u_ether.c 24.3 KB
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/*
 * u_ether.c -- Ethernet-over-USB link layer utilities for Gadget stack
 *
 * Copyright (C) 2003-2005,2008 David Brownell
 * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
 * Copyright (C) 2008 Nokia Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/* #define VERBOSE_DEBUG */

#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <linux/device.h>
#include <linux/ctype.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
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#include <linux/if_vlan.h>
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#include "u_ether.h"


/*
 * This component encapsulates the Ethernet link glue needed to provide
 * one (!) network link through the USB gadget stack, normally "usb0".
 *
 * The control and data models are handled by the function driver which
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 * connects to this code; such as CDC Ethernet (ECM or EEM),
 * "CDC Subset", or RNDIS.  That includes all descriptor and endpoint
 * management.
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 *
 * Link level addressing is handled by this component using module
 * parameters; if no such parameters are provided, random link level
 * addresses are used.  Each end of the link uses one address.  The
 * host end address is exported in various ways, and is often recorded
 * in configuration databases.
 *
 * The driver which assembles each configuration using such a link is
 * responsible for ensuring that each configuration includes at most one
 * instance of is network link.  (The network layer provides ways for
 * this single "physical" link to be used by multiple virtual links.)
 */

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#define UETH__VERSION	"29-May-2008"
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struct eth_dev {
	/* lock is held while accessing port_usb
	 */
	spinlock_t		lock;
	struct gether		*port_usb;

	struct net_device	*net;
	struct usb_gadget	*gadget;

	spinlock_t		req_lock;	/* guard {rx,tx}_reqs */
	struct list_head	tx_reqs, rx_reqs;
	atomic_t		tx_qlen;

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	struct sk_buff_head	rx_frames;

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	unsigned		qmult;

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	unsigned		header_len;
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	struct sk_buff		*(*wrap)(struct gether *, struct sk_buff *skb);
	int			(*unwrap)(struct gether *,
						struct sk_buff *skb,
						struct sk_buff_head *list);
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	struct work_struct	work;

	unsigned long		todo;
#define	WORK_RX_MEMORY		0

	bool			zlp;
	u8			host_mac[ETH_ALEN];
};

/*-------------------------------------------------------------------------*/

#define RX_EXTRA	20	/* bytes guarding against rx overflows */

#define DEFAULT_QLEN	2	/* double buffering by default */

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/* for dual-speed hardware, use deeper queues at high/super speed */
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static inline int qlen(struct usb_gadget *gadget, unsigned qmult)
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{
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	if (gadget_is_dualspeed(gadget) && (gadget->speed == USB_SPEED_HIGH ||
					    gadget->speed == USB_SPEED_SUPER))
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		return qmult * DEFAULT_QLEN;
	else
		return DEFAULT_QLEN;
}

/*-------------------------------------------------------------------------*/

/* REVISIT there must be a better way than having two sets
 * of debug calls ...
 */

#undef DBG
#undef VDBG
#undef ERROR
#undef INFO

#define xprintk(d, level, fmt, args...) \
	printk(level "%s: " fmt , (d)->net->name , ## args)

#ifdef DEBUG
#undef DEBUG
#define DBG(dev, fmt, args...) \
	xprintk(dev , KERN_DEBUG , fmt , ## args)
#else
#define DBG(dev, fmt, args...) \
	do { } while (0)
#endif /* DEBUG */

#ifdef VERBOSE_DEBUG
#define VDBG	DBG
#else
#define VDBG(dev, fmt, args...) \
	do { } while (0)
#endif /* DEBUG */

#define ERROR(dev, fmt, args...) \
	xprintk(dev , KERN_ERR , fmt , ## args)
#define INFO(dev, fmt, args...) \
	xprintk(dev , KERN_INFO , fmt , ## args)

/*-------------------------------------------------------------------------*/

/* NETWORK DRIVER HOOKUP (to the layer above this driver) */

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static int ueth_change_mtu(struct net_device *net, int new_mtu)
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{
	struct eth_dev	*dev = netdev_priv(net);
	unsigned long	flags;
	int		status = 0;

	/* don't change MTU on "live" link (peer won't know) */
	spin_lock_irqsave(&dev->lock, flags);
	if (dev->port_usb)
		status = -EBUSY;
	else if (new_mtu <= ETH_HLEN || new_mtu > ETH_FRAME_LEN)
		status = -ERANGE;
	else
		net->mtu = new_mtu;
	spin_unlock_irqrestore(&dev->lock, flags);

	return status;
}

static void eth_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *p)
{
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	struct eth_dev *dev = netdev_priv(net);
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	strlcpy(p->driver, "g_ether", sizeof(p->driver));
	strlcpy(p->version, UETH__VERSION, sizeof(p->version));
	strlcpy(p->fw_version, dev->gadget->name, sizeof(p->fw_version));
	strlcpy(p->bus_info, dev_name(&dev->gadget->dev), sizeof(p->bus_info));
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}

/* REVISIT can also support:
 *   - WOL (by tracking suspends and issuing remote wakeup)
 *   - msglevel (implies updated messaging)
 *   - ... probably more ethtool ops
 */

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static const struct ethtool_ops ops = {
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	.get_drvinfo = eth_get_drvinfo,
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	.get_link = ethtool_op_get_link,
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};

static void defer_kevent(struct eth_dev *dev, int flag)
{
	if (test_and_set_bit(flag, &dev->todo))
		return;
	if (!schedule_work(&dev->work))
		ERROR(dev, "kevent %d may have been dropped\n", flag);
	else
		DBG(dev, "kevent %d scheduled\n", flag);
}

static void rx_complete(struct usb_ep *ep, struct usb_request *req);

static int
rx_submit(struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
{
	struct sk_buff	*skb;
	int		retval = -ENOMEM;
	size_t		size = 0;
	struct usb_ep	*out;
	unsigned long	flags;

	spin_lock_irqsave(&dev->lock, flags);
	if (dev->port_usb)
		out = dev->port_usb->out_ep;
	else
		out = NULL;
	spin_unlock_irqrestore(&dev->lock, flags);

	if (!out)
		return -ENOTCONN;


	/* Padding up to RX_EXTRA handles minor disagreements with host.
	 * Normally we use the USB "terminate on short read" convention;
	 * so allow up to (N*maxpacket), since that memory is normally
	 * already allocated.  Some hardware doesn't deal well with short
	 * reads (e.g. DMA must be N*maxpacket), so for now don't trim a
	 * byte off the end (to force hardware errors on overflow).
	 *
	 * RNDIS uses internal framing, and explicitly allows senders to
	 * pad to end-of-packet.  That's potentially nice for speed, but
	 * means receivers can't recover lost synch on their own (because
	 * new packets don't only start after a short RX).
	 */
	size += sizeof(struct ethhdr) + dev->net->mtu + RX_EXTRA;
	size += dev->port_usb->header_len;
	size += out->maxpacket - 1;
	size -= size % out->maxpacket;

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	if (dev->port_usb->is_fixed)
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		size = max_t(size_t, size, dev->port_usb->fixed_out_len);
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	skb = alloc_skb(size + NET_IP_ALIGN, gfp_flags);
	if (skb == NULL) {
		DBG(dev, "no rx skb\n");
		goto enomem;
	}

	/* Some platforms perform better when IP packets are aligned,
	 * but on at least one, checksumming fails otherwise.  Note:
	 * RNDIS headers involve variable numbers of LE32 values.
	 */
	skb_reserve(skb, NET_IP_ALIGN);

	req->buf = skb->data;
	req->length = size;
	req->complete = rx_complete;
	req->context = skb;

	retval = usb_ep_queue(out, req, gfp_flags);
	if (retval == -ENOMEM)
enomem:
		defer_kevent(dev, WORK_RX_MEMORY);
	if (retval) {
		DBG(dev, "rx submit --> %d\n", retval);
		if (skb)
			dev_kfree_skb_any(skb);
		spin_lock_irqsave(&dev->req_lock, flags);
		list_add(&req->list, &dev->rx_reqs);
		spin_unlock_irqrestore(&dev->req_lock, flags);
	}
	return retval;
}

static void rx_complete(struct usb_ep *ep, struct usb_request *req)
{
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	struct sk_buff	*skb = req->context, *skb2;
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	struct eth_dev	*dev = ep->driver_data;
	int		status = req->status;

	switch (status) {

	/* normal completion */
	case 0:
		skb_put(skb, req->actual);

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		if (dev->unwrap) {
			unsigned long	flags;
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			spin_lock_irqsave(&dev->lock, flags);
			if (dev->port_usb) {
				status = dev->unwrap(dev->port_usb,
							skb,
							&dev->rx_frames);
			} else {
				dev_kfree_skb_any(skb);
				status = -ENOTCONN;
			}
			spin_unlock_irqrestore(&dev->lock, flags);
		} else {
			skb_queue_tail(&dev->rx_frames, skb);
		}
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		skb = NULL;
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		skb2 = skb_dequeue(&dev->rx_frames);
		while (skb2) {
			if (status < 0
					|| ETH_HLEN > skb2->len
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					|| skb2->len > VLAN_ETH_FRAME_LEN) {
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				dev->net->stats.rx_errors++;
				dev->net->stats.rx_length_errors++;
				DBG(dev, "rx length %d\n", skb2->len);
				dev_kfree_skb_any(skb2);
				goto next_frame;
			}
			skb2->protocol = eth_type_trans(skb2, dev->net);
			dev->net->stats.rx_packets++;
			dev->net->stats.rx_bytes += skb2->len;

			/* no buffer copies needed, unless hardware can't
			 * use skb buffers.
			 */
			status = netif_rx(skb2);
next_frame:
			skb2 = skb_dequeue(&dev->rx_frames);
		}
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		break;

	/* software-driven interface shutdown */
	case -ECONNRESET:		/* unlink */
	case -ESHUTDOWN:		/* disconnect etc */
		VDBG(dev, "rx shutdown, code %d\n", status);
		goto quiesce;

	/* for hardware automagic (such as pxa) */
	case -ECONNABORTED:		/* endpoint reset */
		DBG(dev, "rx %s reset\n", ep->name);
		defer_kevent(dev, WORK_RX_MEMORY);
quiesce:
		dev_kfree_skb_any(skb);
		goto clean;

	/* data overrun */
	case -EOVERFLOW:
		dev->net->stats.rx_over_errors++;
		/* FALLTHROUGH */

	default:
		dev->net->stats.rx_errors++;
		DBG(dev, "rx status %d\n", status);
		break;
	}

	if (skb)
		dev_kfree_skb_any(skb);
	if (!netif_running(dev->net)) {
clean:
		spin_lock(&dev->req_lock);
		list_add(&req->list, &dev->rx_reqs);
		spin_unlock(&dev->req_lock);
		req = NULL;
	}
	if (req)
		rx_submit(dev, req, GFP_ATOMIC);
}

static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
{
	unsigned		i;
	struct usb_request	*req;

	if (!n)
		return -ENOMEM;

	/* queue/recycle up to N requests */
	i = n;
	list_for_each_entry(req, list, list) {
		if (i-- == 0)
			goto extra;
	}
	while (i--) {
		req = usb_ep_alloc_request(ep, GFP_ATOMIC);
		if (!req)
			return list_empty(list) ? -ENOMEM : 0;
		list_add(&req->list, list);
	}
	return 0;

extra:
	/* free extras */
	for (;;) {
		struct list_head	*next;

		next = req->list.next;
		list_del(&req->list);
		usb_ep_free_request(ep, req);

		if (next == list)
			break;

		req = container_of(next, struct usb_request, list);
	}
	return 0;
}

static int alloc_requests(struct eth_dev *dev, struct gether *link, unsigned n)
{
	int	status;

	spin_lock(&dev->req_lock);
	status = prealloc(&dev->tx_reqs, link->in_ep, n);
	if (status < 0)
		goto fail;
	status = prealloc(&dev->rx_reqs, link->out_ep, n);
	if (status < 0)
		goto fail;
	goto done;
fail:
	DBG(dev, "can't alloc requests\n");
done:
	spin_unlock(&dev->req_lock);
	return status;
}

static void rx_fill(struct eth_dev *dev, gfp_t gfp_flags)
{
	struct usb_request	*req;
	unsigned long		flags;

	/* fill unused rxq slots with some skb */
	spin_lock_irqsave(&dev->req_lock, flags);
	while (!list_empty(&dev->rx_reqs)) {
		req = container_of(dev->rx_reqs.next,
				struct usb_request, list);
		list_del_init(&req->list);
		spin_unlock_irqrestore(&dev->req_lock, flags);

		if (rx_submit(dev, req, gfp_flags) < 0) {
			defer_kevent(dev, WORK_RX_MEMORY);
			return;
		}

		spin_lock_irqsave(&dev->req_lock, flags);
	}
	spin_unlock_irqrestore(&dev->req_lock, flags);
}

static void eth_work(struct work_struct *work)
{
	struct eth_dev	*dev = container_of(work, struct eth_dev, work);

	if (test_and_clear_bit(WORK_RX_MEMORY, &dev->todo)) {
		if (netif_running(dev->net))
			rx_fill(dev, GFP_KERNEL);
	}

	if (dev->todo)
		DBG(dev, "work done, flags = 0x%lx\n", dev->todo);
}

static void tx_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct sk_buff	*skb = req->context;
	struct eth_dev	*dev = ep->driver_data;

	switch (req->status) {
	default:
		dev->net->stats.tx_errors++;
		VDBG(dev, "tx err %d\n", req->status);
		/* FALLTHROUGH */
	case -ECONNRESET:		/* unlink */
	case -ESHUTDOWN:		/* disconnect etc */
		break;
	case 0:
		dev->net->stats.tx_bytes += skb->len;
	}
	dev->net->stats.tx_packets++;

	spin_lock(&dev->req_lock);
	list_add(&req->list, &dev->tx_reqs);
	spin_unlock(&dev->req_lock);
	dev_kfree_skb_any(skb);

	atomic_dec(&dev->tx_qlen);
	if (netif_carrier_ok(dev->net))
		netif_wake_queue(dev->net);
}

static inline int is_promisc(u16 cdc_filter)
{
	return cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
}

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static netdev_tx_t eth_start_xmit(struct sk_buff *skb,
					struct net_device *net)
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{
	struct eth_dev		*dev = netdev_priv(net);
	int			length = skb->len;
	int			retval;
	struct usb_request	*req = NULL;
	unsigned long		flags;
	struct usb_ep		*in;
	u16			cdc_filter;

	spin_lock_irqsave(&dev->lock, flags);
	if (dev->port_usb) {
		in = dev->port_usb->in_ep;
		cdc_filter = dev->port_usb->cdc_filter;
	} else {
		in = NULL;
		cdc_filter = 0;
	}
	spin_unlock_irqrestore(&dev->lock, flags);

	if (!in) {
		dev_kfree_skb_any(skb);
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		return NETDEV_TX_OK;
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	}

	/* apply outgoing CDC or RNDIS filters */
	if (!is_promisc(cdc_filter)) {
		u8		*dest = skb->data;

		if (is_multicast_ether_addr(dest)) {
			u16	type;

			/* ignores USB_CDC_PACKET_TYPE_MULTICAST and host
			 * SET_ETHERNET_MULTICAST_FILTERS requests
			 */
			if (is_broadcast_ether_addr(dest))
				type = USB_CDC_PACKET_TYPE_BROADCAST;
			else
				type = USB_CDC_PACKET_TYPE_ALL_MULTICAST;
			if (!(cdc_filter & type)) {
				dev_kfree_skb_any(skb);
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				return NETDEV_TX_OK;
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			}
		}
		/* ignores USB_CDC_PACKET_TYPE_DIRECTED */
	}

	spin_lock_irqsave(&dev->req_lock, flags);
	/*
	 * this freelist can be empty if an interrupt triggered disconnect()
	 * and reconfigured the gadget (shutting down this queue) after the
	 * network stack decided to xmit but before we got the spinlock.
	 */
	if (list_empty(&dev->tx_reqs)) {
		spin_unlock_irqrestore(&dev->req_lock, flags);
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		return NETDEV_TX_BUSY;
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	}

	req = container_of(dev->tx_reqs.next, struct usb_request, list);
	list_del(&req->list);

	/* temporarily stop TX queue when the freelist empties */
	if (list_empty(&dev->tx_reqs))
		netif_stop_queue(net);
	spin_unlock_irqrestore(&dev->req_lock, flags);

	/* no buffer copies needed, unless the network stack did it
	 * or the hardware can't use skb buffers.
	 * or there's not enough space for extra headers we need
	 */
	if (dev->wrap) {
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		unsigned long	flags;
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		spin_lock_irqsave(&dev->lock, flags);
		if (dev->port_usb)
			skb = dev->wrap(dev->port_usb, skb);
		spin_unlock_irqrestore(&dev->lock, flags);
		if (!skb)
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			goto drop;

		length = skb->len;
	}
	req->buf = skb->data;
	req->context = skb;
	req->complete = tx_complete;

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	/* NCM requires no zlp if transfer is dwNtbInMaxSize */
	if (dev->port_usb->is_fixed &&
	    length == dev->port_usb->fixed_in_len &&
	    (length % in->maxpacket) == 0)
		req->zero = 0;
	else
		req->zero = 1;

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	/* use zlp framing on tx for strict CDC-Ether conformance,
	 * though any robust network rx path ignores extra padding.
	 * and some hardware doesn't like to write zlps.
	 */
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	if (req->zero && !dev->zlp && (length % in->maxpacket) == 0)
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		length++;

	req->length = length;

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	/* throttle high/super speed IRQ rate back slightly */
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	if (gadget_is_dualspeed(dev->gadget))
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		req->no_interrupt = (dev->gadget->speed == USB_SPEED_HIGH ||
				     dev->gadget->speed == USB_SPEED_SUPER)
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			? ((atomic_read(&dev->tx_qlen) % dev->qmult) != 0)
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			: 0;

	retval = usb_ep_queue(in, req, GFP_ATOMIC);
	switch (retval) {
	default:
		DBG(dev, "tx queue err %d\n", retval);
		break;
	case 0:
		net->trans_start = jiffies;
		atomic_inc(&dev->tx_qlen);
	}

	if (retval) {
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		dev_kfree_skb_any(skb);
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drop:
		dev->net->stats.tx_dropped++;
		spin_lock_irqsave(&dev->req_lock, flags);
		if (list_empty(&dev->tx_reqs))
			netif_start_queue(net);
		list_add(&req->list, &dev->tx_reqs);
		spin_unlock_irqrestore(&dev->req_lock, flags);
	}
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	return NETDEV_TX_OK;
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}

/*-------------------------------------------------------------------------*/

static void eth_start(struct eth_dev *dev, gfp_t gfp_flags)
{
	DBG(dev, "%s\n", __func__);

	/* fill the rx queue */
	rx_fill(dev, gfp_flags);

	/* and open the tx floodgates */
	atomic_set(&dev->tx_qlen, 0);
	netif_wake_queue(dev->net);
}

static int eth_open(struct net_device *net)
{
	struct eth_dev	*dev = netdev_priv(net);
	struct gether	*link;

	DBG(dev, "%s\n", __func__);
	if (netif_carrier_ok(dev->net))
		eth_start(dev, GFP_KERNEL);

	spin_lock_irq(&dev->lock);
	link = dev->port_usb;
	if (link && link->open)
		link->open(link);
	spin_unlock_irq(&dev->lock);

	return 0;
}

static int eth_stop(struct net_device *net)
{
	struct eth_dev	*dev = netdev_priv(net);
	unsigned long	flags;

	VDBG(dev, "%s\n", __func__);
	netif_stop_queue(net);

	DBG(dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
		dev->net->stats.rx_packets, dev->net->stats.tx_packets,
		dev->net->stats.rx_errors, dev->net->stats.tx_errors
		);

	/* ensure there are no more active requests */
	spin_lock_irqsave(&dev->lock, flags);
	if (dev->port_usb) {
		struct gether	*link = dev->port_usb;
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		const struct usb_endpoint_descriptor *in;
		const struct usb_endpoint_descriptor *out;
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		if (link->close)
			link->close(link);

		/* NOTE:  we have no abort-queue primitive we could use
		 * to cancel all pending I/O.  Instead, we disable then
		 * reenable the endpoints ... this idiom may leave toggle
		 * wrong, but that's a self-correcting error.
		 *
		 * REVISIT:  we *COULD* just let the transfers complete at
		 * their own pace; the network stack can handle old packets.
		 * For the moment we leave this here, since it works.
		 */
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		in = link->in_ep->desc;
		out = link->out_ep->desc;
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		usb_ep_disable(link->in_ep);
		usb_ep_disable(link->out_ep);
		if (netif_carrier_ok(net)) {
			DBG(dev, "host still using in/out endpoints\n");
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			link->in_ep->desc = in;
			link->out_ep->desc = out;
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			usb_ep_enable(link->in_ep);
			usb_ep_enable(link->out_ep);
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		}
	}
	spin_unlock_irqrestore(&dev->lock, flags);

	return 0;
}

/*-------------------------------------------------------------------------*/

698
static int get_ether_addr(const char *str, u8 *dev_addr)
699 700 701 702 703 704 705 706 707
{
	if (str) {
		unsigned	i;

		for (i = 0; i < 6; i++) {
			unsigned char num;

			if ((*str == '.') || (*str == ':'))
				str++;
708 709
			num = hex_to_bin(*str++) << 4;
			num |= hex_to_bin(*str++);
710 711 712 713 714
			dev_addr [i] = num;
		}
		if (is_valid_ether_addr(dev_addr))
			return 0;
	}
J
Joe Perches 已提交
715
	eth_random_addr(dev_addr);
716 717 718
	return 1;
}

719 720 721 722 723 724 725 726
static const struct net_device_ops eth_netdev_ops = {
	.ndo_open		= eth_open,
	.ndo_stop		= eth_stop,
	.ndo_start_xmit		= eth_start_xmit,
	.ndo_change_mtu		= ueth_change_mtu,
	.ndo_set_mac_address 	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
};
727

728 729 730 731
static struct device_type gadget_type = {
	.name	= "gadget",
};

732
/**
733
 * gether_setup_name - initialize one ethernet-over-usb link
734 735 736
 * @g: gadget to associated with these links
 * @ethaddr: NULL, or a buffer in which the ethernet address of the
 *	host side of the link is recorded
737
 * @netname: name for network device (for example, "usb")
738 739 740 741 742 743 744 745
 * Context: may sleep
 *
 * This sets up the single network link that may be exported by a
 * gadget driver using this framework.  The link layer addresses are
 * set up using module parameters.
 *
 * Returns negative errno, or zero on success
 */
746 747 748
struct eth_dev *gether_setup_name(struct usb_gadget *g,
		const char *dev_addr, const char *host_addr,
		u8 ethaddr[ETH_ALEN], unsigned qmult, const char *netname)
749 750 751 752 753 754 755
{
	struct eth_dev		*dev;
	struct net_device	*net;
	int			status;

	net = alloc_etherdev(sizeof *dev);
	if (!net)
756
		return ERR_PTR(-ENOMEM);
757 758 759 760 761 762 763 764

	dev = netdev_priv(net);
	spin_lock_init(&dev->lock);
	spin_lock_init(&dev->req_lock);
	INIT_WORK(&dev->work, eth_work);
	INIT_LIST_HEAD(&dev->tx_reqs);
	INIT_LIST_HEAD(&dev->rx_reqs);

765 766
	skb_queue_head_init(&dev->rx_frames);

767 768
	/* network device setup */
	dev->net = net;
769
	dev->qmult = qmult;
770
	snprintf(net->name, sizeof(net->name), "%s%%d", netname);
771 772 773 774 775 776 777 778 779 780 781

	if (get_ether_addr(dev_addr, net->dev_addr))
		dev_warn(&g->dev,
			"using random %s ethernet address\n", "self");
	if (get_ether_addr(host_addr, dev->host_mac))
		dev_warn(&g->dev,
			"using random %s ethernet address\n", "host");

	if (ethaddr)
		memcpy(ethaddr, dev->host_mac, ETH_ALEN);

782 783
	net->netdev_ops = &eth_netdev_ops;

784 785 786 787
	SET_ETHTOOL_OPS(net, &ops);

	dev->gadget = g;
	SET_NETDEV_DEV(net, &g->dev);
788
	SET_NETDEV_DEVTYPE(net, &gadget_type);
789 790 791 792 793

	status = register_netdev(net);
	if (status < 0) {
		dev_dbg(&g->dev, "register_netdev failed, %d\n", status);
		free_netdev(net);
794
		dev = ERR_PTR(status);
795
	} else {
796 797
		INFO(dev, "MAC %pM\n", net->dev_addr);
		INFO(dev, "HOST MAC %pM\n", dev->host_mac);
798

799 800 801 802 803
		/* two kinds of host-initiated state changes:
		 *  - iff DATA transfer is active, carrier is "on"
		 *  - tx queueing enabled if open *and* carrier is "on"
		 */
		netif_carrier_off(net);
804 805
	}

806
	return dev;
807
}
808
EXPORT_SYMBOL(gether_setup_name);
809 810 811 812 813 814 815

/**
 * gether_cleanup - remove Ethernet-over-USB device
 * Context: may sleep
 *
 * This is called to free all resources allocated by @gether_setup().
 */
816
void gether_cleanup(struct eth_dev *dev)
817
{
818
	if (!dev)
819 820
		return;

821 822 823
	unregister_netdev(dev->net);
	flush_work(&dev->work);
	free_netdev(dev->net);
824
}
825
EXPORT_SYMBOL(gether_cleanup);
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844

/**
 * gether_connect - notify network layer that USB link is active
 * @link: the USB link, set up with endpoints, descriptors matching
 *	current device speed, and any framing wrapper(s) set up.
 * Context: irqs blocked
 *
 * This is called to activate endpoints and let the network layer know
 * the connection is active ("carrier detect").  It may cause the I/O
 * queues to open and start letting network packets flow, but will in
 * any case activate the endpoints so that they respond properly to the
 * USB host.
 *
 * Verify net_device pointer returned using IS_ERR().  If it doesn't
 * indicate some error code (negative errno), ep->driver_data values
 * have been overwritten.
 */
struct net_device *gether_connect(struct gether *link)
{
845
	struct eth_dev		*dev = link->ioport;
846 847 848 849 850 851
	int			result = 0;

	if (!dev)
		return ERR_PTR(-EINVAL);

	link->in_ep->driver_data = dev;
852
	result = usb_ep_enable(link->in_ep);
853 854 855 856 857 858 859
	if (result != 0) {
		DBG(dev, "enable %s --> %d\n",
			link->in_ep->name, result);
		goto fail0;
	}

	link->out_ep->driver_data = dev;
860
	result = usb_ep_enable(link->out_ep);
861 862 863 864 865 866 867
	if (result != 0) {
		DBG(dev, "enable %s --> %d\n",
			link->out_ep->name, result);
		goto fail1;
	}

	if (result == 0)
868 869
		result = alloc_requests(dev, link, qlen(dev->gadget,
					dev->qmult));
870 871 872

	if (result == 0) {
		dev->zlp = link->is_zlp_ok;
873
		DBG(dev, "qlen %d\n", qlen(dev->gadget, dev->qmult));
874 875 876 877 878 879 880

		dev->header_len = link->header_len;
		dev->unwrap = link->unwrap;
		dev->wrap = link->wrap;

		spin_lock(&dev->lock);
		dev->port_usb = link;
881 882 883 884 885 886 887
		if (netif_running(dev->net)) {
			if (link->open)
				link->open(link);
		} else {
			if (link->close)
				link->close(link);
		}
888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
		spin_unlock(&dev->lock);

		netif_carrier_on(dev->net);
		if (netif_running(dev->net))
			eth_start(dev, GFP_ATOMIC);

	/* on error, disable any endpoints  */
	} else {
		(void) usb_ep_disable(link->out_ep);
fail1:
		(void) usb_ep_disable(link->in_ep);
	}
fail0:
	/* caller is responsible for cleanup on error */
	if (result < 0)
		return ERR_PTR(result);
	return dev->net;
}
906
EXPORT_SYMBOL(gether_connect);
907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950

/**
 * gether_disconnect - notify network layer that USB link is inactive
 * @link: the USB link, on which gether_connect() was called
 * Context: irqs blocked
 *
 * This is called to deactivate endpoints and let the network layer know
 * the connection went inactive ("no carrier").
 *
 * On return, the state is as if gether_connect() had never been called.
 * The endpoints are inactive, and accordingly without active USB I/O.
 * Pointers to endpoint descriptors and endpoint private data are nulled.
 */
void gether_disconnect(struct gether *link)
{
	struct eth_dev		*dev = link->ioport;
	struct usb_request	*req;

	WARN_ON(!dev);
	if (!dev)
		return;

	DBG(dev, "%s\n", __func__);

	netif_stop_queue(dev->net);
	netif_carrier_off(dev->net);

	/* disable endpoints, forcing (synchronous) completion
	 * of all pending i/o.  then free the request objects
	 * and forget about the endpoints.
	 */
	usb_ep_disable(link->in_ep);
	spin_lock(&dev->req_lock);
	while (!list_empty(&dev->tx_reqs)) {
		req = container_of(dev->tx_reqs.next,
					struct usb_request, list);
		list_del(&req->list);

		spin_unlock(&dev->req_lock);
		usb_ep_free_request(link->in_ep, req);
		spin_lock(&dev->req_lock);
	}
	spin_unlock(&dev->req_lock);
	link->in_ep->driver_data = NULL;
951
	link->in_ep->desc = NULL;
952 953 954 955 956 957 958 959 960 961 962 963 964 965

	usb_ep_disable(link->out_ep);
	spin_lock(&dev->req_lock);
	while (!list_empty(&dev->rx_reqs)) {
		req = container_of(dev->rx_reqs.next,
					struct usb_request, list);
		list_del(&req->list);

		spin_unlock(&dev->req_lock);
		usb_ep_free_request(link->out_ep, req);
		spin_lock(&dev->req_lock);
	}
	spin_unlock(&dev->req_lock);
	link->out_ep->driver_data = NULL;
966
	link->out_ep->desc = NULL;
967 968 969 970 971 972 973 974 975 976

	/* finish forgetting about this USB link episode */
	dev->header_len = 0;
	dev->unwrap = NULL;
	dev->wrap = NULL;

	spin_lock(&dev->lock);
	dev->port_usb = NULL;
	spin_unlock(&dev->lock);
}
977 978 979 980
EXPORT_SYMBOL(gether_disconnect);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");
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