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