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

   1 // SPDX-License-Identifier: GPL-2.0
   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         case 16:
  27                 subpack1_high |= (raw_frame[15] << 8);
  28         case 15:
  29                 subpack1_high |= raw_frame[14];
  30         case 14:
  31                 subpack1_low = (raw_frame[13] << 24);
  32         case 13:
  33                 subpack1_low |= (raw_frame[12] << 16);
  34         case 12:
  35                 subpack1_low |= (raw_frame[11] << 8);
  36         case 11:
  37                 subpack1_low |= raw_frame[10];
  38         case 10:
  39                 subpack0_high = (raw_frame[9] << 16);
  40         case 9:
  41                 subpack0_high |= (raw_frame[8] << 8);
  42         case 8:
  43                 subpack0_high |= raw_frame[7];
  44         case 7:
  45                 subpack0_low = (raw_frame[6] << 24);
  46         case 6:
  47                 subpack0_low |= (raw_frame[5] << 16);
  48         case 5:
  49                 subpack0_low |= (raw_frame[4] << 8);
  50         case 4:
  51                 subpack0_low |= raw_frame[3];
  52         case 3:
  53                 header = (raw_frame[2] << 16);
  54         case 2:
  55                 header |= (raw_frame[1] << 8);
  56         case 1:
  57                 header |= raw_frame[0];
  58         case 0:
  59                 break;
  60         }
  61
  62         packed_frame->header = header;
  63         packed_frame->subpack0_low = subpack0_low;
  64         packed_frame->subpack0_high = subpack0_high;
  65         packed_frame->subpack1_low = subpack1_low;
  66         packed_frame->subpack1_high = subpack1_high;
  67 }