The SPI-4.2 Core v7.0 supports a wide range of performance from 622 Mbps to 1+ Gbps. The Xilinx CORE Generator generates and delivers parameterizable cores optimized for Xilinx FPGAs. The core performance is selected in the CORE Generator GUI.
The performance options determine the relevant constraints in the UCF file. According to the SPI-4.2 GUI, the minimum performance that can be selected is 644 Mbps. Does the Xilinx SPI-4.2 core support 622 Mbps?
For 622 Mbps support, please use the 644 Mbps selection from CORE Generator.
This is fixed in SPI4.2 v7.1 released with IP Update #4.