drivers/usb/serial/generic.c - linux - Git at Google

 /*
  * USB Serial Converter Generic functions
  *
  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License version
  *	2 as published by the Free Software Foundation.
  *
  */

 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 #include <asm/uaccess.h>


 static int debug;

 #ifdef CONFIG_USB_SERIAL_GENERIC

 static int generic_probe(struct usb_interface *interface,
 			 const struct usb_device_id *id);

 static __u16 vendor  = 0x05f9;
 static __u16 product = 0xffff;

 module_param(vendor, ushort, 0);
 MODULE_PARM_DESC(vendor, "User specified USB idVendor");

 module_param(product, ushort, 0);
 MODULE_PARM_DESC(product, "User specified USB idProduct");

 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */

 /* we want to look at all devices, as the vendor/product id can change
  * depending on the command line argument */
 static struct usb_device_id generic_serial_ids[] = {
 	{.driver_info = 42},
 	{}
 };

 static struct usb_driver generic_driver = {
 	.name =		"usbserial_generic",
 	.probe =	generic_probe,
 	.disconnect =	usb_serial_disconnect,
 	.id_table =	generic_serial_ids,
 	.no_dynamic_id =	1,
 };

 /* All of the device info needed for the Generic Serial Converter */
 struct usb_serial_driver usb_serial_generic_device = {
 	.driver = {
 		.owner =	THIS_MODULE,
 		.name =		"generic",
 	},
 	.id_table =		generic_device_ids,
 	.usb_driver = 		&generic_driver,
 	.num_interrupt_in =	NUM_DONT_CARE,
 	.num_bulk_in =		NUM_DONT_CARE,
 	.num_bulk_out =		NUM_DONT_CARE,
 	.num_ports =		1,
 	.shutdown =		usb_serial_generic_shutdown,
 	.throttle =		usb_serial_generic_throttle,
 	.unthrottle =		usb_serial_generic_unthrottle,
 	.resume =		usb_serial_generic_resume,
 };

 static int generic_probe(struct usb_interface *interface,
 			       const struct usb_device_id *id)
 {
 	const struct usb_device_id *id_pattern;

 	id_pattern = usb_match_id(interface, generic_device_ids);
 	if (id_pattern != NULL)
 		return usb_serial_probe(interface, id);
 	return -ENODEV;
 }
 #endif

 int usb_serial_generic_register (int _debug)
 {
 	int retval = 0;

 	debug = _debug;
 #ifdef CONFIG_USB_SERIAL_GENERIC
 	generic_device_ids[0].idVendor = vendor;
 	generic_device_ids[0].idProduct = product;
 	generic_device_ids[0].match_flags = USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;

 	/* register our generic driver with ourselves */
 	retval = usb_serial_register (&usb_serial_generic_device);
 	if (retval)
 		goto exit;
 	retval = usb_register(&generic_driver);
 	if (retval)
 		usb_serial_deregister(&usb_serial_generic_device);
 exit:
 #endif
 	return retval;
 }

 void usb_serial_generic_deregister (void)
 {
 #ifdef CONFIG_USB_SERIAL_GENERIC
 	/* remove our generic driver */
 	usb_deregister(&generic_driver);
 	usb_serial_deregister (&usb_serial_generic_device);
 #endif
 }

 int usb_serial_generic_open (struct usb_serial_port *port, struct file *filp)
 {
 	struct usb_serial *serial = port->serial;
 	int result = 0;
 	unsigned long flags;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	/* force low_latency on so that our tty_push actually forces the data through,
 	   otherwise it is scheduled, and with high data rates (like with OHCI) data
 	   can get lost. */
 	if (port->tty)
 		port->tty->low_latency = 1;

 	/* clear the throttle flags */
 	spin_lock_irqsave(&port->lock, flags);
 	port->throttled = 0;
 	port->throttle_req = 0;
 	spin_unlock_irqrestore(&port->lock, flags);

 	/* if we have a bulk endpoint, start reading from it */
 	if (serial->num_bulk_in) {
 		/* Start reading from the device */
 		usb_fill_bulk_urb (port->read_urb, serial->dev,
 				   usb_rcvbulkpipe(serial->dev, port->bulk_in_endpointAddress),
 				   port->read_urb->transfer_buffer,
 				   port->read_urb->transfer_buffer_length,
 				   ((serial->type->read_bulk_callback) ?
 				     serial->type->read_bulk_callback :
 				     usb_serial_generic_read_bulk_callback),
 				   port);
 		result = usb_submit_urb(port->read_urb, GFP_KERNEL);
 		if (result)
 			dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
 	}

 	return result;
 }
 EXPORT_SYMBOL_GPL(usb_serial_generic_open);

 static void generic_cleanup (struct usb_serial_port *port)
 {
 	struct usb_serial *serial = port->serial;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	if (serial->dev) {
 		/* shutdown any bulk reads that might be going on */
 		if (serial->num_bulk_out)
 			usb_kill_urb(port->write_urb);
 		if (serial->num_bulk_in)
 			usb_kill_urb(port->read_urb);
 	}
 }

 int usb_serial_generic_resume(struct usb_serial *serial)
 {
 	struct usb_serial_port *port;
 	int i, c = 0, r;

 #ifdef CONFIG_PM
 	/*
 	 * If this is an autoresume, don't submit URBs.
 	 * They will be submitted in the open function instead.
 	 */
 	if (serial->dev->auto_pm)
 		return 0;
 #endif
 	for (i = 0; i < serial->num_ports; i++) {
 		port = serial->port[i];
 		if (port->open_count && port->read_urb) {
 			r = usb_submit_urb(port->read_urb, GFP_NOIO);
 			if (r < 0)
 				c++;
 		}
 	}

 	return c ? -EIO : 0;
 }

 void usb_serial_generic_close (struct usb_serial_port *port, struct file * filp)
 {
 	dbg("%s - port %d", __FUNCTION__, port->number);
 	generic_cleanup (port);
 }

 int usb_serial_generic_write(struct usb_serial_port *port, const unsigned char *buf, int count)
 {
 	struct usb_serial *serial = port->serial;
 	int result;
 	unsigned char *data;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	if (count == 0) {
 		dbg("%s - write request of 0 bytes", __FUNCTION__);
 		return (0);
 	}

 	/* only do something if we have a bulk out endpoint */
 	if (serial->num_bulk_out) {
 		unsigned long flags;
 		spin_lock_irqsave(&port->lock, flags);
 		if (port->write_urb_busy) {
 			spin_unlock_irqrestore(&port->lock, flags);
 			dbg("%s - already writing", __FUNCTION__);
 			return 0;
 		}
 		port->write_urb_busy = 1;
 		spin_unlock_irqrestore(&port->lock, flags);

 		count = (count > port->bulk_out_size) ? port->bulk_out_size : count;

 		memcpy (port->write_urb->transfer_buffer, buf, count);
 		data = port->write_urb->transfer_buffer;
 		usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, data);

 		/* set up our urb */
 		usb_fill_bulk_urb (port->write_urb, serial->dev,
 				   usb_sndbulkpipe (serial->dev,
 						    port->bulk_out_endpointAddress),
 				   port->write_urb->transfer_buffer, count,
 				   ((serial->type->write_bulk_callback) ?
 				     serial->type->write_bulk_callback :
 				     usb_serial_generic_write_bulk_callback), port);

 		/* send the data out the bulk port */
 		port->write_urb_busy = 1;
 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 		if (result) {
 			dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
 			/* don't have to grab the lock here, as we will retry if != 0 */
 			port->write_urb_busy = 0;
 		} else
 			result = count;

 		return result;
 	}

 	/* no bulk out, so return 0 bytes written */
 	return 0;
 }

 int usb_serial_generic_write_room (struct usb_serial_port *port)
 {
 	struct usb_serial *serial = port->serial;
 	int room = 0;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	if (serial->num_bulk_out) {
 		if (!(port->write_urb_busy))
 			room = port->bulk_out_size;
 	}

 	dbg("%s - returns %d", __FUNCTION__, room);
 	return (room);
 }

 int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
 {
 	struct usb_serial *serial = port->serial;
 	int chars = 0;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	if (serial->num_bulk_out) {
 		if (port->write_urb_busy)
 			chars = port->write_urb->transfer_buffer_length;
 	}

 	dbg("%s - returns %d", __FUNCTION__, chars);
 	return (chars);
 }


 static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
 {
 	struct urb *urb = port->read_urb;
 	struct usb_serial *serial = port->serial;
 	int result;

 	/* Continue reading from device */
 	usb_fill_bulk_urb (urb, serial->dev,
 			   usb_rcvbulkpipe (serial->dev,
 				   	    port->bulk_in_endpointAddress),
 			   urb->transfer_buffer,
 			   urb->transfer_buffer_length,
 			   ((serial->type->read_bulk_callback) ?
 			     serial->type->read_bulk_callback :
 			     usb_serial_generic_read_bulk_callback), port);
 	result = usb_submit_urb(urb, mem_flags);
 	if (result)
 		dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
 }

 /* Push data to tty layer and resubmit the bulk read URB */
 static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
 {
 	struct urb *urb = port->read_urb;
 	struct tty_struct *tty = port->tty;
 	int room;

 	/* Push data to tty */
 	if (tty && urb->actual_length) {
 		room = tty_buffer_request_room(tty, urb->actual_length);
 		if (room) {
 			tty_insert_flip_string(tty, urb->transfer_buffer, room);
 			tty_flip_buffer_push(tty);
 		}
 	}

 	resubmit_read_urb(port, GFP_ATOMIC);
 }

 void usb_serial_generic_read_bulk_callback (struct urb *urb)
 {
 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
 	unsigned char *data = urb->transfer_buffer;
 	int status = urb->status;
 	unsigned long flags;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	if (unlikely(status != 0)) {
 		dbg("%s - nonzero read bulk status received: %d",
 		    __FUNCTION__, status);
 		return;
 	}

 	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);

 	/* Throttle the device if requested by tty */
 	spin_lock_irqsave(&port->lock, flags);
 	if (!(port->throttled = port->throttle_req)) {
 		spin_unlock_irqrestore(&port->lock, flags);
 		flush_and_resubmit_read_urb(port);
 	} else {
 		spin_unlock_irqrestore(&port->lock, flags);
 	}
 }
 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);

 void usb_serial_generic_write_bulk_callback (struct urb *urb)
 {
 	struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
 	int status = urb->status;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	port->write_urb_busy = 0;
 	if (status) {
 		dbg("%s - nonzero write bulk status received: %d",
 		    __FUNCTION__, status);
 		return;
 	}

 	usb_serial_port_softint(port);
 }
 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);

 void usb_serial_generic_throttle (struct usb_serial_port *port)
 {
 	unsigned long flags;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	/* Set the throttle request flag. It will be picked up
 	 * by usb_serial_generic_read_bulk_callback(). */
 	spin_lock_irqsave(&port->lock, flags);
 	port->throttle_req = 1;
 	spin_unlock_irqrestore(&port->lock, flags);
 }

 void usb_serial_generic_unthrottle (struct usb_serial_port *port)
 {
 	int was_throttled;
 	unsigned long flags;

 	dbg("%s - port %d", __FUNCTION__, port->number);

 	/* Clear the throttle flags */
 	spin_lock_irqsave(&port->lock, flags);
 	was_throttled = port->throttled;
 	port->throttled = port->throttle_req = 0;
 	spin_unlock_irqrestore(&port->lock, flags);

 	if (was_throttled) {
 		/* Resume reading from device */
 		resubmit_read_urb(port, GFP_KERNEL);
 	}
 }

 void usb_serial_generic_shutdown (struct usb_serial *serial)
 {
 	int i;

 	dbg("%s", __FUNCTION__);

 	/* stop reads and writes on all ports */
 	for (i=0; i < serial->num_ports; ++i) {
 		generic_cleanup(serial->port[i]);
 	}
 }
	/*
	* USB Serial Converter Generic functions
	*
	* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License version
	* 2 as published by the Free Software Foundation.
	*
	*/

	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/slab.h>
	#include <linux/tty.h>
	#include <linux/tty_flip.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/usb.h>
	#include <linux/usb/serial.h>
	#include <asm/uaccess.h>


	static int debug;

	#ifdef CONFIG_USB_SERIAL_GENERIC

	static int generic_probe(struct usb_interface *interface,
	const struct usb_device_id *id);

	static __u16 vendor = 0x05f9;
	static __u16 product = 0xffff;

	module_param(vendor, ushort, 0);
	MODULE_PARM_DESC(vendor, "User specified USB idVendor");

	module_param(product, ushort, 0);
	MODULE_PARM_DESC(product, "User specified USB idProduct");

	static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */

	/* we want to look at all devices, as the vendor/product id can change
	* depending on the command line argument */
	static struct usb_device_id generic_serial_ids[] = {
	{.driver_info = 42},
	{}
	};

	static struct usb_driver generic_driver = {
	.name = "usbserial_generic",
	.probe = generic_probe,
	.disconnect = usb_serial_disconnect,
	.id_table = generic_serial_ids,
	.no_dynamic_id = 1,
	};

	/* All of the device info needed for the Generic Serial Converter */
	struct usb_serial_driver usb_serial_generic_device = {
	.driver = {
	.owner = THIS_MODULE,
	.name = "generic",
	},
	.id_table = generic_device_ids,
	.usb_driver = &generic_driver,
	.num_interrupt_in = NUM_DONT_CARE,
	.num_bulk_in = NUM_DONT_CARE,
	.num_bulk_out = NUM_DONT_CARE,
	.num_ports = 1,
	.shutdown = usb_serial_generic_shutdown,
	.throttle = usb_serial_generic_throttle,
	.unthrottle = usb_serial_generic_unthrottle,
	.resume = usb_serial_generic_resume,
	};

	static int generic_probe(struct usb_interface *interface,
	const struct usb_device_id *id)
	{
	const struct usb_device_id *id_pattern;

	id_pattern = usb_match_id(interface, generic_device_ids);
	if (id_pattern != NULL)
	return usb_serial_probe(interface, id);
	return -ENODEV;
	}
	#endif

	int usb_serial_generic_register (int _debug)
	{
	int retval = 0;

	debug = _debug;
	#ifdef CONFIG_USB_SERIAL_GENERIC
	generic_device_ids[0].idVendor = vendor;
	generic_device_ids[0].idProduct = product;
	generic_device_ids[0].match_flags = USB_DEVICE_ID_MATCH_VENDOR \| USB_DEVICE_ID_MATCH_PRODUCT;

	/* register our generic driver with ourselves */
	retval = usb_serial_register (&usb_serial_generic_device);
	if (retval)
	goto exit;
	retval = usb_register(&generic_driver);
	if (retval)
	usb_serial_deregister(&usb_serial_generic_device);
	exit:
	#endif
	return retval;
	}

	void usb_serial_generic_deregister (void)
	{
	#ifdef CONFIG_USB_SERIAL_GENERIC
	/* remove our generic driver */
	usb_deregister(&generic_driver);
	usb_serial_deregister (&usb_serial_generic_device);
	#endif
	}

	int usb_serial_generic_open (struct usb_serial_port port, struct file filp)
	{
	struct usb_serial *serial = port->serial;
	int result = 0;
	unsigned long flags;

	dbg("%s - port %d", __FUNCTION__, port->number);

	/* force low_latency on so that our tty_push actually forces the data through,
	otherwise it is scheduled, and with high data rates (like with OHCI) data
	can get lost. */
	if (port->tty)
	port->tty->low_latency = 1;

	/* clear the throttle flags */
	spin_lock_irqsave(&port->lock, flags);
	port->throttled = 0;
	port->throttle_req = 0;
	spin_unlock_irqrestore(&port->lock, flags);

	/* if we have a bulk endpoint, start reading from it */
	if (serial->num_bulk_in) {
	/* Start reading from the device */
	usb_fill_bulk_urb (port->read_urb, serial->dev,
	usb_rcvbulkpipe(serial->dev, port->bulk_in_endpointAddress),
	port->read_urb->transfer_buffer,
	port->read_urb->transfer_buffer_length,
	((serial->type->read_bulk_callback) ?
	serial->type->read_bulk_callback :
	usb_serial_generic_read_bulk_callback),
	port);
	result = usb_submit_urb(port->read_urb, GFP_KERNEL);
	if (result)
	dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
	}

	return result;
	}
	EXPORT_SYMBOL_GPL(usb_serial_generic_open);

	static void generic_cleanup (struct usb_serial_port *port)
	{
	struct usb_serial *serial = port->serial;

	dbg("%s - port %d", __FUNCTION__, port->number);

	if (serial->dev) {
	/* shutdown any bulk reads that might be going on */
	if (serial->num_bulk_out)
	usb_kill_urb(port->write_urb);
	if (serial->num_bulk_in)
	usb_kill_urb(port->read_urb);
	}
	}

	int usb_serial_generic_resume(struct usb_serial *serial)
	{
	struct usb_serial_port *port;
	int i, c = 0, r;

	#ifdef CONFIG_PM
	/*
	* If this is an autoresume, don't submit URBs.
	* They will be submitted in the open function instead.
	*/
	if (serial->dev->auto_pm)
	return 0;
	#endif
	for (i = 0; i < serial->num_ports; i++) {
	port = serial->port[i];
	if (port->open_count && port->read_urb) {
	r = usb_submit_urb(port->read_urb, GFP_NOIO);
	if (r < 0)
	c++;
	}
	}

	return c ? -EIO : 0;
	}

	void usb_serial_generic_close (struct usb_serial_port port, struct file filp)
	{
	dbg("%s - port %d", __FUNCTION__, port->number);
	generic_cleanup (port);
	}

	int usb_serial_generic_write(struct usb_serial_port port, const unsigned char buf, int count)
	{
	struct usb_serial *serial = port->serial;
	int result;
	unsigned char *data;

	dbg("%s - port %d", __FUNCTION__, port->number);

	if (count == 0) {
	dbg("%s - write request of 0 bytes", __FUNCTION__);
	return (0);
	}

	/* only do something if we have a bulk out endpoint */
	if (serial->num_bulk_out) {
	unsigned long flags;
	spin_lock_irqsave(&port->lock, flags);
	if (port->write_urb_busy) {
	spin_unlock_irqrestore(&port->lock, flags);
	dbg("%s - already writing", __FUNCTION__);
	return 0;
	}
	port->write_urb_busy = 1;
	spin_unlock_irqrestore(&port->lock, flags);

	count = (count > port->bulk_out_size) ? port->bulk_out_size : count;

	memcpy (port->write_urb->transfer_buffer, buf, count);
	data = port->write_urb->transfer_buffer;
	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, data);

	/* set up our urb */
	usb_fill_bulk_urb (port->write_urb, serial->dev,
	usb_sndbulkpipe (serial->dev,
	port->bulk_out_endpointAddress),
	port->write_urb->transfer_buffer, count,
	((serial->type->write_bulk_callback) ?
	serial->type->write_bulk_callback :
	usb_serial_generic_write_bulk_callback), port);

	/* send the data out the bulk port */
	port->write_urb_busy = 1;
	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
	if (result) {
	dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
	/* don't have to grab the lock here, as we will retry if != 0 */
	port->write_urb_busy = 0;
	} else
	result = count;

	return result;
	}

	/* no bulk out, so return 0 bytes written */
	return 0;
	}

	int usb_serial_generic_write_room (struct usb_serial_port *port)
	{
	struct usb_serial *serial = port->serial;
	int room = 0;

	dbg("%s - port %d", __FUNCTION__, port->number);

	if (serial->num_bulk_out) {
	if (!(port->write_urb_busy))
	room = port->bulk_out_size;
	}

	dbg("%s - returns %d", __FUNCTION__, room);
	return (room);
	}

	int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
	{
	struct usb_serial *serial = port->serial;
	int chars = 0;

	dbg("%s - port %d", __FUNCTION__, port->number);

	if (serial->num_bulk_out) {
	if (port->write_urb_busy)
	chars = port->write_urb->transfer_buffer_length;
	}

	dbg("%s - returns %d", __FUNCTION__, chars);
	return (chars);
	}


	static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
	{
	struct urb *urb = port->read_urb;
	struct usb_serial *serial = port->serial;
	int result;

	/* Continue reading from device */
	usb_fill_bulk_urb (urb, serial->dev,
	usb_rcvbulkpipe (serial->dev,
	port->bulk_in_endpointAddress),
	urb->transfer_buffer,
	urb->transfer_buffer_length,
	((serial->type->read_bulk_callback) ?
	serial->type->read_bulk_callback :
	usb_serial_generic_read_bulk_callback), port);
	result = usb_submit_urb(urb, mem_flags);
	if (result)
	dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
	}

	/* Push data to tty layer and resubmit the bulk read URB */
	static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
	{
	struct urb *urb = port->read_urb;
	struct tty_struct *tty = port->tty;
	int room;

	/* Push data to tty */
	if (tty && urb->actual_length) {
	room = tty_buffer_request_room(tty, urb->actual_length);
	if (room) {
	tty_insert_flip_string(tty, urb->transfer_buffer, room);
	tty_flip_buffer_push(tty);
	}
	}

	resubmit_read_urb(port, GFP_ATOMIC);
	}

	void usb_serial_generic_read_bulk_callback (struct urb *urb)
	{
	struct usb_serial_port port = (struct usb_serial_port )urb->context;
	unsigned char *data = urb->transfer_buffer;
	int status = urb->status;
	unsigned long flags;

	dbg("%s - port %d", __FUNCTION__, port->number);

	if (unlikely(status != 0)) {
	dbg("%s - nonzero read bulk status received: %d",
	__FUNCTION__, status);
	return;
	}

	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);

	/* Throttle the device if requested by tty */
	spin_lock_irqsave(&port->lock, flags);
	if (!(port->throttled = port->throttle_req)) {
	spin_unlock_irqrestore(&port->lock, flags);
	flush_and_resubmit_read_urb(port);
	} else {
	spin_unlock_irqrestore(&port->lock, flags);
	}
	}
	EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);

	void usb_serial_generic_write_bulk_callback (struct urb *urb)
	{
	struct usb_serial_port port = (struct usb_serial_port )urb->context;
	int status = urb->status;

	dbg("%s - port %d", __FUNCTION__, port->number);

	port->write_urb_busy = 0;
	if (status) {
	dbg("%s - nonzero write bulk status received: %d",
	__FUNCTION__, status);
	return;
	}

	usb_serial_port_softint(port);
	}
	EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);

	void usb_serial_generic_throttle (struct usb_serial_port *port)
	{
	unsigned long flags;

	dbg("%s - port %d", __FUNCTION__, port->number);

	/* Set the throttle request flag. It will be picked up
	* by usb_serial_generic_read_bulk_callback(). */
	spin_lock_irqsave(&port->lock, flags);
	port->throttle_req = 1;
	spin_unlock_irqrestore(&port->lock, flags);
	}

	void usb_serial_generic_unthrottle (struct usb_serial_port *port)
	{
	int was_throttled;
	unsigned long flags;

	dbg("%s - port %d", __FUNCTION__, port->number);

	/* Clear the throttle flags */
	spin_lock_irqsave(&port->lock, flags);
	was_throttled = port->throttled;
	port->throttled = port->throttle_req = 0;
	spin_unlock_irqrestore(&port->lock, flags);

	if (was_throttled) {
	/* Resume reading from device */
	resubmit_read_urb(port, GFP_KERNEL);
	}
	}

	void usb_serial_generic_shutdown (struct usb_serial *serial)
	{
	int i;

	dbg("%s", __FUNCTION__);

	/* stop reads and writes on all ports */
	for (i=0; i < serial->num_ports; ++i) {
	generic_cleanup(serial->port[i]);
	}
	}