www.it-ebooks.info www.it-ebooks.info Praise for Embedded Android “This is the definitive book for anyone wanting to create a system based on Android. If you don’t work for Google and you are working with the low-level Android interfaces, you need this book.” —Greg Kroah-Hartman, Core Linux Kernel Developer “If you or your team works on creating custom Android images, devices, or ROM mods, you want this book! Other than the source code itself, this is the only place where you’ll find an explanation of how Android works, how the Android build system works, and an overall view of how Android is put together. I especially like the chapters on the build system and frameworks (4, 6, and 7), where there are many nuggets of information from the AOSP source that are hard to reverse-engineer. This book will save you and your team a lot of time. I wish we had it back when our teams were starting on the Frozen Yogurt version of Android two years ago. This book is likely to become required reading for new team members working on Intel Android stacks for the Intel reference phones.” —Mark Gross, Android/Linux Kernel Architect, Platform System Integration/Mobile Communications Group/Intel Corporation “Karim methodically knocks out the many mysteries Android poses to embedded system developers. This book is a practical treatment of working with the open source software project on all classes of devices, beyond just consumer phones and tablets. I’m personally pleased to see so many examples provided on affordable hardware, namely BeagleBone, not just on emulators.” —Jason Kridner, Sitara Software Architecture Manager at Texas Instruments and cofounder of BeagleBoard.org “This book contains information that previously took hundreds of hours for my engineers to discover. It is required reading for any new person that is working with Android on my team.” —Dr. Mark Micire, Researcher in Space and Mobile Field Robotics, Carnegie Mellon University www.it-ebooks.info “Thanks to this book, for the first time embedded system developers have access to an open and vertically integrated stack that contains everything they need to build robust and high- performing Linux-based products. Android’s revolutionary execution model transcends phones and tablets, and its application developer platform is unmatched in the industry for features and development speed. This book will give developers a valuable resource for understanding everything between the application layer and the kernel, and how to extend and change things to create an infinite variety of Androids.” —Zach Pfeffer, Tech Lead for Linaro’s Android team “Finally, a book on the Android platform from a systems perspective! There are plenty of books on creating Android applications, but for too long no single, comprehensive source for information on Android’s internals. In Embedded Android, Karim has collected a vast quantity of material that is essential and helpful for Android systems programmers and integrators (although, to be sure, application developers would benefit from a reading as well). Karim’s copious examples, references, and explanations are gleaned from his extensive experience with and analysis of Android. It’s the book I wish I had had when I walked my own trail of tears learning Android for work at Sony. With this book, I could have saved myself months learning the ins and outs of Android. No doubt this will be the canonical reference book for Android system developers for years to come.” —Tim Bird, Senior Staff Engineer, Sony Network Entertainment, and Architecture Group Chair, CE Workgroup of the Linux Foundation “Karim Yaghmour’s book is an excellent guide for those wishing to get into the burgeoning field of Android-based embedded projects and products. The book covers the full range from kernel support through licensing and trademark issues, including information on running Android systems in “headless” mode as well. This book deserves a place on every serious embedded Android developer’s bookshelf.” —Paul E. McKenney, IBM Distinguished Engineer and Linux Kernel RCU Maintainer “Although Android is officially designed for mobile and tablet segments, it’s unquestionably getting considered for many other product segments, like automotive, UI panels like HMI, wearable gadgets, and so on. This book is highly recommended, as it covers all the essential fundamentals and concepts that help developers port and develop Android-based solutions for both mobile and nonmobile product segments.” —Khasim Syed Mohammed, Lead Engineer, Texas Instruments www.it-ebooks.info “A great resource not only for embedded Android developers, but also for Android app developers to learn the wiring below the Java surface.” —Lars Vogel, CEO, vogella GmbH “Once again, Karim has hit the nail on the head. If you’re interested in porting Android to a new device or just interested in the guts of how Android runs on a piece of hardware, this is the book you’ve been searching for. This book leads you through all of the facets of build- environment setup, getting the AOSP sources, adding your hardware to the Android sources and deploying a new Android build to the hardware. It discusses the underpinnings of Android including the HAL and how to give your custom hardware support within the Android framework. In short, of all the books on Android, this is the one book that targets the Android device builder rather than Android application developer or end user. I just wish this book would have been available when I first got into Android porting. It could have saved me months of trial and error efforts.” —Mike Anderson, Chief Scientist, The PTR Group, Inc. “Embedded Android has been a great resource for our company. It is a must-have when porting Android to new hardware or integrating new features at a low level. Karim is a great instructor, and his writing captures his style well.” —Jim Steele, VP of Engineering, Sensor Platforms “Embedded Android is a must-read for anyone who wants to seriously work the Android internals and bring up Android on new platforms. It helps in navigating the extensive AOSP codebase, and understanding the overall architecture and design of the system.” —Balwinder Kaur, Senior Member, Technical Staff, Aptina Imaging “So you thought you knew about Android internals? Well, think again! Chapter after chapter, you’ll discover what’s behind the scenes and why Android is not just another embedded Linux distribution. Get yourself ready for stepping into a whirlpool, ’cause Embedded Android is a gold mine for anyone looking to do serious hacking on Google’s OS.” —Benjamin Zores, Android Platform Architect, Alcatel-Lucent www.it-ebooks.info “Definitely one of the most valuable and complete resources about the Android system stack. A must-have for every Android system engineer.” —Maxime Ripard, Android Lead, Free Electrons “When I was handed a development board running Linux, and was told to ‘get Android running on it,’ it was difficult to find much information about how to bring Android up on a new device. Luckily for me, Embedded Android became available about the same time that I was beginning development. What a lifesaver! Embedded Android gave me the kick- start I needed to understand the underpinnings of Android and what I would need to do to bring Android up on a new piece of hardware. I loved all the details and background, from the boot sequence to the build system. After having read Embedded Android, I felt I had a much better grasp of Android and how it interacted with the Linux kernel.” —Casey Anderson, Embedded Systems Architect, Trendril www.it-ebooks.info Karim Yaghmour Embedded Android www.it-ebooks.info Embedded Android by Karim Yaghmour Copyright © 2013 Karim Yaghmour. All rights reserved. Printed in the United States of America. Published by O’Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (http://my.safaribooksonline.com). For more information, contact our corporate/ institutional sales department: 800-998-9938 or corporate@oreilly.com. Editors: Andy Oram and Mike Hendrickson Production Editor: Kara Ebrahim Copyeditor: Rebecca Freed Proofreader: Julie Van Keuren Indexer: Bob Pfahler Cover Designer: Randy Comer Interior Designer: David Futato Illustrator: Rebecca Demarest March 2013: First Edition Revision History for the First Edition: 2013-03-11: First release See http://oreilly.com/catalog/errata.csp?isbn=9781449308292 for release details. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. Embedded Android, the image of a Moorish wall gecko, and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a trade‐ mark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. ISBN: 978-1-449-30829-2 [LSI] www.it-ebooks.info To Anaïs, Thomas, and Vincent. May your journeys be filled with the joys of sharing and discovery. www.it-ebooks.info www.it-ebooks.info [...]... community efforts typically start by forking the official Android source releases to create their own Android distributions with custom features and enhancements Such is the case, for instance, with the CyanogenMod project, which provides aftermarket images for power users There are also efforts by various silicon vendors to provide Android versions enabled or enhanced for their platforms For example,... together mainly as a marketing front to show the industry’s support for Android, but that in practice it has little to no bearing on Android s development Getting Android There are two main pieces required to get Android working on your embedded system: an Android- compatible Linux kernel and the Android Platform For a very long time, getting an Android- compatible Linux kernel was a difficult task; it continues... good idea of what you’ll find in Android Also note that every new Android release brings in its own new set of features Check the Platform Highlights published with every version for more information on features and en‐ hancements In addition to its basic feature set, the Android platform has a few characteristics that make it an especially interesting platform for embedded development Here’s a quick... support for all Android- required components for their products The Android Platform is essentially a custom Linux distribution containing the userspace packages that make up what is typically called Android. ” The releases listed in Table 1-1 are actually Platform releases We will discuss the content and architecture of the Platform in the next chapter For the time being, keep in mind that a Platform... typically used with Android, the memory layout of typical Android systems, the typical development setup to use with Android, and a couple of evaluation boards you can easily use for prototyping embedded Android systems Chapter 6, Native User-Space, covers the root filesystem layout, the adb tool, Android s command line, and its custom init Chapter 7, Android Framework, discusses how the Android Framework... development teams customizing Android for use in their embedded designs And I’ve learned enough about Android to say this: By no means is this book exhaustive There are a lot of things about Android and its internals that this book doesn’t and can’t cover This book should, nevertheless, allow you to jump-start your efforts in molding Android to fit your needs Audience for This Book This book is primarily... about embedded systems, either, and there are books on that topic, too Finally, this book isn’t about embedded Linux, which also has its own books Still, being familiar with Linux’s use in embedded systems is something of a plus when it comes to Android Indeed, though Android is a departure from all things traditionally known as embedded Linux,” many of the techniques typically used for creating embedded. .. of embedded Android systems This book will also be helpful to you if you’re interested in understanding Android s internals Indeed, customizing Android for use in embedded systems requires knowing at least some basics about its internals So while the discussion isn’t geared toward a thorough exploration of Android s sources, the explanations do show how to interact with the various parts of the Android. .. interfaces This shift in user paradigms and ex‐ pectations, combined with Android s open source licensing, have created a groundswell of interest about Android within the embedded world Unlike Android app developers, however, developers wanting to do any sort of platform work in Android, including porting or adapting Android to an embedded device, rap‐ idly run into quite a significant problem: the almost... realized that Android was very foreign Little of what I knew about Linux and the packages it’s commonly used with in embedded systems applied to Android Not only that, but the abstractions built in Android were even weirder still So began a very long (and ongoing) quest to figure things out How does Android work? How is it different from regular Linux? How can I customize it? How can I use it in an embedded . www.it-ebooks.info www.it-ebooks.info Praise for Embedded Android “This is the definitive book for anyone wanting to create a system based on Android. If you don’t work for Google. of books on creating Android applications, but for too long no single, comprehensive source for information on Android s internals. In Embedded Android, Karim