mtd: spi-nor: Set all BP bits to one when lock_len == mtd->size

When there are more BP settings than needed for defining the protected
areas of the flash memory, most flashes will define the remaining
settings as "protect all", i.e. the equivalent of having all the BP bits
set to one. But there are flashes where the in-between BP values
are undefined (not mentioned), and only the "all bits set" is protecting
the entire memory. One such example is w25q80, where BP[2:0]=0b101 and
0b110 are not defined.

Set all the BP bits to one when lock_len == mtd->size, to treat this
special case.

Suggested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Jungseung Lee <js07.lee@samsung.com>
Reviewed-by: Michael Walle <michael@walle.cc>

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index e0021dd34bfeff11cddeed714bc29b31b7c25608..bc57b1b5ec62b28a94422c273f441088d65f4a95 100644 (file)
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1682,13 +1682,19 @@ static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
         *
         *   pow = ceil(log2(size / len)) = log2(size) - floor(log2(len))
         */
-       pow = ilog2(mtd->size) - ilog2(lock_len);
-       val = mask - (pow << SR_BP_SHIFT);
-       if (val & ~mask)
-               return -EINVAL;
-       /* Don't "lock" with no region! */
-       if (!(val & mask))
-               return -EINVAL;
+       if (lock_len == mtd->size) {
+               val = mask;
+       } else {
+               pow = ilog2(mtd->size) - ilog2(lock_len);
+               val = mask - (pow << SR_BP_SHIFT);
+
+               if (val & ~mask)
+                       return -EINVAL;
+
+               /* Don't "lock" with no region! */
+               if (!(val & mask))
+                       return -EINVAL;
+       }
 
        status_new = (status_old & ~mask & ~tb_mask) | val;