From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Nelson Subject: Re: [PATCH 4/6] mmc: sdhci-esdhc-imx: config watermater levles and burst lengths Date: Wed, 10 Jun 2015 07:36:00 -0700 Message-ID: <55784B50.6030101@boundarydevices.com> References: <1433926244-29244-1-git-send-email-haibo.chen@freescale.com> <1433926244-29244-5-git-send-email-haibo.chen@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-pd0-f174.google.com ([209.85.192.174]:33667 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965095AbbFJOgD (ORCPT ); Wed, 10 Jun 2015 10:36:03 -0400 Received: by pdjn11 with SMTP id n11so39251247pdj.0 for ; Wed, 10 Jun 2015 07:36:02 -0700 (PDT) In-Reply-To: <1433926244-29244-5-git-send-email-haibo.chen@freescale.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Haibo Chen , linux-mmc@vger.kernel.org Cc: aisheng.dong@freescale.com, ulf.hansson@linaro.org, chris@printf.net, shawn.guo@linaro.org, linux-arm-kernel@lists.infradead.org Hi Haibo, On 06/10/2015 01:50 AM, Haibo Chen wrote: > i.MX7D support eMMC HS400 mode, this mode can run in 8 bit,200MHZ > DDR mode. So the I/O speed improve a lot compare to SD3.0 > > The default burst length is 8, if we don't change this value, in > HS400 mode, when we do eMMC read operation, we can find that the > clock signal will stop for a period of time. This means the speed > of data moving on AHB bus is slower than I/O speed. So we should > improve the speed of data moving on AHB bus. > > For imx7d usdhc, this patch set the burst length as 16, and set > watermater levle as 64. The test result is the clock signal has > no stop during the eMMC HS400 operation. For other imx usdhc, remain "watermark", not "watermater". > the default value: burst length as 8, watermater level as 16. > Same goes for the subject. Also "levels", not "levles", so: mmc: sdhci-esdhc-imx: config watermark level and burst length