patch "serial: sh-sci: Fix setting SCSCR_TIE while transferring data" added to tty-linus

This is a note to let you know that I've just added the patch titled

serial: sh-sci: Fix setting SCSCR_TIE while transferring data

to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 93bcefd4c6bad4c69dbc4edcd3fbf774b24d930d Mon Sep 17 00:00:00 2001
From: Hoan Nguyen An <[email protected]>
Date: Mon, 18 Mar 2019 18:26:32 +0900
Subject: serial: sh-sci: Fix setting SCSCR_TIE while transferring data

We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted (if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer, re-enable the SCSCR_TIE bit, which was done at sci_start_tx().
This is unnecessary processing, wasting CPU operation if the data transmission length is large. And further, transmit end, FIFO empty bits disabling have also been performed in the step above.

---
 drivers/tty/serial/sh-sci.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

index 060fcd42b6d5..2d1c626312cd 100644
@@ -838,19 +838,9 @@ static void sci_transmit_chars(struct uart_port *port)
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
-	if (uart_circ_empty(xmit)) {
+	if (uart_circ_empty(xmit))
 		sci_stop_tx(port);
-	} else {
-		ctrl = serial_port_in(port, SCSCR);
-
-		if (port->type != PORT_SCI) {
-			serial_port_in(port, SCxSR); /* Dummy read */
-			sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
-		}
 
-		ctrl |= SCSCR_TIE;
-		serial_port_out(port, SCSCR, ctrl);
-	}
 }
 
 /* On SH3, SCIF may read end-of-break as a space->mark char */

2.21.0