dz.c

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/*
 * dz.c: Serial port driver for DECstations equipped
 *       with the DZ chipset.
 *
 * Copyright (C) 1998 Olivier A. D. Lebaillif
 *
 * Email: [email protected]
 *
 * Copyright (C) 2004, 2006, 2007  Maciej W. Rozycki
 *
 * [31-AUG-98] triemer
 * Changed IRQ to use Harald's dec internals interrupts.h
 * removed base_addr code - moving address assignment to setup.c
 * Changed name of dz_init to rs_init to be consistent with tc code
 * [13-NOV-98] triemer fixed code to receive characters
 *    after patches by harald to irq code.
 * [09-JAN-99] triemer minor fix for schedule - due to removal of timeout
 *            field from "current" - somewhere between 2.1.121 and 2.1.131
 Qua Jun 27 15:02:26 BRT 2001
 * [27-JUN-2001] Arnaldo Carvalho de Melo <[email protected]> - cleanups
 *
 * Parts (C) 1999 David Airlie, [email protected]
 * [07-SEP-99] Bugfixes
 *
 * [06-Jan-2002] Russell King <[email protected]>
 * Converted to new serial core
 */

#undef DEBUG_DZ

#if defined(CONFIG_SERIAL_DZ_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/module.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/sysrq.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>

#include <linux/atomic.h>
#include <asm/bootinfo.h>
#include <asm/io.h>

#include <asm/dec/interrupts.h>
#include <asm/dec/kn01.h>
#include <asm/dec/kn02.h>
#include <asm/dec/machtype.h>
#include <asm/dec/prom.h>
#include <asm/dec/system.h>

#include "dz.h"


MODULE_DESCRIPTION("DECstation DZ serial driver");
MODULE_LICENSE("GPL");


static char dz_name[] __initdata = "DECstation DZ serial driver version ";
static char dz_version[] __initdata = "1.04";

struct dz_port {
    struct dz_mux       *mux;
    struct uart_port    port;
    unsigned int        cflag;
};

struct dz_mux {
    struct dz_port      dport[DZ_NB_PORT];
    atomic_t        map_guard;
    atomic_t        irq_guard;
    int         initialised;
};

static struct dz_mux dz_mux;

static inline struct dz_port *to_dport(struct uart_port *uport)
{
    return container_of(uport, struct dz_port, port);
}

/*
 * ------------------------------------------------------------
 * dz_in () and dz_out ()
 *
 * These routines are used to access the registers of the DZ
 * chip, hiding relocation differences between implementation.
 * ------------------------------------------------------------
 */

static u16 dz_in(struct dz_port *dport, unsigned offset)
{
    void __iomem *addr = dport->port.membase + offset;

    return readw(addr);
}

static void dz_out(struct dz_port *dport, unsigned offset, u16 value)
{
    void __iomem *addr = dport->port.membase + offset;

    writew(value, addr);
}

/*
 * ------------------------------------------------------------
 * rs_stop () and rs_start ()
 *
 * These routines are called before setting or resetting
 * tty->stopped. They enable or disable transmitter interrupts,
 * as necessary.
 * ------------------------------------------------------------
 */

static void dz_stop_tx(struct uart_port *uport)
{
    struct dz_port *dport = to_dport(uport);
    u16 tmp, mask = 1 << dport->port.line;

    tmp = dz_in(dport, DZ_TCR); /* read the TX flag */
    tmp &= ~mask;           /* clear the TX flag */
    dz_out(dport, DZ_TCR, tmp);
}

static void dz_start_tx(struct uart_port *uport)
{
    struct dz_port *dport = to_dport(uport);
    u16 tmp, mask = 1 << dport->port.line;

    tmp = dz_in(dport, DZ_TCR); /* read the TX flag */
    tmp |= mask;            /* set the TX flag */
    dz_out(dport, DZ_TCR, tmp);
}

static void dz_stop_rx(struct uart_port *uport)
{
    struct dz_port *dport = to_dport(uport);

    dport->cflag &= ~DZ_RXENAB;
    dz_out(dport, DZ_LPR, dport->cflag);
}

static void dz_enable_ms(struct uart_port *uport)
{
    /* nothing to do */
}

/*
 * ------------------------------------------------------------
 *
 * Here start the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * dz_interrupt.  They were separated out for readability's sake.
 *
 * Note: dz_interrupt() is a "fast" interrupt, which means that it
 * runs with interrupts turned off.  People who may want to modify
 * dz_interrupt() should try to keep the interrupt handler as fast as
 * possible.  After you are done making modifications, it is not a bad
 * idea to do:
 *
 *  make drivers/serial/dz.s
 *
 * and look at the resulting assemble code in dz.s.
 *
 * ------------------------------------------------------------
 */

/*
 * ------------------------------------------------------------
 * receive_char ()
 *
 * This routine deals with inputs from any lines.
 * ------------------------------------------------------------
 */
static inline void dz_receive_chars(struct dz_mux *mux)
{
    struct uart_port *uport;
    struct dz_port *dport = &mux->dport[0];
    struct tty_struct *tty = NULL;
    struct uart_icount *icount;
    int lines_rx[DZ_NB_PORT] = { [0 ... DZ_NB_PORT - 1] = 0 };
    unsigned char ch, flag;
    u16 status;
    int i;

    while ((status = dz_in(dport, DZ_RBUF)) & DZ_DVAL) {
        dport = &mux->dport[LINE(status)];
        uport = &dport->port;
        tty = uport->state->port.tty;   /* point to the proper dev */

        ch = UCHAR(status);     /* grab the char */
        flag = TTY_NORMAL;

        icount = &uport->icount;
        icount->rx++;

        if (unlikely(status & (DZ_OERR | DZ_FERR | DZ_PERR))) {

            /*
             * There is no separate BREAK status bit, so treat
             * null characters with framing errors as BREAKs;
             * normally, otherwise.  For this move the Framing
             * Error bit to a simulated BREAK bit.
             */
            if (!ch) {
                status |= (status & DZ_FERR) >>
                      (ffs(DZ_FERR) - ffs(DZ_BREAK));
                status &= ~DZ_FERR;
            }

            /* Handle SysRq/SAK & keep track of the statistics. */
            if (status & DZ_BREAK) {
                icount->brk++;
                if (uart_handle_break(uport))
                    continue;
            } else if (status & DZ_FERR)
                icount->frame++;
            else if (status & DZ_PERR)
                icount->parity++;
            if (status & DZ_OERR)
                icount->overrun++;

            status &= uport->read_status_mask;
            if (status & DZ_BREAK)
                flag = TTY_BREAK;
            else if (status & DZ_FERR)
                flag = TTY_FRAME;
            else if (status & DZ_PERR)
                flag = TTY_PARITY;

        }

        if (uart_handle_sysrq_char(uport, ch))
            continue;

        uart_insert_char(uport, status, DZ_OERR, ch, flag);
        lines_rx[LINE(status)] = 1;
    }
    for (i = 0; i < DZ_NB_PORT; i++)
        if (lines_rx[i])
            tty_flip_buffer_push(mux->dport[i].port.state->port.tty);
}

/*
 * ------------------------------------------------------------
 * transmit_char ()
 *
 * This routine deals with outputs to any lines.
 * ------------------------------------------------------------
 */
static inline void dz_transmit_chars(struct dz_mux *mux)
{
    struct dz_port *dport = &mux->dport[0];
    struct circ_buf *xmit;
    unsigned char tmp;
    u16 status;

    status = dz_in(dport, DZ_CSR);
    dport = &mux->dport[LINE(status)];
    xmit = &dport->port.state->xmit;

    if (dport->port.x_char) {       /* XON/XOFF chars */
        dz_out(dport, DZ_TDR, dport->port.x_char);
        dport->port.icount.tx++;
        dport->port.x_char = 0;
        return;
    }
    /* If nothing to do or stopped or hardware stopped. */
    if (uart_circ_empty(xmit) || uart_tx_stopped(&dport->port)) {
        spin_lock(&dport->port.lock);
        dz_stop_tx(&dport->port);
        spin_unlock(&dport->port.lock);
        return;
    }

    /*
     * If something to do... (remember the dz has no output fifo,
     * so we go one char at a time) :-<
     */
    tmp = xmit->buf[xmit->tail];
    xmit->tail = (xmit->tail + 1) & (DZ_XMIT_SIZE - 1);
    dz_out(dport, DZ_TDR, tmp);
    dport->port.icount.tx++;

    if (uart_circ_chars_pending(xmit) < DZ_WAKEUP_CHARS)
        uart_write_wakeup(&dport->port);

    /* Are we are done. */
    if (uart_circ_empty(xmit)) {
        spin_lock(&dport->port.lock);
        dz_stop_tx(&dport->port);
        spin_unlock(&dport->port.lock);
    }
}

/*
 * ------------------------------------------------------------
 * check_modem_status()
 *
 * DS 3100 & 5100: Only valid for the MODEM line, duh!
 * DS 5000/200: Valid for the MODEM and PRINTER line.
 * ------------------------------------------------------------
 */
static inline void check_modem_status(struct dz_port *dport)
{
    /*
     * FIXME:
     * 1. No status change interrupt; use a timer.
     * 2. Handle the 3100/5000 as appropriate. --macro
     */
    u16 status;

    /* If not the modem line just return.  */
    if (dport->port.line != DZ_MODEM)
        return;

    status = dz_in(dport, DZ_MSR);

    /* it's easy, since DSR2 is the only bit in the register */
    if (status)
        dport->port.icount.dsr++;
}

/*
 * ------------------------------------------------------------
 * dz_interrupt ()
 *
 * this is the main interrupt routine for the DZ chip.
 * It deals with the multiple ports.
 * ------------------------------------------------------------
 */
static irqreturn_t dz_interrupt(int irq, void *dev_id)
{
    struct dz_mux *mux = dev_id;
    struct dz_port *dport = &mux->dport[0];
    u16 status;

    /* get the reason why we just got an irq */
    status = dz_in(dport, DZ_CSR);

    if ((status & (DZ_RDONE | DZ_RIE)) == (DZ_RDONE | DZ_RIE))
        dz_receive_chars(mux);

    if ((status & (DZ_TRDY | DZ_TIE)) == (DZ_TRDY | DZ_TIE))
        dz_transmit_chars(mux);

    return IRQ_HANDLED;
}

/*
 * -------------------------------------------------------------------
 * Here ends the DZ interrupt routines.
 * -------------------------------------------------------------------
 */

static unsigned int dz_get_mctrl(struct uart_port *uport)
{
    /*
     * FIXME: Handle the 3100/5000 as appropriate. --macro
     */
    struct dz_port *dport = to_dport(uport);
    unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;

    if (dport->port.line == DZ_MODEM) {
        if (dz_in(dport, DZ_MSR) & DZ_MODEM_DSR)
            mctrl &= ~TIOCM_DSR;
    }

    return mctrl;
}

static void dz_set_mctrl(struct uart_port *uport, unsigned int mctrl)
{
    /*
     * FIXME: Handle the 3100/5000 as appropriate. --macro
     */
    struct dz_port *dport = to_dport(uport);
    u16 tmp;

    if (dport->port.line == DZ_MODEM) {
        tmp = dz_in(dport, DZ_TCR);
        if (mctrl & TIOCM_DTR)
            tmp &= ~DZ_MODEM_DTR;
        else
            tmp |= DZ_MODEM_DTR;
        dz_out(dport, DZ_TCR, tmp);
    }
}

/*
 * -------------------------------------------------------------------
 * startup ()
 *
 * various initialization tasks
 * -------------------------------------------------------------------
 */
static int dz_startup(struct uart_port *uport)
{
    struct dz_port *dport = to_dport(uport);
    struct dz_mux *mux = dport->mux;
    unsigned long flags;
    int irq_guard;
    int ret;
    u16 tmp;

    irq_guard = atomic_add_return(1, &mux->irq_guard);
    if (irq_guard != 1)
        return 0;

    ret = request_irq(dport->port.irq, dz_interrupt,
              IRQF_SHARED, "dz", mux);
    if (ret) {
        atomic_add(-1, &mux->irq_guard);
        printk(KERN_ERR "dz: Cannot get IRQ %d!\n", dport->port.irq);
        return ret;
    }

    spin_lock_irqsave(&dport->port.lock, flags);

    /* Enable interrupts.  */
    tmp = dz_in(dport, DZ_CSR);
    tmp |= DZ_RIE | DZ_TIE;
    dz_out(dport, DZ_CSR, tmp);

    spin_unlock_irqrestore(&dport->port.lock, flags);

    return 0;
}

/*
 * -------------------------------------------------------------------
 * shutdown ()
 *
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 * -------------------------------------------------------------------
 */
static void dz_shutdown(struct uart_port *uport)
{
    struct dz_port *dport = to_dport(uport);
    struct dz_mux *mux = dport->mux;
    unsigned long flags;
    int irq_guard;
    u16 tmp;

    spin_lock_irqsave(&dport->port.lock, flags);
    dz_stop_tx(&dport->port);
    spin_unlock_irqrestore(&dport->port.lock, flags);

    irq_guard = atomic_add_return(-1, &mux->irq_guard);
    if (!irq_guard) {
        /* Disable interrupts.  */
        tmp = dz_in(dport, DZ_CSR);
        tmp &= ~(DZ_RIE | DZ_TIE);
        dz_out(dport, DZ_CSR, tmp);

        free_irq(dport->port.irq, mux);
    }
}

/*
 * -------------------------------------------------------------------
 * dz_tx_empty() -- get the transmitter empty status
 *
 * Purpose: Let user call ioctl() to get info when the UART physically
 *          is emptied.  On bus types like RS485, the transmitter must
 *          release the bus after transmitting. This must be done when
 *          the transmit shift register is empty, not be done when the
 *          transmit holding register is empty.  This functionality
 *          allows an RS485 driver to be written in user space.
 * -------------------------------------------------------------------
 */
static unsigned int dz_tx_empty(struct uart_port *uport)
{
    struct dz_port *dport = to_dport(uport);
    unsigned short tmp, mask = 1 << dport->port.line;

    tmp = dz_in(dport, DZ_TCR);
    tmp &= mask;

    return tmp ? 0 : TIOCSER_TEMT;
}

static void dz_break_ctl(struct uart_port *uport, int break_state)
{
    /*
     * FIXME: Can't access BREAK bits in TDR easily;
     * reuse the code for polled TX. --macro
     */
    struct dz_port *dport = to_dport(uport);
    unsigned long flags;
    unsigned short tmp, mask = 1 << dport->port.line;

    spin_lock_irqsave(&uport->lock, flags);
    tmp = dz_in(dport, DZ_TCR);
    if (break_state)
        tmp |= mask;
    else
        tmp &= ~mask;
    dz_out(dport, DZ_TCR, tmp);
    spin_unlock_irqrestore(&uport->lock, flags);
}

static int dz_encode_baud_rate(unsigned int baud)
{
    switch (baud) {
    case 50:
        return DZ_B50;
    case 75:
        return DZ_B75;
    case 110:
        return DZ_B110;
    case 134:
        return DZ_B134;
    case 150:
        return DZ_B150;
    case 300:
        return DZ_B300;
    case 600:
        return DZ_B600;
    case 1200:
        return DZ_B1200;
    case 1800:
        return DZ_B1800;
    case 2000:
        return DZ_B2000;
    case 2400:
        return DZ_B2400;
    case 3600:
        return DZ_B3600;
    case 4800:
        return DZ_B4800;
    case 7200:
        return DZ_B7200;
    case 9600:
        return DZ_B9600;
    default:
        return -1;
    }
}


static void dz_reset(struct dz_port *dport)
{
    struct dz_mux *mux = dport->mux;

    if (mux->initialised)
        return;

    dz_out(dport, DZ_CSR, DZ_CLR);
    while (dz_in(dport, DZ_CSR) & DZ_CLR);
    iob();

    /* Enable scanning.  */
    dz_out(dport, DZ_CSR, DZ_MSE);

    mux->initialised = 1;
}

static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
               struct ktermios *old_termios)
{
    struct dz_port *dport = to_dport(uport);
    unsigned long flags;
    unsigned int cflag, baud;
    int bflag;

    cflag = dport->port.line;

    switch (termios->c_cflag & CSIZE) {
    case CS5:
        cflag |= DZ_CS5;
        break;
    case CS6:
        cflag |= DZ_CS6;
        break;
    case CS7:
        cflag |= DZ_CS7;
        break;
    case CS8:
    default:
        cflag |= DZ_CS8;
    }

    if (termios->c_cflag & CSTOPB)
        cflag |= DZ_CSTOPB;
    if (termios->c_cflag & PARENB)
        cflag |= DZ_PARENB;
    if (termios->c_cflag & PARODD)
        cflag |= DZ_PARODD;

    baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
    bflag = dz_encode_baud_rate(baud);
    if (bflag < 0)  {           /* Try to keep unchanged.  */
        baud = uart_get_baud_rate(uport, old_termios, NULL, 50, 9600);
        bflag = dz_encode_baud_rate(baud);
        if (bflag < 0)  {       /* Resort to 9600.  */
            baud = 9600;
            bflag = DZ_B9600;
        }
        tty_termios_encode_baud_rate(termios, baud, baud);
    }
    cflag |= bflag;

    if (termios->c_cflag & CREAD)
        cflag |= DZ_RXENAB;

    spin_lock_irqsave(&dport->port.lock, flags);

    uart_update_timeout(uport, termios->c_cflag, baud);

    dz_out(dport, DZ_LPR, cflag);
    dport->cflag = cflag;

    /* setup accept flag */
    dport->port.read_status_mask = DZ_OERR;
    if (termios->c_iflag & INPCK)
        dport->port.read_status_mask |= DZ_FERR | DZ_PERR;
    if (termios->c_iflag & (BRKINT | PARMRK))
        dport->port.read_status_mask |= DZ_BREAK;

    /* characters to ignore */
    uport->ignore_status_mask = 0;
    if ((termios->c_iflag & (IGNPAR | IGNBRK)) == (IGNPAR | IGNBRK))
        dport->port.ignore_status_mask |= DZ_OERR;
    if (termios->c_iflag & IGNPAR)
        dport->port.ignore_status_mask |= DZ_FERR | DZ_PERR;
    if (termios->c_iflag & IGNBRK)
        dport->port.ignore_status_mask |= DZ_BREAK;

    spin_unlock_irqrestore(&dport->port.lock, flags);
}

/*
 * Hack alert!
 * Required solely so that the initial PROM-based console
 * works undisturbed in parallel with this one.
 */
static void dz_pm(struct uart_port *uport, unsigned int state,
          unsigned int oldstate)
{
    struct dz_port *dport = to_dport(uport);
    unsigned long flags;

    spin_lock_irqsave(&dport->port.lock, flags);
    if (state < 3)
        dz_start_tx(&dport->port);
    else
        dz_stop_tx(&dport->port);
    spin_unlock_irqrestore(&dport->port.lock, flags);
}


static const char *dz_type(struct uart_port *uport)
{
    return "DZ";
}

static void dz_release_port(struct uart_port *uport)
{
    struct dz_mux *mux = to_dport(uport)->mux;
    int map_guard;

    iounmap(uport->membase);
    uport->membase = NULL;

    map_guard = atomic_add_return(-1, &mux->map_guard);
    if (!map_guard)
        release_mem_region(uport->mapbase, dec_kn_slot_size);
}

static int dz_map_port(struct uart_port *uport)
{
    if (!uport->membase)
        uport->membase = ioremap_nocache(uport->mapbase,
                         dec_kn_slot_size);
    if (!uport->membase) {
        printk(KERN_ERR "dz: Cannot map MMIO\n");
        return -ENOMEM;
    }
    return 0;
}

static int dz_request_port(struct uart_port *uport)
{
    struct dz_mux *mux = to_dport(uport)->mux;
    int map_guard;
    int ret;

    map_guard = atomic_add_return(1, &mux->map_guard);
    if (map_guard == 1) {
        if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
                    "dz")) {
            atomic_add(-1, &mux->map_guard);
            printk(KERN_ERR
                   "dz: Unable to reserve MMIO resource\n");
            return -EBUSY;
        }
    }
    ret = dz_map_port(uport);
    if (ret) {
        map_guard = atomic_add_return(-1, &mux->map_guard);
        if (!map_guard)
            release_mem_region(uport->mapbase, dec_kn_slot_size);
        return ret;
    }
    return 0;
}

static void dz_config_port(struct uart_port *uport, int flags)
{
    struct dz_port *dport = to_dport(uport);

    if (flags & UART_CONFIG_TYPE) {
        if (dz_request_port(uport))
            return;

        uport->type = PORT_DZ;

        dz_reset(dport);
    }
}

/*
 * Verify the new serial_struct (for TIOCSSERIAL).
 */
static int dz_verify_port(struct uart_port *uport, struct serial_struct *ser)
{
    int ret = 0;

    if (ser->type != PORT_UNKNOWN && ser->type != PORT_DZ)
        ret = -EINVAL;
    if (ser->irq != uport->irq)
        ret = -EINVAL;
    return ret;
}

static struct uart_ops dz_ops = {
    .tx_empty   = dz_tx_empty,
    .get_mctrl  = dz_get_mctrl,
    .set_mctrl  = dz_set_mctrl,
    .stop_tx    = dz_stop_tx,
    .start_tx   = dz_start_tx,
    .stop_rx    = dz_stop_rx,
    .enable_ms  = dz_enable_ms,
    .break_ctl  = dz_break_ctl,
    .startup    = dz_startup,
    .shutdown   = dz_shutdown,
    .set_termios    = dz_set_termios,
    .pm     = dz_pm,
    .type       = dz_type,
    .release_port   = dz_release_port,
    .request_port   = dz_request_port,
    .config_port    = dz_config_port,
    .verify_port    = dz_verify_port,
};

static void __init dz_init_ports(void)
{
    static int first = 1;
    unsigned long base;
    int line;

    if (!first)
        return;
    first = 0;

    if (mips_machtype == MACH_DS23100 || mips_machtype == MACH_DS5100)
        base = dec_kn_slot_base + KN01_DZ11;
    else
        base = dec_kn_slot_base + KN02_DZ11;

    for (line = 0; line < DZ_NB_PORT; line++) {
        struct dz_port *dport = &dz_mux.dport[line];
        struct uart_port *uport = &dport->port;

        dport->mux  = &dz_mux;

        uport->irq  = dec_interrupt[DEC_IRQ_DZ11];
        uport->fifosize = 1;
        uport->iotype   = UPIO_MEM;
        uport->flags    = UPF_BOOT_AUTOCONF;
        uport->ops  = &dz_ops;
        uport->line = line;
        uport->mapbase  = base;
    }
}

#ifdef CONFIG_SERIAL_DZ_CONSOLE
/*
 * -------------------------------------------------------------------
 * dz_console_putchar() -- transmit a character
 *
 * Polled transmission.  This is tricky.  We need to mask transmit
 * interrupts so that they do not interfere, enable the transmitter
 * for the line requested and then wait till the transmit scanner
 * requests data for this line.  But it may request data for another
 * line first, in which case we have to disable its transmitter and
 * repeat waiting till our line pops up.  Only then the character may
 * be transmitted.  Finally, the state of the transmitter mask is
 * restored.  Welcome to the world of PDP-11!
 * -------------------------------------------------------------------
 */
static void dz_console_putchar(struct uart_port *uport, int ch)
{
    struct dz_port *dport = to_dport(uport);
    unsigned long flags;
    unsigned short csr, tcr, trdy, mask;
    int loops = 10000;

    spin_lock_irqsave(&dport->port.lock, flags);
    csr = dz_in(dport, DZ_CSR);
    dz_out(dport, DZ_CSR, csr & ~DZ_TIE);
    tcr = dz_in(dport, DZ_TCR);
    tcr |= 1 << dport->port.line;
    mask = tcr;
    dz_out(dport, DZ_TCR, mask);
    iob();
    spin_unlock_irqrestore(&dport->port.lock, flags);

    do {
        trdy = dz_in(dport, DZ_CSR);
        if (!(trdy & DZ_TRDY))
            continue;
        trdy = (trdy & DZ_TLINE) >> 8;
        if (trdy == dport->port.line)
            break;
        mask &= ~(1 << trdy);
        dz_out(dport, DZ_TCR, mask);
        iob();
        udelay(2);
    } while (--loops);

    if (loops)              /* Cannot send otherwise. */
        dz_out(dport, DZ_TDR, ch);

    dz_out(dport, DZ_TCR, tcr);
    dz_out(dport, DZ_CSR, csr);
}

/*
 * -------------------------------------------------------------------
 * dz_console_print ()
 *
 * dz_console_print is registered for printk.
 * The console must be locked when we get here.
 * -------------------------------------------------------------------
 */
static void dz_console_print(struct console *co,
                 const char *str,
                 unsigned int count)
{
    struct dz_port *dport = &dz_mux.dport[co->index];
#ifdef DEBUG_DZ
    prom_printf((char *) str);
#endif
    uart_console_write(&dport->port, str, count, dz_console_putchar);
}

static int __init dz_console_setup(struct console *co, char *options)
{
    struct dz_port *dport = &dz_mux.dport[co->index];
    struct uart_port *uport = &dport->port;
    int baud = 9600;
    int bits = 8;
    int parity = 'n';
    int flow = 'n';
    int ret;

    ret = dz_map_port(uport);
    if (ret)
        return ret;

    spin_lock_init(&dport->port.lock);  /* For dz_pm().  */

    dz_reset(dport);
    dz_pm(uport, 0, -1);

    if (options)
        uart_parse_options(options, &baud, &parity, &bits, &flow);

    return uart_set_options(&dport->port, co, baud, parity, bits, flow);
}

static struct uart_driver dz_reg;
static struct console dz_console = {
    .name   = "ttyS",
    .write  = dz_console_print,
    .device = uart_console_device,
    .setup  = dz_console_setup,
    .flags  = CON_PRINTBUFFER,
    .index  = -1,
    .data   = &dz_reg,
};

static int __init dz_serial_console_init(void)
{
    if (!IOASIC) {
        dz_init_ports();
        register_console(&dz_console);
        return 0;
    } else
        return -ENXIO;
}

console_initcall(dz_serial_console_init);

#define SERIAL_DZ_CONSOLE   &dz_console
#else
#define SERIAL_DZ_CONSOLE   NULL
#endif /* CONFIG_SERIAL_DZ_CONSOLE */

static struct uart_driver dz_reg = {
    .owner          = THIS_MODULE,
    .driver_name        = "serial",
    .dev_name       = "ttyS",
    .major          = TTY_MAJOR,
    .minor          = 64,
    .nr         = DZ_NB_PORT,
    .cons           = SERIAL_DZ_CONSOLE,
};

static int __init dz_init(void)
{
    int ret, i;

    if (IOASIC)
        return -ENXIO;

    printk("%s%s\n", dz_name, dz_version);

    dz_init_ports();

    ret = uart_register_driver(&dz_reg);
    if (ret)
        return ret;

    for (i = 0; i < DZ_NB_PORT; i++)
        uart_add_one_port(&dz_reg, &dz_mux.dport[i].port);

    return 0;
}

module_init(dz_init);