Re: [PATCH v3 0/3] DaVinci DMA engine conversion

From: Daniel Mack <zonque@gmail.com>
To: Matt Porter <mporter@ti.com>
Cc: vinod.koul@intel.com, cjb@laptop.org, grant.likely@secretlab.ca,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux ARM Kernel List <linux-arm-kernel@lists.infradead.org>,
	Linux MMC List <linux-mmc@vger.kernel.org>,
	Linux SPI Devel List  <spi-devel-general@lists.sourceforge.net>,
	Linux DaVinci Kernel List 
	<davinci-linux-open-source@linux.davincidsp.com>,
	Sekhar Nori <nsekhar@ti.com>
Subject: Re: [PATCH v3 0/3] DaVinci DMA engine conversion
Date: Mon, 27 Aug 2012 17:33:19 +0200	[thread overview]
Message-ID: <503B933F.2030803@gmail.com> (raw)
In-Reply-To: <1345684176-21472-1-git-send-email-mporter@ti.com>

Hi Matt,

On 23.08.2012 03:09, Matt Porter wrote:
> This series begins the conversion of the DaVinci private EDMA API
> implementation to a DMA engine driver and converts two of the three
> in-kernel users of the private EDMA API to DMA engine.
> 
> The approach taken is similar to the recent OMAP DMA Engine
> conversion. The EDMA DMA Engine driver is a wrapper around the existing
> private EDMA implementation and registers the platform device within
> the driver.  This allows the conversion series to stand alone with just
> the drivers and no changes to platform code. It also allows peripheral
> drivers to continue to use the private EDMA implementation until they
> are converted.
> 
> The EDMA DMA Engine driver supports slave transfers only at this time. It
> is planned to add cyclic transfers in support of audio peripherals.
> 
> There are three users of the private EDMA API in the kernel now:
> davinci_mmc, spi-davinci, and davinci-mcasp.  This series provides DMA
> Engine conversions for the davinci_mmc and spi-davinci drivers which
> use the supported slave transfers.
> 
> This series has been tested on an AM18x EVM and Hawkboard with
> driver performance comparable to that of the private EDMA API
> implementations. Both MMC0 and MMC1 are tested which handles the
> DA850/OMAP-L138/AM18x specific case where MMC1 uses DMA channels on
> a second EDMA channel controller.  All other platforms have a simpler
> design with just a single EDMA channel controller.
> 
> For those wanting to easily test this series, I've pushed a branch for
> each version to my github tree at https://github.com/ohporter/linux. The
> current branch is edma-dmaengine-v3.
> 
> After this series, the current plan is to complete the mcasp driver
> conversion which includes adding cyclic dma support. This will then
> enable the removal and refactoring of the private EDMA API functionality
> into the EDMA DMA Engine driver.  Since EDMA is also used on the AM33xx
> family of parts in mach-omap2/, the plan is to enable this driver on
> that platform as well.

Once you have a patch for the McASP driver conversion, I can happily
test this on a AM33xx board, together with Gururaja's latest McASP
refactoring series. Let me know how I can help you here.

Thanks,
Daniel