[PATCH 4.9 19/21] mtd: nand: pxa3xx: Fix READOOB implementation

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Boris Brezillon <boris.brezillon@free-electrons.com>

commit fee4380f368e84ed216b62ccd2fbc4126f2bf40b upstream.

In the current driver, OOB bytes are accessed in raw mode, and when a
page access is done with NDCR_SPARE_EN set and NDCR_ECC_EN cleared, the
driver must read the whole spare area (64 bytes in case of a 2k page,
16 bytes for a 512 page). The driver was only reading the free OOB
bytes, which was leaving some unread data in the FIFO and was somehow
leading to a timeout.

We could patch the driver to read ->spare_size + ->ecc_size instead of
just ->spare_size when READOOB is requested, but we'd better make
in-band and OOB accesses consistent.
Since the driver is always accessing in-band data in non-raw mode (with
the ECC engine enabled), we should also access OOB data in this mode.
That's particularly useful when using the BCH engine because in this
mode the free OOB bytes are also ECC protected.

Fixes: 43bcfd2bb24a ("mtd: nand: pxa3xx: Add driver-specific ECC BCH support")
Reported-by: Sean Nyekjær <sean.nyekjaer@prevas.dk>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Tested-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mtd/nand/pxa3xx_nand.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -950,6 +950,7 @@ static void prepare_start_command(struct
 
 	switch (command) {
 	case NAND_CMD_READ0:
+	case NAND_CMD_READOOB:
 	case NAND_CMD_PAGEPROG:
 		info->use_ecc = 1;
 		break;