Research On Porting Embedded Linux System On The Platform Of ARM9

With the increasingly widespread use of the 32-bit high performance embedded microprocessor, the embedded operating system has become one of the most important parts in embedded system. In the various embedded operating systems, Linux has been progressively widely used in embedded systems because of many advantages it has, such as open source, stable performance, powerful network capability, and wide support for various CPU architecture, etc. The premise of embedded Linux software development is to establish the development platform at first, and porting embedded Linux system is the most important step to establish that platform.The thesis systematically studies porting embedded Linux system on the platform of ARM9, and the core of the hardware platform adopted in the research is S3C2440A which is a 32-bit SoC (system-on-chip) based on ARM9 core. The main study includes following parts: porting U-Boot (a kind of bootloader), porting Linux kernel, building root file system, developing and porting Linux device drivers, porting the graphical user interface Qtopia.i) in the part of porting U-Boot, the work of porting the drivers for NOR Flash and NAND Flash has been done, and the capability of writing the image of YAFFS2 file system to NAND Flash is added;ii) in the part of porting Linux kernel, the structure of Linux kernel source and the configuration mechanism of kernel are analyzed, and the detailed way and steps of porting Linux kernel are presented; in the part of building Linux root file system, the conception and composition of root file system are analyzed in detail, then the way of porting Busybox, the installation of kernel modules, the creation of configuration files, and the way of creating the image of YAFFS2 root file system are introduce;iii) in the part of developing and porting Linux device drivers, the way of developing simple character device drivers is introduced, the LCD backlight driver and the touch screen driver for S3C2440 are developed, and the work of porting LCD display driver is done;iv) in the part of porting graphical user interface Qtopia, the way and steps of porting Qtopia 2.2.0 to ARM9 platform are presented, including the compilation and installation of tslib (an open-source touch screen support library), then the running Qtopia is tested and several problems are fixed. During the test process, the U-Boot command line running test is performed through serial console, and the running test under Linux shell command line is performed through serial console after successfully booting Linux kernel. The successful result of tests approves the porting of U-Boot and Linux kernel. The successful operation test of Qtopia approves the development of touch screen driver and the work of porting LCD display driver.The relatively complete and in-depth study about critical parts of porting embedded Linux system on the platform of ARM9 are fulfilled in this thesis, and the ways and steps of porting has been approved by experiments and practices. Although the research is done on the platform of ARM9, it also presents reference value with regard to the research on porting embedded Linux system on other platforms.