[PATCH 4.17 18/67] mtd: spi-nor: cadence-quadspi: Fix direct mode write timeouts

[Greg Kroah-Hartman]

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

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

From: Vignesh R <vigne...@ti.com>

commit aa7eee8a143a7e8b530eb1e75fb86cae793d1e21 upstream.

Sometimes when writing large size files to flash in direct/memory mapped
mode, it is seen that flash write enable command times out with error:
[  503.146293] cadence-qspi 47040000.ospi: Flash command execution timed out.

This is because, we need to make sure previous direct write operation
is complete by polling for IDLE bit in CONFIG_REG before starting the
next operation.

Fix this by polling for IDLE bit after memory mapped write.

Fixes: a27f2eaf2b27 ("mtd: spi-nor: cadence-quadspi: Add support for direct 
access mode")
Cc: sta...@vger.kernel.org
Signed-off-by: Vignesh R <vigne...@ti.com>
Reviewed-by: Marek Vasut <marek.va...@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezil...@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/mtd/spi-nor/cadence-quadspi.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -920,10 +920,12 @@ static ssize_t cqspi_write(struct spi_no
        if (ret)
                return ret;
 
-       if (f_pdata->use_direct_mode)
+       if (f_pdata->use_direct_mode) {
                memcpy_toio(cqspi->ahb_base + to, buf, len);
-       else
+               ret = cqspi_wait_idle(cqspi);
+       } else {
                ret = cqspi_indirect_write_execute(nor, to, buf, len);
+       }
        if (ret)
                return ret;