The Design and Implementation of a Unified Hardware Abstraction Layer for Linux Operating System

• Main Authors: Pei-LiWang, 王裴立
• Other Authors: Jing Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/90222324756079675271

碩士 === 國立成功大學 === 電腦與通信工程研究所 === 103 === With the advance in technology of computer hardware and software, computer applications nowadays require diversity in hardware devices. Nevertheless, each hardware device needs its device driver in the software side. Taking Linux operating system as an example, each type of device must have a matching device driver in its kernel space. The application in user space communicates with the device driver through system calls. This is in fact a realization of an abstract concept that, for an application using a hardware device, it needs to communicate with the hardware device through the device driver. The commonly used approaches of the communication is invoking library functions, in user space, which are provided by hardware device maker, and this is convenient for application development. Inspired by the above, this study aims to design and implement a unified hardware abstraction layer (for short, UHAL) on Linux operating system via providing libraries for application developers, and to realize the abstraction of hardware devices. Application programs can invoke suitable application program interfaces in the libraries, without understanding the details of hardware device. The UHAL is constructed in the user space of Linux operating system. No modification of the Linux operating system is required and the design can be applied to various devices. The works in this study includes: (1) Develop a unified structure for developers to make use of the logical devices so that application programs can operate physical hardware devices easily. (2) Provide a management mechanism on the usage of logical devices to avoid interference among applications when the hardware device is used. (3) Support application operating interfaces that can be adapted to various scenarios. The implementation of UHAL takes advantage of Android HAL to be basic architecture to construct the desired hardware abstraction layer in Linux operating system. The result of this includes: (1) Application program interfaces and logical device server which support application development in various scenarios. (2) Logical device management system which manages the usage of logical devices. (3) Non-traditioned logical devices including sensors, GPS, and vibrators. (4) Providing user management interface for users to operate this system. The main contribution of this work is the construction of a unified hardware abstraction layer for Linux operating system with a management mechanism. The unified hardware abstraction layer can be applied to various devices, including existing devices equipped on Linux operation system. When applications operate various devises on Linux operation system, the hardware devices can be accessed via the structure proposed in this study.