Research Of Embedded Linux Device Drivers Concurrency Control

In the embedded Linux system, device drivers not only take an important role to connectthe hardware and application software, but also are an important part of the Linux kernel. Andthey are very important in the system development process. In the Linux system (this articleis a2.6version) which supporting multi-process, multi-threaded and kernel preemption, thedevice drivers’ concurrency control are key technology.Analyzing the Linux operating system’s concurrent execution principle and the processof the execution path’s accessing to a shared device concurrently are conducive to developstable device drivers. Using concurrency control mechanism (spin locks and semaphoresrationally) can make the process access the system device correctly, and can avoid the errorsthat cause the system stopping and not moving forward occur in the process of accessingdevice.Firstly, in this paper, by analyzing the Linux system’s space, process scheduling, userpreemption, kernel preemption, and the Linux interrupt mechanism, it having summed up theconcurrent execution’s process and timing in the single-processor embedded Linux system,and made the following point of view:(1) In the single-processor embedded Linux system, the concurrent execution’s paths areprocess and interrupt handler.(2) The process’s switch and the external interrupt result in the concurrent execution.The same priority process’s switch, the different priority process’s switch and externalinterrupt may be willing to interrupt the process or interrupt handler that are implemented,which causing the race of accessing device.(3) By setting reasonable spin locks or semaphores to the device drivers’ critical regioncan ensure that all of the execution path can access the device correctly.And then device drivers’ concurrency control methods are put forward according to theprinciple of embedded Linux device drivers’ concurrency control. Finally, it has builtembedded Linux development environment, designed comparative experiments, summarized and analyzed the experimental results to verify the correctness of the view. This paper has acertain reference value to analyze and develop the embedded Linux device drivers.