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/*

 * Copyright (C) 2001-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <arch/ega.h>

#include <putchar.h>

#include <mm/page.h>

#include <mm/as.h>

#include <arch/mm/page.h>

#include <synch/spinlock.h>

#include <arch/types.h>

#include <arch/asm.h>

#include <memstr.h>

#include <console/chardev.h>

#include <console/console.h>

/*

 * The EGA driver.

 * Simple and short. Function for displaying characters and "scrolling".

 */

SPINLOCK_INITIALIZE(egalock);

static __u32 ega_cursor;

static void ega_putchar(chardev_t *d, const char ch);

chardev_t ega_console;

static chardev_operations_t ega_ops = {

	.write = ega_putchar

};

void ega_move_cursor(void);

void ega_init(void)

{

	__u8 hi, lo;

	page_mapping_insert(AS_KERNEL, PA2KA(VIDEORAM), VIDEORAM, PAGE_NOT_CACHEABLE);

	outb(0x3d4,0xe);

	hi = inb(0x3d5);

	outb(0x3d4,0xf);

	lo = inb(0x3d5);

	ega_cursor = (hi<<8)|lo;

	chardev_initialize("ega_out", &ega_console, &ega_ops);

	stdout = &ega_console;

#ifndef CONFIG_FB

	putchar('\n');

#endif	

}

static void ega_display_char(char ch)

{

	__u8 *vram = (__u8 *) PA2KA(VIDEORAM);

	vram[ega_cursor*2] = ch;

}

/*

 * This function takes care of scrolling.

 */

static void ega_check_cursor(void)

{

	if (ega_cursor < SCREEN)

		return;

	memcpy((void *)PA2KA(VIDEORAM), (void *)(PA2KA(VIDEORAM) + ROW*2), (SCREEN - ROW)*2);

	memsetw(PA2KA(VIDEORAM) + (SCREEN - ROW)*2, ROW, 0x0720);

	ega_cursor = ega_cursor - ROW;

}

void ega_putchar(chardev_t *d, const char ch)

{

	ipl_t ipl;

	ipl = interrupts_disable();

	spinlock_lock(&egalock);

	switch (ch) {

	case '\n':

		ega_cursor = (ega_cursor + ROW) - ega_cursor % ROW;

		break;

	case '\t':

		ega_cursor = (ega_cursor + 8) - ega_cursor % 8;

		break; 

	case '\b':

		if (ega_cursor % ROW)

			ega_cursor--;

		break;

	default:

		ega_display_char(ch);

		ega_cursor++;

		break;

        }

	ega_check_cursor();

	ega_move_cursor();

	spinlock_unlock(&egalock);

	interrupts_restore(ipl);

}

void ega_move_cursor(void)

{

	outb(0x3d4,0xe);

	outb(0x3d5,(ega_cursor>>8)&0xff);

	outb(0x3d4,0xf);

	outb(0x3d5,ega_cursor&0xff);	

}