From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH] i2c: mxs: Add PIO and mixed-DMA support Date: Tue, 8 Jan 2013 19:11:57 +0100 Message-ID: <201301081911.57574.marex@denx.de> References: <1353477088-9660-1-git-send-email-marex@denx.de> <201211220150.37462.marex@denx.de> <20121122115037.GA12080@pengutronix.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121122115037.GA12080-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Fabio Estevam , Shawn Guo List-Id: linux-i2c@vger.kernel.org Hi Wolfram, > On Thu, Nov 22, 2012 at 01:50:37AM +0100, Marek Vasut wrote: > > Dear Marek Vasut, > > > > > Add support for the PIO mode and mixed PIO/DMA mode support. The mixed > > > PIO/DMA is the default mode of operation. This shall leverage overhead > > > that the driver creates due to setting up DMA descriptors even for very > > > short transfers. > > > > > > The current boundary between PIO/DMA 8 bytes, transfers shorter than 8 > > > bytes are transfered by PIO, longer transfers use DMA. The performance > > > of write transfers remains unchanged, while there is a minor > > > improvement of read performance. Reading 16KB EEPROM with DMA-only > > > operations gives a read speed of 39.5KB/s, while with then new > > > mixed-mode the speed is blazing 40.6KB/s. > > > > > > Signed-off-by: Marek Vasut > > > Cc: Fabio Estevam > > > Cc: Shawn Guo > > > Cc: Wolfram Sang > > > > [...] > > > > btw. Wolfram, you might want to drop me some credit into the MX28 i2c > > driver, I suspect most of the code in there is mine now anyway :-D > > It's fine if you do this yourself. I don't see this patch in -next ... or am I looking wrong? Best regards, Marek Vasut