[PATCH] mtd: Introduce CONFIG_MTD_RESERVE_END
Brian Norris
computersforpeace at gmail.com
Wed May 6 20:27:12 PDT 2015
On Fri, May 01, 2015 at 01:57:13PM +0200, Jonas Gorski wrote:
> On Thu, Apr 30, 2015 at 7:36 PM, Ben Shelton <ben.shelton at ni.com> wrote:
> > The reason for doing this as a Kconfig option rather than with an additional
> > partition is that we use the same .itb boot image (and kernel arguments) for
> > a series of embedded controllers that have different NAND flash sizes, and we
> > use the '-' command line parameter to give the root partition all the available
> > space after the other partitions.
>
> Wouldn't it make more sense to make cmdlineparts to recognize if it is
> run on a nand flash that has on-flash BBT enabled, and then reduce the
> SIZE_REMAINING partition's size by the amount of nand_bbt_descr's
> maxblocks * erase block size?
That's a possibility, but that seems like a bit too much hidden policy
to add on top of the cmdlineparts format, which is pretty precise.
A better improvement, if you're dead set on using cmdlineparts rather
than some other better parser, might be to support something like:
mtdparts=name:-(main),bbt(1M)
So the "remaining space" partition will allow for following partitions.
IOW, you would need to handle this case, which is currently an error:
/* test if more partitions are following */
if (*s == ',') {
if (size == SIZE_REMAINING) {
printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
return ERR_PTR(-EINVAL);
}
...
}
> Currently your proposed solution would break if boards have differing
> erase block sizes, or if some have NOR flash, which makes it an option
> for a rather narrow use case IMHO.
Yeah, consider this a NAK for the current patch.
Brian
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