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SubjectRe: [PATCH 1/7] x86: add alloc_coherent dma_ops callback to GART driver
On Wed, Aug 13, 2008 at 09:45:54AM +0900, FUJITA Tomonori wrote:
> On Tue, 12 Aug 2008 17:24:11 +0200
> Joerg Roedel <joerg.roedel@amd.com> wrote:
>
> > Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
> > ---
> > arch/x86/kernel/pci-gart_64.c | 21 +++++++++++++++++++++
> > 1 files changed, 21 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
> > index cdab678..55cc388 100644
> > --- a/arch/x86/kernel/pci-gart_64.c
> > +++ b/arch/x86/kernel/pci-gart_64.c
> > @@ -499,6 +499,26 @@ error:
> > return 0;
> > }
> >
> > +/* allocate and map a coherent mapping */
> > +static void *
> > +gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
> > + gfp_t flag)
> > +{
> > + void *vaddr;
> > +
> > + vaddr = (void *)__get_free_pages(flag, get_order(size));
> > + if (!vaddr)
> > + return NULL;
> > +
> > + *dma_addr = gart_map_single(dev, __pa(vaddr), size, DMA_BIDIRECTIONAL);
> > + if (*dma_addr != bad_dma_address)
> > + return vaddr;
> > +
> > + free_pages((unsigned long)vaddr, get_order(size));
> > +
> > + return NULL;
> > +}
> > +
> > static int no_agp;
>
> It would be better to return a size-aligned memory as DMA-mapping.txt
> says (though I don't think that it doesn't matter much):
>
> http://lkml.org/lkml/2008/8/8/555

Agreed. I try to change the patchset so it returns size aligned dma
addresses.

> I also think that x86 IOMMUs need to handle DMA_*BIT_MASK properly,
> don't we?

Shouldn't this be done by the IOMMUs using your iommu_area_alloc()
function? Or do I misunderstand something?

Joerg

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