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| author | Brian Norris <computersforpeace@gmail.com> | 2012-10-10 08:26:06 +0200 |
|---|---|---|
| committer | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-11-15 14:37:16 +0100 |
| commit | af451af4e0a3a4cd7536843f585c96a9b095a4e8 (patch) | |
| tree | 10d132c5575d02a3d8647855c14d526733fe5633 | |
| parent | jffs2: Fix lock acquisition order bug in jffs2_write_begin (diff) | |
| download | linux-af451af4e0a3a4cd7536843f585c96a9b095a4e8.tar.xz linux-af451af4e0a3a4cd7536843f585c96a9b095a4e8.zip | |
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>
| -rw-r--r-- | drivers/mtd/nand/nand_base.c | 9 |
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; |