[PATCH] bcm43xx: fix pctl slowclock limit calculation

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / serial / 68328serial.c

/* 68328serial.c: Serial port driver for 68328 microcontroller
 *
 * Copyright (C) 1995       David S. Miller    <davem@caip.rutgers.edu>
 * Copyright (C) 1998       Kenneth Albanowski <kjahds@kjahds.com>
 * Copyright (C) 1998, 1999 D. Jeff Dionne     <jeff@uclinux.org>
 * Copyright (C) 1999       Vladimir Gurevich  <vgurevic@cisco.com>
 * Copyright (C) 2002-2003  David McCullough   <davidm@snapgear.com>
 * Copyright (C) 2002       Greg Ungerer       <gerg@snapgear.com>
 *
 * VZ Support/Fixes             Evan Stawnyczy <e@lineo.ca>
 * Multiple UART support        Daniel Potts <danielp@cse.unsw.edu.au>
 * Power management support     Daniel Potts <danielp@cse.unsw.edu.au>
 * VZ Second Serial Port enable Phil Wilshire
 * 2.4/2.5 port                 David McCullough
 */

#include <asm/dbg.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/config.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/reboot.h>
#include <linux/keyboard.h>
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/pm_legacy.h>
#include <linux/bitops.h>
#include <linux/delay.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/uaccess.h>

/* (es) */
/* note: perhaps we can murge these files, so that you can just
 *       define 1 of them, and they can sort that out for themselves
 */
#if defined(CONFIG_M68EZ328)
#include <asm/MC68EZ328.h>
#else
#if defined(CONFIG_M68VZ328)
#include <asm/MC68VZ328.h>
#else
#include <asm/MC68328.h>
#endif /* CONFIG_M68VZ328 */
#endif /* CONFIG_M68EZ328 */

#include "68328serial.h"

/* Turn off usage of real serial interrupt code, to "support" Copilot */
#ifdef CONFIG_XCOPILOT_BUGS
#undef USE_INTS
#else
#define USE_INTS
#endif

static struct m68k_serial m68k_soft[NR_PORTS];
struct m68k_serial *IRQ_ports[NR_IRQS];

static unsigned int uart_irqs[NR_PORTS] = UART_IRQ_DEFNS;

/* multiple ports are contiguous in memory */
m68328_uart *uart_addr = (m68328_uart *)USTCNT_ADDR;

struct tty_struct m68k_ttys;
struct m68k_serial *m68k_consinfo = 0;

#define M68K_CLOCK (16667000) /* FIXME: 16MHz is likely wrong */

#ifdef CONFIG_CONSOLE
extern wait_queue_head_t keypress_wait; 
#endif

struct tty_driver *serial_driver;

/* serial subtype definitions */
#define SERIAL_TYPE_NORMAL      1
 
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS 256

/* Debugging... DEBUG_INTR is bad to use when one of the zs
 * lines is your console ;(
 */
#undef SERIAL_DEBUG_INTR
#undef SERIAL_DEBUG_OPEN
#undef SERIAL_DEBUG_FLOW

#define RS_ISR_PASS_LIMIT 256

static void change_speed(struct m68k_serial *info);

/*
 *      Setup for console. Argument comes from the boot command line.
 */

#if defined(CONFIG_M68EZ328ADS) || defined(CONFIG_ALMA_ANS) || defined(CONFIG_DRAGONIXVZ)
#define CONSOLE_BAUD_RATE       115200
#define DEFAULT_CBAUD           B115200
#else
        /* (es) */
        /* note: this is messy, but it works, again, perhaps defined somewhere else?*/
        #ifdef CONFIG_M68VZ328
        #define CONSOLE_BAUD_RATE       19200
        #define DEFAULT_CBAUD           B19200
        #endif
        /* (/es) */
#endif

#ifndef CONSOLE_BAUD_RATE
#define CONSOLE_BAUD_RATE       9600
#define DEFAULT_CBAUD           B9600
#endif


static int m68328_console_initted = 0;
static int m68328_console_baud    = CONSOLE_BAUD_RATE;
static int m68328_console_cbaud   = DEFAULT_CBAUD;


/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the memcpy_fromfs blocks while swapping in a page,
 * and some other program tries to do a serial write at the same time.
 * Since the lock will only come under contention when the system is
 * swapping and available memory is low, it makes sense to share one
 * buffer across all the serial ports, since it significantly saves
 * memory if large numbers of serial ports are open.
 */
static unsigned char tmp_buf[SERIAL_XMIT_SIZE]; /* This is cheating */

static inline int serial_paranoia_check(struct m68k_serial *info,
                                        char *name, const char *routine)
{
#ifdef SERIAL_PARANOIA_CHECK
        static const char *badmagic =
                "Warning: bad magic number for serial struct %s in %s\n";
        static const char *badinfo =
                "Warning: null m68k_serial for %s in %s\n";

        if (!info) {
                printk(badinfo, name, routine);
                return 1;
        }
        if (info->magic != SERIAL_MAGIC) {
                printk(badmagic, name, routine);
                return 1;
        }
#endif
        return 0;
}

/*
 * This is used to figure out the divisor speeds and the timeouts
 */
static int baud_table[] = {
        0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
        9600, 19200, 38400, 57600, 115200, 0 };

#define BAUD_TABLE_SIZE (sizeof(baud_table)/sizeof(baud_table[0]))

/* Sets or clears DTR/RTS on the requested line */
static inline void m68k_rtsdtr(struct m68k_serial *ss, int set)
{
        if (set) {
                /* set the RTS/CTS line */
        } else {
                /* clear it */
        }
        return;
}

/* Utility routines */
static inline int get_baud(struct m68k_serial *ss)
{
        unsigned long result = 115200;
        unsigned short int baud = uart_addr[ss->line].ubaud;
        if (GET_FIELD(baud, UBAUD_PRESCALER) == 0x38) result = 38400;
        result >>= GET_FIELD(baud, UBAUD_DIVIDE);

        return result;
}

/*
 * ------------------------------------------------------------
 * rs_stop() and rs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 * ------------------------------------------------------------
 */
static void rs_stop(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;

        if (serial_paranoia_check(info, tty->name, "rs_stop"))
                return;
        
        save_flags(flags); cli();
        uart->ustcnt &= ~USTCNT_TXEN;
        restore_flags(flags);
}

static void rs_put_char(char ch)
{
        int flags, loops = 0;

        save_flags(flags); cli();

        while (!(UTX & UTX_TX_AVAIL) && (loops < 1000)) {
                loops++;
                udelay(5);
        }

        UTX_TXDATA = ch;
        udelay(5);
        restore_flags(flags);
}

static void rs_start(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;
        
        if (serial_paranoia_check(info, tty->name, "rs_start"))
                return;
        
        save_flags(flags); cli();
        if (info->xmit_cnt && info->xmit_buf && !(uart->ustcnt & USTCNT_TXEN)) {
#ifdef USE_INTS
                uart->ustcnt |= USTCNT_TXEN | USTCNT_TX_INTR_MASK;
#else
                uart->ustcnt |= USTCNT_TXEN;
#endif
        }
        restore_flags(flags);
}

/* Drop into either the boot monitor or kadb upon receiving a break
 * from keyboard/console input.
 */
static void batten_down_hatches(void)
{
        /* Drop into the debugger */
}

static void status_handle(struct m68k_serial *info, unsigned short status)
{
#if 0
        if(status & DCD) {
                if((info->tty->termios->c_cflag & CRTSCTS) &&
                   ((info->curregs[3] & AUTO_ENAB)==0)) {
                        info->curregs[3] |= AUTO_ENAB;
                        info->pendregs[3] |= AUTO_ENAB;
                        write_zsreg(info->m68k_channel, 3, info->curregs[3]);
                }
        } else {
                if((info->curregs[3] & AUTO_ENAB)) {
                        info->curregs[3] &= ~AUTO_ENAB;
                        info->pendregs[3] &= ~AUTO_ENAB;
                        write_zsreg(info->m68k_channel, 3, info->curregs[3]);
                }
        }
#endif
        /* If this is console input and this is a
         * 'break asserted' status change interrupt
         * see if we can drop into the debugger
         */
        if((status & URX_BREAK) && info->break_abort)
                batten_down_hatches();
        return;
}

static void receive_chars(struct m68k_serial *info, struct pt_regs *regs,
                          unsigned short rx)
{
        struct tty_struct *tty = info->tty;
        m68328_uart *uart = &uart_addr[info->line];
        unsigned char ch, flag;

        /*
         * This do { } while() loop will get ALL chars out of Rx FIFO 
         */
#ifndef CONFIG_XCOPILOT_BUGS
        do {
#endif  
                ch = GET_FIELD(rx, URX_RXDATA);
        
                if(info->is_cons) {
                        if(URX_BREAK & rx) { /* whee, break received */
                                status_handle(info, rx);
                                return;
#ifdef CONFIG_MAGIC_SYSRQ
                        } else if (ch == 0x10) { /* ^P */
                                show_state();
                                show_free_areas();
                                show_buffers();
/*                              show_net_buffers(); */
                                return;
                        } else if (ch == 0x12) { /* ^R */
                                emergency_restart();
                                return;
#endif /* CONFIG_MAGIC_SYSRQ */
                        }
                        /* It is a 'keyboard interrupt' ;-) */
#ifdef CONFIG_CONSOLE
                        wake_up(&keypress_wait);
#endif                  
                }

                if(!tty)
                        goto clear_and_exit;
                
                /*
                 * Make sure that we do not overflow the buffer
                 */
                if (tty_request_buffer_room(tty, 1) == 0) {
                        tty_schedule_flip(tty);
                        return;
                }

                flag = TTY_NORMAL;

                if(rx & URX_PARITY_ERROR) {
                        flag = TTY_PARITY;
                        status_handle(info, rx);
                } else if(rx & URX_OVRUN) {
                        flag = TTY_OVERRUN;
                        status_handle(info, rx);
                } else if(rx & URX_FRAME_ERROR) {
                        flag = TTY_FRAME;
                        status_handle(info, rx);
                }
                tty_insert_flip_char(tty, ch, flag);
#ifndef CONFIG_XCOPILOT_BUGS
        } while((rx = uart->urx.w) & URX_DATA_READY);
#endif

        tty_schedule_flip(tty);

clear_and_exit:
        return;
}

static void transmit_chars(struct m68k_serial *info)
{
        m68328_uart *uart = &uart_addr[info->line];

        if (info->x_char) {
                /* Send next char */
                uart->utx.b.txdata = info->x_char;
                info->x_char = 0;
                goto clear_and_return;
        }

        if((info->xmit_cnt <= 0) || info->tty->stopped) {
                /* That's peculiar... TX ints off */
                uart->ustcnt &= ~USTCNT_TX_INTR_MASK;
                goto clear_and_return;
        }

        /* Send char */
        uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
        info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
        info->xmit_cnt--;

        if (info->xmit_cnt < WAKEUP_CHARS)
                schedule_work(&info->tqueue);

        if(info->xmit_cnt <= 0) {
                /* All done for now... TX ints off */
                uart->ustcnt &= ~USTCNT_TX_INTR_MASK;
                goto clear_and_return;
        }

clear_and_return:
        /* Clear interrupt (should be auto)*/
        return;
}

/*
 * This is the serial driver's generic interrupt routine
 */
irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        struct m68k_serial * info;
        m68328_uart *uart;
        unsigned short rx;
        unsigned short tx;

        info = IRQ_ports[irq];
        if(!info)
            return IRQ_NONE;

        uart = &uart_addr[info->line];
        rx = uart->urx.w;

#ifdef USE_INTS
        tx = uart->utx.w;

        if (rx & URX_DATA_READY) receive_chars(info, regs, rx);
        if (tx & UTX_TX_AVAIL)   transmit_chars(info);
#else
        receive_chars(info, regs, rx);          
#endif
        return IRQ_HANDLED;
}

static void do_softint(void *private)
{
        struct m68k_serial      *info = (struct m68k_serial *) private;
        struct tty_struct       *tty;
        
        tty = info->tty;
        if (!tty)
                return;
#if 0
        if (clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
                tty_wakeup(tty);
        }
#endif   
}

/*
 * This routine is called from the scheduler tqueue when the interrupt
 * routine has signalled that a hangup has occurred.  The path of
 * hangup processing is:
 *
 *      serial interrupt routine -> (scheduler tqueue) ->
 *      do_serial_hangup() -> tty->hangup() -> rs_hangup()
 * 
 */
static void do_serial_hangup(void *private)
{
        struct m68k_serial      *info = (struct m68k_serial *) private;
        struct tty_struct       *tty;
        
        tty = info->tty;
        if (!tty)
                return;

        tty_hangup(tty);
}


static int startup(struct m68k_serial * info)
{
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;
        
        if (info->flags & S_INITIALIZED)
                return 0;

        if (!info->xmit_buf) {
                info->xmit_buf = (unsigned char *) __get_free_page(GFP_KERNEL);
                if (!info->xmit_buf)
                        return -ENOMEM;
        }

        save_flags(flags); cli();

        /*
         * Clear the FIFO buffers and disable them
         * (they will be reenabled in change_speed())
         */

        uart->ustcnt = USTCNT_UEN;
        info->xmit_fifo_size = 1;
        uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | USTCNT_TXEN;
        (void)uart->urx.w;

        /*
         * Finally, enable sequencing and interrupts
         */
#ifdef USE_INTS
        uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | 
                 USTCNT_RX_INTR_MASK | USTCNT_TX_INTR_MASK;
#else
        uart->ustcnt = USTCNT_UEN | USTCNT_RXEN | USTCNT_RX_INTR_MASK;
#endif

        if (info->tty)
                clear_bit(TTY_IO_ERROR, &info->tty->flags);
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;

        /*
         * and set the speed of the serial port
         */

        change_speed(info);

        info->flags |= S_INITIALIZED;
        restore_flags(flags);
        return 0;
}

/*
 * 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 shutdown(struct m68k_serial * info)
{
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long   flags;

        uart->ustcnt = 0; /* All off! */
        if (!(info->flags & S_INITIALIZED))
                return;

        save_flags(flags); cli(); /* Disable interrupts */
        
        if (info->xmit_buf) {
                free_page((unsigned long) info->xmit_buf);
                info->xmit_buf = 0;
        }

        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);
        
        info->flags &= ~S_INITIALIZED;
        restore_flags(flags);
}

struct {
        int divisor, prescale;
}
#ifndef CONFIG_M68VZ328
 hw_baud_table[18] = {
        {0,0}, /* 0 */
        {0,0}, /* 50 */
        {0,0}, /* 75 */
        {0,0}, /* 110 */
        {0,0}, /* 134 */
        {0,0}, /* 150 */
        {0,0}, /* 200 */
        {7,0x26}, /* 300 */
        {6,0x26}, /* 600 */
        {5,0x26}, /* 1200 */
        {0,0}, /* 1800 */
        {4,0x26}, /* 2400 */
        {3,0x26}, /* 4800 */
        {2,0x26}, /* 9600 */
        {1,0x26}, /* 19200 */
        {0,0x26}, /* 38400 */
        {1,0x38}, /* 57600 */
        {0,0x38}, /* 115200 */
};
#else
 hw_baud_table[18] = {
                 {0,0}, /* 0 */
                 {0,0}, /* 50 */
                 {0,0}, /* 75 */
                 {0,0}, /* 110 */
                 {0,0}, /* 134 */
                 {0,0}, /* 150 */
                 {0,0}, /* 200 */
                 {0,0}, /* 300 */
                 {7,0x26}, /* 600 */
                 {6,0x26}, /* 1200 */
                 {0,0}, /* 1800 */
                 {5,0x26}, /* 2400 */
                 {4,0x26}, /* 4800 */
                 {3,0x26}, /* 9600 */
                 {2,0x26}, /* 19200 */
                 {1,0x26}, /* 38400 */
                 {0,0x26}, /* 57600 */
                 {1,0x38}, /* 115200 */
}; 
#endif
/* rate = 1036800 / ((65 - prescale) * (1<<divider)) */

/*
 * This routine is called to set the UART divisor registers to match
 * the specified baud rate for a serial port.
 */
static void change_speed(struct m68k_serial *info)
{
        m68328_uart *uart = &uart_addr[info->line];
        unsigned short port;
        unsigned short ustcnt;
        unsigned cflag;
        int     i;

        if (!info->tty || !info->tty->termios)
                return;
        cflag = info->tty->termios->c_cflag;
        if (!(port = info->port))
                return;

        ustcnt = uart->ustcnt;
        uart->ustcnt = ustcnt & ~USTCNT_TXEN;

        i = cflag & CBAUD;
        if (i & CBAUDEX) {
                i = (i & ~CBAUDEX) + B38400;
        }

        info->baud = baud_table[i];
        uart->ubaud = PUT_FIELD(UBAUD_DIVIDE,    hw_baud_table[i].divisor) | 
                PUT_FIELD(UBAUD_PRESCALER, hw_baud_table[i].prescale);

        ustcnt &= ~(USTCNT_PARITYEN | USTCNT_ODD_EVEN | USTCNT_STOP | USTCNT_8_7);
        
        if ((cflag & CSIZE) == CS8)
                ustcnt |= USTCNT_8_7;
                
        if (cflag & CSTOPB)
                ustcnt |= USTCNT_STOP;

        if (cflag & PARENB)
                ustcnt |= USTCNT_PARITYEN;
        if (cflag & PARODD)
                ustcnt |= USTCNT_ODD_EVEN;
        
#ifdef CONFIG_SERIAL_68328_RTS_CTS
        if (cflag & CRTSCTS) {
                uart->utx.w &= ~ UTX_NOCTS;
        } else {
                uart->utx.w |= UTX_NOCTS;
        }
#endif

        ustcnt |= USTCNT_TXEN;
        
        uart->ustcnt = ustcnt;
        return;
}

/*
 * Fair output driver allows a process to speak.
 */
static void rs_fair_output(void)
{
        int left;               /* Output no more than that */
        unsigned long flags;
        struct m68k_serial *info = &m68k_soft[0];
        char c;

        if (info == 0) return;
        if (info->xmit_buf == 0) return;

        save_flags(flags);  cli();
        left = info->xmit_cnt;
        while (left != 0) {
                c = info->xmit_buf[info->xmit_tail];
                info->xmit_tail = (info->xmit_tail+1) & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt--;
                restore_flags(flags);

                rs_put_char(c);

                save_flags(flags);  cli();
                left = min(info->xmit_cnt, left-1);
        }

        /* Last character is being transmitted now (hopefully). */
        udelay(5);

        restore_flags(flags);
        return;
}

/*
 * m68k_console_print is registered for printk.
 */
void console_print_68328(const char *p)
{
        char c;
        
        while((c=*(p++)) != 0) {
                if(c == '\n')
                        rs_put_char('\r');
                rs_put_char(c);
        }

        /* Comment this if you want to have a strict interrupt-driven output */
        rs_fair_output();

        return;
}

static void rs_set_ldisc(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

        if (serial_paranoia_check(info, tty->name, "rs_set_ldisc"))
                return;

        info->is_cons = (tty->termios->c_line == N_TTY);
        
        printk("ttyS%d console mode %s\n", info->line, info->is_cons ? "on" : "off");
}

static void rs_flush_chars(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;

        if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
                return;
#ifndef USE_INTS
        for(;;) {
#endif

        /* Enable transmitter */
        save_flags(flags); cli();

        if (info->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
                        !info->xmit_buf) {
                restore_flags(flags);
                return;
        }

#ifdef USE_INTS
        uart->ustcnt |= USTCNT_TXEN | USTCNT_TX_INTR_MASK;
#else
        uart->ustcnt |= USTCNT_TXEN;
#endif

#ifdef USE_INTS
        if (uart->utx.w & UTX_TX_AVAIL) {
#else
        if (1) {
#endif
                /* Send char */
                uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
                info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt--;
        }

#ifndef USE_INTS
        while (!(uart->utx.w & UTX_TX_AVAIL)) udelay(5);
        }
#endif
        restore_flags(flags);
}

extern void console_printn(const char * b, int count);

static int rs_write(struct tty_struct * tty,
                    const unsigned char *buf, int count)
{
        int     c, total = 0;
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;

        if (serial_paranoia_check(info, tty->name, "rs_write"))
                return 0;

        if (!tty || !info->xmit_buf)
                return 0;

        save_flags(flags);
        while (1) {
                cli();          
                c = min_t(int, count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
                                   SERIAL_XMIT_SIZE - info->xmit_head));
                if (c <= 0)
                        break;

                memcpy(info->xmit_buf + info->xmit_head, buf, c);
                info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
                info->xmit_cnt += c;
                restore_flags(flags);
                buf += c;
                count -= c;
                total += c;
        }

        if (info->xmit_cnt && !tty->stopped && !tty->hw_stopped) {
                /* Enable transmitter */
                cli();          
#ifndef USE_INTS
                while(info->xmit_cnt) {
#endif

                uart->ustcnt |= USTCNT_TXEN;
#ifdef USE_INTS
                uart->ustcnt |= USTCNT_TX_INTR_MASK;
#else
                while (!(uart->utx.w & UTX_TX_AVAIL)) udelay(5);
#endif
                if (uart->utx.w & UTX_TX_AVAIL) {
                        uart->utx.b.txdata = info->xmit_buf[info->xmit_tail++];
                        info->xmit_tail = info->xmit_tail & (SERIAL_XMIT_SIZE-1);
                        info->xmit_cnt--;
                }

#ifndef USE_INTS
                }
#endif
                restore_flags(flags);
        }
        restore_flags(flags);
        return total;
}

static int rs_write_room(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
        int     ret;
                                
        if (serial_paranoia_check(info, tty->name, "rs_write_room"))
                return 0;
        ret = SERIAL_XMIT_SIZE - info->xmit_cnt - 1;
        if (ret < 0)
                ret = 0;
        return ret;
}

static int rs_chars_in_buffer(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
                                
        if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
                return 0;
        return info->xmit_cnt;
}

static void rs_flush_buffer(struct tty_struct *tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
                                
        if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
                return;
        cli();
        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
        sti();
        tty_wakeup(tty);
}

/*
 * ------------------------------------------------------------
 * rs_throttle()
 * 
 * This routine is called by the upper-layer tty layer to signal that
 * incoming characters should be throttled.
 * ------------------------------------------------------------
 */
static void rs_throttle(struct tty_struct * tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

        if (serial_paranoia_check(info, tty->name, "rs_throttle"))
                return;
        
        if (I_IXOFF(tty))
                info->x_char = STOP_CHAR(tty);

        /* Turn off RTS line (do this atomic) */
}

static void rs_unthrottle(struct tty_struct * tty)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

        if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
                return;
        
        if (I_IXOFF(tty)) {
                if (info->x_char)
                        info->x_char = 0;
                else
                        info->x_char = START_CHAR(tty);
        }

        /* Assert RTS line (do this atomic) */
}

/*
 * ------------------------------------------------------------
 * rs_ioctl() and friends
 * ------------------------------------------------------------
 */

static int get_serial_info(struct m68k_serial * info,
                           struct serial_struct * retinfo)
{
        struct serial_struct tmp;
  
        if (!retinfo)
                return -EFAULT;
        memset(&tmp, 0, sizeof(tmp));
        tmp.type = info->type;
        tmp.line = info->line;
        tmp.port = info->port;
        tmp.irq = info->irq;
        tmp.flags = info->flags;
        tmp.baud_base = info->baud_base;
        tmp.close_delay = info->close_delay;
        tmp.closing_wait = info->closing_wait;
        tmp.custom_divisor = info->custom_divisor;
        copy_to_user(retinfo,&tmp,sizeof(*retinfo));
        return 0;
}

static int set_serial_info(struct m68k_serial * info,
                           struct serial_struct * new_info)
{
        struct serial_struct new_serial;
        struct m68k_serial old_info;
        int                     retval = 0;

        if (!new_info)
                return -EFAULT;
        copy_from_user(&new_serial,new_info,sizeof(new_serial));
        old_info = *info;

        if (!capable(CAP_SYS_ADMIN)) {
                if ((new_serial.baud_base != info->baud_base) ||
                    (new_serial.type != info->type) ||
                    (new_serial.close_delay != info->close_delay) ||
                    ((new_serial.flags & ~S_USR_MASK) !=
                     (info->flags & ~S_USR_MASK)))
                        return -EPERM;
                info->flags = ((info->flags & ~S_USR_MASK) |
                               (new_serial.flags & S_USR_MASK));
                info->custom_divisor = new_serial.custom_divisor;
                goto check_and_exit;
        }

        if (info->count > 1)
                return -EBUSY;

        /*
         * OK, past this point, all the error checking has been done.
         * At this point, we start making changes.....
         */

        info->baud_base = new_serial.baud_base;
        info->flags = ((info->flags & ~S_FLAGS) |
                        (new_serial.flags & S_FLAGS));
        info->type = new_serial.type;
        info->close_delay = new_serial.close_delay;
        info->closing_wait = new_serial.closing_wait;

check_and_exit:
        retval = startup(info);
        return retval;
}

/*
 * get_lsr_info - get line status register info
 *
 * 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 int get_lsr_info(struct m68k_serial * info, unsigned int *value)
{
#ifdef CONFIG_SERIAL_68328_RTS_CTS
        m68328_uart *uart = &uart_addr[info->line];
#endif
        unsigned char status;

        cli();
#ifdef CONFIG_SERIAL_68328_RTS_CTS
        status = (uart->utx.w & UTX_CTS_STAT) ? 1 : 0;
#else
        status = 0;
#endif
        sti();
        put_user(status,value);
        return 0;
}

/*
 * This routine sends a break character out the serial port.
 */
static void send_break(struct m68k_serial * info, unsigned int duration)
{
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;
        if (!info->port)
                return;
        save_flags(flags);
        cli();
#ifdef USE_INTS 
        uart->utx.w |= UTX_SEND_BREAK;
        msleep_interruptible(duration);
        uart->utx.w &= ~UTX_SEND_BREAK;
#endif          
        restore_flags(flags);
}

static int rs_ioctl(struct tty_struct *tty, struct file * file,
                    unsigned int cmd, unsigned long arg)
{
        int error;
        struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
        int retval;

        if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
                return -ENODEV;

        if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
            (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGWILD)  &&
            (cmd != TIOCSERSWILD) && (cmd != TIOCSERGSTRUCT)) {
                if (tty->flags & (1 << TTY_IO_ERROR))
                    return -EIO;
        }
        
        switch (cmd) {
                case TCSBRK:    /* SVID version: non-zero arg --> no break */
                        retval = tty_check_change(tty);
                        if (retval)
                                return retval;
                        tty_wait_until_sent(tty, 0);
                        if (!arg)
                                send_break(info, 250);  /* 1/4 second */
                        return 0;
                case TCSBRKP:   /* support for POSIX tcsendbreak() */
                        retval = tty_check_change(tty);
                        if (retval)
                                return retval;
                        tty_wait_until_sent(tty, 0);
                        send_break(info, arg ? arg*(100) : 250);
                        return 0;
                case TIOCGSOFTCAR:
                        error = put_user(C_CLOCAL(tty) ? 1 : 0,
                                    (unsigned long *) arg);
                        if (error)
                                return error;
                        return 0;
                case TIOCSSOFTCAR:
                        get_user(arg, (unsigned long *) arg);
                        tty->termios->c_cflag =
                                ((tty->termios->c_cflag & ~CLOCAL) |
                                 (arg ? CLOCAL : 0));
                        return 0;
                case TIOCGSERIAL:
                        if (access_ok(VERIFY_WRITE, (void *) arg,
                                                sizeof(struct serial_struct)))
                                return get_serial_info(info,
                                               (struct serial_struct *) arg);
                        return -EFAULT;
                case TIOCSSERIAL:
                        return set_serial_info(info,
                                               (struct serial_struct *) arg);
                case TIOCSERGETLSR: /* Get line status register */
                        if (access_ok(VERIFY_WRITE, (void *) arg,
                                                sizeof(unsigned int));
                                return get_lsr_info(info, (unsigned int *) arg);
                        return -EFAULT;
                case TIOCSERGSTRUCT:
                        if (!access_ok(VERIFY_WRITE, (void *) arg,
                                                sizeof(struct m68k_serial)))
                                return -EFAULT;
                        copy_to_user((struct m68k_serial *) arg,
                                    info, sizeof(struct m68k_serial));
                        return 0;
                        
                default:
                        return -ENOIOCTLCMD;
                }
        return 0;
}

static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;

        if (tty->termios->c_cflag == old_termios->c_cflag)
                return;

        change_speed(info);

        if ((old_termios->c_cflag & CRTSCTS) &&
            !(tty->termios->c_cflag & CRTSCTS)) {
                tty->hw_stopped = 0;
                rs_start(tty);
        }
        
}

/*
 * ------------------------------------------------------------
 * rs_close()
 * 
 * This routine is called when the serial port gets closed.  First, we
 * wait for the last remaining data to be sent.  Then, we unlink its
 * S structure from the interrupt chain if necessary, and we free
 * that IRQ if nothing is left in the chain.
 * ------------------------------------------------------------
 */
static void rs_close(struct tty_struct *tty, struct file * filp)
{
        struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
        m68328_uart *uart = &uart_addr[info->line];
        unsigned long flags;

        if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
                return;
        
        save_flags(flags); cli();
        
        if (tty_hung_up_p(filp)) {
                restore_flags(flags);
                return;
        }
        
        if ((tty->count == 1) && (info->count != 1)) {
                /*
                 * Uh, oh.  tty->count is 1, which means that the tty
                 * structure will be freed.  Info->count should always
                 * be one in these conditions.  If it's greater than
                 * one, we've got real problems, since it means the
                 * serial port won't be shutdown.
                 */
                printk("rs_close: bad serial port count; tty->count is 1, "
                       "info->count is %d\n", info->count);
                info->count = 1;
        }
        if (--info->count < 0) {
                printk("rs_close: bad serial port count for ttyS%d: %d\n",
                       info->line, info->count);
                info->count = 0;
        }
        if (info->count) {
                restore_flags(flags);
                return;
        }
        info->flags |= S_CLOSING;
        /*
         * Now we wait for the transmit buffer to clear; and we notify 
         * the line discipline to only process XON/XOFF characters.
         */
        tty->closing = 1;
        if (info->closing_wait != S_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, info->closing_wait);
        /*
         * At this point we stop accepting input.  To do this, we
         * disable the receive line status interrupts, and tell the
         * interrupt driver to stop checking the data ready bit in the
         * line status register.
         */

        uart->ustcnt &= ~USTCNT_RXEN;
        uart->ustcnt &= ~(USTCNT_RXEN | USTCNT_RX_INTR_MASK);

        shutdown(info);
        if (tty->driver->flush_buffer)
                tty->driver->flush_buffer(tty);
                
        tty_ldisc_flush(tty);
        tty->closing = 0;
        info->event = 0;
        info->tty = 0;
#warning "This is not and has never been valid so fix it"       
#if 0
        if (tty->ldisc.num != ldiscs[N_TTY].num) {
                if (tty->ldisc.close)
                        (tty->ldisc.close)(tty);
                tty->ldisc = ldiscs[N_TTY];
                tty->termios->c_line = N_TTY;
                if (tty->ldisc.open)
                        (tty->ldisc.open)(tty);
        }
#endif  
        if (info->blocked_open) {
                if (info->close_delay) {
                        msleep_interruptible(jiffies_to_msecs(info->close_delay));
                }
                wake_up_interruptible(&info->open_wait);
        }
        info->flags &= ~(S_NORMAL_ACTIVE|S_CLOSING);
        wake_up_interruptible(&info->close_wait);
        restore_flags(flags);
}

/*
 * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
 */
void rs_hangup(struct tty_struct *tty)
{
        struct m68k_serial * info = (struct m68k_serial *)tty->driver_data;
        
        if (serial_paranoia_check(info, tty->name, "rs_hangup"))
                return;
        
        rs_flush_buffer(tty);
        shutdown(info);
        info->event = 0;
        info->count = 0;
        info->flags &= ~S_NORMAL_ACTIVE;
        info->tty = 0;
        wake_up_interruptible(&info->open_wait);
}

/*
 * ------------------------------------------------------------
 * rs_open() and friends
 * ------------------------------------------------------------
 */
static int block_til_ready(struct tty_struct *tty, struct file * filp,
                           struct m68k_serial *info)
{
        DECLARE_WAITQUEUE(wait, current);
        int             retval;
        int             do_clocal = 0;

        /*
         * If the device is in the middle of being closed, then block
         * until it's done, and then try again.
         */
        if (info->flags & S_CLOSING) {
                interruptible_sleep_on(&info->close_wait);
#ifdef SERIAL_DO_RESTART
                if (info->flags & S_HUP_NOTIFY)
                        return -EAGAIN;
                else
                        return -ERESTARTSYS;
#else
                return -EAGAIN;
#endif
        }
        
        /*
         * If non-blocking mode is set, or the port is not enabled,
         * then make the check up front and then exit.
         */
        if ((filp->f_flags & O_NONBLOCK) ||
            (tty->flags & (1 << TTY_IO_ERROR))) {
                info->flags |= S_NORMAL_ACTIVE;
                return 0;
        }

        if (tty->termios->c_cflag & CLOCAL)
                do_clocal = 1;

        /*
         * Block waiting for the carrier detect and the line to become
         * free (i.e., not in use by the callout).  While we are in
         * this loop, info->count is dropped by one, so that
         * rs_close() knows when to free things.  We restore it upon
         * exit, either normal or abnormal.
         */
        retval = 0;
        add_wait_queue(&info->open_wait, &wait);

        info->count--;
        info->blocked_open++;
        while (1) {
                cli();
                m68k_rtsdtr(info, 1);
                sti();
                current->state = TASK_INTERRUPTIBLE;
                if (tty_hung_up_p(filp) ||
                    !(info->flags & S_INITIALIZED)) {
#ifdef SERIAL_DO_RESTART
                        if (info->flags & S_HUP_NOTIFY)
                                retval = -EAGAIN;
                        else
                                retval = -ERESTARTSYS;  
#else
                        retval = -EAGAIN;
#endif
                        break;
                }
                if (!(info->flags & S_CLOSING) && do_clocal)
                        break;
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
                }
                schedule();
        }
        current->state = TASK_RUNNING;
        remove_wait_queue(&info->open_wait, &wait);
        if (!tty_hung_up_p(filp))
                info->count++;
        info->blocked_open--;

        if (retval)
                return retval;
        info->flags |= S_NORMAL_ACTIVE;
        return 0;
}       

/*
 * This routine is called whenever a serial port is opened.  It
 * enables interrupts for a serial port, linking in its S structure into
 * the IRQ chain.   It also performs the serial-specific
 * initialization for the tty structure.
 */
int rs_open(struct tty_struct *tty, struct file * filp)
{
        struct m68k_serial      *info;
        int                     retval, line;

        line = tty->index;
        
        if (line >= NR_PORTS || line < 0) /* we have exactly one */
                return -ENODEV;

        info = &m68k_soft[line];

        if (serial_paranoia_check(info, tty->name, "rs_open"))
                return -ENODEV;

        info->count++;
        tty->driver_data = info;
        info->tty = tty;

        /*
         * Start up serial port
         */
        retval = startup(info);
        if (retval)
                return retval;

        return block_til_ready(tty, filp, info);
}

/* Finally, routines used to initialize the serial driver. */

static void show_serial_version(void)
{
        printk("MC68328 serial driver version 1.00\n");
}

#ifdef CONFIG_PM_LEGACY
/* Serial Power management
 *  The console (currently fixed at line 0) is a special case for power
 *  management because the kernel is so chatty. The console will be 
 *  explicitly disabled my our power manager as the last minute, so we won't
 *  mess with it here.
 */
static struct pm_dev *serial_pm[NR_PORTS];

static int serial_pm_callback(struct pm_dev *dev, pm_request_t request, void *data)
{
        struct m68k_serial *info = (struct m68k_serial *)dev->data;

        if(info == NULL)
                return -1;

        /* special case for line 0 - pm restores it */
        if(info->line == 0)
                return 0; 

        switch (request) {
        case PM_SUSPEND:
                shutdown(info);
                break;

        case PM_RESUME:
                startup(info);
                break;
        }
        return 0;
}

void shutdown_console(void)
{
        struct m68k_serial *info = &m68k_soft[0];

        /* HACK: wait a bit for any pending printk's to be dumped */
        {
                int i = 10000;
                while(i--);
        }

        shutdown(info);
}

void startup_console(void)
{
        struct m68k_serial *info = &m68k_soft[0];
        startup(info);
}
#endif /* CONFIG_PM_LEGACY */


static struct tty_operations rs_ops = {
        .open = rs_open,
        .close = rs_close,
        .write = rs_write,
        .flush_chars = rs_flush_chars,
        .write_room = rs_write_room,
        .chars_in_buffer = rs_chars_in_buffer,
        .flush_buffer = rs_flush_buffer,
        .ioctl = rs_ioctl,
        .throttle = rs_throttle,
        .unthrottle = rs_unthrottle,
        .set_termios = rs_set_termios,
        .stop = rs_stop,
        .start = rs_start,
        .hangup = rs_hangup,
        .set_ldisc = rs_set_ldisc,
};

/* rs_init inits the driver */
static int __init
rs68328_init(void)
{
        int flags, i;
        struct m68k_serial *info;

        serial_driver = alloc_tty_driver(NR_PORTS);
        if (!serial_driver)
                return -ENOMEM;

        show_serial_version();

        /* Initialize the tty_driver structure */
        /* SPARC: Not all of this is exactly right for us. */
        
        serial_driver->name = "ttyS";
        serial_driver->major = TTY_MAJOR;
        serial_driver->minor_start = 64;
        serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
        serial_driver->subtype = SERIAL_TYPE_NORMAL;
        serial_driver->init_termios = tty_std_termios;
        serial_driver->init_termios.c_cflag = 
                        m68328_console_cbaud | CS8 | CREAD | HUPCL | CLOCAL;
        serial_driver->flags = TTY_DRIVER_REAL_RAW;
        tty_set_operations(serial_driver, &rs_ops);

        if (tty_register_driver(serial_driver)) {
                put_tty_driver(serial_driver);
                printk(KERN_ERR "Couldn't register serial driver\n");
                return -ENOMEM;
        }

        save_flags(flags); cli();

        for(i=0;i<NR_PORTS;i++) {

            info = &m68k_soft[i];
            info->magic = SERIAL_MAGIC;
            info->port = (int) &uart_addr[i];
            info->tty = 0;
            info->irq = uart_irqs[i];
            info->custom_divisor = 16;
            info->close_delay = 50;
            info->closing_wait = 3000;
            info->x_char = 0;
            info->event = 0;
            info->count = 0;
            info->blocked_open = 0;
            INIT_WORK(&info->tqueue, do_softint, info);
            INIT_WORK(&info->tqueue_hangup, do_serial_hangup, info);
            init_waitqueue_head(&info->open_wait);
            init_waitqueue_head(&info->close_wait);
            info->line = i;
            info->is_cons = 1; /* Means shortcuts work */
            
            printk("%s%d at 0x%08x (irq = %d)", serial_driver->name, info->line, 
                   info->port, info->irq);
            printk(" is a builtin MC68328 UART\n");
            
            IRQ_ports[info->irq] = info;        /* waste of space */

#ifdef CONFIG_M68VZ328
                if (i > 0 )
                        PJSEL &= 0xCF;  /* PSW enable second port output */
#endif

            if (request_irq(uart_irqs[i],
                            rs_interrupt,
                            IRQ_FLG_STD,
                            "M68328_UART", NULL))
                panic("Unable to attach 68328 serial interrupt\n");
#ifdef CONFIG_PM_LEGACY
            serial_pm[i] = pm_register(PM_SYS_DEV, PM_SYS_COM, serial_pm_callback);
            if (serial_pm[i])
                    serial_pm[i]->data = info;
#endif
        }
        restore_flags(flags);
        return 0;
}

module_init(rs68328_init);



static void m68328_set_baud(void)
{
        unsigned short ustcnt;
        int     i;

        ustcnt = USTCNT;
        USTCNT = ustcnt & ~USTCNT_TXEN;

again:
        for (i = 0; i < sizeof(baud_table) / sizeof(baud_table[0]); i++)
                if (baud_table[i] == m68328_console_baud)
                        break;
        if (i >= sizeof(baud_table) / sizeof(baud_table[0])) {
                m68328_console_baud = 9600;
                goto again;
        }

        UBAUD = PUT_FIELD(UBAUD_DIVIDE,    hw_baud_table[i].divisor) | 
                PUT_FIELD(UBAUD_PRESCALER, hw_baud_table[i].prescale);
        ustcnt &= ~(USTCNT_PARITYEN | USTCNT_ODD_EVEN | USTCNT_STOP | USTCNT_8_7);
        ustcnt |= USTCNT_8_7;
        ustcnt |= USTCNT_TXEN;
        USTCNT = ustcnt;
        m68328_console_initted = 1;
        return;
}


int m68328_console_setup(struct console *cp, char *arg)
{
        int             i, n = CONSOLE_BAUD_RATE;

        if (!cp)
                return(-1);

        if (arg)
                n = simple_strtoul(arg,NULL,0);

        for (i = 0; i < BAUD_TABLE_SIZE; i++)
                if (baud_table[i] == n)
                        break;
        if (i < BAUD_TABLE_SIZE) {
                m68328_console_baud = n;
                m68328_console_cbaud = 0;
                if (i > 15) {
                        m68328_console_cbaud |= CBAUDEX;
                        i -= 15;
                }
                m68328_console_cbaud |= i;
        }

        m68328_set_baud(); /* make sure baud rate changes */
        return(0);
}


static struct tty_driver *m68328_console_device(struct console *c, int *index)
{
        *index = c->index;
        return serial_driver;
}


void m68328_console_write (struct console *co, const char *str,
                           unsigned int count)
{
        if (!m68328_console_initted)
                m68328_set_baud();
    while (count--) {
        if (*str == '\n')
           rs_put_char('\r');
        rs_put_char( *str++ );
    }
}


static struct console m68328_driver = {
        .name           = "ttyS",
        .write          = m68328_console_write,
        .device         = m68328_console_device,
        .setup          = m68328_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
};


static int __init m68328_console_init(void)
{
        register_console(&m68328_driver);
        return 0;
}

console_initcall(m68328_console_init);