Commit 1707ce2d authored by Biju Das's avatar Biju Das Committed by Greg Kroah-Hartman
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tty: serial: sh-sci: Fix TE setting on SCI IP 



As per the RZ/G2L users hardware manual (Rev.1.20 Sep, 2022), section
23.3.7 Serial Data Transmission (Asynchronous Mode) it is mentioned
that the TE (transmit enable) must be set after setting TIE (transmit
interrupt enable) or these 2 bits are set to 1 simultaneously by a
single instruction. So set these 2 bits in single instruction.

Signed-off-by: default avatarBiju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20230412145053.114847-4-biju.das.jz@bp.renesas.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cf383d12

drivers/tty/serial/sh-sci.c

+17 −2
Original line number Diff line number Diff line
@@ -601,6 +601,15 @@ static void sci_start_tx(struct uart_port *port) 
	    port->type == PORT_SCIFA || port->type == PORT_SCIFB) {

		/* Set TIE (Transmit Interrupt Enable) bit in SCSCR */

		ctrl = serial_port_in(port, SCSCR);



		/*

		 * For SCI, TE (transmit enable) must be set after setting TIE

		 * (transmit interrupt enable) or in the same instruction to start

		 * the transmit process.

		 */

		if (port->type == PORT_SCI)

			ctrl |= SCSCR_TE;



		serial_port_out(port, SCSCR, ctrl | SCSCR_TIE);

	}

}
@@ -2600,8 +2609,14 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, 
		sci_set_mctrl(port, port->mctrl);

	}



	scr_val |= SCSCR_RE | SCSCR_TE |

		   (s->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0));

	/*

	 * For SCI, TE (transmit enable) must be set after setting TIE

	 * (transmit interrupt enable) or in the same instruction to

	 * start the transmitting process. So skip setting TE here for SCI.

	 */

	if (port->type != PORT_SCI)

		scr_val |= SCSCR_TE;

	scr_val |= SCSCR_RE | (s->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0));

	serial_port_out(port, SCSCR, scr_val | s->hscif_tot);

	if ((srr + 1 == 5) &&

	    (port->type == PORT_SCIFA || port->type == PORT_SCIFB)) {