1 Introduction and Discussion Uboot #

Start the computer program exists in daily use called BIOS, CPU development is to follow along and cured on the hardware, responsible for initializing the hardware devices simultaneously start the system. Of course, if you need to use BIOS, the system should follow the rules of the BIOS to design, it contains the interrupt vectors and kernel address and so should be in agreement on the address. Of course, our system may not be designed according to the rules, there is a direct add a layer of difficulty, to assume the task of this layer is the bootloader. bootloader to boot the system will be performed before starting hardware arrangement and software system initialization environment, such as relocation, and ultimately the system. Personally I feel that the role of highly repetitive and BIOS, so the CPU is not the BIOS, bootloader naturally replace the boot status, and the presence of system BIOS, the BIOS bootloader will follow the rules, so to start their own BIOS, the system can still eventually define their own rules, this time most of the hardware system initialization BIOS also undertaken.

Having said that, bootloader is actually a tool to start the system, but before you start to do some initialization system can make a smooth and successful start. bootloader is a tool for this type of function the same collectively, more well-known is the use of us to Uboot.

The uboot select the 1.1.6 version, can in its official website http://www.denx.de/wiki/U-Boot/ find the corresponding version of the download link. While using the patch 100ask JZ2440 veneer of test analysis. First, extract the source code files

tar -jxvf u-boot-1.1.6.tar.bz2

Then use the patch command marked our JZ2440 veneer patch

patch -p1 < ../u-boot-1.1.6_jz2440.patch

 Here patch command can be used directly view the man command usage, -p option is used to shield the differences in file paths and producers patch patched person, after the -p num developed the first num pathname shield path, here As we enter the uboot directory, so you can block out the first one.

 

Then make the appropriate board configuration options to configure, and then make the compiler. Here you can learn by reading the README under uboot directory.

make 100ask24x0_config
make

Finally get the output file u-boot.bin, programmed into our board can be used.

Simple over what content behind start doing code analysis.