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From: Marek Vasut <marex@denx.de>
To: Yao Yuan <yao.yuan@freescale.com>
Cc: "wsa@the-dreams.de" <wsa@the-dreams.de>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"shawn.guo@linaro.org" <shawn.guo@linaro.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>
Subject: Re: [PATCH v5 0/2] i2c: add DMA support for freescale i2c driver
Date: Thu, 24 Jul 2014 06:16:40 +0200	[thread overview]
Message-ID: <201407240616.40858.marex@denx.de> (raw)
In-Reply-To: <e5547e015bf6447e9b4fc18e82ddce74@BL2PR03MB338.namprd03.prod.outlook.com>

On Thursday, July 24, 2014 at 05:36:34 AM, Yao Yuan wrote:
> Hi,
> 
> Marek Vasut wrote:
> > On Wednesday, July 23, 2014 at 10:24:41 AM, Yuan Yao wrote:
> > > Changed in v5:
> > > - add "*chan_dev = dma->chan_using->device->dev" for reduce the call
> > > time.
> > 
> > Did you check if the compiler generates different code ?
> 
> Sorry, I didn't compare the assembly code. It's a subtle change.
> As you mentioned the "noodle" before.
> 
> Old:
> dma_map_single(dma->chan_using->device->dev, ...);
> dma_mapping_error(dma->chan_using->device->dev, ...);
> dma_unmap_single(dma->chan_using->device->dev, ...);
> 
> New:
> struct device *chan_dev = dma->chan_using->device->dev;
> dma_map_single(chan_dev, ...);
> dma_mapping_error(chan_dev, ...);
> dma_unmap_single(chan_dev, ...);

You should not use optimization and code cleanup interchangably. Thanks for 
clarifying what this is.

Best regards,
Marek Vasut

      reply	other threads:[~2014-07-24  4:16 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-23  8:24 [PATCH v5 0/2] i2c: add DMA support for freescale i2c driver Yuan Yao
2014-07-23  8:24 ` [PATCH v5 1/2] " Yuan Yao
2014-07-23  9:48   ` Lothar Waßmann
2014-07-23 11:11     ` Yao Yuan
2014-07-23 11:14       ` Varka Bhadram
2014-07-23 12:15         ` Lothar Waßmann
2014-07-23 16:52           ` Marek Vasut
2014-07-31  6:16             ` Yao Yuan
2014-07-23 12:11       ` Lothar Waßmann
2014-07-23  8:24 ` [PATCH v5 2/2] Documentation:add " Yuan Yao
2014-07-23 12:28 ` [PATCH v5 0/2] i2c: add " Marek Vasut
2014-07-24  3:36   ` Yao Yuan
2014-07-24  4:16     ` Marek Vasut [this message]

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