mtd: nand: fix Samsung SLC NAND identification regression
A combination of the following two commits caused a regression in 3.7-rc1
when identifying some Samsung NAND, so that some previously working NAND
were no longer detected properly:
commit e3b88bd604283ef83ae6e8f53622d5b1ffe9d43a
mtd: nand: add generic READ ID length calculation functions
commit e2d3a35ee427aaba99b6c68a56609ce276c51270
mtd: nand: detect Samsung K9GBG08U0A, K9GAG08U0F ID
Particularly, a regression was seen on Samsung K9F2G08U0B, with the
following full 8-byte READ ID string:
ec da 10 95 44 00 ec da
The basic problem is that Samsung manufactures both SLC and MLC NAND
that use a non-standard decoding table for deriving information from
their IDs. I have heuristically determined that all the chips that use
the new table have ID strings which wrap around after the 6th byte.
Unfortunately, I overlooked the fact that some older Samsung SLC (which
use a different decoding table) have "5 byte ID strings" which also wrap
around after the 6th byte.
This patch re-introduces a distinction between these old and new Samsung
NAND by checking that the 6th byte is non-zero, allowing both old and
new Samsung NAND to be detected properly.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Tested-by: Brian Norris <computersforpeace@gmail.com>
Reported-by: Marek Vasut <marex@denx.de>
Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
1 file changed