Stop dmaengine transfer in sci_stop_tx(). Otherwise, the following
message is possible output when system enters suspend and while
transferring data, because clearing TIE bit in SCSCR is not able to
stop any dmaengine transfer.
sh-sci e6550000.serial: ttySC1: Unable to drain transmitter
Notes:
- sci_dma_stop_tx() is a macro in the .h file because struct sci_port
is declared in the .c file and #ifdef should be in the .h file.
- This patch uses dmaengine_terminate_async() so that we can apply
this into longterm kernel v4.9.x or later.
Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
Changes from v1:
- Don't put #ifdef in the .c file.
- Update the commit description.
https://lore.kernel.org/linux-renesas-soc/TY2PR01MB3692C545672195370487FA60D83C9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#t
drivers/tty/serial/sh-sci.c | 2 ++
drivers/tty/serial/sh-sci.h | 16 ++++++++++++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 4baf1316ea72..3793cf9f352c 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -610,6 +610,8 @@ static void sci_stop_tx(struct uart_port *port)
ctrl &= ~SCSCR_TIE;
serial_port_out(port, SCSCR, ctrl);
+
+ sci_dma_stop_tx(port);
}
static void sci_start_rx(struct uart_port *port)
diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index c0dfe4382898..435c674af1ce 100644
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -174,3 +174,19 @@ enum {
(((port)->type == PORT_SCI) ? SCI_TDxE_CLEAR : SCIF_TDxE_CLEAR)
#define SCxSR_BREAK_CLEAR(port) \
(((port)->type == PORT_SCI) ? SCI_BREAK_CLEAR : SCIF_BREAK_CLEAR)
+
+#ifdef CONFIG_SERIAL_SH_SCI_DMA
+#define sci_dma_stop_tx(port) \
+{ \
+ struct sci_port *s = to_sci_port(port); \
+ \
+ if (s->chan_tx && !dma_submit_error(s->cookie_tx)) { \
+ dmaengine_terminate_async(s->chan_tx); \
+ s->cookie_tx = -EINVAL; \
+ } \
+}
+#else
+static inline void sci_dma_stop_tx(struct uart_port *port)
+{
+}
+#endif /* CONFIG_SERIAL_SH_SCI_DMA */
--
2.25.1
