[meta-xilinx] PMUFW built by meta-xilinx-standalone currently doesn't allow FPGA configuration

[Andreas Galauner]

Hi all,

I just tried the current version of meta-xilinx on my Ultrazed and found
that FPGA configuration didn't work. I tried Linux and u-boot and got
failures all the time.

I then built a PMU firmware using the Xilinx SDK which worked to my
surprise. After a lot of diffing which didn't yield any differences, a
lot of swearing and wondering what's up I copied directories from the
working XSDK project into the embeddedsw folder and when I arrived at
the xilfpga the PMUFW started working. I diffed the code again and it
was completely the same. The only difference was the directory structure.

It turns out that the files responsible for the actual ZynqMP FPGA
configuration in interface/zynqmp[1] are not picked up by the Makefile
and are never compiled. This leads to a missing backend for FPGA
configuration. It works in the XSDK, because the project creation magic
copies these two backend files into the src directory where they are
picked up and are compiled properly.

The copy_bsp.sh[2] script doesn't do that. The firmware compiles fine,
but you can't load the FPGA during runtime.

This took me a *long* time to find. I'd like to spare other people the
experience. Enabling debug output in the PMUFW should've given me a
proper error message, but I wasn't able to enable it for whatever
reason. I never got debug output to work.

- Andy

[1]:
https://github.com/Xilinx/embeddedsw/tree/master/lib/sw_services/xilfpga/src/interface/zynqmp
[2]:
https://github.com/Xilinx/embeddedsw/blob/master/lib/sw_apps/zynqmp_pmufw/misc/copy_bsp.sh