From: Andy Lowe andy_lowe@mentor.com
[ 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@mentor.com Signed-off-by: Eugeniu Rosca erosca@de.adit-jv.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com --- drivers/tty/serial/sh-sci.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 784dd42002ea..761b9f5f1491 100644 --- 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_port *port) 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) {