USB: serial: add Moxa UPORT 12XX/14XX/16XX driver

Add a driver which supports the following Moxa USB to serial converters:
*       2 ports : UPort 1250, UPort 1250I
*       4 ports : UPort 1410, UPort 1450, UPort 1450I
*       8 ports : UPort 1610-8, UPort 1650-8
*      16 ports : UPort 1610-16, UPort 1650-16

The UPORT devices don't directly fit the USB serial model. USB serial
assumes a bulk in/out endpoint pair per serial port. Thus a dual port
USB serial device is expected to have two bulk in/out pairs. The Moxa
UPORT only has one pair for data transfer and places a header on each
transfer over the endpoint indicating for which port the transfer
relates to. There is a second endpoint pair for events, such as modem
control lines changing state, setting baud rates etc. Again, a
multiplexing header is used on these endpoints.

Some ports need to have a kfifo explicitly allocated since the
framework does not allocate one if there is no associated endpoints.
The framework will however free it on unload of the module.

All data transfers are made on port0, yet the locks are taken on PortN.
urb->context points to PortN, even though the URB is for port0.

Where possible, code from the generic driver is called. However
mxuport_process_read_urb_data() is mostly a cut/paste of
usb_serial_generic_process_read_urb().

The driver will attempt to load firmware from userspace and compare
the available version and the running version. If the available
version is newer, it will be download into RAM of the device and
started. This is optional and the driver appears to work O.K. with
older firmware in the devices ROM.

This driver is based on the MOXA driver and retains MOXAs copyright.

[jhovold@gmail.com: fix get_fw_version error path and some style issues]
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/Kconfig

@@ -472,6 +472,35 @@ config USB_SERIAL_MOS7840
 	  To compile this driver as a module, choose M here: the
 	  module will be called mos7840.  If unsure, choose N.
 
+config USB_SERIAL_MXUPORT
+	tristate "USB Moxa UPORT Serial Driver"
+	---help---
+	  Say Y here if you want to use a MOXA UPort Serial hub.
+
+	  This driver supports:
+
+	  [2 Port]
+	  - UPort 1250 :  2 Port RS-232/422/485 USB to Serial Hub
+	  - UPort 1250I : 2 Port RS-232/422/485 USB to Serial Hub with
+			  Isolation
+
+	  [4 Port]
+	  - UPort 1410 :  4 Port RS-232 USB to Serial Hub
+	  - UPort 1450 :  4 Port RS-232/422/485 USB to Serial Hub
+	  - UPort 1450I : 4 Port RS-232/422/485 USB to Serial Hub with
+			  Isolation
+
+	  [8 Port]
+	  - UPort 1610-8 : 8 Port RS-232 USB to Serial Hub
+	  - UPort 1650-8 : 8 Port RS-232/422/485 USB to Serial Hub
+
+	  [16 Port]
+	  - UPort 1610-16 : 16 Port RS-232 USB to Serial Hub
+	  - UPort 1650-16 : 16 Port RS-232/422/485 USB to Serial Hub
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mxuport.
+
 config USB_SERIAL_NAVMAN
 	tristate "USB Navman GPS device"
 	help

drivers/usb/serial/Makefile

@@ -37,6 +37,7 @@ obj-$(CONFIG_USB_SERIAL_MCT_U232)		+= mct_u232.o
 obj-$(CONFIG_USB_SERIAL_METRO)			+= metro-usb.o
 obj-$(CONFIG_USB_SERIAL_MOS7720)		+= mos7720.o
 obj-$(CONFIG_USB_SERIAL_MOS7840)		+= mos7840.o
+obj-$(CONFIG_USB_SERIAL_MXUPORT)		+= mxuport.o
 obj-$(CONFIG_USB_SERIAL_NAVMAN)			+= navman.o
 obj-$(CONFIG_USB_SERIAL_OMNINET)		+= omninet.o
 obj-$(CONFIG_USB_SERIAL_OPTICON)		+= opticon.o

drivers/usb/serial/mxuport.c

+/*
+ *	mxuport.c - MOXA UPort series driver
+ *
+ *	Copyright (c) 2006 Moxa Technologies Co., Ltd.
+ *	Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
+ *
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License as published by
+ *	the Free Software Foundation; either version 2 of the License, or
+ *	(at your option) any later version.
+ *
+ *	Supports the following Moxa USB to serial converters:
+ *	 2 ports : UPort 1250, UPort 1250I
+ *	 4 ports : UPort 1410, UPort 1450, UPort 1450I
+ *	 8 ports : UPort 1610-8, UPort 1650-8
+ *	16 ports : UPort 1610-16, UPort 1650-16
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/firmware.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/serial.h>
+#include <linux/serial_reg.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/uaccess.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <asm/unaligned.h>
+
+/* Definitions for the vendor ID and device ID */
+#define MX_USBSERIAL_VID	0x110A
+#define MX_UPORT1250_PID	0x1250
+#define MX_UPORT1251_PID	0x1251
+#define MX_UPORT1410_PID	0x1410
+#define MX_UPORT1450_PID	0x1450
+#define MX_UPORT1451_PID	0x1451
+#define MX_UPORT1618_PID	0x1618
+#define MX_UPORT1658_PID	0x1658
+#define MX_UPORT1613_PID	0x1613
+#define MX_UPORT1653_PID	0x1653
+
+/* Definitions for USB info */
+#define HEADER_SIZE		4
+#define EVENT_LENGTH		8
+#define DOWN_BLOCK_SIZE		64
+
+/* Definitions for firmware info */
+#define VER_ADDR_1		0x20
+#define VER_ADDR_2		0x24
+#define VER_ADDR_3		0x28
+
+/* Definitions for USB vendor request */
+#define RQ_VENDOR_NONE			0x00
+#define RQ_VENDOR_SET_BAUD		0x01 /* Set baud rate */
+#define RQ_VENDOR_SET_LINE		0x02 /* Set line status */
+#define RQ_VENDOR_SET_CHARS		0x03 /* Set Xon/Xoff chars */
+#define RQ_VENDOR_SET_RTS		0x04 /* Set RTS */
+#define RQ_VENDOR_SET_DTR		0x05 /* Set DTR */
+#define RQ_VENDOR_SET_XONXOFF		0x06 /* Set auto Xon/Xoff */
+#define RQ_VENDOR_SET_RX_HOST_EN	0x07 /* Set RX host enable */
+#define RQ_VENDOR_SET_OPEN		0x08 /* Set open/close port */
+#define RQ_VENDOR_PURGE			0x09 /* Purge Rx/Tx buffer */
+#define RQ_VENDOR_SET_MCR		0x0A /* Set MCR register */
+#define RQ_VENDOR_SET_BREAK		0x0B /* Set Break signal */
+
+#define RQ_VENDOR_START_FW_DOWN		0x0C /* Start firmware download */
+#define RQ_VENDOR_STOP_FW_DOWN		0x0D /* Stop firmware download */
+#define RQ_VENDOR_QUERY_FW_READY	0x0E /* Query if new firmware ready */
+
+#define RQ_VENDOR_SET_FIFO_DISABLE	0x0F /* Set fifo disable */
+#define RQ_VENDOR_SET_INTERFACE		0x10 /* Set interface */
+#define RQ_VENDOR_SET_HIGH_PERFOR	0x11 /* Set hi-performance */
+
+#define RQ_VENDOR_ERASE_BLOCK		0x12 /* Erase flash block */
+#define RQ_VENDOR_WRITE_PAGE		0x13 /* Write flash page */
+#define RQ_VENDOR_PREPARE_WRITE		0x14 /* Prepare write flash */
+#define RQ_VENDOR_CONFIRM_WRITE		0x15 /* Confirm write flash */
+#define RQ_VENDOR_LOCATE		0x16 /* Locate the device */
+
+#define RQ_VENDOR_START_ROM_DOWN	0x17 /* Start firmware download */
+#define RQ_VENDOR_ROM_DATA		0x18 /* Rom file data */
+#define RQ_VENDOR_STOP_ROM_DOWN		0x19 /* Stop firmware download */
+#define RQ_VENDOR_FW_DATA		0x20 /* Firmware data */
+
+#define RQ_VENDOR_RESET_DEVICE		0x23 /* Try to reset the device */
+#define RQ_VENDOR_QUERY_FW_CONFIG	0x24
+
+#define RQ_VENDOR_GET_VERSION		0x81 /* Get firmware version */
+#define RQ_VENDOR_GET_PAGE		0x82 /* Read flash page */
+#define RQ_VENDOR_GET_ROM_PROC		0x83 /* Get ROM process state */
+
+#define RQ_VENDOR_GET_INQUEUE		0x84 /* Data in input buffer */
+#define RQ_VENDOR_GET_OUTQUEUE		0x85 /* Data in output buffer */
+
+#define RQ_VENDOR_GET_MSR		0x86 /* Get modem status register */
+
+/* Definitions for UPort event type */
+#define UPORT_EVENT_NONE		0 /* None */
+#define UPORT_EVENT_TXBUF_THRESHOLD	1 /* Tx buffer threshold */
+#define UPORT_EVENT_SEND_NEXT		2 /* Send next */
+#define UPORT_EVENT_MSR			3 /* Modem status */
+#define UPORT_EVENT_LSR			4 /* Line status */
+#define UPORT_EVENT_MCR			5 /* Modem control */
+
+/* Definitions for serial event type */
+#define SERIAL_EV_CTS			0x0008	/* CTS changed state */
+#define SERIAL_EV_DSR			0x0010	/* DSR changed state */
+#define SERIAL_EV_RLSD			0x0020	/* RLSD changed state */
+
+/* Definitions for modem control event type */
+#define SERIAL_EV_XOFF			0x40	/* XOFF received */
+
+/* Definitions for line control of communication */
+#define MX_WORDLENGTH_5			5
+#define MX_WORDLENGTH_6			6
+#define MX_WORDLENGTH_7			7
+#define MX_WORDLENGTH_8			8
+
+#define MX_PARITY_NONE			0
+#define MX_PARITY_ODD			1
+#define MX_PARITY_EVEN			2
+#define MX_PARITY_MARK			3
+#define MX_PARITY_SPACE			4
+
+#define MX_STOP_BITS_1			0
+#define MX_STOP_BITS_1_5		1
+#define MX_STOP_BITS_2			2
+
+#define MX_RTS_DISABLE			0x0
+#define MX_RTS_ENABLE			0x1
+#define MX_RTS_HW			0x2
+#define MX_RTS_NO_CHANGE		0x3 /* Flag, not valid register value*/
+
+#define MX_INT_RS232			0
+#define MX_INT_2W_RS485			1
+#define MX_INT_RS422			2
+#define MX_INT_4W_RS485			3
+
+/* Definitions for holding reason */
+#define MX_WAIT_FOR_CTS			0x0001
+#define MX_WAIT_FOR_DSR			0x0002
+#define MX_WAIT_FOR_DCD			0x0004
+#define MX_WAIT_FOR_XON			0x0008
+#define MX_WAIT_FOR_START_TX		0x0010
+#define MX_WAIT_FOR_UNTHROTTLE		0x0020
+#define MX_WAIT_FOR_LOW_WATER		0x0040
+#define MX_WAIT_FOR_SEND_NEXT		0x0080
+
+#define MX_UPORT_2_PORT			BIT(0)
+#define MX_UPORT_4_PORT			BIT(1)
+#define MX_UPORT_8_PORT			BIT(2)
+#define MX_UPORT_16_PORT		BIT(3)
+
+/* This structure holds all of the local port information */
+struct mxuport_port {
+	u8 mcr_state;		/* Last MCR state */
+	u8 msr_state;		/* Last MSR state */
+	struct mutex mutex;	/* Protects mcr_state */
+	spinlock_t spinlock;	/* Protects msr_state */
+};
+
+/* Table of devices that work with this driver */
+static const struct usb_device_id mxuport_idtable[] = {
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1250_PID),
+	  .driver_info = MX_UPORT_2_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1251_PID),
+	  .driver_info = MX_UPORT_2_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1410_PID),
+	  .driver_info = MX_UPORT_4_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1450_PID),
+	  .driver_info = MX_UPORT_4_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1451_PID),
+	  .driver_info = MX_UPORT_4_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1618_PID),
+	  .driver_info = MX_UPORT_8_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1658_PID),
+	  .driver_info = MX_UPORT_8_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1613_PID),
+	  .driver_info = MX_UPORT_16_PORT },
+	{ USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1653_PID),
+	  .driver_info = MX_UPORT_16_PORT },
+	{}			/* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, mxuport_idtable);
+
+/*
+ * Add a four byte header containing the port number and the number of
+ * bytes of data in the message. Return the number of bytes in the
+ * buffer.
+ */
+static int mxuport_prepare_write_buffer(struct usb_serial_port *port,
+					void *dest, size_t size)
+{
+	u8 *buf = dest;
+	int count;
+
+	count = kfifo_out_locked(&port->write_fifo, buf + HEADER_SIZE,
+				 size - HEADER_SIZE,
+				 &port->lock);
+
+	put_unaligned_be16(port->port_number, buf);
+	put_unaligned_be16(count, buf + 2);
+
+	dev_dbg(&port->dev, "%s - size %zd count %d\n", __func__,
+		size, count);
+
+	return count + HEADER_SIZE;
+}
+
+/* Read the given buffer in from the control pipe. */
+static int mxuport_recv_ctrl_urb(struct usb_serial *serial,
+				 u8 request, u16 value, u16 index,
+				 u8 *data, size_t size)
+{
+	int status;
+
+	status = usb_control_msg(serial->dev,
+				 usb_rcvctrlpipe(serial->dev, 0),
+				 request,
+				 (USB_DIR_IN | USB_TYPE_VENDOR |
+				  USB_RECIP_DEVICE), value, index,
+				 data, size,
+				 USB_CTRL_GET_TIMEOUT);
+	if (status < 0) {
+		dev_err(&serial->interface->dev,
+			"%s - usb_control_msg failed (%d)\n",
+			__func__, status);
+		return status;
+	}
+
+	if (status != size) {
+		dev_err(&serial->interface->dev,
+			"%s - short read (%d / %zd)\n",
+			__func__, status, size);
+		return -EIO;
+	}
+
+	return status;
+}
+
+/* Write the given buffer out to the control pipe.  */
+static int mxuport_send_ctrl_data_urb(struct usb_serial *serial,
+				      u8 request,
+				      u16 value, u16 index,
+				      u8 *data, size_t size)
+{
+	int status;
+
+	status = usb_control_msg(serial->dev,
+				 usb_sndctrlpipe(serial->dev, 0),
+				 request,
+				 (USB_DIR_OUT | USB_TYPE_VENDOR |
+				  USB_RECIP_DEVICE), value, index,
+				 data, size,
+				 USB_CTRL_SET_TIMEOUT);
+	if (status < 0) {
+		dev_err(&serial->interface->dev,
+			"%s - usb_control_msg failed (%d)\n",
+			__func__, status);
+		return status;
+	}
+
+	if (status != size) {
+		dev_err(&serial->interface->dev,
+			"%s - short write (%d / %zd)\n",
+			__func__, status, size);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/* Send a vendor request without any data */
+static int mxuport_send_ctrl_urb(struct usb_serial *serial,
+				 u8 request, u16 value, u16 index)
+{
+	return mxuport_send_ctrl_data_urb(serial, request, value, index,
+					  NULL, 0);
+}
+
+/*
+ * mxuport_throttle - throttle function of driver
+ *
+ * This function is called by the tty driver when it wants to stop the
+ * data being read from the port. Since all the data comes over one
+ * bulk in endpoint, we cannot stop submitting urbs by setting
+ * port->throttle. Instead tell the device to stop sending us data for
+ * the port.
+ */
+static void mxuport_throttle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct usb_serial *serial = port->serial;
+
+	dev_dbg(&port->dev, "%s\n", __func__);
+
+	mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_RX_HOST_EN,
+			      0, port->port_number);
+}
+
+/*
+ * mxuport_unthrottle - unthrottle function of driver
+ *
+ * This function is called by the tty driver when it wants to resume
+ * the data being read from the port. Tell the device it can resume
+ * sending us received data from the port.
+ */
+static void mxuport_unthrottle(struct tty_struct *tty)
+{
+
+	struct usb_serial_port *port = tty->driver_data;
+	struct usb_serial *serial = port->serial;
+
+	dev_dbg(&port->dev, "%s\n", __func__);
+
+	mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_RX_HOST_EN,
+			      1, port->port_number);
+}
+
+/*
+ * Processes one chunk of data received for a port.  Mostly a copy of
+ * usb_serial_generic_process_read_urb().
+ */
+static void mxuport_process_read_urb_data(struct usb_serial_port *port,
+					  char *data, int size)
+{
+	int i;
+
+	if (!port->port.console || !port->sysrq) {
+		tty_insert_flip_string(&port->port, data, size);
+	} else {
+		for (i = 0; i < size; i++, data++) {
+			if (!usb_serial_handle_sysrq_char(port, *data))
+				tty_insert_flip_char(&port->port, *data,
+						     TTY_NORMAL);
+		}
+	}
+	tty_flip_buffer_push(&port->port);
+}
+
+static void mxuport_msr_event(struct usb_serial_port *port, u8 buf[4])
+{
+	struct mxuport_port *mxport = usb_get_serial_port_data(port);
+	u8 rcv_msr_hold = buf[2] & 0xF0;
+	u16 rcv_msr_event = get_unaligned_be16(buf);
+	unsigned long flags;
+
+	if (rcv_msr_event == 0)
+		return;
+
+	/* Update MSR status */
+	spin_lock_irqsave(&mxport->spinlock, flags);
+
+	dev_dbg(&port->dev, "%s - current MSR status = 0x%x\n",
+		__func__, mxport->msr_state);
+
+	if (rcv_msr_hold & UART_MSR_CTS) {
+		mxport->msr_state |= UART_MSR_CTS;
+		dev_dbg(&port->dev, "%s - CTS high\n", __func__);
+	} else {
+		mxport->msr_state &= ~UART_MSR_CTS;
+		dev_dbg(&port->dev, "%s - CTS low\n", __func__);
+	}
+
+	if (rcv_msr_hold & UART_MSR_DSR) {
+		mxport->msr_state |= UART_MSR_DSR;
+		dev_dbg(&port->dev, "%s - DSR high\n", __func__);
+	} else {
+		mxport->msr_state &= ~UART_MSR_DSR;
+		dev_dbg(&port->dev, "%s - DSR low\n", __func__);
+	}
+
+	if (rcv_msr_hold & UART_MSR_DCD) {
+		mxport->msr_state |= UART_MSR_DCD;
+		dev_dbg(&port->dev, "%s - DCD high\n", __func__);
+	} else {
+		mxport->msr_state &= ~UART_MSR_DCD;
+		dev_dbg(&port->dev, "%s - DCD low\n", __func__);
+	}
+	spin_unlock_irqrestore(&mxport->spinlock, flags);
+
+	if (rcv_msr_event &
+	    (SERIAL_EV_CTS | SERIAL_EV_DSR | SERIAL_EV_RLSD)) {
+
+		if (rcv_msr_event & SERIAL_EV_CTS) {
+			port->icount.cts++;
+			dev_dbg(&port->dev, "%s - CTS change\n", __func__);
+		}
+
+		if (rcv_msr_event & SERIAL_EV_DSR) {
+			port->icount.dsr++;
+			dev_dbg(&port->dev, "%s - DSR change\n", __func__);
+		}
+
+		if (rcv_msr_event & SERIAL_EV_RLSD) {
+			port->icount.dcd++;
+			dev_dbg(&port->dev, "%s - DCD change\n", __func__);
+		}
+		wake_up_interruptible(&port->port.delta_msr_wait);
+	}
+}
+
+static void mxuport_lsr_event(struct usb_serial_port *port, u8 buf[4])
+{
+	u8 lsr_event = buf[2];
+
+	if (lsr_event & UART_LSR_BI) {
+		port->icount.brk++;
+		dev_dbg(&port->dev, "%s - break error\n", __func__);
+	}
+
+	if (lsr_event & UART_LSR_FE) {
+		port->icount.frame++;
+		dev_dbg(&port->dev, "%s - frame error\n", __func__);
+	}
+
+	if (lsr_event & UART_LSR_PE) {
+		port->icount.parity++;
+		dev_dbg(&port->dev, "%s - parity error\n", __func__);
+	}
+
+	if (lsr_event & UART_LSR_OE) {
+		port->icount.overrun++;
+		dev_dbg(&port->dev, "%s - overrun error\n", __func__);
+	}
+}
+
+/*
+ * When something interesting happens, modem control lines XON/XOFF
+ * etc, the device sends an event. Process these events.
+ */
+static void mxuport_process_read_urb_event(struct usb_serial_port *port,
+					   u8 buf[4], u32 event)
+{
+	dev_dbg(&port->dev, "%s - receive event : %04x\n", __func__, event);
+
+	switch (event) {
+	case UPORT_EVENT_SEND_NEXT:
+		/*
+		 * Sent as part of the flow control on device buffers.
+		 * Not currently used.
+		 */
+		break;
+	case UPORT_EVENT_MSR:
+		mxuport_msr_event(port, buf);
+		break;
+	case UPORT_EVENT_LSR:
+		mxuport_lsr_event(port, buf);
+		break;
+	case UPORT_EVENT_MCR:
+		/*
+		 * Event to indicate a change in XON/XOFF from the
+		 * peer.  Currently not used. We just continue
+		 * sending the device data and it will buffer it if
+		 * needed. This event could be used for flow control
+		 * between the host and the device.
+		 */
+		break;
+	default:
+		dev_dbg(&port->dev, "Unexpected event\n");
+		break;
+	}
+}
+
+/*
+ * One URB can contain data for multiple ports. Demultiplex the data,
+ * checking the port exists, is opened and the message is valid.
+ */
+static void mxuport_process_read_urb_demux_data(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	struct usb_serial *serial = port->serial;
+	u8 *data = urb->transfer_buffer;
+	u8 *end = data + urb->actual_length;
+	struct usb_serial_port *demux_port;
+	u8 *ch;
+	u16 rcv_port;
+	u16 rcv_len;
+
+	while (data < end) {
+		if (data + HEADER_SIZE > end) {
+			dev_warn(&port->dev, "%s - message with short header\n",
+				 __func__);
+			return;
+		}
+
+		rcv_port = get_unaligned_be16(data);
+		if (rcv_port >= serial->num_ports) {
+			dev_warn(&port->dev, "%s - message for invalid port\n",
+				 __func__);
+			return;
+		}
+
+		demux_port = serial->port[rcv_port];
+		rcv_len = get_unaligned_be16(data + 2);
+		if (!rcv_len || data + HEADER_SIZE + rcv_len > end) {
+			dev_warn(&port->dev, "%s - short data\n", __func__);
+			return;
+		}
+
+		if (test_bit(ASYNCB_INITIALIZED, &demux_port->port.flags)) {
+			ch = data + HEADER_SIZE;
+			mxuport_process_read_urb_data(demux_port, ch, rcv_len);
+		} else {
+			dev_dbg(&demux_port->dev, "%s - data for closed port\n",
+				__func__);
+		}
+		data += HEADER_SIZE + rcv_len;
+	}
+}
+
+/*
+ * One URB can contain events for multiple ports. Demultiplex the event,
+ * checking the port exists, and is opened.
+ */
+static void mxuport_process_read_urb_demux_event(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	struct usb_serial *serial = port->serial;
+	u8 *data = urb->transfer_buffer;
+	u8 *end = data + urb->actual_length;
+	struct usb_serial_port *demux_port;
+	u8 *ch;
+	u16 rcv_port;
+	u16 rcv_event;
+
+	while (data < end) {
+		if (data + EVENT_LENGTH > end) {
+			dev_warn(&port->dev, "%s - message with short event\n",
+				 __func__);
+			return;
+		}
+
+		rcv_port = get_unaligned_be16(data);
+		if (rcv_port >= serial->num_ports) {
+			dev_warn(&port->dev, "%s - message for invalid port\n",
+				 __func__);
+			return;
+		}
+
+		demux_port = serial->port[rcv_port];
+		if (test_bit(ASYNCB_INITIALIZED, &demux_port->port.flags)) {
+			ch = data + HEADER_SIZE;
+			rcv_event = get_unaligned_be16(data + 2);
+			mxuport_process_read_urb_event(demux_port, ch,
+						       rcv_event);
+		} else {
+			dev_dbg(&demux_port->dev,
+				"%s - event for closed port\n", __func__);
+		}
+		data += EVENT_LENGTH;
+	}
+}
+
+/*
+ * This is called when we have received data on the bulk in
+ * endpoint. Depending on which port it was received on, it can
+ * contain serial data or events.
+ */
+static void mxuport_process_read_urb(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	struct usb_serial *serial = port->serial;
+
+	if (port == serial->port[0])
+		mxuport_process_read_urb_demux_data(urb);
+
+	if (port == serial->port[1])
+		mxuport_process_read_urb_demux_event(urb);
+}
+
+/*
+ * Ask the device how many bytes it has queued to be sent out. If
+ * there are none, return true.
+ */
+static bool mxuport_tx_empty(struct usb_serial_port *port)
+{
+	struct usb_serial *serial = port->serial;
+	bool is_empty = true;
+	u32 txlen;
+	u8 *len_buf;
+	int err;
+
+	len_buf = kzalloc(4, GFP_KERNEL);
+	if (!len_buf)
+		goto out;
+
+	err = mxuport_recv_ctrl_urb(serial, RQ_VENDOR_GET_OUTQUEUE, 0,
+				    port->port_number, len_buf, 4);
+	if (err < 0)
+		goto out;
+
+	txlen = get_unaligned_be32(len_buf);
+	dev_dbg(&port->dev, "%s - tx len = %u\n", __func__, txlen);
+
+	if (txlen != 0)
+		is_empty = false;
+
+out:
+	kfree(len_buf);
+	return is_empty;
+}
+
+static int mxuport_set_mcr(struct usb_serial_port *port, u8 mcr_state)
+{
+	struct usb_serial *serial = port->serial;
+	int err;
+
+	dev_dbg(&port->dev, "%s - %02x\n", __func__, mcr_state);
+
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_MCR,
+				    mcr_state, port->port_number);
+	if (err)
+		dev_err(&port->dev, "%s - failed to change MCR\n", __func__);
+
+	return err;
+}
+
+static int mxuport_set_dtr(struct usb_serial_port *port, int on)
+{
+	struct mxuport_port *mxport = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	int err;
+
+	mutex_lock(&mxport->mutex);
+
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_DTR,
+				    !!on, port->port_number);
+	if (!err) {
+		if (on)
+			mxport->mcr_state |= UART_MCR_DTR;
+		else
+			mxport->mcr_state &= ~UART_MCR_DTR;
+	}
+
+	mutex_unlock(&mxport->mutex);
+
+	return err;
+}
+
+static int mxuport_set_rts(struct usb_serial_port *port, u8 state)
+{
+	struct mxuport_port *mxport = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	int err;
+	u8 mcr_state;
+
+	mutex_lock(&mxport->mutex);
+	mcr_state = mxport->mcr_state;
+
+	switch (state) {
+	case MX_RTS_DISABLE:
+		mcr_state &= ~UART_MCR_RTS;
+		break;
+	case MX_RTS_ENABLE:
+		mcr_state |= UART_MCR_RTS;
+		break;
+	case MX_RTS_HW:
+		/*
+		 * Do not update mxport->mcr_state when doing hardware
+		 * flow control.
+		 */
+		break;
+	default:
+		/*
+		 * Should not happen, but somebody might try passing
+		 * MX_RTS_NO_CHANGE, which is not valid.
+		 */
+		err = -EINVAL;
+		goto out;
+	}
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_RTS,
+				    state, port->port_number);
+	if (!err)
+		mxport->mcr_state = mcr_state;
+
+out:
+	mutex_unlock(&mxport->mutex);
+
+	return err;
+}
+
+static void mxuport_dtr_rts(struct usb_serial_port *port, int on)
+{
+	struct mxuport_port *mxport = usb_get_serial_port_data(port);
+	u8 mcr_state;
+	int err;
+
+	mutex_lock(&mxport->mutex);
+	mcr_state = mxport->mcr_state;
+
+	if (on)
+		mcr_state |= (UART_MCR_RTS | UART_MCR_DTR);
+	else
+		mcr_state &= ~(UART_MCR_RTS | UART_MCR_DTR);
+
+	err = mxuport_set_mcr(port, mcr_state);
+	if (!err)
+		mxport->mcr_state = mcr_state;
+
+	mutex_unlock(&mxport->mutex);
+}
+
+static int mxuport_tiocmset(struct tty_struct *tty, unsigned int set,
+			    unsigned int clear)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct mxuport_port *mxport = usb_get_serial_port_data(port);
+	int err;
+	u8 mcr_state;
+
+	mutex_lock(&mxport->mutex);
+	mcr_state = mxport->mcr_state;
+
+	if (set & TIOCM_RTS)
+		mcr_state |= UART_MCR_RTS;
+
+	if (set & TIOCM_DTR)
+		mcr_state |= UART_MCR_DTR;
+
+	if (clear & TIOCM_RTS)
+		mcr_state &= ~UART_MCR_RTS;
+
+	if (clear & TIOCM_DTR)
+		mcr_state &= ~UART_MCR_DTR;
+
+	err = mxuport_set_mcr(port, mcr_state);
+	if (!err)
+		mxport->mcr_state = mcr_state;
+
+	mutex_unlock(&mxport->mutex);
+
+	return err;
+}
+
+static int mxuport_tiocmget(struct tty_struct *tty)
+{
+	struct mxuport_port *mxport;
+	struct usb_serial_port *port = tty->driver_data;
+	unsigned int result;
+	unsigned long flags;
+	unsigned int msr;
+	unsigned int mcr;
+
+	mxport = usb_get_serial_port_data(port);
+
+	mutex_lock(&mxport->mutex);
+	spin_lock_irqsave(&mxport->spinlock, flags);
+
+	msr = mxport->msr_state;
+	mcr = mxport->mcr_state;
+
+	spin_unlock_irqrestore(&mxport->spinlock, flags);
+	mutex_unlock(&mxport->mutex);
+
+	result = (((mcr & UART_MCR_DTR) ? TIOCM_DTR : 0) |	/* 0x002 */
+		  ((mcr & UART_MCR_RTS) ? TIOCM_RTS : 0) |	/* 0x004 */
+		  ((msr & UART_MSR_CTS) ? TIOCM_CTS : 0) |	/* 0x020 */
+		  ((msr & UART_MSR_DCD) ? TIOCM_CAR : 0) |	/* 0x040 */
+		  ((msr & UART_MSR_RI) ? TIOCM_RI : 0) |	/* 0x080 */
+		  ((msr & UART_MSR_DSR) ? TIOCM_DSR : 0));	/* 0x100 */
+
+	dev_dbg(&port->dev, "%s - 0x%04x\n", __func__, result);
+
+	return result;
+}
+
+static int mxuport_set_termios_flow(struct tty_struct *tty,
+				    struct ktermios *old_termios,
+				    struct usb_serial_port *port,
+				    struct usb_serial *serial)
+{
+	u8 xon = START_CHAR(tty);
+	u8 xoff = STOP_CHAR(tty);
+	int enable;
+	int err;
+	u8 *buf;
+	u8 rts;
+
+	buf = kmalloc(2, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* S/W flow control settings */
+	if (I_IXOFF(tty) || I_IXON(tty)) {
+		enable = 1;
+		buf[0] = xon;
+		buf[1] = xoff;
+
+		err = mxuport_send_ctrl_data_urb(serial, RQ_VENDOR_SET_CHARS,
+						 0, port->port_number,
+						 buf, 2);
+		if (err)
+			goto out;
+
+		dev_dbg(&port->dev, "%s - XON = 0x%02x, XOFF = 0x%02x\n",
+			__func__, xon, xoff);
+	} else {
+		enable = 0;
+	}
+
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_XONXOFF,
+				    enable, port->port_number);
+	if (err)
+		goto out;
+
+	rts = MX_RTS_NO_CHANGE;
+
+	/* H/W flow control settings */
+	if (!old_termios ||
+	    C_CRTSCTS(tty) != (old_termios->c_cflag & CRTSCTS)) {
+		if (C_CRTSCTS(tty))
+			rts = MX_RTS_HW;
+		else
+			rts = MX_RTS_ENABLE;
+	}
+
+	if (C_BAUD(tty)) {
+		if (old_termios && (old_termios->c_cflag & CBAUD) == B0) {
+			/* Raise DTR and RTS */
+			if (C_CRTSCTS(tty))
+				rts = MX_RTS_HW;
+			else
+				rts = MX_RTS_ENABLE;
+			mxuport_set_dtr(port, 1);
+		}
+	} else {
+		/* Drop DTR and RTS */
+		rts = MX_RTS_DISABLE;
+		mxuport_set_dtr(port, 0);
+	}
+
+	if (rts != MX_RTS_NO_CHANGE)
+		err = mxuport_set_rts(port, rts);
+
+out:
+	kfree(buf);
+	return err;
+}
+
+static void mxuport_set_termios(struct tty_struct *tty,
+				struct usb_serial_port *port,
+				struct ktermios *old_termios)
+{
+	struct usb_serial *serial = port->serial;
+	u8 *buf;
+	u8 data_bits;
+	u8 stop_bits;
+	u8 parity;
+	int baud;
+	int err;
+
+	if (old_termios &&
+	    !tty_termios_hw_change(&tty->termios, old_termios) &&
+	    tty->termios.c_iflag == old_termios->c_iflag) {
+		dev_dbg(&port->dev, "%s - nothing to change\n", __func__);
+		return;
+	}
+
+	buf = kmalloc(4, GFP_KERNEL);
+	if (!buf)
+		return;
+
+	/* Set data bit of termios */
+	switch (C_CSIZE(tty)) {
+	case CS5:
+		data_bits = MX_WORDLENGTH_5;
+		break;
+	case CS6:
+		data_bits = MX_WORDLENGTH_6;
+		break;
+	case CS7:
+		data_bits = MX_WORDLENGTH_7;
+		break;
+	case CS8:
+	default:
+		data_bits = MX_WORDLENGTH_8;
+		break;
+	}
+
+	/* Set parity of termios */
+	if (C_PARENB(tty)) {
+		if (C_CMSPAR(tty)) {
+			if (C_PARODD(tty))
+				parity = MX_PARITY_MARK;
+			else
+				parity = MX_PARITY_SPACE;
+		} else {
+			if (C_PARODD(tty))
+				parity = MX_PARITY_ODD;
+			else
+				parity = MX_PARITY_EVEN;
+		}
+	} else {
+		parity = MX_PARITY_NONE;
+	}
+
+	/* Set stop bit of termios */
+	if (C_CSTOPB(tty))
+		stop_bits = MX_STOP_BITS_2;
+	else
+		stop_bits = MX_STOP_BITS_1;
+
+	buf[0] = data_bits;
+	buf[1] = parity;
+	buf[2] = stop_bits;
+	buf[3] = 0;
+
+	err = mxuport_send_ctrl_data_urb(serial, RQ_VENDOR_SET_LINE,
+					 0, port->port_number, buf, 4);
+	if (err)
+		goto out;
+
+	err = mxuport_set_termios_flow(tty, old_termios, port, serial);
+	if (err)
+		goto out;
+
+	baud = tty_get_baud_rate(tty);
+	if (!baud)
+		baud = 9600;
+
+	/* Note: Little Endian */
+	put_unaligned_le32(baud, buf);
+
+	err = mxuport_send_ctrl_data_urb(serial, RQ_VENDOR_SET_BAUD,
+					 0, port->port_number,
+					 buf, 4);
+	if (err)
+		goto out;
+
+	dev_dbg(&port->dev, "baud_rate	: %d\n", baud);
+	dev_dbg(&port->dev, "data_bits	: %d\n", data_bits);
+	dev_dbg(&port->dev, "parity	: %d\n", parity);
+	dev_dbg(&port->dev, "stop_bits	: %d\n", stop_bits);
+
+out:
+	kfree(buf);
+}
+
+/*
+ * Determine how many ports this device has dynamically.  It will be
+ * called after the probe() callback is called, but before attach().
+ */
+static int mxuport_calc_num_ports(struct usb_serial *serial)
+{
+	unsigned long features = (unsigned long)usb_get_serial_data(serial);
+
+	if (features & MX_UPORT_2_PORT)
+		return 2;
+	if (features & MX_UPORT_4_PORT)
+		return 4;
+	if (features & MX_UPORT_8_PORT)
+		return 8;
+	if (features & MX_UPORT_16_PORT)
+		return 16;
+
+	return 0;
+}
+
+/* Get the version of the firmware currently running. */
+static int mxuport_get_fw_version(struct usb_serial *serial, u32 *version)
+{
+	u8 *ver_buf;
+	int err;
+
+	ver_buf = kzalloc(4, GFP_KERNEL);
+	if (!ver_buf)
+		return -ENOMEM;
+
+	/* Get firmware version from SDRAM */
+	err = mxuport_recv_ctrl_urb(serial, RQ_VENDOR_GET_VERSION, 0, 0,
+				    ver_buf, 4);
+	if (err != 4) {
+		err = -EIO;
+		goto out;
+	}
+
+	*version = (ver_buf[0] << 16) | (ver_buf[1] << 8) | ver_buf[2];
+	err = 0;
+out:
+	kfree(ver_buf);
+	return err;
+}
+
+/* Given a firmware blob, download it to the device. */
+static int mxuport_download_fw(struct usb_serial *serial,
+			       const struct firmware *fw_p)
+{
+	u8 *fw_buf;
+	size_t txlen;
+	size_t fwidx;
+	int err;
+
+	fw_buf = kmalloc(DOWN_BLOCK_SIZE, GFP_KERNEL);
+	if (!fw_buf)
+		return -ENOMEM;
+
+	dev_dbg(&serial->interface->dev, "Starting firmware download...\n");
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_START_FW_DOWN, 0, 0);
+	if (err)
+		goto out;
+
+	fwidx = 0;
+	do {
+		txlen = min_t(size_t, (fw_p->size - fwidx), DOWN_BLOCK_SIZE);
+
+		memcpy(fw_buf, &fw_p->data[fwidx], txlen);
+		err = mxuport_send_ctrl_data_urb(serial, RQ_VENDOR_FW_DATA,
+						 0, 0, fw_buf, txlen);
+		if (err) {
+			mxuport_send_ctrl_urb(serial, RQ_VENDOR_STOP_FW_DOWN,
+					      0, 0);
+			goto out;
+		}
+
+		fwidx += txlen;
+		usleep_range(1000, 2000);
+
+	} while (fwidx < fw_p->size);
+
+	msleep(1000);
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_STOP_FW_DOWN, 0, 0);
+	if (err)
+		goto out;
+
+	msleep(1000);
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_QUERY_FW_READY, 0, 0);
+
+out:
+	kfree(fw_buf);
+	return err;
+}
+
+static int mxuport_probe(struct usb_serial *serial,
+			 const struct usb_device_id *id)
+{
+	u16 productid = le16_to_cpu(serial->dev->descriptor.idProduct);
+	const struct firmware *fw_p = NULL;
+	u32 version;
+	int local_ver;
+	char buf[32];
+	int err;
+
+	/* Load our firmware */
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_QUERY_FW_CONFIG, 0, 0);
+	if (err) {
+		mxuport_send_ctrl_urb(serial, RQ_VENDOR_RESET_DEVICE, 0, 0);
+		return err;
+	}
+
+	err = mxuport_get_fw_version(serial, &version);
+	if (err < 0)
+		return err;
+
+	dev_dbg(&serial->interface->dev, "Device firmware version v%x.%x.%x\n",
+		(version & 0xff0000) >> 16,
+		(version & 0xff00) >> 8,
+		(version & 0xff));
+
+	snprintf(buf, sizeof(buf) - 1, "moxa/moxa-%04x.fw", productid);
+
+	err = request_firmware(&fw_p, buf, &serial->interface->dev);
+	if (err) {
+		dev_warn(&serial->interface->dev, "Firmware %s not found\n",
+			 buf);
+
+		/* Use the firmware already in the device */
+		err = 0;
+	} else {
+		local_ver = ((fw_p->data[VER_ADDR_1] << 16) |
+			     (fw_p->data[VER_ADDR_2] << 8) |
+			     fw_p->data[VER_ADDR_3]);
+		dev_dbg(&serial->interface->dev,
+			"Available firmware version v%x.%x.%x\n",
+			fw_p->data[VER_ADDR_1], fw_p->data[VER_ADDR_2],
+			fw_p->data[VER_ADDR_3]);
+		if (local_ver > version) {
+			err = mxuport_download_fw(serial, fw_p);
+			if (err)
+				goto out;
+			err  = mxuport_get_fw_version(serial, &version);
+			if (err < 0)
+				goto out;
+		}
+	}
+
+	dev_info(&serial->interface->dev,
+		 "Using device firmware version v%x.%x.%x\n",
+		 (version & 0xff0000) >> 16,
+		 (version & 0xff00) >> 8,
+		 (version & 0xff));
+
+	/*
+	 * Contains the features of this hardware. Store away for
+	 * later use, eg, number of ports.
+	 */
+	usb_set_serial_data(serial, (void *)id->driver_info);
+out:
+	if (fw_p)
+		release_firmware(fw_p);
+	return err;
+}
+
+
+static int mxuport_port_probe(struct usb_serial_port *port)
+{
+	struct usb_serial *serial = port->serial;
+	struct mxuport_port *mxport;
+	int err;
+
+	mxport = devm_kzalloc(&port->dev, sizeof(struct mxuport_port),
+			      GFP_KERNEL);
+	if (!mxport)
+		return -ENOMEM;
+
+	mutex_init(&mxport->mutex);
+	spin_lock_init(&mxport->spinlock);
+
+	/* Set the port private data */
+	usb_set_serial_port_data(port, mxport);
+
+	/* Set FIFO (Enable) */
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_FIFO_DISABLE,
+				    0, port->port_number);
+	if (err)
+		return err;
+
+	/* Set transmission mode (Hi-Performance) */
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_HIGH_PERFOR,
+				    0, port->port_number);
+	if (err)
+		return err;
+
+	/* Set interface (RS-232) */
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_INTERFACE,
+				    MX_INT_RS232,
+				    port->port_number);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int mxuport_alloc_write_urb(struct usb_serial *serial,
+				   struct usb_serial_port *port,
+				   struct usb_serial_port *port0,
+				   int j)
+{
+	struct usb_device *dev = interface_to_usbdev(serial->interface);
+
+	set_bit(j, &port->write_urbs_free);
+	port->write_urbs[j] = usb_alloc_urb(0, GFP_KERNEL);
+	if (!port->write_urbs[j])
+		return -ENOMEM;
+
+	port->bulk_out_buffers[j] = kmalloc(port0->bulk_out_size, GFP_KERNEL);
+	if (!port->bulk_out_buffers[j])
+		return -ENOMEM;
+
+	usb_fill_bulk_urb(port->write_urbs[j], dev,
+			  usb_sndbulkpipe(dev, port->bulk_out_endpointAddress),
+			  port->bulk_out_buffers[j],
+			  port->bulk_out_size,
+			  serial->type->write_bulk_callback,
+			  port);
+	return 0;
+}
+
+
+static int mxuport_alloc_write_urbs(struct usb_serial *serial,
+				    struct usb_serial_port *port,
+				    struct usb_serial_port *port0)
+{
+	int j;
+	int ret;
+
+	for (j = 0; j < ARRAY_SIZE(port->write_urbs); ++j) {
+		ret = mxuport_alloc_write_urb(serial, port, port0, j);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+
+static int mxuport_attach(struct usb_serial *serial)
+{
+	struct usb_serial_port *port0 = serial->port[0];
+	struct usb_serial_port *port1 = serial->port[1];
+	struct usb_serial_port *port;
+	int err;
+	int i;
+	int j;
+
+	/*
+	 * Throw away all but the first allocated write URBs so we can
+	 * set them up again to fit the multiplexing scheme.
+	 */
+	for (i = 1; i < serial->num_bulk_out; ++i) {
+		port = serial->port[i];
+		for (j = 0; j < ARRAY_SIZE(port->write_urbs); ++j) {
+			usb_free_urb(port->write_urbs[j]);
+			kfree(port->bulk_out_buffers[j]);
+			port->write_urbs[j] = NULL;
+			port->bulk_out_buffers[j] = NULL;
+		}
+		port->write_urbs_free = 0;
+	}
+
+	/*
+	 * All write data is sent over the first bulk out endpoint,
+	 * with an added header to indicate the port. Allocate URBs
+	 * for each port to the first bulk out endpoint.
+	 */
+	for (i = 1; i < serial->num_ports; ++i) {
+		port = serial->port[i];
+		port->bulk_out_size = port0->bulk_out_size;
+		port->bulk_out_endpointAddress =
+			port0->bulk_out_endpointAddress;
+
+		err = mxuport_alloc_write_urbs(serial, port, port0);
+		if (err)
+			return err;
+
+		port->write_urb = port->write_urbs[0];
+		port->bulk_out_buffer = port->bulk_out_buffers[0];
+
+		/*
+		 * Ensure each port has a fifo. The framework only
+		 * allocates a fifo to ports with a bulk out endpoint,
+		 * where as we need one for every port.
+		 */
+		if (!kfifo_initialized(&port->write_fifo)) {
+			err = kfifo_alloc(&port->write_fifo, PAGE_SIZE,
+					  GFP_KERNEL);
+			if (err)
+				return err;
+		}
+	}
+
+	/*
+	 * All data from the ports is received on the first bulk in
+	 * endpoint, with a multiplex header. The second bulk in is
+	 * used for events.
+	 *
+	 * Start to read from the device.
+	 */
+	err = usb_serial_generic_submit_read_urbs(port0, GFP_KERNEL);
+	if (err)
+		return err;
+
+	err = usb_serial_generic_submit_read_urbs(port1, GFP_KERNEL);
+	if (err) {
+		usb_serial_generic_close(port0);
+		return err;
+	}
+
+	return 0;
+}
+
+static int mxuport_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	struct mxuport_port *mxport = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	int err;
+
+	/* Set receive host (enable) */
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_RX_HOST_EN,
+				    1, port->port_number);
+	if (err)
+		return err;
+
+	err = mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_OPEN,
+				    1, port->port_number);
+	if (err) {
+		mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_RX_HOST_EN,
+				      0, port->port_number);
+		return err;
+	}
+
+	/* Initial port termios */
+	mxuport_set_termios(tty, port, NULL);
+
+	/*
+	 * TODO: use RQ_VENDOR_GET_MSR, once we know what it
+	 * returns.
+	 */
+	mxport->msr_state = 0;
+
+	return err;
+}
+
+static void mxuport_close(struct usb_serial_port *port)
+{
+	struct usb_serial *serial = port->serial;
+
+	mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_OPEN, 0,
+			      port->port_number);
+
+	mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_RX_HOST_EN, 0,
+			      port->port_number);
+}
+
+/* Send a break to the port. */
+static void mxuport_break_ctl(struct tty_struct *tty, int break_state)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct usb_serial *serial = port->serial;
+	int enable;
+
+	if (break_state == -1) {
+		enable = 1;
+		dev_dbg(&port->dev, "%s - sending break\n", __func__);
+	} else {
+		enable = 0;
+		dev_dbg(&port->dev, "%s - clearing break\n", __func__);
+	}
+
+	mxuport_send_ctrl_urb(serial, RQ_VENDOR_SET_BREAK,
+			      enable, port->port_number);
+}
+
+static int mxuport_resume(struct usb_serial *serial)
+{
+	struct usb_serial_port *port;
+	int c = 0;
+	int i;
+	int r;
+
+	for (i = 0; i < 2; i++) {
+		port = serial->port[i];
+
+		r = usb_serial_generic_submit_read_urbs(port, GFP_NOIO);
+		if (r < 0)
+			c++;
+	}
+
+	for (i = 0; i < serial->num_ports; i++) {
+		port = serial->port[i];
+		if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
+			continue;
+
+		r = usb_serial_generic_write_start(port, GFP_NOIO);
+		if (r < 0)
+			c++;
+	}
+
+	return c ? -EIO : 0;
+}
+
+static struct usb_serial_driver mxuport_device = {
+	.driver = {
+		.owner =	THIS_MODULE,
+		.name =		"mxuport",
+	},
+	.description		= "MOXA UPort",
+	.id_table		= mxuport_idtable,
+	.num_ports		= 0,
+	.probe			= mxuport_probe,
+	.port_probe		= mxuport_port_probe,
+	.attach			= mxuport_attach,
+	.calc_num_ports		= mxuport_calc_num_ports,
+	.open			= mxuport_open,
+	.close			= mxuport_close,
+	.set_termios		= mxuport_set_termios,
+	.break_ctl		= mxuport_break_ctl,
+	.tx_empty		= mxuport_tx_empty,
+	.tiocmiwait		= usb_serial_generic_tiocmiwait,
+	.get_icount		= usb_serial_generic_get_icount,
+	.throttle		= mxuport_throttle,
+	.unthrottle		= mxuport_unthrottle,
+	.tiocmget		= mxuport_tiocmget,
+	.tiocmset		= mxuport_tiocmset,
+	.dtr_rts		= mxuport_dtr_rts,
+	.process_read_urb	= mxuport_process_read_urb,
+	.prepare_write_buffer	= mxuport_prepare_write_buffer,
+	.resume			= mxuport_resume,
+};
+
+static struct usb_serial_driver *const serial_drivers[] = {
+	&mxuport_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, mxuport_idtable);
+
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
+MODULE_AUTHOR("<support@moxa.com>");
+MODULE_LICENSE("GPL");