From: Zach Pfeffer <zpfeffer@codeaurora.org>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: linux@arm.linux.org.uk, ebiederm@xmission.com,
linux-arch@vger.kernel.org, dwalker@codeaurora.org,
mel@csn.ul.ie, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
andi@firstfloor.org, linux-omap@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 1/3 v3] mm: iommu: An API to unify IOMMU, CPU and device memory management
Date: Wed, 14 Jul 2010 13:11:49 -0700 [thread overview]
Message-ID: <20100714201149.GA14008@codeaurora.org> (raw)
In-Reply-To: <20100714104353B.fujita.tomonori@lab.ntt.co.jp>
On Wed, Jul 14, 2010 at 10:59:38AM +0900, FUJITA Tomonori wrote:
> On Tue, 13 Jul 2010 05:14:21 -0700
> Zach Pfeffer <zpfeffer@codeaurora.org> wrote:
>
> > > You mean that you want to specify this alignment attribute every time
> > > you create an IOMMU mapping? Then you can set segment_boundary_mask
> > > every time you create an IOMMU mapping. It's odd but it should work.
> >
> > Kinda. I want to forget about IOMMUs, devices and CPUs. I just want to
> > create a mapping that has the alignment I specify, regardless of the
> > mapper. The mapping is created on a VCM and the VCM is associated with
> > a mapper: a CPU, an IOMMU'd device or a direct mapped device.
>
> Sounds like you can do the above with the combination of the current
> APIs, create a virtual address and then an I/O address.
>
Yes, and that's what the implementation does - and all the other
implementations that need to do this same thing. Why not solve the
problem once?
> The above can't be a reason to add a new infrastructure includes more
> than 3,000 lines.
Right now its 3000 lines because I haven't converted to a function
pointer based implementation. Once I do that the size of the
implementation will shrink and the code will act as a lib. Users pass
buffer mappers and the lib will ease the management of of those
buffers.
>
>
> > > Another possible solution is extending struct dma_attrs. We could add
> > > the alignment attribute to it.
> >
> > That may be useful, but in the current DMA-API may be seen as
> > redundant info.
>
> If there is real requirement, we can extend the DMA-API.
If the DMA-API contained functions to allocate virtual space separate
from physical space and reworked how chained buffers functioned it
would probably work - but then things start to look like the VCM API
which does graph based map management.
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-07-14 20:11 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-03 5:38 [RFC 1/3 v3] mm: iommu: An API to unify IOMMU, CPU and device memory management Zach Pfeffer
2010-07-03 19:06 ` Eric W. Biederman
2010-07-07 22:44 ` Zach Pfeffer
2010-07-07 23:07 ` Russell King - ARM Linux
2010-07-08 23:59 ` Zach Pfeffer
2010-07-12 1:25 ` FUJITA Tomonori
2010-07-13 5:57 ` Zach Pfeffer
2010-07-13 6:03 ` FUJITA Tomonori
2010-07-13 12:14 ` Zach Pfeffer
2010-07-14 1:59 ` FUJITA Tomonori
2010-07-14 20:11 ` Zach Pfeffer [this message]
2010-07-14 22:05 ` Russell King - ARM Linux
2010-07-15 1:29 ` Zach Pfeffer
2010-07-15 1:47 ` Eric W. Biederman
2010-07-15 5:40 ` Zach Pfeffer
2010-07-15 5:35 ` Zach Pfeffer
2010-07-15 8:55 ` Russell King - ARM Linux
2010-07-16 0:48 ` Tim HRM
2010-07-16 7:58 ` Russell King - ARM Linux
2010-07-17 0:01 ` Larry Bassel
2010-07-19 9:21 ` Tim HRM
2010-07-21 0:44 ` Zach Pfeffer
2010-07-21 1:44 ` Timothy Meade
2010-07-22 4:06 ` Zach Pfeffer
2010-07-19 17:55 ` Michael Bohan
2010-07-19 18:40 ` Russell King - ARM Linux
2010-07-20 22:02 ` stepanm
2010-07-20 22:29 ` Russell King - ARM Linux
2010-07-21 5:49 ` Shilimkar, Santosh
2010-07-21 7:28 ` Russell King - ARM Linux
2010-07-21 7:45 ` Shilimkar, Santosh
2010-07-21 18:04 ` stepanm
2010-07-20 20:45 ` Zach Pfeffer
2010-07-20 20:54 ` Russell King - ARM Linux
2010-07-20 21:56 ` Zach Pfeffer
2010-07-19 6:52 ` Zach Pfeffer
2010-07-19 7:44 ` Eric W. Biederman
2010-07-22 4:25 ` Zach Pfeffer
2010-07-22 7:34 ` Russell King - ARM Linux
2010-07-22 16:25 ` Zach Pfeffer
2010-07-14 23:07 ` FUJITA Tomonori
2010-07-15 1:41 ` Zach Pfeffer
2010-07-19 8:22 ` Russell King - ARM Linux
2010-07-20 10:09 ` FUJITA Tomonori
2010-07-20 22:20 ` Zach Pfeffer
2010-07-21 1:44 ` FUJITA Tomonori
2010-07-22 4:30 ` Zach Pfeffer
2010-07-22 4:43 ` FUJITA Tomonori
2010-07-22 16:44 ` Zach Pfeffer
2010-07-22 7:39 ` Russell King - ARM Linux
2010-07-22 16:28 ` Zach Pfeffer
-- strict thread matches above, loose matches on Subject: below --
2010-07-06 15:42 Zach Pfeffer
2010-07-21 5:18 stepanm
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=20100714201149.GA14008@codeaurora.org \
--to=zpfeffer@codeaurora.org \
--cc=andi@firstfloor.org \
--cc=dwalker@codeaurora.org \
--cc=ebiederm@xmission.com \
--cc=fujita.tomonori@lab.ntt.co.jp \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-omap@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=mel@csn.ul.ie \
/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).