Commit bb415dff authored by Xiaolei Li's avatar Xiaolei Li Committed by Boris Brezillon
Browse files

dt-bindings: mtd: mtk-nand: Update properties description 



Update ecc step size, ecc strength, and parity bits supported on
each MTK NAND controller.

Signed-off-by: default avatarXiaolei Li <xiaolei.li@mediatek.com>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
parent 4baf6819

Documentation/devicetree/bindings/mtd/mtk-nand.txt

+19 −5
Original line number Diff line number Diff line
@@ -50,14 +50,19 @@ Optional: 
- nand-on-flash-bbt:	Store BBT on NAND Flash.

- nand-ecc-mode:	the NAND ecc mode (check driver for supported modes)

- nand-ecc-step-size:	Number of data bytes covered by a single ECC step.

			valid values: 512 and 1024.

			valid values:

			512 and 1024 on mt2701 and mt2712.

			512 only on mt7622.

			1024 is recommended for large page NANDs.

- nand-ecc-strength:	Number of bits to correct per ECC step.

			The valid values that the controller supports are: 4, 6,

			8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, 40, 44,

			48, 52, 56, 60.

			The valid values that each controller supports:

			mt2701: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28,

				32, 36, 40, 44, 48, 52, 56, 60.

			mt2712: 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28,

				32, 36, 40, 44, 48, 52, 56, 60, 68, 72, 80.

			mt7622: 4, 6, 8, 10, 12, 14, 16.

			The strength should be calculated as follows:

			E = (S - F) * 8 / 14

			E = (S - F) * 8 / B

			S = O / (P / Q)

				E :	nand-ecc-strength.

				S :	spare size per sector.
@@ -66,6 +71,15 @@ Optional: 
				O :	oob size.

				P :	page size.

				Q :	nand-ecc-step-size.

				B :	number of parity bits needed to correct

					1 bitflip.

					According to MTK NAND controller design,

					this number depends on max ecc step size

					that MTK NAND controller supports.

					If max ecc step size supported is 1024,

					then it should be always 14. And if max

					ecc step size is 512, then it should be

					always 13.

			If the result does not match any one of the listed

			choices above, please select the smaller valid value from

			the list.

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