[PATCH 6.6 348/396] mtd: spinand: Add support for 5-byte IDs

Greg Kroah-Hartman
2024-04-01T16:53:41Z

From: Ezra Buehler <ezra.buehler@husqvarnagroup.com>

commit 34a956739d295de6010cdaafeed698ccbba87ea4 upstream.

E.g. ESMT chips will return an identification code with a length of 5
bytes. In order to prevent ambiguity, flash chips would actually need to
return IDs that are up to 17 or more bytes long due to JEDEC's
continuation scheme. I understand that if a manufacturer ID is located
in bank N of JEDEC's database (there are currently 16 banks), N - 1
continuation codes (7Fh) need to be added to the identification code
(comprising of manufacturer ID and device ID). However, most flash chip
manufacturers don't seem to implement this (correctly).

Signed-off-by: Ezra Buehler <ezra.buehler@husqvarnagroup.com>
Reviewed-by: Martin Kurbanov <mmkurbanov@salutedevices.com>
Tested-by: Martin Kurbanov <mmkurbanov@salutedevices.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20240125200108.24374-2-ezra@easyb.ch
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/mtd/spinand.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -169,7 +169,7 @@
struct spinand_op;
struct spinand_device;

-#define SPINAND_MAX_ID_LEN 4
+#define SPINAND_MAX_ID_LEN 5
/*
* For erase, write and read operation, we got the following timings :
* tBERS (erase) 1ms to 4ms