[PATCH 4.16 41/72] mtd: rawnand: Make sure we wait tWB before polling the STATUS reg

[Greg Kroah-Hartman]

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

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

From: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>

commit 3057fcef385348fe85173f1b0c824d89f1176f72 upstream.

NAND chips require a bit of time to take the NAND operation into
account and set the BUSY bit in the STATUS reg. Make sure we don't poll
the STATUS reg too early in nand_soft_waitrdy().

Fixes: 8878b126df76 ("mtd: nand: add ->exec_op() implementation")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mtd/nand/nand_base.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -707,12 +707,17 @@ static void nand_wait_status_ready(struc
  */
 int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms)
 {
+	const struct nand_sdr_timings *timings;
 	u8 status = 0;
 	int ret;
 
 	if (!chip->exec_op)
 		return -ENOTSUPP;
 
+	/* Wait tWB before polling the STATUS reg. */
+	timings = nand_get_sdr_timings(&chip->data_interface);
+	ndelay(PSEC_TO_NSEC(timings->tWB_max));
+
 	ret = nand_status_op(chip, NULL);
 	if (ret)
 		return ret;