FSL_XCVR_FIFO_WMK_RX
val = FSL_XCVR_EXT_CTRL_RX_FWM(FSL_XCVR_FIFO_WMK_RX);
#define FSL_XCVR_MAXBURST_RX (FSL_XCVR_FIFO_WMK_RX >> 2) /* 16 */