How to use scatter/gather mem2mem transfer with fsl-qdma driver

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How to use scatter/gather mem2mem transfer with fsl-qdma driver

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basudebdas
Contributor I

Hi, I am developing a driver module on LS1046A processor (and Linux OS) and want to use fsl-qdma driver for dma data transfer from memory to memory. I am looking for some reference/documentation on how to use the fsl-qdma driver for this purpose. Looking at the fsl-qdma source code, I see that the current memcpy call only supports one source buffer and one destination buffer. No scatter/gather list support. I want to transfer from a list of buffers to a memory destination. How shall I use source scatter/gather list with this fsl-qdma driver ?  I dont see DMA_SG option also when requesting a channel. Any pointer or advice will be very much appreciated.

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Pavel
NXP Employee
NXP Employee

The SG mode has been removed from kernel dma engine driver.

If you want to use SG mode please use the LSDK branch linux-4.9.

Have a great day,
Pavel Chubakov

 

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gyosunshim
Contributor III

Hi, Pavel Chubakov.

It is a long time ago, but I am facing the same problem, so I will reply with any questions.

I am using LSDK1803, and I read the above and used 4.9 because of SG mode.

Why is SG mode removed in higher versions? Is there a better mod to replace?

Thank you,
Best regards.

Gyosun.

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