serial_sicc.c

优龙2410linux2.6.8内核源代码

    struct SICC_info *info = tty->driver_data;

    return CIRC_CNT(info->xmit.head, info->xmit.tail, SICC_XMIT_SIZE);
}

static void siccuart_flush_buffer(struct tty_struct *tty)
{
    struct SICC_info *info = tty->driver_data;
    unsigned long flags;

    pr_debug("siccuart_flush_buffer(%d) called\n", tty->index);
    save_flags(flags); cli();
    info->xmit.head = info->xmit.tail = 0;
    restore_flags(flags);
    wake_up_interruptible(&tty->write_wait);
    if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
        tty->ldisc.write_wakeup)
        (tty->ldisc.write_wakeup)(tty);
}

/*
 * This function is used to send a high-priority XON/XOFF character to
 * the device
 */
static void siccuart_send_xchar(struct tty_struct *tty, char ch)
{
    struct SICC_info *info = tty->driver_data;

    info->x_char = ch;
    if (ch)
       siccuart_enable_tx_interrupt(info);
}

static void siccuart_throttle(struct tty_struct *tty)
{
    struct SICC_info *info = tty->driver_data;
    unsigned long flags;

    if (I_IXOFF(tty))
        siccuart_send_xchar(tty, STOP_CHAR(tty));

    if (tty->termios->c_cflag & CRTSCTS) {
        save_flags(flags); cli();
        info->mctrl &= ~TIOCM_RTS;
        info->port->set_mctrl(info->port, info->mctrl);
        restore_flags(flags);
    }
}

static void siccuart_unthrottle(struct tty_struct *tty)
{
    struct SICC_info *info = (struct SICC_info *) tty->driver_data;
    unsigned long flags;

    if (I_IXOFF(tty)) {
        if (info->x_char)
            info->x_char = 0;
        else
            siccuart_send_xchar(tty, START_CHAR(tty));
    }

    if (tty->termios->c_cflag & CRTSCTS) {
        save_flags(flags); cli();
        info->mctrl |= TIOCM_RTS;
        info->port->set_mctrl(info->port, info->mctrl);
        restore_flags(flags);
    }
}

static int get_serial_info(struct SICC_info *info, struct serial_struct *retinfo)
{
    struct SICC_state *state = info->state;
    struct SICC_port *port = info->port;
    struct serial_struct tmp;

    memset(&tmp, 0, sizeof(tmp));
    tmp.type       = 0;
    tmp.line       = state->line;
    tmp.port       = port->uart_base;
    if (HIGH_BITS_OFFSET)
        tmp.port_high = port->uart_base >> HIGH_BITS_OFFSET;
    tmp.irq        = port->irqrx;
    tmp.flags      = 0;
    tmp.xmit_fifo_size = port->fifosize;
    tmp.baud_base      = port->uartclk / 16;
    tmp.close_delay    = state->close_delay;
    tmp.closing_wait   = state->closing_wait;
    tmp.custom_divisor = state->custom_divisor;

    if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
        return -EFAULT;
    return 0;
}

static int set_serial_info(struct SICC_info *info,
               struct serial_struct *newinfo)
{
    struct serial_struct new_serial;
    struct SICC_state *state, old_state;
    struct SICC_port *port;
    unsigned long new_port;
    unsigned int i, change_irq, change_port;
    int retval = 0;

    if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
        return -EFAULT;

    state = info->state;
    old_state = *state;
    port = info->port;

    new_port = new_serial.port;
    if (HIGH_BITS_OFFSET)
        new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;

    change_irq  = new_serial.irq != port->irqrx;
    change_port = new_port != port->uart_base;

    if (!capable(CAP_SYS_ADMIN)) {
        if (change_irq || change_port ||
            (new_serial.baud_base != port->uartclk / 16) ||
            (new_serial.close_delay != state->close_delay) ||
            (new_serial.xmit_fifo_size != port->fifosize) ||
            ((new_serial.flags & ~ASYNC_USR_MASK) !=
             (state->flags & ~ASYNC_USR_MASK)))
            return -EPERM;
        state->flags = ((state->flags & ~ASYNC_USR_MASK) |
                (new_serial.flags & ASYNC_USR_MASK));
        info->flags = ((info->flags & ~ASYNC_USR_MASK) |
                   (new_serial.flags & ASYNC_USR_MASK));
        state->custom_divisor = new_serial.custom_divisor;
        goto check_and_exit;
    }

    if ((new_serial.irq >= NR_IRQS) || (new_serial.irq < 0) ||
        (new_serial.baud_base < 9600))
        return -EINVAL;

    if (new_serial.type && change_port) {
        for (i = 0; i < SERIAL_SICC_NR; i++)
            if ((port != sicc_ports + i) &&
                sicc_ports[i].uart_base != new_port)
                return -EADDRINUSE;
    }

    if ((change_port || change_irq) && (state->count > 1))
        return -EBUSY;

    /*
     * OK, past this point, all the error checking has been done.
     * At this point, we start making changes.....
     */
    port->uartclk = new_serial.baud_base * 16;
    state->flags = ((state->flags & ~ASYNC_FLAGS) |
            (new_serial.flags & ASYNC_FLAGS));
    info->flags = ((state->flags & ~ASYNC_INTERNAL_FLAGS) |
               (info->flags & ASYNC_INTERNAL_FLAGS));
    state->custom_divisor = new_serial.custom_divisor;
    state->close_delay = new_serial.close_delay * HZ / 100;
    state->closing_wait = new_serial.closing_wait * HZ / 100;
    info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
    port->fifosize = new_serial.xmit_fifo_size;

    if (change_port || change_irq) {
        /*
         * We need to shutdown the serial port at the old
         * port/irq combination.
         */
        siccuart_shutdown(info);
        port->irqrx = new_serial.irq;
        port->uart_base = new_port;
    }

check_and_exit:
    if (!port->uart_base)
        return 0;
    if (info->flags & ASYNC_INITIALIZED) {
        if ((old_state.flags & ASYNC_SPD_MASK) !=
            (state->flags & ASYNC_SPD_MASK) ||
            (old_state.custom_divisor != state->custom_divisor)) {
            if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
                info->tty->alt_speed = 57600;
            if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
                info->tty->alt_speed = 115200;
            if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
                info->tty->alt_speed = 230400;
            if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
                info->tty->alt_speed = 460800;
            siccuart_change_speed(info, NULL);
        }
    } else
        retval = siccuart_startup(info);
    return retval;
}


/*
 * get_lsr_info - get line status register info
 */
static int get_lsr_info(struct SICC_info *info, unsigned int *value)
{
    unsigned int result, status;
    unsigned long flags;

    save_flags(flags); cli();
    status = readb(info->port->uart_base +  BL_SICC_LSR);
    restore_flags(flags);
    result = status & _LSR_TSR_EMPTY ? TIOCSER_TEMT : 0;

    /*
     * If we're about to load something into the transmit
     * register, we'll pretend the transmitter isn't empty to
     * avoid a race condition (depending on when the transmit
     * interrupt happens).
     */
    if (info->x_char ||
        ((CIRC_CNT(info->xmit.head, info->xmit.tail,
               SICC_XMIT_SIZE) > 0) &&
         !info->tty->stopped && !info->tty->hw_stopped))
        result &= TIOCSER_TEMT;

    return put_user(result, value);
}

static int get_modem_info(struct SICC_info *info, unsigned int *value)
{
    unsigned int result = info->mctrl;

    return put_user(result, value);
}

static int set_modem_info(struct SICC_info *info, unsigned int cmd,
              unsigned int *value)
{
    unsigned int arg, old;
    unsigned long flags;

    if (get_user(arg, value))
        return -EFAULT;

    old = info->mctrl;
    switch (cmd) {
    case TIOCMBIS:
        info->mctrl |= arg;
        break;

    case TIOCMBIC:
        info->mctrl &= ~arg;
        break;

    case TIOCMSET:
        info->mctrl = arg;
        break;

    default:
        return -EINVAL;
    }
    save_flags(flags); cli();
    if (old != info->mctrl)
        info->port->set_mctrl(info->port, info->mctrl);
    restore_flags(flags);
    return 0;
}

static void siccuart_break_ctl(struct tty_struct *tty, int break_state)
{
    struct SICC_info *info = tty->driver_data;
    unsigned long flags;
    unsigned int lcr_h;


    save_flags(flags); cli();
    lcr_h = readb(info->port + BL_SICC_LSR);
    if (break_state == -1)
        lcr_h |=  _LSR_LB_MASK;
    else
        lcr_h &= ~_LSR_LB_MASK;
    writeb(lcr_h, info->port + BL_SICC_LSRS);
    restore_flags(flags);
}

static int siccuart_ioctl(struct tty_struct *tty, struct file *file,
               unsigned int cmd, unsigned long arg)
{
    struct SICC_info *info = tty->driver_data;
    struct SICC_icount cnow;
    struct serial_icounter_struct icount;
    unsigned long flags;

    if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
        (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
        (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
        if (tty->flags & (1 << TTY_IO_ERROR))
            return -EIO;
    }

    switch (cmd) {
        case TIOCMGET:
            return get_modem_info(info, (unsigned int *)arg);
        case TIOCMBIS:
        case TIOCMBIC:
        case TIOCMSET:
            return set_modem_info(info, cmd, (unsigned int *)arg);
        case TIOCGSERIAL:
            return get_serial_info(info,
                           (struct serial_struct *)arg);
        case TIOCSSERIAL:
            return set_serial_info(info,
                           (struct serial_struct *)arg);
        case TIOCSERGETLSR: /* Get line status register */
            return get_lsr_info(info, (unsigned int *)arg);
        /*
         * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
         * - mask passed in arg for lines of interest
         *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
         * Caller should use TIOCGICOUNT to see which one it was
         */
        case TIOCMIWAIT:
            return 0;
        /*
         * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
         * Return: write counters to the user passed counter struct
         * NB: both 1->0 and 0->1 transitions are counted except for
         *     RI where only 0->1 is counted.
         */
        case TIOCGICOUNT:
            save_flags(flags); cli();
            cnow = info->state->icount;
            restore_flags(flags);
            icount.cts = cnow.cts;
            icount.dsr = cnow.dsr;
            icount.rng = cnow.rng;
            icount.dcd = cnow.dcd;
            icount.rx  = cnow.rx;
            icount.tx  = cnow.tx;
            icount.frame = cnow.frame;
            icount.overrun = cnow.overrun;
            icount.parity = cnow.parity;
            icount.brk = cnow.brk;
            icount.buf_overrun = cnow.buf_overrun;

            return copy_to_user((void *)arg, &icount, sizeof(icount))
                    ? -EFAULT : 0;

        default:
            return -ENOIOCTLCMD;
    }
    return 0;
}

static void siccuart_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
    struct SICC_info *info = tty->driver_data;
    unsigned long flags;
    unsigned int cflag = tty->termios->c_cflag;

    if ((cflag ^ old_termios->c_cflag) == 0 &&
        RELEVENT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
        return;

    siccuart_change_speed(info, old_termios);

    /* Handle transition to B0 status */
    if ((old_termios->c_cflag & CBAUD) &&
        !(cflag & CBAUD)) {
        save_flags(flags); cli();
        info->mctrl &= ~(TIOCM_RTS | TIOCM_DTR);
        info->port->set_mctrl(info->port, info->mctrl);
        restore_flags(flags);
    }

    /* Handle transition away from B0 status */
    if (!(old_termios->c_cflag & CBAUD) &&
        (cflag & CBAUD)) {
        save_flags(flags); cli();
        info->mctrl |= TIOCM_DTR;
        if (!(cflag & CRTSCTS) ||
            !test_bit(TTY_THROTTLED, &tty->flags))
            info->mctrl |= TIOCM_RTS;
        info->port->set_mctrl(info->port, info->mctrl);
        restore_flags(flags);
    }

    /* Handle turning off CRTSCTS */
    if ((old_termios->c_cflag & CRTSCTS) &&
        !(cflag & CRTSCTS)) {
        tty->hw_stopped = 0;
        siccuart_start(tty);
    }

#if 0
    /*
     * No need to wake up processes in open wait, since they
     * sample the CLOCAL flag once, and don't recheck it.
     * XXX  It's not clear whether the current behavior is correct
     * or not.  Hence, this may change.....
     */
    if (!(old_termios->c_cflag & CLOCAL) &&
        (tty->termios->c_cflag & CLOCAL))
        wake_up_interruptible(&info->open_wait);
#endif
}

static void siccuart_close(struct tty_struct *tty, struct file *filp)
{
    struct SICC_info *info = tty->driver_data;
    struct SICC_state *state;
    unsigned long flags;

    if (!info)
        return;

    state = info->state;

    //pr_debug("siccuart_close() called\n");

    save_flags(flags); cli();

    if (tty_hung_up_p(filp)) {
        restore_flags(flags);
        return;
    }

    if ((tty->count == 1) && (state->count != 1)) {
        /*
         * Uh, oh.  tty->count is 1, which means that the tty
         * structure will be freed.  state->count should always
         * be one in these conditions.  If it's greater than
         * one, we've got real problems, since it means the
         * serial port won't be shutdown.
         */
        printk("siccuart_close: bad serial port count; tty->count is 1, state->count is %d\n", state->count);
        state->count = 1;
    }
    if (--state->count < 0) {
        printk("rs_close: bad serial port count for %s: %d\n", tty->name, state->count);
        state->count = 0;
    }
    if (state->count) {
        restore_flags(flags);
        return;
    }
    info->flags |= ASYNC_CLOSING;
    restore_flags(flags);
    /*
     * Now we wait for the transmit buffer to clear; and we notify
     * the line discipline to only process XON/XOFF characters.
     */
    tty->closing = 1;
    if (info->state->closing_wait != ASYNC_CLOSING_WAIT_NONE)
        tty_wait_until_sent(tty, info->state->closing_wait);
    /*
     * At this point, we stop accepting input.  To do this, we
     * disable the receive line status interrupts.
     */
    if (info->flags & ASYNC_INITIALIZED) {
        siccuart_disable_rx_interrupt(info);
        /*
         * Before we drop DTR, make sure the UART transmitter
         * has completely drained; this is especially
         * important if there is a transmit FIFO!
         */
        siccuart_wait_until_sent(tty, info->timeout);
    }
    siccuart_shutdown(info);
    if (tty->driver->flush_buffer)
        tty->driver->flush_buffer(tty);
    if (tty->ldisc.flush_buffer)
        tty->ldisc.flush_buffer(tty);
    tty->closing = 0;
    info->event = 0;
    info->tty = NULL;
    if (info->blocked_open) {
        if (info->state->close_delay) {
            set_current_state(TASK_INTERRUPTIBLE);
            schedule_timeout(info->state->close_delay);
        }
        wake_up_interruptible(&info->open_wait);
    }
    info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
    wake_up_interruptible(&info->close_wait);
}

static void siccuart_wait_until_sent(struct tty_struct *tty, int timeout)
{
    struct SICC_info *info = (struct SICC_info *) tty->driver_data;
    unsigned long char_time, expire;

    if (info->port->fifosize == 0)
        return;

    /*
     * Set the check interval to be 1/5 of the estimated time to
     * send a single character, and make it at least 1.  The check
     * interval should also be less than the timeout.
     *
     * Note: we have to use pretty tight timings here to satisfy
     * the NIST-PCTS.
     */
    char_time = (info->timeout - HZ/50) / info->port->fifosize;
    char_time = char_time / 5;
    if (char_time == 0)
        char_time = 1;

    // Crazy!!   sometimes the input arg 'timeout' can be negtive numbers  :-(
    if (timeout >= 0 && timeout < char_time)
        char_time = timeout;