drivers/gpu/drm/nouveau/nvkm/engine/disp/hdmi.c

   1 // SPDX-License-Identifier: MIT
   2 #include "hdmi.h"
   3
   4 void pack_hdmi_infoframe(struct packed_hdmi_infoframe *packed_frame,
   5                          u8 *raw_frame, ssize_t len)
   6 {
   7         u32 header = 0;
   8         u32 subpack0_low = 0;
   9         u32 subpack0_high = 0;
  10         u32 subpack1_low = 0;
  11         u32 subpack1_high = 0;
  12
  13         switch (len) {
  14                 /*
  15                  * "When in doubt, use brute force."
  16                  *     -- Ken Thompson.
  17                  */
  18         default:
  19                 /*
  20                  * We presume that no valid frame is longer than 17
  21                  * octets, including header...  And truncate to that
  22                  * if it's longer.
  23                  */
  24         case 17:
  25                 subpack1_high = (raw_frame[16] << 16);
  26                 /* fall through */
  27         case 16:
  28                 subpack1_high |= (raw_frame[15] << 8);
  29                 /* fall through */
  30         case 15:
  31                 subpack1_high |= raw_frame[14];
  32                 /* fall through */
  33         case 14:
  34                 subpack1_low = (raw_frame[13] << 24);
  35                 /* fall through */
  36         case 13:
  37                 subpack1_low |= (raw_frame[12] << 16);
  38                 /* fall through */
  39         case 12:
  40                 subpack1_low |= (raw_frame[11] << 8);
  41                 /* fall through */
  42         case 11:
  43                 subpack1_low |= raw_frame[10];
  44                 /* fall through */
  45         case 10:
  46                 subpack0_high = (raw_frame[9] << 16);
  47                 /* fall through */
  48         case 9:
  49                 subpack0_high |= (raw_frame[8] << 8);
  50                 /* fall through */
  51         case 8:
  52                 subpack0_high |= raw_frame[7];
  53                 /* fall through */
  54         case 7:
  55                 subpack0_low = (raw_frame[6] << 24);
  56                 /* fall through */
  57         case 6:
  58                 subpack0_low |= (raw_frame[5] << 16);
  59                 /* fall through */
  60         case 5:
  61                 subpack0_low |= (raw_frame[4] << 8);
  62                 /* fall through */
  63         case 4:
  64                 subpack0_low |= raw_frame[3];
  65                 /* fall through */
  66         case 3:
  67                 header = (raw_frame[2] << 16);
  68                 /* fall through */
  69         case 2:
  70                 header |= (raw_frame[1] << 8);
  71                 /* fall through */
  72         case 1:
  73                 header |= raw_frame[0];
  74                 /* fall through */
  75         case 0:
  76                 break;
  77         }
  78
  79         packed_frame->header = header;
  80         packed_frame->subpack0_low = subpack0_low;
  81         packed_frame->subpack0_high = subpack0_high;
  82         packed_frame->subpack1_low = subpack1_low;
  83         packed_frame->subpack1_high = subpack1_high;
  84 }