Re: [PATCH 0/3] Apple M1 DART IOMMU driver

Sven Peter
2021-03-26T16:11:33Z

On Fri, Mar 26, 2021, at 16:59, Mark Kettenis wrote:
> Some of the DARTs provide a bypass facility. That code make using the
> standard "dma-ranges" property tricky. That property would need to
> contain the bypass address range. But that would mean that if the
> DART driver needs to look at that property to figure out the address
> range that supports translation it will need to be able to distinguish
> between the translatable address range and the bypass address range.

Do we understand if and why we even need to bypass certain streams?
And do you have an example for a node in the ADT that contains this bypass range?

I've only seen nodes with "bypass" and "bypass-adress" but that could just be
some software abstraction Apple uses which doesn't map well to Linux or other OSes
and might not even be required here.

Sven