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/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 <asm/uaccess.h>
  33
  34 #define DEBUG
  35
  36 static int gs_debug;
  37
  38 #ifdef DEBUG
  39 #define gs_dprintk(f, str...) if (gs_debug & f) printk (str)
  40 #else
  41 #define gs_dprintk(f, str...) /* nothing */
  42 #endif
  43
  44 #define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __func__)
  45 #define func_exit()  gs_dprintk (GS_DEBUG_FLOW, "gs: exit  %s\n", __func__)
  46
  47 #define RS_EVENT_WRITE_WAKEUP   1
  48
  49 module_param(gs_debug, int, 0644);
  50
  51
  52 int gs_put_char(struct tty_struct * tty, unsigned char ch)
  53 {
  54         struct gs_port *port;
  55
  56         func_enter ();
  57
  58         port = tty->driver_data;
  59
  60         if (!port) return 0;
  61
  62         if (! (port->port.flags & ASYNC_INITIALIZED)) return 0;
  63
  64         /* Take a lock on the serial tranmit buffer! */
  65         mutex_lock(& port->port_write_mutex);
  66
  67         if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
  68                 /* Sorry, buffer is full, drop character. Update statistics???? -- REW */
  69                 mutex_unlock(&port->port_write_mutex);
  70                 return 0;
  71         }
  72
  73         port->xmit_buf[port->xmit_head++] = ch;
  74         port->xmit_head &= SERIAL_XMIT_SIZE - 1;
  75         port->xmit_cnt++;  /* Characters in buffer */
  76
  77         mutex_unlock(&port->port_write_mutex);
  78         func_exit ();
  79         return 1;
  80 }
  81
  82
  83 /*
  84 > Problems to take into account are:
  85 >       -1- Interrupts that empty part of the buffer.
  86 >       -2- page faults on the access to userspace.
  87 >       -3- Other processes that are also trying to do a "write".
  88 */
  89
  90 int gs_write(struct tty_struct * tty,
  91                     const unsigned char *buf, int count)
  92 {
  93         struct gs_port *port;
  94         int c, total = 0;
  95         int t;
  96
  97         func_enter ();
  98
  99         port = tty->driver_data;
 100
 101         if (!port) return 0;
 102
 103         if (! (port->port.flags & ASYNC_INITIALIZED))
 104                 return 0;
 105
 106         /* get exclusive "write" access to this port (problem 3) */
 107         /* This is not a spinlock because we can have a disk access (page
 108                  fault) in copy_from_user */
 109         mutex_lock(& port->port_write_mutex);
 110
 111         while (1) {
 112
 113                 c = count;
 114
 115                 /* This is safe because we "OWN" the "head". Noone else can
 116                    change the "head": we own the port_write_mutex. */
 117                 /* Don't overrun the end of the buffer */
 118                 t = SERIAL_XMIT_SIZE - port->xmit_head;
 119                 if (t < c) c = t;
 120
 121                 /* This is safe because the xmit_cnt can only decrease. This
 122                    would increase "t", so we might copy too little chars. */
 123                 /* Don't copy past the "head" of the buffer */
 124                 t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
 125                 if (t < c) c = t;
 126
 127                 /* Can't copy more? break out! */
 128                 if (c <= 0) break;
 129
 130                 memcpy (port->xmit_buf + port->xmit_head, buf, c);
 131
 132                 port -> xmit_cnt += c;
 133                 port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
 134                 buf += c;
 135                 count -= c;
 136                 total += c;
 137         }
 138         mutex_unlock(& port->port_write_mutex);
 139
 140         gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n",
 141                     (port->port.flags & GS_TX_INTEN)?"enabled": "disabled");
 142
 143         if (port->xmit_cnt &&
 144             !tty->stopped &&
 145             !tty->hw_stopped &&
 146             !(port->port.flags & GS_TX_INTEN)) {
 147                 port->port.flags |= GS_TX_INTEN;
 148                 port->rd->enable_tx_interrupts (port);
 149         }
 150         func_exit ();
 151         return total;
 152 }
 153
 154
 155
 156 int gs_write_room(struct tty_struct * tty)
 157 {
 158         struct gs_port *port = tty->driver_data;
 159         int ret;
 160
 161         func_enter ();
 162         ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
 163         if (ret < 0)
 164                 ret = 0;
 165         func_exit ();
 166         return ret;
 167 }
 168
 169
 170 int gs_chars_in_buffer(struct tty_struct *tty)
 171 {
 172         struct gs_port *port = tty->driver_data;
 173         func_enter ();
 174
 175         func_exit ();
 176         return port->xmit_cnt;
 177 }
 178
 179
 180 static int gs_real_chars_in_buffer(struct tty_struct *tty)
 181 {
 182         struct gs_port *port;
 183         func_enter ();
 184
 185         port = tty->driver_data;
 186
 187         if (!port->rd) return 0;
 188         if (!port->rd->chars_in_buffer) return 0;
 189
 190         func_exit ();
 191         return port->xmit_cnt + port->rd->chars_in_buffer (port);
 192 }
 193
 194
 195 static int gs_wait_tx_flushed (void * ptr, unsigned long timeout)
 196 {
 197         struct gs_port *port = ptr;
 198         unsigned long end_jiffies;
 199         int jiffies_to_transmit, charsleft = 0, rv = 0;
 200         int rcib;
 201
 202         func_enter();
 203
 204         gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
 205         if (port) {
 206                 gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n",
 207                 port->xmit_cnt, port->xmit_buf, port->port.tty);
 208         }
 209
 210         if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
 211                 gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
 212                 func_exit();
 213                 return -EINVAL;  /* This is an error which we don't know how to handle. */
 214         }
 215
 216         rcib = gs_real_chars_in_buffer(port->port.tty);
 217
 218         if(rcib <= 0) {
 219                 gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
 220                 func_exit();
 221                 return rv;
 222         }
 223         /* stop trying: now + twice the time it would normally take +  seconds */
 224         if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
 225         end_jiffies  = jiffies;
 226         if (timeout !=  MAX_SCHEDULE_TIMEOUT)
 227                 end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
 228         end_jiffies += timeout;
 229
 230         gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n",
 231                     jiffies, end_jiffies, end_jiffies-jiffies);
 232
 233         /* the expression is actually jiffies < end_jiffies, but that won't
 234            work around the wraparound. Tricky eh? */
 235         while ((charsleft = gs_real_chars_in_buffer (port->port.tty)) &&
 236                 time_after (end_jiffies, jiffies)) {
 237                 /* Units check:
 238                    chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
 239                    check! */
 240
 241                 charsleft += 16; /* Allow 16 chars more to be transmitted ... */
 242                 jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
 243                 /*                                ^^^ Round up.... */
 244                 if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;
 245
 246                 gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
 247                             "(%d chars).\n", jiffies_to_transmit, charsleft);
 248
 249                 msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
 250                 if (signal_pending (current)) {
 251                         gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: ");
 252                         rv = -EINTR;
 253                         break;
 254                 }
 255         }
 256
 257         gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft);
 258         set_current_state (TASK_RUNNING);
 259
 260         func_exit();
 261         return rv;
 262 }
 263
 264
 265
 266 void gs_flush_buffer(struct tty_struct *tty)
 267 {
 268         struct gs_port *port;
 269         unsigned long flags;
 270
 271         func_enter ();
 272
 273         port = tty->driver_data;
 274
 275         if (!port) return;
 276
 277         /* XXX Would the write semaphore do? */
 278         spin_lock_irqsave (&port->driver_lock, flags);
 279         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 280         spin_unlock_irqrestore (&port->driver_lock, flags);
 281
 282         tty_wakeup(tty);
 283         func_exit ();
 284 }
 285
 286
 287 void gs_flush_chars(struct tty_struct * tty)
 288 {
 289         struct gs_port *port;
 290
 291         func_enter ();
 292
 293         port = tty->driver_data;
 294
 295         if (!port) return;
 296
 297         if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
 298             !port->xmit_buf) {
 299                 func_exit ();
 300                 return;
 301         }
 302
 303         /* Beats me -- REW */
 304         port->port.flags |= GS_TX_INTEN;
 305         port->rd->enable_tx_interrupts (port);
 306         func_exit ();
 307 }
 308
 309
 310 void gs_stop(struct tty_struct * tty)
 311 {
 312         struct gs_port *port;
 313
 314         func_enter ();
 315
 316         port = tty->driver_data;
 317
 318         if (!port) return;
 319
 320         if (port->xmit_cnt &&
 321             port->xmit_buf &&
 322             (port->port.flags & GS_TX_INTEN) ) {
 323                 port->port.flags &= ~GS_TX_INTEN;
 324                 port->rd->disable_tx_interrupts (port);
 325         }
 326         func_exit ();
 327 }
 328
 329
 330 void gs_start(struct tty_struct * tty)
 331 {
 332         struct gs_port *port;
 333
 334         port = tty->driver_data;
 335
 336         if (!port) return;
 337
 338         if (port->xmit_cnt &&
 339             port->xmit_buf &&
 340             !(port->port.flags & GS_TX_INTEN) ) {
 341                 port->port.flags |= GS_TX_INTEN;
 342                 port->rd->enable_tx_interrupts (port);
 343         }
 344         func_exit ();
 345 }
 346
 347
 348 static void gs_shutdown_port (struct gs_port *port)
 349 {
 350         unsigned long flags;
 351
 352         func_enter();
 353
 354         if (!port) return;
 355
 356         if (!(port->port.flags & ASYNC_INITIALIZED))
 357                 return;
 358
 359         spin_lock_irqsave(&port->driver_lock, flags);
 360
 361         if (port->xmit_buf) {
 362                 free_page((unsigned long) port->xmit_buf);
 363                 port->xmit_buf = NULL;
 364         }
 365
 366         if (port->port.tty)
 367                 set_bit(TTY_IO_ERROR, &port->port.tty->flags);
 368
 369         port->rd->shutdown_port (port);
 370
 371         port->port.flags &= ~ASYNC_INITIALIZED;
 372         spin_unlock_irqrestore(&port->driver_lock, flags);
 373
 374         func_exit();
 375 }
 376
 377
 378 void gs_hangup(struct tty_struct *tty)
 379 {
 380         struct gs_port *port;
 381         unsigned long flags;
 382
 383         func_enter ();
 384
 385         port = tty->driver_data;
 386         tty = port->port.tty;
 387         if (!tty)
 388                 return;
 389
 390         gs_shutdown_port (port);
 391         spin_lock_irqsave(&port->port.lock, flags);
 392         port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
 393         port->port.tty = NULL;
 394         port->port.count = 0;
 395         spin_unlock_irqrestore(&port->port.lock, flags);
 396
 397         wake_up_interruptible(&port->port.open_wait);
 398         func_exit ();
 399 }
 400
 401
 402 int gs_block_til_ready(void *port_, struct file * filp)
 403 {
 404         struct gs_port *gp = port_;
 405         struct tty_port *port = &gp->port;
 406         DECLARE_WAITQUEUE(wait, current);
 407         int    retval;
 408         int    do_clocal = 0;
 409         int    CD;
 410         struct tty_struct *tty;
 411         unsigned long flags;
 412
 413         func_enter ();
 414
 415         if (!port) return 0;
 416
 417         tty = port->tty;
 418
 419         gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
 420         /*
 421          * If the device is in the middle of being closed, then block
 422          * until it's done, and then try again.
 423          */
 424         if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
 425                 interruptible_sleep_on(&port->close_wait);
 426                 if (port->flags & ASYNC_HUP_NOTIFY)
 427                         return -EAGAIN;
 428                 else
 429                         return -ERESTARTSYS;
 430         }
 431
 432         gs_dprintk (GS_DEBUG_BTR, "after hung up\n");
 433
 434         /*
 435          * If non-blocking mode is set, or the port is not enabled,
 436          * then make the check up front and then exit.
 437          */
 438         if ((filp->f_flags & O_NONBLOCK) ||
 439             (tty->flags & (1 << TTY_IO_ERROR))) {
 440                 port->flags |= ASYNC_NORMAL_ACTIVE;
 441                 return 0;
 442         }
 443
 444         gs_dprintk (GS_DEBUG_BTR, "after nonblock\n");
 445
 446         if (C_CLOCAL(tty))
 447                 do_clocal = 1;
 448
 449         /*
 450          * Block waiting for the carrier detect and the line to become
 451          * free (i.e., not in use by the callout).  While we are in
 452          * this loop, port->count is dropped by one, so that
 453          * rs_close() knows when to free things.  We restore it upon
 454          * exit, either normal or abnormal.
 455          */
 456         retval = 0;
 457
 458         add_wait_queue(&port->open_wait, &wait);
 459
 460         gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
 461         spin_lock_irqsave(&port->lock, flags);
 462         if (!tty_hung_up_p(filp)) {
 463                 port->count--;
 464         }
 465         port->blocked_open++;
 466         spin_unlock_irqrestore(&port->lock, flags);
 467         while (1) {
 468                 CD = tty_port_carrier_raised(port);
 469                 gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
 470                 set_current_state (TASK_INTERRUPTIBLE);
 471                 if (tty_hung_up_p(filp) ||
 472                     !(port->flags & ASYNC_INITIALIZED)) {
 473                         if (port->flags & ASYNC_HUP_NOTIFY)
 474                                 retval = -EAGAIN;
 475                         else
 476                                 retval = -ERESTARTSYS;
 477                         break;
 478                 }
 479                 if (!(port->flags & ASYNC_CLOSING) &&
 480                     (do_clocal || CD))
 481                         break;
 482                 gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
 483                 (int)signal_pending (current), *(long*)(&current->blocked));
 484                 if (signal_pending(current)) {
 485                         retval = -ERESTARTSYS;
 486                         break;
 487                 }
 488                 schedule();
 489         }
 490         gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
 491                     port->blocked_open);
 492         set_current_state (TASK_RUNNING);
 493         remove_wait_queue(&port->open_wait, &wait);
 494
 495         spin_lock_irqsave(&port->lock, flags);
 496         if (!tty_hung_up_p(filp)) {
 497                 port->count++;
 498         }
 499         port->blocked_open--;
 500         if (retval == 0)
 501                 port->flags |= ASYNC_NORMAL_ACTIVE;
 502         spin_unlock_irqrestore(&port->lock, flags);
 503         func_exit ();
 504         return retval;
 505 }
 506
 507
 508 void gs_close(struct tty_struct * tty, struct file * filp)
 509 {
 510         unsigned long flags;
 511         struct gs_port *port;
 512
 513         func_enter ();
 514
 515         port = tty->driver_data;
 516
 517         if (!port) return;
 518
 519         if (!port->port.tty) {
 520                 /* This seems to happen when this is called from vhangup. */
 521                 gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->port.tty is NULL\n");
 522                 port->port.tty = tty;
 523         }
 524
 525         spin_lock_irqsave(&port->port.lock, flags);
 526
 527         if (tty_hung_up_p(filp)) {
 528                 spin_unlock_irqrestore(&port->port.lock, flags);
 529                 if (port->rd->hungup)
 530                         port->rd->hungup (port);
 531                 func_exit ();
 532                 return;
 533         }
 534
 535         if ((tty->count == 1) && (port->port.count != 1)) {
 536                 printk(KERN_ERR "gs: gs_close port %p: bad port count;"
 537                        " tty->count is 1, port count is %d\n", port, port->port.count);
 538                 port->port.count = 1;
 539         }
 540         if (--port->port.count < 0) {
 541                 printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->port.count);
 542                 port->port.count = 0;
 543         }
 544
 545         if (port->port.count) {
 546                 gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->port.count);
 547                 spin_unlock_irqrestore(&port->port.lock, flags);
 548                 func_exit ();
 549                 return;
 550         }
 551         port->port.flags |= ASYNC_CLOSING;
 552
 553         /*
 554          * Now we wait for the transmit buffer to clear; and we notify
 555          * the line discipline to only process XON/XOFF characters.
 556          */
 557         tty->closing = 1;
 558         /* if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 559            tty_wait_until_sent(tty, port->closing_wait); */
 560
 561         /*
 562          * At this point we stop accepting input.  To do this, we
 563          * disable the receive line status interrupts, and tell the
 564          * interrupt driver to stop checking the data ready bit in the
 565          * line status register.
 566          */
 567
 568         spin_lock_irqsave(&port->driver_lock, flags);
 569         port->rd->disable_rx_interrupts (port);
 570         spin_unlock_irqrestore(&port->driver_lock, flags);
 571         spin_unlock_irqrestore(&port->port.lock, flags);
 572
 573         /* close has no way of returning "EINTR", so discard return value */
 574         if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
 575                 gs_wait_tx_flushed (port, port->closing_wait);
 576
 577         port->port.flags &= ~GS_ACTIVE;
 578
 579         gs_flush_buffer(tty);
 580
 581         tty_ldisc_flush(tty);
 582         tty->closing = 0;
 583
 584         spin_lock_irqsave(&port->driver_lock, flags);
 585         port->event = 0;
 586         port->rd->close (port);
 587         port->rd->shutdown_port (port);
 588         spin_unlock_irqrestore(&port->driver_lock, flags);
 589
 590         spin_lock_irqsave(&port->port.lock, flags);
 591         port->port.tty = NULL;
 592
 593         if (port->port.blocked_open) {
 594                 if (port->close_delay) {
 595                         spin_unlock_irqrestore(&port->port.lock, flags);
 596                         msleep_interruptible(jiffies_to_msecs(port->close_delay));
 597                         spin_lock_irqsave(&port->port.lock, flags);
 598                 }
 599                 wake_up_interruptible(&port->port.open_wait);
 600         }
 601         port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
 602         spin_unlock_irqrestore(&port->port.lock, flags);
 603         wake_up_interruptible(&port->port.close_wait);
 604
 605         func_exit ();
 606 }
 607
 608
 609 void gs_set_termios (struct tty_struct * tty,
 610                      struct ktermios * old_termios)
 611 {
 612         struct gs_port *port;
 613         int baudrate, tmp, rv;
 614         struct ktermios *tiosp;
 615
 616         func_enter();
 617
 618         port = tty->driver_data;
 619
 620         if (!port) return;
 621         if (!port->port.tty) {
 622                 /* This seems to happen when this is called after gs_close. */
 623                 gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->port.tty is NULL\n");
 624                 port->port.tty = tty;
 625         }
 626
 627
 628         tiosp = tty->termios;
 629
 630         if (gs_debug & GS_DEBUG_TERMIOS) {
 631                 gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
 632         }
 633
 634         if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
 635                 if(tiosp->c_iflag != old_termios->c_iflag)  printk("c_iflag changed\n");
 636                 if(tiosp->c_oflag != old_termios->c_oflag)  printk("c_oflag changed\n");
 637                 if(tiosp->c_cflag != old_termios->c_cflag)  printk("c_cflag changed\n");
 638                 if(tiosp->c_lflag != old_termios->c_lflag)  printk("c_lflag changed\n");
 639                 if(tiosp->c_line  != old_termios->c_line)   printk("c_line changed\n");
 640                 if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
 641         }
 642
 643         baudrate = tty_get_baud_rate(tty);
 644
 645         if ((tiosp->c_cflag & CBAUD) == B38400) {
 646                 if (     (port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
 647                         baudrate = 57600;
 648                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
 649                         baudrate = 115200;
 650                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
 651                         baudrate = 230400;
 652                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
 653                         baudrate = 460800;
 654                 else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
 655                         baudrate = (port->baud_base / port->custom_divisor);
 656         }
 657
 658         /* I recommend using THIS instead of the mess in termios (and
 659            duplicating the above code). Next we should create a clean
 660            interface towards this variable. If your card supports arbitrary
 661            baud rates, (e.g. CD1400 or 16550 based cards) then everything
 662            will be very easy..... */
 663         port->baud = baudrate;
 664
 665         /* Two timer ticks seems enough to wakeup something like SLIP driver */
 666         /* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
 667         tmp = (baudrate / 10 / HZ) * 2;
 668
 669         if (tmp <                 0) tmp = 0;
 670         if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;
 671
 672         port->wakeup_chars = tmp;
 673
 674         /* We should really wait for the characters to be all sent before
 675            changing the settings. -- CAL */
 676         rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
 677         if (rv < 0) return /* rv */;
 678
 679         rv = port->rd->set_real_termios(port);
 680         if (rv < 0) return /* rv */;
 681
 682         if ((!old_termios ||
 683              (old_termios->c_cflag & CRTSCTS)) &&
 684             !(      tiosp->c_cflag & CRTSCTS)) {
 685                 tty->stopped = 0;
 686                 gs_start(tty);
 687         }
 688
 689 #ifdef tytso_patch_94Nov25_1726
 690         /* This "makes sense", Why is it commented out? */
 691
 692         if (!(old_termios->c_cflag & CLOCAL) &&
 693             (tty->termios->c_cflag & CLOCAL))
 694                 wake_up_interruptible(&port->gs.open_wait);
 695 #endif
 696
 697         func_exit();
 698         return /* 0 */;
 699 }
 700
 701
 702
 703 /* Must be called with interrupts enabled */
 704 int gs_init_port(struct gs_port *port)
 705 {
 706         unsigned long flags;
 707
 708         func_enter ();
 709
 710         if (port->port.flags & ASYNC_INITIALIZED) {
 711                 func_exit ();
 712                 return 0;
 713         }
 714         if (!port->xmit_buf) {
 715                 /* We may sleep in get_zeroed_page() */
 716                 unsigned long tmp;
 717
 718                 tmp = get_zeroed_page(GFP_KERNEL);
 719                 spin_lock_irqsave (&port->driver_lock, flags);
 720                 if (port->xmit_buf)
 721                         free_page (tmp);
 722                 else
 723                         port->xmit_buf = (unsigned char *) tmp;
 724                 spin_unlock_irqrestore(&port->driver_lock, flags);
 725                 if (!port->xmit_buf) {
 726                         func_exit ();
 727                         return -ENOMEM;
 728                 }
 729         }
 730
 731         spin_lock_irqsave (&port->driver_lock, flags);
 732         if (port->port.tty)
 733                 clear_bit(TTY_IO_ERROR, &port->port.tty->flags);
 734         mutex_init(&port->port_write_mutex);
 735         port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
 736         spin_unlock_irqrestore(&port->driver_lock, flags);
 737         gs_set_termios(port->port.tty, NULL);
 738         spin_lock_irqsave (&port->driver_lock, flags);
 739         port->port.flags |= ASYNC_INITIALIZED;
 740         port->port.flags &= ~GS_TX_INTEN;
 741
 742         spin_unlock_irqrestore(&port->driver_lock, flags);
 743         func_exit ();
 744         return 0;
 745 }
 746
 747
 748 int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
 749 {
 750         struct serial_struct sio;
 751
 752         if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
 753                 return(-EFAULT);
 754
 755         if (!capable(CAP_SYS_ADMIN)) {
 756                 if ((sio.baud_base != port->baud_base) ||
 757                     (sio.close_delay != port->close_delay) ||
 758                     ((sio.flags & ~ASYNC_USR_MASK) !=
 759                      (port->port.flags & ~ASYNC_USR_MASK)))
 760                         return(-EPERM);
 761         }
 762
 763         port->port.flags = (port->port.flags & ~ASYNC_USR_MASK) |
 764                 (sio.flags & ASYNC_USR_MASK);
 765
 766         port->baud_base = sio.baud_base;
 767         port->close_delay = sio.close_delay;
 768         port->closing_wait = sio.closing_wait;
 769         port->custom_divisor = sio.custom_divisor;
 770
 771         gs_set_termios (port->port.tty, NULL);
 772
 773         return 0;
 774 }
 775
 776
 777 /*****************************************************************************/
 778
 779 /*
 780  *      Generate the serial struct info.
 781  */
 782
 783 int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
 784 {
 785         struct serial_struct    sio;
 786
 787         memset(&sio, 0, sizeof(struct serial_struct));
 788         sio.flags = port->port.flags;
 789         sio.baud_base = port->baud_base;
 790         sio.close_delay = port->close_delay;
 791         sio.closing_wait = port->closing_wait;
 792         sio.custom_divisor = port->custom_divisor;
 793         sio.hub6 = 0;
 794
 795         /* If you want you can override these. */
 796         sio.type = PORT_UNKNOWN;
 797         sio.xmit_fifo_size = -1;
 798         sio.line = -1;
 799         sio.port = -1;
 800         sio.irq = -1;
 801
 802         if (port->rd->getserial)
 803                 port->rd->getserial (port, &sio);
 804
 805         if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
 806                 return -EFAULT;
 807         return 0;
 808
 809 }
 810
 811
 812 void gs_got_break(struct gs_port *port)
 813 {
 814         func_enter ();
 815
 816         tty_insert_flip_char(port->port.tty, 0, TTY_BREAK);
 817         tty_schedule_flip(port->port.tty);
 818         if (port->port.flags & ASYNC_SAK) {
 819                 do_SAK (port->port.tty);
 820         }
 821
 822         func_exit ();
 823 }
 824
 825
 826 EXPORT_SYMBOL(gs_put_char);
 827 EXPORT_SYMBOL(gs_write);
 828 EXPORT_SYMBOL(gs_write_room);
 829 EXPORT_SYMBOL(gs_chars_in_buffer);
 830 EXPORT_SYMBOL(gs_flush_buffer);
 831 EXPORT_SYMBOL(gs_flush_chars);
 832 EXPORT_SYMBOL(gs_stop);
 833 EXPORT_SYMBOL(gs_start);
 834 EXPORT_SYMBOL(gs_hangup);
 835 EXPORT_SYMBOL(gs_block_til_ready);
 836 EXPORT_SYMBOL(gs_close);
 837 EXPORT_SYMBOL(gs_set_termios);
 838 EXPORT_SYMBOL(gs_init_port);
 839 EXPORT_SYMBOL(gs_setserial);
 840 EXPORT_SYMBOL(gs_getserial);
 841 EXPORT_SYMBOL(gs_got_break);
 842
 843 MODULE_LICENSE("GPL");