mtd: nand: add generic helpers to check, match, maximize ECC settings
authorMasahiro Yamada <yamada.masahiro@socionext.com>
Tue, 21 Nov 2017 17:38:29 +0000 (02:38 +0900)
committerMasahiro Yamada <yamada.masahiro@socionext.com>
Tue, 28 Nov 2017 15:28:59 +0000 (00:28 +0900)
commit470c29d1c28d23bdd86456bc431b8f26f8727903
tree63f650dd9f6b9f024127727db7d8409a6f774404
parent52cde35b9645e60a0c8e4040136476c4f9804110
mtd: nand: add generic helpers to check, match, maximize ECC settings

Driver are responsible for setting up ECC parameters correctly.
Those include:
  - Check if ECC parameters specified (usually by DT) are valid
  - Meet the chip's ECC requirement
  - Maximize ECC strength if NAND_ECC_MAXIMIZE flag is set

The logic can be generalized by factoring out common code.

This commit adds 3 helpers to the NAND framework:
nand_check_ecc_caps - Check if preset step_size and strength are valid
nand_match_ecc_req - Match the chip's requirement
nand_maximize_ecc - Maximize the ECC strength

To use the helpers above, a driver needs to provide:
  - Data array of supported ECC step size and strength
  - A hook that calculates ECC bytes from the combination of
    step_size and strength.

By using those helpers, code duplication among drivers will be
reduced.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[Linux commit: 2c8f8afa7f92acb07641bf95b940d384ed1d0294]
drivers/mtd/nand/nand_base.c
include/linux/mtd/nand.h