linux-kernel - Re: [PATCH 1/5] dmaengine: add ep93xx DMA support

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Date:	Wed, 25 May 2011 11:09:26 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	"Koul, Vinod" <vinod.koul@...el.com>
Cc:	Mika Westerberg <mika.westerberg@....fi>,
	linux-kernel@...r.kernel.org,
	Grant Likely <grant.likely@...retlab.ca>,
	hsweeten@...ionengravers.com, ryan@...ewatersys.com,
	Dan Williams <dan.j.williams@...el.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 1/5] dmaengine: add ep93xx DMA support

2011/5/25 Koul, Vinod <vinod.koul@...el.com>:
> On Wed, 2011-05-25 at 10:39 +0200, Linus Walleij wrote:
>> 2011/5/22 Mika Westerberg <mika.westerberg@....fi>:
>>
>> > The ep93xx DMA controller has 10 independent memory to peripheral (M2P)
>> > channels, and 2 dedicated memory to memory (M2M) channels. M2M channels can
>> > also be used by SPI and IDE to perform DMA transfers to/from their memory
>> > mapped FIFOs.
>>
>> No so much a review comment as an observation: I opposed the merge of the
>> EP93xx SPI driver in drivers/spi/ep93xx_spi.c on the grounds that it was close
>> enough to amba-pl022.c that it could use that driver instead.
>>
>> One of the arguments against was that you were going to do custom DMA
>> and stuff. Now you're using the DMAengine, so can you please reconsider
>> refactoring amba-pl022.c to suit your needs and you'll get DMA support for
>> free mor or less.
>
> Linus is the dma IP same as existing ones?
> In that case we shouldn't have a new driver for same IP.

Nope, not as far as I can tell. The fear of this IP being an amba-pl08x.c
already hit med so I checked the register map, but it appears to be unique.
I haven't compared it to amba-pl330.c though.

Yours,
Linus Walleij
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