On Mon, Mar 07, 2016 at 10:46:50AM +0100, Boris Brezillon wrote:

Hello,

This patchset aims at getting rid of the nand_ecclayout limitations.
struct nand_ecclayout is defining fixed eccpos and oobfree arrays which
can only be increased by modifying the MTD_MAX_ECCPOS_ENTRIES_LARGE and
MTD_MAX_OOBFREE_ENTRIES_LARGE macros.
This approach forces us to modify the macro values each time we add a
new NAND chip with a bigger OOB area, and increasing these arrays also
penalize all platforms, even those who only support small NAND devices
(with small OOB area).

The idea to overcome this limitation, is to define the ECC/OOB layout
by the mean of two functions: ->ecc() and ->free(), which will
basically return the same information has those stored in the
nand_ecclayout struct.

Another advantage of this solution is that ECC layouts are usually
following a repetitive pattern (i.e. leave X bytes free and put Y bytes
of ECC per ECC chunk), which allows one to implement the ->ecc()
and ->free() functions with a simple logic that can be applied
to any size of OOB.

Patches 1 to 4 are just cleanups or trivial fixes that can be taken
independently.

Also note that the last two commits are removing the nand_ecclayout
definition, thus preventing any new driver to use this structure.
Of course, this step can be delayed if some of the previous patches
are not accepted.

All those changes are available here [1].

Best Regards,

Boris

[1]https://github.com/bbrezillon/linux-0day/tree/nand/ecclayout

FYI, I've pushed patches 1-4 to l2-mtd.git. I'll take another look at
them this week I hope (or your new fellow, Richard, can!), then you can
queue them up for the next cycle.

Brian