From: Dave Gordon <david.s.gordon@intel.com>
To: Boris Brezillon <boris.brezillon@free-electrons.com>,
Mark Brown <broonie@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>,
Brian Norris <computersforpeace@gmail.com>,
linux-mtd@lists.infradead.org,
Andrew Morton <akpm@linux-foundation.org>,
linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
Maxime Ripard <maxime.ripard@free-electrons.com>,
Chen-Yu Tsai <wens@csie.org>,
linux-sunxi@googlegroups.com, Vinod Koul <vinod.koul@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
dmaengine@vger.kernel.org,
Mauro Carvalho Chehab <m.chehab@samsung.com>,
Hans Verkuil <hans.verkuil@cisco.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
linux-media@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
devicetree@vger.kernel.org, Richard Weinberger <richard@nod.at>
Subject: Re: [PATCH v2 4/7] scatterlist: add sg_alloc_table_from_buf() helper
Date: Tue, 5 Apr 2016 08:11:48 +0100 [thread overview]
Message-ID: <57036534.7010800@intel.com> (raw)
In-Reply-To: <20160330201831.38e1d6bd@bbrezillon>
On 30/03/16 19:18, Boris Brezillon wrote:
> On Wed, 30 Mar 2016 09:51:43 -0700
> Mark Brown <broonie@kernel.org> wrote:
>
>> On Wed, Mar 30, 2016 at 05:39:51PM +0200, Boris Brezillon wrote:
>>> sg_alloc_table_from_buf() provides an easy solution to create an sg_table
>>> from a virtual address pointer. This function takes care of dealing with
>>> vmallocated buffers, buffer alignment, or DMA engine limitations (maximum
>>> DMA transfer size).
>>
>> This seems nice. Should we also have a further helper on top of this
>> which will get constraints from a dmaengine, it seems like it'd be a
>> common need?
>
> Yep, we could create a wrapper extracting dma_slave caps info,
> converting it to sg_constraints and calling sg_alloc_table_from_buf().
> But let's try to get this function accepted first, and I'll send another
> patch providing this wrapper.
>
> BTW, do you see other things that should be added in sg_constraints?
>
You could compare with the things Solaris uses to describe the
restrictions on a DMA binding ...
http://docs.oracle.com/cd/E23824_01/html/821-1478/ddi-dma-attr-9s.html#REFMAN9Sddi-dma-attr-9s
.Dave.
next prev parent reply other threads:[~2016-04-05 7:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-30 15:39 [PATCH v2 0/7] mtd: nand: sunxi: add support for DMA operations Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 1/7] mtd: nand: sunxi: move some ECC related operations to their own functions Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 2/7] mtd: nand: sunxi: make OOB retrieval optional Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 3/7] mtd: nand: sunxi: make cur_off parameter optional in extra oob helpers Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 4/7] scatterlist: add sg_alloc_table_from_buf() helper Boris Brezillon
2016-03-30 16:51 ` Mark Brown
2016-03-30 18:18 ` Boris Brezillon
2016-03-30 18:34 ` Mark Brown
2016-04-05 7:11 ` Dave Gordon [this message]
2016-03-31 4:56 ` [v2,4/7] " Vignesh R
2016-03-31 7:26 ` Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 5/7] mtd: provide helper to prepare buffers for DMA operations Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 6/7] mtd: nand: sunxi: add support for DMA assisted operations Boris Brezillon
2016-03-30 15:39 ` [PATCH v2 7/7] mtd: nand: sunxi: update DT bindings Boris Brezillon
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