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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * USB Network driver infrastructure
0004  * Copyright (C) 2000-2005 by David Brownell
0005  * Copyright (C) 2003-2005 David Hollis <dhollis@davehollis.com>
0006  */
0007 
0008 /*
0009  * This is a generic "USB networking" framework that works with several
0010  * kinds of full and high speed networking devices:  host-to-host cables,
0011  * smart usb peripherals, and actual Ethernet adapters.
0012  *
0013  * These devices usually differ in terms of control protocols (if they
0014  * even have one!) and sometimes they define new framing to wrap or batch
0015  * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
0016  * so interface (un)binding, endpoint I/O queues, fault handling, and other
0017  * issues can usefully be addressed by this framework.
0018  */
0019 
0020 #include <linux/module.h>
0021 #include <linux/init.h>
0022 #include <linux/netdevice.h>
0023 #include <linux/etherdevice.h>
0024 #include <linux/ctype.h>
0025 #include <linux/ethtool.h>
0026 #include <linux/workqueue.h>
0027 #include <linux/mii.h>
0028 #include <linux/usb.h>
0029 #include <linux/usb/usbnet.h>
0030 #include <linux/slab.h>
0031 #include <linux/kernel.h>
0032 #include <linux/pm_runtime.h>
0033 
0034 /*-------------------------------------------------------------------------*/
0035 
0036 /*
0037  * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
0038  * Several dozen bytes of IPv4 data can fit in two such transactions.
0039  * One maximum size Ethernet packet takes twenty four of them.
0040  * For high speed, each frame comfortably fits almost 36 max size
0041  * Ethernet packets (so queues should be bigger).
0042  *
0043  * The goal is to let the USB host controller be busy for 5msec or
0044  * more before an irq is required, under load.  Jumbograms change
0045  * the equation.
0046  */
0047 #define MAX_QUEUE_MEMORY    (60 * 1518)
0048 #define RX_QLEN(dev)        ((dev)->rx_qlen)
0049 #define TX_QLEN(dev)        ((dev)->tx_qlen)
0050 
0051 // reawaken network queue this soon after stopping; else watchdog barks
0052 #define TX_TIMEOUT_JIFFIES  (5*HZ)
0053 
0054 /* throttle rx/tx briefly after some faults, so hub_wq might disconnect()
0055  * us (it polls at HZ/4 usually) before we report too many false errors.
0056  */
0057 #define THROTTLE_JIFFIES    (HZ/8)
0058 
0059 // between wakeups
0060 #define UNLINK_TIMEOUT_MS   3
0061 
0062 /*-------------------------------------------------------------------------*/
0063 
0064 // randomly generated ethernet address
0065 static u8   node_id [ETH_ALEN];
0066 
0067 /* use ethtool to change the level for any given device */
0068 static int msg_level = -1;
0069 module_param (msg_level, int, 0);
0070 MODULE_PARM_DESC (msg_level, "Override default message level");
0071 
0072 /*-------------------------------------------------------------------------*/
0073 
0074 static const char * const usbnet_event_names[] = {
0075     [EVENT_TX_HALT]        = "EVENT_TX_HALT",
0076     [EVENT_RX_HALT]        = "EVENT_RX_HALT",
0077     [EVENT_RX_MEMORY]      = "EVENT_RX_MEMORY",
0078     [EVENT_STS_SPLIT]      = "EVENT_STS_SPLIT",
0079     [EVENT_LINK_RESET]     = "EVENT_LINK_RESET",
0080     [EVENT_RX_PAUSED]      = "EVENT_RX_PAUSED",
0081     [EVENT_DEV_ASLEEP]     = "EVENT_DEV_ASLEEP",
0082     [EVENT_DEV_OPEN]       = "EVENT_DEV_OPEN",
0083     [EVENT_DEVICE_REPORT_IDLE] = "EVENT_DEVICE_REPORT_IDLE",
0084     [EVENT_NO_RUNTIME_PM]      = "EVENT_NO_RUNTIME_PM",
0085     [EVENT_RX_KILL]        = "EVENT_RX_KILL",
0086     [EVENT_LINK_CHANGE]    = "EVENT_LINK_CHANGE",
0087     [EVENT_SET_RX_MODE]    = "EVENT_SET_RX_MODE",
0088     [EVENT_NO_IP_ALIGN]    = "EVENT_NO_IP_ALIGN",
0089 };
0090 
0091 /* handles CDC Ethernet and many other network "bulk data" interfaces */
0092 int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
0093 {
0094     int             tmp;
0095     struct usb_host_interface   *alt = NULL;
0096     struct usb_host_endpoint    *in = NULL, *out = NULL;
0097     struct usb_host_endpoint    *status = NULL;
0098 
0099     for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
0100         unsigned    ep;
0101 
0102         in = out = status = NULL;
0103         alt = intf->altsetting + tmp;
0104 
0105         /* take the first altsetting with in-bulk + out-bulk;
0106          * remember any status endpoint, just in case;
0107          * ignore other endpoints and altsettings.
0108          */
0109         for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
0110             struct usb_host_endpoint    *e;
0111             int             intr = 0;
0112 
0113             e = alt->endpoint + ep;
0114 
0115             /* ignore endpoints which cannot transfer data */
0116             if (!usb_endpoint_maxp(&e->desc))
0117                 continue;
0118 
0119             switch (e->desc.bmAttributes) {
0120             case USB_ENDPOINT_XFER_INT:
0121                 if (!usb_endpoint_dir_in(&e->desc))
0122                     continue;
0123                 intr = 1;
0124                 fallthrough;
0125             case USB_ENDPOINT_XFER_BULK:
0126                 break;
0127             default:
0128                 continue;
0129             }
0130             if (usb_endpoint_dir_in(&e->desc)) {
0131                 if (!intr && !in)
0132                     in = e;
0133                 else if (intr && !status)
0134                     status = e;
0135             } else {
0136                 if (!out)
0137                     out = e;
0138             }
0139         }
0140         if (in && out)
0141             break;
0142     }
0143     if (!alt || !in || !out)
0144         return -EINVAL;
0145 
0146     if (alt->desc.bAlternateSetting != 0 ||
0147         !(dev->driver_info->flags & FLAG_NO_SETINT)) {
0148         tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
0149                 alt->desc.bAlternateSetting);
0150         if (tmp < 0)
0151             return tmp;
0152     }
0153 
0154     dev->in = usb_rcvbulkpipe (dev->udev,
0155             in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
0156     dev->out = usb_sndbulkpipe (dev->udev,
0157             out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
0158     dev->status = status;
0159     return 0;
0160 }
0161 EXPORT_SYMBOL_GPL(usbnet_get_endpoints);
0162 
0163 int usbnet_get_ethernet_addr(struct usbnet *dev, int iMACAddress)
0164 {
0165     u8      addr[ETH_ALEN];
0166     int         tmp = -1, ret;
0167     unsigned char   buf [13];
0168 
0169     ret = usb_string(dev->udev, iMACAddress, buf, sizeof buf);
0170     if (ret == 12)
0171         tmp = hex2bin(addr, buf, 6);
0172     if (tmp < 0) {
0173         dev_dbg(&dev->udev->dev,
0174             "bad MAC string %d fetch, %d\n", iMACAddress, tmp);
0175         if (ret >= 0)
0176             ret = -EINVAL;
0177         return ret;
0178     }
0179     eth_hw_addr_set(dev->net, addr);
0180     return 0;
0181 }
0182 EXPORT_SYMBOL_GPL(usbnet_get_ethernet_addr);
0183 
0184 static void intr_complete (struct urb *urb)
0185 {
0186     struct usbnet   *dev = urb->context;
0187     int     status = urb->status;
0188 
0189     switch (status) {
0190     /* success */
0191     case 0:
0192         dev->driver_info->status(dev, urb);
0193         break;
0194 
0195     /* software-driven interface shutdown */
0196     case -ENOENT:       /* urb killed */
0197     case -ESHUTDOWN:    /* hardware gone */
0198         netif_dbg(dev, ifdown, dev->net,
0199               "intr shutdown, code %d\n", status);
0200         return;
0201 
0202     /* NOTE:  not throttling like RX/TX, since this endpoint
0203      * already polls infrequently
0204      */
0205     default:
0206         netdev_dbg(dev->net, "intr status %d\n", status);
0207         break;
0208     }
0209 
0210     status = usb_submit_urb (urb, GFP_ATOMIC);
0211     if (status != 0)
0212         netif_err(dev, timer, dev->net,
0213               "intr resubmit --> %d\n", status);
0214 }
0215 
0216 static int init_status (struct usbnet *dev, struct usb_interface *intf)
0217 {
0218     char        *buf = NULL;
0219     unsigned    pipe = 0;
0220     unsigned    maxp;
0221     unsigned    period;
0222 
0223     if (!dev->driver_info->status)
0224         return 0;
0225 
0226     pipe = usb_rcvintpipe (dev->udev,
0227             dev->status->desc.bEndpointAddress
0228                 & USB_ENDPOINT_NUMBER_MASK);
0229     maxp = usb_maxpacket(dev->udev, pipe);
0230 
0231     /* avoid 1 msec chatter:  min 8 msec poll rate */
0232     period = max ((int) dev->status->desc.bInterval,
0233         (dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);
0234 
0235     buf = kmalloc (maxp, GFP_KERNEL);
0236     if (buf) {
0237         dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
0238         if (!dev->interrupt) {
0239             kfree (buf);
0240             return -ENOMEM;
0241         } else {
0242             usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
0243                 buf, maxp, intr_complete, dev, period);
0244             dev->interrupt->transfer_flags |= URB_FREE_BUFFER;
0245             dev_dbg(&intf->dev,
0246                 "status ep%din, %d bytes period %d\n",
0247                 usb_pipeendpoint(pipe), maxp, period);
0248         }
0249     }
0250     return 0;
0251 }
0252 
0253 /* Submit the interrupt URB if not previously submitted, increasing refcount */
0254 int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
0255 {
0256     int ret = 0;
0257 
0258     WARN_ON_ONCE(dev->interrupt == NULL);
0259     if (dev->interrupt) {
0260         mutex_lock(&dev->interrupt_mutex);
0261 
0262         if (++dev->interrupt_count == 1)
0263             ret = usb_submit_urb(dev->interrupt, mem_flags);
0264 
0265         dev_dbg(&dev->udev->dev, "incremented interrupt URB count to %d\n",
0266             dev->interrupt_count);
0267         mutex_unlock(&dev->interrupt_mutex);
0268     }
0269     return ret;
0270 }
0271 EXPORT_SYMBOL_GPL(usbnet_status_start);
0272 
0273 /* For resume; submit interrupt URB if previously submitted */
0274 static int __usbnet_status_start_force(struct usbnet *dev, gfp_t mem_flags)
0275 {
0276     int ret = 0;
0277 
0278     mutex_lock(&dev->interrupt_mutex);
0279     if (dev->interrupt_count) {
0280         ret = usb_submit_urb(dev->interrupt, mem_flags);
0281         dev_dbg(&dev->udev->dev,
0282             "submitted interrupt URB for resume\n");
0283     }
0284     mutex_unlock(&dev->interrupt_mutex);
0285     return ret;
0286 }
0287 
0288 /* Kill the interrupt URB if all submitters want it killed */
0289 void usbnet_status_stop(struct usbnet *dev)
0290 {
0291     if (dev->interrupt) {
0292         mutex_lock(&dev->interrupt_mutex);
0293         WARN_ON(dev->interrupt_count == 0);
0294 
0295         if (dev->interrupt_count && --dev->interrupt_count == 0)
0296             usb_kill_urb(dev->interrupt);
0297 
0298         dev_dbg(&dev->udev->dev,
0299             "decremented interrupt URB count to %d\n",
0300             dev->interrupt_count);
0301         mutex_unlock(&dev->interrupt_mutex);
0302     }
0303 }
0304 EXPORT_SYMBOL_GPL(usbnet_status_stop);
0305 
0306 /* For suspend; always kill interrupt URB */
0307 static void __usbnet_status_stop_force(struct usbnet *dev)
0308 {
0309     if (dev->interrupt) {
0310         mutex_lock(&dev->interrupt_mutex);
0311         usb_kill_urb(dev->interrupt);
0312         dev_dbg(&dev->udev->dev, "killed interrupt URB for suspend\n");
0313         mutex_unlock(&dev->interrupt_mutex);
0314     }
0315 }
0316 
0317 /* Passes this packet up the stack, updating its accounting.
0318  * Some link protocols batch packets, so their rx_fixup paths
0319  * can return clones as well as just modify the original skb.
0320  */
0321 void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
0322 {
0323     struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
0324     unsigned long flags;
0325     int status;
0326 
0327     if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
0328         skb_queue_tail(&dev->rxq_pause, skb);
0329         return;
0330     }
0331 
0332     /* only update if unset to allow minidriver rx_fixup override */
0333     if (skb->protocol == 0)
0334         skb->protocol = eth_type_trans (skb, dev->net);
0335 
0336     flags = u64_stats_update_begin_irqsave(&stats64->syncp);
0337     u64_stats_inc(&stats64->rx_packets);
0338     u64_stats_add(&stats64->rx_bytes, skb->len);
0339     u64_stats_update_end_irqrestore(&stats64->syncp, flags);
0340 
0341     netif_dbg(dev, rx_status, dev->net, "< rx, len %zu, type 0x%x\n",
0342           skb->len + sizeof (struct ethhdr), skb->protocol);
0343     memset (skb->cb, 0, sizeof (struct skb_data));
0344 
0345     if (skb_defer_rx_timestamp(skb))
0346         return;
0347 
0348     status = netif_rx (skb);
0349     if (status != NET_RX_SUCCESS)
0350         netif_dbg(dev, rx_err, dev->net,
0351               "netif_rx status %d\n", status);
0352 }
0353 EXPORT_SYMBOL_GPL(usbnet_skb_return);
0354 
0355 /* must be called if hard_mtu or rx_urb_size changed */
0356 void usbnet_update_max_qlen(struct usbnet *dev)
0357 {
0358     enum usb_device_speed speed = dev->udev->speed;
0359 
0360     if (!dev->rx_urb_size || !dev->hard_mtu)
0361         goto insanity;
0362     switch (speed) {
0363     case USB_SPEED_HIGH:
0364         dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
0365         dev->tx_qlen = MAX_QUEUE_MEMORY / dev->hard_mtu;
0366         break;
0367     case USB_SPEED_SUPER:
0368     case USB_SPEED_SUPER_PLUS:
0369         /*
0370          * Not take default 5ms qlen for super speed HC to
0371          * save memory, and iperf tests show 2.5ms qlen can
0372          * work well
0373          */
0374         dev->rx_qlen = 5 * MAX_QUEUE_MEMORY / dev->rx_urb_size;
0375         dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
0376         break;
0377     default:
0378 insanity:
0379         dev->rx_qlen = dev->tx_qlen = 4;
0380     }
0381 }
0382 EXPORT_SYMBOL_GPL(usbnet_update_max_qlen);
0383 
0384 
0385 /*-------------------------------------------------------------------------
0386  *
0387  * Network Device Driver (peer link to "Host Device", from USB host)
0388  *
0389  *-------------------------------------------------------------------------*/
0390 
0391 int usbnet_change_mtu (struct net_device *net, int new_mtu)
0392 {
0393     struct usbnet   *dev = netdev_priv(net);
0394     int     ll_mtu = new_mtu + net->hard_header_len;
0395     int     old_hard_mtu = dev->hard_mtu;
0396     int     old_rx_urb_size = dev->rx_urb_size;
0397 
0398     // no second zero-length packet read wanted after mtu-sized packets
0399     if ((ll_mtu % dev->maxpacket) == 0)
0400         return -EDOM;
0401     net->mtu = new_mtu;
0402 
0403     dev->hard_mtu = net->mtu + net->hard_header_len;
0404     if (dev->rx_urb_size == old_hard_mtu) {
0405         dev->rx_urb_size = dev->hard_mtu;
0406         if (dev->rx_urb_size > old_rx_urb_size) {
0407             usbnet_pause_rx(dev);
0408             usbnet_unlink_rx_urbs(dev);
0409             usbnet_resume_rx(dev);
0410         }
0411     }
0412 
0413     /* max qlen depend on hard_mtu and rx_urb_size */
0414     usbnet_update_max_qlen(dev);
0415 
0416     return 0;
0417 }
0418 EXPORT_SYMBOL_GPL(usbnet_change_mtu);
0419 
0420 /* The caller must hold list->lock */
0421 static void __usbnet_queue_skb(struct sk_buff_head *list,
0422             struct sk_buff *newsk, enum skb_state state)
0423 {
0424     struct skb_data *entry = (struct skb_data *) newsk->cb;
0425 
0426     __skb_queue_tail(list, newsk);
0427     entry->state = state;
0428 }
0429 
0430 /*-------------------------------------------------------------------------*/
0431 
0432 /* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
0433  * completion callbacks.  2.5 should have fixed those bugs...
0434  */
0435 
0436 static enum skb_state defer_bh(struct usbnet *dev, struct sk_buff *skb,
0437         struct sk_buff_head *list, enum skb_state state)
0438 {
0439     unsigned long       flags;
0440     enum skb_state      old_state;
0441     struct skb_data *entry = (struct skb_data *) skb->cb;
0442 
0443     spin_lock_irqsave(&list->lock, flags);
0444     old_state = entry->state;
0445     entry->state = state;
0446     __skb_unlink(skb, list);
0447 
0448     /* defer_bh() is never called with list == &dev->done.
0449      * spin_lock_nested() tells lockdep that it is OK to take
0450      * dev->done.lock here with list->lock held.
0451      */
0452     spin_lock_nested(&dev->done.lock, SINGLE_DEPTH_NESTING);
0453 
0454     __skb_queue_tail(&dev->done, skb);
0455     if (dev->done.qlen == 1)
0456         tasklet_schedule(&dev->bh);
0457     spin_unlock(&dev->done.lock);
0458     spin_unlock_irqrestore(&list->lock, flags);
0459     return old_state;
0460 }
0461 
0462 /* some work can't be done in tasklets, so we use keventd
0463  *
0464  * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
0465  * but tasklet_schedule() doesn't.  hope the failure is rare.
0466  */
0467 void usbnet_defer_kevent (struct usbnet *dev, int work)
0468 {
0469     set_bit (work, &dev->flags);
0470     if (!schedule_work (&dev->kevent))
0471         netdev_dbg(dev->net, "kevent %s may have been dropped\n", usbnet_event_names[work]);
0472     else
0473         netdev_dbg(dev->net, "kevent %s scheduled\n", usbnet_event_names[work]);
0474 }
0475 EXPORT_SYMBOL_GPL(usbnet_defer_kevent);
0476 
0477 /*-------------------------------------------------------------------------*/
0478 
0479 static void rx_complete (struct urb *urb);
0480 
0481 static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
0482 {
0483     struct sk_buff      *skb;
0484     struct skb_data     *entry;
0485     int         retval = 0;
0486     unsigned long       lockflags;
0487     size_t          size = dev->rx_urb_size;
0488 
0489     /* prevent rx skb allocation when error ratio is high */
0490     if (test_bit(EVENT_RX_KILL, &dev->flags)) {
0491         usb_free_urb(urb);
0492         return -ENOLINK;
0493     }
0494 
0495     if (test_bit(EVENT_NO_IP_ALIGN, &dev->flags))
0496         skb = __netdev_alloc_skb(dev->net, size, flags);
0497     else
0498         skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
0499     if (!skb) {
0500         netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
0501         usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
0502         usb_free_urb (urb);
0503         return -ENOMEM;
0504     }
0505 
0506     entry = (struct skb_data *) skb->cb;
0507     entry->urb = urb;
0508     entry->dev = dev;
0509     entry->length = 0;
0510 
0511     usb_fill_bulk_urb (urb, dev->udev, dev->in,
0512         skb->data, size, rx_complete, skb);
0513 
0514     spin_lock_irqsave (&dev->rxq.lock, lockflags);
0515 
0516     if (netif_running (dev->net) &&
0517         netif_device_present (dev->net) &&
0518         test_bit(EVENT_DEV_OPEN, &dev->flags) &&
0519         !test_bit (EVENT_RX_HALT, &dev->flags) &&
0520         !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) {
0521         switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) {
0522         case -EPIPE:
0523             usbnet_defer_kevent (dev, EVENT_RX_HALT);
0524             break;
0525         case -ENOMEM:
0526             usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
0527             break;
0528         case -ENODEV:
0529             netif_dbg(dev, ifdown, dev->net, "device gone\n");
0530             netif_device_detach (dev->net);
0531             break;
0532         case -EHOSTUNREACH:
0533             retval = -ENOLINK;
0534             break;
0535         default:
0536             netif_dbg(dev, rx_err, dev->net,
0537                   "rx submit, %d\n", retval);
0538             tasklet_schedule (&dev->bh);
0539             break;
0540         case 0:
0541             __usbnet_queue_skb(&dev->rxq, skb, rx_start);
0542         }
0543     } else {
0544         netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");
0545         retval = -ENOLINK;
0546     }
0547     spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
0548     if (retval) {
0549         dev_kfree_skb_any (skb);
0550         usb_free_urb (urb);
0551     }
0552     return retval;
0553 }
0554 
0555 
0556 /*-------------------------------------------------------------------------*/
0557 
0558 static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
0559 {
0560     if (dev->driver_info->rx_fixup &&
0561         !dev->driver_info->rx_fixup (dev, skb)) {
0562         /* With RX_ASSEMBLE, rx_fixup() must update counters */
0563         if (!(dev->driver_info->flags & FLAG_RX_ASSEMBLE))
0564             dev->net->stats.rx_errors++;
0565         goto done;
0566     }
0567     // else network stack removes extra byte if we forced a short packet
0568 
0569     /* all data was already cloned from skb inside the driver */
0570     if (dev->driver_info->flags & FLAG_MULTI_PACKET)
0571         goto done;
0572 
0573     if (skb->len < ETH_HLEN) {
0574         dev->net->stats.rx_errors++;
0575         dev->net->stats.rx_length_errors++;
0576         netif_dbg(dev, rx_err, dev->net, "rx length %d\n", skb->len);
0577     } else {
0578         usbnet_skb_return(dev, skb);
0579         return;
0580     }
0581 
0582 done:
0583     skb_queue_tail(&dev->done, skb);
0584 }
0585 
0586 /*-------------------------------------------------------------------------*/
0587 
0588 static void rx_complete (struct urb *urb)
0589 {
0590     struct sk_buff      *skb = (struct sk_buff *) urb->context;
0591     struct skb_data     *entry = (struct skb_data *) skb->cb;
0592     struct usbnet       *dev = entry->dev;
0593     int         urb_status = urb->status;
0594     enum skb_state      state;
0595 
0596     skb_put (skb, urb->actual_length);
0597     state = rx_done;
0598     entry->urb = NULL;
0599 
0600     switch (urb_status) {
0601     /* success */
0602     case 0:
0603         break;
0604 
0605     /* stalls need manual reset. this is rare ... except that
0606      * when going through USB 2.0 TTs, unplug appears this way.
0607      * we avoid the highspeed version of the ETIMEDOUT/EILSEQ
0608      * storm, recovering as needed.
0609      */
0610     case -EPIPE:
0611         dev->net->stats.rx_errors++;
0612         usbnet_defer_kevent (dev, EVENT_RX_HALT);
0613         fallthrough;
0614 
0615     /* software-driven interface shutdown */
0616     case -ECONNRESET:       /* async unlink */
0617     case -ESHUTDOWN:        /* hardware gone */
0618         netif_dbg(dev, ifdown, dev->net,
0619               "rx shutdown, code %d\n", urb_status);
0620         goto block;
0621 
0622     /* we get controller i/o faults during hub_wq disconnect() delays.
0623      * throttle down resubmits, to avoid log floods; just temporarily,
0624      * so we still recover when the fault isn't a hub_wq delay.
0625      */
0626     case -EPROTO:
0627     case -ETIME:
0628     case -EILSEQ:
0629         dev->net->stats.rx_errors++;
0630         if (!timer_pending (&dev->delay)) {
0631             mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
0632             netif_dbg(dev, link, dev->net,
0633                   "rx throttle %d\n", urb_status);
0634         }
0635 block:
0636         state = rx_cleanup;
0637         entry->urb = urb;
0638         urb = NULL;
0639         break;
0640 
0641     /* data overrun ... flush fifo? */
0642     case -EOVERFLOW:
0643         dev->net->stats.rx_over_errors++;
0644         fallthrough;
0645 
0646     default:
0647         state = rx_cleanup;
0648         dev->net->stats.rx_errors++;
0649         netif_dbg(dev, rx_err, dev->net, "rx status %d\n", urb_status);
0650         break;
0651     }
0652 
0653     /* stop rx if packet error rate is high */
0654     if (++dev->pkt_cnt > 30) {
0655         dev->pkt_cnt = 0;
0656         dev->pkt_err = 0;
0657     } else {
0658         if (state == rx_cleanup)
0659             dev->pkt_err++;
0660         if (dev->pkt_err > 20)
0661             set_bit(EVENT_RX_KILL, &dev->flags);
0662     }
0663 
0664     state = defer_bh(dev, skb, &dev->rxq, state);
0665 
0666     if (urb) {
0667         if (netif_running (dev->net) &&
0668             !test_bit (EVENT_RX_HALT, &dev->flags) &&
0669             state != unlink_start) {
0670             rx_submit (dev, urb, GFP_ATOMIC);
0671             usb_mark_last_busy(dev->udev);
0672             return;
0673         }
0674         usb_free_urb (urb);
0675     }
0676     netif_dbg(dev, rx_err, dev->net, "no read resubmitted\n");
0677 }
0678 
0679 /*-------------------------------------------------------------------------*/
0680 void usbnet_pause_rx(struct usbnet *dev)
0681 {
0682     set_bit(EVENT_RX_PAUSED, &dev->flags);
0683 
0684     netif_dbg(dev, rx_status, dev->net, "paused rx queue enabled\n");
0685 }
0686 EXPORT_SYMBOL_GPL(usbnet_pause_rx);
0687 
0688 void usbnet_resume_rx(struct usbnet *dev)
0689 {
0690     struct sk_buff *skb;
0691     int num = 0;
0692 
0693     clear_bit(EVENT_RX_PAUSED, &dev->flags);
0694 
0695     while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
0696         usbnet_skb_return(dev, skb);
0697         num++;
0698     }
0699 
0700     tasklet_schedule(&dev->bh);
0701 
0702     netif_dbg(dev, rx_status, dev->net,
0703           "paused rx queue disabled, %d skbs requeued\n", num);
0704 }
0705 EXPORT_SYMBOL_GPL(usbnet_resume_rx);
0706 
0707 void usbnet_purge_paused_rxq(struct usbnet *dev)
0708 {
0709     skb_queue_purge(&dev->rxq_pause);
0710 }
0711 EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
0712 
0713 /*-------------------------------------------------------------------------*/
0714 
0715 // unlink pending rx/tx; completion handlers do all other cleanup
0716 
0717 static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q)
0718 {
0719     unsigned long       flags;
0720     struct sk_buff      *skb;
0721     int         count = 0;
0722 
0723     spin_lock_irqsave (&q->lock, flags);
0724     while (!skb_queue_empty(q)) {
0725         struct skb_data     *entry;
0726         struct urb      *urb;
0727         int         retval;
0728 
0729         skb_queue_walk(q, skb) {
0730             entry = (struct skb_data *) skb->cb;
0731             if (entry->state != unlink_start)
0732                 goto found;
0733         }
0734         break;
0735 found:
0736         entry->state = unlink_start;
0737         urb = entry->urb;
0738 
0739         /*
0740          * Get reference count of the URB to avoid it to be
0741          * freed during usb_unlink_urb, which may trigger
0742          * use-after-free problem inside usb_unlink_urb since
0743          * usb_unlink_urb is always racing with .complete
0744          * handler(include defer_bh).
0745          */
0746         usb_get_urb(urb);
0747         spin_unlock_irqrestore(&q->lock, flags);
0748         // during some PM-driven resume scenarios,
0749         // these (async) unlinks complete immediately
0750         retval = usb_unlink_urb (urb);
0751         if (retval != -EINPROGRESS && retval != 0)
0752             netdev_dbg(dev->net, "unlink urb err, %d\n", retval);
0753         else
0754             count++;
0755         usb_put_urb(urb);
0756         spin_lock_irqsave(&q->lock, flags);
0757     }
0758     spin_unlock_irqrestore (&q->lock, flags);
0759     return count;
0760 }
0761 
0762 // Flush all pending rx urbs
0763 // minidrivers may need to do this when the MTU changes
0764 
0765 void usbnet_unlink_rx_urbs(struct usbnet *dev)
0766 {
0767     if (netif_running(dev->net)) {
0768         (void) unlink_urbs (dev, &dev->rxq);
0769         tasklet_schedule(&dev->bh);
0770     }
0771 }
0772 EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
0773 
0774 /*-------------------------------------------------------------------------*/
0775 
0776 static void wait_skb_queue_empty(struct sk_buff_head *q)
0777 {
0778     unsigned long flags;
0779 
0780     spin_lock_irqsave(&q->lock, flags);
0781     while (!skb_queue_empty(q)) {
0782         spin_unlock_irqrestore(&q->lock, flags);
0783         schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
0784         set_current_state(TASK_UNINTERRUPTIBLE);
0785         spin_lock_irqsave(&q->lock, flags);
0786     }
0787     spin_unlock_irqrestore(&q->lock, flags);
0788 }
0789 
0790 // precondition: never called in_interrupt
0791 static void usbnet_terminate_urbs(struct usbnet *dev)
0792 {
0793     DECLARE_WAITQUEUE(wait, current);
0794     int temp;
0795 
0796     /* ensure there are no more active urbs */
0797     add_wait_queue(&dev->wait, &wait);
0798     set_current_state(TASK_UNINTERRUPTIBLE);
0799     temp = unlink_urbs(dev, &dev->txq) +
0800         unlink_urbs(dev, &dev->rxq);
0801 
0802     /* maybe wait for deletions to finish. */
0803     wait_skb_queue_empty(&dev->rxq);
0804     wait_skb_queue_empty(&dev->txq);
0805     wait_skb_queue_empty(&dev->done);
0806     netif_dbg(dev, ifdown, dev->net,
0807           "waited for %d urb completions\n", temp);
0808     set_current_state(TASK_RUNNING);
0809     remove_wait_queue(&dev->wait, &wait);
0810 }
0811 
0812 int usbnet_stop (struct net_device *net)
0813 {
0814     struct usbnet       *dev = netdev_priv(net);
0815     const struct driver_info *info = dev->driver_info;
0816     int         retval, pm, mpn;
0817 
0818     clear_bit(EVENT_DEV_OPEN, &dev->flags);
0819     netif_stop_queue (net);
0820 
0821     netif_info(dev, ifdown, dev->net,
0822            "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
0823            net->stats.rx_packets, net->stats.tx_packets,
0824            net->stats.rx_errors, net->stats.tx_errors);
0825 
0826     /* to not race resume */
0827     pm = usb_autopm_get_interface(dev->intf);
0828     /* allow minidriver to stop correctly (wireless devices to turn off
0829      * radio etc) */
0830     if (info->stop) {
0831         retval = info->stop(dev);
0832         if (retval < 0)
0833             netif_info(dev, ifdown, dev->net,
0834                    "stop fail (%d) usbnet usb-%s-%s, %s\n",
0835                    retval,
0836                    dev->udev->bus->bus_name, dev->udev->devpath,
0837                    info->description);
0838     }
0839 
0840     if (!(info->flags & FLAG_AVOID_UNLINK_URBS))
0841         usbnet_terminate_urbs(dev);
0842 
0843     usbnet_status_stop(dev);
0844 
0845     usbnet_purge_paused_rxq(dev);
0846 
0847     mpn = !test_and_clear_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
0848 
0849     /* deferred work (timer, softirq, task) must also stop */
0850     dev->flags = 0;
0851     del_timer_sync (&dev->delay);
0852     tasklet_kill (&dev->bh);
0853     cancel_work_sync(&dev->kevent);
0854     if (!pm)
0855         usb_autopm_put_interface(dev->intf);
0856 
0857     if (info->manage_power && mpn)
0858         info->manage_power(dev, 0);
0859     else
0860         usb_autopm_put_interface(dev->intf);
0861 
0862     return 0;
0863 }
0864 EXPORT_SYMBOL_GPL(usbnet_stop);
0865 
0866 /*-------------------------------------------------------------------------*/
0867 
0868 // posts reads, and enables write queuing
0869 
0870 // precondition: never called in_interrupt
0871 
0872 int usbnet_open (struct net_device *net)
0873 {
0874     struct usbnet       *dev = netdev_priv(net);
0875     int         retval;
0876     const struct driver_info *info = dev->driver_info;
0877 
0878     if ((retval = usb_autopm_get_interface(dev->intf)) < 0) {
0879         netif_info(dev, ifup, dev->net,
0880                "resumption fail (%d) usbnet usb-%s-%s, %s\n",
0881                retval,
0882                dev->udev->bus->bus_name,
0883                dev->udev->devpath,
0884                info->description);
0885         goto done_nopm;
0886     }
0887 
0888     // put into "known safe" state
0889     if (info->reset && (retval = info->reset (dev)) < 0) {
0890         netif_info(dev, ifup, dev->net,
0891                "open reset fail (%d) usbnet usb-%s-%s, %s\n",
0892                retval,
0893                dev->udev->bus->bus_name,
0894                dev->udev->devpath,
0895                info->description);
0896         goto done;
0897     }
0898 
0899     /* hard_mtu or rx_urb_size may change in reset() */
0900     usbnet_update_max_qlen(dev);
0901 
0902     // insist peer be connected
0903     if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
0904         netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
0905         goto done;
0906     }
0907 
0908     /* start any status interrupt transfer */
0909     if (dev->interrupt) {
0910         retval = usbnet_status_start(dev, GFP_KERNEL);
0911         if (retval < 0) {
0912             netif_err(dev, ifup, dev->net,
0913                   "intr submit %d\n", retval);
0914             goto done;
0915         }
0916     }
0917 
0918     set_bit(EVENT_DEV_OPEN, &dev->flags);
0919     netif_start_queue (net);
0920     netif_info(dev, ifup, dev->net,
0921            "open: enable queueing (rx %d, tx %d) mtu %d %s framing\n",
0922            (int)RX_QLEN(dev), (int)TX_QLEN(dev),
0923            dev->net->mtu,
0924            (dev->driver_info->flags & FLAG_FRAMING_NC) ? "NetChip" :
0925            (dev->driver_info->flags & FLAG_FRAMING_GL) ? "GeneSys" :
0926            (dev->driver_info->flags & FLAG_FRAMING_Z) ? "Zaurus" :
0927            (dev->driver_info->flags & FLAG_FRAMING_RN) ? "RNDIS" :
0928            (dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
0929            "simple");
0930 
0931     /* reset rx error state */
0932     dev->pkt_cnt = 0;
0933     dev->pkt_err = 0;
0934     clear_bit(EVENT_RX_KILL, &dev->flags);
0935 
0936     // delay posting reads until we're fully open
0937     tasklet_schedule (&dev->bh);
0938     if (info->manage_power) {
0939         retval = info->manage_power(dev, 1);
0940         if (retval < 0) {
0941             retval = 0;
0942             set_bit(EVENT_NO_RUNTIME_PM, &dev->flags);
0943         } else {
0944             usb_autopm_put_interface(dev->intf);
0945         }
0946     }
0947     return retval;
0948 done:
0949     usb_autopm_put_interface(dev->intf);
0950 done_nopm:
0951     return retval;
0952 }
0953 EXPORT_SYMBOL_GPL(usbnet_open);
0954 
0955 /*-------------------------------------------------------------------------*/
0956 
0957 /* ethtool methods; minidrivers may need to add some more, but
0958  * they'll probably want to use this base set.
0959  */
0960 
0961 /* These methods are written on the assumption that the device
0962  * uses MII
0963  */
0964 int usbnet_get_link_ksettings_mii(struct net_device *net,
0965                   struct ethtool_link_ksettings *cmd)
0966 {
0967     struct usbnet *dev = netdev_priv(net);
0968 
0969     if (!dev->mii.mdio_read)
0970         return -EOPNOTSUPP;
0971 
0972     mii_ethtool_get_link_ksettings(&dev->mii, cmd);
0973 
0974     return 0;
0975 }
0976 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_mii);
0977 
0978 int usbnet_get_link_ksettings_internal(struct net_device *net,
0979                     struct ethtool_link_ksettings *cmd)
0980 {
0981     struct usbnet *dev = netdev_priv(net);
0982 
0983     /* the assumption that speed is equal on tx and rx
0984      * is deeply engrained into the networking layer.
0985      * For wireless stuff it is not true.
0986      * We assume that rx_speed matters more.
0987      */
0988     if (dev->rx_speed != SPEED_UNSET)
0989         cmd->base.speed = dev->rx_speed / 1000000;
0990     else if (dev->tx_speed != SPEED_UNSET)
0991         cmd->base.speed = dev->tx_speed / 1000000;
0992     else
0993         cmd->base.speed = SPEED_UNKNOWN;
0994 
0995     return 0;
0996 }
0997 EXPORT_SYMBOL_GPL(usbnet_get_link_ksettings_internal);
0998 
0999 int usbnet_set_link_ksettings_mii(struct net_device *net,
1000                   const struct ethtool_link_ksettings *cmd)
1001 {
1002     struct usbnet *dev = netdev_priv(net);
1003     int retval;
1004 
1005     if (!dev->mii.mdio_write)
1006         return -EOPNOTSUPP;
1007 
1008     retval = mii_ethtool_set_link_ksettings(&dev->mii, cmd);
1009 
1010     /* link speed/duplex might have changed */
1011     if (dev->driver_info->link_reset)
1012         dev->driver_info->link_reset(dev);
1013 
1014     /* hard_mtu or rx_urb_size may change in link_reset() */
1015     usbnet_update_max_qlen(dev);
1016 
1017     return retval;
1018 }
1019 EXPORT_SYMBOL_GPL(usbnet_set_link_ksettings_mii);
1020 
1021 u32 usbnet_get_link (struct net_device *net)
1022 {
1023     struct usbnet *dev = netdev_priv(net);
1024 
1025     /* If a check_connect is defined, return its result */
1026     if (dev->driver_info->check_connect)
1027         return dev->driver_info->check_connect (dev) == 0;
1028 
1029     /* if the device has mii operations, use those */
1030     if (dev->mii.mdio_read)
1031         return mii_link_ok(&dev->mii);
1032 
1033     /* Otherwise, dtrt for drivers calling netif_carrier_{on,off} */
1034     return ethtool_op_get_link(net);
1035 }
1036 EXPORT_SYMBOL_GPL(usbnet_get_link);
1037 
1038 int usbnet_nway_reset(struct net_device *net)
1039 {
1040     struct usbnet *dev = netdev_priv(net);
1041 
1042     if (!dev->mii.mdio_write)
1043         return -EOPNOTSUPP;
1044 
1045     return mii_nway_restart(&dev->mii);
1046 }
1047 EXPORT_SYMBOL_GPL(usbnet_nway_reset);
1048 
1049 void usbnet_get_drvinfo (struct net_device *net, struct ethtool_drvinfo *info)
1050 {
1051     struct usbnet *dev = netdev_priv(net);
1052 
1053     strlcpy (info->driver, dev->driver_name, sizeof info->driver);
1054     strlcpy (info->fw_version, dev->driver_info->description,
1055         sizeof info->fw_version);
1056     usb_make_path (dev->udev, info->bus_info, sizeof info->bus_info);
1057 }
1058 EXPORT_SYMBOL_GPL(usbnet_get_drvinfo);
1059 
1060 u32 usbnet_get_msglevel (struct net_device *net)
1061 {
1062     struct usbnet *dev = netdev_priv(net);
1063 
1064     return dev->msg_enable;
1065 }
1066 EXPORT_SYMBOL_GPL(usbnet_get_msglevel);
1067 
1068 void usbnet_set_msglevel (struct net_device *net, u32 level)
1069 {
1070     struct usbnet *dev = netdev_priv(net);
1071 
1072     dev->msg_enable = level;
1073 }
1074 EXPORT_SYMBOL_GPL(usbnet_set_msglevel);
1075 
1076 /* drivers may override default ethtool_ops in their bind() routine */
1077 static const struct ethtool_ops usbnet_ethtool_ops = {
1078     .get_link       = usbnet_get_link,
1079     .nway_reset     = usbnet_nway_reset,
1080     .get_drvinfo        = usbnet_get_drvinfo,
1081     .get_msglevel       = usbnet_get_msglevel,
1082     .set_msglevel       = usbnet_set_msglevel,
1083     .get_ts_info        = ethtool_op_get_ts_info,
1084     .get_link_ksettings = usbnet_get_link_ksettings_mii,
1085     .set_link_ksettings = usbnet_set_link_ksettings_mii,
1086 };
1087 
1088 /*-------------------------------------------------------------------------*/
1089 
1090 static void __handle_link_change(struct usbnet *dev)
1091 {
1092     if (!test_bit(EVENT_DEV_OPEN, &dev->flags))
1093         return;
1094 
1095     if (!netif_carrier_ok(dev->net)) {
1096         /* kill URBs for reading packets to save bus bandwidth */
1097         unlink_urbs(dev, &dev->rxq);
1098 
1099         /*
1100          * tx_timeout will unlink URBs for sending packets and
1101          * tx queue is stopped by netcore after link becomes off
1102          */
1103     } else {
1104         /* submitting URBs for reading packets */
1105         tasklet_schedule(&dev->bh);
1106     }
1107 
1108     /* hard_mtu or rx_urb_size may change during link change */
1109     usbnet_update_max_qlen(dev);
1110 
1111     clear_bit(EVENT_LINK_CHANGE, &dev->flags);
1112 }
1113 
1114 void usbnet_set_rx_mode(struct net_device *net)
1115 {
1116     struct usbnet       *dev = netdev_priv(net);
1117 
1118     usbnet_defer_kevent(dev, EVENT_SET_RX_MODE);
1119 }
1120 EXPORT_SYMBOL_GPL(usbnet_set_rx_mode);
1121 
1122 static void __handle_set_rx_mode(struct usbnet *dev)
1123 {
1124     if (dev->driver_info->set_rx_mode)
1125         (dev->driver_info->set_rx_mode)(dev);
1126 
1127     clear_bit(EVENT_SET_RX_MODE, &dev->flags);
1128 }
1129 
1130 /* work that cannot be done in interrupt context uses keventd.
1131  *
1132  * NOTE:  with 2.5 we could do more of this using completion callbacks,
1133  * especially now that control transfers can be queued.
1134  */
1135 static void
1136 usbnet_deferred_kevent (struct work_struct *work)
1137 {
1138     struct usbnet       *dev =
1139         container_of(work, struct usbnet, kevent);
1140     int         status;
1141 
1142     /* usb_clear_halt() needs a thread context */
1143     if (test_bit (EVENT_TX_HALT, &dev->flags)) {
1144         unlink_urbs (dev, &dev->txq);
1145         status = usb_autopm_get_interface(dev->intf);
1146         if (status < 0)
1147             goto fail_pipe;
1148         status = usb_clear_halt (dev->udev, dev->out);
1149         usb_autopm_put_interface(dev->intf);
1150         if (status < 0 &&
1151             status != -EPIPE &&
1152             status != -ESHUTDOWN) {
1153             if (netif_msg_tx_err (dev))
1154 fail_pipe:
1155                 netdev_err(dev->net, "can't clear tx halt, status %d\n",
1156                        status);
1157         } else {
1158             clear_bit (EVENT_TX_HALT, &dev->flags);
1159             if (status != -ESHUTDOWN)
1160                 netif_wake_queue (dev->net);
1161         }
1162     }
1163     if (test_bit (EVENT_RX_HALT, &dev->flags)) {
1164         unlink_urbs (dev, &dev->rxq);
1165         status = usb_autopm_get_interface(dev->intf);
1166         if (status < 0)
1167             goto fail_halt;
1168         status = usb_clear_halt (dev->udev, dev->in);
1169         usb_autopm_put_interface(dev->intf);
1170         if (status < 0 &&
1171             status != -EPIPE &&
1172             status != -ESHUTDOWN) {
1173             if (netif_msg_rx_err (dev))
1174 fail_halt:
1175                 netdev_err(dev->net, "can't clear rx halt, status %d\n",
1176                        status);
1177         } else {
1178             clear_bit (EVENT_RX_HALT, &dev->flags);
1179             tasklet_schedule (&dev->bh);
1180         }
1181     }
1182 
1183     /* tasklet could resubmit itself forever if memory is tight */
1184     if (test_bit (EVENT_RX_MEMORY, &dev->flags)) {
1185         struct urb  *urb = NULL;
1186         int resched = 1;
1187 
1188         if (netif_running (dev->net))
1189             urb = usb_alloc_urb (0, GFP_KERNEL);
1190         else
1191             clear_bit (EVENT_RX_MEMORY, &dev->flags);
1192         if (urb != NULL) {
1193             clear_bit (EVENT_RX_MEMORY, &dev->flags);
1194             status = usb_autopm_get_interface(dev->intf);
1195             if (status < 0) {
1196                 usb_free_urb(urb);
1197                 goto fail_lowmem;
1198             }
1199             if (rx_submit (dev, urb, GFP_KERNEL) == -ENOLINK)
1200                 resched = 0;
1201             usb_autopm_put_interface(dev->intf);
1202 fail_lowmem:
1203             if (resched)
1204                 tasklet_schedule (&dev->bh);
1205         }
1206     }
1207 
1208     if (test_bit (EVENT_LINK_RESET, &dev->flags)) {
1209         const struct driver_info *info = dev->driver_info;
1210         int         retval = 0;
1211 
1212         clear_bit (EVENT_LINK_RESET, &dev->flags);
1213         status = usb_autopm_get_interface(dev->intf);
1214         if (status < 0)
1215             goto skip_reset;
1216         if(info->link_reset && (retval = info->link_reset(dev)) < 0) {
1217             usb_autopm_put_interface(dev->intf);
1218 skip_reset:
1219             netdev_info(dev->net, "link reset failed (%d) usbnet usb-%s-%s, %s\n",
1220                     retval,
1221                     dev->udev->bus->bus_name,
1222                     dev->udev->devpath,
1223                     info->description);
1224         } else {
1225             usb_autopm_put_interface(dev->intf);
1226         }
1227 
1228         /* handle link change from link resetting */
1229         __handle_link_change(dev);
1230     }
1231 
1232     if (test_bit (EVENT_LINK_CHANGE, &dev->flags))
1233         __handle_link_change(dev);
1234 
1235     if (test_bit (EVENT_SET_RX_MODE, &dev->flags))
1236         __handle_set_rx_mode(dev);
1237 
1238 
1239     if (dev->flags)
1240         netdev_dbg(dev->net, "kevent done, flags = 0x%lx\n", dev->flags);
1241 }
1242 
1243 /*-------------------------------------------------------------------------*/
1244 
1245 static void tx_complete (struct urb *urb)
1246 {
1247     struct sk_buff      *skb = (struct sk_buff *) urb->context;
1248     struct skb_data     *entry = (struct skb_data *) skb->cb;
1249     struct usbnet       *dev = entry->dev;
1250 
1251     if (urb->status == 0) {
1252         struct pcpu_sw_netstats *stats64 = this_cpu_ptr(dev->net->tstats);
1253         unsigned long flags;
1254 
1255         flags = u64_stats_update_begin_irqsave(&stats64->syncp);
1256         u64_stats_add(&stats64->tx_packets, entry->packets);
1257         u64_stats_add(&stats64->tx_bytes, entry->length);
1258         u64_stats_update_end_irqrestore(&stats64->syncp, flags);
1259     } else {
1260         dev->net->stats.tx_errors++;
1261 
1262         switch (urb->status) {
1263         case -EPIPE:
1264             usbnet_defer_kevent (dev, EVENT_TX_HALT);
1265             break;
1266 
1267         /* software-driven interface shutdown */
1268         case -ECONNRESET:       // async unlink
1269         case -ESHUTDOWN:        // hardware gone
1270             break;
1271 
1272         /* like rx, tx gets controller i/o faults during hub_wq
1273          * delays and so it uses the same throttling mechanism.
1274          */
1275         case -EPROTO:
1276         case -ETIME:
1277         case -EILSEQ:
1278             usb_mark_last_busy(dev->udev);
1279             if (!timer_pending (&dev->delay)) {
1280                 mod_timer (&dev->delay,
1281                     jiffies + THROTTLE_JIFFIES);
1282                 netif_dbg(dev, link, dev->net,
1283                       "tx throttle %d\n", urb->status);
1284             }
1285             netif_stop_queue (dev->net);
1286             break;
1287         default:
1288             netif_dbg(dev, tx_err, dev->net,
1289                   "tx err %d\n", entry->urb->status);
1290             break;
1291         }
1292     }
1293 
1294     usb_autopm_put_interface_async(dev->intf);
1295     (void) defer_bh(dev, skb, &dev->txq, tx_done);
1296 }
1297 
1298 /*-------------------------------------------------------------------------*/
1299 
1300 void usbnet_tx_timeout (struct net_device *net, unsigned int txqueue)
1301 {
1302     struct usbnet       *dev = netdev_priv(net);
1303 
1304     unlink_urbs (dev, &dev->txq);
1305     tasklet_schedule (&dev->bh);
1306     /* this needs to be handled individually because the generic layer
1307      * doesn't know what is sufficient and could not restore private
1308      * information if a remedy of an unconditional reset were used.
1309      */
1310     if (dev->driver_info->recover)
1311         (dev->driver_info->recover)(dev);
1312 }
1313 EXPORT_SYMBOL_GPL(usbnet_tx_timeout);
1314 
1315 /*-------------------------------------------------------------------------*/
1316 
1317 static int build_dma_sg(const struct sk_buff *skb, struct urb *urb)
1318 {
1319     unsigned num_sgs, total_len = 0;
1320     int i, s = 0;
1321 
1322     num_sgs = skb_shinfo(skb)->nr_frags + 1;
1323     if (num_sgs == 1)
1324         return 0;
1325 
1326     /* reserve one for zero packet */
1327     urb->sg = kmalloc_array(num_sgs + 1, sizeof(struct scatterlist),
1328                 GFP_ATOMIC);
1329     if (!urb->sg)
1330         return -ENOMEM;
1331 
1332     urb->num_sgs = num_sgs;
1333     sg_init_table(urb->sg, urb->num_sgs + 1);
1334 
1335     sg_set_buf(&urb->sg[s++], skb->data, skb_headlen(skb));
1336     total_len += skb_headlen(skb);
1337 
1338     for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
1339         skb_frag_t *f = &skb_shinfo(skb)->frags[i];
1340 
1341         total_len += skb_frag_size(f);
1342         sg_set_page(&urb->sg[i + s], skb_frag_page(f), skb_frag_size(f),
1343                 skb_frag_off(f));
1344     }
1345     urb->transfer_buffer_length = total_len;
1346 
1347     return 1;
1348 }
1349 
1350 netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
1351                      struct net_device *net)
1352 {
1353     struct usbnet       *dev = netdev_priv(net);
1354     unsigned int            length;
1355     struct urb      *urb = NULL;
1356     struct skb_data     *entry;
1357     const struct driver_info *info = dev->driver_info;
1358     unsigned long       flags;
1359     int retval;
1360 
1361     if (skb)
1362         skb_tx_timestamp(skb);
1363 
1364     // some devices want funky USB-level framing, for
1365     // win32 driver (usually) and/or hardware quirks
1366     if (info->tx_fixup) {
1367         skb = info->tx_fixup (dev, skb, GFP_ATOMIC);
1368         if (!skb) {
1369             /* packet collected; minidriver waiting for more */
1370             if (info->flags & FLAG_MULTI_PACKET)
1371                 goto not_drop;
1372             netif_dbg(dev, tx_err, dev->net, "can't tx_fixup skb\n");
1373             goto drop;
1374         }
1375     }
1376 
1377     if (!(urb = usb_alloc_urb (0, GFP_ATOMIC))) {
1378         netif_dbg(dev, tx_err, dev->net, "no urb\n");
1379         goto drop;
1380     }
1381 
1382     entry = (struct skb_data *) skb->cb;
1383     entry->urb = urb;
1384     entry->dev = dev;
1385 
1386     usb_fill_bulk_urb (urb, dev->udev, dev->out,
1387             skb->data, skb->len, tx_complete, skb);
1388     if (dev->can_dma_sg) {
1389         if (build_dma_sg(skb, urb) < 0)
1390             goto drop;
1391     }
1392     length = urb->transfer_buffer_length;
1393 
1394     /* don't assume the hardware handles USB_ZERO_PACKET
1395      * NOTE:  strictly conforming cdc-ether devices should expect
1396      * the ZLP here, but ignore the one-byte packet.
1397      * NOTE2: CDC NCM specification is different from CDC ECM when
1398      * handling ZLP/short packets, so cdc_ncm driver will make short
1399      * packet itself if needed.
1400      */
1401     if (length % dev->maxpacket == 0) {
1402         if (!(info->flags & FLAG_SEND_ZLP)) {
1403             if (!(info->flags & FLAG_MULTI_PACKET)) {
1404                 length++;
1405                 if (skb_tailroom(skb) && !urb->num_sgs) {
1406                     skb->data[skb->len] = 0;
1407                     __skb_put(skb, 1);
1408                 } else if (urb->num_sgs)
1409                     sg_set_buf(&urb->sg[urb->num_sgs++],
1410                             dev->padding_pkt, 1);
1411             }
1412         } else
1413             urb->transfer_flags |= URB_ZERO_PACKET;
1414     }
1415     urb->transfer_buffer_length = length;
1416 
1417     if (info->flags & FLAG_MULTI_PACKET) {
1418         /* Driver has set number of packets and a length delta.
1419          * Calculate the complete length and ensure that it's
1420          * positive.
1421          */
1422         entry->length += length;
1423         if (WARN_ON_ONCE(entry->length <= 0))
1424             entry->length = length;
1425     } else {
1426         usbnet_set_skb_tx_stats(skb, 1, length);
1427     }
1428 
1429     spin_lock_irqsave(&dev->txq.lock, flags);
1430     retval = usb_autopm_get_interface_async(dev->intf);
1431     if (retval < 0) {
1432         spin_unlock_irqrestore(&dev->txq.lock, flags);
1433         goto drop;
1434     }
1435     if (netif_queue_stopped(net)) {
1436         usb_autopm_put_interface_async(dev->intf);
1437         spin_unlock_irqrestore(&dev->txq.lock, flags);
1438         goto drop;
1439     }
1440 
1441 #ifdef CONFIG_PM
1442     /* if this triggers the device is still a sleep */
1443     if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
1444         /* transmission will be done in resume */
1445         usb_anchor_urb(urb, &dev->deferred);
1446         /* no use to process more packets */
1447         netif_stop_queue(net);
1448         usb_put_urb(urb);
1449         spin_unlock_irqrestore(&dev->txq.lock, flags);
1450         netdev_dbg(dev->net, "Delaying transmission for resumption\n");
1451         goto deferred;
1452     }
1453 #endif
1454 
1455     switch ((retval = usb_submit_urb (urb, GFP_ATOMIC))) {
1456     case -EPIPE:
1457         netif_stop_queue (net);
1458         usbnet_defer_kevent (dev, EVENT_TX_HALT);
1459         usb_autopm_put_interface_async(dev->intf);
1460         break;
1461     default:
1462         usb_autopm_put_interface_async(dev->intf);
1463         netif_dbg(dev, tx_err, dev->net,
1464               "tx: submit urb err %d\n", retval);
1465         break;
1466     case 0:
1467         netif_trans_update(net);
1468         __usbnet_queue_skb(&dev->txq, skb, tx_start);
1469         if (dev->txq.qlen >= TX_QLEN (dev))
1470             netif_stop_queue (net);
1471     }
1472     spin_unlock_irqrestore (&dev->txq.lock, flags);
1473 
1474     if (retval) {
1475         netif_dbg(dev, tx_err, dev->net, "drop, code %d\n", retval);
1476 drop:
1477         dev->net->stats.tx_dropped++;
1478 not_drop:
1479         if (skb)
1480             dev_kfree_skb_any (skb);
1481         if (urb) {
1482             kfree(urb->sg);
1483             usb_free_urb(urb);
1484         }
1485     } else
1486         netif_dbg(dev, tx_queued, dev->net,
1487               "> tx, len %u, type 0x%x\n", length, skb->protocol);
1488 #ifdef CONFIG_PM
1489 deferred:
1490 #endif
1491     return NETDEV_TX_OK;
1492 }
1493 EXPORT_SYMBOL_GPL(usbnet_start_xmit);
1494 
1495 static int rx_alloc_submit(struct usbnet *dev, gfp_t flags)
1496 {
1497     struct urb  *urb;
1498     int     i;
1499     int     ret = 0;
1500 
1501     /* don't refill the queue all at once */
1502     for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) {
1503         urb = usb_alloc_urb(0, flags);
1504         if (urb != NULL) {
1505             ret = rx_submit(dev, urb, flags);
1506             if (ret)
1507                 goto err;
1508         } else {
1509             ret = -ENOMEM;
1510             goto err;
1511         }
1512     }
1513 err:
1514     return ret;
1515 }
1516 
1517 /*-------------------------------------------------------------------------*/
1518 
1519 // tasklet (work deferred from completions, in_irq) or timer
1520 
1521 static void usbnet_bh (struct timer_list *t)
1522 {
1523     struct usbnet       *dev = from_timer(dev, t, delay);
1524     struct sk_buff      *skb;
1525     struct skb_data     *entry;
1526 
1527     while ((skb = skb_dequeue (&dev->done))) {
1528         entry = (struct skb_data *) skb->cb;
1529         switch (entry->state) {
1530         case rx_done:
1531             entry->state = rx_cleanup;
1532             rx_process (dev, skb);
1533             continue;
1534         case tx_done:
1535             kfree(entry->urb->sg);
1536             fallthrough;
1537         case rx_cleanup:
1538             usb_free_urb (entry->urb);
1539             dev_kfree_skb (skb);
1540             continue;
1541         default:
1542             netdev_dbg(dev->net, "bogus skb state %d\n", entry->state);
1543         }
1544     }
1545 
1546     /* restart RX again after disabling due to high error rate */
1547     clear_bit(EVENT_RX_KILL, &dev->flags);
1548 
1549     /* waiting for all pending urbs to complete?
1550      * only then can we forgo submitting anew
1551      */
1552     if (waitqueue_active(&dev->wait)) {
1553         if (dev->txq.qlen + dev->rxq.qlen + dev->done.qlen == 0)
1554             wake_up_all(&dev->wait);
1555 
1556     // or are we maybe short a few urbs?
1557     } else if (netif_running (dev->net) &&
1558            netif_device_present (dev->net) &&
1559            netif_carrier_ok(dev->net) &&
1560            !timer_pending(&dev->delay) &&
1561            !test_bit(EVENT_RX_PAUSED, &dev->flags) &&
1562            !test_bit(EVENT_RX_HALT, &dev->flags)) {
1563         int temp = dev->rxq.qlen;
1564 
1565         if (temp < RX_QLEN(dev)) {
1566             if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK)
1567                 return;
1568             if (temp != dev->rxq.qlen)
1569                 netif_dbg(dev, link, dev->net,
1570                       "rxqlen %d --> %d\n",
1571                       temp, dev->rxq.qlen);
1572             if (dev->rxq.qlen < RX_QLEN(dev))
1573                 tasklet_schedule (&dev->bh);
1574         }
1575         if (dev->txq.qlen < TX_QLEN (dev))
1576             netif_wake_queue (dev->net);
1577     }
1578 }
1579 
1580 static void usbnet_bh_tasklet(struct tasklet_struct *t)
1581 {
1582     struct usbnet *dev = from_tasklet(dev, t, bh);
1583 
1584     usbnet_bh(&dev->delay);
1585 }
1586 
1587 
1588 /*-------------------------------------------------------------------------
1589  *
1590  * USB Device Driver support
1591  *
1592  *-------------------------------------------------------------------------*/
1593 
1594 // precondition: never called in_interrupt
1595 
1596 void usbnet_disconnect (struct usb_interface *intf)
1597 {
1598     struct usbnet       *dev;
1599     struct usb_device   *xdev;
1600     struct net_device   *net;
1601     struct urb      *urb;
1602 
1603     dev = usb_get_intfdata(intf);
1604     usb_set_intfdata(intf, NULL);
1605     if (!dev)
1606         return;
1607 
1608     xdev = interface_to_usbdev (intf);
1609 
1610     netif_info(dev, probe, dev->net, "unregister '%s' usb-%s-%s, %s\n",
1611            intf->dev.driver->name,
1612            xdev->bus->bus_name, xdev->devpath,
1613            dev->driver_info->description);
1614 
1615     net = dev->net;
1616     unregister_netdev (net);
1617 
1618     while ((urb = usb_get_from_anchor(&dev->deferred))) {
1619         dev_kfree_skb(urb->context);
1620         kfree(urb->sg);
1621         usb_free_urb(urb);
1622     }
1623 
1624     if (dev->driver_info->unbind)
1625         dev->driver_info->unbind(dev, intf);
1626 
1627     usb_kill_urb(dev->interrupt);
1628     usb_free_urb(dev->interrupt);
1629     kfree(dev->padding_pkt);
1630 
1631     free_percpu(net->tstats);
1632     free_netdev(net);
1633 }
1634 EXPORT_SYMBOL_GPL(usbnet_disconnect);
1635 
1636 static const struct net_device_ops usbnet_netdev_ops = {
1637     .ndo_open       = usbnet_open,
1638     .ndo_stop       = usbnet_stop,
1639     .ndo_start_xmit     = usbnet_start_xmit,
1640     .ndo_tx_timeout     = usbnet_tx_timeout,
1641     .ndo_set_rx_mode    = usbnet_set_rx_mode,
1642     .ndo_change_mtu     = usbnet_change_mtu,
1643     .ndo_get_stats64    = dev_get_tstats64,
1644     .ndo_set_mac_address    = eth_mac_addr,
1645     .ndo_validate_addr  = eth_validate_addr,
1646 };
1647 
1648 /*-------------------------------------------------------------------------*/
1649 
1650 // precondition: never called in_interrupt
1651 
1652 static struct device_type wlan_type = {
1653     .name   = "wlan",
1654 };
1655 
1656 static struct device_type wwan_type = {
1657     .name   = "wwan",
1658 };
1659 
1660 int
1661 usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
1662 {
1663     struct usbnet           *dev;
1664     struct net_device       *net;
1665     struct usb_host_interface   *interface;
1666     const struct driver_info    *info;
1667     struct usb_device       *xdev;
1668     int             status;
1669     const char          *name;
1670     struct usb_driver   *driver = to_usb_driver(udev->dev.driver);
1671 
1672     /* usbnet already took usb runtime pm, so have to enable the feature
1673      * for usb interface, otherwise usb_autopm_get_interface may return
1674      * failure if RUNTIME_PM is enabled.
1675      */
1676     if (!driver->supports_autosuspend) {
1677         driver->supports_autosuspend = 1;
1678         pm_runtime_enable(&udev->dev);
1679     }
1680 
1681     name = udev->dev.driver->name;
1682     info = (const struct driver_info *) prod->driver_info;
1683     if (!info) {
1684         dev_dbg (&udev->dev, "blacklisted by %s\n", name);
1685         return -ENODEV;
1686     }
1687     xdev = interface_to_usbdev (udev);
1688     interface = udev->cur_altsetting;
1689 
1690     status = -ENOMEM;
1691 
1692     // set up our own records
1693     net = alloc_etherdev(sizeof(*dev));
1694     if (!net)
1695         goto out;
1696 
1697     /* netdev_printk() needs this so do it as early as possible */
1698     SET_NETDEV_DEV(net, &udev->dev);
1699 
1700     dev = netdev_priv(net);
1701     dev->udev = xdev;
1702     dev->intf = udev;
1703     dev->driver_info = info;
1704     dev->driver_name = name;
1705     dev->rx_speed = SPEED_UNSET;
1706     dev->tx_speed = SPEED_UNSET;
1707 
1708     net->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1709     if (!net->tstats)
1710         goto out0;
1711 
1712     dev->msg_enable = netif_msg_init (msg_level, NETIF_MSG_DRV
1713                 | NETIF_MSG_PROBE | NETIF_MSG_LINK);
1714     init_waitqueue_head(&dev->wait);
1715     skb_queue_head_init (&dev->rxq);
1716     skb_queue_head_init (&dev->txq);
1717     skb_queue_head_init (&dev->done);
1718     skb_queue_head_init(&dev->rxq_pause);
1719     tasklet_setup(&dev->bh, usbnet_bh_tasklet);
1720     INIT_WORK (&dev->kevent, usbnet_deferred_kevent);
1721     init_usb_anchor(&dev->deferred);
1722     timer_setup(&dev->delay, usbnet_bh, 0);
1723     mutex_init (&dev->phy_mutex);
1724     mutex_init(&dev->interrupt_mutex);
1725     dev->interrupt_count = 0;
1726 
1727     dev->net = net;
1728     strscpy(net->name, "usb%d", sizeof(net->name));
1729     eth_hw_addr_set(net, node_id);
1730 
1731     /* rx and tx sides can use different message sizes;
1732      * bind() should set rx_urb_size in that case.
1733      */
1734     dev->hard_mtu = net->mtu + net->hard_header_len;
1735     net->min_mtu = 0;
1736     net->max_mtu = ETH_MAX_MTU;
1737 
1738     net->netdev_ops = &usbnet_netdev_ops;
1739     net->watchdog_timeo = TX_TIMEOUT_JIFFIES;
1740     net->ethtool_ops = &usbnet_ethtool_ops;
1741 
1742     // allow device-specific bind/init procedures
1743     // NOTE net->name still not usable ...
1744     if (info->bind) {
1745         status = info->bind (dev, udev);
1746         if (status < 0)
1747             goto out1;
1748 
1749         // heuristic:  "usb%d" for links we know are two-host,
1750         // else "eth%d" when there's reasonable doubt.  userspace
1751         // can rename the link if it knows better.
1752         if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
1753             ((dev->driver_info->flags & FLAG_POINTTOPOINT) == 0 ||
1754              (net->dev_addr [0] & 0x02) == 0))
1755             strscpy(net->name, "eth%d", sizeof(net->name));
1756         /* WLAN devices should always be named "wlan%d" */
1757         if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1758             strscpy(net->name, "wlan%d", sizeof(net->name));
1759         /* WWAN devices should always be named "wwan%d" */
1760         if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1761             strscpy(net->name, "wwan%d", sizeof(net->name));
1762 
1763         /* devices that cannot do ARP */
1764         if ((dev->driver_info->flags & FLAG_NOARP) != 0)
1765             net->flags |= IFF_NOARP;
1766 
1767         /* maybe the remote can't receive an Ethernet MTU */
1768         if (net->mtu > (dev->hard_mtu - net->hard_header_len))
1769             net->mtu = dev->hard_mtu - net->hard_header_len;
1770     } else if (!info->in || !info->out)
1771         status = usbnet_get_endpoints (dev, udev);
1772     else {
1773         dev->in = usb_rcvbulkpipe (xdev, info->in);
1774         dev->out = usb_sndbulkpipe (xdev, info->out);
1775         if (!(info->flags & FLAG_NO_SETINT))
1776             status = usb_set_interface (xdev,
1777                 interface->desc.bInterfaceNumber,
1778                 interface->desc.bAlternateSetting);
1779         else
1780             status = 0;
1781 
1782     }
1783     if (status >= 0 && dev->status)
1784         status = init_status (dev, udev);
1785     if (status < 0)
1786         goto out3;
1787 
1788     if (!dev->rx_urb_size)
1789         dev->rx_urb_size = dev->hard_mtu;
1790     dev->maxpacket = usb_maxpacket(dev->udev, dev->out);
1791     if (dev->maxpacket == 0) {
1792         /* that is a broken device */
1793         status = -ENODEV;
1794         goto out4;
1795     }
1796 
1797     /* let userspace know we have a random address */
1798     if (ether_addr_equal(net->dev_addr, node_id))
1799         net->addr_assign_type = NET_ADDR_RANDOM;
1800 
1801     if ((dev->driver_info->flags & FLAG_WLAN) != 0)
1802         SET_NETDEV_DEVTYPE(net, &wlan_type);
1803     if ((dev->driver_info->flags & FLAG_WWAN) != 0)
1804         SET_NETDEV_DEVTYPE(net, &wwan_type);
1805 
1806     /* initialize max rx_qlen and tx_qlen */
1807     usbnet_update_max_qlen(dev);
1808 
1809     if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&
1810         !(info->flags & FLAG_MULTI_PACKET)) {
1811         dev->padding_pkt = kzalloc(1, GFP_KERNEL);
1812         if (!dev->padding_pkt) {
1813             status = -ENOMEM;
1814             goto out4;
1815         }
1816     }
1817 
1818     status = register_netdev (net);
1819     if (status)
1820         goto out5;
1821     netif_info(dev, probe, dev->net,
1822            "register '%s' at usb-%s-%s, %s, %pM\n",
1823            udev->dev.driver->name,
1824            xdev->bus->bus_name, xdev->devpath,
1825            dev->driver_info->description,
1826            net->dev_addr);
1827 
1828     // ok, it's ready to go.
1829     usb_set_intfdata (udev, dev);
1830 
1831     netif_device_attach (net);
1832 
1833     if (dev->driver_info->flags & FLAG_LINK_INTR)
1834         usbnet_link_change(dev, 0, 0);
1835 
1836     return 0;
1837 
1838 out5:
1839     kfree(dev->padding_pkt);
1840 out4:
1841     usb_free_urb(dev->interrupt);
1842 out3:
1843     if (info->unbind)
1844         info->unbind (dev, udev);
1845 out1:
1846     /* subdrivers must undo all they did in bind() if they
1847      * fail it, but we may fail later and a deferred kevent
1848      * may trigger an error resubmitting itself and, worse,
1849      * schedule a timer. So we kill it all just in case.
1850      */
1851     cancel_work_sync(&dev->kevent);
1852     del_timer_sync(&dev->delay);
1853     free_percpu(net->tstats);
1854 out0:
1855     free_netdev(net);
1856 out:
1857     return status;
1858 }
1859 EXPORT_SYMBOL_GPL(usbnet_probe);
1860 
1861 /*-------------------------------------------------------------------------*/
1862 
1863 /*
1864  * suspend the whole driver as soon as the first interface is suspended
1865  * resume only when the last interface is resumed
1866  */
1867 
1868 int usbnet_suspend (struct usb_interface *intf, pm_message_t message)
1869 {
1870     struct usbnet       *dev = usb_get_intfdata(intf);
1871 
1872     if (!dev->suspend_count++) {
1873         spin_lock_irq(&dev->txq.lock);
1874         /* don't autosuspend while transmitting */
1875         if (dev->txq.qlen && PMSG_IS_AUTO(message)) {
1876             dev->suspend_count--;
1877             spin_unlock_irq(&dev->txq.lock);
1878             return -EBUSY;
1879         } else {
1880             set_bit(EVENT_DEV_ASLEEP, &dev->flags);
1881             spin_unlock_irq(&dev->txq.lock);
1882         }
1883         /*
1884          * accelerate emptying of the rx and queues, to avoid
1885          * having everything error out.
1886          */
1887         netif_device_detach (dev->net);
1888         usbnet_terminate_urbs(dev);
1889         __usbnet_status_stop_force(dev);
1890 
1891         /*
1892          * reattach so runtime management can use and
1893          * wake the device
1894          */
1895         netif_device_attach (dev->net);
1896     }
1897     return 0;
1898 }
1899 EXPORT_SYMBOL_GPL(usbnet_suspend);
1900 
1901 int usbnet_resume (struct usb_interface *intf)
1902 {
1903     struct usbnet       *dev = usb_get_intfdata(intf);
1904     struct sk_buff          *skb;
1905     struct urb              *res;
1906     int                     retval;
1907 
1908     if (!--dev->suspend_count) {
1909         /* resume interrupt URB if it was previously submitted */
1910         __usbnet_status_start_force(dev, GFP_NOIO);
1911 
1912         spin_lock_irq(&dev->txq.lock);
1913         while ((res = usb_get_from_anchor(&dev->deferred))) {
1914 
1915             skb = (struct sk_buff *)res->context;
1916             retval = usb_submit_urb(res, GFP_ATOMIC);
1917             if (retval < 0) {
1918                 dev_kfree_skb_any(skb);
1919                 kfree(res->sg);
1920                 usb_free_urb(res);
1921                 usb_autopm_put_interface_async(dev->intf);
1922             } else {
1923                 netif_trans_update(dev->net);
1924                 __skb_queue_tail(&dev->txq, skb);
1925             }
1926         }
1927 
1928         smp_mb();
1929         clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
1930         spin_unlock_irq(&dev->txq.lock);
1931 
1932         if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
1933             /* handle remote wakeup ASAP
1934              * we cannot race against stop
1935              */
1936             if (netif_device_present(dev->net) &&
1937                 !timer_pending(&dev->delay) &&
1938                 !test_bit(EVENT_RX_HALT, &dev->flags))
1939                     rx_alloc_submit(dev, GFP_NOIO);
1940 
1941             if (!(dev->txq.qlen >= TX_QLEN(dev)))
1942                 netif_tx_wake_all_queues(dev->net);
1943             tasklet_schedule (&dev->bh);
1944         }
1945     }
1946 
1947     if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
1948         usb_autopm_get_interface_no_resume(intf);
1949 
1950     return 0;
1951 }
1952 EXPORT_SYMBOL_GPL(usbnet_resume);
1953 
1954 /*
1955  * Either a subdriver implements manage_power, then it is assumed to always
1956  * be ready to be suspended or it reports the readiness to be suspended
1957  * explicitly
1958  */
1959 void usbnet_device_suggests_idle(struct usbnet *dev)
1960 {
1961     if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
1962         dev->intf->needs_remote_wakeup = 1;
1963         usb_autopm_put_interface_async(dev->intf);
1964     }
1965 }
1966 EXPORT_SYMBOL(usbnet_device_suggests_idle);
1967 
1968 /*
1969  * For devices that can do without special commands
1970  */
1971 int usbnet_manage_power(struct usbnet *dev, int on)
1972 {
1973     dev->intf->needs_remote_wakeup = on;
1974     return 0;
1975 }
1976 EXPORT_SYMBOL(usbnet_manage_power);
1977 
1978 void usbnet_link_change(struct usbnet *dev, bool link, bool need_reset)
1979 {
1980     /* update link after link is reseted */
1981     if (link && !need_reset)
1982         netif_carrier_on(dev->net);
1983     else
1984         netif_carrier_off(dev->net);
1985 
1986     if (need_reset && link)
1987         usbnet_defer_kevent(dev, EVENT_LINK_RESET);
1988     else
1989         usbnet_defer_kevent(dev, EVENT_LINK_CHANGE);
1990 }
1991 EXPORT_SYMBOL(usbnet_link_change);
1992 
1993 /*-------------------------------------------------------------------------*/
1994 static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
1995                  u16 value, u16 index, void *data, u16 size)
1996 {
1997     void *buf = NULL;
1998     int err = -ENOMEM;
1999 
2000     netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
2001            " value=0x%04x index=0x%04x size=%d\n",
2002            cmd, reqtype, value, index, size);
2003 
2004     if (size) {
2005         buf = kmalloc(size, GFP_NOIO);
2006         if (!buf)
2007             goto out;
2008     }
2009 
2010     err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
2011                   cmd, reqtype, value, index, buf, size,
2012                   USB_CTRL_GET_TIMEOUT);
2013     if (err > 0 && err <= size) {
2014         if (data)
2015             memcpy(data, buf, err);
2016         else
2017             netdev_dbg(dev->net,
2018                    "Huh? Data requested but thrown away.\n");
2019     }
2020     kfree(buf);
2021 out:
2022     return err;
2023 }
2024 
2025 static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2026                   u16 value, u16 index, const void *data,
2027                   u16 size)
2028 {
2029     void *buf = NULL;
2030     int err = -ENOMEM;
2031 
2032     netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2033            " value=0x%04x index=0x%04x size=%d\n",
2034            cmd, reqtype, value, index, size);
2035 
2036     if (data) {
2037         buf = kmemdup(data, size, GFP_NOIO);
2038         if (!buf)
2039             goto out;
2040     } else {
2041         if (size) {
2042             WARN_ON_ONCE(1);
2043             err = -EINVAL;
2044             goto out;
2045         }
2046     }
2047 
2048     err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
2049                   cmd, reqtype, value, index, buf, size,
2050                   USB_CTRL_SET_TIMEOUT);
2051     kfree(buf);
2052 
2053 out:
2054     return err;
2055 }
2056 
2057 /*
2058  * The function can't be called inside suspend/resume callback,
2059  * otherwise deadlock will be caused.
2060  */
2061 int usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2062             u16 value, u16 index, void *data, u16 size)
2063 {
2064     int ret;
2065 
2066     if (usb_autopm_get_interface(dev->intf) < 0)
2067         return -ENODEV;
2068     ret = __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2069                 data, size);
2070     usb_autopm_put_interface(dev->intf);
2071     return ret;
2072 }
2073 EXPORT_SYMBOL_GPL(usbnet_read_cmd);
2074 
2075 /*
2076  * The function can't be called inside suspend/resume callback,
2077  * otherwise deadlock will be caused.
2078  */
2079 int usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
2080              u16 value, u16 index, const void *data, u16 size)
2081 {
2082     int ret;
2083 
2084     if (usb_autopm_get_interface(dev->intf) < 0)
2085         return -ENODEV;
2086     ret = __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2087                  data, size);
2088     usb_autopm_put_interface(dev->intf);
2089     return ret;
2090 }
2091 EXPORT_SYMBOL_GPL(usbnet_write_cmd);
2092 
2093 /*
2094  * The function can be called inside suspend/resume callback safely
2095  * and should only be called by suspend/resume callback generally.
2096  */
2097 int usbnet_read_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2098               u16 value, u16 index, void *data, u16 size)
2099 {
2100     return __usbnet_read_cmd(dev, cmd, reqtype, value, index,
2101                  data, size);
2102 }
2103 EXPORT_SYMBOL_GPL(usbnet_read_cmd_nopm);
2104 
2105 /*
2106  * The function can be called inside suspend/resume callback safely
2107  * and should only be called by suspend/resume callback generally.
2108  */
2109 int usbnet_write_cmd_nopm(struct usbnet *dev, u8 cmd, u8 reqtype,
2110               u16 value, u16 index, const void *data,
2111               u16 size)
2112 {
2113     return __usbnet_write_cmd(dev, cmd, reqtype, value, index,
2114                   data, size);
2115 }
2116 EXPORT_SYMBOL_GPL(usbnet_write_cmd_nopm);
2117 
2118 static void usbnet_async_cmd_cb(struct urb *urb)
2119 {
2120     struct usb_ctrlrequest *req = (struct usb_ctrlrequest *)urb->context;
2121     int status = urb->status;
2122 
2123     if (status < 0)
2124         dev_dbg(&urb->dev->dev, "%s failed with %d",
2125             __func__, status);
2126 
2127     kfree(req);
2128     usb_free_urb(urb);
2129 }
2130 
2131 /*
2132  * The caller must make sure that device can't be put into suspend
2133  * state until the control URB completes.
2134  */
2135 int usbnet_write_cmd_async(struct usbnet *dev, u8 cmd, u8 reqtype,
2136                u16 value, u16 index, const void *data, u16 size)
2137 {
2138     struct usb_ctrlrequest *req;
2139     struct urb *urb;
2140     int err = -ENOMEM;
2141     void *buf = NULL;
2142 
2143     netdev_dbg(dev->net, "usbnet_write_cmd cmd=0x%02x reqtype=%02x"
2144            " value=0x%04x index=0x%04x size=%d\n",
2145            cmd, reqtype, value, index, size);
2146 
2147     urb = usb_alloc_urb(0, GFP_ATOMIC);
2148     if (!urb)
2149         goto fail;
2150 
2151     if (data) {
2152         buf = kmemdup(data, size, GFP_ATOMIC);
2153         if (!buf) {
2154             netdev_err(dev->net, "Error allocating buffer"
2155                    " in %s!\n", __func__);
2156             goto fail_free_urb;
2157         }
2158     }
2159 
2160     req = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
2161     if (!req)
2162         goto fail_free_buf;
2163 
2164     req->bRequestType = reqtype;
2165     req->bRequest = cmd;
2166     req->wValue = cpu_to_le16(value);
2167     req->wIndex = cpu_to_le16(index);
2168     req->wLength = cpu_to_le16(size);
2169 
2170     usb_fill_control_urb(urb, dev->udev,
2171                  usb_sndctrlpipe(dev->udev, 0),
2172                  (void *)req, buf, size,
2173                  usbnet_async_cmd_cb, req);
2174     urb->transfer_flags |= URB_FREE_BUFFER;
2175 
2176     err = usb_submit_urb(urb, GFP_ATOMIC);
2177     if (err < 0) {
2178         netdev_err(dev->net, "Error submitting the control"
2179                " message: status=%d\n", err);
2180         goto fail_free_all;
2181     }
2182     return 0;
2183 
2184 fail_free_all:
2185     kfree(req);
2186 fail_free_buf:
2187     kfree(buf);
2188     /*
2189      * avoid a double free
2190      * needed because the flag can be set only
2191      * after filling the URB
2192      */
2193     urb->transfer_flags = 0;
2194 fail_free_urb:
2195     usb_free_urb(urb);
2196 fail:
2197     return err;
2198 
2199 }
2200 EXPORT_SYMBOL_GPL(usbnet_write_cmd_async);
2201 /*-------------------------------------------------------------------------*/
2202 
2203 static int __init usbnet_init(void)
2204 {
2205     /* Compiler should optimize this out. */
2206     BUILD_BUG_ON(
2207         sizeof_field(struct sk_buff, cb) < sizeof(struct skb_data));
2208 
2209     eth_random_addr(node_id);
2210     return 0;
2211 }
2212 module_init(usbnet_init);
2213 
2214 static void __exit usbnet_exit(void)
2215 {
2216 }
2217 module_exit(usbnet_exit);
2218 
2219 MODULE_AUTHOR("David Brownell");
2220 MODULE_DESCRIPTION("USB network driver framework");
2221 MODULE_LICENSE("GPL");
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