usbnet.c

omap3 linux 2.6 用nocc去除了冗余代码

/*
 * USB Network driver infrastructure
 * Copyright (C) 2000-2005 by David Brownell
 * Copyright (C) 2003-2005 David Hollis <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 * This is a generic "USB networking" framework that works with several
 * kinds of full and high speed networking devices:  host-to-host cables,
 * smart usb peripherals, and actual Ethernet adapters.
 *
 * These devices usually differ in terms of control protocols (if they
 * even have one!) and sometimes they define new framing to wrap or batch
 * Ethernet packets.  Otherwise, they talk to USB pretty much the same,
 * so interface (un)binding, endpoint I/O queues, fault handling, and other
 * issues can usefully be addressed by this framework.
 */

// #define	DEBUG			// error path messages, extra info
// #define	VERBOSE			// more; success messages

#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/workqueue.h>
#include <linux/mii.h>
#include <linux/usb.h>

#include "usbnet.h"

#define DRIVER_VERSION		"22-Aug-2005"


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

/*
 * Nineteen USB 1.1 max size bulk transactions per frame (ms), max.
 * Several dozen bytes of IPv4 data can fit in two such transactions.
 * One maximum size Ethernet packet takes twenty four of them.
 * For high speed, each frame comfortably fits almost 36 max size
 * Ethernet packets (so queues should be bigger).
 *
 * REVISIT qlens should be members of 'struct usbnet'; the goal is to
 * let the USB host controller be busy for 5msec or more before an irq
 * is required, under load.  Jumbograms change the equation.
 */
#define RX_MAX_QUEUE_MEMORY (60 * 1518)
#define	RX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
			(RX_MAX_QUEUE_MEMORY/(dev)->rx_urb_size) : 4)
#define	TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? \
			(RX_MAX_QUEUE_MEMORY/(dev)->hard_mtu) : 4)

// reawaken network queue this soon after stopping; else watchdog barks
#define TX_TIMEOUT_JIFFIES	(5*HZ)

// throttle rx/tx briefly after some faults, so khubd might disconnect()
// us (it polls at HZ/4 usually) before we report too many false errors.
#define THROTTLE_JIFFIES	(HZ/8)

// between wakeups
#define UNLINK_TIMEOUT_MS	3

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

// randomly generated ethernet address
static u8	node_id [ETH_ALEN];

static const char driver_name [] = "usbnet";

/* use ethtool to change the level for any given device */
static int msg_level = -1;
module_param (msg_level, int, 0);
MODULE_PARM_DESC (msg_level, "Override default message level");

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

/* handles CDC Ethernet and many other network "bulk data" interfaces */
int usbnet_get_endpoints(struct usbnet *dev, struct usb_interface *intf)
{
	int				tmp;
	struct usb_host_interface	*alt = NULL;
	struct usb_host_endpoint	*in = NULL, *out = NULL;
	struct usb_host_endpoint	*status = NULL;

	for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
		unsigned	ep;

		in = out = status = NULL;
		alt = intf->altsetting + tmp;

		/* take the first altsetting with in-bulk + out-bulk;
		 * remember any status endpoint, just in case;
		 * ignore other endpoints and altsetttings.
		 */
		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
			struct usb_host_endpoint	*e;
			int				intr = 0;

			e = alt->endpoint + ep;
			switch (e->desc.bmAttributes) {
			case USB_ENDPOINT_XFER_INT:
				if (!usb_endpoint_dir_in(&e->desc))
					continue;
				intr = 1;
				/* FALLTHROUGH */
			case USB_ENDPOINT_XFER_BULK:
				break;
			default:
				continue;
			}
			if (usb_endpoint_dir_in(&e->desc)) {
				if (!intr && !in)
					in = e;
				else if (intr && !status)
					status = e;
			} else {
				if (!out)
					out = e;
			}
		}
		if (in && out)
			break;
	}
	if (!alt || !in || !out)
		return -EINVAL;

	if (alt->desc.bAlternateSetting != 0
			|| !(dev->driver_info->flags & FLAG_NO_SETINT)) {
		tmp = usb_set_interface (dev->udev, alt->desc.bInterfaceNumber,
				alt->desc.bAlternateSetting);
		if (tmp < 0)
			return tmp;
	}

	dev->in = usb_rcvbulkpipe (dev->udev,
			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->out = usb_sndbulkpipe (dev->udev,
			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	dev->status = status;
	return 0;
}
EXPORT_SYMBOL_GPL(usbnet_get_endpoints);

static void intr_complete (struct urb *urb);

static int init_status (struct usbnet *dev, struct usb_interface *intf)
{
	char		*buf = NULL;
	unsigned	pipe = 0;
	unsigned	maxp;
	unsigned	period;

	if (!dev->driver_info->status)
		return 0;

	pipe = usb_rcvintpipe (dev->udev,
			dev->status->desc.bEndpointAddress
				& USB_ENDPOINT_NUMBER_MASK);
	maxp = usb_maxpacket (dev->udev, pipe, 0);

	/* avoid 1 msec chatter:  min 8 msec poll rate */
	period = max ((int) dev->status->desc.bInterval,
		(dev->udev->speed == USB_SPEED_HIGH) ? 7 : 3);

	buf = kmalloc (maxp, GFP_KERNEL);
	if (buf) {
		dev->interrupt = usb_alloc_urb (0, GFP_KERNEL);
		if (!dev->interrupt) {
			kfree (buf);
			return -ENOMEM;
		} else {
			usb_fill_int_urb(dev->interrupt, dev->udev, pipe,
				buf, maxp, intr_complete, dev, period);
			dev_dbg(&intf->dev,
				"status ep%din, %d bytes period %d\n",
				usb_pipeendpoint(pipe), maxp, period);
		}
	}
	return  0;
}

/* Passes this packet up the stack, updating its accounting.
 * Some link protocols batch packets, so their rx_fixup paths
 * can return clones as well as just modify the original skb.
 */
void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
{
	int	status;

	skb->protocol = eth_type_trans (skb, dev->net);
	dev->stats.rx_packets++;
	dev->stats.rx_bytes += skb->len;

	if (netif_msg_rx_status (dev))
		devdbg (dev, "< rx, len %zu, type 0x%x",
			skb->len + sizeof (struct ethhdr), skb->protocol);
	memset (skb->cb, 0, sizeof (struct skb_data));
	status = netif_rx (skb);
	if (status != NET_RX_SUCCESS && netif_msg_rx_err (dev))
		devdbg (dev, "netif_rx status %d", status);
}
EXPORT_SYMBOL_GPL(usbnet_skb_return);


/*-------------------------------------------------------------------------
 *
 * Network Device Driver (peer link to "Host Device", from USB host)
 *
 *-------------------------------------------------------------------------*/

static int usbnet_change_mtu (struct net_device *net, int new_mtu)
{
	struct usbnet	*dev = netdev_priv(net);
	int		ll_mtu = new_mtu + net->hard_header_len;
	int		old_hard_mtu = dev->hard_mtu;
	int		old_rx_urb_size = dev->rx_urb_size;

	if (new_mtu <= 0)
		return -EINVAL;
	// no second zero-length packet read wanted after mtu-sized packets
	if ((ll_mtu % dev->maxpacket) == 0)
		return -EDOM;
	net->mtu = new_mtu;

	dev->hard_mtu = net->mtu + net->hard_header_len;
	if (dev->rx_urb_size == old_hard_mtu) {
		dev->rx_urb_size = dev->hard_mtu;
		if (dev->rx_urb_size > old_rx_urb_size)
			usbnet_unlink_rx_urbs(dev);
	}

	return 0;
}

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

static struct net_device_stats *usbnet_get_stats (struct net_device *net)
{
	struct usbnet	*dev = netdev_priv(net);
	return &dev->stats;
}

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

/* some LK 2.4 HCDs oopsed if we freed or resubmitted urbs from
 * completion callbacks.  2.5 should have fixed those bugs...
 */

static void defer_bh(struct usbnet *dev, struct sk_buff *skb, struct sk_buff_head *list)
{
	unsigned long		flags;

	spin_lock_irqsave(&list->lock, flags);
	__skb_unlink(skb, list);
	spin_unlock(&list->lock);
	spin_lock(&dev->done.lock);
	__skb_queue_tail(&dev->done, skb);
	if (dev->done.qlen == 1)
		tasklet_schedule(&dev->bh);
	spin_unlock_irqrestore(&dev->done.lock, flags);
}

/* some work can't be done in tasklets, so we use keventd
 *
 * NOTE:  annoying asymmetry:  if it's active, schedule_work() fails,
 * but tasklet_schedule() doesn't.  hope the failure is rare.
 */
void usbnet_defer_kevent (struct usbnet *dev, int work)
{
	set_bit (work, &dev->flags);
	if (!schedule_work (&dev->kevent))
		deverr (dev, "kevent %d may have been dropped", work);
	else
		devdbg (dev, "kevent %d scheduled", work);
}
EXPORT_SYMBOL_GPL(usbnet_defer_kevent);

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

static void rx_complete (struct urb *urb);

static void rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
{
	struct sk_buff		*skb;
	struct skb_data		*entry;
	int			retval = 0;
	unsigned long		lockflags;
	size_t			size = dev->rx_urb_size;

	if ((skb = alloc_skb (size + NET_IP_ALIGN, flags)) == NULL) {
		if (netif_msg_rx_err (dev))
			devdbg (dev, "no rx skb");
		usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
		usb_free_urb (urb);
		return;
	}
	skb_reserve (skb, NET_IP_ALIGN);

	entry = (struct skb_data *) skb->cb;
	entry->urb = urb;
	entry->dev = dev;
	entry->state = rx_start;
	entry->length = 0;

	usb_fill_bulk_urb (urb, dev->udev, dev->in,
		skb->data, size, rx_complete, skb);

	spin_lock_irqsave (&dev->rxq.lock, lockflags);

	if (netif_running (dev->net)
			&& netif_device_present (dev->net)
			&& !test_bit (EVENT_RX_HALT, &dev->flags)) {
		switch (retval = usb_submit_urb (urb, GFP_ATOMIC)){
		case -EPIPE:
			usbnet_defer_kevent (dev, EVENT_RX_HALT);
			break;
		case -ENOMEM:
			usbnet_defer_kevent (dev, EVENT_RX_MEMORY);
			break;
		case -ENODEV:
			if (netif_msg_ifdown (dev))
				devdbg (dev, "device gone");
			netif_device_detach (dev->net);
			break;
		default:
			if (netif_msg_rx_err (dev))
				devdbg (dev, "rx submit, %d", retval);
			tasklet_schedule (&dev->bh);
			break;
		case 0:
			__skb_queue_tail (&dev->rxq, skb);
		}
	} else {
		if (netif_msg_ifdown (dev))
			devdbg (dev, "rx: stopped");
		retval = -ENOLINK;
	}
	spin_unlock_irqrestore (&dev->rxq.lock, lockflags);
	if (retval) {
		dev_kfree_skb_any (skb);
		usb_free_urb (urb);
	}
}


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

static inline void rx_process (struct usbnet *dev, struct sk_buff *skb)
{
	if (dev->driver_info->rx_fixup
			&& !dev->driver_info->rx_fixup (dev, skb))
		goto error;
	// else network stack removes extra byte if we forced a short packet

	if (skb->len)
		usbnet_skb_return (dev, skb);
	else {
		if (netif_msg_rx_err (dev))
			devdbg (dev, "drop");
error:
		dev->stats.rx_errors++;
		skb_queue_tail (&dev->done, skb);
	}
}

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

static void rx_complete (struct urb *urb)
{
	struct sk_buff		*skb = (struct sk_buff *) urb->context;
	struct skb_data		*entry = (struct skb_data *) skb->cb;
	struct usbnet		*dev = entry->dev;
	int			urb_status = urb->status;

	skb_put (skb, urb->actual_length);
	entry->state = rx_done;
	entry->urb = NULL;

	switch (urb_status) {
	    // success
	    case 0:
		if (skb->len < dev->net->hard_header_len) {
			entry->state = rx_cleanup;
			dev->stats.rx_errors++;
			dev->stats.rx_length_errors++;
			if (netif_msg_rx_err (dev))
				devdbg (dev, "rx length %d", skb->len);
		}
		break;

	    // stalls need manual reset. this is rare ... except that
	    // when going through USB 2.0 TTs, unplug appears this way.
	    // we avoid the highspeed version of the ETIMEOUT/EILSEQ
	    // storm, recovering as needed.
	    case -EPIPE:
		dev->stats.rx_errors++;
		usbnet_defer_kevent (dev, EVENT_RX_HALT);
		// FALLTHROUGH

	    // software-driven interface shutdown
	    case -ECONNRESET:		// async unlink
	    case -ESHUTDOWN:		// hardware gone
		if (netif_msg_ifdown (dev))
			devdbg (dev, "rx shutdown, code %d", urb_status);
		goto block;

	    // we get controller i/o faults during khubd disconnect() delays.
	    // throttle down resubmits, to avoid log floods; just temporarily,
	    // so we still recover when the fault isn't a khubd delay.
	    case -EPROTO:
	    case -ETIME:
	    case -EILSEQ:
		dev->stats.rx_errors++;
		if (!timer_pending (&dev->delay)) {
			mod_timer (&dev->delay, jiffies + THROTTLE_JIFFIES);
			if (netif_msg_link (dev))
				devdbg (dev, "rx throttle %d", urb_status);
		}
block: