Design And Implementation About ALSA Audio Driver Based On The ARM Platform

The main content of my paper is to write an ALSA driver to control the audio stream for our audio codec chip, the hardware platform is Samsung2440CPU based ARM9and our audio codec chip.The paper introduce the entire development process, firstly it is about the general embedded development process and related concepts, mainly about the ARM architecture which is used in my paper; Software operation system is the linux2.6.32kernel, and paper analysis a series of related content about linux operation system, then I explain the process about how to set up our develop and debug environment. Secondly we go to the key points about ALSA develop, begin with Audio Interface Specification I2S of related concepts about audio, then analysis the ALSA structure, and finally introduce the implementation process of the ALSA driver. There are three major parts about ALSA driver:decode driver, machine driver, platform driver. Only we set up all these three parts we can complete our ALSA driver. Then we should abstract the sound card, the sound card and its components which are related to the operations of the audio chip registers, so we complete my ALSA driver.When our driver is completed we should begin to test it, the uImage should be transported to the develop board via TFTP after the diver is complied into the kernel.The file system is the ramdisk which has already done, Similarly the application executable file is transmitted over the NFS network.The final part is testing. ALSA driver need to use the ALSA lib layer in the middle when be called by the application layer code to operate the hardware, this is the role of ALSA. It will provide a unified interface to different audio chip in different platforms, so developers do not need to write the driver again when change the platform. ALSA Utiles tools need to be called when Test-driven interface, there will generate many executable files such as aplay or amixer which can be used to call the interfaces of driver with different permanents,so I can get my test results and bugs or not. The test results show that the sound card driver is successful and achieve normal ALSA audio chip support.