[deliverable/linux.git] / arch / x86 / boot / video-bios.c

/* -*- 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.
 *
 * ----------------------------------------------------------------------- */

/*
 * Standard video BIOS modes
 *
 * We have two options for this; silent and scanned.
 */

#include "boot.h"
#include "video.h"

static __videocard video_bios;

/* Set a conventional BIOS mode */
static int set_bios_mode(u8 mode);

static int bios_set_mode(struct mode_info *mi)
{
	return set_bios_mode(mi->mode - VIDEO_FIRST_BIOS);
}

static int set_bios_mode(u8 mode)
{
	u16 ax;
	u8 new_mode;

	ax = mode;		/* AH=0x00 Set Video Mode */
	asm volatile(INT10
		     : "+a" (ax)
		     : : "ebx", "ecx", "edx", "esi", "edi");

	ax = 0x0f00;		/* Get Current Video Mode */
	asm volatile(INT10
		     : "+a" (ax)
		     : : "ebx", "ecx", "edx", "esi", "edi");

	do_restore = 1;		/* Assume video contents were lost */
	new_mode = ax & 0x7f;	/* Not all BIOSes are clean with the top bit */

	if (new_mode == mode)
		return 0;	/* Mode change OK */

#ifndef _WAKEUP
	if (new_mode != boot_params.screen_info.orig_video_mode) {
		/* Mode setting failed, but we didn't end up where we
		   started.  That's bad.  Try to revert to the original
		   video mode. */
		ax = boot_params.screen_info.orig_video_mode;
		asm volatile(INT10
			     : "+a" (ax)
			     : : "ebx", "ecx", "edx", "esi", "edi");
	}
#endif
	return -1;
}

static int bios_probe(void)
{
	u8 mode;
#ifdef _WAKEUP
	u8 saved_mode = 0x03;
#else
	u8 saved_mode = boot_params.screen_info.orig_video_mode;
#endif
	u16 crtc;
	struct mode_info *mi;
	int nmodes = 0;

	if (adapter != ADAPTER_EGA && adapter != ADAPTER_VGA)
		return 0;

	set_fs(0);
	crtc = vga_crtc();

	video_bios.modes = GET_HEAP(struct mode_info, 0);

	for (mode = 0x14; mode <= 0x7f; mode++) {
		if (!heap_free(sizeof(struct mode_info)))
			break;

		if (mode_defined(VIDEO_FIRST_BIOS+mode))
			continue;

		if (set_bios_mode(mode))
			continue;

		/* Try to verify that it's a text mode. */

		/* Attribute Controller: make graphics controller disabled */
		if (in_idx(0x3c0, 0x10) & 0x01)
			continue;

		/* Graphics Controller: verify Alpha addressing enabled */
		if (in_idx(0x3ce, 0x06) & 0x01)
			continue;

		/* CRTC cursor location low should be zero(?) */
		if (in_idx(crtc, 0x0f))
			continue;

		mi = GET_HEAP(struct mode_info, 1);
		mi->mode = VIDEO_FIRST_BIOS+mode;
		mi->depth = 0;	/* text */
		mi->x = rdfs16(0x44a);
		mi->y = rdfs8(0x484)+1;
		nmodes++;
	}

	set_bios_mode(saved_mode);

	return nmodes;
}

static __videocard video_bios =
{
	.card_name	= "BIOS",
	.probe		= bios_probe,
	.set_mode	= bios_set_mode,
	.unsafe		= 1,
	.xmode_first	= VIDEO_FIRST_BIOS,
	.xmode_n	= 0x80,
};
Commit	Line	Data
5e8ddcbe PA	1	/* -- linux-c -- ------------------------------------------------------- *
	2	*
	3	* Copyright (C) 1991, 1992 Linus Torvalds
	4	* Copyright 2007 rPath, Inc. - All Rights Reserved
	5	*
	6	* This file is part of the Linux kernel, and is made available under
	7	* the terms of the GNU General Public License version 2.
	8	*
	9	* ----------------------------------------------------------------------- */
	10
	11	/*
5e8ddcbe PA	12	* Standard video BIOS modes
	13	*
	14	* We have two options for this; silent and scanned.
	15	*/
	16
	17	#include "boot.h"
	18	#include "video.h"
	19
8bcad30f	20	static __videocard video_bios;
5e8ddcbe PA	21
	22	/* Set a conventional BIOS mode */
	23	static int set_bios_mode(u8 mode);
	24
	25	static int bios_set_mode(struct mode_info *mi)
	26	{
	27	return set_bios_mode(mi->mode - VIDEO_FIRST_BIOS);
	28	}
	29
	30	static int set_bios_mode(u8 mode)
	31	{
	32	u16 ax;
	33	u8 new_mode;
	34
	35	ax = mode; /* AH=0x00 Set Video Mode */
	36	asm volatile(INT10
	37	: "+a" (ax)
	38	: : "ebx", "ecx", "edx", "esi", "edi");
	39
	40	ax = 0x0f00; /* Get Current Video Mode */
	41	asm volatile(INT10
	42	: "+a" (ax)
	43	: : "ebx", "ecx", "edx", "esi", "edi");
	44
8218d029	45	do_restore = 1; /* Assume video contents were lost */
5e8ddcbe PA	46	new_mode = ax & 0x7f; /* Not all BIOSes are clean with the top bit */
	47
	48	if (new_mode == mode)
	49	return 0; /* Mode change OK */
	50
e44b7b75	51	#ifndef _WAKEUP
5e8ddcbe PA	52	if (new_mode != boot_params.screen_info.orig_video_mode) {
	53	/* Mode setting failed, but we didn't end up where we
	54	started. That's bad. Try to revert to the original
	55	video mode. */
	56	ax = boot_params.screen_info.orig_video_mode;
	57	asm volatile(INT10
	58	: "+a" (ax)
	59	: : "ebx", "ecx", "edx", "esi", "edi");
	60	}
e44b7b75	61	#endif
5e8ddcbe PA	62	return -1;
	63	}
	64
	65	static int bios_probe(void)
	66	{
	67	u8 mode;
e44b7b75 PM	68	#ifdef _WAKEUP
	69	u8 saved_mode = 0x03;
	70	#else
5e8ddcbe	71	u8 saved_mode = boot_params.screen_info.orig_video_mode;
e44b7b75	72	#endif
5e8ddcbe PA	73	u16 crtc;
	74	struct mode_info *mi;
	75	int nmodes = 0;
	76
	77	if (adapter != ADAPTER_EGA && adapter != ADAPTER_VGA)
	78	return 0;
	79
	80	set_fs(0);
	81	crtc = vga_crtc();
	82
	83	video_bios.modes = GET_HEAP(struct mode_info, 0);
	84
	85	for (mode = 0x14; mode <= 0x7f; mode++) {
e6e1ace9	86	if (!heap_free(sizeof(struct mode_info)))
5e8ddcbe PA	87	break;
	88
	89	if (mode_defined(VIDEO_FIRST_BIOS+mode))
	90	continue;
	91
	92	if (set_bios_mode(mode))
	93	continue;
	94
	95	/* Try to verify that it's a text mode. */
	96
	97	/* Attribute Controller: make graphics controller disabled */
	98	if (in_idx(0x3c0, 0x10) & 0x01)
	99	continue;
	100
	101	/* Graphics Controller: verify Alpha addressing enabled */
	102	if (in_idx(0x3ce, 0x06) & 0x01)
	103	continue;
	104
	105	/* CRTC cursor location low should be zero(?) */
	106	if (in_idx(crtc, 0x0f))
	107	continue;
	108
	109	mi = GET_HEAP(struct mode_info, 1);
	110	mi->mode = VIDEO_FIRST_BIOS+mode;
1cac5004	111	mi->depth = 0; /* text */
5e8ddcbe PA	112	mi->x = rdfs16(0x44a);
	113	mi->y = rdfs8(0x484)+1;
	114	nmodes++;
	115	}
	116
	117	set_bios_mode(saved_mode);
	118
	119	return nmodes;
	120	}
	121
8bcad30f	122	static __videocard video_bios =
5e8ddcbe	123	{
1cac5004	124	.card_name = "BIOS",
5e8ddcbe PA	125	.probe = bios_probe,
	126	.set_mode = bios_set_mode,
	127	.unsafe = 1,
	128	.xmode_first = VIDEO_FIRST_BIOS,
	129	.xmode_n = 0x80,
	130	};