arch/x86/boot/video.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  * Select video mode
  13  */
  14
  15 #include "boot.h"
  16 #include "video.h"
  17 #include "vesa.h"
  18
  19 static void store_cursor_position(void)
  20 {
  21         u16 curpos;
  22         u16 ax, bx;
  23
  24         ax = 0x0300;
  25         bx = 0;
  26         asm(INT10
  27             : "=d" (curpos), "+a" (ax), "+b" (bx)
  28             : : "ecx", "esi", "edi");
  29
  30         boot_params.screen_info.orig_x = curpos;
  31         boot_params.screen_info.orig_y = curpos >> 8;
  32 }
  33
  34 static void store_video_mode(void)
  35 {
  36         u16 ax, page;
  37
  38         /* N.B.: the saving of the video page here is a bit silly,
  39            since we pretty much assume page 0 everywhere. */
  40         ax = 0x0f00;
  41         asm(INT10
  42             : "+a" (ax), "=b" (page)
  43             : : "ecx", "edx", "esi", "edi");
  44
  45         /* Not all BIOSes are clean with respect to the top bit */
  46         boot_params.screen_info.orig_video_mode = ax & 0x7f;
  47         boot_params.screen_info.orig_video_page = page >> 8;
  48 }
  49
  50 /*
  51  * Store the video mode parameters for later usage by the kernel.
  52  * This is done by asking the BIOS except for the rows/columns
  53  * parameters in the default 80x25 mode -- these are set directly,
  54  * because some very obscure BIOSes supply insane values.
  55  */
  56 static void store_mode_params(void)
  57 {
  58         u16 font_size;
  59         int x, y;
  60
  61         /* For graphics mode, it is up to the mode-setting driver
  62            (currently only video-vesa.c) to store the parameters */
  63         if (graphic_mode)
  64                 return;
  65
  66         store_cursor_position();
  67         store_video_mode();
  68
  69         if (boot_params.screen_info.orig_video_mode == 0x07) {
  70                 /* MDA, HGC, or VGA in monochrome mode */
  71                 video_segment = 0xb000;
  72         } else {
  73                 /* CGA, EGA, VGA and so forth */
  74                 video_segment = 0xb800;
  75         }
  76
  77         set_fs(0);
  78         font_size = rdfs16(0x485); /* Font size, BIOS area */
  79         boot_params.screen_info.orig_video_points = font_size;
  80
  81         x = rdfs16(0x44a);
  82         y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
  83
  84         if (force_x)
  85                 x = force_x;
  86         if (force_y)
  87                 y = force_y;
  88
  89         boot_params.screen_info.orig_video_cols  = x;
  90         boot_params.screen_info.orig_video_lines = y;
  91 }
  92
  93 static unsigned int get_entry(void)
  94 {
  95         char entry_buf[4];
  96         int i, len = 0;
  97         int key;
  98         unsigned int v;
  99
 100         do {
 101                 key = getchar();
 102
 103                 if (key == '\b') {
 104                         if (len > 0) {
 105                                 puts("\b \b");
 106                                 len--;
 107                         }
 108                 } else if ((key >= '0' && key <= '9') ||
 109                            (key >= 'A' && key <= 'Z') ||
 110                            (key >= 'a' && key <= 'z')) {
 111                         if (len < sizeof entry_buf) {
 112                                 entry_buf[len++] = key;
 113                                 putchar(key);
 114                         }
 115                 }
 116         } while (key != '\r');
 117         putchar('\n');
 118
 119         if (len == 0)
 120                 return VIDEO_CURRENT_MODE; /* Default */
 121
 122         v = 0;
 123         for (i = 0; i < len; i++) {
 124                 v <<= 4;
 125                 key = entry_buf[i] | 0x20;
 126                 v += (key > '9') ? key-'a'+10 : key-'0';
 127         }
 128
 129         return v;
 130 }
 131
 132 static void display_menu(void)
 133 {
 134         struct card_info *card;
 135         struct mode_info *mi;
 136         char ch;
 137         int i;
 138         int nmodes;
 139         int modes_per_line;
 140         int col;
 141
 142         nmodes = 0;
 143         for (card = video_cards; card < video_cards_end; card++)
 144                 nmodes += card->nmodes;
 145
 146         modes_per_line = 1;
 147         if (nmodes >= 20)
 148                 modes_per_line = 3;
 149
 150         for (col = 0; col < modes_per_line; col++)
 151                 puts("Mode: Resolution:  Type: ");
 152         putchar('\n');
 153
 154         col = 0;
 155         ch = '0';
 156         for (card = video_cards; card < video_cards_end; card++) {
 157                 mi = card->modes;
 158                 for (i = 0; i < card->nmodes; i++, mi++) {
 159                         char resbuf[32];
 160                         int visible = mi->x && mi->y;
 161                         u16 mode_id = mi->mode ? mi->mode :
 162                                 (mi->y << 8)+mi->x;
 163
 164                         if (!visible)
 165                                 continue; /* Hidden mode */
 166
 167                         if (mi->depth)
 168                                 sprintf(resbuf, "%dx%d", mi->y, mi->depth);
 169                         else
 170                                 sprintf(resbuf, "%d", mi->y);
 171
 172                         printf("%c %03X %4dx%-7s %-6s",
 173                                ch, mode_id, mi->x, resbuf, card->card_name);
 174                         col++;
 175                         if (col >= modes_per_line) {
 176                                 putchar('\n');
 177                                 col = 0;
 178                         }
 179
 180                         if (ch == '9')
 181                                 ch = 'a';
 182                         else if (ch == 'z' || ch == ' ')
 183                                 ch = ' '; /* Out of keys... */
 184                         else
 185                                 ch++;
 186                 }
 187         }
 188         if (col)
 189                 putchar('\n');
 190 }
 191
 192 #define H(x)    ((x)-'a'+10)
 193 #define SCAN    ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
 194
 195 static unsigned int mode_menu(void)
 196 {
 197         int key;
 198         unsigned int sel;
 199
 200         puts("Press <ENTER> to see video modes available, "
 201              "<SPACE> to continue, or wait 30 sec\n");
 202
 203         kbd_flush();
 204         while (1) {
 205                 key = getchar_timeout();
 206                 if (key == ' ' || key == 0)
 207                         return VIDEO_CURRENT_MODE; /* Default */
 208                 if (key == '\r')
 209                         break;
 210                 putchar('\a');  /* Beep! */
 211         }
 212
 213
 214         for (;;) {
 215                 display_menu();
 216
 217                 puts("Enter a video mode or \"scan\" to scan for "
 218                      "additional modes: ");
 219                 sel = get_entry();
 220                 if (sel != SCAN)
 221                         return sel;
 222
 223                 probe_cards(1);
 224         }
 225 }
 226
 227 #ifdef CONFIG_VIDEO_RETAIN
 228 /* Save screen content to the heap */
 229 struct saved_screen {
 230         int x, y;
 231         int curx, cury;
 232         u16 *data;
 233 } saved;
 234
 235 static void save_screen(void)
 236 {
 237         /* Should be called after store_mode_params() */
 238         saved.x = boot_params.screen_info.orig_video_cols;
 239         saved.y = boot_params.screen_info.orig_video_lines;
 240         saved.curx = boot_params.screen_info.orig_x;
 241         saved.cury = boot_params.screen_info.orig_y;
 242
 243         if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
 244                 return;         /* Not enough heap to save the screen */
 245
 246         saved.data = GET_HEAP(u16, saved.x*saved.y);
 247
 248         set_fs(video_segment);
 249         copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
 250 }
 251
 252 static void restore_screen(void)
 253 {
 254         /* Should be called after store_mode_params() */
 255         int xs = boot_params.screen_info.orig_video_cols;
 256         int ys = boot_params.screen_info.orig_video_lines;
 257         int y;
 258         addr_t dst = 0;
 259         u16 *src = saved.data;
 260         u16 ax, bx, dx;
 261
 262         if (graphic_mode)
 263                 return;         /* Can't restore onto a graphic mode */
 264
 265         if (!src)
 266                 return;         /* No saved screen contents */
 267
 268         /* Restore screen contents */
 269
 270         set_fs(video_segment);
 271         for (y = 0; y < ys; y++) {
 272                 int npad;
 273
 274                 if (y < saved.y) {
 275                         int copy = (xs < saved.x) ? xs : saved.x;
 276                         copy_to_fs(dst, src, copy*sizeof(u16));
 277                         dst += copy*sizeof(u16);
 278                         src += saved.x;
 279                         npad = (xs < saved.x) ? 0 : xs-saved.x;
 280                 } else {
 281                         npad = xs;
 282                 }
 283
 284                 /* Writes "npad" blank characters to
 285                    video_segment:dst and advances dst */
 286                 asm volatile("pushw %%es ; "
 287                              "movw %2,%%es ; "
 288                              "shrw %%cx ; "
 289                              "jnc 1f ; "
 290                              "stosw \n\t"
 291                              "1: rep;stosl ; "
 292                              "popw %%es"
 293                              : "+D" (dst), "+c" (npad)
 294                              : "bdS" (video_segment),
 295                                "a" (0x07200720));
 296         }
 297
 298         /* Restore cursor position */
 299         ax = 0x0200;            /* Set cursor position */
 300         bx = 0;                 /* Page number (<< 8) */
 301         dx = (saved.cury << 8)+saved.curx;
 302         asm volatile(INT10
 303                      : "+a" (ax), "+b" (bx), "+d" (dx)
 304                      : : "ecx", "esi", "edi");
 305 }
 306 #else
 307 #define save_screen()           ((void)0)
 308 #define restore_screen()        ((void)0)
 309 #endif
 310
 311 void set_video(void)
 312 {
 313         u16 mode = boot_params.hdr.vid_mode;
 314
 315         RESET_HEAP();
 316
 317         store_mode_params();
 318         save_screen();
 319         probe_cards(0);
 320
 321         for (;;) {
 322                 if (mode == ASK_VGA)
 323                         mode = mode_menu();
 324
 325                 if (!set_mode(mode))
 326                         break;
 327
 328                 printf("Undefined video mode number: %x\n", mode);
 329                 mode = ASK_VGA;
 330         }
 331         boot_params.hdr.vid_mode = mode;
 332         vesa_store_edid();
 333         store_mode_params();
 334
 335         if (do_restore)
 336                 restore_screen();
 337 }