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[v4] serial: sh-sci: Stop dmaengine transfer in sci_stop_tx()

Message ID 20210610110806.277932-1-yoshihiro.shimoda.uh@renesas.com (mailing list archive)
State New
Delegated to: Geert Uytterhoeven
Headers show
Series [v4] serial: sh-sci: Stop dmaengine transfer in sci_stop_tx() | expand

Commit Message

Yoshihiro Shimoda June 10, 2021, 11:08 a.m. UTC
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

Note that this driver has already used some #ifdef in the .c file
so that this patch also uses #ifdef to fix the issue. Otherwise,
build errors happens if the CONFIG_SERIAL_SH_SCI_DMA is disabled.

Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.")
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
 Changes from v3:
 - Add a description why the patch need #ifdef.
 - Add Cc: stable ML tag.

 Changes from v2:
 - Don't use a macro.
 - Revise the commit descrption.

 Changes from v1:
 - Don't put #ifdef in the .c file.
 - Update the commit description.

 drivers/tty/serial/sh-sci.c | 8 ++++++++
 1 file changed, 8 insertions(+)
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diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 4baf1316ea72..2d5487bf6855 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -610,6 +610,14 @@  static void sci_stop_tx(struct uart_port *port)
 	ctrl &= ~SCSCR_TIE;
 	serial_port_out(port, SCSCR, ctrl);
+	if (to_sci_port(port)->chan_tx &&
+	    !dma_submit_error(to_sci_port(port)->cookie_tx)) {
+		dmaengine_terminate_async(to_sci_port(port)->chan_tx);
+		to_sci_port(port)->cookie_tx = -EINVAL;
+	}
 static void sci_start_rx(struct uart_port *port)