1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * USB Network driver infrastructure
   4 * Copyright (C) 2000-2005 by David Brownell
   5 * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
   6 */
   7
   8/*
   9 * This is a generic "USB networking" framework that works with several
  10 * kinds of full and high speed networking devices:  host-to-host cables,
  11 * smart usb peripherals, and actual Ethernet adapters.
  12 *
  13 * These devices usually differ in terms of control protocols (if they
  14 * even have one!) and sometimes they define new framing to wrap or batch
  15 * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
  16 * so interface (un)binding, endpoint I/O queues, fault handling, and other
  17 * issues can usefully be addressed by this framework.
  18 */
  19
 
 
 
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/netdevice.h>
  23#include <linux/etherdevice.h>
  24#include <linux/ctype.h>
  25#include <linux/ethtool.h>
  26#include <linux/workqueue.h>
  27#include <linux/mii.h>
  28#include <linux/usb.h>
  29#include <linux/usb/usbnet.h>
  30#include <linux/slab.h>
  31#include <linux/kernel.h>
  32#include <linux/pm_runtime.h>
  33
  34/*-------------------------------------------------------------------------*/
  35
  36/*
  37 * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
  38 * Several dozen bytes of IPv4 data can fit in two such transactions.
  39 * One maximum size Ethernet packet takes twenty four of them.
  40 * For high speed, each frame comfortably fits almost 36 max size
  41 * Ethernet packets (so queues should be bigger).
  42 *
  43 * The goal is to let the USB host controller be busy for 5msec or
  44 * more before an irq is required, under load.  Jumbograms change
  45 * the equation.
  46 */
  47#define	MAX_QUEUE_MEMORY	(60 * 1518)
  48#define	RX_QLEN(dev)		((dev)->rx_qlen)
  49#define	TX_QLEN(dev)		((dev)->tx_qlen)
  50
  51// reawaken network queue this soon after stopping; else watchdog barks
  52#define TX_TIMEOUT_JIFFIES	(5*HZ)
  53
  54/* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
  55 * us (it polls at HZ/4 usually) before we report too many false errors.
  56 */
  57#define THROTTLE_JIFFIES	(HZ/8)
  58
  59// between wakeups
  60#define UNLINK_TIMEOUT_MS	3
  61
  62/*-------------------------------------------------------------------------*/
  63
 
 
 
  64/* use ethtool to change the level for any given device */
  65static int msg_level = -1;
  66module_param (msg_level, int, 0);
  67MODULE_PARM_DESC (msg_level, "Override default message level");
  68
  69/*-------------------------------------------------------------------------*/
  70
  71static const char * const usbnet_event_names[] = {
  72	[EVENT_TX_HALT]		   = "EVENT_TX_HALT",
  73	[EVENT_RX_HALT]		   = "EVENT_RX_HALT",
  74	[EVENT_RX_MEMORY]	   = "EVENT_RX_MEMORY",
  75	[EVENT_STS_SPLIT]	   = "EVENT_STS_SPLIT",
  76	[EVENT_LINK_RESET]	   = "EVENT_LINK_RESET",
  77	[EVENT_RX_PAUSED]	   = "EVENT_RX_PAUSED",
  78	[EVENT_DEV_ASLEEP]	   = "EVENT_DEV_ASLEEP",
  79	[EVENT_DEV_OPEN]	   = "EVENT_DEV_OPEN",
  80	[EVENT_DEVICE_REPORT_IDLE] = "EVENT_DEVICE_REPORT_IDLE",
  81	[EVENT_NO_RUNTIME_PM]	   = "EVENT_NO_RUNTIME_PM",
  82	[EVENT_RX_KILL]		   = "EVENT_RX_KILL",
  83	[EVENT_LINK_CHANGE]	   = "EVENT_LINK_CHANGE",
  84	[EVENT_SET_RX_MODE]	   = "EVENT_SET_RX_MODE",
  85	[EVENT_NO_IP_ALIGN]	   = "EVENT_NO_IP_ALIGN",
  86};
  87
  88/* handles CDC Ethernet and many other network "bulk data" interfaces */
  89int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
  90{
  91	int				tmp;
  92	struct usb_host_interface	*alt = NULL;
  93	struct usb_host_endpoint	*in = NULL, *out = NULL;
  94	struct usb_host_endpoint	*status = NULL;
  95
  96	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
  97		unsigned	ep;
  98
  99		in = out = status = NULL;
 100		alt = intf->altsetting + tmp;
 101
 102		/* take the first altsetting with in-bulk + out-bulk;
 103		 * remember any status endpoint, just in case;
 104		 * ignore other endpoints and altsettings.
 105		 */
 106		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
 107			struct usb_host_endpoint	*e;
 108			int				intr = 0;
 109
 110			e = alt->endpoint + ep;
 111
 112			/* ignore endpoints which cannot transfer data */
 113			if (!usb_endpoint_maxp(&e->desc))
 114				continue;
 115
 116			switch (e->desc.bmAttributes) {
 117			case USB_ENDPOINT_XFER_INT:
 118				if (!usb_endpoint_dir_in(&e->desc))
 119					continue;
 120				intr = 1;
 121				fallthrough;
 122			case USB_ENDPOINT_XFER_BULK:
 123				break;
 124			default:
 125				continue;
 126			}
 127			if (usb_endpoint_dir_in(&e->desc)) {
 128				if (!intr && !in)
 129					in = e;
 130				else if (intr && !status)
 131					status = e;
 132			} else {
 133				if (!out)
 134					out = e;
 135			}
 136		}
 137		if (in && out)
 138			break;
 139	}
 140	if (!alt || !in || !out)
 141		return -EINVAL;
 142
 143	if (alt->desc.bAlternateSetting != 0 ||
 144	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
 145		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
 146				alt->desc.bAlternateSetting);
 147		if (tmp < 0)
 148			return tmp;
 149	}
 150
 151	dev->in = usb_rcvbulkpipe (dev->udev,
 152			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 153	dev->out = usb_sndbulkpipe (dev->udev,
 154			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 155	dev->status = status;
 156	return 0;
 157}
 158EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
 159
 160int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 161{
 162	u8		addr[ETH_ALEN];
 163	int 		tmp = -1, ret;
 164	unsigned char	buf [13];
 165
 166	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
 167	if (ret == 12)
 168		tmp = hex2bin(addr, buf, 6);
 169	if (tmp < 0) {
 170		dev_dbg(&dev->udev->dev,
 171			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
 172		if (ret >= 0)
 173			ret = -EINVAL;
 174		return ret;
 175	}
 176	eth_hw_addr_set(dev->net, addr);
 177	return 0;
 178}
 179EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 180
 181static void intr_complete (struct urb *urb)
 182{
 183	struct usbnet	*dev = urb->context;
 184	int		status = urb->status;
 185
 186	switch (status) {
 187	/* success */
 188	case 0:
 189		dev->driver_info->status(dev, urb);
 190		break;
 191
 192	/* software-driven interface shutdown */
 193	case -ENOENT:		/* urb killed */
 194	case -ESHUTDOWN:	/* hardware gone */
 195		netif_dbg(dev, ifdown, dev->net,
 196			  "intr shutdown, code %d\n", status);
 197		return;
 198
 199	/* NOTE:  not throttling like RX/TX, since this endpoint
 200	 * already polls infrequently
 201	 */
 202	default:
 203		netdev_dbg(dev->net, "intr status %d\n", status);
 204		break;
 205	}
 206
 207	status = usb_submit_urb (urb, GFP_ATOMIC);
 208	if (status != 0)
 209		netif_err(dev, timer, dev->net,
 210			  "intr resubmit --> %d\n", status);
 211}
 212
 213static int init_status (struct usbnet *dev, struct usb_interface *intf)
 214{
 215	char		*buf = NULL;
 216	unsigned	pipe = 0;
 217	unsigned	maxp;
 218	unsigned	period;
 219
 220	if (!dev->driver_info->status)
 221		return 0;
 222
 223	pipe = usb_rcvintpipe (dev->udev,
 224			dev->status->desc.bEndpointAddress
 225				& USB_ENDPOINT_NUMBER_MASK);
 226	maxp = usb_maxpacket(dev->udev, pipe);
 227
 228	/* avoid 1 msec chatter:  min 8 msec poll rate */
 229	period = max ((int) dev->status->desc.bInterval,
 230		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
 231
 232	buf = kmalloc (maxp, GFP_KERNEL);
 233	if (buf) {
 234		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
 235		if (!dev->interrupt) {
 236			kfree (buf);
 237			return -ENOMEM;
 238		} else {
 239			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
 240				buf, maxp, intr_complete, dev, period);
 241			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
 242			dev_dbg(&intf->dev,
 243				"status ep%din, %d bytes period %d\n",
 244				usb_pipeendpoint(pipe), maxp, period);
 245		}
 246	}
 247	return 0;
 248}
 249
 250/* Submit the interrupt URB if not previously submitted, increasing refcount */
 251int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
 252{
 253	int ret = 0;
 254
 255	WARN_ON_ONCE(dev->interrupt == NULL);
 256	if (dev->interrupt) {
 257		mutex_lock(&dev->interrupt_mutex);
 258
 259		if (++dev->interrupt_count == 1)
 260			ret = usb_submit_urb(dev->interrupt, mem_flags);
 261
 262		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
 263			dev->interrupt_count);
 264		mutex_unlock(&dev->interrupt_mutex);
 265	}
 266	return ret;
 267}
 268EXPORT_SYMBOL_GPL(usbnet_status_start);
 269
 270/* For resume; submit interrupt URB if previously submitted */
 271static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
 272{
 273	int ret = 0;
 274
 275	mutex_lock(&dev->interrupt_mutex);
 276	if (dev->interrupt_count) {
 277		ret = usb_submit_urb(dev->interrupt, mem_flags);
 278		dev_dbg(&dev->udev->dev,
 279			"submitted interrupt URB for resume\n");
 280	}
 281	mutex_unlock(&dev->interrupt_mutex);
 282	return ret;
 283}
 284
 285/* Kill the interrupt URB if all submitters want it killed */
 286void usbnet_status_stop(struct usbnet *dev)
 287{
 288	if (dev->interrupt) {
 289		mutex_lock(&dev->interrupt_mutex);
 290		WARN_ON(dev->interrupt_count == 0);
 291
 292		if (dev->interrupt_count && --dev->interrupt_count == 0)
 293			usb_kill_urb(dev->interrupt);
 294
 295		dev_dbg(&dev->udev->dev,
 296			"decremented interrupt URB count to %d\n",
 297			dev->interrupt_count);
 298		mutex_unlock(&dev->interrupt_mutex);
 299	}
 300}
 301EXPORT_SYMBOL_GPL(usbnet_status_stop);
 302
 303/* For suspend; always kill interrupt URB */
 304static void __usbnet_status_stop_force(struct usbnet *dev)
 305{
 306	if (dev->interrupt) {
 307		mutex_lock(&dev->interrupt_mutex);
 308		usb_kill_urb(dev->interrupt);
 309		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
 310		mutex_unlock(&dev->interrupt_mutex);
 311	}
 312}
 313
 314/* Passes this packet up the stack, updating its accounting.
 315 * Some link protocols batch packets, so their rx_fixup paths
 316 * can return clones as well as just modify the original skb.
 317 */
 318void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 319{
 320	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
 321	unsigned long flags;
 322	int	status;
 323
 324	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
 325		skb_queue_tail(&dev->rxq_pause, skb);
 326		return;
 327	}
 328
 329	/* only update if unset to allow minidriver rx_fixup override */
 330	if (skb->protocol == 0)
 331		skb->protocol = eth_type_trans (skb, dev->net);
 332
 333	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
 334	u64_stats_inc(&stats64->rx_packets);
 335	u64_stats_add(&stats64->rx_bytes, skb->len);
 336	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
 337
 338	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
 339		  skb->len + sizeof (struct ethhdr), skb->protocol);
 340	memset (skb->cb, 0, sizeof (struct skb_data));
 341
 342	if (skb_defer_rx_timestamp(skb))
 343		return;
 344
 345	status = netif_rx (skb);
 346	if (status != NET_RX_SUCCESS)
 347		netif_dbg(dev, rx_err, dev->net,
 348			  "netif_rx status %d\n", status);
 349}
 350EXPORT_SYMBOL_GPL(usbnet_skb_return);
 351
 352/* must be called if hard_mtu or rx_urb_size changed */
 353void usbnet_update_max_qlen(struct usbnet *dev)
 354{
 355	enum usb_device_speed speed = dev->udev->speed;
 356
 357	if (!dev->rx_urb_size || !dev->hard_mtu)
 358		goto insanity;
 359	switch (speed) {
 360	case USB_SPEED_HIGH:
 361		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
 362		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
 363		break;
 364	case USB_SPEED_SUPER:
 365	case USB_SPEED_SUPER_PLUS:
 366		/*
 367		 * Not take default 5ms qlen for super speed HC to
 368		 * save memory, and iperf tests show 2.5ms qlen can
 369		 * work well
 370		 */
 371		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
 372		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
 373		break;
 374	default:
 375insanity:
 376		dev->rx_qlen = dev->tx_qlen = 4;
 377	}
 378}
 379EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
 380
 381
 382/*-------------------------------------------------------------------------
 383 *
 384 * Network Device Driver (peer link to "Host Device", from USB host)
 385 *
 386 *-------------------------------------------------------------------------*/
 387
 388int usbnet_change_mtu (struct net_device *net, int new_mtu)
 389{
 390	struct usbnet	*dev = netdev_priv(net);
 391	int		ll_mtu = new_mtu + net->hard_header_len;
 392	int		old_hard_mtu = dev->hard_mtu;
 393	int		old_rx_urb_size = dev->rx_urb_size;
 394
 395	// no second zero-length packet read wanted after mtu-sized packets
 396	if ((ll_mtu % dev->maxpacket) == 0)
 397		return -EDOM;
 398	WRITE_ONCE(net->mtu, new_mtu);
 399
 400	dev->hard_mtu = net->mtu + net->hard_header_len;
 401	if (dev->rx_urb_size == old_hard_mtu) {
 402		dev->rx_urb_size = dev->hard_mtu;
 403		if (dev->rx_urb_size > old_rx_urb_size) {
 404			usbnet_pause_rx(dev);
 405			usbnet_unlink_rx_urbs(dev);
 406			usbnet_resume_rx(dev);
 407		}
 408	}
 409
 410	/* max qlen depend on hard_mtu and rx_urb_size */
 411	usbnet_update_max_qlen(dev);
 412
 413	return 0;
 414}
 415EXPORT_SYMBOL_GPL(usbnet_change_mtu);
 416
 417/* The caller must hold list->lock */
 418static void __usbnet_queue_skb(struct sk_buff_head *list,
 419			struct sk_buff *newsk, enum skb_state state)
 420{
 421	struct skb_data *entry = (struct skb_data *) newsk->cb;
 422
 423	__skb_queue_tail(list, newsk);
 424	entry->state = state;
 425}
 426
 427/*-------------------------------------------------------------------------*/
 428
 429/* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 430 * completion callbacks.  2.5 should have fixed those bugs...
 431 */
 432
 433static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
 434		struct sk_buff_head *list, enum skb_state state)
 435{
 436	unsigned long		flags;
 437	enum skb_state 		old_state;
 438	struct skb_data *entry = (struct skb_data *) skb->cb;
 439
 440	spin_lock_irqsave(&list->lock, flags);
 441	old_state = entry->state;
 442	entry->state = state;
 443	__skb_unlink(skb, list);
 444
 445	/* defer_bh() is never called with list == &dev->done.
 446	 * spin_lock_nested() tells lockdep that it is OK to take
 447	 * dev->done.lock here with list->lock held.
 448	 */
 449	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
 450
 451	__skb_queue_tail(&dev->done, skb);
 452	if (dev->done.qlen == 1)
 453		tasklet_schedule(&dev->bh);
 454	spin_unlock(&dev->done.lock);
 455	spin_unlock_irqrestore(&list->lock, flags);
 456	return old_state;
 457}
 458
 459/* some work can't be done in tasklets, so we use keventd
 460 *
 461 * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 462 * but tasklet_schedule() doesn't.  hope the failure is rare.
 463 */
 464void usbnet_defer_kevent (struct usbnet *dev, int work)
 465{
 466	set_bit (work, &dev->flags);
 467	if (!usbnet_going_away(dev)) {
 468		if (!schedule_work(&dev->kevent))
 469			netdev_dbg(dev->net,
 470				   "kevent %s may have been dropped\n",
 471				   usbnet_event_names[work]);
 472		else
 473			netdev_dbg(dev->net,
 474				   "kevent %s scheduled\n", usbnet_event_names[work]);
 475	}
 476}
 477EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
 478
 479/*-------------------------------------------------------------------------*/
 480
 481static void rx_complete (struct urb *urb);
 482
 483static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 484{
 485	struct sk_buff		*skb;
 486	struct skb_data		*entry;
 487	int			retval = 0;
 488	unsigned long		lockflags;
 489	size_t			size = dev->rx_urb_size;
 490
 491	/* prevent rx skb allocation when error ratio is high */
 492	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
 493		usb_free_urb(urb);
 494		return -ENOLINK;
 495	}
 496
 497	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
 498		skb = __netdev_alloc_skb(dev->net, size, flags);
 499	else
 500		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
 501	if (!skb) {
 502		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
 503		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 504		usb_free_urb (urb);
 505		return -ENOMEM;
 506	}
 507
 508	entry = (struct skb_data *) skb->cb;
 509	entry->urb = urb;
 510	entry->dev = dev;
 511	entry->length = 0;
 512
 513	usb_fill_bulk_urb (urb, dev->udev, dev->in,
 514		skb->data, size, rx_complete, skb);
 515
 516	spin_lock_irqsave (&dev->rxq.lock, lockflags);
 517
 518	if (netif_running (dev->net) &&
 519	    netif_device_present (dev->net) &&
 520	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
 521	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
 522	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
 523		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
 524		case -EPIPE:
 525			usbnet_defer_kevent (dev, EVENT_RX_HALT);
 526			break;
 527		case -ENOMEM:
 528			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 529			break;
 530		case -ENODEV:
 531			netif_dbg(dev, ifdown, dev->net, "device gone\n");
 532			netif_device_detach (dev->net);
 533			break;
 534		case -EHOSTUNREACH:
 535			retval = -ENOLINK;
 536			break;
 537		default:
 538			netif_dbg(dev, rx_err, dev->net,
 539				  "rx submit, %d\n", retval);
 540			tasklet_schedule (&dev->bh);
 541			break;
 542		case 0:
 543			if (!usbnet_going_away(dev))
 544				__usbnet_queue_skb(&dev->rxq, skb, rx_start);
 545		}
 546	} else {
 547		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
 548		retval = -ENOLINK;
 549	}
 550	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
 551	if (retval) {
 552		dev_kfree_skb_any (skb);
 553		usb_free_urb (urb);
 554	}
 555	return retval;
 556}
 557
 558
 559/*-------------------------------------------------------------------------*/
 560
 561static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
 562{
 563	if (dev->driver_info->rx_fixup &&
 564	    !dev->driver_info->rx_fixup (dev, skb)) {
 565		/* With RX_ASSEMBLE, rx_fixup() must update counters */
 566		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
 567			dev->net->stats.rx_errors++;
 568		return -EPROTO;
 569	}
 570	// else network stack removes extra byte if we forced a short packet
 571
 572	/* all data was already cloned from skb inside the driver */
 573	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
 574		return -EALREADY;
 575
 576	if (skb->len < ETH_HLEN) {
 577		dev->net->stats.rx_errors++;
 578		dev->net->stats.rx_length_errors++;
 579		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
 580		return -EPROTO;
 
 
 581	}
 582
 583	usbnet_skb_return(dev, skb);
 584	return 0;
 585}
 586
 587/*-------------------------------------------------------------------------*/
 588
 589static void rx_complete (struct urb *urb)
 590{
 591	struct sk_buff		*skb = (struct sk_buff *) urb->context;
 592	struct skb_data		*entry = (struct skb_data *) skb->cb;
 593	struct usbnet		*dev = entry->dev;
 594	int			urb_status = urb->status;
 595	enum skb_state		state;
 596
 597	skb_put (skb, urb->actual_length);
 598	state = rx_done;
 599	entry->urb = NULL;
 600
 601	switch (urb_status) {
 602	/* success */
 603	case 0:
 604		break;
 605
 606	/* stalls need manual reset. this is rare ... except that
 607	 * when going through USB 2.0 TTs, unplug appears this way.
 608	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
 609	 * storm, recovering as needed.
 610	 */
 611	case -EPIPE:
 612		dev->net->stats.rx_errors++;
 613		usbnet_defer_kevent (dev, EVENT_RX_HALT);
 614		fallthrough;
 615
 616	/* software-driven interface shutdown */
 617	case -ECONNRESET:		/* async unlink */
 618	case -ESHUTDOWN:		/* hardware gone */
 619		netif_dbg(dev, ifdown, dev->net,
 620			  "rx shutdown, code %d\n", urb_status);
 621		goto block;
 622
 623	/* we get controller i/o faults during hub_wq disconnect() delays.
 624	 * throttle down resubmits, to avoid log floods; just temporarily,
 625	 * so we still recover when the fault isn't a hub_wq delay.
 626	 */
 627	case -EPROTO:
 628	case -ETIME:
 629	case -EILSEQ:
 630		dev->net->stats.rx_errors++;
 631		if (!timer_pending (&dev->delay)) {
 632			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
 633			netif_dbg(dev, link, dev->net,
 634				  "rx throttle %d\n", urb_status);
 635		}
 636block:
 637		state = rx_cleanup;
 638		entry->urb = urb;
 639		urb = NULL;
 640		break;
 641
 642	/* data overrun ... flush fifo? */
 643	case -EOVERFLOW:
 644		dev->net->stats.rx_over_errors++;
 645		fallthrough;
 646
 647	default:
 648		state = rx_cleanup;
 649		dev->net->stats.rx_errors++;
 650		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
 651		break;
 652	}
 653
 654	/* stop rx if packet error rate is high */
 655	if (++dev->pkt_cnt > 30) {
 656		dev->pkt_cnt = 0;
 657		dev->pkt_err = 0;
 658	} else {
 659		if (state == rx_cleanup)
 660			dev->pkt_err++;
 661		if (dev->pkt_err > 20)
 662			set_bit(EVENT_RX_KILL, &dev->flags);
 663	}
 664
 665	state = defer_bh(dev, skb, &dev->rxq, state);
 666
 667	if (urb) {
 668		if (netif_running (dev->net) &&
 669		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
 670		    state != unlink_start) {
 671			rx_submit (dev, urb, GFP_ATOMIC);
 672			usb_mark_last_busy(dev->udev);
 673			return;
 674		}
 675		usb_free_urb (urb);
 676	}
 677	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
 678}
 679
 680/*-------------------------------------------------------------------------*/
 681void usbnet_pause_rx(struct usbnet *dev)
 682{
 683	set_bit(EVENT_RX_PAUSED, &dev->flags);
 684
 685	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
 686}
 687EXPORT_SYMBOL_GPL(usbnet_pause_rx);
 688
 689void usbnet_resume_rx(struct usbnet *dev)
 690{
 691	struct sk_buff *skb;
 692	int num = 0;
 693
 694	clear_bit(EVENT_RX_PAUSED, &dev->flags);
 695
 696	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
 697		usbnet_skb_return(dev, skb);
 698		num++;
 699	}
 700
 701	tasklet_schedule(&dev->bh);
 702
 703	netif_dbg(dev, rx_status, dev->net,
 704		  "paused rx queue disabled, %d skbs requeued\n", num);
 705}
 706EXPORT_SYMBOL_GPL(usbnet_resume_rx);
 707
 708void usbnet_purge_paused_rxq(struct usbnet *dev)
 709{
 710	skb_queue_purge(&dev->rxq_pause);
 711}
 712EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
 713
 714/*-------------------------------------------------------------------------*/
 715
 716// unlink pending rx/tx; completion handlers do all other cleanup
 717
 718static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
 719{
 720	unsigned long		flags;
 721	struct sk_buff		*skb;
 722	int			count = 0;
 723
 724	spin_lock_irqsave (&q->lock, flags);
 725	while (!skb_queue_empty(q)) {
 726		struct skb_data		*entry;
 727		struct urb		*urb;
 728		int			retval;
 729
 730		skb_queue_walk(q, skb) {
 731			entry = (struct skb_data *) skb->cb;
 732			if (entry->state != unlink_start)
 733				goto found;
 734		}
 735		break;
 736found:
 737		entry->state = unlink_start;
 738		urb = entry->urb;
 739
 740		/*
 741		 * Get reference count of the URB to avoid it to be
 742		 * freed during usb_unlink_urb, which may trigger
 743		 * use-after-free problem inside usb_unlink_urb since
 744		 * usb_unlink_urb is always racing with .complete
 745		 * handler(include defer_bh).
 746		 */
 747		usb_get_urb(urb);
 748		spin_unlock_irqrestore(&q->lock, flags);
 749		// during some PM-driven resume scenarios,
 750		// these (async) unlinks complete immediately
 751		retval = usb_unlink_urb (urb);
 752		if (retval != -EINPROGRESS && retval != 0)
 753			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
 754		else
 755			count++;
 756		usb_put_urb(urb);
 757		spin_lock_irqsave(&q->lock, flags);
 758	}
 759	spin_unlock_irqrestore (&q->lock, flags);
 760	return count;
 761}
 762
 763// Flush all pending rx urbs
 764// minidrivers may need to do this when the MTU changes
 765
 766void usbnet_unlink_rx_urbs(struct usbnet *dev)
 767{
 768	if (netif_running(dev->net)) {
 769		(void) unlink_urbs (dev, &dev->rxq);
 770		tasklet_schedule(&dev->bh);
 771	}
 772}
 773EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 774
 775/*-------------------------------------------------------------------------*/
 776
 777static void wait_skb_queue_empty(struct sk_buff_head *q)
 778{
 779	unsigned long flags;
 780
 781	spin_lock_irqsave(&q->lock, flags);
 782	while (!skb_queue_empty(q)) {
 783		spin_unlock_irqrestore(&q->lock, flags);
 784		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 785		set_current_state(TASK_UNINTERRUPTIBLE);
 786		spin_lock_irqsave(&q->lock, flags);
 787	}
 788	spin_unlock_irqrestore(&q->lock, flags);
 789}
 790
 791// precondition: never called in_interrupt
 792static void usbnet_terminate_urbs(struct usbnet *dev)
 793{
 794	DECLARE_WAITQUEUE(wait, current);
 795	int temp;
 796
 797	/* ensure there are no more active urbs */
 798	add_wait_queue(&dev->wait, &wait);
 799	set_current_state(TASK_UNINTERRUPTIBLE);
 800	temp = unlink_urbs(dev, &dev->txq) +
 801		unlink_urbs(dev, &dev->rxq);
 802
 803	/* maybe wait for deletions to finish. */
 804	wait_skb_queue_empty(&dev->rxq);
 805	wait_skb_queue_empty(&dev->txq);
 806	wait_skb_queue_empty(&dev->done);
 807	netif_dbg(dev, ifdown, dev->net,
 808		  "waited for %d urb completions\n", temp);
 809	set_current_state(TASK_RUNNING);
 810	remove_wait_queue(&dev->wait, &wait);
 811}
 812
 813int usbnet_stop (struct net_device *net)
 814{
 815	struct usbnet		*dev = netdev_priv(net);
 816	const struct driver_info *info = dev->driver_info;
 817	int			retval, pm, mpn;
 818
 819	clear_bit(EVENT_DEV_OPEN, &dev->flags);
 820	netif_stop_queue (net);
 821
 822	netif_info(dev, ifdown, dev->net,
 823		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 824		   net->stats.rx_packets, net->stats.tx_packets,
 825		   net->stats.rx_errors, net->stats.tx_errors);
 826
 827	/* to not race resume */
 828	pm = usb_autopm_get_interface(dev->intf);
 829	/* allow minidriver to stop correctly (wireless devices to turn off
 830	 * radio etc) */
 831	if (info->stop) {
 832		retval = info->stop(dev);
 833		if (retval < 0)
 834			netif_info(dev, ifdown, dev->net,
 835				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
 836				   retval,
 837				   dev->udev->bus->bus_name, dev->udev->devpath,
 838				   info->description);
 839	}
 840
 841	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
 842		usbnet_terminate_urbs(dev);
 843
 844	usbnet_status_stop(dev);
 845
 846	usbnet_purge_paused_rxq(dev);
 847
 848	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
 849
 850	/* deferred work (timer, softirq, task) must also stop */
 851	dev->flags = 0;
 852	del_timer_sync(&dev->delay);
 853	tasklet_kill(&dev->bh);
 854	cancel_work_sync(&dev->kevent);
 855
 856	/* We have cyclic dependencies. Those calls are needed
 857	 * to break a cycle. We cannot fall into the gaps because
 858	 * we have a flag
 859	 */
 860	tasklet_kill(&dev->bh);
 861	del_timer_sync(&dev->delay);
 862	cancel_work_sync(&dev->kevent);
 863
 864	if (!pm)
 865		usb_autopm_put_interface(dev->intf);
 866
 867	if (info->manage_power && mpn)
 868		info->manage_power(dev, 0);
 869	else
 870		usb_autopm_put_interface(dev->intf);
 871
 872	return 0;
 873}
 874EXPORT_SYMBOL_GPL(usbnet_stop);
 875
 876/*-------------------------------------------------------------------------*/
 877
 878// posts reads, and enables write queuing
 879
 880// precondition: never called in_interrupt
 881
 882int usbnet_open (struct net_device *net)
 883{
 884	struct usbnet		*dev = netdev_priv(net);
 885	int			retval;
 886	const struct driver_info *info = dev->driver_info;
 887
 888	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
 889		netif_info(dev, ifup, dev->net,
 890			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
 891			   retval,
 892			   dev->udev->bus->bus_name,
 893			   dev->udev->devpath,
 894			   info->description);
 895		goto done_nopm;
 896	}
 897
 898	// put into "known safe" state
 899	if (info->reset && (retval = info->reset (dev)) < 0) {
 900		netif_info(dev, ifup, dev->net,
 901			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
 902			   retval,
 903			   dev->udev->bus->bus_name,
 904			   dev->udev->devpath,
 905			   info->description);
 906		goto done;
 907	}
 908
 909	/* hard_mtu or rx_urb_size may change in reset() */
 910	usbnet_update_max_qlen(dev);
 911
 912	// insist peer be connected
 913	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
 914		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
 915		goto done;
 916	}
 917
 918	/* start any status interrupt transfer */
 919	if (dev->interrupt) {
 920		retval = usbnet_status_start(dev, GFP_KERNEL);
 921		if (retval < 0) {
 922			netif_err(dev, ifup, dev->net,
 923				  "intr submit %d\n", retval);
 924			goto done;
 925		}
 926	}
 927
 928	set_bit(EVENT_DEV_OPEN, &dev->flags);
 929	netif_start_queue (net);
 930	netif_info(dev, ifup, dev->net,
 931		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
 932		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
 933		   dev->net->mtu,
 934		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
 935		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
 936		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
 937		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
 938		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
 939		   "simple");
 940
 941	/* reset rx error state */
 942	dev->pkt_cnt = 0;
 943	dev->pkt_err = 0;
 944	clear_bit(EVENT_RX_KILL, &dev->flags);
 945
 946	// delay posting reads until we're fully open
 947	tasklet_schedule (&dev->bh);
 948	if (info->manage_power) {
 949		retval = info->manage_power(dev, 1);
 950		if (retval < 0) {
 951			retval = 0;
 952			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
 953		} else {
 954			usb_autopm_put_interface(dev->intf);
 955		}
 956	}
 957	return retval;
 958done:
 959	usb_autopm_put_interface(dev->intf);
 960done_nopm:
 961	return retval;
 962}
 963EXPORT_SYMBOL_GPL(usbnet_open);
 964
 965/*-------------------------------------------------------------------------*/
 966
 967/* ethtool methods; minidrivers may need to add some more, but
 968 * they'll probably want to use this base set.
 969 */
 970
 971/* These methods are written on the assumption that the device
 972 * uses MII
 973 */
 974int usbnet_get_link_ksettings_mii(struct net_device *net,
 975			      struct ethtool_link_ksettings *cmd)
 976{
 977	struct usbnet *dev = netdev_priv(net);
 978
 979	if (!dev->mii.mdio_read)
 980		return -EOPNOTSUPP;
 981
 982	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
 983
 984	return 0;
 985}
 986EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
 987
 988int usbnet_get_link_ksettings_internal(struct net_device *net,
 989					struct ethtool_link_ksettings *cmd)
 990{
 991	struct usbnet *dev = netdev_priv(net);
 992
 993	/* the assumption that speed is equal on tx and rx
 994	 * is deeply engrained into the networking layer.
 995	 * For wireless stuff it is not true.
 996	 * We assume that rx_speed matters more.
 997	 */
 998	if (dev->rx_speed != SPEED_UNSET)
 999		cmd->base.speed = dev->rx_speed / 1000000;
1000	else if (dev->tx_speed != SPEED_UNSET)
1001		cmd->base.speed = dev->tx_speed / 1000000;
1002	else
1003		cmd->base.speed = SPEED_UNKNOWN;
1004
1005	return 0;
1006}
1007EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
1008
1009int usbnet_set_link_ksettings_mii(struct net_device *net,
1010			      const struct ethtool_link_ksettings *cmd)
1011{
1012	struct usbnet *dev = netdev_priv(net);
1013	int retval;
1014
1015	if (!dev->mii.mdio_write)
1016		return -EOPNOTSUPP;
1017
1018	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1019
1020	/* link speed/duplex might have changed */
1021	if (dev->driver_info->link_reset)
1022		dev->driver_info->link_reset(dev);
1023
1024	/* hard_mtu or rx_urb_size may change in link_reset() */
1025	usbnet_update_max_qlen(dev);
1026
1027	return retval;
1028}
1029EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1030
1031u32 usbnet_get_link (struct net_device *net)
1032{
1033	struct usbnet *dev = netdev_priv(net);
1034
1035	/* If a check_connect is defined, return its result */
1036	if (dev->driver_info->check_connect)
1037		return dev->driver_info->check_connect (dev) == 0;
1038
1039	/* if the device has mii operations, use those */
1040	if (dev->mii.mdio_read)
1041		return mii_link_ok(&dev->mii);
1042
1043	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1044	return ethtool_op_get_link(net);
1045}
1046EXPORT_SYMBOL_GPL(usbnet_get_link);
1047
1048int usbnet_nway_reset(struct net_device *net)
1049{
1050	struct usbnet *dev = netdev_priv(net);
1051
1052	if (!dev->mii.mdio_write)
1053		return -EOPNOTSUPP;
1054
1055	return mii_nway_restart(&dev->mii);
1056}
1057EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1058
1059void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1060{
1061	struct usbnet *dev = netdev_priv(net);
1062
1063	strscpy(info->driver, dev->driver_name, sizeof(info->driver));
1064	strscpy(info->fw_version, dev->driver_info->description,
1065		sizeof(info->fw_version));
1066	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1067}
1068EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1069
1070u32 usbnet_get_msglevel (struct net_device *net)
1071{
1072	struct usbnet *dev = netdev_priv(net);
1073
1074	return dev->msg_enable;
1075}
1076EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1077
1078void usbnet_set_msglevel (struct net_device *net, u32 level)
1079{
1080	struct usbnet *dev = netdev_priv(net);
1081
1082	dev->msg_enable = level;
1083}
1084EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1085
1086/* drivers may override default ethtool_ops in their bind() routine */
1087static const struct ethtool_ops usbnet_ethtool_ops = {
1088	.get_link		= usbnet_get_link,
1089	.nway_reset		= usbnet_nway_reset,
1090	.get_drvinfo		= usbnet_get_drvinfo,
1091	.get_msglevel		= usbnet_get_msglevel,
1092	.set_msglevel		= usbnet_set_msglevel,
1093	.get_ts_info		= ethtool_op_get_ts_info,
1094	.get_link_ksettings	= usbnet_get_link_ksettings_mii,
1095	.set_link_ksettings	= usbnet_set_link_ksettings_mii,
1096};
1097
1098/*-------------------------------------------------------------------------*/
1099
1100static void __handle_link_change(struct usbnet *dev)
1101{
1102	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1103		return;
1104
1105	if (!netif_carrier_ok(dev->net)) {
1106		/* kill URBs for reading packets to save bus bandwidth */
1107		unlink_urbs(dev, &dev->rxq);
1108
1109		/*
1110		 * tx_timeout will unlink URBs for sending packets and
1111		 * tx queue is stopped by netcore after link becomes off
1112		 */
1113	} else {
1114		/* submitting URBs for reading packets */
1115		tasklet_schedule(&dev->bh);
1116	}
1117
1118	/* hard_mtu or rx_urb_size may change during link change */
1119	usbnet_update_max_qlen(dev);
1120
1121	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1122}
1123
1124void usbnet_set_rx_mode(struct net_device *net)
1125{
1126	struct usbnet		*dev = netdev_priv(net);
1127
1128	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1129}
1130EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1131
1132static void __handle_set_rx_mode(struct usbnet *dev)
1133{
1134	if (dev->driver_info->set_rx_mode)
1135		(dev->driver_info->set_rx_mode)(dev);
1136
1137	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1138}
1139
1140/* work that cannot be done in interrupt context uses keventd.
1141 *
1142 * NOTE:  with 2.5 we could do more of this using completion callbacks,
1143 * especially now that control transfers can be queued.
1144 */
1145static void
1146usbnet_deferred_kevent (struct work_struct *work)
1147{
1148	struct usbnet		*dev =
1149		container_of(work, struct usbnet, kevent);
1150	int			status;
1151
1152	/* usb_clear_halt() needs a thread context */
1153	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1154		unlink_urbs (dev, &dev->txq);
1155		status = usb_autopm_get_interface(dev->intf);
1156		if (status < 0)
1157			goto fail_pipe;
1158		status = usb_clear_halt (dev->udev, dev->out);
1159		usb_autopm_put_interface(dev->intf);
1160		if (status < 0 &&
1161		    status != -EPIPE &&
1162		    status != -ESHUTDOWN) {
1163			if (netif_msg_tx_err (dev))
1164fail_pipe:
1165				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1166					   status);
1167		} else {
1168			clear_bit (EVENT_TX_HALT, &dev->flags);
1169			if (status != -ESHUTDOWN)
1170				netif_wake_queue (dev->net);
1171		}
1172	}
1173	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1174		unlink_urbs (dev, &dev->rxq);
1175		status = usb_autopm_get_interface(dev->intf);
1176		if (status < 0)
1177			goto fail_halt;
1178		status = usb_clear_halt (dev->udev, dev->in);
1179		usb_autopm_put_interface(dev->intf);
1180		if (status < 0 &&
1181		    status != -EPIPE &&
1182		    status != -ESHUTDOWN) {
1183			if (netif_msg_rx_err (dev))
1184fail_halt:
1185				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1186					   status);
1187		} else {
1188			clear_bit (EVENT_RX_HALT, &dev->flags);
1189			if (!usbnet_going_away(dev))
1190				tasklet_schedule(&dev->bh);
1191		}
1192	}
1193
1194	/* tasklet could resubmit itself forever if memory is tight */
1195	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1196		struct urb	*urb = NULL;
1197		int resched = 1;
1198
1199		if (netif_running (dev->net))
1200			urb = usb_alloc_urb (0, GFP_KERNEL);
1201		else
1202			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1203		if (urb != NULL) {
1204			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1205			status = usb_autopm_get_interface(dev->intf);
1206			if (status < 0) {
1207				usb_free_urb(urb);
1208				goto fail_lowmem;
1209			}
1210			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1211				resched = 0;
1212			usb_autopm_put_interface(dev->intf);
1213fail_lowmem:
1214			if (resched)
1215				if (!usbnet_going_away(dev))
1216					tasklet_schedule(&dev->bh);
1217		}
1218	}
1219
1220	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1221		const struct driver_info *info = dev->driver_info;
1222		int			retval = 0;
1223
1224		clear_bit (EVENT_LINK_RESET, &dev->flags);
1225		status = usb_autopm_get_interface(dev->intf);
1226		if (status < 0)
1227			goto skip_reset;
1228		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1229			usb_autopm_put_interface(dev->intf);
1230skip_reset:
1231			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1232				    retval,
1233				    dev->udev->bus->bus_name,
1234				    dev->udev->devpath,
1235				    info->description);
1236		} else {
1237			usb_autopm_put_interface(dev->intf);
1238		}
1239
1240		/* handle link change from link resetting */
1241		__handle_link_change(dev);
1242	}
1243
1244	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1245		__handle_link_change(dev);
1246
1247	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1248		__handle_set_rx_mode(dev);
1249
1250
1251	if (dev->flags)
1252		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1253}
1254
1255/*-------------------------------------------------------------------------*/
1256
1257static void tx_complete (struct urb *urb)
1258{
1259	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1260	struct skb_data		*entry = (struct skb_data *) skb->cb;
1261	struct usbnet		*dev = entry->dev;
1262
1263	if (urb->status == 0) {
1264		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1265		unsigned long flags;
1266
1267		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1268		u64_stats_add(&stats64->tx_packets, entry->packets);
1269		u64_stats_add(&stats64->tx_bytes, entry->length);
1270		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1271	} else {
1272		dev->net->stats.tx_errors++;
1273
1274		switch (urb->status) {
1275		case -EPIPE:
1276			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1277			break;
1278
1279		/* software-driven interface shutdown */
1280		case -ECONNRESET:		// async unlink
1281		case -ESHUTDOWN:		// hardware gone
1282			break;
1283
1284		/* like rx, tx gets controller i/o faults during hub_wq
1285		 * delays and so it uses the same throttling mechanism.
1286		 */
1287		case -EPROTO:
1288		case -ETIME:
1289		case -EILSEQ:
1290			usb_mark_last_busy(dev->udev);
1291			if (!timer_pending (&dev->delay)) {
1292				mod_timer (&dev->delay,
1293					jiffies + THROTTLE_JIFFIES);
1294				netif_dbg(dev, link, dev->net,
1295					  "tx throttle %d\n", urb->status);
1296			}
1297			netif_stop_queue (dev->net);
1298			break;
1299		default:
1300			netif_dbg(dev, tx_err, dev->net,
1301				  "tx err %d\n", entry->urb->status);
1302			break;
1303		}
1304	}
1305
1306	usb_autopm_put_interface_async(dev->intf);
1307	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1308}
1309
1310/*-------------------------------------------------------------------------*/
1311
1312void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1313{
1314	struct usbnet		*dev = netdev_priv(net);
1315
1316	unlink_urbs (dev, &dev->txq);
1317	tasklet_schedule (&dev->bh);
1318	/* this needs to be handled individually because the generic layer
1319	 * doesn't know what is sufficient and could not restore private
1320	 * information if a remedy of an unconditional reset were used.
1321	 */
1322	if (dev->driver_info->recover)
1323		(dev->driver_info->recover)(dev);
1324}
1325EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1326
1327/*-------------------------------------------------------------------------*/
1328
1329static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1330{
1331	unsigned num_sgs, total_len = 0;
1332	int i, s = 0;
1333
1334	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1335	if (num_sgs == 1)
1336		return 0;
1337
1338	/* reserve one for zero packet */
1339	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1340				GFP_ATOMIC);
1341	if (!urb->sg)
1342		return -ENOMEM;
1343
1344	urb->num_sgs = num_sgs;
1345	sg_init_table(urb->sg, urb->num_sgs + 1);
1346
1347	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1348	total_len += skb_headlen(skb);
1349
1350	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1351		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1352
1353		total_len += skb_frag_size(f);
1354		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1355			    skb_frag_off(f));
1356	}
1357	urb->transfer_buffer_length = total_len;
1358
1359	return 1;
1360}
1361
1362netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1363				     struct net_device *net)
1364{
1365	struct usbnet		*dev = netdev_priv(net);
1366	unsigned int			length;
1367	struct urb		*urb = NULL;
1368	struct skb_data		*entry;
1369	const struct driver_info *info = dev->driver_info;
1370	unsigned long		flags;
1371	int retval;
1372
1373	if (skb)
1374		skb_tx_timestamp(skb);
1375
1376	// some devices want funky USB-level framing, for
1377	// win32 driver (usually) and/or hardware quirks
1378	if (info->tx_fixup) {
1379		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1380		if (!skb) {
1381			/* packet collected; minidriver waiting for more */
1382			if (info->flags & FLAG_MULTI_PACKET)
1383				goto not_drop;
1384			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1385			goto drop;
1386		}
1387	}
1388
1389	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1390		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1391		goto drop;
1392	}
1393
1394	entry = (struct skb_data *) skb->cb;
1395	entry->urb = urb;
1396	entry->dev = dev;
1397
1398	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1399			skb->data, skb->len, tx_complete, skb);
1400	if (dev->can_dma_sg) {
1401		if (build_dma_sg(skb, urb) < 0)
1402			goto drop;
1403	}
1404	length = urb->transfer_buffer_length;
1405
1406	/* don't assume the hardware handles USB_ZERO_PACKET
1407	 * NOTE:  strictly conforming cdc-ether devices should expect
1408	 * the ZLP here, but ignore the one-byte packet.
1409	 * NOTE2: CDC NCM specification is different from CDC ECM when
1410	 * handling ZLP/short packets, so cdc_ncm driver will make short
1411	 * packet itself if needed.
1412	 */
1413	if (length % dev->maxpacket == 0) {
1414		if (!(info->flags & FLAG_SEND_ZLP)) {
1415			if (!(info->flags & FLAG_MULTI_PACKET)) {
1416				length++;
1417				if (skb_tailroom(skb) && !urb->num_sgs) {
1418					skb->data[skb->len] = 0;
1419					__skb_put(skb, 1);
1420				} else if (urb->num_sgs)
1421					sg_set_buf(&urb->sg[urb->num_sgs++],
1422							dev->padding_pkt, 1);
1423			}
1424		} else
1425			urb->transfer_flags |= URB_ZERO_PACKET;
1426	}
1427	urb->transfer_buffer_length = length;
1428
1429	if (info->flags & FLAG_MULTI_PACKET) {
1430		/* Driver has set number of packets and a length delta.
1431		 * Calculate the complete length and ensure that it's
1432		 * positive.
1433		 */
1434		entry->length += length;
1435		if (WARN_ON_ONCE(entry->length <= 0))
1436			entry->length = length;
1437	} else {
1438		usbnet_set_skb_tx_stats(skb, 1, length);
1439	}
1440
1441	spin_lock_irqsave(&dev->txq.lock, flags);
1442	retval = usb_autopm_get_interface_async(dev->intf);
1443	if (retval < 0) {
1444		spin_unlock_irqrestore(&dev->txq.lock, flags);
1445		goto drop;
1446	}
1447	if (netif_queue_stopped(net)) {
1448		usb_autopm_put_interface_async(dev->intf);
1449		spin_unlock_irqrestore(&dev->txq.lock, flags);
1450		goto drop;
1451	}
1452
1453#ifdef CONFIG_PM
1454	/* if this triggers the device is still a sleep */
1455	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1456		/* transmission will be done in resume */
1457		usb_anchor_urb(urb, &dev->deferred);
1458		/* no use to process more packets */
1459		netif_stop_queue(net);
1460		usb_put_urb(urb);
1461		spin_unlock_irqrestore(&dev->txq.lock, flags);
1462		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1463		goto deferred;
1464	}
1465#endif
1466
1467	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1468	case -EPIPE:
1469		netif_stop_queue (net);
1470		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1471		usb_autopm_put_interface_async(dev->intf);
1472		break;
1473	default:
1474		usb_autopm_put_interface_async(dev->intf);
1475		netif_dbg(dev, tx_err, dev->net,
1476			  "tx: submit urb err %d\n", retval);
1477		break;
1478	case 0:
1479		netif_trans_update(net);
1480		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1481		if (dev->txq.qlen >= TX_QLEN (dev))
1482			netif_stop_queue (net);
1483	}
1484	spin_unlock_irqrestore (&dev->txq.lock, flags);
1485
1486	if (retval) {
1487		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1488drop:
1489		dev->net->stats.tx_dropped++;
1490not_drop:
1491		if (skb)
1492			dev_kfree_skb_any (skb);
1493		if (urb) {
1494			kfree(urb->sg);
1495			usb_free_urb(urb);
1496		}
1497	} else
1498		netif_dbg(dev, tx_queued, dev->net,
1499			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1500#ifdef CONFIG_PM
1501deferred:
1502#endif
1503	return NETDEV_TX_OK;
1504}
1505EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1506
1507static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1508{
1509	struct urb	*urb;
1510	int		i;
1511	int		ret = 0;
1512
1513	/* don't refill the queue all at once */
1514	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1515		urb = usb_alloc_urb(0, flags);
1516		if (urb != NULL) {
1517			ret = rx_submit(dev, urb, flags);
1518			if (ret)
1519				goto err;
1520		} else {
1521			ret = -ENOMEM;
1522			goto err;
1523		}
1524	}
1525err:
1526	return ret;
1527}
1528
1529static inline void usb_free_skb(struct sk_buff *skb)
1530{
1531	struct skb_data *entry = (struct skb_data *)skb->cb;
1532
1533	usb_free_urb(entry->urb);
1534	dev_kfree_skb(skb);
1535}
1536
1537/*-------------------------------------------------------------------------*/
1538
1539// tasklet (work deferred from completions, in_irq) or timer
1540
1541static void usbnet_bh (struct timer_list *t)
1542{
1543	struct usbnet		*dev = from_timer(dev, t, delay);
1544	struct sk_buff		*skb;
1545	struct skb_data		*entry;
1546
1547	while ((skb = skb_dequeue (&dev->done))) {
1548		entry = (struct skb_data *) skb->cb;
1549		switch (entry->state) {
1550		case rx_done:
1551			if (rx_process(dev, skb))
1552				usb_free_skb(skb);
1553			continue;
1554		case tx_done:
1555			kfree(entry->urb->sg);
1556			fallthrough;
1557		case rx_cleanup:
1558			usb_free_skb(skb);
 
1559			continue;
1560		default:
1561			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1562		}
1563	}
1564
1565	/* restart RX again after disabling due to high error rate */
1566	clear_bit(EVENT_RX_KILL, &dev->flags);
1567
1568	/* waiting for all pending urbs to complete?
1569	 * only then can we forgo submitting anew
1570	 */
1571	if (waitqueue_active(&dev->wait)) {
1572		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1573			wake_up_all(&dev->wait);
1574
1575	// or are we maybe short a few urbs?
1576	} else if (netif_running (dev->net) &&
1577		   netif_device_present (dev->net) &&
1578		   netif_carrier_ok(dev->net) &&
1579		   !usbnet_going_away(dev) &&
1580		   !timer_pending(&dev->delay) &&
1581		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1582		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1583		int	temp = dev->rxq.qlen;
1584
1585		if (temp < RX_QLEN(dev)) {
1586			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1587				return;
1588			if (temp != dev->rxq.qlen)
1589				netif_dbg(dev, link, dev->net,
1590					  "rxqlen %d --> %d\n",
1591					  temp, dev->rxq.qlen);
1592			if (dev->rxq.qlen < RX_QLEN(dev))
1593				tasklet_schedule (&dev->bh);
1594		}
1595		if (dev->txq.qlen < TX_QLEN (dev))
1596			netif_wake_queue (dev->net);
1597	}
1598}
1599
1600static void usbnet_bh_tasklet(struct tasklet_struct *t)
1601{
1602	struct usbnet *dev = from_tasklet(dev, t, bh);
1603
1604	usbnet_bh(&dev->delay);
1605}
1606
1607
1608/*-------------------------------------------------------------------------
1609 *
1610 * USB Device Driver support
1611 *
1612 *-------------------------------------------------------------------------*/
1613
1614// precondition: never called in_interrupt
1615
1616void usbnet_disconnect (struct usb_interface *intf)
1617{
1618	struct usbnet		*dev;
1619	struct usb_device	*xdev;
1620	struct net_device	*net;
1621	struct urb		*urb;
1622
1623	dev = usb_get_intfdata(intf);
1624	usb_set_intfdata(intf, NULL);
1625	if (!dev)
1626		return;
1627	usbnet_mark_going_away(dev);
1628
1629	xdev = interface_to_usbdev (intf);
1630
1631	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1632		   intf->dev.driver->name,
1633		   xdev->bus->bus_name, xdev->devpath,
1634		   dev->driver_info->description);
1635
 
 
 
1636	net = dev->net;
1637	unregister_netdev (net);
1638
1639	while ((urb = usb_get_from_anchor(&dev->deferred))) {
1640		dev_kfree_skb(urb->context);
1641		kfree(urb->sg);
1642		usb_free_urb(urb);
1643	}
1644
1645	if (dev->driver_info->unbind)
1646		dev->driver_info->unbind(dev, intf);
1647
1648	usb_kill_urb(dev->interrupt);
1649	usb_free_urb(dev->interrupt);
1650	kfree(dev->padding_pkt);
1651
 
1652	free_netdev(net);
1653}
1654EXPORT_SYMBOL_GPL(usbnet_disconnect);
1655
1656static const struct net_device_ops usbnet_netdev_ops = {
1657	.ndo_open		= usbnet_open,
1658	.ndo_stop		= usbnet_stop,
1659	.ndo_start_xmit		= usbnet_start_xmit,
1660	.ndo_tx_timeout		= usbnet_tx_timeout,
1661	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1662	.ndo_change_mtu		= usbnet_change_mtu,
 
1663	.ndo_set_mac_address 	= eth_mac_addr,
1664	.ndo_validate_addr	= eth_validate_addr,
1665};
1666
1667/*-------------------------------------------------------------------------*/
1668
1669// precondition: never called in_interrupt
1670
1671static const struct device_type wlan_type = {
1672	.name	= "wlan",
1673};
1674
1675static const struct device_type wwan_type = {
1676	.name	= "wwan",
1677};
1678
1679int
1680usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1681{
1682	struct usbnet			*dev;
1683	struct net_device		*net;
1684	struct usb_host_interface	*interface;
1685	const struct driver_info	*info;
1686	struct usb_device		*xdev;
1687	int				status;
1688	const char			*name;
1689	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1690
1691	/* usbnet already took usb runtime pm, so have to enable the feature
1692	 * for usb interface, otherwise usb_autopm_get_interface may return
1693	 * failure if RUNTIME_PM is enabled.
1694	 */
1695	if (!driver->supports_autosuspend) {
1696		driver->supports_autosuspend = 1;
1697		pm_runtime_enable(&udev->dev);
1698	}
1699
1700	name = udev->dev.driver->name;
1701	info = (const struct driver_info *) prod->driver_info;
1702	if (!info) {
1703		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1704		return -ENODEV;
1705	}
1706	xdev = interface_to_usbdev (udev);
1707	interface = udev->cur_altsetting;
1708
1709	status = -ENOMEM;
1710
1711	// set up our own records
1712	net = alloc_etherdev(sizeof(*dev));
1713	if (!net)
1714		goto out;
1715
1716	/* netdev_printk() needs this so do it as early as possible */
1717	SET_NETDEV_DEV(net, &udev->dev);
1718
1719	dev = netdev_priv(net);
1720	dev->udev = xdev;
1721	dev->intf = udev;
1722	dev->driver_info = info;
1723	dev->driver_name = name;
1724	dev->rx_speed = SPEED_UNSET;
1725	dev->tx_speed = SPEED_UNSET;
1726
 
 
 
 
1727	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1728				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1729	init_waitqueue_head(&dev->wait);
1730	skb_queue_head_init (&dev->rxq);
1731	skb_queue_head_init (&dev->txq);
1732	skb_queue_head_init (&dev->done);
1733	skb_queue_head_init(&dev->rxq_pause);
1734	tasklet_setup(&dev->bh, usbnet_bh_tasklet);
1735	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1736	init_usb_anchor(&dev->deferred);
1737	timer_setup(&dev->delay, usbnet_bh, 0);
1738	mutex_init (&dev->phy_mutex);
1739	mutex_init(&dev->interrupt_mutex);
1740	dev->interrupt_count = 0;
1741
1742	dev->net = net;
1743	strscpy(net->name, "usb%d", sizeof(net->name));
 
1744
1745	/* rx and tx sides can use different message sizes;
1746	 * bind() should set rx_urb_size in that case.
1747	 */
1748	dev->hard_mtu = net->mtu + net->hard_header_len;
1749	net->min_mtu = 0;
1750	net->max_mtu = ETH_MAX_MTU;
1751	net->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1752
1753	net->netdev_ops = &usbnet_netdev_ops;
1754	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1755	net->ethtool_ops = &usbnet_ethtool_ops;
1756	net->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1757
1758	// allow device-specific bind/init procedures
1759	// NOTE net->name still not usable ...
1760	if (info->bind) {
1761		status = info->bind (dev, udev);
1762		if (status < 0)
1763			goto out1;
1764
1765		// heuristic:  "usb%d" for links we know are two-host,
1766		// else "eth%d" when there's reasonable doubt.  userspace
1767		// can rename the link if it knows better.
1768		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1769		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1770		     /* somebody touched it*/
1771		     !is_zero_ether_addr(net->dev_addr)))
1772			strscpy(net->name, "eth%d", sizeof(net->name));
1773		/* WLAN devices should always be named "wlan%d" */
1774		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1775			strscpy(net->name, "wlan%d", sizeof(net->name));
1776		/* WWAN devices should always be named "wwan%d" */
1777		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1778			strscpy(net->name, "wwan%d", sizeof(net->name));
1779
1780		/* devices that cannot do ARP */
1781		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1782			net->flags |= IFF_NOARP;
1783
1784		/* maybe the remote can't receive an Ethernet MTU */
1785		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1786			net->mtu = dev->hard_mtu - net->hard_header_len;
1787	} else if (!info->in || !info->out)
1788		status = usbnet_get_endpoints (dev, udev);
1789	else {
1790		u8 ep_addrs[3] = {
1791			info->in + USB_DIR_IN, info->out + USB_DIR_OUT, 0
1792		};
1793
1794		dev->in = usb_rcvbulkpipe (xdev, info->in);
1795		dev->out = usb_sndbulkpipe (xdev, info->out);
1796		if (!(info->flags & FLAG_NO_SETINT))
1797			status = usb_set_interface (xdev,
1798				interface->desc.bInterfaceNumber,
1799				interface->desc.bAlternateSetting);
1800		else
1801			status = 0;
1802
1803		if (status == 0 && !usb_check_bulk_endpoints(udev, ep_addrs))
1804			status = -EINVAL;
1805	}
1806	if (status >= 0 && dev->status)
1807		status = init_status (dev, udev);
1808	if (status < 0)
1809		goto out3;
1810
1811	if (!dev->rx_urb_size)
1812		dev->rx_urb_size = dev->hard_mtu;
1813	dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
1814	if (dev->maxpacket == 0) {
1815		/* that is a broken device */
1816		status = -ENODEV;
1817		goto out4;
1818	}
1819
1820	/* this flags the device for user space */
1821	if (!is_valid_ether_addr(net->dev_addr))
1822		eth_hw_addr_random(net);
1823
1824	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1825		SET_NETDEV_DEVTYPE(net, &wlan_type);
1826	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1827		SET_NETDEV_DEVTYPE(net, &wwan_type);
1828
1829	/* initialize max rx_qlen and tx_qlen */
1830	usbnet_update_max_qlen(dev);
1831
1832	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1833		!(info->flags & FLAG_MULTI_PACKET)) {
1834		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1835		if (!dev->padding_pkt) {
1836			status = -ENOMEM;
1837			goto out4;
1838		}
1839	}
1840
1841	status = register_netdev (net);
1842	if (status)
1843		goto out5;
1844	netif_info(dev, probe, dev->net,
1845		   "register '%s' at usb-%s-%s, %s, %pM\n",
1846		   udev->dev.driver->name,
1847		   xdev->bus->bus_name, xdev->devpath,
1848		   dev->driver_info->description,
1849		   net->dev_addr);
1850
1851	// ok, it's ready to go.
1852	usb_set_intfdata (udev, dev);
1853
1854	netif_device_attach (net);
1855
1856	if (dev->driver_info->flags & FLAG_LINK_INTR)
1857		usbnet_link_change(dev, 0, 0);
1858
1859	return 0;
1860
1861out5:
1862	kfree(dev->padding_pkt);
1863out4:
1864	usb_free_urb(dev->interrupt);
1865out3:
1866	if (info->unbind)
1867		info->unbind (dev, udev);
1868out1:
1869	/* subdrivers must undo all they did in bind() if they
1870	 * fail it, but we may fail later and a deferred kevent
1871	 * may trigger an error resubmitting itself and, worse,
1872	 * schedule a timer. So we kill it all just in case.
1873	 */
1874	usbnet_mark_going_away(dev);
1875	cancel_work_sync(&dev->kevent);
1876	del_timer_sync(&dev->delay);
 
 
1877	free_netdev(net);
1878out:
1879	return status;
1880}
1881EXPORT_SYMBOL_GPL(usbnet_probe);
1882
1883/*-------------------------------------------------------------------------*/
1884
1885/*
1886 * suspend the whole driver as soon as the first interface is suspended
1887 * resume only when the last interface is resumed
1888 */
1889
1890int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1891{
1892	struct usbnet		*dev = usb_get_intfdata(intf);
1893
1894	if (!dev->suspend_count++) {
1895		spin_lock_irq(&dev->txq.lock);
1896		/* don't autosuspend while transmitting */
1897		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1898			dev->suspend_count--;
1899			spin_unlock_irq(&dev->txq.lock);
1900			return -EBUSY;
1901		} else {
1902			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1903			spin_unlock_irq(&dev->txq.lock);
1904		}
1905		/*
1906		 * accelerate emptying of the rx and queues, to avoid
1907		 * having everything error out.
1908		 */
1909		netif_device_detach (dev->net);
1910		usbnet_terminate_urbs(dev);
1911		__usbnet_status_stop_force(dev);
1912
1913		/*
1914		 * reattach so runtime management can use and
1915		 * wake the device
1916		 */
1917		netif_device_attach (dev->net);
1918	}
1919	return 0;
1920}
1921EXPORT_SYMBOL_GPL(usbnet_suspend);
1922
1923int usbnet_resume (struct usb_interface *intf)
1924{
1925	struct usbnet		*dev = usb_get_intfdata(intf);
1926	struct sk_buff          *skb;
1927	struct urb              *res;
1928	int                     retval;
1929
1930	if (!--dev->suspend_count) {
1931		/* resume interrupt URB if it was previously submitted */
1932		__usbnet_status_start_force(dev, GFP_NOIO);
1933
1934		spin_lock_irq(&dev->txq.lock);
1935		while ((res = usb_get_from_anchor(&dev->deferred))) {
1936
1937			skb = (struct sk_buff *)res->context;
1938			retval = usb_submit_urb(res, GFP_ATOMIC);
1939			if (retval < 0) {
1940				dev_kfree_skb_any(skb);
1941				kfree(res->sg);
1942				usb_free_urb(res);
1943				usb_autopm_put_interface_async(dev->intf);
1944			} else {
1945				netif_trans_update(dev->net);
1946				__skb_queue_tail(&dev->txq, skb);
1947			}
1948		}
1949
1950		smp_mb();
1951		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1952		spin_unlock_irq(&dev->txq.lock);
1953
1954		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1955			/* handle remote wakeup ASAP
1956			 * we cannot race against stop
1957			 */
1958			if (netif_device_present(dev->net) &&
1959				!timer_pending(&dev->delay) &&
1960				!test_bit(EVENT_RX_HALT, &dev->flags))
1961					rx_alloc_submit(dev, GFP_NOIO);
1962
1963			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1964				netif_tx_wake_all_queues(dev->net);
1965			tasklet_schedule (&dev->bh);
1966		}
1967	}
1968
1969	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1970		usb_autopm_get_interface_no_resume(intf);
1971
1972	return 0;
1973}
1974EXPORT_SYMBOL_GPL(usbnet_resume);
1975
1976/*
1977 * Either a subdriver implements manage_power, then it is assumed to always
1978 * be ready to be suspended or it reports the readiness to be suspended
1979 * explicitly
1980 */
1981void usbnet_device_suggests_idle(struct usbnet *dev)
1982{
1983	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1984		dev->intf->needs_remote_wakeup = 1;
1985		usb_autopm_put_interface_async(dev->intf);
1986	}
1987}
1988EXPORT_SYMBOL(usbnet_device_suggests_idle);
1989
1990/*
1991 * For devices that can do without special commands
1992 */
1993int usbnet_manage_power(struct usbnet *dev, int on)
1994{
1995	dev->intf->needs_remote_wakeup = on;
1996	return 0;
1997}
1998EXPORT_SYMBOL(usbnet_manage_power);
1999
2000void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
2001{
2002	/* update link after link is reseted */
2003	if (link && !need_reset)
2004		netif_carrier_on(dev->net);
2005	else
2006		netif_carrier_off(dev->net);
2007
2008	if (need_reset && link)
2009		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
2010	else
2011		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
2012}
2013EXPORT_SYMBOL(usbnet_link_change);
2014
2015/*-------------------------------------------------------------------------*/
2016static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2017			     u16 value, u16 index, void *data, u16 size)
2018{
2019	void *buf = NULL;
2020	int err = -ENOMEM;
2021
2022	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
2023		   " value=0x%04x index=0x%04x size=%d\n",
2024		   cmd, reqtype, value, index, size);
2025
2026	if (size) {
2027		buf = kmalloc(size, GFP_NOIO);
2028		if (!buf)
2029			goto out;
2030	}
2031
2032	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2033			      cmd, reqtype, value, index, buf, size,
2034			      USB_CTRL_GET_TIMEOUT);
2035	if (err > 0 && err <= size) {
2036		if (data)
2037			memcpy(data, buf, err);
2038		else
2039			netdev_dbg(dev->net,
2040				   "Huh? Data requested but thrown away.\n");
2041	}
2042	kfree(buf);
2043out:
2044	return err;
2045}
2046
2047static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2048			      u16 value, u16 index, const void *data,
2049			      u16 size)
2050{
2051	void *buf = NULL;
2052	int err = -ENOMEM;
2053
2054	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2055		   " value=0x%04x index=0x%04x size=%d\n",
2056		   cmd, reqtype, value, index, size);
2057
2058	if (data) {
2059		buf = kmemdup(data, size, GFP_NOIO);
2060		if (!buf)
2061			goto out;
2062	} else {
2063        if (size) {
2064            WARN_ON_ONCE(1);
2065            err = -EINVAL;
2066            goto out;
2067        }
2068    }
2069
2070	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2071			      cmd, reqtype, value, index, buf, size,
2072			      USB_CTRL_SET_TIMEOUT);
2073	kfree(buf);
2074
2075out:
2076	return err;
2077}
2078
2079/*
2080 * The function can't be called inside suspend/resume callback,
2081 * otherwise deadlock will be caused.
2082 */
2083int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2084		    u16 value, u16 index, void *data, u16 size)
2085{
2086	int ret;
2087
2088	if (usb_autopm_get_interface(dev->intf) < 0)
2089		return -ENODEV;
2090	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2091				data, size);
2092	usb_autopm_put_interface(dev->intf);
2093	return ret;
2094}
2095EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2096
2097/*
2098 * The function can't be called inside suspend/resume callback,
2099 * otherwise deadlock will be caused.
2100 */
2101int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2102		     u16 value, u16 index, const void *data, u16 size)
2103{
2104	int ret;
2105
2106	if (usb_autopm_get_interface(dev->intf) < 0)
2107		return -ENODEV;
2108	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2109				 data, size);
2110	usb_autopm_put_interface(dev->intf);
2111	return ret;
2112}
2113EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2114
2115/*
2116 * The function can be called inside suspend/resume callback safely
2117 * and should only be called by suspend/resume callback generally.
2118 */
2119int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2120			  u16 value, u16 index, void *data, u16 size)
2121{
2122	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2123				 data, size);
2124}
2125EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2126
2127/*
2128 * The function can be called inside suspend/resume callback safely
2129 * and should only be called by suspend/resume callback generally.
2130 */
2131int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2132			  u16 value, u16 index, const void *data,
2133			  u16 size)
2134{
2135	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2136				  data, size);
2137}
2138EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2139
2140static void usbnet_async_cmd_cb(struct urb *urb)
2141{
2142	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2143	int status = urb->status;
2144
2145	if (status < 0)
2146		dev_dbg(&urb->dev->dev, "%s failed with %d",
2147			__func__, status);
2148
2149	kfree(req);
2150	usb_free_urb(urb);
2151}
2152
2153/*
2154 * The caller must make sure that device can't be put into suspend
2155 * state until the control URB completes.
2156 */
2157int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2158			   u16 value, u16 index, const void *data, u16 size)
2159{
2160	struct usb_ctrlrequest *req;
2161	struct urb *urb;
2162	int err = -ENOMEM;
2163	void *buf = NULL;
2164
2165	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2166		   " value=0x%04x index=0x%04x size=%d\n",
2167		   cmd, reqtype, value, index, size);
2168
2169	urb = usb_alloc_urb(0, GFP_ATOMIC);
2170	if (!urb)
2171		goto fail;
2172
2173	if (data) {
2174		buf = kmemdup(data, size, GFP_ATOMIC);
2175		if (!buf) {
2176			netdev_err(dev->net, "Error allocating buffer"
2177				   " in %s!\n", __func__);
2178			goto fail_free_urb;
2179		}
2180	}
2181
2182	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2183	if (!req)
2184		goto fail_free_buf;
2185
2186	req->bRequestType = reqtype;
2187	req->bRequest = cmd;
2188	req->wValue = cpu_to_le16(value);
2189	req->wIndex = cpu_to_le16(index);
2190	req->wLength = cpu_to_le16(size);
2191
2192	usb_fill_control_urb(urb, dev->udev,
2193			     usb_sndctrlpipe(dev->udev, 0),
2194			     (void *)req, buf, size,
2195			     usbnet_async_cmd_cb, req);
2196	urb->transfer_flags |= URB_FREE_BUFFER;
2197
2198	err = usb_submit_urb(urb, GFP_ATOMIC);
2199	if (err < 0) {
2200		netdev_err(dev->net, "Error submitting the control"
2201			   " message: status=%d\n", err);
2202		goto fail_free_all;
2203	}
2204	return 0;
2205
2206fail_free_all:
2207	kfree(req);
2208fail_free_buf:
2209	kfree(buf);
2210	/*
2211	 * avoid a double free
2212	 * needed because the flag can be set only
2213	 * after filling the URB
2214	 */
2215	urb->transfer_flags = 0;
2216fail_free_urb:
2217	usb_free_urb(urb);
2218fail:
2219	return err;
2220
2221}
2222EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2223/*-------------------------------------------------------------------------*/
2224
2225static int __init usbnet_init(void)
2226{
2227	/* Compiler should optimize this out. */
2228	BUILD_BUG_ON(
2229		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2230
 
2231	return 0;
2232}
2233module_init(usbnet_init);
2234
2235static void __exit usbnet_exit(void)
2236{
2237}
2238module_exit(usbnet_exit);
2239
2240MODULE_AUTHOR("David Brownell");
2241MODULE_DESCRIPTION("USB network driver framework");
2242MODULE_LICENSE("GPL");