From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Date: Thu, 09 Jan 2014 17:45:55 +0900 Subject: [U-Boot] Are mmc open/close subcommands needed? In-Reply-To: <52CBB107.9050607@digi.com> References: <52C5996C.4020803@digi.com> <201401030036.41329.marex@denx.de> <52CBB107.9050607@digi.com> Message-ID: <52CE61C3.3090204@samsung.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 01/07/2014 04:47 PM, Hector Palacios wrote: > Dear Otavio, > > On 01/03/2014 06:35 PM, Otavio Salvador wrote: >> On Thu, Jan 2, 2014 at 9:36 PM, Marek Vasut wrote: >>> On Thursday, January 02, 2014 at 05:53:00 PM, Hector Palacios wrote: >>>> Hi, >>>> >>>> I saw commit 2a91c9134675140853577b565210458b5774e6cf that introduces mmc >>>> subcommands 'open' and 'close' to access eMMC boot partitions and was >>>> wondering if they are really needed. Can't the same be achieved with >>>> already existing 'mmc dev [dev] [part]' command? >>>> >>>> mmc open >>>> is the same as >>>> mmc dev >>>> where is the boot partition >>>> >>>> mmc close >>>> is the same as >>>> mmc dev 0 >>>> as a 0 will switch to partition 0 (user data). >>>> >>>> Best regards, >>>> -- >>>> Hector Palacios >>> >>> +CC Panto >> >> No; this is for different use. >> >> The open and close are to open the Boot partitions part of eMMC 4; by >> default those eMMC will be using the user partitions, not the boot >> area. >> >> The nice, and confusing thing, is that those boot partitions also >> start in address 0 as a 'virtual disk'. > > I don't think they are different commands that do the same by coincidence. The 'mmc dev' command, when passed a fourth argument for the partition is calling the function 'mmc_switch_part()'. > This function executes the CMD6 command to write the Extended CSD register PARTITION_CONFIG field that gives you access to any MMC partition (user data area, boot partitions 1 and 2, RPMB, General Purpose 1-4 partitions). > > It doesn't look like specific eMMC commands are needed to access the boot partitions, but maybe I'm misinterpreting the code. Well, I think also your opinion. This code is the same behavior. I didn't find any difference... Best Regard, Jaehoon Chung > > Best regards, > -- > Hector Palacios > _______________________________________________ > U-Boot mailing list > U-Boot at lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot >