drivers/serial/serial_core.c

   1 /*
   2  *  linux/drivers/char/core.c
   3  *
   4  *  Driver core for serial ports
   5  *
   6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   7  *
   8  *  Copyright 1999 ARM Limited
   9  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24  */
  25 #include <linux/config.h>
  26 #include <linux/module.h>
  27 #include <linux/tty.h>
  28 #include <linux/slab.h>
  29 #include <linux/init.h>
  30 #include <linux/console.h>
  31 #include <linux/serial_core.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/device.h>
  34 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
  35 #include <linux/delay.h>
  36
  37 #include <asm/irq.h>
  38 #include <asm/uaccess.h>
  39
  40 #undef  DEBUG
  41 #ifdef DEBUG
  42 #define DPRINTK(x...)   printk(x)
  43 #else
  44 #define DPRINTK(x...)   do { } while (0)
  45 #endif
  46
  47 /*
  48  * This is used to lock changes in serial line configuration.
  49  */
  50 static DECLARE_MUTEX(port_sem);
  51
  52 #define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
  53
  54 #define uart_users(state)       ((state)->count + ((state)->info ? (state)->info->blocked_open : 0))
  55
  56 #ifdef CONFIG_SERIAL_CORE_CONSOLE
  57 #define uart_console(port)      ((port)->cons && (port)->cons->index == (port)->line)
  58 #else
  59 #define uart_console(port)      (0)
  60 #endif
  61
  62 static void uart_change_speed(struct uart_state *state, struct termios *old_termios);
  63 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
  64 static void uart_change_pm(struct uart_state *state, int pm_state);
  65
  66 /*
  67  * This routine is used by the interrupt handler to schedule processing in
  68  * the software interrupt portion of the driver.
  69  */
  70 void uart_write_wakeup(struct uart_port *port)
  71 {
  72         struct uart_info *info = port->info;
  73         tasklet_schedule(&info->tlet);
  74 }
  75
  76 static void uart_stop(struct tty_struct *tty)
  77 {
  78         struct uart_state *state = tty->driver_data;
  79         struct uart_port *port = state->port;
  80         unsigned long flags;
  81
  82         spin_lock_irqsave(&port->lock, flags);
  83         port->ops->stop_tx(port, 1);
  84         spin_unlock_irqrestore(&port->lock, flags);
  85 }
  86
  87 static void __uart_start(struct tty_struct *tty)
  88 {
  89         struct uart_state *state = tty->driver_data;
  90         struct uart_port *port = state->port;
  91
  92         if (!uart_circ_empty(&state->info->xmit) && state->info->xmit.buf &&
  93             !tty->stopped && !tty->hw_stopped)
  94                 port->ops->start_tx(port, 1);
  95 }
  96
  97 static void uart_start(struct tty_struct *tty)
  98 {
  99         struct uart_state *state = tty->driver_data;
 100         struct uart_port *port = state->port;
 101         unsigned long flags;
 102
 103         spin_lock_irqsave(&port->lock, flags);
 104         __uart_start(tty);
 105         spin_unlock_irqrestore(&port->lock, flags);
 106 }
 107
 108 static void uart_tasklet_action(unsigned long data)
 109 {
 110         struct uart_state *state = (struct uart_state *)data;
 111         tty_wakeup(state->info->tty);
 112 }
 113
 114 static inline void
 115 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
 116 {
 117         unsigned long flags;
 118         unsigned int old;
 119
 120         spin_lock_irqsave(&port->lock, flags);
 121         old = port->mctrl;
 122         port->mctrl = (old & ~clear) | set;
 123         if (old != port->mctrl)
 124                 port->ops->set_mctrl(port, port->mctrl);
 125         spin_unlock_irqrestore(&port->lock, flags);
 126 }
 127
 128 #define uart_set_mctrl(port,set)        uart_update_mctrl(port,set,0)
 129 #define uart_clear_mctrl(port,clear)    uart_update_mctrl(port,0,clear)
 130
 131 /*
 132  * Startup the port.  This will be called once per open.  All calls
 133  * will be serialised by the per-port semaphore.
 134  */
 135 static int uart_startup(struct uart_state *state, int init_hw)
 136 {
 137         struct uart_info *info = state->info;
 138         struct uart_port *port = state->port;
 139         unsigned long page;
 140         int retval = 0;
 141
 142         if (info->flags & UIF_INITIALIZED)
 143                 return 0;
 144
 145         /*
 146          * Set the TTY IO error marker - we will only clear this
 147          * once we have successfully opened the port.  Also set
 148          * up the tty->alt_speed kludge
 149          */
 150         if (info->tty)
 151                 set_bit(TTY_IO_ERROR, &info->tty->flags);
 152
 153         if (port->type == PORT_UNKNOWN)
 154                 return 0;
 155
 156         /*
 157          * Initialise and allocate the transmit and temporary
 158          * buffer.
 159          */
 160         if (!info->xmit.buf) {
 161                 page = get_zeroed_page(GFP_KERNEL);
 162                 if (!page)
 163                         return -ENOMEM;
 164
 165                 info->xmit.buf = (unsigned char *) page;
 166                 uart_circ_clear(&info->xmit);
 167         }
 168
 169         retval = port->ops->startup(port);
 170         if (retval == 0) {
 171                 if (init_hw) {
 172                         /*
 173                          * Initialise the hardware port settings.
 174                          */
 175                         uart_change_speed(state, NULL);
 176
 177                         /*
 178                          * Setup the RTS and DTR signals once the
 179                          * port is open and ready to respond.
 180                          */
 181                         if (info->tty->termios->c_cflag & CBAUD)
 182                                 uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
 183                 }
 184
 185                 if (info->flags & UIF_CTS_FLOW) {
 186                         spin_lock_irq(&port->lock);
 187                         if (!(port->ops->get_mctrl(port) & TIOCM_CTS))
 188                                 info->tty->hw_stopped = 1;
 189                         spin_unlock_irq(&port->lock);
 190                 }
 191
 192                 info->flags |= UIF_INITIALIZED;
 193
 194                 clear_bit(TTY_IO_ERROR, &info->tty->flags);
 195         }
 196
 197         if (retval && capable(CAP_SYS_ADMIN))
 198                 retval = 0;
 199
 200         return retval;
 201 }
 202
 203 /*
 204  * This routine will shutdown a serial port; interrupts are disabled, and
 205  * DTR is dropped if the hangup on close termio flag is on.  Calls to
 206  * uart_shutdown are serialised by the per-port semaphore.
 207  */
 208 static void uart_shutdown(struct uart_state *state)
 209 {
 210         struct uart_info *info = state->info;
 211         struct uart_port *port = state->port;
 212
 213         if (!(info->flags & UIF_INITIALIZED))
 214                 return;
 215
 216         /*
 217          * Turn off DTR and RTS early.
 218          */
 219         if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
 220                 uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
 221
 222         /*
 223          * clear delta_msr_wait queue to avoid mem leaks: we may free
 224          * the irq here so the queue might never be woken up.  Note
 225          * that we won't end up waiting on delta_msr_wait again since
 226          * any outstanding file descriptors should be pointing at
 227          * hung_up_tty_fops now.
 228          */
 229         wake_up_interruptible(&info->delta_msr_wait);
 230
 231         /*
 232          * Free the IRQ and disable the port.
 233          */
 234         port->ops->shutdown(port);
 235
 236         /*
 237          * Ensure that the IRQ handler isn't running on another CPU.
 238          */
 239         synchronize_irq(port->irq);
 240
 241         /*
 242          * Free the transmit buffer page.
 243          */
 244         if (info->xmit.buf) {
 245                 free_page((unsigned long)info->xmit.buf);
 246                 info->xmit.buf = NULL;
 247         }
 248
 249         /*
 250          * kill off our tasklet
 251          */
 252         tasklet_kill(&info->tlet);
 253         if (info->tty)
 254                 set_bit(TTY_IO_ERROR, &info->tty->flags);
 255
 256         info->flags &= ~UIF_INITIALIZED;
 257 }
 258
 259 /**
 260  *      uart_update_timeout - update per-port FIFO timeout.
 261  *      @port:  uart_port structure describing the port
 262  *      @cflag: termios cflag value
 263  *      @baud:  speed of the port
 264  *
 265  *      Set the port FIFO timeout value.  The @cflag value should
 266  *      reflect the actual hardware settings.
 267  */
 268 void
 269 uart_update_timeout(struct uart_port *port, unsigned int cflag,
 270                     unsigned int baud)
 271 {
 272         unsigned int bits;
 273
 274         /* byte size and parity */
 275         switch (cflag & CSIZE) {
 276         case CS5:
 277                 bits = 7;
 278                 break;
 279         case CS6:
 280                 bits = 8;
 281                 break;
 282         case CS7:
 283                 bits = 9;
 284                 break;
 285         default:
 286                 bits = 10;
 287                 break; // CS8
 288         }
 289
 290         if (cflag & CSTOPB)
 291                 bits++;
 292         if (cflag & PARENB)
 293                 bits++;
 294
 295         /*
 296          * The total number of bits to be transmitted in the fifo.
 297          */
 298         bits = bits * port->fifosize;
 299
 300         /*
 301          * Figure the timeout to send the above number of bits.
 302          * Add .02 seconds of slop
 303          */
 304         port->timeout = (HZ * bits) / baud + HZ/50;
 305 }
 306
 307 EXPORT_SYMBOL(uart_update_timeout);
 308
 309 /**
 310  *      uart_get_baud_rate - return baud rate for a particular port
 311  *      @port: uart_port structure describing the port in question.
 312  *      @termios: desired termios settings.
 313  *      @old: old termios (or NULL)
 314  *      @min: minimum acceptable baud rate
 315  *      @max: maximum acceptable baud rate
 316  *
 317  *      Decode the termios structure into a numeric baud rate,
 318  *      taking account of the magic 38400 baud rate (with spd_*
 319  *      flags), and mapping the %B0 rate to 9600 baud.
 320  *
 321  *      If the new baud rate is invalid, try the old termios setting.
 322  *      If it's still invalid, we try 9600 baud.
 323  *
 324  *      Update the @termios structure to reflect the baud rate
 325  *      we're actually going to be using.
 326  */
 327 unsigned int
 328 uart_get_baud_rate(struct uart_port *port, struct termios *termios,
 329                    struct termios *old, unsigned int min, unsigned int max)
 330 {
 331         unsigned int try, baud, altbaud = 38400;
 332         unsigned int flags = port->flags & UPF_SPD_MASK;
 333
 334         if (flags == UPF_SPD_HI)
 335                 altbaud = 57600;
 336         if (flags == UPF_SPD_VHI)
 337                 altbaud = 115200;
 338         if (flags == UPF_SPD_SHI)
 339                 altbaud = 230400;
 340         if (flags == UPF_SPD_WARP)
 341                 altbaud = 460800;
 342
 343         for (try = 0; try < 2; try++) {
 344                 baud = tty_termios_baud_rate(termios);
 345
 346                 /*
 347                  * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
 348                  * Die! Die! Die!
 349                  */
 350                 if (baud == 38400)
 351                         baud = altbaud;
 352
 353                 /*
 354                  * Special case: B0 rate.
 355                  */
 356                 if (baud == 0)
 357                         baud = 9600;
 358
 359                 if (baud >= min && baud <= max)
 360                         return baud;
 361
 362                 /*
 363                  * Oops, the quotient was zero.  Try again with
 364                  * the old baud rate if possible.
 365                  */
 366                 termios->c_cflag &= ~CBAUD;
 367                 if (old) {
 368                         termios->c_cflag |= old->c_cflag & CBAUD;
 369                         old = NULL;
 370                         continue;
 371                 }
 372
 373                 /*
 374                  * As a last resort, if the quotient is zero,
 375                  * default to 9600 bps
 376                  */
 377                 termios->c_cflag |= B9600;
 378         }
 379
 380         return 0;
 381 }
 382
 383 EXPORT_SYMBOL(uart_get_baud_rate);
 384
 385 /**
 386  *      uart_get_divisor - return uart clock divisor
 387  *      @port: uart_port structure describing the port.
 388  *      @baud: desired baud rate
 389  *
 390  *      Calculate the uart clock divisor for the port.
 391  */
 392 unsigned int
 393 uart_get_divisor(struct uart_port *port, unsigned int baud)
 394 {
 395         unsigned int quot;
 396
 397         /*
 398          * Old custom speed handling.
 399          */
 400         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 401                 quot = port->custom_divisor;
 402         else
 403                 quot = (port->uartclk + (8 * baud)) / (16 * baud);
 404
 405         return quot;
 406 }
 407
 408 EXPORT_SYMBOL(uart_get_divisor);
 409
 410 static void
 411 uart_change_speed(struct uart_state *state, struct termios *old_termios)
 412 {
 413         struct tty_struct *tty = state->info->tty;
 414         struct uart_port *port = state->port;
 415         struct termios *termios;
 416
 417         /*
 418          * If we have no tty, termios, or the port does not exist,
 419          * then we can't set the parameters for this port.
 420          */
 421         if (!tty || !tty->termios || port->type == PORT_UNKNOWN)
 422                 return;
 423
 424         termios = tty->termios;
 425
 426         /*
 427          * Set flags based on termios cflag
 428          */
 429         if (termios->c_cflag & CRTSCTS)
 430                 state->info->flags |= UIF_CTS_FLOW;
 431         else
 432                 state->info->flags &= ~UIF_CTS_FLOW;
 433
 434         if (termios->c_cflag & CLOCAL)
 435                 state->info->flags &= ~UIF_CHECK_CD;
 436         else
 437                 state->info->flags |= UIF_CHECK_CD;
 438
 439         port->ops->set_termios(port, termios, old_termios);
 440 }
 441
 442 static inline void
 443 __uart_put_char(struct uart_port *port, struct circ_buf *circ, unsigned char c)
 444 {
 445         unsigned long flags;
 446
 447         if (!circ->buf)
 448                 return;
 449
 450         spin_lock_irqsave(&port->lock, flags);
 451         if (uart_circ_chars_free(circ) != 0) {
 452                 circ->buf[circ->head] = c;
 453                 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
 454         }
 455         spin_unlock_irqrestore(&port->lock, flags);
 456 }
 457
 458 static void uart_put_char(struct tty_struct *tty, unsigned char ch)
 459 {
 460         struct uart_state *state = tty->driver_data;
 461
 462         __uart_put_char(state->port, &state->info->xmit, ch);
 463 }
 464
 465 static void uart_flush_chars(struct tty_struct *tty)
 466 {
 467         uart_start(tty);
 468 }
 469
 470 static int
 471 uart_write(struct tty_struct *tty, const unsigned char * buf, int count)
 472 {
 473         struct uart_state *state = tty->driver_data;
 474         struct uart_port *port = state->port;
 475         struct circ_buf *circ = &state->info->xmit;
 476         unsigned long flags;
 477         int c, ret = 0;
 478
 479         if (!circ->buf)
 480                 return 0;
 481
 482         spin_lock_irqsave(&port->lock, flags);
 483         while (1) {
 484                 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
 485                 if (count < c)
 486                         c = count;
 487                 if (c <= 0)
 488                         break;
 489                 memcpy(circ->buf + circ->head, buf, c);
 490                 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
 491                 buf += c;
 492                 count -= c;
 493                 ret += c;
 494         }
 495         spin_unlock_irqrestore(&port->lock, flags);
 496
 497         uart_start(tty);
 498         return ret;
 499 }
 500
 501 static int uart_write_room(struct tty_struct *tty)
 502 {
 503         struct uart_state *state = tty->driver_data;
 504
 505         return uart_circ_chars_free(&state->info->xmit);
 506 }
 507
 508 static int uart_chars_in_buffer(struct tty_struct *tty)
 509 {
 510         struct uart_state *state = tty->driver_data;
 511
 512         return uart_circ_chars_pending(&state->info->xmit);
 513 }
 514
 515 static void uart_flush_buffer(struct tty_struct *tty)
 516 {
 517         struct uart_state *state = tty->driver_data;
 518         struct uart_port *port = state->port;
 519         unsigned long flags;
 520
 521         DPRINTK("uart_flush_buffer(%d) called\n", tty->index);
 522
 523         spin_lock_irqsave(&port->lock, flags);
 524         uart_circ_clear(&state->info->xmit);
 525         spin_unlock_irqrestore(&port->lock, flags);
 526         tty_wakeup(tty);
 527 }
 528
 529 /*
 530  * This function is used to send a high-priority XON/XOFF character to
 531  * the device
 532  */
 533 static void uart_send_xchar(struct tty_struct *tty, char ch)
 534 {
 535         struct uart_state *state = tty->driver_data;
 536         struct uart_port *port = state->port;
 537         unsigned long flags;
 538
 539         if (port->ops->send_xchar)
 540                 port->ops->send_xchar(port, ch);
 541         else {
 542                 port->x_char = ch;
 543                 if (ch) {
 544                         spin_lock_irqsave(&port->lock, flags);
 545                         port->ops->start_tx(port, 0);
 546                         spin_unlock_irqrestore(&port->lock, flags);
 547                 }
 548         }
 549 }
 550
 551 static void uart_throttle(struct tty_struct *tty)
 552 {
 553         struct uart_state *state = tty->driver_data;
 554
 555         if (I_IXOFF(tty))
 556                 uart_send_xchar(tty, STOP_CHAR(tty));
 557
 558         if (tty->termios->c_cflag & CRTSCTS)
 559                 uart_clear_mctrl(state->port, TIOCM_RTS);
 560 }
 561
 562 static void uart_unthrottle(struct tty_struct *tty)
 563 {
 564         struct uart_state *state = tty->driver_data;
 565         struct uart_port *port = state->port;
 566
 567         if (I_IXOFF(tty)) {
 568                 if (port->x_char)
 569                         port->x_char = 0;
 570                 else
 571                         uart_send_xchar(tty, START_CHAR(tty));
 572         }
 573
 574         if (tty->termios->c_cflag & CRTSCTS)
 575                 uart_set_mctrl(port, TIOCM_RTS);
 576 }
 577
 578 static int uart_get_info(struct uart_state *state,
 579                          struct serial_struct __user *retinfo)
 580 {
 581         struct uart_port *port = state->port;
 582         struct serial_struct tmp;
 583
 584         memset(&tmp, 0, sizeof(tmp));
 585         tmp.type            = port->type;
 586         tmp.line            = port->line;
 587         tmp.port            = port->iobase;
 588         if (HIGH_BITS_OFFSET)
 589                 tmp.port_high = (long) port->iobase >> HIGH_BITS_OFFSET;
 590         tmp.irq             = port->irq;
 591         tmp.flags           = port->flags;
 592         tmp.xmit_fifo_size  = port->fifosize;
 593         tmp.baud_base       = port->uartclk / 16;
 594         tmp.close_delay     = state->close_delay / 10;
 595         tmp.closing_wait    = state->closing_wait == USF_CLOSING_WAIT_NONE ?
 596                                 ASYNC_CLOSING_WAIT_NONE :
 597                                 state->closing_wait / 10;
 598         tmp.custom_divisor  = port->custom_divisor;
 599         tmp.hub6            = port->hub6;
 600         tmp.io_type         = port->iotype;
 601         tmp.iomem_reg_shift = port->regshift;
 602         tmp.iomem_base      = (void *)port->mapbase;
 603
 604         if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
 605                 return -EFAULT;
 606         return 0;
 607 }
 608
 609 static int uart_set_info(struct uart_state *state,
 610                          struct serial_struct __user *newinfo)
 611 {
 612         struct serial_struct new_serial;
 613         struct uart_port *port = state->port;
 614         unsigned long new_port;
 615         unsigned int change_irq, change_port, old_flags, closing_wait;
 616         unsigned int old_custom_divisor, close_delay;
 617         int retval = 0;
 618
 619         if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
 620                 return -EFAULT;
 621
 622         new_port = new_serial.port;
 623         if (HIGH_BITS_OFFSET)
 624                 new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;
 625
 626         new_serial.irq = irq_canonicalize(new_serial.irq);
 627         close_delay = new_serial.close_delay * 10;
 628         closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 629                         USF_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
 630
 631         /*
 632          * This semaphore protects state->count.  It is also
 633          * very useful to prevent opens.  Also, take the
 634          * port configuration semaphore to make sure that a
 635          * module insertion/removal doesn't change anything
 636          * under us.
 637          */
 638         down(&state->sem);
 639
 640         change_irq  = new_serial.irq != port->irq;
 641
 642         /*
 643          * Since changing the 'type' of the port changes its resource
 644          * allocations, we should treat type changes the same as
 645          * IO port changes.
 646          */
 647         change_port = new_port != port->iobase ||
 648                       (unsigned long)new_serial.iomem_base != port->mapbase ||
 649                       new_serial.hub6 != port->hub6 ||
 650                       new_serial.io_type != port->iotype ||
 651                       new_serial.iomem_reg_shift != port->regshift ||
 652                       new_serial.type != port->type;
 653
 654         old_flags = port->flags;
 655         old_custom_divisor = port->custom_divisor;
 656
 657         if (!capable(CAP_SYS_ADMIN)) {
 658                 retval = -EPERM;
 659                 if (change_irq || change_port ||
 660                     (new_serial.baud_base != port->uartclk / 16) ||
 661                     (close_delay != state->close_delay) ||
 662                     (closing_wait != state->closing_wait) ||
 663                     (new_serial.xmit_fifo_size != port->fifosize) ||
 664                     (((new_serial.flags ^ old_flags) & ~UPF_USR_MASK) != 0))
 665                         goto exit;
 666                 port->flags = ((port->flags & ~UPF_USR_MASK) |
 667                                (new_serial.flags & UPF_USR_MASK));
 668                 port->custom_divisor = new_serial.custom_divisor;
 669                 goto check_and_exit;
 670         }
 671
 672         /*
 673          * Ask the low level driver to verify the settings.
 674          */
 675         if (port->ops->verify_port)
 676                 retval = port->ops->verify_port(port, &new_serial);
 677
 678         if ((new_serial.irq >= NR_IRQS) || (new_serial.irq < 0) ||
 679             (new_serial.baud_base < 9600))
 680                 retval = -EINVAL;
 681
 682         if (retval)
 683                 goto exit;
 684
 685         if (change_port || change_irq) {
 686                 retval = -EBUSY;
 687
 688                 /*
 689                  * Make sure that we are the sole user of this port.
 690                  */
 691                 if (uart_users(state) > 1)
 692                         goto exit;
 693
 694                 /*
 695                  * We need to shutdown the serial port at the old
 696                  * port/type/irq combination.
 697                  */
 698                 uart_shutdown(state);
 699         }
 700
 701         if (change_port) {
 702                 unsigned long old_iobase, old_mapbase;
 703                 unsigned int old_type, old_iotype, old_hub6, old_shift;
 704
 705                 old_iobase = port->iobase;
 706                 old_mapbase = port->mapbase;
 707                 old_type = port->type;
 708                 old_hub6 = port->hub6;
 709                 old_iotype = port->iotype;
 710                 old_shift = port->regshift;
 711
 712                 /*
 713                  * Free and release old regions
 714                  */
 715                 if (old_type != PORT_UNKNOWN)
 716                         port->ops->release_port(port);
 717
 718                 port->iobase = new_port;
 719                 port->type = new_serial.type;
 720                 port->hub6 = new_serial.hub6;
 721                 port->iotype = new_serial.io_type;
 722                 port->regshift = new_serial.iomem_reg_shift;
 723                 port->mapbase = (unsigned long)new_serial.iomem_base;
 724
 725                 /*
 726                  * Claim and map the new regions
 727                  */
 728                 if (port->type != PORT_UNKNOWN) {
 729                         retval = port->ops->request_port(port);
 730                 } else {
 731                         /* Always success - Jean II */
 732                         retval = 0;
 733                 }
 734
 735                 /*
 736                  * If we fail to request resources for the
 737                  * new port, try to restore the old settings.
 738                  */
 739                 if (retval && old_type != PORT_UNKNOWN) {
 740                         port->iobase = old_iobase;
 741                         port->type = old_type;
 742                         port->hub6 = old_hub6;
 743                         port->iotype = old_iotype;
 744                         port->regshift = old_shift;
 745                         port->mapbase = old_mapbase;
 746                         retval = port->ops->request_port(port);
 747                         /*
 748                          * If we failed to restore the old settings,
 749                          * we fail like this.
 750                          */
 751                         if (retval)
 752                                 port->type = PORT_UNKNOWN;
 753
 754                         /*
 755                          * We failed anyway.
 756                          */
 757                         retval = -EBUSY;
 758                 }
 759         }
 760
 761         port->irq              = new_serial.irq;
 762         port->uartclk          = new_serial.baud_base * 16;
 763         port->flags            = (port->flags & ~UPF_CHANGE_MASK) |
 764                                  (new_serial.flags & UPF_CHANGE_MASK);
 765         port->custom_divisor   = new_serial.custom_divisor;
 766         state->close_delay     = close_delay;
 767         state->closing_wait    = closing_wait;
 768         port->fifosize         = new_serial.xmit_fifo_size;
 769         if (state->info->tty)
 770                 state->info->tty->low_latency =
 771                         (port->flags & UPF_LOW_LATENCY) ? 1 : 0;
 772
 773  check_and_exit:
 774         retval = 0;
 775         if (port->type == PORT_UNKNOWN)
 776                 goto exit;
 777         if (state->info->flags & UIF_INITIALIZED) {
 778                 if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||
 779                     old_custom_divisor != port->custom_divisor) {
 780                         /*
 781                          * If they're setting up a custom divisor or speed,
 782                          * instead of clearing it, then bitch about it. No
 783                          * need to rate-limit; it's CAP_SYS_ADMIN only.
 784                          */
 785                         if (port->flags & UPF_SPD_MASK) {
 786                                 char buf[64];
 787                                 printk(KERN_NOTICE
 788                                        "%s sets custom speed on %s. This "
 789                                        "is deprecated.\n", current->comm,
 790                                        tty_name(state->info->tty, buf));
 791                         }
 792                         uart_change_speed(state, NULL);
 793                 }
 794         } else
 795                 retval = uart_startup(state, 1);
 796  exit:
 797         up(&state->sem);
 798         return retval;
 799 }
 800
 801
 802 /*
 803  * uart_get_lsr_info - get line status register info.
 804  * Note: uart_ioctl protects us against hangups.
 805  */
 806 static int uart_get_lsr_info(struct uart_state *state,
 807                              unsigned int __user *value)
 808 {
 809         struct uart_port *port = state->port;
 810         unsigned int result;
 811
 812         result = port->ops->tx_empty(port);
 813
 814         /*
 815          * If we're about to load something into the transmit
 816          * register, we'll pretend the transmitter isn't empty to
 817          * avoid a race condition (depending on when the transmit
 818          * interrupt happens).
 819          */
 820         if (port->x_char ||
 821             ((uart_circ_chars_pending(&state->info->xmit) > 0) &&
 822              !state->info->tty->stopped && !state->info->tty->hw_stopped))
 823                 result &= ~TIOCSER_TEMT;
 824
 825         return put_user(result, value);
 826 }
 827
 828 static int uart_tiocmget(struct tty_struct *tty, struct file *file)
 829 {
 830         struct uart_state *state = tty->driver_data;
 831         struct uart_port *port = state->port;
 832         int result = -EIO;
 833
 834         down(&state->sem);
 835         if ((!file || !tty_hung_up_p(file)) &&
 836             !(tty->flags & (1 << TTY_IO_ERROR))) {
 837                 result = port->mctrl;
 838
 839                 spin_lock_irq(&port->lock);
 840                 result |= port->ops->get_mctrl(port);
 841                 spin_unlock_irq(&port->lock);
 842         }
 843         up(&state->sem);
 844
 845         return result;
 846 }
 847
 848 static int
 849 uart_tiocmset(struct tty_struct *tty, struct file *file,
 850               unsigned int set, unsigned int clear)
 851 {
 852         struct uart_state *state = tty->driver_data;
 853         struct uart_port *port = state->port;
 854         int ret = -EIO;
 855
 856         down(&state->sem);
 857         if ((!file || !tty_hung_up_p(file)) &&
 858             !(tty->flags & (1 << TTY_IO_ERROR))) {
 859                 uart_update_mctrl(port, set, clear);
 860                 ret = 0;
 861         }
 862         up(&state->sem);
 863         return ret;
 864 }
 865
 866 static void uart_break_ctl(struct tty_struct *tty, int break_state)
 867 {
 868         struct uart_state *state = tty->driver_data;
 869         struct uart_port *port = state->port;
 870
 871         BUG_ON(!kernel_locked());
 872
 873         down(&state->sem);
 874
 875         if (port->type != PORT_UNKNOWN)
 876                 port->ops->break_ctl(port, break_state);
 877
 878         up(&state->sem);
 879 }
 880
 881 static int uart_do_autoconfig(struct uart_state *state)
 882 {
 883         struct uart_port *port = state->port;
 884         int flags, ret;
 885
 886         if (!capable(CAP_SYS_ADMIN))
 887                 return -EPERM;
 888
 889         /*
 890          * Take the per-port semaphore.  This prevents count from
 891          * changing, and hence any extra opens of the port while
 892          * we're auto-configuring.
 893          */
 894         if (down_interruptible(&state->sem))
 895                 return -ERESTARTSYS;
 896
 897         ret = -EBUSY;
 898         if (uart_users(state) == 1) {
 899                 uart_shutdown(state);
 900
 901                 /*
 902                  * If we already have a port type configured,
 903                  * we must release its resources.
 904                  */
 905                 if (port->type != PORT_UNKNOWN)
 906                         port->ops->release_port(port);
 907
 908                 flags = UART_CONFIG_TYPE;
 909                 if (port->flags & UPF_AUTO_IRQ)
 910                         flags |= UART_CONFIG_IRQ;
 911
 912                 /*
 913                  * This will claim the ports resources if
 914                  * a port is found.
 915                  */
 916                 port->ops->config_port(port, flags);
 917
 918                 ret = uart_startup(state, 1);
 919         }
 920         up(&state->sem);
 921         return ret;
 922 }
 923
 924 /*
 925  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
 926  * - mask passed in arg for lines of interest
 927  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
 928  * Caller should use TIOCGICOUNT to see which one it was
 929  */
 930 static int
 931 uart_wait_modem_status(struct uart_state *state, unsigned long arg)
 932 {
 933         struct uart_port *port = state->port;
 934         DECLARE_WAITQUEUE(wait, current);
 935         struct uart_icount cprev, cnow;
 936         int ret;
 937
 938         /*
 939          * note the counters on entry
 940          */
 941         spin_lock_irq(&port->lock);
 942         memcpy(&cprev, &port->icount, sizeof(struct uart_icount));
 943
 944         /*
 945          * Force modem status interrupts on
 946          */
 947         port->ops->enable_ms(port);
 948         spin_unlock_irq(&port->lock);
 949
 950         add_wait_queue(&state->info->delta_msr_wait, &wait);
 951         for (;;) {
 952                 spin_lock_irq(&port->lock);
 953                 memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
 954                 spin_unlock_irq(&port->lock);
 955
 956                 set_current_state(TASK_INTERRUPTIBLE);
 957
 958                 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
 959                     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
 960                     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
 961                     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
 962                         ret = 0;
 963                         break;
 964                 }
 965
 966                 schedule();
 967
 968                 /* see if a signal did it */
 969                 if (signal_pending(current)) {
 970                         ret = -ERESTARTSYS;
 971                         break;
 972                 }
 973
 974                 cprev = cnow;
 975         }
 976
 977         current->state = TASK_RUNNING;
 978         remove_wait_queue(&state->info->delta_msr_wait, &wait);
 979
 980         return ret;
 981 }
 982
 983 /*
 984  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
 985  * Return: write counters to the user passed counter struct
 986  * NB: both 1->0 and 0->1 transitions are counted except for
 987  *     RI where only 0->1 is counted.
 988  */
 989 static int uart_get_count(struct uart_state *state,
 990                           struct serial_icounter_struct __user *icnt)
 991 {
 992         struct serial_icounter_struct icount;
 993         struct uart_icount cnow;
 994         struct uart_port *port = state->port;
 995
 996         spin_lock_irq(&port->lock);
 997         memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
 998         spin_unlock_irq(&port->lock);
 999
1000         icount.cts         = cnow.cts;
1001         icount.dsr         = cnow.dsr;
1002         icount.rng         = cnow.rng;
1003         icount.dcd         = cnow.dcd;
1004         icount.rx          = cnow.rx;
1005         icount.tx          = cnow.tx;
1006         icount.frame       = cnow.frame;
1007         icount.overrun     = cnow.overrun;
1008         icount.parity      = cnow.parity;
1009         icount.brk         = cnow.brk;
1010         icount.buf_overrun = cnow.buf_overrun;
1011
1012         return copy_to_user(icnt, &icount, sizeof(icount)) ? -EFAULT : 0;
1013 }
1014
1015 /*
1016  * Called via sys_ioctl under the BKL.  We can use spin_lock_irq() here.
1017  */
1018 static int
1019 uart_ioctl(struct tty_struct *tty, struct file *filp, unsigned int cmd,
1020            unsigned long arg)
1021 {
1022         struct uart_state *state = tty->driver_data;
1023         void __user *uarg = (void __user *)arg;
1024         int ret = -ENOIOCTLCMD;
1025
1026         BUG_ON(!kernel_locked());
1027
1028         /*
1029          * These ioctls don't rely on the hardware to be present.
1030          */
1031         switch (cmd) {
1032         case TIOCGSERIAL:
1033                 ret = uart_get_info(state, uarg);
1034                 break;
1035
1036         case TIOCSSERIAL:
1037                 ret = uart_set_info(state, uarg);
1038                 break;
1039
1040         case TIOCSERCONFIG:
1041                 ret = uart_do_autoconfig(state);
1042                 break;
1043
1044         case TIOCSERGWILD: /* obsolete */
1045         case TIOCSERSWILD: /* obsolete */
1046                 ret = 0;
1047                 break;
1048         }
1049
1050         if (ret != -ENOIOCTLCMD)
1051                 goto out;
1052
1053         if (tty->flags & (1 << TTY_IO_ERROR)) {
1054                 ret = -EIO;
1055                 goto out;
1056         }
1057
1058         /*
1059          * The following should only be used when hardware is present.
1060          */
1061         switch (cmd) {
1062         case TIOCMIWAIT:
1063                 ret = uart_wait_modem_status(state, arg);
1064                 break;
1065
1066         case TIOCGICOUNT:
1067                 ret = uart_get_count(state, uarg);
1068                 break;
1069         }
1070
1071         if (ret != -ENOIOCTLCMD)
1072                 goto out;
1073
1074         down(&state->sem);
1075
1076         if (tty_hung_up_p(filp)) {
1077                 ret = -EIO;
1078                 goto out_up;
1079         }
1080
1081         /*
1082          * All these rely on hardware being present and need to be
1083          * protected against the tty being hung up.
1084          */
1085         switch (cmd) {
1086         case TIOCSERGETLSR: /* Get line status register */
1087                 ret = uart_get_lsr_info(state, uarg);
1088                 break;
1089
1090         default: {
1091                 struct uart_port *port = state->port;
1092                 if (port->ops->ioctl)
1093                         ret = port->ops->ioctl(port, cmd, arg);
1094                 break;
1095         }
1096         }
1097  out_up:
1098         up(&state->sem);
1099  out:
1100         return ret;
1101 }
1102
1103 static void uart_set_termios(struct tty_struct *tty, struct termios *old_termios)
1104 {
1105         struct uart_state *state = tty->driver_data;
1106         unsigned long flags;
1107         unsigned int cflag = tty->termios->c_cflag;
1108
1109         BUG_ON(!kernel_locked());
1110
1111         /*
1112          * These are the bits that are used to setup various
1113          * flags in the low level driver.
1114          */
1115 #define RELEVANT_IFLAG(iflag)   ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
1116
1117         if ((cflag ^ old_termios->c_cflag) == 0 &&
1118             RELEVANT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
1119                 return;
1120
1121         uart_change_speed(state, old_termios);
1122
1123         /* Handle transition to B0 status */
1124         if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1125                 uart_clear_mctrl(state->port, TIOCM_RTS | TIOCM_DTR);
1126
1127         /* Handle transition away from B0 status */
1128         if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1129                 unsigned int mask = TIOCM_DTR;
1130                 if (!(cflag & CRTSCTS) ||
1131                     !test_bit(TTY_THROTTLED, &tty->flags))
1132                         mask |= TIOCM_RTS;
1133                 uart_set_mctrl(state->port, mask);
1134         }
1135
1136         /* Handle turning off CRTSCTS */
1137         if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
1138                 spin_lock_irqsave(&state->port->lock, flags);
1139                 tty->hw_stopped = 0;
1140                 __uart_start(tty);
1141                 spin_unlock_irqrestore(&state->port->lock, flags);
1142         }
1143
1144         /* Handle turning on CRTSCTS */
1145         if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
1146                 spin_lock_irqsave(&state->port->lock, flags);
1147                 if (!(state->port->ops->get_mctrl(state->port) & TIOCM_CTS)) {
1148                         tty->hw_stopped = 1;
1149                         state->port->ops->stop_tx(state->port, 0);
1150                 }
1151                 spin_unlock_irqrestore(&state->port->lock, flags);
1152         }
1153
1154 #if 0
1155         /*
1156          * No need to wake up processes in open wait, since they
1157          * sample the CLOCAL flag once, and don't recheck it.
1158          * XXX  It's not clear whether the current behavior is correct
1159          * or not.  Hence, this may change.....
1160          */
1161         if (!(old_termios->c_cflag & CLOCAL) &&
1162             (tty->termios->c_cflag & CLOCAL))
1163                 wake_up_interruptible(&state->info->open_wait);
1164 #endif
1165 }
1166
1167 /*
1168  * In 2.4.5, calls to this will be serialized via the BKL in
1169  *  linux/drivers/char/tty_io.c:tty_release()
1170  *  linux/drivers/char/tty_io.c:do_tty_handup()
1171  */
1172 static void uart_close(struct tty_struct *tty, struct file *filp)
1173 {
1174         struct uart_state *state = tty->driver_data;
1175         struct uart_port *port;
1176
1177         BUG_ON(!kernel_locked());
1178
1179         if (!state || !state->port)
1180                 return;
1181
1182         port = state->port;
1183
1184         DPRINTK("uart_close(%d) called\n", port->line);
1185
1186         down(&state->sem);
1187
1188         if (tty_hung_up_p(filp))
1189                 goto done;
1190
1191         if ((tty->count == 1) && (state->count != 1)) {
1192                 /*
1193                  * Uh, oh.  tty->count is 1, which means that the tty
1194                  * structure will be freed.  state->count should always
1195                  * be one in these conditions.  If it's greater than
1196                  * one, we've got real problems, since it means the
1197                  * serial port won't be shutdown.
1198                  */
1199                 printk(KERN_ERR "uart_close: bad serial port count; tty->count is 1, "
1200                        "state->count is %d\n", state->count);
1201                 state->count = 1;
1202         }
1203         if (--state->count < 0) {
1204                 printk(KERN_ERR "uart_close: bad serial port count for %s: %d\n",
1205                        tty->name, state->count);
1206                 state->count = 0;
1207         }
1208         if (state->count)
1209                 goto done;
1210
1211         /*
1212          * Now we wait for the transmit buffer to clear; and we notify
1213          * the line discipline to only process XON/XOFF characters by
1214          * setting tty->closing.
1215          */
1216         tty->closing = 1;
1217
1218         if (state->closing_wait != USF_CLOSING_WAIT_NONE)
1219                 tty_wait_until_sent(tty, msecs_to_jiffies(state->closing_wait));
1220
1221         /*
1222          * At this point, we stop accepting input.  To do this, we
1223          * disable the receive line status interrupts.
1224          */
1225         if (state->info->flags & UIF_INITIALIZED) {
1226                 unsigned long flags;
1227                 spin_lock_irqsave(&port->lock, flags);
1228                 port->ops->stop_rx(port);
1229                 spin_unlock_irqrestore(&port->lock, flags);
1230                 /*
1231                  * Before we drop DTR, make sure the UART transmitter
1232                  * has completely drained; this is especially
1233                  * important if there is a transmit FIFO!
1234                  */
1235                 uart_wait_until_sent(tty, port->timeout);
1236         }
1237
1238         uart_shutdown(state);
1239         uart_flush_buffer(tty);
1240
1241         tty_ldisc_flush(tty);
1242
1243         tty->closing = 0;
1244         state->info->tty = NULL;
1245
1246         if (state->info->blocked_open) {
1247                 if (state->close_delay)
1248                         msleep_interruptible(state->close_delay);
1249         } else if (!uart_console(port)) {
1250                 uart_change_pm(state, 3);
1251         }
1252
1253         /*
1254          * Wake up anyone trying to open this port.
1255          */
1256         state->info->flags &= ~UIF_NORMAL_ACTIVE;
1257         wake_up_interruptible(&state->info->open_wait);
1258
1259  done:
1260         up(&state->sem);
1261 }
1262
1263 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1264 {
1265         struct uart_state *state = tty->driver_data;
1266         struct uart_port *port = state->port;
1267         unsigned long char_time, expire;
1268
1269         BUG_ON(!kernel_locked());
1270
1271         if (port->type == PORT_UNKNOWN || port->fifosize == 0)
1272                 return;
1273
1274         /*
1275          * Set the check interval to be 1/5 of the estimated time to
1276          * send a single character, and make it at least 1.  The check
1277          * interval should also be less than the timeout.
1278          *
1279          * Note: we have to use pretty tight timings here to satisfy
1280          * the NIST-PCTS.
1281          */
1282         char_time = (port->timeout - HZ/50) / port->fifosize;
1283         char_time = char_time / 5;
1284         if (char_time == 0)
1285                 char_time = 1;
1286         if (timeout && timeout < char_time)
1287                 char_time = timeout;
1288
1289         /*
1290          * If the transmitter hasn't cleared in twice the approximate
1291          * amount of time to send the entire FIFO, it probably won't
1292          * ever clear.  This assumes the UART isn't doing flow
1293          * control, which is currently the case.  Hence, if it ever
1294          * takes longer than port->timeout, this is probably due to a
1295          * UART bug of some kind.  So, we clamp the timeout parameter at
1296          * 2*port->timeout.
1297          */
1298         if (timeout == 0 || timeout > 2 * port->timeout)
1299                 timeout = 2 * port->timeout;
1300
1301         expire = jiffies + timeout;
1302
1303         DPRINTK("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1304                 port->line, jiffies, expire);
1305
1306         /*
1307          * Check whether the transmitter is empty every 'char_time'.
1308          * 'timeout' / 'expire' give us the maximum amount of time
1309          * we wait.
1310          */
1311         while (!port->ops->tx_empty(port)) {
1312                 msleep_interruptible(jiffies_to_msecs(char_time));
1313                 if (signal_pending(current))
1314                         break;
1315                 if (time_after(jiffies, expire))
1316                         break;
1317         }
1318         set_current_state(TASK_RUNNING); /* might not be needed */
1319 }
1320
1321 /*
1322  * This is called with the BKL held in
1323  *  linux/drivers/char/tty_io.c:do_tty_hangup()
1324  * We're called from the eventd thread, so we can sleep for
1325  * a _short_ time only.
1326  */
1327 static void uart_hangup(struct tty_struct *tty)
1328 {
1329         struct uart_state *state = tty->driver_data;
1330
1331         BUG_ON(!kernel_locked());
1332         DPRINTK("uart_hangup(%d)\n", state->port->line);
1333
1334         down(&state->sem);
1335         if (state->info && state->info->flags & UIF_NORMAL_ACTIVE) {
1336                 uart_flush_buffer(tty);
1337                 uart_shutdown(state);
1338                 state->count = 0;
1339                 state->info->flags &= ~UIF_NORMAL_ACTIVE;
1340                 state->info->tty = NULL;
1341                 wake_up_interruptible(&state->info->open_wait);
1342                 wake_up_interruptible(&state->info->delta_msr_wait);
1343         }
1344         up(&state->sem);
1345 }
1346
1347 /*
1348  * Copy across the serial console cflag setting into the termios settings
1349  * for the initial open of the port.  This allows continuity between the
1350  * kernel settings, and the settings init adopts when it opens the port
1351  * for the first time.
1352  */
1353 static void uart_update_termios(struct uart_state *state)
1354 {
1355         struct tty_struct *tty = state->info->tty;
1356         struct uart_port *port = state->port;
1357
1358         if (uart_console(port) && port->cons->cflag) {
1359                 tty->termios->c_cflag = port->cons->cflag;
1360                 port->cons->cflag = 0;
1361         }
1362
1363         /*
1364          * If the device failed to grab its irq resources,
1365          * or some other error occurred, don't try to talk
1366          * to the port hardware.
1367          */
1368         if (!(tty->flags & (1 << TTY_IO_ERROR))) {
1369                 /*
1370                  * Make termios settings take effect.
1371                  */
1372                 uart_change_speed(state, NULL);
1373
1374                 /*
1375                  * And finally enable the RTS and DTR signals.
1376                  */
1377                 if (tty->termios->c_cflag & CBAUD)
1378                         uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
1379         }
1380 }
1381
1382 /*
1383  * Block the open until the port is ready.  We must be called with
1384  * the per-port semaphore held.
1385  */
1386 static int
1387 uart_block_til_ready(struct file *filp, struct uart_state *state)
1388 {
1389         DECLARE_WAITQUEUE(wait, current);
1390         struct uart_info *info = state->info;
1391         struct uart_port *port = state->port;
1392         unsigned int mctrl;
1393
1394         info->blocked_open++;
1395         state->count--;
1396
1397         add_wait_queue(&info->open_wait, &wait);
1398         while (1) {
1399                 set_current_state(TASK_INTERRUPTIBLE);
1400
1401                 /*
1402                  * If we have been hung up, tell userspace/restart open.
1403                  */
1404                 if (tty_hung_up_p(filp) || info->tty == NULL)
1405                         break;
1406
1407                 /*
1408                  * If the port has been closed, tell userspace/restart open.
1409                  */
1410                 if (!(info->flags & UIF_INITIALIZED))
1411                         break;
1412
1413                 /*
1414                  * If non-blocking mode is set, or CLOCAL mode is set,
1415                  * we don't want to wait for the modem status lines to
1416                  * indicate that the port is ready.
1417                  *
1418                  * Also, if the port is not enabled/configured, we want
1419                  * to allow the open to succeed here.  Note that we will
1420                  * have set TTY_IO_ERROR for a non-existant port.
1421                  */
1422                 if ((filp->f_flags & O_NONBLOCK) ||
1423                     (info->tty->termios->c_cflag & CLOCAL) ||
1424                     (info->tty->flags & (1 << TTY_IO_ERROR))) {
1425                         break;
1426                 }
1427
1428                 /*
1429                  * Set DTR to allow modem to know we're waiting.  Do
1430                  * not set RTS here - we want to make sure we catch
1431                  * the data from the modem.
1432                  */
1433                 if (info->tty->termios->c_cflag & CBAUD)
1434                         uart_set_mctrl(port, TIOCM_DTR);
1435
1436                 /*
1437                  * and wait for the carrier to indicate that the
1438                  * modem is ready for us.
1439                  */
1440                 spin_lock_irq(&port->lock);
1441                 mctrl = port->ops->get_mctrl(port);
1442                 spin_unlock_irq(&port->lock);
1443                 if (mctrl & TIOCM_CAR)
1444                         break;
1445
1446                 up(&state->sem);
1447                 schedule();
1448                 down(&state->sem);
1449
1450                 if (signal_pending(current))
1451                         break;
1452         }
1453         set_current_state(TASK_RUNNING);
1454         remove_wait_queue(&info->open_wait, &wait);
1455
1456         state->count++;
1457         info->blocked_open--;
1458
1459         if (signal_pending(current))
1460                 return -ERESTARTSYS;
1461
1462         if (!info->tty || tty_hung_up_p(filp))
1463                 return -EAGAIN;
1464
1465         return 0;
1466 }
1467
1468 static struct uart_state *uart_get(struct uart_driver *drv, int line)
1469 {
1470         struct uart_state *state;
1471
1472         down(&port_sem);
1473         state = drv->state + line;
1474         if (down_interruptible(&state->sem)) {
1475                 state = ERR_PTR(-ERESTARTSYS);
1476                 goto out;
1477         }
1478
1479         state->count++;
1480         if (!state->port) {
1481                 state->count--;
1482                 up(&state->sem);
1483                 state = ERR_PTR(-ENXIO);
1484                 goto out;
1485         }
1486
1487         if (!state->info) {
1488                 state->info = kmalloc(sizeof(struct uart_info), GFP_KERNEL);
1489                 if (state->info) {
1490                         memset(state->info, 0, sizeof(struct uart_info));
1491                         init_waitqueue_head(&state->info->open_wait);
1492                         init_waitqueue_head(&state->info->delta_msr_wait);
1493
1494                         /*
1495                          * Link the info into the other structures.
1496                          */
1497                         state->port->info = state->info;
1498
1499                         tasklet_init(&state->info->tlet, uart_tasklet_action,
1500                                      (unsigned long)state);
1501                 } else {
1502                         state->count--;
1503                         up(&state->sem);
1504                         state = ERR_PTR(-ENOMEM);
1505                 }
1506         }
1507
1508  out:
1509         up(&port_sem);
1510         return state;
1511 }
1512
1513 /*
1514  * In 2.4.5, calls to uart_open are serialised by the BKL in
1515  *   linux/fs/devices.c:chrdev_open()
1516  * Note that if this fails, then uart_close() _will_ be called.
1517  *
1518  * In time, we want to scrap the "opening nonpresent ports"
1519  * behaviour and implement an alternative way for setserial
1520  * to set base addresses/ports/types.  This will allow us to
1521  * get rid of a certain amount of extra tests.
1522  */
1523 static int uart_open(struct tty_struct *tty, struct file *filp)
1524 {
1525         struct uart_driver *drv = (struct uart_driver *)tty->driver->driver_state;
1526         struct uart_state *state;
1527         int retval, line = tty->index;
1528
1529         BUG_ON(!kernel_locked());
1530         DPRINTK("uart_open(%d) called\n", line);
1531
1532         /*
1533          * tty->driver->num won't change, so we won't fail here with
1534          * tty->driver_data set to something non-NULL (and therefore
1535          * we won't get caught by uart_close()).
1536          */
1537         retval = -ENODEV;
1538         if (line >= tty->driver->num)
1539                 goto fail;
1540
1541         /*
1542          * We take the semaphore inside uart_get to guarantee that we won't
1543          * be re-entered while allocating the info structure, or while we
1544          * request any IRQs that the driver may need.  This also has the nice
1545          * side-effect that it delays the action of uart_hangup, so we can
1546          * guarantee that info->tty will always contain something reasonable.
1547          */
1548         state = uart_get(drv, line);
1549         if (IS_ERR(state)) {
1550                 retval = PTR_ERR(state);
1551                 goto fail;
1552         }
1553
1554         /*
1555          * Once we set tty->driver_data here, we are guaranteed that
1556          * uart_close() will decrement the driver module use count.
1557          * Any failures from here onwards should not touch the count.
1558          */
1559         tty->driver_data = state;
1560         tty->low_latency = (state->port->flags & UPF_LOW_LATENCY) ? 1 : 0;
1561         tty->alt_speed = 0;
1562         state->info->tty = tty;
1563
1564         /*
1565          * If the port is in the middle of closing, bail out now.
1566          */
1567         if (tty_hung_up_p(filp)) {
1568                 retval = -EAGAIN;
1569                 state->count--;
1570                 up(&state->sem);
1571                 goto fail;
1572         }
1573
1574         /*
1575          * Make sure the device is in D0 state.
1576          */
1577         if (state->count == 1)
1578                 uart_change_pm(state, 0);
1579
1580         /*
1581          * Start up the serial port.
1582          */
1583         retval = uart_startup(state, 0);
1584
1585         /*
1586          * If we succeeded, wait until the port is ready.
1587          */
1588         if (retval == 0)
1589                 retval = uart_block_til_ready(filp, state);
1590         up(&state->sem);
1591
1592         /*
1593          * If this is the first open to succeed, adjust things to suit.
1594          */
1595         if (retval == 0 && !(state->info->flags & UIF_NORMAL_ACTIVE)) {
1596                 state->info->flags |= UIF_NORMAL_ACTIVE;
1597
1598                 uart_update_termios(state);
1599         }
1600
1601  fail:
1602         return retval;
1603 }
1604
1605 static const char *uart_type(struct uart_port *port)
1606 {
1607         const char *str = NULL;
1608
1609         if (port->ops->type)
1610                 str = port->ops->type(port);
1611
1612         if (!str)
1613                 str = "unknown";
1614
1615         return str;
1616 }
1617
1618 #ifdef CONFIG_PROC_FS
1619
1620 static int uart_line_info(char *buf, struct uart_driver *drv, int i)
1621 {
1622         struct uart_state *state = drv->state + i;
1623         struct uart_port *port = state->port;
1624         char stat_buf[32];
1625         unsigned int status;
1626         int ret;
1627
1628         if (!port)
1629                 return 0;
1630
1631         ret = sprintf(buf, "%d: uart:%s %s%08lX irq:%d",
1632                         port->line, uart_type(port),
1633                         port->iotype == UPIO_MEM ? "mmio:0x" : "port:",
1634                         port->iotype == UPIO_MEM ? port->mapbase :
1635                                                 (unsigned long) port->iobase,
1636                         port->irq);
1637
1638         if (port->type == PORT_UNKNOWN) {
1639                 strcat(buf, "\n");
1640                 return ret + 1;
1641         }
1642
1643         if(capable(CAP_SYS_ADMIN))
1644         {
1645                 spin_lock_irq(&port->lock);
1646                 status = port->ops->get_mctrl(port);
1647                 spin_unlock_irq(&port->lock);
1648
1649                 ret += sprintf(buf + ret, " tx:%d rx:%d",
1650                                 port->icount.tx, port->icount.rx);
1651                 if (port->icount.frame)
1652                         ret += sprintf(buf + ret, " fe:%d",
1653                                 port->icount.frame);
1654                 if (port->icount.parity)
1655                         ret += sprintf(buf + ret, " pe:%d",
1656                                 port->icount.parity);
1657                 if (port->icount.brk)
1658                         ret += sprintf(buf + ret, " brk:%d",
1659                                 port->icount.brk);
1660                 if (port->icount.overrun)
1661                         ret += sprintf(buf + ret, " oe:%d",
1662                                 port->icount.overrun);
1663
1664 #define INFOBIT(bit,str) \
1665         if (port->mctrl & (bit)) \
1666                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1667                         strlen(stat_buf) - 2)
1668 #define STATBIT(bit,str) \
1669         if (status & (bit)) \
1670                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1671                        strlen(stat_buf) - 2)
1672
1673                 stat_buf[0] = '\0';
1674                 stat_buf[1] = '\0';
1675                 INFOBIT(TIOCM_RTS, "|RTS");
1676                 STATBIT(TIOCM_CTS, "|CTS");
1677                 INFOBIT(TIOCM_DTR, "|DTR");
1678                 STATBIT(TIOCM_DSR, "|DSR");
1679                 STATBIT(TIOCM_CAR, "|CD");
1680                 STATBIT(TIOCM_RNG, "|RI");
1681                 if (stat_buf[0])
1682                         stat_buf[0] = ' ';
1683                 strcat(stat_buf, "\n");
1684
1685                 ret += sprintf(buf + ret, stat_buf);
1686         } else {
1687                 strcat(buf, "\n");
1688                 ret++;
1689         }
1690 #undef STATBIT
1691 #undef INFOBIT
1692         return ret;
1693 }
1694
1695 static int uart_read_proc(char *page, char **start, off_t off,
1696                           int count, int *eof, void *data)
1697 {
1698         struct tty_driver *ttydrv = data;
1699         struct uart_driver *drv = ttydrv->driver_state;
1700         int i, len = 0, l;
1701         off_t begin = 0;
1702
1703         len += sprintf(page, "serinfo:1.0 driver%s%s revision:%s\n",
1704                         "", "", "");
1705         for (i = 0; i < drv->nr && len < PAGE_SIZE - 96; i++) {
1706                 l = uart_line_info(page + len, drv, i);
1707                 len += l;
1708                 if (len + begin > off + count)
1709                         goto done;
1710                 if (len + begin < off) {
1711                         begin += len;
1712                         len = 0;
1713                 }
1714         }
1715         *eof = 1;
1716  done:
1717         if (off >= len + begin)
1718                 return 0;
1719         *start = page + (off - begin);
1720         return (count < begin + len - off) ? count : (begin + len - off);
1721 }
1722 #endif
1723
1724 #ifdef CONFIG_SERIAL_CORE_CONSOLE
1725 /*
1726  *      Check whether an invalid uart number has been specified, and
1727  *      if so, search for the first available port that does have
1728  *      console support.
1729  */
1730 struct uart_port * __init
1731 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1732 {
1733         int idx = co->index;
1734
1735         if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1736                                      ports[idx].membase == NULL))
1737                 for (idx = 0; idx < nr; idx++)
1738                         if (ports[idx].iobase != 0 ||
1739                             ports[idx].membase != NULL)
1740                                 break;
1741
1742         co->index = idx;
1743
1744         return ports + idx;
1745 }
1746
1747 /**
1748  *      uart_parse_options - Parse serial port baud/parity/bits/flow contro.
1749  *      @options: pointer to option string
1750  *      @baud: pointer to an 'int' variable for the baud rate.
1751  *      @parity: pointer to an 'int' variable for the parity.
1752  *      @bits: pointer to an 'int' variable for the number of data bits.
1753  *      @flow: pointer to an 'int' variable for the flow control character.
1754  *
1755  *      uart_parse_options decodes a string containing the serial console
1756  *      options.  The format of the string is <baud><parity><bits><flow>,
1757  *      eg: 115200n8r
1758  */
1759 void __init
1760 uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
1761 {
1762         char *s = options;
1763
1764         *baud = simple_strtoul(s, NULL, 10);
1765         while (*s >= '0' && *s <= '9')
1766                 s++;
1767         if (*s)
1768                 *parity = *s++;
1769         if (*s)
1770                 *bits = *s++ - '0';
1771         if (*s)
1772                 *flow = *s;
1773 }
1774
1775 struct baud_rates {
1776         unsigned int rate;
1777         unsigned int cflag;
1778 };
1779
1780 static struct baud_rates baud_rates[] = {
1781         { 921600, B921600 },
1782         { 460800, B460800 },
1783         { 230400, B230400 },
1784         { 115200, B115200 },
1785         {  57600, B57600  },
1786         {  38400, B38400  },
1787         {  19200, B19200  },
1788         {   9600, B9600   },
1789         {   4800, B4800   },
1790         {   2400, B2400   },
1791         {   1200, B1200   },
1792         {      0, B38400  }
1793 };
1794
1795 /**
1796  *      uart_set_options - setup the serial console parameters
1797  *      @port: pointer to the serial ports uart_port structure
1798  *      @co: console pointer
1799  *      @baud: baud rate
1800  *      @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
1801  *      @bits: number of data bits
1802  *      @flow: flow control character - 'r' (rts)
1803  */
1804 int __init
1805 uart_set_options(struct uart_port *port, struct console *co,
1806                  int baud, int parity, int bits, int flow)
1807 {
1808         struct termios termios;
1809         int i;
1810
1811         /*
1812          * Ensure that the serial console lock is initialised
1813          * early.
1814          */
1815         spin_lock_init(&port->lock);
1816
1817         memset(&termios, 0, sizeof(struct termios));
1818
1819         termios.c_cflag = CREAD | HUPCL | CLOCAL;
1820
1821         /*
1822          * Construct a cflag setting.
1823          */
1824         for (i = 0; baud_rates[i].rate; i++)
1825                 if (baud_rates[i].rate <= baud)
1826                         break;
1827
1828         termios.c_cflag |= baud_rates[i].cflag;
1829
1830         if (bits == 7)
1831                 termios.c_cflag |= CS7;
1832         else
1833                 termios.c_cflag |= CS8;
1834
1835         switch (parity) {
1836         case 'o': case 'O':
1837                 termios.c_cflag |= PARODD;
1838                 /*fall through*/
1839         case 'e': case 'E':
1840                 termios.c_cflag |= PARENB;
1841                 break;
1842         }
1843
1844         if (flow == 'r')
1845                 termios.c_cflag |= CRTSCTS;
1846
1847         port->ops->set_termios(port, &termios, NULL);
1848         co->cflag = termios.c_cflag;
1849
1850         return 0;
1851 }
1852 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
1853
1854 static void uart_change_pm(struct uart_state *state, int pm_state)
1855 {
1856         struct uart_port *port = state->port;
1857         if (port->ops->pm)
1858                 port->ops->pm(port, pm_state, state->pm_state);
1859         state->pm_state = pm_state;
1860 }
1861
1862 int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
1863 {
1864         struct uart_state *state = drv->state + port->line;
1865
1866         down(&state->sem);
1867
1868         if (state->info && state->info->flags & UIF_INITIALIZED) {
1869                 struct uart_ops *ops = port->ops;
1870
1871                 spin_lock_irq(&port->lock);
1872                 ops->stop_tx(port, 0);
1873                 ops->set_mctrl(port, 0);
1874                 ops->stop_rx(port);
1875                 spin_unlock_irq(&port->lock);
1876
1877                 /*
1878                  * Wait for the transmitter to empty.
1879                  */
1880                 while (!ops->tx_empty(port)) {
1881                         msleep(10);
1882                 }
1883
1884                 ops->shutdown(port);
1885         }
1886
1887         /*
1888          * Disable the console device before suspending.
1889          */
1890         if (uart_console(port))
1891                 console_stop(port->cons);
1892
1893         uart_change_pm(state, 3);
1894
1895         up(&state->sem);
1896
1897         return 0;
1898 }
1899
1900 int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
1901 {
1902         struct uart_state *state = drv->state + port->line;
1903
1904         down(&state->sem);
1905
1906         uart_change_pm(state, 0);
1907
1908         /*
1909          * Re-enable the console device after suspending.
1910          */
1911         if (uart_console(port)) {
1912                 struct termios termios;
1913
1914                 /*
1915                  * First try to use the console cflag setting.
1916                  */
1917                 memset(&termios, 0, sizeof(struct termios));
1918                 termios.c_cflag = port->cons->cflag;
1919
1920                 /*
1921                  * If that's unset, use the tty termios setting.
1922                  */
1923                 if (state->info && state->info->tty && termios.c_cflag == 0)
1924                         termios = *state->info->tty->termios;
1925
1926                 port->ops->set_termios(port, &termios, NULL);
1927                 console_start(port->cons);
1928         }
1929
1930         if (state->info && state->info->flags & UIF_INITIALIZED) {
1931                 struct uart_ops *ops = port->ops;
1932
1933                 ops->set_mctrl(port, 0);
1934                 ops->startup(port);
1935                 uart_change_speed(state, NULL);
1936                 spin_lock_irq(&port->lock);
1937                 ops->set_mctrl(port, port->mctrl);
1938                 ops->start_tx(port, 0);
1939                 spin_unlock_irq(&port->lock);
1940         }
1941
1942         up(&state->sem);
1943
1944         return 0;
1945 }
1946
1947 static inline void
1948 uart_report_port(struct uart_driver *drv, struct uart_port *port)
1949 {
1950         printk("%s%d", drv->dev_name, port->line);
1951         printk(" at ");
1952         switch (port->iotype) {
1953         case UPIO_PORT:
1954                 printk("I/O 0x%x", port->iobase);
1955                 break;
1956         case UPIO_HUB6:
1957                 printk("I/O 0x%x offset 0x%x", port->iobase, port->hub6);
1958                 break;
1959         case UPIO_MEM:
1960         case UPIO_MEM32:
1961                 printk("MMIO 0x%lx", port->mapbase);
1962                 break;
1963         }
1964         printk(" (irq = %d) is a %s\n", port->irq, uart_type(port));
1965 }
1966
1967 static void
1968 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
1969                     struct uart_port *port)
1970 {
1971         unsigned int flags;
1972
1973         /*
1974          * If there isn't a port here, don't do anything further.
1975          */
1976         if (!port->iobase && !port->mapbase && !port->membase)
1977                 return;
1978
1979         /*
1980          * Now do the auto configuration stuff.  Note that config_port
1981          * is expected to claim the resources and map the port for us.
1982          */
1983         flags = UART_CONFIG_TYPE;
1984         if (port->flags & UPF_AUTO_IRQ)
1985                 flags |= UART_CONFIG_IRQ;
1986         if (port->flags & UPF_BOOT_AUTOCONF) {
1987                 port->type = PORT_UNKNOWN;
1988                 port->ops->config_port(port, flags);
1989         }
1990
1991         if (port->type != PORT_UNKNOWN) {
1992                 unsigned long flags;
1993
1994                 uart_report_port(drv, port);
1995
1996                 /*
1997                  * Ensure that the modem control lines are de-activated.
1998                  * We probably don't need a spinlock around this, but
1999                  */
2000                 spin_lock_irqsave(&port->lock, flags);
2001                 port->ops->set_mctrl(port, 0);
2002                 spin_unlock_irqrestore(&port->lock, flags);
2003
2004                 /*
2005                  * Power down all ports by default, except the
2006                  * console if we have one.
2007                  */
2008                 if (!uart_console(port))
2009                         uart_change_pm(state, 3);
2010         }
2011 }
2012
2013 /*
2014  * This reverses the effects of uart_configure_port, hanging up the
2015  * port before removal.
2016  */
2017 static void
2018 uart_unconfigure_port(struct uart_driver *drv, struct uart_state *state)
2019 {
2020         struct uart_port *port = state->port;
2021         struct uart_info *info = state->info;
2022
2023         if (info && info->tty)
2024                 tty_vhangup(info->tty);
2025
2026         down(&state->sem);
2027
2028         state->info = NULL;
2029
2030         /*
2031          * Free the port IO and memory resources, if any.
2032          */
2033         if (port->type != PORT_UNKNOWN)
2034                 port->ops->release_port(port);
2035
2036         /*
2037          * Indicate that there isn't a port here anymore.
2038          */
2039         port->type = PORT_UNKNOWN;
2040
2041         /*
2042          * Kill the tasklet, and free resources.
2043          */
2044         if (info) {
2045                 tasklet_kill(&info->tlet);
2046                 kfree(info);
2047         }
2048
2049         up(&state->sem);
2050 }
2051
2052 static struct tty_operations uart_ops = {
2053         .open           = uart_open,
2054         .close          = uart_close,
2055         .write          = uart_write,
2056         .put_char       = uart_put_char,
2057         .flush_chars    = uart_flush_chars,
2058         .write_room     = uart_write_room,
2059         .chars_in_buffer= uart_chars_in_buffer,
2060         .flush_buffer   = uart_flush_buffer,
2061         .ioctl          = uart_ioctl,
2062         .throttle       = uart_throttle,
2063         .unthrottle     = uart_unthrottle,
2064         .send_xchar     = uart_send_xchar,
2065         .set_termios    = uart_set_termios,
2066         .stop           = uart_stop,
2067         .start          = uart_start,
2068         .hangup         = uart_hangup,
2069         .break_ctl      = uart_break_ctl,
2070         .wait_until_sent= uart_wait_until_sent,
2071 #ifdef CONFIG_PROC_FS
2072         .read_proc      = uart_read_proc,
2073 #endif
2074         .tiocmget       = uart_tiocmget,
2075         .tiocmset       = uart_tiocmset,
2076 };
2077
2078 /**
2079  *      uart_register_driver - register a driver with the uart core layer
2080  *      @drv: low level driver structure
2081  *
2082  *      Register a uart driver with the core driver.  We in turn register
2083  *      with the tty layer, and initialise the core driver per-port state.
2084  *
2085  *      We have a proc file in /proc/tty/driver which is named after the
2086  *      normal driver.
2087  *
2088  *      drv->port should be NULL, and the per-port structures should be
2089  *      registered using uart_add_one_port after this call has succeeded.
2090  */
2091 int uart_register_driver(struct uart_driver *drv)
2092 {
2093         struct tty_driver *normal = NULL;
2094         int i, retval;
2095
2096         BUG_ON(drv->state);
2097
2098         /*
2099          * Maybe we should be using a slab cache for this, especially if
2100          * we have a large number of ports to handle.
2101          */
2102         drv->state = kmalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
2103         retval = -ENOMEM;
2104         if (!drv->state)
2105                 goto out;
2106
2107         memset(drv->state, 0, sizeof(struct uart_state) * drv->nr);
2108
2109         normal  = alloc_tty_driver(drv->nr);
2110         if (!normal)
2111                 goto out;
2112
2113         drv->tty_driver = normal;
2114
2115         normal->owner           = drv->owner;
2116         normal->driver_name     = drv->driver_name;
2117         normal->devfs_name      = drv->devfs_name;
2118         normal->name            = drv->dev_name;
2119         normal->major           = drv->major;
2120         normal->minor_start     = drv->minor;
2121         normal->type            = TTY_DRIVER_TYPE_SERIAL;
2122         normal->subtype         = SERIAL_TYPE_NORMAL;
2123         normal->init_termios    = tty_std_termios;
2124         normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2125         normal->flags           = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
2126         normal->driver_state    = drv;
2127         tty_set_operations(normal, &uart_ops);
2128
2129         /*
2130          * Initialise the UART state(s).
2131          */
2132         for (i = 0; i < drv->nr; i++) {
2133                 struct uart_state *state = drv->state + i;
2134
2135                 state->close_delay     = 500;   /* .5 seconds */
2136                 state->closing_wait    = 30000; /* 30 seconds */
2137
2138                 init_MUTEX(&state->sem);
2139         }
2140
2141         retval = tty_register_driver(normal);
2142  out:
2143         if (retval < 0) {
2144                 put_tty_driver(normal);
2145                 kfree(drv->state);
2146         }
2147         return retval;
2148 }
2149
2150 /**
2151  *      uart_unregister_driver - remove a driver from the uart core layer
2152  *      @drv: low level driver structure
2153  *
2154  *      Remove all references to a driver from the core driver.  The low
2155  *      level driver must have removed all its ports via the
2156  *      uart_remove_one_port() if it registered them with uart_add_one_port().
2157  *      (ie, drv->port == NULL)
2158  */
2159 void uart_unregister_driver(struct uart_driver *drv)
2160 {
2161         struct tty_driver *p = drv->tty_driver;
2162         tty_unregister_driver(p);
2163         put_tty_driver(p);
2164         kfree(drv->state);
2165         drv->tty_driver = NULL;
2166 }
2167
2168 struct tty_driver *uart_console_device(struct console *co, int *index)
2169 {
2170         struct uart_driver *p = co->data;
2171         *index = co->index;
2172         return p->tty_driver;
2173 }
2174
2175 /**
2176  *      uart_add_one_port - attach a driver-defined port structure
2177  *      @drv: pointer to the uart low level driver structure for this port
2178  *      @port: uart port structure to use for this port.
2179  *
2180  *      This allows the driver to register its own uart_port structure
2181  *      with the core driver.  The main purpose is to allow the low
2182  *      level uart drivers to expand uart_port, rather than having yet
2183  *      more levels of structures.
2184  */
2185 int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
2186 {
2187         struct uart_state *state;
2188         int ret = 0;
2189
2190         BUG_ON(in_interrupt());
2191
2192         if (port->line >= drv->nr)
2193                 return -EINVAL;
2194
2195         state = drv->state + port->line;
2196
2197         down(&port_sem);
2198         if (state->port) {
2199                 ret = -EINVAL;
2200                 goto out;
2201         }
2202
2203         state->port = port;
2204
2205         port->cons = drv->cons;
2206         port->info = state->info;
2207
2208         /*
2209          * If this port is a console, then the spinlock is already
2210          * initialised.
2211          */
2212         if (!uart_console(port))
2213                 spin_lock_init(&port->lock);
2214
2215         uart_configure_port(drv, state, port);
2216
2217         /*
2218          * Register the port whether it's detected or not.  This allows
2219          * setserial to be used to alter this ports parameters.
2220          */
2221         tty_register_device(drv->tty_driver, port->line, port->dev);
2222
2223         /*
2224          * If this driver supports console, and it hasn't been
2225          * successfully registered yet, try to re-register it.
2226          * It may be that the port was not available.
2227          */
2228         if (port->type != PORT_UNKNOWN &&
2229             port->cons && !(port->cons->flags & CON_ENABLED))
2230                 register_console(port->cons);
2231
2232  out:
2233         up(&port_sem);
2234
2235         return ret;
2236 }
2237
2238 /**
2239  *      uart_remove_one_port - detach a driver defined port structure
2240  *      @drv: pointer to the uart low level driver structure for this port
2241  *      @port: uart port structure for this port
2242  *
2243  *      This unhooks (and hangs up) the specified port structure from the
2244  *      core driver.  No further calls will be made to the low-level code
2245  *      for this port.
2246  */
2247 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
2248 {
2249         struct uart_state *state = drv->state + port->line;
2250
2251         BUG_ON(in_interrupt());
2252
2253         if (state->port != port)
2254                 printk(KERN_ALERT "Removing wrong port: %p != %p\n",
2255                         state->port, port);
2256
2257         down(&port_sem);
2258
2259         /*
2260          * Remove the devices from devfs
2261          */
2262         tty_unregister_device(drv->tty_driver, port->line);
2263
2264         uart_unconfigure_port(drv, state);
2265         state->port = NULL;
2266         up(&port_sem);
2267
2268         return 0;
2269 }
2270
2271 /*
2272  *      Are the two ports equivalent?
2273  */
2274 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2275 {
2276         if (port1->iotype != port2->iotype)
2277                 return 0;
2278
2279         switch (port1->iotype) {
2280         case UPIO_PORT:
2281                 return (port1->iobase == port2->iobase);
2282         case UPIO_HUB6:
2283                 return (port1->iobase == port2->iobase) &&
2284                        (port1->hub6   == port2->hub6);
2285         case UPIO_MEM:
2286                 return (port1->membase == port2->membase);
2287         }
2288         return 0;
2289 }
2290 EXPORT_SYMBOL(uart_match_port);
2291
2292 /*
2293  *      Try to find an unused uart_state slot for a port.
2294  */
2295 static struct uart_state *
2296 uart_find_match_or_unused(struct uart_driver *drv, struct uart_port *port)
2297 {
2298         int i;
2299
2300         /*
2301          * First, find a port entry which matches.  Note: if we do
2302          * find a matching entry, and it has a non-zero use count,
2303          * then we can't register the port.
2304          */
2305         for (i = 0; i < drv->nr; i++)
2306                 if (uart_match_port(drv->state[i].port, port))
2307                         return &drv->state[i];
2308
2309         /*
2310          * We didn't find a matching entry, so look for the first
2311          * free entry.  We look for one which hasn't been previously
2312          * used (indicated by zero iobase).
2313          */
2314         for (i = 0; i < drv->nr; i++)
2315                 if (drv->state[i].port->type == PORT_UNKNOWN &&
2316                     drv->state[i].port->iobase == 0 &&
2317                     drv->state[i].count == 0)
2318                         return &drv->state[i];
2319
2320         /*
2321          * That also failed.  Last resort is to find any currently
2322          * entry which doesn't have a real port associated with it.
2323          */
2324         for (i = 0; i < drv->nr; i++)
2325                 if (drv->state[i].port->type == PORT_UNKNOWN &&
2326                     drv->state[i].count == 0)
2327                         return &drv->state[i];
2328
2329         return NULL;
2330 }
2331
2332 /**
2333  *      uart_register_port: register uart settings with a port
2334  *      @drv: pointer to the uart low level driver structure for this port
2335  *      @port: uart port structure describing the port
2336  *
2337  *      Register UART settings with the specified low level driver.  Detect
2338  *      the type of the port if UPF_BOOT_AUTOCONF is set, and detect the
2339  *      IRQ if UPF_AUTO_IRQ is set.
2340  *
2341  *      We try to pick the same port for the same IO base address, so that
2342  *      when a modem is plugged in, unplugged and plugged back in, it gets
2343  *      allocated the same port.
2344  *
2345  *      Returns negative error, or positive line number.
2346  */
2347 int uart_register_port(struct uart_driver *drv, struct uart_port *port)
2348 {
2349         struct uart_state *state;
2350         int ret;
2351
2352         down(&port_sem);
2353
2354         state = uart_find_match_or_unused(drv, port);
2355
2356         if (state) {
2357                 /*
2358                  * Ok, we've found a line that we can use.
2359                  *
2360                  * If we find a port that matches this one, and it appears
2361                  * to be in-use (even if it doesn't have a type) we shouldn't
2362                  * alter it underneath itself - the port may be open and
2363                  * trying to do useful work.
2364                  */
2365                 if (uart_users(state) != 0) {
2366                         ret = -EBUSY;
2367                         goto out;
2368                 }
2369
2370                 /*
2371                  * If the port is already initialised, don't touch it.
2372                  */
2373                 if (state->port->type == PORT_UNKNOWN) {
2374                         state->port->iobase   = port->iobase;
2375                         state->port->membase  = port->membase;
2376                         state->port->irq      = port->irq;
2377                         state->port->uartclk  = port->uartclk;
2378                         state->port->fifosize = port->fifosize;
2379                         state->port->regshift = port->regshift;
2380                         state->port->iotype   = port->iotype;
2381                         state->port->flags    = port->flags;
2382                         state->port->line     = state - drv->state;
2383                         state->port->mapbase  = port->mapbase;
2384
2385                         uart_configure_port(drv, state, state->port);
2386                 }
2387
2388                 ret = state->port->line;
2389         } else
2390                 ret = -ENOSPC;
2391  out:
2392         up(&port_sem);
2393         return ret;
2394 }
2395
2396 /**
2397  *      uart_unregister_port - de-allocate a port
2398  *      @drv: pointer to the uart low level driver structure for this port
2399  *      @line: line index previously returned from uart_register_port()
2400  *
2401  *      Hang up the specified line associated with the low level driver,
2402  *      and mark the port as unused.
2403  */
2404 void uart_unregister_port(struct uart_driver *drv, int line)
2405 {
2406         struct uart_state *state;
2407
2408         if (line < 0 || line >= drv->nr) {
2409                 printk(KERN_ERR "Attempt to unregister ");
2410                 printk("%s%d", drv->dev_name, line);
2411                 printk("\n");
2412                 return;
2413         }
2414
2415         state = drv->state + line;
2416
2417         down(&port_sem);
2418         uart_unconfigure_port(drv, state);
2419         up(&port_sem);
2420 }
2421
2422 EXPORT_SYMBOL(uart_write_wakeup);
2423 EXPORT_SYMBOL(uart_register_driver);
2424 EXPORT_SYMBOL(uart_unregister_driver);
2425 EXPORT_SYMBOL(uart_suspend_port);
2426 EXPORT_SYMBOL(uart_resume_port);
2427 EXPORT_SYMBOL(uart_register_port);
2428 EXPORT_SYMBOL(uart_unregister_port);
2429 EXPORT_SYMBOL(uart_add_one_port);
2430 EXPORT_SYMBOL(uart_remove_one_port);
2431
2432 MODULE_DESCRIPTION("Serial driver core");
2433 MODULE_LICENSE("GPL");