topic Re: [I.MX8M Plus] using DMA to do memory copy from RAM to RAM in i.MX Processors

[I.MX8M Plus] using DMA to do memory copy from RAM to RAM

linzhenggang1 — Tue, 20 Feb 2024 07:37:25 GMT

Is it possible to do a RAM-to-RAM memory copy using DMA?

If yes, how should we do that in Linux?

P.S. We are using BSP L6.1.22

Re: [I.MX8M Plus] using DMA to do memory copy from RAM to RAM

Bio_TICFSL — Wed, 21 Feb 2024 15:06:12 GMT

Hello,

Yes it is possible, but you need to clarify which memory to what memory are you using, you can use the provided driver in the BSP.

Regards

Re: [I.MX8M Plus] using DMA to do memory copy from RAM to RAM

linzhenggang1 — Wed, 21 Feb 2024 23:04:05 GMT

Thank you for your reply.

Sorry, I don't understand the meaning of "which RAM and what RAM" you said.
I just want to do a memory copy in a user-space application(not from or to a peripheral) by using DMA to reduce my CPU usage.

If it is possible, could you please show me which part of the BSP I should use to do that?

Thank you very much!

Re: [I.MX8M Plus] using DMA to do memory copy from RAM to RAM

Bio_TICFSL — Thu, 22 Feb 2024 14:03:51 GMT

Hello,

There is no code to show how to use dma, but one can show the section 3.7.3 of the linux reference manual:

https://www.nxp.com/docs/en/reference-manual/IMX_REFERENCE_MANUAL.pdf

Regards

Re: [I.MX8M Plus] using DMA to do memory copy from RAM to RAM

linzhenggang1 — Tue, 27 Feb 2024 09:09:35 GMT

Thank you for your reply.

In 3.7.1, it said that the SDMA API driver is for other drivers(kernel mode) but not for a user space application. Is my understanding correct?

---

3.7.1 Overview
The Smart Direct Memory Access (SDMA) API driver controls the SDMA hardware. It provides an API to other
drivers for transferring data between MCU memory space and the peripherals. It supports the following features:

Re: [I.MX8M Plus] using DMA to do memory copy from RAM to RAM

Bio_TICFSL — Tue, 27 Feb 2024 14:01:18 GMT

Hello,

Yes, it's correct!, if you like to copy RAM to RAM can use the SDMA but The current drivers don't have the API to do it.

Regards