From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Date: Sat, 11 Aug 2012 19:25:26 +0200 Subject: [U-Boot] [PATCH] fsl_esdhc: Add no-snoop config for default init In-Reply-To: <192671166.2300459.1344695995863.JavaMail.root@advansee.com> References: <192671166.2300459.1344695995863.JavaMail.root@advansee.com> Message-ID: <50269586.1060802@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 11/08/2012 16:39, Beno?t Th?baudeau wrote: > Hi Stefano, > Hi, > fsl_esdhc_mmc_init() exists, so it should give access to all features. This was left for compatibility with PowerPC SOCs. > Moreover, > it's shorter to #define a config option than to create custom fsl_esdhc_mmc init > functions when only a single eSDHC instance is needed. However, the number of CONFIG_ continues to increase, often not well documented. > > Besides that, the cache snooping feature is not available on i.MX, which means > that without CONFIG_SYS_FSL_ESDHC_NO_SNOOP or an equivalent, boards using > fsl_esdhc_mmc_init() will make esdhc_init() access a reserved bit of a reserved > register, which is not really recommended. It should be masked by the i.MX code. You add CONFIG_SYS_FSL_ESDHC_NO_SNOOP and this is set inside the board configuration file. But this is not a board configuration option, rather a SOC option. Then it should the initialization code of i.MX that should hide this bit to the board itself. Instead of this, I think it is better to change cpu_mmc_init() in arch/arm/cpu/armv7/imx-common/cpu.c, setting the structure and fixing the soop bit to 1, because i.MX has not this feature. Then all i.MX boards using ESDHC have the no_snoop bit set. > On i.MX, the patch could also be improved by not making this option available, > but behaving as if it were set. Right. It should not be configurable. We know that the i.MXs have no snoop cabability. Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de =====================================================================