On 06-01-21, 16:53, Rob Herring wrote:

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+  dma-channel-mask:
+    description:
+       For DMA capability, We will know the addressing capability of
+       MediaTek Command-Queue DMA controller through dma-channel-mask.
+      minimum: 1
+      maximum: 63

Indentation is wrong here so this has no effect.

I'll fix it

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A mask of 63 is 6 channels...

In my opinion, kernel dma mask if for 32/64 bit capability...
If I don't set dma mask I will get fail on DMATEST.

As in the kernel's 'dma_mask'? That's something entirely different.
The driver should set the mask to the max the device supports.
Typically this is a 32-bit or 64-bit mask. The default is 32-bit. If
the SoC has limitations in its buses, then you need to use
'dma-ranges' in DT which will in turn set the bus_dma_limit.

Correct, dma_mask tells dmatest the capability of the device and should
be set accordingly

dma-channel-mask defines the 'Bitmask of available DMA channels' and is
deined in dma-common.yaml

-- 
~Vinod