mtd: nand: add NAND_NEED_SCRAMBLING option flag

Some MLC NANDs are sensitive to repeated patterns and require data to be
scrambled in order to limit the number of bitflips.
Add a new flag to let the NAND controller know about this constraint.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index bdd68e2..a13dfd5 100644 (file)
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -168,6 +168,12 @@ typedef enum {
 /* Device supports subpage reads */
 #define NAND_SUBPAGE_READ      0x00001000
 
+/*
+ * Some MLC NANDs need data scrambling to limit bitflips caused by repeated
+ * patterns.
+ */
+#define NAND_NEED_SCRAMBLING   0x00002000
+
 /* Options valid for Samsung large page devices */
 #define NAND_SAMSUNG_LP_OPTIONS NAND_CACHEPRG