Embedded Linux

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Embedded Linux

Sébastien Bilavarn

Device driver development

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Outline

Ch1 – Introduction to Linux Ch2 – Linux kernel overview

Ch3 – Linux for Embedded Systems Ch4 – Embedded Linux distributions

Ch5 – Case study: Xilinx PowerPC Linux

Ch5 bis – Case study: Xilinx Zynq-7000 Linux

Ch6 – Device driver development

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Embedded Linux distributions

Introduction Embedded platforms Embedded distributions

Ubuntu

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Introduction

Embedded Linux distributions

Linux distributions are operating systems built on top of the Linux kernel

Embedded Linux distributions are often packaged for an application domain or a target platform

Mobile phones: Android, Angström, Ubuntu, Linaro Real time: RT Linux, RTAI, XENOMAI

Target platform: Linux-OMAP, ARM Linux, Xilinx Linux Kernel, etc.

There are hundreds of Linux distributions

The first question to answer when developping an

embedded Linux system is: which distribution to choose ?

The answer mainly depends on application needs

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Introduction

Current popular platforms

OMAP 3530 (beagleboard) / ARM Cortex A8 ST-Ericsson (snowball) / Dual Cortex A9

Xilinx (ML507) / PowerPC or MicroBlaze and Virtex5 ZYNQ-7000 (ZedBoard) / Dual Cortex A9 and Virtex7

Current popular Linux distributions

Ubuntu

Android

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Embedded Linux distributions

Introduction Embedded platforms Embedded distributions

Ubuntu Android Linaro

Xilinx

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Embedded platforms

Texas Instruments

Beagleboard OMAP 3530 Cortex A8

ST-Ericsson

Snowball Nova A9500 Dual Cortex A9

Xilinx

ML507 PowerPC or MicroBlaze and Virtex5

ZYNQ-7000 Dual Cortex A9 and Virtex7

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Introduction

OMAP 3530 Beagleboard / ARM Cortex A8

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Introduction

ST-Ericsson Snowball / Dual Cortex A9

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Xilinx ML507

Description

XC5VFX70TFFG1136 PowerPC 440 (400MHz) DDR2 SODIMM (256 MB) System ACE CompactFlash 10/100/1000 Ethernet MACs Video (DVI/VGA)

RS-232

2 USB ports GPIO

etc.

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Embedded Processor PowerPC440

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Xilinx ZYNQ-7000

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Embedded Linux distributions

Introduction Embedded platforms Embedded distributions

Ubuntu

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Ubuntu

Ubuntu (embedded)

Developed originally to support Mobile Internet Devices.

MID: small handheld, battery- powered mobile devices that connect to the Internet via

various wireless technologies.

Targets the ARMv7 and above Application Processor family (Cortex A8, A9 and above).

Currently supports ARM EABI, with minimum compliance with the ARMv7+VFP ISA, possibly targets Thumb2 instruction set.

Ubuntu / Beagleboard video surveillance demo

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Ubuntu

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Embedded Linux distributions

Introduction Embedded platforms Embedded distributions

Ubuntu Android Linaro

Xilinx

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Android

Android is a Linux-based operating system for mobile devices such as smartphones and tablet computers.

Developed by the Open Handset Alliance, led by Google.

Open Handset Alliance

Google, Intel, LG, Marvell, Motorola, Nvidia, Qualcomm, Samsung, T.I.

Goal: develop open standards for mobile devices.

Android code is open-source, under the Apache

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Android

Versions

Each version is named in alphabetical order, with 1.5

"Cupcake" being the first named after a dessert and every update since following this naming convention.

1.0 : Apple Pie or Alpha, version known from developers only.

1.1 : Banana Bread or Beta, version included in the first Android phone, the HTC G1/Dream.

1.5 : Cupcake, april 2009, last revision may 2010.

1.6 : Donut, sept. 2009, last revision may 2010.

2.0 (2.0.1) : version first called Eclair. Because of many bugs, it has been quickly replaced by 2.0.1 and 2.1.

2.1 : Eclair, jan 2010, last revision may 2010.

2.2 (2.2.3) : FroYo (Frozen Yogourt), mai 2010. Last

revision 2011.

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Android

Versions

2.3 (2.3.7) : Gingerbread, dec. 6th 2010. Used in small tablets.

3.0 (3.2) : Honeycomb, jan.

26th 2011. Used in large tablets and connected televisions.

4.0 (4.0.4) : Ice Cream Sandwich.

Unified version

for smartphone, tablet and Google TV, oct. 19th 2011.

4.1 : Jelly Bean, june 27th

2012. Used in Nexus 7 tablet mid-

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Android

Design

Based on the Linux kernel,

With middleware, libraries and APIs written in C

Except the Linux kernel, Linux userspace is very different from other Linux distributions.

Application software running on an application

framework which includes Java-compatible libraries based on Apache Harmony (open source free Java implementation).

Android uses a Virtual Machine (Dalvik) to produce executable (Dalvik executable) form Java bytecode.

Android does not have a native X Window System nor does it support the full set of standard GNU libraries, and this

makes it difficult to port existing Linux applications or

libraries to Android.

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Android

Design

Android's kernel is based on the Linux kernel and has

further architecture changes by Google outside the typical Linux kernel development cycle.

Android’s kernel has a few differences from the mainline Linux kernel (kernel.org).

power management (wakelocks)

Hardware platform: ARM architecture. Support for x86 from

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Android

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Embedded Linux distributions

Introduction Embedded platforms Embedded distributions

Ubuntu

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Linaro

A not-for-profit (NFP) engineering organization that works on consolidating and optimizing open source for the ARM architecture:

GCC toolchain, Linux kernel, ARM power management, graphics and multimedia interfaces.

Produces ARM tools, Linux kernels and builds of key Linux distributions (including Android and Ubuntu)