System Development for embedded Linux* OS running on Intel® Atom™ Processor

Abstract

Developing and validating embedded software stack stability and peripheral device interfaces for System-on-Chip (SoC) designs gets ever more challenging. Driving factor is the increased level of device integration and need of timely and synchronized messaging.  Additionally driving this is a fragmented and specialized software and operating system ecosystem, as well as increased time-to-market pressure. In this article we will examine how software tools can help developer productivity by using specialized development and validation technologies. Furthermore we will examine key development, analysis and debug use cases as required with most common types of embedded Intel architecture platforms.

Introduction

Over the past several years we have seen the traditional embedded market segment experience a transformation from fixed function and isolated embedded systems to a new category of intelligent systems. The transformation is changing the way people engage with and experience computing. Implications from this shift are that devices are more capable and interact with each other and these usage models demand greater performance, an increasingly capable cloud of services, and software technology and tools that support these new classes of devices. These devices are secure, connected and managed. Several industry analyst firms such as IDC* and others are seeing this shift and have created a new embedded sub-category called "Intelligent Systems". The increased usage of system-on-chip (SoC) designs in traditional embedded market segments as well as the new category of Intelligent Systems requires the developer as well as tools vendor a like to reassess the entire development process from design, code generation and debug to system performance analysis.

When developing the system software stack for embedded devices you are frequently confronted with the question how to set up the most appropriate development environment first. It helps to understand the options for approaching software development targeting embedded systems. In this article we will focus on SoC designs using an application processor based on x86 or Intel architecture. The target application processor architecture being similar to the architecture of the system most likely used by the developer for his or her development work has some unique advantages and widens the choices available.

These choices range from traditional native development of applications on the development host for later deployment on a target device to full blown traditional embedded cross development using a QEMU* based virtual machine, a remote debug connection to a physical target device and a sysroot or chroot based build environment. We will attempt in this article to shed some light on each of these options for Intel® AtomTM Processor targeted designs.

One of the most commonly used operating system for Intel architecture based embedded systems is a customized flavor of Linux*. These may range from something based mainstream Linux* distributions to custom builds from scratch. Linux distributions specialized on embedded and mobile computing applications like Wind River* Linux*, Yocto Project*, or Android*, are playing a more and more prominent role. Frequently embedded designs have a real-time requirement for at least parts of the software stack. This implies that isolating those components of the software stack that have this requirement and ensuring that they do have only minimal dependencies on the non real-time part of the software stack becomes one key challenge of developing and defining embedded systems software.

Furthermore, when talking about SoCs, understanding the interaction between all the platform components becomes vitally important. You may be developing device drivers that take advantage of special GPU features or use micro-engines and other hardware accelerators found on the platform. You may be designing the software interface for the many wireless radios found in today's small form factor devices. In either scenario, being able to analyze the message timing - making sure the variable values that are exchanged between the different platform components contain the right value at the right time, becomes important for platform software stack stability. Being able to access device configuration registers easily and in a comprehensive manner also simplifies developing device drivers and controlling platform component interaction timings.

 

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