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         if (!tty) return 0;
  58
  59         port = tty->driver_data;
  60
  61         if (!port) return 0;
  62
  63         if (! (port->flags & ASYNC_INITIALIZED)) return 0;
  64
  65         /* Take a lock on the serial tranmit buffer! */
  66         mutex_lock(& port->port_write_mutex);
  67
  68         if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
  69                 /* Sorry, buffer is full, drop character. Update statistics???? -- REW */
  70                 mutex_unlock(&port->port_write_mutex);
  71                 return 0;
  72         }
  73
  74         port->xmit_buf[port->xmit_head++] = ch;
  75         port->xmit_head &= SERIAL_XMIT_SIZE - 1;
  76         port->xmit_cnt++;  /* Characters in buffer */
  77
  78         mutex_unlock(&port->port_write_mutex);
  79         func_exit ();
  80         return 1;
  81 }
  82
  83
  84 /*
  85 > Problems to take into account are:
  86 >       -1- Interrupts that empty part of the buffer.
  87 >       -2- page faults on the access to userspace.
  88 >       -3- Other processes that are also trying to do a "write".
  89 */
  90
  91 int gs_write(struct tty_struct * tty,
  92                     const unsigned char *buf, int count)
  93 {
  94         struct gs_port *port;
  95         int c, total = 0;
  96         int t;
  97
  98         func_enter ();
  99
 100         if (!tty) return 0;
 101
 102         port = tty->driver_data;
 103
 104         if (!port) return 0;
 105
 106         if (! (port->flags & ASYNC_INITIALIZED))
 107                 return 0;
 108
 109         /* get exclusive "write" access to this port (problem 3) */
 110         /* This is not a spinlock because we can have a disk access (page
 111                  fault) in copy_from_user */
 112         mutex_lock(& port->port_write_mutex);
 113
 114         while (1) {
 115
 116                 c = count;
 117
 118                 /* This is safe because we "OWN" the "head". Noone else can
 119                    change the "head": we own the port_write_mutex. */
 120                 /* Don't overrun the end of the buffer */
 121                 t = SERIAL_XMIT_SIZE - port->xmit_head;
 122                 if (t < c) c = t;
 123
 124                 /* This is safe because the xmit_cnt can only decrease. This
 125                    would increase "t", so we might copy too little chars. */
 126                 /* Don't copy past the "head" of the buffer */
 127                 t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
 128                 if (t < c) c = t;
 129
 130                 /* Can't copy more? break out! */
 131                 if (c <= 0) break;
 132
 133                 memcpy (port->xmit_buf + port->xmit_head, buf, c);
 134
 135                 port -> xmit_cnt += c;
 136                 port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
 137                 buf += c;
 138                 count -= c;
 139                 total += c;
 140         }
 141         mutex_unlock(& port->port_write_mutex);
 142
 143         gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n",
 144                     (port->flags & GS_TX_INTEN)?"enabled": "disabled");
 145
 146         if (port->xmit_cnt &&
 147             !tty->stopped &&
 148             !tty->hw_stopped &&
 149             !(port->flags & GS_TX_INTEN)) {
 150                 port->flags |= GS_TX_INTEN;
 151                 port->rd->enable_tx_interrupts (port);
 152         }
 153         func_exit ();
 154         return total;
 155 }
 156
 157
 158
 159 int gs_write_room(struct tty_struct * tty)
 160 {
 161         struct gs_port *port = tty->driver_data;
 162         int ret;
 163
 164         func_enter ();
 165         ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
 166         if (ret < 0)
 167                 ret = 0;
 168         func_exit ();
 169         return ret;
 170 }
 171
 172
 173 int gs_chars_in_buffer(struct tty_struct *tty)
 174 {
 175         struct gs_port *port = tty->driver_data;
 176         func_enter ();
 177
 178         func_exit ();
 179         return port->xmit_cnt;
 180 }
 181
 182
 183 static int gs_real_chars_in_buffer(struct tty_struct *tty)
 184 {
 185         struct gs_port *port;
 186         func_enter ();
 187
 188         if (!tty) return 0;
 189         port = tty->driver_data;
 190
 191         if (!port->rd) return 0;
 192         if (!port->rd->chars_in_buffer) return 0;
 193
 194         func_exit ();
 195         return port->xmit_cnt + port->rd->chars_in_buffer (port);
 196 }
 197
 198
 199 static int gs_wait_tx_flushed (void * ptr, unsigned long timeout)
 200 {
 201         struct gs_port *port = ptr;
 202         unsigned long end_jiffies;
 203         int jiffies_to_transmit, charsleft = 0, rv = 0;
 204         int rcib;
 205
 206         func_enter();
 207
 208         gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
 209         if (port) {
 210                 gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n",
 211                 port->xmit_cnt, port->xmit_buf, port->tty);
 212         }
 213
 214         if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
 215                 gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
 216                 func_exit();
 217                 return -EINVAL;  /* This is an error which we don't know how to handle. */
 218         }
 219
 220         rcib = gs_real_chars_in_buffer(port->tty);
 221
 222         if(rcib <= 0) {
 223                 gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
 224                 func_exit();
 225                 return rv;
 226         }
 227         /* stop trying: now + twice the time it would normally take +  seconds */
 228         if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
 229         end_jiffies  = jiffies;
 230         if (timeout !=  MAX_SCHEDULE_TIMEOUT)
 231                 end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
 232         end_jiffies += timeout;
 233
 234         gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n",
 235                     jiffies, end_jiffies, end_jiffies-jiffies);
 236
 237         /* the expression is actually jiffies < end_jiffies, but that won't
 238            work around the wraparound. Tricky eh? */
 239         while ((charsleft = gs_real_chars_in_buffer (port->tty)) &&
 240                 time_after (end_jiffies, jiffies)) {
 241                 /* Units check:
 242                    chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
 243                    check! */
 244
 245                 charsleft += 16; /* Allow 16 chars more to be transmitted ... */
 246                 jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
 247                 /*                                ^^^ Round up.... */
 248                 if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;
 249
 250                 gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
 251                             "(%d chars).\n", jiffies_to_transmit, charsleft);
 252
 253                 msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
 254                 if (signal_pending (current)) {
 255                         gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: ");
 256                         rv = -EINTR;
 257                         break;
 258                 }
 259         }
 260
 261         gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft);
 262         set_current_state (TASK_RUNNING);
 263
 264         func_exit();
 265         return rv;
 266 }
 267
 268
 269
 270 void gs_flush_buffer(struct tty_struct *tty)
 271 {
 272         struct gs_port *port;
 273         unsigned long flags;
 274
 275         func_enter ();
 276
 277         if (!tty) return;
 278
 279         port = tty->driver_data;
 280
 281         if (!port) return;
 282
 283         /* XXX Would the write semaphore do? */
 284         spin_lock_irqsave (&port->driver_lock, flags);
 285         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 286         spin_unlock_irqrestore (&port->driver_lock, flags);
 287
 288         tty_wakeup(tty);
 289         func_exit ();
 290 }
 291
 292
 293 void gs_flush_chars(struct tty_struct * tty)
 294 {
 295         struct gs_port *port;
 296
 297         func_enter ();
 298
 299         if (!tty) return;
 300
 301         port = tty->driver_data;
 302
 303         if (!port) return;
 304
 305         if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
 306             !port->xmit_buf) {
 307                 func_exit ();
 308                 return;
 309         }
 310
 311         /* Beats me -- REW */
 312         port->flags |= GS_TX_INTEN;
 313         port->rd->enable_tx_interrupts (port);
 314         func_exit ();
 315 }
 316
 317
 318 void gs_stop(struct tty_struct * tty)
 319 {
 320         struct gs_port *port;
 321
 322         func_enter ();
 323
 324         if (!tty) return;
 325
 326         port = tty->driver_data;
 327
 328         if (!port) return;
 329
 330         if (port->xmit_cnt &&
 331             port->xmit_buf &&
 332             (port->flags & GS_TX_INTEN) ) {
 333                 port->flags &= ~GS_TX_INTEN;
 334                 port->rd->disable_tx_interrupts (port);
 335         }
 336         func_exit ();
 337 }
 338
 339
 340 void gs_start(struct tty_struct * tty)
 341 {
 342         struct gs_port *port;
 343
 344         if (!tty) return;
 345
 346         port = tty->driver_data;
 347
 348         if (!port) return;
 349
 350         if (port->xmit_cnt &&
 351             port->xmit_buf &&
 352             !(port->flags & GS_TX_INTEN) ) {
 353                 port->flags |= GS_TX_INTEN;
 354                 port->rd->enable_tx_interrupts (port);
 355         }
 356         func_exit ();
 357 }
 358
 359
 360 static void gs_shutdown_port (struct gs_port *port)
 361 {
 362         unsigned long flags;
 363
 364         func_enter();
 365
 366         if (!port) return;
 367
 368         if (!(port->flags & ASYNC_INITIALIZED))
 369                 return;
 370
 371         spin_lock_irqsave(&port->driver_lock, flags);
 372
 373         if (port->xmit_buf) {
 374                 free_page((unsigned long) port->xmit_buf);
 375                 port->xmit_buf = NULL;
 376         }
 377
 378         if (port->tty)
 379                 set_bit(TTY_IO_ERROR, &port->tty->flags);
 380
 381         port->rd->shutdown_port (port);
 382
 383         port->flags &= ~ASYNC_INITIALIZED;
 384         spin_unlock_irqrestore(&port->driver_lock, flags);
 385
 386         func_exit();
 387 }
 388
 389
 390 void gs_hangup(struct tty_struct *tty)
 391 {
 392         struct gs_port   *port;
 393
 394         func_enter ();
 395
 396         if (!tty) return;
 397
 398         port = tty->driver_data;
 399         tty = port->tty;
 400         if (!tty)
 401                 return;
 402
 403         gs_shutdown_port (port);
 404         port->flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
 405         port->tty = NULL;
 406         port->count = 0;
 407
 408         wake_up_interruptible(&port->open_wait);
 409         func_exit ();
 410 }
 411
 412
 413 int gs_block_til_ready(void *port_, struct file * filp)
 414 {
 415         struct gs_port *port = port_;
 416         DECLARE_WAITQUEUE(wait, current);
 417         int    retval;
 418         int    do_clocal = 0;
 419         int    CD;
 420         struct tty_struct *tty;
 421         unsigned long flags;
 422
 423         func_enter ();
 424
 425         if (!port) return 0;
 426
 427         tty = port->tty;
 428
 429         if (!tty) return 0;
 430
 431         gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
 432         /*
 433          * If the device is in the middle of being closed, then block
 434          * until it's done, and then try again.
 435          */
 436         if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
 437                 interruptible_sleep_on(&port->close_wait);
 438                 if (port->flags & ASYNC_HUP_NOTIFY)
 439                         return -EAGAIN;
 440                 else
 441                         return -ERESTARTSYS;
 442         }
 443
 444         gs_dprintk (GS_DEBUG_BTR, "after hung up\n");
 445
 446         /*
 447          * If non-blocking mode is set, or the port is not enabled,
 448          * then make the check up front and then exit.
 449          */
 450         if ((filp->f_flags & O_NONBLOCK) ||
 451             (tty->flags & (1 << TTY_IO_ERROR))) {
 452                 port->flags |= ASYNC_NORMAL_ACTIVE;
 453                 return 0;
 454         }
 455
 456         gs_dprintk (GS_DEBUG_BTR, "after nonblock\n");
 457
 458         if (C_CLOCAL(tty))
 459                 do_clocal = 1;
 460
 461         /*
 462          * Block waiting for the carrier detect and the line to become
 463          * free (i.e., not in use by the callout).  While we are in
 464          * this loop, port->count is dropped by one, so that
 465          * rs_close() knows when to free things.  We restore it upon
 466          * exit, either normal or abnormal.
 467          */
 468         retval = 0;
 469
 470         add_wait_queue(&port->open_wait, &wait);
 471
 472         gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
 473         spin_lock_irqsave(&port->driver_lock, flags);
 474         if (!tty_hung_up_p(filp)) {
 475                 port->count--;
 476         }
 477         spin_unlock_irqrestore(&port->driver_lock, flags);
 478         port->blocked_open++;
 479         while (1) {
 480                 CD = port->rd->get_CD (port);
 481                 gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
 482                 set_current_state (TASK_INTERRUPTIBLE);
 483                 if (tty_hung_up_p(filp) ||
 484                     !(port->flags & ASYNC_INITIALIZED)) {
 485                         if (port->flags & ASYNC_HUP_NOTIFY)
 486                                 retval = -EAGAIN;
 487                         else
 488                                 retval = -ERESTARTSYS;
 489                         break;
 490                 }
 491                 if (!(port->flags & ASYNC_CLOSING) &&
 492                     (do_clocal || CD))
 493                         break;
 494                 gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
 495                 (int)signal_pending (current), *(long*)(&current->blocked));
 496                 if (signal_pending(current)) {
 497                         retval = -ERESTARTSYS;
 498                         break;
 499                 }
 500                 schedule();
 501         }
 502         gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
 503                     port->blocked_open);
 504         set_current_state (TASK_RUNNING);
 505         remove_wait_queue(&port->open_wait, &wait);
 506         if (!tty_hung_up_p(filp)) {
 507                 port->count++;
 508         }
 509         port->blocked_open--;
 510         if (retval)
 511                 return retval;
 512
 513         port->flags |= ASYNC_NORMAL_ACTIVE;
 514         func_exit ();
 515         return 0;
 516 }
 517
 518
 519 void gs_close(struct tty_struct * tty, struct file * filp)
 520 {
 521         unsigned long flags;
 522         struct gs_port *port;
 523
 524         func_enter ();
 525
 526         if (!tty) return;
 527
 528         port = (struct gs_port *) tty->driver_data;
 529
 530         if (!port) return;
 531
 532         if (!port->tty) {
 533                 /* This seems to happen when this is called from vhangup. */
 534                 gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->tty is NULL\n");
 535                 port->tty = tty;
 536         }
 537
 538         spin_lock_irqsave(&port->driver_lock, flags);
 539
 540         if (tty_hung_up_p(filp)) {
 541                 spin_unlock_irqrestore(&port->driver_lock, flags);
 542                 if (port->rd->hungup)
 543                         port->rd->hungup (port);
 544                 func_exit ();
 545                 return;
 546         }
 547
 548         if ((tty->count == 1) && (port->count != 1)) {
 549                 printk(KERN_ERR "gs: gs_close port %p: bad port count;"
 550                        " tty->count is 1, port count is %d\n", port, port->count);
 551                 port->count = 1;
 552         }
 553         if (--port->count < 0) {
 554                 printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->count);
 555                 port->count = 0;
 556         }
 557
 558         if (port->count) {
 559                 gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->count);
 560                 spin_unlock_irqrestore(&port->driver_lock, flags);
 561                 func_exit ();
 562                 return;
 563         }
 564         port->flags |= ASYNC_CLOSING;
 565
 566         /*
 567          * Now we wait for the transmit buffer to clear; and we notify
 568          * the line discipline to only process XON/XOFF characters.
 569          */
 570         tty->closing = 1;
 571         /* if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 572            tty_wait_until_sent(tty, port->closing_wait); */
 573
 574         /*
 575          * At this point we stop accepting input.  To do this, we
 576          * disable the receive line status interrupts, and tell the
 577          * interrupt driver to stop checking the data ready bit in the
 578          * line status register.
 579          */
 580
 581         port->rd->disable_rx_interrupts (port);
 582         spin_unlock_irqrestore(&port->driver_lock, flags);
 583
 584         /* close has no way of returning "EINTR", so discard return value */
 585         if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 586                 gs_wait_tx_flushed (port, port->closing_wait);
 587
 588         port->flags &= ~GS_ACTIVE;
 589
 590         gs_flush_buffer(tty);
 591
 592         tty_ldisc_flush(tty);
 593         tty->closing = 0;
 594
 595         port->event = 0;
 596         port->rd->close (port);
 597         port->rd->shutdown_port (port);
 598         port->tty = NULL;
 599
 600         if (port->blocked_open) {
 601                 if (port->close_delay) {
 602                         spin_unlock_irqrestore(&port->driver_lock, flags);
 603                         msleep_interruptible(jiffies_to_msecs(port->close_delay));
 604                         spin_lock_irqsave(&port->driver_lock, flags);
 605                 }
 606                 wake_up_interruptible(&port->open_wait);
 607         }
 608         port->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
 609         wake_up_interruptible(&port->close_wait);
 610
 611         func_exit ();
 612 }
 613
 614
 615 void gs_set_termios (struct tty_struct * tty,
 616                      struct ktermios * old_termios)
 617 {
 618         struct gs_port *port;
 619         int baudrate, tmp, rv;
 620         struct ktermios *tiosp;
 621
 622         func_enter();
 623
 624         if (!tty) return;
 625
 626         port = tty->driver_data;
 627
 628         if (!port) return;
 629         if (!port->tty) {
 630                 /* This seems to happen when this is called after gs_close. */
 631                 gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->tty is NULL\n");
 632                 port->tty = tty;
 633         }
 634
 635
 636         tiosp = tty->termios;
 637
 638         if (gs_debug & GS_DEBUG_TERMIOS) {
 639                 gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
 640         }
 641
 642         if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
 643                 if(tiosp->c_iflag != old_termios->c_iflag)  printk("c_iflag changed\n");
 644                 if(tiosp->c_oflag != old_termios->c_oflag)  printk("c_oflag changed\n");
 645                 if(tiosp->c_cflag != old_termios->c_cflag)  printk("c_cflag changed\n");
 646                 if(tiosp->c_lflag != old_termios->c_lflag)  printk("c_lflag changed\n");
 647                 if(tiosp->c_line  != old_termios->c_line)   printk("c_line changed\n");
 648                 if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
 649         }
 650
 651         baudrate = tty_get_baud_rate(tty);
 652
 653         if ((tiosp->c_cflag & CBAUD) == B38400) {
 654                 if (     (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
 655                         baudrate = 57600;
 656                 else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
 657                         baudrate = 115200;
 658                 else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
 659                         baudrate = 230400;
 660                 else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
 661                         baudrate = 460800;
 662                 else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
 663                         baudrate = (port->baud_base / port->custom_divisor);
 664         }
 665
 666         /* I recommend using THIS instead of the mess in termios (and
 667            duplicating the above code). Next we should create a clean
 668            interface towards this variable. If your card supports arbitrary
 669            baud rates, (e.g. CD1400 or 16550 based cards) then everything
 670            will be very easy..... */
 671         port->baud = baudrate;
 672
 673         /* Two timer ticks seems enough to wakeup something like SLIP driver */
 674         /* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
 675         tmp = (baudrate / 10 / HZ) * 2;
 676
 677         if (tmp <                 0) tmp = 0;
 678         if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;
 679
 680         port->wakeup_chars = tmp;
 681
 682         /* We should really wait for the characters to be all sent before
 683            changing the settings. -- CAL */
 684         rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
 685         if (rv < 0) return /* rv */;
 686
 687         rv = port->rd->set_real_termios(port);
 688         if (rv < 0) return /* rv */;
 689
 690         if ((!old_termios ||
 691              (old_termios->c_cflag & CRTSCTS)) &&
 692             !(      tiosp->c_cflag & CRTSCTS)) {
 693                 tty->stopped = 0;
 694                 gs_start(tty);
 695         }
 696
 697 #ifdef tytso_patch_94Nov25_1726
 698         /* This "makes sense", Why is it commented out? */
 699
 700         if (!(old_termios->c_cflag & CLOCAL) &&
 701             (tty->termios->c_cflag & CLOCAL))
 702                 wake_up_interruptible(&port->gs.open_wait);
 703 #endif
 704
 705         func_exit();
 706         return /* 0 */;
 707 }
 708
 709
 710
 711 /* Must be called with interrupts enabled */
 712 int gs_init_port(struct gs_port *port)
 713 {
 714         unsigned long flags;
 715
 716         func_enter ();
 717
 718         if (port->flags & ASYNC_INITIALIZED) {
 719                 func_exit ();
 720                 return 0;
 721         }
 722         if (!port->xmit_buf) {
 723                 /* We may sleep in get_zeroed_page() */
 724                 unsigned long tmp;
 725
 726                 tmp = get_zeroed_page(GFP_KERNEL);
 727                 spin_lock_irqsave (&port->driver_lock, flags);
 728                 if (port->xmit_buf)
 729                         free_page (tmp);
 730                 else
 731                         port->xmit_buf = (unsigned char *) tmp;
 732                 spin_unlock_irqrestore(&port->driver_lock, flags);
 733                 if (!port->xmit_buf) {
 734                         func_exit ();
 735                         return -ENOMEM;
 736                 }
 737         }
 738
 739         spin_lock_irqsave (&port->driver_lock, flags);
 740         if (port->tty)
 741                 clear_bit(TTY_IO_ERROR, &port->tty->flags);
 742         mutex_init(&port->port_write_mutex);
 743         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 744         spin_unlock_irqrestore(&port->driver_lock, flags);
 745         gs_set_termios(port->tty, NULL);
 746         spin_lock_irqsave (&port->driver_lock, flags);
 747         port->flags |= ASYNC_INITIALIZED;
 748         port->flags &= ~GS_TX_INTEN;
 749
 750         spin_unlock_irqrestore(&port->driver_lock, flags);
 751         func_exit ();
 752         return 0;
 753 }
 754
 755
 756 int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
 757 {
 758         struct serial_struct sio;
 759
 760         if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
 761                 return(-EFAULT);
 762
 763         if (!capable(CAP_SYS_ADMIN)) {
 764                 if ((sio.baud_base != port->baud_base) ||
 765                     (sio.close_delay != port->close_delay) ||
 766                     ((sio.flags & ~ASYNC_USR_MASK) !=
 767                      (port->flags & ~ASYNC_USR_MASK)))
 768                         return(-EPERM);
 769         }
 770
 771         port->flags = (port->flags & ~ASYNC_USR_MASK) |
 772                 (sio.flags & ASYNC_USR_MASK);
 773
 774         port->baud_base = sio.baud_base;
 775         port->close_delay = sio.close_delay;
 776         port->closing_wait = sio.closing_wait;
 777         port->custom_divisor = sio.custom_divisor;
 778
 779         gs_set_termios (port->tty, NULL);
 780
 781         return 0;
 782 }
 783
 784
 785 /*****************************************************************************/
 786
 787 /*
 788  *      Generate the serial struct info.
 789  */
 790
 791 int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
 792 {
 793         struct serial_struct    sio;
 794
 795         memset(&sio, 0, sizeof(struct serial_struct));
 796         sio.flags = port->flags;
 797         sio.baud_base = port->baud_base;
 798         sio.close_delay = port->close_delay;
 799         sio.closing_wait = port->closing_wait;
 800         sio.custom_divisor = port->custom_divisor;
 801         sio.hub6 = 0;
 802
 803         /* If you want you can override these. */
 804         sio.type = PORT_UNKNOWN;
 805         sio.xmit_fifo_size = -1;
 806         sio.line = -1;
 807         sio.port = -1;
 808         sio.irq = -1;
 809
 810         if (port->rd->getserial)
 811                 port->rd->getserial (port, &sio);
 812
 813         if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
 814                 return -EFAULT;
 815         return 0;
 816
 817 }
 818
 819
 820 void gs_got_break(struct gs_port *port)
 821 {
 822         func_enter ();
 823
 824         tty_insert_flip_char(port->tty, 0, TTY_BREAK);
 825         tty_schedule_flip(port->tty);
 826         if (port->flags & ASYNC_SAK) {
 827                 do_SAK (port->tty);
 828         }
 829
 830         func_exit ();
 831 }
 832
 833
 834 EXPORT_SYMBOL(gs_put_char);
 835 EXPORT_SYMBOL(gs_write);
 836 EXPORT_SYMBOL(gs_write_room);
 837 EXPORT_SYMBOL(gs_chars_in_buffer);
 838 EXPORT_SYMBOL(gs_flush_buffer);
 839 EXPORT_SYMBOL(gs_flush_chars);
 840 EXPORT_SYMBOL(gs_stop);
 841 EXPORT_SYMBOL(gs_start);
 842 EXPORT_SYMBOL(gs_hangup);
 843 EXPORT_SYMBOL(gs_block_til_ready);
 844 EXPORT_SYMBOL(gs_close);
 845 EXPORT_SYMBOL(gs_set_termios);
 846 EXPORT_SYMBOL(gs_init_port);
 847 EXPORT_SYMBOL(gs_setserial);
 848 EXPORT_SYMBOL(gs_getserial);
 849 EXPORT_SYMBOL(gs_got_break);
 850
 851 MODULE_LICENSE("GPL");