Re: [PATCH v2 1/2] of/pci: add of_pci_dma_configure() update dma configuration

[Murali Karicheri]

On 01/06/2015 02:50 PM, Will Deacon wrote:
> On Fri, Jan 02, 2015 at 10:33:53PM +0000, Murali Karicheri wrote:
> > On 01/02/2015 03:45 PM, Rob Herring wrote:
> > > On Fri, Jan 2, 2015 at 11:20 AM, Murali Karicheri<m-karicheri2@xxxxxx>   wrote:
> > > > On 12/26/2014 02:33 PM, Rob Herring wrote:
> > > > > On Wed, Dec 24, 2014 at 4:11 PM, Murali Karicheri<m-karicheri2@xxxxxx>
> > > > > > +               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
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