On 01/06/2015 02:50 PM, Will Deacon wrote:

On Fri, Jan 02, 2015 at 10:33:53PM +0000, Murali Karicheri wrote:

quoted

On 01/02/2015 03:45 PM, Rob Herring wrote:

quoted

On Fri, Jan 2, 2015 at 11:20 AM, Murali Karicheri[off-list ref]   wrote:

quoted

On 12/26/2014 02:33 PM, Rob Herring wrote:

quoted

On Wed, Dec 24, 2014 at 4:11 PM, Murali Karicheri[off-list ref]

quoted

+               coherent = of_dma_is_coherent(parent_np);
+               dev_dbg(dev, "device is%sdma coherent\n",
+                       coherent ? " " : " not ");
+
+               arch_setup_dma_ops(dev, dma_addr, size, NULL, coherent);

This is the same code as of_dma_configure. The only difference I see
is which node ptr is passed to of_dma_get_range. You need to make that
a function param of of_dma_configure.

of_dma_configure also has iommu handling now. You will probably need
something similar for PCI in that you setup an iommu based on the root
bus DT properties.

Initially I had the same idea to re-use the existing function
of_dma_configure() for this. I wanted to defer this until we have an
agreement on the changes required for the subject functionality. My quick
review of the code suggestio this would require additional API changes as
below. I did a quick test of the changes and it works for Keystone, but need
to be reviewed by everyone as I touch the IOMMU functionality here and I
don't have a platform with IOMMU. Need test by someone to make sure I don't
break anything.

The IOMMU changes look trivial. We may want to address the comment in
of_iommu_configure about parent nodes. We should be sure these changes
work with how we would do searching parent nodes.

I have no experience with IOMMU and may not offer much help here as I
originally wrote above. Will Deacon has added this API and probably able
to offer some help in this discussion.

Will Deacon,

Any comment?

Sorry for the delay; I'm still catching up on email after the Christmas
break, but I *will* get around to looking at this. If you have a new version
to post based on the comments from Rob and Arnd, feel free to send that and
I'll look at that instead.

Will

Will,

I will be posting v3 of the patch tomorrow and you can review that.

Regards,

Murali


-- 
Murali Karicheri
Linux Kernel, Texas Instruments