drivers/char/generic_serial.c

   1 /*
   2  *  generic_serial.c
   3  *
   4  *  Copyright (C) 1998/1999 R.E.Wolff@BitWizard.nl
   5  *
   6  *  written for the SX serial driver.
   7  *     Contains the code that should be shared over all the serial drivers.
   8  *
   9  *  Credit for the idea to do it this way might go to Alan Cox.
  10  *
  11  *
  12  *  Version 0.1 -- December, 1998. Initial version.
  13  *  Version 0.2 -- March, 1999.    Some more routines. Bugfixes. Etc.
  14  *  Version 0.5 -- August, 1999.   Some more fixes. Reformat for Linus.
  15  *
  16  *  BitWizard is actively maintaining this file. We sometimes find
  17  *  that someone submitted changes to this file. We really appreciate
  18  *  your help, but please submit changes through us. We're doing our
  19  *  best to be responsive.  -- REW
  20  * */
  21
  22 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/tty.h>
  25 #include <linux/serial.h>
  26 #include <linux/mm.h>
  27 #include <linux/generic_serial.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/tty_flip.h>
  30 #include <linux/delay.h>
  31 #include <asm/uaccess.h>
  32
  33 #define DEBUG
  34
  35 static int gs_debug;
  36
  37 #ifdef DEBUG
  38 #define gs_dprintk(f, str...) if (gs_debug & f) printk (str)
  39 #else
  40 #define gs_dprintk(f, str...) /* nothing */
  41 #endif
  42
  43 #define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __func__)
  44 #define func_exit()  gs_dprintk (GS_DEBUG_FLOW, "gs: exit  %s\n", __func__)
  45
  46 #define RS_EVENT_WRITE_WAKEUP   1
  47
  48 module_param(gs_debug, int, 0644);
  49
  50
  51 int gs_put_char(struct tty_struct * tty, unsigned char ch)
  52 {
  53         struct gs_port *port;
  54
  55         func_enter ();
  56
  57         port = tty->driver_data;
  58
  59         if (!port) return 0;
  60
  61         if (! (port->port.flags & ASYNC_INITIALIZED)) return 0;
  62
  63         /* Take a lock on the serial tranmit buffer! */
  64         mutex_lock(& port->port_write_mutex);
  65
  66         if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
  67                 /* Sorry, buffer is full, drop character. Update statistics???? -- REW */
  68                 mutex_unlock(&port->port_write_mutex);
  69                 return 0;
  70         }
  71
  72         port->xmit_buf[port->xmit_head++] = ch;
  73         port->xmit_head &= SERIAL_XMIT_SIZE - 1;
  74         port->xmit_cnt++;  /* Characters in buffer */
  75
  76         mutex_unlock(&port->port_write_mutex);
  77         func_exit ();
  78         return 1;
  79 }
  80
  81
  82 /*
  83 > Problems to take into account are:
  84 >       -1- Interrupts that empty part of the buffer.
  85 >       -2- page faults on the access to userspace.
  86 >       -3- Other processes that are also trying to do a "write".
  87 */
  88
  89 int gs_write(struct tty_struct * tty,
  90                     const unsigned char *buf, int count)
  91 {
  92         struct gs_port *port;
  93         int c, total = 0;
  94         int t;
  95
  96         func_enter ();
  97
  98         port = tty->driver_data;
  99
 100         if (!port) return 0;
 101
 102         if (! (port->port.flags & ASYNC_INITIALIZED))
 103                 return 0;
 104
 105         /* get exclusive "write" access to this port (problem 3) */
 106         /* This is not a spinlock because we can have a disk access (page
 107                  fault) in copy_from_user */
 108         mutex_lock(& port->port_write_mutex);
 109
 110         while (1) {
 111
 112                 c = count;
 113
 114                 /* This is safe because we "OWN" the "head". Noone else can
 115                    change the "head": we own the port_write_mutex. */
 116                 /* Don't overrun the end of the buffer */
 117                 t = SERIAL_XMIT_SIZE - port->xmit_head;
 118                 if (t < c) c = t;
 119
 120                 /* This is safe because the xmit_cnt can only decrease. This
 121                    would increase "t", so we might copy too little chars. */
 122                 /* Don't copy past the "head" of the buffer */
 123                 t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
 124                 if (t < c) c = t;
 125
 126                 /* Can't copy more? break out! */
 127                 if (c <= 0) break;
 128
 129                 memcpy (port->xmit_buf + port->xmit_head, buf, c);
 130
 131                 port -> xmit_cnt += c;
 132                 port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
 133                 buf += c;
 134                 count -= c;
 135                 total += c;
 136         }
 137         mutex_unlock(& port->port_write_mutex);
 138
 139         gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n",
 140                     (port->port.flags & GS_TX_INTEN)?"enabled": "disabled");
 141
 142         if (port->xmit_cnt &&
 143             !tty->stopped &&
 144             !tty->hw_stopped &&
 145             !(port->port.flags & GS_TX_INTEN)) {
 146                 port->port.flags |= GS_TX_INTEN;
 147                 port->rd->enable_tx_interrupts (port);
 148         }
 149         func_exit ();
 150         return total;
 151 }
 152
 153
 154
 155 int gs_write_room(struct tty_struct * tty)
 156 {
 157         struct gs_port *port = tty->driver_data;
 158         int ret;
 159
 160         func_enter ();
 161         ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
 162         if (ret < 0)
 163                 ret = 0;
 164         func_exit ();
 165         return ret;
 166 }
 167
 168
 169 int gs_chars_in_buffer(struct tty_struct *tty)
 170 {
 171         struct gs_port *port = tty->driver_data;
 172         func_enter ();
 173
 174         func_exit ();
 175         return port->xmit_cnt;
 176 }
 177
 178
 179 static int gs_real_chars_in_buffer(struct tty_struct *tty)
 180 {
 181         struct gs_port *port;
 182         func_enter ();
 183
 184         port = tty->driver_data;
 185
 186         if (!port->rd) return 0;
 187         if (!port->rd->chars_in_buffer) return 0;
 188
 189         func_exit ();
 190         return port->xmit_cnt + port->rd->chars_in_buffer (port);
 191 }
 192
 193
 194 static int gs_wait_tx_flushed (void * ptr, unsigned long timeout)
 195 {
 196         struct gs_port *port = ptr;
 197         unsigned long end_jiffies;
 198         int jiffies_to_transmit, charsleft = 0, rv = 0;
 199         int rcib;
 200
 201         func_enter();
 202
 203         gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
 204         if (port) {
 205                 gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n",
 206                 port->xmit_cnt, port->xmit_buf, port->port.tty);
 207         }
 208
 209         if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
 210                 gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
 211                 func_exit();
 212                 return -EINVAL;  /* This is an error which we don't know how to handle. */
 213         }
 214
 215         rcib = gs_real_chars_in_buffer(port->port.tty);
 216
 217         if(rcib <= 0) {
 218                 gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
 219                 func_exit();
 220                 return rv;
 221         }
 222         /* stop trying: now + twice the time it would normally take +  seconds */
 223         if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
 224         end_jiffies  = jiffies;
 225         if (timeout !=  MAX_SCHEDULE_TIMEOUT)
 226                 end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
 227         end_jiffies += timeout;
 228
 229         gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n",
 230                     jiffies, end_jiffies, end_jiffies-jiffies);
 231
 232         /* the expression is actually jiffies < end_jiffies, but that won't
 233            work around the wraparound. Tricky eh? */
 234         while ((charsleft = gs_real_chars_in_buffer (port->port.tty)) &&
 235                 time_after (end_jiffies, jiffies)) {
 236                 /* Units check:
 237                    chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
 238                    check! */
 239
 240                 charsleft += 16; /* Allow 16 chars more to be transmitted ... */
 241                 jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
 242                 /*                                ^^^ Round up.... */
 243                 if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;
 244
 245                 gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
 246                             "(%d chars).\n", jiffies_to_transmit, charsleft);
 247
 248                 msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
 249                 if (signal_pending (current)) {
 250                         gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: ");
 251                         rv = -EINTR;
 252                         break;
 253                 }
 254         }
 255
 256         gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft);
 257         set_current_state (TASK_RUNNING);
 258
 259         func_exit();
 260         return rv;
 261 }
 262
 263
 264
 265 void gs_flush_buffer(struct tty_struct *tty)
 266 {
 267         struct gs_port *port;
 268         unsigned long flags;
 269
 270         func_enter ();
 271
 272         port = tty->driver_data;
 273
 274         if (!port) return;
 275
 276         /* XXX Would the write semaphore do? */
 277         spin_lock_irqsave (&port->driver_lock, flags);
 278         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 279         spin_unlock_irqrestore (&port->driver_lock, flags);
 280
 281         tty_wakeup(tty);
 282         func_exit ();
 283 }
 284
 285
 286 void gs_flush_chars(struct tty_struct * tty)
 287 {
 288         struct gs_port *port;
 289
 290         func_enter ();
 291
 292         port = tty->driver_data;
 293
 294         if (!port) return;
 295
 296         if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
 297             !port->xmit_buf) {
 298                 func_exit ();
 299                 return;
 300         }
 301
 302         /* Beats me -- REW */
 303         port->port.flags |= GS_TX_INTEN;
 304         port->rd->enable_tx_interrupts (port);
 305         func_exit ();
 306 }
 307
 308
 309 void gs_stop(struct tty_struct * tty)
 310 {
 311         struct gs_port *port;
 312
 313         func_enter ();
 314
 315         port = tty->driver_data;
 316
 317         if (!port) return;
 318
 319         if (port->xmit_cnt &&
 320             port->xmit_buf &&
 321             (port->port.flags & GS_TX_INTEN) ) {
 322                 port->port.flags &= ~GS_TX_INTEN;
 323                 port->rd->disable_tx_interrupts (port);
 324         }
 325         func_exit ();
 326 }
 327
 328
 329 void gs_start(struct tty_struct * tty)
 330 {
 331         struct gs_port *port;
 332
 333         port = tty->driver_data;
 334
 335         if (!port) return;
 336
 337         if (port->xmit_cnt &&
 338             port->xmit_buf &&
 339             !(port->port.flags & GS_TX_INTEN) ) {
 340                 port->port.flags |= GS_TX_INTEN;
 341                 port->rd->enable_tx_interrupts (port);
 342         }
 343         func_exit ();
 344 }
 345
 346
 347 static void gs_shutdown_port (struct gs_port *port)
 348 {
 349         unsigned long flags;
 350
 351         func_enter();
 352
 353         if (!port) return;
 354
 355         if (!(port->port.flags & ASYNC_INITIALIZED))
 356                 return;
 357
 358         spin_lock_irqsave(&port->driver_lock, flags);
 359
 360         if (port->xmit_buf) {
 361                 free_page((unsigned long) port->xmit_buf);
 362                 port->xmit_buf = NULL;
 363         }
 364
 365         if (port->port.tty)
 366                 set_bit(TTY_IO_ERROR, &port->port.tty->flags);
 367
 368         port->rd->shutdown_port (port);
 369
 370         port->port.flags &= ~ASYNC_INITIALIZED;
 371         spin_unlock_irqrestore(&port->driver_lock, flags);
 372
 373         func_exit();
 374 }
 375
 376
 377 void gs_hangup(struct tty_struct *tty)
 378 {
 379         struct gs_port   *port;
 380
 381         func_enter ();
 382
 383         port = tty->driver_data;
 384         tty = port->port.tty;
 385         if (!tty)
 386                 return;
 387
 388         gs_shutdown_port (port);
 389         port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
 390         port->port.tty = NULL;
 391         port->port.count = 0;
 392
 393         wake_up_interruptible(&port->port.open_wait);
 394         func_exit ();
 395 }
 396
 397
 398 int gs_block_til_ready(void *port_, struct file * filp)
 399 {
 400         struct gs_port *port = port_;
 401         DECLARE_WAITQUEUE(wait, current);
 402         int    retval;
 403         int    do_clocal = 0;
 404         int    CD;
 405         struct tty_struct *tty;
 406         unsigned long flags;
 407
 408         func_enter ();
 409
 410         if (!port) return 0;
 411
 412         tty = port->port.tty;
 413
 414         gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
 415         /*
 416          * If the device is in the middle of being closed, then block
 417          * until it's done, and then try again.
 418          */
 419         if (tty_hung_up_p(filp) || port->port.flags & ASYNC_CLOSING) {
 420                 interruptible_sleep_on(&port->port.close_wait);
 421                 if (port->port.flags & ASYNC_HUP_NOTIFY)
 422                         return -EAGAIN;
 423                 else
 424                         return -ERESTARTSYS;
 425         }
 426
 427         gs_dprintk (GS_DEBUG_BTR, "after hung up\n");
 428
 429         /*
 430          * If non-blocking mode is set, or the port is not enabled,
 431          * then make the check up front and then exit.
 432          */
 433         if ((filp->f_flags & O_NONBLOCK) ||
 434             (tty->flags & (1 << TTY_IO_ERROR))) {
 435                 port->port.flags |= ASYNC_NORMAL_ACTIVE;
 436                 return 0;
 437         }
 438
 439         gs_dprintk (GS_DEBUG_BTR, "after nonblock\n");
 440
 441         if (C_CLOCAL(tty))
 442                 do_clocal = 1;
 443
 444         /*
 445          * Block waiting for the carrier detect and the line to become
 446          * free (i.e., not in use by the callout).  While we are in
 447          * this loop, port->port.count is dropped by one, so that
 448          * rs_close() knows when to free things.  We restore it upon
 449          * exit, either normal or abnormal.
 450          */
 451         retval = 0;
 452
 453         add_wait_queue(&port->port.open_wait, &wait);
 454
 455         gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
 456         spin_lock_irqsave(&port->driver_lock, flags);
 457         if (!tty_hung_up_p(filp)) {
 458                 port->port.count--;
 459         }
 460         spin_unlock_irqrestore(&port->driver_lock, flags);
 461         port->port.blocked_open++;
 462         while (1) {
 463                 CD = port->rd->get_CD (port);
 464                 gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
 465                 set_current_state (TASK_INTERRUPTIBLE);
 466                 if (tty_hung_up_p(filp) ||
 467                     !(port->port.flags & ASYNC_INITIALIZED)) {
 468                         if (port->port.flags & ASYNC_HUP_NOTIFY)
 469                                 retval = -EAGAIN;
 470                         else
 471                                 retval = -ERESTARTSYS;
 472                         break;
 473                 }
 474                 if (!(port->port.flags & ASYNC_CLOSING) &&
 475                     (do_clocal || CD))
 476                         break;
 477                 gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
 478                 (int)signal_pending (current), *(long*)(&current->blocked));
 479                 if (signal_pending(current)) {
 480                         retval = -ERESTARTSYS;
 481                         break;
 482                 }
 483                 schedule();
 484         }
 485         gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
 486                     port->port.blocked_open);
 487         set_current_state (TASK_RUNNING);
 488         remove_wait_queue(&port->port.open_wait, &wait);
 489         if (!tty_hung_up_p(filp)) {
 490                 port->port.count++;
 491         }
 492         port->port.blocked_open--;
 493         if (retval)
 494                 return retval;
 495
 496         port->port.flags |= ASYNC_NORMAL_ACTIVE;
 497         func_exit ();
 498         return 0;
 499 }
 500
 501
 502 void gs_close(struct tty_struct * tty, struct file * filp)
 503 {
 504         unsigned long flags;
 505         struct gs_port *port;
 506
 507         func_enter ();
 508
 509         port = (struct gs_port *) tty->driver_data;
 510
 511         if (!port) return;
 512
 513         if (!port->port.tty) {
 514                 /* This seems to happen when this is called from vhangup. */
 515                 gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->port.tty is NULL\n");
 516                 port->port.tty = tty;
 517         }
 518
 519         spin_lock_irqsave(&port->driver_lock, flags);
 520
 521         if (tty_hung_up_p(filp)) {
 522                 spin_unlock_irqrestore(&port->driver_lock, flags);
 523                 if (port->rd->hungup)
 524                         port->rd->hungup (port);
 525                 func_exit ();
 526                 return;
 527         }
 528
 529         if ((tty->count == 1) && (port->port.count != 1)) {
 530                 printk(KERN_ERR "gs: gs_close port %p: bad port count;"
 531                        " tty->count is 1, port count is %d\n", port, port->port.count);
 532                 port->port.count = 1;
 533         }
 534         if (--port->port.count < 0) {
 535                 printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->port.count);
 536                 port->port.count = 0;
 537         }
 538
 539         if (port->port.count) {
 540                 gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->port.count);
 541                 spin_unlock_irqrestore(&port->driver_lock, flags);
 542                 func_exit ();
 543                 return;
 544         }
 545         port->port.flags |= ASYNC_CLOSING;
 546
 547         /*
 548          * Now we wait for the transmit buffer to clear; and we notify
 549          * the line discipline to only process XON/XOFF characters.
 550          */
 551         tty->closing = 1;
 552         /* if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 553            tty_wait_until_sent(tty, port->closing_wait); */
 554
 555         /*
 556          * At this point we stop accepting input.  To do this, we
 557          * disable the receive line status interrupts, and tell the
 558          * interrupt driver to stop checking the data ready bit in the
 559          * line status register.
 560          */
 561
 562         port->rd->disable_rx_interrupts (port);
 563         spin_unlock_irqrestore(&port->driver_lock, flags);
 564
 565         /* close has no way of returning "EINTR", so discard return value */
 566         if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 567                 gs_wait_tx_flushed (port, port->closing_wait);
 568
 569         port->port.flags &= ~GS_ACTIVE;
 570
 571         gs_flush_buffer(tty);
 572
 573         tty_ldisc_flush(tty);
 574         tty->closing = 0;
 575
 576         port->event = 0;
 577         port->rd->close (port);
 578         port->rd->shutdown_port (port);
 579         port->port.tty = NULL;
 580
 581         if (port->port.blocked_open) {
 582                 if (port->close_delay) {
 583                         spin_unlock_irqrestore(&port->driver_lock, flags);
 584                         msleep_interruptible(jiffies_to_msecs(port->close_delay));
 585                         spin_lock_irqsave(&port->driver_lock, flags);
 586                 }
 587                 wake_up_interruptible(&port->port.open_wait);
 588         }
 589         port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
 590         wake_up_interruptible(&port->port.close_wait);
 591
 592         func_exit ();
 593 }
 594
 595
 596 void gs_set_termios (struct tty_struct * tty,
 597                      struct ktermios * old_termios)
 598 {
 599         struct gs_port *port;
 600         int baudrate, tmp, rv;
 601         struct ktermios *tiosp;
 602
 603         func_enter();
 604
 605         port = tty->driver_data;
 606
 607         if (!port) return;
 608         if (!port->port.tty) {
 609                 /* This seems to happen when this is called after gs_close. */
 610                 gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->port.tty is NULL\n");
 611                 port->port.tty = tty;
 612         }
 613
 614
 615         tiosp = tty->termios;
 616
 617         if (gs_debug & GS_DEBUG_TERMIOS) {
 618                 gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
 619         }
 620
 621         if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
 622                 if(tiosp->c_iflag != old_termios->c_iflag)  printk("c_iflag changed\n");
 623                 if(tiosp->c_oflag != old_termios->c_oflag)  printk("c_oflag changed\n");
 624                 if(tiosp->c_cflag != old_termios->c_cflag)  printk("c_cflag changed\n");
 625                 if(tiosp->c_lflag != old_termios->c_lflag)  printk("c_lflag changed\n");
 626                 if(tiosp->c_line  != old_termios->c_line)   printk("c_line changed\n");
 627                 if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
 628         }
 629
 630         baudrate = tty_get_baud_rate(tty);
 631
 632         if ((tiosp->c_cflag & CBAUD) == B38400) {
 633                 if (     (port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
 634                         baudrate = 57600;
 635                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
 636                         baudrate = 115200;
 637                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
 638                         baudrate = 230400;
 639                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
 640                         baudrate = 460800;
 641                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
 642                         baudrate = (port->baud_base / port->custom_divisor);
 643         }
 644
 645         /* I recommend using THIS instead of the mess in termios (and
 646            duplicating the above code). Next we should create a clean
 647            interface towards this variable. If your card supports arbitrary
 648            baud rates, (e.g. CD1400 or 16550 based cards) then everything
 649            will be very easy..... */
 650         port->baud = baudrate;
 651
 652         /* Two timer ticks seems enough to wakeup something like SLIP driver */
 653         /* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
 654         tmp = (baudrate / 10 / HZ) * 2;
 655
 656         if (tmp <                 0) tmp = 0;
 657         if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;
 658
 659         port->wakeup_chars = tmp;
 660
 661         /* We should really wait for the characters to be all sent before
 662            changing the settings. -- CAL */
 663         rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
 664         if (rv < 0) return /* rv */;
 665
 666         rv = port->rd->set_real_termios(port);
 667         if (rv < 0) return /* rv */;
 668
 669         if ((!old_termios ||
 670              (old_termios->c_cflag & CRTSCTS)) &&
 671             !(      tiosp->c_cflag & CRTSCTS)) {
 672                 tty->stopped = 0;
 673                 gs_start(tty);
 674         }
 675
 676 #ifdef tytso_patch_94Nov25_1726
 677         /* This "makes sense", Why is it commented out? */
 678
 679         if (!(old_termios->c_cflag & CLOCAL) &&
 680             (tty->termios->c_cflag & CLOCAL))
 681                 wake_up_interruptible(&port->gs.open_wait);
 682 #endif
 683
 684         func_exit();
 685         return /* 0 */;
 686 }
 687
 688
 689
 690 /* Must be called with interrupts enabled */
 691 int gs_init_port(struct gs_port *port)
 692 {
 693         unsigned long flags;
 694
 695         func_enter ();
 696
 697         if (port->port.flags & ASYNC_INITIALIZED) {
 698                 func_exit ();
 699                 return 0;
 700         }
 701         if (!port->xmit_buf) {
 702                 /* We may sleep in get_zeroed_page() */
 703                 unsigned long tmp;
 704
 705                 tmp = get_zeroed_page(GFP_KERNEL);
 706                 spin_lock_irqsave (&port->driver_lock, flags);
 707                 if (port->xmit_buf)
 708                         free_page (tmp);
 709                 else
 710                         port->xmit_buf = (unsigned char *) tmp;
 711                 spin_unlock_irqrestore(&port->driver_lock, flags);
 712                 if (!port->xmit_buf) {
 713                         func_exit ();
 714                         return -ENOMEM;
 715                 }
 716         }
 717
 718         spin_lock_irqsave (&port->driver_lock, flags);
 719         if (port->port.tty)
 720                 clear_bit(TTY_IO_ERROR, &port->port.tty->flags);
 721         mutex_init(&port->port_write_mutex);
 722         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 723         spin_unlock_irqrestore(&port->driver_lock, flags);
 724         gs_set_termios(port->port.tty, NULL);
 725         spin_lock_irqsave (&port->driver_lock, flags);
 726         port->port.flags |= ASYNC_INITIALIZED;
 727         port->port.flags &= ~GS_TX_INTEN;
 728
 729         spin_unlock_irqrestore(&port->driver_lock, flags);
 730         func_exit ();
 731         return 0;
 732 }
 733
 734
 735 int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
 736 {
 737         struct serial_struct sio;
 738
 739         if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
 740                 return(-EFAULT);
 741
 742         if (!capable(CAP_SYS_ADMIN)) {
 743                 if ((sio.baud_base != port->baud_base) ||
 744                     (sio.close_delay != port->close_delay) ||
 745                     ((sio.flags & ~ASYNC_USR_MASK) !=
 746                      (port->port.flags & ~ASYNC_USR_MASK)))
 747                         return(-EPERM);
 748         }
 749
 750         port->port.flags = (port->port.flags & ~ASYNC_USR_MASK) |
 751                 (sio.flags & ASYNC_USR_MASK);
 752
 753         port->baud_base = sio.baud_base;
 754         port->close_delay = sio.close_delay;
 755         port->closing_wait = sio.closing_wait;
 756         port->custom_divisor = sio.custom_divisor;
 757
 758         gs_set_termios (port->port.tty, NULL);
 759
 760         return 0;
 761 }
 762
 763
 764 /*****************************************************************************/
 765
 766 /*
 767  *      Generate the serial struct info.
 768  */
 769
 770 int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
 771 {
 772         struct serial_struct    sio;
 773
 774         memset(&sio, 0, sizeof(struct serial_struct));
 775         sio.flags = port->port.flags;
 776         sio.baud_base = port->baud_base;
 777         sio.close_delay = port->close_delay;
 778         sio.closing_wait = port->closing_wait;
 779         sio.custom_divisor = port->custom_divisor;
 780         sio.hub6 = 0;
 781
 782         /* If you want you can override these. */
 783         sio.type = PORT_UNKNOWN;
 784         sio.xmit_fifo_size = -1;
 785         sio.line = -1;
 786         sio.port = -1;
 787         sio.irq = -1;
 788
 789         if (port->rd->getserial)
 790                 port->rd->getserial (port, &sio);
 791
 792         if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
 793                 return -EFAULT;
 794         return 0;
 795
 796 }
 797
 798
 799 void gs_got_break(struct gs_port *port)
 800 {
 801         func_enter ();
 802
 803         tty_insert_flip_char(port->port.tty, 0, TTY_BREAK);
 804         tty_schedule_flip(port->port.tty);
 805         if (port->port.flags & ASYNC_SAK) {
 806                 do_SAK (port->port.tty);
 807         }
 808
 809         func_exit ();
 810 }
 811
 812
 813 EXPORT_SYMBOL(gs_put_char);
 814 EXPORT_SYMBOL(gs_write);
 815 EXPORT_SYMBOL(gs_write_room);
 816 EXPORT_SYMBOL(gs_chars_in_buffer);
 817 EXPORT_SYMBOL(gs_flush_buffer);
 818 EXPORT_SYMBOL(gs_flush_chars);
 819 EXPORT_SYMBOL(gs_stop);
 820 EXPORT_SYMBOL(gs_start);
 821 EXPORT_SYMBOL(gs_hangup);
 822 EXPORT_SYMBOL(gs_block_til_ready);
 823 EXPORT_SYMBOL(gs_close);
 824 EXPORT_SYMBOL(gs_set_termios);
 825 EXPORT_SYMBOL(gs_init_port);
 826 EXPORT_SYMBOL(gs_setserial);
 827 EXPORT_SYMBOL(gs_getserial);
 828 EXPORT_SYMBOL(gs_got_break);
 829
 830 MODULE_LICENSE("GPL");