From mboxrd@z Thu Jan 1 00:00:00 1970 From: Huang Shijie Subject: Re: [PATCH] dma: add new DMA control commands Date: Thu, 18 Oct 2012 17:10:46 +0800 Message-ID: <507FC796.7060401@freescale.com> References: <1350538335-29026-1-git-send-email-b32955@freescale.com> <1350541111.5263.3.camel@vkoul-udesk3> <507FA595.4020507@freescale.com> <20121018085208.GR21164@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20121018085208.GR21164-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Russell King - ARM Linux Cc: Vinod Koul , djbw-b10kYP2dOMg@public.gmane.org, khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, cjb-2X9k7bc8m7Mdnm+yROfE0A@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, lrg-l0cyMroinI0@public.gmane.org, broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org, perex-/Fr2/VpizcU@public.gmane.org, tiwai-l3A5Bk7waGM@public.gmane.org, shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, marex-ynQEQJNshbs@public.gmane.org, artem.bityutskiy-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Huang Shijie List-Id: alsa-devel@alsa-project.org =E4=BA=8E 2012=E5=B9=B410=E6=9C=8818=E6=97=A5 16:52, Russell King - ARM= Linux =E5=86=99=E9=81=93: > On Thu, Oct 18, 2012 at 02:45:41PM +0800, Huang Shijie wrote: >> =E4=BA=8E 2012=E5=B9=B410=E6=9C=8818=E6=97=A5 14:18, Vinod Koul =E5=86= =99=E9=81=93: >>> Why cant you do start (prepare clock etc) when you submit the descr= iptor >>> to dmaengine. Can be done in tx_submit callback. >>> Similarly remove the clock when dma transaction gets completed. >> I ever thought this method too. >> >> But it will become low efficient in the following case: >> >> Assuming the gpmi-nand driver has to read out 1024 pages in one >> _SINGLE_ read operation. >> The gpmi-nand will submit the descriptor to dmaengine per page. So w= ith >> your method, >> the system will repeat the enable/disable dma clock 1024 time. At ev= ery >> enable/disable dma clock, >> the system has to enable the clock chain and it's parents ... > And what if you stop using clk_prepare_enable(), and prepare the cloc= k > when the channel is requested and only use clk_enable() in the tx_sub= mit yes. it's a little better. There is nearly no difference between the clk_prepare_enable() and=20 clk_enable() in actually. the clk_gate2_ops does not have any @->prepare. thanks Huang Shijie > method? > From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <507FC796.7060401@freescale.com> Date: Thu, 18 Oct 2012 17:10:46 +0800 From: Huang Shijie MIME-Version: 1.0 To: Russell King - ARM Linux Subject: Re: [PATCH] dma: add new DMA control commands References: <1350538335-29026-1-git-send-email-b32955@freescale.com> <1350541111.5263.3.camel@vkoul-udesk3> <507FA595.4020507@freescale.com> <20121018085208.GR21164@n2100.arm.linux.org.uk> In-Reply-To: <20121018085208.GR21164@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: quoted-printable Cc: marex@denx.de, Huang Shijie , Vinod Koul , shawn.guo@linaro.org, alsa-devel@alsa-project.org, tiwai@suse.de, artem.bityutskiy@linux.intel.com, broonie@opensource.wolfsonmicro.com, linux-mmc@vger.kernel.org, w.sang@pengutronix.de, perex@perex.cz, linux-mtd@lists.infradead.org, linux-i2c@vger.kernel.org, ben-linux@fluff.org, djbw@fb.com, khali@linux-fr.org, cjb@laptop.org, dwmw2@infradead.org, lrg@ti.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , =E4=BA=8E 2012=E5=B9=B410=E6=9C=8818=E6=97=A5 16:52, Russell King - ARM L= inux =E5=86=99=E9=81=93: > On Thu, Oct 18, 2012 at 02:45:41PM +0800, Huang Shijie wrote: >> =E4=BA=8E 2012=E5=B9=B410=E6=9C=8818=E6=97=A5 14:18, Vinod Koul =E5=86= =99=E9=81=93: >>> Why cant you do start (prepare clock etc) when you submit the descrip= tor >>> to dmaengine. Can be done in tx_submit callback. >>> Similarly remove the clock when dma transaction gets completed. >> I ever thought this method too. >> >> But it will become low efficient in the following case: >> >> Assuming the gpmi-nand driver has to read out 1024 pages in one >> _SINGLE_ read operation. >> The gpmi-nand will submit the descriptor to dmaengine per page. So wit= h >> your method, >> the system will repeat the enable/disable dma clock 1024 time. At ever= y >> enable/disable dma clock, >> the system has to enable the clock chain and it's parents ... > And what if you stop using clk_prepare_enable(), and prepare the clock > when the channel is requested and only use clk_enable() in the tx_submi= t yes. it's a little better. There is nearly no difference between the clk_prepare_enable() and=20 clk_enable() in actually. the clk_gate2_ops does not have any @->prepare. thanks Huang Shijie > method? > From mboxrd@z Thu Jan 1 00:00:00 1970 From: b32955@freescale.com (Huang Shijie) Date: Thu, 18 Oct 2012 17:10:46 +0800 Subject: [PATCH] dma: add new DMA control commands In-Reply-To: <20121018085208.GR21164@n2100.arm.linux.org.uk> References: <1350538335-29026-1-git-send-email-b32955@freescale.com> <1350541111.5263.3.camel@vkoul-udesk3> <507FA595.4020507@freescale.com> <20121018085208.GR21164@n2100.arm.linux.org.uk> Message-ID: <507FC796.7060401@freescale.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org ? 2012?10?18? 16:52, Russell King - ARM Linux ??: > On Thu, Oct 18, 2012 at 02:45:41PM +0800, Huang Shijie wrote: >> ? 2012?10?18? 14:18, Vinod Koul ??: >>> Why cant you do start (prepare clock etc) when you submit the descriptor >>> to dmaengine. Can be done in tx_submit callback. >>> Similarly remove the clock when dma transaction gets completed. >> I ever thought this method too. >> >> But it will become low efficient in the following case: >> >> Assuming the gpmi-nand driver has to read out 1024 pages in one >> _SINGLE_ read operation. >> The gpmi-nand will submit the descriptor to dmaengine per page. So with >> your method, >> the system will repeat the enable/disable dma clock 1024 time. At every >> enable/disable dma clock, >> the system has to enable the clock chain and it's parents ... > And what if you stop using clk_prepare_enable(), and prepare the clock > when the channel is requested and only use clk_enable() in the tx_submit yes. it's a little better. There is nearly no difference between the clk_prepare_enable() and clk_enable() in actually. the clk_gate2_ops does not have any @->prepare. thanks Huang Shijie > method? > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754771Ab2JRJHr (ORCPT ); Thu, 18 Oct 2012 05:07:47 -0400 Received: from ch1ehsobe001.messaging.microsoft.com ([216.32.181.181]:42505 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752627Ab2JRJHp convert rfc822-to-8bit (ORCPT ); Thu, 18 Oct 2012 05:07:45 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: 1 X-BigFish: VS1(zz98dIc89bh1432Id799hzz1202h1d1ah1d2ah1082kzzz2dh2a8h668h839h93fhd25he5bhf0ah107ah1288h12a5h12a9h12bdh1354h137ah13b6h1441h1155h) Message-ID: <507FC796.7060401@freescale.com> Date: Thu, 18 Oct 2012 17:10:46 +0800 From: Huang Shijie User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.24) Gecko/20111108 Fedora/3.1.16-1.fc14 Thunderbird/3.1.16 MIME-Version: 1.0 To: Russell King - ARM Linux CC: Vinod Koul , , , , , , , , , , , , , , , , , , , , Huang Shijie Subject: Re: [PATCH] dma: add new DMA control commands References: <1350538335-29026-1-git-send-email-b32955@freescale.com> <1350541111.5263.3.camel@vkoul-udesk3> <507FA595.4020507@freescale.com> <20121018085208.GR21164@n2100.arm.linux.org.uk> In-Reply-To: <20121018085208.GR21164@n2100.arm.linux.org.uk> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8BIT X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 于 2012年10月18日 16:52, Russell King - ARM Linux 写道: > On Thu, Oct 18, 2012 at 02:45:41PM +0800, Huang Shijie wrote: >> 于 2012年10月18日 14:18, Vinod Koul 写道: >>> Why cant you do start (prepare clock etc) when you submit the descriptor >>> to dmaengine. Can be done in tx_submit callback. >>> Similarly remove the clock when dma transaction gets completed. >> I ever thought this method too. >> >> But it will become low efficient in the following case: >> >> Assuming the gpmi-nand driver has to read out 1024 pages in one >> _SINGLE_ read operation. >> The gpmi-nand will submit the descriptor to dmaengine per page. So with >> your method, >> the system will repeat the enable/disable dma clock 1024 time. At every >> enable/disable dma clock, >> the system has to enable the clock chain and it's parents ... > And what if you stop using clk_prepare_enable(), and prepare the clock > when the channel is requested and only use clk_enable() in the tx_submit yes. it's a little better. There is nearly no difference between the clk_prepare_enable() and clk_enable() in actually. the clk_gate2_ops does not have any @->prepare. thanks Huang Shijie > method? >