Re: [PATCH v4 0/4] arm64: IOMMU-backed DMA mapping

[Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>]

Hi Joerg,

On 20/07/15 16:26, Joerg Roedel wrote:
> On Thu, Jul 16, 2015 at 07:40:11PM +0100, Robin Murphy wrote:
>>   arch/arm64/Kconfig                   |   1 +
>>   arch/arm64/include/asm/dma-mapping.h |  15 +-
>>   arch/arm64/mm/dma-mapping.c          | 452 +++++++++++++++++++++++++++++
>
> What happened to the plan to merge this with the existing iommu-based
> dma-api implementation for 32 bit ARM?

The issue currently is that there are a bunch of drivers using the 
exported arm_iommu_* functions directly. From what I can tell, they seem 
like they could probably all be converted to using default domains 
and/or the new domain type abstractions via the core IOMMU API, which 
would then allow killing off dma_iommu_mapping and rewriting the 
arch/arm implementation to use the new shared code. I don't currently 
have any 32-bit platform to test with, so I'm a little dubious of taking 
that all on myself right now.

In the meantime on arm64, DMA mapping ops are needed for SMMUv3 platform 
device support, the Mediatek M4U patches and my own SMMUv2 work, so it 
would be very useful to get the arm64 and common code in as a first 
step, then look at cleaning up arch/arm for 4.4 without dangling 
dependencies.

Robin.

>
>
> 	Joerg
>