[PATCHv7 0/6] dmaengine: rcar-dmac: add iommu support for slave transfers

Vinod Koul vinod.koul at intel.com
Wed Jun 1 11:06:11 PDT 2016


On Wed, Jun 01, 2016 at 05:22:23PM +0200, Niklas Söderlund wrote:
> Hi,
> 
> [In this v7 series I have tried to address the questions raised by Christoph 
> Hellwig and I hope it can awnser your concernes regarding dma-debug.]
> 
> This series tries to solve the problem with DMA with device registers
> (MMIO registers) that are behind an IOMMU for the rcar-dmac driver. A
> recent patch '9575632 (dmaengine: make slave address physical)'
> clarifies that DMA slave address provided by clients is the physical
> address. This puts the task of mapping the DMA slave address from a
> phys_addr_t to a dma_addr_t on the DMA engine.
> 
> Without an IOMMU this is easy since the phys_addr_t and dma_addr_t are
> the same and no special care is needed. However if you have a IOMMU you
> need to map the DMA slave phys_addr_t to a dma_addr_t using something
> like this.
> 
> This series is based on top of v4.7-rc1.

The dmanegine bits looks okay to me. Btw how is the merge planned for this?
Do you wnat this to be merged thru dmaengine tree or something else?

-- 
~Vinod



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