On Fri, 23 Nov 2018 11:17:29 +0100 Boris Brezillon <boris.brezil...@bootlin.com> wrote:
> On Fri, 23 Nov 2018 09:42:55 +0000 > "Sverdlin, Alexander (Nokia - DE/Ulm)" <alexander.sverd...@nokia.com> > wrote: > > > Hello Tudor, > > > > On 22/11/2018 13:36, tudor.amba...@microchip.com wrote: > > > From: Tudor Ambarus <tudor.amba...@microchip.com> > > > > > > Bug reported for the out-of-tree S25FS128S flash memory. > > > > > > BFPT table advertises all the erase types supported by all the > > > possible map configurations. Update the erase_type array to indicate > > > which erase types are applicable to the current map configuration. > > > > > > Backward compatibility test done on sst26vf064b. > > > > > > Fixes: b038e8e3be72 ("mtd: spi-nor: parse SFDP Sector Map Parameter > > > Table") > > > Reported-by: Alexander Sverdlin <alexander.sverd...@nokia.com> > > > Signed-off-by: Tudor Ambarus <tudor.amba...@microchip.com> > > > > I've tested this patch and it fixes the erasesize for S25FS128S and > > our 128k partitions are writeable again with this patch. > > > > Nevertheless, I think this is coincidence. I don't think that it > > makes sense to OR all the erase types from all regions in one > > bitmask and derive any uniform erasesize out of it. > > This makes little sense for me in case of non-uniform maps. > > > > I believe, the culprit here is one level higher, in the MTD partitioning > > code (mtdpart.c) which has to be taught about non-uniform maps > > but there is no infrastructure for this currently. > > Keep in mind that mtdpart is only one part of the issue. As I said > previously, some MTD users (UBI) expect a single eraseblock size, so > it's not only mtdpart that you'd need to fix, but basically all MTD > users that don't check ->eraseregions. Just checked, and it seems mtdpart already supports eraseregions [1]. It picks the biggest erasesize of the regions covered by the partition, which is exactly what we want. So all we'd have to do is make spi-nor.c define those regions. [1]https://elixir.bootlin.com/linux/v4.20-rc3/source/drivers/mtd/mtdpart.c#L482