[PATCHv3 net-next 21/22] net: mvpp2: set dma mask and coherent dma mask on PPv2.2

David Laight David.Laight at ACULAB.COM
Tue Mar 7 09:24:21 PST 2017

From: Thomas Petazzoni
> Sent: 07 March 2017 15:53
> On PPv2.2, the streaming mappings can be anywhere in the first 40 bits
> of the physical address space. However, for the coherent mappings, we
> still need them to be in the first 32 bits of the address space,
> because all BM pools share a single register to store the high 32 bits
> of the BM pool address, which means all BM pools must be allocated in
> the same 4GB memory area.

Are the coherent mappings just used for ring structures?
If it might be reasonable to allocate them as a single entity,
thus guaranteeing they all reside in a single 4G region.


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