pcimem is a devmem like tool but for PCI resources access from userspace.
It allows to access BAR content from userspace using a specific access size to
access registers for instance.
gengetopt is required to generate the command line. Once installed, just run make:
$ make
Reading 4 bytes from PCIe device 07:00.0 BAR 0 at address 0x10 into standard io
# pcimem -d 07:00.0 -a 0x10 -s 4 -R 0 -r | hexdump
Writing 16 bytes to PCIe device 07:00.0 BAR 0 at address 0x10 from file
# pcimem -d 07:00.0 -a 0x10 -s 16 -R 0 -w -f input_file