App note: FPGA configuration from SPI Flash memory using a Microprocessor

From Xilinx application note on FPGA configuration method:

This application note describes a simple and efficient FPGA configuration method that utilizes a microprocessor to configure an FPGA device from a Serial Peripheral Interface (SPI) flash memory. This method reduces hardware components, board space, and costs. Reference hardware design and firmware are included to illustrate the methodology.