RCANFD_RFFIFO_IDX
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;
u32 ridx = ch + RCANFD_RFFIFO_IDX;