[PATCH 1/3] mtd: nand: add support for "nand-ecc-algo" DT property

Rafał Miłecki
2016-04-22T11:23:28Z

So far it was only possible to specify ECC algorithm using "soft" and
"soft_bch" values of nand-ecc-mode prop. There wasn't a way to specify
it for a hardware ECC mode.

Now that we have independent field in NAND subsystem for storing info
about ECC algorithm we may also add support for this new DT property.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
Documentation/devicetree/bindings/mtd/nand.txt | 2 ++
drivers/mtd/nand/nand_base.c | 20 +++++++++++++-------
2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
index a17662b..5ac4ab7 100644
--- a/Documentation/devicetree/bindings/mtd/nand.txt
+++ b/Documentation/devicetree/bindings/mtd/nand.txt
@@ -22,6 +22,8 @@ Optional NAND chip properties:
- nand-ecc-mode : String, operation mode of the NAND ecc mode.
Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first",
"soft_bch".
+- nand-ecc-algo: string, algorithm of NAND ECC.
+ Supported values are: "hamming", "bch".
- nand-bus-width : 8 or 16 bus width if not present 8
- nand-on-flash-bbt: boolean to enable on flash bbt option if not present false

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 7bc37b4..a5417a0 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -4003,17 +4003,23 @@ static int of_get_nand_ecc_mode(struct device_node *np)
return -ENODEV;
}

+static const char * const nand_ecc_algos[] = {
+ [NAND_ECC_HAMMING] = "hamming",
+ [NAND_ECC_BCH] = "bch",
+};
+
static int of_get_nand_ecc_algo(struct device_node *np)
{
const char *pm;
- int err;
+ int err, i;

- /*
- * TODO: Read ECC algo OF property and map it to enum nand_ecc_algo.
- * It's not implemented yet as currently NAND subsystem ignores
- * algorithm explicitly set this way. Once it's handled we should
- * document & support new property.
- */
+ err = of_property_read_string(np, "nand-ecc-algo", &pm);
+ if (!err) {
+ for (i = 0; i < ARRAY_SIZE(nand_ecc_algos); i++)
+ if (!strcasecmp(pm, nand_ecc_algos[i]))
+ return i;
+ return -ENODEV;
+ }

/*
* For backward compatibility we also read "nand-ecc-mode" checking
--
1.8.4.5