drivers/staging/generic_serial/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/sched.h>
  26 #include <linux/serial.h>
  27 #include <linux/mm.h>
  28 #include <linux/generic_serial.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/tty_flip.h>
  31 #include <linux/delay.h>
  32 #include <linux/gfp.h>
  33 #include <asm/uaccess.h>
  34
  35 #define DEBUG
  36
  37 static int gs_debug;
  38
  39 #ifdef DEBUG
  40 #define gs_dprintk(f, str...) if (gs_debug & f) printk (str)
  41 #else
  42 #define gs_dprintk(f, str...) /* nothing */
  43 #endif
  44
  45 #define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __func__)
  46 #define func_exit()  gs_dprintk (GS_DEBUG_FLOW, "gs: exit  %s\n", __func__)
  47
  48 #define RS_EVENT_WRITE_WAKEUP   1
  49
  50 module_param(gs_debug, int, 0644);
  51
  52
  53 int gs_put_char(struct tty_struct * tty, unsigned char ch)
  54 {
  55         struct gs_port *port;
  56
  57         func_enter ();
  58
  59         port = tty->driver_data;
  60
  61         if (!port) return 0;
  62
  63         if (! (port->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         port = tty->driver_data;
 101
 102         if (!port) return 0;
 103
 104         if (! (port->port.flags & ASYNC_INITIALIZED))
 105                 return 0;
 106
 107         /* get exclusive "write" access to this port (problem 3) */
 108         /* This is not a spinlock because we can have a disk access (page
 109                  fault) in copy_from_user */
 110         mutex_lock(& port->port_write_mutex);
 111
 112         while (1) {
 113
 114                 c = count;
 115
 116                 /* This is safe because we "OWN" the "head". No one else can
 117                    change the "head": we own the port_write_mutex. */
 118                 /* Don't overrun the end of the buffer */
 119                 t = SERIAL_XMIT_SIZE - port->xmit_head;
 120                 if (t < c) c = t;
 121
 122                 /* This is safe because the xmit_cnt can only decrease. This
 123                    would increase "t", so we might copy too little chars. */
 124                 /* Don't copy past the "head" of the buffer */
 125                 t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
 126                 if (t < c) c = t;
 127
 128                 /* Can't copy more? break out! */
 129                 if (c <= 0) break;
 130
 131                 memcpy (port->xmit_buf + port->xmit_head, buf, c);
 132
 133                 port -> xmit_cnt += c;
 134                 port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
 135                 buf += c;
 136                 count -= c;
 137                 total += c;
 138         }
 139         mutex_unlock(& port->port_write_mutex);
 140
 141         gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n",
 142                     (port->port.flags & GS_TX_INTEN)?"enabled": "disabled");
 143
 144         if (port->xmit_cnt &&
 145             !tty->stopped &&
 146             !tty->hw_stopped &&
 147             !(port->port.flags & GS_TX_INTEN)) {
 148                 port->port.flags |= GS_TX_INTEN;
 149                 port->rd->enable_tx_interrupts (port);
 150         }
 151         func_exit ();
 152         return total;
 153 }
 154
 155
 156
 157 int gs_write_room(struct tty_struct * tty)
 158 {
 159         struct gs_port *port = tty->driver_data;
 160         int ret;
 161
 162         func_enter ();
 163         ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
 164         if (ret < 0)
 165                 ret = 0;
 166         func_exit ();
 167         return ret;
 168 }
 169
 170
 171 int gs_chars_in_buffer(struct tty_struct *tty)
 172 {
 173         struct gs_port *port = tty->driver_data;
 174         func_enter ();
 175
 176         func_exit ();
 177         return port->xmit_cnt;
 178 }
 179
 180
 181 static int gs_real_chars_in_buffer(struct tty_struct *tty)
 182 {
 183         struct gs_port *port;
 184         func_enter ();
 185
 186         port = tty->driver_data;
 187
 188         if (!port->rd) return 0;
 189         if (!port->rd->chars_in_buffer) return 0;
 190
 191         func_exit ();
 192         return port->xmit_cnt + port->rd->chars_in_buffer (port);
 193 }
 194
 195
 196 static int gs_wait_tx_flushed (void * ptr, unsigned long timeout)
 197 {
 198         struct gs_port *port = ptr;
 199         unsigned long end_jiffies;
 200         int jiffies_to_transmit, charsleft = 0, rv = 0;
 201         int rcib;
 202
 203         func_enter();
 204
 205         gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
 206         if (port) {
 207                 gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n",
 208                 port->xmit_cnt, port->xmit_buf, port->port.tty);
 209         }
 210
 211         if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
 212                 gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
 213                 func_exit();
 214                 return -EINVAL;  /* This is an error which we don't know how to handle. */
 215         }
 216
 217         rcib = gs_real_chars_in_buffer(port->port.tty);
 218
 219         if(rcib <= 0) {
 220                 gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
 221                 func_exit();
 222                 return rv;
 223         }
 224         /* stop trying: now + twice the time it would normally take +  seconds */
 225         if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
 226         end_jiffies  = jiffies;
 227         if (timeout !=  MAX_SCHEDULE_TIMEOUT)
 228                 end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
 229         end_jiffies += timeout;
 230
 231         gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n",
 232                     jiffies, end_jiffies, end_jiffies-jiffies);
 233
 234         /* the expression is actually jiffies < end_jiffies, but that won't
 235            work around the wraparound. Tricky eh? */
 236         while ((charsleft = gs_real_chars_in_buffer (port->port.tty)) &&
 237                 time_after (end_jiffies, jiffies)) {
 238                 /* Units check:
 239                    chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
 240                    check! */
 241
 242                 charsleft += 16; /* Allow 16 chars more to be transmitted ... */
 243                 jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
 244                 /*                                ^^^ Round up.... */
 245                 if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;
 246
 247                 gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
 248                             "(%d chars).\n", jiffies_to_transmit, charsleft);
 249
 250                 msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
 251                 if (signal_pending (current)) {
 252                         gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: ");
 253                         rv = -EINTR;
 254                         break;
 255                 }
 256         }
 257
 258         gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft);
 259         set_current_state (TASK_RUNNING);
 260
 261         func_exit();
 262         return rv;
 263 }
 264
 265
 266
 267 void gs_flush_buffer(struct tty_struct *tty)
 268 {
 269         struct gs_port *port;
 270         unsigned long flags;
 271
 272         func_enter ();
 273
 274         port = tty->driver_data;
 275
 276         if (!port) return;
 277
 278         /* XXX Would the write semaphore do? */
 279         spin_lock_irqsave (&port->driver_lock, flags);
 280         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 281         spin_unlock_irqrestore (&port->driver_lock, flags);
 282
 283         tty_wakeup(tty);
 284         func_exit ();
 285 }
 286
 287
 288 void gs_flush_chars(struct tty_struct * tty)
 289 {
 290         struct gs_port *port;
 291
 292         func_enter ();
 293
 294         port = tty->driver_data;
 295
 296         if (!port) return;
 297
 298         if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
 299             !port->xmit_buf) {
 300                 func_exit ();
 301                 return;
 302         }
 303
 304         /* Beats me -- REW */
 305         port->port.flags |= GS_TX_INTEN;
 306         port->rd->enable_tx_interrupts (port);
 307         func_exit ();
 308 }
 309
 310
 311 void gs_stop(struct tty_struct * tty)
 312 {
 313         struct gs_port *port;
 314
 315         func_enter ();
 316
 317         port = tty->driver_data;
 318
 319         if (!port) return;
 320
 321         if (port->xmit_cnt &&
 322             port->xmit_buf &&
 323             (port->port.flags & GS_TX_INTEN) ) {
 324                 port->port.flags &= ~GS_TX_INTEN;
 325                 port->rd->disable_tx_interrupts (port);
 326         }
 327         func_exit ();
 328 }
 329
 330
 331 void gs_start(struct tty_struct * tty)
 332 {
 333         struct gs_port *port;
 334
 335         port = tty->driver_data;
 336
 337         if (!port) return;
 338
 339         if (port->xmit_cnt &&
 340             port->xmit_buf &&
 341             !(port->port.flags & GS_TX_INTEN) ) {
 342                 port->port.flags |= GS_TX_INTEN;
 343                 port->rd->enable_tx_interrupts (port);
 344         }
 345         func_exit ();
 346 }
 347
 348
 349 static void gs_shutdown_port (struct gs_port *port)
 350 {
 351         unsigned long flags;
 352
 353         func_enter();
 354
 355         if (!port) return;
 356
 357         if (!(port->port.flags & ASYNC_INITIALIZED))
 358                 return;
 359
 360         spin_lock_irqsave(&port->driver_lock, flags);
 361
 362         if (port->xmit_buf) {
 363                 free_page((unsigned long) port->xmit_buf);
 364                 port->xmit_buf = NULL;
 365         }
 366
 367         if (port->port.tty)
 368                 set_bit(TTY_IO_ERROR, &port->port.tty->flags);
 369
 370         port->rd->shutdown_port (port);
 371
 372         port->port.flags &= ~ASYNC_INITIALIZED;
 373         spin_unlock_irqrestore(&port->driver_lock, flags);
 374
 375         func_exit();
 376 }
 377
 378
 379 void gs_hangup(struct tty_struct *tty)
 380 {
 381         struct gs_port *port;
 382         unsigned long flags;
 383
 384         func_enter ();
 385
 386         port = tty->driver_data;
 387         tty = port->port.tty;
 388         if (!tty)
 389                 return;
 390
 391         gs_shutdown_port (port);
 392         spin_lock_irqsave(&port->port.lock, flags);
 393         port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
 394         port->port.tty = NULL;
 395         port->port.count = 0;
 396         spin_unlock_irqrestore(&port->port.lock, flags);
 397
 398         wake_up_interruptible(&port->port.open_wait);
 399         func_exit ();
 400 }
 401
 402
 403 int gs_block_til_ready(void *port_, struct file * filp)
 404 {
 405         struct gs_port *gp = port_;
 406         struct tty_port *port = &gp->port;
 407         DECLARE_WAITQUEUE(wait, current);
 408         int    retval;
 409         int    do_clocal = 0;
 410         int    CD;
 411         struct tty_struct *tty;
 412         unsigned long flags;
 413
 414         func_enter ();
 415
 416         if (!port) return 0;
 417
 418         tty = port->tty;
 419
 420         gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
 421         /*
 422          * If the device is in the middle of being closed, then block
 423          * until it's done, and then try again.
 424          */
 425         if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
 426                 interruptible_sleep_on(&port->close_wait);
 427                 if (port->flags & ASYNC_HUP_NOTIFY)
 428                         return -EAGAIN;
 429                 else
 430                         return -ERESTARTSYS;
 431         }
 432
 433         gs_dprintk (GS_DEBUG_BTR, "after hung up\n");
 434
 435         /*
 436          * If non-blocking mode is set, or the port is not enabled,
 437          * then make the check up front and then exit.
 438          */
 439         if ((filp->f_flags & O_NONBLOCK) ||
 440             (tty->flags & (1 << TTY_IO_ERROR))) {
 441                 port->flags |= ASYNC_NORMAL_ACTIVE;
 442                 return 0;
 443         }
 444
 445         gs_dprintk (GS_DEBUG_BTR, "after nonblock\n");
 446
 447         if (C_CLOCAL(tty))
 448                 do_clocal = 1;
 449
 450         /*
 451          * Block waiting for the carrier detect and the line to become
 452          * free (i.e., not in use by the callout).  While we are in
 453          * this loop, port->count is dropped by one, so that
 454          * rs_close() knows when to free things.  We restore it upon
 455          * exit, either normal or abnormal.
 456          */
 457         retval = 0;
 458
 459         add_wait_queue(&port->open_wait, &wait);
 460
 461         gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
 462         spin_lock_irqsave(&port->lock, flags);
 463         if (!tty_hung_up_p(filp)) {
 464                 port->count--;
 465         }
 466         port->blocked_open++;
 467         spin_unlock_irqrestore(&port->lock, flags);
 468         while (1) {
 469                 CD = tty_port_carrier_raised(port);
 470                 gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
 471                 set_current_state (TASK_INTERRUPTIBLE);
 472                 if (tty_hung_up_p(filp) ||
 473                     !(port->flags & ASYNC_INITIALIZED)) {
 474                         if (port->flags & ASYNC_HUP_NOTIFY)
 475                                 retval = -EAGAIN;
 476                         else
 477                                 retval = -ERESTARTSYS;
 478                         break;
 479                 }
 480                 if (!(port->flags & ASYNC_CLOSING) &&
 481                     (do_clocal || CD))
 482                         break;
 483                 gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
 484                 (int)signal_pending (current), *(long*)(&current->blocked));
 485                 if (signal_pending(current)) {
 486                         retval = -ERESTARTSYS;
 487                         break;
 488                 }
 489                 schedule();
 490         }
 491         gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
 492                     port->blocked_open);
 493         set_current_state (TASK_RUNNING);
 494         remove_wait_queue(&port->open_wait, &wait);
 495
 496         spin_lock_irqsave(&port->lock, flags);
 497         if (!tty_hung_up_p(filp)) {
 498                 port->count++;
 499         }
 500         port->blocked_open--;
 501         if (retval == 0)
 502                 port->flags |= ASYNC_NORMAL_ACTIVE;
 503         spin_unlock_irqrestore(&port->lock, flags);
 504         func_exit ();
 505         return retval;
 506 }
 507
 508
 509 void gs_close(struct tty_struct * tty, struct file * filp)
 510 {
 511         unsigned long flags;
 512         struct gs_port *port;
 513
 514         func_enter ();
 515
 516         port = tty->driver_data;
 517
 518         if (!port) return;
 519
 520         if (!port->port.tty) {
 521                 /* This seems to happen when this is called from vhangup. */
 522                 gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->port.tty is NULL\n");
 523                 port->port.tty = tty;
 524         }
 525
 526         spin_lock_irqsave(&port->port.lock, flags);
 527
 528         if (tty_hung_up_p(filp)) {
 529                 spin_unlock_irqrestore(&port->port.lock, flags);
 530                 if (port->rd->hungup)
 531                         port->rd->hungup (port);
 532                 func_exit ();
 533                 return;
 534         }
 535
 536         if ((tty->count == 1) && (port->port.count != 1)) {
 537                 printk(KERN_ERR "gs: gs_close port %p: bad port count;"
 538                        " tty->count is 1, port count is %d\n", port, port->port.count);
 539                 port->port.count = 1;
 540         }
 541         if (--port->port.count < 0) {
 542                 printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->port.count);
 543                 port->port.count = 0;
 544         }
 545
 546         if (port->port.count) {
 547                 gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->port.count);
 548                 spin_unlock_irqrestore(&port->port.lock, flags);
 549                 func_exit ();
 550                 return;
 551         }
 552         port->port.flags |= ASYNC_CLOSING;
 553
 554         /*
 555          * Now we wait for the transmit buffer to clear; and we notify
 556          * the line discipline to only process XON/XOFF characters.
 557          */
 558         tty->closing = 1;
 559         /* if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 560            tty_wait_until_sent(tty, port->closing_wait); */
 561
 562         /*
 563          * At this point we stop accepting input.  To do this, we
 564          * disable the receive line status interrupts, and tell the
 565          * interrupt driver to stop checking the data ready bit in the
 566          * line status register.
 567          */
 568
 569         spin_lock(&port->driver_lock);
 570         port->rd->disable_rx_interrupts (port);
 571         spin_unlock(&port->driver_lock);
 572         spin_unlock_irqrestore(&port->port.lock, flags);
 573
 574         /* close has no way of returning "EINTR", so discard return value */
 575         if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 576                 gs_wait_tx_flushed (port, port->closing_wait);
 577
 578         port->port.flags &= ~GS_ACTIVE;
 579
 580         gs_flush_buffer(tty);
 581
 582         tty_ldisc_flush(tty);
 583         tty->closing = 0;
 584
 585         spin_lock_irqsave(&port->driver_lock, flags);
 586         port->event = 0;
 587         port->rd->close (port);
 588         port->rd->shutdown_port (port);
 589         spin_unlock_irqrestore(&port->driver_lock, flags);
 590
 591         spin_lock_irqsave(&port->port.lock, flags);
 592         port->port.tty = NULL;
 593
 594         if (port->port.blocked_open) {
 595                 if (port->close_delay) {
 596                         spin_unlock_irqrestore(&port->port.lock, flags);
 597                         msleep_interruptible(jiffies_to_msecs(port->close_delay));
 598                         spin_lock_irqsave(&port->port.lock, flags);
 599                 }
 600                 wake_up_interruptible(&port->port.open_wait);
 601         }
 602         port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
 603         spin_unlock_irqrestore(&port->port.lock, flags);
 604         wake_up_interruptible(&port->port.close_wait);
 605
 606         func_exit ();
 607 }
 608
 609
 610 void gs_set_termios (struct tty_struct * tty,
 611                      struct ktermios * old_termios)
 612 {
 613         struct gs_port *port;
 614         int baudrate, tmp, rv;
 615         struct ktermios *tiosp;
 616
 617         func_enter();
 618
 619         port = tty->driver_data;
 620
 621         if (!port) return;
 622         if (!port->port.tty) {
 623                 /* This seems to happen when this is called after gs_close. */
 624                 gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->port.tty is NULL\n");
 625                 port->port.tty = tty;
 626         }
 627
 628
 629         tiosp = tty->termios;
 630
 631         if (gs_debug & GS_DEBUG_TERMIOS) {
 632                 gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
 633         }
 634
 635         if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
 636                 if(tiosp->c_iflag != old_termios->c_iflag)  printk("c_iflag changed\n");
 637                 if(tiosp->c_oflag != old_termios->c_oflag)  printk("c_oflag changed\n");
 638                 if(tiosp->c_cflag != old_termios->c_cflag)  printk("c_cflag changed\n");
 639                 if(tiosp->c_lflag != old_termios->c_lflag)  printk("c_lflag changed\n");
 640                 if(tiosp->c_line  != old_termios->c_line)   printk("c_line changed\n");
 641                 if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
 642         }
 643
 644         baudrate = tty_get_baud_rate(tty);
 645
 646         if ((tiosp->c_cflag & CBAUD) == B38400) {
 647                 if (     (port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
 648                         baudrate = 57600;
 649                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
 650                         baudrate = 115200;
 651                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
 652                         baudrate = 230400;
 653                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
 654                         baudrate = 460800;
 655                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
 656                         baudrate = (port->baud_base / port->custom_divisor);
 657         }
 658
 659         /* I recommend using THIS instead of the mess in termios (and
 660            duplicating the above code). Next we should create a clean
 661            interface towards this variable. If your card supports arbitrary
 662            baud rates, (e.g. CD1400 or 16550 based cards) then everything
 663            will be very easy..... */
 664         port->baud = baudrate;
 665
 666         /* Two timer ticks seems enough to wakeup something like SLIP driver */
 667         /* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
 668         tmp = (baudrate / 10 / HZ) * 2;
 669
 670         if (tmp <                 0) tmp = 0;
 671         if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;
 672
 673         port->wakeup_chars = tmp;
 674
 675         /* We should really wait for the characters to be all sent before
 676            changing the settings. -- CAL */
 677         rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
 678         if (rv < 0) return /* rv */;
 679
 680         rv = port->rd->set_real_termios(port);
 681         if (rv < 0) return /* rv */;
 682
 683         if ((!old_termios ||
 684              (old_termios->c_cflag & CRTSCTS)) &&
 685             !(      tiosp->c_cflag & CRTSCTS)) {
 686                 tty->stopped = 0;
 687                 gs_start(tty);
 688         }
 689
 690 #ifdef tytso_patch_94Nov25_1726
 691         /* This "makes sense", Why is it commented out? */
 692
 693         if (!(old_termios->c_cflag & CLOCAL) &&
 694             (tty->termios->c_cflag & CLOCAL))
 695                 wake_up_interruptible(&port->gs.open_wait);
 696 #endif
 697
 698         func_exit();
 699         return /* 0 */;
 700 }
 701
 702
 703
 704 /* Must be called with interrupts enabled */
 705 int gs_init_port(struct gs_port *port)
 706 {
 707         unsigned long flags;
 708
 709         func_enter ();
 710
 711         if (port->port.flags & ASYNC_INITIALIZED) {
 712                 func_exit ();
 713                 return 0;
 714         }
 715         if (!port->xmit_buf) {
 716                 /* We may sleep in get_zeroed_page() */
 717                 unsigned long tmp;
 718
 719                 tmp = get_zeroed_page(GFP_KERNEL);
 720                 spin_lock_irqsave (&port->driver_lock, flags);
 721                 if (port->xmit_buf)
 722                         free_page (tmp);
 723                 else
 724                         port->xmit_buf = (unsigned char *) tmp;
 725                 spin_unlock_irqrestore(&port->driver_lock, flags);
 726                 if (!port->xmit_buf) {
 727                         func_exit ();
 728                         return -ENOMEM;
 729                 }
 730         }
 731
 732         spin_lock_irqsave (&port->driver_lock, flags);
 733         if (port->port.tty)
 734                 clear_bit(TTY_IO_ERROR, &port->port.tty->flags);
 735         mutex_init(&port->port_write_mutex);
 736         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 737         spin_unlock_irqrestore(&port->driver_lock, flags);
 738         gs_set_termios(port->port.tty, NULL);
 739         spin_lock_irqsave (&port->driver_lock, flags);
 740         port->port.flags |= ASYNC_INITIALIZED;
 741         port->port.flags &= ~GS_TX_INTEN;
 742
 743         spin_unlock_irqrestore(&port->driver_lock, flags);
 744         func_exit ();
 745         return 0;
 746 }
 747
 748
 749 int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
 750 {
 751         struct serial_struct sio;
 752
 753         if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
 754                 return(-EFAULT);
 755
 756         if (!capable(CAP_SYS_ADMIN)) {
 757                 if ((sio.baud_base != port->baud_base) ||
 758                     (sio.close_delay != port->close_delay) ||
 759                     ((sio.flags & ~ASYNC_USR_MASK) !=
 760                      (port->port.flags & ~ASYNC_USR_MASK)))
 761                         return(-EPERM);
 762         }
 763
 764         port->port.flags = (port->port.flags & ~ASYNC_USR_MASK) |
 765                 (sio.flags & ASYNC_USR_MASK);
 766
 767         port->baud_base = sio.baud_base;
 768         port->close_delay = sio.close_delay;
 769         port->closing_wait = sio.closing_wait;
 770         port->custom_divisor = sio.custom_divisor;
 771
 772         gs_set_termios (port->port.tty, NULL);
 773
 774         return 0;
 775 }
 776
 777
 778 /*****************************************************************************/
 779
 780 /*
 781  *      Generate the serial struct info.
 782  */
 783
 784 int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
 785 {
 786         struct serial_struct    sio;
 787
 788         memset(&sio, 0, sizeof(struct serial_struct));
 789         sio.flags = port->port.flags;
 790         sio.baud_base = port->baud_base;
 791         sio.close_delay = port->close_delay;
 792         sio.closing_wait = port->closing_wait;
 793         sio.custom_divisor = port->custom_divisor;
 794         sio.hub6 = 0;
 795
 796         /* If you want you can override these. */
 797         sio.type = PORT_UNKNOWN;
 798         sio.xmit_fifo_size = -1;
 799         sio.line = -1;
 800         sio.port = -1;
 801         sio.irq = -1;
 802
 803         if (port->rd->getserial)
 804                 port->rd->getserial (port, &sio);
 805
 806         if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
 807                 return -EFAULT;
 808         return 0;
 809
 810 }
 811
 812
 813 void gs_got_break(struct gs_port *port)
 814 {
 815         func_enter ();
 816
 817         tty_insert_flip_char(port->port.tty, 0, TTY_BREAK);
 818         tty_schedule_flip(port->port.tty);
 819         if (port->port.flags & ASYNC_SAK) {
 820                 do_SAK (port->port.tty);
 821         }
 822
 823         func_exit ();
 824 }
 825
 826
 827 EXPORT_SYMBOL(gs_put_char);
 828 EXPORT_SYMBOL(gs_write);
 829 EXPORT_SYMBOL(gs_write_room);
 830 EXPORT_SYMBOL(gs_chars_in_buffer);
 831 EXPORT_SYMBOL(gs_flush_buffer);
 832 EXPORT_SYMBOL(gs_flush_chars);
 833 EXPORT_SYMBOL(gs_stop);
 834 EXPORT_SYMBOL(gs_start);
 835 EXPORT_SYMBOL(gs_hangup);
 836 EXPORT_SYMBOL(gs_block_til_ready);
 837 EXPORT_SYMBOL(gs_close);
 838 EXPORT_SYMBOL(gs_set_termios);
 839 EXPORT_SYMBOL(gs_init_port);
 840 EXPORT_SYMBOL(gs_setserial);
 841 EXPORT_SYMBOL(gs_getserial);
 842 EXPORT_SYMBOL(gs_got_break);
 843
 844 MODULE_LICENSE("GPL");