SoCFPGA EPCS/EPCQx1 mini howto:
- Instantiate EPCS/EPCQx1 Serial flash controller in QSys and rebuild
- The controller base address is the "Base" in QSys + 0x400
- Set MSEL[4:0]=10010 (AS Standard)
- Load the bitstream into FPGA, enable bridges
- Only then will the driver work
