From patchwork Fri Sep 8 15:36:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Romain Izard X-Patchwork-Id: 9944545 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 817526035D for ; Fri, 8 Sep 2017 15:37:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 71D8B287F2 for ; Fri, 8 Sep 2017 15:37:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6673E287F5; Fri, 8 Sep 2017 15:37:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 00E77287F2 for ; Fri, 8 Sep 2017 15:37:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756518AbdIHPh1 (ORCPT ); Fri, 8 Sep 2017 11:37:27 -0400 Received: from mail-wr0-f196.google.com ([209.85.128.196]:36295 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932413AbdIHPgb (ORCPT ); Fri, 8 Sep 2017 11:36:31 -0400 Received: by mail-wr0-f196.google.com with SMTP id g50so1407715wra.3; Fri, 08 Sep 2017 08:36:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=+UTzhLnF6voZH5hQ1dSzML3l3kABKBZi1KBSzYm72fc=; b=r3hwv39JRwqsiKWhfSuLRkoB2rMQbv2b9qziWnDfCLKSrii1J/3fCEQfcihdgW2WHf Devm9ZXc+0HRzjELE8Y6znBPWcI1NroFWt37/bhkid1wqDx+u/qAwGGR2VNzbTbW3hk5 KUAaflVdpv2YWB059NMMAXrgA007w4p4p0MKduoS41wxY8qPp2g5mCAXapXp3zhgIw8N OvHt0qtz//NfCbeMf7nXDMDC06DvABT0/J7R/Ir1m6J4vzPM5gY9WFwq8aRAU10puwRc J1IR+sbEo4IMs64irA7uLeMazqc3Jcwuy5AixDB6Kz5NETdcXsOZ618CIKqnar971OBT qqSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=+UTzhLnF6voZH5hQ1dSzML3l3kABKBZi1KBSzYm72fc=; b=Vvb8lHOImdFqnowTEvUVf057LhTt29bI+brVZOChlLoNFXCFx/PvdL4n+PAIxoEqyj 9HHWOx+X7GKtti8dJOVvEDfzMIODxfUt2dCcz2WNj8Mubnz8i2zaiuRDhUY7Bh/Lnn1I hOCJrPfLqk3auGVl5r9MRyqFNxpOiFPbYAn00HAuAUA+Om7VQTVehpZycnDIDX1viIPI GJQ2N2Y8ev6QHgxXoA970J4IUuOIq+/O9ZQbliO6w+WSs5/IH7BOI65eV0L4S8bsOk6d 902y58X32bJjEGtbWPxlHX2vdXm9I9qwzpjBrzZja1Tax5H0ypf+VuFAV0HGM66xasrI Ss4A== X-Gm-Message-State: AHPjjUiEdtletgOb7FiURE6D5Q3RW8a0YCVQFAnt1KNTd2ZNZWV5xXRE uH8AVpITIT4QLQ== X-Google-Smtp-Source: ADKCNb7vwAe4LrS7UxyBxEzoK515bJ07MMTL1qcuKyc7SPEoRv4I4NnY9JyXS29BgBwJToPM0PFUNQ== X-Received: by 10.223.145.163 with SMTP id 32mr2377201wri.279.1504884989387; Fri, 08 Sep 2017 08:36:29 -0700 (PDT) Received: from localhost.localdomain (146.187.3.109.rev.sfr.net. [109.3.187.146]) by smtp.gmail.com with ESMTPSA id p199sm1689224wmb.28.2017.09.08.08.36.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Sep 2017 08:36:28 -0700 (PDT) From: Romain Izard To: Nicolas Ferre , Boris Brezillon , Michael Turquette , Stephen Boyd , Ludovic Desroches , Jonathan Cameron , Wenyou Yang , Josh Wu , David Woodhouse , Brian Norris , Marek Vasut , Cyrille Pitchen , Thierry Reding , Richard Genoud , Greg Kroah-Hartman , Alan Stern Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, linux-mtd@lists.infradead.org, linux-pwm@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Romain Izard Subject: [PATCH v1 10/10] tty/serial: atmel: Prevent a warning on suspend Date: Fri, 8 Sep 2017 17:36:04 +0200 Message-Id: <20170908153604.28383-11-romain.izard.pro@gmail.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170908153604.28383-1-romain.izard.pro@gmail.com> References: <20170908153604.28383-1-romain.izard.pro@gmail.com> Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The atmel serial port driver reported the following warning on suspend: atmel_usart f8020000.serial: ttyS1: Unable to drain transmitter As the ATMEL_US_TXEMPTY status bit in ATMEL_US_CSR is always cleared when the transmitter is disabled, we need to know the transmitter's state to return the real fifo state. And as ATMEL_US_CR is write-only, it is necessary to save the state of the transmitter in a local variable, and update the variable when TXEN and TXDIS is written in ATMEL_US_CR. After those changes, atmel_tx_empty can return "empty" on suspend, the warning in uart_suspend_port disappears, and suspending is 20ms shorter for each enabled Atmel serial port. Signed-off-by: Romain Izard --- drivers/tty/serial/atmel_serial.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 7551cab438ff..195c0d1b594e 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -171,6 +171,7 @@ struct atmel_uart_port { bool has_hw_timer; struct timer_list uart_timer; + bool tx_stopped; bool suspended; unsigned int pending; unsigned int pending_status; @@ -380,6 +381,10 @@ static int atmel_config_rs485(struct uart_port *port, */ static u_int atmel_tx_empty(struct uart_port *port) { + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + + if (atmel_port->tx_stopped) + return TIOCSER_TEMT; return (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXEMPTY) ? TIOCSER_TEMT : 0; @@ -485,6 +490,7 @@ static void atmel_stop_tx(struct uart_port *port) * is fully transmitted. */ atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS); + atmel_port->tx_stopped = true; /* Disable interrupts */ atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask); @@ -492,6 +498,7 @@ static void atmel_stop_tx(struct uart_port *port) if ((port->rs485.flags & SER_RS485_ENABLED) && !(port->rs485.flags & SER_RS485_RX_DURING_TX)) atmel_start_rx(port); + } /* @@ -521,6 +528,7 @@ static void atmel_start_tx(struct uart_port *port) /* re-enable the transmitter */ atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN); + atmel_port->tx_stopped = false; } /* @@ -1866,6 +1874,7 @@ static int atmel_startup(struct uart_port *port) atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); /* enable xmit & rcvr */ atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); + atmel_port->tx_stopped = false; setup_timer(&atmel_port->uart_timer, atmel_uart_timer_callback, @@ -2122,6 +2131,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, /* disable receiver and transmitter */ atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXDIS); + atmel_port->tx_stopped = true; /* mode */ if (port->rs485.flags & SER_RS485_ENABLED) { @@ -2207,6 +2217,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, atmel_uart_writel(port, ATMEL_US_BRGR, quot); atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); + atmel_port->tx_stopped = false; /* restore interrupts */ atmel_uart_writel(port, ATMEL_US_IER, imr); @@ -2450,6 +2461,7 @@ static void atmel_console_write(struct console *co, const char *s, u_int count) /* Make sure that tx path is actually able to send characters */ atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN); + atmel_port->tx_stopped = false; uart_console_write(port, s, count, atmel_console_putchar); @@ -2528,6 +2540,7 @@ static int __init atmel_console_setup(struct console *co, char *options) atmel_uart_writel(port, ATMEL_US_IDR, -1); atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX); atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN); + atmel_port->tx_stopped = false; if (options) uart_parse_options(options, &baud, &parity, &bits, &flow);