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