[PATCH v3 2/2] mtd: rawnand: brcmnand: improve hamming oob layout

[Álvaro Fernández Rojas]

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

Fixes: ef5eeea6e911 ("mtd: nand: brcm: switch to mtd_ooblayout_ops")
Signed-off-by: Álvaro Fernández Rojas <nolt...@gmail.com>
---
 v3: invert patch order
 v2: keep original comment and fix correctly skip byte 6 for small-page nand

 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 37 ++++++++++++------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c 
b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 1c1070111ebc..0a1d76fde37b 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -1100,33 +1100,32 @@ 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--;
-                       }
+               /*
+                * 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;
+               } else {
+                       oobregion->offset = 0;
+                       next--;
                }
        }
 
+       oobregion->length = next - oobregion->offset;
+
        return 0;
 }
 
-- 
2.26.2