AM623: How to get SPI to use DMA to transfer data?

lin yang

Part Number: AM623

Hi Experts:

I want SPI to transfer data using DMA, which should be possible to transfer using PDMA according to the AM62X TRM, but I didn't find an example of this.

over 2 years ago

0 Jianzhong Xu over 2 years ago

TI__Guru 60280 points

Hello,

Are you using Linux or RTOS?

Regards,

Jianzhong

0 lin yang over 2 years ago in reply to Jianzhong Xu

Prodigy 70 points

Hello,

I'm using Linux on A53.

Regards,

Lin yang

0 Andreas Dannenberg over 2 years ago in reply to lin yang

TI__Guru 70192 points

Hi,

the McSPI driver in Linux already is using DMA using the DMAEngine framework, see https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/spi/spi-omap2-mcspi.c?h=ti-linux-5.10.y#n375 .

Regards, Andreas

0 lin yang over 2 years ago in reply to Andreas Dannenberg

Prodigy 70 points

Hi,

Sorry I may not have made it clear, what I want to know is how to configure dts so that the SPI DMA works, I don't know which DMA channel to use, other dts do not seem to have a similar configuration, and the existing DMA configuration does not seem to be PDMA, not sure if it can be used for SPI.

Regards,

Lin yang

0 lin yang over 2 years ago in reply to lin yang

Prodigy 70 points

Hi,

I guessed the DMA configuration of SPI based on the code, but it doesn't seem to work, can you give some suggestions?

Regards,

Lin yang

0 Andreas Dannenberg over 2 years ago in reply to lin yang

TI__Guru 70192 points

Hi Lin,

lin yang said:
Sorry I may not have made it clear, what I want to know is how to configure dts so that the SPI DMA works

ah ok I understand. By default the DMA is not enabled/configured for SPI use (as of SDK v8.6, as well as for the current SDK v9.0), so you need to update the DTS file to add DMA support. Please refer to the below E2E post for details and how-to.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1223699/am625-how-to-enable-dma-for-mcspi/4622078#4622078

Regards, Andreas

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AM623: How to get SPI to use DMA to transfer data?