From patchwork Mon Mar 20 10:53:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Biju Das X-Patchwork-Id: 665497 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CD28C7618D for ; Mon, 20 Mar 2023 10:59:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231127AbjCTK7d (ORCPT ); Mon, 20 Mar 2023 06:59:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230002AbjCTK6i (ORCPT ); Mon, 20 Mar 2023 06:58:38 -0400 Received: from relmlie5.idc.renesas.com (relmlor1.renesas.com [210.160.252.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id AD4B22916A; Mon, 20 Mar 2023 03:55:07 -0700 (PDT) X-IronPort-AV: E=Sophos;i="5.98,274,1673881200"; d="scan'208";a="153188045" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie5.idc.renesas.com with ESMTP; 20 Mar 2023 19:53:55 +0900 Received: from localhost.localdomain (unknown [10.226.92.205]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id CE9474004BCF; Mon, 20 Mar 2023 19:53:52 +0900 (JST) From: Biju Das To: Greg Kroah-Hartman Cc: Biju Das , Jiri Slaby , Geert Uytterhoeven , Yoshinori Sato , linux-serial@vger.kernel.org, Prabhakar Mahadev Lad , linux-renesas-soc@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v3 3/5] tty: serial: sh-sci: Fix Tx on SCI IP Date: Mon, 20 Mar 2023 10:53:37 +0000 Message-Id: <20230320105339.236279-4-biju.das.jz@bp.renesas.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230320105339.236279-1-biju.das.jz@bp.renesas.com> References: <20230320105339.236279-1-biju.das.jz@bp.renesas.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org For SCI, the TE (transmit enable) must be set after setting TIE (transmit interrupt enable) or in the same instruction to start the transmission. Set TE bit in sci_start_tx() instead of set_termios() for SCI and clear TE bit, if circular buffer is empty in sci_transmit_chars(). Fixes: f9a2adcc9e90 ("arm64: dts: renesas: r9a07g044: Add SCI[0-1] nodes") Cc: stable@vger.kernel.org Signed-off-by: Biju Das --- v3: * New patch --- drivers/tty/serial/sh-sci.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index b9cd27451f90..9079a8ea9132 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -597,6 +597,15 @@ static void sci_start_tx(struct uart_port *port) if (!s->chan_tx || 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); } } @@ -835,6 +844,12 @@ static void sci_transmit_chars(struct uart_port *port) c = xmit->buf[xmit->tail]; xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); } else { + if (port->type == PORT_SCI) { + ctrl = serial_port_in(port, SCSCR); + ctrl &= ~SCSCR_TE; + serial_port_out(port, SCSCR, ctrl); + return; + } break; } @@ -2581,8 +2596,14 @@ 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)) {