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 rows;
  46         u8 mode;
  47
  48         initregs(&ireg);
  49
  50         ax = 0x0f00;
  51         intcall(0x10, &ireg, &oreg);
  52         mode = oreg.al;
  53
  54         set_fs(0);
  55         rows = rdfs8(0x484);    /* rows minus one */
  56
  57         if ((oreg.ax == 0x5003 || oreg.ax == 0x5007) &&
  58             (rows == 0 || rows == 24))
  59                 return mode;
  60
  61         if (mode != 3 && mode != 7)
  62                 mode = 3;
  63
  64         /* Set the mode */
  65         ireg.ax = mode;         /* AH=0: set mode */
  66         intcall(0x10, &ireg, NULL);
  67         do_restore = 1;
  68         return mode;
  69 }
  70
  71 static void vga_set_8font(void)
  72 {
  73         /* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */
  74         struct biosregs ireg;
  75
  76         initregs(&ireg);
  77
  78         /* Set 8x8 font */
  79         ireg.ax = 0x1112;
  80         /* ireg.bl = 0; */
  81         intcall(0x10, &ireg, NULL);
  82
  83         /* Use alternate print screen */
  84         ireg.ax = 0x1200;
  85         ireg.bl = 0x20;
  86         intcall(0x10, &ireg, NULL);
  87
  88         /* Turn off cursor emulation */
  89         ireg.ax = 0x1201;
  90         ireg.bl = 0x34;
  91         intcall(0x10, &ireg, NULL);
  92
  93         /* Cursor is scan lines 6-7 */
  94         ireg.ax = 0x0100;
  95         ireg.cx = 0x0607;
  96         intcall(0x10, &ireg, NULL);
  97 }
  98
  99 static void vga_set_14font(void)
 100 {
 101         /* Set 9x14 font - 80x28 on VGA */
 102         struct biosregs ireg;
 103
 104         initregs(&ireg);
 105
 106         /* Set 9x14 font */
 107         ireg.ax = 0x1111;
 108         /* ireg.bl = 0; */
 109         intcall(0x10, &ireg, NULL);
 110
 111         /* Turn off cursor emulation */
 112         ireg.ax = 0x1201;
 113         ireg.bl = 0x34;
 114         intcall(0x10, &ireg, NULL);
 115
 116         /* Cursor is scan lines 11-12 */
 117         ireg.ax = 0x0100;
 118         ireg.cx = 0x0b0c;
 119         intcall(0x10, &ireg, NULL);
 120 }
 121
 122 static void vga_set_80x43(void)
 123 {
 124         /* Set 80x43 mode on VGA (not EGA) */
 125         struct biosregs ireg;
 126
 127         initregs(&ireg);
 128
 129         /* Set 350 scans */
 130         ireg.ax = 0x1201;
 131         ireg.bl = 0x30;
 132         intcall(0x10, &ireg, NULL);
 133
 134         /* Reset video mode */
 135         ireg.ax = 0x0003;
 136         intcall(0x10, &ireg, NULL);
 137
 138         vga_set_8font();
 139 }
 140
 141 /* I/O address of the VGA CRTC */
 142 u16 vga_crtc(void)
 143 {
 144         return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
 145 }
 146
 147 static void vga_set_480_scanlines(void)
 148 {
 149         u16 crtc;               /* CRTC base address */
 150         u8  csel;               /* CRTC miscellaneous output register */
 151
 152         crtc = vga_crtc();
 153
 154         out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
 155         out_idx(0x0b, crtc, 0x06); /* Vertical total */
 156         out_idx(0x3e, crtc, 0x07); /* Vertical overflow */
 157         out_idx(0xea, crtc, 0x10); /* Vertical sync start */
 158         out_idx(0xdf, crtc, 0x12); /* Vertical display end */
 159         out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
 160         out_idx(0x04, crtc, 0x16); /* Vertical blank end */
 161         csel = inb(0x3cc);
 162         csel &= 0x0d;
 163         csel |= 0xe2;
 164         outb(csel, 0x3c2);
 165 }
 166
 167 static void vga_set_vertical_end(int lines)
 168 {
 169         u16 crtc;               /* CRTC base address */
 170         u8  ovfw;               /* CRTC overflow register */
 171         int end = lines-1;
 172
 173         crtc = vga_crtc();
 174
 175         ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);
 176
 177         out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
 178         out_idx(end,  crtc, 0x12); /* Vertical display end */
 179 }
 180
 181 static void vga_set_80x30(void)
 182 {
 183         vga_set_480_scanlines();
 184         vga_set_vertical_end(30*16);
 185 }
 186
 187 static void vga_set_80x34(void)
 188 {
 189         vga_set_480_scanlines();
 190         vga_set_14font();
 191         vga_set_vertical_end(34*14);
 192 }
 193
 194 static void vga_set_80x60(void)
 195 {
 196         vga_set_480_scanlines();
 197         vga_set_8font();
 198         vga_set_vertical_end(60*8);
 199 }
 200
 201 static int vga_set_mode(struct mode_info *mode)
 202 {
 203         /* Set the basic mode */
 204         vga_set_basic_mode();
 205
 206         /* Override a possibly broken BIOS */
 207         force_x = mode->x;
 208         force_y = mode->y;
 209
 210         switch (mode->mode) {
 211         case VIDEO_80x25:
 212                 break;
 213         case VIDEO_8POINT:
 214                 vga_set_8font();
 215                 break;
 216         case VIDEO_80x43:
 217                 vga_set_80x43();
 218                 break;
 219         case VIDEO_80x28:
 220                 vga_set_14font();
 221                 break;
 222         case VIDEO_80x30:
 223                 vga_set_80x30();
 224                 break;
 225         case VIDEO_80x34:
 226                 vga_set_80x34();
 227                 break;
 228         case VIDEO_80x60:
 229                 vga_set_80x60();
 230                 break;
 231         }
 232
 233         return 0;
 234 }
 235
 236 /*
 237  * Note: this probe includes basic information required by all
 238  * systems.  It should be executed first, by making sure
 239  * video-vga.c is listed first in the Makefile.
 240  */
 241 static int vga_probe(void)
 242 {
 243         static const char *card_name[] = {
 244                 "CGA/MDA/HGC", "EGA", "VGA"
 245         };
 246         static struct mode_info *mode_lists[] = {
 247                 cga_modes,
 248                 ega_modes,
 249                 vga_modes,
 250         };
 251         static int mode_count[] = {
 252                 sizeof(cga_modes)/sizeof(struct mode_info),
 253                 sizeof(ega_modes)/sizeof(struct mode_info),
 254                 sizeof(vga_modes)/sizeof(struct mode_info),
 255         };
 256
 257         struct biosregs ireg, oreg;
 258
 259         initregs(&ireg);
 260
 261         ireg.ax = 0x1200;
 262         ireg.bl = 0x10;         /* Check EGA/VGA */
 263         intcall(0x10, &ireg, &oreg);
 264
 265 #ifndef _WAKEUP
 266         boot_params.screen_info.orig_video_ega_bx = oreg.bx;
 267 #endif
 268
 269         /* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
 270         if (oreg.bl != 0x10) {
 271                 /* EGA/VGA */
 272                 ireg.ax = 0x1a00;
 273                 intcall(0x10, &ireg, &oreg);
 274
 275                 if (oreg.al == 0x1a) {
 276                         adapter = ADAPTER_VGA;
 277 #ifndef _WAKEUP
 278                         boot_params.screen_info.orig_video_isVGA = 1;
 279 #endif
 280                 } else {
 281                         adapter = ADAPTER_EGA;
 282                 }
 283         } else {
 284                 adapter = ADAPTER_CGA;
 285         }
 286
 287         video_vga.modes = mode_lists[adapter];
 288         video_vga.card_name = card_name[adapter];
 289         return mode_count[adapter];
 290 }
 291
 292 static __videocard video_vga = {
 293         .card_name      = "VGA",
 294         .probe          = vga_probe,
 295         .set_mode       = vga_set_mode,
 296 };