FPGA registers access from Linux userspace on OPOS93 SP

Introduction

The flexio_armabus kernel driver is mapping the FPGA address space in a file /dev/armabus. For further informations, see OPOS93_SP Interfaces description.

Setting address

Address should be set using the lseek() C function on the /dev/armabus file.

int fd = open("/dev/armabus", O_RDWR);
lseek(fd, 8, SEEK_SET); // Set address 0x0008
close(fd);

Read/write

Access to the bus should be done using read() and write functions.