[PATCH 3/4] serial: 8250_lpss: Use 16B DMA burst with Elkhart Lake

[Ilpo Järvinen]

Configure DMA to use 16B burst size with Elkhart Lake. This makes the
bus use more efficient and works around an issue which occurs with the
previously used 1B.

Fixes: 0a9410b981e9 ("serial: 8250_lpss: Enable DMA on Intel Elkhart Lake")
Cc: <stable@xxxxxxxxxxxxxxx> # serial: 8250_lpss: Configure DMA also w/o DMA filter
Reported-by: Wentong Wu <wentong.wu@xxxxxxxxx>
Co-developed-by: Srikanth Thokala <srikanth.thokala@xxxxxxxxx>
Signed-off-by: Srikanth Thokala <srikanth.thokala@xxxxxxxxx>
Co-developed-by: Aman Kumar <aman.kumar@xxxxxxxxx>
Signed-off-by: Aman Kumar <aman.kumar@xxxxxxxxx>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>

---
I know the list of Co-dev-bys & Sob seems a bit odd for a oneliner.
The reason is that I cleaned up this from a more complex patch using
the earlier change that I authored myself so only this oneliner
remained in this patch.
---
 drivers/tty/serial/8250/8250_lpss.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index ed281445a97d..e0b4e1446eac 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -174,6 +174,8 @@ static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 	 */
 	up->dma = dma;
 
+	lpss->dma_maxburst = 16;
+
 	port->set_termios = dw8250_do_set_termios;
 
 	return 0;
-- 
2.30.2