PYNQ image construction

This repo attempts to automate as much as possible the process for building an image for the PYNQ repository. Sources for dependencies are included as git submodules. After cloning, run git submodule init to initialise the submodule configuration followed by git submodule update to fetch the sources. Please note, as one of the sources is the Linux kernel, this make take a reasonable amount of time and disk space. Once the submodules are cloned, run make to create boot files for PYNQ in the boot_files directory or make rootfs.img to build the complete image

Setting up the environment

This release has been tested on an Ubuntu 14.04 LTS virtual machine under VMWare Player setup as described in the doc directory. SDSoC 2016.1 is the supported release of the Xilinx toolchain although the 2016.1 WebPack editions of Vivado and SDK could be used instead.

Stages of Building the Boot Files

Create an HDF

First task is to create an HDF representing the PYNQ board by creating a simple Vivado project and exporting the hardware. The only special configuration in the project are the PL clocks which are configured according to the Overlay guidelines.

Create Device Tree

The Xilinx Device Tree Generator add-on to SDK is used to create the sources for the device tree based on the HDF. A small script is then used to append an include to some PYNQ specific entries and dtc compiles everything together`

Create FSBL

A default FSBL project is created based in the HDF file.

Create u-boot

The Digilent Arty-Z1 board configuration is used as the template to build a u-boot image. All changes to the enviroment in u-boot are handled through a uEnv.txt file included in this repo

Create BOOT.bin

Bootgen collects the base bitstream from the PYNQ repo along the generated FSBL and u-boot elfs to create BOOT.bin

Create Kernel

The complete kernel config is included in this repo so all the makefile has to do is copy it in to the kernel sources and compile.

Create Root Filesystem

The root filesystem is created by calling make rootfs.img. This requires a new version of qemu to be installed in /opt/qemu and the appropriate binfmt utils installed for your kernel. Other required packages are multistrap and crosstools-ng which should be on the PATH. Building the rootfs also recompiles the kernel as a debian package so that the modules and headers can be easily installed.

Updating Components

The version of Vivado/SDK on the PATH when make is invoked should be the version used to compile the base bitstream. The Kernel version and DTG sources should be upgraded in lockstep. Using git submodules allows the versions of each repository used to be recorded unambiguously.