if (skb)
 261                         kfree_skb(skb);
 262                 return 0;
 263         }
 264         if (info->flags & CTC_ASYNC_TX_LINESTAT) {
 265                 int skb_res = info->netdev->hard_header_len +
 266                         sizeof(info->mcr) + sizeof(__u32);
 267                 /* If we must update line status,
 268                  * create an empty dummy skb and insert it.
 269                  */
 270                 if (skb)
 271                         skb_queue_head(&info->tx_queue, skb);
 272
 273                 skb = dev_alloc_skb(skb_res);
 274                 if (!skb) {
 275                         printk(KERN_WARNING
 276                                "ctc_tty: Out of memory in %s%d tint\n",
 277                                CTC_TTY_NAME, info->line);
 278                         return 1;
 279                 }
 280                 skb_reserve(skb, skb_res);
 281                 stopped = 0;
 282                 wake = 0;
 283         }
 284         if (!skb)
 285                 return 0;
 286         if (stopped) {
 287                 skb_queue_head(&info->tx_queue, skb);
 288                 return 1;
 289         }
 290 #if 0
 291         if (skb->len > 0)
 292                 printk(KERN_DEBUG "tint: %d %02x\n", skb->len, *(skb->data));
 293         else
 294                 printk(KERN_DEBUG "tint: %d STAT\n", skb->len);
 295 #endif
 296         memcpy(skb_push(skb, sizeof(info->mcr)), &info->mcr, sizeof(info->mcr));
 297         memcpy(skb_push(skb, sizeof(__u32)), &ctc_tty_magic, sizeof(__u32));
 298         rc = info->netdev->hard_start_xmit(skb, info->netdev);
 299         if (rc) {
 300                 skb_pull(skb, sizeof(info->mcr) + sizeof(__u32));
 301                 if (skb->len > 0)
 302                         skb_queue_head(&info->tx_queue, skb);
 303                 else
 304                         kfree_skb(skb);
 305         } else {
 306                 struct tty_struct *tty = info->tty;
 307
 308                 info->flags &= ~CTC_ASYNC_TX_LINESTAT;
 309                 if (tty) {
 310                         tty_wakeup(tty);
 311                 }
 312         }
 313         return (skb_queue_empty(&info->tx_queue) ? 0 : 1);
 314 }
 315
 316 /************************************************************
 317  *
 318  * Modem-functions
 319  *
 320  * mostly "stolen" from original Linux-serial.c and friends.
 321  *
 322  ************************************************************/
 323
 324 static inline int
 325 ctc_tty_paranoia_check(ctc_tty_info * info, char *name, const char *routine)
 326 {
 327 #ifdef MODEM_PARANOIA_CHECK
 328         if (!info) {
 329                 printk(KERN_WARNING "ctc_tty: null info_struct for %s in %s\n",
 330                        name, routine);
 331                 return 1;
 332         }
 333         if (info->magic != CTC_ASYNC_MAGIC) {
 334                 printk(KERN_WARNING "ctc_tty: bad magic for info struct %s in %s\n",
 335                        name, routine);
 336                 return 1;
 337         }
 338 #endif
 339         return 0;
 340 }
 341
 342 static void
 343 ctc_tty_inject(ctc_tty_info *info, char c)
 344 {
 345         int skb_res;
 346         struct sk_buff *skb;
 347
 348         DBF_TEXT(trace, 4, __FUNCTION__);
 349         if (ctc_tty_shuttingdown)
 350                 return;
 351         skb_res = info->netdev->hard_header_len + sizeof(info->mcr) +
 352                 sizeof(__u32) + 1;
 353         skb = dev_alloc_skb(skb_res);
 354         if (!skb) {
 355                 printk(KERN_WARNING
 356                        "ctc_tty: Out of memory in %s%d tx_inject\n",
 357                        CTC_TTY_NAME, info->line);
 358                 return;
 359         }
 360         skb_reserve(skb, skb_res);
 361         *(skb_put(skb, 1)) = c;
 362         skb_queue_head(&info->tx_queue, skb);
 363         tasklet_schedule(&info->tasklet);
 364 }
 365
 366 static void
 367 ctc_tty_transmit_status(ctc_tty_info *info)
 368 {
 369         DBF_TEXT(trace, 5, __FUNCTION__);
 370         if (ctc_tty_shuttingdown)
 371                 return;
 372         info->flags |= CTC_ASYNC_TX_LINESTAT;
 373         tasklet_schedule(&info->tasklet);
 374 }
 375
 376 static void
 377 ctc_tty_change_speed(ctc_tty_info * info)
 378 {
 379         unsigned int cflag;
 380         unsigned int quot;
 381         int i;
 382
 383         DBF_TEXT(trace, 3, __FUNCTION__);
 384         if (!info->tty || !info->tty->termios)
 385                 return;
 386         cflag = info->tty->termios->c_cflag;
 387
 388         quot = i = cflag & CBAUD;
 389         if (i & CBAUDEX) {
 390                 i &= ~CBAUDEX;
 391                 if (i < 1 || i > 2)
 392                         info->tty->termios->c_cflag &= ~CBAUDEX;
 393                 else
 394                         i += 15;
 395         }
 396         if (quot) {
 397                 info->mcr |= UART_MCR_DTR;
 398                 info->mcr |= UART_MCR_RTS;
 399                 ctc_tty_transmit_status(info);
 400         } else {
 401                 info->mcr &= ~UART_MCR_DTR;
 402                 info->mcr &= ~UART_MCR_RTS;
 403                 ctc_tty_transmit_status(info);
 404                 return;
 405         }
 406
 407         /* CTS flow control flag and modem status interrupts */
 408         if (cflag & CRTSCTS) {
 409                 info->flags |= CTC_ASYNC_CTS_FLOW;
 410         } else
 411                 info->flags &= ~CTC_ASYNC_CTS_FLOW;
 412         if (cflag & CLOCAL)
 413                 info->flags &= ~CTC_ASYNC_CHECK_CD;
 414         else {
 415                 info->flags |= CTC_ASYNC_CHECK_CD;
 416         }
 417 }
 418
 419 static int
 420 ctc_tty_startup(ctc_tty_info * info)
 421 {
 422         DBF_TEXT(trace, 3, __FUNCTION__);
 423         if (info->flags & CTC_ASYNC_INITIALIZED)
 424                 return 0;
 425 #ifdef CTC_DEBUG_MODEM_OPEN
 426         printk(KERN_DEBUG "starting up %s%d ...\n", CTC_TTY_NAME, info->line);
 427 #endif
 428         /*
 429          * Now, initialize the UART
 430          */
 431         info->mcr = UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2;
 432         if (info->tty)
 433                 clear_bit(TTY_IO_ERROR, &info->tty->flags);
 434         /*
 435          * and set the speed of the serial port
 436          */
 437         ctc_tty_change_speed(info);
 438
 439         info->flags |= CTC_ASYNC_INITIALIZED;
 440         if (!(info->flags & CTC_ASYNC_NETDEV_OPEN))
 441                 info->netdev->open(info->netdev);
 442         info->flags |= CTC_ASYNC_NETDEV_OPEN;
 443         return 0;
 444 }
 445
 446 static void
 447 ctc_tty_stopdev(unsigned long data)
 448 {
 449         ctc_tty_info *info = (ctc_tty_info *)data;
 450
 451         if ((!info) || (!info->netdev) ||
 452             (info->flags & CTC_ASYNC_INITIALIZED))
 453                 return;
 454         info->netdev->stop(info->netdev);
 455         info->flags &= ~CTC_ASYNC_NETDEV_OPEN;
 456 }
 457
 458 /*
 459  * This routine will shutdown a serial port; interrupts are disabled, and
 460  * DTR is dropped if the hangup on close termio flag is on.
 461  */
 462 static void
 463 ctc_tty_shutdown(ctc_tty_info * info)
 464 {
 465         DBF_TEXT(trace, 3, __FUNCTION__);
 466         if (!(info->flags & CTC_ASYNC_INITIALIZED))
 467                 return;
 468 #ifdef CTC_DEBUG_MODEM_OPEN
 469         printk(KERN_DEBUG "Shutting down %s%d ....\n", CTC_TTY_NAME, info->line);
 470 #endif
 471         info->msr &= ~UART_MSR_RI;
 472         if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
 473                 info->mcr &= ~(UART_MCR_DTR | UART_MCR_RTS);
 474         if (info->tty)
 475                 set_bit(TTY_IO_ERROR, &info->tty->flags);
 476         mod_timer(&info->stoptimer, jiffies + (10 * HZ));
 477         skb_queue_purge(&info->tx_queue);
 478         skb_queue_purge(&info->rx_queue);
 479         info->flags &= ~CTC_ASYNC_INITIALIZED;
 480 }
 481
 482 /* ctc_tty_write() is the main send-routine. It is called from the upper
 483  * levels within the kernel to perform sending data. Depending on the
 484  * online-flag it either directs output to the at-command-interpreter or
 485  * to the lower level. Additional tasks done here:
 486  *  - If online, check for escape-sequence (+++)
 487  *  - If sending audio-data, call ctc_tty_DLEdown() to parse DLE-codes.
 488  *  - If receiving audio-data, call ctc_tty_end_vrx() to abort if needed.
 489  *  - If dialing, abort dial.
 490  */
 491 static int
 492 ctc_tty_write(struct tty_struct *tty, const u_char * buf, int count)
 493 {
 494         int c;
 495         int total = 0;
 496         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 497
 498         DBF_TEXT(trace, 5, __FUNCTION__);
 499         if (ctc_tty_shuttingdown)
 500                 goto ex;
 501         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_write"))
 502                 goto ex;
 503         if (!tty)
 504                 goto ex;
 505         if (!info->netdev) {
 506                 total = -ENODEV;
 507                 goto ex;
 508         }
 509         while (1) {
 510                 struct sk_buff *skb;
 511                 int skb_res;
 512
 513                 c = (count < CTC_TTY_XMIT_SIZE) ? count : CTC_TTY_XMIT_SIZE;
 514                 if (c <= 0)
 515                         break;
 516
 517                 skb_res = info->netdev->hard_header_len + sizeof(info->mcr) +
 518                         + sizeof(__u32);
 519                 skb = dev_alloc_skb(skb_res + c);
 520                 if (!skb) {
 521                         printk(KERN_WARNING
 522                                "ctc_tty: Out of memory in %s%d write\n",
 523                                CTC_TTY_NAME, info->line);
 524                         break;
 525                 }
 526                 skb_reserve(skb, skb_res);
 527                 memcpy(skb_put(skb, c), buf, c);
 528                 skb_queue_tail(&info->tx_queue, skb);
 529                 buf += c;
 530                 total += c;
 531                 count -= c;
 532         }
 533         if (skb_queue_len(&info->tx_queue)) {
 534                 info->lsr &= ~UART_LSR_TEMT;
 535                 tasklet_schedule(&info->tasklet);
 536         }
 537 ex:
 538         DBF_TEXT(trace, 6, __FUNCTION__);
 539         return total;
 540 }
 541
 542 static int
 543 ctc_tty_write_room(struct tty_struct *tty)
 544 {
 545         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 546
 547         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_write_room"))
 548                 return 0;
 549         return CTC_TTY_XMIT_SIZE;
 550 }
 551
 552 static int
 553 ctc_tty_chars_in_buffer(struct tty_struct *tty)
 554 {
 555         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 556
 557         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_chars_in_buffer"))
 558                 return 0;
 559         return 0;
 560 }
 561
 562 static void
 563 ctc_tty_flush_buffer(struct tty_struct *tty)
 564 {
 565         ctc_tty_info *info;
 566         unsigned long flags;
 567
 568         DBF_TEXT(trace, 4, __FUNCTION__);
 569         if (!tty)
 570                 goto ex;
 571         spin_lock_irqsave(&ctc_tty_lock, flags);
 572         info = (ctc_tty_info *) tty->driver_data;
 573         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_flush_buffer")) {
 574                 spin_unlock_irqrestore(&ctc_tty_lock, flags);
 575                 goto ex;
 576         }
 577         skb_queue_purge(&info->tx_queue);
 578         info->lsr |= UART_LSR_TEMT;
 579         spin_unlock_irqrestore(&ctc_tty_lock, flags);
 580         wake_up_interruptible(&tty->write_wait);
 581         tty_wakeup(tty);
 582 ex:
 583         DBF_TEXT_(trace, 2, "ex: %s ", __FUNCTION__);
 584         return;
 585 }
 586
 587 static void
 588 ctc_tty_flush_chars(struct tty_struct *tty)
 589 {
 590         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 591
 592         DBF_TEXT(trace, 4, __FUNCTION__);
 593         if (ctc_tty_shuttingdown)
 594                 return;
 595         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_flush_chars"))
 596                 return;
 597         if (tty->stopped || tty->hw_stopped || (!skb_queue_len(&info->tx_queue)))
 598                 return;
 599         tasklet_schedule(&info->tasklet);
 600 }
 601
 602 /*
 603  * ------------------------------------------------------------
 604  * ctc_tty_throttle()
 605  *
 606  * This routine is called by the upper-layer tty layer to signal that
 607  * incoming characters should be throttled.
 608  * ------------------------------------------------------------
 609  */
 610 static void
 611 ctc_tty_throttle(struct tty_struct *tty)
 612 {
 613         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 614
 615         DBF_TEXT(trace, 4, __FUNCTION__);
 616         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_throttle"))
 617                 return;
 618         info->mcr &= ~UART_MCR_RTS;
 619         if (I_IXOFF(tty))
 620                 ctc_tty_inject(info, STOP_CHAR(tty));
 621         ctc_tty_transmit_status(info);
 622 }
 623
 624 static void
 625 ctc_tty_unthrottle(struct tty_struct *tty)
 626 {
 627         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 628
 629         DBF_TEXT(trace, 4, __FUNCTION__);
 630         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_unthrottle"))
 631                 return;
 632         info->mcr |= UART_MCR_RTS;
 633         if (I_IXOFF(tty))
 634                 ctc_tty_inject(info, START_CHAR(tty));
 635         ctc_tty_transmit_status(info);
 636 }
 637
 638 /*
 639  * ------------------------------------------------------------
 640  * ctc_tty_ioctl() and friends
 641  * ------------------------------------------------------------
 642  */
 643
 644 /*
 645  * ctc_tty_get_lsr_info - get line status register info
 646  *
 647  * Purpose: Let user call ioctl() to get info when the UART physically
 648  *          is emptied.  On bus types like RS485, the transmitter must
 649  *          release the bus after transmitting. This must be done when
 650  *          the transmit shift register is empty, not be done when the
 651  *          transmit holding register is empty.  This functionality
 652  *          allows RS485 driver to be written in user space.
 653  */
 654 static int
 655 ctc_tty_get_lsr_info(ctc_tty_info * info, uint __user *value)
 656 {
 657         u_char status;
 658         uint result;
 659         ulong flags;
 660
 661         DBF_TEXT(trace, 4, __FUNCTION__);
 662         spin_lock_irqsave(&ctc_tty_lock, flags);
 663         status = info->lsr;
 664         spin_unlock_irqrestore(&ctc_tty_lock, flags);
 665         result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
 666         put_user(result, value);
 667         return 0;
 668 }
 669
 670
 671 static int ctc_tty_tiocmget(struct tty_struct *tty, struct file *file)
 672 {
 673         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 674         u_char control,
 675          status;
 676         uint result;
 677         ulong flags;
 678
 679         DBF_TEXT(trace, 4, __FUNCTION__);
 680         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_ioctl"))
 681                 return -ENODEV;
 682         if (tty->flags & (1 << TTY_IO_ERROR))
 683                 return -EIO;
 684
 685         control = info->mcr;
 686         spin_lock_irqsave(&ctc_tty_lock, flags);
 687         status = info->msr;
 688         spin_unlock_irqrestore(&ctc_tty_lock, flags);
 689         result = ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
 690             | ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
 691             | ((status & UART_MSR_DCD) ? TIOCM_CAR : 0)
 692             | ((status & UART_MSR_RI) ? TIOCM_RNG : 0)
 693             | ((status & UART_MSR_DSR) ? TIOCM_DSR : 0)
 694             | ((status & UART_MSR_CTS) ? TIOCM_CTS : 0);
 695         return result;
 696 }
 697
 698 static int
 699 ctc_tty_tiocmset(struct tty_struct *tty, struct file *file,
 700                  unsigned int set, unsigned int clear)
 701 {
 702         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 703
 704         DBF_TEXT(trace, 4, __FUNCTION__);
 705         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_ioctl"))
 706                 return -ENODEV;
 707         if (tty->flags & (1 << TTY_IO_ERROR))
 708                 return -EIO;
 709
 710         if (set & TIOCM_RTS)
 711                 info->mcr |= UART_MCR_RTS;
 712         if (set & TIOCM_DTR)
 713                 info->mcr |= UART_MCR_DTR;
 714
 715         if (clear & TIOCM_RTS)
 716                 info->mcr &= ~UART_MCR_RTS;
 717         if (clear & TIOCM_DTR)
 718                 info->mcr &= ~UART_MCR_DTR;
 719
 720         if ((set | clear) & (TIOCM_RTS|TIOCM_DTR))
 721                 ctc_tty_transmit_status(info);
 722         return 0;
 723 }
 724
 725 static int
 726 ctc_tty_ioctl(struct tty_struct *tty, struct file *file,
 727                uint cmd, ulong arg)
 728 {
 729         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 730         int error;
 731         int retval;
 732
 733         DBF_TEXT(trace, 4, __FUNCTION__);
 734         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_ioctl"))
 735                 return -ENODEV;
 736         if (tty->flags & (1 << TTY_IO_ERROR))
 737                 return -EIO;
 738         switch (cmd) {
 739                 case TCSBRK:   /* SVID version: non-zero arg --> no break */
 740 #ifdef CTC_DEBUG_MODEM_IOCTL
 741                         printk(KERN_DEBUG "%s%d ioctl TCSBRK\n", CTC_TTY_NAME, info->line);
 742 #endif
 743                         retval = tty_check_change(tty);
 744                         if (retval)
 745                                 return retval;
 746                         tty_wait_until_sent(tty, 0);
 747                         return 0;
 748                 case TCSBRKP:  /* support for POSIX tcsendbreak() */
 749 #ifdef CTC_DEBUG_MODEM_IOCTL
 750                         printk(KERN_DEBUG "%s%d ioctl TCSBRKP\n", CTC_TTY_NAME, info->line);
 751 #endif
 752                         retval = tty_check_change(tty);
 753                         if (retval)
 754                                 return retval;
 755                         tty_wait_until_sent(tty, 0);
 756                         return 0;
 757                 case TIOCGSOFTCAR:
 758 #ifdef CTC_DEBUG_MODEM_IOCTL
 759                         printk(KERN_DEBUG "%s%d ioctl TIOCGSOFTCAR\n", CTC_TTY_NAME,
 760                                info->line);
 761 #endif
 762                         error = put_user(C_CLOCAL(tty) ? 1 : 0, (ulong __user *) arg);
 763                         return error;
 764                 case TIOCSSOFTCAR:
 765 #ifdef CTC_DEBUG_MODEM_IOCTL
 766                         printk(KERN_DEBUG "%s%d ioctl TIOCSSOFTCAR\n", CTC_TTY_NAME,
 767                                info->line);
 768 #endif
 769                         error = get_user(arg, (ulong __user *) arg);
 770                         if (error)
 771                                 return error;
 772                         tty->termios->c_cflag =
 773                             ((tty->termios->c_cflag & ~CLOCAL) |
 774                              (arg ? CLOCAL : 0));
 775                         return 0;
 776                 case TIOCSERGETLSR:     /* Get line status register */
 777 #ifdef CTC_DEBUG_MODEM_IOCTL
 778                         printk(KERN_DEBUG "%s%d ioctl TIOCSERGETLSR\n", CTC_TTY_NAME,
 779                                info->line);
 780 #endif
 781                         if (access_ok(VERIFY_WRITE, (void __user *) arg, sizeof(uint)))
 782                                 return ctc_tty_get_lsr_info(info, (uint __user *) arg);
 783                         else
 784                                 return -EFAULT;
 785                 default:
 786 #ifdef CTC_DEBUG_MODEM_IOCTL
 787                         printk(KERN_DEBUG "UNKNOWN ioctl 0x%08x on %s%d\n", cmd,
 788                                CTC_TTY_NAME, info->line);
 789 #endif
 790                         return -ENOIOCTLCMD;
 791         }
 792         return 0;
 793 }
 794
 795 static void
 796 ctc_tty_set_termios(struct tty_struct *tty, struct termios *old_termios)
 797 {
 798         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 799         unsigned int cflag = tty->termios->c_cflag;
 800
 801         DBF_TEXT(trace, 4, __FUNCTION__);
 802         ctc_tty_change_speed(info);
 803
 804         /* Handle transition to B0 */
 805         if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD)) {
 806                 info->mcr &= ~(UART_MCR_DTR|UART_MCR_RTS);
 807                 ctc_tty_transmit_status(info);
 808         }
 809
 810         /* Handle transition from B0 to other */
 811         if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
 812                 info->mcr |= UART_MCR_DTR;
 813                 if (!(tty->termios->c_cflag & CRTSCTS) ||
 814                     !test_bit(TTY_THROTTLED, &tty->flags)) {
 815                         info->mcr |= UART_MCR_RTS;
 816                 }
 817                 ctc_tty_transmit_status(info);
 818         }
 819
 820         /* Handle turning off CRTSCTS */
 821         if ((old_termios->c_cflag & CRTSCTS) &&
 822             !(tty->termios->c_cflag & CRTSCTS))
 823                 tty->hw_stopped = 0;
 824 }
 825
 826 /*
 827  * ------------------------------------------------------------
 828  * ctc_tty_open() and friends
 829  * ------------------------------------------------------------
 830  */
 831 static int
 832 ctc_tty_block_til_ready(struct tty_struct *tty, struct file *filp, ctc_tty_info *info)
 833 {
 834         DECLARE_WAITQUEUE(wait, NULL);
 835         int do_clocal = 0;
 836         unsigned long flags;
 837         int retval;
 838
 839         DBF_TEXT(trace, 4, __FUNCTION__);
 840         /*
 841          * If the device is in the middle of being closed, then block
 842          * until it's done, and then try again.
 843          */
 844         if (tty_hung_up_p(filp) ||
 845             (info->flags & CTC_ASYNC_CLOSING)) {
 846                 if (info->flags & CTC_ASYNC_CLOSING)
 847                         wait_event(info->close_wait,
 848                                    !(info->flags & CTC_ASYNC_CLOSING));
 849 #ifdef MODEM_DO_RESTART
 850                 if (info->flags & CTC_ASYNC_HUP_NOTIFY)
 851                         return -EAGAIN;
 852                 else
 853                         return -ERESTARTSYS;
 854 #else
 855                 return -EAGAIN;
 856 #endif
 857         }
 858         /*
 859          * If non-blocking mode is set, then make the check up front
 860          * and then exit.
 861          */
 862         if ((filp->f_flags & O_NONBLOCK) ||
 863             (tty->flags & (1 << TTY_IO_ERROR))) {
 864                 info->flags |= CTC_ASYNC_NORMAL_ACTIVE;
 865                 return 0;
 866         }
 867         if (tty->termios->c_cflag & CLOCAL)
 868                 do_clocal = 1;
 869         /*
 870          * Block waiting for the carrier detect and the line to become
 871          * free (i.e., not in use by the callout).  While we are in
 872          * this loop, info->count is dropped by one, so that
 873          * ctc_tty_close() knows when to free things.  We restore it upon
 874          * exit, either normal or abnormal.
 875          */
 876         retval = 0;
 877         add_wait_queue(&info->open_wait, &wait);
 878 #ifdef CTC_DEBUG_MODEM_OPEN
 879         printk(KERN_DEBUG "ctc_tty_block_til_ready before block: %s%d, count = %d\n",
 880                CTC_TTY_NAME, info->line, info->count);
 881 #endif
 882         spin_lock_irqsave(&ctc_tty_lock, flags);
 883         if (!(tty_hung_up_p(filp)))
 884                 info->count--;
 885         spin_unlock_irqrestore(&ctc_tty_lock, flags);
 886         info->blocked_open++;
 887         while (1) {
 888                 set_current_state(TASK_INTERRUPTIBLE);
 889                 if (tty_hung_up_p(filp) ||
 890                     !(info->flags & CTC_ASYNC_INITIALIZED)) {
 891 #ifdef MODEM_DO_RESTART
 892                         if (info->flags & CTC_ASYNC_HUP_NOTIFY)
 893                                 retval = -EAGAIN;
 894                         else
 895                                 retval = -ERESTARTSYS;
 896 #else
 897                         retval = -EAGAIN;
 898 #endif
 899                         break;
 900                 }
 901                 if (!(info->flags & CTC_ASYNC_CLOSING) &&
 902                     (do_clocal || (info->msr & UART_MSR_DCD))) {
 903                         break;
 904                 }
 905                 if (signal_pending(current)) {
 906                         retval = -ERESTARTSYS;
 907                         break;
 908                 }
 909 #ifdef CTC_DEBUG_MODEM_OPEN
 910                 printk(KERN_DEBUG "ctc_tty_block_til_ready blocking: %s%d, count = %d\n",
 911                        CTC_TTY_NAME, info->line, info->count);
 912 #endif
 913                 schedule();
 914         }
 915         current->state = TASK_RUNNING;
 916         remove_wait_queue(&info->open_wait, &wait);
 917         if (!tty_hung_up_p(filp))
 918                 info->count++;
 919         info->blocked_open--;
 920 #ifdef CTC_DEBUG_MODEM_OPEN
 921         printk(KERN_DEBUG "ctc_tty_block_til_ready after blocking: %s%d, count = %d\n",
 922                CTC_TTY_NAME, info->line, info->count);
 923 #endif
 924         if (retval)
 925                 return retval;
 926         info->flags |= CTC_ASYNC_NORMAL_ACTIVE;
 927         return 0;
 928 }
 929
 930 /*
 931  * This routine is called whenever a serial port is opened.  It
 932  * enables interrupts for a serial port, linking in its async structure into
 933  * the IRQ chain.   It also performs the serial-specific
 934  * initialization for the tty structure.
 935  */
 936 static int
 937 ctc_tty_open(struct tty_struct *tty, struct file *filp)
 938 {
 939         ctc_tty_info *info;
 940         unsigned long saveflags;
 941         int retval,
 942          line;
 943
 944         DBF_TEXT(trace, 3, __FUNCTION__);
 945         line = tty->index;
 946         if (line < 0 || line > CTC_TTY_MAX_DEVICES)
 947                 return -ENODEV;
 948         info = &driver->info[line];
 949         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_open"))
 950                 return -ENODEV;
 951         if (!info->netdev)
 952                 return -ENODEV;
 953 #ifdef CTC_DEBUG_MODEM_OPEN
 954         printk(KERN_DEBUG "ctc_tty_open %s, count = %d\n", tty->name,
 955                info->count);
 956 #endif
 957         spin_lock_irqsave(&ctc_tty_lock, saveflags);
 958         info->count++;
 959         tty->driver_data = info;
 960         info->tty = tty;
 961         spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
 962         /*
 963          * Start up serial port
 964          */
 965         retval = ctc_tty_startup(info);
 966         if (retval) {
 967 #ifdef CTC_DEBUG_MODEM_OPEN
 968                 printk(KERN_DEBUG "ctc_tty_open return after startup\n");
 969 #endif
 970                 return retval;
 971         }
 972         retval = ctc_tty_block_til_ready(tty, filp, info);
 973         if (retval) {
 974 #ifdef CTC_DEBUG_MODEM_OPEN
 975                 printk(KERN_DEBUG "ctc_tty_open return after ctc_tty_block_til_ready \n");
 976 #endif
 977                 return retval;
 978         }
 979 #ifdef CTC_DEBUG_MODEM_OPEN
 980         printk(KERN_DEBUG "ctc_tty_open %s successful...\n", tty->name);
 981 #endif
 982         return 0;
 983 }
 984
 985 static void
 986 ctc_tty_close(struct tty_struct *tty, struct file *filp)
 987 {
 988         ctc_tty_info *info = (ctc_tty_info *) tty->driver_data;
 989         ulong flags;
 990         ulong timeout;
 991         DBF_TEXT(trace, 3, __FUNCTION__);
 992         if (!info || ctc_tty_paranoia_check(info, tty->name, "ctc_tty_close"))
 993                 return;
 994         spin_lock_irqsave(&ctc_tty_lock, flags);
 995         if (tty_hung_up_p(filp)) {
 996                 spin_unlock_irqrestore(&ctc_tty_lock, flags);
 997 #ifdef CTC_DEBUG_MODEM_OPEN
 998                 printk(KERN_DEBUG "ctc_tty_close return after tty_hung_up_p\n");
 999 #endif
1000                 return;
1001         }
1002         if ((tty->count == 1) && (info->count != 1)) {
1003                 /*
1004                  * Uh, oh.  tty->count is 1, which means that the tty
1005                  * structure will be freed.  Info->count should always
1006                  * be one in these conditions.  If it's greater than
1007                  * one, we've got real problems, since it means the
1008                  * serial port won't be shutdown.
1009                  */
1010                 printk(KERN_ERR "ctc_tty_close: bad port count; tty->count is 1, "
1011                        "info->count is %d\n", info->count);
1012                 info->count = 1;
1013         }
1014         if (--info->count < 0) {
1015                 printk(KERN_ERR "ctc_tty_close: bad port count for %s%d: %d\n",
1016                        CTC_TTY_NAME, info->line, info->count);
1017                 info->count = 0;
1018         }
1019         if (info->count) {
1020                 local_irq_restore(flags);
1021 #ifdef CTC_DEBUG_MODEM_OPEN
1022                 printk(KERN_DEBUG "ctc_tty_close after info->count != 0\n");
1023 #endif
1024                 return;
1025         }
1026         info->flags |= CTC_ASYNC_CLOSING;
1027         tty->closing = 1;
1028         /*
1029          * At this point we stop accepting input.  To do this, we
1030          * disable the receive line status interrupts, and tell the
1031          * interrupt driver to stop checking the data ready bit in the
1032          * line status register.
1033          */
1034         if (info->flags & CTC_ASYNC_INITIALIZED) {
1035                 tty_wait_until_sent(tty, 30*HZ); /* 30 seconds timeout */
1036                 /*
1037                  * Before we drop DTR, make sure the UART transmitter
1038                  * has completely drained; this is especially
1039                  * important if there is a transmit FIFO!
1040                  */
1041                 timeout = jiffies + HZ;
1042                 while (!(info->lsr & UART_LSR_TEMT)) {
1043                         spin_unlock_irqrestore(&ctc_tty_lock, flags);
1044                         msleep(500);
1045                         spin_lock_irqsave(&ctc_tty_lock, flags);
1046                         if (time_after(jiffies,timeout))
1047                                 break;
1048                 }
1049         }
1050         ctc_tty_shutdown(info);
1051         if (tty->driver->flush_buffer) {
1052                 skb_queue_purge(&info->tx_queue);
1053                 info->lsr |= UART_LSR_TEMT;
1054         }
1055         tty_ldisc_flush(tty);
1056         info->tty = 0;
1057         tty->closing = 0;
1058         if (info->blocked_open) {
1059                 msleep_interruptible(500);
1060                 wake_up_interruptible(&info->open_wait);
1061         }
1062         info->flags &= ~(CTC_ASYNC_NORMAL_ACTIVE | CTC_ASYNC_CLOSING);
1063         wake_up_interruptible(&info->close_wait);
1064         spin_unlock_irqrestore(&ctc_tty_lock, flags);
1065 #ifdef CTC_DEBUG_MODEM_OPEN
1066         printk(KERN_DEBUG "ctc_tty_close normal exit\n");
1067 #endif
1068 }
1069
1070 /*
1071  * ctc_tty_hangup() --- called by tty_hangup() when a hangup is signaled.
1072  */
1073 static void
1074 ctc_tty_hangup(struct tty_struct *tty)
1075 {
1076         ctc_tty_info *info = (ctc_tty_info *)tty->driver_data;
1077         unsigned long saveflags;
1078         DBF_TEXT(trace, 3, __FUNCTION__);
1079         if (ctc_tty_paranoia_check(info, tty->name, "ctc_tty_hangup"))
1080                 return;
1081         ctc_tty_shutdown(info);
1082         info->count = 0;
1083         info->flags &= ~CTC_ASYNC_NORMAL_ACTIVE;
1084         spin_lock_irqsave(&ctc_tty_lock, saveflags);
1085         info->tty = 0;
1086         spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
1087         wake_up_interruptible(&info->open_wait);
1088 }
1089
1090
1091 /*
1092  * For all online tty's, try sending data to
1093  * the lower levels.
1094  */
1095 static void
1096 ctc_tty_task(unsigned long arg)
1097 {
1098         ctc_tty_info *info = (void *)arg;
1099         unsigned long saveflags;
1100         int again;
1101
1102         DBF_TEXT(trace, 3, __FUNCTION__);
1103         spin_lock_irqsave(&ctc_tty_lock, saveflags);
1104         if ((!ctc_tty_shuttingdown) && info) {
1105                 again = ctc_tty_tint(info);
1106                 if (!again)
1107                         info->lsr |= UART_LSR_TEMT;
1108                 again |= ctc_tty_readmodem(info);
1109                 if (again) {
1110                         tasklet_schedule(&info->tasklet);
1111                 }
1112         }
1113         spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
1114 }
1115
1116 static struct tty_operations ctc_ops = {
1117         .open = ctc_tty_open,
1118         .close = ctc_tty_close,
1119         .write = ctc_tty_write,
1120         .flush_chars = ctc_tty_flush_chars,
1121         .write_room = ctc_tty_write_room,
1122         .chars_in_buffer = ctc_tty_chars_in_buffer,
1123         .flush_buffer = ctc_tty_flush_buffer,
1124         .ioctl = ctc_tty_ioctl,
1125         .throttle = ctc_tty_throttle,
1126         .unthrottle = ctc_tty_unthrottle,
1127         .set_termios = ctc_tty_set_termios,
1128         .hangup = ctc_tty_hangup,
1129         .tiocmget = ctc_tty_tiocmget,
1130         .tiocmset = ctc_tty_tiocmset,
1131 };
1132
1133 int
1134 ctc_tty_init(void)
1135 {
1136         int i;
1137         ctc_tty_info *info;
1138         struct tty_driver *device;
1139
1140         DBF_TEXT(trace, 2, __FUNCTION__);
1141         driver = kmalloc(sizeof(ctc_tty_driver), GFP_KERNEL);
1142         if (driver == NULL) {
1143                 printk(KERN_WARNING "Out of memory in ctc_tty_modem_init\n");
1144                 return -ENOMEM;
1145         }
1146         memset(driver, 0, sizeof(ctc_tty_driver));
1147         device = alloc_tty_driver(CTC_TTY_MAX_DEVICES);
1148         if (!device) {
1149                 kfree(driver);
1150                 printk(KERN_WARNING "Out of memory in ctc_tty_modem_init\n");
1151                 return -ENOMEM;
1152         }
1153
1154         device->devfs_name = "ctc/" CTC_TTY_NAME;
1155         device->name = CTC_TTY_NAME;
1156         device->major = CTC_TTY_MAJOR;
1157         device->minor_start = 0;
1158         device->type = TTY_DRIVER_TYPE_SERIAL;
1159         device->subtype = SERIAL_TYPE_NORMAL;
1160         device->init_termios = tty_std_termios;
1161         device->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1162         device->flags = TTY_DRIVER_REAL_RAW;
1163         device->driver_name = "ctc_tty",
1164         tty_set_operations(device, &ctc_ops);
1165         if (tty_register_driver(device)) {
1166                 printk(KERN_WARNING "ctc_tty: Couldn't register serial-device\n");
1167                 put_tty_driver(device);
1168                 kfree(driver);
1169                 return -1;
1170         }
1171         driver->ctc_tty_device = device;
1172         for (i = 0; i < CTC_TTY_MAX_DEVICES; i++) {
1173                 info = &driver->info[i];
1174                 init_MUTEX(&info->write_sem);
1175                 tasklet_init(&info->tasklet, ctc_tty_task,
1176                                 (unsigned long) info);
1177                 info->magic = CTC_ASYNC_MAGIC;
1178                 info->line = i;
1179                 info->tty = 0;
1180                 info->count = 0;
1181                 info->blocked_open = 0;
1182                 init_waitqueue_head(&info->open_wait);
1183                 init_waitqueue_head(&info->close_wait);
1184                 skb_queue_head_init(&info->tx_queue);
1185                 skb_queue_head_init(&info->rx_queue);
1186                 init_timer(&info->stoptimer);
1187                 info->stoptimer.function = ctc_tty_stopdev;
1188                 info->stoptimer.data = (unsigned long)info;
1189                 info->mcr = UART_MCR_RTS;
1190         }
1191         return 0;
1192 }
1193
1194 int
1195 ctc_tty_register_netdev(struct net_device *dev) {
1196         int ttynum;
1197         char *err;
1198         char *p;
1199
1200         DBF_TEXT(trace, 2, __FUNCTION__);
1201         if ((!dev) || (!dev->name)) {
1202                 printk(KERN_WARNING
1203                        "ctc_tty_register_netdev called "
1204                        "with NULL dev or NULL dev-name\n");
1205                 return -1;
1206         }
1207
1208         /*
1209          *      If the name is a format string the caller wants us to
1210          *      do a name allocation : format string must end with %d
1211          */
1212         if (strchr(dev->name, '%'))
1213         {
1214                 int err = dev_alloc_name(dev, dev->name);       // dev->name is changed by this
1215                 if (err < 0) {
1216                         printk(KERN_DEBUG "dev_alloc returned error %d\n", err);
1217                         return err;
1218                 }
1219
1220         }
1221
1222         for (p = dev->name; p && ((*p < '0') || (*p > '9')); p++);
1223         ttynum = simple_strtoul(p, &err, 0);
1224         if ((ttynum < 0) || (ttynum >= CTC_TTY_MAX_DEVICES) ||
1225             (err && *err)) {
1226                 printk(KERN_WARNING
1227                        "ctc_tty_register_netdev called "
1228                        "with number in name '%s'\n", dev->name);
1229                 return -1;
1230         }
1231         if (driver->info[ttynum].netdev) {
1232                 printk(KERN_WARNING
1233                        "ctc_tty_register_netdev called "
1234                        "for already registered device '%s'\n",
1235                        dev->name);
1236                 return -1;
1237         }
1238         driver->info[ttynum].netdev = dev;
1239         return 0;
1240 }
1241
1242 void
1243 ctc_tty_unregister_netdev(struct net_device *dev) {
1244         int i;
1245         unsigned long saveflags;
1246         ctc_tty_info *info = NULL;
1247
1248         DBF_TEXT(trace, 2, __FUNCTION__);
1249         spin_lock_irqsave(&ctc_tty_lock, saveflags);
1250         for (i = 0; i < CTC_TTY_MAX_DEVICES; i++)
1251                 if (driver->info[i].netdev == dev) {
1252                         info = &driver->info[i];
1253                         break;
1254                 }
1255         if (info) {
1256                 info->netdev = NULL;
1257                 skb_queue_purge(&info->tx_queue);
1258                 skb_queue_purge(&info->rx_queue);
1259         }
1260         spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
1261 }
1262
1263 void
1264 ctc_tty_cleanup(void) {
1265         unsigned long saveflags;
1266
1267         DBF_TEXT(trace, 2, __FUNCTION__);
1268         spin_lock_irqsave(&ctc_tty_lock, saveflags);
1269         ctc_tty_shuttingdown = 1;
1270         spin_unlock_irqrestore(&ctc_tty_lock, saveflags);
1271         tty_unregister_driver(driver->ctc_tty_device);
1272         put_tty_driver(driver->ctc_tty_device);
1273         kfree(driver);
1274         driver = NULL;
1275 }