[PATCHv9 0/6] dmaengine: rcar-dmac: add iommu support for slave transfers

Vinod Koul vinod.koul at intel.com
Thu Sep 15 09:26:51 PDT 2016

On Wed, Aug 10, 2016 at 11:07:10PM +0530, Vinod Koul wrote:
> On Wed, Aug 10, 2016 at 01:22:13PM +0200, Niklas Söderlund wrote:
> > Hi,
> > 
> > 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 v4.8-rc1. And I'm hoping to be able to collect a
> > Ack from Russell King on patch 4/6 that adds the ARM specific part and then be
> > able to take the whole series through the dmaengine tree. If this is not the
> > best route I'm more then happy to do it another way.
> > 
> > It's tested on a Koelsch with CONFIG_IPMMU_VMSA and by enabling the
> > ipmmu_ds node in r8a7791.dtsi. I verified operation by interacting with
> > /dev/mmcblk1, i2c and the serial console which are devices behind the
> > iommu.
> As I said in last one, the dmaengine parts look fine to me. But to go thru
> dmaengine tree I would need ACK on non dmaengine patches.

I havent heard back from this one and I am inclined to merge this one now.
If anyone has any objects, please speak up now...

Also ACKs welcome...


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