text: /*
   * USB Network driver infrastructure
   * Copyright (C) 2000-2005 by David Brownell
   * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
   *
   * 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
   */
  
  /*
   * This is a generic "USB networking" framework that works with several
   * kinds of full and high speed networking devices:  host-to-host cables,
   * smart usb peripherals, and actual Ethernet adapters.
   *
   * These devices usually differ in terms of control protocols (if they
   * even have one!) and sometimes they define new framing to wrap or batch
   * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
   * so interface (un)binding, endpoint I/O queues, fault handling, and other
   * issues can usefully be addressed by this framework.
   */
  
  // #define	DEBUG			// error path messages, extra info
  // #define	VERBOSE			// more; success messages
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/ctype.h>
  #include <linux/ethtool.h>
  #include <linux/workqueue.h>
  #include <linux/mii.h>
  #include <linux/usb.h>
  #include <linux/usb/usbnet.h>
  #include <linux/slab.h>
  #include <linux/kernel.h>
  #include <linux/pm_runtime.h>
  
  #define DRIVER_VERSION		"22-Aug-2005"
  
  
  /*-------------------------------------------------------------------------*/
  
  /*
   * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
   * Several dozen bytes of IPv4 data can fit in two such transactions.
   * One maximum size Ethernet packet takes twenty four of them.
   * For high speed, each frame comfortably fits almost 36 max size
   * Ethernet packets (so queues should be bigger).
   *
   * REVISIT qlens should be members of 'struct usbnet'; the goal is to
   * let the USB host controller be busy for 5msec or more before an irq
   * is required, under load.  Jumbograms change the equation.
   */
  
  /* K3 optimized for LTE ->*/
  /* Zero-copy seems good, but it can waste a lot of memory if the upper-layers
  can not free skbs in time, it likely to cause low-memory issue when downloading
  in a high speed. So we use a fixed number of Rx buffer, and will copy data to
  small skbs in rx process */
  #define NUM_OF_RX_BUF            10
  /* <- K3 optimized for LTE*/
  
   /*
  #define RX_MAX_QUEUE_MEMORY (60 * 1518)
  #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
              (RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
  #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
              (RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)
  */
  #define RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? NUM_OF_RX_BUF : 4)
  #define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? 10 : 4)
  
  
  // reawaken network queue this soon after stopping; else watchdog barks
  #define TX_TIMEOUT_JIFFIES	(5*HZ)
  
  // throttle rx/tx briefly after some faults, so khubd might disconnect()
  // us (it polls at HZ/4 usually) before we report too many false errors.
  #define THROTTLE_JIFFIES	(HZ/8)
  
  /* a temporary debug infomation */
  #define K3_DBG_LOG  pr_info
  
  static DEFINE_MUTEX(sr_mutex);
  
  // between wakeups
  #define UNLINK_TIMEOUT_MS	3
  
  #define USBNET_NET_MINORS	3
  /*-------------------------------------------------------------------------*/
  
  // randomly generated ethernet address
  static u8	node_id [ETH_ALEN];
  
  static const char driver_name [] = "usbnet";
  
  /* store usbnet for SR */
  static struct usbnet *usbnet_table[USBNET_NET_MINORS];
  
  /* use ethtool to change the level for any given device */
  static int msg_level = -1;
  module_param (msg_level, int, 0);
  MODULE_PARM_DESC (msg_level, "Override default message level");
  
  /*-------------------------------------------------------------------------*/
  
  /* handles CDC Ethernet and many other network "bulk data" interfaces */
  int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
  {
  	int				tmp;
  	struct usb_host_interface	*alt = NULL;
  	struct usb_host_endpoint	*in = NULL, *out = NULL;
  	struct usb_host_endpoint	*status = NULL;
  
  	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
  		unsigned	ep;
  
  		in = out = status = NULL;
  		alt = intf->altsetting + tmp;
  
  		/* take the first altsetting with in-bulk + out-bulk;
  		 * remember any status endpoint, just in case;
  		 * ignore other endpoints and altsettings.
  		 */
  		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
  			struct usb_host_endpoint	*e;
  			int				intr = 0;
  
  			e = alt->endpoint + ep;
  			switch (e->desc.bmAttributes) {
  			case USB_ENDPOINT_XFER_INT:
  				if (!usb_endpoint_dir_in(&e->desc))
  					continue;
  				intr = 1;
  				/* FALLTHROUGH */
  			case USB_ENDPOINT_XFER_BULK:
  				break;
  			default:
  				continue;
  			}
  			if (usb_endpoint_dir_in(&e->desc)) {
  				if (!intr && !in)
  					in = e;
  				else if (intr && !status)
  					status = e;
  			} else {
  				if (!out)
  					out = e;
  			}
  		}
  		if (in && out)
  			break;
  	}
  	if (!alt || !in || !out)
  		return -EINVAL;
  
  	if (alt->desc.bAlternateSetting != 0 ||
  	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
  		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
  				alt->desc.bAlternateSetting);
  		if (tmp < 0)
  			return tmp;
  	}
  
  	dev->in = usb_rcvbulkpipe (dev->udev,
  			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
  	dev->out = usb_sndbulkpipe (dev->udev,
  			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
  	dev->status = status;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
  
  int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
  {
  	int 		tmp, i;
  	unsigned char	buf [13];
  
  	tmp = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
  	if (tmp != 12) {
  		dev_dbg(&dev->udev->dev,
  			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
  		if (tmp >= 0)
  			tmp = -EINVAL;
  		return tmp;
  	}
  	for (i = tmp = 0; i < 6; i++, tmp += 2)
  		dev->net->dev_addr [i] =
  			(hex_to_bin(buf[tmp]) << 4) + hex_to_bin(buf[tmp + 1]);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
  
  static void intr_complete (struct urb *urb);
  
  static int init_status (struct usbnet *dev, struct usb_interface *intf)
  {
  	char		*buf = NULL;
  	unsigned	pipe = 0;
  	unsigned	maxp;
  	unsigned	period;
  
  	if (!dev->driver_info->status)
  		return 0;
  
  	pipe = usb_rcvintpipe (dev->udev,
  			dev->status->desc.bEndpointAddress
  				& USB_ENDPOINT_NUMBER_MASK);
  	maxp = usb_maxpacket (dev->udev, pipe, 0);
  
  	/* avoid 1 msec chatter:  min 8 msec poll rate */
  	period = max ((int) dev->status->desc.bInterval,
  		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
  
  	buf = kmalloc (maxp, GFP_KERNEL);
  	if (buf) {
  		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
  		if (!dev->interrupt) {
  			kfree (buf);
  			return -ENOMEM;
  		} else {
  			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
  				buf, maxp, intr_complete, dev, period);
  			dev_dbg(&intf->dev,
  				"status ep%din, %d bytes period %d\n",
  				usb_pipeendpoint(pipe), maxp, period);
  		}
  	}
  	return 0;
  }
  
  /* Passes this packet up the stack, updating its accounting.
   * Some link protocols batch packets, so their rx_fixup paths
   * can return clones as well as just modify the original skb.
   */
  void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
  {
  	int	status;
  
  	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
  		skb_queue_tail(&dev->rxq_pause, skb);
  		return;
  	}
  
  	skb->protocol = eth_type_trans (skb, dev->net);
  	dev->net->stats.rx_packets++;
  	dev->net->stats.rx_bytes += skb->len;
  
  	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
  		  skb->len + sizeof (struct ethhdr), skb->protocol);
  	memset (skb->cb, 0, sizeof (struct skb_data));
  	status = netif_rx (skb);
  	if (status != NET_RX_SUCCESS)
  		netif_dbg(dev, rx_err, dev->net,
  			  "netif_rx status %d\n", status);
  }
  EXPORT_SYMBOL_GPL(usbnet_skb_return);
  
  
  /*-------------------------------------------------------------------------
   *
   * Network Device Driver (peer link to "Host Device", from USB host)
   *
   *-------------------------------------------------------------------------*/
  
  int usbnet_change_mtu (struct net_device *net, int new_mtu)
  {
  	struct usbnet	*dev = netdev_priv(net);
  	int		ll_mtu = new_mtu + net->hard_header_len;
  	int		old_hard_mtu = dev->hard_mtu;
  	int		old_rx_urb_size = dev->rx_urb_size;
  
  	if (new_mtu <= 0)
  		return -EINVAL;
  	// no second zero-length packet read wanted after mtu-sized packets
  	if ((ll_mtu % dev->maxpacket) == 0)
  		return -EDOM;
  	net->mtu = new_mtu;
  
  	dev->hard_mtu = net->mtu + net->hard_header_len;
  	if (dev->rx_urb_size == old_hard_mtu) {
  		dev->rx_urb_size = dev->hard_mtu;
  		if (dev->rx_urb_size > old_rx_urb_size)
  			usbnet_unlink_rx_urbs(dev);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usbnet_change_mtu);
  
  /*-------------------------------------------------------------------------*/
  
  /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
   * completion callbacks.  2.5 should have fixed those bugs...
   */
  
  static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
  {
  	unsigned long		flags;
  
  	spin_lock_irqsave(&list->lock, flags);
  	__skb_unlink(skb, list);
  	spin_unlock(&list->lock);
  	spin_lock(&dev->done.lock);
  	__skb_queue_tail(&dev->done, skb);
  	if (dev->done.qlen == 1)
  		tasklet_schedule(&dev->bh);
  	spin_unlock_irqrestore(&dev->done.lock, flags);
  }
  
  /* some work can't be done in tasklets, so we use keventd
   *
   * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
   * but tasklet_schedule() doesn't.  hope the failure is rare.
   */
  void usbnet_defer_kevent (struct usbnet *dev, int work)
  {
  	set_bit (work, &dev->flags);
  	if (!schedule_work (&dev->kevent))
  		netdev_err(dev->net, "kevent %d may have been dropped\n", work);
  	else
  		netdev_err(dev->net, "kevent %d scheduled\n", work);
  }
  EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
  
  /*-------------------------------------------------------------------------*/
  
  static void rx_complete (struct urb *urb);
  
  static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
  {
  	struct sk_buff		*skb;
  	struct skb_data		*entry;
  	int			retval = 0;
  	unsigned long		lockflags;
  	size_t			size = dev->rx_urb_size;
  
  	/* K3 optimized for LTE -> */
  /*
  	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
  		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
  		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
  		usb_free_urb (urb);
  		return -ENOMEM;
  	}
  	skb_reserve (skb, NET_IP_ALIGN);
  */
  	skb = skb_dequeue(&dev->freeq);
  	/* rx_submit will be called only when freeq is not empty */
  	BUG_ON(skb == NULL);
  	skb_reset_tail_pointer(skb);
  	skb->len = 0;
  	/* <- K3 optimized for LTE */
  
  	entry = (struct skb_data *) skb->cb;
  	entry->urb = urb;
  	entry->dev = dev;
  	entry->state = rx_start;
  	entry->length = 0;
  
  	usb_fill_bulk_urb (urb, dev->udev, dev->in,
  		skb->data, size, rx_complete, skb);
  
  	spin_lock_irqsave (&dev->rxq.lock, lockflags);
  
  	if (netif_running (dev->net) &&
  	    netif_device_present (dev->net) &&
  	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
  	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
  		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
  		case -EPIPE:
  			usbnet_defer_kevent (dev, EVENT_RX_HALT);
  			break;
  		case -ENOMEM:
  			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
  			break;
  		case -ENODEV:
  			netif_dbg(dev, ifdown, dev->net, "device gone\n");
  			netif_device_detach (dev->net);
  			break;
  		case -EHOSTUNREACH:
  			retval = -ENOLINK;
  			break;
  		default:
  			netif_dbg(dev, rx_err, dev->net,
  				  "rx submit, %d\n", retval);
  			tasklet_schedule (&dev->bh);
  			break;
  		case 0:
  			__skb_queue_tail (&dev->rxq, skb);
  		}
  	} else {
  		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
  		retval = -ENOLINK;
  	}
  	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
  	if (retval) {
  		/* K3 optimized for LTE -> */
  		//dev_kfree_skb_any (skb);
  		skb_queue_tail(&dev->freeq, skb);
  		/* <- K3 optimized for LTE */
  		usb_free_urb (urb);
  	}
  	return retval;
  }
  
  
  /*-------------------------------------------------------------------------*/
  
  static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
  {
  	if (dev->driver_info->rx_fixup &&
  	    !dev->driver_info->rx_fixup (dev, skb)) {
  		/* With RX_ASSEMBLE, rx_fixup() must update counters */
  		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
  			dev->net->stats.rx_errors++;
  		goto done;
  	}
  	// else network stack removes extra byte if we forced a short packet
  
  	if (skb->len) {
  		/* all data was already cloned from skb inside the driver */
  		if (dev->driver_info->flags & FLAG_MULTI_PACKET)
  			/* K3 optimized for LTE -> */
  			//dev_kfree_skb_any(skb);
  			skb_queue_tail(&dev->freeq, skb);
  			/* <- K3 optimized for LTE */
  		else
  			usbnet_skb_return(dev, skb);
  		return;
  	}
  
  	netif_dbg(dev, rx_err, dev->net, "drop\n");
  	dev->net->stats.rx_errors++;
  done:
  	skb_queue_tail(&dev->done, skb);
  }
  
  /*-------------------------------------------------------------------------*/
  
  static void rx_complete (struct urb *urb)
  {
  	struct sk_buff		*skb = (struct sk_buff *) urb->context;
  	struct skb_data		*entry = (struct skb_data *) skb->cb;
  	struct usbnet		*dev = entry->dev;
  	int			urb_status = urb->status;
  
  	skb_put (skb, urb->actual_length);
  	entry->state = rx_done;
  	entry->urb = NULL;
  
  	switch (urb_status) {
  	/* success */
  	case 0:
  		if (skb->len < dev->net->hard_header_len) {
  			entry->state = rx_cleanup;
  			dev->net->stats.rx_errors++;
  			dev->net->stats.rx_length_errors++;
  			netif_dbg(dev, rx_err, dev->net,
  				  "rx length %d\n", skb->len);
  		}
  		break;
  
  	/* stalls need manual reset. this is rare ... except that
  	 * when going through USB 2.0 TTs, unplug appears this way.
  	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
  	 * storm, recovering as needed.
  	 */
  	case -EPIPE:
  		dev->net->stats.rx_errors++;
  		usbnet_defer_kevent (dev, EVENT_RX_HALT);
  		// FALLTHROUGH
  
  	/* software-driven interface shutdown */
  	case -ECONNRESET:		/* async unlink */
  	case -ESHUTDOWN:		/* hardware gone */
  		netif_dbg(dev, ifdown, dev->net,
  			  "rx shutdown, code %d\n", urb_status);
  		goto block;
  
  	/* we get controller i/o faults during khubd disconnect() delays.
  	 * throttle down resubmits, to avoid log floods; just temporarily,
  	 * so we still recover when the fault isn't a khubd delay.
  	 */
  	case -EPROTO:
  	case -ETIME:
  	case -EILSEQ:
  		dev->net->stats.rx_errors++;
  		if (!timer_pending (&dev->delay)) {
  			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
  			netif_dbg(dev, link, dev->net,
  				  "rx throttle %d\n", urb_status);
  		}
  block:
  		entry->state = rx_cleanup;
  		entry->urb = urb;
  		urb = NULL;
  		break;
  
  	/* data overrun ... flush fifo? */
  	case -EOVERFLOW:
  		dev->net->stats.rx_over_errors++;
  		// FALLTHROUGH
  
  	default:
  		entry->state = rx_cleanup;
  		dev->net->stats.rx_errors++;
  		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
  		break;
  	}
  
  	defer_bh(dev, skb, &dev->rxq);
  
  	if (urb) {
  		/* K3 optimized for LTE -> */
  		/* Using fixed rx buffers, rx_submit shall only be called when a buffer
  		is processed */
  #if 0
  		if (netif_running (dev->net) &&
  		    !test_bit (EVENT_RX_HALT, &dev->flags)) {
  			rx_submit (dev, urb, GFP_ATOMIC);
  			return;
  		}
  #endif
  		/* <- K3 optimized for LTE */
  		usb_free_urb (urb);
  	}
  
  	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
  }
  
  static void intr_complete (struct urb *urb)
  {
  	struct usbnet	*dev = urb->context;
  	int		status = urb->status;
  
  	switch (status) {
  	/* success */
  	case 0:
  		dev->driver_info->status(dev, urb);
  		break;
  
  	/* software-driven interface shutdown */
  	case -ENOENT:		/* urb killed */
  	case -ESHUTDOWN:	/* hardware gone */
  		netif_dbg(dev, ifdown, dev->net,
  			  "intr shutdown, code %d\n", status);
  		return;
  
  	/* NOTE:  not throttling like RX/TX, since this endpoint
  	 * already polls infrequently
  	 */
  	default:
  		netdev_dbg(dev->net, "intr status %d\n", status);
  		break;
  	}
  
  	if (!netif_running (dev->net))
  		return;
  
  	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
  	status = usb_submit_urb (urb, GFP_ATOMIC);
  	if (status != 0)
  		netif_err(dev, timer, dev->net,
  			  "intr resubmit --> %d\n", status);
  }
  
  /*-------------------------------------------------------------------------*/
  void usbnet_pause_rx(struct usbnet *dev)
  {
  	set_bit(EVENT_RX_PAUSED, &dev->flags);
  
  	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
  }
  EXPORT_SYMBOL_GPL(usbnet_pause_rx);
  
  void usbnet_resume_rx(struct usbnet *dev)
  {
  	struct sk_buff *skb;
  	int num = 0;
  
  	clear_bit(EVENT_RX_PAUSED, &dev->flags);
  
  	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
  		usbnet_skb_return(dev, skb);
  		num++;
  	}
  
  	tasklet_schedule(&dev->bh);
  
  	netif_dbg(dev, rx_status, dev->net,
  		  "paused rx queue disabled, %d skbs requeued\n", num);
  }
  EXPORT_SYMBOL_GPL(usbnet_resume_rx);
  
  void usbnet_purge_paused_rxq(struct usbnet *dev)
  {
  	skb_queue_purge(&dev->rxq_pause);
  }
  EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
  
  /*-------------------------------------------------------------------------*/
  
  // unlink pending rx/tx; completion handlers do all other cleanup
  
  static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
  {
  	unsigned long		flags;
  	struct sk_buff		*skb, *skbnext;
  	int			count = 0;
  
  	spin_lock_irqsave (&q->lock, flags);
  	skb_queue_walk_safe(q, skb, skbnext) {
  		struct skb_data		*entry;
  		struct urb		*urb;
  		int			retval;
  
  		entry = (struct skb_data *) skb->cb;
  		urb = entry->urb;
  
  		// during some PM-driven resume scenarios,
  		// these (async) unlinks complete immediately
  		usb_get_urb(urb);
  		retval = usb_unlink_urb (urb);
  		if (retval != -EINPROGRESS && retval != 0)
  			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
  		else
  			count++;
  		usb_put_urb(urb);
  	}
  	spin_unlock_irqrestore (&q->lock, flags);
  	return count;
  }
  
  // Flush all pending rx urbs
  // minidrivers may need to do this when the MTU changes
  
  void usbnet_unlink_rx_urbs(struct usbnet *dev)
  {
  	if (netif_running(dev->net)) {
  		(void) unlink_urbs (dev, &dev->rxq);
  		tasklet_schedule(&dev->bh);
  	}
  }
  EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
  
  /*-------------------------------------------------------------------------*/
  
  // precondition: never called in_interrupt
  static void usbnet_terminate_urbs(struct usbnet *dev)
  {
  	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
  	DECLARE_WAITQUEUE(wait, current);
  	int temp;
  
  	/* ensure there are no more active urbs */
  	add_wait_queue(&unlink_wakeup, &wait);
  	set_current_state(TASK_UNINTERRUPTIBLE);
  	dev->wait = &unlink_wakeup;
  	temp = unlink_urbs(dev, &dev->txq) +
  		unlink_urbs(dev, &dev->rxq);
  
  	/* maybe wait for deletions to finish. */
  	while (!skb_queue_empty(&dev->rxq)
  		&& !skb_queue_empty(&dev->txq)
  		&& !skb_queue_empty(&dev->done)) {
  			schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
  			set_current_state(TASK_UNINTERRUPTIBLE);
  			netif_dbg(dev, ifdown, dev->net,
  				  "waited for %d urb completions\n", temp);
  	}
  	set_current_state(TASK_RUNNING);
  	dev->wait = NULL;
  	remove_wait_queue(&unlink_wakeup, &wait);
  }
  
  int usbnet_stop (struct net_device *net)
  {
  	struct usbnet		*dev = netdev_priv(net);
  	struct driver_info	*info = dev->driver_info;
  	struct sk_buff*		skb;
  	int			retval;
  
  	K3_DBG_LOG("----usbnet_stop\n");
  	mutex_lock(&sr_mutex);
  
  	//netif_carrier_off(net);
  	clear_bit(EVENT_DEV_OPEN, &dev->flags);
  	netif_stop_queue (net);
  
  	netif_info(dev, ifdown, dev->net,
  		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
  		   net->stats.rx_packets, net->stats.tx_packets,
  		   net->stats.rx_errors, net->stats.tx_errors);
  
  	if (info == NULL) {
  		netif_info(dev, ifdown, dev->net,"close a disconnect usbnet\n");
  		mutex_unlock(&sr_mutex);
  		return 0;
  	}
  
  	/* allow minidriver to stop correctly (wireless devices to turn off
  	 * radio etc) */
  	if (info->stop) {
  		retval = info->stop(dev);
  		if (retval < 0)
  			netif_info(dev, ifdown, dev->net,
  				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
  				   retval,
  				   dev->udev->bus->bus_name, dev->udev->devpath,
  				   info->description);
  	}
  
  	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
  		usbnet_terminate_urbs(dev);
  
  	usb_kill_urb(dev->interrupt);
  
  	usbnet_purge_paused_rxq(dev);
  
  	/* deferred work (task, timer, softirq) must also stop.
  	 * can't flush_scheduled_work() until we drop rtnl (later),
  	 * else workers could deadlock; so make workers a NOP.
  	 */
  	dev->flags = 0;
  	del_timer_sync (&dev->delay);
  	tasklet_kill (&dev->bh);
  
  	/* K3 optimized for LTE -> */
  	while ((skb = skb_dequeue(&dev->freeq)) != NULL)
  		dev_kfree_skb_any(skb);
  	/* <- K3 optimized for LTE */
  
  	if (info->manage_power)
  		info->manage_power(dev, 0);
  	else
  		usb_autopm_put_interface(dev->intf);
  
  	mutex_unlock(&sr_mutex);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usbnet_stop);
  
  /*-------------------------------------------------------------------------*/
  
  // posts reads, and enables write queuing
  
  // precondition: never called in_interrupt
  int usbnet_reopen (struct net_device *net)
  {
  	struct usbnet		*dev = netdev_priv(net);
  	int			i, retval = 0;
  	struct driver_info	*info = dev->driver_info;
  	struct sk_buff*		skb;
  	K3_DBG_LOG("----usbnet_reopen\n");
  
  	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
  		netif_info(dev, ifup, dev->net,
  			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
  			   retval,
  			   dev->udev->bus->bus_name,
  			   dev->udev->devpath,
  			   info->description);
  		goto done_nopm;
  	}
  
  	// put into "known safe" state
  	if (info->reset && (retval = info->reset (dev)) < 0) {
  		netif_info(dev, ifup, dev->net,
  			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
  			   retval,
  			   dev->udev->bus->bus_name,
  			   dev->udev->devpath,
  			   info->description);
  		goto done;
  	}
  
  	// insist peer be connected
  	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
  		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
  		goto done;
  	}
  
  	/* start any status interrupt transfer */
  	if (dev->interrupt) {
  		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
  		if (retval < 0) {
  			netif_err(dev, ifup, dev->net,
  				  "intr submit %d\n", retval);
  			goto done;
  		}
  	}
  
  	netif_start_queue (net);
  
  	/* K3 optimized for LTE -> */
  	for (i = 0; i < NUM_OF_RX_BUF; i++) {
  		skb = alloc_skb(dev->rx_urb_size + NET_IP_ALIGN, GFP_KERNEL);
  		if (skb == NULL) {
  			netif_err(dev, ifup, dev->net, "no rx skb\n");
  			retval = -ENOMEM;
  			/* free allocated skbs */
  			while ((skb = skb_dequeue(&dev->freeq)) != NULL)
  				dev_kfree_skb_any(skb);
  			goto done;
  		}
  		/* skbs in freeq have reserved IP align, don't reserve
  		in rx_submit again !! */
  		skb_reserve (skb, NET_IP_ALIGN);
  
  		__skb_queue_tail(&dev->freeq, skb);
  	}
  	/* <- K3 optimized for LTE */
  
  	// delay posting reads until we're fully open
  	tasklet_schedule (&dev->bh);
  	if (info->manage_power) {
  		retval = info->manage_power(dev, 0);
  		if (retval < 0)
  			goto done;
  		usb_autopm_put_interface(dev->intf);
  	}
  	return retval;
  
  done:
  	usb_autopm_put_interface(dev->intf);
  done_nopm:
  	return retval;
  }
  
  int usbnet_open (struct net_device *net)
  {
  	struct usbnet		*dev = netdev_priv(net);
  	int			i, retval = 0;
  	struct driver_info	*info = dev->driver_info;
  	struct sk_buff*		skb;
  
  	K3_DBG_LOG("----usbnet_open\n");
  
  	if (test_bit(EVENT_DEV_DISCONNECTED, &dev->flags)) {
  		K3_DBG_LOG("----usbnet open on disconnected state\n");
  		goto done_nopm;
  	}
  
  	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
  		netif_info(dev, ifup, dev->net,
  			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
  			   retval,
  			   dev->udev->bus->bus_name,
  			   dev->udev->devpath,
  			   info->description);
  		goto done_nopm;
  	}
  
  	// put into "known safe" state
  	if (info->reset && (retval = info->reset (dev)) < 0) {
  		netif_info(dev, ifup, dev->net,
  			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
  			   retval,
  			   dev->udev->bus->bus_name,
  			   dev->udev->devpath,
  			   info->description);
  		goto done;
  	}
  
  	// insist peer be connected
  	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
  		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
  		goto done;
  	}
  
  	/* start any status interrupt transfer */
  	if (dev->interrupt) {
  		retval = usb_submit_urb (dev->interrupt, GFP_KERNEL);
  		if (retval < 0) {
  			netif_err(dev, ifup, dev->net,
  				  "intr submit %d\n", retval);
  			goto done;
  		}
  	}
  
  	set_bit(EVENT_DEV_OPEN, &dev->flags);
  	netif_start_queue (net);
  	netif_info(dev, ifup, dev->net,
  		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
  		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
  		   dev->net->mtu,
  		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
  		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
  		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
  		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
  		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
  		   "simple");
  
  	/* K3 optimized for LTE -> */
  	for (i = 0; i < NUM_OF_RX_BUF; i++) {
  		skb = alloc_skb(dev->rx_urb_size + NET_IP_ALIGN, GFP_KERNEL);
  		if (skb == NULL) {
  			netif_err(dev, ifup, dev->net, "no rx skb\n");
  			retval = -ENOMEM;
  			/* free allocated skbs */
  			while ((skb = skb_dequeue(&dev->freeq)) != NULL)
  				dev_kfree_skb_any(skb);
  			goto done;
  		}
  		/* skbs in freeq have reserved IP align, don't reserve
  		in rx_submit again !! */
  		skb_reserve (skb, NET_IP_ALIGN);
  
  		__skb_queue_tail(&dev->freeq, skb);
  	}
  	/* <- K3 optimized for LTE */
  
  	// delay posting reads until we're fully open
  	tasklet_schedule (&dev->bh);
  	if (info->manage_power) {
  		retval = info->manage_power(dev, 0);
  		if (retval < 0)
  			goto done;
  		usb_autopm_put_interface(dev->intf);
  	}
  	return retval;
  
  done:
  	usb_autopm_put_interface(dev->intf);
  done_nopm:
  	return retval;
  }
  EXPORT_SYMBOL_GPL(usbnet_open);
  
  /*-------------------------------------------------------------------------*/
  
  /* ethtool methods; minidrivers may need to add some more, but
   * they'll probably want to use this base set.
   */
  
  int usbnet_get_settings (struct net_device *net, struct ethtool_cmd *cmd)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	if (!dev->mii.mdio_read)
  		return -EOPNOTSUPP;
  
  	return mii_ethtool_gset(&dev->mii, cmd);
  }
  EXPORT_SYMBOL_GPL(usbnet_get_settings);
  
  int usbnet_set_settings (struct net_device *net, struct ethtool_cmd *cmd)
  {
  	struct usbnet *dev = netdev_priv(net);
  	int retval;
  
  	if (!dev->mii.mdio_write)
  		return -EOPNOTSUPP;
  
  	retval = mii_ethtool_sset(&dev->mii, cmd);
  
  	if (test_bit(EVENT_DEV_DISCONNECTED, &dev->flags)) {
  		K3_DBG_LOG("----usbnet_set_settings on disconnected state\n");
  		return retval;
  	}
  
  	/* link speed/duplex might have changed */
  	if (dev->driver_info->link_reset)
  		dev->driver_info->link_reset(dev);
  
  	return retval;
  
  }
  EXPORT_SYMBOL_GPL(usbnet_set_settings);
  
  u32 usbnet_get_link (struct net_device *net)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	if (test_bit(EVENT_DEV_DISCONNECTED, &dev->flags)) {
  		K3_DBG_LOG("----usbnet_get_link on disconnected state\n");
  		return 0;
  	}
  
  	/* If a check_connect is defined, return its result */
  	if (dev->driver_info->check_connect)
  		return dev->driver_info->check_connect (dev) == 0;
  
  	/* if the device has mii operations, use those */
  	if (dev->mii.mdio_read)
  		return mii_link_ok(&dev->mii);
  
  	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
  	return ethtool_op_get_link(net);
  }
  EXPORT_SYMBOL_GPL(usbnet_get_link);
  
  int usbnet_nway_reset(struct net_device *net)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	if (!dev->mii.mdio_write)
  		return -EOPNOTSUPP;
  
  	return mii_nway_restart(&dev->mii);
  }
  EXPORT_SYMBOL_GPL(usbnet_nway_reset);
  
  void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	if (test_bit(EVENT_DEV_DISCONNECTED, &dev->flags)) {
  		K3_DBG_LOG("----usbnet_get_drvinfo on disconnected state\n");
  		return;
  	}
  
  	strncpy (info->driver, dev->driver_name, sizeof info->driver);
  	strncpy (info->version, DRIVER_VERSION, sizeof info->version);
  	strncpy (info->fw_version, dev->driver_info->description,
  		sizeof info->fw_version);
  	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
  }
  EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
  
  u32 usbnet_get_msglevel (struct net_device *net)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	return dev->msg_enable;
  }
  EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
  
  void usbnet_set_msglevel (struct net_device *net, u32 level)
  {
  	struct usbnet *dev = netdev_priv(net);
  
  	dev->msg_enable = level;
  }
  EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
  
  /* drivers may override default ethtool_ops in their bind() routine */
  static const struct ethtool_ops usbnet_ethtool_ops = {
  	.get_settings		= usbnet_get_settings,
  	.set_settings		= usbnet_set_settings,
  	.get_link		= usbnet_get_link,
  	.nway_reset		= usbnet_nway_reset,
  	.get_drvinfo		= usbnet_get_drvinfo,
  	.get_msglevel		= usbnet_get_msglevel,
  	.set_msglevel		= usbnet_set_msglevel,
  };
  
  /*-------------------------------------------------------------------------*/
  
  /* work that cannot be done in interrupt context uses keventd.
   *
   * NOTE:  with 2.5 we could do more of this using completion callbacks,
   * especially now that control transfers can be queued.
   */
  static void
  kevent (struct work_struct *work)
  {
  	struct usbnet		*dev =
  		container_of(work, struct usbnet, kevent);
  	int			status;
  
  	/* usb_clear_halt() needs a thread context */
  	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
  		unlink_urbs (dev, &dev->txq);
  		status = usb_autopm_get_interface(dev->intf);
  		if (status < 0)
  			goto fail_pipe;
  		status = usb_clear_halt (dev->udev, dev->out);
  		usb_autopm_put_interface(dev->intf);
  		if (status < 0 &&
  		    status != -EPIPE &&
  		    status != -ESHUTDOWN) {
  			if (netif_msg_tx_err (dev))
  fail_pipe:
  				netdev_err(dev->net, "can't clear tx halt, status %d\n",
  					   status);
  		} else {
  			clear_bit (EVENT_TX_HALT, &dev->flags);
  			if (status != -ESHUTDOWN)
  				netif_wake_queue (dev->net);
  		}
  	}
  	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
  		unlink_urbs (dev, &dev->rxq);
  		status = usb_autopm_get_interface(dev->intf);
  		if (status < 0)
  			goto fail_halt;
  		status = usb_clear_halt (dev->udev, dev->in);
  		usb_autopm_put_interface(dev->intf);
  		if (status < 0 &&
  		    status != -EPIPE &&
  		    status != -ESHUTDOWN) {
  			if (netif_msg_rx_err (dev))
  fail_halt:
  				netdev_err(dev->net, "can't clear rx halt, status %d\n",
  					   status);
  		} else {
  			clear_bit (EVENT_RX_HALT, &dev->flags);
  			tasklet_schedule (&dev->bh);
  		}
  	}
  
  	/* tasklet could resubmit itself forever if memory is tight */
  	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
  		struct urb	*urb = NULL;
  		int resched = 1;
  		int ret;
  
  		if (netif_running (dev->net))
  			urb = usb_alloc_urb (0, GFP_KERNEL);
  		else
  			clear_bit (EVENT_RX_MEMORY, &dev->flags);
  		if (urb != NULL) {
  			clear_bit (EVENT_RX_MEMORY, &dev->flags);
  			status = usb_autopm_get_interface(dev->intf);
  			if (status < 0) {
  				usb_free_urb(urb);
  				goto fail_lowmem;
  			}
  			ret = rx_submit (dev, urb, GFP_KERNEL);
  			if (ret == -ENOLINK || ret == -ENOMEM)
  				resched = 0;
  			usb_autopm_put_interface(dev->intf);
  fail_lowmem:
  			if (resched)
  				tasklet_schedule (&dev->bh);
  		}
  	}
  
  	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
  		struct driver_info	*info = dev->driver_info;
  		int			retval = 0;
  
  		clear_bit (EVENT_LINK_RESET, &dev->flags);
  		status = usb_autopm_get_interface(dev->intf);
  		if (status < 0)
  			goto skip_reset;
  		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
  			usb_autopm_put_interface(dev->intf);
  skip_reset:
  			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
  				    retval,
  				    dev->udev->bus->bus_name,
  				    dev->udev->devpath,
  				    info->description);
  		} else {
  			usb_autopm_put_interface(dev->intf);
  		}
  	}
  
  	if (dev->flags)
  		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
  }
  
  /*-------------------------------------------------------------------------*/
  
  static void tx_complete (struct urb *urb)
  {
  	struct sk_buff		*skb = (struct sk_buff *) urb->context;
  	struct skb_data		*entry = (struct skb_data *) skb->cb;
  	struct usbnet		*dev = entry->dev;
  
  	if (urb->status == 0) {
  		if (!(dev->driver_info->flags & FLAG_MULTI_PACKET))
  			dev->net->stats.tx_packets++;
  		dev->net->stats.tx_bytes += entry->length;
  	} else {
  		dev->net->stats.tx_errors++;
  
  		K3_DBG_LOG("----tx error: %d\n", urb->status);
  
  		switch (urb->status) {
  		case -EPIPE:
  			usbnet_defer_kevent (dev, EVENT_TX_HALT);
  			break;
  
  		/* software-driven interface shutdown */
  		case -ECONNRESET:		// async unlink
  		case -ESHUTDOWN:		// hardware gone
  			break;
  
  		// like rx, tx gets controller i/o faults during khubd delays
  		// and so it uses the same throttling mechanism.
  		case -EPROTO:
  		case -ETIME:
  		case -EILSEQ:
  			usb_mark_last_busy(dev->udev);
  			if (!timer_pending (&dev->delay)) {
  				mod_timer (&dev->delay,
  					jiffies + THROTTLE_JIFFIES);
  				netif_dbg(dev, link, dev->net,
  					  "tx throttle %d\n", urb->status);
  			}
  			netif_stop_queue (dev->net);
  			break;
  		default:
  			netif_dbg(dev, tx_err, dev->net,
  				  "tx err %d\n", entry->urb->status);
  			break;
  		}
  	}
  
  	usb_autopm_put_interface_async(dev->intf);
  	urb->dev = NULL;
  	entry->state = tx_done;
  	defer_bh(dev, skb, &dev->txq);
  }
  
  /*-------------------------------------------------------------------------*/
  
  void usbnet_tx_timeout (struct net_device *net)
  {
  	struct usbnet		*dev = netdev_priv(net);
  
  	unlink_urbs (dev, &dev->txq);
  	tasklet_schedule (&dev->bh);
  
  	// FIXME: device recovery -- reset?
  }
  EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
  
  /*-------------------------------------------------------------------------*/
  
  netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
  				     struct net_device *net)
  {
  	struct usbnet		*dev = netdev_priv(net);
  	int			length;
  	struct urb		*urb = NULL;
  	struct skb_data		*entry;
  	struct driver_info	*info = dev->driver_info;
  	unsigned long		flags;
  	int retval;
  
  	if (test_bit(EVENT_DEV_DISCONNECTED, &dev->flags)) {
  		net->trans_start = jiffies;
  		K3_DBG_LOG("----start xmit on disconnected state\n");
  		return NETDEV_TX_OK;
  	}
  
  	// some devices want funky USB-level framing, for
  	// win32 driver (usually) and/or hardware quirks
  	if (info->tx_fixup) {
  		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
  		if (!skb) {
  			if (netif_msg_tx_err(dev)) {
  				netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
  				goto drop;
  			} else {
  				/* cdc_ncm collected packet; waits for more */
  				goto not_drop;
  			}
  		}
  	}
  	length = skb->len;
  
  	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
  		netif_dbg(dev, tx_err, dev->net, "no urb\n");
  		goto drop;
  	}
  
  	entry = (struct skb_data *) skb->cb;
  	entry->urb = urb;
  	entry->dev = dev;
  	entry->state = tx_start;
  	entry->length = length;
  
  	usb_fill_bulk_urb (urb, dev->udev, dev->out,
  			skb->data, skb->len, tx_complete, skb);
  
  	/* don't assume the hardware handles USB_ZERO_PACKET
  	 * NOTE:  strictly conforming cdc-ether devices should expect
  	 * the ZLP here, but ignore the one-byte packet.
  	 * NOTE2: CDC NCM specification is different from CDC ECM when
  	 * handling ZLP/short packets, so cdc_ncm driver will make short
  	 * packet itself if needed.
  	 */
  	if (length % dev->maxpacket == 0) {
  		if (!(info->flags & FLAG_SEND_ZLP)) {
  			if (!(info->flags & FLAG_MULTI_PACKET)) {
  				urb->transfer_buffer_length++;
  				if (skb_tailroom(skb)) {
  					skb->data[skb->len] = 0;
  					__skb_put(skb, 1);
  				}
  			}
  		} else
  			urb->transfer_flags |= URB_ZERO_PACKET;
  	}
  
  	spin_lock_irqsave(&dev->txq.lock, flags);
  	retval = usb_autopm_get_interface_async(dev->intf);
  	if (retval < 0) {
  		spin_unlock_irqrestore(&dev->txq.lock, flags);
  		goto drop;
  	}
  
  #ifdef CONFIG_PM
  	/* if this triggers the device is still a sleep */
  	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
  		/* transmission will be done in resume */
  		usb_anchor_urb(urb, &dev->deferred);
  		/* no use to process more packets */
  		netif_stop_queue(net);
  		spin_unlock_irqrestore(&dev->txq.lock, flags);
  		//netdev_dbg(dev->net, "Delaying transmission for resumption\n");
  		K3_DBG_LOG("Delaying transmission for resumption\n");
  		goto deferred;
  	}
  #endif
  
  	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
  	case -EPIPE:
  		netif_stop_queue (net);
  		usbnet_defer_kevent (dev, EVENT_TX_HALT);
  		usb_autopm_put_interface_async(dev->intf);
  		break;
  	default:
  		usb_autopm_put_interface_async(dev->intf);
  		netif_dbg(dev, tx_err, dev->net,
  			  "tx: submit urb err %d\n", retval);
  		break;
  	case 0:
  		net->trans_start = jiffies;
  		__skb_queue_tail (&dev->txq, skb);
  		if (dev->txq.qlen >= TX_QLEN (dev))
  			netif_stop_queue (net);
  	}
  	spin_unlock_irqrestore (&dev->txq.lock, flags);
  
  	if (retval) {
  		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
  drop:
  		dev->net->stats.tx_dropped++;
  not_drop:
  		if (skb)
  			dev_kfree_skb_any (skb);
  		usb_free_urb (urb);
  	} else
  		netif_dbg(dev, tx_queued, dev->net,
  			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
  #ifdef CONFIG_PM
  deferred:
  #endif
  	return NETDEV_TX_OK;
  }
  EXPORT_SYMBOL_GPL(usbnet_start_xmit);
  
  /*-------------------------------------------------------------------------*/
  
  // tasklet (work deferred from completions, in_irq) or timer
  
  static void usbnet_bh (unsigned long param)
  {
  	struct usbnet		*dev = (struct usbnet *) param;
  	struct sk_buff		*skb;
  	struct skb_data		*entry;
  	int ret = 0;
  
  	while ((skb = skb_dequeue (&dev->done))) {
  		entry = (struct skb_data *) skb->cb;
  		switch (entry->state) {
  		case rx_done:
  			entry->state = rx_cleanup;
  			rx_process (dev, skb);
  			continue;
  		case tx_done:
  			usb_free_urb (entry->urb);
  			dev_kfree_skb (skb);
  			continue;
  		case rx_cleanup:
  			usb_free_urb (entry->urb);
  			/* K3 optimized for LTE -> */
  			//dev_kfree_skb (skb);
  			skb_queue_tail(&dev->freeq, skb);
  			/* <- K3 optimized for LTE */
  			continue;
  		default:
  			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
  		}
  	}
  
  	// waiting for all pending urbs to complete?
  	if (dev->wait) {
  		if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
  			wake_up (dev->wait);
  		}
  
  	// or are we maybe short a few urbs?
  	} else if (netif_running (dev->net) &&
  		   netif_device_present (dev->net) &&
  		   !timer_pending (&dev->delay) &&
  		   !test_bit (EVENT_RX_HALT, &dev->flags)) {
  		int	temp = dev->rxq.qlen;
  		int	qlen = RX_QLEN (dev);
  
  		if (temp < qlen) {
  			struct urb	*urb;
  			int		i;
  
  			/* K3 optimized for LTE -> */
  			// don't refill the queue all at once
  			for (i = 0; i < 10 && dev->freeq.qlen; i++) {
  				urb = usb_alloc_urb (0, GFP_ATOMIC);
  				if (urb != NULL) {
  					ret = rx_submit (dev, urb, GFP_ATOMIC);
  					if (ret == -ENOLINK)
  						return;
  				}
  			}
  			if (temp != dev->rxq.qlen)
  				netif_dbg(dev, link, dev->net,
  					  "rxqlen %d --> %d\n",
  					  temp, dev->rxq.qlen);
  #if 0
  			if (dev->rxq.qlen < qlen)
  				tasklet_schedule (&dev->bh);
  #endif
  			/* <- K3 optimized for LTE */
  		}
  		if (dev->txq.qlen < TX_QLEN (dev))
  			netif_wake_queue (dev->net);
  	}
  }
  
  
  /*-------------------------------------------------------------------------
   *
   * USB Device Driver support
   *
   *-------------------------------------------------------------------------*/
  
  void usbnet_stop_before_disconnect(struct usbnet *dev, struct net_device *net)
  {
  	struct driver_info	*info = dev->driver_info;
  	struct sk_buff*		skb;
  
  	netif_stop_queue (net);
  	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
  		usbnet_terminate_urbs(dev);
  
  	usb_kill_urb(dev->interrupt);
  	usbnet_purge_paused_rxq(dev);
  	del_timer_sync (&dev->delay);
  	tasklet_kill (&dev->bh);
  
  	/* K3 optimized for LTE -> */
  	while ((skb = skb_dequeue(&dev->freeq)) != NULL)
  		dev_kfree_skb_any(skb);
  	/* <- K3 optimized for LTE */
  
  	if (info->manage_power)
  		info->manage_power(dev, 0);
  	else
  		usb_autopm_put_interface(dev->intf);
  
  }
  
  void usbnet_disconnect (struct usb_interface *intf)
  {
  	struct usbnet		*dev;
  	struct usb_device	*xdev;
  	struct net_device	*net;
  	struct sk_buff          *skb;
  	struct urb              *res;
  
  	dev = usb_get_intfdata(intf);
  	usb_set_intfdata(intf, NULL);
  	if (!dev)
  		return;
  
  	xdev = interface_to_usbdev (intf);
  
  	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
  		   intf->dev.driver->name,
  		   xdev->bus->bus_name, xdev->devpath,
  		   dev->driver_info->description);
  
  	net = dev->net;
  
  	/*whatever, net will be kept*/
  	set_bit(EVENT_DEV_DISCONNECTED, &dev->flags);
  	cancel_work_sync(&dev->kevent);
  	netif_device_detach(net);
  
  	mutex_lock(&sr_mutex);
  	if (test_bit(EVENT_DEV_OPEN, &dev->flags))
  		usbnet_stop_before_disconnect(dev,net);
  
  	spin_lock_irq(&dev->txq.lock);
  	while ((res = usb_get_from_anchor(&dev->deferred))) {
  		K3_DBG_LOG("usbnet_disconnect free anchor urbs\n");
  		skb = (struct sk_buff *)res->context;
  		dev_kfree_skb_any(skb);
  		usb_free_urb(res);
  		usb_autopm_put_interface_async(dev->intf);
  	}
  	spin_unlock_irq(&dev->txq.lock);
  
  	if (dev->driver_info->unbind)
  		dev->driver_info->unbind(dev, intf);
  
  	device_del(&net->dev);
  	usb_put_dev(xdev);
  	net->dev.parent = NULL;
  	dev->intf = NULL;
  	dev->udev = NULL;
  	dev->driver_info = NULL;
  	dev->driver_name = NULL;
  	mutex_unlock(&sr_mutex);
  
  	return;
  
  	/*
  	unregister_netdev (net);
  
  	cancel_work_sync(&dev->kevent);
  
  	if (dev->driver_info->unbind)
  	dev->driver_info->unbind (dev, intf);
  
  	usb_kill_urb(dev->interrupt);
  	usb_free_urb(dev->interrupt);
  
  	free_netdev(net);
  	usb_put_dev (xdev);
  	*/
  }
  EXPORT_SYMBOL_GPL(usbnet_disconnect);
  
  static const struct net_device_ops usbnet_netdev_ops = {
  	.ndo_open		= usbnet_open,
  	.ndo_stop		= usbnet_stop,
  	.ndo_start_xmit		= usbnet_start_xmit,
  	.ndo_tx_timeout		= usbnet_tx_timeout,
  	.ndo_change_mtu		= usbnet_change_mtu,
  	.ndo_set_mac_address 	= eth_mac_addr,
  	.ndo_validate_addr	= eth_validate_addr,
  };
  
  /*-------------------------------------------------------------------------*/
  
  // precondition: never called in_interrupt
  
  static struct device_type wlan_type = {
  	.name	= "wlan",
  };
  
  static struct device_type wwan_type = {
  	.name	= "wwan",
  };
  
  int
  usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
  {
  	struct usbnet			*dev;
  	struct net_device		*net;
  	struct usb_host_interface	*interface;
  	struct driver_info		*info;
  	struct usb_device		*xdev;
  	int				status;
  	const char			*name;
  	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
  	int i, minor;
  	int reprobe_flag;
  
  	/* usbnet already took usb runtime pm, so have to enable the feature
  	 * for usb interface, otherwise usb_autopm_get_interface may return
  	 * failure if USB_SUSPEND(RUNTIME_PM) is enabled.
  	 */
  	if (!driver->supports_autosuspend) {
  		driver->supports_autosuspend = 1;
  		pm_runtime_enable(&udev->dev);
  	}
  
  	name = udev->dev.driver->name;
  	info = (struct driver_info *) prod->driver_info;
  	if (!info) {
  		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
  		return -ENODEV;
  	}
  	xdev = interface_to_usbdev (udev);
  	interface = udev->cur_altsetting;
  
  	usb_get_dev (xdev);
  
  	status = -ENOMEM;
  
  	minor = -1;
  	reprobe_flag = 1;
  	for (i = 0; i < USBNET_NET_MINORS; i++) {
  		if(usbnet_table[i] == NULL) {
  			reprobe_flag = 0;
  			minor = i;
  			break;
  		} else {
  			if (usbnet_table[i]->intf == NULL) {
  				minor = i;
  				break;
  			}
  		}
  	}
  	BUG_ON(minor < 0);
  
  	// set up our own records
  	if (!reprobe_flag) {
  		net = alloc_etherdev(sizeof(*dev));
  		if (!net) {
  			pr_err("[usbnet_probe]can't kmalloc dev\n");
  			goto out;
  		}
  
  		/* netdev_printk() needs this so do it as early as possible */
  		SET_NETDEV_DEV(net, &udev->dev);
  
  		dev = netdev_priv(net);
  
  		usbnet_table[minor] = dev;
  	}
  	else {
  		dev = usbnet_table[minor];
  		net = dev->net;
  	}
  
  	dev->udev = xdev;
  	dev->intf = udev;
  	dev->driver_info = info;
  	dev->driver_name = name;
  
  	if (!reprobe_flag) {
  		dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
  								| NETIF_MSG_PROBE | NETIF_MSG_LINK);
  		skb_queue_head_init (&dev->rxq);
  		skb_queue_head_init (&dev->txq);
  		skb_queue_head_init (&dev->done);
  		skb_queue_head_init (&dev->freeq);
  		skb_queue_head_init(&dev->rxq_pause);
  		dev->bh.func = usbnet_bh;
  		dev->bh.data = (unsigned long) dev;
  		INIT_WORK (&dev->kevent, kevent);
  		init_usb_anchor(&dev->deferred);
  		dev->delay.function = usbnet_bh;
  		dev->delay.data = (unsigned long) dev;
  		init_timer (&dev->delay);
  		mutex_init (&dev->phy_mutex);
  
  		dev->net = net;
  #if 0	/* On Android, some apps can only recognize rmnet, damn...*/
  		strcpy (net->name, "usb%d");
  #else
  		strcpy (net->name, "rmnet%d");
  #endif
  		memcpy (net->dev_addr, node_id, sizeof node_id);
  
  		/* rx and tx sides can use different message sizes;
  		 * bind() should set rx_urb_size in that case.
  		 */
  		dev->hard_mtu = net->mtu + net->hard_header_len;
  #if 0
  // dma_supported() is deeply broken on almost all architectures
  	// possible with some EHCI controllers
  	if (dma_supported (&udev->dev, DMA_BIT_MASK(64)))
  		net->features |= NETIF_F_HIGHDMA;
  #endif
  
  		net->netdev_ops = &usbnet_netdev_ops;
  		net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
  		net->ethtool_ops = &usbnet_ethtool_ops;
  	}
  
  	// allow device-specific bind/init procedures
  	// NOTE net->name still not usable ...
  	if (info->bind) {
  		status = info->bind (dev, udev);
  		if (status < 0)
  			goto out1;
  
  		// heuristic:  "usb%d" for links we know are two-host,
  		// else "eth%d" when there's reasonable doubt.  userspace
  		// can rename the link if it knows better.
  		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
  		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
  		     (net->dev_addr [0] & 0x02) == 0))
  			strcpy (net->name, "eth%d");
  		/* WLAN devices should always be named "wlan%d" */
  		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
  			strcpy(net->name, "wlan%d");
  		/* WWAN devices should always be named "wwan%d" */
  		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
  			strcpy(net->name, "wwan%d");
  
  		/* maybe the remote can't receive an Ethernet MTU */
  		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
  			net->mtu = dev->hard_mtu - net->hard_header_len;
  	} else if (!info->in || !info->out)
  		status = usbnet_get_endpoints (dev, udev);
  	else {
  		dev->in = usb_rcvbulkpipe (xdev, info->in);
  		dev->out = usb_sndbulkpipe (xdev, info->out);
  		if (!(info->flags & FLAG_NO_SETINT))
  			status = usb_set_interface (xdev,
  				interface->desc.bInterfaceNumber,
  				interface->desc.bAlternateSetting);
  		else
  			status = 0;
  
  	}
  	if (status >= 0 && dev->status)
  		status = init_status (dev, udev);
  	if (status < 0)
  		goto out3;
  
  	if (!dev->rx_urb_size)
  		dev->rx_urb_size = dev->hard_mtu;
  	dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1);
  
  	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
  		SET_NETDEV_DEVTYPE(net, &wlan_type);
  	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
  		SET_NETDEV_DEVTYPE(net, &wwan_type);
  
  	if(!reprobe_flag) {
  		status = register_netdev (net);
  		if (status)
  			goto out3;
  		netif_info(dev, probe, dev->net,
  		           "register '%s' at usb-%s-%s, %s, %pM\n",
  		           udev->dev.driver->name,
  		           xdev->bus->bus_name, xdev->devpath,
  		           dev->driver_info->description,
  		           net->dev_addr);
  
  		usb_set_intfdata (udev, dev);
  		netif_carrier_on(net);
  		netif_device_attach (net);
  	}else{
  		if(device_add(&net->dev))
  			pr_err("%s reprobe error: could not add device\n", dev_name(&net->dev));
  		dev->suspend_count = 0;
  
  		usb_set_intfdata (udev, dev);
  		netif_carrier_on(net);
  
  		mutex_lock(&sr_mutex);
  		if (test_bit(EVENT_DEV_OPEN, &dev->flags))
  			usbnet_reopen(net);
  		mutex_unlock(&sr_mutex);
  
  		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
  		clear_bit(EVENT_DEV_DISCONNECTED, &dev->flags);
  
  		netif_device_attach (net);
  	}
  
  	if (dev->driver_info->flags & FLAG_LINK_INTR)
  		netif_carrier_off(net);
  
  	return 0;
  
  out3:
  	if (info->unbind)
  		info->unbind (dev, udev);
  out1:
  	if (!reprobe_flag)
  		free_netdev(net);
  out:
  	usb_put_dev(xdev);
  	return status;
  }
  EXPORT_SYMBOL_GPL(usbnet_probe);
  
  /*-------------------------------------------------------------------------*/
  
  /*
   * suspend the whole driver as soon as the first interface is suspended
   * resume only when the last interface is resumed
   */
  
  int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
  {
  	struct usbnet		*dev = usb_get_intfdata(intf);
  
  	if (!dev->suspend_count++) {
  		spin_lock_irq(&dev->txq.lock);
  		/* don't autosuspend while transmitting */
  		if (dev->txq.qlen && (message.event & PM_EVENT_AUTO)) {
  			dev->suspend_count--;
  			spin_unlock_irq(&dev->txq.lock);
  			return -EBUSY;
  		} else {
  			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
  			spin_unlock_irq(&dev->txq.lock);
  		}
  		/*
  		 * accelerate emptying of the rx and queues, to avoid
  		 * having everything error out.
  		 */
  		netif_device_detach (dev->net);
  		usbnet_terminate_urbs(dev);
  		usb_kill_urb(dev->interrupt);
  
  		/*
  		 * reattach so runtime management can use and
  		 * wake the device
  		 */
  		netif_device_attach (dev->net);
  	}
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usbnet_suspend);
  
  int usbnet_resume (struct usb_interface *intf)
  {
  	struct usbnet		*dev = usb_get_intfdata(intf);
  	struct sk_buff          *skb;
  	struct urb              *res;
  	int                     retval;
  
  	if (!--dev->suspend_count) {
  		/* resume interrupt URBs */
  		if (dev->interrupt && test_bit(EVENT_DEV_OPEN, &dev->flags))
  			usb_submit_urb(dev->interrupt, GFP_NOIO);
  
  		spin_lock_irq(&dev->txq.lock);
  		while ((res = usb_get_from_anchor(&dev->deferred))) {
  
  			skb = (struct sk_buff *)res->context;
  			retval = usb_submit_urb(res, GFP_ATOMIC);
  			if (retval < 0) {
  				dev_kfree_skb_any(skb);
  				usb_free_urb(res);
  				usb_autopm_put_interface_async(dev->intf);
  			} else {
  				dev->net->trans_start = jiffies;
  				__skb_queue_tail(&dev->txq, skb);
  			}
  		}
  
  		smp_mb();
  		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
  		spin_unlock_irq(&dev->txq.lock);
  
  		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
  			if (!(dev->txq.qlen >= TX_QLEN(dev)))
  				netif_start_queue(dev->net);
  			tasklet_schedule (&dev->bh);
  		}
  	}
  	return 0;
  }
  EXPORT_SYMBOL_GPL(usbnet_resume);
  
  
  /*-------------------------------------------------------------------------*/
  
  static int __init usbnet_init(void)
  {
  	/* Compiler should optimize this out. */
  	BUILD_BUG_ON(
  		FIELD_SIZEOF(struct sk_buff, cb) < sizeof(struct skb_data));
  
  	random_ether_addr(node_id);
  	return 0;
  }
  module_init(usbnet_init);
  
  static void __exit usbnet_exit(void)
  {
  }
  module_exit(usbnet_exit);
  
  MODULE_AUTHOR("David Brownell");
  MODULE_DESCRIPTION("USB network driver framework");
  MODULE_LICENSE("GPL");
  