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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Joerg Roedel <joerg.roedel@amd.com>
Subject: Re: [PATCH 2/5] iommu/amd: Implement DOMAIN_ATTR_GEOMETRY attribute
Date: Thu, 19 Jan 2012 17:27:09 +0100
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Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        "Ohad Ben-Cohen" <ohad@wizery.com>,
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        Hiroshi Doyu <hdoyu@nvidia.com>
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Hi Joerg,

On Thursday 19 January 2012 17:07:39 Joerg Roedel wrote:
> On Thu, Jan 19, 2012 at 04:46:13PM +0100, Laurent Pinchart wrote:
> > > +struct iommu_domain_geometry {
> > > +	u64 aperture_start;	/* First address that can be mapped    */
> > > +	u64 aperture_end;	/* Last address that can be mapped     */
> > 
> > Would it make sense to use a platform-dependent type that represents
> > physical addresses instead of u64 ?
> 
> Well, u64 is a catch-all datatype which should suit all drivers. Is this
> a problem at ARM?

No, it's not a problem for ARM, at least to my knowledge. It just struck me as 
weird, as we have specific data types for other kinds of addresses (such as 
dma_addr_t).

> We can also go the more complicated way of introducing an iova_addr_t or
> something. But if possible I would like to avoid that.
> 
> > > @@ -62,7 +70,8 @@ enum iommu_attr {
> > > 
> > >   * @unmap: unmap a physically contiguous memory region from an iommu
> > > 
> > > domain * @iova_to_phys: translate iova to physical address
> > > 
> > >   * @domain_has_cap: domain capabilities query
> > > 
> > > - * @commit: commit iommu domain
> > > + * @domain_get_attr: Query domain attributes
> > > + * @domain_set_attr: Change domain attributes
> > 
> > This belongs to the previous patch.
> 
> Right, I change that.

-- 
Regards,

Laurent Pinchart