[PATCH] TTY layer buffering revamp

[deliverable/linux.git] / drivers / serial / au1x00_uart.c

/*
 *  Driver for 8250/16550-type serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Copyright (C) 2001 Russell King.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * A note about mapbase / membase
 *
 *  mapbase is the physical address of the IO port.  Currently, we don't
 *  support this very well, and it may well be dropped from this driver
 *  in future.  As such, mapbase should be NULL.
 *
 *  membase is an 'ioremapped' cookie.  This is compatible with the old
 *  serial.c driver, and is currently the preferred form.
 */
#include <linux/config.h>
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/serial.h>
#include <linux/serialP.h>
#include <linux/delay.h>

#include <asm/serial.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mach-au1x00/au1000.h>

#if defined(CONFIG_SERIAL_AU1X00_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>
#include "8250.h"

/*
 * Debugging.
 */
#if 0
#define DEBUG_AUTOCONF(fmt...)  printk(fmt)
#else
#define DEBUG_AUTOCONF(fmt...)  do { } while (0)
#endif

#if 0
#define DEBUG_INTR(fmt...)      printk(fmt)
#else
#define DEBUG_INTR(fmt...)      do { } while (0)
#endif

#define PASS_LIMIT      256

/*
 * We default to IRQ0 for the "no irq" hack.   Some
 * machine types want others as well - they're free
 * to redefine this in their header file.
 */
#define is_real_interrupt(irq)  ((irq) != 0)

static struct old_serial_port old_serial_port[] = {
        {       .baud_base = 0,
                .iomem_base = (u8 *)UART0_ADDR,
                .irq = AU1000_UART0_INT,
                .flags = STD_COM_FLAGS,
                .iomem_reg_shift = 2,
        }, {
                .baud_base = 0,
                .iomem_base = (u8 *)UART1_ADDR,
                .irq = AU1000_UART1_INT,
                .flags = STD_COM_FLAGS,
                .iomem_reg_shift = 2
        }, {
                .baud_base = 0,
                .iomem_base = (u8 *)UART2_ADDR,
                .irq = AU1000_UART2_INT,
                .flags = STD_COM_FLAGS,
                .iomem_reg_shift = 2
        }, {
                .baud_base = 0,
                .iomem_base = (u8 *)UART3_ADDR,
                .irq = AU1000_UART3_INT,
                .flags = STD_COM_FLAGS,
                .iomem_reg_shift = 2
        }
};

#define UART_NR ARRAY_SIZE(old_serial_port)

struct uart_8250_port {
        struct uart_port        port;
        struct timer_list       timer;          /* "no irq" timer */
        struct list_head        list;           /* ports on this IRQ */
        unsigned short          rev;
        unsigned char           acr;
        unsigned char           ier;
        unsigned char           lcr;
        unsigned char           mcr_mask;       /* mask of user bits */
        unsigned char           mcr_force;      /* mask of forced bits */
        unsigned char           lsr_break_flag;

        /*
         * We provide a per-port pm hook.
         */
        void                    (*pm)(struct uart_port *port,
                                      unsigned int state, unsigned int old);
};

struct irq_info {
        spinlock_t              lock;
        struct list_head        *head;
};

static struct irq_info irq_lists[NR_IRQS];

/*
 * Here we define the default xmit fifo size used for each type of UART.
 */
static const struct serial_uart_config uart_config[PORT_MAX_8250+1] = {
        { "unknown",    1,      0 },
        { "8250",       1,      0 },
        { "16450",      1,      0 },
        { "16550",      1,      0 },
        /* PORT_16550A */
        { "AU1X00_UART",16,     UART_CLEAR_FIFO | UART_USE_FIFO },
};

static _INLINE_ unsigned int serial_in(struct uart_8250_port *up, int offset)
{
        return au_readl((unsigned long)up->port.membase + offset);
}

static _INLINE_ void
serial_out(struct uart_8250_port *up, int offset, int value)
{
        au_writel(value, (unsigned long)up->port.membase + offset);
}

#define serial_inp(up, offset)          serial_in(up, offset)
#define serial_outp(up, offset, value)  serial_out(up, offset, value)

/*
 * This routine is called by rs_init() to initialize a specific serial
 * port.  It determines what type of UART chip this serial port is
 * using: 8250, 16450, 16550, 16550A.  The important question is
 * whether or not this UART is a 16550A or not, since this will
 * determine whether or not we can use its FIFO features or not.
 */
static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
{
        unsigned char save_lcr, save_mcr;
        unsigned long flags;

        if (!up->port.iobase && !up->port.mapbase && !up->port.membase)
                return;

        DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04x, 0x%08lx): ",
                        up->port.line, up->port.iobase, up->port.membase);

        /*
         * We really do need global IRQs disabled here - we're going to
         * be frobbing the chips IRQ enable register to see if it exists.
         */
        spin_lock_irqsave(&up->port.lock, flags);
//      save_flags(flags); cli();

        save_mcr = serial_in(up, UART_MCR);
        save_lcr = serial_in(up, UART_LCR);

        up->port.type = PORT_16550A;
        serial_outp(up, UART_LCR, save_lcr);

        up->port.fifosize = uart_config[up->port.type].dfl_xmit_fifo_size;

        if (up->port.type == PORT_UNKNOWN)
                goto out;

        /*
         * Reset the UART.
         */
        serial_outp(up, UART_MCR, save_mcr);
        serial_outp(up, UART_FCR, (UART_FCR_ENABLE_FIFO |
                                     UART_FCR_CLEAR_RCVR |
                                     UART_FCR_CLEAR_XMIT));
        serial_outp(up, UART_FCR, 0);
        (void)serial_in(up, UART_RX);
        serial_outp(up, UART_IER, 0);

 out:   
        spin_unlock_irqrestore(&up->port.lock, flags);
//      restore_flags(flags);
        DEBUG_AUTOCONF("type=%s\n", uart_config[up->port.type].name);
}

static void serial8250_stop_tx(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;

        if (up->ier & UART_IER_THRI) {
                up->ier &= ~UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
        }
}

static void serial8250_start_tx(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;

        if (!(up->ier & UART_IER_THRI)) {
                up->ier |= UART_IER_THRI;
                serial_out(up, UART_IER, up->ier);
        }
}

static void serial8250_stop_rx(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;

        up->ier &= ~UART_IER_RLSI;
        up->port.read_status_mask &= ~UART_LSR_DR;
        serial_out(up, UART_IER, up->ier);
}

static void serial8250_enable_ms(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;

        up->ier |= UART_IER_MSI;
        serial_out(up, UART_IER, up->ier);
}

static _INLINE_ void
receive_chars(struct uart_8250_port *up, int *status, struct pt_regs *regs)
{
        struct tty_struct *tty = up->port.info->tty;
        unsigned char ch, flag;
        int max_count = 256;

        do {
                ch = serial_inp(up, UART_RX);
                flag = TTY_NORMAL;
                up->port.icount.rx++;

                if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
                                       UART_LSR_FE | UART_LSR_OE))) {
                        /*
                         * For statistics only
                         */
                        if (*status & UART_LSR_BI) {
                                *status &= ~(UART_LSR_FE | UART_LSR_PE);
                                up->port.icount.brk++;
                                /*
                                 * We do the SysRQ and SAK checking
                                 * here because otherwise the break
                                 * may get masked by ignore_status_mask
                                 * or read_status_mask.
                                 */
                                if (uart_handle_break(&up->port))
                                        goto ignore_char;
                        } else if (*status & UART_LSR_PE)
                                up->port.icount.parity++;
                        else if (*status & UART_LSR_FE)
                                up->port.icount.frame++;
                        if (*status & UART_LSR_OE)
                                up->port.icount.overrun++;

                        /*
                         * Mask off conditions which should be ingored.
                         */
                        *status &= up->port.read_status_mask;

#ifdef CONFIG_SERIAL_AU1X00_CONSOLE
                        if (up->port.line == up->port.cons->index) {
                                /* Recover the break flag from console xmit */
                                *status |= up->lsr_break_flag;
                                up->lsr_break_flag = 0;
                        }
#endif
                        if (*status & UART_LSR_BI) {
                                DEBUG_INTR("handling break....");
                                flag = TTY_BREAK;
                        } else if (*status & UART_LSR_PE)
                                flag = TTY_PARITY;
                        else if (*status & UART_LSR_FE)
                                flag = TTY_FRAME;
                }
                if (uart_handle_sysrq_char(&up->port, ch, regs))
                        goto ignore_char;
                if ((*status & up->port.ignore_status_mask) == 0)
                        tty_insert_flip_char(tty, ch, flag);
                if (*status & UART_LSR_OE)
                        /*
                         * Overrun is special, since it's reported
                         * immediately, and doesn't affect the current
                         * character.
                         */
                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
                }
        ignore_char:
                *status = serial_inp(up, UART_LSR);
        } while ((*status & UART_LSR_DR) && (max_count-- > 0));
        spin_unlock(&up->port.lock);
        tty_flip_buffer_push(tty);
        spin_lock(&up->port.lock);
}

static _INLINE_ void transmit_chars(struct uart_8250_port *up)
{
        struct circ_buf *xmit = &up->port.info->xmit;
        int count;

        if (up->port.x_char) {
                serial_outp(up, UART_TX, up->port.x_char);
                up->port.icount.tx++;
                up->port.x_char = 0;
                return;
        }
        if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
                serial8250_stop_tx(&up->port);
                return;
        }

        count = up->port.fifosize;
        do {
                serial_out(up, UART_TX, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                up->port.icount.tx++;
                if (uart_circ_empty(xmit))
                        break;
        } while (--count > 0);

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(&up->port);

        DEBUG_INTR("THRE...");

        if (uart_circ_empty(xmit))
                serial8250_stop_tx(&up->port);
}

static _INLINE_ void check_modem_status(struct uart_8250_port *up)
{
        int status;

        status = serial_in(up, UART_MSR);

        if ((status & UART_MSR_ANY_DELTA) == 0)
                return;

        if (status & UART_MSR_TERI)
                up->port.icount.rng++;
        if (status & UART_MSR_DDSR)
                up->port.icount.dsr++;
        if (status & UART_MSR_DDCD)
                uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
        if (status & UART_MSR_DCTS)
                uart_handle_cts_change(&up->port, status & UART_MSR_CTS);

        wake_up_interruptible(&up->port.info->delta_msr_wait);
}

/*
 * This handles the interrupt from one port.
 */
static inline void
serial8250_handle_port(struct uart_8250_port *up, struct pt_regs *regs)
{
        unsigned int status = serial_inp(up, UART_LSR);

        DEBUG_INTR("status = %x...", status);

        if (status & UART_LSR_DR)
                receive_chars(up, &status, regs);
        check_modem_status(up);
        if (status & UART_LSR_THRE)
                transmit_chars(up);
}

/*
 * This is the serial driver's interrupt routine.
 *
 * Arjan thinks the old way was overly complex, so it got simplified.
 * Alan disagrees, saying that need the complexity to handle the weird
 * nature of ISA shared interrupts.  (This is a special exception.)
 *
 * In order to handle ISA shared interrupts properly, we need to check
 * that all ports have been serviced, and therefore the ISA interrupt
 * line has been de-asserted.
 *
 * This means we need to loop through all ports. checking that they
 * don't have an interrupt pending.
 */
static irqreturn_t serial8250_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        struct irq_info *i = dev_id;
        struct list_head *l, *end = NULL;
        int pass_counter = 0;

        DEBUG_INTR("serial8250_interrupt(%d)...", irq);

        spin_lock(&i->lock);

        l = i->head;
        do {
                struct uart_8250_port *up;
                unsigned int iir;

                up = list_entry(l, struct uart_8250_port, list);

                iir = serial_in(up, UART_IIR);
                if (!(iir & UART_IIR_NO_INT)) {
                        spin_lock(&up->port.lock);
                        serial8250_handle_port(up, regs);
                        spin_unlock(&up->port.lock);

                        end = NULL;
                } else if (end == NULL)
                        end = l;

                l = l->next;

                if (l == i->head && pass_counter++ > PASS_LIMIT) {
                        /* If we hit this, we're dead. */
                        printk(KERN_ERR "serial8250: too much work for "
                                "irq%d\n", irq);
                        break;
                }
        } while (l != end);

        spin_unlock(&i->lock);

        DEBUG_INTR("end.\n");
        /* FIXME! Was it really ours? */
        return IRQ_HANDLED;
}

/*
 * To support ISA shared interrupts, we need to have one interrupt
 * handler that ensures that the IRQ line has been deasserted
 * before returning.  Failing to do this will result in the IRQ
 * line being stuck active, and, since ISA irqs are edge triggered,
 * no more IRQs will be seen.
 */
static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
{
        spin_lock_irq(&i->lock);

        if (!list_empty(i->head)) {
                if (i->head == &up->list)
                        i->head = i->head->next;
                list_del(&up->list);
        } else {
                BUG_ON(i->head != &up->list);
                i->head = NULL;
        }

        spin_unlock_irq(&i->lock);
}

static int serial_link_irq_chain(struct uart_8250_port *up)
{
        struct irq_info *i = irq_lists + up->port.irq;
        int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? SA_SHIRQ : 0;

        spin_lock_irq(&i->lock);

        if (i->head) {
                list_add(&up->list, i->head);
                spin_unlock_irq(&i->lock);

                ret = 0;
        } else {
                INIT_LIST_HEAD(&up->list);
                i->head = &up->list;
                spin_unlock_irq(&i->lock);

                ret = request_irq(up->port.irq, serial8250_interrupt,
                                  irq_flags, "serial", i);
                if (ret < 0)
                        serial_do_unlink(i, up);
        }

        return ret;
}

static void serial_unlink_irq_chain(struct uart_8250_port *up)
{
        struct irq_info *i = irq_lists + up->port.irq;

        BUG_ON(i->head == NULL);

        if (list_empty(i->head))
                free_irq(up->port.irq, i);

        serial_do_unlink(i, up);
}

/*
 * This function is used to handle ports that do not have an
 * interrupt.  This doesn't work very well for 16450's, but gives
 * barely passable results for a 16550A.  (Although at the expense
 * of much CPU overhead).
 */
static void serial8250_timeout(unsigned long data)
{
        struct uart_8250_port *up = (struct uart_8250_port *)data;
        unsigned int timeout;
        unsigned int iir;

        iir = serial_in(up, UART_IIR);
        if (!(iir & UART_IIR_NO_INT)) {
                spin_lock(&up->port.lock);
                serial8250_handle_port(up, NULL);
                spin_unlock(&up->port.lock);
        }

        timeout = up->port.timeout;
        timeout = timeout > 6 ? (timeout / 2 - 2) : 1;
        mod_timer(&up->timer, jiffies + timeout);
}

static unsigned int serial8250_tx_empty(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned long flags;
        unsigned int ret;

        spin_lock_irqsave(&up->port.lock, flags);
        ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
        spin_unlock_irqrestore(&up->port.lock, flags);

        return ret;
}

static unsigned int serial8250_get_mctrl(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned char status;
        unsigned int ret;

        status = serial_in(up, UART_MSR);

        ret = 0;
        if (status & UART_MSR_DCD)
                ret |= TIOCM_CAR;
        if (status & UART_MSR_RI)
                ret |= TIOCM_RNG;
        if (status & UART_MSR_DSR)
                ret |= TIOCM_DSR;
        if (status & UART_MSR_CTS)
                ret |= TIOCM_CTS;
        return ret;
}

static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned char mcr = 0;

        if (mctrl & TIOCM_RTS)
                mcr |= UART_MCR_RTS;
        if (mctrl & TIOCM_DTR)
                mcr |= UART_MCR_DTR;
        if (mctrl & TIOCM_OUT1)
                mcr |= UART_MCR_OUT1;
        if (mctrl & TIOCM_OUT2)
                mcr |= UART_MCR_OUT2;
        if (mctrl & TIOCM_LOOP)
                mcr |= UART_MCR_LOOP;

        mcr = (mcr & up->mcr_mask) | up->mcr_force;

        serial_out(up, UART_MCR, mcr);
}

static void serial8250_break_ctl(struct uart_port *port, int break_state)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned long flags;

        spin_lock_irqsave(&up->port.lock, flags);
        if (break_state == -1)
                up->lcr |= UART_LCR_SBC;
        else
                up->lcr &= ~UART_LCR_SBC;
        serial_out(up, UART_LCR, up->lcr);
        spin_unlock_irqrestore(&up->port.lock, flags);
}

static int serial8250_startup(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned long flags;
        int retval;

        /*
         * Clear the FIFO buffers and disable them.
         * (they will be reeanbled in set_termios())
         */
        if (uart_config[up->port.type].flags & UART_CLEAR_FIFO) {
                serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
                serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                                UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
                serial_outp(up, UART_FCR, 0);
        }

        /*
         * Clear the interrupt registers.
         */
        (void) serial_inp(up, UART_LSR);
        (void) serial_inp(up, UART_RX);
        (void) serial_inp(up, UART_IIR);
        (void) serial_inp(up, UART_MSR);

        /*
         * At this point, there's no way the LSR could still be 0xff;
         * if it is, then bail out, because there's likely no UART
         * here.
         */
        if (!(up->port.flags & UPF_BUGGY_UART) &&
            (serial_inp(up, UART_LSR) == 0xff)) {
                printk("ttyS%d: LSR safety check engaged!\n", up->port.line);
                return -ENODEV;
        }

        retval = serial_link_irq_chain(up);
                if (retval)
                        return retval;

        /*
         * Now, initialize the UART
         */
        serial_outp(up, UART_LCR, UART_LCR_WLEN8);

        spin_lock_irqsave(&up->port.lock, flags);
        if (up->port.flags & UPF_FOURPORT) {
                if (!is_real_interrupt(up->port.irq))
                        up->port.mctrl |= TIOCM_OUT1;
        } else
                /*
                 * Most PC uarts need OUT2 raised to enable interrupts.
                 */
                if (is_real_interrupt(up->port.irq))
                        up->port.mctrl |= TIOCM_OUT2;

        serial8250_set_mctrl(&up->port, up->port.mctrl);
        spin_unlock_irqrestore(&up->port.lock, flags);

        /*
         * Finally, enable interrupts.  Note: Modem status interrupts
         * are set via set_termios(), which will be occurring imminently
         * anyway, so we don't enable them here.
         */
        up->ier = UART_IER_RLSI | UART_IER_RDI;
        serial_outp(up, UART_IER, up->ier);

        if (up->port.flags & UPF_FOURPORT) {
                unsigned int icp;
                /*
                 * Enable interrupts on the AST Fourport board
                 */
                icp = (up->port.iobase & 0xfe0) | 0x01f;
                outb_p(0x80, icp);
                (void) inb_p(icp);
        }

        /*
         * And clear the interrupt registers again for luck.
         */
        (void) serial_inp(up, UART_LSR);
        (void) serial_inp(up, UART_RX);
        (void) serial_inp(up, UART_IIR);
        (void) serial_inp(up, UART_MSR);

        return 0;
}

static void serial8250_shutdown(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned long flags;

        /*
         * Disable interrupts from this port
         */
        up->ier = 0;
        serial_outp(up, UART_IER, 0);

        spin_lock_irqsave(&up->port.lock, flags);
        if (up->port.flags & UPF_FOURPORT) {
                /* reset interrupts on the AST Fourport board */
                inb((up->port.iobase & 0xfe0) | 0x1f);
                up->port.mctrl |= TIOCM_OUT1;
        } else
                up->port.mctrl &= ~TIOCM_OUT2;

        serial8250_set_mctrl(&up->port, up->port.mctrl);
        spin_unlock_irqrestore(&up->port.lock, flags);

        /*
         * Disable break condition and FIFOs
         */
        serial_out(up, UART_LCR, serial_inp(up, UART_LCR) & ~UART_LCR_SBC);
        serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                                  UART_FCR_CLEAR_RCVR |
                                  UART_FCR_CLEAR_XMIT);
        serial_outp(up, UART_FCR, 0);

        /*
         * Read data port to reset things, and then unlink from
         * the IRQ chain.
         */
        (void) serial_in(up, UART_RX);

        if (!is_real_interrupt(up->port.irq))
                del_timer_sync(&up->timer);
        else
                serial_unlink_irq_chain(up);
}

static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int baud)
{
        unsigned int quot;

        /*
         * Handle magic divisors for baud rates above baud_base on
         * SMSC SuperIO chips.
         */
        if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
            baud == (port->uartclk/4))
                quot = 0x8001;
        else if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
                 baud == (port->uartclk/8))
                quot = 0x8002;
        else
                quot = uart_get_divisor(port, baud);

        return quot;
}

static void
serial8250_set_termios(struct uart_port *port, struct termios *termios,
                       struct termios *old)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned char cval, fcr = 0;
        unsigned long flags;
        unsigned int baud, quot;

        switch (termios->c_cflag & CSIZE) {
        case CS5:
                cval = UART_LCR_WLEN5;
                break;
        case CS6:
                cval = UART_LCR_WLEN6;
                break;
        case CS7:
                cval = UART_LCR_WLEN7;
                break;
        default:
        case CS8:
                cval = UART_LCR_WLEN8;
                break;
        }

        if (termios->c_cflag & CSTOPB)
                cval |= UART_LCR_STOP;
        if (termios->c_cflag & PARENB)
                cval |= UART_LCR_PARITY;
        if (!(termios->c_cflag & PARODD))
                cval |= UART_LCR_EPAR;
#ifdef CMSPAR
        if (termios->c_cflag & CMSPAR)
                cval |= UART_LCR_SPAR;
#endif

        /*
         * Ask the core to calculate the divisor for us.
         */
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); 
        quot = serial8250_get_divisor(port, baud);
        quot = 0x35; /* FIXME */

        /*
         * Work around a bug in the Oxford Semiconductor 952 rev B
         * chip which causes it to seriously miscalculate baud rates
         * when DLL is 0.
         */
        if ((quot & 0xff) == 0 && up->port.type == PORT_16C950 &&
            up->rev == 0x5201)
                quot ++;

        if (uart_config[up->port.type].flags & UART_USE_FIFO) {
                if (baud < 2400)
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIGGER_1;
                else
                        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIGGER_8;
        }

        /*
         * Ok, we're now changing the port state.  Do it with
         * interrupts disabled.
         */
        spin_lock_irqsave(&up->port.lock, flags);

        /*
         * Update the per-port timeout.
         */
        uart_update_timeout(port, termios->c_cflag, baud);

        up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
        if (termios->c_iflag & INPCK)
                up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
        if (termios->c_iflag & (BRKINT | PARMRK))
                up->port.read_status_mask |= UART_LSR_BI;

        /*
         * Characteres to ignore
         */
        up->port.ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
        if (termios->c_iflag & IGNBRK) {
                up->port.ignore_status_mask |= UART_LSR_BI;
                /*
                 * If we're ignoring parity and break indicators,
                 * ignore overruns too (for real raw support).
                 */
                if (termios->c_iflag & IGNPAR)
                        up->port.ignore_status_mask |= UART_LSR_OE;
        }

        /*
         * ignore all characters if CREAD is not set
         */
        if ((termios->c_cflag & CREAD) == 0)
                up->port.ignore_status_mask |= UART_LSR_DR;

        /*
         * CTS flow control flag and modem status interrupts
         */
        up->ier &= ~UART_IER_MSI;
        if (UART_ENABLE_MS(&up->port, termios->c_cflag))
                up->ier |= UART_IER_MSI;

        serial_out(up, UART_IER, up->ier);
        serial_outp(up, 0x28, quot & 0xffff);
        up->lcr = cval;                                 /* Save LCR */
        if (up->port.type != PORT_16750) {
                if (fcr & UART_FCR_ENABLE_FIFO) {
                        /* emulated UARTs (Lucent Venus 167x) need two steps */
                        serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
                }
                serial_outp(up, UART_FCR, fcr);         /* set fcr */
        }
        spin_unlock_irqrestore(&up->port.lock, flags);
}

static void
serial8250_pm(struct uart_port *port, unsigned int state,
              unsigned int oldstate)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        if (state) {
                /* sleep */
                if (up->pm)
                        up->pm(port, state, oldstate);
        } else {
                /* wake */
                if (up->pm)
                        up->pm(port, state, oldstate);
        }
}

/*
 * Resource handling.  This is complicated by the fact that resources
 * depend on the port type.  Maybe we should be claiming the standard
 * 8250 ports, and then trying to get other resources as necessary?
 */
static int
serial8250_request_std_resource(struct uart_8250_port *up, struct resource **res)
{
        unsigned int size = 8 << up->port.regshift;
        int ret = 0;

        switch (up->port.iotype) {
        case SERIAL_IO_MEM:
                if (up->port.mapbase) {
                        *res = request_mem_region(up->port.mapbase, size, "serial");
                        if (!*res)
                                ret = -EBUSY;
                }
                break;

        case SERIAL_IO_HUB6:
        case SERIAL_IO_PORT:
                *res = request_region(up->port.iobase, size, "serial");
                if (!*res)
                        ret = -EBUSY;
                break;
        }
        return ret;
}


static void serial8250_release_port(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned long start, offset = 0, size = 0;

        size <<= up->port.regshift;

        switch (up->port.iotype) {
        case SERIAL_IO_MEM:
                if (up->port.mapbase) {
                        /*
                         * Unmap the area.
                         */
                        iounmap(up->port.membase);
                        up->port.membase = NULL;

                        start = up->port.mapbase;

                        if (size)
                                release_mem_region(start + offset, size);
                        release_mem_region(start, 8 << up->port.regshift);
                }
                break;

        case SERIAL_IO_HUB6:
        case SERIAL_IO_PORT:
                start = up->port.iobase;

                if (size)
                        release_region(start + offset, size);
                release_region(start + offset, 8 << up->port.regshift);
                break;

        default:
                break;
        }
}

static int serial8250_request_port(struct uart_port *port)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        struct resource *res = NULL, *res_rsa = NULL;
        int ret = 0;

        ret = serial8250_request_std_resource(up, &res);

        /*
         * If we have a mapbase, then request that as well.
         */
        if (ret == 0 && up->port.flags & UPF_IOREMAP) {
                int size = res->end - res->start + 1;

                up->port.membase = ioremap(up->port.mapbase, size);
                if (!up->port.membase)
                        ret = -ENOMEM;
        }

        if (ret < 0) {
                if (res_rsa)
                        release_resource(res_rsa);
                if (res)
                        release_resource(res);
        }
        return ret;
}

static void serial8250_config_port(struct uart_port *port, int flags)
{
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        struct resource *res_std = NULL, *res_rsa = NULL;
        int probeflags = PROBE_ANY;

        probeflags &= ~PROBE_RSA;

        if (flags & UART_CONFIG_TYPE)
                autoconfig(up, probeflags);

        /*
         * If the port wasn't an RSA port, release the resource.
         */
        if (up->port.type != PORT_RSA && res_rsa)
                release_resource(res_rsa);

        if (up->port.type == PORT_UNKNOWN && res_std)
                release_resource(res_std);
}

static int
serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        if (ser->irq >= NR_IRQS || ser->irq < 0 ||
            ser->baud_base < 9600 || ser->type < PORT_UNKNOWN ||
            ser->type > PORT_MAX_8250 || ser->type == PORT_CIRRUS ||
            ser->type == PORT_STARTECH)
                return -EINVAL;
        return 0;
}

static const char *
serial8250_type(struct uart_port *port)
{
        int type = port->type;

        if (type >= ARRAY_SIZE(uart_config))
                type = 0;
        return uart_config[type].name;
}

static struct uart_ops serial8250_pops = {
        .tx_empty       = serial8250_tx_empty,
        .set_mctrl      = serial8250_set_mctrl,
        .get_mctrl      = serial8250_get_mctrl,
        .stop_tx        = serial8250_stop_tx,
        .start_tx       = serial8250_start_tx,
        .stop_rx        = serial8250_stop_rx,
        .enable_ms      = serial8250_enable_ms,
        .break_ctl      = serial8250_break_ctl,
        .startup        = serial8250_startup,
        .shutdown       = serial8250_shutdown,
        .set_termios    = serial8250_set_termios,
        .pm             = serial8250_pm,
        .type           = serial8250_type,
        .release_port   = serial8250_release_port,
        .request_port   = serial8250_request_port,
        .config_port    = serial8250_config_port,
        .verify_port    = serial8250_verify_port,
};

static struct uart_8250_port serial8250_ports[UART_NR];

static void __init serial8250_isa_init_ports(void)
{
        struct uart_8250_port *up;
        static int first = 1;
        int i;

        if (!first)
                return;
        first = 0;

        for (i = 0, up = serial8250_ports; i < ARRAY_SIZE(old_serial_port);
             i++, up++) {
                up->port.iobase   = old_serial_port[i].port;
                up->port.irq      = old_serial_port[i].irq;
                up->port.uartclk  = get_au1x00_uart_baud_base();
                up->port.flags    = old_serial_port[i].flags;
                up->port.hub6     = old_serial_port[i].hub6;
                up->port.membase  = old_serial_port[i].iomem_base;
                up->port.iotype   = old_serial_port[i].io_type;
                up->port.regshift = old_serial_port[i].iomem_reg_shift;
                up->port.ops      = &serial8250_pops;
        }
}

static void __init serial8250_register_ports(struct uart_driver *drv)
{
        int i;

        serial8250_isa_init_ports();

        for (i = 0; i < UART_NR; i++) {
                struct uart_8250_port *up = &serial8250_ports[i];

                up->port.line = i;
                up->port.ops = &serial8250_pops;
                init_timer(&up->timer);
                up->timer.function = serial8250_timeout;

                /*
                 * ALPHA_KLUDGE_MCR needs to be killed.
                 */
                up->mcr_mask = ~ALPHA_KLUDGE_MCR;
                up->mcr_force = ALPHA_KLUDGE_MCR;

                uart_add_one_port(drv, &up->port);
        }
}

#ifdef CONFIG_SERIAL_AU1X00_CONSOLE

#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

/*
 *      Wait for transmitter & holding register to empty
 */
static inline void wait_for_xmitr(struct uart_8250_port *up)
{
        unsigned int status, tmout = 10000;

        /* Wait up to 10ms for the character(s) to be sent. */
        do {
                status = serial_in(up, UART_LSR);

                if (status & UART_LSR_BI)
                        up->lsr_break_flag = UART_LSR_BI;

                if (--tmout == 0)
                        break;
                udelay(1);
        } while ((status & BOTH_EMPTY) != BOTH_EMPTY);

        /* Wait up to 1s for flow control if necessary */
        if (up->port.flags & UPF_CONS_FLOW) {
                tmout = 1000000;
                while (--tmout &&
                       ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
                        udelay(1);
        }
}

/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 *
 *      The console_lock must be held when we get here.
 */
static void
serial8250_console_write(struct console *co, const char *s, unsigned int count)
{
        struct uart_8250_port *up = &serial8250_ports[co->index];
        unsigned int ier;
        int i;

        /*
         *      First save the UER then disable the interrupts
         */
        ier = serial_in(up, UART_IER);
        serial_out(up, UART_IER, 0);

        /*
         *      Now, do each character
         */
        for (i = 0; i < count; i++, s++) {
                wait_for_xmitr(up);

                /*
                 *      Send the character out.
                 *      If a LF, also do CR...
                 */
                serial_out(up, UART_TX, *s);
                if (*s == 10) {
                        wait_for_xmitr(up);
                        serial_out(up, UART_TX, 13);
                }
        }

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore the IER
         */
        wait_for_xmitr(up);
        serial_out(up, UART_IER, ier);
}

static int __init serial8250_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        /*
         * Check whether an invalid uart number has been specified, and
         * if so, search for the first available port that does have
         * console support.
         */
        if (co->index >= UART_NR)
                co->index = 0;
        port = &serial8250_ports[co->index].port;

        /*
         * Temporary fix.
         */
        spin_lock_init(&port->lock);

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

        return uart_set_options(port, co, baud, parity, bits, flow);
}

extern struct uart_driver serial8250_reg;
static struct console serial8250_console = {
        .name           = "ttyS",
        .write          = serial8250_console_write,
        .device         = uart_console_device,
        .setup          = serial8250_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &serial8250_reg,
};

static int __init serial8250_console_init(void)
{
        serial8250_isa_init_ports();
        register_console(&serial8250_console);
        return 0;
}
console_initcall(serial8250_console_init);

#define SERIAL8250_CONSOLE      &serial8250_console
#else
#define SERIAL8250_CONSOLE      NULL
#endif

static struct uart_driver serial8250_reg = {
        .owner                  = THIS_MODULE,
        .driver_name            = "serial",
        .devfs_name             = "tts/",
        .dev_name               = "ttyS",
        .major                  = TTY_MAJOR,
        .minor                  = 64,
        .nr                     = UART_NR,
        .cons                   = SERIAL8250_CONSOLE,
};

int __init early_serial_setup(struct uart_port *port)
{
        serial8250_isa_init_ports();
        serial8250_ports[port->line].port       = *port;
        serial8250_ports[port->line].port.ops   = &serial8250_pops;
        return 0;
}

/**
 *      serial8250_suspend_port - suspend one serial port
 *      @line:  serial line number
 *      @level: the level of port suspension, as per uart_suspend_port
 *
 *      Suspend one serial port.
 */
void serial8250_suspend_port(int line)
{
        uart_suspend_port(&serial8250_reg, &serial8250_ports[line].port);
}

/**
 *      serial8250_resume_port - resume one serial port
 *      @line:  serial line number
 *      @level: the level of port resumption, as per uart_resume_port
 *
 *      Resume one serial port.
 */
void serial8250_resume_port(int line)
{
        uart_resume_port(&serial8250_reg, &serial8250_ports[line].port);
}

static int __init serial8250_init(void)
{
        int ret, i;

        printk(KERN_INFO "Serial: Au1x00 driver\n");

        for (i = 0; i < NR_IRQS; i++)
                spin_lock_init(&irq_lists[i].lock);

        ret = uart_register_driver(&serial8250_reg);
        if (ret >= 0)
                serial8250_register_ports(&serial8250_reg);

        return ret;
}

static void __exit serial8250_exit(void)
{
        int i;

        for (i = 0; i < UART_NR; i++)
                uart_remove_one_port(&serial8250_reg, &serial8250_ports[i].port);

        uart_unregister_driver(&serial8250_reg);
}

module_init(serial8250_init);
module_exit(serial8250_exit);

EXPORT_SYMBOL(serial8250_suspend_port);
EXPORT_SYMBOL(serial8250_resume_port);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Au1x00 serial driver\n");