iMX8MM: RDC configuration

[Raal]

Hello,

we're using an iMX8MM and my part within the project is to check the Cortex-M4 possibilities. An EVK is available. I wonder where and when RDC is configured using Linux, but I've only basic knowledge about Linux internals.

I found the RDC configuration within ATF in imx8mm_bl31_setup.c, but here only the UARTs are configured. I also found some other spots using RDC, but those are bound to iMX8MN or iMX8MP. For other devices than iMX8MM I saw device tree entries for RDC, but it seems that's not the case for iMX8MM.
I assume the RDC must always be fully configured for the used peripherals, but I couldn't locate the corresponding source codes. Can someone clarify, please?

Regards

[Raal]

Hello @Chavira 

thank you for your answer. As I mentioned I found those codes already, but I couldn't find any information about if and where the RDC is configured for other peripherals. I assumed that configuration of RDC is mandatory, otherwise the system wouldn't run. But since there are no other places where RDC is configured it seems that it's only an option to use RDC. Can you confirm that?

Regards

[Chavira]

Hi @Raal!

Yes, if you want to configure the RDC, it should be configured on
imx8mm_bl31_setup.c.

Best Regards!
Chavira

[Chavira]

Hi @Raal!

Thank you for contacting NXP Support!

RDC PDAP registers are configured in ATF.

Please refer to imx_rdc_cfg in  https://github.com/nxp-imx/imx-atf/blob/lf_v2.6/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c

Unfortunately, we don´t have documentation about that, but you have the UART examples on imx8mm_bl31_setup.c

Please refer to the codes related to RDC configuration:

https://github.com/nxp-imx/imx-atf/blob/lf_v2.6/plat/imx/imx8m/imx8mm/include/imx_sec_def.h

https://github.com/nxp-imx/imx-atf/blob/616a4588f333522d50a55bedd2b9a90a51474a75/plat/imx/imx8m/imx_...

https://github.com/nxp-imx/imx-atf/blob/616a4588f333522d50a55bedd2b9a90a51474a75/plat/imx/imx8m/incl...

Best Regards!

Chavira