Rework the routine that returns a pointer to the table of software ECC

byte positions within the OOB area to support chips with unusual OOB
sizes such as 218 or 224 bytes.

The table for 128 byte OOB works for these but it assumes 3 bytes of ECC
per 256 byte block, and in the case of an ONFI chip the params page may
ask for something different.  In other words, this is better but not
yet perfect.

1 files changed, 16 insertions, 17 deletions

diff --git a/sys/dev/nand/nand.c b/sys/dev/nand/nand.c
index 902ff79..fb83e67 100644
--- a/sys/dev/nand/nand.c
+++ b/sys/dev/nand/nand.c
@@ -309,23 +309,22 @@ nand_get_chip_param(struct nand_chip *chip, struct chip_param_io *param)
 static uint16_t *
 default_software_ecc_positions(struct nand_chip *chip)
 {
-	struct nand_ecc_data *eccd;
-
-	eccd = &chip->nand->ecc;
-
-	if (eccd->eccpositions)
-		return (eccd->eccpositions);
-
-	switch (chip->chip_geom.oob_size) {
-	case 16:
-		return ((uint16_t *)&default_software_ecc_positions_16);
-	case 64:
-		return ((uint16_t *)&default_software_ecc_positions_64);
-	case 128:
-		return ((uint16_t *)&default_software_ecc_positions_128);
-	default:
-		return (NULL); /* No ecc bytes positions defs available */
-	}
+	/* If positions have been set already, use them. */
+	if (chip->nand->ecc.eccpositions)
+		return (chip->nand->ecc.eccpositions);
+
+	/*
+	 * XXX Note that the following logic isn't really sufficient, especially
+	 * in the ONFI case where the number of ECC bytes can be dictated by
+	 * values in the parameters page, and that could lead to needing more
+	 * byte positions than exist within the tables of software-ecc defaults.
+	 */
+	if (chip->chip_geom.oob_size >= 128)
+		return (default_software_ecc_positions_128);
+	if (chip->chip_geom.oob_size >= 64)
+		return (default_software_ecc_positions_64);
+	else if (chip->chip_geom.oob_size >= 16)
+		return (default_software_ecc_positions_16);
 
 	return (NULL);
 }