On Mon, Sep 03, 2012 at 12:55:34PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > On 12:32 Mon 03 Sep , Juergen Beisert wrote: > > Hi all, > > > > currently I'm working on the difficult process to make an i.MX35 SoC boot from > > an externally connected NAND device. > > > > Nothing special with it, only the NAND flash controller in the i.MX35 (also in > > i.MX25, i.MX27 and i.MX31) is braindamaged broken. This controller loses the > > factory bad block markers when used without a workaround and losing these > > markers is a _really_ bad idea. > > > > But to use the workaround on these SoCs it needs a complicated preparation of > > the NAND. Doing it manually is very error prone. And this kind of preparation > > has to be kept when the system should be updated and so on. Not easy to > > explain and so much more chances for the user to brick the system while the > > update process. > > > > This makes me think about a dedicated command which is responsible to make the > > target bootable and does all the (more or less complicated) steps to ensure > > the next time it gets powered it's able to boot again. > > > > There are more architectures which needs a complicated setup to be able to > > boot it from some kind of externally connected devices like NAND or eMMCs for > > example. Some needs special NAND checksums only for the bootloader, others > > needs to keep the partition table even if the bootloader gets updated and so > > on. > > > > Would it be possible to share one command (or one group of commands) by all > > architectures? And each architecture adds its special code to the command? > > > > What kind of setup procedures we must cover with such a command? > > > > My examples: > > > > - for the Freescale i.MX SoCs with the broken NFC we must write the bootloader > > in a different way than all the remaining data into the NAND device > > - for the Samsung S36410 we must save the factory bad block markers first to > > support booting from NAND as its internal ROM expects the checksums at a > > strange offset in the OOB area > On some ST SoC it's the same I think we do not need any command we just need > to specify it as mtd level for a specific mtd part A command has the advantage that for example we could also check for valid images before flashing them (does it have a correct barebox header?). This could be checked before actually erasing a sector. Also, flashing boot images is not limited to mtd devices, it could also be mmc, or for OMAP, not a device at all but a file inside a FAT on SD card. 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
