4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Lowe <andy_lowe@xxxxxxxxxx>
[ Upstream commit 7464779fa8551b90d5797d4020b0bdb7e6422eb9 ]
If a port has no dma channel defined in the device tree, then
don't attempt to allocate a dma channel for the port.
Also suppress the warning message concerning the failure to allocate
a dma channel. Continue to emit the warning message if a dma
channel is defined but cannot be allocated.
Signed-off-by: Andy Lowe <andy_lowe@xxxxxxxxxx>
Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/sh-sci.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1491,6 +1491,14 @@ static void sci_request_dma(struct uart_
return;
s->cookie_tx = -EINVAL;
+
+ /*
+ * Don't request a dma channel if no channel was specified
+ * in the device tree.
+ */
+ if (!of_find_property(port->dev->of_node, "dmas", NULL))
+ return;
+
chan = sci_request_dma_chan(port, DMA_MEM_TO_DEV);
dev_dbg(port->dev, "%s: TX: got channel %p\n", __func__, chan);
if (chan) {