From: Stefan Agner stefan.agner@toradex.com
Add support for minimum ECC strength supported by the NAND chip. This aligns with the behavior when using the fsl,use-minimum-ecc device tree property in Linux.
Signed-off-by: Stefan Agner stefan.agner@toradex.com ---
Changes in v2: None
drivers/mtd/nand/Kconfig | 8 +++++ drivers/mtd/nand/mxs_nand.c | 71 ++++++++++++++++++++++++++++++++++++--------- 2 files changed, 65 insertions(+), 14 deletions(-)
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig index 9fea8fbd1f..51577ddc10 100644 --- a/drivers/mtd/nand/Kconfig +++ b/drivers/mtd/nand/Kconfig @@ -147,6 +147,14 @@ config NAND_MXS This enables NAND driver for the NAND flash controller on the MXS processors.
+if NAND_MXS + +config NAND_MXS_USE_MINIMUM_ECC + bool "Use minimum ECC strength supported by the controller" + default false + +endif + config NAND_ZYNQ bool "Support for Zynq Nand controller" select SYS_NAND_SELF_INIT diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c index 2d84bab717..cdd5a86fe2 100644 --- a/drivers/mtd/nand/mxs_nand.c +++ b/drivers/mtd/nand/mxs_nand.c @@ -211,11 +211,52 @@ static inline int mxs_nand_calc_mark_offset(struct bch_geometry *geo, return 0; }
+static inline unsigned int mxs_nand_max_ecc_strength_supported(void) +{ + /* Refer to Chapter 17 for i.MX6DQ, Chapter 18 for i.MX6SX */ + if (is_mx6sx() || is_mx7()) + return 62; + else + return 40; +} + +static inline int mxs_nand_calc_ecc_layout_by_info(struct bch_geometry *geo, + struct mtd_info *mtd) +{ + struct nand_chip *chip = mtd_to_nand(mtd); + + if (!(chip->ecc_strength_ds > 0 && chip->ecc_step_ds > 0)) + return -ENOTSUPP; + + switch (chip->ecc_step_ds) { + case SZ_512: + geo->gf_len = 13; + break; + case SZ_1K: + geo->gf_len = 14; + break; + default: + return -EINVAL; + } + + geo->ecc_chunk_size = chip->ecc_step_ds; + geo->ecc_strength = round_up(chip->ecc_strength_ds, 2); + + /* Keep the C >= O */ + if (geo->ecc_chunk_size < mtd->oobsize) + return -EINVAL; + + if (geo->ecc_strength > mxs_nand_max_ecc_strength_supported()) + return -EINVAL; + + geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size; + + return 0; +} + static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo, struct mtd_info *mtd) { - unsigned int max_ecc_strength_supported; - /* The default for the length of Galois Field. */ geo->gf_len = 13;
@@ -235,12 +276,6 @@ static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo,
geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size;
- /* Refer to Chapter 17 for i.MX6DQ, Chapter 18 for i.MX6SX */ - if (is_mx6sx() || is_mx7()) - max_ecc_strength_supported = 62; - else - max_ecc_strength_supported = 40; - /* * Determine the ECC layout with the formula: * ECC bits per chunk = (total page spare data bits) / @@ -252,10 +287,8 @@ static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo, geo->ecc_strength = ((mtd->oobsize - MXS_NAND_METADATA_SIZE) * 8) / (geo->gf_len * geo->ecc_chunk_count);
- geo->ecc_strength = min(round_down(geo->ecc_strength, 2), max_ecc_strength_supported); - - if (mxs_nand_calc_mark_offset(geo, mtd->writesize) < 0) - return -EINVAL; + geo->ecc_strength = min(round_down(geo->ecc_strength, 2), + mxs_nand_max_ecc_strength_supported());
return 0; } @@ -1006,9 +1039,19 @@ static int mxs_nand_setup_ecc(struct mtd_info *mtd) struct bch_geometry *geo = &nand_info->bch_geometry; struct mxs_bch_regs *bch_regs = (struct mxs_bch_regs *)MXS_BCH_BASE; uint32_t tmp; + int ret = -ENOTSUPP;
- if (mxs_nand_calc_ecc_layout(geo, mtd)) - return -EINVAL; +#ifdef CONFIG_NAND_MXS_USE_MINIMUM_ECC + ret = mxs_nand_calc_ecc_layout_by_info(geo, mtd); +#endif + + if (ret == -ENOTSUPP) + ret = mxs_nand_calc_ecc_layout(geo, mtd); + + if (ret) + return ret; + + mxs_nand_calc_mark_offset(geo, mtd->writesize);
/* Configure BCH and set NFC geometry */ mxs_reset_block(&bch_regs->hw_bch_ctrl_reg);