linux/drivers/tty/serial/serial_core.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *  Driver core for serial ports
   4 *
   5 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   6 *
   7 *  Copyright 1999 ARM Limited
   8 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
   9 */
  10#include <linux/module.h>
  11#include <linux/tty.h>
  12#include <linux/tty_flip.h>
  13#include <linux/slab.h>
  14#include <linux/sched/signal.h>
  15#include <linux/init.h>
  16#include <linux/console.h>
  17#include <linux/gpio/consumer.h>
  18#include <linux/of.h>
  19#include <linux/proc_fs.h>
  20#include <linux/seq_file.h>
  21#include <linux/device.h>
  22#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
  23#include <linux/serial_core.h>
  24#include <linux/sysrq.h>
  25#include <linux/delay.h>
  26#include <linux/mutex.h>
  27#include <linux/security.h>
  28
  29#include <linux/irq.h>
  30#include <linux/uaccess.h>
  31
  32/*
  33 * This is used to lock changes in serial line configuration.
  34 */
  35static DEFINE_MUTEX(port_mutex);
  36
  37/*
  38 * lockdep: port->lock is initialized in two places, but we
  39 *          want only one lock-class:
  40 */
  41static struct lock_class_key port_lock_key;
  42
  43#define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
  44
  45static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
  46                                        struct ktermios *old_termios);
  47static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
  48static void uart_change_pm(struct uart_state *state,
  49                           enum uart_pm_state pm_state);
  50
  51static void uart_port_shutdown(struct tty_port *port);
  52
  53static int uart_dcd_enabled(struct uart_port *uport)
  54{
  55        return !!(uport->status & UPSTAT_DCD_ENABLE);
  56}
  57
  58static inline struct uart_port *uart_port_ref(struct uart_state *state)
  59{
  60        if (atomic_add_unless(&state->refcount, 1, 0))
  61                return state->uart_port;
  62        return NULL;
  63}
  64
  65static inline void uart_port_deref(struct uart_port *uport)
  66{
  67        if (atomic_dec_and_test(&uport->state->refcount))
  68                wake_up(&uport->state->remove_wait);
  69}
  70
  71#define uart_port_lock(state, flags)                                    \
  72        ({                                                              \
  73                struct uart_port *__uport = uart_port_ref(state);       \
  74                if (__uport)                                            \
  75                        spin_lock_irqsave(&__uport->lock, flags);       \
  76                __uport;                                                \
  77        })
  78
  79#define uart_port_unlock(uport, flags)                                  \
  80        ({                                                              \
  81                struct uart_port *__uport = uport;                      \
  82                if (__uport) {                                          \
  83                        spin_unlock_irqrestore(&__uport->lock, flags);  \
  84                        uart_port_deref(__uport);                       \
  85                }                                                       \
  86        })
  87
  88static inline struct uart_port *uart_port_check(struct uart_state *state)
  89{
  90        lockdep_assert_held(&state->port.mutex);
  91        return state->uart_port;
  92}
  93
  94/*
  95 * This routine is used by the interrupt handler to schedule processing in
  96 * the software interrupt portion of the driver.
  97 */
  98void uart_write_wakeup(struct uart_port *port)
  99{
 100        struct uart_state *state = port->state;
 101        /*
 102         * This means you called this function _after_ the port was
 103         * closed.  No cookie for you.
 104         */
 105        BUG_ON(!state);
 106        tty_port_tty_wakeup(&state->port);
 107}
 108
 109static void uart_stop(struct tty_struct *tty)
 110{
 111        struct uart_state *state = tty->driver_data;
 112        struct uart_port *port;
 113        unsigned long flags;
 114
 115        port = uart_port_lock(state, flags);
 116        if (port)
 117                port->ops->stop_tx(port);
 118        uart_port_unlock(port, flags);
 119}
 120
 121static void __uart_start(struct tty_struct *tty)
 122{
 123        struct uart_state *state = tty->driver_data;
 124        struct uart_port *port = state->uart_port;
 125
 126        if (port && !uart_tx_stopped(port))
 127                port->ops->start_tx(port);
 128}
 129
 130static void uart_start(struct tty_struct *tty)
 131{
 132        struct uart_state *state = tty->driver_data;
 133        struct uart_port *port;
 134        unsigned long flags;
 135
 136        port = uart_port_lock(state, flags);
 137        __uart_start(tty);
 138        uart_port_unlock(port, flags);
 139}
 140
 141static void
 142uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
 143{
 144        unsigned long flags;
 145        unsigned int old;
 146
 147        spin_lock_irqsave(&port->lock, flags);
 148        old = port->mctrl;
 149        port->mctrl = (old & ~clear) | set;
 150        if (old != port->mctrl)
 151                port->ops->set_mctrl(port, port->mctrl);
 152        spin_unlock_irqrestore(&port->lock, flags);
 153}
 154
 155#define uart_set_mctrl(port, set)       uart_update_mctrl(port, set, 0)
 156#define uart_clear_mctrl(port, clear)   uart_update_mctrl(port, 0, clear)
 157
 158static void uart_port_dtr_rts(struct uart_port *uport, int raise)
 159{
 160        int rs485_on = uport->rs485_config &&
 161                (uport->rs485.flags & SER_RS485_ENABLED);
 162        int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
 163
 164        if (raise) {
 165                if (rs485_on && !RTS_after_send) {
 166                        uart_set_mctrl(uport, TIOCM_DTR);
 167                        uart_clear_mctrl(uport, TIOCM_RTS);
 168                } else {
 169                        uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 170                }
 171        } else {
 172                unsigned int clear = TIOCM_DTR;
 173
 174                clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
 175                uart_clear_mctrl(uport, clear);
 176        }
 177}
 178
 179/*
 180 * Startup the port.  This will be called once per open.  All calls
 181 * will be serialised by the per-port mutex.
 182 */
 183static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 184                int init_hw)
 185{
 186        struct uart_port *uport = uart_port_check(state);
 187        unsigned long page;
 188        unsigned long flags = 0;
 189        int retval = 0;
 190
 191        if (uport->type == PORT_UNKNOWN)
 192                return 1;
 193
 194        /*
 195         * Make sure the device is in D0 state.
 196         */
 197        uart_change_pm(state, UART_PM_STATE_ON);
 198
 199        /*
 200         * Initialise and allocate the transmit and temporary
 201         * buffer.
 202         */
 203        page = get_zeroed_page(GFP_KERNEL);
 204        if (!page)
 205                return -ENOMEM;
 206
 207        uart_port_lock(state, flags);
 208        if (!state->xmit.buf) {
 209                state->xmit.buf = (unsigned char *) page;
 210                uart_circ_clear(&state->xmit);
 211                uart_port_unlock(uport, flags);
 212        } else {
 213                uart_port_unlock(uport, flags);
 214                /*
 215                 * Do not free() the page under the port lock, see
 216                 * uart_shutdown().
 217                 */
 218                free_page(page);
 219        }
 220
 221        retval = uport->ops->startup(uport);
 222        if (retval == 0) {
 223                if (uart_console(uport) && uport->cons->cflag) {
 224                        tty->termios.c_cflag = uport->cons->cflag;
 225                        uport->cons->cflag = 0;
 226                }
 227                /*
 228                 * Initialise the hardware port settings.
 229                 */
 230                uart_change_speed(tty, state, NULL);
 231
 232                /*
 233                 * Setup the RTS and DTR signals once the
 234                 * port is open and ready to respond.
 235                 */
 236                if (init_hw && C_BAUD(tty))
 237                        uart_port_dtr_rts(uport, 1);
 238        }
 239
 240        /*
 241         * This is to allow setserial on this port. People may want to set
 242         * port/irq/type and then reconfigure the port properly if it failed
 243         * now.
 244         */
 245        if (retval && capable(CAP_SYS_ADMIN))
 246                return 1;
 247
 248        return retval;
 249}
 250
 251static int uart_startup(struct tty_struct *tty, struct uart_state *state,
 252                int init_hw)
 253{
 254        struct tty_port *port = &state->port;
 255        int retval;
 256
 257        if (tty_port_initialized(port))
 258                return 0;
 259
 260        retval = uart_port_startup(tty, state, init_hw);
 261        if (retval)
 262                set_bit(TTY_IO_ERROR, &tty->flags);
 263
 264        return retval;
 265}
 266
 267/*
 268 * This routine will shutdown a serial port; interrupts are disabled, and
 269 * DTR is dropped if the hangup on close termio flag is on.  Calls to
 270 * uart_shutdown are serialised by the per-port semaphore.
 271 *
 272 * uport == NULL if uart_port has already been removed
 273 */
 274static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 275{
 276        struct uart_port *uport = uart_port_check(state);
 277        struct tty_port *port = &state->port;
 278        unsigned long flags = 0;
 279        char *xmit_buf = NULL;
 280
 281        /*
 282         * Set the TTY IO error marker
 283         */
 284        if (tty)
 285                set_bit(TTY_IO_ERROR, &tty->flags);
 286
 287        if (tty_port_initialized(port)) {
 288                tty_port_set_initialized(port, 0);
 289
 290                /*
 291                 * Turn off DTR and RTS early.
 292                 */
 293                if (uport && uart_console(uport) && tty)
 294                        uport->cons->cflag = tty->termios.c_cflag;
 295
 296                if (!tty || C_HUPCL(tty))
 297                        uart_port_dtr_rts(uport, 0);
 298
 299                uart_port_shutdown(port);
 300        }
 301
 302        /*
 303         * It's possible for shutdown to be called after suspend if we get
 304         * a DCD drop (hangup) at just the right time.  Clear suspended bit so
 305         * we don't try to resume a port that has been shutdown.
 306         */
 307        tty_port_set_suspended(port, 0);
 308
 309        /*
 310         * Do not free() the transmit buffer page under the port lock since
 311         * this can create various circular locking scenarios. For instance,
 312         * console driver may need to allocate/free a debug object, which
 313         * can endup in printk() recursion.
 314         */
 315        uart_port_lock(state, flags);
 316        xmit_buf = state->xmit.buf;
 317        state->xmit.buf = NULL;
 318        uart_port_unlock(uport, flags);
 319
 320        if (xmit_buf)
 321                free_page((unsigned long)xmit_buf);
 322}
 323
 324/**
 325 *      uart_update_timeout - update per-port FIFO timeout.
 326 *      @port:  uart_port structure describing the port
 327 *      @cflag: termios cflag value
 328 *      @baud:  speed of the port
 329 *
 330 *      Set the port FIFO timeout value.  The @cflag value should
 331 *      reflect the actual hardware settings.
 332 */
 333void
 334uart_update_timeout(struct uart_port *port, unsigned int cflag,
 335                    unsigned int baud)
 336{
 337        unsigned int bits;
 338
 339        /* byte size and parity */
 340        switch (cflag & CSIZE) {
 341        case CS5:
 342                bits = 7;
 343                break;
 344        case CS6:
 345                bits = 8;
 346                break;
 347        case CS7:
 348                bits = 9;
 349                break;
 350        default:
 351                bits = 10;
 352                break; /* CS8 */
 353        }
 354
 355        if (cflag & CSTOPB)
 356                bits++;
 357        if (cflag & PARENB)
 358                bits++;
 359
 360        /*
 361         * The total number of bits to be transmitted in the fifo.
 362         */
 363        bits = bits * port->fifosize;
 364
 365        /*
 366         * Figure the timeout to send the above number of bits.
 367         * Add .02 seconds of slop
 368         */
 369        port->timeout = (HZ * bits) / baud + HZ/50;
 370}
 371
 372EXPORT_SYMBOL(uart_update_timeout);
 373
 374/**
 375 *      uart_get_baud_rate - return baud rate for a particular port
 376 *      @port: uart_port structure describing the port in question.
 377 *      @termios: desired termios settings.
 378 *      @old: old termios (or NULL)
 379 *      @min: minimum acceptable baud rate
 380 *      @max: maximum acceptable baud rate
 381 *
 382 *      Decode the termios structure into a numeric baud rate,
 383 *      taking account of the magic 38400 baud rate (with spd_*
 384 *      flags), and mapping the %B0 rate to 9600 baud.
 385 *
 386 *      If the new baud rate is invalid, try the old termios setting.
 387 *      If it's still invalid, we try 9600 baud.
 388 *
 389 *      Update the @termios structure to reflect the baud rate
 390 *      we're actually going to be using. Don't do this for the case
 391 *      where B0 is requested ("hang up").
 392 */
 393unsigned int
 394uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 395                   struct ktermios *old, unsigned int min, unsigned int max)
 396{
 397        unsigned int try;
 398        unsigned int baud;
 399        unsigned int altbaud;
 400        int hung_up = 0;
 401        upf_t flags = port->flags & UPF_SPD_MASK;
 402
 403        switch (flags) {
 404        case UPF_SPD_HI:
 405                altbaud = 57600;
 406                break;
 407        case UPF_SPD_VHI:
 408                altbaud = 115200;
 409                break;
 410        case UPF_SPD_SHI:
 411                altbaud = 230400;
 412                break;
 413        case UPF_SPD_WARP:
 414                altbaud = 460800;
 415                break;
 416        default:
 417                altbaud = 38400;
 418                break;
 419        }
 420
 421        for (try = 0; try < 2; try++) {
 422                baud = tty_termios_baud_rate(termios);
 423
 424                /*
 425                 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
 426                 * Die! Die! Die!
 427                 */
 428                if (try == 0 && baud == 38400)
 429                        baud = altbaud;
 430
 431                /*
 432                 * Special case: B0 rate.
 433                 */
 434                if (baud == 0) {
 435                        hung_up = 1;
 436                        baud = 9600;
 437                }
 438
 439                if (baud >= min && baud <= max)
 440                        return baud;
 441
 442                /*
 443                 * Oops, the quotient was zero.  Try again with
 444                 * the old baud rate if possible.
 445                 */
 446                termios->c_cflag &= ~CBAUD;
 447                if (old) {
 448                        baud = tty_termios_baud_rate(old);
 449                        if (!hung_up)
 450                                tty_termios_encode_baud_rate(termios,
 451                                                                baud, baud);
 452                        old = NULL;
 453                        continue;
 454                }
 455
 456                /*
 457                 * As a last resort, if the range cannot be met then clip to
 458                 * the nearest chip supported rate.
 459                 */
 460                if (!hung_up) {
 461                        if (baud <= min)
 462                                tty_termios_encode_baud_rate(termios,
 463                                                        min + 1, min + 1);
 464                        else
 465                                tty_termios_encode_baud_rate(termios,
 466                                                        max - 1, max - 1);
 467                }
 468        }
 469        /* Should never happen */
 470        WARN_ON(1);
 471        return 0;
 472}
 473
 474EXPORT_SYMBOL(uart_get_baud_rate);
 475
 476/**
 477 *      uart_get_divisor - return uart clock divisor
 478 *      @port: uart_port structure describing the port.
 479 *      @baud: desired baud rate
 480 *
 481 *      Calculate the uart clock divisor for the port.
 482 */
 483unsigned int
 484uart_get_divisor(struct uart_port *port, unsigned int baud)
 485{
 486        unsigned int quot;
 487
 488        /*
 489         * Old custom speed handling.
 490         */
 491        if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 492                quot = port->custom_divisor;
 493        else
 494                quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
 495
 496        return quot;
 497}
 498
 499EXPORT_SYMBOL(uart_get_divisor);
 500
 501/* Caller holds port mutex */
 502static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
 503                                        struct ktermios *old_termios)
 504{
 505        struct uart_port *uport = uart_port_check(state);
 506        struct ktermios *termios;
 507        int hw_stopped;
 508
 509        /*
 510         * If we have no tty, termios, or the port does not exist,
 511         * then we can't set the parameters for this port.
 512         */
 513        if (!tty || uport->type == PORT_UNKNOWN)
 514                return;
 515
 516        termios = &tty->termios;
 517        uport->ops->set_termios(uport, termios, old_termios);
 518
 519        /*
 520         * Set modem status enables based on termios cflag
 521         */
 522        spin_lock_irq(&uport->lock);
 523        if (termios->c_cflag & CRTSCTS)
 524                uport->status |= UPSTAT_CTS_ENABLE;
 525        else
 526                uport->status &= ~UPSTAT_CTS_ENABLE;
 527
 528        if (termios->c_cflag & CLOCAL)
 529                uport->status &= ~UPSTAT_DCD_ENABLE;
 530        else
 531                uport->status |= UPSTAT_DCD_ENABLE;
 532
 533        /* reset sw-assisted CTS flow control based on (possibly) new mode */
 534        hw_stopped = uport->hw_stopped;
 535        uport->hw_stopped = uart_softcts_mode(uport) &&
 536                                !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
 537        if (uport->hw_stopped) {
 538                if (!hw_stopped)
 539                        uport->ops->stop_tx(uport);
 540        } else {
 541                if (hw_stopped)
 542                        __uart_start(tty);
 543        }
 544        spin_unlock_irq(&uport->lock);
 545}
 546
 547static int uart_put_char(struct tty_struct *tty, unsigned char c)
 548{
 549        struct uart_state *state = tty->driver_data;
 550        struct uart_port *port;
 551        struct circ_buf *circ;
 552        unsigned long flags;
 553        int ret = 0;
 554
 555        circ = &state->xmit;
 556        port = uart_port_lock(state, flags);
 557        if (!circ->buf) {
 558                uart_port_unlock(port, flags);
 559                return 0;
 560        }
 561
 562        if (port && uart_circ_chars_free(circ) != 0) {
 563                circ->buf[circ->head] = c;
 564                circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
 565                ret = 1;
 566        }
 567        uart_port_unlock(port, flags);
 568        return ret;
 569}
 570
 571static void uart_flush_chars(struct tty_struct *tty)
 572{
 573        uart_start(tty);
 574}
 575
 576static int uart_write(struct tty_struct *tty,
 577                                        const unsigned char *buf, int count)
 578{
 579        struct uart_state *state = tty->driver_data;
 580        struct uart_port *port;
 581        struct circ_buf *circ;
 582        unsigned long flags;
 583        int c, ret = 0;
 584
 585        /*
 586         * This means you called this function _after_ the port was
 587         * closed.  No cookie for you.
 588         */
 589        if (!state) {
 590                WARN_ON(1);
 591                return -EL3HLT;
 592        }
 593
 594        port = uart_port_lock(state, flags);
 595        circ = &state->xmit;
 596        if (!circ->buf) {
 597                uart_port_unlock(port, flags);
 598                return 0;
 599        }
 600
 601        while (port) {
 602                c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
 603                if (count < c)
 604                        c = count;
 605                if (c <= 0)
 606                        break;
 607                memcpy(circ->buf + circ->head, buf, c);
 608                circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
 609                buf += c;
 610                count -= c;
 611                ret += c;
 612        }
 613
 614        __uart_start(tty);
 615        uart_port_unlock(port, flags);
 616        return ret;
 617}
 618
 619static int uart_write_room(struct tty_struct *tty)
 620{
 621        struct uart_state *state = tty->driver_data;
 622        struct uart_port *port;
 623        unsigned long flags;
 624        int ret;
 625
 626        port = uart_port_lock(state, flags);
 627        ret = uart_circ_chars_free(&state->xmit);
 628        uart_port_unlock(port, flags);
 629        return ret;
 630}
 631
 632static int uart_chars_in_buffer(struct tty_struct *tty)
 633{
 634        struct uart_state *state = tty->driver_data;
 635        struct uart_port *port;
 636        unsigned long flags;
 637        int ret;
 638
 639        port = uart_port_lock(state, flags);
 640        ret = uart_circ_chars_pending(&state->xmit);
 641        uart_port_unlock(port, flags);
 642        return ret;
 643}
 644
 645static void uart_flush_buffer(struct tty_struct *tty)
 646{
 647        struct uart_state *state = tty->driver_data;
 648        struct uart_port *port;
 649        unsigned long flags;
 650
 651        /*
 652         * This means you called this function _after_ the port was
 653         * closed.  No cookie for you.
 654         */
 655        if (!state) {
 656                WARN_ON(1);
 657                return;
 658        }
 659
 660        pr_debug("uart_flush_buffer(%d) called\n", tty->index);
 661
 662        port = uart_port_lock(state, flags);
 663        if (!port)
 664                return;
 665        uart_circ_clear(&state->xmit);
 666        if (port->ops->flush_buffer)
 667                port->ops->flush_buffer(port);
 668        uart_port_unlock(port, flags);
 669        tty_port_tty_wakeup(&state->port);
 670}
 671
 672/*
 673 * This function is used to send a high-priority XON/XOFF character to
 674 * the device
 675 */
 676static void uart_send_xchar(struct tty_struct *tty, char ch)
 677{
 678        struct uart_state *state = tty->driver_data;
 679        struct uart_port *port;
 680        unsigned long flags;
 681
 682        port = uart_port_ref(state);
 683        if (!port)
 684                return;
 685
 686        if (port->ops->send_xchar)
 687                port->ops->send_xchar(port, ch);
 688        else {
 689                spin_lock_irqsave(&port->lock, flags);
 690                port->x_char = ch;
 691                if (ch)
 692                        port->ops->start_tx(port);
 693                spin_unlock_irqrestore(&port->lock, flags);
 694        }
 695        uart_port_deref(port);
 696}
 697
 698static void uart_throttle(struct tty_struct *tty)
 699{
 700        struct uart_state *state = tty->driver_data;
 701        upstat_t mask = UPSTAT_SYNC_FIFO;
 702        struct uart_port *port;
 703
 704        port = uart_port_ref(state);
 705        if (!port)
 706                return;
 707
 708        if (I_IXOFF(tty))
 709                mask |= UPSTAT_AUTOXOFF;
 710        if (C_CRTSCTS(tty))
 711                mask |= UPSTAT_AUTORTS;
 712
 713        if (port->status & mask) {
 714                port->ops->throttle(port);
 715                mask &= ~port->status;
 716        }
 717
 718        if (mask & UPSTAT_AUTORTS)
 719                uart_clear_mctrl(port, TIOCM_RTS);
 720
 721        if (mask & UPSTAT_AUTOXOFF)
 722                uart_send_xchar(tty, STOP_CHAR(tty));
 723
 724        uart_port_deref(port);
 725}
 726
 727static void uart_unthrottle(struct tty_struct *tty)
 728{
 729        struct uart_state *state = tty->driver_data;
 730        upstat_t mask = UPSTAT_SYNC_FIFO;
 731        struct uart_port *port;
 732
 733        port = uart_port_ref(state);
 734        if (!port)
 735                return;
 736
 737        if (I_IXOFF(tty))
 738                mask |= UPSTAT_AUTOXOFF;
 739        if (C_CRTSCTS(tty))
 740                mask |= UPSTAT_AUTORTS;
 741
 742        if (port->status & mask) {
 743                port->ops->unthrottle(port);
 744                mask &= ~port->status;
 745        }
 746
 747        if (mask & UPSTAT_AUTORTS)
 748                uart_set_mctrl(port, TIOCM_RTS);
 749
 750        if (mask & UPSTAT_AUTOXOFF)
 751                uart_send_xchar(tty, START_CHAR(tty));
 752
 753        uart_port_deref(port);
 754}
 755
 756static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 757{
 758        struct uart_state *state = container_of(port, struct uart_state, port);
 759        struct uart_port *uport;
 760        int ret = -ENODEV;
 761
 762        /*
 763         * Ensure the state we copy is consistent and no hardware changes
 764         * occur as we go
 765         */
 766        mutex_lock(&port->mutex);
 767        uport = uart_port_check(state);
 768        if (!uport)
 769                goto out;
 770
 771        retinfo->type       = uport->type;
 772        retinfo->line       = uport->line;
 773        retinfo->port       = uport->iobase;
 774        if (HIGH_BITS_OFFSET)
 775                retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
 776        retinfo->irq                = uport->irq;
 777        retinfo->flags      = (__force int)uport->flags;
 778        retinfo->xmit_fifo_size  = uport->fifosize;
 779        retinfo->baud_base          = uport->uartclk / 16;
 780        retinfo->close_delay        = jiffies_to_msecs(port->close_delay) / 10;
 781        retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 782                                ASYNC_CLOSING_WAIT_NONE :
 783                                jiffies_to_msecs(port->closing_wait) / 10;
 784        retinfo->custom_divisor  = uport->custom_divisor;
 785        retinfo->hub6       = uport->hub6;
 786        retinfo->io_type         = uport->iotype;
 787        retinfo->iomem_reg_shift = uport->regshift;
 788        retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
 789
 790        ret = 0;
 791out:
 792        mutex_unlock(&port->mutex);
 793        return ret;
 794}
 795
 796static int uart_get_info_user(struct tty_struct *tty,
 797                         struct serial_struct *ss)
 798{
 799        struct uart_state *state = tty->driver_data;
 800        struct tty_port *port = &state->port;
 801
 802        return uart_get_info(port, ss) < 0 ? -EIO : 0;
 803}
 804
 805static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 806                         struct uart_state *state,
 807                         struct serial_struct *new_info)
 808{
 809        struct uart_port *uport = uart_port_check(state);
 810        unsigned long new_port;
 811        unsigned int change_irq, change_port, closing_wait;
 812        unsigned int old_custom_divisor, close_delay;
 813        upf_t old_flags, new_flags;
 814        int retval = 0;
 815
 816        if (!uport)
 817                return -EIO;
 818
 819        new_port = new_info->port;
 820        if (HIGH_BITS_OFFSET)
 821                new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
 822
 823        new_info->irq = irq_canonicalize(new_info->irq);
 824        close_delay = msecs_to_jiffies(new_info->close_delay * 10);
 825        closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 826                        ASYNC_CLOSING_WAIT_NONE :
 827                        msecs_to_jiffies(new_info->closing_wait * 10);
 828
 829
 830        change_irq  = !(uport->flags & UPF_FIXED_PORT)
 831                && new_info->irq != uport->irq;
 832
 833        /*
 834         * Since changing the 'type' of the port changes its resource
 835         * allocations, we should treat type changes the same as
 836         * IO port changes.
 837         */
 838        change_port = !(uport->flags & UPF_FIXED_PORT)
 839                && (new_port != uport->iobase ||
 840                    (unsigned long)new_info->iomem_base != uport->mapbase ||
 841                    new_info->hub6 != uport->hub6 ||
 842                    new_info->io_type != uport->iotype ||
 843                    new_info->iomem_reg_shift != uport->regshift ||
 844                    new_info->type != uport->type);
 845
 846        old_flags = uport->flags;
 847        new_flags = (__force upf_t)new_info->flags;
 848        old_custom_divisor = uport->custom_divisor;
 849
 850        if (!capable(CAP_SYS_ADMIN)) {
 851                retval = -EPERM;
 852                if (change_irq || change_port ||
 853                    (new_info->baud_base != uport->uartclk / 16) ||
 854                    (close_delay != port->close_delay) ||
 855                    (closing_wait != port->closing_wait) ||
 856                    (new_info->xmit_fifo_size &&
 857                     new_info->xmit_fifo_size != uport->fifosize) ||
 858                    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
 859                        goto exit;
 860                uport->flags = ((uport->flags & ~UPF_USR_MASK) |
 861                               (new_flags & UPF_USR_MASK));
 862                uport->custom_divisor = new_info->custom_divisor;
 863                goto check_and_exit;
 864        }
 865
 866        if (change_irq || change_port) {
 867                retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
 868                if (retval)
 869                        goto exit;
 870        }
 871
 872        /*
 873         * Ask the low level driver to verify the settings.
 874         */
 875        if (uport->ops->verify_port)
 876                retval = uport->ops->verify_port(uport, new_info);
 877
 878        if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
 879            (new_info->baud_base < 9600))
 880                retval = -EINVAL;
 881
 882        if (retval)
 883                goto exit;
 884
 885        if (change_port || change_irq) {
 886                retval = -EBUSY;
 887
 888                /*
 889                 * Make sure that we are the sole user of this port.
 890                 */
 891                if (tty_port_users(port) > 1)
 892                        goto exit;
 893
 894                /*
 895                 * We need to shutdown the serial port at the old
 896                 * port/type/irq combination.
 897                 */
 898                uart_shutdown(tty, state);
 899        }
 900
 901        if (change_port) {
 902                unsigned long old_iobase, old_mapbase;
 903                unsigned int old_type, old_iotype, old_hub6, old_shift;
 904
 905                old_iobase = uport->iobase;
 906                old_mapbase = uport->mapbase;
 907                old_type = uport->type;
 908                old_hub6 = uport->hub6;
 909                old_iotype = uport->iotype;
 910                old_shift = uport->regshift;
 911
 912                /*
 913                 * Free and release old regions
 914                 */
 915                if (old_type != PORT_UNKNOWN && uport->ops->release_port)
 916                        uport->ops->release_port(uport);
 917
 918                uport->iobase = new_port;
 919                uport->type = new_info->type;
 920                uport->hub6 = new_info->hub6;
 921                uport->iotype = new_info->io_type;
 922                uport->regshift = new_info->iomem_reg_shift;
 923                uport->mapbase = (unsigned long)new_info->iomem_base;
 924
 925                /*
 926                 * Claim and map the new regions
 927                 */
 928                if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
 929                        retval = uport->ops->request_port(uport);
 930                } else {
 931                        /* Always success - Jean II */
 932                        retval = 0;
 933                }
 934
 935                /*
 936                 * If we fail to request resources for the
 937                 * new port, try to restore the old settings.
 938                 */
 939                if (retval) {
 940                        uport->iobase = old_iobase;
 941                        uport->type = old_type;
 942                        uport->hub6 = old_hub6;
 943                        uport->iotype = old_iotype;
 944                        uport->regshift = old_shift;
 945                        uport->mapbase = old_mapbase;
 946
 947                        if (old_type != PORT_UNKNOWN) {
 948                                retval = uport->ops->request_port(uport);
 949                                /*
 950                                 * If we failed to restore the old settings,
 951                                 * we fail like this.
 952                                 */
 953                                if (retval)
 954                                        uport->type = PORT_UNKNOWN;
 955
 956                                /*
 957                                 * We failed anyway.
 958                                 */
 959                                retval = -EBUSY;
 960                        }
 961
 962                        /* Added to return the correct error -Ram Gupta */
 963                        goto exit;
 964                }
 965        }
 966
 967        if (change_irq)
 968                uport->irq      = new_info->irq;
 969        if (!(uport->flags & UPF_FIXED_PORT))
 970                uport->uartclk  = new_info->baud_base * 16;
 971        uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
 972                                 (new_flags & UPF_CHANGE_MASK);
 973        uport->custom_divisor   = new_info->custom_divisor;
 974        port->close_delay     = close_delay;
 975        port->closing_wait    = closing_wait;
 976        if (new_info->xmit_fifo_size)
 977                uport->fifosize = new_info->xmit_fifo_size;
 978
 979 check_and_exit:
 980        retval = 0;
 981        if (uport->type == PORT_UNKNOWN)
 982                goto exit;
 983        if (tty_port_initialized(port)) {
 984                if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
 985                    old_custom_divisor != uport->custom_divisor) {
 986                        /*
 987                         * If they're setting up a custom divisor or speed,
 988                         * instead of clearing it, then bitch about it.
 989                         */
 990                        if (uport->flags & UPF_SPD_MASK) {
 991                                dev_notice_ratelimited(uport->dev,
 992                                       "%s sets custom speed on %s. This is deprecated.\n",
 993                                      current->comm,
 994                                      tty_name(port->tty));
 995                        }
 996                        uart_change_speed(tty, state, NULL);
 997                }
 998        } else {
 999                retval = uart_startup(tty, state, 1);
1000                if (retval == 0)
1001                        tty_port_set_initialized(port, true);
1002                if (retval > 0)
1003                        retval = 0;
1004        }
1005 exit:
1006        return retval;
1007}
1008
1009static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1010{
1011        struct uart_state *state = tty->driver_data;
1012        struct tty_port *port = &state->port;
1013        int retval;
1014
1015        down_write(&tty->termios_rwsem);
1016        /*
1017         * This semaphore protects port->count.  It is also
1018         * very useful to prevent opens.  Also, take the
1019         * port configuration semaphore to make sure that a
1020         * module insertion/removal doesn't change anything
1021         * under us.
1022         */
1023        mutex_lock(&port->mutex);
1024        retval = uart_set_info(tty, port, state, ss);
1025        mutex_unlock(&port->mutex);
1026        up_write(&tty->termios_rwsem);
1027        return retval;
1028}
1029
1030/**
1031 *      uart_get_lsr_info       -       get line status register info
1032 *      @tty: tty associated with the UART
1033 *      @state: UART being queried
1034 *      @value: returned modem value
1035 */
1036static int uart_get_lsr_info(struct tty_struct *tty,
1037                        struct uart_state *state, unsigned int __user *value)
1038{
1039        struct uart_port *uport = uart_port_check(state);
1040        unsigned int result;
1041
1042        result = uport->ops->tx_empty(uport);
1043
1044        /*
1045         * If we're about to load something into the transmit
1046         * register, we'll pretend the transmitter isn't empty to
1047         * avoid a race condition (depending on when the transmit
1048         * interrupt happens).
1049         */
1050        if (uport->x_char ||
1051            ((uart_circ_chars_pending(&state->xmit) > 0) &&
1052             !uart_tx_stopped(uport)))
1053                result &= ~TIOCSER_TEMT;
1054
1055        return put_user(result, value);
1056}
1057
1058static int uart_tiocmget(struct tty_struct *tty)
1059{
1060        struct uart_state *state = tty->driver_data;
1061        struct tty_port *port = &state->port;
1062        struct uart_port *uport;
1063        int result = -EIO;
1064
1065        mutex_lock(&port->mutex);
1066        uport = uart_port_check(state);
1067        if (!uport)
1068                goto out;
1069
1070        if (!tty_io_error(tty)) {
1071                result = uport->mctrl;
1072                spin_lock_irq(&uport->lock);
1073                result |= uport->ops->get_mctrl(uport);
1074                spin_unlock_irq(&uport->lock);
1075        }
1076out:
1077        mutex_unlock(&port->mutex);
1078        return result;
1079}
1080
1081static int
1082uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1083{
1084        struct uart_state *state = tty->driver_data;
1085        struct tty_port *port = &state->port;
1086        struct uart_port *uport;
1087        int ret = -EIO;
1088
1089        mutex_lock(&port->mutex);
1090        uport = uart_port_check(state);
1091        if (!uport)
1092                goto out;
1093
1094        if (!tty_io_error(tty)) {
1095                uart_update_mctrl(uport, set, clear);
1096                ret = 0;
1097        }
1098out:
1099        mutex_unlock(&port->mutex);
1100        return ret;
1101}
1102
1103static int uart_break_ctl(struct tty_struct *tty, int break_state)
1104{
1105        struct uart_state *state = tty->driver_data;
1106        struct tty_port *port = &state->port;
1107        struct uart_port *uport;
1108        int ret = -EIO;
1109
1110        mutex_lock(&port->mutex);
1111        uport = uart_port_check(state);
1112        if (!uport)
1113                goto out;
1114
1115        if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1116                uport->ops->break_ctl(uport, break_state);
1117        ret = 0;
1118out:
1119        mutex_unlock(&port->mutex);
1120        return ret;
1121}
1122
1123static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1124{
1125        struct tty_port *port = &state->port;
1126        struct uart_port *uport;
1127        int flags, ret;
1128
1129        if (!capable(CAP_SYS_ADMIN))
1130                return -EPERM;
1131
1132        /*
1133         * Take the per-port semaphore.  This prevents count from
1134         * changing, and hence any extra opens of the port while
1135         * we're auto-configuring.
1136         */
1137        if (mutex_lock_interruptible(&port->mutex))
1138                return -ERESTARTSYS;
1139
1140        uport = uart_port_check(state);
1141        if (!uport) {
1142                ret = -EIO;
1143                goto out;
1144        }
1145
1146        ret = -EBUSY;
1147        if (tty_port_users(port) == 1) {
1148                uart_shutdown(tty, state);
1149
1150                /*
1151                 * If we already have a port type configured,
1152                 * we must release its resources.
1153                 */
1154                if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1155                        uport->ops->release_port(uport);
1156
1157                flags = UART_CONFIG_TYPE;
1158                if (uport->flags & UPF_AUTO_IRQ)
1159                        flags |= UART_CONFIG_IRQ;
1160
1161                /*
1162                 * This will claim the ports resources if
1163                 * a port is found.
1164                 */
1165                uport->ops->config_port(uport, flags);
1166
1167                ret = uart_startup(tty, state, 1);
1168                if (ret == 0)
1169                        tty_port_set_initialized(port, true);
1170                if (ret > 0)
1171                        ret = 0;
1172        }
1173out:
1174        mutex_unlock(&port->mutex);
1175        return ret;
1176}
1177
1178static void uart_enable_ms(struct uart_port *uport)
1179{
1180        /*
1181         * Force modem status interrupts on
1182         */
1183        if (uport->ops->enable_ms)
1184                uport->ops->enable_ms(uport);
1185}
1186
1187/*
1188 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1189 * - mask passed in arg for lines of interest
1190 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1191 * Caller should use TIOCGICOUNT to see which one it was
1192 *
1193 * FIXME: This wants extracting into a common all driver implementation
1194 * of TIOCMWAIT using tty_port.
1195 */
1196static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1197{
1198        struct uart_port *uport;
1199        struct tty_port *port = &state->port;
1200        DECLARE_WAITQUEUE(wait, current);
1201        struct uart_icount cprev, cnow;
1202        int ret;
1203
1204        /*
1205         * note the counters on entry
1206         */
1207        uport = uart_port_ref(state);
1208        if (!uport)
1209                return -EIO;
1210        spin_lock_irq(&uport->lock);
1211        memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1212        uart_enable_ms(uport);
1213        spin_unlock_irq(&uport->lock);
1214
1215        add_wait_queue(&port->delta_msr_wait, &wait);
1216        for (;;) {
1217                spin_lock_irq(&uport->lock);
1218                memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1219                spin_unlock_irq(&uport->lock);
1220
1221                set_current_state(TASK_INTERRUPTIBLE);
1222
1223                if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1224                    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1225                    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1226                    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1227                        ret = 0;
1228                        break;
1229                }
1230
1231                schedule();
1232
1233                /* see if a signal did it */
1234                if (signal_pending(current)) {
1235                        ret = -ERESTARTSYS;
1236                        break;
1237                }
1238
1239                cprev = cnow;
1240        }
1241        __set_current_state(TASK_RUNNING);
1242        remove_wait_queue(&port->delta_msr_wait, &wait);
1243        uart_port_deref(uport);
1244
1245        return ret;
1246}
1247
1248/*
1249 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1250 * Return: write counters to the user passed counter struct
1251 * NB: both 1->0 and 0->1 transitions are counted except for
1252 *     RI where only 0->1 is counted.
1253 */
1254static int uart_get_icount(struct tty_struct *tty,
1255                          struct serial_icounter_struct *icount)
1256{
1257        struct uart_state *state = tty->driver_data;
1258        struct uart_icount cnow;
1259        struct uart_port *uport;
1260
1261        uport = uart_port_ref(state);
1262        if (!uport)
1263                return -EIO;
1264        spin_lock_irq(&uport->lock);
1265        memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1266        spin_unlock_irq(&uport->lock);
1267        uart_port_deref(uport);
1268
1269        icount->cts         = cnow.cts;
1270        icount->dsr         = cnow.dsr;
1271        icount->rng         = cnow.rng;
1272        icount->dcd         = cnow.dcd;
1273        icount->rx          = cnow.rx;
1274        icount->tx          = cnow.tx;
1275        icount->frame       = cnow.frame;
1276        icount->overrun     = cnow.overrun;
1277        icount->parity      = cnow.parity;
1278        icount->brk         = cnow.brk;
1279        icount->buf_overrun = cnow.buf_overrun;
1280
1281        return 0;
1282}
1283
1284static int uart_get_rs485_config(struct uart_port *port,
1285                         struct serial_rs485 __user *rs485)
1286{
1287        unsigned long flags;
1288        struct serial_rs485 aux;
1289
1290        spin_lock_irqsave(&port->lock, flags);
1291        aux = port->rs485;
1292        spin_unlock_irqrestore(&port->lock, flags);
1293
1294        if (copy_to_user(rs485, &aux, sizeof(aux)))
1295                return -EFAULT;
1296
1297        return 0;
1298}
1299
1300static int uart_set_rs485_config(struct uart_port *port,
1301                         struct serial_rs485 __user *rs485_user)
1302{
1303        struct serial_rs485 rs485;
1304        int ret;
1305        unsigned long flags;
1306
1307        if (!port->rs485_config)
1308                return -ENOTTY;
1309
1310        if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1311                return -EFAULT;
1312
1313        spin_lock_irqsave(&port->lock, flags);
1314        ret = port->rs485_config(port, &rs485);
1315        spin_unlock_irqrestore(&port->lock, flags);
1316        if (ret)
1317                return ret;
1318
1319        if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1320                return -EFAULT;
1321
1322        return 0;
1323}
1324
1325static int uart_get_iso7816_config(struct uart_port *port,
1326                                   struct serial_iso7816 __user *iso7816)
1327{
1328        unsigned long flags;
1329        struct serial_iso7816 aux;
1330
1331        if (!port->iso7816_config)
1332                return -ENOTTY;
1333
1334        spin_lock_irqsave(&port->lock, flags);
1335        aux = port->iso7816;
1336        spin_unlock_irqrestore(&port->lock, flags);
1337
1338        if (copy_to_user(iso7816, &aux, sizeof(aux)))
1339                return -EFAULT;
1340
1341        return 0;
1342}
1343
1344static int uart_set_iso7816_config(struct uart_port *port,
1345                                   struct serial_iso7816 __user *iso7816_user)
1346{
1347        struct serial_iso7816 iso7816;
1348        int i, ret;
1349        unsigned long flags;
1350
1351        if (!port->iso7816_config)
1352                return -ENOTTY;
1353
1354        if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1355                return -EFAULT;
1356
1357        /*
1358         * There are 5 words reserved for future use. Check that userspace
1359         * doesn't put stuff in there to prevent breakages in the future.
1360         */
1361        for (i = 0; i < 5; i++)
1362                if (iso7816.reserved[i])
1363                        return -EINVAL;
1364
1365        spin_lock_irqsave(&port->lock, flags);
1366        ret = port->iso7816_config(port, &iso7816);
1367        spin_unlock_irqrestore(&port->lock, flags);
1368        if (ret)
1369                return ret;
1370
1371        if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1372                return -EFAULT;
1373
1374        return 0;
1375}
1376
1377/*
1378 * Called via sys_ioctl.  We can use spin_lock_irq() here.
1379 */
1380static int
1381uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1382{
1383        struct uart_state *state = tty->driver_data;
1384        struct tty_port *port = &state->port;
1385        struct uart_port *uport;
1386        void __user *uarg = (void __user *)arg;
1387        int ret = -ENOIOCTLCMD;
1388
1389
1390        /*
1391         * These ioctls don't rely on the hardware to be present.
1392         */
1393        switch (cmd) {
1394        case TIOCSERCONFIG:
1395                down_write(&tty->termios_rwsem);
1396                ret = uart_do_autoconfig(tty, state);
1397                up_write(&tty->termios_rwsem);
1398                break;
1399        }
1400
1401        if (ret != -ENOIOCTLCMD)
1402                goto out;
1403
1404        if (tty_io_error(tty)) {
1405                ret = -EIO;
1406                goto out;
1407        }
1408
1409        /*
1410         * The following should only be used when hardware is present.
1411         */
1412        switch (cmd) {
1413        case TIOCMIWAIT:
1414                ret = uart_wait_modem_status(state, arg);
1415                break;
1416        }
1417
1418        if (ret != -ENOIOCTLCMD)
1419                goto out;
1420
1421        mutex_lock(&port->mutex);
1422        uport = uart_port_check(state);
1423
1424        if (!uport || tty_io_error(tty)) {
1425                ret = -EIO;
1426                goto out_up;
1427        }
1428
1429        /*
1430         * All these rely on hardware being present and need to be
1431         * protected against the tty being hung up.
1432         */
1433
1434        switch (cmd) {
1435        case TIOCSERGETLSR: /* Get line status register */
1436                ret = uart_get_lsr_info(tty, state, uarg);
1437                break;
1438
1439        case TIOCGRS485:
1440                ret = uart_get_rs485_config(uport, uarg);
1441                break;
1442
1443        case TIOCSRS485:
1444                ret = uart_set_rs485_config(uport, uarg);
1445                break;
1446
1447        case TIOCSISO7816:
1448                ret = uart_set_iso7816_config(state->uart_port, uarg);
1449                break;
1450
1451        case TIOCGISO7816:
1452                ret = uart_get_iso7816_config(state->uart_port, uarg);
1453                break;
1454        default:
1455                if (uport->ops->ioctl)
1456                        ret = uport->ops->ioctl(uport, cmd, arg);
1457                break;
1458        }
1459out_up:
1460        mutex_unlock(&port->mutex);
1461out:
1462        return ret;
1463}
1464
1465static void uart_set_ldisc(struct tty_struct *tty)
1466{
1467        struct uart_state *state = tty->driver_data;
1468        struct uart_port *uport;
1469        struct tty_port *port = &state->port;
1470
1471        if (!tty_port_initialized(port))
1472                return;
1473
1474        mutex_lock(&state->port.mutex);
1475        uport = uart_port_check(state);
1476        if (uport && uport->ops->set_ldisc)
1477                uport->ops->set_ldisc(uport, &tty->termios);
1478        mutex_unlock(&state->port.mutex);
1479}
1480
1481static void uart_set_termios(struct tty_struct *tty,
1482                                                struct ktermios *old_termios)
1483{
1484        struct uart_state *state = tty->driver_data;
1485        struct uart_port *uport;
1486        unsigned int cflag = tty->termios.c_cflag;
1487        unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1488        bool sw_changed = false;
1489
1490        mutex_lock(&state->port.mutex);
1491        uport = uart_port_check(state);
1492        if (!uport)
1493                goto out;
1494
1495        /*
1496         * Drivers doing software flow control also need to know
1497         * about changes to these input settings.
1498         */
1499        if (uport->flags & UPF_SOFT_FLOW) {
1500                iflag_mask |= IXANY|IXON|IXOFF;
1501                sw_changed =
1502                   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1503                   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1504        }
1505
1506        /*
1507         * These are the bits that are used to setup various
1508         * flags in the low level driver. We can ignore the Bfoo
1509         * bits in c_cflag; c_[io]speed will always be set
1510         * appropriately by set_termios() in tty_ioctl.c
1511         */
1512        if ((cflag ^ old_termios->c_cflag) == 0 &&
1513            tty->termios.c_ospeed == old_termios->c_ospeed &&
1514            tty->termios.c_ispeed == old_termios->c_ispeed &&
1515            ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1516            !sw_changed) {
1517                goto out;
1518        }
1519
1520        uart_change_speed(tty, state, old_termios);
1521        /* reload cflag from termios; port driver may have overridden flags */
1522        cflag = tty->termios.c_cflag;
1523
1524        /* Handle transition to B0 status */
1525        if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1526                uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1527        /* Handle transition away from B0 status */
1528        else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1529                unsigned int mask = TIOCM_DTR;
1530
1531                if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1532                        mask |= TIOCM_RTS;
1533                uart_set_mctrl(uport, mask);
1534        }
1535out:
1536        mutex_unlock(&state->port.mutex);
1537}
1538
1539/*
1540 * Calls to uart_close() are serialised via the tty_lock in
1541 *   drivers/tty/tty_io.c:tty_release()
1542 *   drivers/tty/tty_io.c:do_tty_hangup()
1543 */
1544static void uart_close(struct tty_struct *tty, struct file *filp)
1545{
1546        struct uart_state *state = tty->driver_data;
1547
1548        if (!state) {
1549                struct uart_driver *drv = tty->driver->driver_state;
1550                struct tty_port *port;
1551
1552                state = drv->state + tty->index;
1553                port = &state->port;
1554                spin_lock_irq(&port->lock);
1555                --port->count;
1556                spin_unlock_irq(&port->lock);
1557                return;
1558        }
1559
1560        pr_debug("uart_close(%d) called\n", tty->index);
1561
1562        tty_port_close(tty->port, tty, filp);
1563}
1564
1565static void uart_tty_port_shutdown(struct tty_port *port)
1566{
1567        struct uart_state *state = container_of(port, struct uart_state, port);
1568        struct uart_port *uport = uart_port_check(state);
1569
1570        /*
1571         * At this point, we stop accepting input.  To do this, we
1572         * disable the receive line status interrupts.
1573         */
1574        if (WARN(!uport, "detached port still initialized!\n"))
1575                return;
1576
1577        spin_lock_irq(&uport->lock);
1578        uport->ops->stop_rx(uport);
1579        spin_unlock_irq(&uport->lock);
1580
1581        uart_port_shutdown(port);
1582
1583        /*
1584         * It's possible for shutdown to be called after suspend if we get
1585         * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1586         * we don't try to resume a port that has been shutdown.
1587         */
1588        tty_port_set_suspended(port, 0);
1589
1590        uart_change_pm(state, UART_PM_STATE_OFF);
1591
1592}
1593
1594static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1595{
1596        struct uart_state *state = tty->driver_data;
1597        struct uart_port *port;
1598        unsigned long char_time, expire;
1599
1600        port = uart_port_ref(state);
1601        if (!port)
1602                return;
1603
1604        if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1605                uart_port_deref(port);
1606                return;
1607        }
1608
1609        /*
1610         * Set the check interval to be 1/5 of the estimated time to
1611         * send a single character, and make it at least 1.  The check
1612         * interval should also be less than the timeout.
1613         *
1614         * Note: we have to use pretty tight timings here to satisfy
1615         * the NIST-PCTS.
1616         */
1617        char_time = (port->timeout - HZ/50) / port->fifosize;
1618        char_time = char_time / 5;
1619        if (char_time == 0)
1620                char_time = 1;
1621        if (timeout && timeout < char_time)
1622                char_time = timeout;
1623
1624        /*
1625         * If the transmitter hasn't cleared in twice the approximate
1626         * amount of time to send the entire FIFO, it probably won't
1627         * ever clear.  This assumes the UART isn't doing flow
1628         * control, which is currently the case.  Hence, if it ever
1629         * takes longer than port->timeout, this is probably due to a
1630         * UART bug of some kind.  So, we clamp the timeout parameter at
1631         * 2*port->timeout.
1632         */
1633        if (timeout == 0 || timeout > 2 * port->timeout)
1634                timeout = 2 * port->timeout;
1635
1636        expire = jiffies + timeout;
1637
1638        pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1639                port->line, jiffies, expire);
1640
1641        /*
1642         * Check whether the transmitter is empty every 'char_time'.
1643         * 'timeout' / 'expire' give us the maximum amount of time
1644         * we wait.
1645         */
1646        while (!port->ops->tx_empty(port)) {
1647                msleep_interruptible(jiffies_to_msecs(char_time));
1648                if (signal_pending(current))
1649                        break;
1650                if (time_after(jiffies, expire))
1651                        break;
1652        }
1653        uart_port_deref(port);
1654}
1655
1656/*
1657 * Calls to uart_hangup() are serialised by the tty_lock in
1658 *   drivers/tty/tty_io.c:do_tty_hangup()
1659 * This runs from a workqueue and can sleep for a _short_ time only.
1660 */
1661static void uart_hangup(struct tty_struct *tty)
1662{
1663        struct uart_state *state = tty->driver_data;
1664        struct tty_port *port = &state->port;
1665        struct uart_port *uport;
1666        unsigned long flags;
1667
1668        pr_debug("uart_hangup(%d)\n", tty->index);
1669
1670        mutex_lock(&port->mutex);
1671        uport = uart_port_check(state);
1672        WARN(!uport, "hangup of detached port!\n");
1673
1674        if (tty_port_active(port)) {
1675                uart_flush_buffer(tty);
1676                uart_shutdown(tty, state);
1677                spin_lock_irqsave(&port->lock, flags);
1678                port->count = 0;
1679                spin_unlock_irqrestore(&port->lock, flags);
1680                tty_port_set_active(port, 0);
1681                tty_port_tty_set(port, NULL);
1682                if (uport && !uart_console(uport))
1683                        uart_change_pm(state, UART_PM_STATE_OFF);
1684                wake_up_interruptible(&port->open_wait);
1685                wake_up_interruptible(&port->delta_msr_wait);
1686        }
1687        mutex_unlock(&port->mutex);
1688}
1689
1690/* uport == NULL if uart_port has already been removed */
1691static void uart_port_shutdown(struct tty_port *port)
1692{
1693        struct uart_state *state = container_of(port, struct uart_state, port);
1694        struct uart_port *uport = uart_port_check(state);
1695
1696        /*
1697         * clear delta_msr_wait queue to avoid mem leaks: we may free
1698         * the irq here so the queue might never be woken up.  Note
1699         * that we won't end up waiting on delta_msr_wait again since
1700         * any outstanding file descriptors should be pointing at
1701         * hung_up_tty_fops now.
1702         */
1703        wake_up_interruptible(&port->delta_msr_wait);
1704
1705        /*
1706         * Free the IRQ and disable the port.
1707         */
1708        if (uport)
1709                uport->ops->shutdown(uport);
1710
1711        /*
1712         * Ensure that the IRQ handler isn't running on another CPU.
1713         */
1714        if (uport)
1715                synchronize_irq(uport->irq);
1716}
1717
1718static int uart_carrier_raised(struct tty_port *port)
1719{
1720        struct uart_state *state = container_of(port, struct uart_state, port);
1721        struct uart_port *uport;
1722        int mctrl;
1723
1724        uport = uart_port_ref(state);
1725        /*
1726         * Should never observe uport == NULL since checks for hangup should
1727         * abort the tty_port_block_til_ready() loop before checking for carrier
1728         * raised -- but report carrier raised if it does anyway so open will
1729         * continue and not sleep
1730         */
1731        if (WARN_ON(!uport))
1732                return 1;
1733        spin_lock_irq(&uport->lock);
1734        uart_enable_ms(uport);
1735        mctrl = uport->ops->get_mctrl(uport);
1736        spin_unlock_irq(&uport->lock);
1737        uart_port_deref(uport);
1738        if (mctrl & TIOCM_CAR)
1739                return 1;
1740        return 0;
1741}
1742
1743static void uart_dtr_rts(struct tty_port *port, int raise)
1744{
1745        struct uart_state *state = container_of(port, struct uart_state, port);
1746        struct uart_port *uport;
1747
1748        uport = uart_port_ref(state);
1749        if (!uport)
1750                return;
1751        uart_port_dtr_rts(uport, raise);
1752        uart_port_deref(uport);
1753}
1754
1755static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1756{
1757        struct uart_driver *drv = driver->driver_state;
1758        struct uart_state *state = drv->state + tty->index;
1759
1760        tty->driver_data = state;
1761
1762        return tty_standard_install(driver, tty);
1763}
1764
1765/*
1766 * Calls to uart_open are serialised by the tty_lock in
1767 *   drivers/tty/tty_io.c:tty_open()
1768 * Note that if this fails, then uart_close() _will_ be called.
1769 *
1770 * In time, we want to scrap the "opening nonpresent ports"
1771 * behaviour and implement an alternative way for setserial
1772 * to set base addresses/ports/types.  This will allow us to
1773 * get rid of a certain amount of extra tests.
1774 */
1775static int uart_open(struct tty_struct *tty, struct file *filp)
1776{
1777        struct uart_state *state = tty->driver_data;
1778        int retval;
1779
1780        retval = tty_port_open(&state->port, tty, filp);
1781        if (retval > 0)
1782                retval = 0;
1783
1784        return retval;
1785}
1786
1787static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1788{
1789        struct uart_state *state = container_of(port, struct uart_state, port);
1790        struct uart_port *uport;
1791        int ret;
1792
1793        uport = uart_port_check(state);
1794        if (!uport || uport->flags & UPF_DEAD)
1795                return -ENXIO;
1796
1797        /*
1798         * Start up the serial port.
1799         */
1800        ret = uart_startup(tty, state, 0);
1801        if (ret > 0)
1802                tty_port_set_active(port, 1);
1803
1804        return ret;
1805}
1806
1807static const char *uart_type(struct uart_port *port)
1808{
1809        const char *str = NULL;
1810
1811        if (port->ops->type)
1812                str = port->ops->type(port);
1813
1814        if (!str)
1815                str = "unknown";
1816
1817        return str;
1818}
1819
1820#ifdef CONFIG_PROC_FS
1821
1822static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1823{
1824        struct uart_state *state = drv->state + i;
1825        struct tty_port *port = &state->port;
1826        enum uart_pm_state pm_state;
1827        struct uart_port *uport;
1828        char stat_buf[32];
1829        unsigned int status;
1830        int mmio;
1831
1832        mutex_lock(&port->mutex);
1833        uport = uart_port_check(state);
1834        if (!uport)
1835                goto out;
1836
1837        mmio = uport->iotype >= UPIO_MEM;
1838        seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1839                        uport->line, uart_type(uport),
1840                        mmio ? "mmio:0x" : "port:",
1841                        mmio ? (unsigned long long)uport->mapbase
1842                             : (unsigned long long)uport->iobase,
1843                        uport->irq);
1844
1845        if (uport->type == PORT_UNKNOWN) {
1846                seq_putc(m, '\n');
1847                goto out;
1848        }
1849
1850        if (capable(CAP_SYS_ADMIN)) {
1851                pm_state = state->pm_state;
1852                if (pm_state != UART_PM_STATE_ON)
1853                        uart_change_pm(state, UART_PM_STATE_ON);
1854                spin_lock_irq(&uport->lock);
1855                status = uport->ops->get_mctrl(uport);
1856                spin_unlock_irq(&uport->lock);
1857                if (pm_state != UART_PM_STATE_ON)
1858                        uart_change_pm(state, pm_state);
1859
1860                seq_printf(m, " tx:%d rx:%d",
1861                                uport->icount.tx, uport->icount.rx);
1862                if (uport->icount.frame)
1863                        seq_printf(m, " fe:%d", uport->icount.frame);
1864                if (uport->icount.parity)
1865                        seq_printf(m, " pe:%d", uport->icount.parity);
1866                if (uport->icount.brk)
1867                        seq_printf(m, " brk:%d", uport->icount.brk);
1868                if (uport->icount.overrun)
1869                        seq_printf(m, " oe:%d", uport->icount.overrun);
1870                if (uport->icount.buf_overrun)
1871                        seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1872
1873#define INFOBIT(bit, str) \
1874        if (uport->mctrl & (bit)) \
1875                strncat(stat_buf, (str), sizeof(stat_buf) - \
1876                        strlen(stat_buf) - 2)
1877#define STATBIT(bit, str) \
1878        if (status & (bit)) \
1879                strncat(stat_buf, (str), sizeof(stat_buf) - \
1880                       strlen(stat_buf) - 2)
1881
1882                stat_buf[0] = '\0';
1883                stat_buf[1] = '\0';
1884                INFOBIT(TIOCM_RTS, "|RTS");
1885                STATBIT(TIOCM_CTS, "|CTS");
1886                INFOBIT(TIOCM_DTR, "|DTR");
1887                STATBIT(TIOCM_DSR, "|DSR");
1888                STATBIT(TIOCM_CAR, "|CD");
1889                STATBIT(TIOCM_RNG, "|RI");
1890                if (stat_buf[0])
1891                        stat_buf[0] = ' ';
1892
1893                seq_puts(m, stat_buf);
1894        }
1895        seq_putc(m, '\n');
1896#undef STATBIT
1897#undef INFOBIT
1898out:
1899        mutex_unlock(&port->mutex);
1900}
1901
1902static int uart_proc_show(struct seq_file *m, void *v)
1903{
1904        struct tty_driver *ttydrv = m->private;
1905        struct uart_driver *drv = ttydrv->driver_state;
1906        int i;
1907
1908        seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1909        for (i = 0; i < drv->nr; i++)
1910                uart_line_info(m, drv, i);
1911        return 0;
1912}
1913#endif
1914
1915static inline bool uart_console_enabled(struct uart_port *port)
1916{
1917        return uart_console(port) && (port->cons->flags & CON_ENABLED);
1918}
1919
1920static void uart_port_spin_lock_init(struct uart_port *port)
1921{
1922        spin_lock_init(&port->lock);
1923        lockdep_set_class(&port->lock, &port_lock_key);
1924}
1925
1926#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1927/**
1928 *      uart_console_write - write a console message to a serial port
1929 *      @port: the port to write the message
1930 *      @s: array of characters
1931 *      @count: number of characters in string to write
1932 *      @putchar: function to write character to port
1933 */
1934void uart_console_write(struct uart_port *port, const char *s,
1935                        unsigned int count,
1936                        void (*putchar)(struct uart_port *, int))
1937{
1938        unsigned int i;
1939
1940        for (i = 0; i < count; i++, s++) {
1941                if (*s == '\n')
1942                        putchar(port, '\r');
1943                putchar(port, *s);
1944        }
1945}
1946EXPORT_SYMBOL_GPL(uart_console_write);
1947
1948/*
1949 *      Check whether an invalid uart number has been specified, and
1950 *      if so, search for the first available port that does have
1951 *      console support.
1952 */
1953struct uart_port * __init
1954uart_get_console(struct uart_port *ports, int nr, struct console *co)
1955{
1956        int idx = co->index;
1957
1958        if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1959                                     ports[idx].membase == NULL))
1960                for (idx = 0; idx < nr; idx++)
1961                        if (ports[idx].iobase != 0 ||
1962                            ports[idx].membase != NULL)
1963                                break;
1964
1965        co->index = idx;
1966
1967        return ports + idx;
1968}
1969
1970/**
1971 *      uart_parse_earlycon - Parse earlycon options
1972 *      @p:       ptr to 2nd field (ie., just beyond '<name>,')
1973 *      @iotype:  ptr for decoded iotype (out)
1974 *      @addr:    ptr for decoded mapbase/iobase (out)
1975 *      @options: ptr for <options> field; NULL if not present (out)
1976 *
1977 *      Decodes earlycon kernel command line parameters of the form
1978 *         earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1979 *         console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1980 *
1981 *      The optional form
1982 *
1983 *         earlycon=<name>,0x<addr>,<options>
1984 *         console=<name>,0x<addr>,<options>
1985 *
1986 *      is also accepted; the returned @iotype will be UPIO_MEM.
1987 *
1988 *      Returns 0 on success or -EINVAL on failure
1989 */
1990int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1991                        char **options)
1992{
1993        if (strncmp(p, "mmio,", 5) == 0) {
1994                *iotype = UPIO_MEM;
1995                p += 5;
1996        } else if (strncmp(p, "mmio16,", 7) == 0) {
1997                *iotype = UPIO_MEM16;
1998                p += 7;
1999        } else if (strncmp(p, "mmio32,", 7) == 0) {
2000                *iotype = UPIO_MEM32;
2001                p += 7;
2002        } else if (strncmp(p, "mmio32be,", 9) == 0) {
2003                *iotype = UPIO_MEM32BE;
2004                p += 9;
2005        } else if (strncmp(p, "mmio32native,", 13) == 0) {
2006                *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2007                        UPIO_MEM32BE : UPIO_MEM32;
2008                p += 13;
2009        } else if (strncmp(p, "io,", 3) == 0) {
2010                *iotype = UPIO_PORT;
2011                p += 3;
2012        } else if (strncmp(p, "0x", 2) == 0) {
2013                *iotype = UPIO_MEM;
2014        } else {
2015                return -EINVAL;
2016        }
2017
2018        /*
2019         * Before you replace it with kstrtoull(), think about options separator
2020         * (',') it will not tolerate
2021         */
2022        *addr = simple_strtoull(p, NULL, 0);
2023        p = strchr(p, ',');
2024        if (p)
2025                p++;
2026
2027        *options = p;
2028        return 0;
2029}
2030EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2031
2032/**
2033 *      uart_parse_options - Parse serial port baud/parity/bits/flow control.
2034 *      @options: pointer to option string
2035 *      @baud: pointer to an 'int' variable for the baud rate.
2036 *      @parity: pointer to an 'int' variable for the parity.
2037 *      @bits: pointer to an 'int' variable for the number of data bits.
2038 *      @flow: pointer to an 'int' variable for the flow control character.
2039 *
2040 *      uart_parse_options decodes a string containing the serial console
2041 *      options.  The format of the string is <baud><parity><bits><flow>,
2042 *      eg: 115200n8r
2043 */
2044void
2045uart_parse_options(const char *options, int *baud, int *parity,
2046                   int *bits, int *flow)
2047{
2048        const char *s = options;
2049
2050        *baud = simple_strtoul(s, NULL, 10);
2051        while (*s >= '0' && *s <= '9')
2052                s++;
2053        if (*s)
2054                *parity = *s++;
2055        if (*s)
2056                *bits = *s++ - '0';
2057        if (*s)
2058                *flow = *s;
2059}
2060EXPORT_SYMBOL_GPL(uart_parse_options);
2061
2062/**
2063 *      uart_set_options - setup the serial console parameters
2064 *      @port: pointer to the serial ports uart_port structure
2065 *      @co: console pointer
2066 *      @baud: baud rate
2067 *      @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2068 *      @bits: number of data bits
2069 *      @flow: flow control character - 'r' (rts)
2070 */
2071int
2072uart_set_options(struct uart_port *port, struct console *co,
2073                 int baud, int parity, int bits, int flow)
2074{
2075        struct ktermios termios;
2076        static struct ktermios dummy;
2077
2078        /*
2079         * Ensure that the serial-console lock is initialised early.
2080         *
2081         * Note that the console-enabled check is needed because of kgdboc,
2082         * which can end up calling uart_set_options() for an already enabled
2083         * console via tty_find_polling_driver() and uart_poll_init().
2084         */
2085        if (!uart_console_enabled(port) && !port->console_reinit)
2086                uart_port_spin_lock_init(port);
2087
2088        memset(&termios, 0, sizeof(struct ktermios));
2089
2090        termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2091        tty_termios_encode_baud_rate(&termios, baud, baud);
2092
2093        if (bits == 7)
2094                termios.c_cflag |= CS7;
2095        else
2096                termios.c_cflag |= CS8;
2097
2098        switch (parity) {
2099        case 'o': case 'O':
2100                termios.c_cflag |= PARODD;
2101                fallthrough;
2102        case 'e': case 'E':
2103                termios.c_cflag |= PARENB;
2104                break;
2105        }
2106
2107        if (flow == 'r')
2108                termios.c_cflag |= CRTSCTS;
2109
2110        /*
2111         * some uarts on other side don't support no flow control.
2112         * So we set * DTR in host uart to make them happy
2113         */
2114        port->mctrl |= TIOCM_DTR;
2115
2116        port->ops->set_termios(port, &termios, &dummy);
2117        /*
2118         * Allow the setting of the UART parameters with a NULL console
2119         * too:
2120         */
2121        if (co)
2122                co->cflag = termios.c_cflag;
2123
2124        return 0;
2125}
2126EXPORT_SYMBOL_GPL(uart_set_options);
2127#endif /* CONFIG_SERIAL_CORE_CONSOLE */
2128
2129/**
2130 * uart_change_pm - set power state of the port
2131 *
2132 * @state: port descriptor
2133 * @pm_state: new state
2134 *
2135 * Locking: port->mutex has to be held
2136 */
2137static void uart_change_pm(struct uart_state *state,
2138                           enum uart_pm_state pm_state)
2139{
2140        struct uart_port *port = uart_port_check(state);
2141
2142        if (state->pm_state != pm_state) {
2143                if (port && port->ops->pm)
2144                        port->ops->pm(port, pm_state, state->pm_state);
2145                state->pm_state = pm_state;
2146        }
2147}
2148
2149struct uart_match {
2150        struct uart_port *port;
2151        struct uart_driver *driver;
2152};
2153
2154static int serial_match_port(struct device *dev, void *data)
2155{
2156        struct uart_match *match = data;
2157        struct tty_driver *tty_drv = match->driver->tty_driver;
2158        dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2159                match->port->line;
2160
2161        return dev->devt == devt; /* Actually, only one tty per port */
2162}
2163
2164int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2165{
2166        struct uart_state *state = drv->state + uport->line;
2167        struct tty_port *port = &state->port;
2168        struct device *tty_dev;
2169        struct uart_match match = {uport, drv};
2170
2171        mutex_lock(&port->mutex);
2172
2173        tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2174        if (tty_dev && device_may_wakeup(tty_dev)) {
2175                enable_irq_wake(uport->irq);
2176                put_device(tty_dev);
2177                mutex_unlock(&port->mutex);
2178                return 0;
2179        }
2180        put_device(tty_dev);
2181
2182        /* Nothing to do if the console is not suspending */
2183        if (!console_suspend_enabled && uart_console(uport))
2184                goto unlock;
2185
2186        uport->suspended = 1;
2187
2188        if (tty_port_initialized(port)) {
2189                const struct uart_ops *ops = uport->ops;
2190                int tries;
2191
2192                tty_port_set_suspended(port, 1);
2193                tty_port_set_initialized(port, 0);
2194
2195                spin_lock_irq(&uport->lock);
2196                ops->stop_tx(uport);
2197                ops->set_mctrl(uport, 0);
2198                ops->stop_rx(uport);
2199                spin_unlock_irq(&uport->lock);
2200
2201                /*
2202                 * Wait for the transmitter to empty.
2203                 */
2204                for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2205                        msleep(10);
2206                if (!tries)
2207                        dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2208                                uport->name);
2209
2210                ops->shutdown(uport);
2211        }
2212
2213        /*
2214         * Disable the console device before suspending.
2215         */
2216        if (uart_console(uport))
2217                console_stop(uport->cons);
2218
2219        uart_change_pm(state, UART_PM_STATE_OFF);
2220unlock:
2221        mutex_unlock(&port->mutex);
2222
2223        return 0;
2224}
2225
2226int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2227{
2228        struct uart_state *state = drv->state + uport->line;
2229        struct tty_port *port = &state->port;
2230        struct device *tty_dev;
2231        struct uart_match match = {uport, drv};
2232        struct ktermios termios;
2233
2234        mutex_lock(&port->mutex);
2235
2236        tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2237        if (!uport->suspended && device_may_wakeup(tty_dev)) {
2238                if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2239                        disable_irq_wake(uport->irq);
2240                put_device(tty_dev);
2241                mutex_unlock(&port->mutex);
2242                return 0;
2243        }
2244        put_device(tty_dev);
2245        uport->suspended = 0;
2246
2247        /*
2248         * Re-enable the console device after suspending.
2249         */
2250        if (uart_console(uport)) {
2251                /*
2252                 * First try to use the console cflag setting.
2253                 */
2254                memset(&termios, 0, sizeof(struct ktermios));
2255                termios.c_cflag = uport->cons->cflag;
2256
2257                /*
2258                 * If that's unset, use the tty termios setting.
2259                 */
2260                if (port->tty && termios.c_cflag == 0)
2261                        termios = port->tty->termios;
2262
2263                if (console_suspend_enabled)
2264                        uart_change_pm(state, UART_PM_STATE_ON);
2265                uport->ops->set_termios(uport, &termios, NULL);
2266                if (console_suspend_enabled)
2267                        console_start(uport->cons);
2268        }
2269
2270        if (tty_port_suspended(port)) {
2271                const struct uart_ops *ops = uport->ops;
2272                int ret;
2273
2274                uart_change_pm(state, UART_PM_STATE_ON);
2275                spin_lock_irq(&uport->lock);
2276                ops->set_mctrl(uport, 0);
2277                spin_unlock_irq(&uport->lock);
2278                if (console_suspend_enabled || !uart_console(uport)) {
2279                        /* Protected by port mutex for now */
2280                        struct tty_struct *tty = port->tty;
2281
2282                        ret = ops->startup(uport);
2283                        if (ret == 0) {
2284                                if (tty)
2285                                        uart_change_speed(tty, state, NULL);
2286                                spin_lock_irq(&uport->lock);
2287                                ops->set_mctrl(uport, uport->mctrl);
2288                                ops->start_tx(uport);
2289                                spin_unlock_irq(&uport->lock);
2290                                tty_port_set_initialized(port, 1);
2291                        } else {
2292                                /*
2293                                 * Failed to resume - maybe hardware went away?
2294                                 * Clear the "initialized" flag so we won't try
2295                                 * to call the low level drivers shutdown method.
2296                                 */
2297                                uart_shutdown(tty, state);
2298                        }
2299                }
2300
2301                tty_port_set_suspended(port, 0);
2302        }
2303
2304        mutex_unlock(&port->mutex);
2305
2306        return 0;
2307}
2308
2309static inline void
2310uart_report_port(struct uart_driver *drv, struct uart_port *port)
2311{
2312        char address[64];
2313
2314        switch (port->iotype) {
2315        case UPIO_PORT:
2316                snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2317                break;
2318        case UPIO_HUB6:
2319                snprintf(address, sizeof(address),
2320                         "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2321                break;
2322        case UPIO_MEM:
2323        case UPIO_MEM16:
2324        case UPIO_MEM32:
2325        case UPIO_MEM32BE:
2326        case UPIO_AU:
2327        case UPIO_TSI:
2328                snprintf(address, sizeof(address),
2329                         "MMIO 0x%llx", (unsigned long long)port->mapbase);
2330                break;
2331        default:
2332                strlcpy(address, "*unknown*", sizeof(address));
2333                break;
2334        }
2335
2336        pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2337               port->dev ? dev_name(port->dev) : "",
2338               port->dev ? ": " : "",
2339               port->name,
2340               address, port->irq, port->uartclk / 16, uart_type(port));
2341}
2342
2343static void
2344uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2345                    struct uart_port *port)
2346{
2347        unsigned int flags;
2348
2349        /*
2350         * If there isn't a port here, don't do anything further.
2351         */
2352        if (!port->iobase && !port->mapbase && !port->membase)
2353                return;
2354
2355        /*
2356         * Now do the auto configuration stuff.  Note that config_port
2357         * is expected to claim the resources and map the port for us.
2358         */
2359        flags = 0;
2360        if (port->flags & UPF_AUTO_IRQ)
2361                flags |= UART_CONFIG_IRQ;
2362        if (port->flags & UPF_BOOT_AUTOCONF) {
2363                if (!(port->flags & UPF_FIXED_TYPE)) {
2364                        port->type = PORT_UNKNOWN;
2365                        flags |= UART_CONFIG_TYPE;
2366                }
2367                port->ops->config_port(port, flags);
2368        }
2369
2370        if (port->type != PORT_UNKNOWN) {
2371                unsigned long flags;
2372
2373                uart_report_port(drv, port);
2374
2375                /* Power up port for set_mctrl() */
2376                uart_change_pm(state, UART_PM_STATE_ON);
2377
2378                /*
2379                 * Ensure that the modem control lines are de-activated.
2380                 * keep the DTR setting that is set in uart_set_options()
2381                 * We probably don't need a spinlock around this, but
2382                 */
2383                spin_lock_irqsave(&port->lock, flags);
2384                port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2385                spin_unlock_irqrestore(&port->lock, flags);
2386
2387                /*
2388                 * If this driver supports console, and it hasn't been
2389                 * successfully registered yet, try to re-register it.
2390                 * It may be that the port was not available.
2391                 */
2392                if (port->cons && !(port->cons->flags & CON_ENABLED))
2393                        register_console(port->cons);
2394
2395                /*
2396                 * Power down all ports by default, except the
2397                 * console if we have one.
2398                 */
2399                if (!uart_console(port))
2400                        uart_change_pm(state, UART_PM_STATE_OFF);
2401        }
2402}
2403
2404#ifdef CONFIG_CONSOLE_POLL
2405
2406static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2407{
2408        struct uart_driver *drv = driver->driver_state;
2409        struct uart_state *state = drv->state + line;
2410        struct tty_port *tport;
2411        struct uart_port *port;
2412        int baud = 9600;
2413        int bits = 8;
2414        int parity = 'n';
2415        int flow = 'n';
2416        int ret = 0;
2417
2418        tport = &state->port;
2419        mutex_lock(&tport->mutex);
2420
2421        port = uart_port_check(state);
2422        if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2423                ret = -1;
2424                goto out;
2425        }
2426
2427        if (port->ops->poll_init) {
2428                /*
2429                 * We don't set initialized as we only initialized the hw,
2430                 * e.g. state->xmit is still uninitialized.
2431                 */
2432                if (!tty_port_initialized(tport))
2433                        ret = port->ops->poll_init(port);
2434        }
2435
2436        if (!ret && options) {
2437                uart_parse_options(options, &baud, &parity, &bits, &flow);
2438                ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2439        }
2440out:
2441        mutex_unlock(&tport->mutex);
2442        return ret;
2443}
2444
2445static int uart_poll_get_char(struct tty_driver *driver, int line)
2446{
2447        struct uart_driver *drv = driver->driver_state;
2448        struct uart_state *state = drv->state + line;
2449        struct uart_port *port;
2450        int ret = -1;
2451
2452        port = uart_port_ref(state);
2453        if (port) {
2454                ret = port->ops->poll_get_char(port);
2455                uart_port_deref(port);
2456        }
2457
2458        return ret;
2459}
2460
2461static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2462{
2463        struct uart_driver *drv = driver->driver_state;
2464        struct uart_state *state = drv->state + line;
2465        struct uart_port *port;
2466
2467        port = uart_port_ref(state);
2468        if (!port)
2469                return;
2470
2471        if (ch == '\n')
2472                port->ops->poll_put_char(port, '\r');
2473        port->ops->poll_put_char(port, ch);
2474        uart_port_deref(port);
2475}
2476#endif
2477
2478static const struct tty_operations uart_ops = {
2479        .install        = uart_install,
2480        .open           = uart_open,
2481        .close          = uart_close,
2482        .write          = uart_write,
2483        .put_char       = uart_put_char,
2484        .flush_chars    = uart_flush_chars,
2485        .write_room     = uart_write_room,
2486        .chars_in_buffer= uart_chars_in_buffer,
2487        .flush_buffer   = uart_flush_buffer,
2488        .ioctl          = uart_ioctl,
2489        .throttle       = uart_throttle,
2490        .unthrottle     = uart_unthrottle,
2491        .send_xchar     = uart_send_xchar,
2492        .set_termios    = uart_set_termios,
2493        .set_ldisc      = uart_set_ldisc,
2494        .stop           = uart_stop,
2495        .start          = uart_start,
2496        .hangup         = uart_hangup,
2497        .break_ctl      = uart_break_ctl,
2498        .wait_until_sent= uart_wait_until_sent,
2499#ifdef CONFIG_PROC_FS
2500        .proc_show      = uart_proc_show,
2501#endif
2502        .tiocmget       = uart_tiocmget,
2503        .tiocmset       = uart_tiocmset,
2504        .set_serial     = uart_set_info_user,
2505        .get_serial     = uart_get_info_user,
2506        .get_icount     = uart_get_icount,
2507#ifdef CONFIG_CONSOLE_POLL
2508        .poll_init      = uart_poll_init,
2509        .poll_get_char  = uart_poll_get_char,
2510        .poll_put_char  = uart_poll_put_char,
2511#endif
2512};
2513
2514static const struct tty_port_operations uart_port_ops = {
2515        .carrier_raised = uart_carrier_raised,
2516        .dtr_rts        = uart_dtr_rts,
2517        .activate       = uart_port_activate,
2518        .shutdown       = uart_tty_port_shutdown,
2519};
2520
2521/**
2522 *      uart_register_driver - register a driver with the uart core layer
2523 *      @drv: low level driver structure
2524 *
2525 *      Register a uart driver with the core driver.  We in turn register
2526 *      with the tty layer, and initialise the core driver per-port state.
2527 *
2528 *      We have a proc file in /proc/tty/driver which is named after the
2529 *      normal driver.
2530 *
2531 *      drv->port should be NULL, and the per-port structures should be
2532 *      registered using uart_add_one_port after this call has succeeded.
2533 */
2534int uart_register_driver(struct uart_driver *drv)
2535{
2536        struct tty_driver *normal;
2537        int i, retval = -ENOMEM;
2538
2539        BUG_ON(drv->state);
2540
2541        /*
2542         * Maybe we should be using a slab cache for this, especially if
2543         * we have a large number of ports to handle.
2544         */
2545        drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2546        if (!drv->state)
2547                goto out;
2548
2549        normal = alloc_tty_driver(drv->nr);
2550        if (!normal)
2551                goto out_kfree;
2552
2553        drv->tty_driver = normal;
2554
2555        normal->driver_name     = drv->driver_name;
2556        normal->name            = drv->dev_name;
2557        normal->major           = drv->major;
2558        normal->minor_start     = drv->minor;
2559        normal->type            = TTY_DRIVER_TYPE_SERIAL;
2560        normal->subtype         = SERIAL_TYPE_NORMAL;
2561        normal->init_termios    = tty_std_termios;
2562        normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2563        normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2564        normal->flags           = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2565        normal->driver_state    = drv;
2566        tty_set_operations(normal, &uart_ops);
2567
2568        /*
2569         * Initialise the UART state(s).
2570         */
2571        for (i = 0; i < drv->nr; i++) {
2572                struct uart_state *state = drv->state + i;
2573                struct tty_port *port = &state->port;
2574
2575                tty_port_init(port);
2576                port->ops = &uart_port_ops;
2577        }
2578
2579        retval = tty_register_driver(normal);
2580        if (retval >= 0)
2581                return retval;
2582
2583        for (i = 0; i < drv->nr; i++)
2584                tty_port_destroy(&drv->state[i].port);
2585        put_tty_driver(normal);
2586out_kfree:
2587        kfree(drv->state);
2588out:
2589        return retval;
2590}
2591
2592/**
2593 *      uart_unregister_driver - remove a driver from the uart core layer
2594 *      @drv: low level driver structure
2595 *
2596 *      Remove all references to a driver from the core driver.  The low
2597 *      level driver must have removed all its ports via the
2598 *      uart_remove_one_port() if it registered them with uart_add_one_port().
2599 *      (ie, drv->port == NULL)
2600 */
2601void uart_unregister_driver(struct uart_driver *drv)
2602{
2603        struct tty_driver *p = drv->tty_driver;
2604        unsigned int i;
2605
2606        tty_unregister_driver(p);
2607        put_tty_driver(p);
2608        for (i = 0; i < drv->nr; i++)
2609                tty_port_destroy(&drv->state[i].port);
2610        kfree(drv->state);
2611        drv->state = NULL;
2612        drv->tty_driver = NULL;
2613}
2614
2615struct tty_driver *uart_console_device(struct console *co, int *index)
2616{
2617        struct uart_driver *p = co->data;
2618        *index = co->index;
2619        return p->tty_driver;
2620}
2621EXPORT_SYMBOL_GPL(uart_console_device);
2622
2623static ssize_t uartclk_show(struct device *dev,
2624        struct device_attribute *attr, char *buf)
2625{
2626        struct serial_struct tmp;
2627        struct tty_port *port = dev_get_drvdata(dev);
2628
2629        uart_get_info(port, &tmp);
2630        return sprintf(buf, "%d\n", tmp.baud_base * 16);
2631}
2632
2633static ssize_t type_show(struct device *dev,
2634        struct device_attribute *attr, char *buf)
2635{
2636        struct serial_struct tmp;
2637        struct tty_port *port = dev_get_drvdata(dev);
2638
2639        uart_get_info(port, &tmp);
2640        return sprintf(buf, "%d\n", tmp.type);
2641}
2642
2643static ssize_t line_show(struct device *dev,
2644        struct device_attribute *attr, char *buf)
2645{
2646        struct serial_struct tmp;
2647        struct tty_port *port = dev_get_drvdata(dev);
2648
2649        uart_get_info(port, &tmp);
2650        return sprintf(buf, "%d\n", tmp.line);
2651}
2652
2653static ssize_t port_show(struct device *dev,
2654        struct device_attribute *attr, char *buf)
2655{
2656        struct serial_struct tmp;
2657        struct tty_port *port = dev_get_drvdata(dev);
2658        unsigned long ioaddr;
2659
2660        uart_get_info(port, &tmp);
2661        ioaddr = tmp.port;
2662        if (HIGH_BITS_OFFSET)
2663                ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2664        return sprintf(buf, "0x%lX\n", ioaddr);
2665}
2666
2667static ssize_t irq_show(struct device *dev,
2668        struct device_attribute *attr, char *buf)
2669{
2670        struct serial_struct tmp;
2671        struct tty_port *port = dev_get_drvdata(dev);
2672
2673        uart_get_info(port, &tmp);
2674        return sprintf(buf, "%d\n", tmp.irq);
2675}
2676
2677static ssize_t flags_show(struct device *dev,
2678        struct device_attribute *attr, char *buf)
2679{
2680        struct serial_struct tmp;
2681        struct tty_port *port = dev_get_drvdata(dev);
2682
2683        uart_get_info(port, &tmp);
2684        return sprintf(buf, "0x%X\n", tmp.flags);
2685}
2686
2687static ssize_t xmit_fifo_size_show(struct device *dev,
2688        struct device_attribute *attr, char *buf)
2689{
2690        struct serial_struct tmp;
2691        struct tty_port *port = dev_get_drvdata(dev);
2692
2693        uart_get_info(port, &tmp);
2694        return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2695}
2696
2697static ssize_t close_delay_show(struct device *dev,
2698        struct device_attribute *attr, char *buf)
2699{
2700        struct serial_struct tmp;
2701        struct tty_port *port = dev_get_drvdata(dev);
2702
2703        uart_get_info(port, &tmp);
2704        return sprintf(buf, "%d\n", tmp.close_delay);
2705}
2706
2707static ssize_t closing_wait_show(struct device *dev,
2708        struct device_attribute *attr, char *buf)
2709{
2710        struct serial_struct tmp;
2711        struct tty_port *port = dev_get_drvdata(dev);
2712
2713        uart_get_info(port, &tmp);
2714        return sprintf(buf, "%d\n", tmp.closing_wait);
2715}
2716
2717static ssize_t custom_divisor_show(struct device *dev,
2718        struct device_attribute *attr, char *buf)
2719{
2720        struct serial_struct tmp;
2721        struct tty_port *port = dev_get_drvdata(dev);
2722
2723        uart_get_info(port, &tmp);
2724        return sprintf(buf, "%d\n", tmp.custom_divisor);
2725}
2726
2727static ssize_t io_type_show(struct device *dev,
2728        struct device_attribute *attr, char *buf)
2729{
2730        struct serial_struct tmp;
2731        struct tty_port *port = dev_get_drvdata(dev);
2732
2733        uart_get_info(port, &tmp);
2734        return sprintf(buf, "%d\n", tmp.io_type);
2735}
2736
2737static ssize_t iomem_base_show(struct device *dev,
2738        struct device_attribute *attr, char *buf)
2739{
2740        struct serial_struct tmp;
2741        struct tty_port *port = dev_get_drvdata(dev);
2742
2743        uart_get_info(port, &tmp);
2744        return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2745}
2746
2747static ssize_t iomem_reg_shift_show(struct device *dev,
2748        struct device_attribute *attr, char *buf)
2749{
2750        struct serial_struct tmp;
2751        struct tty_port *port = dev_get_drvdata(dev);
2752
2753        uart_get_info(port, &tmp);
2754        return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2755}
2756
2757static ssize_t console_show(struct device *dev,
2758        struct device_attribute *attr, char *buf)
2759{
2760        struct tty_port *port = dev_get_drvdata(dev);
2761        struct uart_state *state = container_of(port, struct uart_state, port);
2762        struct uart_port *uport;
2763        bool console = false;
2764
2765        mutex_lock(&port->mutex);
2766        uport = uart_port_check(state);
2767        if (uport)
2768                console = uart_console_enabled(uport);
2769        mutex_unlock(&port->mutex);
2770
2771        return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2772}
2773
2774static ssize_t console_store(struct device *dev,
2775        struct device_attribute *attr, const char *buf, size_t count)
2776{
2777        struct tty_port *port = dev_get_drvdata(dev);
2778        struct uart_state *state = container_of(port, struct uart_state, port);
2779        struct uart_port *uport;
2780        bool oldconsole, newconsole;
2781        int ret;
2782
2783        ret = kstrtobool(buf, &newconsole);
2784        if (ret)
2785                return ret;
2786
2787        mutex_lock(&port->mutex);
2788        uport = uart_port_check(state);
2789        if (uport) {
2790                oldconsole = uart_console_enabled(uport);
2791                if (oldconsole && !newconsole) {
2792                        ret = unregister_console(uport->cons);
2793                } else if (!oldconsole && newconsole) {
2794                        if (uart_console(uport)) {
2795                                uport->console_reinit = 1;
2796                                register_console(uport->cons);
2797                        } else {
2798                                ret = -ENOENT;
2799                        }
2800                }
2801        } else {
2802                ret = -ENXIO;
2803        }
2804        mutex_unlock(&port->mutex);
2805
2806        return ret < 0 ? ret : count;
2807}
2808
2809static DEVICE_ATTR_RO(uartclk);
2810static DEVICE_ATTR_RO(type);
2811static DEVICE_ATTR_RO(line);
2812static DEVICE_ATTR_RO(port);
2813static DEVICE_ATTR_RO(irq);
2814static DEVICE_ATTR_RO(flags);
2815static DEVICE_ATTR_RO(xmit_fifo_size);
2816static DEVICE_ATTR_RO(close_delay);
2817static DEVICE_ATTR_RO(closing_wait);
2818static DEVICE_ATTR_RO(custom_divisor);
2819static DEVICE_ATTR_RO(io_type);
2820static DEVICE_ATTR_RO(iomem_base);
2821static DEVICE_ATTR_RO(iomem_reg_shift);
2822static DEVICE_ATTR_RW(console);
2823
2824static struct attribute *tty_dev_attrs[] = {
2825        &dev_attr_uartclk.attr,
2826        &dev_attr_type.attr,
2827        &dev_attr_line.attr,
2828        &dev_attr_port.attr,
2829        &dev_attr_irq.attr,
2830        &dev_attr_flags.attr,
2831        &dev_attr_xmit_fifo_size.attr,
2832        &dev_attr_close_delay.attr,
2833        &dev_attr_closing_wait.attr,
2834        &dev_attr_custom_divisor.attr,
2835        &dev_attr_io_type.attr,
2836        &dev_attr_iomem_base.attr,
2837        &dev_attr_iomem_reg_shift.attr,
2838        &dev_attr_console.attr,
2839        NULL
2840};
2841
2842static const struct attribute_group tty_dev_attr_group = {
2843        .attrs = tty_dev_attrs,
2844};
2845
2846/**
2847 *      uart_add_one_port - attach a driver-defined port structure
2848 *      @drv: pointer to the uart low level driver structure for this port
2849 *      @uport: uart port structure to use for this port.
2850 *
2851 *      Context: task context, might sleep
2852 *
2853 *      This allows the driver to register its own uart_port structure
2854 *      with the core driver.  The main purpose is to allow the low
2855 *      level uart drivers to expand uart_port, rather than having yet
2856 *      more levels of structures.
2857 */
2858int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2859{
2860        struct uart_state *state;
2861        struct tty_port *port;
2862        int ret = 0;
2863        struct device *tty_dev;
2864        int num_groups;
2865
2866        if (uport->line >= drv->nr)
2867                return -EINVAL;
2868
2869        state = drv->state + uport->line;
2870        port = &state->port;
2871
2872        mutex_lock(&port_mutex);
2873        mutex_lock(&port->mutex);
2874        if (state->uart_port) {
2875                ret = -EINVAL;
2876                goto out;
2877        }
2878
2879        /* Link the port to the driver state table and vice versa */
2880        atomic_set(&state->refcount, 1);
2881        init_waitqueue_head(&state->remove_wait);
2882        state->uart_port = uport;
2883        uport->state = state;
2884
2885        state->pm_state = UART_PM_STATE_UNDEFINED;
2886        uport->cons = drv->cons;
2887        uport->minor = drv->tty_driver->minor_start + uport->line;
2888        uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2889                                drv->tty_driver->name_base + uport->line);
2890        if (!uport->name) {
2891                ret = -ENOMEM;
2892                goto out;
2893        }
2894
2895        /*
2896         * If this port is in use as a console then the spinlock is already
2897         * initialised.
2898         */
2899        if (!uart_console_enabled(uport))
2900                uart_port_spin_lock_init(uport);
2901
2902        if (uport->cons && uport->dev)
2903                of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2904
2905        tty_port_link_device(port, drv->tty_driver, uport->line);
2906        uart_configure_port(drv, state, uport);
2907
2908        port->console = uart_console(uport);
2909
2910        num_groups = 2;
2911        if (uport->attr_group)
2912                num_groups++;
2913
2914        uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2915                                    GFP_KERNEL);
2916        if (!uport->tty_groups) {
2917                ret = -ENOMEM;
2918                goto out;
2919        }
2920        uport->tty_groups[0] = &tty_dev_attr_group;
2921        if (uport->attr_group)
2922                uport->tty_groups[1] = uport->attr_group;
2923
2924        /*
2925         * Register the port whether it's detected or not.  This allows
2926         * setserial to be used to alter this port's parameters.
2927         */
2928        tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2929                        uport->line, uport->dev, port, uport->tty_groups);
2930        if (!IS_ERR(tty_dev)) {
2931                device_set_wakeup_capable(tty_dev, 1);
2932        } else {
2933                dev_err(uport->dev, "Cannot register tty device on line %d\n",
2934                       uport->line);
2935        }
2936
2937        /*
2938         * Ensure UPF_DEAD is not set.
2939         */
2940        uport->flags &= ~UPF_DEAD;
2941
2942 out:
2943        mutex_unlock(&port->mutex);
2944        mutex_unlock(&port_mutex);
2945
2946        return ret;
2947}
2948
2949/**
2950 *      uart_remove_one_port - detach a driver defined port structure
2951 *      @drv: pointer to the uart low level driver structure for this port
2952 *      @uport: uart port structure for this port
2953 *
2954 *      Context: task context, might sleep
2955 *
2956 *      This unhooks (and hangs up) the specified port structure from the
2957 *      core driver.  No further calls will be made to the low-level code
2958 *      for this port.
2959 */
2960int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2961{
2962        struct uart_state *state = drv->state + uport->line;
2963        struct tty_port *port = &state->port;
2964        struct uart_port *uart_port;
2965        struct tty_struct *tty;
2966        int ret = 0;
2967
2968        mutex_lock(&port_mutex);
2969
2970        /*
2971         * Mark the port "dead" - this prevents any opens from
2972         * succeeding while we shut down the port.
2973         */
2974        mutex_lock(&port->mutex);
2975        uart_port = uart_port_check(state);
2976        if (uart_port != uport)
2977                dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2978                          uart_port, uport);
2979
2980        if (!uart_port) {
2981                mutex_unlock(&port->mutex);
2982                ret = -EINVAL;
2983                goto out;
2984        }
2985        uport->flags |= UPF_DEAD;
2986        mutex_unlock(&port->mutex);
2987
2988        /*
2989         * Remove the devices from the tty layer
2990         */
2991        tty_port_unregister_device(port, drv->tty_driver, uport->line);
2992
2993        tty = tty_port_tty_get(port);
2994        if (tty) {
2995                tty_vhangup(port->tty);
2996                tty_kref_put(tty);
2997        }
2998
2999        /*
3000         * If the port is used as a console, unregister it
3001         */
3002        if (uart_console(uport))
3003                unregister_console(uport->cons);
3004
3005        /*
3006         * Free the port IO and memory resources, if any.
3007         */
3008        if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3009                uport->ops->release_port(uport);
3010        kfree(uport->tty_groups);
3011        kfree(uport->name);
3012
3013        /*
3014         * Indicate that there isn't a port here anymore.
3015         */
3016        uport->type = PORT_UNKNOWN;
3017
3018        mutex_lock(&port->mutex);
3019        WARN_ON(atomic_dec_return(&state->refcount) < 0);
3020        wait_event(state->remove_wait, !atomic_read(&state->refcount));
3021        state->uart_port = NULL;
3022        mutex_unlock(&port->mutex);
3023out:
3024        mutex_unlock(&port_mutex);
3025
3026        return ret;
3027}
3028
3029/*
3030 *      Are the two ports equivalent?
3031 */
3032int uart_match_port(struct uart_port *port1, struct uart_port *port2)
3033{
3034        if (port1->iotype != port2->iotype)
3035                return 0;
3036
3037        switch (port1->iotype) {
3038        case UPIO_PORT:
3039                return (port1->iobase == port2->iobase);
3040        case UPIO_HUB6:
3041                return (port1->iobase == port2->iobase) &&
3042                       (port1->hub6   == port2->hub6);
3043        case UPIO_MEM:
3044        case UPIO_MEM16:
3045        case UPIO_MEM32:
3046        case UPIO_MEM32BE:
3047        case UPIO_AU:
3048        case UPIO_TSI:
3049                return (port1->mapbase == port2->mapbase);
3050        }
3051        return 0;
3052}
3053EXPORT_SYMBOL(uart_match_port);
3054
3055/**
3056 *      uart_handle_dcd_change - handle a change of carrier detect state
3057 *      @uport: uart_port structure for the open port
3058 *      @status: new carrier detect status, nonzero if active
3059 *
3060 *      Caller must hold uport->lock
3061 */
3062void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3063{
3064        struct tty_port *port = &uport->state->port;
3065        struct tty_struct *tty = port->tty;
3066        struct tty_ldisc *ld;
3067
3068        lockdep_assert_held_once(&uport->lock);
3069
3070        if (tty) {
3071                ld = tty_ldisc_ref(tty);
3072                if (ld) {
3073                        if (ld->ops->dcd_change)
3074                                ld->ops->dcd_change(tty, status);
3075                        tty_ldisc_deref(ld);
3076                }
3077        }
3078
3079        uport->icount.dcd++;
3080
3081        if (uart_dcd_enabled(uport)) {
3082                if (status)
3083                        wake_up_interruptible(&port->open_wait);
3084                else if (tty)
3085                        tty_hangup(tty);
3086        }
3087}
3088EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3089
3090/**
3091 *      uart_handle_cts_change - handle a change of clear-to-send state
3092 *      @uport: uart_port structure for the open port
3093 *      @status: new clear to send status, nonzero if active
3094 *
3095 *      Caller must hold uport->lock
3096 */
3097void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3098{
3099        lockdep_assert_held_once(&uport->lock);
3100
3101        uport->icount.cts++;
3102
3103        if (uart_softcts_mode(uport)) {
3104                if (uport->hw_stopped) {
3105                        if (status) {
3106                                uport->hw_stopped = 0;
3107                                uport->ops->start_tx(uport);
3108                                uart_write_wakeup(uport);
3109                        }
3110                } else {
3111                        if (!status) {
3112                                uport->hw_stopped = 1;
3113                                uport->ops->stop_tx(uport);
3114                        }
3115                }
3116
3117        }
3118}
3119EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3120
3121/**
3122 * uart_insert_char - push a char to the uart layer
3123 *
3124 * User is responsible to call tty_flip_buffer_push when they are done with
3125 * insertion.
3126 *
3127 * @port: corresponding port
3128 * @status: state of the serial port RX buffer (LSR for 8250)
3129 * @overrun: mask of overrun bits in @status
3130 * @ch: character to push
3131 * @flag: flag for the character (see TTY_NORMAL and friends)
3132 */
3133void uart_insert_char(struct uart_port *port, unsigned int status,
3134                 unsigned int overrun, unsigned int ch, unsigned int flag)
3135{
3136        struct tty_port *tport = &port->state->port;
3137
3138        if ((status & port->ignore_status_mask & ~overrun) == 0)
3139                if (tty_insert_flip_char(tport, ch, flag) == 0)
3140                        ++port->icount.buf_overrun;
3141
3142        /*
3143         * Overrun is special.  Since it's reported immediately,
3144         * it doesn't affect the current character.
3145         */
3146        if (status & ~port->ignore_status_mask & overrun)
3147                if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3148                        ++port->icount.buf_overrun;
3149}
3150EXPORT_SYMBOL_GPL(uart_insert_char);
3151
3152#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3153static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3154
3155static void uart_sysrq_on(struct work_struct *w)
3156{
3157        int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3158
3159        sysrq_toggle_support(1);
3160        pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3161                sysrq_toggle_seq_len, sysrq_toggle_seq);
3162}
3163static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3164
3165/**
3166 *      uart_try_toggle_sysrq - Enables SysRq from serial line
3167 *      @port: uart_port structure where char(s) after BREAK met
3168 *      @ch: new character in the sequence after received BREAK
3169 *
3170 *      Enables magic SysRq when the required sequence is met on port
3171 *      (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3172 *
3173 *      Returns false if @ch is out of enabling sequence and should be
3174 *      handled some other way, true if @ch was consumed.
3175 */
3176bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3177{
3178        int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3179
3180        if (!sysrq_toggle_seq_len)
3181                return false;
3182
3183        BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3184        if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3185                port->sysrq_seq = 0;
3186                return false;
3187        }
3188
3189        if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3190                port->sysrq = jiffies + SYSRQ_TIMEOUT;
3191                return true;
3192        }
3193
3194        schedule_work(&sysrq_enable_work);
3195
3196        port->sysrq = 0;
3197        return true;
3198}
3199EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3200#endif
3201
3202EXPORT_SYMBOL(uart_write_wakeup);
3203EXPORT_SYMBOL(uart_register_driver);
3204EXPORT_SYMBOL(uart_unregister_driver);
3205EXPORT_SYMBOL(uart_suspend_port);
3206EXPORT_SYMBOL(uart_resume_port);
3207EXPORT_SYMBOL(uart_add_one_port);
3208EXPORT_SYMBOL(uart_remove_one_port);
3209
3210/**
3211 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3212 * @port: uart device's target port
3213 *
3214 * This function implements the device tree binding described in
3215 * Documentation/devicetree/bindings/serial/rs485.txt.
3216 */
3217int uart_get_rs485_mode(struct uart_port *port)
3218{
3219        struct serial_rs485 *rs485conf = &port->rs485;
3220        struct device *dev = port->dev;
3221        u32 rs485_delay[2];
3222        int ret;
3223
3224        ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3225                                             rs485_delay, 2);
3226        if (!ret) {
3227                rs485conf->delay_rts_before_send = rs485_delay[0];
3228                rs485conf->delay_rts_after_send = rs485_delay[1];
3229        } else {
3230                rs485conf->delay_rts_before_send = 0;
3231                rs485conf->delay_rts_after_send = 0;
3232        }
3233
3234        /*
3235         * Clear full-duplex and enabled flags, set RTS polarity to active high
3236         * to get to a defined state with the following properties:
3237         */
3238        rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3239                              SER_RS485_TERMINATE_BUS |
3240                              SER_RS485_RTS_AFTER_SEND);
3241        rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3242
3243        if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3244                rs485conf->flags |= SER_RS485_RX_DURING_TX;
3245
3246        if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3247                rs485conf->flags |= SER_RS485_ENABLED;
3248
3249        if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3250                rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3251                rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3252        }
3253
3254        /*
3255         * Disabling termination by default is the safe choice:  Else if many
3256         * bus participants enable it, no communication is possible at all.
3257         * Works fine for short cables and users may enable for longer cables.
3258         */
3259        port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3260                                                        GPIOD_OUT_LOW);
3261        if (IS_ERR(port->rs485_term_gpio)) {
3262                ret = PTR_ERR(port->rs485_term_gpio);
3263                port->rs485_term_gpio = NULL;
3264                return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3265        }
3266
3267        return 0;
3268}
3269EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3270
3271MODULE_DESCRIPTION("Serial driver core");
3272MODULE_LICENSE("GPL");
3273