From mboxrd@z Thu Jan 1 00:00:00 1970 From: vinod.koul@intel.com (Vinod Koul) Date: Mon, 29 Jul 2013 12:14:15 +0530 Subject: [PATCH 1/3] dmaengine: add dma_get_slave_sg_limits() In-Reply-To: <51E83A9D.5020008@ti.com> References: <1374166001-31340-1-git-send-email-joelf@ti.com> <1374166001-31340-2-git-send-email-joelf@ti.com> <20130718170825.GZ21614@n2100.arm.linux.org.uk> <51E83A9D.5020008@ti.com> Message-ID: <20130729064415.GF29095@intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jul 18, 2013 at 01:57:33PM -0500, Joel Fernandes wrote: > On 07/18/2013 12:08 PM, Russell King - ARM Linux wrote: > > As for the maximum number of scatterlist entries, really that's a bug in > > the DMA engine implementations if they can't accept arbitary lengths. > > I've created DMA engine drivers for implementations where you have to > > program each segment individually, ones which can have the current and > > next segments, as well as those which can walk a list. Provided you get > > informed of a transfer being completed, there really is no reason for a > > DMA engine driver to limit the number of scatterlist entries that it > > will accept. > > Sure, that makes sense. Can you point to such a typical example > implementation to get some ideas? MXS MMC driver uses this: drivers/mmc/host/mxs-mmc.c And dma engine driver for this is mxs-dma.c ~Vinod --