[PATCH] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation

[PATCH] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation

[Miquel Raynal]

"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@collins.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 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 44919d48d241..c459f169a904 100644
--- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
@@ -122,7 +122,7 @@ 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
-- 
2.27.0


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Re: [PATCH] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation

[Rob Herring]

On Thu, 10 Jun 2021 16:39:45 +0200, Miquel Raynal wrote:
> "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@collins.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  Documentation/devicetree/bindings/mtd/gpmc-nand.txt | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Acked-by: Rob Herring <robh@kernel.org>

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Re: [PATCH] dt-bindings: mtd: gpmc: Fix the ECC bytes vs. OOB bytes equation

[Miquel Raynal]

On Thu, 2021-06-10 at 14:39:45 UTC, Miquel Raynal wrote:
> "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@collins.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Acked-by: Rob Herring <robh@kernel.org>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next.

Miquel

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