From mboxrd@z Thu Jan 1 00:00:00 1970 From: eric.nelson@boundarydevices.com (Eric Nelson) Date: Wed, 10 Jun 2015 07:36:00 -0700 Subject: [PATCH 4/6] mmc: sdhci-esdhc-imx: config watermater levles and burst lengths In-Reply-To: <1433926244-29244-5-git-send-email-haibo.chen@freescale.com> References: <1433926244-29244-1-git-send-email-haibo.chen@freescale.com> <1433926244-29244-5-git-send-email-haibo.chen@freescale.com> Message-ID: <55784B50.6030101@boundarydevices.com> To: linux-arm-kernel@lists.infradead.org List-Id: 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