Configure or flash FPGA ?

This article explain the difference between flashing FPGA and configuring FPGA.

figure 1 - Flash and FPGA

• Configure FPGA : At power on, the FPGA is not configured. FPGA configuration is the action of transfering the bitstream from the processor RAM to the FPGA.

BIOS> fpga load 0 ${loadaddr}

• Flash firmware : It is possible to save the FPGA configuration under the Flash memory of the APF. Flashing firmware is the action of transfering the bitstream from the processor RAM to the flash memory.

BIOS> run flash_firmware

• Auto-load : It is possible to configure U-Boot to configure the FPGA with the configuration saved in Flash memory on the boot. To do that simply set the U-Boot environment variable firmware_autoload to 1 :

 BIOS> setenv firmware_autoload 1
 BIOS> saveenv

Warning: Before setting the auto-load variable, be sure that your fpga binary file is correct. If not your board hang up at U-Boot starting and you will need an U-Boot recover to fix it.