[PATCH v1] mtd: spinand: Add support for 5-byte IDs

From: Dmitry Rokosov
Date: Thu Apr 04 2024 - 08:19:38 EST


From: Ezra Buehler <ezra.buehler@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 34a956739d295de6010cdaafeed698ccbba87ea4 ]

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).

Cc: <stable@xxxxxxxxxxxxxxx> # 6.6.23
Cc: <stable@xxxxxxxxxxxxxxx> # 6.7.11
Cc: <stable@xxxxxxxxxxxxxxx> # 6.8.2
Signed-off-by: Ezra Buehler <ezra.buehler@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Martin Kurbanov <mmkurbanov@xxxxxxxxxxxxxxxxx>
Tested-by: Martin Kurbanov <mmkurbanov@xxxxxxxxxxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20240125200108.24374-2-ezra@xxxxxxxx
Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxxxxx>
---

In the patch series [1] only one patch was marked with Fixes tag, that's
why the secon patch was not applied to 6.6.y, 6.7.y and 6.8y. It breaks
ESMT detection flow with logs:

[ 0.770730] spi-nand spi0.0: unknown raw ID c8017f7f
[ 0.772688] spi-nand: probe of spi0.0 failed with error -524

Please cherry-pick the second patch from the series to 6.6.y, 6.7.y and
6.8.y.

Links:
[1] https://lore.kernel.org/linux-mtd/20240125200108.24374-1-ezra@xxxxxxxx/

---
include/linux/mtd/spinand.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index badb4c1ac079..5c19ead60499 100644
--- 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
--
2.43.0