[PATCH AUTOSEL 4.9 1/4] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation

From: Sasha Levin
Date: Sat Sep 11 2021 - 09:22:55 EST


From: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>

[ Upstream commit 778cb8e39f6ec252be50fc3850d66f3dcbd5dd5a ]

"PAGESIZE / 512" is the number of ECC chunks.
"ECC_BYTES" is the number of bytes needed to store a single ECC code.
"2" is the space reserved by the bad block marker.

"2 + (PAGESIZE / 512) * ECC_BYTES" should of course be lower or equal
than the total number of OOB bytes, otherwise it won't fit.

Fix the equation by substituting s/>=/<=/.

Suggested-by: Ryan J. Barnett <ryan.barnett@xxxxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20210610143945.3504781-1-miquel.raynal@xxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
Documentation/devicetree/bindings/mtd/gpmc-nand.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
index 174f68c26c1b..34981b98d807 100644
--- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
@@ -123,7 +123,7 @@ on various other factors also like;
so the device should have enough free bytes available its OOB/Spare
area to accommodate ECC for entire page. In general following expression
helps in determining if given device can accommodate ECC syndrome:
- "2 + (PAGESIZE / 512) * ECC_BYTES" >= OOBSIZE"
+ "2 + (PAGESIZE / 512) * ECC_BYTES" <= OOBSIZE"
where
OOBSIZE number of bytes in OOB/spare area
PAGESIZE number of bytes in main-area of device page
--
2.30.2