From patchwork Mon Jan 25 13:48:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 371120 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72036C433E9 for ; Tue, 26 Jan 2021 05:42:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FE6A2223D for ; Tue, 26 Jan 2021 05:42:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388348AbhAZFmg (ORCPT ); Tue, 26 Jan 2021 00:42:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:49190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729101AbhAYNvC (ORCPT ); Mon, 25 Jan 2021 08:51:02 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id EA2E622B3B; Mon, 25 Jan 2021 13:48:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611582505; bh=rzy6JQ7F/EugWU8tK/NmPdX8jnCIpy4RnsHcMdpnLIo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZuwUtmCe5KLJq5zCG5W2uoP06HZd3dSkSAU2WWCU2R19zcsR3JDZos4Rr42ELlxfY y/0M9RVkVyOftQLxiJhCs0l5WLd3aHqDXQ5/Xt2wr22rPJ1m8RAlXroiNoTl33Vx2o /XFr26yC4sLG9wSxlDdG8i/g8kNUa09jnqCEn1IjFCT9949uw4plNLsFGdu2T1vHDm UI3XDEuka0nOn6T+Yx7OdxM/cSlapf7T7pOpBMgY1dFgTL3/GhBHfZzLcvkh3upzCK BqJu5fgm/2sumL+SGUZonH2gL7J5o0/k/9eFYuZlVDO/OYJBrZcGIGSEzA2/BeMIHJ HLb0CVr1tAxLQ== Received: from johan by xi.lan with local (Exim 4.93.0.4) (envelope-from ) id 1l42EL-00034O-IT; Mon, 25 Jan 2021 14:48:33 +0100 From: Johan Hovold To: linux-usb@vger.kernel.org Cc: Pho Tran , linux-kernel@vger.kernel.org, Johan Hovold , Pho Tran Subject: [PATCH 1/7] USB: serial: cp210x: suppress modem-control errors Date: Mon, 25 Jan 2021 14:48:11 +0100 Message-Id: <20210125134817.11749-2-johan@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210125134817.11749-1-johan@kernel.org> References: <20210125134817.11749-1-johan@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The CP210X_SET_MHS request cannot be used to control RTS when hardware flow control (auto-RTS) is enabled and instead returns an error which is currently logged as: cp210x ttyUSB0: failed set request 0x7 status: -32 when opening and closing a port (and on TIOCMSET requests). Add a crtscts flag to keep track of the hardware flow-control setting and use it to suppress any request to change RTS when auto-RTS is enabled. Note that RTS is still deasserted when disabling the UART as part of close. Reported-by: Pho Tran Signed-off-by: Johan Hovold --- drivers/usb/serial/cp210x.c | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index d813a052738f..7e4a09b42c99 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -21,6 +21,7 @@ #include #include #include +#include #define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver" @@ -264,7 +265,10 @@ struct cp210x_port_private { u8 bInterfaceNumber; bool event_mode; enum cp210x_event_state event_state; - u8 lsr; + u8 lsr; + + struct mutex mutex; + bool crtscts; }; static struct usb_serial_driver cp210x_device = { @@ -1117,6 +1121,7 @@ static bool cp210x_termios_change(const struct ktermios *a, const struct ktermio static void cp210x_set_flow_control(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios) { + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); struct cp210x_special_chars chars; struct cp210x_flow_ctl flow_ctl; u32 flow_repl; @@ -1143,10 +1148,12 @@ static void cp210x_set_flow_control(struct tty_struct *tty, return; } + mutex_lock(&port_priv->mutex); + ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl, sizeof(flow_ctl)); if (ret) - return; + goto out_unlock; ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake); flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace); @@ -1161,10 +1168,12 @@ static void cp210x_set_flow_control(struct tty_struct *tty, ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE; flow_repl &= ~CP210X_SERIAL_RTS_MASK; flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_FLOW_CTL); + port_priv->crtscts = true; } else { ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE; flow_repl &= ~CP210X_SERIAL_RTS_MASK; flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE); + port_priv->crtscts = false; } if (I_IXOFF(tty)) @@ -1188,6 +1197,8 @@ static void cp210x_set_flow_control(struct tty_struct *tty, cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl, sizeof(flow_ctl)); +out_unlock: + mutex_unlock(&port_priv->mutex); } static void cp210x_set_termios(struct tty_struct *tty, @@ -1272,7 +1283,9 @@ static int cp210x_tiocmset(struct tty_struct *tty, static int cp210x_tiocmset_port(struct usb_serial_port *port, unsigned int set, unsigned int clear) { + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); u16 control = 0; + int ret; if (set & TIOCM_RTS) { control |= CONTROL_RTS; @@ -1291,9 +1304,22 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port, control |= CONTROL_WRITE_DTR; } + mutex_lock(&port_priv->mutex); + + /* + * SET_MHS cannot be used to control RTS when auto-RTS is enabled. + * Note that RTS is still deasserted when disabling the UART on close. + */ + if (port_priv->crtscts) + control &= ~CONTROL_WRITE_RTS; + dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control); - return cp210x_write_u16_reg(port, CP210X_SET_MHS, control); + ret = cp210x_write_u16_reg(port, CP210X_SET_MHS, control); + + mutex_unlock(&port_priv->mutex); + + return ret; } static void cp210x_dtr_rts(struct usb_serial_port *port, int on) @@ -1770,6 +1796,7 @@ static int cp210x_port_probe(struct usb_serial_port *port) return -ENOMEM; port_priv->bInterfaceNumber = cp210x_interface_num(serial); + mutex_init(&port_priv->mutex); usb_set_serial_port_data(port, port_priv);