[PATCH v3 2/5] mtd: rawnand: nand_base: Handle algorithm selection

[Linus Walleij]

For BRCMNAND with 1-bit BCH ECC (BCH-1) such as used on the
D-Link DIR-885L and DIR-890L routers, we need to explicitly
select the ECC like this in the device tree:

  nand-ecc-algo = "bch";
  nand-ecc-strength = <1>;
  nand-ecc-step-size = <512>;

This is handled by the Linux kernel but U-Boot core does
not respect this. Fix it up by parsing the algorithm and
preserve the behaviour using this property to select
software BCH as far as possible.

Reviewed-by: Michael Trimarchi <mich...@amarulasolutions.com>
Acked-by: William Zhang <william.zh...@broadcom.com>
Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
---
ChangeLog v2->v3:
- Collect review tags from Michael and William
- Resend with the NorthStar enablement patches
ChangeLog v1->v2:
- Drop pointless check for ecc_algo >= 0, it is always
  >= 0.
---
 drivers/mtd/nand/raw/nand_base.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 9eba360d55f3..c173fd09237a 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -4487,6 +4487,7 @@ EXPORT_SYMBOL(nand_detect);
 static int nand_dt_init(struct mtd_info *mtd, struct nand_chip *chip, ofnode 
node)
 {
        int ret, ecc_mode = -1, ecc_strength, ecc_step;
+       int ecc_algo = NAND_ECC_UNKNOWN;
        const char *str;
 
        ret = ofnode_read_s32_default(node, "nand-bus-width", -1);
@@ -4512,10 +4513,13 @@ static int nand_dt_init(struct mtd_info *mtd, struct 
nand_chip *chip, ofnode nod
                        ecc_mode = NAND_ECC_SOFT_BCH;
        }
 
-       if (ecc_mode == NAND_ECC_SOFT) {
-               str = ofnode_read_string(node, "nand-ecc-algo");
-               if (str && !strcmp(str, "bch"))
+       str = ofnode_read_string(node, "nand-ecc-algo");
+       if (str && !strcmp(str, "bch")) {
+               ecc_algo = NAND_ECC_BCH;
+               if (ecc_mode == NAND_ECC_SOFT)
                        ecc_mode = NAND_ECC_SOFT_BCH;
+       } else if (!strcmp(str, "hamming")) {
+               ecc_algo = NAND_ECC_HAMMING;
        }
 
        ecc_strength = ofnode_read_s32_default(node,
@@ -4529,6 +4533,8 @@ static int nand_dt_init(struct mtd_info *mtd, struct 
nand_chip *chip, ofnode nod
                return -EINVAL;
        }
 
+       chip->ecc.algo = ecc_algo;
+
        if (ecc_mode >= 0)
                chip->ecc.mode = ecc_mode;
 
-- 
2.39.2