[PATCH 03/10] x86: add initialization code for DMA-API debugging
FUJITA Tomonori
fujita.tomonori at lab.ntt.co.jp
Sat Nov 22 02:16:05 PST 2008
On Sat, 22 Nov 2008 10:40:32 +0100
Joerg Roedel <joro at 8bytes.org> wrote:
> > > +static int hash_fn(struct dma_debug_entry *entry)
> > > +{
> > > + /*
> > > + * Hash function is based on the dma address.
> > > + * We use bits 20-27 here as the index into the hash
> > > + */
> > > + BUG_ON(entry->dev_addr == bad_dma_address);
> >
> > 'bad_dma_address' is x86 specific. You already found it though.
>
> Interesting. Is there another value for dma_addr_t which drivers can
> check for to find out if a dma-api operation failed?
They are architecture dependent. But only X86 uses a variable because
of GART and swiotlb, I think.
More information about the iommu
mailing list