From: Marek Szyprowski <m.szyprowski@samsung.com>
To: 'Stephen Rothwell' <sfr@canb.auug.org.au>
Cc: linux-arm-kernel@lists.infradead.org,
linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org,
linux-arch@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
iommu@lists.linux-foundation.org,
'Kyungmin Park' <kyungmin.park@samsung.com>,
'Arnd Bergmann' <arnd@arndb.de>, 'Joerg Roedel' <joro@8bytes.org>,
'Russell King - ARM Linux' <linux@arm.linux.org.uk>,
'Shariq Hasnain' <shariq.hasnain@linaro.org>,
'Chunsang Jeong' <chunsang.jeong@linaro.org>,
'Krishna Reddy' <vdumpa@nvidia.com>,
'KyongHo Cho' <pullip.cho@samsung.com>,
Andrzej Pietrasiewicz <andrzej.p@samsung.com>,
'Benjamin Herrenschmidt' <benh@kernel.crashing.org>
Subject: RE: [PATCH 6/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs
Date: Wed, 14 Dec 2011 13:37:07 +0100 [thread overview]
Message-ID: <040501ccba5d$1821e0a0$4865a1e0$%szyprowski@samsung.com> (raw)
In-Reply-To: <20111212094559.e4af7c0ab6633de400487fde@canb.auug.org.au>
Hello,
On Sunday, December 11, 2011 11:46 PM Stephen Rothwell wrote:
> On Fri, 09 Dec 2011 17:39:56 +0100 Marek Szyprowski <m.szyprowski@samsung.com> wrote:
> >
> > Introduce new alloc/free/mmap methods that take attributes argument.
> > alloc/free_coherent can be implemented on top of the new alloc/free
> > calls with NULL attributes. dma_alloc_non_coherent can be implemented
> > using DMA_ATTR_NONCOHERENT attribute, dma_alloc_writecombine can also
> > use separate DMA_ATTR_WRITECOMBINE attribute. This way the drivers will
> > get more generic, platform independent way of allocating dma memory
> > buffers with specific parameters.
> >
> > One more attribute can be usefull: DMA_ATTR_NOKERNELVADDR. Buffers with
> > such attribute will not have valid kernel virtual address. They might be
> > usefull for drivers that only exports the DMA buffers to userspace (like
> > for example V4L2 or ALSA).
> >
> > mmap method is introduced to let the drivers create a user space mapping
> > for a DMA buffer in generic, architecture independent way.
> >
> > TODO: update all dma_map_ops clients for all architectures
>
> To give everyone some chance, you should come up with a transition plan
> rather than this "attempt to fix everyone at once" approach. You could
> (for example) just add the new methods now and only remove them in the
> following merge window when all the architectures have had a chance to
> migrate.
>
> And, in fact, (as I presume you know) this patch just breaks everyone
> with no attempt to cope.
Yes, I know that. Next version will include correct fix for this issue as
well as adjustments for other architectures. I was asked to post a current
version of DMA-mapping & IOMMU integration patch rebased on the latest kernel
and I wanted to this before going for holidays to let others to work with the
latest version.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
next prev parent reply other threads:[~2011-12-14 12:37 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-09 16:39 [PATCH 0/8 v4] ARM: DMA-mapping framework redesign Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-09 16:39 ` [PATCH 1/8] ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-09 16:39 ` [PATCH 2/8] ARM: dma-mapping: use asm-generic/dma-mapping-common.h Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-09 16:39 ` [PATCH 3/8] ARM: dma-mapping: implement dma sg methods on top of any generic dma ops Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-09 16:39 ` [PATCH 4/8] ARM: dma-mapping: move all dma bounce code to separate dma ops structure Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-09 16:39 ` [PATCH 5/8] ARM: dma-mapping: remove redundant code and cleanup Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-09 16:39 ` [PATCH 6/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2011-12-11 22:45 ` Stephen Rothwell
2011-12-11 22:45 ` Stephen Rothwell
2011-12-14 12:37 ` Marek Szyprowski [this message]
2011-12-09 16:39 ` [PATCH 7/8] ARM: dma-mapping: use alloc, mmap, free from dma_ops Marek Szyprowski
2011-12-09 16:39 ` [PATCH 8/8] ARM: dma-mapping: add support for IOMMU mapper Marek Szyprowski
2011-12-09 16:39 ` Marek Szyprowski
2012-01-09 15:49 ` [PATCH 8/8 RESEND] " Marek Szyprowski
2012-01-09 15:49 ` Marek Szyprowski
2012-01-25 12:59 ` Russell King - ARM Linux
2012-01-25 12:59 ` Russell King - ARM Linux
2012-01-26 8:09 ` Marek Szyprowski
2012-01-25 12:47 ` [PATCH 8/8] " Hiroshi Doyu
2012-01-25 12:47 ` Hiroshi Doyu
2012-01-26 7:46 ` Marek Szyprowski
2012-01-26 7:46 ` Marek Szyprowski
2012-01-10 8:42 ` [PATCH 0/8 v4] ARM: DMA-mapping framework redesign Marek Szyprowski
-- strict thread matches above, loose matches on Subject: below --
2011-10-18 17:19 [PATCH 0/8 v3] " Marek Szyprowski
2011-10-18 17:19 ` [PATCH 6/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs Marek Szyprowski
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