Research And Implementation Of User Mode Driver For Network Device Based On Embedded Linux

With the rapid development of computer technology, computer systems are increasingly small, and the embedded systems has penetrated into all aspects of people’s lives. Linux due to the nature of open source, which the kernel can be easily customized freely, and supports a wide range of processor architecture, becoming the most popular embedded operating systems. Linux operating system with powerful networking capabilities, it can satisfy most networking requirements of various embedded devices, to perform these functions, rely on network hardware devices. Linux systems requires a reliable device driver to drive the hardware device.Device drivers commonly execute in the kernel space to achieve high performance and easy access to kernel services. Already some studies focusing on driver error with kernel for isolation, but these new driver framework continue to run in kernel mode, drivers run in kernel mode reduces the reliability of the system and increases the difficulty of programming. This paper departure from the traditional network card device driver, the methods for improving the reliability of the device driver has been an in-depth study, this paper design and implementation the user mode device driver of DM9000network card based on ARM platform. To achieve high performance and compatibility, this design allows data-handling operations critical to I/O performance to run at full speed, while management operations such as initialization and configuration run at reduced speed in user-level. Experiments shows that, implemented by the user mode driver for the device in this paper in terms of network throughput and CPU utilization are comparable with the traditional kernel mode driver, fully able to meet the performance demands of practical applications. Compared with conventional network card drivers, this design because most code moved to user space, and reducing the amount of source code of the kernel space, so as to achieve the aim to improve overall system reliability, but also has a good performance and is compatible with existing Linux kernel. This topic has high significance and practical value.