mtd: Workaround wrong write protect status on some xD cards

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

2 files changed, 13 insertions, 1 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 1c4823696be2..b9dc65c7253c 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/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;
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index d152bdf9161f..8bdacb885f90 100644
--- a/include/linux/mtd/nand.h
+++ b/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)