From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH v7 01/10] ARM: davinci: move private EDMA API to arm/common Date: Mon, 04 Feb 2013 21:22:42 +0300 Message-ID: <510FFC72.2050706@mvista.com> References: <20130201184915.GP2244@beef> <510C1D0E.6030401@mvista.com> <20130201185820.GE29898@arwen.pp.htv.fi> <510C2A47.1090607@mvista.com> <20130201205600.GA31762@arwen.pp.htv.fi> <20130201213003.GW2637@n2100.arm.linux.org.uk> <20130204154153.GA18237@arwen.pp.htv.fi> <510FF1A6.403@mvista.com> <20130204164712.GB4269@arwen.pp.htv.fi> <510FF5C9.3030600@mvista.com> <20130204170216.GC4269@arwen.pp.htv.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130204170216.GC4269@arwen.pp.htv.fi> Sender: linux-doc-owner@vger.kernel.org To: balbi@ti.com Cc: Russell King - ARM Linux , Matt Porter , Linux DaVinci Kernel List , Chris Ball , "Cousson, Benoit" , Arnd Bergmann , Linux Documentation List , Tony Lindgren , Devicetree Discuss , Mark Brown , Linux MMC List , Linux Kernel Mailing List , Rob Herring , Grant Likely , Vinod Koul , Rob Landley , Dan Williams , Linux SPI Devel List , Linux OMAP List , Linux ARM Kernel List List-Id: devicetree@vger.kernel.org Hello. On 02/04/2013 08:02 PM, Felipe Balbi wrote: >>> On Mon, Feb 04, 2013 at 08:36:38PM +0300, Sergei Shtylyov wrote: >>>>> opted out of it. From the top of my head we have CPPI 3.x, CPPI 4.1, >>>>> Inventra DMA, OMAP sDMA and ux500 DMA engines supported by the driver. >>>>> Granted, CPPI 4.1 makes some assumptions about the fact that it's >>>>> handling USB tranfers, >>>> What CPPI 4.1 code makes this assumptions? MUSB DMA driver? Then it's just >>> HW makes the asumptions >> Not true at all. There is a separate set of registers (at offset 0) which >> copes with USB specifics, but CPPI 4.1 itself doesn't know about USB anything. > CPPI 4.1 was made for USB transfers. Utter nonsense, CPPI 4.1 is hardware abstract DMA engine. It's used for Ethernet transfers on out-of-tree platforms like mach-avalanche/. >> It's just the way the driver was written that it used both sets of registers but >> this needs to be changed into more abstacted accesses to the USB-specific part, >> to cope with it being different on different platfroms, like AM35x. The driver >> as it was last posted, just needs rework now. > are you saying you will do the work ? My efforts stopped to be funded by MV back in 2010. Hell, I'm not even working in MV as I used to, hanging on the verge of my current contract being terminated. >>>> Don't know, I was quite content with the abstraction when writing CPPI 4.1 >>>> driver for MUSB... >>> look closer. The whole: >>> if (is_cppi()) >>> foo(); >>> else if (is_inventra()) >>> bar(); >>> else if (is_omap_sdma()) >>> baz(); >>> is bogus. >> That part -- yes. There were attempt to get rid of this, but without changing >> the DMA API. It was left halfway done after my only critical comment, IIRC. Will >> we ever see the continuation of this effort? > patches are welcome There was a patch, it only needed comments addressed. I think the author was Heikki Krogerus. As for me, my time is very limited, so be thankful even for those scarce patches I'm sending out now -- I'm doing them in my copious free time. WBR, Sergei