mtd: spi-nor: fix wrong "fully unlocked" test

commit 06586204714b7befec99e554c71687b0b40f351c upstream.

In stm_unlock(), the test to determine whether we've fully unlocked the
flash checks for the lock length to be equal to the flash size. That is
a typo/think-o -- the condition actually means the flash is completely
*locked.* We should be using the inverse condition -- that the lock
length is 0 (i.e., no protection).

The result of this bug is that we never actually turn off the Status
Register Write Disable bit, even if the flash is completely unlocked.
Now we can.

Fixes: 47b8edbf0d43 ("mtd: spi-nor: disallow further writes to SR if WP# is low")
Reported-by: Giorgio <giorgio.nicole@arcor.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index c52e45594bfd6e78775f6250314c9cf26a049e2a..a6adb2785b14986d880e51eb19f26c04e41e3c54 100644 (file)
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -661,7 +661,7 @@ static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
        status_new = (status_old & ~mask & ~SR_TB) | val;
 
        /* Don't protect status register if we're fully unlocked */
-       if (lock_len == mtd->size)
+       if (lock_len == 0)
                status_new &= ~SR_SRWD;
 
        if (!use_top)