Date: Thu, 21 Aug 2008 17:17:24 +0200
From: Joerg Roedel <joerg.roedel@amd.com>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
CC: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com,
       linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
       muli@il.ibm.com
Subject: Re: [PATCH 1/8] x86: add alloc_coherent dma_ops callback to GART driver
Message-ID: <20080821151724.GB3189@amd.com>
References: <1219156366-32498-1-git-send-email-joerg.roedel@amd.com> <1219156366-32498-2-git-send-email-joerg.roedel@amd.com> <20080821225038E.fujita.tomonori@lab.ntt.co.jp>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20080821225038E.fujita.tomonori@lab.ntt.co.jp>
User-Agent: mutt-ng/devel-r804 (Linux)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1987
Lines: 53

On Thu, Aug 21, 2008 at 11:16:49PM +0900, FUJITA Tomonori wrote:
> On Tue, 19 Aug 2008 16:32:39 +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 4d8efb0..44a75a6 100644
> > --- a/arch/x86/kernel/pci-gart_64.c
> > +++ b/arch/x86/kernel/pci-gart_64.c
> > @@ -506,6 +506,26 @@ 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;
> 
> I'm not sure a rule is documented or not, but I think that IOMMUs
> return zeroed memory wrt dma_alloc_coherent. The current pci-dma.c
> does, so I think that it would be better to keep the current behavior.

Ok, true. I will send and update patch to add this. Thanks.

Joerg

-- 
           |           AMD Saxony Limited Liability Company & Co. KG
 Operating |         Wilschdorfer Landstr. 101, 01109 Dresden, Germany
 System    |                  Register Court Dresden: HRA 4896
 Research  |              General Partner authorized to represent:
 Center    |             AMD Saxony LLC (Wilmington, Delaware, US)
           | General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, Thomas McCoy

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/