Coarsly sort out 32-bit-only, 64-bit-only and ``portable'' MIPS lib/

[linux-2.6/linux-mips.git] / drivers / char / sb1250_duart.c

/*
 * Copyright (C) 2000, 2001, 2002, 2003 Broadcom Corporation
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

/* 
 * Driver support for the on-chip sb1250 dual-channel serial port,
 * running in asynchronous mode.  Also, support for doing a serial console
 * on one of those ports 
 */
#include <linux/config.h>
#include <linux/types.h>
#include <linux/serial.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/console.h>
#include <linux/kdev_t.h>
#include <linux/major.h>
#include <linux/termios.h>
#include <linux/spinlock.h>
#include <linux/irq.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/sched.h>
#include <linux/tty_flip.h>
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <asm/delay.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/sibyte/swarm.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_uart.h>
#include <asm/sibyte/sb1250_int.h>
#include <asm/sibyte/sb1250.h>
#include <asm/war.h>

/* Toggle spewing of debugging output */
#undef DUART_SPEW

#define DEFAULT_CFLAGS          (CS8 | B115200)

#define TX_INTEN          1
#define DUART_INITIALIZED 2

#ifndef MIN
#define MIN(a,b)        ((a) < (b) ? (a) : (b))
#endif

#define DUART_MAX_LINE 2
char sb1250_duart_present[DUART_MAX_LINE] = {1,1};

/*
 * Still not sure what the termios structures set up here are for, 
 *  but we have to supply pointers to them to register the tty driver
 */
static struct tty_driver *sb1250_duart_driver; //, sb1250_duart_callout_driver;

/*
 * This lock protects both the open flags for all the uart states as 
 * well as the reference count for the module
 */
static spinlock_t          open_lock = SPIN_LOCK_UNLOCKED;

typedef struct { 
        unsigned char       outp_buf[SERIAL_XMIT_SIZE];
        unsigned int        outp_head;
        unsigned int        outp_tail;
        unsigned int        outp_count;
        spinlock_t          outp_lock;
        unsigned int        open;
        unsigned int        line;
        unsigned int        last_cflags;
        unsigned long       flags;
        struct tty_struct   *tty;
        /* CSR addresses */
        u32                 *status;
        u32                 *imr;
        u32                 *tx_hold;
        u32                 *rx_hold;
        u32                 *mode_1;
        u32                 *mode_2;
        u32                 *clk_sel;
        u32                 *cmd;
} uart_state_t;

static uart_state_t uart_states[DUART_MAX_LINE];

/*
 * Inline functions local to this module 
 */

/*
 * In bug 1956, we get glitches that can mess up uart registers.  This
 * "write-mode-1 after any register access" is the accepted
 * workaround.
 */
#if SIBYTE_1956_WAR
static unsigned int last_mode1[DUART_MAX_LINE];
#endif

static inline u32 READ_SERCSR(u32 *addr, int line)
{
        u32 val = csr_in32(addr);
#if SIBYTE_1956_WAR
        csr_out32(last_mode1[line], uart_states[line].mode_1);
#endif
        return val;
}

static inline void WRITE_SERCSR(u32 val, u32 *addr, int line)
{
        csr_out32(val, addr);
#if SIBYTE_1956_WAR
        csr_out32(last_mode1[line], uart_states[line].mode_1);
#endif
}

static void init_duart_port(uart_state_t *port, int line)
{
        if (!(port->flags & DUART_INITIALIZED)) {
                port->line = line;
                port->status = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_STATUS));
                port->imr = (u32 *)(IO_SPACE_BASE | A_DUART_IMRREG(line));
                port->tx_hold = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_TX_HOLD));
                port->rx_hold = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_RX_HOLD));
                port->mode_1 = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_MODE_REG_1));
                port->mode_2 = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_MODE_REG_2));
                port->clk_sel = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_CLK_SEL));
                port->cmd = (u32 *)(IO_SPACE_BASE | A_DUART_CHANREG(line, R_DUART_CMD));
                port->flags |= DUART_INITIALIZED;
        }
}

/*
 * Mask out the passed interrupt lines at the duart level.  This should be
 * called while holding the associated outp_lock.
 */
static inline void duart_mask_ints(unsigned int line, unsigned int mask)
{
        uart_state_t *port = uart_states + line;
        u64 tmp = READ_SERCSR(port->imr, line);
        WRITE_SERCSR(tmp & ~mask, port->imr, line);
}

        
/* Unmask the passed interrupt lines at the duart level */
static inline void duart_unmask_ints(unsigned int line, unsigned int mask)
{
        uart_state_t *port = uart_states + line;
        u64 tmp = READ_SERCSR(port->imr, line);
        WRITE_SERCSR(tmp | mask, port->imr, line);
}

static inline void transmit_char_pio(uart_state_t *us)
{
        struct tty_struct *tty = us->tty;
        int blocked = 0;

        if (spin_trylock(&us->outp_lock)) {
                for (;;) {
                        if (!(READ_SERCSR(us->status, us->line) & M_DUART_TX_RDY))
                                break;
                        if (us->outp_count <= 0 || tty->stopped || tty->hw_stopped) {
                                break;
                        } else {
                                WRITE_SERCSR(us->outp_buf[us->outp_head],
                                             us->tx_hold, us->line);
                                us->outp_head = (us->outp_head + 1) & (SERIAL_XMIT_SIZE-1);
                                if (--us->outp_count <= 0)
                                        break;
                        }
                        udelay(10);
                }
                spin_unlock(&us->outp_lock);
        } else {
                blocked = 1;
        }

        if (!us->outp_count || tty->stopped ||
            tty->hw_stopped || blocked) {
                us->flags &= ~TX_INTEN;
                duart_mask_ints(us->line, M_DUART_IMR_TX);
        }

        if (us->open &&
            (us->outp_count < (SERIAL_XMIT_SIZE/2))) {
                /*
                 * We told the discipline at one point that we had no
                 * space, so it went to sleep.  Wake it up when we hit
                 * half empty
                 */
                if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
                    tty->ldisc.write_wakeup)
                        tty->ldisc.write_wakeup(tty);
                wake_up_interruptible(&tty->write_wait);
        }
}

/* 
 * Generic interrupt handler for both channels.  dev_id is a pointer
 * to the proper uart_states structure, so from that we can derive 
 * which port interrupted 
 */

static irqreturn_t duart_int(int irq, void *dev_id, struct pt_regs *regs)
{
        uart_state_t *us = (uart_state_t *)dev_id;
        struct tty_struct *tty = us->tty;
        unsigned int status = READ_SERCSR(us->status, us->line);

#ifdef DUART_SPEW
        printk("DUART INT\n");
#endif

        if (status & M_DUART_RX_RDY) {
                int counter = 2048;
                unsigned int ch;

                if (status & M_DUART_OVRUN_ERR)
                        tty_insert_flip_char(tty, 0, TTY_OVERRUN);
                if (status & M_DUART_PARITY_ERR) {
                        printk("Parity error!\n");
                } else if (status & M_DUART_FRM_ERR) {
                        printk("Frame error!\n");
                }

                while (counter > 0) {
                        if (!(READ_SERCSR(us->status, us->line) & M_DUART_RX_RDY))
                                break;
                        ch = READ_SERCSR(us->rx_hold, us->line);
                        if (tty->flip.count < TTY_FLIPBUF_SIZE) {
                                *tty->flip.char_buf_ptr++ = ch;
                                *tty->flip.flag_buf_ptr++ = 0;
                                tty->flip.count++;
                        }
                        udelay(1);
                        counter--;
                }
                tty_flip_buffer_push(tty);
        }

        if (status & M_DUART_TX_RDY) {
                transmit_char_pio(us);
        }

        return IRQ_HANDLED;
}

/*
 *  Actual driver functions
 */

/* Return the number of characters we can accomodate in a write at this instant */
static int duart_write_room(struct tty_struct *tty)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;
        int retval;

        retval = SERIAL_XMIT_SIZE - us->outp_count;

#ifdef DUART_SPEW
        printk("duart_write_room called, returning %i\n", retval);
#endif

        return retval;
}

/* memcpy the data from src to destination, but take extra care if the
   data is coming from user space */
static inline int copy_buf(char *dest, const char *src, int size, int from_user) 
{
        if (from_user) {
                (void) copy_from_user(dest, src, size); 
        } else {
                memcpy(dest, src, size);
        }
        return size;
}

/*
 * Buffer up to count characters from buf to be written.  If we don't have
 * other characters buffered, enable the tx interrupt to start sending
 */
static int duart_write(struct tty_struct * tty, int from_user,
        const unsigned char *buf, int count)
{
        uart_state_t *us;
        int c, t, total = 0;
        unsigned long flags;

        if (!tty) return 0;

        us = tty->driver_data;
        if (!us) return 0;

#ifdef DUART_SPEW
        printk("duart_write called for %i chars by %i (%s)\n", count, current->pid, current->comm);
#endif

        spin_lock_irqsave(&us->outp_lock, flags);

        for (;;) {
                c = count;

                t = SERIAL_XMIT_SIZE - us->outp_tail;
                if (t < c) c = t;

                t = SERIAL_XMIT_SIZE - 1 - us->outp_count;
                if (t < c) c = t;

                if (c <= 0) break;

                if (from_user) {
                        if (copy_from_user(us->outp_buf + us->outp_tail, buf, c)) {
                                spin_unlock_irqrestore(&us->outp_lock, flags);
                                return -EFAULT;
                        }
                } else {
                        memcpy(us->outp_buf + us->outp_tail, buf, c);
                }

                us->outp_count += c;
                us->outp_tail = (us->outp_tail + c) & (SERIAL_XMIT_SIZE - 1);
                buf += c;
                count -= c;
                total += c;
        }

        spin_unlock_irqrestore(&us->outp_lock, flags);

        if (us->outp_count && !tty->stopped && 
            !tty->hw_stopped && !(us->flags & TX_INTEN)) {
                us->flags |= TX_INTEN;
                duart_unmask_ints(us->line, M_DUART_IMR_TX);
        }

        return total;
}


/* Buffer one character to be written.  If there's not room for it, just drop
   it on the floor.  This is used for echo, among other things */
static void duart_put_char(struct tty_struct *tty, u_char ch)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;
        unsigned long flags;

#ifdef DUART_SPEW
        printk("duart_put_char called.  Char is %x (%c)\n", (int)ch, ch);
#endif

        spin_lock_irqsave(&us->outp_lock, flags);

        if (us->outp_count >= SERIAL_XMIT_SIZE - 1) {
                spin_unlock_irqrestore(&us->outp_lock, flags);
                return;
        }

        us->outp_buf[us->outp_tail] = ch;
        us->outp_tail = (us->outp_tail + 1) &(SERIAL_XMIT_SIZE-1);
        us->outp_count++;

        spin_unlock_irqrestore(&us->outp_lock, flags);
}

static void duart_flush_chars(struct tty_struct * tty)
{
        uart_state_t *port;

        if (!tty) return;

        port = tty->driver_data;

        if (!port) return;

        if (port->outp_count <= 0 || tty->stopped || tty->hw_stopped) {
                return;
        }

        port->flags |= TX_INTEN;
        duart_unmask_ints(port->line, M_DUART_IMR_TX);
}

/* Return the number of characters in the output buffer that have yet to be 
   written */
static int duart_chars_in_buffer(struct tty_struct *tty)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;
        int retval;

        retval = us->outp_count;

#ifdef DUART_SPEW
        printk("duart_chars_in_buffer returning %i\n", retval);
#endif
        return retval;
}

/* Kill everything we haven't yet shoved into the FIFO.  Turn off the
   transmit interrupt since we've nothing more to transmit */
static void duart_flush_buffer(struct tty_struct *tty)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;
        unsigned long flags;

#ifdef DUART_SPEW
        printk("duart_flush_buffer called\n");
#endif
        spin_lock_irqsave(&us->outp_lock, flags);
        us->outp_head = us->outp_tail = us->outp_count = 0;
        spin_unlock_irqrestore(&us->outp_lock, flags);

        wake_up_interruptible(&us->tty->write_wait);
        if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
            tty->ldisc.write_wakeup)
                tty->ldisc.write_wakeup(tty);
}


/* See sb1250 user manual for details on these registers */
static inline void duart_set_cflag(unsigned int line, unsigned int cflag)
{
        unsigned int mode_reg1 = 0, mode_reg2 = 0;
        unsigned int clk_divisor;
        uart_state_t *port = uart_states + line;

        switch (cflag & CSIZE) {
        case CS7:
                mode_reg1 |= V_DUART_BITS_PER_CHAR_7;
                
        default:
                /* We don't handle CS5 or CS6...is there a way we're supposed to flag this? 
                   right now we just force them to CS8 */
                mode_reg1 |= 0x0;
                break;
        }
        if (cflag & CSTOPB) {
                mode_reg2 |= M_DUART_STOP_BIT_LEN_2;
        }
        if (!(cflag & PARENB)) {
                mode_reg1 |= V_DUART_PARITY_MODE_NONE;
        }
        if (cflag & PARODD) {
                mode_reg1 |= M_DUART_PARITY_TYPE_ODD;
        }
        
        /* Formula for this is (5000000/baud)-1, but we saturate
           at 12 bits, which means we can't actually do anything less
           that 1200 baud */
        switch (cflag & CBAUD) {
        case B200:      
        case B300:      
        case B1200:     clk_divisor = 4095;             break;
        case B1800:     clk_divisor = 2776;             break;
        case B2400:     clk_divisor = 2082;             break;
        case B4800:     clk_divisor = 1040;             break;
        default:
        case B9600:     clk_divisor = 519;              break;
        case B19200:    clk_divisor = 259;              break;
        case B38400:    clk_divisor = 129;              break;
        case B57600:    clk_divisor = 85;               break;
        case B115200:   clk_divisor = 42;               break;
        }
        WRITE_SERCSR(mode_reg1, port->mode_1, port->line);
        WRITE_SERCSR(mode_reg2, port->mode_2, port->line);
        WRITE_SERCSR(clk_divisor, port->clk_sel, port->line);
        port->last_cflags = cflag;
}


/* Handle notification of a termios change.  */
static void duart_set_termios(struct tty_struct *tty, struct termios *old)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;

#ifdef DUART_SPEW 
        printk("duart_set_termios called by %i (%s)\n", current->pid, current->comm);
#endif
        if (old && tty->termios->c_cflag == old->c_cflag)
                return;
        duart_set_cflag(us->line, tty->termios->c_cflag);
}

static int duart_ioctl(struct tty_struct *tty, struct file * file,
                       unsigned int cmd, unsigned long arg)
{
/*      if (serial_paranoia_check(info, tty->device, "rs_ioctl"))
        return -ENODEV;*/
        switch (cmd) {
        case TIOCMGET:
                printk("Ignoring TIOCMGET\n");
                break;
        case TIOCMBIS:
                printk("Ignoring TIOCMBIS\n");
                break;
        case TIOCMBIC:
                printk("Ignoring TIOCMBIC\n");
                break;
        case TIOCMSET:
                printk("Ignoring TIOCMSET\n");
                break;
        case TIOCGSERIAL:
                printk("Ignoring TIOCGSERIAL\n");
                break;
        case TIOCSSERIAL:
                printk("Ignoring TIOCSSERIAL\n");
                break;
        case TIOCSERCONFIG:
                printk("Ignoring TIOCSERCONFIG\n");
                break;
        case TIOCSERGETLSR: /* Get line status register */
                printk("Ignoring TIOCSERGETLSR\n");
                break;
        case TIOCSERGSTRUCT:
                printk("Ignoring TIOCSERGSTRUCT\n");
                break;
        case TIOCMIWAIT:
                printk("Ignoring TIOCMIWAIT\n");
                break;
        case TIOCGICOUNT:
                printk("Ignoring TIOCGICOUNT\n");
                break;
        case TIOCSERGWILD:
                printk("Ignoring TIOCSERGWILD\n");
                break;
        case TIOCSERSWILD:
                printk("Ignoring TIOCSERSWILD\n");
                break;
        default:
                break;
        }
//      printk("Ignoring IOCTL %x from pid %i (%s)\n", cmd, current->pid, current->comm);
        return -ENOIOCTLCMD;
#if 0
        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:
        case TIOCMBIS:
        case TIOCMBIC:
        case TIOCMSET:
        case TIOCGSERIAL:
        case TIOCSSERIAL:
        case TIOCSERCONFIG:
        case TIOCSERGETLSR: /* Get line status register */
        case TIOCSERGSTRUCT:
        case TIOCMIWAIT:
        case TIOCGICOUNT:
        case TIOCSERGWILD:
        case TIOCSERSWILD:
                /* XXX Implement me! */
                printk("IOCTL needs implementing: %x\n", cmd);
                
        default:
                printk("Unknown ioctl: %x\n", cmd);
        }
#endif
        return 0;
}

/* XXXKW locking? */
static void duart_start(struct tty_struct *tty)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;

#ifdef DUART_SPEW
        printk("duart_start called\n");
#endif

        if (us->outp_count && !(us->flags & TX_INTEN)) {
                us->flags |= TX_INTEN;
                duart_unmask_ints(us->line, M_DUART_IMR_TX);
        }
}

/* XXXKW locking? */
static void duart_stop(struct tty_struct *tty)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;

#ifdef DUART_SPEW
        printk("duart_stop called\n");
#endif

        if (us->outp_count && (us->flags & TX_INTEN)) {
                us->flags &= ~TX_INTEN;
                duart_mask_ints(us->line, M_DUART_IMR_TX);
        }
}

/* Not sure on the semantics of this; are we supposed to wait until the stuff
   already in the hardware FIFO drains, or are we supposed to wait until 
   we've drained the output buffer, too?  I'm assuming the former, 'cause thats
   what the other drivers seem to assume 
*/

static void duart_wait_until_sent(struct tty_struct *tty, int timeout)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;
        unsigned long orig_jiffies;

        orig_jiffies = jiffies;
#ifdef DUART_SPEW
        printk("duart_wait_until_sent(%d)+\n", timeout);
#endif
        while (!(READ_SERCSR(us->status, us->line) & M_DUART_TX_EMT)) {
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(1);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
        }
#ifdef DUART_SPEW
        printk("duart_wait_until_sent()-\n");
#endif
}

/*
 * duart_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
static void duart_hangup(struct tty_struct *tty)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;

        duart_flush_buffer(tty);
        us->open = 0;
        us->tty = 0;
}

/*
 * Open a tty line.  Note that this can be called multiple times, so ->open can
 * be >1.  Only set up the tty struct if this is a "new" open, e.g. ->open was
 * zero
 */
static int duart_open(struct tty_struct *tty, struct file *filp)
{
        uart_state_t *us;
        unsigned int line = tty->index;
        unsigned long flags;

        MOD_INC_USE_COUNT;

        if ((line >= tty->driver->num) || !sb1250_duart_present[line]) {
                MOD_DEC_USE_COUNT;
                return -ENODEV;
        }

#ifdef DUART_SPEW
        printk("duart_open called by %i (%s), tty is %p, rw is %p, ww is %p\n",
               current->pid, current->comm, tty, tty->read_wait,
               tty->write_wait);
#endif

        us = uart_states + line;
        tty->driver_data = us;

        spin_lock_irqsave(&open_lock, flags);
        if (!us->open) {
                us->tty = tty;
                us->tty->termios->c_cflag = us->last_cflags;
        }
        us->open++;
        us->flags &= ~TX_INTEN;
        duart_unmask_ints(line, M_DUART_IMR_RX);
        spin_unlock_irqrestore(&open_lock, flags);

        return 0;
}


/*
 * Close a reference count out.  If reference count hits zero, null the
 * tty, kill the interrupts.  The tty_io driver is responsible for making
 * sure we've cleared out our internal buffers before calling close()
 */
static void duart_close(struct tty_struct *tty, struct file *filp)
{
        uart_state_t *us = (uart_state_t *) tty->driver_data;
        unsigned long flags;

#ifdef DUART_SPEW
        printk("duart_close called by %i (%s)\n", current->pid, current->comm);
#endif

        if (!us || !us->open)
                return;

        spin_lock_irqsave(&open_lock, flags);
        if (tty_hung_up_p(filp)) {
                MOD_DEC_USE_COUNT;
                spin_unlock_irqrestore(&open_lock, flags);
                return;
        }

        if (--us->open < 0) {
                us->open = 0;
                printk(KERN_ERR "duart: bad open count: %d\n", us->open);
        }
        if (us->open) {
                spin_unlock_irqrestore(&open_lock, flags);
                return;
        }

        spin_unlock_irqrestore(&open_lock, flags);

        tty->closing = 1;

        /* Stop accepting input */
        duart_mask_ints(us->line, M_DUART_IMR_RX);
        /* Wait for FIFO to drain */
        while (!(READ_SERCSR(us->status, us->line) & M_DUART_TX_EMT))
                ;

        if (tty->driver->flush_buffer)
                tty->driver->flush_buffer(tty);
        if (tty->ldisc.flush_buffer)
                tty->ldisc.flush_buffer(tty);
        tty->closing = 0;

        MOD_DEC_USE_COUNT;
}


static struct tty_operations duart_ops = {
        .open   = duart_open,
        .close = duart_close,
        .write = duart_write,
        .put_char = duart_put_char,
        .flush_chars = duart_flush_chars,
        .write_room = duart_write_room,
        .chars_in_buffer = duart_chars_in_buffer,
        .flush_buffer = duart_flush_buffer,
        .ioctl = duart_ioctl,
//        .throttle = duart_throttle,
//        .unthrottle = duart_unthrottle,
        .set_termios = duart_set_termios,
        .stop = duart_stop,
        .start = duart_start,
        .hangup = duart_hangup,
        .wait_until_sent = duart_wait_until_sent,
};

/* Set up the driver and register it, register the 2 1250 UART interrupts.  This
   is called from tty_init, or as a part of the module init */
static int __init sb1250_duart_init(void) 
{
        int i;

        sb1250_duart_driver = alloc_tty_driver(DUART_MAX_LINE);
        if (!sb1250_duart_driver)
                return -ENOMEM;

        sb1250_duart_driver->owner = THIS_MODULE;
        sb1250_duart_driver->name = "duart";
        sb1250_duart_driver->devfs_name = "duart/";
        sb1250_duart_driver->major = TTY_MAJOR;
        sb1250_duart_driver->minor_start = SB1250_DUART_MINOR_BASE;
        sb1250_duart_driver->type            = TTY_DRIVER_TYPE_SERIAL;
        sb1250_duart_driver->subtype         = SERIAL_TYPE_NORMAL;
        sb1250_duart_driver->init_termios    = tty_std_termios;
        sb1250_duart_driver->flags           = TTY_DRIVER_REAL_RAW;
        tty_set_operations(sb1250_duart_driver, &duart_ops);

        for (i=0; i<DUART_MAX_LINE; i++) {
                uart_state_t *port = uart_states + i;

                if (!sb1250_duart_present[i])
                        continue;

                init_duart_port(port, i);
                spin_lock_init(&port->outp_lock);
                duart_mask_ints(i, M_DUART_IMR_ALL);
                if (request_irq(K_INT_UART_0+i, duart_int, 0, "uart", port)) {
                        panic("Couldn't get uart0 interrupt line");
                }
                __raw_writeq(M_DUART_RX_EN|M_DUART_TX_EN,
                      IO_SPACE_BASE | A_DUART_CHANREG(i, R_DUART_CMD));
                duart_set_cflag(i, DEFAULT_CFLAGS);
        }

        /* Interrupts are now active, our ISR can be called. */

        if (tty_register_driver(sb1250_duart_driver)) {
                printk(KERN_ERR "Couldn't register sb1250 duart serial driver\n");
                put_tty_driver(sb1250_duart_driver);
                return 1;
        }
        return 0;
}

/* Unload the driver.  Unregister stuff, get ready to go away */
static void __exit sb1250_duart_fini(void)
{
        unsigned long flags;
        int i;

        local_irq_save(flags);
        tty_unregister_driver(sb1250_duart_driver);
        put_tty_driver(sb1250_duart_driver);

        for (i=0; i<DUART_MAX_LINE; i++) {
                if (!sb1250_duart_present[i])
                        continue;
                free_irq(K_INT_UART_0+i, &uart_states[i]);
                disable_irq(K_INT_UART_0+i);
        }
        local_irq_restore(flags);
}

module_init(sb1250_duart_init);
module_exit(sb1250_duart_fini);
MODULE_DESCRIPTION("SB1250 Duart serial driver");
MODULE_AUTHOR("Justin Carlson, Broadcom Corp.");

#ifdef CONFIG_SIBYTE_SB1250_DUART_CONSOLE

/*
 * Serial console stuff.  Very basic, polling driver for doing serial
 * console output.  The console_sem is held by the caller, so we
 * shouldn't be interrupted for more console activity.
 * XXXKW What about getting interrupted by uart driver activity?
 */

void serial_outc(unsigned char c, int line)
{
        uart_state_t *port = uart_states + line;
        while (!(READ_SERCSR(port->status, line) & M_DUART_TX_RDY)) ;
        WRITE_SERCSR(c, port->tx_hold, line);
        while (!(READ_SERCSR(port->status, port->line) & M_DUART_TX_EMT)) ;
}

static void ser_console_write(struct console *cons, const char *s,
        unsigned int count)
{
        int line = cons->index;
        uart_state_t *port = uart_states + line;
        u32 imr;

        imr = READ_SERCSR(port->imr, line);
        WRITE_SERCSR(0, port->imr, line);
        while (count--) {
                if (*s == '\n')
                        serial_outc('\r', line);
                serial_outc(*s++, line);
        }
        WRITE_SERCSR(imr, port->imr, line);
}

static struct tty_driver *ser_console_device(struct console *c, int *index)
{
        *index = c->index;
        return sb1250_duart_driver;
}

static int ser_console_setup(struct console *cons, char *str)
{
        int i;

        for (i=0; i<DUART_MAX_LINE; i++) {
                uart_state_t *port = uart_states + i;

                if (!sb1250_duart_present[i])
                        continue;

                init_duart_port(port, i);
#if SIBYTE_1956_WAR
                last_mode1[i] = V_DUART_PARITY_MODE_NONE|V_DUART_BITS_PER_CHAR_8;
#endif
                WRITE_SERCSR(V_DUART_PARITY_MODE_NONE|V_DUART_BITS_PER_CHAR_8,
                             port->mode_1, i);
                WRITE_SERCSR(M_DUART_STOP_BIT_LEN_1,
                             port->mode_2, i);
                WRITE_SERCSR(V_DUART_BAUD_RATE(115200),
                             port->clk_sel, i);
        }
        return 0;
}

static struct console sb1250_ser_cons = {
        name:           "duart",
        write:          ser_console_write,
        device:         ser_console_device,
        setup:          ser_console_setup,
        flags:          CON_PRINTBUFFER,
        index:          -1,
};

static int __init sb1250_serial_console_init(void)
{
        register_console(&sb1250_ser_cons);
        return 0;
}

console_initcall(sb1250_serial_console_init);

#endif /* CONFIG_SIBYTE_SB1250_DUART_CONSOLE */