changing mtd partitioning
sean at mcneil.com
Fri Apr 11 19:28:59 CEST 2008
Werner Almesberger wrote:
> Sean McNeil wrote:
>> What does dynpart refer to then when it says is reads from BBT.
> Hmm, when does it say something like this ?
> It does read the BBT, that's true. It does so to find out how much space
> it has to leave for bad blocks. (By the way, all this is mainly about
> blocks marked as "bad" at the factory.)
I messed up serial console to uboot, but I'm pretty sure it said it in the
>> And why doesn't dynpart obey what is written in the env?
> Dynpart creates the mtdparts information. Its own input, i.e., partition
> names and sizes, is hard-coded in u-boot, in dynpart_size and
> dynpart_names in board/neo1973/gta02/gta02.c
Ah, ok. Is there some sort of max number of partitions that the kernel
recognizes? I didn't get to trace down why I didn't see the new layout
when I booted.
> As Andy has already pointed out, we don't quite like this approach
> anymore. But it's a legacy that has survived until GTA02.
> It's interesting to note that, had we sized partitions statically such
> that there some "slack" blocks in each to accommodate bad blocks, it seems
> that we would have had to spend 1% of the NAND size for slack blocks if
> we'd wanted to aim for a <10^-6 per-partition risk of not having enough
> slask, or 1.5% of the NAND for a <10^-9 risk. Assuming that bad blocks are
> evenly distributed and that my calculations are correct:
> - Werner
More information about the openmoko-kernel