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  * Common all-VGA modes
  13  */
  14
  15 #include "boot.h"
  16 #include "video.h"
  17
  18 static struct mode_info vga_modes[] = {
  19         { VIDEO_80x25,  80, 25, 0 },
  20         { VIDEO_8POINT, 80, 50, 0 },
  21         { VIDEO_80x43,  80, 43, 0 },
  22         { VIDEO_80x28,  80, 28, 0 },
  23         { VIDEO_80x30,  80, 30, 0 },
  24         { VIDEO_80x34,  80, 34, 0 },
  25         { VIDEO_80x60,  80, 60, 0 },
  26 };
  27
  28 static struct mode_info ega_modes[] = {
  29         { VIDEO_80x25,  80, 25, 0 },
  30         { VIDEO_8POINT, 80, 43, 0 },
  31 };
  32
  33 static struct mode_info cga_modes[] = {
  34         { VIDEO_80x25,  80, 25, 0 },
  35 };
  36
  37 static __videocard video_vga;
  38
  39 /* Set basic 80x25 mode */
  40 static u8 vga_set_basic_mode(void)
  41 {
  42         u16 ax;
  43         u8 rows;
  44         u8 mode;
  45
  46 #ifdef CONFIG_VIDEO_400_HACK
  47         if (adapter >= ADAPTER_VGA) {
  48                 asm volatile(INT10
  49                              : : "a" (0x1202), "b" (0x0030)
  50                              : "ecx", "edx", "esi", "edi");
  51         }
  52 #endif
  53
  54         ax = 0x0f00;
  55         asm volatile(INT10
  56                      : "+a" (ax)
  57                      : : "ebx", "ecx", "edx", "esi", "edi");
  58
  59         mode = (u8)ax;
  60
  61         set_fs(0);
  62         rows = rdfs8(0x484);    /* rows minus one */
  63
  64 #ifndef CONFIG_VIDEO_400_HACK
  65         if ((ax == 0x5003 || ax == 0x5007) &&
  66             (rows == 0 || rows == 24))
  67                 return mode;
  68 #endif
  69
  70         if (mode != 3 && mode != 7)
  71                 mode = 3;
  72
  73         /* Set the mode */
  74         ax = mode;
  75         asm volatile(INT10
  76                      : "+a" (ax)
  77                      : : "ebx", "ecx", "edx", "esi", "edi");
  78         do_restore = 1;
  79         return mode;
  80 }
  81
  82 static void vga_set_8font(void)
  83 {
  84         /* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */
  85
  86         /* Set 8x8 font */
  87         asm volatile(INT10 : : "a" (0x1112), "b" (0));
  88
  89         /* Use alternate print screen */
  90         asm volatile(INT10 : : "a" (0x1200), "b" (0x20));
  91
  92         /* Turn off cursor emulation */
  93         asm volatile(INT10 : : "a" (0x1201), "b" (0x34));
  94
  95         /* Cursor is scan lines 6-7 */
  96         asm volatile(INT10 : : "a" (0x0100), "c" (0x0607));
  97 }
  98
  99 static void vga_set_14font(void)
 100 {
 101         /* Set 9x14 font - 80x28 on VGA */
 102
 103         /* Set 9x14 font */
 104         asm volatile(INT10 : : "a" (0x1111), "b" (0));
 105
 106         /* Turn off cursor emulation */
 107         asm volatile(INT10 : : "a" (0x1201), "b" (0x34));
 108
 109         /* Cursor is scan lines 11-12 */
 110         asm volatile(INT10 : : "a" (0x0100), "c" (0x0b0c));
 111 }
 112
 113 static void vga_set_80x43(void)
 114 {
 115         /* Set 80x43 mode on VGA (not EGA) */
 116
 117         /* Set 350 scans */
 118         asm volatile(INT10 : : "a" (0x1201), "b" (0x30));
 119
 120         /* Reset video mode */
 121         asm volatile(INT10 : : "a" (0x0003));
 122
 123         vga_set_8font();
 124 }
 125
 126 /* I/O address of the VGA CRTC */
 127 u16 vga_crtc(void)
 128 {
 129         return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4;
 130 }
 131
 132 static void vga_set_480_scanlines(int lines)
 133 {
 134         u16 crtc;               /* CRTC base address */
 135         u8  csel;               /* CRTC miscellaneous output register */
 136         u8  ovfw;               /* CRTC overflow register */
 137         int end = lines-1;
 138
 139         crtc = vga_crtc();
 140
 141         ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40);
 142
 143         out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */
 144         out_idx(0x0b, crtc, 0x06); /* Vertical total */
 145         out_idx(ovfw, crtc, 0x07); /* Vertical overflow */
 146         out_idx(0xea, crtc, 0x10); /* Vertical sync start */
 147         out_idx(end,  crtc, 0x12); /* Vertical display end */
 148         out_idx(0xe7, crtc, 0x15); /* Vertical blank start */
 149         out_idx(0x04, crtc, 0x16); /* Vertical blank end */
 150         csel = inb(0x3cc);
 151         csel &= 0x0d;
 152         csel |= 0xe2;
 153         outb(csel, 0x3c2);
 154 }
 155
 156 static void vga_set_80x30(void)
 157 {
 158         vga_set_480_scanlines(30*16);
 159 }
 160
 161 static void vga_set_80x34(void)
 162 {
 163         vga_set_14font();
 164         vga_set_480_scanlines(34*14);
 165 }
 166
 167 static void vga_set_80x60(void)
 168 {
 169         vga_set_8font();
 170         vga_set_480_scanlines(60*8);
 171 }
 172
 173 static int vga_set_mode(struct mode_info *mode)
 174 {
 175         /* Set the basic mode */
 176         vga_set_basic_mode();
 177
 178         /* Override a possibly broken BIOS */
 179         force_x = mode->x;
 180         force_y = mode->y;
 181
 182         switch (mode->mode) {
 183         case VIDEO_80x25:
 184                 break;
 185         case VIDEO_8POINT:
 186                 vga_set_8font();
 187                 break;
 188         case VIDEO_80x43:
 189                 vga_set_80x43();
 190                 break;
 191         case VIDEO_80x28:
 192                 vga_set_14font();
 193                 break;
 194         case VIDEO_80x30:
 195                 vga_set_80x30();
 196                 break;
 197         case VIDEO_80x34:
 198                 vga_set_80x34();
 199                 break;
 200         case VIDEO_80x60:
 201                 vga_set_80x60();
 202                 break;
 203         }
 204
 205         return 0;
 206 }
 207
 208 /*
 209  * Note: this probe includes basic information required by all
 210  * systems.  It should be executed first, by making sure
 211  * video-vga.c is listed first in the Makefile.
 212  */
 213 static int vga_probe(void)
 214 {
 215         u16 ega_bx;
 216
 217         static const char *card_name[] = {
 218                 "CGA/MDA/HGC", "EGA", "VGA"
 219         };
 220         static struct mode_info *mode_lists[] = {
 221                 cga_modes,
 222                 ega_modes,
 223                 vga_modes,
 224         };
 225         static int mode_count[] = {
 226                 sizeof(cga_modes)/sizeof(struct mode_info),
 227                 sizeof(ega_modes)/sizeof(struct mode_info),
 228                 sizeof(vga_modes)/sizeof(struct mode_info),
 229         };
 230         u8 vga_flag;
 231
 232         asm(INT10
 233             : "=b" (ega_bx)
 234             : "a" (0x1200), "b" (0x10) /* Check EGA/VGA */
 235             : "ecx", "edx", "esi", "edi");
 236
 237 #ifndef _WAKEUP
 238         boot_params.screen_info.orig_video_ega_bx = ega_bx;
 239 #endif
 240
 241         /* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */
 242         if ((u8)ega_bx != 0x10) {
 243                 /* EGA/VGA */
 244                 asm(INT10
 245                     : "=a" (vga_flag)
 246                     : "a" (0x1a00)
 247                     : "ebx", "ecx", "edx", "esi", "edi");
 248
 249                 if (vga_flag == 0x1a) {
 250                         adapter = ADAPTER_VGA;
 251 #ifndef _WAKEUP
 252                         boot_params.screen_info.orig_video_isVGA = 1;
 253 #endif
 254                 } else {
 255                         adapter = ADAPTER_EGA;
 256                 }
 257         } else {
 258                 adapter = ADAPTER_CGA;
 259         }
 260
 261         video_vga.modes = mode_lists[adapter];
 262         video_vga.card_name = card_name[adapter];
 263         return mode_count[adapter];
 264 }
 265
 266 static __videocard video_vga = {
 267         .card_name      = "VGA",
 268         .probe          = vga_probe,
 269         .set_mode       = vga_set_mode,
 270 };