From mboxrd@z Thu Jan 1 00:00:00 1970 From: svenkatr@ti.com (Venkatraman S) Date: Thu, 11 Mar 2010 16:22:19 +0530 Subject: [PATCH 03/03] omap hsmmc: adaptation of sdma descriptor autoloading feature In-Reply-To: <011301cac0b6$542b1190$544ff780@am.dhcp.ti.com> References: <618f0c911003010327s290fcce1ud665b5a16392aea1@mail.gmail.com> <011301cac0b6$542b1190$544ff780@am.dhcp.ti.com> Message-ID: <618f0c911003110252i36d6fc31wbaef4ad7a17565b1@mail.gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Madhusudhan wrote: >> -----Original Message----- >> From: linux-mmc-owner at vger.kernel.org [mailto:linux-mmc- >> owner at vger.kernel.org] On Behalf Of Venkatraman S >> Sent: Monday, March 01, 2010 5:27 AM >> To: linux-mmc at vger.kernel.org; linux-arm-kernel at lists.infradead.org; >> linux-omap at vger.kernel.org >> Subject: [PATCH 03/03] omap hsmmc: adaptation of sdma descriptor >> autoloading feature >> >> Start to use the sDMA descriptor autoloading feature. >> For large datablocks, the MMC driver has to repeatedly setup, program >> and teardown the >> dma channel for each element of the sglist received in omap_hsmmc_request. >> >> By using descriptor autoloading, transfers from / to each element of >> the sglist is pre programmed >> into a linked list. The sDMA driver completes the entire transaction >> and provides a single interrupt. >> >> Due to this, number of dma interrupts for a typical 100MB transfer on the >> MMC is >> reduced from 25000 to about 400 (approximate). Transfer speeds are >> improved by ~5% >> (Though it varies on the size of read / write & improves on huge >> transfers) >> >> Descriptor autoloading is available only in 3630 and 4430 (as of now). >> Hence normal DMA >> mode is also retained. >> >> Tested on omap4430 sdp. >> >> Signed-off-by: Venkatraman S > > I don't see any issues with this patch except the concern I had on the first > patch in the series. Why is that change linked to this series? > Thanks. The problem was seen only in the context of using descriptor load. Would you prefer that I post it as a separate patch ? Regards, Venkat.