Bootloader transplants S3C44B0 of uClinux

Compiling some function codes that are far away from other parts of the core and are not frequently used into loadable modules will help reduce the length of the kernel, reduce the memory consumed by the kernel, and simplify the impact on the kernel when the corresponding environment changes for this function. Many functions can be handled in this way, such as network card support, support for file systems such as FAT, etc.

After configuring the kernel, execute the following commands in sequence:
make dep; make clean; make lib_ only; make user_ only; make romfs; linux.bin, linux.data, linux.text, image.bin and other target files will be generated under uClinux-dist/images/. Errors may occur during compilation and need to be debugged and modified based on the error information.

　　3.4 Download and run the kernel

　　(1) We will burn the U-Boot target file u-boot.bin that has been transplanted to the target hardware platform through JTAG. The starting address should start from 0 when burning, and run from the 0 address after the target board is powered on. Start running the transplanted bootloader. We can detect the serial port output of the target board through HyperTerminal under Windows or minicom under Linux;

　　(2) Use the U-Boot command tftpboot to download our transplanted kernel, tftpboot c008000 linux.bin; go c008000. Through the above two steps, uClinux can be downloaded and run.

　　After the system starts, it first executes the bootloader, completes the initialization task of the hardware device, and then hands over the operation control to the uClinux kernel, and the uClinux system starts running.

　　4 Conclusion

　　Due to the source code openness of the Linux operating system and the good performance of the ARM microprocessor, how to transplant the Linux system to the ARM platform has attracted more and more attention. Operating system transplantation is a prerequisite for building an embedded system based on ARM microprocessors. Designing the bootloader separately from the system kernel can make the software structure clearer, and the function of the former can be used to flexibly implement multiple ways of booting the system. .

　　The innovation of this paper: This paper uses transplantation of U-Boot as the system bootloader, thus realizing uClinux-2.6 kernel transplantation. As a powerful bootloader, U-Boot is suitable for multiple platforms and can boot multiple operating systems. Its powerful functions can be used to implement multiple download and boot methods of the system kernel. It is necessary to master its transplantation method. uClinux2.6 The kernel has better support for hardware platforms. During the transplantation process, you should pay attention to the differences between different hardware platforms.