DMA for USART

[NPal.2]

Hi all,

I am trying assign DMA to USART3 channel on STM32MP1.

I assigned it appropriately in the CubeMX but it looks like it was not able to auto-generate any code regarding the DMA assignment to the USART3.

The device-tree bindings look pretty confusing to me. How can I assign it correctly?

I checked option use MDMA in the CubeMX and I can see a mdma block generated which is empty. So any directions on how to assign dma to USART3 will be really helpful and appreicated.

Thanks.

[PatrickF]

Hi,

please precise in which context you are requesting DMA with USART3. Is it for Cortex-M4 code generation with CubeMX ?

Regards.

[NPal.2]

Hi @PatrickF​  I am trying to use the USART3 in A7 context.

[PatrickF · Accepted solution]

I'm not Linux expert, but I understand the DMA channels assignment and configuration is not done statically at DT level but rather in your application.

See https://wiki.st.com/stm32mpu/wiki/Dmaengine_overview

At DT level, DMA1 (usually) will just be define as 'okay' to assign it on Linux side.

MDMA is not used directly, except for USART1 in secure mode (OpTEE)

Regards.

[Olivier GALLIEN]

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