From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peng Fan Date: Sun, 24 Jan 2016 21:04:25 +0800 Subject: [U-Boot] [PATCH] imx: mx6sxsabresd: support emmc In-Reply-To: <56A4B062.9020803@denx.de> References: <1450775035-2339-1-git-send-email-van.freenix@gmail.com> <20151223031052.GC24788@linux-7smt.suse> <56A4B062.9020803@denx.de> Message-ID: <20160124130423.GA21705@linux-7smt.suse> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Stefano, On Sun, Jan 24, 2016 at 12:07:14PM +0100, Stefano Babic wrote: >Hi Peng, > >On 23/12/2015 04:10, Peng Fan wrote: >> Hi Otavio, >> On Tue, Dec 22, 2015 at 09:51:37AM -0200, Otavio Salvador wrote: >>> On Tue, Dec 22, 2015 at 7:03 AM, Peng Fan wrote: >>>> From: Peng Fan >>>> >>>> For i.MX6SX SABRESD, USDHC4 can be used for SD and EMMC, default >>>> it is used for SD. >>>> >>>> This patch introduces EMMC pinmux settings and a new macro >>>> CONFIG_MX6SXSABRESD_EMMC_REWORK. If the board has been reworked >>>> to support emmc, need to enable this macro. >>>> >>>> Signed-off-by: Peng Fan >>>> Cc: Stefano Babic >>> >>> Is it worth supporting this 'reworked' board? if someone reworks a >>> board it is expected to have to rework the BSP of it, as well. >> >> usdhc4 can be used for SD and emmc. This is the feature of the board, >> so I think we need to support it. But there is no way to dynamically check >> whether using sd or emmc now, adding the macro for using emmc. > >I agree with Otavio that this is a very nasty hack, and the hardware >developer should provide a way getting the board revision. Anyway, I >would not certainly block it, as it concerns just this board, but I ask >if it is not better to let decide to an environment variable if eMMC >must be activated. Advantage is to have a single U-Boot binary for both >boards, disadvantage is that it coul be set for the wrong board >revision, too. But if USDHC4 was not used anymore, this drives just to a >not found eMMC. Both ways are hacks, I fully agree, but >CONFIG_MX6SXSABRESD_EMMC_REWORK remains undocumented at all, too. > >What do you think ? There is no fuse bit or else to let uboot do runtime checking. I also disklike this, but I do not have a better idea. Without runtime checking, it's hard to use one image support SD/EMMC both. I would like to add doc for the macro CONFIG_MX6SXSABRESD_EMMC_REWORK in the next version, do you agree with this? Thanks, Peng. > >Best regards, >Stefano Babic > >-- >===================================================================== >DENX Software Engineering GmbH, Managing Director: Wolfgang Denk >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 >=====================================================================