[PATCH v2] mtd: parsers: bcm47xxpart: Fix halfblock reads

[Linus Walleij]

There is some code in the parser that tries to read 0x8000
bytes into a block to "read in the middle" of the block. Well
that only works if the block is also 0x10000 bytes all the time,
else we get these parse errors as we reach the end of the flash:

spi-nor spi0.0: mx25l1606e (2048 Kbytes)
mtd_read error while parsing (offset: 0x200000): -22
mtd_read error while parsing (offset: 0x201000): -22
(...)

Fix the code to do what I think was intended.

Cc: stable at vger.kernel.org
Fixes: f0501e81fbaa ("mtd: bcm47xxpart: alternative MAGIC for board_data partition")
Cc: Rafał Miłecki <zajec5 at gmail.com>
Cc: Florian Fainelli <f.fainelli at gmail.com>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v1->v2:
- Add some fixes and stable tags.
---
 drivers/mtd/parsers/bcm47xxpart.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/parsers/bcm47xxpart.c b/drivers/mtd/parsers/bcm47xxpart.c
index 50fcf4c2174b..13daf9bffd08 100644
--- a/drivers/mtd/parsers/bcm47xxpart.c
+++ b/drivers/mtd/parsers/bcm47xxpart.c
@@ -233,11 +233,11 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 		}
 
 		/* Read middle of the block */
-		err = mtd_read(master, offset + 0x8000, 0x4, &bytes_read,
+		err = mtd_read(master, offset + (blocksize / 2), 0x4, &bytes_read,
 			       (uint8_t *)buf);
 		if (err && !mtd_is_bitflip(err)) {
 			pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
-			       offset + 0x8000, err);
+			       offset + (blocksize / 2), err);
 			continue;
 		}
 
-- 
2.34.1