From: Brian Norris Date: Wed, 10 Oct 2012 06:26:06 +0000 (-0700) Subject: mtd: nand: fix Samsung SLC NAND identification regression X-Git-Tag: v3.7-rc7~5^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc86cf7af2ebda88056538e8edff852ee627f76a;p=pandora-kernel.git 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 Tested-by: Brian Norris Reported-by: Marek Vasut Tested-by: Marek Vasut Signed-off-by: David Woodhouse --- Reading git-diff-tree failed