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>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 1c48236..b9dc65c 100644 (file)
--- 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 d152bdf..8bdacb8 100644 (file)
--- 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)