From: Kumar Gala <galak@kernel.crashing.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
hch@infradead.org, linux-kernel@vger.kernel.org, mingo@elte.hu,
ian.campbell@citrix.com, beckyb@kernel.crashing.org
Subject: Re: [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping
Date: Wed, 8 Apr 2009 23:43:27 -0500 [thread overview]
Message-ID: <25E78C44-E366-40D1-AC1B-3022F1A95069@kernel.crashing.org> (raw)
In-Reply-To: <49DD3C9C.7060101@goop.org>
On Apr 8, 2009, at 7:09 PM, Jeremy Fitzhardinge wrote:
> FUJITA Tomonori wrote:
>> On Wed, 08 Apr 2009 16:16:17 -0700
>> Jeremy Fitzhardinge <jeremy@goop.org> wrote:
>>
>>
>>> FUJITA Tomonori wrote:
>>>
>>>>> Becky's patches of last week also added __weak annotations to
>>>>> swiotlb_bus_to_virt, virt_to_bus and bus_to_phys; added the
>>>>> hwdev parameter to swiotlb_bus_to_phys; and added a weak
>>>>> swiotlb_arch_address_needs_mapping. I assume that was needed
>>>>> because powerpc needs non-trivial implementations for those
>>>>> functions.
>>>>>
>>>> Hmm, what she added are wrappers of virt_to_bus and bus_to_virt. We
>>>> can remove these and directly use virt_to_bus and bus_to_virt.
>>>>
>>> In general those interfaces are deprecated. Are we un-deprecating
>>> them? Or do you mean adding virt<->bus to dma_ops?
>>>
>>
>> Hmm, these interfaces are wrong for drivers surely because they can't
>> handle dma mapping properly. However, they are exactly what swiotlb
>> needs (swiotlb doesn't need to care about dma mapping).
>
> It needs to care about the mapping from phys to bus. On x86 they're
> identical, but on powerpc there can be at least an offset between
> them.
>
>> Until 2.6.28,
>> swiotlb has used them. They are with IA64, X86_64 and PPC_32, I
>> think.
>>
>
> Well, Becky's patches also added the hwdev argument to them, so
> presumably the powerpc implementation needs that (different devices/
> buses have differing views of physical memory, I guess).
On powerpc we need the hwdev because things vary based on bus. For
our SoC chips we don't need any mapping between phys & bus. However
something like PCI does have a mapping (a simple offset).
- k
next prev parent reply other threads:[~2009-04-09 4:45 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-08 14:09 [PATCH V3 0/7] swiotlb: changes for powerpc/highmem Kumar Gala
2009-04-08 14:09 ` [PATCH 1/7] swiotlb: comment corrections (no code changes) Kumar Gala
2009-04-08 14:09 ` [PATCH 2/7] swiotlb: fix compile warning Kumar Gala
2009-04-08 14:09 ` [PATCH 3/7] swiotlb: map_page fix for highmem systems Kumar Gala
2009-04-08 14:09 ` [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping Kumar Gala
2009-04-08 14:09 ` [PATCH 5/7] swiotlb: Rename unmap_single to do_unmap_single Kumar Gala
2009-04-08 14:09 ` [PATCH 6/7] swiotlb: Use swiotlb_sync_single instead of duplicating code Kumar Gala
2009-04-08 14:09 ` [PATCH 7/7] swiotlb: Change swiotlb_bus_to[phys,virt] prototypes Kumar Gala
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: change " Becky Bruce
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: use swiotlb_sync_single instead of duplicating code Becky Bruce
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: rename unmap_single to do_unmap_single Becky Bruce
2009-04-08 15:25 ` [tip:core/iommu] swiotlb: allow arch override of address_needs_mapping Becky Bruce
2009-04-08 20:38 ` [PATCH 4/7] swiotlb: Allow " Christoph Hellwig
2009-04-08 20:56 ` Kumar Gala
2009-04-08 21:15 ` FUJITA Tomonori
2009-04-08 21:55 ` Jeremy Fitzhardinge
2009-04-08 22:10 ` FUJITA Tomonori
2009-04-08 22:36 ` Jeremy Fitzhardinge
2009-04-08 23:01 ` FUJITA Tomonori
2009-04-08 23:16 ` Jeremy Fitzhardinge
2009-04-08 23:37 ` FUJITA Tomonori
2009-04-09 0:09 ` Jeremy Fitzhardinge
2009-04-09 4:43 ` Kumar Gala [this message]
2009-04-09 18:34 ` FUJITA Tomonori
2009-04-09 19:19 ` Jeremy Fitzhardinge
2009-04-09 19:43 ` FUJITA Tomonori
2009-04-09 19:50 ` FUJITA Tomonori
2009-04-09 19:54 ` Jeremy Fitzhardinge
2009-04-09 4:59 ` Kumar Gala
2009-04-09 18:50 ` FUJITA Tomonori
2009-04-09 20:10 ` Kumar Gala
2009-04-09 20:25 ` Kumar Gala
2009-04-08 22:24 ` Christoph Hellwig
2009-04-08 15:24 ` [tip:core/iommu] swiotlb: map_page fix for highmem systems Becky Bruce
2009-04-08 15:24 ` [tip:core/iommu] swiotlb: fix compile warning Becky Bruce
2009-04-08 15:24 ` [tip:core/iommu] swiotlb: comment corrections Becky Bruce
2009-04-08 14:21 ` [PATCH V3 0/7] swiotlb: changes for powerpc/highmem Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2009-04-04 1:56 [PATCH V2 " Becky Bruce
2009-04-04 1:56 ` [PATCH 1/7] swiotlb: comment corrections (no code changes) Becky Bruce
2009-04-04 1:56 ` [PATCH 2/7] swiotlb: fix compile warning Becky Bruce
2009-04-04 1:56 ` [PATCH 3/7] swiotlb: map_page fix for highmem systems Becky Bruce
2009-04-04 1:56 ` [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping Becky Bruce
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=25E78C44-E366-40D1-AC1B-3022F1A95069@kernel.crashing.org \
--to=galak@kernel.crashing.org \
--cc=beckyb@kernel.crashing.org \
--cc=fujita.tomonori@lab.ntt.co.jp \
--cc=hch@infradead.org \
--cc=ian.campbell@citrix.com \
--cc=jeremy@goop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).