On Mon, Jul 04, 2016 at 12:32:04PM +0000, Martin Hollingsworth wrote: > Hello folks, > I'm a little lost when trying to overwrite an ext partition on an eMMC > memory inside of barebox. Your help finding the mistake is > appreciated. > > My Setup: > - Custom board with iMX6, 4GB eMMC and SD card reader (similar to Freescale SabreSD board) > - Using PTXdist to build barebox 2016.05.0 and linux > - The eMMC chip offers wear levelling, so I write a filesystem directly to it (using ptxdist created hd.img file flashed directly) > - The eMMC is partitioned as follows: > 0x0, Size 1k --> partition table > 0x400, Size 8M --> barebox and barebox_env (offset 0x400 forced by iMX6) > 0x800400, Size 1G --> ext filesystem with rootfs and kernel > > With this layout so far everything works fine. Now I would like to > implement an update mechanism, where barebox erases the complete ext > partition and replaces it. Under linux I would use something like dd > and let it start at 0x800400. On barebox I have to use memcpy (thanks > to Sascha for the hint > http://lists.infradead.org/pipermail/barebox/2011-April/003308.html ) > and this is where I get stuck. > > So I first add partitions so that the memory area is listed under /dev: > devfs_add_partition("mmc3", 0x0, SZ_1K, DEVFS_PARTITION_FIXED, "mmc3.partable"); > devfs_add_partition("mmc3", SZ_1K, SZ_8M, DEVFS_PARTITION_FIXED, "mmc3.barebox"); > devfs_add_partition("mmc3", ( SZ_1K + SZ_8M ), SZ_1G, DEVFS_PARTITION_FIXED, "mmc3.rootfs"); Why don't you use the partitions from the partition table on the device? I would assume you use /dev/mmc3.2 for the rootfs. > > This works for clearing the partitions data using memset: > memset -d /dev/mmc3.rootfs 0x0 0x0 1073741824 > > However when I try to copy the root.ext2 filesystem onto this memory area, I can't mount the partition afterwards: > memcpy -s /mnt/sd/root.ext2 -d /dev/mmc3.rootfs 0 536870912 memcpy needs <src> <dest> <count> positional arguments. With the above 536870912 is the offset in the destination file and not the size to copy. What you want is: memcpy -s /mnt/sd/root.ext2 -d /dev/mmc3.rootfs 0 0 536870912 Anyway, you don't need memset/memcpy at all to accomplish your task, the following should do it: cp /dev/zero /dev/mmc3.rootfs cp /mnt/sd/root.ext2 /dev/mmc3.rootfs Also I have never seen that it's necessary to erase the remaining parts of a partition when the new image is smaller than the partition. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
