how to access to trasfer data form io to memory on ARM9 s3c2440 with DMA or without DMA

Question

I want to transfer 8 bit parallel data from IO to memory ,the data is coming very fast at speed of roughly 5 Mhz ,I am using embedded linux on ARM9 based kit by friendly arm which is using S3C2440(400Mhz) processor can any body pleas tell me where to start,my data is a video signal that is coming from a adc I have read the on internet that I can do this using DMA but I need a start ...

Answer 1

have a look at these articles to for brieif theroy

http://my.opera.com/richasn/blog/2011/01/15/application-of-dma-way-in-data-acquisition-in-arm-system

http://my.opera.com/richasn/blog/2011/01/14/application-of-dma-way-in-data-acquisition-in-arm-system

Answer 2

Forget about DMA on this device. The ADC is not available as a DMA source. One reason for this is that DMA is only useful for transferring multiple bytes/words/whatever - the overhead of setting up, starting the DMA and handling an OnCompletion interrupt makes it pointless for occasional transfers of one item. Your ADC has no buffering, just the one output register with 10 sig. bits.

Use an FIQ handler to extract the ADC result. How you buffer the output and signal it for further processing is up to you and the linux driver framework.