The Structure Of The Hardware Abstraction Layer Based On Multi-Domain And The Research Of Its Application In Real-Time Linux

With the increasing real-time requirements in embedded area, endless stream of Real-time Operation Systems appear. However, the high cost of traditional Real-time Operating System and application compatibility issues greatly limit the scope of its applications. A solution is to use and modify General Purpose Operating System to obtain the real-time performance. Linux, with open source codes,supporting a rich library functions as well as a powerful development tool, makes it a first choice for real-time modification.There are mainly two ways to enhance Linux to support real-time requirements. One is to directly modify the Linux kernel, it can only meet the requirements of soft real-time. The other is a dual kernel approach, so that a real-time co-kernel can run side-by-side with Linux on the same hardware. According to characteristics of dual-kernel mechanism, this paper research a dual-kernel approach based on Adeos (Adaptive Domain Environment for Operating System), namely Xenoami/Linux Real-time Operating System. It relies on Interrupt Pipeline of Adeos. Adeos is a hardware abstraction layer based on multi-domain, which controls all the hardware interrupts and makes Linux kernel and Xenomai were achieved respectively as one of its domain.Based on the above understanding, this paper in-depth studies the key technology of Adeos, for example, Interrupt Pipeline mechanism and domain management mechanism. Then we analyze the realization of Adeos in Linux kernel and Xenomai, And analyze the particular features of Xenomai, these include:supporting for the skins structure of multiple RTOS(Real-time Operating Sytstem) API emulations, unique Native API, real-time nucleus which provides special services for the upper interface, mixable execution modes with the Interrupt Shield mechanism and RTDM (The Real-Time Driver Model). The paper also makes real-time performance evaluation both external interrupt response latency and task scheduling latency. Finally, to verify feasibility of real-time dual-kernel approach based on Adeos, this paper designs and implements an application about multiple domains running coordinately based on Adeos. It has certain practical meanings.