From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joel Fernandes Subject: Re: [PATCH 1/3] dmaengine: add dma_get_slave_sg_limits() Date: Mon, 22 Jul 2013 16:45:51 -0500 Message-ID: <51EDA80F.7060606@ti.com> References: <1374166001-31340-1-git-send-email-joelf@ti.com> <1374166001-31340-2-git-send-email-joelf@ti.com> <20130718161658.GW16653@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130718161658.GW16653-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: Errors-To: davinci-linux-open-source-bounces-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org To: Vinod Koul Cc: Mark Brown , Tony Lindgren , Grant Likely , Russell King , Linux Documentation List , Chris Ball , Arnd Bergmann , Devicetree Discuss , Rob Herring , Jason Kridner , Benoit Cousson , Linux OMAP List , Linux ARM Kernel List , Linux DaVinci Kernel List , Balaji TK , Mark Jackson , Linux MMC List , Linux Kernel Mailing List List-Id: devicetree@vger.kernel.org On 07/18/2013 11:16 AM, Vinod Koul wrote:> On Thu, Jul 18, 2013 at 11:46:39AM -0500, Joel Fernandes wrote: >> From: Matt Porter >> >> Add a dmaengine API to retrieve slave SG transfer limits. >> >> The API is optionally implemented by dmaengine drivers and when >> unimplemented will return a NULL pointer. A client driver using >> this API provides the required dma channel, address width, and >> burst size of the transfer. dma_get_slave_sg_limits() returns an >> SG limits structure with the maximum number and size of SG segments >> that the given channel can handle. > Hi Joel, > > I have already resurrected this and generalized the API to get the slave > capablities. > https://lkml.org/lkml/2013/7/15/147 Hi Vinod, get_caps and get_sg_limits are 2 different things, looks like this was already discussed earlier, and this patch series is a separate API that adds support for SG limits. Infact, you can already see here that he changed the name of the function from caps to dma_get_slave_sg_limits: http://linux.davincidsp.com/pipermail/davinci-linux-open-source/2013-March/026601.html Considering this, what is the way forward? Can this patch series be merged as it is a different API as discussed above? Summarizing: * get_caps API cannot be used for this same purpose, as get_caps is done _before_ the DMA channel can be configured from what it looks like: * get_sg_limits, on the other hand is supposed to already have the parameters required for configuring the DMA channel before hand. Are there any other changes to the get_sg_limits series you would like before it can be applied? Any other suggestions? Thanks, -Joel