arch/x86/boot/video-vga.c

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
   5  *   Copyright 2009 Intel Corporation; author H. Peter Anvin
   6  *
   7  *   This file is part of the Linux kernel, and is made available under
   8  *   the terms of the GNU General Public License version 2.
   9  *
  10  * ----------------------------------------------------------------------- */
  11
  12 /*
  13  * Common all-VGA modes
  14  */
  15
  16 #include "boot.h"
  17 #include "video.h"
  18
  19 static struct mode_info vga_modes[] = {
  20         { VIDEO_80x25,  80, 25, 0 },
  21         { VIDEO_8POINT, 80, 50, 0 },
  22         { VIDEO_80x43,  80, 43, 0 },
  23         { VIDEO_80x28,  80, 28, 0 },
  24         { VIDEO_80x30,  80, 30, 0 },
  25         { VIDEO_80x34,  80, 34, 0 },
  26         { VIDEO_80x60,  80, 60, 0 },
  27 };
  28
  29 static struct mode_info ega_modes[] = {
  30         { VIDEO_80x25,  80, 25, 0 },
  31         { VIDEO_8POINT, 80, 43, 0 },
  32 };
  33
  34 static struct mode_info cga_modes[] = {
  35         { VIDEO_80x25,  80, 25, 0 },
  36 };
  37
  38 static __videocard video_vga;
  39
  40 /* Set basic 80x25 mode */
  41 static u8 vga_set_basic_mode(void)
  42 {
  43         struct biosregs ireg, oreg;
  44         u16 ax;
  45         u8 mode;
  46
  47         initregs(&ireg);
  48
  49         /* Query current mode */
  50         ax = 0x0f00;
  51         intcall(0x10, &ireg, &oreg);
  52         mode = oreg.al;
  53
  54         if (mode != 3 && mode != 7)
  55                 mode = 3;
  56
  57         /* Set the mode */
  58         ireg.ax = mode;         /* AH=0: set mode */
  59         intcall(0x10, &ireg, NULL);
  60         do_restore = 1;
  61         return mode;
  62 }
  63
  64 static void vga_set_8font(void)
  65 {
  66         /* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */
  67         struct biosregs ireg;
  68
  69         initregs(&ireg);
  70
  71         /* Set 8x8 font */
  72         ireg.ax = 0x1112;
  73         /* ireg.bl = 0; */
  74         intcall(0x10, &ireg, NULL);
  75
  76         /* Use alternate print screen */
  77         ireg.ax = 0x1200;
  78         ireg.bl = 0x20;
  79         intcall(0x10, &ireg, NULL);
  80
  81         /* Turn off cursor emulation */
  82         ireg.ax = 0x1201;
  83         ireg.bl = 0x34;
  84         intcall(0x10, &ireg, NULL);
  85
  86         /* Cursor is scan lines 6-7 */
  87         ireg.ax = 0x0100;
  88         ireg.cx = 0x0607;
  89         intcall(0x10, &ireg, NULL);
  90 }
  91
  92 static void vga_set_14font(void)
  93 {
  94         /* Set 9x14 font - 80x28 on VGA */
  95         struct biosregs ireg;
  96
  97         initregs(&ireg);
  98
  99         /* Set 9x14 font */
 100         ireg.ax = 0x1111;
 101         /* ireg.bl = 0; */
 102         intcall(0x10, &ireg, NULL);
 103
 104         /* Turn off cursor emulation */
 105         ireg.ax = 0x1201;
 106         ireg.bl = 0x34;
 107         intcall(0x10, &ireg, NULL);
 108
 109         /* Cursor is scan lines 11-12 */
 110         ireg.ax = 0x0100;
 111         ireg.cx = 0x0b0c;
 112         intcall(0x10, &ireg, NULL);
 113 }
 114
 115 static void vga_set_80x43(void)
 116 {
 117         /* Set 80x43 mode on VGA (not EGA) */
 118         struct biosregs ireg;
 119
 120         initregs(&ireg);
 121
 122         /* Set 350 scans */
 123         ireg.ax = 0x1201;
 124         ireg.bl = 0x30;
 125         intcall(0x10, &ireg, NULL);
 126
 127         /* Reset video mode */
 128         ireg.ax = 0x0003;
 129         intcall(0x10, &ireg, NULL);
 130
 131         vga_set_8font();
 132 }
 133
 134 /* I/O address of the VGA CRTC */
 135 u16 vga_crtc(void)
 136 {
 137         return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
 138 }
 139
 140 static void vga_set_480_scanlines(void)
 141 {
 142         u16 crtc;               /* CRTC base address */
 143         u8  csel;               /* CRTC miscellaneous output register */
 144
 145         crtc = vga_crtc();
 146
 147         out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
 148         out_idx(0x0b, crtc, 0x06); /* Vertical total */
 149         out_idx(0x3e, crtc, 0x07); /* Vertical overflow */
 150         out_idx(0xea, crtc, 0x10); /* Vertical sync start */
 151         out_idx(0xdf, crtc, 0x12); /* Vertical display end */
 152         out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
 153         out_idx(0x04, crtc, 0x16); /* Vertical blank end */
 154         csel = inb(0x3cc);
 155         csel &= 0x0d;
 156         csel |= 0xe2;
 157         outb(csel, 0x3c2);
 158 }
 159
 160 static void vga_set_vertical_end(int lines)
 161 {
 162         u16 crtc;               /* CRTC base address */
 163         u8  ovfw;               /* CRTC overflow register */
 164         int end = lines-1;
 165
 166         crtc = vga_crtc();
 167
 168         ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);
 169
 170         out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
 171         out_idx(end,  crtc, 0x12); /* Vertical display end */
 172 }
 173
 174 static void vga_set_80x30(void)
 175 {
 176         vga_set_480_scanlines();
 177         vga_set_vertical_end(30*16);
 178 }
 179
 180 static void vga_set_80x34(void)
 181 {
 182         vga_set_480_scanlines();
 183         vga_set_14font();
 184         vga_set_vertical_end(34*14);
 185 }
 186
 187 static void vga_set_80x60(void)
 188 {
 189         vga_set_480_scanlines();
 190         vga_set_8font();
 191         vga_set_vertical_end(60*8);
 192 }
 193
 194 static int vga_set_mode(struct mode_info *mode)
 195 {
 196         /* Set the basic mode */
 197         vga_set_basic_mode();
 198
 199         /* Override a possibly broken BIOS */
 200         force_x = mode->x;
 201         force_y = mode->y;
 202
 203         switch (mode->mode) {
 204         case VIDEO_80x25:
 205                 break;
 206         case VIDEO_8POINT:
 207                 vga_set_8font();
 208                 break;
 209         case VIDEO_80x43:
 210                 vga_set_80x43();
 211                 break;
 212         case VIDEO_80x28:
 213                 vga_set_14font();
 214                 break;
 215         case VIDEO_80x30:
 216                 vga_set_80x30();
 217                 break;
 218         case VIDEO_80x34:
 219                 vga_set_80x34();
 220                 break;
 221         case VIDEO_80x60:
 222                 vga_set_80x60();
 223                 break;
 224         }
 225
 226         return 0;
 227 }
 228
 229 /*
 230  * Note: this probe includes basic information required by all
 231  * systems.  It should be executed first, by making sure
 232  * video-vga.c is listed first in the Makefile.
 233  */
 234 static int vga_probe(void)
 235 {
 236         static const char *card_name[] = {
 237                 "CGA/MDA/HGC", "EGA", "VGA"
 238         };
 239         static struct mode_info *mode_lists[] = {
 240                 cga_modes,
 241                 ega_modes,
 242                 vga_modes,
 243         };
 244         static int mode_count[] = {
 245                 sizeof(cga_modes)/sizeof(struct mode_info),
 246                 sizeof(ega_modes)/sizeof(struct mode_info),
 247                 sizeof(vga_modes)/sizeof(struct mode_info),
 248         };
 249
 250         struct biosregs ireg, oreg;
 251
 252         initregs(&ireg);
 253
 254         ireg.ax = 0x1200;
 255         ireg.bl = 0x10;         /* Check EGA/VGA */
 256         intcall(0x10, &ireg, &oreg);
 257
 258 #ifndef _WAKEUP
 259         boot_params.screen_info.orig_video_ega_bx = oreg.bx;
 260 #endif
 261
 262         /* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
 263         if (oreg.bl != 0x10) {
 264                 /* EGA/VGA */
 265                 ireg.ax = 0x1a00;
 266                 intcall(0x10, &ireg, &oreg);
 267
 268                 if (oreg.al == 0x1a) {
 269                         adapter = ADAPTER_VGA;
 270 #ifndef _WAKEUP
 271                         boot_params.screen_info.orig_video_isVGA = 1;
 272 #endif
 273                 } else {
 274                         adapter = ADAPTER_EGA;
 275                 }
 276         } else {
 277                 adapter = ADAPTER_CGA;
 278         }
 279
 280         video_vga.modes = mode_lists[adapter];
 281         video_vga.card_name = card_name[adapter];
 282         return mode_count[adapter];
 283 }
 284
 285 static __videocard video_vga = {
 286         .card_name      = "VGA",
 287         .probe          = vga_probe,
 288         .set_mode       = vga_set_mode,
 289 };