Mastering embedded Linux

This intensive four-day course will teach you the techniques required to build Linux into embedded systems. During the hands-on sessions you will learn about the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the Linux kernel and the root filesystem. You will create each of these elements from scratch, and discover out how to automate the process using tools such as Buildroot and the Yocto Project. In later sessions you will delve into architectural issues such as file system layout, how to split functions between user and kernel space and real-time programming. You will also find out how to debug and profile code at both the application level and within the kernel so that you will be able to identify bugs and resolve performance bottlenecks.

The theory is backed up with hands-on labs where you will get a chance to try out all the concepts covered in the presentations. At the moment it is only available on-line, using a virtual classroom. You will build a fully-functional system using the QEMU emulator as the target.

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Duration

4 days

Upcoming courses

None scheduled: contact us to request a quote

Audience

This course is ideal for software engineers who are familiar with embedded devices but need to apply that knowledge to Linux development, and to those who are familiar with Linux, but want to apply that knowledge to embedded systems

Prerequisites

Essential: good knowledge of the C programming language, since this is used in the programming portions of the course
Desirable: either a good background in embedded devices, or a reasonable proficiency in Linux command-line tools. Delegates with neither will find the learning curve rather steep

Course materials

All students will receive:

  • Electronic copies of the presentations and lab notes
  • Worked solutions to the lab sessions

Course outline

Introduction to Embedded Linux

  • Linux as an embedded operating system
  • Working with open source licenses
  • The four elements of embedded Linux: toolchain; bootloader; kernel and root filesystem

The bootloader and kernel

  • Booting embedded hardware: initialization; loading Linux; system maintenance
  • Looking at U-Boot as an example
  • The Linux kernel: main-line and vendor kernels; the development cycle
  • Configuring and cross-compiling Linux

Device trees

  • Device tree syntax
  • Modifying a device tree

Root filesystem

  • Directory layout
  • Important programs: init and the shell
  • Using Buildroot to create a root filesystem

File systems and flash memory

  • Types of flash memory: NOR, NAND and eMMC
  • Choosing the right file system: UBIFS, JFFS2, EXT4 and squashfs
  • Designing a robust storage strategy

Embedded Linux build systems

  • Using Buildroot for small projects
  • Adding Buildroot packages and overlays
  • Using the Yocto Project for larger projects
  • Yocto Project meta layers and recipes

Init, device management and logging

  • Choices for init: Busybox, SysV, systemd
  • SysV init scripts and runlevels
  • Systemd: writing systemd units
  • Configuring network interfaces
  • Device managers: populating /dev
  • Options for the system log daemon

Understanding Toolchains

  • Choosing the C-library
  • Getting to know your toolchain – sysroot
  • The art of cross compiling
  • Introduction to GNU Autotools

Debugging using GDB

  • Debugging applications remotely using gdbserver
  • Crash analysis of core dumps

Linux device drivers

  • Writing kernel code: kernel modules
  • Anatomy of a simple device driver
  • Kernel debugging: interpreting an oops
  • Debugging using kgdb

Profiling and tracing

  • Tools for profiling: top, perf
  • Tools for tracing: strace, ftrace

Real time

  • Linux scheduling policies
  • Kernel preemption and scheduling latencies
  • Approaching hard real-time with the PREEMPT_RT patch