mtd: nand: pxa3xx: make ECC configuration checks more explicit

The Armada BCH configuration in this driver uses one of the two
following ECC schemes:

 16-bit correction per 2048 bytes
 16-bit correction per 1024 bytes

These are sufficient for mapping to the 4-bit per 512-bytes and 8-bit
per 512-bytes (respectively) minimum correctability requirements of many
common NAND.

The current code only checks for the required strength (4-bit or 8-bit)
without checking the ECC step size that is associated with that strength
(and simply assumes it is 512). While that is often a safe assumption to
make, let's make it explicit, since we have that information.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Daniel Mack <zonque@gmail.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index f00ce27f61d0..8f38abdb3310 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -1360,9 +1360,13 @@ static int pxa_ecc_init(struct pxa3xx_nand_info *info,
 
 static int armada370_ecc_init(struct pxa3xx_nand_info *info,
                               struct nand_ecc_ctrl *ecc,
-                              int strength, int page_size)
+                              int strength, int ecc_stepsize, int page_size)
 {
-        if (strength == 4 && page_size == 4096) {
+        /*
+         * Required ECC: 4-bit correction per 512 bytes
+         * Select: 16-bit correction per 2048 bytes
+         */
+        if (strength == 4 && ecc_stepsize == 512 && page_size == 4096) {
                 info->ecc_bch = 1;
                 info->chunk_size = 2048;
                 info->spare_size = 32;
@@ -1373,7 +1377,11 @@ static int armada370_ecc_init(struct pxa3xx_nand_info *info,
                 ecc->strength = 16;
                 return 1;
 
-        } else if (strength == 8 && page_size == 4096) {
+        /*
+         * Required ECC: 8-bit correction per 512 bytes
+         * Select: 16-bit correction per 1024 bytes
+         */
+        } else if (strength == 8 && ecc_stepsize == 512 && page_size == 4096) {
                 info->ecc_bch = 1;
                 info->chunk_size = 1024;
                 info->spare_size = 0;
@@ -1481,6 +1489,7 @@ KEEP_CONFIG:
         if (info->variant == PXA3XX_NAND_VARIANT_ARMADA370)
                 ret = armada370_ecc_init(info, &chip->ecc,
                                    chip->ecc_strength_ds,
+                                   chip->ecc_step_ds,
                                    mtd->writesize);
         else
                 ret = pxa_ecc_init(info, &chip->ecc,