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// randomly generated ethernet address
  65static u8	node_id [ETH_ALEN];
  66
  67/* use ethtool to change the level for any given device */
  68static int msg_level = -1;
  69module_param (msg_level, int, 0);
  70MODULE_PARM_DESC (msg_level, "Override default message level");
  71
  72/*-------------------------------------------------------------------------*/
  73
  74static const char * const usbnet_event_names[] = {
  75	[EVENT_TX_HALT]		   = "EVENT_TX_HALT",
  76	[EVENT_RX_HALT]		   = "EVENT_RX_HALT",
  77	[EVENT_RX_MEMORY]	   = "EVENT_RX_MEMORY",
  78	[EVENT_STS_SPLIT]	   = "EVENT_STS_SPLIT",
  79	[EVENT_LINK_RESET]	   = "EVENT_LINK_RESET",
  80	[EVENT_RX_PAUSED]	   = "EVENT_RX_PAUSED",
  81	[EVENT_DEV_ASLEEP]	   = "EVENT_DEV_ASLEEP",
  82	[EVENT_DEV_OPEN]	   = "EVENT_DEV_OPEN",
  83	[EVENT_DEVICE_REPORT_IDLE] = "EVENT_DEVICE_REPORT_IDLE",
  84	[EVENT_NO_RUNTIME_PM]	   = "EVENT_NO_RUNTIME_PM",
  85	[EVENT_RX_KILL]		   = "EVENT_RX_KILL",
  86	[EVENT_LINK_CHANGE]	   = "EVENT_LINK_CHANGE",
  87	[EVENT_SET_RX_MODE]	   = "EVENT_SET_RX_MODE",
  88	[EVENT_NO_IP_ALIGN]	   = "EVENT_NO_IP_ALIGN",
  89};
  90
  91/* handles CDC Ethernet and many other network "bulk data" interfaces */
  92int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
  93{
  94	int				tmp;
  95	struct usb_host_interface	*alt = NULL;
  96	struct usb_host_endpoint	*in = NULL, *out = NULL;
  97	struct usb_host_endpoint	*status = NULL;
  98
  99	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
 100		unsigned	ep;
 101
 102		in = out = status = NULL;
 103		alt = intf->altsetting + tmp;
 104
 105		/* take the first altsetting with in-bulk + out-bulk;
 106		 * remember any status endpoint, just in case;
 107		 * ignore other endpoints and altsettings.
 108		 */
 109		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
 110			struct usb_host_endpoint	*e;
 111			int				intr = 0;
 112
 113			e = alt->endpoint + ep;
 114
 115			/* ignore endpoints which cannot transfer data */
 116			if (!usb_endpoint_maxp(&e->desc))
 117				continue;
 118
 119			switch (e->desc.bmAttributes) {
 120			case USB_ENDPOINT_XFER_INT:
 121				if (!usb_endpoint_dir_in(&e->desc))
 122					continue;
 123				intr = 1;
 124				fallthrough;
 125			case USB_ENDPOINT_XFER_BULK:
 126				break;
 127			default:
 128				continue;
 129			}
 130			if (usb_endpoint_dir_in(&e->desc)) {
 131				if (!intr && !in)
 132					in = e;
 133				else if (intr && !status)
 134					status = e;
 135			} else {
 136				if (!out)
 137					out = e;
 138			}
 139		}
 140		if (in && out)
 141			break;
 142	}
 143	if (!alt || !in || !out)
 144		return -EINVAL;
 145
 146	if (alt->desc.bAlternateSetting != 0 ||
 147	    !(dev->driver_info->flags & FLAG_NO_SETINT)) {
 148		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
 149				alt->desc.bAlternateSetting);
 150		if (tmp < 0)
 151			return tmp;
 152	}
 153
 154	dev->in = usb_rcvbulkpipe (dev->udev,
 155			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 156	dev->out = usb_sndbulkpipe (dev->udev,
 157			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 158	dev->status = status;
 159	return 0;
 160}
 161EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
 162
 163int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
 164{
 165	u8		addr[ETH_ALEN];
 166	int 		tmp = -1, ret;
 167	unsigned char	buf [13];
 168
 169	ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
 170	if (ret == 12)
 171		tmp = hex2bin(addr, buf, 6);
 172	if (tmp < 0) {
 173		dev_dbg(&dev->udev->dev,
 174			"bad MAC string %d fetch, %d\n", iMACAddress, tmp);
 175		if (ret >= 0)
 176			ret = -EINVAL;
 177		return ret;
 178	}
 179	eth_hw_addr_set(dev->net, addr);
 180	return 0;
 181}
 182EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
 183
 184static void intr_complete (struct urb *urb)
 185{
 186	struct usbnet	*dev = urb->context;
 187	int		status = urb->status;
 188
 189	switch (status) {
 190	/* success */
 191	case 0:
 192		dev->driver_info->status(dev, urb);
 193		break;
 194
 195	/* software-driven interface shutdown */
 196	case -ENOENT:		/* urb killed */
 197	case -ESHUTDOWN:	/* hardware gone */
 198		netif_dbg(dev, ifdown, dev->net,
 199			  "intr shutdown, code %d\n", status);
 200		return;
 201
 202	/* NOTE:  not throttling like RX/TX, since this endpoint
 203	 * already polls infrequently
 204	 */
 205	default:
 206		netdev_dbg(dev->net, "intr status %d\n", status);
 207		break;
 208	}
 209
 210	status = usb_submit_urb (urb, GFP_ATOMIC);
 211	if (status != 0)
 212		netif_err(dev, timer, dev->net,
 213			  "intr resubmit --> %d\n", status);
 214}
 215
 216static int init_status (struct usbnet *dev, struct usb_interface *intf)
 217{
 218	char		*buf = NULL;
 219	unsigned	pipe = 0;
 220	unsigned	maxp;
 221	unsigned	period;
 222
 223	if (!dev->driver_info->status)
 224		return 0;
 225
 226	pipe = usb_rcvintpipe (dev->udev,
 227			dev->status->desc.bEndpointAddress
 228				& USB_ENDPOINT_NUMBER_MASK);
 229	maxp = usb_maxpacket(dev->udev, pipe);
 230
 231	/* avoid 1 msec chatter:  min 8 msec poll rate */
 232	period = max ((int) dev->status->desc.bInterval,
 233		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
 234
 235	buf = kmalloc (maxp, GFP_KERNEL);
 236	if (buf) {
 237		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
 238		if (!dev->interrupt) {
 239			kfree (buf);
 240			return -ENOMEM;
 241		} else {
 242			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
 243				buf, maxp, intr_complete, dev, period);
 244			dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
 245			dev_dbg(&intf->dev,
 246				"status ep%din, %d bytes period %d\n",
 247				usb_pipeendpoint(pipe), maxp, period);
 248		}
 249	}
 250	return 0;
 251}
 252
 253/* Submit the interrupt URB if not previously submitted, increasing refcount */
 254int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
 255{
 256	int ret = 0;
 257
 258	WARN_ON_ONCE(dev->interrupt == NULL);
 259	if (dev->interrupt) {
 260		mutex_lock(&dev->interrupt_mutex);
 261
 262		if (++dev->interrupt_count == 1)
 263			ret = usb_submit_urb(dev->interrupt, mem_flags);
 264
 265		dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
 266			dev->interrupt_count);
 267		mutex_unlock(&dev->interrupt_mutex);
 268	}
 269	return ret;
 270}
 271EXPORT_SYMBOL_GPL(usbnet_status_start);
 272
 273/* For resume; submit interrupt URB if previously submitted */
 274static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
 275{
 276	int ret = 0;
 277
 278	mutex_lock(&dev->interrupt_mutex);
 279	if (dev->interrupt_count) {
 280		ret = usb_submit_urb(dev->interrupt, mem_flags);
 281		dev_dbg(&dev->udev->dev,
 282			"submitted interrupt URB for resume\n");
 283	}
 284	mutex_unlock(&dev->interrupt_mutex);
 285	return ret;
 286}
 287
 288/* Kill the interrupt URB if all submitters want it killed */
 289void usbnet_status_stop(struct usbnet *dev)
 290{
 291	if (dev->interrupt) {
 292		mutex_lock(&dev->interrupt_mutex);
 293		WARN_ON(dev->interrupt_count == 0);
 294
 295		if (dev->interrupt_count && --dev->interrupt_count == 0)
 296			usb_kill_urb(dev->interrupt);
 297
 298		dev_dbg(&dev->udev->dev,
 299			"decremented interrupt URB count to %d\n",
 300			dev->interrupt_count);
 301		mutex_unlock(&dev->interrupt_mutex);
 302	}
 303}
 304EXPORT_SYMBOL_GPL(usbnet_status_stop);
 305
 306/* For suspend; always kill interrupt URB */
 307static void __usbnet_status_stop_force(struct usbnet *dev)
 308{
 309	if (dev->interrupt) {
 310		mutex_lock(&dev->interrupt_mutex);
 311		usb_kill_urb(dev->interrupt);
 312		dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
 313		mutex_unlock(&dev->interrupt_mutex);
 314	}
 315}
 316
 317/* Passes this packet up the stack, updating its accounting.
 318 * Some link protocols batch packets, so their rx_fixup paths
 319 * can return clones as well as just modify the original skb.
 320 */
 321void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 322{
 323	struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
 324	unsigned long flags;
 325	int	status;
 326
 327	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
 328		skb_queue_tail(&dev->rxq_pause, skb);
 329		return;
 330	}
 331
 332	/* only update if unset to allow minidriver rx_fixup override */
 333	if (skb->protocol == 0)
 334		skb->protocol = eth_type_trans (skb, dev->net);
 335
 336	flags = u64_stats_update_begin_irqsave(&stats64->syncp);
 337	u64_stats_inc(&stats64->rx_packets);
 338	u64_stats_add(&stats64->rx_bytes, skb->len);
 339	u64_stats_update_end_irqrestore(&stats64->syncp, flags);
 340
 341	netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
 342		  skb->len + sizeof (struct ethhdr), skb->protocol);
 343	memset (skb->cb, 0, sizeof (struct skb_data));
 344
 345	if (skb_defer_rx_timestamp(skb))
 346		return;
 347
 348	status = netif_rx (skb);
 349	if (status != NET_RX_SUCCESS)
 350		netif_dbg(dev, rx_err, dev->net,
 351			  "netif_rx status %d\n", status);
 352}
 353EXPORT_SYMBOL_GPL(usbnet_skb_return);
 354
 355/* must be called if hard_mtu or rx_urb_size changed */
 356void usbnet_update_max_qlen(struct usbnet *dev)
 357{
 358	enum usb_device_speed speed = dev->udev->speed;
 359
 360	if (!dev->rx_urb_size || !dev->hard_mtu)
 361		goto insanity;
 362	switch (speed) {
 363	case USB_SPEED_HIGH:
 364		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
 365		dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
 366		break;
 367	case USB_SPEED_SUPER:
 368	case USB_SPEED_SUPER_PLUS:
 369		/*
 370		 * Not take default 5ms qlen for super speed HC to
 371		 * save memory, and iperf tests show 2.5ms qlen can
 372		 * work well
 373		 */
 374		dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
 375		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
 376		break;
 377	default:
 378insanity:
 379		dev->rx_qlen = dev->tx_qlen = 4;
 380	}
 381}
 382EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
 383
 384
 385/*-------------------------------------------------------------------------
 386 *
 387 * Network Device Driver (peer link to "Host Device", from USB host)
 388 *
 389 *-------------------------------------------------------------------------*/
 390
 391int usbnet_change_mtu (struct net_device *net, int new_mtu)
 392{
 393	struct usbnet	*dev = netdev_priv(net);
 394	int		ll_mtu = new_mtu + net->hard_header_len;
 395	int		old_hard_mtu = dev->hard_mtu;
 396	int		old_rx_urb_size = dev->rx_urb_size;
 397
 398	// no second zero-length packet read wanted after mtu-sized packets
 399	if ((ll_mtu % dev->maxpacket) == 0)
 400		return -EDOM;
 401	net->mtu = new_mtu;
 402
 403	dev->hard_mtu = net->mtu + net->hard_header_len;
 404	if (dev->rx_urb_size == old_hard_mtu) {
 405		dev->rx_urb_size = dev->hard_mtu;
 406		if (dev->rx_urb_size > old_rx_urb_size) {
 407			usbnet_pause_rx(dev);
 408			usbnet_unlink_rx_urbs(dev);
 409			usbnet_resume_rx(dev);
 410		}
 411	}
 412
 413	/* max qlen depend on hard_mtu and rx_urb_size */
 414	usbnet_update_max_qlen(dev);
 415
 416	return 0;
 417}
 418EXPORT_SYMBOL_GPL(usbnet_change_mtu);
 419
 420/* The caller must hold list->lock */
 421static void __usbnet_queue_skb(struct sk_buff_head *list,
 422			struct sk_buff *newsk, enum skb_state state)
 423{
 424	struct skb_data *entry = (struct skb_data *) newsk->cb;
 425
 426	__skb_queue_tail(list, newsk);
 427	entry->state = state;
 428}
 429
 430/*-------------------------------------------------------------------------*/
 431
 432/* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 433 * completion callbacks.  2.5 should have fixed those bugs...
 434 */
 435
 436static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
 437		struct sk_buff_head *list, enum skb_state state)
 438{
 439	unsigned long		flags;
 440	enum skb_state 		old_state;
 441	struct skb_data *entry = (struct skb_data *) skb->cb;
 442
 443	spin_lock_irqsave(&list->lock, flags);
 444	old_state = entry->state;
 445	entry->state = state;
 446	__skb_unlink(skb, list);
 447
 448	/* defer_bh() is never called with list == &dev->done.
 449	 * spin_lock_nested() tells lockdep that it is OK to take
 450	 * dev->done.lock here with list->lock held.
 451	 */
 452	spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
 453
 454	__skb_queue_tail(&dev->done, skb);
 455	if (dev->done.qlen == 1)
 456		tasklet_schedule(&dev->bh);
 457	spin_unlock(&dev->done.lock);
 458	spin_unlock_irqrestore(&list->lock, flags);
 459	return old_state;
 460}
 461
 462/* some work can't be done in tasklets, so we use keventd
 463 *
 464 * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 465 * but tasklet_schedule() doesn't.  hope the failure is rare.
 466 */
 467void usbnet_defer_kevent (struct usbnet *dev, int work)
 468{
 469	set_bit (work, &dev->flags);
 470	if (!schedule_work (&dev->kevent))
 471		netdev_dbg(dev->net, "kevent %s may have been dropped\n", usbnet_event_names[work]);
 472	else
 473		netdev_dbg(dev->net, "kevent %s scheduled\n", usbnet_event_names[work]);
 474}
 475EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
 476
 477/*-------------------------------------------------------------------------*/
 478
 479static void rx_complete (struct urb *urb);
 480
 481static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
 482{
 483	struct sk_buff		*skb;
 484	struct skb_data		*entry;
 485	int			retval = 0;
 486	unsigned long		lockflags;
 487	size_t			size = dev->rx_urb_size;
 488
 489	/* prevent rx skb allocation when error ratio is high */
 490	if (test_bit(EVENT_RX_KILL, &dev->flags)) {
 491		usb_free_urb(urb);
 492		return -ENOLINK;
 493	}
 494
 495	if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
 496		skb = __netdev_alloc_skb(dev->net, size, flags);
 497	else
 498		skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
 499	if (!skb) {
 500		netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
 501		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 502		usb_free_urb (urb);
 503		return -ENOMEM;
 504	}
 505
 506	entry = (struct skb_data *) skb->cb;
 507	entry->urb = urb;
 508	entry->dev = dev;
 509	entry->length = 0;
 510
 511	usb_fill_bulk_urb (urb, dev->udev, dev->in,
 512		skb->data, size, rx_complete, skb);
 513
 514	spin_lock_irqsave (&dev->rxq.lock, lockflags);
 515
 516	if (netif_running (dev->net) &&
 517	    netif_device_present (dev->net) &&
 518	    test_bit(EVENT_DEV_OPEN, &dev->flags) &&
 519	    !test_bit (EVENT_RX_HALT, &dev->flags) &&
 520	    !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
 521		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
 522		case -EPIPE:
 523			usbnet_defer_kevent (dev, EVENT_RX_HALT);
 524			break;
 525		case -ENOMEM:
 526			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
 527			break;
 528		case -ENODEV:
 529			netif_dbg(dev, ifdown, dev->net, "device gone\n");
 530			netif_device_detach (dev->net);
 531			break;
 532		case -EHOSTUNREACH:
 533			retval = -ENOLINK;
 534			break;
 535		default:
 536			netif_dbg(dev, rx_err, dev->net,
 537				  "rx submit, %d\n", retval);
 538			tasklet_schedule (&dev->bh);
 539			break;
 540		case 0:
 541			__usbnet_queue_skb(&dev->rxq, skb, rx_start);
 542		}
 543	} else {
 544		netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
 545		retval = -ENOLINK;
 546	}
 547	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
 548	if (retval) {
 549		dev_kfree_skb_any (skb);
 550		usb_free_urb (urb);
 551	}
 552	return retval;
 553}
 554
 555
 556/*-------------------------------------------------------------------------*/
 557
 558static inline int rx_process(struct usbnet *dev, struct sk_buff *skb)
 559{
 560	if (dev->driver_info->rx_fixup &&
 561	    !dev->driver_info->rx_fixup (dev, skb)) {
 562		/* With RX_ASSEMBLE, rx_fixup() must update counters */
 563		if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
 564			dev->net->stats.rx_errors++;
 565		return -EPROTO;
 566	}
 567	// else network stack removes extra byte if we forced a short packet
 568
 569	/* all data was already cloned from skb inside the driver */
 570	if (dev->driver_info->flags & FLAG_MULTI_PACKET)
 571		return -EALREADY;
 572
 573	if (skb->len < ETH_HLEN) {
 574		dev->net->stats.rx_errors++;
 575		dev->net->stats.rx_length_errors++;
 576		netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
 577		return -EPROTO;
 
 
 578	}
 579
 580	usbnet_skb_return(dev, skb);
 581	return 0;
 582}
 583
 584/*-------------------------------------------------------------------------*/
 585
 586static void rx_complete (struct urb *urb)
 587{
 588	struct sk_buff		*skb = (struct sk_buff *) urb->context;
 589	struct skb_data		*entry = (struct skb_data *) skb->cb;
 590	struct usbnet		*dev = entry->dev;
 591	int			urb_status = urb->status;
 592	enum skb_state		state;
 593
 594	skb_put (skb, urb->actual_length);
 595	state = rx_done;
 596	entry->urb = NULL;
 597
 598	switch (urb_status) {
 599	/* success */
 600	case 0:
 601		break;
 602
 603	/* stalls need manual reset. this is rare ... except that
 604	 * when going through USB 2.0 TTs, unplug appears this way.
 605	 * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
 606	 * storm, recovering as needed.
 607	 */
 608	case -EPIPE:
 609		dev->net->stats.rx_errors++;
 610		usbnet_defer_kevent (dev, EVENT_RX_HALT);
 611		fallthrough;
 612
 613	/* software-driven interface shutdown */
 614	case -ECONNRESET:		/* async unlink */
 615	case -ESHUTDOWN:		/* hardware gone */
 616		netif_dbg(dev, ifdown, dev->net,
 617			  "rx shutdown, code %d\n", urb_status);
 618		goto block;
 619
 620	/* we get controller i/o faults during hub_wq disconnect() delays.
 621	 * throttle down resubmits, to avoid log floods; just temporarily,
 622	 * so we still recover when the fault isn't a hub_wq delay.
 623	 */
 624	case -EPROTO:
 625	case -ETIME:
 626	case -EILSEQ:
 627		dev->net->stats.rx_errors++;
 628		if (!timer_pending (&dev->delay)) {
 629			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
 630			netif_dbg(dev, link, dev->net,
 631				  "rx throttle %d\n", urb_status);
 632		}
 633block:
 634		state = rx_cleanup;
 635		entry->urb = urb;
 636		urb = NULL;
 637		break;
 638
 639	/* data overrun ... flush fifo? */
 640	case -EOVERFLOW:
 641		dev->net->stats.rx_over_errors++;
 642		fallthrough;
 643
 644	default:
 645		state = rx_cleanup;
 646		dev->net->stats.rx_errors++;
 647		netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
 648		break;
 649	}
 650
 651	/* stop rx if packet error rate is high */
 652	if (++dev->pkt_cnt > 30) {
 653		dev->pkt_cnt = 0;
 654		dev->pkt_err = 0;
 655	} else {
 656		if (state == rx_cleanup)
 657			dev->pkt_err++;
 658		if (dev->pkt_err > 20)
 659			set_bit(EVENT_RX_KILL, &dev->flags);
 660	}
 661
 662	state = defer_bh(dev, skb, &dev->rxq, state);
 663
 664	if (urb) {
 665		if (netif_running (dev->net) &&
 666		    !test_bit (EVENT_RX_HALT, &dev->flags) &&
 667		    state != unlink_start) {
 668			rx_submit (dev, urb, GFP_ATOMIC);
 669			usb_mark_last_busy(dev->udev);
 670			return;
 671		}
 672		usb_free_urb (urb);
 673	}
 674	netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
 675}
 676
 677/*-------------------------------------------------------------------------*/
 678void usbnet_pause_rx(struct usbnet *dev)
 679{
 680	set_bit(EVENT_RX_PAUSED, &dev->flags);
 681
 682	netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
 683}
 684EXPORT_SYMBOL_GPL(usbnet_pause_rx);
 685
 686void usbnet_resume_rx(struct usbnet *dev)
 687{
 688	struct sk_buff *skb;
 689	int num = 0;
 690
 691	clear_bit(EVENT_RX_PAUSED, &dev->flags);
 692
 693	while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
 694		usbnet_skb_return(dev, skb);
 695		num++;
 696	}
 697
 698	tasklet_schedule(&dev->bh);
 699
 700	netif_dbg(dev, rx_status, dev->net,
 701		  "paused rx queue disabled, %d skbs requeued\n", num);
 702}
 703EXPORT_SYMBOL_GPL(usbnet_resume_rx);
 704
 705void usbnet_purge_paused_rxq(struct usbnet *dev)
 706{
 707	skb_queue_purge(&dev->rxq_pause);
 708}
 709EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
 710
 711/*-------------------------------------------------------------------------*/
 712
 713// unlink pending rx/tx; completion handlers do all other cleanup
 714
 715static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
 716{
 717	unsigned long		flags;
 718	struct sk_buff		*skb;
 719	int			count = 0;
 720
 721	spin_lock_irqsave (&q->lock, flags);
 722	while (!skb_queue_empty(q)) {
 723		struct skb_data		*entry;
 724		struct urb		*urb;
 725		int			retval;
 726
 727		skb_queue_walk(q, skb) {
 728			entry = (struct skb_data *) skb->cb;
 729			if (entry->state != unlink_start)
 730				goto found;
 731		}
 732		break;
 733found:
 734		entry->state = unlink_start;
 735		urb = entry->urb;
 736
 737		/*
 738		 * Get reference count of the URB to avoid it to be
 739		 * freed during usb_unlink_urb, which may trigger
 740		 * use-after-free problem inside usb_unlink_urb since
 741		 * usb_unlink_urb is always racing with .complete
 742		 * handler(include defer_bh).
 743		 */
 744		usb_get_urb(urb);
 745		spin_unlock_irqrestore(&q->lock, flags);
 746		// during some PM-driven resume scenarios,
 747		// these (async) unlinks complete immediately
 748		retval = usb_unlink_urb (urb);
 749		if (retval != -EINPROGRESS && retval != 0)
 750			netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
 751		else
 752			count++;
 753		usb_put_urb(urb);
 754		spin_lock_irqsave(&q->lock, flags);
 755	}
 756	spin_unlock_irqrestore (&q->lock, flags);
 757	return count;
 758}
 759
 760// Flush all pending rx urbs
 761// minidrivers may need to do this when the MTU changes
 762
 763void usbnet_unlink_rx_urbs(struct usbnet *dev)
 764{
 765	if (netif_running(dev->net)) {
 766		(void) unlink_urbs (dev, &dev->rxq);
 767		tasklet_schedule(&dev->bh);
 768	}
 769}
 770EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
 771
 772/*-------------------------------------------------------------------------*/
 773
 774static void wait_skb_queue_empty(struct sk_buff_head *q)
 775{
 776	unsigned long flags;
 777
 778	spin_lock_irqsave(&q->lock, flags);
 779	while (!skb_queue_empty(q)) {
 780		spin_unlock_irqrestore(&q->lock, flags);
 781		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 782		set_current_state(TASK_UNINTERRUPTIBLE);
 783		spin_lock_irqsave(&q->lock, flags);
 784	}
 785	spin_unlock_irqrestore(&q->lock, flags);
 786}
 787
 788// precondition: never called in_interrupt
 789static void usbnet_terminate_urbs(struct usbnet *dev)
 790{
 791	DECLARE_WAITQUEUE(wait, current);
 792	int temp;
 793
 794	/* ensure there are no more active urbs */
 795	add_wait_queue(&dev->wait, &wait);
 796	set_current_state(TASK_UNINTERRUPTIBLE);
 797	temp = unlink_urbs(dev, &dev->txq) +
 798		unlink_urbs(dev, &dev->rxq);
 799
 800	/* maybe wait for deletions to finish. */
 801	wait_skb_queue_empty(&dev->rxq);
 802	wait_skb_queue_empty(&dev->txq);
 803	wait_skb_queue_empty(&dev->done);
 804	netif_dbg(dev, ifdown, dev->net,
 805		  "waited for %d urb completions\n", temp);
 806	set_current_state(TASK_RUNNING);
 807	remove_wait_queue(&dev->wait, &wait);
 808}
 809
 810int usbnet_stop (struct net_device *net)
 811{
 812	struct usbnet		*dev = netdev_priv(net);
 813	const struct driver_info *info = dev->driver_info;
 814	int			retval, pm, mpn;
 815
 816	clear_bit(EVENT_DEV_OPEN, &dev->flags);
 817	netif_stop_queue (net);
 818
 819	netif_info(dev, ifdown, dev->net,
 820		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 821		   net->stats.rx_packets, net->stats.tx_packets,
 822		   net->stats.rx_errors, net->stats.tx_errors);
 823
 824	/* to not race resume */
 825	pm = usb_autopm_get_interface(dev->intf);
 826	/* allow minidriver to stop correctly (wireless devices to turn off
 827	 * radio etc) */
 828	if (info->stop) {
 829		retval = info->stop(dev);
 830		if (retval < 0)
 831			netif_info(dev, ifdown, dev->net,
 832				   "stop fail (%d) usbnet usb-%s-%s, %s\n",
 833				   retval,
 834				   dev->udev->bus->bus_name, dev->udev->devpath,
 835				   info->description);
 836	}
 837
 838	if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
 839		usbnet_terminate_urbs(dev);
 840
 841	usbnet_status_stop(dev);
 842
 843	usbnet_purge_paused_rxq(dev);
 844
 845	mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
 846
 847	/* deferred work (timer, softirq, task) must also stop */
 
 
 
 848	dev->flags = 0;
 849	del_timer_sync (&dev->delay);
 850	tasklet_kill (&dev->bh);
 851	cancel_work_sync(&dev->kevent);
 852	if (!pm)
 853		usb_autopm_put_interface(dev->intf);
 854
 855	if (info->manage_power && mpn)
 856		info->manage_power(dev, 0);
 857	else
 858		usb_autopm_put_interface(dev->intf);
 859
 860	return 0;
 861}
 862EXPORT_SYMBOL_GPL(usbnet_stop);
 863
 864/*-------------------------------------------------------------------------*/
 865
 866// posts reads, and enables write queuing
 867
 868// precondition: never called in_interrupt
 869
 870int usbnet_open (struct net_device *net)
 871{
 872	struct usbnet		*dev = netdev_priv(net);
 873	int			retval;
 874	const struct driver_info *info = dev->driver_info;
 875
 876	if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
 877		netif_info(dev, ifup, dev->net,
 878			   "resumption fail (%d) usbnet usb-%s-%s, %s\n",
 879			   retval,
 880			   dev->udev->bus->bus_name,
 881			   dev->udev->devpath,
 882			   info->description);
 883		goto done_nopm;
 884	}
 885
 886	// put into "known safe" state
 887	if (info->reset && (retval = info->reset (dev)) < 0) {
 888		netif_info(dev, ifup, dev->net,
 889			   "open reset fail (%d) usbnet usb-%s-%s, %s\n",
 890			   retval,
 891			   dev->udev->bus->bus_name,
 892			   dev->udev->devpath,
 893			   info->description);
 894		goto done;
 895	}
 896
 897	/* hard_mtu or rx_urb_size may change in reset() */
 898	usbnet_update_max_qlen(dev);
 899
 900	// insist peer be connected
 901	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
 902		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
 903		goto done;
 904	}
 905
 906	/* start any status interrupt transfer */
 907	if (dev->interrupt) {
 908		retval = usbnet_status_start(dev, GFP_KERNEL);
 909		if (retval < 0) {
 910			netif_err(dev, ifup, dev->net,
 911				  "intr submit %d\n", retval);
 912			goto done;
 913		}
 914	}
 915
 916	set_bit(EVENT_DEV_OPEN, &dev->flags);
 917	netif_start_queue (net);
 918	netif_info(dev, ifup, dev->net,
 919		   "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
 920		   (int)RX_QLEN(dev), (int)TX_QLEN(dev),
 921		   dev->net->mtu,
 922		   (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
 923		   (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
 924		   (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
 925		   (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
 926		   (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
 927		   "simple");
 928
 929	/* reset rx error state */
 930	dev->pkt_cnt = 0;
 931	dev->pkt_err = 0;
 932	clear_bit(EVENT_RX_KILL, &dev->flags);
 933
 934	// delay posting reads until we're fully open
 935	tasklet_schedule (&dev->bh);
 936	if (info->manage_power) {
 937		retval = info->manage_power(dev, 1);
 938		if (retval < 0) {
 939			retval = 0;
 940			set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
 941		} else {
 942			usb_autopm_put_interface(dev->intf);
 943		}
 944	}
 945	return retval;
 946done:
 947	usb_autopm_put_interface(dev->intf);
 948done_nopm:
 949	return retval;
 950}
 951EXPORT_SYMBOL_GPL(usbnet_open);
 952
 953/*-------------------------------------------------------------------------*/
 954
 955/* ethtool methods; minidrivers may need to add some more, but
 956 * they'll probably want to use this base set.
 957 */
 958
 959/* These methods are written on the assumption that the device
 960 * uses MII
 961 */
 962int usbnet_get_link_ksettings_mii(struct net_device *net,
 963			      struct ethtool_link_ksettings *cmd)
 964{
 965	struct usbnet *dev = netdev_priv(net);
 966
 967	if (!dev->mii.mdio_read)
 968		return -EOPNOTSUPP;
 969
 970	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
 971
 972	return 0;
 973}
 974EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
 975
 976int usbnet_get_link_ksettings_internal(struct net_device *net,
 977					struct ethtool_link_ksettings *cmd)
 978{
 979	struct usbnet *dev = netdev_priv(net);
 980
 981	/* the assumption that speed is equal on tx and rx
 982	 * is deeply engrained into the networking layer.
 983	 * For wireless stuff it is not true.
 984	 * We assume that rx_speed matters more.
 985	 */
 986	if (dev->rx_speed != SPEED_UNSET)
 987		cmd->base.speed = dev->rx_speed / 1000000;
 988	else if (dev->tx_speed != SPEED_UNSET)
 989		cmd->base.speed = dev->tx_speed / 1000000;
 990	else
 991		cmd->base.speed = SPEED_UNKNOWN;
 992
 993	return 0;
 994}
 995EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
 996
 997int usbnet_set_link_ksettings_mii(struct net_device *net,
 998			      const struct ethtool_link_ksettings *cmd)
 999{
1000	struct usbnet *dev = netdev_priv(net);
1001	int retval;
1002
1003	if (!dev->mii.mdio_write)
1004		return -EOPNOTSUPP;
1005
1006	retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1007
1008	/* link speed/duplex might have changed */
1009	if (dev->driver_info->link_reset)
1010		dev->driver_info->link_reset(dev);
1011
1012	/* hard_mtu or rx_urb_size may change in link_reset() */
1013	usbnet_update_max_qlen(dev);
1014
1015	return retval;
1016}
1017EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1018
1019u32 usbnet_get_link (struct net_device *net)
1020{
1021	struct usbnet *dev = netdev_priv(net);
1022
1023	/* If a check_connect is defined, return its result */
1024	if (dev->driver_info->check_connect)
1025		return dev->driver_info->check_connect (dev) == 0;
1026
1027	/* if the device has mii operations, use those */
1028	if (dev->mii.mdio_read)
1029		return mii_link_ok(&dev->mii);
1030
1031	/* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1032	return ethtool_op_get_link(net);
1033}
1034EXPORT_SYMBOL_GPL(usbnet_get_link);
1035
1036int usbnet_nway_reset(struct net_device *net)
1037{
1038	struct usbnet *dev = netdev_priv(net);
1039
1040	if (!dev->mii.mdio_write)
1041		return -EOPNOTSUPP;
1042
1043	return mii_nway_restart(&dev->mii);
1044}
1045EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1046
1047void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1048{
1049	struct usbnet *dev = netdev_priv(net);
1050
1051	strscpy(info->driver, dev->driver_name, sizeof(info->driver));
1052	strscpy(info->fw_version, dev->driver_info->description,
1053		sizeof(info->fw_version));
1054	usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1055}
1056EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1057
1058u32 usbnet_get_msglevel (struct net_device *net)
1059{
1060	struct usbnet *dev = netdev_priv(net);
1061
1062	return dev->msg_enable;
1063}
1064EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1065
1066void usbnet_set_msglevel (struct net_device *net, u32 level)
1067{
1068	struct usbnet *dev = netdev_priv(net);
1069
1070	dev->msg_enable = level;
1071}
1072EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1073
1074/* drivers may override default ethtool_ops in their bind() routine */
1075static const struct ethtool_ops usbnet_ethtool_ops = {
1076	.get_link		= usbnet_get_link,
1077	.nway_reset		= usbnet_nway_reset,
1078	.get_drvinfo		= usbnet_get_drvinfo,
1079	.get_msglevel		= usbnet_get_msglevel,
1080	.set_msglevel		= usbnet_set_msglevel,
1081	.get_ts_info		= ethtool_op_get_ts_info,
1082	.get_link_ksettings	= usbnet_get_link_ksettings_mii,
1083	.set_link_ksettings	= usbnet_set_link_ksettings_mii,
1084};
1085
1086/*-------------------------------------------------------------------------*/
1087
1088static void __handle_link_change(struct usbnet *dev)
1089{
1090	if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1091		return;
1092
1093	if (!netif_carrier_ok(dev->net)) {
1094		/* kill URBs for reading packets to save bus bandwidth */
1095		unlink_urbs(dev, &dev->rxq);
1096
1097		/*
1098		 * tx_timeout will unlink URBs for sending packets and
1099		 * tx queue is stopped by netcore after link becomes off
1100		 */
1101	} else {
1102		/* submitting URBs for reading packets */
1103		tasklet_schedule(&dev->bh);
1104	}
1105
1106	/* hard_mtu or rx_urb_size may change during link change */
1107	usbnet_update_max_qlen(dev);
1108
1109	clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1110}
1111
1112void usbnet_set_rx_mode(struct net_device *net)
1113{
1114	struct usbnet		*dev = netdev_priv(net);
1115
1116	usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1117}
1118EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1119
1120static void __handle_set_rx_mode(struct usbnet *dev)
1121{
1122	if (dev->driver_info->set_rx_mode)
1123		(dev->driver_info->set_rx_mode)(dev);
1124
1125	clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1126}
1127
1128/* work that cannot be done in interrupt context uses keventd.
1129 *
1130 * NOTE:  with 2.5 we could do more of this using completion callbacks,
1131 * especially now that control transfers can be queued.
1132 */
1133static void
1134usbnet_deferred_kevent (struct work_struct *work)
1135{
1136	struct usbnet		*dev =
1137		container_of(work, struct usbnet, kevent);
1138	int			status;
1139
1140	/* usb_clear_halt() needs a thread context */
1141	if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1142		unlink_urbs (dev, &dev->txq);
1143		status = usb_autopm_get_interface(dev->intf);
1144		if (status < 0)
1145			goto fail_pipe;
1146		status = usb_clear_halt (dev->udev, dev->out);
1147		usb_autopm_put_interface(dev->intf);
1148		if (status < 0 &&
1149		    status != -EPIPE &&
1150		    status != -ESHUTDOWN) {
1151			if (netif_msg_tx_err (dev))
1152fail_pipe:
1153				netdev_err(dev->net, "can't clear tx halt, status %d\n",
1154					   status);
1155		} else {
1156			clear_bit (EVENT_TX_HALT, &dev->flags);
1157			if (status != -ESHUTDOWN)
1158				netif_wake_queue (dev->net);
1159		}
1160	}
1161	if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1162		unlink_urbs (dev, &dev->rxq);
1163		status = usb_autopm_get_interface(dev->intf);
1164		if (status < 0)
1165			goto fail_halt;
1166		status = usb_clear_halt (dev->udev, dev->in);
1167		usb_autopm_put_interface(dev->intf);
1168		if (status < 0 &&
1169		    status != -EPIPE &&
1170		    status != -ESHUTDOWN) {
1171			if (netif_msg_rx_err (dev))
1172fail_halt:
1173				netdev_err(dev->net, "can't clear rx halt, status %d\n",
1174					   status);
1175		} else {
1176			clear_bit (EVENT_RX_HALT, &dev->flags);
1177			tasklet_schedule (&dev->bh);
1178		}
1179	}
1180
1181	/* tasklet could resubmit itself forever if memory is tight */
1182	if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1183		struct urb	*urb = NULL;
1184		int resched = 1;
1185
1186		if (netif_running (dev->net))
1187			urb = usb_alloc_urb (0, GFP_KERNEL);
1188		else
1189			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1190		if (urb != NULL) {
1191			clear_bit (EVENT_RX_MEMORY, &dev->flags);
1192			status = usb_autopm_get_interface(dev->intf);
1193			if (status < 0) {
1194				usb_free_urb(urb);
1195				goto fail_lowmem;
1196			}
1197			if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1198				resched = 0;
1199			usb_autopm_put_interface(dev->intf);
1200fail_lowmem:
1201			if (resched)
1202				tasklet_schedule (&dev->bh);
1203		}
1204	}
1205
1206	if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1207		const struct driver_info *info = dev->driver_info;
1208		int			retval = 0;
1209
1210		clear_bit (EVENT_LINK_RESET, &dev->flags);
1211		status = usb_autopm_get_interface(dev->intf);
1212		if (status < 0)
1213			goto skip_reset;
1214		if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1215			usb_autopm_put_interface(dev->intf);
1216skip_reset:
1217			netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1218				    retval,
1219				    dev->udev->bus->bus_name,
1220				    dev->udev->devpath,
1221				    info->description);
1222		} else {
1223			usb_autopm_put_interface(dev->intf);
1224		}
1225
1226		/* handle link change from link resetting */
1227		__handle_link_change(dev);
1228	}
1229
1230	if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1231		__handle_link_change(dev);
1232
1233	if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1234		__handle_set_rx_mode(dev);
1235
1236
1237	if (dev->flags)
1238		netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1239}
1240
1241/*-------------------------------------------------------------------------*/
1242
1243static void tx_complete (struct urb *urb)
1244{
1245	struct sk_buff		*skb = (struct sk_buff *) urb->context;
1246	struct skb_data		*entry = (struct skb_data *) skb->cb;
1247	struct usbnet		*dev = entry->dev;
1248
1249	if (urb->status == 0) {
1250		struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1251		unsigned long flags;
1252
1253		flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1254		u64_stats_add(&stats64->tx_packets, entry->packets);
1255		u64_stats_add(&stats64->tx_bytes, entry->length);
1256		u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1257	} else {
1258		dev->net->stats.tx_errors++;
1259
1260		switch (urb->status) {
1261		case -EPIPE:
1262			usbnet_defer_kevent (dev, EVENT_TX_HALT);
1263			break;
1264
1265		/* software-driven interface shutdown */
1266		case -ECONNRESET:		// async unlink
1267		case -ESHUTDOWN:		// hardware gone
1268			break;
1269
1270		/* like rx, tx gets controller i/o faults during hub_wq
1271		 * delays and so it uses the same throttling mechanism.
1272		 */
1273		case -EPROTO:
1274		case -ETIME:
1275		case -EILSEQ:
1276			usb_mark_last_busy(dev->udev);
1277			if (!timer_pending (&dev->delay)) {
1278				mod_timer (&dev->delay,
1279					jiffies + THROTTLE_JIFFIES);
1280				netif_dbg(dev, link, dev->net,
1281					  "tx throttle %d\n", urb->status);
1282			}
1283			netif_stop_queue (dev->net);
1284			break;
1285		default:
1286			netif_dbg(dev, tx_err, dev->net,
1287				  "tx err %d\n", entry->urb->status);
1288			break;
1289		}
1290	}
1291
1292	usb_autopm_put_interface_async(dev->intf);
1293	(void) defer_bh(dev, skb, &dev->txq, tx_done);
1294}
1295
1296/*-------------------------------------------------------------------------*/
1297
1298void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1299{
1300	struct usbnet		*dev = netdev_priv(net);
1301
1302	unlink_urbs (dev, &dev->txq);
1303	tasklet_schedule (&dev->bh);
1304	/* this needs to be handled individually because the generic layer
1305	 * doesn't know what is sufficient and could not restore private
1306	 * information if a remedy of an unconditional reset were used.
1307	 */
1308	if (dev->driver_info->recover)
1309		(dev->driver_info->recover)(dev);
1310}
1311EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1312
1313/*-------------------------------------------------------------------------*/
1314
1315static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1316{
1317	unsigned num_sgs, total_len = 0;
1318	int i, s = 0;
1319
1320	num_sgs = skb_shinfo(skb)->nr_frags + 1;
1321	if (num_sgs == 1)
1322		return 0;
1323
1324	/* reserve one for zero packet */
1325	urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1326				GFP_ATOMIC);
1327	if (!urb->sg)
1328		return -ENOMEM;
1329
1330	urb->num_sgs = num_sgs;
1331	sg_init_table(urb->sg, urb->num_sgs + 1);
1332
1333	sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1334	total_len += skb_headlen(skb);
1335
1336	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1337		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1338
1339		total_len += skb_frag_size(f);
1340		sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1341			    skb_frag_off(f));
1342	}
1343	urb->transfer_buffer_length = total_len;
1344
1345	return 1;
1346}
1347
1348netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1349				     struct net_device *net)
1350{
1351	struct usbnet		*dev = netdev_priv(net);
1352	unsigned int			length;
1353	struct urb		*urb = NULL;
1354	struct skb_data		*entry;
1355	const struct driver_info *info = dev->driver_info;
1356	unsigned long		flags;
1357	int retval;
1358
1359	if (skb)
1360		skb_tx_timestamp(skb);
1361
1362	// some devices want funky USB-level framing, for
1363	// win32 driver (usually) and/or hardware quirks
1364	if (info->tx_fixup) {
1365		skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1366		if (!skb) {
1367			/* packet collected; minidriver waiting for more */
1368			if (info->flags & FLAG_MULTI_PACKET)
1369				goto not_drop;
1370			netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1371			goto drop;
1372		}
1373	}
1374
1375	if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1376		netif_dbg(dev, tx_err, dev->net, "no urb\n");
1377		goto drop;
1378	}
1379
1380	entry = (struct skb_data *) skb->cb;
1381	entry->urb = urb;
1382	entry->dev = dev;
1383
1384	usb_fill_bulk_urb (urb, dev->udev, dev->out,
1385			skb->data, skb->len, tx_complete, skb);
1386	if (dev->can_dma_sg) {
1387		if (build_dma_sg(skb, urb) < 0)
1388			goto drop;
1389	}
1390	length = urb->transfer_buffer_length;
1391
1392	/* don't assume the hardware handles USB_ZERO_PACKET
1393	 * NOTE:  strictly conforming cdc-ether devices should expect
1394	 * the ZLP here, but ignore the one-byte packet.
1395	 * NOTE2: CDC NCM specification is different from CDC ECM when
1396	 * handling ZLP/short packets, so cdc_ncm driver will make short
1397	 * packet itself if needed.
1398	 */
1399	if (length % dev->maxpacket == 0) {
1400		if (!(info->flags & FLAG_SEND_ZLP)) {
1401			if (!(info->flags & FLAG_MULTI_PACKET)) {
1402				length++;
1403				if (skb_tailroom(skb) && !urb->num_sgs) {
1404					skb->data[skb->len] = 0;
1405					__skb_put(skb, 1);
1406				} else if (urb->num_sgs)
1407					sg_set_buf(&urb->sg[urb->num_sgs++],
1408							dev->padding_pkt, 1);
1409			}
1410		} else
1411			urb->transfer_flags |= URB_ZERO_PACKET;
1412	}
1413	urb->transfer_buffer_length = length;
1414
1415	if (info->flags & FLAG_MULTI_PACKET) {
1416		/* Driver has set number of packets and a length delta.
1417		 * Calculate the complete length and ensure that it's
1418		 * positive.
1419		 */
1420		entry->length += length;
1421		if (WARN_ON_ONCE(entry->length <= 0))
1422			entry->length = length;
1423	} else {
1424		usbnet_set_skb_tx_stats(skb, 1, length);
1425	}
1426
1427	spin_lock_irqsave(&dev->txq.lock, flags);
1428	retval = usb_autopm_get_interface_async(dev->intf);
1429	if (retval < 0) {
1430		spin_unlock_irqrestore(&dev->txq.lock, flags);
1431		goto drop;
1432	}
1433	if (netif_queue_stopped(net)) {
1434		usb_autopm_put_interface_async(dev->intf);
1435		spin_unlock_irqrestore(&dev->txq.lock, flags);
1436		goto drop;
1437	}
1438
1439#ifdef CONFIG_PM
1440	/* if this triggers the device is still a sleep */
1441	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1442		/* transmission will be done in resume */
1443		usb_anchor_urb(urb, &dev->deferred);
1444		/* no use to process more packets */
1445		netif_stop_queue(net);
1446		usb_put_urb(urb);
1447		spin_unlock_irqrestore(&dev->txq.lock, flags);
1448		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1449		goto deferred;
1450	}
1451#endif
1452
1453	switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1454	case -EPIPE:
1455		netif_stop_queue (net);
1456		usbnet_defer_kevent (dev, EVENT_TX_HALT);
1457		usb_autopm_put_interface_async(dev->intf);
1458		break;
1459	default:
1460		usb_autopm_put_interface_async(dev->intf);
1461		netif_dbg(dev, tx_err, dev->net,
1462			  "tx: submit urb err %d\n", retval);
1463		break;
1464	case 0:
1465		netif_trans_update(net);
1466		__usbnet_queue_skb(&dev->txq, skb, tx_start);
1467		if (dev->txq.qlen >= TX_QLEN (dev))
1468			netif_stop_queue (net);
1469	}
1470	spin_unlock_irqrestore (&dev->txq.lock, flags);
1471
1472	if (retval) {
1473		netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1474drop:
1475		dev->net->stats.tx_dropped++;
1476not_drop:
1477		if (skb)
1478			dev_kfree_skb_any (skb);
1479		if (urb) {
1480			kfree(urb->sg);
1481			usb_free_urb(urb);
1482		}
1483	} else
1484		netif_dbg(dev, tx_queued, dev->net,
1485			  "> tx, len %u, type 0x%x\n", length, skb->protocol);
1486#ifdef CONFIG_PM
1487deferred:
1488#endif
1489	return NETDEV_TX_OK;
1490}
1491EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1492
1493static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1494{
1495	struct urb	*urb;
1496	int		i;
1497	int		ret = 0;
1498
1499	/* don't refill the queue all at once */
1500	for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1501		urb = usb_alloc_urb(0, flags);
1502		if (urb != NULL) {
1503			ret = rx_submit(dev, urb, flags);
1504			if (ret)
1505				goto err;
1506		} else {
1507			ret = -ENOMEM;
1508			goto err;
1509		}
1510	}
1511err:
1512	return ret;
1513}
1514
1515static inline void usb_free_skb(struct sk_buff *skb)
1516{
1517	struct skb_data *entry = (struct skb_data *)skb->cb;
1518
1519	usb_free_urb(entry->urb);
1520	dev_kfree_skb(skb);
1521}
1522
1523/*-------------------------------------------------------------------------*/
1524
1525// tasklet (work deferred from completions, in_irq) or timer
1526
1527static void usbnet_bh (struct timer_list *t)
1528{
1529	struct usbnet		*dev = from_timer(dev, t, delay);
1530	struct sk_buff		*skb;
1531	struct skb_data		*entry;
1532
1533	while ((skb = skb_dequeue (&dev->done))) {
1534		entry = (struct skb_data *) skb->cb;
1535		switch (entry->state) {
1536		case rx_done:
1537			if (rx_process(dev, skb))
1538				usb_free_skb(skb);
1539			continue;
1540		case tx_done:
1541			kfree(entry->urb->sg);
1542			fallthrough;
1543		case rx_cleanup:
1544			usb_free_skb(skb);
 
1545			continue;
1546		default:
1547			netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1548		}
1549	}
1550
1551	/* restart RX again after disabling due to high error rate */
1552	clear_bit(EVENT_RX_KILL, &dev->flags);
1553
1554	/* waiting for all pending urbs to complete?
1555	 * only then can we forgo submitting anew
1556	 */
1557	if (waitqueue_active(&dev->wait)) {
1558		if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1559			wake_up_all(&dev->wait);
1560
1561	// or are we maybe short a few urbs?
1562	} else if (netif_running (dev->net) &&
1563		   netif_device_present (dev->net) &&
1564		   netif_carrier_ok(dev->net) &&
1565		   !timer_pending(&dev->delay) &&
1566		   !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1567		   !test_bit(EVENT_RX_HALT, &dev->flags)) {
1568		int	temp = dev->rxq.qlen;
1569
1570		if (temp < RX_QLEN(dev)) {
1571			if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1572				return;
1573			if (temp != dev->rxq.qlen)
1574				netif_dbg(dev, link, dev->net,
1575					  "rxqlen %d --> %d\n",
1576					  temp, dev->rxq.qlen);
1577			if (dev->rxq.qlen < RX_QLEN(dev))
1578				tasklet_schedule (&dev->bh);
1579		}
1580		if (dev->txq.qlen < TX_QLEN (dev))
1581			netif_wake_queue (dev->net);
1582	}
1583}
1584
1585static void usbnet_bh_tasklet(struct tasklet_struct *t)
1586{
1587	struct usbnet *dev = from_tasklet(dev, t, bh);
1588
1589	usbnet_bh(&dev->delay);
1590}
1591
1592
1593/*-------------------------------------------------------------------------
1594 *
1595 * USB Device Driver support
1596 *
1597 *-------------------------------------------------------------------------*/
1598
1599// precondition: never called in_interrupt
1600
1601void usbnet_disconnect (struct usb_interface *intf)
1602{
1603	struct usbnet		*dev;
1604	struct usb_device	*xdev;
1605	struct net_device	*net;
1606	struct urb		*urb;
1607
1608	dev = usb_get_intfdata(intf);
1609	usb_set_intfdata(intf, NULL);
1610	if (!dev)
1611		return;
1612
1613	xdev = interface_to_usbdev (intf);
1614
1615	netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1616		   intf->dev.driver->name,
1617		   xdev->bus->bus_name, xdev->devpath,
1618		   dev->driver_info->description);
1619
 
 
 
1620	net = dev->net;
1621	unregister_netdev (net);
1622
1623	while ((urb = usb_get_from_anchor(&dev->deferred))) {
1624		dev_kfree_skb(urb->context);
1625		kfree(urb->sg);
1626		usb_free_urb(urb);
1627	}
1628
1629	if (dev->driver_info->unbind)
1630		dev->driver_info->unbind(dev, intf);
1631
1632	usb_kill_urb(dev->interrupt);
1633	usb_free_urb(dev->interrupt);
1634	kfree(dev->padding_pkt);
1635
1636	free_percpu(net->tstats);
1637	free_netdev(net);
1638}
1639EXPORT_SYMBOL_GPL(usbnet_disconnect);
1640
1641static const struct net_device_ops usbnet_netdev_ops = {
1642	.ndo_open		= usbnet_open,
1643	.ndo_stop		= usbnet_stop,
1644	.ndo_start_xmit		= usbnet_start_xmit,
1645	.ndo_tx_timeout		= usbnet_tx_timeout,
1646	.ndo_set_rx_mode	= usbnet_set_rx_mode,
1647	.ndo_change_mtu		= usbnet_change_mtu,
1648	.ndo_get_stats64	= dev_get_tstats64,
1649	.ndo_set_mac_address 	= eth_mac_addr,
1650	.ndo_validate_addr	= eth_validate_addr,
1651};
1652
1653/*-------------------------------------------------------------------------*/
1654
1655// precondition: never called in_interrupt
1656
1657static struct device_type wlan_type = {
1658	.name	= "wlan",
1659};
1660
1661static struct device_type wwan_type = {
1662	.name	= "wwan",
1663};
1664
1665int
1666usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1667{
1668	struct usbnet			*dev;
1669	struct net_device		*net;
1670	struct usb_host_interface	*interface;
1671	const struct driver_info	*info;
1672	struct usb_device		*xdev;
1673	int				status;
1674	const char			*name;
1675	struct usb_driver 	*driver = to_usb_driver(udev->dev.driver);
1676
1677	/* usbnet already took usb runtime pm, so have to enable the feature
1678	 * for usb interface, otherwise usb_autopm_get_interface may return
1679	 * failure if RUNTIME_PM is enabled.
1680	 */
1681	if (!driver->supports_autosuspend) {
1682		driver->supports_autosuspend = 1;
1683		pm_runtime_enable(&udev->dev);
1684	}
1685
1686	name = udev->dev.driver->name;
1687	info = (const struct driver_info *) prod->driver_info;
1688	if (!info) {
1689		dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1690		return -ENODEV;
1691	}
1692	xdev = interface_to_usbdev (udev);
1693	interface = udev->cur_altsetting;
1694
1695	status = -ENOMEM;
1696
1697	// set up our own records
1698	net = alloc_etherdev(sizeof(*dev));
1699	if (!net)
1700		goto out;
1701
1702	/* netdev_printk() needs this so do it as early as possible */
1703	SET_NETDEV_DEV(net, &udev->dev);
1704
1705	dev = netdev_priv(net);
1706	dev->udev = xdev;
1707	dev->intf = udev;
1708	dev->driver_info = info;
1709	dev->driver_name = name;
1710	dev->rx_speed = SPEED_UNSET;
1711	dev->tx_speed = SPEED_UNSET;
1712
1713	net->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1714	if (!net->tstats)
1715		goto out0;
1716
1717	dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1718				| NETIF_MSG_PROBE | NETIF_MSG_LINK);
1719	init_waitqueue_head(&dev->wait);
1720	skb_queue_head_init (&dev->rxq);
1721	skb_queue_head_init (&dev->txq);
1722	skb_queue_head_init (&dev->done);
1723	skb_queue_head_init(&dev->rxq_pause);
1724	tasklet_setup(&dev->bh, usbnet_bh_tasklet);
1725	INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1726	init_usb_anchor(&dev->deferred);
1727	timer_setup(&dev->delay, usbnet_bh, 0);
1728	mutex_init (&dev->phy_mutex);
1729	mutex_init(&dev->interrupt_mutex);
1730	dev->interrupt_count = 0;
1731
1732	dev->net = net;
1733	strscpy(net->name, "usb%d", sizeof(net->name));
1734	eth_hw_addr_set(net, node_id);
1735
1736	/* rx and tx sides can use different message sizes;
1737	 * bind() should set rx_urb_size in that case.
1738	 */
1739	dev->hard_mtu = net->mtu + net->hard_header_len;
1740	net->min_mtu = 0;
1741	net->max_mtu = ETH_MAX_MTU;
1742
1743	net->netdev_ops = &usbnet_netdev_ops;
1744	net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1745	net->ethtool_ops = &usbnet_ethtool_ops;
1746
1747	// allow device-specific bind/init procedures
1748	// NOTE net->name still not usable ...
1749	if (info->bind) {
1750		status = info->bind (dev, udev);
1751		if (status < 0)
1752			goto out1;
1753
1754		// heuristic:  "usb%d" for links we know are two-host,
1755		// else "eth%d" when there's reasonable doubt.  userspace
1756		// can rename the link if it knows better.
1757		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1758		    ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1759		     (net->dev_addr [0] & 0x02) == 0))
1760			strscpy(net->name, "eth%d", sizeof(net->name));
1761		/* WLAN devices should always be named "wlan%d" */
1762		if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1763			strscpy(net->name, "wlan%d", sizeof(net->name));
1764		/* WWAN devices should always be named "wwan%d" */
1765		if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1766			strscpy(net->name, "wwan%d", sizeof(net->name));
1767
1768		/* devices that cannot do ARP */
1769		if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1770			net->flags |= IFF_NOARP;
1771
1772		/* maybe the remote can't receive an Ethernet MTU */
1773		if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1774			net->mtu = dev->hard_mtu - net->hard_header_len;
1775	} else if (!info->in || !info->out)
1776		status = usbnet_get_endpoints (dev, udev);
1777	else {
1778		u8 ep_addrs[3] = {
1779			info->in + USB_DIR_IN, info->out + USB_DIR_OUT, 0
1780		};
1781
1782		dev->in = usb_rcvbulkpipe (xdev, info->in);
1783		dev->out = usb_sndbulkpipe (xdev, info->out);
1784		if (!(info->flags & FLAG_NO_SETINT))
1785			status = usb_set_interface (xdev,
1786				interface->desc.bInterfaceNumber,
1787				interface->desc.bAlternateSetting);
1788		else
1789			status = 0;
1790
1791		if (status == 0 && !usb_check_bulk_endpoints(udev, ep_addrs))
1792			status = -EINVAL;
1793	}
1794	if (status >= 0 && dev->status)
1795		status = init_status (dev, udev);
1796	if (status < 0)
1797		goto out3;
1798
1799	if (!dev->rx_urb_size)
1800		dev->rx_urb_size = dev->hard_mtu;
1801	dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
1802	if (dev->maxpacket == 0) {
1803		/* that is a broken device */
1804		status = -ENODEV;
1805		goto out4;
1806	}
1807
1808	/* let userspace know we have a random address */
1809	if (ether_addr_equal(net->dev_addr, node_id))
1810		net->addr_assign_type = NET_ADDR_RANDOM;
1811
1812	if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1813		SET_NETDEV_DEVTYPE(net, &wlan_type);
1814	if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1815		SET_NETDEV_DEVTYPE(net, &wwan_type);
1816
1817	/* initialize max rx_qlen and tx_qlen */
1818	usbnet_update_max_qlen(dev);
1819
1820	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1821		!(info->flags & FLAG_MULTI_PACKET)) {
1822		dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1823		if (!dev->padding_pkt) {
1824			status = -ENOMEM;
1825			goto out4;
1826		}
1827	}
1828
1829	status = register_netdev (net);
1830	if (status)
1831		goto out5;
1832	netif_info(dev, probe, dev->net,
1833		   "register '%s' at usb-%s-%s, %s, %pM\n",
1834		   udev->dev.driver->name,
1835		   xdev->bus->bus_name, xdev->devpath,
1836		   dev->driver_info->description,
1837		   net->dev_addr);
1838
1839	// ok, it's ready to go.
1840	usb_set_intfdata (udev, dev);
1841
1842	netif_device_attach (net);
1843
1844	if (dev->driver_info->flags & FLAG_LINK_INTR)
1845		usbnet_link_change(dev, 0, 0);
1846
1847	return 0;
1848
1849out5:
1850	kfree(dev->padding_pkt);
1851out4:
1852	usb_free_urb(dev->interrupt);
1853out3:
1854	if (info->unbind)
1855		info->unbind (dev, udev);
1856out1:
1857	/* subdrivers must undo all they did in bind() if they
1858	 * fail it, but we may fail later and a deferred kevent
1859	 * may trigger an error resubmitting itself and, worse,
1860	 * schedule a timer. So we kill it all just in case.
1861	 */
1862	cancel_work_sync(&dev->kevent);
1863	del_timer_sync(&dev->delay);
1864	free_percpu(net->tstats);
1865out0:
1866	free_netdev(net);
1867out:
1868	return status;
1869}
1870EXPORT_SYMBOL_GPL(usbnet_probe);
1871
1872/*-------------------------------------------------------------------------*/
1873
1874/*
1875 * suspend the whole driver as soon as the first interface is suspended
1876 * resume only when the last interface is resumed
1877 */
1878
1879int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1880{
1881	struct usbnet		*dev = usb_get_intfdata(intf);
1882
1883	if (!dev->suspend_count++) {
1884		spin_lock_irq(&dev->txq.lock);
1885		/* don't autosuspend while transmitting */
1886		if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1887			dev->suspend_count--;
1888			spin_unlock_irq(&dev->txq.lock);
1889			return -EBUSY;
1890		} else {
1891			set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1892			spin_unlock_irq(&dev->txq.lock);
1893		}
1894		/*
1895		 * accelerate emptying of the rx and queues, to avoid
1896		 * having everything error out.
1897		 */
1898		netif_device_detach (dev->net);
1899		usbnet_terminate_urbs(dev);
1900		__usbnet_status_stop_force(dev);
1901
1902		/*
1903		 * reattach so runtime management can use and
1904		 * wake the device
1905		 */
1906		netif_device_attach (dev->net);
1907	}
1908	return 0;
1909}
1910EXPORT_SYMBOL_GPL(usbnet_suspend);
1911
1912int usbnet_resume (struct usb_interface *intf)
1913{
1914	struct usbnet		*dev = usb_get_intfdata(intf);
1915	struct sk_buff          *skb;
1916	struct urb              *res;
1917	int                     retval;
1918
1919	if (!--dev->suspend_count) {
1920		/* resume interrupt URB if it was previously submitted */
1921		__usbnet_status_start_force(dev, GFP_NOIO);
1922
1923		spin_lock_irq(&dev->txq.lock);
1924		while ((res = usb_get_from_anchor(&dev->deferred))) {
1925
1926			skb = (struct sk_buff *)res->context;
1927			retval = usb_submit_urb(res, GFP_ATOMIC);
1928			if (retval < 0) {
1929				dev_kfree_skb_any(skb);
1930				kfree(res->sg);
1931				usb_free_urb(res);
1932				usb_autopm_put_interface_async(dev->intf);
1933			} else {
1934				netif_trans_update(dev->net);
1935				__skb_queue_tail(&dev->txq, skb);
1936			}
1937		}
1938
1939		smp_mb();
1940		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1941		spin_unlock_irq(&dev->txq.lock);
1942
1943		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1944			/* handle remote wakeup ASAP
1945			 * we cannot race against stop
1946			 */
1947			if (netif_device_present(dev->net) &&
1948				!timer_pending(&dev->delay) &&
1949				!test_bit(EVENT_RX_HALT, &dev->flags))
1950					rx_alloc_submit(dev, GFP_NOIO);
1951
1952			if (!(dev->txq.qlen >= TX_QLEN(dev)))
1953				netif_tx_wake_all_queues(dev->net);
1954			tasklet_schedule (&dev->bh);
1955		}
1956	}
1957
1958	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1959		usb_autopm_get_interface_no_resume(intf);
1960
1961	return 0;
1962}
1963EXPORT_SYMBOL_GPL(usbnet_resume);
1964
1965/*
1966 * Either a subdriver implements manage_power, then it is assumed to always
1967 * be ready to be suspended or it reports the readiness to be suspended
1968 * explicitly
1969 */
1970void usbnet_device_suggests_idle(struct usbnet *dev)
1971{
1972	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1973		dev->intf->needs_remote_wakeup = 1;
1974		usb_autopm_put_interface_async(dev->intf);
1975	}
1976}
1977EXPORT_SYMBOL(usbnet_device_suggests_idle);
1978
1979/*
1980 * For devices that can do without special commands
1981 */
1982int usbnet_manage_power(struct usbnet *dev, int on)
1983{
1984	dev->intf->needs_remote_wakeup = on;
1985	return 0;
1986}
1987EXPORT_SYMBOL(usbnet_manage_power);
1988
1989void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1990{
1991	/* update link after link is reseted */
1992	if (link && !need_reset)
1993		netif_carrier_on(dev->net);
1994	else
1995		netif_carrier_off(dev->net);
1996
1997	if (need_reset && link)
1998		usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1999	else
2000		usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
2001}
2002EXPORT_SYMBOL(usbnet_link_change);
2003
2004/*-------------------------------------------------------------------------*/
2005static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2006			     u16 value, u16 index, void *data, u16 size)
2007{
2008	void *buf = NULL;
2009	int err = -ENOMEM;
2010
2011	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
2012		   " value=0x%04x index=0x%04x size=%d\n",
2013		   cmd, reqtype, value, index, size);
2014
2015	if (size) {
2016		buf = kmalloc(size, GFP_NOIO);
2017		if (!buf)
2018			goto out;
2019	}
2020
2021	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2022			      cmd, reqtype, value, index, buf, size,
2023			      USB_CTRL_GET_TIMEOUT);
2024	if (err > 0 && err <= size) {
2025		if (data)
2026			memcpy(data, buf, err);
2027		else
2028			netdev_dbg(dev->net,
2029				   "Huh? Data requested but thrown away.\n");
2030	}
2031	kfree(buf);
2032out:
2033	return err;
2034}
2035
2036static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2037			      u16 value, u16 index, const void *data,
2038			      u16 size)
2039{
2040	void *buf = NULL;
2041	int err = -ENOMEM;
2042
2043	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2044		   " value=0x%04x index=0x%04x size=%d\n",
2045		   cmd, reqtype, value, index, size);
2046
2047	if (data) {
2048		buf = kmemdup(data, size, GFP_NOIO);
2049		if (!buf)
2050			goto out;
2051	} else {
2052        if (size) {
2053            WARN_ON_ONCE(1);
2054            err = -EINVAL;
2055            goto out;
2056        }
2057    }
2058
2059	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2060			      cmd, reqtype, value, index, buf, size,
2061			      USB_CTRL_SET_TIMEOUT);
2062	kfree(buf);
2063
2064out:
2065	return err;
2066}
2067
2068/*
2069 * The function can't be called inside suspend/resume callback,
2070 * otherwise deadlock will be caused.
2071 */
2072int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2073		    u16 value, u16 index, void *data, u16 size)
2074{
2075	int ret;
2076
2077	if (usb_autopm_get_interface(dev->intf) < 0)
2078		return -ENODEV;
2079	ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2080				data, size);
2081	usb_autopm_put_interface(dev->intf);
2082	return ret;
2083}
2084EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2085
2086/*
2087 * The function can't be called inside suspend/resume callback,
2088 * otherwise deadlock will be caused.
2089 */
2090int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2091		     u16 value, u16 index, const void *data, u16 size)
2092{
2093	int ret;
2094
2095	if (usb_autopm_get_interface(dev->intf) < 0)
2096		return -ENODEV;
2097	ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2098				 data, size);
2099	usb_autopm_put_interface(dev->intf);
2100	return ret;
2101}
2102EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2103
2104/*
2105 * The function can be called inside suspend/resume callback safely
2106 * and should only be called by suspend/resume callback generally.
2107 */
2108int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2109			  u16 value, u16 index, void *data, u16 size)
2110{
2111	return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2112				 data, size);
2113}
2114EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2115
2116/*
2117 * The function can be called inside suspend/resume callback safely
2118 * and should only be called by suspend/resume callback generally.
2119 */
2120int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2121			  u16 value, u16 index, const void *data,
2122			  u16 size)
2123{
2124	return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2125				  data, size);
2126}
2127EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2128
2129static void usbnet_async_cmd_cb(struct urb *urb)
2130{
2131	struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2132	int status = urb->status;
2133
2134	if (status < 0)
2135		dev_dbg(&urb->dev->dev, "%s failed with %d",
2136			__func__, status);
2137
2138	kfree(req);
2139	usb_free_urb(urb);
2140}
2141
2142/*
2143 * The caller must make sure that device can't be put into suspend
2144 * state until the control URB completes.
2145 */
2146int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2147			   u16 value, u16 index, const void *data, u16 size)
2148{
2149	struct usb_ctrlrequest *req;
2150	struct urb *urb;
2151	int err = -ENOMEM;
2152	void *buf = NULL;
2153
2154	netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2155		   " value=0x%04x index=0x%04x size=%d\n",
2156		   cmd, reqtype, value, index, size);
2157
2158	urb = usb_alloc_urb(0, GFP_ATOMIC);
2159	if (!urb)
2160		goto fail;
2161
2162	if (data) {
2163		buf = kmemdup(data, size, GFP_ATOMIC);
2164		if (!buf) {
2165			netdev_err(dev->net, "Error allocating buffer"
2166				   " in %s!\n", __func__);
2167			goto fail_free_urb;
2168		}
2169	}
2170
2171	req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2172	if (!req)
2173		goto fail_free_buf;
2174
2175	req->bRequestType = reqtype;
2176	req->bRequest = cmd;
2177	req->wValue = cpu_to_le16(value);
2178	req->wIndex = cpu_to_le16(index);
2179	req->wLength = cpu_to_le16(size);
2180
2181	usb_fill_control_urb(urb, dev->udev,
2182			     usb_sndctrlpipe(dev->udev, 0),
2183			     (void *)req, buf, size,
2184			     usbnet_async_cmd_cb, req);
2185	urb->transfer_flags |= URB_FREE_BUFFER;
2186
2187	err = usb_submit_urb(urb, GFP_ATOMIC);
2188	if (err < 0) {
2189		netdev_err(dev->net, "Error submitting the control"
2190			   " message: status=%d\n", err);
2191		goto fail_free_all;
2192	}
2193	return 0;
2194
2195fail_free_all:
2196	kfree(req);
2197fail_free_buf:
2198	kfree(buf);
2199	/*
2200	 * avoid a double free
2201	 * needed because the flag can be set only
2202	 * after filling the URB
2203	 */
2204	urb->transfer_flags = 0;
2205fail_free_urb:
2206	usb_free_urb(urb);
2207fail:
2208	return err;
2209
2210}
2211EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2212/*-------------------------------------------------------------------------*/
2213
2214static int __init usbnet_init(void)
2215{
2216	/* Compiler should optimize this out. */
2217	BUILD_BUG_ON(
2218		sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2219
2220	eth_random_addr(node_id);
2221	return 0;
2222}
2223module_init(usbnet_init);
2224
2225static void __exit usbnet_exit(void)
2226{
2227}
2228module_exit(usbnet_exit);
2229
2230MODULE_AUTHOR("David Brownell");
2231MODULE_DESCRIPTION("USB network driver framework");
2232MODULE_LICENSE("GPL");