On Tue, Jun 15, 2021 at 7:35 AM Sascha Hauer <sha@xxxxxxxxxxxxxx> wrote: > > > > I do not see any imx nand xloader users at all in mainlinux Barebox > > codebase. Which is annoying, since I'm trying to boot barebox from > > NAND on iMX6ULL and there are no boards in barebox that do this. So I > > have to do it from scratch, even though I know such boards exist and > > in fact you are using one. > > > > Do I do not know of any specific imx6 boards that do this. As there > > are apparently no imx boards booting barebox from nand.... > > There are several i.MX6 boards mainline that support booting from NAND, > one of them being the phyFLEX-i.MX6 board which I am using all day. It > doesn't use any xload mechanism, theres's only one stage in NAND. We > also have imx6_nand_start_image() which can be used when a xload > mechanism is desired for cases when the SDRAM shall be initialized in > code rather than using DCD data. This part indeed has no users in tree, > but there shouldn't be much to implement to get this working. That's the issue, this patch is to the code for xload, which has no in tree users. The patch either doesn't matter, fixes, or breaks a board, depending on what it did with NAND. A normal NAND layout doesn't matter, but there are "wrong", or at least non-standard, layouts that it will either fix or break. Andrej has one real example where it fixes. There are no known specific examples where it would break, but absence of evidence is not evidence of absence! If there was an in-tree board using xload gpmi, then one could also look for a BSP software update system or published software update instructions for that board, and see what they do. For example, Variscite's DART-6UL instructions for u-boot update from Linux in §5.4 of https://variwiki.com/index.php?title=Yocto_NAND_Flash_Burning&release=RELEASE_ZEUS_V1.2_DART-6UL These have both SPL + 2nd stage replacement in one block, which is good and this patch will not break a board flashed this way. Of course, SPL flash uses kobs-ng, which needs the debugfs bch hack that's not in the mainline kernel, so maybe someone skips that step and doesn't update SPL? > > But consider that even if barebox spl can support two different BCH > > configs on same nand device for booting, neither Barebox nor Linux > > support this concept at all. > > At least the OMAP NAND driver in barebox supports different ECC configs > that are switchable during runtime. The ECC scheme once switched is used > for the whole device though, what's missing is indeed to attach an ECC > scheme to a partition rather than to the whole device. I have that dream > each time when hacking OMAP NAND... Even if Barebox could do it, it won't work in Linux, which would be a huge drawback. AFAIK, even the new dts based ECC properties are still attached to a device and not a partition. When hardware ECC first appeared, it seemed obvious to me that an mtd ioctl to get/set ecc values was needed. kobs-ng needs this. The thing I can't remember for the MXS boot system needed it. One could have different ECC for different partitions. One could switch the ECC used when reflashing a partition. But no, we have stuff like the debugfs bch file that is still not mainlined after a decade. _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
