From patchwork Tue Jun 7 18:52:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vijaya Krishna Nivarthi X-Patchwork-Id: 579764 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 775EDC433EF for ; Tue, 7 Jun 2022 21:11:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379263AbiFGVLy (ORCPT ); Tue, 7 Jun 2022 17:11:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380094AbiFGVL3 (ORCPT ); Tue, 7 Jun 2022 17:11:29 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBC2A217639; Tue, 7 Jun 2022 11:53:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1654627989; x=1686163989; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=DJX1fTXVl6qyeFmIlJ6koAYNPAMtDi8XGkKfp/5Rjkk=; b=OCHIyRs9DtIpE3t6KEdc/Sn6Pj4wgi7d8G0+H6n7SRoJZGft383hbNly IbUtL7MU99R8ipjARhLUzWttPDQHhgcp2Ajzkf6j1+HfY/AMdSn86wL19 ubHqOKvF8IMThdDk4PuNAy4tAC3iFaRF54DBB7df+BDWHJKxCmon5U4LS g=; Received: from ironmsg09-lv.qualcomm.com ([10.47.202.153]) by alexa-out.qualcomm.com with ESMTP; 07 Jun 2022 11:53:07 -0700 X-QCInternal: smtphost Received: from ironmsg01-blr.qualcomm.com ([10.86.208.130]) by ironmsg09-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 07 Jun 2022 11:53:06 -0700 X-QCInternal: smtphost Received: from hu-vnivarth-hyd.qualcomm.com (HELO hu-sgudaval-hyd.qualcomm.com) ([10.213.111.166]) by ironmsg01-blr.qualcomm.com with ESMTP; 08 Jun 2022 00:22:52 +0530 Received: by hu-sgudaval-hyd.qualcomm.com (Postfix, from userid 3994820) id 898523F76; Wed, 8 Jun 2022 00:22:51 +0530 (+0530) From: Vijaya Krishna Nivarthi To: agross@kernel.org, bjorn.andersson@linaro.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Cc: quic_msavaliy@quicinc.com, dianders@chromium.org, mka@chromium.org, swboyd@chromium.org, Vijaya Krishna Nivarthi Subject: [PATCH 1/2] serial: core: Introduce callback for start_rx and do stop_rx in suspend only if this callback implementation is present. Date: Wed, 8 Jun 2022 00:22:44 +0530 Message-Id: <1654627965-1461-2-git-send-email-quic_vnivarth@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1654627965-1461-1-git-send-email-quic_vnivarth@quicinc.com> References: <1654627965-1461-1-git-send-email-quic_vnivarth@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org In suspend sequence there is a need to perform stop_rx during suspend sequence to prevent any asynchronous data over rx line. However this can cause problem to drivers which dont do re-start_rx during set_termios. Add new callback start_rx and perform stop_rx only when implementation of start_rx is present. Also add call to start_rx in resume sequence so that drivers who come across this problem can make use of this framework. Fixes: c9d2325cdb92 ("serial: core: Do stop_rx in suspend path for console if console_suspend is disabled") Signed-off-by: Vijaya Krishna Nivarthi Reviewed-by: Douglas Anderson --- drivers/tty/serial/serial_core.c | 9 ++++++--- include/linux/serial_core.h | 1 + 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 9a85b41..338ebad 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2214,11 +2214,12 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) /* * Nothing to do if the console is not suspending * except stop_rx to prevent any asynchronous data - * over RX line. Re-start_rx, when required, is - * done by set_termios in resume sequence + * over RX line. However ensure that we will be + * able to Re-start_rx later. */ if (!console_suspend_enabled && uart_console(uport)) { - uport->ops->stop_rx(uport); + if (uport->ops->start_rx) + uport->ops->stop_rx(uport); goto unlock; } @@ -2310,6 +2311,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) if (console_suspend_enabled) uart_change_pm(state, UART_PM_STATE_ON); uport->ops->set_termios(uport, &termios, NULL); + if (!console_suspend_enabled && uport->ops->start_rx) + uport->ops->start_rx(uport); if (console_suspend_enabled) console_start(uport->cons); } diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index cbd5070..657a0fc 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -45,6 +45,7 @@ struct uart_ops { void (*unthrottle)(struct uart_port *); void (*send_xchar)(struct uart_port *, char ch); void (*stop_rx)(struct uart_port *); + void (*start_rx)(struct uart_port *); void (*enable_ms)(struct uart_port *); void (*break_ctl)(struct uart_port *, int ctl); int (*startup)(struct uart_port *);