Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/* -*- linux-c -*- ------------------------------------------------------- *

 *

 *   Copyright (C) 1991, 1992 Linus Torvalds

 *   Copyright 2007 rPath, Inc. - All Rights Reserved

 *

 *   This file is part of the Linux kernel, and is made available under

 *   the terms of the GNU General Public License version 2.

 *

 * ----------------------------------------------------------------------- */

/*

 * arch/i386/boot/tty.c

 *

 * Very simple screen I/O

 * XXX: Probably should add very simple serial I/O?

 */

#include "boot.h"

/*

 * These functions are in .inittext so they can be used to signal

 * error during initialization.

 */

void __attribute__((section(".inittext"))) putchar(int ch)

{

        unsigned char c = ch;

        if (c == '\n')

                putchar('\r');  /* \n -> \r\n */

        /* int $0x10 is known to have bugs involving touching registers

           it shouldn't.  Be extra conservative... */

        asm volatile("pushal; pushw %%ds; int $0x10; popw %%ds; popal"

                     : : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch));

}

void __attribute__((section(".inittext"))) puts(const char *str)

{

        int n = 0;

        while (*str) {

                putchar(*str++);

                n++;

        }

}

/*

 * Read the CMOS clock through the BIOS, and return the

 * seconds in BCD.

 */

static u8 gettime(void)

{

        u16 ax = 0x0200;

        u16 cx, dx;

        asm volatile("int $0x1a"

                     : "+a" (ax), "=c" (cx), "=d" (dx)

                     : : "ebx", "esi", "edi");

        return dx >> 8;

}

/*

 * Read from the keyboard

 */

int getchar(void)

{

        u16 ax = 0;

        asm volatile("int $0x16" : "+a" (ax));

        return ax & 0xff;

}

static int kbd_pending(void)

{

        u8 pending;

        asm volatile("int $0x16; setnz %0"

                     : "=rm" (pending)

                     : "a" (0x0100));

        return pending;

}

void kbd_flush(void)

{

        for (;;) {

                if (!kbd_pending())

                        break;

                getchar();

        }

}

int getchar_timeout(void)

{

        int cnt = 30;

        int t0, t1;

        t0 = gettime();

        while (cnt) {

                if (kbd_pending())

                        return getchar();

                t1 = gettime();

                if (t0 != t1) {

                        cnt--;

                        t0 = t1;

                }

        }

        return 0;                /* Timeout! */

}