Open Source Summit + ELC Europe 2019

Jason will introduce attendees to the Techlab embedded learning hw kit which will be used through the rest of this Embedded Linux learning track.

U-Boot is the universal bootloader used on a vast majority of embedded systems, development kits, products and so on. This session is an introduction into the U-Boot bootloader, including a hands-on part, and covers practical topics like identifying that the board is running U-Boot, accessing and exploring the U-Boot shell, including advanced scripting techniques to make life easier, obtaining information about the current hardware, accessing buses and storage and finally booting the kernel. Furthermore, since every embedded project has it’s a unique set of requirements, U-Boot customization topics are briefly touched at the end of the session.

Bugs happen. Identifying and fixing them is part of the development process. This tutorial demonstrates one of the key tools in the embedded Linux developer’s toolbox: the GNU Debugger, GDB.

You will begin by using GDB to debug a program running on a target device. You will learn about debug symbols: how build them into programs and libraries, and the places that GDB will go looking for them. Next, you will perform basic debugging tasks, including setting breakpoints, stepping through code, examining variables and modifying variables. After that you will lean about GDB command files and how they can help you by automating certain tasks. You will receive a handy GDB cribsheet to help you with all of this. If time allows, we will discuss how to use GDB to analyse core dumps so that you can perform a post-mortem on a crashed program

In the tutorial we're going to cover the basics of Linux kernel development, from the idea (or a bug found!) to the change integrated into the Linux mainline.

We'll start from setting up the environment: the Linux kernel source, the compiler and debugger. Options like embedded debugger and using virtual machines in case of kernel crashes will be taken into account too.

Then we'll cover the implementation of the patch, showing where to look for the information about APIs, how to correctly use the Linux coding style and write patch descriptions. The audience will also learn about the unit test mechanism and testing in the kernel in general.

Then we're going to move to the process of getting the patch to the mainline: starting from where and how to send it. One of the scary points for new developers is the review process and we're going to demystify it.

Pre-requirements: C coding, usage of Makefiles. No previous Linux kernel development experience necessary.

This introductory presentation will explain the Device Model, the mechanism that the Linux kernel offers to bind drivers to devices and to expose each device to user space. Even though the way to detect or describe devices can depend on the bus or CPU architecture, the infrastructure binding devices with drivers is universal and therefore applies to all types of device drivers in the Linux kernel. Similarly, exposing devices to user space always follows the same philosophy.

This session won't have practical labs but will be illustrated by studying several types of drivers, showing various ways of managing multiple devices in the same driver, and implementing the references between devices managed by a bus and devices that userspace sees. Of course, the use of the Device Tree will play an essential part of the picture. Even though there are neither trees nor kernels in Antarctica, penguins love them!

A GPIO, or “General Purpose Input/Output” is a programmable digital pin which allows you to implement either input or output. They have no default behaviour but can be configured in a number of ways. They are often shared with other embedded buses which further requires you to choose how you want to use the pin at any particular time. This class will cover using libgpio and using GPIOs from userspace.

This tutorial will briefly introduce the Linux IIO and Input subsystems to students. In addition, the tutorial will instruct the students in how to gather information from hardware documentation to assist in their software development. The focus of the tutorial will be a guided hands-on lab where the students write a new driver that leverages the IIO and Input kernel subsystems. Students will create their own game controller driver and use it to play a game on their devices. The lab will be conducted using the provided hardware kit.

Buildroot is a popular tool to build customized and lightweight embedded Linux systems. By automating the complete process of cross-compilation, it provides an easy and efficient way to build from the source code your toolchain, Linux kernel, bootloader and root filesystem images, using the 2500+ existing packages. Used by large companies such as GoPro or Tesla, it provides an interesting alternative to the popular Yocto/OpenEmbedded build systems.

This session will allow participants to set up a basic Buildroot system for the PocketBeagle platform: configuring Buildroot, doing a first build, flashing the system, and discovering how to improve the configuration with additional software components.