linux/arch/x86/boot/video.h
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   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/*
  12 * Header file for the real-mode video probing code
  13 */
  14
  15#ifndef BOOT_VIDEO_H
  16#define BOOT_VIDEO_H
  17
  18#include <linux/types.h>
  19
  20/* Enable autodetection of SVGA adapters and modes. */
  21#undef CONFIG_VIDEO_SVGA
  22
  23/* Enable autodetection of VESA modes */
  24#define CONFIG_VIDEO_VESA
  25
  26/* Retain screen contents when switching modes */
  27#define CONFIG_VIDEO_RETAIN
  28
  29/* Force 400 scan lines for standard modes (hack to fix bad BIOS behaviour */
  30#undef CONFIG_VIDEO_400_HACK
  31
  32/* This code uses an extended set of video mode numbers. These include:
  33 * Aliases for standard modes
  34 *      NORMAL_VGA (-1)
  35 *      EXTENDED_VGA (-2)
  36 *      ASK_VGA (-3)
  37 * Video modes numbered by menu position -- NOT RECOMMENDED because of lack
  38 * of compatibility when extending the table. These are between 0x00 and 0xff.
  39 */
  40#define VIDEO_FIRST_MENU 0x0000
  41
  42/* Standard BIOS video modes (BIOS number + 0x0100) */
  43#define VIDEO_FIRST_BIOS 0x0100
  44
  45/* VESA BIOS video modes (VESA number + 0x0200) */
  46#define VIDEO_FIRST_VESA 0x0200
  47
  48/* Video7 special modes (BIOS number + 0x0900) */
  49#define VIDEO_FIRST_V7 0x0900
  50
  51/* Special video modes */
  52#define VIDEO_FIRST_SPECIAL 0x0f00
  53#define VIDEO_80x25 0x0f00
  54#define VIDEO_8POINT 0x0f01
  55#define VIDEO_80x43 0x0f02
  56#define VIDEO_80x28 0x0f03
  57#define VIDEO_CURRENT_MODE 0x0f04
  58#define VIDEO_80x30 0x0f05
  59#define VIDEO_80x34 0x0f06
  60#define VIDEO_80x60 0x0f07
  61#define VIDEO_GFX_HACK 0x0f08
  62#define VIDEO_LAST_SPECIAL 0x0f09
  63
  64/* Video modes given by resolution */
  65#define VIDEO_FIRST_RESOLUTION 0x1000
  66
  67/* The "recalculate timings" flag */
  68#define VIDEO_RECALC 0x8000
  69
  70/* Define DO_STORE according to CONFIG_VIDEO_RETAIN */
  71#ifdef CONFIG_VIDEO_RETAIN
  72void store_screen(void);
  73#define DO_STORE() store_screen()
  74#else
  75#define DO_STORE() ((void)0)
  76#endif /* CONFIG_VIDEO_RETAIN */
  77
  78/*
  79 * Mode table structures
  80 */
  81
  82struct mode_info {
  83        u16 mode;               /* Mode number (vga= style) */
  84        u16 x, y;               /* Width, height */
  85        u16 depth;              /* Bits per pixel, 0 for text mode */
  86};
  87
  88struct card_info {
  89        const char *card_name;
  90        int (*set_mode)(struct mode_info *mode);
  91        int (*probe)(void);
  92        struct mode_info *modes;
  93        int nmodes;             /* Number of probed modes so far */
  94        int unsafe;             /* Probing is unsafe, only do after "scan" */
  95        u16 xmode_first;        /* Unprobed modes to try to call anyway */
  96        u16 xmode_n;            /* Size of unprobed mode range */
  97};
  98
  99#define __videocard struct card_info __attribute__((section(".videocards")))
 100extern struct card_info video_cards[], video_cards_end[];
 101
 102int mode_defined(u16 mode);     /* video.c */
 103
 104/* Basic video information */
 105#define ADAPTER_CGA     0       /* CGA/MDA/HGC */
 106#define ADAPTER_EGA     1
 107#define ADAPTER_VGA     2
 108
 109extern int adapter;
 110extern u16 video_segment;
 111extern int force_x, force_y;    /* Don't query the BIOS for cols/rows */
 112extern int do_restore;          /* Restore screen contents */
 113extern int graphic_mode;        /* Graphics mode with linear frame buffer */
 114
 115/*
 116 * int $0x10 is notorious for touching registers it shouldn't.
 117 * gcc doesn't like %ebp being clobbered, so define it as a push/pop
 118 * sequence here.
 119 *
 120 * A number of systems, including the original PC can clobber %bp in
 121 * certain circumstances, like when scrolling.  There exists at least
 122 * one Trident video card which could clobber DS under a set of
 123 * circumstances that we are unlikely to encounter (scrolling when
 124 * using an extended graphics mode of more than 800x600 pixels), but
 125 * it's cheap insurance to deal with that here.
 126 */
 127#define INT10 "pushl %%ebp; pushw %%ds; int $0x10; popw %%ds; popl %%ebp"
 128
 129/* Accessing VGA indexed registers */
 130static inline u8 in_idx(u16 port, u8 index)
 131{
 132        outb(index, port);
 133        return inb(port+1);
 134}
 135
 136static inline void out_idx(u8 v, u16 port, u8 index)
 137{
 138        outw(index+(v << 8), port);
 139}
 140
 141/* Writes a value to an indexed port and then reads the port again */
 142static inline u8 tst_idx(u8 v, u16 port, u8 index)
 143{
 144        out_idx(port, index, v);
 145        return in_idx(port, index);
 146}
 147
 148/* Get the I/O port of the VGA CRTC */
 149u16 vga_crtc(void);             /* video-vga.c */
 150
 151#endif /* BOOT_VIDEO_H */
 152