On 2018-05-07 13:46, Boris Brezillon wrote:
On Thu, 3 May 2018 17:50:28 +0530
Abhishek Sahu <absahu@xxxxxxxxxxxxxx> wrote:
commit 2c8f8afa7f92 ("mtd: nand: add generic helpers to check,
match, maximize ECC settings") provides generic helpers which
drivers can use for setting up ECC parameters.
Since same board can have different ECC strength nand chips so
following is the logic for setting up ECC strength and ECC step
size, which can be used by most of the drivers.
1. If both ECC step size and ECC strength are already set
(usually by DT) then just check whether this setting
is supported by NAND controller.
2. If NAND_ECC_MAXIMIZE is set, then select maximum ECC strength
supported by NAND controller.
3. Otherwise, try to match the ECC step size and ECC strength closest
to the chip's requirement. If available OOB size can't fit the chip
requirement then select maximum ECC strength which can be fit with
available OOB size with warning.
This patch introduces nand_ecc_param_setup function which calls the
required helper functions for the above logic. The drivers can use
this single function instead of calling the 3 helper functions
individually.
CC: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Signed-off-by: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>
---
* Changes from v1:
NEW PATCH
drivers/mtd/nand/raw/nand_base.c | 42
++++++++++++++++++++++++++++++++++++++++
include/linux/mtd/rawnand.h | 3 +++
2 files changed, 45 insertions(+)
diff --git a/drivers/mtd/nand/raw/nand_base.c
b/drivers/mtd/nand/raw/nand_base.c
index 72f3a89..dd7a984 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -6249,6 +6249,48 @@ int nand_maximize_ecc(struct nand_chip *chip,
}
EXPORT_SYMBOL_GPL(nand_maximize_ecc);
+/**
+ * nand_ecc_param_setup - Set the ECC strength and ECC step size
+ * @chip: nand chip info structure
+ * @caps: ECC engine caps info structure
+ * @oobavail: OOB size that the ECC engine can use
+ *
+ * Choose the ECC strength according to following logic
+ *
+ * 1. If both ECC step size and ECC strength are already set (usually
by DT)
+ * then check if it is supported by this controller.
+ * 2. If NAND_ECC_MAXIMIZE is set, then select maximum ECC strength.
+ * 3. Otherwise, try to match the ECC step size and ECC strength
closest
+ * to the chip's requirement. If available OOB size can't fit the
chip
+ * requirement then fallback to the maximum ECC step size and ECC
strength
+ * and print the warning.
+ *
+ * On success, the chosen ECC settings are set.
+ */
+int nand_ecc_param_setup(struct nand_chip *chip,
+ const struct nand_ecc_caps *caps, int oobavail)
Can we rename this function "nand_ecc_choose_conf()".
Thanks Boris.
I will rename this function.
Regards,
Abhishek
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