arch/i386/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  * arch/i386/boot/video.c
  13  *
  14  * Select video mode
  15  */
  16
  17 #include "boot.h"
  18 #include "video.h"
  19 #include "vesa.h"
  20
  21 /*
  22  * Mode list variables
  23  */
  24 static struct card_info cards[];    /* List of cards to probe for */
  25
  26 /*
  27  * Common variables
  28  */
  29 int adapter;                    /* 0=CGA/MDA/HGC, 1=EGA, 2=VGA+ */
  30 u16 video_segment;
  31 int force_x, force_y;   /* Don't query the BIOS for cols/rows */
  32
  33 int do_restore = 0;     /* Screen contents changed during mode flip */
  34 int graphic_mode;       /* Graphic mode with linear frame buffer */
  35
  36 static void store_cursor_position(void)
  37 {
  38         u16 curpos;
  39         u16 ax, bx;
  40
  41         ax = 0x0300;
  42         bx = 0;
  43         asm(INT10
  44             : "=d" (curpos), "+a" (ax), "+b" (bx)
  45             : : "ecx", "esi", "edi");
  46
  47         boot_params.screen_info.orig_x = curpos;
  48         boot_params.screen_info.orig_y = curpos >> 8;
  49 }
  50
  51 static void store_video_mode(void)
  52 {
  53         u16 ax, page;
  54
  55         /* N.B.: the saving of the video page here is a bit silly,
  56            since we pretty much assume page 0 everywhere. */
  57         ax = 0x0f00;
  58         asm(INT10
  59             : "+a" (ax), "=b" (page)
  60             : : "ecx", "edx", "esi", "edi");
  61
  62         /* Not all BIOSes are clean with respect to the top bit */
  63         boot_params.screen_info.orig_video_mode = ax & 0x7f;
  64         boot_params.screen_info.orig_video_page = page >> 8;
  65 }
  66
  67 /*
  68  * Store the video mode parameters for later usage by the kernel.
  69  * This is done by asking the BIOS except for the rows/columns
  70  * parameters in the default 80x25 mode -- these are set directly,
  71  * because some very obscure BIOSes supply insane values.
  72  */
  73 static void store_mode_params(void)
  74 {
  75         u16 font_size;
  76         int x, y;
  77
  78         /* For graphics mode, it is up to the mode-setting driver
  79            (currently only video-vesa.c) to store the parameters */
  80         if (graphic_mode)
  81                 return;
  82
  83         store_cursor_position();
  84         store_video_mode();
  85
  86         if (boot_params.screen_info.orig_video_mode == 0x07) {
  87                 /* MDA, HGC, or VGA in monochrome mode */
  88                 video_segment = 0xb000;
  89         } else {
  90                 /* CGA, EGA, VGA and so forth */
  91                 video_segment = 0xb800;
  92         }
  93
  94         set_fs(0);
  95         font_size = rdfs16(0x485); /* Font size, BIOS area */
  96         boot_params.screen_info.orig_video_points = font_size;
  97
  98         x = rdfs16(0x44a);
  99         y = (adapter == ADAPTER_CGA) ? 25 : rdfs8(0x484)+1;
 100
 101         if (force_x)
 102                 x = force_x;
 103         if (force_y)
 104                 y = force_y;
 105
 106         boot_params.screen_info.orig_video_cols  = x;
 107         boot_params.screen_info.orig_video_lines = y;
 108 }
 109
 110 /* Probe the video drivers and have them generate their mode lists. */
 111 static void probe_cards(int unsafe)
 112 {
 113         struct card_info *card;
 114         static u8 probed[2];
 115
 116         if (probed[unsafe])
 117                 return;
 118
 119         probed[unsafe] = 1;
 120
 121         for (card = video_cards; card < video_cards_end; card++) {
 122                 if (card->unsafe == unsafe) {
 123                         if (card->probe)
 124                                 card->nmodes = card->probe();
 125                         else
 126                                 card->nmodes = 0;
 127                 }
 128         }
 129 }
 130
 131 /* Test if a mode is defined */
 132 int mode_defined(u16 mode)
 133 {
 134         struct card_info *card;
 135         struct mode_info *mi;
 136         int i;
 137
 138         for (card = video_cards; card < video_cards_end; card++) {
 139                 mi = card->modes;
 140                 for (i = 0; i < card->nmodes; i++, mi++) {
 141                         if (mi->mode == mode)
 142                                 return 1;
 143                 }
 144         }
 145
 146         return 0;
 147 }
 148
 149 /* Set mode (without recalc) */
 150 static int raw_set_mode(u16 mode)
 151 {
 152         int nmode, i;
 153         struct card_info *card;
 154         struct mode_info *mi;
 155
 156         /* Drop the recalc bit if set */
 157         mode &= ~VIDEO_RECALC;
 158
 159         /* Scan for mode based on fixed ID, position, or resolution */
 160         nmode = 0;
 161         for (card = video_cards; card < video_cards_end; card++) {
 162                 mi = card->modes;
 163                 for (i = 0; i < card->nmodes; i++, mi++) {
 164                         int visible = mi->x || mi->y;
 165
 166                         if ((mode == nmode && visible) ||
 167                             mode == mi->mode ||
 168                             mode == (mi->y << 8)+mi->x)
 169                                 return card->set_mode(mi);
 170
 171                         if (visible)
 172                                 nmode++;
 173                 }
 174         }
 175
 176         /* Nothing found?  Is it an "exceptional" (unprobed) mode? */
 177         for (card = video_cards; card < video_cards_end; card++) {
 178                 if (mode >= card->xmode_first &&
 179                     mode < card->xmode_first+card->xmode_n) {
 180                         struct mode_info mix;
 181                         mix.mode = mode;
 182                         mix.x = mix.y = 0;
 183                         return card->set_mode(&mix);
 184                 }
 185         }
 186
 187         /* Otherwise, failure... */
 188         return -1;
 189 }
 190
 191 /*
 192  * Recalculate the vertical video cutoff (hack!)
 193  */
 194 static void vga_recalc_vertical(void)
 195 {
 196         unsigned int font_size, rows;
 197         u16 crtc;
 198         u8 pt, ov;
 199
 200         set_fs(0);
 201         font_size = rdfs8(0x485); /* BIOS: font size (pixels) */
 202         rows = force_y ? force_y : rdfs8(0x484)+1; /* Text rows */
 203
 204         rows *= font_size;      /* Visible scan lines */
 205         rows--;                 /* ... minus one */
 206
 207         crtc = vga_crtc();
 208
 209         pt = in_idx(crtc, 0x11);
 210         pt &= ~0x80;            /* Unlock CR0-7 */
 211         out_idx(pt, crtc, 0x11);
 212
 213         out_idx((u8)rows, crtc, 0x12); /* Lower height register */
 214
 215         ov = in_idx(crtc, 0x07); /* Overflow register */
 216         ov &= 0xbd;
 217         ov |= (rows >> (8-1)) & 0x02;
 218         ov |= (rows >> (9-6)) & 0x40;
 219         out_idx(ov, crtc, 0x07);
 220 }
 221
 222 /* Set mode (with recalc if specified) */
 223 static int set_mode(u16 mode)
 224 {
 225         int rv;
 226
 227         /* Very special mode numbers... */
 228         if (mode == VIDEO_CURRENT_MODE)
 229                 return 0;       /* Nothing to do... */
 230         else if (mode == NORMAL_VGA)
 231                 mode = VIDEO_80x25;
 232         else if (mode == EXTENDED_VGA)
 233                 mode = VIDEO_8POINT;
 234
 235         rv = raw_set_mode(mode);
 236         if (rv)
 237                 return rv;
 238
 239         if (mode & VIDEO_RECALC)
 240                 vga_recalc_vertical();
 241
 242         return 0;
 243 }
 244
 245 static unsigned int get_entry(void)
 246 {
 247         char entry_buf[4];
 248         int i, len = 0;
 249         int key;
 250         unsigned int v;
 251
 252         do {
 253                 key = getchar();
 254
 255                 if (key == '\b') {
 256                         if (len > 0) {
 257                                 puts("\b \b");
 258                                 len--;
 259                         }
 260                 } else if ((key >= '0' && key <= '9') ||
 261                            (key >= 'A' && key <= 'Z') ||
 262                            (key >= 'a' && key <= 'z')) {
 263                         if (len < sizeof entry_buf) {
 264                                 entry_buf[len++] = key;
 265                                 putchar(key);
 266                         }
 267                 }
 268         } while (key != '\r');
 269         putchar('\n');
 270
 271         if (len == 0)
 272                 return VIDEO_CURRENT_MODE; /* Default */
 273
 274         v = 0;
 275         for (i = 0; i < len; i++) {
 276                 v <<= 4;
 277                 key = entry_buf[i] | 0x20;
 278                 v += (key > '9') ? key-'a'+10 : key-'0';
 279         }
 280
 281         return v;
 282 }
 283
 284 static void display_menu(void)
 285 {
 286         struct card_info *card;
 287         struct mode_info *mi;
 288         char ch;
 289         int i;
 290
 291         puts("Mode:    COLSxROWS:\n");
 292
 293         ch = '0';
 294         for (card = video_cards; card < video_cards_end; card++) {
 295                 mi = card->modes;
 296                 for (i = 0; i < card->nmodes; i++, mi++) {
 297                         int visible = mi->x && mi->y;
 298                         u16 mode_id = mi->mode ? mi->mode :
 299                                 (mi->y << 8)+mi->x;
 300
 301                         if (!visible)
 302                                 continue; /* Hidden mode */
 303
 304                         printf("%c  %04X  %3dx%-3d  %s\n",
 305                                ch, mode_id, mi->x, mi->y, card->card_name);
 306
 307                         if (ch == '9')
 308                                 ch = 'a';
 309                         else if (ch == 'z' || ch == ' ')
 310                                 ch = ' '; /* Out of keys... */
 311                         else
 312                                 ch++;
 313                 }
 314         }
 315 }
 316
 317 #define H(x)    ((x)-'a'+10)
 318 #define SCAN    ((H('s')<<12)+(H('c')<<8)+(H('a')<<4)+H('n'))
 319
 320 static unsigned int mode_menu(void)
 321 {
 322         int key;
 323         unsigned int sel;
 324
 325         puts("Press <ENTER> to see video modes available, "
 326              "<SPACE> to continue, or wait 30 sec\n");
 327
 328         kbd_flush();
 329         while (1) {
 330                 key = getchar_timeout();
 331                 if (key == ' ' || key == 0)
 332                         return VIDEO_CURRENT_MODE; /* Default */
 333                 if (key == '\r')
 334                         break;
 335                 putchar('\a');  /* Beep! */
 336         }
 337
 338
 339         for (;;) {
 340                 display_menu();
 341
 342                 puts("Enter a video mode or \"scan\" to scan for "
 343                      "additional modes: ");
 344                 sel = get_entry();
 345                 if (sel != SCAN)
 346                         return sel;
 347
 348                 probe_cards(1);
 349         }
 350 }
 351
 352 #ifdef CONFIG_VIDEO_RETAIN
 353 /* Save screen content to the heap */
 354 struct saved_screen {
 355         int x, y;
 356         int curx, cury;
 357         u16 *data;
 358 } saved;
 359
 360 static void save_screen(void)
 361 {
 362         /* Should be called after store_mode_params() */
 363         saved.x = boot_params.screen_info.orig_video_cols;
 364         saved.y = boot_params.screen_info.orig_video_lines;
 365         saved.curx = boot_params.screen_info.orig_x;
 366         saved.cury = boot_params.screen_info.orig_y;
 367
 368         if (heap_free() < saved.x*saved.y*sizeof(u16)+512)
 369                 return;         /* Not enough heap to save the screen */
 370
 371         saved.data = GET_HEAP(u16, saved.x*saved.y);
 372
 373         set_fs(video_segment);
 374         copy_from_fs(saved.data, 0, saved.x*saved.y*sizeof(u16));
 375 }
 376
 377 static void restore_screen(void)
 378 {
 379         /* Should be called after store_mode_params() */
 380         int xs = boot_params.screen_info.orig_video_cols;
 381         int ys = boot_params.screen_info.orig_video_lines;
 382         int y;
 383         addr_t dst = 0;
 384         u16 *src = saved.data;
 385         u16 ax, bx, dx;
 386
 387         if (graphic_mode)
 388                 return;         /* Can't restore onto a graphic mode */
 389
 390         if (!src)
 391                 return;         /* No saved screen contents */
 392
 393         /* Restore screen contents */
 394
 395         set_fs(video_segment);
 396         for (y = 0; y < ys; y++) {
 397                 int npad;
 398
 399                 if (y < saved.y) {
 400                         int copy = (xs < saved.x) ? xs : saved.x;
 401                         copy_to_fs(dst, src, copy*sizeof(u16));
 402                         dst += copy*sizeof(u16);
 403                         src += saved.x;
 404                         npad = (xs < saved.x) ? 0 : xs-saved.x;
 405                 } else {
 406                         npad = xs;
 407                 }
 408
 409                 /* Writes "npad" blank characters to
 410                    video_segment:dst and advances dst */
 411                 asm volatile("pushw %%es ; "
 412                              "movw %2,%%es ; "
 413                              "shrw %%cx ; "
 414                              "jnc 1f ; "
 415                              "stosw \n\t"
 416                              "1: rep;stosl ; "
 417                              "popw %%es"
 418                              : "+D" (dst), "+c" (npad)
 419                              : "bdS" (video_segment),
 420                                "a" (0x07200720));
 421         }
 422
 423         /* Restore cursor position */
 424         ax = 0x0200;            /* Set cursor position */
 425         bx = 0;                 /* Page number (<< 8) */
 426         dx = (saved.cury << 8)+saved.curx;
 427         asm volatile(INT10
 428                      : "+a" (ax), "+b" (bx), "+d" (dx)
 429                      : : "ecx", "esi", "edi");
 430 }
 431 #else
 432 #define save_screen()           ((void)0)
 433 #define restore_screen()        ((void)0)
 434 #endif
 435
 436 void set_video(void)
 437 {
 438         u16 mode = boot_params.hdr.vid_mode;
 439
 440         RESET_HEAP();
 441
 442         store_mode_params();
 443         save_screen();
 444         probe_cards(0);
 445
 446         for (;;) {
 447                 if (mode == ASK_VGA)
 448                         mode = mode_menu();
 449
 450                 if (!set_mode(mode))
 451                         break;
 452
 453                 printf("Undefined video mode number: %x\n", mode);
 454                 mode = ASK_VGA;
 455         }
 456         vesa_store_edid();
 457         store_mode_params();
 458
 459         if (do_restore)
 460                 restore_screen();
 461 }