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  *
   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  * arch/i386/boot/video-vga.c
  13  *
  14  * Common all-VGA modes
  15  */
  16
  17 #include "boot.h"
  18 #include "video.h"
  19
  20 static struct mode_info vga_modes[] = {
  21         { VIDEO_80x25,  80, 25, 0 },
  22         { VIDEO_8POINT, 80, 50, 0 },
  23         { VIDEO_80x43,  80, 43, 0 },
  24         { VIDEO_80x28,  80, 28, 0 },
  25         { VIDEO_80x30,  80, 30, 0 },
  26         { VIDEO_80x34,  80, 34, 0 },
  27         { VIDEO_80x60,  80, 60, 0 },
  28 };
  29
  30 static struct mode_info ega_modes[] = {
  31         { VIDEO_80x25,  80, 25, 0 },
  32         { VIDEO_8POINT, 80, 43, 0 },
  33 };
  34
  35 static struct mode_info cga_modes[] = {
  36         { VIDEO_80x25,  80, 25, 0 },
  37 };
  38
  39 __videocard video_vga;
  40
  41 /* Set basic 80x25 mode */
  42 static u8 vga_set_basic_mode(void)
  43 {
  44         u16 ax;
  45         u8 rows;
  46         u8 mode;
  47
  48 #ifdef CONFIG_VIDEO_400_HACK
  49         if (adapter >= ADAPTER_VGA) {
  50                 asm volatile(INT10
  51                              : : "a" (0x1202), "b" (0x0030)
  52                              : "ecx", "edx", "esi", "edi");
  53         }
  54 #endif
  55
  56         ax = 0x0f00;
  57         asm volatile(INT10
  58                      : "+a" (ax)
  59                      : : "ebx", "ecx", "edx", "esi", "edi");
  60
  61         mode = (u8)ax;
  62
  63         set_fs(0);
  64         rows = rdfs8(0x484);    /* rows minus one */
  65
  66 #ifndef CONFIG_VIDEO_400_HACK
  67         if ((ax == 0x5003 || ax == 0x5007) &&
  68             (rows == 0 || rows == 24))
  69                 return mode;
  70 #endif
  71
  72         if (mode != 3 && mode != 7)
  73                 mode = 3;
  74
  75         /* Set the mode */
  76         ax = mode;
  77         asm volatile(INT10
  78                      : "+a" (ax)
  79                      : : "ebx", "ecx", "edx", "esi", "edi");
  80         do_restore = 1;
  81         return mode;
  82 }
  83
  84 static void vga_set_8font(void)
  85 {
  86         /* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */
  87
  88         /* Set 8x8 font */
  89         asm volatile(INT10 : : "a" (0x1112), "b" (0));
  90
  91         /* Use alternate print screen */
  92         asm volatile(INT10 : : "a" (0x1200), "b" (0x20));
  93
  94         /* Turn off cursor emulation */
  95         asm volatile(INT10 : : "a" (0x1201), "b" (0x34));
  96
  97         /* Cursor is scan lines 6-7 */
  98         asm volatile(INT10 : : "a" (0x0100), "c" (0x0607));
  99 }
 100
 101 static void vga_set_14font(void)
 102 {
 103         /* Set 9x14 font - 80x28 on VGA */
 104
 105         /* Set 9x14 font */
 106         asm volatile(INT10 : : "a" (0x1111), "b" (0));
 107
 108         /* Turn off cursor emulation */
 109         asm volatile(INT10 : : "a" (0x1201), "b" (0x34));
 110
 111         /* Cursor is scan lines 11-12 */
 112         asm volatile(INT10 : : "a" (0x0100), "c" (0x0b0c));
 113 }
 114
 115 static void vga_set_80x43(void)
 116 {
 117         /* Set 80x43 mode on VGA (not EGA) */
 118
 119         /* Set 350 scans */
 120         asm volatile(INT10 : : "a" (0x1201), "b" (0x30));
 121
 122         /* Reset video mode */
 123         asm volatile(INT10 : : "a" (0x0003));
 124
 125         vga_set_8font();
 126 }
 127
 128 /* I/O address of the VGA CRTC */
 129 u16 vga_crtc(void)
 130 {
 131         return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
 132 }
 133
 134 static void vga_set_480_scanlines(int end)
 135 {
 136         u16 crtc;
 137         u8  csel;
 138
 139         crtc = vga_crtc();
 140
 141         out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
 142         out_idx(0x0b, crtc, 0x06); /* Vertical total */
 143         out_idx(0x3e, crtc, 0x07); /* Vertical overflow */
 144         out_idx(0xea, crtc, 0x10); /* Vertical sync start */
 145         out_idx(end, crtc, 0x12); /* Vertical display end */
 146         out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
 147         out_idx(0x04, crtc, 0x16); /* Vertical blank end */
 148         csel = inb(0x3cc);
 149         csel &= 0x0d;
 150         csel |= 0xe2;
 151         outb(csel, 0x3cc);
 152 }
 153
 154 static void vga_set_80x30(void)
 155 {
 156         vga_set_480_scanlines(0xdf);
 157 }
 158
 159 static void vga_set_80x34(void)
 160 {
 161         vga_set_14font();
 162         vga_set_480_scanlines(0xdb);
 163 }
 164
 165 static void vga_set_80x60(void)
 166 {
 167         vga_set_8font();
 168         vga_set_480_scanlines(0xdf);
 169 }
 170
 171 static int vga_set_mode(struct mode_info *mode)
 172 {
 173         /* Set the basic mode */
 174         vga_set_basic_mode();
 175
 176         /* Override a possibly broken BIOS */
 177         force_x = mode->x;
 178         force_y = mode->y;
 179
 180         switch (mode->mode) {
 181         case VIDEO_80x25:
 182                 break;
 183         case VIDEO_8POINT:
 184                 vga_set_8font();
 185                 break;
 186         case VIDEO_80x43:
 187                 vga_set_80x43();
 188                 break;
 189         case VIDEO_80x28:
 190                 vga_set_14font();
 191                 break;
 192         case VIDEO_80x30:
 193                 vga_set_80x30();
 194                 break;
 195         case VIDEO_80x34:
 196                 vga_set_80x34();
 197                 break;
 198         case VIDEO_80x60:
 199                 vga_set_80x60();
 200                 break;
 201         }
 202
 203         return 0;
 204 }
 205
 206 /*
 207  * Note: this probe includes basic information required by all
 208  * systems.  It should be executed first, by making sure
 209  * video-vga.c is listed first in the Makefile.
 210  */
 211 static int vga_probe(void)
 212 {
 213         static const char *card_name[] = {
 214                 "CGA/MDA/HGC", "EGA", "VGA"
 215         };
 216         static struct mode_info *mode_lists[] = {
 217                 cga_modes,
 218                 ega_modes,
 219                 vga_modes,
 220         };
 221         static int mode_count[] = {
 222                 sizeof(cga_modes)/sizeof(struct mode_info),
 223                 sizeof(ega_modes)/sizeof(struct mode_info),
 224                 sizeof(vga_modes)/sizeof(struct mode_info),
 225         };
 226         u8 vga_flag;
 227
 228         asm(INT10
 229             : "=b" (boot_params.screen_info.orig_video_ega_bx)
 230             : "a" (0x1200), "b" (0x10) /* Check EGA/VGA */
 231             : "ecx", "edx", "esi", "edi");
 232
 233         /* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
 234         if ((u8)boot_params.screen_info.orig_video_ega_bx != 0x10) {
 235                 /* EGA/VGA */
 236                 asm(INT10
 237                     : "=a" (vga_flag)
 238                     : "a" (0x1a00)
 239                     : "ebx", "ecx", "edx", "esi", "edi");
 240
 241                 if (vga_flag == 0x1a) {
 242                         adapter = ADAPTER_VGA;
 243                         boot_params.screen_info.orig_video_isVGA = 1;
 244                 } else {
 245                         adapter = ADAPTER_EGA;
 246                 }
 247         } else {
 248                 adapter = ADAPTER_CGA;
 249         }
 250
 251         video_vga.modes = mode_lists[adapter];
 252         video_vga.card_name = card_name[adapter];
 253         return mode_count[adapter];
 254 }
 255
 256 __videocard video_vga =
 257 {
 258         .card_name      = "VGA",
 259         .probe          = vga_probe,
 260         .set_mode       = vga_set_mode,
 261 };