uwb: add the i1480 WLP driver

Add the driver for the WLP capability of the Intel i1480 device.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 632 insertions, 0 deletions

diff --git a/drivers/uwb/i1480/i1480u-wlp/tx.c b/drivers/uwb/i1480/i1480u-wlp/tx.c
new file mode 100644
index 000000000000..3426bfb68240
--- /dev/null
+++ b/drivers/uwb/i1480/i1480u-wlp/tx.c
@@ -0,0 +1,632 @@
+/*
+ * WUSB Wire Adapter: WLP interface
+ * Deal with TX (massaging data to transmit, handling it)
+ *
+ * Copyright (C) 2005-2006 Intel Corporation
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ *
+ * Transmission engine. Get an skb, create from that a WLP transmit
+ * context, add a WLP TX header (which we keep prefilled in the
+ * device's instance), fill out the target-specific fields and
+ * fire it.
+ *
+ * ROADMAP:
+ *
+ *   Entry points:
+ *
+ *     i1480u_tx_release(): called by i1480u_disconnect() to release
+ *                          pending tx contexts.
+ *
+ *     i1480u_tx_cb(): callback for TX contexts (USB URBs)
+ *       i1480u_tx_destroy():
+ *
+ *     i1480u_tx_timeout(): called for timeout handling from the
+ *                          network stack.
+ *
+ *     i1480u_hard_start_xmit(): called for transmitting an skb from
+ *                               the network stack. Will interact with WLP
+ *                               substack to verify and prepare frame.
+ *       i1480u_xmit_frame(): actual transmission on hardware
+ *
+ *         i1480u_tx_create()	    Creates TX context
+ *            i1480u_tx_create_1()    For packets in 1 fragment
+ *            i1480u_tx_create_n()    For packets in >1 fragments
+ *
+ * TODO:
+ *
+ * - FIXME: rewrite using usb_sg_*(), add asynch support to
+ *          usb_sg_*(). It might not make too much sense as most of
+ *          the times the MTU will be smaller than one page...
+ */
+
+#include "i1480u-wlp.h"
+#define D_LOCAL 5
+#include <linux/uwb/debug.h>
+
+enum {
+	/* This is only for Next and Last TX packets */
+	i1480u_MAX_PL_SIZE = i1480u_MAX_FRG_SIZE
+		- sizeof(struct untd_hdr_rst),
+};
+
+/** Free resources allocated to a i1480u tx context. */
+static
+void i1480u_tx_free(struct i1480u_tx *wtx)
+{
+	kfree(wtx->buf);
+	if (wtx->skb)
+		dev_kfree_skb_irq(wtx->skb);
+	usb_free_urb(wtx->urb);
+	kfree(wtx);
+}
+
+static
+void i1480u_tx_destroy(struct i1480u *i1480u, struct i1480u_tx *wtx)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&i1480u->tx_list_lock, flags);	/* not active any more */
+	list_del(&wtx->list_node);
+	i1480u_tx_free(wtx);
+	spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
+}
+
+static
+void i1480u_tx_unlink_urbs(struct i1480u *i1480u)
+{
+	unsigned long flags;
+	struct i1480u_tx *wtx, *next;
+
+	spin_lock_irqsave(&i1480u->tx_list_lock, flags);
+	list_for_each_entry_safe(wtx, next, &i1480u->tx_list, list_node) {
+		usb_unlink_urb(wtx->urb);
+	}
+	spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
+}
+
+
+/**
+ * Callback for a completed tx USB URB.
+ *
+ * TODO:
+ *
+ * - FIXME: recover errors more gracefully
+ * - FIXME: handle NAKs (I dont think they come here) for flow ctl
+ */
+static
+void i1480u_tx_cb(struct urb *urb)
+{
+	struct i1480u_tx *wtx = urb->context;
+	struct i1480u *i1480u = wtx->i1480u;
+	struct net_device *net_dev = i1480u->net_dev;
+	struct device *dev = &i1480u->usb_iface->dev;
+	unsigned long flags;
+
+	switch (urb->status) {
+	case 0:
+		spin_lock_irqsave(&i1480u->lock, flags);
+		i1480u->stats.tx_packets++;
+		i1480u->stats.tx_bytes += urb->actual_length;
+		spin_unlock_irqrestore(&i1480u->lock, flags);
+		break;
+	case -ECONNRESET:	/* Not an error, but a controlled situation; */
+	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
+		dev_dbg(dev, "notif endp: reset/noent %d\n", urb->status);
+		netif_stop_queue(net_dev);
+		break;
+	case -ESHUTDOWN:	/* going away! */
+		dev_dbg(dev, "notif endp: down %d\n", urb->status);
+		netif_stop_queue(net_dev);
+		break;
+	default:
+		dev_err(dev, "TX: unknown URB status %d\n", urb->status);
+		if (edc_inc(&i1480u->tx_errors, EDC_MAX_ERRORS,
+					EDC_ERROR_TIMEFRAME)) {
+			dev_err(dev, "TX: max acceptable errors exceeded."
+					"Reset device.\n");
+			netif_stop_queue(net_dev);
+			i1480u_tx_unlink_urbs(i1480u);
+			wlp_reset_all(&i1480u->wlp);
+		}
+		break;
+	}
+	i1480u_tx_destroy(i1480u, wtx);
+	if (atomic_dec_return(&i1480u->tx_inflight.count)
+	    <= i1480u->tx_inflight.threshold
+	    && netif_queue_stopped(net_dev)
+	    && i1480u->tx_inflight.threshold != 0) {
+		if (d_test(2) && printk_ratelimit())
+			d_printf(2, dev, "Restart queue. \n");
+		netif_start_queue(net_dev);
+		atomic_inc(&i1480u->tx_inflight.restart_count);
+	}
+	return;
+}
+
+
+/**
+ * Given a buffer that doesn't fit in a single fragment, create an
+ * scatter/gather structure for delivery to the USB pipe.
+ *
+ * Implements functionality of i1480u_tx_create().
+ *
+ * @wtx:	tx descriptor
+ * @skb:	skb to send
+ * @gfp_mask:	gfp allocation mask
+ * @returns:    Pointer to @wtx if ok, NULL on error.
+ *
+ * Sorry, TOO LONG a function, but breaking it up is kind of hard
+ *
+ * This will break the buffer in chunks smaller than
+ * i1480u_MAX_FRG_SIZE (including the header) and add proper headers
+ * to each:
+ *
+ *   1st header           \
+ *   i1480 tx header      |  fragment 1
+ *   fragment data        /
+ *   nxt header           \  fragment 2
+ *   fragment data        /
+ *   ..
+ *   ..
+ *   last header          \  fragment 3
+ *   last fragment data   /
+ *
+ * This does not fill the i1480 TX header, it is left up to the
+ * caller to do that; you can get it from @wtx->wlp_tx_hdr.
+ *
+ * This function consumes the skb unless there is an error.
+ */
+static
+int i1480u_tx_create_n(struct i1480u_tx *wtx, struct sk_buff *skb,
+		       gfp_t gfp_mask)
+{
+	int result;
+	void *pl;
+	size_t pl_size;
+
+	void *pl_itr, *buf_itr;
+	size_t pl_size_left, frgs, pl_size_1st, frg_pl_size = 0;
+	struct untd_hdr_1st *untd_hdr_1st;
+	struct wlp_tx_hdr *wlp_tx_hdr;
+	struct untd_hdr_rst *untd_hdr_rst;
+
+	wtx->skb = NULL;
+	pl = skb->data;
+	pl_itr = pl;
+	pl_size = skb->len;
+	pl_size_left = pl_size;	/* payload size */
+	/* First fragment; fits as much as i1480u_MAX_FRG_SIZE minus
+	 * the headers */
+	pl_size_1st = i1480u_MAX_FRG_SIZE
+		- sizeof(struct untd_hdr_1st) - sizeof(struct wlp_tx_hdr);
+	BUG_ON(pl_size_1st > pl_size);
+	pl_size_left -= pl_size_1st;
+	/* The rest have an smaller header (no i1480 TX header). We
+	 * need to break up the payload in blocks smaller than
+	 * i1480u_MAX_PL_SIZE (payload excluding header). */
+	frgs = (pl_size_left + i1480u_MAX_PL_SIZE - 1) / i1480u_MAX_PL_SIZE;
+	/* Allocate space for the new buffer. In this new buffer we'll
+	 * place the headers followed by the data fragment, headers,
+	 * data fragments, etc..
+	 */
+	result = -ENOMEM;
+	wtx->buf_size = sizeof(*untd_hdr_1st)
+		+ sizeof(*wlp_tx_hdr)
+		+ frgs * sizeof(*untd_hdr_rst)
+		+ pl_size;
+	wtx->buf = kmalloc(wtx->buf_size, gfp_mask);
+	if (wtx->buf == NULL)
+		goto error_buf_alloc;
+
+	buf_itr = wtx->buf;		/* We got the space, let's fill it up */
+	/* Fill 1st fragment */
+	untd_hdr_1st = buf_itr;
+	buf_itr += sizeof(*untd_hdr_1st);
+	untd_hdr_set_type(&untd_hdr_1st->hdr, i1480u_PKT_FRAG_1ST);
+	untd_hdr_set_rx_tx(&untd_hdr_1st->hdr, 0);
+	untd_hdr_1st->hdr.len = cpu_to_le16(pl_size + sizeof(*wlp_tx_hdr));
+	untd_hdr_1st->fragment_len =
+		cpu_to_le16(pl_size_1st + sizeof(*wlp_tx_hdr));
+	memset(untd_hdr_1st->padding, 0, sizeof(untd_hdr_1st->padding));
+	/* Set up i1480 header info */
+	wlp_tx_hdr = wtx->wlp_tx_hdr = buf_itr;
+	buf_itr += sizeof(*wlp_tx_hdr);
+	/* Copy the first fragment */
+	memcpy(buf_itr, pl_itr, pl_size_1st);
+	pl_itr += pl_size_1st;
+	buf_itr += pl_size_1st;
+
+	/* Now do each remaining fragment */
+	result = -EINVAL;
+	while (pl_size_left > 0) {
+		d_printf(5, NULL, "ITR HDR: pl_size_left %zu buf_itr %zu\n",
+			 pl_size_left, buf_itr - wtx->buf);
+		if (buf_itr + sizeof(*untd_hdr_rst) - wtx->buf
+		    > wtx->buf_size) {
+			printk(KERN_ERR "BUG: no space for header\n");
+			goto error_bug;
+		}
+		d_printf(5, NULL, "ITR HDR 2: pl_size_left %zu buf_itr %zu\n",
+			 pl_size_left, buf_itr - wtx->buf);
+		untd_hdr_rst = buf_itr;
+		buf_itr += sizeof(*untd_hdr_rst);
+		if (pl_size_left > i1480u_MAX_PL_SIZE) {
+			frg_pl_size = i1480u_MAX_PL_SIZE;
+			untd_hdr_set_type(&untd_hdr_rst->hdr, i1480u_PKT_FRAG_NXT);
+		} else {
+			frg_pl_size = pl_size_left;
+			untd_hdr_set_type(&untd_hdr_rst->hdr, i1480u_PKT_FRAG_LST);
+		}
+		d_printf(5, NULL,
+			 "ITR PL: pl_size_left %zu buf_itr %zu frg_pl_size %zu\n",
+			 pl_size_left, buf_itr - wtx->buf, frg_pl_size);
+		untd_hdr_set_rx_tx(&untd_hdr_rst->hdr, 0);
+		untd_hdr_rst->hdr.len = cpu_to_le16(frg_pl_size);
+		untd_hdr_rst->padding = 0;
+		if (buf_itr + frg_pl_size - wtx->buf
+		    > wtx->buf_size) {
+			printk(KERN_ERR "BUG: no space for payload\n");
+			goto error_bug;
+		}
+		memcpy(buf_itr, pl_itr, frg_pl_size);
+		buf_itr += frg_pl_size;
+		pl_itr += frg_pl_size;
+		pl_size_left -= frg_pl_size;
+		d_printf(5, NULL,
+			 "ITR PL 2: pl_size_left %zu buf_itr %zu frg_pl_size %zu\n",
+			 pl_size_left, buf_itr - wtx->buf, frg_pl_size);
+	}
+	dev_kfree_skb_irq(skb);
+	return 0;
+
+error_bug:
+	printk(KERN_ERR
+	       "BUG: skb %u bytes\n"
+	       "BUG: frg_pl_size %zd i1480u_MAX_FRG_SIZE %u\n"
+	       "BUG: buf_itr %zu buf_size %zu pl_size_left %zu\n",
+	       skb->len,
+	       frg_pl_size, i1480u_MAX_FRG_SIZE,
+	       buf_itr - wtx->buf, wtx->buf_size, pl_size_left);
+
+	kfree(wtx->buf);
+error_buf_alloc:
+	return result;
+}
+
+
+/**
+ * Given a buffer that fits in a single fragment, fill out a @wtx
+ * struct for transmitting it down the USB pipe.
+ *
+ * Uses the fact that we have space reserved in front of the skbuff
+ * for hardware headers :]
+ *
+ * This does not fill the i1480 TX header, it is left up to the
+ * caller to do that; you can get it from @wtx->wlp_tx_hdr.
+ *
+ * @pl:		pointer to payload data
+ * @pl_size:    size of the payuload
+ *
+ * This function does not consume the @skb.
+ */
+static
+int i1480u_tx_create_1(struct i1480u_tx *wtx, struct sk_buff *skb,
+		       gfp_t gfp_mask)
+{
+	struct untd_hdr_cmp *untd_hdr_cmp;
+	struct wlp_tx_hdr *wlp_tx_hdr;
+
+	wtx->buf = NULL;
+	wtx->skb = skb;
+	BUG_ON(skb_headroom(skb) < sizeof(*wlp_tx_hdr));
+	wlp_tx_hdr = (void *) __skb_push(skb, sizeof(*wlp_tx_hdr));
+	wtx->wlp_tx_hdr = wlp_tx_hdr;
+	BUG_ON(skb_headroom(skb) < sizeof(*untd_hdr_cmp));
+	untd_hdr_cmp = (void *) __skb_push(skb, sizeof(*untd_hdr_cmp));
+
+	untd_hdr_set_type(&untd_hdr_cmp->hdr, i1480u_PKT_FRAG_CMP);
+	untd_hdr_set_rx_tx(&untd_hdr_cmp->hdr, 0);
+	untd_hdr_cmp->hdr.len = cpu_to_le16(skb->len - sizeof(*untd_hdr_cmp));
+	untd_hdr_cmp->padding = 0;
+	return 0;
+}
+
+
+/**
+ * Given a skb to transmit, massage it to become palatable for the TX pipe
+ *
+ * This will break the buffer in chunks smaller than
+ * i1480u_MAX_FRG_SIZE and add proper headers to each.
+ *
+ *   1st header           \
+ *   i1480 tx header      |  fragment 1
+ *   fragment data        /
+ *   nxt header           \  fragment 2
+ *   fragment data        /
+ *   ..
+ *   ..
+ *   last header          \  fragment 3
+ *   last fragment data   /
+ *
+ * Each fragment will be always smaller or equal to i1480u_MAX_FRG_SIZE.
+ *
+ * If the first fragment is smaller than i1480u_MAX_FRG_SIZE, then the
+ * following is composed:
+ *
+ *   complete header      \
+ *   i1480 tx header      | single fragment
+ *   packet data          /
+ *
+ * We were going to use s/g support, but because the interface is
+ * synch and at the end there is plenty of overhead to do it, it
+ * didn't seem that worth for data that is going to be smaller than
+ * one page.
+ */
+static
+struct i1480u_tx *i1480u_tx_create(struct i1480u *i1480u,
+				   struct sk_buff *skb, gfp_t gfp_mask)
+{
+	int result;
+	struct usb_endpoint_descriptor *epd;
+	int usb_pipe;
+	unsigned long flags;
+
+	struct i1480u_tx *wtx;
+	const size_t pl_max_size =
+		i1480u_MAX_FRG_SIZE - sizeof(struct untd_hdr_cmp)
+		- sizeof(struct wlp_tx_hdr);
+
+	wtx = kmalloc(sizeof(*wtx), gfp_mask);
+	if (wtx == NULL)
+		goto error_wtx_alloc;
+	wtx->urb = usb_alloc_urb(0, gfp_mask);
+	if (wtx->urb == NULL)
+		goto error_urb_alloc;
+	epd = &i1480u->usb_iface->cur_altsetting->endpoint[2].desc;
+	usb_pipe = usb_sndbulkpipe(i1480u->usb_dev, epd->bEndpointAddress);
+	/* Fits in a single complete packet or need to split? */
+	if (skb->len > pl_max_size) {
+		result = i1480u_tx_create_n(wtx, skb, gfp_mask);
+		if (result < 0)
+			goto error_create;
+		usb_fill_bulk_urb(wtx->urb, i1480u->usb_dev, usb_pipe,
+				  wtx->buf, wtx->buf_size, i1480u_tx_cb, wtx);
+	} else {
+		result = i1480u_tx_create_1(wtx, skb, gfp_mask);
+		if (result < 0)
+			goto error_create;
+		usb_fill_bulk_urb(wtx->urb, i1480u->usb_dev, usb_pipe,
+				  skb->data, skb->len, i1480u_tx_cb, wtx);
+	}
+	spin_lock_irqsave(&i1480u->tx_list_lock, flags);
+	list_add(&wtx->list_node, &i1480u->tx_list);
+	spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
+	return wtx;
+
+error_create:
+	kfree(wtx->urb);
+error_urb_alloc:
+	kfree(wtx);
+error_wtx_alloc:
+	return NULL;
+}
+
+/**
+ * Actual fragmentation and transmission of frame
+ *
+ * @wlp:  WLP substack data structure
+ * @skb:  To be transmitted
+ * @dst:  Device address of destination
+ * @returns: 0 on success, <0 on failure
+ *
+ * This function can also be called directly (not just from
+ * hard_start_xmit), so we also check here if the interface is up before
+ * taking sending anything.
+ */
+int i1480u_xmit_frame(struct wlp *wlp, struct sk_buff *skb,
+		      struct uwb_dev_addr *dst)
+{
+	int result = -ENXIO;
+	struct i1480u *i1480u = container_of(wlp, struct i1480u, wlp);
+	struct device *dev = &i1480u->usb_iface->dev;
+	struct net_device *net_dev = i1480u->net_dev;
+	struct i1480u_tx *wtx;
+	struct wlp_tx_hdr *wlp_tx_hdr;
+	static unsigned char dev_bcast[2] = { 0xff, 0xff };
+#if 0
+	int lockup = 50;
+#endif
+
+	d_fnstart(6, dev, "(skb %p (%u), net_dev %p)\n", skb, skb->len,
+		  net_dev);
+	BUG_ON(i1480u->wlp.rc == NULL);
+	if ((net_dev->flags & IFF_UP) == 0)
+		goto out;
+	result = -EBUSY;
+	if (atomic_read(&i1480u->tx_inflight.count) >= i1480u->tx_inflight.max) {
+		if (d_test(2) && printk_ratelimit())
+			d_printf(2, dev, "Max frames in flight "
+				 "stopping queue.\n");
+		netif_stop_queue(net_dev);
+		goto error_max_inflight;
+	}
+	result = -ENOMEM;
+	wtx = i1480u_tx_create(i1480u, skb, GFP_ATOMIC);
+	if (unlikely(wtx == NULL)) {
+		if (printk_ratelimit())
+			dev_err(dev, "TX: no memory for WLP TX URB,"
+				"dropping packet (in flight %d)\n",
+				atomic_read(&i1480u->tx_inflight.count));
+		netif_stop_queue(net_dev);
+		goto error_wtx_alloc;
+	}
+	wtx->i1480u = i1480u;
+	/* Fill out the i1480 header; @i1480u->def_tx_hdr read without
+	 * locking. We do so because they are kind of orthogonal to
+	 * each other (and thus not changed in an atomic batch).
+	 * The ETH header is right after the WLP TX header. */
+	wlp_tx_hdr = wtx->wlp_tx_hdr;
+	*wlp_tx_hdr = i1480u->options.def_tx_hdr;
+	wlp_tx_hdr->dstaddr = *dst;
+	if (!memcmp(&wlp_tx_hdr->dstaddr, dev_bcast, sizeof(dev_bcast))
+	    && (wlp_tx_hdr_delivery_id_type(wlp_tx_hdr) & WLP_DRP)) {
+		/*Broadcast message directed to DRP host. Send as best effort
+		 * on PCA. */
+		wlp_tx_hdr_set_delivery_id_type(wlp_tx_hdr, i1480u->options.pca_base_priority);
+	}
+
+#if 0
+	dev_info(dev, "TX delivering skb -> USB, %zu bytes\n", skb->len);
+	dump_bytes(dev, skb->data, skb->len > 72 ? 72 : skb->len);
+#endif
+#if 0
+	/* simulates a device lockup after every lockup# packets */
+	if (lockup && ((i1480u->stats.tx_packets + 1) % lockup) == 0) {
+		/* Simulate a dropped transmit interrupt */
+		net_dev->trans_start = jiffies;
+		netif_stop_queue(net_dev);
+		dev_err(dev, "Simulate lockup at %ld\n", jiffies);
+		return result;
+	}
+#endif
+
+	result = usb_submit_urb(wtx->urb, GFP_ATOMIC);		/* Go baby */
+	if (result < 0) {
+		dev_err(dev, "TX: cannot submit URB: %d\n", result);
+		/* We leave the freeing of skb to calling function */
+		wtx->skb = NULL;
+		goto error_tx_urb_submit;
+	}
+	atomic_inc(&i1480u->tx_inflight.count);
+	net_dev->trans_start = jiffies;
+	d_fnend(6, dev, "(skb %p (%u), net_dev %p) = %d\n", skb, skb->len,
+		net_dev, result);
+	return result;
+
+error_tx_urb_submit:
+	i1480u_tx_destroy(i1480u, wtx);
+error_wtx_alloc:
+error_max_inflight:
+out:
+	d_fnend(6, dev, "(skb %p (%u), net_dev %p) = %d\n", skb, skb->len,
+		net_dev, result);
+	return result;
+}
+
+
+/**
+ * Transmit an skb  Called when an skbuf has to be transmitted
+ *
+ * The skb is first passed to WLP substack to ensure this is a valid
+ * frame. If valid the device address of destination will be filled and
+ * the WLP header prepended to the skb. If this step fails we fake sending
+ * the frame, if we return an error the network stack will just keep trying.
+ *
+ * Broadcast frames inside a WSS needs to be treated special as multicast is
+ * not supported. A broadcast frame is sent as unicast to each member of the
+ * WSS - this is done by the WLP substack when it finds a broadcast frame.
+ * So, we test if the WLP substack took over the skb and only transmit it
+ * if it has not (been taken over).
+ *
+ * @net_dev->xmit_lock is held
+ */
+int i1480u_hard_start_xmit(struct sk_buff *skb, struct net_device *net_dev)
+{
+	int result;
+	struct i1480u *i1480u = netdev_priv(net_dev);
+	struct device *dev = &i1480u->usb_iface->dev;
+	struct uwb_dev_addr dst;
+
+	d_fnstart(6, dev, "(skb %p (%u), net_dev %p)\n", skb, skb->len,
+		  net_dev);
+	BUG_ON(i1480u->wlp.rc == NULL);
+	if ((net_dev->flags & IFF_UP) == 0)
+		goto error;
+	result = wlp_prepare_tx_frame(dev, &i1480u->wlp, skb, &dst);
+	if (result < 0) {
+		dev_err(dev, "WLP verification of TX frame failed (%d). "
+			"Dropping packet.\n", result);
+		goto error;
+	} else if (result == 1) {
+		d_printf(6, dev, "WLP will transmit frame. \n");
+		/* trans_start time will be set when WLP actually transmits
+		 * the frame */
+		goto out;
+	}
+	d_printf(6, dev, "Transmitting frame. \n");
+	result = i1480u_xmit_frame(&i1480u->wlp, skb, &dst);
+	if (result < 0) {
+		dev_err(dev, "Frame TX failed (%d).\n", result);
+		goto error;
+	}
+	d_fnend(6, dev, "(skb %p (%u), net_dev %p) = %d\n", skb, skb->len,
+		net_dev, result);
+	return NETDEV_TX_OK;
+error:
+	dev_kfree_skb_any(skb);
+	i1480u->stats.tx_dropped++;
+out:
+	d_fnend(6, dev, "(skb %p (%u), net_dev %p) = %d\n", skb, skb->len,
+		net_dev, result);
+	return NETDEV_TX_OK;
+}
+
+
+/**
+ * Called when a pkt transmission doesn't complete in a reasonable period
+ * Device reset may sleep - do it outside of interrupt context (delayed)
+ */
+void i1480u_tx_timeout(struct net_device *net_dev)
+{
+	struct i1480u *i1480u = netdev_priv(net_dev);
+
+	wlp_reset_all(&i1480u->wlp);
+}
+
+
+void i1480u_tx_release(struct i1480u *i1480u)
+{
+	unsigned long flags;
+	struct i1480u_tx *wtx, *next;
+	int count = 0, empty;
+
+	spin_lock_irqsave(&i1480u->tx_list_lock, flags);
+	list_for_each_entry_safe(wtx, next, &i1480u->tx_list, list_node) {
+		count++;
+		usb_unlink_urb(wtx->urb);
+	}
+	spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
+	count = count*10; /* i1480ut 200ms per unlinked urb (intervals of 20ms) */
+	/*
+	 * We don't like this sollution too much (dirty as it is), but
+	 * it is cheaper than putting a refcount on each i1480u_tx and
+	 * i1480uting for all of them to go away...
+	 *
+	 * Called when no more packets can be added to tx_list
+	 * so can i1480ut for it to be empty.
+	 */
+	while (1) {
+		spin_lock_irqsave(&i1480u->tx_list_lock, flags);
+		empty = list_empty(&i1480u->tx_list);
+		spin_unlock_irqrestore(&i1480u->tx_list_lock, flags);
+		if (empty)
+			break;
+		count--;
+		BUG_ON(count == 0);
+		msleep(20);
+	}
+}