[MTD] Unlock NOR flash automatically where necessary

Introduce the MTD_STUPID_LOCK flag which indicates that the flash chip is
always locked after power-up, so all sectors need to be unlocked before it
is usable.

If this flag is set, and the chip provides an unlock() operation,
mtd_add_device will unlock the whole MTD device if it's writeable.  This
means that non-writeable partitions will stay locked.

Set MTD_STUPID_LOCK in fixup_use_atmel_lock() so that these chips will work
as expected.

Signed-off-by: Håvard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

2 files changed, 11 insertions, 0 deletions

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index a482e8922de1..702ae4cd8691 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -212,6 +212,7 @@ static void fixup_use_atmel_lock(struct mtd_info *mtd, void *param)
 {
         mtd->lock = cfi_atmel_lock;
         mtd->unlock = cfi_atmel_unlock;
+        mtd->flags |= MTD_STUPID_LOCK;
 }
 
 static struct cfi_fixup cfi_fixup_table[] = {
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 168d3ba063c3..c4d26de74349 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -57,6 +57,16 @@ int add_mtd_device(struct mtd_info *mtd)
                         mtd->index = i;
                         mtd->usecount = 0;
 
+                        /* Some chips always power up locked. Unlock them now */
+                        if ((mtd->flags & MTD_WRITEABLE)
+                            && (mtd->flags & MTD_STUPID_LOCK) && mtd->unlock) {
+                                if (mtd->unlock(mtd, 0, mtd->size))
+                                        printk(KERN_WARNING
+                                               "%s: unlock failed, "
+                                               "writes may not work\n",
+                                               mtd->name);
+                        }
+
                         DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name);
                         /* No need to get a refcount on the module containing
                            the notifier, since we hold the mtd_table_mutex */