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-common.h"
   9 #include "qemu/bswap.h"
  10 #include "hw/display/edid.h"
  11
  12 static const struct edid_mode {
  13     uint32_t xres;
  14     uint32_t yres;
  15     uint32_t byte;
  16     uint32_t xtra3;
  17     uint32_t bit;
  18     uint32_t dta;
  19 } modes[] = {
  20     /* dea/dta extension timings (all @ 50 Hz) */
  21     { .xres = 5120,   .yres = 2160,   .dta = 125 },
  22     { .xres = 4096,   .yres = 2160,   .dta = 101 },
  23     { .xres = 3840,   .yres = 2160,   .dta =  96 },
  24     { .xres = 2560,   .yres = 1080,   .dta =  89 },
  25     { .xres = 2048,   .yres = 1152 },
  26     { .xres = 1920,   .yres = 1080,   .dta =  31 },
  27
  28     /* additional standard timings 3 (all @ 60Hz) */
  29     { .xres = 1920,   .yres = 1440,   .xtra3 = 11,   .bit = 5 },
  30     { .xres = 1920,   .yres = 1200,   .xtra3 = 10,   .bit = 0 },
  31     { .xres = 1856,   .yres = 1392,   .xtra3 = 10,   .bit = 3 },
  32     { .xres = 1792,   .yres = 1344,   .xtra3 = 10,   .bit = 5 },
  33     { .xres = 1600,   .yres = 1200,   .xtra3 =  9,   .bit = 2 },
  34     { .xres = 1680,   .yres = 1050,   .xtra3 =  9,   .bit = 5 },
  35     { .xres = 1440,   .yres = 1050,   .xtra3 =  8,   .bit = 1 },
  36     { .xres = 1440,   .yres =  900,   .xtra3 =  8,   .bit = 5 },
  37     { .xres = 1360,   .yres =  768,   .xtra3 =  8,   .bit = 7 },
  38     { .xres = 1280,   .yres = 1024,   .xtra3 =  7,   .bit = 1 },
  39     { .xres = 1280,   .yres =  960,   .xtra3 =  7,   .bit = 3 },
  40     { .xres = 1280,   .yres =  768,   .xtra3 =  7,   .bit = 6 },
  41
  42     /* established timings (all @ 60Hz) */
  43     { .xres = 1024,   .yres =  768,   .byte  = 36,   .bit = 3 },
  44     { .xres =  800,   .yres =  600,   .byte  = 35,   .bit = 0 },
  45     { .xres =  640,   .yres =  480,   .byte  = 35,   .bit = 5 },
  46 };
  47
  48 static void edid_ext_dta(uint8_t *dta)
  49 {
  50     dta[0] = 0x02;
  51     dta[1] = 0x03;
  52     dta[2] = 0x05;
  53     dta[3] = 0x00;
  54
  55     /* video data block */
  56     dta[4] = 0x40;
  57 }
  58
  59 static void edid_ext_dta_mode(uint8_t *dta, uint8_t nr)
  60 {
  61     dta[dta[2]] = nr;
  62     dta[2]++;
  63     dta[4]++;
  64 }
  65
  66 static int edid_std_mode(uint8_t *mode, uint32_t xres, uint32_t yres)
  67 {
  68     uint32_t aspect;
  69
  70     if (xres == 0 || yres == 0) {
  71         mode[0] = 0x01;
  72         mode[1] = 0x01;
  73         return 0;
  74
  75     } else if (xres * 10 == yres * 16) {
  76         aspect = 0;
  77     } else if (xres * 3 == yres * 4) {
  78         aspect = 1;
  79     } else if (xres * 4 == yres * 5) {
  80         aspect = 2;
  81     } else if (xres * 9 == yres * 16) {
  82         aspect = 3;
  83     } else {
  84         return -1;
  85     }
  86
  87     if ((xres / 8) - 31 > 255) {
  88         return -1;
  89     }
  90
  91     mode[0] = (xres / 8) - 31;
  92     mode[1] = ((aspect << 6) | (60 - 60));
  93     return 0;
  94 }
  95
  96 static void edid_fill_modes(uint8_t *edid, uint8_t *xtra3, uint8_t *dta,
  97                             uint32_t maxx, uint32_t maxy)
  98 {
  99     const struct edid_mode *mode;
 100     int std = 38;
 101     int rc, i;
 102
 103     for (i = 0; i < ARRAY_SIZE(modes); i++) {
 104         mode = modes + i;
 105
 106         if ((maxx && mode->xres > maxx) ||
 107             (maxy && mode->yres > maxy)) {
 108             continue;
 109         }
 110
 111         if (mode->byte) {
 112             edid[mode->byte] |= (1 << mode->bit);
 113         } else if (mode->xtra3 && xtra3) {
 114             xtra3[mode->xtra3] |= (1 << mode->bit);
 115         } else if (std < 54) {
 116             rc = edid_std_mode(edid + std, mode->xres, mode->yres);
 117             if (rc == 0) {
 118                 std += 2;
 119             }
 120         }
 121
 122         if (dta && mode->dta) {
 123             edid_ext_dta_mode(dta, mode->dta);
 124         }
 125     }
 126
 127     while (std < 54) {
 128         edid_std_mode(edid + std, 0, 0);
 129         std += 2;
 130     }
 131 }
 132
 133 static void edid_checksum(uint8_t *edid)
 134 {
 135     uint32_t sum = 0;
 136     int i;
 137
 138     for (i = 0; i < 127; i++) {
 139         sum += edid[i];
 140     }
 141     sum &= 0xff;
 142     if (sum) {
 143         edid[127] = 0x100 - sum;
 144     }
 145 }
 146
 147 static void edid_desc_type(uint8_t *desc, uint8_t type)
 148 {
 149     desc[0] = 0;
 150     desc[1] = 0;
 151     desc[2] = 0;
 152     desc[3] = type;
 153     desc[4] = 0;
 154 }
 155
 156 static void edid_desc_text(uint8_t *desc, uint8_t type,
 157                            const char *text)
 158 {
 159     size_t len;
 160
 161     edid_desc_type(desc, type);
 162     memset(desc + 5, ' ', 13);
 163
 164     len = strlen(text);
 165     if (len > 12) {
 166         len = 12;
 167     }
 168     strncpy((char *)(desc + 5), text, len);
 169     desc[5 + len] = '\n';
 170 }
 171
 172 static void edid_desc_ranges(uint8_t *desc)
 173 {
 174     edid_desc_type(desc, 0xfd);
 175
 176     /* vertical (50 -> 125 Hz) */
 177     desc[5] =  50;
 178     desc[6] = 125;
 179
 180     /* horizontal (30 -> 160 kHz) */
 181     desc[7] =  30;
 182     desc[8] = 160;
 183
 184     /* max dot clock (1200 MHz) */
 185     desc[9] = 1200 / 10;
 186
 187     /* no extended timing information */
 188     desc[10] = 0x01;
 189
 190     /* padding */
 191     desc[11] = '\n';
 192     memset(desc + 12, ' ', 6);
 193 }
 194
 195 /* additional standard timings 3 */
 196 static void edid_desc_xtra3_std(uint8_t *desc)
 197 {
 198     edid_desc_type(desc, 0xf7);
 199     desc[5] = 10;
 200 }
 201
 202 static void edid_desc_dummy(uint8_t *desc)
 203 {
 204     edid_desc_type(desc, 0x10);
 205 }
 206
 207 static void edid_desc_timing(uint8_t *desc,
 208                              uint32_t xres, uint32_t yres,
 209                              uint32_t dpi)
 210 {
 211     /* physical display size */
 212     uint32_t xmm = xres * dpi / 254;
 213     uint32_t ymm = yres * dpi / 254;
 214
 215     /* pull some realistic looking timings out of thin air */
 216     uint32_t xfront = xres * 25 / 100;
 217     uint32_t xsync  = xres *  3 / 100;
 218     uint32_t xblank = xres * 35 / 100;
 219
 220     uint32_t yfront = yres *  5 / 1000;
 221     uint32_t ysync  = yres *  5 / 1000;
 222     uint32_t yblank = yres * 35 / 1000;
 223
 224     uint32_t clock  = 75 * (xres + xblank) * (yres + yblank);
 225
 226     *(uint32_t *)(desc) = cpu_to_le32(clock / 10000);
 227
 228     desc[2] = xres   & 0xff;
 229     desc[3] = xblank & 0xff;
 230     desc[4] = (((xres   & 0xf00) >> 4) |
 231                ((xblank & 0xf00) >> 8));
 232
 233     desc[5] = yres   & 0xff;
 234     desc[6] = yblank & 0xff;
 235     desc[7] = (((yres   & 0xf00) >> 4) |
 236                ((yblank & 0xf00) >> 8));
 237
 238     desc[8] = xfront & 0xff;
 239     desc[9] = xsync  & 0xff;
 240
 241     desc[10] = (((yfront & 0x00f) << 4) |
 242                 ((ysync  & 0x00f) << 0));
 243     desc[11] = (((xfront & 0x300) >> 2) |
 244                 ((xsync  & 0x300) >> 4) |
 245                 ((yfront & 0x030) >> 2) |
 246                 ((ysync  & 0x030) >> 4));
 247
 248     desc[12] = xmm & 0xff;
 249     desc[13] = ymm & 0xff;
 250     desc[14] = (((xmm & 0xf00) >> 4) |
 251                 ((ymm & 0xf00) >> 8));
 252
 253     desc[17] = 0x18;
 254 }
 255
 256 static uint32_t edid_to_10bit(float value)
 257 {
 258     return (uint32_t)(value * 1024 + 0.5);
 259 }
 260
 261 static void edid_colorspace(uint8_t *edid,
 262                             float rx, float ry,
 263                             float gx, float gy,
 264                             float bx, float by,
 265                             float wx, float wy)
 266 {
 267     uint32_t red_x   = edid_to_10bit(rx);
 268     uint32_t red_y   = edid_to_10bit(ry);
 269     uint32_t green_x = edid_to_10bit(gx);
 270     uint32_t green_y = edid_to_10bit(gy);
 271     uint32_t blue_x  = edid_to_10bit(bx);
 272     uint32_t blue_y  = edid_to_10bit(by);
 273     uint32_t white_x = edid_to_10bit(wx);
 274     uint32_t white_y = edid_to_10bit(wy);
 275
 276     edid[25] = (((red_x   & 0x03) << 6) |
 277                 ((red_y   & 0x03) << 4) |
 278                 ((green_x & 0x03) << 2) |
 279                 ((green_y & 0x03) << 0));
 280     edid[26] = (((blue_x  & 0x03) << 6) |
 281                 ((blue_y  & 0x03) << 4) |
 282                 ((white_x & 0x03) << 2) |
 283                 ((white_y & 0x03) << 0));
 284     edid[27] = red_x   >> 2;
 285     edid[28] = red_y   >> 2;
 286     edid[29] = green_x >> 2;
 287     edid[30] = green_y >> 2;
 288     edid[31] = blue_x  >> 2;
 289     edid[32] = blue_y  >> 2;
 290     edid[33] = white_x >> 2;
 291     edid[34] = white_y >> 2;
 292 }
 293
 294 void qemu_edid_generate(uint8_t *edid, size_t size,
 295                         qemu_edid_info *info)
 296 {
 297     uint32_t desc = 54;
 298     uint8_t *xtra3 = NULL;
 299     uint8_t *dta = NULL;
 300
 301     /* =============== set defaults  =============== */
 302
 303     if (!info->vendor || strlen(info->vendor) != 3) {
 304         info->vendor = "EMU";
 305     }
 306     if (!info->name) {
 307         info->name = "QEMU Monitor";
 308     }
 309     if (!info->dpi) {
 310         info->dpi = 100;
 311     }
 312     if (!info->prefx) {
 313         info->prefx = 1024;
 314     }
 315     if (!info->prefy) {
 316         info->prefy = 768;
 317     }
 318
 319     /* =============== extensions  =============== */
 320
 321     if (size >= 256) {
 322         dta = edid + 128;
 323         edid[126]++;
 324         edid_ext_dta(dta);
 325     }
 326
 327     /* =============== header information =============== */
 328
 329     /* fixed */
 330     edid[0] = 0x00;
 331     edid[1] = 0xff;
 332     edid[2] = 0xff;
 333     edid[3] = 0xff;
 334     edid[4] = 0xff;
 335     edid[5] = 0xff;
 336     edid[6] = 0xff;
 337     edid[7] = 0x00;
 338
 339     /* manufacturer id, product code, serial number */
 340     uint16_t vendor_id = ((((info->vendor[0] - '@') & 0x1f) << 10) |
 341                           (((info->vendor[1] - '@') & 0x1f) <<  5) |
 342                           (((info->vendor[2] - '@') & 0x1f) <<  0));
 343     uint16_t model_nr = 0x1234;
 344     uint32_t serial_nr = info->serial ? atoi(info->serial) : 0;
 345     *(uint16_t *)(edid +  8) = cpu_to_be16(vendor_id);
 346     *(uint16_t *)(edid + 10) = cpu_to_le16(model_nr);
 347     *(uint32_t *)(edid + 12) = cpu_to_le32(serial_nr);
 348
 349     /* manufacture week and year */
 350     edid[16] = 42;
 351     edid[17] = 2014 - 1990;
 352
 353     /* edid version */
 354     edid[18] = 1;
 355     edid[19] = 4;
 356
 357
 358     /* =============== basic display parameters =============== */
 359
 360     /* video input: digital, 8bpc, displayport */
 361     edid[20] = 0xa5;
 362
 363     /* screen size: undefined */
 364     edid[21] = info->prefx * info->dpi / 2540;
 365     edid[22] = info->prefy * info->dpi / 2540;
 366
 367     /* display gamma: 2.2 */
 368     edid[23] = 220 - 100;
 369
 370     /* supported features bitmap: std sRGB, preferred timing */
 371     edid[24] = 0x06;
 372
 373
 374     /* =============== chromaticity coordinates =============== */
 375
 376     /* standard sRGB colorspace */
 377     edid_colorspace(edid,
 378                     0.6400, 0.3300,   /* red   */
 379                     0.3000, 0.6000,   /* green */
 380                     0.1500, 0.0600,   /* blue  */
 381                     0.3127, 0.3290);  /* white point  */
 382
 383     /* =============== established timing bitmap =============== */
 384     /* =============== standard timing information =============== */
 385
 386     /* both filled by edid_fill_modes() */
 387
 388
 389     /* =============== descriptor blocks =============== */
 390
 391     edid_desc_timing(edid + desc, info->prefx, info->prefy, info->dpi);
 392     desc += 18;
 393
 394     edid_desc_ranges(edid + desc);
 395     desc += 18;
 396
 397     if (info->name) {
 398         edid_desc_text(edid + desc, 0xfc, info->name);
 399         desc += 18;
 400     }
 401
 402     if (info->serial) {
 403         edid_desc_text(edid + desc, 0xff, info->serial);
 404         desc += 18;
 405     }
 406
 407     if (desc < 126) {
 408         xtra3 = edid + desc;
 409         edid_desc_xtra3_std(xtra3);
 410         desc += 18;
 411     }
 412
 413     while (desc < 126) {
 414         edid_desc_dummy(edid + desc);
 415         desc += 18;
 416     }
 417
 418     /* =============== finish up =============== */
 419
 420     edid_fill_modes(edid, xtra3, dta, info->maxx, info->maxy);
 421     edid_checksum(edid);
 422     if (dta) {
 423         edid_checksum(dta);
 424     }
 425 }
 426
 427 size_t qemu_edid_size(uint8_t *edid)
 428 {
 429     uint32_t exts;
 430
 431     if (edid[0] != 0x00 ||
 432         edid[1] != 0xff) {
 433         /* doesn't look like a valid edid block */
 434         return 0;
 435     }
 436
 437     exts = edid[126];
 438     return 128 * (exts + 1);
 439 }