Comprehensive Real-World Guidance for Every Embedded Developer and Engineer
This book brings together indispensable knowledge for building efficient, high-value, Linux-based embedded products: information that has never been assembled in one place before. Drawing on years of experience as an embedded Linux consultant and field application engineer, Christopher Hallinan offers solutions for the specific technical issues you're most likely to face, demonstrates how to build an effective embedded Linux environment, and shows how to use it as productively as possible.
Hallinan begins by touring a typical Linux-based embedded system, introducing key concepts and components, and calling attention to differences between Linux and traditional embedded environments. Writing from the embedded developer's viewpoint, he thoroughly addresses issues ranging from kernel building and initialization to bootloaders, device drivers to file systems.
Hallinan thoroughly covers the increasingly popular BusyBox utilities; presents a step-by-step walkthrough of porting Linux to custom boards; and introduces real-time configuration via CONFIG_RT--one of today's most exciting developments in embedded Linux. You'll find especially detailed coverage of using development tools to analyze and debug embedded systems--including the art of kernel debugging.
• Compare leading embedded Linux processors
• Understand the details of the Linux kernel initialization process
• Learn about the special role of bootloaders in embedded Linux systems, with specific emphasis on U-Boot
• Use embedded Linux file systems, including JFFS2--with detailed guidelines for building Flash-resident file system images
• Understand the Memory Technology Devices subsystem for flash (and other) memory devices
• Master gdb, KGDB, and hardware JTAG debugging
• Learn many tips and techniques for debugging within the Linux kernel
• Maximize your productivity in cross-development environments
• Prepare your entire development environment, including TFTP, DHCP, and NFS target servers
• Configure, build, and initialize BusyBox to support your unique requirements
11.2.1. Cross-Compiling BusyBox
11.2.1. Cross-Compiling BusyBox
As mentioned at the beginning of the chapter, the authors of BusyBox intended the package to be used in a cross-development environment, so building BusyBox in such an environment is quite easy. In most cases, the only requirement is to specify the prefix to the cross-compiler on your development workstation. This is specified in Build Options in the BusyBox configuration utility by selecting the option to build BusyBox with a cross-compiler. You then are presented with an option to enter the cross-compiler prefix. The prefix you enter depends on your cross-development environment. Some examples include xscale_be- or ppc-linux-. We cover this in more detail in the next chapter when we examine the embedded development environment.
The final option in Listing 11-1 is for any extra flags you might want to include on the compiler command line. These might include options for generating debug information (-g), options for setting the optimization level (-O2, for example), and other compiler options that might be unique to your particular installation and target system.