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/*

 *   FILE: mon960_console.c

 * AUTHOR: kma

 *  DESCR: serial console for TI's 16552 serial controller

 */

#ident "$Id: mon960_console.c,v 1.1 2005-12-20 09:42:38 jcastillo Exp $"

#include <linux/tty.h>

#include <linux/tty_driver.h>

#include <linux/major.h>

#include <linux/interrupt.h>

#include <asm/system.h>

#include <asm/delay.h>

#define SER16552_LSR    ((volatile unsigned char*)0xe0000014)   /* line status */

#define SER16552_THR    ((volatile unsigned char*)0xe0000000)   /* send fifo */

#define SER16552_RBR    ((volatile unsigned char*)0xe0000000)   /* rcv fifo */

#define SER16552_IER    ((volatile unsigned char*)0xe0000004)   /* int enable */

#define LSR_READY               1

#define LSR_SEND_READY          0x20

#define LSR_RECEIVE_READY       0x1

#define LSR_BREAK               (1 << 4)

#define IER_RCV_ENABLE  1

#define IER_SEND_ENABLE 2

static int console_refcount;

static struct tty_struct *console_table[1];

static struct termios   *console_termios[1];

static struct termios   *console_termios_locked[1];

static struct tty_driver console_driver;

/*

 * The interrupt for the 16552; should only happen for reads

 */

void do_16552_intr(void)

{

        unsigned char           buf[16];

        int                     ii;

        struct tty_struct       *tty = console_table[0];

        unsigned long           lsr;

        /* Drain the fifo into the tty */

        for (ii=0; (lsr = *SER16552_LSR) & LSR_RECEIVE_READY; ii++) {

                /* If there was a break, enter the debugger */

#ifdef CONFIG_MON960

                char    garbage;

                if (lsr & LSR_BREAK) {

                        extern void system_break(void);

                        system_break();

                        garbage = *SER16552_RBR;

                        ii--;

                }

                else

#endif

                        buf[ii] = *SER16552_RBR;

        }

        if (ii)

                tty->ldisc.receive_buf(tty, buf, 0, ii);

}

#if 0

static void do_16552_bh(void)

{

        printk("in 16552 bottom half!\n");

        printk("umm... yeah.\n");

}

#endif

static inline void putc_16552(char c, int blocking)

{

        unsigned long   flags;

        save_flags(flags);

        cli();

top:

        while (!(*SER16552_LSR & LSR_SEND_READY)) {

                udelay(1000);

        }

        *SER16552_THR = c;

        if (c == '\n') {

                c = '\r';

                goto top;

        }

        restore_flags(flags);

}

void console_print_mon960(const char* msg)

{

        long flags;

        char c;

        save_flags(flags);

        cli();

        while (c = *msg++)

                putc_16552(c, 0);

        restore_flags(flags);

}

/*

 * XXX: make this interrupt driven if it's coming from the user

 */

static int con_write(struct tty_struct* tty, int from_user,

                     const unsigned char* buf, int count)

{

        int ii = count;

        while (ii--)

                putc_16552(*buf++, from_user);

        return count;

}

static int con_chars_in_buffer(struct tty_struct *tty)

{

        return 0;                /* we're not buffering */

}

static int con_writeroom(struct tty_struct *tty)

{

        return  8192;           /* could return anything */

}

static void con_putchar(struct tty_struct* tty, unsigned char c)

{

        putc_16552(c, 0);

}

static int con_open(struct tty_struct* tty, struct file* filp)

{

        return 0;

}

/*

 * register our tty driver

 */

void mon960_console_init(void)

{

        memset(&console_driver, 0, sizeof(console_driver));

        console_driver.magic = TTY_DRIVER_MAGIC;

        console_driver.name = "tty";

        console_driver.name_base = 1;

        console_driver.major = TTY_MAJOR;

        console_driver.minor_start = 1;

        console_driver.num = 1;

        console_driver.type = TTY_DRIVER_TYPE_SERIAL;

        console_driver.init_termios = tty_std_termios;

        console_driver.init_termios.c_lflag |= ISIG | ICANON | ECHO

                 | ECHOE | ECHOK ;

        console_driver.init_termios.c_iflag |= ICRNL;

        console_driver.init_termios.c_cflag = CS8 | CREAD | CLOCAL;

        console_driver.flags = TTY_DRIVER_REAL_RAW;

        console_driver.refcount = &console_refcount;

        console_driver.table = console_table;

        console_driver.termios = console_termios;

        console_driver.termios_locked = console_termios_locked;

        console_driver.open = con_open;

        console_driver.write = con_write;

        console_driver.put_char = con_putchar;

        console_driver.write_room = con_writeroom;

        console_driver.chars_in_buffer = con_chars_in_buffer;

        if (tty_register_driver(&console_driver)) {

                printk("Couldn't register console driver\n");

        }

        /*

         * Enable receive interrupts

         */

        *SER16552_IER = IER_RCV_ENABLE;

}