1 // SPDX-License-Identifier: GPL-2.0-only 2 /* -*- linux-c -*- ------------------------------------------------------- * 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * Copyright 2007 rPath, Inc. - All Rights Reserved 6 * Copyright 2009 Intel Corporation; author H. Peter Anvin 7 * 8 * ----------------------------------------------------------------------- */ 9 10 /* 11 * Common all-VGA modes 12 */ 13 14 #include "boot.h" 15 #include "video.h" 16 17 static struct mode_info vga_modes[] = { 18 { VIDEO_80x25, 80, 25, 0 }, 19 { VIDEO_8POINT, 80, 50, 0 }, 20 { VIDEO_80x43, 80, 43, 0 }, 21 { VIDEO_80x28, 80, 28, 0 }, 22 { VIDEO_80x30, 80, 30, 0 }, 23 { VIDEO_80x34, 80, 34, 0 }, 24 { VIDEO_80x60, 80, 60, 0 }, 25 }; 26 27 static struct mode_info ega_modes[] = { 28 { VIDEO_80x25, 80, 25, 0 }, 29 { VIDEO_8POINT, 80, 43, 0 }, 30 }; 31 32 static struct mode_info cga_modes[] = { 33 { VIDEO_80x25, 80, 25, 0 }, 34 }; 35 36 static __videocard video_vga; 37 38 /* Set basic 80x25 mode */ 39 static u8 vga_set_basic_mode(void) 40 { 41 struct biosregs ireg, oreg; 42 u8 mode; 43 44 initregs(&ireg); 45 46 /* Query current mode */ 47 ireg.ax = 0x0f00; 48 intcall(0x10, &ireg, &oreg); 49 mode = oreg.al; 50 51 if (mode != 3 && mode != 7) 52 mode = 3; 53 54 /* Set the mode */ 55 ireg.ax = mode; /* AH=0: set mode */ 56 intcall(0x10, &ireg, NULL); 57 do_restore = 1; 58 return mode; 59 } 60 61 static void vga_set_8font(void) 62 { 63 /* Set 8x8 font - 80x43 on EGA, 80x50 on VGA */ 64 struct biosregs ireg; 65 66 initregs(&ireg); 67 68 /* Set 8x8 font */ 69 ireg.ax = 0x1112; 70 /* ireg.bl = 0; */ 71 intcall(0x10, &ireg, NULL); 72 73 /* Use alternate print screen */ 74 ireg.ax = 0x1200; 75 ireg.bl = 0x20; 76 intcall(0x10, &ireg, NULL); 77 78 /* Turn off cursor emulation */ 79 ireg.ax = 0x1201; 80 ireg.bl = 0x34; 81 intcall(0x10, &ireg, NULL); 82 83 /* Cursor is scan lines 6-7 */ 84 ireg.ax = 0x0100; 85 ireg.cx = 0x0607; 86 intcall(0x10, &ireg, NULL); 87 } 88 89 static void vga_set_14font(void) 90 { 91 /* Set 9x14 font - 80x28 on VGA */ 92 struct biosregs ireg; 93 94 initregs(&ireg); 95 96 /* Set 9x14 font */ 97 ireg.ax = 0x1111; 98 /* ireg.bl = 0; */ 99 intcall(0x10, &ireg, NULL); 100 101 /* Turn off cursor emulation */ 102 ireg.ax = 0x1201; 103 ireg.bl = 0x34; 104 intcall(0x10, &ireg, NULL); 105 106 /* Cursor is scan lines 11-12 */ 107 ireg.ax = 0x0100; 108 ireg.cx = 0x0b0c; 109 intcall(0x10, &ireg, NULL); 110 } 111 112 static void vga_set_80x43(void) 113 { 114 /* Set 80x43 mode on VGA (not EGA) */ 115 struct biosregs ireg; 116 117 initregs(&ireg); 118 119 /* Set 350 scans */ 120 ireg.ax = 0x1201; 121 ireg.bl = 0x30; 122 intcall(0x10, &ireg, NULL); 123 124 /* Reset video mode */ 125 ireg.ax = 0x0003; 126 intcall(0x10, &ireg, NULL); 127 128 vga_set_8font(); 129 } 130 131 /* I/O address of the VGA CRTC */ 132 u16 vga_crtc(void) 133 { 134 return (inb(0x3cc) & 1) ? 0x3d4 : 0x3b4; 135 } 136 137 static void vga_set_480_scanlines(void) 138 { 139 u16 crtc; /* CRTC base address */ 140 u8 csel; /* CRTC miscellaneous output register */ 141 142 crtc = vga_crtc(); 143 144 out_idx(0x0c, crtc, 0x11); /* Vertical sync end, unlock CR0-7 */ 145 out_idx(0x0b, crtc, 0x06); /* Vertical total */ 146 out_idx(0x3e, crtc, 0x07); /* Vertical overflow */ 147 out_idx(0xea, crtc, 0x10); /* Vertical sync start */ 148 out_idx(0xdf, crtc, 0x12); /* Vertical display end */ 149 out_idx(0xe7, crtc, 0x15); /* Vertical blank start */ 150 out_idx(0x04, crtc, 0x16); /* Vertical blank end */ 151 csel = inb(0x3cc); 152 csel &= 0x0d; 153 csel |= 0xe2; 154 outb(csel, 0x3c2); 155 } 156 157 static void vga_set_vertical_end(int lines) 158 { 159 u16 crtc; /* CRTC base address */ 160 u8 ovfw; /* CRTC overflow register */ 161 int end = lines-1; 162 163 crtc = vga_crtc(); 164 165 ovfw = 0x3c | ((end >> (8-1)) & 0x02) | ((end >> (9-6)) & 0x40); 166 167 out_idx(ovfw, crtc, 0x07); /* Vertical overflow */ 168 out_idx(end, crtc, 0x12); /* Vertical display end */ 169 } 170 171 static void vga_set_80x30(void) 172 { 173 vga_set_480_scanlines(); 174 vga_set_vertical_end(30*16); 175 } 176 177 static void vga_set_80x34(void) 178 { 179 vga_set_480_scanlines(); 180 vga_set_14font(); 181 vga_set_vertical_end(34*14); 182 } 183 184 static void vga_set_80x60(void) 185 { 186 vga_set_480_scanlines(); 187 vga_set_8font(); 188 vga_set_vertical_end(60*8); 189 } 190 191 static int vga_set_mode(struct mode_info *mode) 192 { 193 /* Set the basic mode */ 194 vga_set_basic_mode(); 195 196 /* Override a possibly broken BIOS */ 197 force_x = mode->x; 198 force_y = mode->y; 199 200 switch (mode->mode) { 201 case VIDEO_80x25: 202 break; 203 case VIDEO_8POINT: 204 vga_set_8font(); 205 break; 206 case VIDEO_80x43: 207 vga_set_80x43(); 208 break; 209 case VIDEO_80x28: 210 vga_set_14font(); 211 break; 212 case VIDEO_80x30: 213 vga_set_80x30(); 214 break; 215 case VIDEO_80x34: 216 vga_set_80x34(); 217 break; 218 case VIDEO_80x60: 219 vga_set_80x60(); 220 break; 221 } 222 223 return 0; 224 } 225 226 /* 227 * Note: this probe includes basic information required by all 228 * systems. It should be executed first, by making sure 229 * video-vga.c is listed first in the Makefile. 230 */ 231 static int vga_probe(void) 232 { 233 static const char *card_name[] = { 234 "CGA/MDA/HGC", "EGA", "VGA" 235 }; 236 static struct mode_info *mode_lists[] = { 237 cga_modes, 238 ega_modes, 239 vga_modes, 240 }; 241 static int mode_count[] = { 242 ARRAY_SIZE(cga_modes), 243 ARRAY_SIZE(ega_modes), 244 ARRAY_SIZE(vga_modes), 245 }; 246 247 struct biosregs ireg, oreg; 248 249 initregs(&ireg); 250 251 ireg.ax = 0x1200; 252 ireg.bl = 0x10; /* Check EGA/VGA */ 253 intcall(0x10, &ireg, &oreg); 254 255 #ifndef _WAKEUP 256 boot_params.screen_info.orig_video_ega_bx = oreg.bx; 257 #endif 258 259 /* If we have MDA/CGA/HGC then BL will be unchanged at 0x10 */ 260 if (oreg.bl != 0x10) { 261 /* EGA/VGA */ 262 ireg.ax = 0x1a00; 263 intcall(0x10, &ireg, &oreg); 264 265 if (oreg.al == 0x1a) { 266 adapter = ADAPTER_VGA; 267 #ifndef _WAKEUP 268 boot_params.screen_info.orig_video_isVGA = 1; 269 #endif 270 } else { 271 adapter = ADAPTER_EGA; 272 } 273 } else { 274 adapter = ADAPTER_CGA; 275 } 276 277 video_vga.modes = mode_lists[adapter]; 278 video_vga.card_name = card_name[adapter]; 279 return mode_count[adapter]; 280 } 281 282 static __videocard video_vga = { 283 .card_name = "VGA", 284 .probe = vga_probe, 285 .set_mode = vga_set_mode, 286 }; 287