Study Of Embedded Linux And Its Device Driver Development

Embedded Linux possesses great application value and has been the hotspot of OS research, but it faces the deficiency caused by GUN. To develop Embedded OS for commercial purpose, the author applies to the research and development of Embedded Linux. This paper implements a simple Embedded Linux running in 8M Flash, and presents correlative methods and process in detail. In order to shrink the Embedded Linux so as to adapt to real-time environment, this paper probes into Linux kernel, points out the reason why it cannot adapt to real-time environment, and puts forward the improvement approaches. To improve virtual memory management mechanism, the kernel code is amended to avoid the incertitude cause by page scheduling, thus the responding speed is effectively improved. The irrationality of Linux scheduling mechanism is also analyzed, and the methods and models such as to fortify scheduling occasion and adopt double kernel are also proposed to improve it. Besides, this paper analyzes the VFS mechanism and presents improvement approach. Device driver is one of the most important components of Linux kernel. It runs in kernel status, and any problem will affect the stability or even lead to crash. This paper probes into the method of designing device driver under Linux, with emphasis on module, interruption mechanism, DMA, and presents method to avoid resource dead lock and realize cooperation and mutex among processes.Based on the research above, the author realizes a small scale Embedded Linux System, together with device driver and application software, which has been stably running in 8M Flash.Finally, this paper brings forward viewpoint for remaining problems of developing Embedded real-time Linux.