arch/x86/boot/video.h

   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
  72 void 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
  82 struct 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
  88 struct 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")))
 100 extern struct card_info video_cards[], video_cards_end[];
 101
 102 int 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
 109 extern int adapter;
 110 extern u16 video_segment;
 111 extern int force_x, force_y;    /* Don't query the BIOS for cols/rows */
 112 extern int do_restore;          /* Restore screen contents */
 113 extern 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 */
 130 static inline u8 in_idx(u16 port, u8 index)
 131 {
 132         outb(index, port);
 133         return inb(port+1);
 134 }
 135
 136 static 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 */
 142 static 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 */
 149 u16 vga_crtc(void);             /* video-vga.c */
 150
 151 #endif /* BOOT_VIDEO_H */