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>
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 8b3607bd..568f53e 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -482,6 +482,30 @@
}
/**
+ * struct nand_ecc_step_info - ECC step information of ECC engine
+ * @stepsize: data bytes per ECC step
+ * @strengths: array of supported strengths
+ * @nstrengths: number of supported strengths
+ */
+struct nand_ecc_step_info {
+ int stepsize;
+ const int *strengths;
+ int nstrengths;
+};
+
+/**
+ * struct nand_ecc_caps - capability of ECC engine
+ * @stepinfos: array of ECC step information
+ * @nstepinfos: number of ECC step information
+ * @calc_ecc_bytes: driver's hook to calculate ECC bytes per step
+ */
+struct nand_ecc_caps {
+ const struct nand_ecc_step_info *stepinfos;
+ int nstepinfos;
+ int (*calc_ecc_bytes)(int step_size, int strength);
+};
+
+/**
* struct nand_ecc_ctrl - Control structure for ECC
* @mode: ECC mode
* @algo: ECC algorithm
@@ -1246,6 +1270,15 @@
void *extraoob, int extraooblen,
int threshold);
+int nand_check_ecc_caps(struct nand_chip *chip,
+ const struct nand_ecc_caps *caps, int oobavail);
+
+int nand_match_ecc_req(struct nand_chip *chip,
+ const struct nand_ecc_caps *caps, int oobavail);
+
+int nand_maximize_ecc(struct nand_chip *chip,
+ const struct nand_ecc_caps *caps, int oobavail);
+
/* Default write_oob implementation */
int nand_write_oob_std(struct mtd_info *mtd, struct nand_chip *chip, int page);