hw/display/edid-generate.c

   1 /*
   2  * QEMU EDID generator.
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  * See the COPYING file in the top-level directory.
   6  */
   7 #include "qemu/osdep.h"
   8 #include "qemu/bswap.h"
   9 #include "hw/display/edid.h"
  10
  11 static const struct edid_mode {
  12     uint32_t xres;
  13     uint32_t yres;
  14     uint32_t byte;
  15     uint32_t xtra3;
  16     uint32_t bit;
  17     uint32_t dta;
  18 } modes[] = {
  19     /* dea/dta extension timings (all @ 50 Hz) */
  20     { .xres = 5120,   .yres = 2160,   .dta = 125 },
  21     { .xres = 4096,   .yres = 2160,   .dta = 101 },
  22     { .xres = 3840,   .yres = 2160,   .dta =  96 },
  23     { .xres = 2560,   .yres = 1080,   .dta =  89 },
  24     { .xres = 2048,   .yres = 1152 },
  25     { .xres = 1920,   .yres = 1080,   .dta =  31 },
  26
  27     /* additional standard timings 3 (all @ 60Hz) */
  28     { .xres = 1920,   .yres = 1440,   .xtra3 = 11,   .bit = 5 },
  29     { .xres = 1920,   .yres = 1200,   .xtra3 = 10,   .bit = 0 },
  30     { .xres = 1856,   .yres = 1392,   .xtra3 = 10,   .bit = 3 },
  31     { .xres = 1792,   .yres = 1344,   .xtra3 = 10,   .bit = 5 },
  32     { .xres = 1600,   .yres = 1200,   .xtra3 =  9,   .bit = 2 },
  33     { .xres = 1680,   .yres = 1050,   .xtra3 =  9,   .bit = 5 },
  34     { .xres = 1440,   .yres = 1050,   .xtra3 =  8,   .bit = 1 },
  35     { .xres = 1440,   .yres =  900,   .xtra3 =  8,   .bit = 5 },
  36     { .xres = 1360,   .yres =  768,   .xtra3 =  8,   .bit = 7 },
  37     { .xres = 1280,   .yres = 1024,   .xtra3 =  7,   .bit = 1 },
  38     { .xres = 1280,   .yres =  960,   .xtra3 =  7,   .bit = 3 },
  39     { .xres = 1280,   .yres =  768,   .xtra3 =  7,   .bit = 6 },
  40
  41     /* established timings (all @ 60Hz) */
  42     { .xres = 1024,   .yres =  768,   .byte  = 36,   .bit = 3 },
  43     { .xres =  800,   .yres =  600,   .byte  = 35,   .bit = 0 },
  44     { .xres =  640,   .yres =  480,   .byte  = 35,   .bit = 5 },
  45 };
  46
  47 static void edid_ext_dta(uint8_t *dta)
  48 {
  49     dta[0] = 0x02;
  50     dta[1] = 0x03;
  51     dta[2] = 0x05;
  52     dta[3] = 0x00;
  53
  54     /* video data block */
  55     dta[4] = 0x40;
  56 }
  57
  58 static void edid_ext_dta_mode(uint8_t *dta, uint8_t nr)
  59 {
  60     dta[dta[2]] = nr;
  61     dta[2]++;
  62     dta[4]++;
  63 }
  64
  65 static int edid_std_mode(uint8_t *mode, uint32_t xres, uint32_t yres)
  66 {
  67     uint32_t aspect;
  68
  69     if (xres == 0 || yres == 0) {
  70         mode[0] = 0x01;
  71         mode[1] = 0x01;
  72         return 0;
  73
  74     } else if (xres * 10 == yres * 16) {
  75         aspect = 0;
  76     } else if (xres * 3 == yres * 4) {
  77         aspect = 1;
  78     } else if (xres * 4 == yres * 5) {
  79         aspect = 2;
  80     } else if (xres * 9 == yres * 16) {
  81         aspect = 3;
  82     } else {
  83         return -1;
  84     }
  85
  86     if ((xres / 8) - 31 > 255) {
  87         return -1;
  88     }
  89
  90     mode[0] = (xres / 8) - 31;
  91     mode[1] = ((aspect << 6) | (60 - 60));
  92     return 0;
  93 }
  94
  95 static void edid_fill_modes(uint8_t *edid, uint8_t *xtra3, uint8_t *dta,
  96                             uint32_t maxx, uint32_t maxy)
  97 {
  98     const struct edid_mode *mode;
  99     int std = 38;
 100     int rc, i;
 101
 102     for (i = 0; i < ARRAY_SIZE(modes); i++) {
 103         mode = modes + i;
 104
 105         if ((maxx && mode->xres > maxx) ||
 106             (maxy && mode->yres > maxy)) {
 107             continue;
 108         }
 109
 110         if (mode->byte) {
 111             edid[mode->byte] |= (1 << mode->bit);
 112         } else if (mode->xtra3 && xtra3) {
 113             xtra3[mode->xtra3] |= (1 << mode->bit);
 114         } else if (std < 54) {
 115             rc = edid_std_mode(edid + std, mode->xres, mode->yres);
 116             if (rc == 0) {
 117                 std += 2;
 118             }
 119         }
 120
 121         if (dta && mode->dta) {
 122             edid_ext_dta_mode(dta, mode->dta);
 123         }
 124     }
 125
 126     while (std < 54) {
 127         edid_std_mode(edid + std, 0, 0);
 128         std += 2;
 129     }
 130 }
 131
 132 static void edid_checksum(uint8_t *edid)
 133 {
 134     uint32_t sum = 0;
 135     int i;
 136
 137     for (i = 0; i < 127; i++) {
 138         sum += edid[i];
 139     }
 140     sum &= 0xff;
 141     if (sum) {
 142         edid[127] = 0x100 - sum;
 143     }
 144 }
 145
 146 static void edid_desc_type(uint8_t *desc, uint8_t type)
 147 {
 148     desc[0] = 0;
 149     desc[1] = 0;
 150     desc[2] = 0;
 151     desc[3] = type;
 152     desc[4] = 0;
 153 }
 154
 155 static void edid_desc_text(uint8_t *desc, uint8_t type,
 156                            const char *text)
 157 {
 158     size_t len;
 159
 160     edid_desc_type(desc, type);
 161     memset(desc + 5, ' ', 13);
 162
 163     len = strlen(text);
 164     if (len > 12) {
 165         len = 12;
 166     }
 167     memcpy(desc + 5, text, len);
 168     desc[5 + len] = '\n';
 169 }
 170
 171 static void edid_desc_ranges(uint8_t *desc)
 172 {
 173     edid_desc_type(desc, 0xfd);
 174
 175     /* vertical (50 -> 125 Hz) */
 176     desc[5] =  50;
 177     desc[6] = 125;
 178
 179     /* horizontal (30 -> 160 kHz) */
 180     desc[7] =  30;
 181     desc[8] = 160;
 182
 183     /* max dot clock (1200 MHz) */
 184     desc[9] = 1200 / 10;
 185
 186     /* no extended timing information */
 187     desc[10] = 0x01;
 188
 189     /* padding */
 190     desc[11] = '\n';
 191     memset(desc + 12, ' ', 6);
 192 }
 193
 194 /* additional standard timings 3 */
 195 static void edid_desc_xtra3_std(uint8_t *desc)
 196 {
 197     edid_desc_type(desc, 0xf7);
 198     desc[5] = 10;
 199 }
 200
 201 static void edid_desc_dummy(uint8_t *desc)
 202 {
 203     edid_desc_type(desc, 0x10);
 204 }
 205
 206 static void edid_desc_timing(uint8_t *desc,
 207                              uint32_t xres, uint32_t yres,
 208                              uint32_t xmm, uint32_t ymm)
 209 {
 210     /* pull some realistic looking timings out of thin air */
 211     uint32_t xfront = xres * 25 / 100;
 212     uint32_t xsync  = xres *  3 / 100;
 213     uint32_t xblank = xres * 35 / 100;
 214
 215     uint32_t yfront = yres *  5 / 1000;
 216     uint32_t ysync  = yres *  5 / 1000;
 217     uint32_t yblank = yres * 35 / 1000;
 218
 219     uint32_t clock  = 75 * (xres + xblank) * (yres + yblank);
 220
 221     stl_le_p(desc, clock / 10000);
 222
 223     desc[2] = xres   & 0xff;
 224     desc[3] = xblank & 0xff;
 225     desc[4] = (((xres   & 0xf00) >> 4) |
 226                ((xblank & 0xf00) >> 8));
 227
 228     desc[5] = yres   & 0xff;
 229     desc[6] = yblank & 0xff;
 230     desc[7] = (((yres   & 0xf00) >> 4) |
 231                ((yblank & 0xf00) >> 8));
 232
 233     desc[8] = xfront & 0xff;
 234     desc[9] = xsync  & 0xff;
 235
 236     desc[10] = (((yfront & 0x00f) << 4) |
 237                 ((ysync  & 0x00f) << 0));
 238     desc[11] = (((xfront & 0x300) >> 2) |
 239                 ((xsync  & 0x300) >> 4) |
 240                 ((yfront & 0x030) >> 2) |
 241                 ((ysync  & 0x030) >> 4));
 242
 243     desc[12] = xmm & 0xff;
 244     desc[13] = ymm & 0xff;
 245     desc[14] = (((xmm & 0xf00) >> 4) |
 246                 ((ymm & 0xf00) >> 8));
 247
 248     desc[17] = 0x18;
 249 }
 250
 251 static uint32_t edid_to_10bit(float value)
 252 {
 253     return (uint32_t)(value * 1024 + 0.5);
 254 }
 255
 256 static void edid_colorspace(uint8_t *edid,
 257                             float rx, float ry,
 258                             float gx, float gy,
 259                             float bx, float by,
 260                             float wx, float wy)
 261 {
 262     uint32_t red_x   = edid_to_10bit(rx);
 263     uint32_t red_y   = edid_to_10bit(ry);
 264     uint32_t green_x = edid_to_10bit(gx);
 265     uint32_t green_y = edid_to_10bit(gy);
 266     uint32_t blue_x  = edid_to_10bit(bx);
 267     uint32_t blue_y  = edid_to_10bit(by);
 268     uint32_t white_x = edid_to_10bit(wx);
 269     uint32_t white_y = edid_to_10bit(wy);
 270
 271     edid[25] = (((red_x   & 0x03) << 6) |
 272                 ((red_y   & 0x03) << 4) |
 273                 ((green_x & 0x03) << 2) |
 274                 ((green_y & 0x03) << 0));
 275     edid[26] = (((blue_x  & 0x03) << 6) |
 276                 ((blue_y  & 0x03) << 4) |
 277                 ((white_x & 0x03) << 2) |
 278                 ((white_y & 0x03) << 0));
 279     edid[27] = red_x   >> 2;
 280     edid[28] = red_y   >> 2;
 281     edid[29] = green_x >> 2;
 282     edid[30] = green_y >> 2;
 283     edid[31] = blue_x  >> 2;
 284     edid[32] = blue_y  >> 2;
 285     edid[33] = white_x >> 2;
 286     edid[34] = white_y >> 2;
 287 }
 288
 289 static uint32_t qemu_edid_dpi_from_mm(uint32_t mm, uint32_t res)
 290 {
 291     return res * 254 / 10 / mm;
 292 }
 293
 294 uint32_t qemu_edid_dpi_to_mm(uint32_t dpi, uint32_t res)
 295 {
 296     return res * 254 / 10 / dpi;
 297 }
 298
 299 void qemu_edid_generate(uint8_t *edid, size_t size,
 300                         qemu_edid_info *info)
 301 {
 302     uint32_t desc = 54;
 303     uint8_t *xtra3 = NULL;
 304     uint8_t *dta = NULL;
 305     uint32_t width_mm, height_mm;
 306     uint32_t dpi = 100; /* if no width_mm/height_mm */
 307
 308     /* =============== set defaults  =============== */
 309
 310     if (!info->vendor || strlen(info->vendor) != 3) {
 311         info->vendor = "RHT";
 312     }
 313     if (!info->name) {
 314         info->name = "QEMU Monitor";
 315     }
 316     if (!info->prefx) {
 317         info->prefx = 1024;
 318     }
 319     if (!info->prefy) {
 320         info->prefy = 768;
 321     }
 322     if (info->width_mm && info->height_mm) {
 323         width_mm = info->width_mm;
 324         height_mm = info->height_mm;
 325         dpi = qemu_edid_dpi_from_mm(width_mm, info->prefx);
 326     } else {
 327         width_mm = qemu_edid_dpi_to_mm(dpi, info->prefx);
 328         height_mm = qemu_edid_dpi_to_mm(dpi, info->prefy);
 329     }
 330
 331     /* =============== extensions  =============== */
 332
 333     if (size >= 256) {
 334         dta = edid + 128;
 335         edid[126]++;
 336         edid_ext_dta(dta);
 337     }
 338
 339     /* =============== header information =============== */
 340
 341     /* fixed */
 342     edid[0] = 0x00;
 343     edid[1] = 0xff;
 344     edid[2] = 0xff;
 345     edid[3] = 0xff;
 346     edid[4] = 0xff;
 347     edid[5] = 0xff;
 348     edid[6] = 0xff;
 349     edid[7] = 0x00;
 350
 351     /* manufacturer id, product code, serial number */
 352     uint16_t vendor_id = ((((info->vendor[0] - '@') & 0x1f) << 10) |
 353                           (((info->vendor[1] - '@') & 0x1f) <<  5) |
 354                           (((info->vendor[2] - '@') & 0x1f) <<  0));
 355     uint16_t model_nr = 0x1234;
 356     uint32_t serial_nr = info->serial ? atoi(info->serial) : 0;
 357     stw_be_p(edid +  8, vendor_id);
 358     stw_le_p(edid + 10, model_nr);
 359     stl_le_p(edid + 12, serial_nr);
 360
 361     /* manufacture week and year */
 362     edid[16] = 42;
 363     edid[17] = 2014 - 1990;
 364
 365     /* edid version */
 366     edid[18] = 1;
 367     edid[19] = 4;
 368
 369
 370     /* =============== basic display parameters =============== */
 371
 372     /* video input: digital, 8bpc, displayport */
 373     edid[20] = 0xa5;
 374
 375     /* screen size: undefined */
 376     edid[21] = width_mm / 10;
 377     edid[22] = height_mm / 10;
 378
 379     /* display gamma: 2.2 */
 380     edid[23] = 220 - 100;
 381
 382     /* supported features bitmap: std sRGB, preferred timing */
 383     edid[24] = 0x06;
 384
 385
 386     /* =============== chromaticity coordinates =============== */
 387
 388     /* standard sRGB colorspace */
 389     edid_colorspace(edid,
 390                     0.6400, 0.3300,   /* red   */
 391                     0.3000, 0.6000,   /* green */
 392                     0.1500, 0.0600,   /* blue  */
 393                     0.3127, 0.3290);  /* white point  */
 394
 395     /* =============== established timing bitmap =============== */
 396     /* =============== standard timing information =============== */
 397
 398     /* both filled by edid_fill_modes() */
 399
 400
 401     /* =============== descriptor blocks =============== */
 402
 403     edid_desc_timing(edid + desc, info->prefx, info->prefy,
 404                      width_mm, height_mm);
 405     desc += 18;
 406
 407     edid_desc_ranges(edid + desc);
 408     desc += 18;
 409
 410     if (info->name) {
 411         edid_desc_text(edid + desc, 0xfc, info->name);
 412         desc += 18;
 413     }
 414
 415     if (info->serial) {
 416         edid_desc_text(edid + desc, 0xff, info->serial);
 417         desc += 18;
 418     }
 419
 420     if (desc < 126) {
 421         xtra3 = edid + desc;
 422         edid_desc_xtra3_std(xtra3);
 423         desc += 18;
 424     }
 425
 426     while (desc < 126) {
 427         edid_desc_dummy(edid + desc);
 428         desc += 18;
 429     }
 430
 431     /* =============== finish up =============== */
 432
 433     edid_fill_modes(edid, xtra3, dta, info->maxx, info->maxy);
 434     edid_checksum(edid);
 435     if (dta) {
 436         edid_checksum(dta);
 437     }
 438 }
 439
 440 size_t qemu_edid_size(uint8_t *edid)
 441 {
 442     uint32_t exts;
 443
 444     if (edid[0] != 0x00 ||
 445         edid[1] != 0xff) {
 446         /* doesn't look like a valid edid block */
 447         return 0;
 448     }
 449
 450     exts = edid[126];
 451     return 128 * (exts + 1);
 452 }