drivers/video/kyro/STG4000OverlayDevice.c

   1 /*
   2  *  linux/drivers/video/kyro/STG4000OverlayDevice.c
   3  *
   4  *  Copyright (C) 2000 Imagination Technologies Ltd
   5  *  Copyright (C) 2002 STMicroelectronics
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License.  See the file COPYING in the main directory of this archive
   9  * for more details.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/types.h>
  15
  16 #include "STG4000Reg.h"
  17
  18 /* HW Defines */
  19
  20 #define STG4000_NO_SCALING    0x800
  21 #define STG4000_NO_DECIMATION 0xFFFFFFFF
  22
  23 /* Primary surface */
  24 #define STG4000_PRIM_NUM_PIX   5
  25 #define STG4000_PRIM_ALIGN     4
  26 #define STG4000_PRIM_ADDR_BITS 20
  27
  28 #define STG4000_PRIM_MIN_WIDTH  640
  29 #define STG4000_PRIM_MAX_WIDTH  1600
  30 #define STG4000_PRIM_MIN_HEIGHT 480
  31 #define STG4000_PRIM_MAX_HEIGHT 1200
  32
  33 /* Overlay surface */
  34 #define STG4000_OVRL_NUM_PIX   4
  35 #define STG4000_OVRL_ALIGN     2
  36 #define STG4000_OVRL_ADDR_BITS 20
  37 #define STG4000_OVRL_NUM_MODES 5
  38
  39 #define STG4000_OVRL_MIN_WIDTH  0
  40 #define STG4000_OVRL_MAX_WIDTH  720
  41 #define STG4000_OVRL_MIN_HEIGHT 0
  42 #define STG4000_OVRL_MAX_HEIGHT 576
  43
  44 /* Decimation and Scaling */
  45 static u32 adwDecim8[33] = {
  46             0xffffffff, 0xfffeffff, 0xffdffbff, 0xfefefeff, 0xfdf7efbf,
  47             0xfbdf7bdf, 0xf7bbddef, 0xeeeeeeef, 0xeeddbb77, 0xedb76db7,
  48             0xdb6db6db, 0xdb5b5b5b, 0xdab5ad6b, 0xd5ab55ab, 0xd555aaab,
  49             0xaaaaaaab, 0xaaaa5555, 0xaa952a55, 0xa94a5295, 0xa5252525,
  50             0xa4924925, 0x92491249, 0x91224489, 0x91111111, 0x90884211,
  51             0x88410821, 0x88102041, 0x81010101, 0x80800801, 0x80010001,
  52             0x80000001, 0x00000001, 0x00000000
  53 };
  54
  55 typedef struct _OVRL_SRC_DEST {
  56         /*clipped on-screen pixel position of overlay */
  57         u32 ulDstX1;
  58         u32 ulDstY1;
  59         u32 ulDstX2;
  60         u32 ulDstY2;
  61
  62         /*clipped pixel pos of source data within buffer thses need to be 128 bit word aligned */
  63         u32 ulSrcX1;
  64         u32 ulSrcY1;
  65         u32 ulSrcX2;
  66         u32 ulSrcY2;
  67
  68         /* on-screen pixel position of overlay */
  69         s32 lDstX1;
  70         s32 lDstY1;
  71         s32 lDstX2;
  72         s32 lDstY2;
  73 } OVRL_SRC_DEST;
  74
  75 static u32 ovlWidth, ovlHeight, ovlStride;
  76 static int ovlLinear;
  77
  78 void ResetOverlayRegisters(volatile STG4000REG __iomem *pSTGReg)
  79 {
  80         u32 tmp;
  81
  82         /* Set Overlay address to default */
  83         tmp = STG_READ_REG(DACOverlayAddr);
  84         CLEAR_BITS_FRM_TO(0, 20);
  85         CLEAR_BIT(31);
  86         STG_WRITE_REG(DACOverlayAddr, tmp);
  87
  88         /* Set Overlay U address */
  89         tmp = STG_READ_REG(DACOverlayUAddr);
  90         CLEAR_BITS_FRM_TO(0, 20);
  91         STG_WRITE_REG(DACOverlayUAddr, tmp);
  92
  93         /* Set Overlay V address */
  94         tmp = STG_READ_REG(DACOverlayVAddr);
  95         CLEAR_BITS_FRM_TO(0, 20);
  96         STG_WRITE_REG(DACOverlayVAddr, tmp);
  97
  98         /* Set Overlay Size */
  99         tmp = STG_READ_REG(DACOverlaySize);
 100         CLEAR_BITS_FRM_TO(0, 10);
 101         CLEAR_BITS_FRM_TO(12, 31);
 102         STG_WRITE_REG(DACOverlaySize, tmp);
 103
 104         /* Set Overlay Vt Decimation */
 105         tmp = STG4000_NO_DECIMATION;
 106         STG_WRITE_REG(DACOverlayVtDec, tmp);
 107
 108         /* Set Overlay format to default value */
 109         tmp = STG_READ_REG(DACPixelFormat);
 110         CLEAR_BITS_FRM_TO(4, 7);
 111         CLEAR_BITS_FRM_TO(16, 22);
 112         STG_WRITE_REG(DACPixelFormat, tmp);
 113
 114         /* Set Vertical scaling to default */
 115         tmp = STG_READ_REG(DACVerticalScal);
 116         CLEAR_BITS_FRM_TO(0, 11);
 117         CLEAR_BITS_FRM_TO(16, 22);
 118         tmp |= STG4000_NO_SCALING;      /* Set to no scaling */
 119         STG_WRITE_REG(DACVerticalScal, tmp);
 120
 121         /* Set Horizontal Scaling to default */
 122         tmp = STG_READ_REG(DACHorizontalScal);
 123         CLEAR_BITS_FRM_TO(0, 11);
 124         CLEAR_BITS_FRM_TO(16, 17);
 125         tmp |= STG4000_NO_SCALING;      /* Set to no scaling */
 126         STG_WRITE_REG(DACHorizontalScal, tmp);
 127
 128         /* Set Blend mode to Alpha Blend */
 129         /* ????? SG 08/11/2001 Surely this isn't the alpha blend mode,
 130            hopefully its overwrite
 131          */
 132         tmp = STG_READ_REG(DACBlendCtrl);
 133         CLEAR_BITS_FRM_TO(0, 30);
 134         tmp = (GRAPHICS_MODE << 28);
 135         STG_WRITE_REG(DACBlendCtrl, tmp);
 136
 137 }
 138
 139 int CreateOverlaySurface(volatile STG4000REG __iomem *pSTGReg,
 140                          u32 inWidth,
 141                          u32 inHeight,
 142                          int bLinear,
 143                          u32 ulOverlayOffset,
 144                          u32 * retStride, u32 * retUVStride)
 145 {
 146         u32 tmp;
 147         u32 ulStride;
 148
 149         if (inWidth > STG4000_OVRL_MAX_WIDTH ||
 150             inHeight > STG4000_OVRL_MAX_HEIGHT) {
 151                 return -EINVAL;
 152         }
 153
 154         /* Stride in 16 byte words - 16Bpp */
 155         if (bLinear) {
 156                 /* Format is 16bits so num 16 byte words is width/8 */
 157                 if ((inWidth & 0x7) == 0) {     /* inWidth % 8 */
 158                         ulStride = (inWidth / 8);
 159                 } else {
 160                         /* Round up to next 16byte boundary */
 161                         ulStride = ((inWidth + 8) / 8);
 162                 }
 163         } else {
 164                 /* Y component is 8bits so num 16 byte words is width/16 */
 165                 if ((inWidth & 0xf) == 0) {     /* inWidth % 16 */
 166                         ulStride = (inWidth / 16);
 167                 } else {
 168                         /* Round up to next 16byte boundary */
 169                         ulStride = ((inWidth + 16) / 16);
 170                 }
 171         }
 172
 173
 174         /* Set Overlay address and Format mode */
 175         tmp = STG_READ_REG(DACOverlayAddr);
 176         CLEAR_BITS_FRM_TO(0, 20);
 177         if (bLinear) {
 178                 CLEAR_BIT(31);  /* Overlay format to Linear */
 179         } else {
 180                 tmp |= SET_BIT(31);     /* Overlay format to Planer */
 181         }
 182
 183         /* Only bits 24:4 of the Overlay address */
 184         tmp |= (ulOverlayOffset >> 4);
 185         STG_WRITE_REG(DACOverlayAddr, tmp);
 186
 187         if (!bLinear) {
 188                 u32 uvSize =
 189                     (inWidth & 0x1) ? (inWidth + 1 / 2) : (inWidth / 2);
 190                 u32 uvStride;
 191                 u32 ulOffset;
 192                 /* Y component is 8bits so num 32 byte words is width/32 */
 193                 if ((uvSize & 0xf) == 0) {      /* inWidth % 16 */
 194                         uvStride = (uvSize / 16);
 195                 } else {
 196                         /* Round up to next 32byte boundary */
 197                         uvStride = ((uvSize + 16) / 16);
 198                 }
 199
 200                 ulOffset = ulOverlayOffset + (inHeight * (ulStride * 16));
 201                 /* Align U,V data to 32byte boundary */
 202                 if ((ulOffset & 0x1f) != 0)
 203                         ulOffset = (ulOffset + 32L) & 0xffffffE0L;
 204
 205                 tmp = STG_READ_REG(DACOverlayUAddr);
 206                 CLEAR_BITS_FRM_TO(0, 20);
 207                 tmp |= (ulOffset >> 4);
 208                 STG_WRITE_REG(DACOverlayUAddr, tmp);
 209
 210                 ulOffset += (inHeight / 2) * (uvStride * 16);
 211                 /* Align U,V data to 32byte boundary */
 212                 if ((ulOffset & 0x1f) != 0)
 213                         ulOffset = (ulOffset + 32L) & 0xffffffE0L;
 214
 215                 tmp = STG_READ_REG(DACOverlayVAddr);
 216                 CLEAR_BITS_FRM_TO(0, 20);
 217                 tmp |= (ulOffset >> 4);
 218                 STG_WRITE_REG(DACOverlayVAddr, tmp);
 219
 220                 *retUVStride = uvStride * 16;
 221         }
 222
 223
 224         /* Set Overlay YUV pixel format
 225          * Make sure that LUT not used - ??????
 226          */
 227         tmp = STG_READ_REG(DACPixelFormat);
 228         /* Only support Planer or UYVY linear formats */
 229         CLEAR_BITS_FRM_TO(4, 9);
 230         STG_WRITE_REG(DACPixelFormat, tmp);
 231
 232         ovlWidth = inWidth;
 233         ovlHeight = inHeight;
 234         ovlStride = ulStride;
 235         ovlLinear = bLinear;
 236         *retStride = ulStride << 4;     /* In bytes */
 237
 238         return 0;
 239 }
 240
 241 int SetOverlayBlendMode(volatile STG4000REG __iomem *pSTGReg,
 242                         OVRL_BLEND_MODE mode,
 243                         u32 ulAlpha, u32 ulColorKey)
 244 {
 245         u32 tmp;
 246
 247         tmp = STG_READ_REG(DACBlendCtrl);
 248         CLEAR_BITS_FRM_TO(28, 30);
 249         tmp |= (mode << 28);
 250
 251         switch (mode) {
 252         case COLOR_KEY:
 253                 CLEAR_BITS_FRM_TO(0, 23);
 254                 tmp |= (ulColorKey & 0x00FFFFFF);
 255                 break;
 256
 257         case GLOBAL_ALPHA:
 258                 CLEAR_BITS_FRM_TO(24, 27);
 259                 tmp |= ((ulAlpha & 0xF) << 24);
 260                 break;
 261
 262         case CK_PIXEL_ALPHA:
 263                 CLEAR_BITS_FRM_TO(0, 23);
 264                 tmp |= (ulColorKey & 0x00FFFFFF);
 265                 break;
 266
 267         case CK_GLOBAL_ALPHA:
 268                 CLEAR_BITS_FRM_TO(0, 23);
 269                 tmp |= (ulColorKey & 0x00FFFFFF);
 270                 CLEAR_BITS_FRM_TO(24, 27);
 271                 tmp |= ((ulAlpha & 0xF) << 24);
 272                 break;
 273
 274         case GRAPHICS_MODE:
 275         case PER_PIXEL_ALPHA:
 276                 break;
 277
 278         default:
 279                 return -EINVAL;
 280         }
 281
 282         STG_WRITE_REG(DACBlendCtrl, tmp);
 283
 284         return 0;
 285 }
 286
 287 void EnableOverlayPlane(volatile STG4000REG __iomem *pSTGReg)
 288 {
 289         u32 tmp;
 290         /* Enable Overlay */
 291         tmp = STG_READ_REG(DACPixelFormat);
 292         tmp |= SET_BIT(7);
 293         STG_WRITE_REG(DACPixelFormat, tmp);
 294
 295         /* Set video stream control */
 296         tmp = STG_READ_REG(DACStreamCtrl);
 297         tmp |= SET_BIT(1);      /* video stream */
 298         STG_WRITE_REG(DACStreamCtrl, tmp);
 299 }
 300
 301 static u32 Overlap(u32 ulBits, u32 ulPattern)
 302 {
 303         u32 ulCount = 0;
 304
 305         while (ulBits) {
 306                 if (!(ulPattern & 1))
 307                         ulCount++;
 308                 ulBits--;
 309                 ulPattern = ulPattern >> 1;
 310         }
 311
 312         return ulCount;
 313
 314 }
 315
 316 int SetOverlayViewPort(volatile STG4000REG __iomem *pSTGReg,
 317                        u32 left, u32 top,
 318                        u32 right, u32 bottom)
 319 {
 320         OVRL_SRC_DEST srcDest;
 321
 322         u32 ulSrcTop, ulSrcBottom;
 323         u32 ulSrc, ulDest;
 324         u32 ulFxScale, ulFxOffset;
 325         u32 ulHeight, ulWidth;
 326         u32 ulPattern;
 327         u32 ulDecimate, ulDecimated;
 328         u32 ulApplied;
 329         u32 ulDacXScale, ulDacYScale;
 330         u32 ulScale;
 331         u32 ulLeft, ulRight;
 332         u32 ulSrcLeft, ulSrcRight;
 333         u32 ulScaleLeft, ulScaleRight;
 334         u32 ulhDecim;
 335         u32 ulsVal;
 336         u32 ulVertDecFactor;
 337         int bResult;
 338         u32 ulClipOff = 0;
 339         u32 ulBits = 0;
 340         u32 ulsAdd = 0;
 341         u32 tmp, ulStride;
 342         u32 ulExcessPixels, ulClip, ulExtraLines;
 343
 344
 345         srcDest.ulSrcX1 = 0;
 346         srcDest.ulSrcY1 = 0;
 347         srcDest.ulSrcX2 = ovlWidth - 1;
 348         srcDest.ulSrcY2 = ovlHeight - 1;
 349
 350         srcDest.ulDstX1 = left;
 351         srcDest.ulDstY1 = top;
 352         srcDest.ulDstX2 = right;
 353         srcDest.ulDstY2 = bottom;
 354
 355         srcDest.lDstX1 = srcDest.ulDstX1;
 356         srcDest.lDstY1 = srcDest.ulDstY1;
 357         srcDest.lDstX2 = srcDest.ulDstX2;
 358         srcDest.lDstY2 = srcDest.ulDstY2;
 359
 360     /************* Vertical decimation/scaling ******************/
 361
 362         /* Get Src Top and Bottom */
 363         ulSrcTop = srcDest.ulSrcY1;
 364         ulSrcBottom = srcDest.ulSrcY2;
 365
 366         ulSrc = ulSrcBottom - ulSrcTop;
 367         ulDest = srcDest.lDstY2 - srcDest.lDstY1;       /* on-screen overlay */
 368
 369         if (ulSrc <= 1)
 370                 return -EINVAL;
 371
 372         /* First work out the position we are to display as offset from the
 373          * source of the buffer
 374          */
 375         ulFxScale = (ulDest << 11) / ulSrc;     /* fixed point scale factor */
 376         ulFxOffset = (srcDest.lDstY2 - srcDest.ulDstY2) << 11;
 377
 378         ulSrcBottom = ulSrcBottom - (ulFxOffset / ulFxScale);
 379         ulSrc = ulSrcBottom - ulSrcTop;
 380         ulHeight = ulSrc;
 381
 382         ulDest = srcDest.ulDstY2 - (srcDest.ulDstY1 - 1);
 383         ulPattern = adwDecim8[ulBits];
 384
 385         /* At this point ulSrc represents the input decimator */
 386         if (ulSrc > ulDest) {
 387                 ulDecimate = ulSrc - ulDest;
 388                 ulBits = 0;
 389                 ulApplied = ulSrc / 32;
 390
 391                 while (((ulBits * ulApplied) +
 392                         Overlap((ulSrc % 32),
 393                                 adwDecim8[ulBits])) < ulDecimate)
 394                         ulBits++;
 395
 396                 ulPattern = adwDecim8[ulBits];
 397                 ulDecimated =
 398                     (ulBits * ulApplied) + Overlap((ulSrc % 32),
 399                                                    ulPattern);
 400                 ulSrc = ulSrc - ulDecimated;    /* the number number of lines that will go into the scaler */
 401         }
 402
 403         if (ulBits && (ulBits != 32)) {
 404                 ulVertDecFactor = (63 - ulBits) / (32 - ulBits);        /* vertical decimation factor scaled up to nearest integer */
 405         } else {
 406                 ulVertDecFactor = 1;
 407         }
 408
 409         ulDacYScale = ((ulSrc - 1) * 2048) / (ulDest + 1);
 410
 411         tmp = STG_READ_REG(DACOverlayVtDec);    /* Decimation */
 412         CLEAR_BITS_FRM_TO(0, 31);
 413         tmp = ulPattern;
 414         STG_WRITE_REG(DACOverlayVtDec, tmp);
 415
 416         /***************** Horizontal decimation/scaling ***************************/
 417
 418         /*
 419          * Now we handle the horizontal case, this is a simplified verison of
 420          * the vertical case in that we decimate by factors of 2.  as we are
 421          * working in words we should always be able to decimate by these
 422          * factors.  as we always have to have a buffer which is aligned to a
 423          * whole number of 128 bit words, we must align the left side to the
 424          * lowest to the next lowest 128 bit boundary, and the right hand edge
 425          * to the next largets boundary, (in a similar way to how we didi it in
 426          * PMX1) as the left and right hand edges are aligned to these
 427          * boundaries normally this only becomes an issue when we are chopping
 428          * of one of the sides We shall work out vertical stuff first
 429          */
 430         ulSrc = srcDest.ulSrcX2 - srcDest.ulSrcX1;
 431         ulDest = srcDest.lDstX2 - srcDest.lDstX1;
 432 #ifdef _OLDCODE
 433         ulLeft = srcDest.ulDstX1;
 434         ulRight = srcDest.ulDstX2;
 435 #else
 436         if (srcDest.ulDstX1 > 2) {
 437                 ulLeft = srcDest.ulDstX1 + 2;
 438                 ulRight = srcDest.ulDstX2 + 1;
 439         } else {
 440                 ulLeft = srcDest.ulDstX1;
 441                 ulRight = srcDest.ulDstX2 + 1;
 442         }
 443 #endif
 444         /* first work out the position we are to display as offset from the source of the buffer */
 445         bResult = 1;
 446
 447         do {
 448                 if (ulDest == 0)
 449                         return -EINVAL;
 450
 451                 /* source pixels per dest pixel <<11 */
 452                 ulFxScale = ((ulSrc - 1) << 11) / (ulDest);
 453
 454                 /* then number of destination pixels out we are */
 455                 ulFxOffset = ulFxScale * ((srcDest.ulDstX1 - srcDest.lDstX1) + ulClipOff);
 456                 ulFxOffset >>= 11;
 457
 458                 /* this replaces the code which was making a decision as to use either ulFxOffset or ulSrcX1 */
 459                 ulSrcLeft = srcDest.ulSrcX1 + ulFxOffset;
 460
 461                 /* then number of destination pixels out we are */
 462                 ulFxOffset = ulFxScale * (srcDest.lDstX2 - srcDest.ulDstX2);
 463                 ulFxOffset >>= 11;
 464
 465                 ulSrcRight = srcDest.ulSrcX2 - ulFxOffset;
 466
 467                 /*
 468                  * we must align these to our 128 bit boundaries. we shall
 469                  * round down the pixel pos to the nearest 8 pixels.
 470                  */
 471                 ulScaleLeft = ulSrcLeft;
 472                 ulScaleRight = ulSrcRight;
 473
 474                 /* shift fxscale until it is in the range of the scaler */
 475                 ulhDecim = 0;
 476                 ulScale = (((ulSrcRight - ulSrcLeft) - 1) << (11 - ulhDecim)) / (ulRight - ulLeft + 2);
 477
 478                 while (ulScale > 0x800) {
 479                         ulhDecim++;
 480                         ulScale = (((ulSrcRight - ulSrcLeft) - 1) << (11 - ulhDecim)) / (ulRight - ulLeft + 2);
 481                 }
 482
 483                 /*
 484                  * to try and get the best values We first try and use
 485                  * src/dwdest for the scale factor, then we move onto src-1
 486                  *
 487                  * we want to check to see if we will need to clip data, if so
 488                  * then we should clip our source so that we don't need to
 489                  */
 490                 if (!ovlLinear) {
 491                         ulSrcLeft &= ~0x1f;
 492
 493                         /*
 494                          * we must align the right hand edge to the next 32
 495                          * pixel` boundary, must be on a 256 boundary so u, and
 496                          * v are 128 bit aligned
 497                          */
 498                         ulSrcRight = (ulSrcRight + 0x1f) & ~0x1f;
 499                 } else {
 500                         ulSrcLeft &= ~0x7;
 501
 502                         /*
 503                          * we must align the right hand edge to the next
 504                          * 8pixel` boundary
 505                          */
 506                         ulSrcRight = (ulSrcRight + 0x7) & ~0x7;
 507                 }
 508
 509                 /* this is the input size line store needs to cope with */
 510                 ulWidth = ulSrcRight - ulSrcLeft;
 511
 512                 /*
 513                  * use unclipped value to work out scale factror this is the
 514                  * scale factor we want we shall now work out the horizonal
 515                  * decimation and scaling
 516                  */
 517                 ulsVal = ((ulWidth / 8) >> ulhDecim);
 518
 519                 if ((ulWidth != (ulsVal << ulhDecim) * 8))
 520                         ulsAdd = 1;
 521
 522                 /* input pixels to scaler; */
 523                 ulSrc = ulWidth >> ulhDecim;
 524
 525                 if (ulSrc <= 2)
 526                         return -EINVAL;
 527
 528                 ulExcessPixels = ((((ulScaleLeft - ulSrcLeft)) << (11 - ulhDecim)) / ulScale);
 529
 530                 ulClip = (ulSrc << 11) / ulScale;
 531                 ulClip -= (ulRight - ulLeft);
 532                 ulClip += ulExcessPixels;
 533
 534                 if (ulClip)
 535                         ulClip--;
 536
 537                 /* We may need to do more here if we really have a HW rev < 5 */
 538         } while (!bResult);
 539
 540         ulExtraLines = (1 << ulhDecim) * ulVertDecFactor;
 541         ulExtraLines += 64;
 542         ulHeight += ulExtraLines;
 543
 544         ulDacXScale = ulScale;
 545
 546
 547         tmp = STG_READ_REG(DACVerticalScal);
 548         CLEAR_BITS_FRM_TO(0, 11);
 549         CLEAR_BITS_FRM_TO(16, 22);      /* Vertical Scaling */
 550
 551         /* Calculate new output line stride, this is always the number of 422
 552            words in the line buffer, so it doesn't matter if the
 553            mode is 420. Then set the vertical scale register.
 554          */
 555         ulStride = (ulWidth >> (ulhDecim + 3)) + ulsAdd;
 556         tmp |= ((ulStride << 16) | (ulDacYScale));      /* DAC_LS_CTRL = stride */
 557         STG_WRITE_REG(DACVerticalScal, tmp);
 558
 559         /* Now set up the overlay size using the modified width and height
 560            from decimate and scaling calculations
 561          */
 562         tmp = STG_READ_REG(DACOverlaySize);
 563         CLEAR_BITS_FRM_TO(0, 10);
 564         CLEAR_BITS_FRM_TO(12, 31);
 565
 566         if (ovlLinear) {
 567                 tmp |=
 568                     (ovlStride | ((ulHeight + 1) << 12) |
 569                      (((ulWidth / 8) - 1) << 23));
 570         } else {
 571                 tmp |=
 572                     (ovlStride | ((ulHeight + 1) << 12) |
 573                      (((ulWidth / 32) - 1) << 23));
 574         }
 575
 576         STG_WRITE_REG(DACOverlaySize, tmp);
 577
 578         /* Set Video Window Start */
 579         tmp = ((ulLeft << 16)) | (srcDest.ulDstY1);
 580         STG_WRITE_REG(DACVidWinStart, tmp);
 581
 582         /* Set Video Window End */
 583         tmp = ((ulRight) << 16) | (srcDest.ulDstY2);
 584         STG_WRITE_REG(DACVidWinEnd, tmp);
 585
 586         /* Finally set up the rest of the overlay regs in the order
 587            done in the IMG driver
 588          */
 589         tmp = STG_READ_REG(DACPixelFormat);
 590         tmp = ((ulExcessPixels << 16) | tmp) & 0x7fffffff;
 591         STG_WRITE_REG(DACPixelFormat, tmp);
 592
 593         tmp = STG_READ_REG(DACHorizontalScal);
 594         CLEAR_BITS_FRM_TO(0, 11);
 595         CLEAR_BITS_FRM_TO(16, 17);
 596         tmp |= ((ulhDecim << 16) | (ulDacXScale));
 597         STG_WRITE_REG(DACHorizontalScal, tmp);
 598
 599         return 0;
 600 }