From patchwork Thu Oct 15 06:47:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sheng Long Wang X-Patchwork-Id: 269847 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 5A8DBC433DF for ; Thu, 15 Oct 2020 07:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5E312224E for ; Thu, 15 Oct 2020 07:04:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="KKACyZCS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726636AbgJOHEi (ORCPT ); Thu, 15 Oct 2020 03:04:38 -0400 Received: from m12-18.163.com ([220.181.12.18]:39827 "EHLO m12-18.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725208AbgJOHEi (ORCPT ); Thu, 15 Oct 2020 03:04:38 -0400 X-Greylist: delayed 911 seconds by postgrey-1.27 at vger.kernel.org; Thu, 15 Oct 2020 03:04:20 EDT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=eekp+vePaR58kKs2/D zKasR7RTLEDIkhqKj4rE3F0/Q=; b=KKACyZCSQw6jMz8iMA7YQocfsahlqRKsVj s0Ej6SB1lX2501M3Tip8tbZNmdvQiS779mvxyYdSSNxkw+q2J0mCgOJH3ZbF9xab BSbGBviokwLJVH3EbKWqaY7AC2OjKWA7bsFLklgRFdD9U/j0O/wTc6G01w30KbmA 54VfRLLTw= Received: from localhost.localdomain (unknown [118.113.10.145]) by smtp14 (Coremail) with SMTP id EsCowAAnL6OB8IdffjV4TQ--.823S4; Thu, 15 Oct 2020 14:47:30 +0800 (CST) From: Sheng Long Wang To: johan@kernel.org, gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Wang Sheng Long Subject: [PATCH v5] usb-serial:cp210x: add support to software flow control Date: Thu, 15 Oct 2020 14:47:10 +0800 Message-Id: <20201015064710.19786-1-china_shenglong@163.com> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: EsCowAAnL6OB8IdffjV4TQ--.823S4 X-Coremail-Antispam: 1Uf129KBjvJXoW3JF45Jw18Jr45GF1rXr48Crg_yoWxWr4UpF 1rKrWFyFWDZa1YgF4FyF4Uur98ua1SqFyqyFyak39IyF43G3yfKF1xGa4Yyw1UAr48Jry5 JrnIyFyDuF4DArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jDSdDUUUUU= X-Originating-IP: [118.113.10.145] X-CM-SenderInfo: xfkl0tpbvkv0xjor0wi6rwjhhfrp/1tbiXwK+sl15zLxgCwAAsu Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Wang Sheng Long When data is transmitted between two serial ports, the phenomenon of data loss often occurs. The two kinds of flow control commonly used in serial communication are hardware flow control and software flow control. In serial communication, If you only use RX/TX/GND Pins, you can't do hardware flow. So we often used software flow control and prevent data loss. The user sets the software flow control through the application program, and the application program sets the software flow control mode for the serial port chip through the driver. For the cp210 serial port chip, its driver lacks the software flow control setting code, so the user cannot set the software flow control function through the application program. This adds the missing software flow control. Signed-off-by: Wang Sheng Long Changes in v3: - fixed code style, It mainly adjusts the code style acccording to kernel specification. Changes in v4: - It mainly adjusts the patch based on the last usb-next branch of the usb-serial. Changes in v5: - Fixes: * According to the cp210x specification, use usb_control_msg() requesttype 'REQTYPE_DEVICE_TO_HOST' is modified to 'REQTYPE_INTERFACE_TO_HOST' in cp210x_get_chars(). * If modify IXOFF/IXON has been changed, we can call set software flow control code. * If the setting software flow control wrong, do not continue processing proceed with updating software flow control. Reported-by: kernel test robot --- drivers/usb/serial/cp210x.c | 128 ++++++++++++++++++++++++++++++++++-- 1 file changed, 123 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index d0c05aa8a0d6..d2edf9e4d484 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -412,6 +412,15 @@ struct cp210x_comm_status { u8 bReserved; } __packed; +struct cp210x_special_chars { + u8 bEofChar; + u8 bErrorChar; + u8 bBreakChar; + u8 bEventChar; + u8 bXonChar; + u8 bXoffChar; +}; + /* * CP210X_PURGE - 16 bits passed in wValue of USB request. * SiLabs app note AN571 gives a strange description of the 4 bits: @@ -675,6 +684,70 @@ static int cp210x_read_vendor_block(struct usb_serial *serial, u8 type, u16 val, return result; } +static int cp210x_get_chars(struct usb_serial_port *port, void *buf) +{ + struct usb_serial *serial = port->serial; + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); + struct cp210x_special_chars *special_chars; + void *dmabuf; + int result; + + dmabuf = kmemdup(buf, sizeof(*special_chars), GFP_KERNEL); + if (!dmabuf) + return -ENOMEM; + + result = usb_control_msg(serial->dev, + usb_rcvctrlpipe(serial->dev, 0), + CP210X_GET_CHARS, REQTYPE_INTERFACE_TO_HOST, 0, + port_priv->bInterfaceNumber, + dmabuf, sizeof(*special_chars), + USB_CTRL_GET_TIMEOUT); + + if (result == sizeof(*special_chars)) { + memcpy(buf, dmabuf, sizeof(*special_chars)); + result = 0; + } else { + dev_err(&port->dev, "failed to get special chars: %d\n", result); + if (result >= 0) + result = -EIO; + } + + kfree(dmabuf); + + return result; +} + +static int cp210x_set_chars(struct usb_serial_port *port, void *buf) +{ + struct usb_serial *serial = port->serial; + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port); + struct cp210x_special_chars *special_chars; + void *dmabuf; + int result; + + dmabuf = kmemdup(buf, sizeof(*special_chars), GFP_KERNEL); + if (!dmabuf) + return -ENOMEM; + + result = usb_control_msg(serial->dev, + usb_sndctrlpipe(serial->dev, 0), + CP210X_SET_CHARS, REQTYPE_HOST_TO_INTERFACE, 0, + port_priv->bInterfaceNumber, + dmabuf, sizeof(*special_chars), USB_CTRL_SET_TIMEOUT); + + if (result == sizeof(*special_chars)) { + result = 0; + } else { + dev_err(&port->dev, "failed to set special chars: %d\n", result); + if (result >= 0) + result = -EIO; + } + + kfree(dmabuf); + + return result; +} + /* * Writes any 16-bit CP210X_ register (req) whose value is passed * entirely in the wValue field of the USB request. @@ -1356,11 +1429,18 @@ static void cp210x_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios) { struct device *dev = &port->dev; - unsigned int cflag, old_cflag; + unsigned int cflag, old_cflag, iflag, old_iflag; + struct cp210x_special_chars special_chars; + struct cp210x_flow_ctl flow_ctl; u16 bits; + int result; + u32 ctl_hs; + u32 flow_repl; cflag = tty->termios.c_cflag; + iflag = tty->termios.c_iflag; old_cflag = old_termios->c_cflag; + old_iflag = old_termios->c_iflag; if (tty->termios.c_ospeed != old_termios->c_ospeed) cp210x_change_speed(tty, port, old_termios); @@ -1434,10 +1514,6 @@ static void cp210x_set_termios(struct tty_struct *tty, } if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) { - struct cp210x_flow_ctl flow_ctl; - u32 ctl_hs; - u32 flow_repl; - cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl, sizeof(flow_ctl)); ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake); @@ -1474,6 +1550,48 @@ static void cp210x_set_termios(struct tty_struct *tty, sizeof(flow_ctl)); } + if (((iflag & IXOFF) != (old_iflag & IXOFF)) || + ((iflag & IXON) != (old_iflag & IXON))) { + result = cp210x_get_chars(port, &special_chars); + if (result < 0) + goto out; + + special_chars.bXonChar = START_CHAR(tty); + special_chars.bXoffChar = STOP_CHAR(tty); + + result = cp210x_set_chars(port, &special_chars); + if (result < 0) + goto out; + + result = cp210x_read_reg_block(port, + CP210X_GET_FLOW, + &flow_ctl, + sizeof(flow_ctl)); + if (result < 0) + goto out; + + flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace); + + if (iflag & IXOFF) + flow_repl |= CP210X_SERIAL_AUTO_RECEIVE; + else + flow_repl &= ~CP210X_SERIAL_AUTO_RECEIVE; + + if (iflag & IXON) + flow_repl |= CP210X_SERIAL_AUTO_TRANSMIT; + else + flow_repl &= ~CP210X_SERIAL_AUTO_TRANSMIT; + + flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl); + result = cp210x_write_reg_block(port, + CP210X_SET_FLOW, + &flow_ctl, + sizeof(flow_ctl)); + } +out: + if (result < 0) + dev_err(dev, "failed to set software flow control: %d\n", result); + /* * Enable event-insertion mode only if input parity checking is * enabled for now.