Trust Zone required for DDR Memory access?

[userland]

Hi

I've been looking into the DDR driver on BL2 and noticed that Trust Zone sets up access to the memory areas, same when looking into the CW scripts. Is Trust Zone required to be initialized for the DDR memory to be accessible?

I know that MMU is not required for it but is it the same with TZ?

Thanks

[yipingwang · Accepted solution]

Yes, LSDK boot up the device with TF-A (Trusted Firmware for ARM). That required isolate resource, including DDR memory, etc.

If customer don't use OPTEE or Trust Zone, they should able to do without DDR setup. (e.g. taking the PPA approach(i.e. Non TF-A). However, PPA example are not available with LX2160A) More explanation on TrustZone/OPTEE are in the LSDK User Guide.

https://docs.nxp.com/bundle/GUID-487B2E69-BB19-42CB-AC38-7EF18C0FE3AE/page/GUID-9280C0B6-CE8D-411D-9...

https://docs.nxp.com/bundle/GUID-487B2E69-BB19-42CB-AC38-7EF18C0FE3AE/page/GUID-61AC454A-C6DD-46AD-8...