mtd: rawnand: brcmnand: improve hamming oob layout

The current code generates 8 oob sections:
S1	1-5
ECC	6-8
S2	9-15
S3	16-21
ECC	22-24
S4	25-31
S5	32-37
ECC	38-40
S6	41-47
S7	48-53
ECC	54-56
S8	57-63

Change it by merging continuous sections:
S1	1-5
ECC	6-8
S2	9-21
ECC	22-24
S3	25-37
ECC	38-40
S4	41-53
ECC	54-56
S5	57-63

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200512075733.745374-3-noltari@gmail.com

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index cfd22023cfcb6ac3247fe5f2bd059c7d1b88a9a6..ede7cb95fe715bbcc2fd1ba1538e76bc16c2b490 100644 (file)
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -1099,33 +1099,30 @@ static int brcmnand_hamming_ooblayout_free(struct mtd_info *mtd, int section,
        struct brcmnand_cfg *cfg = &host->hwcfg;
        int sas = cfg->spare_area_size << cfg->sector_size_1k;
        int sectors = cfg->page_size / (512 << cfg->sector_size_1k);
+       u32 next;
 
-       if (section >= sectors * 2)
+       if (section > sectors)
                return -ERANGE;
 
-       oobregion->offset = (section / 2) * sas;
+       next = (section * sas);
+       if (section < sectors)
+               next += 6;
 
-       if (section & 1) {
-               oobregion->offset += 9;
-               oobregion->length = 7;
+       if (section) {
+               oobregion->offset = ((section - 1) * sas) + 9;
        } else {
-               oobregion->length = 6;
-
-               /* First sector of each page may have BBI */
-               if (!section) {
-                       /*
-                        * Small-page NAND use byte 6 for BBI while large-page
-                        * NAND use bytes 0 and 1.
-                        */
-                       if (cfg->page_size > 512) {
-                               oobregion->offset += 2;
-                               oobregion->length -= 2;
-                       } else {
-                               oobregion->length--;
-                       }
+               if (cfg->page_size > 512) {
+                       /* Large page NAND uses first 2 bytes for BBI */
+                       oobregion->offset = 2;
+               } else {
+                       /* Small page NAND uses last byte before ECC for BBI */
+                       oobregion->offset = 0;
+                       next--;
                }
        }
 
+       oobregion->length = next - oobregion->offset;
+
        return 0;
 }