LatticeXP2: Can I connect the SSPIA primitive such that both the JTAG interface and the user logic in the FPGA fabric can access the SSPI Port?
No, it is not possible to set PERSISTENCE = ON in order to preserve the JTAG to SPI port in the configuration logic while simultaneously using the SSPIA component to access internal configuration logic from the FPGA fabric (PERSISTENCE = OFF). If persistence is off and the JTAG attempts to connect to the SPI port, nothing will happen as the internal configuration mux is switched to the FPGA fabric.
As a potential resolution, you can use an external tri-state buffer on your board and route general purpose I/O pins as your SPI interface from the XP2.