From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: [LINUX] dma: Use swiotlb mask for coherent
	mappings too
Date: Wed, 20 Dec 2006 13:36:11 +0000
Message-ID: <C1AEECCB.6A3E%keir@xensource.com>
References: <45893CB8.76E4.0078.0@novell.com>
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To: Jan Beulich <jbeulich@novell.com>, Keir Fraser <keir@xensource.com>
Cc: Xen Development Mailing List <xen-devel@lists.xensource.com>, Herbert Xu <herbert@gondor.apana.org.au>, Calvin Webster <cwebster@ec.rr.com>
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On 20/12/06 12:38, "Jan Beulich" <jbeulich@novell.com> wrote:

>>>> Keir Fraser <keir@xensource.com> 20.12.06 12:55 >>>
>> We could fall back to swiotlb_alloc/free_coherent?
> 
> Hmm, that would mean extra tracking, as dma_free_coherent must have a way
> to tell whether to call xen_destroy_contiguous_region directly or invoke
> swiotlb_free_coherent (and I wouldn't want to make io_tlb_{start,end} global).

dma_alloc_coherent is used to allocate some rather big areas in some cases
(e.g., when uploading firmware) which I'm sure would not fit in the
swiotlb's 64kB contiguous allocations. Some kind of is-within-aperture query
function would seem a reasonable addition to the swiotlb API.

 -- Keir