From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Date: Thu, 09 Sep 2010 15:35:08 +0200 Subject: [U-Boot] status of patch to store environment to mmc/sd In-Reply-To: <4C88DF18.7090909@emk-elektronik.de> References: <4C88DB3E.70703@denx.de> <4C88DF18.7090909@emk-elektronik.de> Message-ID: <4C88E28C.7080508@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 Reinhard Meyer wrote: > Dear Stefano Babic, Hi Reinhard, > Just looking at the patch I see that it writes the env to fixed blocks > on the SD/MMC card. This will work of course. BUT usually (IMHO) such > cards are used with partitions/filesystems. Not always. In the specific case reported by Amit, the mx.51 processor can boot from a SD card, that must not contain partitions at least for the early sectors, where it is supposed there is the u-boot's code. Usage of partitions is not forbidden, however. The partitions must only start after the space required by u-boot and (as supported by the patch in question) by the environment. > How do you make sure the > blocks don't overwrite files or don't get overwritten by files? Writing a correct partition table: the first partition must start after u-boot code and environment, used as raw-blocks. There is then no possibility for files to overwrite the environment or the code. > One can, of course, prepare the card with a small partition spanning > the env blocks. As I said, it is not required to have a partition for the environment, because this is read only as raw-block. It is only required to skip the first blocks (or the block set in the config file). > > Should the env not be saved in a file? Which is probably a bit beyond > possibility to read when not yet relocated... Reading the environment from a file should be in a separate patch and made much more general ;-) It is not related to a specific storage. We could have a filesystem even on other storages (SPI-Flash, NAND, HD...) and "reading from file" should IMHO hide the underlying storage media. Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office at denx.de =====================================================================