mtd: Workaround wrong write protect status on some xD cards

Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/nand_base.c

@@ -434,6 +434,11 @@ static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs)
 static int nand_check_wp(struct mtd_info *mtd)
 {
 	struct nand_chip *chip = mtd->priv;
+
+	/* broken xD cards report WP despite being writable */
+	if (chip->options & NAND_BROKEN_XD)
+		return 0;
+
 	/* Check the WP bit */
 	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
 	return (chip->read_byte(mtd) & NAND_STATUS_WP) ? 0 : 1;
@@ -3175,7 +3180,8 @@ int nand_scan_tail(struct mtd_info *mtd)
 
 	/* Fill in remaining MTD driver data */
 	mtd->type = MTD_NANDFLASH;
-	mtd->flags = MTD_CAP_NANDFLASH;
+	mtd->flags = (chip->options & NAND_ROM) ? MTD_CAP_ROM :
+						MTD_CAP_NANDFLASH;
 	mtd->erase = nand_erase;
 	mtd->point = NULL;
 	mtd->unpoint = NULL;

include/linux/mtd/nand.h

@@ -182,6 +182,12 @@ typedef enum {
 /* Chip does not allow subpage writes */
 #define NAND_NO_SUBPAGE_WRITE	0x00000200
 
+/* Device is one of 'new' xD cards that expose fake nand command set */
+#define NAND_BROKEN_XD		0x00000400
+
+/* Device behaves just like nand, but is readonly */
+#define NAND_ROM		0x00000800
+
 /* Options valid for Samsung large page devices */
 #define NAND_SAMSUNG_LP_OPTIONS \
 	(NAND_NO_PADDING | NAND_CACHEPRG | NAND_COPYBACK)