From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bryan Wu Subject: Re: [PATCH 01/16] Blackfin SPI Driver: ensure cache coherency before doing DMA Date: Thu, 5 Feb 2009 17:30:06 +0800 Message-ID: <386072610902050130k27c6d7far752ac49183bf36ae@mail.gmail.com> References: <1226994760-4301-1-git-send-email-cooloney@kernel.org> <200811201347.46355.david-b@pacbell.net> <8bd0f97a0811201357g1ffeb7d3pfad6e178fb20050e@mail.gmail.com> <200811201405.06811.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Vitja Makarov , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mike Frysinger To: David Brownell , Andrew Morton Return-path: In-Reply-To: <200811201405.06811.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org On Fri, Nov 21, 2008 at 6:05 AM, David Brownell wrote: > On Thursday 20 November 2008, Mike Frysinger wrote: >> On Thu, Nov 20, 2008 at 16:47, David Brownell wrote: > >> > Basically, dma_map_single(), dma_unmap_single() ... and >> > remember that the caller may have done the mappings for >> > you already. >> >> these arent required to provide coherent memory right ? if that's the >> case, i can take a look at getting things updated. > > Right. If caller provides dma-coherent memory to you, they > must also have provided the DMA addresses the controller > driver should be using ... so you won't need dma mapping > calls on those paths. > > >> > It'd be nice if one of patches snuck in a comment on that >> > point: "Full duplex only works for non-DMA transfers." >> > Same rationale: you may know this hardware inside out, >> > but the next person won't. >> >> well, hopefully if they dont know they wont be touching the driver ;). >> i'll add a comment in this code chunk. thanks for the feedback. > > The way it usually works is someone observes a problem and > then starts experimenting on relevant code. So they learn > a bit while debugging ... and code authors/maintainers need > to keep that learning curve from being too steep. ;) > > - Dave > > Hi Dave, As you acked this patchset, is that possible to merge it? Or need Andrew to keep them in -mm for a while. Thanks -Bryan ------------------------------------------------------------------------------ Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com