mtd: nand: refactor BB marker detection

Some level of support for various scanning locations was already built in,
but this required clean-up. First, BB marker location cannot be determined
_only_ by the page size. Instead, I implemented some heuristic detection
based on data sheets from various manufacturers (all found in
nand_base.c:nand_get_flash_type()).

Second, once these options were identified, they were not handled properly
by nand_bbt.c:nand_default_bbt(). I updated the static nand_bbt_desc structs
to reflect the need for more combinations of detection. The memory allocation
here probably needs to be done dynamically in the very near future (see next
patches).

Signed-off-by: Brian Norris <norris@broadcom.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 38 insertions, 7 deletions

diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 71d83be24ff6..ec1700eaf198 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -1093,29 +1093,50 @@ int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 
 static struct nand_bbt_descr smallpage_memorybased = {
-        .options = NAND_BBT_SCAN2NDPAGE,
-        .offs = 5,
+        .options = 0,
+        .offs = NAND_SMALL_BADBLOCK_POS,
         .len = 1,
         .pattern = scan_ff_pattern
 };
 
+static struct nand_bbt_descr smallpage_scan2nd_memorybased = {
+        .options = NAND_BBT_SCAN2NDPAGE,
+        .offs = NAND_SMALL_BADBLOCK_POS,
+        .len = 2,
+        .pattern = scan_ff_pattern
+};
+
 static struct nand_bbt_descr largepage_memorybased = {
         .options = 0,
-        .offs = 0,
+        .offs = NAND_LARGE_BADBLOCK_POS,
+        .len = 1,
+        .pattern = scan_ff_pattern
+};
+
+static struct nand_bbt_descr largepage_scan2nd_memorybased = {
+        .options = NAND_BBT_SCAN2NDPAGE,
+        .offs = NAND_LARGE_BADBLOCK_POS,
         .len = 2,
         .pattern = scan_ff_pattern
 };
 
+static struct nand_bbt_descr lastpage_memorybased = {
+        .options = NAND_BBT_SCANLASTPAGE,
+        .offs = 0,
+        .len = 1,
+        .pattern = scan_ff_pattern
+};
+
 static struct nand_bbt_descr smallpage_flashbased = {
         .options = NAND_BBT_SCAN2NDPAGE,
-        .offs = 5,
+        .offs = NAND_SMALL_BADBLOCK_POS,
         .len = 1,
         .pattern = scan_ff_pattern
 };
 
 static struct nand_bbt_descr largepage_flashbased = {
         .options = NAND_BBT_SCAN2NDPAGE,
-        .offs = 0,
+        .offs = NAND_LARGE_BADBLOCK_POS,
         .len = 2,
         .pattern = scan_ff_pattern
 };
@@ -1197,8 +1218,18 @@ int nand_default_bbt(struct mtd_info *mtd)
                 this->bbt_td = NULL;
                 this->bbt_md = NULL;
                 if (!this->badblock_pattern) {
-                        this->badblock_pattern = (mtd->writesize > 512) ?
-                            &largepage_memorybased : &smallpage_memorybased;
+                        if (this->options & NAND_BBT_SCANLASTPAGE)
+                                this->badblock_pattern = &lastpage_memorybased;
+                        else if (this->options & NAND_BBT_SCAN2NDPAGE)
+                                this->badblock_pattern = this->badblockpos ==
+                                        NAND_SMALL_BADBLOCK_POS ?
+                                        &smallpage_scan2nd_memorybased :
+                                        &largepage_scan2nd_memorybased;
+                        else
+                                this->badblock_pattern = this->badblockpos ==
+                                        NAND_SMALL_BADBLOCK_POS ?
+                                        &smallpage_memorybased :
+                                        &largepage_memorybased;
                 }
         }
         return nand_scan_bbt(mtd, this->badblock_pattern);