On Mon, 2024-09-30 at 15:18 +0100, Peter Maydell wrote: > On Fri, 6 Sept 2024 at 17:51, Jan Luebbe <j...@pengutronix.de> wrote: > > > > The enable bits in the EXT_CSD_PART_CONFIG ext_csd register do *not* > > specify whether the boot partitions exist, but whether they are enabled > > for booting. Existence of the boot partitions is specified by a > > EXT_CSD_BOOT_MULT != 0. > > > > Currently, in the case of boot-partition-size=1M and boot-config=0, > > Linux detects boot partitions of 1M. But as sd_bootpart_offset always > > returns 0, all reads/writes are mapped to the same offset in the backing > > file. > > > > Fix this bug by calculating the offset independent of which partition is > > enabled for booting. > > Looking at the spec this change seems correct to me. > > Can you elaborate on when users might run into this bug? > As far as I can see only aspeed.c sets boot-partition-size, > and when it does so it also sets boot-config to 8. Or are > we fixing this for the benefit of future board types?
I stumbled across this when trying to use the eMMC emulation for the RAUC test suite (with some unrelated local hacks, which I still need to clean up for submission) [1]. Future boards would be affected as well. One other possible issue would be disabling the boot partition by using 'mmc bootpart enable 0 0 /dev/mmcblk0' (or similar) from Linux. The layout of the backing file shouldn't change in that case. Regards, Jan [1] https://github.com/rauc/rauc/tree/master/test -- 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 |
