text: /*
   * cdc-acm.c
   *
   * Copyright (c) 1999 Armin Fuerst	<fuerst@in.tum.de>
   * Copyright (c) 1999 Pavel Machek	<pavel@ucw.cz>
   * Copyright (c) 1999 Johannes Erdfelt	<johannes@erdfelt.com>
   * Copyright (c) 2000 Vojtech Pavlik	<vojtech@suse.cz>
   * Copyright (c) 2004 Oliver Neukum	<oliver@neukum.name>
   * Copyright (c) 2005 David Kubicek	<dave@awk.cz>
   * Copyright (c) 2011 Johan Hovold	<jhovold@gmail.com>
   *
   * USB Abstract Control Model driver for USB modems and ISDN adapters
   *
   * Sponsored by SuSE
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  #undef DEBUG
  #undef VERBOSE_DEBUG
  
  #include <linux/kernel.h>
  #include <linux/errno.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/tty.h>
  #include <linux/serial.h>
  #include <linux/tty_driver.h>
  #include <linux/tty_flip.h>
  #include <linux/serial.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/uaccess.h>
  #include <linux/usb.h>
  #include <linux/usb/cdc.h>
  #include <asm/byteorder.h>
  #include <asm/unaligned.h>
  #include <linux/list.h>
  
  #include "cdc-acm.h"
  
  
  #define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik, David Kubicek, Johan Hovold"
  #define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"
  
  static struct usb_driver acm_driver;
  static struct tty_driver *acm_tty_driver;
  static struct acm *acm_table[ACM_TTY_MINORS];
  
  static DEFINE_MUTEX(acm_table_lock);
  
  /*
   * acm_table accessors
   */
  
  /*
   * Look up an ACM structure by index. If found and not disconnected, increment
   * its refcount and return it with its mutex held.
   */
  static struct acm *acm_get_by_index(unsigned index)
  {
  	struct acm *acm;
  
  	mutex_lock(&acm_table_lock);
  	acm = acm_table[index];
  	if (acm) {
  		mutex_lock(&acm->mutex);
  		if (acm->disconnected) {
  			mutex_unlock(&acm->mutex);
  			acm = NULL;
  		} else {
  			tty_port_get(&acm->port);
  			mutex_unlock(&acm->mutex);
  		}
  	}
  	mutex_unlock(&acm_table_lock);
  	return acm;
  }
  
  /*
   * Try to find an available minor number and if found, associate it with 'acm'.
   */
  static int acm_alloc_minor(struct acm *acm)
  {
  	int minor;
  
  	mutex_lock(&acm_table_lock);
  	for (minor = 0; minor < ACM_TTY_MINORS; minor++) {
  		if (!acm_table[minor]) {
  			acm_table[minor] = acm;
  			break;
  		}
  	}
  	mutex_unlock(&acm_table_lock);
  
  	return minor;
  }
  
  /* Release the minor number associated with 'acm'.  */
  static void acm_release_minor(struct acm *acm)
  {
  	mutex_lock(&acm_table_lock);
  	acm_table[acm->minor] = NULL;
  	mutex_unlock(&acm_table_lock);
  }
  
  /*
   * Functions for ACM control messages.
   */
  
  static int acm_ctrl_msg(struct acm *acm, int request, int value,
  							void *buf, int len)
  {
  	int retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
  		request, USB_RT_ACM, value,
  		acm->control->altsetting[0].desc.bInterfaceNumber,
  		buf, len, 5000);
  	dev_dbg(&acm->control->dev,
  			"%s - rq 0x%02x, val %#x, len %#x, result %d\n",
  			__func__, request, value, len, retval);
  	return retval < 0 ? retval : 0;
  }
  
  /* devices aren't required to support these requests.
   * the cdc acm descriptor tells whether they do...
   */
  #define acm_set_control(acm, control) \
  	acm_ctrl_msg(acm, USB_CDC_REQ_SET_CONTROL_LINE_STATE, control, NULL, 0)
  #define acm_set_line(acm, line) \
  	acm_ctrl_msg(acm, USB_CDC_REQ_SET_LINE_CODING, 0, line, sizeof *(line))
  #define acm_send_break(acm, ms) \
  	acm_ctrl_msg(acm, USB_CDC_REQ_SEND_BREAK, ms, NULL, 0)
  
  /*
   * Write buffer management.
   * All of these assume proper locks taken by the caller.
   */
  
  static int acm_wb_alloc(struct acm *acm)
  {
  	int i, wbn;
  	struct acm_wb *wb;
  
  	wbn = 0;
  	i = 0;
  	for (;;) {
  		wb = &acm->wb[wbn];
  		if (!wb->use) {
  			wb->use = 1;
  			return wbn;
  		}
  		wbn = (wbn + 1) % ACM_NW;
  		if (++i >= ACM_NW)
  			return -1;
  	}
  }
  
  static int acm_wb_is_avail(struct acm *acm)
  {
  	int i, n;
  	unsigned long flags;
  
  	n = ACM_NW;
  	spin_lock_irqsave(&acm->write_lock, flags);
  	for (i = 0; i < ACM_NW; i++)
  		n -= acm->wb[i].use;
  	spin_unlock_irqrestore(&acm->write_lock, flags);
  	return n;
  }
  
  /*
   * Finish write. Caller must hold acm->write_lock
   */
  static void acm_write_done(struct acm *acm, struct acm_wb *wb)
  {
  	wb->use = 0;
  	acm->transmitting--;
  	usb_autopm_put_interface_async(acm->control);
  }
  
  /*
   * Poke write.
   *
   * the caller is responsible for locking
   */
  
  static int acm_start_wb(struct acm *acm, struct acm_wb *wb)
  {
  	int rc;
  
  	acm->transmitting++;
  
  	wb->urb->transfer_buffer = wb->buf;
  	wb->urb->transfer_dma = wb->dmah;
  	wb->urb->transfer_buffer_length = wb->len;
  	wb->urb->dev = acm->dev;
  
  	rc = usb_submit_urb(wb->urb, GFP_ATOMIC);
  	if (rc < 0) {
  		dev_err(&acm->data->dev,
  			"%s - usb_submit_urb(write bulk) failed: %d\n",
  			__func__, rc);
  		acm_write_done(acm, wb);
  	}
  	return rc;
  }
  
  static int acm_write_start(struct acm *acm, int wbn)
  {
  	unsigned long flags;
  	struct acm_wb *wb = &acm->wb[wbn];
  	int rc;
  
  	spin_lock_irqsave(&acm->write_lock, flags);
  	if (!acm->dev) {
  		wb->use = 0;
  		spin_unlock_irqrestore(&acm->write_lock, flags);
  		return -ENODEV;
  	}
  
  	dev_vdbg(&acm->data->dev, "%s - susp_count %d\n", __func__,
  							acm->susp_count);
  	usb_autopm_get_interface_async(acm->control);
  	if (acm->susp_count) {
  		if (!acm->delayed_wb)
  			acm->delayed_wb = wb;
  		else
  			usb_autopm_put_interface_async(acm->control);
  		spin_unlock_irqrestore(&acm->write_lock, flags);
  		return 0;	/* A white lie */
  	}
  	usb_mark_last_busy(acm->dev);
  
  	rc = acm_start_wb(acm, wb);
  	spin_unlock_irqrestore(&acm->write_lock, flags);
  
  	return rc;
  
  }
  /*
   * attributes exported through sysfs
   */
  static ssize_t show_caps
  (struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct acm *acm = usb_get_intfdata(intf);
  
  	return sprintf(buf, "%d", acm->ctrl_caps);
  }
  static DEVICE_ATTR(bmCapabilities, S_IRUGO, show_caps, NULL);
  
  static ssize_t show_country_codes
  (struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct acm *acm = usb_get_intfdata(intf);
  
  	memcpy(buf, acm->country_codes, acm->country_code_size);
  	return acm->country_code_size;
  }
  
  static DEVICE_ATTR(wCountryCodes, S_IRUGO, show_country_codes, NULL);
  
  static ssize_t show_country_rel_date
  (struct device *dev, struct device_attribute *attr, char *buf)
  {
  	struct usb_interface *intf = to_usb_interface(dev);
  	struct acm *acm = usb_get_intfdata(intf);
  
  	return sprintf(buf, "%d", acm->country_rel_date);
  }
  
  static DEVICE_ATTR(iCountryCodeRelDate, S_IRUGO, show_country_rel_date, NULL);
  /*
   * Interrupt handlers for various ACM device responses
   */
  
  /* control interface reports status changes with "interrupt" transfers */
  static void acm_ctrl_irq(struct urb *urb)
  {
  	struct acm *acm = urb->context;
  	struct usb_cdc_notification *dr = urb->transfer_buffer;
  	struct tty_struct *tty;
  	unsigned char *data;
  	int newctrl;
  	int retval;
  	int status = urb->status;
  
  	switch (status) {
  	case 0:
  		/* success */
  		break;
  	case -ECONNRESET:
  	case -ENOENT:
  	case -ESHUTDOWN:
  		/* this urb is terminated, clean up */
  		dev_dbg(&acm->control->dev,
  				"%s - urb shutting down with status: %d\n",
  				__func__, status);
  		return;
  	default:
  		dev_dbg(&acm->control->dev,
  				"%s - nonzero urb status received: %d\n",
  				__func__, status);
  		goto exit;
  	}
  
  	usb_mark_last_busy(acm->dev);
  
  	data = (unsigned char *)(dr + 1);
  	switch (dr->bNotificationType) {
  	case USB_CDC_NOTIFY_NETWORK_CONNECTION:
  		dev_dbg(&acm->control->dev, "%s - network connection: %d\n",
  							__func__, dr->wValue);
  		break;
  
  	case USB_CDC_NOTIFY_SERIAL_STATE:
  		tty = tty_port_tty_get(&acm->port);
  		newctrl = get_unaligned_le16(data);
  
  		if (tty) {
  			if (!acm->clocal &&
  				(acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
  				dev_dbg(&acm->control->dev,
  					"%s - calling hangup\n", __func__);
  				tty_hangup(tty);
  			}
  			tty_kref_put(tty);
  		}
  
  		acm->ctrlin = newctrl;
  
  		dev_dbg(&acm->control->dev,
  			"%s - input control lines: dcd%c dsr%c break%c "
  			"ring%c framing%c parity%c overrun%c\n",
  			__func__,
  			acm->ctrlin & ACM_CTRL_DCD ? '+' : '-',
  			acm->ctrlin & ACM_CTRL_DSR ? '+' : '-',
  			acm->ctrlin & ACM_CTRL_BRK ? '+' : '-',
  			acm->ctrlin & ACM_CTRL_RI  ? '+' : '-',
  			acm->ctrlin & ACM_CTRL_FRAMING ? '+' : '-',
  			acm->ctrlin & ACM_CTRL_PARITY ? '+' : '-',
  			acm->ctrlin & ACM_CTRL_OVERRUN ? '+' : '-');
  			break;
  
  	default:
  		dev_dbg(&acm->control->dev,
  			"%s - unknown notification %d received: index %d "
  			"len %d data0 %d data1 %d\n",
  			__func__,
  			dr->bNotificationType, dr->wIndex,
  			dr->wLength, data[0], data[1]);
  		break;
  	}
  exit:
  	retval = usb_submit_urb(urb, GFP_ATOMIC);
  	if (retval)
  		dev_err(&acm->control->dev, "%s - usb_submit_urb failed: %d\n",
  							__func__, retval);
  }
  
  static int acm_submit_read_urb(struct acm *acm, int index, gfp_t mem_flags)
  {
  	int res;
  
  	if (!test_and_clear_bit(index, &acm->read_urbs_free))
  		return 0;
  
  	dev_vdbg(&acm->data->dev, "%s - urb %d\n", __func__, index);
  
  	res = usb_submit_urb(acm->read_urbs[index], mem_flags);
  	if (res) {
  		if (res != -EPERM) {
  			dev_err(&acm->data->dev,
  					"%s - usb_submit_urb failed: %d\n",
  					__func__, res);
  		}
  		set_bit(index, &acm->read_urbs_free);
  		return res;
  	}
  
  	return 0;
  }
  
  static int acm_submit_read_urbs(struct acm *acm, gfp_t mem_flags)
  {
  	int res;
  	int i;
  
  	for (i = 0; i < acm->rx_buflimit; ++i) {
  		res = acm_submit_read_urb(acm, i, mem_flags);
  		if (res)
  			return res;
  	}
  
  	return 0;
  }
  
  static void acm_process_read_urb(struct acm *acm, struct urb *urb)
  {
  	struct tty_struct *tty;
  
  	if (!urb->actual_length)
  		return;
  
  	tty = tty_port_tty_get(&acm->port);
  	if (!tty)
  		return;
  
  	tty_insert_flip_string(tty, urb->transfer_buffer, urb->actual_length);
  	tty_flip_buffer_push(tty);
  
  	tty_kref_put(tty);
  }
  
  static void acm_read_bulk_callback(struct urb *urb)
  {
  	struct acm_rb *rb = urb->context;
  	struct acm *acm = rb->instance;
  	unsigned long flags;
  
  	dev_vdbg(&acm->data->dev, "%s - urb %d, len %d\n", __func__,
  					rb->index, urb->actual_length);
  	set_bit(rb->index, &acm->read_urbs_free);
  
  	if (!acm->dev) {
  		dev_dbg(&acm->data->dev, "%s - disconnected\n", __func__);
  		return;
  	}
  	usb_mark_last_busy(acm->dev);
  
  	if (urb->status) {
  		dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n",
  							__func__, urb->status);
  		return;
  	}
  	acm_process_read_urb(acm, urb);
  
  	/* throttle device if requested by tty */
  	spin_lock_irqsave(&acm->read_lock, flags);
  	acm->throttled = acm->throttle_req;
  	if (!acm->throttled && !acm->susp_count) {
  		spin_unlock_irqrestore(&acm->read_lock, flags);
  		acm_submit_read_urb(acm, rb->index, GFP_ATOMIC);
  	} else {
  		spin_unlock_irqrestore(&acm->read_lock, flags);
  	}
  }
  
  /* data interface wrote those outgoing bytes */
  static void acm_write_bulk(struct urb *urb)
  {
  	struct acm_wb *wb = urb->context;
  	struct acm *acm = wb->instance;
  	unsigned long flags;
  
  	if (urb->status	|| (urb->actual_length != urb->transfer_buffer_length))
  		dev_vdbg(&acm->data->dev, "%s - len %d/%d, status %d\n",
  			__func__,
  			urb->actual_length,
  			urb->transfer_buffer_length,
  			urb->status);
  
  	spin_lock_irqsave(&acm->write_lock, flags);
  	acm_write_done(acm, wb);
  	spin_unlock_irqrestore(&acm->write_lock, flags);
  	schedule_work(&acm->work);
  }
  
  static void acm_softint(struct work_struct *work)
  {
  	struct acm *acm = container_of(work, struct acm, work);
  	struct tty_struct *tty;
  
  	dev_vdbg(&acm->data->dev, "%s\n", __func__);
  
  	tty = tty_port_tty_get(&acm->port);
  	if (!tty)
  		return;
  	tty_wakeup(tty);
  	tty_kref_put(tty);
  }
  
  /*
   * TTY handlers
   */
  
  static int acm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
  {
  	struct acm *acm;
  	int retval;
  
  	dev_dbg(tty->dev, "%s\n", __func__);
  
  	acm = acm_get_by_index(tty->index);
  	if (!acm)
  		return -ENODEV;
  
  	retval = tty_standard_install(driver, tty);
  	if (retval)
  		goto error_init_termios;
  
  	tty->driver_data = acm;
  
  	return 0;
  
  error_init_termios:
  	tty_port_put(&acm->port);
  	return retval;
  }
  
  static int acm_tty_open(struct tty_struct *tty, struct file *filp)
  {
  	struct acm *acm = tty->driver_data;
  
  	dev_dbg(tty->dev, "%s\n", __func__);
  
  	return tty_port_open(&acm->port, tty, filp);
  }
  
  static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
  {
  	struct acm *acm = container_of(port, struct acm, port);
  	int retval = -ENODEV;
  
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  
  	mutex_lock(&acm->mutex);
  	if (acm->disconnected)
  		goto disconnected;
  
  	retval = usb_autopm_get_interface(acm->control);
  	if (retval)
  		goto error_get_interface;
  
  	/*
  	 * FIXME: Why do we need this? Allocating 64K of physically contiguous
  	 * memory is really nasty...
  	 */
  	set_bit(TTY_NO_WRITE_SPLIT, &tty->flags);
  	acm->control->needs_remote_wakeup = 1;
  
  	acm->ctrlurb->dev = acm->dev;
  	if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL)) {
  		dev_err(&acm->control->dev,
  			"%s - usb_submit_urb(ctrl irq) failed\n", __func__);
  		goto error_submit_urb;
  	}
  
  	acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS;
  	if (acm_set_control(acm, acm->ctrlout) < 0 &&
  	    (acm->ctrl_caps & USB_CDC_CAP_LINE))
  		goto error_set_control;
  
  	usb_autopm_put_interface(acm->control);
  
  	if (acm_submit_read_urbs(acm, GFP_KERNEL))
  		goto error_submit_read_urbs;
  
  	mutex_unlock(&acm->mutex);
  
  	return 0;
  
  error_submit_read_urbs:
  	acm->ctrlout = 0;
  	acm_set_control(acm, acm->ctrlout);
  error_set_control:
  	usb_kill_urb(acm->ctrlurb);
  error_submit_urb:
  	usb_autopm_put_interface(acm->control);
  error_get_interface:
  disconnected:
  	mutex_unlock(&acm->mutex);
  	return retval;
  }
  
  static void acm_port_destruct(struct tty_port *port)
  {
  	struct acm *acm = container_of(port, struct acm, port);
  
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  
  	tty_unregister_device(acm_tty_driver, acm->minor);
  	acm_release_minor(acm);
  	usb_put_intf(acm->control);
  	kfree(acm->country_codes);
  	kfree(acm);
  }
  
  static void acm_port_shutdown(struct tty_port *port)
  {
  	struct acm *acm = container_of(port, struct acm, port);
  	int i;
  
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  
  	mutex_lock(&acm->mutex);
  	if (!acm->disconnected) {
  		usb_autopm_get_interface(acm->control);
  		acm_set_control(acm, acm->ctrlout = 0);
  		usb_kill_urb(acm->ctrlurb);
  		for (i = 0; i < ACM_NW; i++)
  			usb_kill_urb(acm->wb[i].urb);
  		for (i = 0; i < acm->rx_buflimit; i++)
  			usb_kill_urb(acm->read_urbs[i]);
  		acm->control->needs_remote_wakeup = 0;
  		usb_autopm_put_interface(acm->control);
  	}
  	mutex_unlock(&acm->mutex);
  }
  
  static void acm_tty_cleanup(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  	tty_port_put(&acm->port);
  }
  
  static void acm_tty_hangup(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  	tty_port_hangup(&acm->port);
  }
  
  static void acm_tty_close(struct tty_struct *tty, struct file *filp)
  {
  	struct acm *acm = tty->driver_data;
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  	tty_port_close(&acm->port, tty, filp);
  }
  
  static int acm_tty_write(struct tty_struct *tty,
  					const unsigned char *buf, int count)
  {
  	struct acm *acm = tty->driver_data;
  	int stat;
  	unsigned long flags;
  	int wbn;
  	struct acm_wb *wb;
  
  	if (!count)
  		return 0;
  
  	dev_vdbg(&acm->data->dev, "%s - count %d\n", __func__, count);
  
  	spin_lock_irqsave(&acm->write_lock, flags);
  	wbn = acm_wb_alloc(acm);
  	if (wbn < 0) {
  		spin_unlock_irqrestore(&acm->write_lock, flags);
  		return 0;
  	}
  	wb = &acm->wb[wbn];
  
  	count = (count > acm->writesize) ? acm->writesize : count;
  	dev_vdbg(&acm->data->dev, "%s - write %d\n", __func__, count);
  	memcpy(wb->buf, buf, count);
  	wb->len = count;
  	spin_unlock_irqrestore(&acm->write_lock, flags);
  
  	stat = acm_write_start(acm, wbn);
  	if (stat < 0)
  		return stat;
  	return count;
  }
  
  static int acm_tty_write_room(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  	/*
  	 * Do not let the line discipline to know that we have a reserve,
  	 * or it might get too enthusiastic.
  	 */
  	return acm_wb_is_avail(acm) ? acm->writesize : 0;
  }
  
  static int acm_tty_chars_in_buffer(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  	/*
  	 * if the device was unplugged then any remaining characters fell out
  	 * of the connector ;)
  	 */
  	if (acm->disconnected)
  		return 0;
  	/*
  	 * This is inaccurate (overcounts), but it works.
  	 */
  	return (ACM_NW - acm_wb_is_avail(acm)) * acm->writesize;
  }
  
  static void acm_tty_throttle(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  
  	spin_lock_irq(&acm->read_lock);
  	acm->throttle_req = 1;
  	spin_unlock_irq(&acm->read_lock);
  }
  
  static void acm_tty_unthrottle(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  	unsigned int was_throttled;
  
  	spin_lock_irq(&acm->read_lock);
  	was_throttled = acm->throttled;
  	acm->throttled = 0;
  	acm->throttle_req = 0;
  	spin_unlock_irq(&acm->read_lock);
  
  	if (was_throttled)
  		acm_submit_read_urbs(acm, GFP_KERNEL);
  }
  
  static int acm_tty_break_ctl(struct tty_struct *tty, int state)
  {
  	struct acm *acm = tty->driver_data;
  	int retval;
  
  	retval = acm_send_break(acm, state ? 0xffff : 0);
  	if (retval < 0)
  		dev_dbg(&acm->control->dev, "%s - send break failed\n",
  								__func__);
  	return retval;
  }
  
  static int acm_tty_tiocmget(struct tty_struct *tty)
  {
  	struct acm *acm = tty->driver_data;
  
  	return (acm->ctrlout & ACM_CTRL_DTR ? TIOCM_DTR : 0) |
  	       (acm->ctrlout & ACM_CTRL_RTS ? TIOCM_RTS : 0) |
  	       (acm->ctrlin  & ACM_CTRL_DSR ? TIOCM_DSR : 0) |
  	       (acm->ctrlin  & ACM_CTRL_RI  ? TIOCM_RI  : 0) |
  	       (acm->ctrlin  & ACM_CTRL_DCD ? TIOCM_CD  : 0) |
  	       TIOCM_CTS;
  }
  
  static int acm_tty_tiocmset(struct tty_struct *tty,
  			    unsigned int set, unsigned int clear)
  {
  	struct acm *acm = tty->driver_data;
  	unsigned int newctrl;
  
  	newctrl = acm->ctrlout;
  	set = (set & TIOCM_DTR ? ACM_CTRL_DTR : 0) |
  					(set & TIOCM_RTS ? ACM_CTRL_RTS : 0);
  	clear = (clear & TIOCM_DTR ? ACM_CTRL_DTR : 0) |
  					(clear & TIOCM_RTS ? ACM_CTRL_RTS : 0);
  
  	newctrl = (newctrl & ~clear) | set;
  
  	if (acm->ctrlout == newctrl)
  		return 0;
  	return acm_set_control(acm, acm->ctrlout = newctrl);
  }
  
  static int get_serial_info(struct acm *acm, struct serial_struct __user *info)
  {
  	struct serial_struct tmp;
  
  	if (!info)
  		return -EINVAL;
  
  	memset(&tmp, 0, sizeof(tmp));
  	tmp.flags = ASYNC_LOW_LATENCY;
  	tmp.xmit_fifo_size = acm->writesize;
  	tmp.baud_base = le32_to_cpu(acm->line.dwDTERate);
  
  	if (copy_to_user(info, &tmp, sizeof(tmp)))
  		return -EFAULT;
  	else
  		return 0;
  }
  
  static int acm_tty_ioctl(struct tty_struct *tty,
  					unsigned int cmd, unsigned long arg)
  {
  	struct acm *acm = tty->driver_data;
  	int rv = -ENOIOCTLCMD;
  
  	switch (cmd) {
  	case TIOCGSERIAL: /* gets serial port data */
  		rv = get_serial_info(acm, (struct serial_struct __user *) arg);
  		break;
  	}
  
  	return rv;
  }
  
  static const __u32 acm_tty_speed[] = {
  	0, 50, 75, 110, 134, 150, 200, 300, 600,
  	1200, 1800, 2400, 4800, 9600, 19200, 38400,
  	57600, 115200, 230400, 460800, 500000, 576000,
  	921600, 1000000, 1152000, 1500000, 2000000,
  	2500000, 3000000, 3500000, 4000000
  };
  
  static const __u8 acm_tty_size[] = {
  	5, 6, 7, 8
  };
  
  static void acm_tty_set_termios(struct tty_struct *tty,
  						struct ktermios *termios_old)
  {
  	struct acm *acm = tty->driver_data;
  	struct ktermios *termios = tty->termios;
  	struct usb_cdc_line_coding newline;
  	int newctrl = acm->ctrlout;
  
  	newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
  	newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
  	newline.bParityType = termios->c_cflag & PARENB ?
  				(termios->c_cflag & PARODD ? 1 : 2) +
  				(termios->c_cflag & CMSPAR ? 2 : 0) : 0;
  	newline.bDataBits = acm_tty_size[(termios->c_cflag & CSIZE) >> 4];
  	/* FIXME: Needs to clear unsupported bits in the termios */
  	acm->clocal = ((termios->c_cflag & CLOCAL) != 0);
  
  	if (!newline.dwDTERate) {
  		newline.dwDTERate = acm->line.dwDTERate;
  		newctrl &= ~ACM_CTRL_DTR;
  	} else
  		newctrl |=  ACM_CTRL_DTR;
  
  	if (newctrl != acm->ctrlout)
  		acm_set_control(acm, acm->ctrlout = newctrl);
  
  	if (memcmp(&acm->line, &newline, sizeof newline)) {
  		memcpy(&acm->line, &newline, sizeof newline);
  		dev_dbg(&acm->control->dev, "%s - set line: %d %d %d %d\n",
  			__func__,
  			le32_to_cpu(newline.dwDTERate),
  			newline.bCharFormat, newline.bParityType,
  			newline.bDataBits);
  		acm_set_line(acm, &acm->line);
  	}
  }
  
  static const struct tty_port_operations acm_port_ops = {
  	.shutdown = acm_port_shutdown,
  	.activate = acm_port_activate,
  	.destruct = acm_port_destruct,
  };
  
  /*
   * USB probe and disconnect routines.
   */
  
  /* Little helpers: write/read buffers free */
  static void acm_write_buffers_free(struct acm *acm)
  {
  	int i;
  	struct acm_wb *wb;
  	struct usb_device *usb_dev = interface_to_usbdev(acm->control);
  
  	for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++)
  		usb_free_coherent(usb_dev, acm->writesize, wb->buf, wb->dmah);
  }
  
  static void acm_read_buffers_free(struct acm *acm)
  {
  	struct usb_device *usb_dev = interface_to_usbdev(acm->control);
  	int i;
  
  	for (i = 0; i < acm->rx_buflimit; i++)
  		usb_free_coherent(usb_dev, acm->readsize,
  			  acm->read_buffers[i].base, acm->read_buffers[i].dma);
  }
  
  /* Little helper: write buffers allocate */
  static int acm_write_buffers_alloc(struct acm *acm)
  {
  	int i;
  	struct acm_wb *wb;
  
  	for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++) {
  		wb->buf = usb_alloc_coherent(acm->dev, acm->writesize, GFP_KERNEL,
  		    &wb->dmah);
  		if (!wb->buf) {
  			while (i != 0) {
  				--i;
  				--wb;
  				usb_free_coherent(acm->dev, acm->writesize,
  				    wb->buf, wb->dmah);
  			}
  			return -ENOMEM;
  		}
  	}
  	return 0;
  }
  
  static int acm_probe(struct usb_interface *intf,
  		     const struct usb_device_id *id)
  {
  	struct usb_cdc_union_desc *union_header = NULL;
  	struct usb_cdc_country_functional_desc *cfd = NULL;
  	unsigned char *buffer = intf->altsetting->extra;
  	int buflen = intf->altsetting->extralen;
  	struct usb_interface *control_interface;
  	struct usb_interface *data_interface;
  	struct usb_endpoint_descriptor *epctrl = NULL;
  	struct usb_endpoint_descriptor *epread = NULL;
  	struct usb_endpoint_descriptor *epwrite = NULL;
  	struct usb_device *usb_dev = interface_to_usbdev(intf);
  	struct acm *acm;
  	int minor;
  	int ctrlsize, readsize;
  	u8 *buf;
  	u8 ac_management_function = 0;
  	u8 call_management_function = 0;
  	int call_interface_num = -1;
  	int data_interface_num = -1;
  	unsigned long quirks;
  	int num_rx_buf;
  	int i;
  	int combined_interfaces = 0;
  
  	/* normal quirks */
  	quirks = (unsigned long)id->driver_info;
  	num_rx_buf = (quirks == SINGLE_RX_URB) ? 1 : ACM_NR;
  
  	/* handle quirks deadly to normal probing*/
  	if (quirks == NO_UNION_NORMAL) {
  		data_interface = usb_ifnum_to_if(usb_dev, 1);
  		control_interface = usb_ifnum_to_if(usb_dev, 0);
  		/* we would crash */
  		if (!data_interface || !control_interface)
  			return -ENODEV;
  		goto skip_normal_probe;
  	}
  
  	/* normal probing*/
  	if (!buffer) {
  		dev_err(&intf->dev, "Weird descriptor references\n");
  		return -EINVAL;
  	}
  
  	if (!buflen) {
  		if (intf->cur_altsetting->endpoint &&
  				intf->cur_altsetting->endpoint->extralen &&
  				intf->cur_altsetting->endpoint->extra) {
  			dev_dbg(&intf->dev,
  				"Seeking extra descriptors on endpoint\n");
  			buflen = intf->cur_altsetting->endpoint->extralen;
  			buffer = intf->cur_altsetting->endpoint->extra;
  		} else {
  			dev_err(&intf->dev,
  				"Zero length descriptor references\n");
  			return -EINVAL;
  		}
  	}
  
  	while (buflen > 0) {
  		if (buffer[1] != USB_DT_CS_INTERFACE) {
  			dev_err(&intf->dev, "skipping garbage\n");
  			goto next_desc;
  		}
  
  		switch (buffer[2]) {
  		case USB_CDC_UNION_TYPE: /* we've found it */
  			if (union_header) {
  				dev_err(&intf->dev, "More than one "
  					"union descriptor, skipping ...\n");
  				goto next_desc;
  			}
  			union_header = (struct usb_cdc_union_desc *)buffer;
  			break;
  		case USB_CDC_COUNTRY_TYPE: /* export through sysfs*/
  			cfd = (struct usb_cdc_country_functional_desc *)buffer;
  			break;
  		case USB_CDC_HEADER_TYPE: /* maybe check version */
  			break; /* for now we ignore it */
  		case USB_CDC_ACM_TYPE:
  			ac_management_function = buffer[3];
  			break;
  		case USB_CDC_CALL_MANAGEMENT_TYPE:
  			call_management_function = buffer[3];
  			call_interface_num = buffer[4];
  			if ( (quirks & NOT_A_MODEM) == 0 && (call_management_function & 3) != 3)
  				dev_err(&intf->dev, "This device cannot do calls on its own. It is not a modem.\n");
  			break;
  		default:
  			/* there are LOTS more CDC descriptors that
  			 * could legitimately be found here.
  			 */
  			dev_dbg(&intf->dev, "Ignoring descriptor: "
  					"type %02x, length %d\n",
  					buffer[2], buffer[0]);
  			break;
  		}
  next_desc:
  		buflen -= buffer[0];
  		buffer += buffer[0];
  	}
  
  	if (!union_header) {
  		if (call_interface_num > 0) {
  			dev_dbg(&intf->dev, "No union descriptor, using call management descriptor\n");
  			/* quirks for Droids MuIn LCD */
  			if (quirks & NO_DATA_INTERFACE)
  				data_interface = usb_ifnum_to_if(usb_dev, 0);
  			else
  				data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num));
  			control_interface = intf;
  		} else {
  			if (intf->cur_altsetting->desc.bNumEndpoints != 3) {
  				dev_dbg(&intf->dev,"No union descriptor, giving up\n");
  				return -ENODEV;
  			} else {
  				dev_warn(&intf->dev,"No union descriptor, testing for castrated device\n");
  				combined_interfaces = 1;
  				control_interface = data_interface = intf;
  				goto look_for_collapsed_interface;
  			}
  		}
  	} else {
  		control_interface = usb_ifnum_to_if(usb_dev, union_header->bMasterInterface0);
  		data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = union_header->bSlaveInterface0));
  		if (!control_interface || !data_interface) {
  			dev_dbg(&intf->dev, "no interfaces\n");
  			return -ENODEV;
  		}
  	}
  
  	if (data_interface_num != call_interface_num)
  		dev_dbg(&intf->dev, "Separate call control interface. That is not fully supported.\n");
  
  	if (control_interface == data_interface) {
  		/* some broken devices designed for windows work this way */
  		dev_warn(&intf->dev,"Control and data interfaces are not separated!\n");
  		combined_interfaces = 1;
  		/* a popular other OS doesn't use it */
  		quirks |= NO_CAP_LINE;
  		if (data_interface->cur_altsetting->desc.bNumEndpoints != 3) {
  			dev_err(&intf->dev, "This needs exactly 3 endpoints\n");
  			return -EINVAL;
  		}
  look_for_collapsed_interface:
  		for (i = 0; i < 3; i++) {
  			struct usb_endpoint_descriptor *ep;
  			ep = &data_interface->cur_altsetting->endpoint[i].desc;
  
  			if (usb_endpoint_is_int_in(ep))
  				epctrl = ep;
  			else if (usb_endpoint_is_bulk_out(ep))
  				epwrite = ep;
  			else if (usb_endpoint_is_bulk_in(ep))
  				epread = ep;
  			else
  				return -EINVAL;
  		}
  		if (!epctrl || !epread || !epwrite)
  			return -ENODEV;
  		else
  			goto made_compressed_probe;
  	}
  
  skip_normal_probe:
  
  	/*workaround for switched interfaces */
  	if (data_interface->cur_altsetting->desc.bInterfaceClass
  						!= CDC_DATA_INTERFACE_TYPE) {
  		if (control_interface->cur_altsetting->desc.bInterfaceClass
  						== CDC_DATA_INTERFACE_TYPE) {
  			struct usb_interface *t;
  			dev_dbg(&intf->dev,
  				"Your device has switched interfaces.\n");
  			t = control_interface;
  			control_interface = data_interface;
  			data_interface = t;
  		} else {
  			return -EINVAL;
  		}
  	}
  
  	/* Accept probe requests only for the control interface */
  	if (!combined_interfaces && intf != control_interface)
  		return -ENODEV;
  
  	if (!combined_interfaces && usb_interface_claimed(data_interface)) {
  		/* valid in this context */
  		dev_dbg(&intf->dev, "The data interface isn't available\n");
  		return -EBUSY;
  	}
  
  
  	if (data_interface->cur_altsetting->desc.bNumEndpoints < 2)
  		return -EINVAL;
  
  	epctrl = &control_interface->cur_altsetting->endpoint[0].desc;
  	epread = &data_interface->cur_altsetting->endpoint[0].desc;
  	epwrite = &data_interface->cur_altsetting->endpoint[1].desc;
  
  
  	/* workaround for switched endpoints */
  	if (!usb_endpoint_dir_in(epread)) {
  		/* descriptors are swapped */
  		struct usb_endpoint_descriptor *t;
  		dev_dbg(&intf->dev,
  			"The data interface has switched endpoints\n");
  		t = epread;
  		epread = epwrite;
  		epwrite = t;
  	}
  made_compressed_probe:
  	dev_dbg(&intf->dev, "interfaces are valid\n");
  
  	acm = kzalloc(sizeof(struct acm), GFP_KERNEL);
  	if (acm == NULL) {
  		dev_err(&intf->dev, "out of memory (acm kzalloc)\n");
  		goto alloc_fail;
  	}
  
  	minor = acm_alloc_minor(acm);
  	if (minor == ACM_TTY_MINORS) {
  		dev_err(&intf->dev, "no more free acm devices\n");
  		kfree(acm);
  		return -ENODEV;
  	}
  
  	ctrlsize = usb_endpoint_maxp(epctrl);
  	readsize = usb_endpoint_maxp(epread) *
  				(quirks == SINGLE_RX_URB ? 1 : 2);
  	acm->combined_interfaces = combined_interfaces;
  	acm->writesize = usb_endpoint_maxp(epwrite) * 20;
  	acm->control = control_interface;
  	acm->data = data_interface;
  	acm->minor = minor;
  	acm->dev = usb_dev;
  	acm->ctrl_caps = ac_management_function;
  	if (quirks & NO_CAP_LINE)
  		acm->ctrl_caps &= ~USB_CDC_CAP_LINE;
  	acm->ctrlsize = ctrlsize;
  	acm->readsize = readsize;
  	acm->rx_buflimit = num_rx_buf;
  	INIT_WORK(&acm->work, acm_softint);
  	spin_lock_init(&acm->write_lock);
  	spin_lock_init(&acm->read_lock);
  	mutex_init(&acm->mutex);
  	acm->rx_endpoint = usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress);
  	acm->is_int_ep = usb_endpoint_xfer_int(epread);
  	if (acm->is_int_ep)
  		acm->bInterval = epread->bInterval;
  	tty_port_init(&acm->port);
  	acm->port.ops = &acm_port_ops;
  
  	buf = usb_alloc_coherent(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
  	if (!buf) {
  		dev_err(&intf->dev, "out of memory (ctrl buffer alloc)\n");
  		goto alloc_fail2;
  	}
  	acm->ctrl_buffer = buf;
  
  	if (acm_write_buffers_alloc(acm) < 0) {
  		dev_err(&intf->dev, "out of memory (write buffer alloc)\n");
  		goto alloc_fail4;
  	}
  
  	acm->ctrlurb = usb_alloc_urb(0, GFP_KERNEL);
  	if (!acm->ctrlurb) {
  		dev_err(&intf->dev, "out of memory (ctrlurb kmalloc)\n");
  		goto alloc_fail5;
  	}
  	for (i = 0; i < num_rx_buf; i++) {
  		struct acm_rb *rb = &(acm->read_buffers[i]);
  		struct urb *urb;
  
  		rb->base = usb_alloc_coherent(acm->dev, readsize, GFP_KERNEL,
  								&rb->dma);
  		if (!rb->base) {
  			dev_err(&intf->dev, "out of memory "
  					"(read bufs usb_alloc_coherent)\n");
  			goto alloc_fail6;
  		}
  		rb->index = i;
  		rb->instance = acm;
  
  		urb = usb_alloc_urb(0, GFP_KERNEL);
  		if (!urb) {
  			dev_err(&intf->dev,
  				"out of memory (read urbs usb_alloc_urb)\n");
  			goto alloc_fail6;
  		}
  		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
  		urb->transfer_dma = rb->dma;
  		if (acm->is_int_ep) {
  			usb_fill_int_urb(urb, acm->dev,
  					 acm->rx_endpoint,
  					 rb->base,
  					 acm->readsize,
  					 acm_read_bulk_callback, rb,
  					 acm->bInterval);
  		} else {
  			usb_fill_bulk_urb(urb, acm->dev,
  					  acm->rx_endpoint,
  					  rb->base,
  					  acm->readsize,
  					  acm_read_bulk_callback, rb);
  		}
  
  		acm->read_urbs[i] = urb;
  		__set_bit(i, &acm->read_urbs_free);
  	}
  	for (i = 0; i < ACM_NW; i++) {
  		struct acm_wb *snd = &(acm->wb[i]);
  
  		snd->urb = usb_alloc_urb(0, GFP_KERNEL);
  		if (snd->urb == NULL) {
  			dev_err(&intf->dev,
  				"out of memory (write urbs usb_alloc_urb)\n");
  			goto alloc_fail7;
  		}
  
  		if (usb_endpoint_xfer_int(epwrite))
  			usb_fill_int_urb(snd->urb, usb_dev,
  				usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
  				NULL, acm->writesize, acm_write_bulk, snd, epwrite->bInterval);
  		else
  			usb_fill_bulk_urb(snd->urb, usb_dev,
  				usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
  				NULL, acm->writesize, acm_write_bulk, snd);
  		snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
  		snd->instance = acm;
  	}
  
  	usb_set_intfdata(intf, acm);
  
  	i = device_create_file(&intf->dev, &dev_attr_bmCapabilities);
  	if (i < 0)
  		goto alloc_fail7;
  
  	if (cfd) { /* export the country data */
  		acm->country_codes = kmalloc(cfd->bLength - 4, GFP_KERNEL);
  		if (!acm->country_codes)
  			goto skip_countries;
  		acm->country_code_size = cfd->bLength - 4;
  		memcpy(acm->country_codes, (u8 *)&cfd->wCountyCode0,
  							cfd->bLength - 4);
  		acm->country_rel_date = cfd->iCountryCodeRelDate;
  
  		i = device_create_file(&intf->dev, &dev_attr_wCountryCodes);
  		if (i < 0) {
  			kfree(acm->country_codes);
  			acm->country_codes = NULL;
  			acm->country_code_size = 0;
  			goto skip_countries;
  		}
  
  		i = device_create_file(&intf->dev,
  						&dev_attr_iCountryCodeRelDate);
  		if (i < 0) {
  			device_remove_file(&intf->dev, &dev_attr_wCountryCodes);
  			kfree(acm->country_codes);
  			acm->country_codes = NULL;
  			acm->country_code_size = 0;
  			goto skip_countries;
  		}
  	}
  
  skip_countries:
  	usb_fill_int_urb(acm->ctrlurb, usb_dev,
  			 usb_rcvintpipe(usb_dev, epctrl->bEndpointAddress),
  			 acm->ctrl_buffer, ctrlsize, acm_ctrl_irq, acm,
  			 /* works around buggy devices */
  			 epctrl->bInterval ? epctrl->bInterval : 0xff);
  	acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
  	acm->ctrlurb->transfer_dma = acm->ctrl_dma;
  
  	dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
  
  	acm_set_control(acm, acm->ctrlout);
  
  	acm->line.dwDTERate = cpu_to_le32(9600);
  	acm->line.bDataBits = 8;
  	acm_set_line(acm, &acm->line);
  
  	usb_driver_claim_interface(&acm_driver, data_interface, acm);
  	usb_set_intfdata(data_interface, acm);
  
  	usb_get_intf(control_interface);
  	tty_register_device(acm_tty_driver, minor, &control_interface->dev);
  
  	return 0;
  alloc_fail7:
  	for (i = 0; i < ACM_NW; i++)
  		usb_free_urb(acm->wb[i].urb);
  alloc_fail6:
  	for (i = 0; i < num_rx_buf; i++)
  		usb_free_urb(acm->read_urbs[i]);
  	acm_read_buffers_free(acm);
  	usb_free_urb(acm->ctrlurb);
  alloc_fail5:
  	acm_write_buffers_free(acm);
  alloc_fail4:
  	usb_free_coherent(usb_dev, ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
  alloc_fail2:
  	acm_release_minor(acm);
  	kfree(acm);
  alloc_fail:
  	return -ENOMEM;
  }
  
  static void stop_data_traffic(struct acm *acm)
  {
  	int i;
  
  	dev_dbg(&acm->control->dev, "%s\n", __func__);
  
  	usb_kill_urb(acm->ctrlurb);
  	for (i = 0; i < ACM_NW; i++)
  		usb_kill_urb(acm->wb[i].urb);
  	for (i = 0; i < acm->rx_buflimit; i++)
  		usb_kill_urb(acm->read_urbs[i]);
  
  	cancel_work_sync(&acm->work);
  }
  
  static void acm_disconnect(struct usb_interface *intf)
  {
  	struct acm *acm = usb_get_intfdata(intf);
  	struct usb_device *usb_dev = interface_to_usbdev(intf);
  	struct tty_struct *tty;
  	int i;
  
  	dev_dbg(&intf->dev, "%s\n", __func__);
  
  	/* sibling interface is already cleaning up */
  	if (!acm)
  		return;
  
  	mutex_lock(&acm->mutex);
  	acm->disconnected = true;
  	if (acm->country_codes) {
  		device_remove_file(&acm->control->dev,
  				&dev_attr_wCountryCodes);
  		device_remove_file(&acm->control->dev,
  				&dev_attr_iCountryCodeRelDate);
  	}
  	device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
  	usb_set_intfdata(acm->control, NULL);
  	usb_set_intfdata(acm->data, NULL);
  	mutex_unlock(&acm->mutex);
  
  	tty = tty_port_tty_get(&acm->port);
  	if (tty) {
  		tty_vhangup(tty);
  		tty_kref_put(tty);
  	}
  
  	stop_data_traffic(acm);
  
  	usb_free_urb(acm->ctrlurb);
  	for (i = 0; i < ACM_NW; i++)
  		usb_free_urb(acm->wb[i].urb);
  	for (i = 0; i < acm->rx_buflimit; i++)
  		usb_free_urb(acm->read_urbs[i]);
  	acm_write_buffers_free(acm);
  	usb_free_coherent(usb_dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
  	acm_read_buffers_free(acm);
  
  	if (!acm->combined_interfaces)
  		usb_driver_release_interface(&acm_driver, intf == acm->control ?
  					acm->data : acm->control);
  
  	tty_port_put(&acm->port);
  }
  
  #ifdef CONFIG_PM
  static int acm_suspend(struct usb_interface *intf, pm_message_t message)
  {
  	struct acm *acm = usb_get_intfdata(intf);
  	int cnt;
  
  	if (PMSG_IS_AUTO(message)) {
  		int b;
  
  		spin_lock_irq(&acm->write_lock);
  		b = acm->transmitting;
  		spin_unlock_irq(&acm->write_lock);
  		if (b)
  			return -EBUSY;
  	}
  
  	spin_lock_irq(&acm->read_lock);
  	spin_lock(&acm->write_lock);
  	cnt = acm->susp_count++;
  	spin_unlock(&acm->write_lock);
  	spin_unlock_irq(&acm->read_lock);
  
  	if (cnt)
  		return 0;
  
  	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags))
  		stop_data_traffic(acm);
  
  	return 0;
  }
  
  static int acm_resume(struct usb_interface *intf)
  {
  	struct acm *acm = usb_get_intfdata(intf);
  	struct acm_wb *wb;
  	int rv = 0;
  	int cnt;
  
  	spin_lock_irq(&acm->read_lock);
  	acm->susp_count -= 1;
  	cnt = acm->susp_count;
  	spin_unlock_irq(&acm->read_lock);
  
  	if (cnt)
  		return 0;
  
  	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) {
  		rv = usb_submit_urb(acm->ctrlurb, GFP_NOIO);
  
  		spin_lock_irq(&acm->write_lock);
  		if (acm->delayed_wb) {
  			wb = acm->delayed_wb;
  			acm->delayed_wb = NULL;
  			spin_unlock_irq(&acm->write_lock);
  			acm_start_wb(acm, wb);
  		} else {
  			spin_unlock_irq(&acm->write_lock);
  		}
  
  		/*
  		 * delayed error checking because we must
  		 * do the write path at all cost
  		 */
  		if (rv < 0)
  			goto err_out;
  
  		rv = acm_submit_read_urbs(acm, GFP_NOIO);
  	}
  
  err_out:
  	return rv;
  }
  
  static int acm_reset_resume(struct usb_interface *intf)
  {
  	struct acm *acm = usb_get_intfdata(intf);
  	struct tty_struct *tty;
  
  	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) {
  		tty = tty_port_tty_get(&acm->port);
  		if (tty) {
  			tty_hangup(tty);
  			tty_kref_put(tty);
  		}
  	}
  
  	return acm_resume(intf);
  }
  
  #endif /* CONFIG_PM */
  
  #define NOKIA_PCSUITE_ACM_INFO(x) \
  		USB_DEVICE_AND_INTERFACE_INFO(0x0421, x, \
  		USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \
  		USB_CDC_ACM_PROTO_VENDOR)
  
  #define SAMSUNG_PCSUITE_ACM_INFO(x) \
  		USB_DEVICE_AND_INTERFACE_INFO(0x04e7, x, \
  		USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM, \
  		USB_CDC_ACM_PROTO_VENDOR)
  
  /*
   * USB driver structure.
   */
  
  static const struct usb_device_id acm_ids[] = {
  	/* quirky and broken devices */
  	{ USB_DEVICE(0x0870, 0x0001), /* Metricom GS Modem */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0482, 0x0203), /* KYOCERA AH-K3001V */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x079b, 0x000f), /* BT On-Air USB MODEM */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0ace, 0x1602), /* ZyDAS 56K USB MODEM */
  	.driver_info = SINGLE_RX_URB,
  	},
  	{ USB_DEVICE(0x0ace, 0x1608), /* ZyDAS 56K USB MODEM */
  	.driver_info = SINGLE_RX_URB, /* firmware bug */
  	},
  	{ USB_DEVICE(0x0ace, 0x1611), /* ZyDAS 56K USB MODEM - new version */
  	.driver_info = SINGLE_RX_URB, /* firmware bug */
  	},
  	{ USB_DEVICE(0x22b8, 0x7000), /* Motorola Q Phone */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0803, 0x3095), /* Zoom Telephonics Model 3095F USB MODEM */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0572, 0x1321), /* Conexant USB MODEM CX93010 */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0572, 0x1324), /* Conexant USB MODEM RD02-D400 */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x0572, 0x1328), /* Shiro / Aztech USB MODEM UM-3100 */
  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
  	},
  	{ USB_DEVICE(0x22b8, 0x6425), /* Motorola MOTOMAGX phones */
  	},
  	/* Motorola H24 HSPA module: */
  	{ USB_DEVICE(0x22b8, 0x2d91) }, /* modem                                */
  	{ USB_DEVICE(0x22b8, 0x2d92) }, /* modem           + diagnostics        */
  	{ USB_DEVICE(0x22b8, 0x2d93) }, /* modem + AT port                      */
  	{ USB_DEVICE(0x22b8, 0x2d95) }, /* modem + AT port + diagnostics        */
  	{ USB_DEVICE(0x22b8, 0x2d96) }, /* modem                         + NMEA */
  	{ USB_DEVICE(0x22b8, 0x2d97) }, /* modem           + diagnostics + NMEA */
  	{ USB_DEVICE(0x22b8, 0x2d99) }, /* modem + AT port               + NMEA */
  	{ USB_DEVICE(0x22b8, 0x2d9a) }, /* modem + AT port + diagnostics + NMEA */
  
  	{ USB_DEVICE(0x0572, 0x1329), /* Hummingbird huc56s (Conexant) */
  	.driver_info = NO_UNION_NORMAL, /* union descriptor misplaced on
  					   data interface instead of
  					   communications interface.
  					   Maybe we should define a new
  					   quirk for this. */
  	},
  	{ USB_DEVICE(0x1bbb, 0x0003), /* Alcatel OT-I650 */
  	.driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
  	},
  	{ USB_DEVICE(0x1576, 0x03b1), /* Maretron USB100 */
  	.driver_info = NO_UNION_NORMAL, /* reports zero length descriptor */
  	},
  
  	/* Nokia S60 phones expose two ACM channels. The first is
  	 * a modem and is picked up by the standard AT-command
  	 * information below. The second is 'vendor-specific' but
  	 * is treated as a serial device at the S60 end, so we want
  	 * to expose it on Linux too. */
  	{ NOKIA_PCSUITE_ACM_INFO(0x042D), }, /* Nokia 3250 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04D8), }, /* Nokia 5500 Sport */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04C9), }, /* Nokia E50 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0419), }, /* Nokia E60 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x044D), }, /* Nokia E61 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0001), }, /* Nokia E61i */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0475), }, /* Nokia E62 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0508), }, /* Nokia E65 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0418), }, /* Nokia E70 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0425), }, /* Nokia N71 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0486), }, /* Nokia N73 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04DF), }, /* Nokia N75 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x000e), }, /* Nokia N77 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0445), }, /* Nokia N80 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x042F), }, /* Nokia N91 & N91 8GB */
  	{ NOKIA_PCSUITE_ACM_INFO(0x048E), }, /* Nokia N92 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0420), }, /* Nokia N93 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04E6), }, /* Nokia N93i  */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04B2), }, /* Nokia 5700 XpressMusic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0134), }, /* Nokia 6110 Navigator (China) */
  	{ NOKIA_PCSUITE_ACM_INFO(0x046E), }, /* Nokia 6110 Navigator */
  	{ NOKIA_PCSUITE_ACM_INFO(0x002f), }, /* Nokia 6120 classic &  */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0088), }, /* Nokia 6121 classic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x00fc), }, /* Nokia 6124 classic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0042), }, /* Nokia E51 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x00b0), }, /* Nokia E66 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x00ab), }, /* Nokia E71 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0481), }, /* Nokia N76 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0007), }, /* Nokia N81 & N81 8GB */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0071), }, /* Nokia N82 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04F0), }, /* Nokia N95 & N95-3 NAM */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0070), }, /* Nokia N95 8GB  */
  	{ NOKIA_PCSUITE_ACM_INFO(0x00e9), }, /* Nokia 5320 XpressMusic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0099), }, /* Nokia 6210 Navigator, RM-367 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0128), }, /* Nokia 6210 Navigator, RM-419 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x008f), }, /* Nokia 6220 Classic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x00a0), }, /* Nokia 6650 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x007b), }, /* Nokia N78 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0094), }, /* Nokia N85 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x003a), }, /* Nokia N96 & N96-3  */
  	{ NOKIA_PCSUITE_ACM_INFO(0x00e9), }, /* Nokia 5320 XpressMusic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0108), }, /* Nokia 5320 XpressMusic 2G */
  	{ NOKIA_PCSUITE_ACM_INFO(0x01f5), }, /* Nokia N97, RM-505 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x02e3), }, /* Nokia 5230, RM-588 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0178), }, /* Nokia E63 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x010e), }, /* Nokia E75 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x02d9), }, /* Nokia 6760 Slide */
  	{ NOKIA_PCSUITE_ACM_INFO(0x01d0), }, /* Nokia E52 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0223), }, /* Nokia E72 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0275), }, /* Nokia X6 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x026c), }, /* Nokia N97 Mini */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0154), }, /* Nokia 5800 XpressMusic */
  	{ NOKIA_PCSUITE_ACM_INFO(0x04ce), }, /* Nokia E90 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x01d4), }, /* Nokia E55 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0302), }, /* Nokia N8 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x0335), }, /* Nokia E7 */
  	{ NOKIA_PCSUITE_ACM_INFO(0x03cd), }, /* Nokia C7 */
  	{ SAMSUNG_PCSUITE_ACM_INFO(0x6651), }, /* Samsung GTi8510 (INNOV8) */
  
  	/* Support for Owen devices */
  	{ USB_DEVICE(0x03eb, 0x0030), }, /* Owen SI30 */
  
  	/* NOTE: non-Nokia COMM/ACM/0xff is likely MSFT RNDIS... NOT a modem! */
  
  	/* Support Lego NXT using pbLua firmware */
  	{ USB_DEVICE(0x0694, 0xff00),
  	.driver_info = NOT_A_MODEM,
  	},
  
  	/* Support for Droids MuIn LCD */
  	{ USB_DEVICE(0x04d8, 0x000b),
  	.driver_info = NO_DATA_INTERFACE,
  	},
  
  	/* control interfaces without any protocol set */
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_PROTO_NONE) },
  
  	/* control interfaces with various AT-command sets */
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_ACM_PROTO_AT_V25TER) },
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_ACM_PROTO_AT_PCCA101) },
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_ACM_PROTO_AT_PCCA101_WAKE) },
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_ACM_PROTO_AT_GSM) },
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_ACM_PROTO_AT_3G) },
  	{ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_ACM,
  		USB_CDC_ACM_PROTO_AT_CDMA) },
  
  	{ }
  };
  
  MODULE_DEVICE_TABLE(usb, acm_ids);
  
  static struct usb_driver acm_driver = {
  	.name =		"cdc_acm",
  	.probe =	acm_probe,
  	.disconnect =	acm_disconnect,
  #ifdef CONFIG_PM
  	.suspend =	acm_suspend,
  	.resume =	acm_resume,
  	.reset_resume =	acm_reset_resume,
  #endif
  	.id_table =	acm_ids,
  #ifdef CONFIG_PM
  	.supports_autosuspend = 1,
  #endif
  };
  
  /*
   * TTY driver structures.
   */
  
  static const struct tty_operations acm_ops = {
  	.install =		acm_tty_install,
  	.open =			acm_tty_open,
  	.close =		acm_tty_close,
  	.cleanup =		acm_tty_cleanup,
  	.hangup =		acm_tty_hangup,
  	.write =		acm_tty_write,
  	.write_room =		acm_tty_write_room,
  	.ioctl =		acm_tty_ioctl,
  	.throttle =		acm_tty_throttle,
  	.unthrottle =		acm_tty_unthrottle,
  	.chars_in_buffer =	acm_tty_chars_in_buffer,
  	.break_ctl =		acm_tty_break_ctl,
  	.set_termios =		acm_tty_set_termios,
  	.tiocmget =		acm_tty_tiocmget,
  	.tiocmset =		acm_tty_tiocmset,
  };
  
  /*
   * Init / exit.
   */
  
  static int __init acm_init(void)
  {
  	int retval;
  	acm_tty_driver = alloc_tty_driver(ACM_TTY_MINORS);
  	if (!acm_tty_driver)
  		return -ENOMEM;
  	acm_tty_driver->driver_name = "acm",
  	acm_tty_driver->name = "ttyACM",
  	acm_tty_driver->major = ACM_TTY_MAJOR,
  	acm_tty_driver->minor_start = 0,
  	acm_tty_driver->type = TTY_DRIVER_TYPE_SERIAL,
  	acm_tty_driver->subtype = SERIAL_TYPE_NORMAL,
  	acm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
  	acm_tty_driver->init_termios = tty_std_termios;
  	acm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD |
  								HUPCL | CLOCAL;
  	tty_set_operations(acm_tty_driver, &acm_ops);
  
  	retval = tty_register_driver(acm_tty_driver);
  	if (retval) {
  		put_tty_driver(acm_tty_driver);
  		return retval;
  	}
  
  	retval = usb_register(&acm_driver);
  	if (retval) {
  		tty_unregister_driver(acm_tty_driver);
  		put_tty_driver(acm_tty_driver);
  		return retval;
  	}
  
  	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");
  
  	return 0;
  }
  
  static void __exit acm_exit(void)
  {
  	usb_deregister(&acm_driver);
  	tty_unregister_driver(acm_tty_driver);
  	put_tty_driver(acm_tty_driver);
  }
  
  module_init(acm_init);
  module_exit(acm_exit);
  
  MODULE_AUTHOR(DRIVER_AUTHOR);
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_CHARDEV_MAJOR(ACM_TTY_MAJOR);
  