[MTD] Unlock NOR flash automatically where necessary

[Linux-MTD Mailing List]

Commit:     187ef15268e638603dea55a91fdfa29feaed6d13
Parent:     e478bec0ba0a83a48a0f6982934b6de079e7e6b3
commit 187ef15268e638603dea55a91fdfa29feaed6d13
Author:     Håvard Skinnemoen <hskinnemoen at atmel.com>
AuthorDate: Fri Sep 22 10:07:08 2006 +0100
Commit:     David Woodhouse <dwmw2 at infradead.org>
CommitDate: Fri Sep 22 10:07:08 2006 +0100

    [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 at atmel.com>
    Signed-off-by: Andrew Morton <akpm at osdl.org>
    Signed-off-by: David Woodhouse <dwmw2 at infradead.org>
---
 drivers/mtd/chips/cfi_cmdset_0002.c |    1 +
 drivers/mtd/mtdcore.c               |   10 ++++++++++
 include/mtd/mtd-abi.h               |    1 +
 3 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index a482e89..702ae4c 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->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 168d3ba..c4d26de 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 */
diff --git a/include/mtd/mtd-abi.h b/include/mtd/mtd-abi.h
index 1da3f7f..b0a67b7 100644
--- a/include/mtd/mtd-abi.h
+++ b/include/mtd/mtd-abi.h
@@ -34,6 +34,7 @@ #define MTD_DATAFLASH		6
 #define MTD_WRITEABLE		0x400	/* Device is writeable */
 #define MTD_BIT_WRITEABLE	0x800	/* Single bits can be flipped */
 #define MTD_NO_ERASE		0x1000	/* No erase necessary */
+#define MTD_STUPID_LOCK		0x2000	/* Always locked after reset */
 
 // Some common devices / combinations of capabilities
 #define MTD_CAP_ROM		0