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authorBrian Norris <computersforpeace@gmail.com>2012-10-09 23:26:06 -0700
committerArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-11-15 15:37:16 +0200
commitaf451af4e0a3a4cd7536843f585c96a9b095a4e8 (patch)
tree10d132c5575d02a3d8647855c14d526733fe5633 /drivers/mtd
parent5ffd3412ae5536a4c57469cb8ea31887121dcb2e (diff)
downloadlinux-af451af4e0a3a4cd7536843f585c96a9b095a4e8.tar.bz2
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: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Diffstat (limited to 'drivers/mtd')
-rw-r--r--drivers/mtd/nand/nand_base.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ec6841d8e956..d5ece6ea6f98 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2983,13 +2983,14 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
/*
* Field definitions are in the following datasheets:
* Old style (4,5 byte ID): Samsung K9GAG08U0M (p.32)
- * New style (6 byte ID): Samsung K9GAG08U0F (p.44)
+ * New Samsung (6 byte ID): Samsung K9GAG08U0F (p.44)
* Hynix MLC (6 byte ID): Hynix H27UBG8T2B (p.22)
*
- * Check for ID length, cell type, and Hynix/Samsung ID to decide what
- * to do.
+ * Check for ID length, non-zero 6th byte, cell type, and Hynix/Samsung
+ * ID to decide what to do.
*/
- if (id_len == 6 && id_data[0] == NAND_MFR_SAMSUNG) {
+ if (id_len == 6 && id_data[0] == NAND_MFR_SAMSUNG &&
+ id_data[5] != 0x00) {
/* Calc pagesize */
mtd->writesize = 2048 << (extid & 0x03);
extid >>= 2;