joanxie the problem with iMX6 SoloX SDK is that it doesn't contain reference implementation of SAI and SDMA driver. I was hoping that these drivers were implemented in the SDK but they are not.
I only found the SAI and SDMA drivers for iMX6 family in iMX6UL SDK. If these drivers are present in any iMX6 SoloX SDK, can you please point me to that? I did check the FreeRTOS IMX6SX BSP you provided above and it doesn't have these drivers either.