wusb: add the Wire Adapter (WA) core

Common code for supporting Host Wire Adapters and Device Wire Adapters.

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

1 files changed, 1709 insertions, 0 deletions

diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c
new file mode 100644
index 0000000..7d192f3
--- /dev/null
+++ b/drivers/usb/wusbcore/wa-xfer.c
@@ -0,0 +1,1709 @@
+/*
+ * WUSB Wire Adapter
+ * Data transfer and URB enqueing
+ *
+ * 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.
+ *
+ *
+ * How transfers work: get a buffer, break it up in segments (segment
+ * size is a multiple of the maxpacket size). For each segment issue a
+ * segment request (struct wa_xfer_*), then send the data buffer if
+ * out or nothing if in (all over the DTO endpoint).
+ *
+ * For each submitted segment request, a notification will come over
+ * the NEP endpoint and a transfer result (struct xfer_result) will
+ * arrive in the DTI URB. Read it, get the xfer ID, see if there is
+ * data coming (inbound transfer), schedule a read and handle it.
+ *
+ * Sounds simple, it is a pain to implement.
+ *
+ *
+ * ENTRY POINTS
+ *
+ *   FIXME
+ *
+ * LIFE CYCLE / STATE DIAGRAM
+ *
+ *   FIXME
+ *
+ * THIS CODE IS DISGUSTING
+ *
+ *   Warned you are; it's my second try and still not happy with it.
+ *
+ * NOTES:
+ *
+ *   - No iso
+ *
+ *   - Supports DMA xfers, control, bulk and maybe interrupt
+ *
+ *   - Does not recycle unused rpipes
+ *
+ *     An rpipe is assigned to an endpoint the first time it is used,
+ *     and then it's there, assigned, until the endpoint is disabled
+ *     (destroyed [{h,d}wahc_op_ep_disable()]. The assignment of the
+ *     rpipe to the endpoint is done under the wa->rpipe_sem semaphore
+ *     (should be a mutex).
+ *
+ *     Two methods it could be done:
+ *
+ *     (a) set up a timer everytime an rpipe's use count drops to 1
+ *         (which means unused) or when a transfer ends. Reset the
+ *         timer when a xfer is queued. If the timer expires, release
+ *         the rpipe [see rpipe_ep_disable()].
+ *
+ *     (b) when looking for free rpipes to attach [rpipe_get_by_ep()],
+ *         when none are found go over the list, check their endpoint
+ *         and their activity record (if no last-xfer-done-ts in the
+ *         last x seconds) take it
+ *
+ *     However, due to the fact that we have a set of limited
+ *     resources (max-segments-at-the-same-time per xfer,
+ *     xfers-per-ripe, blocks-per-rpipe, rpipes-per-host), at the end
+ *     we are going to have to rebuild all this based on an scheduler,
+ *     to where we have a list of transactions to do and based on the
+ *     availability of the different requried components (blocks,
+ *     rpipes, segment slots, etc), we go scheduling them. Painful.
+ */
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/hash.h>
+#include "wa-hc.h"
+#include "wusbhc.h"
+
+#undef D_LOCAL
+#define D_LOCAL 0 /* 0 disabled, > 0 different levels... */
+#include <linux/uwb/debug.h>
+
+enum {
+	WA_SEGS_MAX = 255,
+};
+
+enum wa_seg_status {
+	WA_SEG_NOTREADY,
+	WA_SEG_READY,
+	WA_SEG_DELAYED,
+	WA_SEG_SUBMITTED,
+	WA_SEG_PENDING,
+	WA_SEG_DTI_PENDING,
+	WA_SEG_DONE,
+	WA_SEG_ERROR,
+	WA_SEG_ABORTED,
+};
+
+static void wa_xfer_delayed_run(struct wa_rpipe *);
+
+/*
+ * Life cycle governed by 'struct urb' (the refcount of the struct is
+ * that of the 'struct urb' and usb_free_urb() would free the whole
+ * struct).
+ */
+struct wa_seg {
+	struct urb urb;
+	struct urb *dto_urb;		/* for data output? */
+	struct list_head list_node;	/* for rpipe->req_list */
+	struct wa_xfer *xfer;		/* out xfer */
+	u8 index;			/* which segment we are */
+	enum wa_seg_status status;
+	ssize_t result;			/* bytes xfered or error */
+	struct wa_xfer_hdr xfer_hdr;
+	u8 xfer_extra[];		/* xtra space for xfer_hdr_ctl */
+};
+
+static void wa_seg_init(struct wa_seg *seg)
+{
+	/* usb_init_urb() repeats a lot of work, so we do it here */
+	kref_init(&seg->urb.kref);
+}
+
+/*
+ * Protected by xfer->lock
+ *
+ */
+struct wa_xfer {
+	struct kref refcnt;
+	struct list_head list_node;
+	spinlock_t lock;
+	u32 id;
+
+	struct wahc *wa;		/* Wire adapter we are plugged to */
+	struct usb_host_endpoint *ep;
+	struct urb *urb;		/* URB we are transfering for */
+	struct wa_seg **seg;		/* transfer segments */
+	u8 segs, segs_submitted, segs_done;
+	unsigned is_inbound:1;
+	unsigned is_dma:1;
+	size_t seg_size;
+	int result;
+
+	gfp_t gfp;			/* allocation mask */
+
+	struct wusb_dev *wusb_dev;	/* for activity timestamps */
+};
+
+static inline void wa_xfer_init(struct wa_xfer *xfer)
+{
+	kref_init(&xfer->refcnt);
+	INIT_LIST_HEAD(&xfer->list_node);
+	spin_lock_init(&xfer->lock);
+}
+
+/*
+ * Destory a transfer structure
+ *
+ * Note that the xfer->seg[index] thingies follow the URB life cycle,
+ * so we need to put them, not free them.
+ */
+static void wa_xfer_destroy(struct kref *_xfer)
+{
+	struct wa_xfer *xfer = container_of(_xfer, struct wa_xfer, refcnt);
+	if (xfer->seg) {
+		unsigned cnt;
+		for (cnt = 0; cnt < xfer->segs; cnt++) {
+			if (xfer->is_inbound)
+				usb_put_urb(xfer->seg[cnt]->dto_urb);
+			usb_put_urb(&xfer->seg[cnt]->urb);
+		}
+	}
+	kfree(xfer);
+	d_printf(2, NULL, "xfer %p destroyed\n", xfer);
+}
+
+static void wa_xfer_get(struct wa_xfer *xfer)
+{
+	kref_get(&xfer->refcnt);
+}
+
+static void wa_xfer_put(struct wa_xfer *xfer)
+{
+	d_fnstart(3, NULL, "(xfer %p) -- ref count bef put %d\n",
+		    xfer, atomic_read(&xfer->refcnt.refcount));
+	kref_put(&xfer->refcnt, wa_xfer_destroy);
+	d_fnend(3, NULL, "(xfer %p) = void\n", xfer);
+}
+
+/*
+ * xfer is referenced
+ *
+ * xfer->lock has to be unlocked
+ *
+ * We take xfer->lock for setting the result; this is a barrier
+ * against drivers/usb/core/hcd.c:unlink1() being called after we call
+ * usb_hcd_giveback_urb() and wa_urb_dequeue() trying to get a
+ * reference to the transfer.
+ */
+static void wa_xfer_giveback(struct wa_xfer *xfer)
+{
+	unsigned long flags;
+	d_fnstart(3, NULL, "(xfer %p)\n", xfer);
+	spin_lock_irqsave(&xfer->wa->xfer_list_lock, flags);
+	list_del_init(&xfer->list_node);
+	spin_unlock_irqrestore(&xfer->wa->xfer_list_lock, flags);
+	/* FIXME: segmentation broken -- kills DWA */
+	wusbhc_giveback_urb(xfer->wa->wusb, xfer->urb, xfer->result);
+	wa_put(xfer->wa);
+	wa_xfer_put(xfer);
+	d_fnend(3, NULL, "(xfer %p) = void\n", xfer);
+}
+
+/*
+ * xfer is referenced
+ *
+ * xfer->lock has to be unlocked
+ */
+static void wa_xfer_completion(struct wa_xfer *xfer)
+{
+	d_fnstart(3, NULL, "(xfer %p)\n", xfer);
+	if (xfer->wusb_dev)
+		wusb_dev_put(xfer->wusb_dev);
+	rpipe_put(xfer->ep->hcpriv);
+	wa_xfer_giveback(xfer);
+	d_fnend(3, NULL, "(xfer %p) = void\n", xfer);
+	return;
+}
+
+/*
+ * If transfer is done, wrap it up and return true
+ *
+ * xfer->lock has to be locked
+ */
+static unsigned __wa_xfer_is_done(struct wa_xfer *xfer)
+{
+	unsigned result, cnt;
+	struct wa_seg *seg;
+	struct urb *urb = xfer->urb;
+	unsigned found_short = 0;
+
+	d_fnstart(3, NULL, "(xfer %p)\n", xfer);
+	result = xfer->segs_done == xfer->segs_submitted;
+	if (result == 0)
+		goto out;
+	urb->actual_length = 0;
+	for (cnt = 0; cnt < xfer->segs; cnt++) {
+		seg = xfer->seg[cnt];
+		switch (seg->status) {
+		case WA_SEG_DONE:
+			if (found_short && seg->result > 0) {
+				if (printk_ratelimit())
+					printk(KERN_ERR "xfer %p#%u: bad short "
+					       "segments (%zu)\n", xfer, cnt,
+					       seg->result);
+				urb->status = -EINVAL;
+				goto out;
+			}
+			urb->actual_length += seg->result;
+			if (seg->result < xfer->seg_size
+			    && cnt != xfer->segs-1)
+				found_short = 1;
+			d_printf(2, NULL, "xfer %p#%u: DONE short %d "
+				 "result %zu urb->actual_length %d\n",
+				 xfer, seg->index, found_short, seg->result,
+				 urb->actual_length);
+			break;
+		case WA_SEG_ERROR:
+			xfer->result = seg->result;
+			d_printf(2, NULL, "xfer %p#%u: ERROR result %zu\n",
+				 xfer, seg->index, seg->result);
+			goto out;
+		case WA_SEG_ABORTED:
+			WARN_ON(urb->status != -ECONNRESET
+				&& urb->status != -ENOENT);
+			d_printf(2, NULL, "xfer %p#%u ABORTED: result %d\n",
+				 xfer, seg->index, urb->status);
+			xfer->result = urb->status;
+			goto out;
+		default:
+			/* if (printk_ratelimit()) */
+				printk(KERN_ERR "xfer %p#%u: "
+				       "is_done bad state %d\n",
+				       xfer, cnt, seg->status);
+			xfer->result = -EINVAL;
+			WARN_ON(1);
+			goto out;
+		}
+	}
+	xfer->result = 0;
+out:
+	d_fnend(3, NULL, "(xfer %p) = void\n", xfer);
+	return result;
+}
+
+/*
+ * Initialize a transfer's ID
+ *
+ * We need to use a sequential number; if we use the pointer or the
+ * hash of the pointer, it can repeat over sequential transfers and
+ * then it will confuse the HWA....wonder why in hell they put a 32
+ * bit handle in there then.
+ */
+static void wa_xfer_id_init(struct wa_xfer *xfer)
+{
+	xfer->id = atomic_add_return(1, &xfer->wa->xfer_id_count);
+}
+
+/*
+ * Return the xfer's ID associated with xfer
+ *
+ * Need to generate a
+ */
+static u32 wa_xfer_id(struct wa_xfer *xfer)
+{
+	return xfer->id;
+}
+
+/*
+ * Search for a transfer list ID on the HCD's URB list
+ *
+ * For 32 bit architectures, we use the pointer itself; for 64 bits, a
+ * 32-bit hash of the pointer.
+ *
+ * @returns NULL if not found.
+ */
+static struct wa_xfer *wa_xfer_get_by_id(struct wahc *wa, u32 id)
+{
+	unsigned long flags;
+	struct wa_xfer *xfer_itr;
+	spin_lock_irqsave(&wa->xfer_list_lock, flags);
+	list_for_each_entry(xfer_itr, &wa->xfer_list, list_node) {
+		if (id == xfer_itr->id) {
+			wa_xfer_get(xfer_itr);
+			goto out;
+		}
+	}
+	xfer_itr = NULL;
+out:
+	spin_unlock_irqrestore(&wa->xfer_list_lock, flags);
+	return xfer_itr;
+}
+
+struct wa_xfer_abort_buffer {
+	struct urb urb;
+	struct wa_xfer_abort cmd;
+};
+
+static void __wa_xfer_abort_cb(struct urb *urb)
+{
+	struct wa_xfer_abort_buffer *b = urb->context;
+	usb_put_urb(&b->urb);
+}
+
+/*
+ * Aborts an ongoing transaction
+ *
+ * Assumes the transfer is referenced and locked and in a submitted
+ * state (mainly that there is an endpoint/rpipe assigned).
+ *
+ * The callback (see above) does nothing but freeing up the data by
+ * putting the URB. Because the URB is allocated at the head of the
+ * struct, the whole space we allocated is kfreed.
+ *
+ * We'll get an 'aborted transaction' xfer result on DTI, that'll
+ * politely ignore because at this point the transaction has been
+ * marked as aborted already.
+ */
+static void __wa_xfer_abort(struct wa_xfer *xfer)
+{
+	int result;
+	struct device *dev = &xfer->wa->usb_iface->dev;
+	struct wa_xfer_abort_buffer *b;
+	struct wa_rpipe *rpipe = xfer->ep->hcpriv;
+
+	b = kmalloc(sizeof(*b), GFP_ATOMIC);
+	if (b == NULL)
+		goto error_kmalloc;
+	b->cmd.bLength =  sizeof(b->cmd);
+	b->cmd.bRequestType = WA_XFER_ABORT;
+	b->cmd.wRPipe = rpipe->descr.wRPipeIndex;
+	b->cmd.dwTransferID = wa_xfer_id(xfer);
+
+	usb_init_urb(&b->urb);
+	usb_fill_bulk_urb(&b->urb, xfer->wa->usb_dev,
+		usb_sndbulkpipe(xfer->wa->usb_dev,
+				xfer->wa->dto_epd->bEndpointAddress),
+		&b->cmd, sizeof(b->cmd), __wa_xfer_abort_cb, b);
+	result = usb_submit_urb(&b->urb, GFP_ATOMIC);
+	if (result < 0)
+		goto error_submit;
+	return;				/* callback frees! */
+
+
+error_submit:
+	if (printk_ratelimit())
+		dev_err(dev, "xfer %p: Can't submit abort request: %d\n",
+			xfer, result);
+	kfree(b);
+error_kmalloc:
+	return;
+
+}
+
+/*
+ *
+ * @returns < 0 on error, transfer segment request size if ok
+ */
+static ssize_t __wa_xfer_setup_sizes(struct wa_xfer *xfer,
+				     enum wa_xfer_type *pxfer_type)
+{
+	ssize_t result;
+	struct device *dev = &xfer->wa->usb_iface->dev;
+	size_t maxpktsize;
+	struct urb *urb = xfer->urb;
+	struct wa_rpipe *rpipe = xfer->ep->hcpriv;
+
+	d_fnstart(3, dev, "(xfer %p [rpipe %p] urb %p)\n",
+		  xfer, rpipe, urb);
+	switch (rpipe->descr.bmAttribute & 0x3) {
+	case USB_ENDPOINT_XFER_CONTROL:
+		*pxfer_type = WA_XFER_TYPE_CTL;
+		result = sizeof(struct wa_xfer_ctl);
+		break;
+	case USB_ENDPOINT_XFER_INT:
+	case USB_ENDPOINT_XFER_BULK:
+		*pxfer_type = WA_XFER_TYPE_BI;
+		result = sizeof(struct wa_xfer_bi);
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		dev_err(dev, "FIXME: ISOC not implemented\n");
+		result = -ENOSYS;
+		goto error;
+	default:
+		/* never happens */
+		BUG();
+		result = -EINVAL;	/* shut gcc up */
+	};
+	xfer->is_inbound = urb->pipe & USB_DIR_IN ? 1 : 0;
+	xfer->is_dma = urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP ? 1 : 0;
+	xfer->seg_size = le16_to_cpu(rpipe->descr.wBlocks)
+		* 1 << (xfer->wa->wa_descr->bRPipeBlockSize - 1);
+	/* Compute the segment size and make sure it is a multiple of
+	 * the maxpktsize (WUSB1.0[8.3.3.1])...not really too much of
+	 * a check (FIXME) */
+	maxpktsize = le16_to_cpu(rpipe->descr.wMaxPacketSize);
+	if (xfer->seg_size < maxpktsize) {
+		dev_err(dev, "HW BUG? seg_size %zu smaller than maxpktsize "
+			"%zu\n", xfer->seg_size, maxpktsize);
+		result = -EINVAL;
+		goto error;
+	}
+	xfer->seg_size = (xfer->seg_size / maxpktsize) * maxpktsize;
+	xfer->segs = (urb->transfer_buffer_length + xfer->seg_size - 1)
+		/ xfer->seg_size;
+	if (xfer->segs >= WA_SEGS_MAX) {
+		dev_err(dev, "BUG? ops, number of segments %d bigger than %d\n",
+			(int)(urb->transfer_buffer_length / xfer->seg_size),
+			WA_SEGS_MAX);
+		result = -EINVAL;
+		goto error;
+	}
+	if (xfer->segs == 0 && *pxfer_type == WA_XFER_TYPE_CTL)
+		xfer->segs = 1;
+error:
+	d_fnend(3, dev, "(xfer %p [rpipe %p] urb %p) = %d\n",
+		xfer, rpipe, urb, (int)result);
+	return result;
+}
+
+/** Fill in the common request header and xfer-type specific data. */
+static void __wa_xfer_setup_hdr0(struct wa_xfer *xfer,
+				 struct wa_xfer_hdr *xfer_hdr0,
+				 enum wa_xfer_type xfer_type,
+				 size_t xfer_hdr_size)
+{
+	struct wa_rpipe *rpipe = xfer->ep->hcpriv;
+
+	xfer_hdr0 = &xfer->seg[0]->xfer_hdr;
+	xfer_hdr0->bLength = xfer_hdr_size;
+	xfer_hdr0->bRequestType = xfer_type;
+	xfer_hdr0->wRPipe = rpipe->descr.wRPipeIndex;
+	xfer_hdr0->dwTransferID = wa_xfer_id(xfer);
+	xfer_hdr0->bTransferSegment = 0;
+	switch (xfer_type) {
+	case WA_XFER_TYPE_CTL: {
+		struct wa_xfer_ctl *xfer_ctl =
+			container_of(xfer_hdr0, struct wa_xfer_ctl, hdr);
+		xfer_ctl->bmAttribute = xfer->is_inbound ? 1 : 0;
+		BUG_ON(xfer->urb->transfer_flags & URB_NO_SETUP_DMA_MAP
+		       && xfer->urb->setup_packet == NULL);
+		memcpy(&xfer_ctl->baSetupData, xfer->urb->setup_packet,
+		       sizeof(xfer_ctl->baSetupData));
+		break;
+	}
+	case WA_XFER_TYPE_BI:
+		break;
+	case WA_XFER_TYPE_ISO:
+		printk(KERN_ERR "FIXME: ISOC not implemented\n");
+	default:
+		BUG();
+	};
+}
+
+/*
+ * Callback for the OUT data phase of the segment request
+ *
+ * Check wa_seg_cb(); most comments also apply here because this
+ * function does almost the same thing and they work closely
+ * together.
+ *
+ * If the seg request has failed but this DTO phase has suceeded,
+ * wa_seg_cb() has already failed the segment and moved the
+ * status to WA_SEG_ERROR, so this will go through 'case 0' and
+ * effectively do nothing.
+ */
+static void wa_seg_dto_cb(struct urb *urb)
+{
+	struct wa_seg *seg = urb->context;
+	struct wa_xfer *xfer = seg->xfer;
+	struct wahc *wa;
+	struct device *dev;
+	struct wa_rpipe *rpipe;
+	unsigned long flags;
+	unsigned rpipe_ready = 0;
+	u8 done = 0;
+
+	d_fnstart(3, NULL, "(urb %p [%d])\n", urb, urb->status);
+	switch (urb->status) {
+	case 0:
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		d_printf(2, dev, "xfer %p#%u: data out done (%d bytes)\n",
+			   xfer, seg->index, urb->actual_length);
+		if (seg->status < WA_SEG_PENDING)
+			seg->status = WA_SEG_PENDING;
+		seg->result = urb->actual_length;
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		break;
+	case -ECONNRESET:	/* URB unlinked; no need to do anything */
+	case -ENOENT:		/* as it was done by the who unlinked us */
+		break;
+	default:		/* Other errors ... */
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		rpipe = xfer->ep->hcpriv;
+		if (printk_ratelimit())
+			dev_err(dev, "xfer %p#%u: data out error %d\n",
+				xfer, seg->index, urb->status);
+		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)){
+			dev_err(dev, "DTO: URB max acceptable errors "
+				"exceeded, resetting device\n");
+			wa_reset_all(wa);
+		}
+		if (seg->status != WA_SEG_ERROR) {
+			seg->status = WA_SEG_ERROR;
+			seg->result = urb->status;
+			xfer->segs_done++;
+			__wa_xfer_abort(xfer);
+			rpipe_ready = rpipe_avail_inc(rpipe);
+			done = __wa_xfer_is_done(xfer);
+		}
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		if (done)
+			wa_xfer_completion(xfer);
+		if (rpipe_ready)
+			wa_xfer_delayed_run(rpipe);
+	}
+	d_fnend(3, NULL, "(urb %p [%d]) = void\n", urb, urb->status);
+}
+
+/*
+ * Callback for the segment request
+ *
+ * If succesful transition state (unless already transitioned or
+ * outbound transfer); otherwise, take a note of the error, mark this
+ * segment done and try completion.
+ *
+ * Note we don't access until we are sure that the transfer hasn't
+ * been cancelled (ECONNRESET, ENOENT), which could mean that
+ * seg->xfer could be already gone.
+ *
+ * We have to check before setting the status to WA_SEG_PENDING
+ * because sometimes the xfer result callback arrives before this
+ * callback (geeeeeeze), so it might happen that we are already in
+ * another state. As well, we don't set it if the transfer is inbound,
+ * as in that case, wa_seg_dto_cb will do it when the OUT data phase
+ * finishes.
+ */
+static void wa_seg_cb(struct urb *urb)
+{
+	struct wa_seg *seg = urb->context;
+	struct wa_xfer *xfer = seg->xfer;
+	struct wahc *wa;
+	struct device *dev;
+	struct wa_rpipe *rpipe;
+	unsigned long flags;
+	unsigned rpipe_ready;
+	u8 done = 0;
+
+	d_fnstart(3, NULL, "(urb %p [%d])\n", urb, urb->status);
+	switch (urb->status) {
+	case 0:
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		d_printf(2, dev, "xfer %p#%u: request done\n",
+			   xfer, seg->index);
+		if (xfer->is_inbound && seg->status < WA_SEG_PENDING)
+			seg->status = WA_SEG_PENDING;
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		break;
+	case -ECONNRESET:	/* URB unlinked; no need to do anything */
+	case -ENOENT:		/* as it was done by the who unlinked us */
+		break;
+	default:		/* Other errors ... */
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		rpipe = xfer->ep->hcpriv;
+		if (printk_ratelimit())
+			dev_err(dev, "xfer %p#%u: request error %d\n",
+				xfer, seg->index, urb->status);
+		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)){
+			dev_err(dev, "DTO: URB max acceptable errors "
+				"exceeded, resetting device\n");
+			wa_reset_all(wa);
+		}
+		usb_unlink_urb(seg->dto_urb);
+		seg->status = WA_SEG_ERROR;
+		seg->result = urb->status;
+		xfer->segs_done++;
+		__wa_xfer_abort(xfer);
+		rpipe_ready = rpipe_avail_inc(rpipe);
+		done = __wa_xfer_is_done(xfer);
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		if (done)
+			wa_xfer_completion(xfer);
+		if (rpipe_ready)
+			wa_xfer_delayed_run(rpipe);
+	}
+	d_fnend(3, NULL, "(urb %p [%d]) = void\n", urb, urb->status);
+}
+
+/*
+ * Allocate the segs array and initialize each of them
+ *
+ * The segments are freed by wa_xfer_destroy() when the xfer use count
+ * drops to zero; however, because each segment is given the same life
+ * cycle as the USB URB it contains, it is actually freed by
+ * usb_put_urb() on the contained USB URB (twisted, eh?).
+ */
+static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
+{
+	int result, cnt;
+	size_t alloc_size = sizeof(*xfer->seg[0])
+		- sizeof(xfer->seg[0]->xfer_hdr) + xfer_hdr_size;
+	struct usb_device *usb_dev = xfer->wa->usb_dev;
+	const struct usb_endpoint_descriptor *dto_epd = xfer->wa->dto_epd;
+	struct wa_seg *seg;
+	size_t buf_itr, buf_size, buf_itr_size;
+
+	result = -ENOMEM;
+	xfer->seg = kzalloc(xfer->segs * sizeof(xfer->seg[0]), GFP_ATOMIC);
+	if (xfer->seg == NULL)
+		goto error_segs_kzalloc;
+	buf_itr = 0;
+	buf_size = xfer->urb->transfer_buffer_length;
+	for (cnt = 0; cnt < xfer->segs; cnt++) {
+		seg = xfer->seg[cnt] = kzalloc(alloc_size, GFP_ATOMIC);
+		if (seg == NULL)
+			goto error_seg_kzalloc;
+		wa_seg_init(seg);
+		seg->xfer = xfer;
+		seg->index = cnt;
+		usb_fill_bulk_urb(&seg->urb, usb_dev,
+				  usb_sndbulkpipe(usb_dev,
+						  dto_epd->bEndpointAddress),
+				  &seg->xfer_hdr, xfer_hdr_size,
+				  wa_seg_cb, seg);
+		buf_itr_size = buf_size > xfer->seg_size ?
+			xfer->seg_size : buf_size;
+		if (xfer->is_inbound == 0 && buf_size > 0) {
+			seg->dto_urb = usb_alloc_urb(0, GFP_ATOMIC);
+			if (seg->dto_urb == NULL)
+				goto error_dto_alloc;
+			usb_fill_bulk_urb(
+				seg->dto_urb, usb_dev,
+				usb_sndbulkpipe(usb_dev,
+						dto_epd->bEndpointAddress),
+				NULL, 0, wa_seg_dto_cb, seg);
+			if (xfer->is_dma) {
+				seg->dto_urb->transfer_dma =
+					xfer->urb->transfer_dma + buf_itr;
+				seg->dto_urb->transfer_flags |=
+					URB_NO_TRANSFER_DMA_MAP;
+			} else
+				seg->dto_urb->transfer_buffer =
+					xfer->urb->transfer_buffer + buf_itr;
+			seg->dto_urb->transfer_buffer_length = buf_itr_size;
+		}
+		seg->status = WA_SEG_READY;
+		buf_itr += buf_itr_size;
+		buf_size -= buf_itr_size;
+	}
+	return 0;
+
+error_dto_alloc:
+	kfree(xfer->seg[cnt]);
+	cnt--;
+error_seg_kzalloc:
+	/* use the fact that cnt is left at were it failed */
+	for (; cnt > 0; cnt--) {
+		if (xfer->is_inbound == 0)
+			kfree(xfer->seg[cnt]->dto_urb);
+		kfree(xfer->seg[cnt]);
+	}
+error_segs_kzalloc:
+	return result;
+}
+
+/*
+ * Allocates all the stuff needed to submit a transfer
+ *
+ * Breaks the whole data buffer in a list of segments, each one has a
+ * structure allocated to it and linked in xfer->seg[index]
+ *
+ * FIXME: merge setup_segs() and the last part of this function, no
+ *        need to do two for loops when we could run everything in a
+ *        single one
+ */
+static int __wa_xfer_setup(struct wa_xfer *xfer, struct urb *urb)
+{
+	int result;
+	struct device *dev = &xfer->wa->usb_iface->dev;
+	enum wa_xfer_type xfer_type = 0; /* shut up GCC */
+	size_t xfer_hdr_size, cnt, transfer_size;
+	struct wa_xfer_hdr *xfer_hdr0, *xfer_hdr;
+
+	d_fnstart(3, dev, "(xfer %p [rpipe %p] urb %p)\n",
+		  xfer, xfer->ep->hcpriv, urb);
+
+	result = __wa_xfer_setup_sizes(xfer, &xfer_type);
+	if (result < 0)
+		goto error_setup_sizes;
+	xfer_hdr_size = result;
+	result = __wa_xfer_setup_segs(xfer, xfer_hdr_size);
+	if (result < 0) {
+		dev_err(dev, "xfer %p: Failed to allocate %d segments: %d\n",
+			xfer, xfer->segs, result);
+		goto error_setup_segs;
+	}
+	/* Fill the first header */
+	xfer_hdr0 = &xfer->seg[0]->xfer_hdr;
+	wa_xfer_id_init(xfer);
+	__wa_xfer_setup_hdr0(xfer, xfer_hdr0, xfer_type, xfer_hdr_size);
+
+	/* Fill remainig headers */
+	xfer_hdr = xfer_hdr0;
+	transfer_size = urb->transfer_buffer_length;
+	xfer_hdr0->dwTransferLength = transfer_size > xfer->seg_size ?
+		xfer->seg_size : transfer_size;
+	transfer_size -=  xfer->seg_size;
+	for (cnt = 1; cnt < xfer->segs; cnt++) {
+		xfer_hdr = &xfer->seg[cnt]->xfer_hdr;
+		memcpy(xfer_hdr, xfer_hdr0, xfer_hdr_size);
+		xfer_hdr->bTransferSegment = cnt;
+		xfer_hdr->dwTransferLength = transfer_size > xfer->seg_size ?
+			cpu_to_le32(xfer->seg_size)
+			: cpu_to_le32(transfer_size);
+		xfer->seg[cnt]->status = WA_SEG_READY;
+		transfer_size -=  xfer->seg_size;
+	}
+	xfer_hdr->bTransferSegment |= 0x80;	/* this is the last segment */
+	result = 0;
+error_setup_segs:
+error_setup_sizes:
+	d_fnend(3, dev, "(xfer %p [rpipe %p] urb %p) = %d\n",
+		xfer, xfer->ep->hcpriv, urb, result);
+	return result;
+}
+
+/*
+ *
+ *
+ * rpipe->seg_lock is held!
+ */
+static int __wa_seg_submit(struct wa_rpipe *rpipe, struct wa_xfer *xfer,
+			   struct wa_seg *seg)
+{
+	int result;
+	result = usb_submit_urb(&seg->urb, GFP_ATOMIC);
+	if (result < 0) {
+		printk(KERN_ERR "xfer %p#%u: REQ submit failed: %d\n",
+		       xfer, seg->index, result);
+		goto error_seg_submit;
+	}
+	if (seg->dto_urb) {
+		result = usb_submit_urb(seg->dto_urb, GFP_ATOMIC);
+		if (result < 0) {
+			printk(KERN_ERR "xfer %p#%u: DTO submit failed: %d\n",
+			       xfer, seg->index, result);
+			goto error_dto_submit;
+		}
+	}
+	seg->status = WA_SEG_SUBMITTED;
+	rpipe_avail_dec(rpipe);
+	return 0;
+
+error_dto_submit:
+	usb_unlink_urb(&seg->urb);
+error_seg_submit:
+	seg->status = WA_SEG_ERROR;
+	seg->result = result;
+	return result;
+}
+
+/*
+ * Execute more queued request segments until the maximum concurrent allowed
+ *
+ * The ugly unlock/lock sequence on the error path is needed as the
+ * xfer->lock normally nests the seg_lock and not viceversa.
+ *
+ */
+static void wa_xfer_delayed_run(struct wa_rpipe *rpipe)
+{
+	int result;
+	struct device *dev = &rpipe->wa->usb_iface->dev;
+	struct wa_seg *seg;
+	struct wa_xfer *xfer;
+	unsigned long flags;
+
+	d_fnstart(1, dev, "(rpipe #%d) %d segments available\n",
+		  le16_to_cpu(rpipe->descr.wRPipeIndex),
+		  atomic_read(&rpipe->segs_available));
+	spin_lock_irqsave(&rpipe->seg_lock, flags);
+	while (atomic_read(&rpipe->segs_available) > 0
+	      && !list_empty(&rpipe->seg_list)) {
+		seg = list_entry(rpipe->seg_list.next, struct wa_seg,
+				 list_node);
+		list_del(&seg->list_node);
+		xfer = seg->xfer;
+		result = __wa_seg_submit(rpipe, xfer, seg);
+		d_printf(1, dev, "xfer %p#%u submitted from delayed "
+			 "[%d segments available] %d\n",
+			 xfer, seg->index,
+			 atomic_read(&rpipe->segs_available), result);
+		if (unlikely(result < 0)) {
+			spin_unlock_irqrestore(&rpipe->seg_lock, flags);
+			spin_lock_irqsave(&xfer->lock, flags);
+			__wa_xfer_abort(xfer);
+			xfer->segs_done++;
+			spin_unlock_irqrestore(&xfer->lock, flags);
+			spin_lock_irqsave(&rpipe->seg_lock, flags);
+		}
+	}
+	spin_unlock_irqrestore(&rpipe->seg_lock, flags);
+	d_fnend(1, dev, "(rpipe #%d) = void, %d segments available\n",
+		le16_to_cpu(rpipe->descr.wRPipeIndex),
+		atomic_read(&rpipe->segs_available));
+
+}
+
+/*
+ *
+ * xfer->lock is taken
+ *
+ * On failure submitting we just stop submitting and return error;
+ * wa_urb_enqueue_b() will execute the completion path
+ */
+static int __wa_xfer_submit(struct wa_xfer *xfer)
+{
+	int result;
+	struct wahc *wa = xfer->wa;
+	struct device *dev = &wa->usb_iface->dev;
+	unsigned cnt;
+	struct wa_seg *seg;
+	unsigned long flags;
+	struct wa_rpipe *rpipe = xfer->ep->hcpriv;
+	size_t maxrequests = le16_to_cpu(rpipe->descr.wRequests);
+	u8 available;
+	u8 empty;
+
+	d_fnstart(3, dev, "(xfer %p [rpipe %p])\n",
+		  xfer, xfer->ep->hcpriv);
+
+	spin_lock_irqsave(&wa->xfer_list_lock, flags);
+	list_add_tail(&xfer->list_node, &wa->xfer_list);
+	spin_unlock_irqrestore(&wa->xfer_list_lock, flags);
+
+	BUG_ON(atomic_read(&rpipe->segs_available) > maxrequests);
+	result = 0;
+	spin_lock_irqsave(&rpipe->seg_lock, flags);
+	for (cnt = 0; cnt < xfer->segs; cnt++) {
+		available = atomic_read(&rpipe->segs_available);
+		empty = list_empty(&rpipe->seg_list);
+		seg = xfer->seg[cnt];
+		d_printf(2, dev, "xfer %p#%u: available %u empty %u (%s)\n",
+			 xfer, cnt, available, empty,
+			 available == 0 || !empty ? "delayed" : "submitted");
+		if (available == 0 || !empty) {
+			d_printf(1, dev, "xfer %p#%u: delayed\n", xfer, cnt);
+			seg->status = WA_SEG_DELAYED;
+			list_add_tail(&seg->list_node, &rpipe->seg_list);
+		} else {
+			result = __wa_seg_submit(rpipe, xfer, seg);
+			if (result < 0)
+				goto error_seg_submit;
+		}
+		xfer->segs_submitted++;
+	}
+	spin_unlock_irqrestore(&rpipe->seg_lock, flags);
+	d_fnend(3, dev, "(xfer %p [rpipe %p]) = void\n", xfer,
+		xfer->ep->hcpriv);
+	return result;
+
+error_seg_submit:
+	__wa_xfer_abort(xfer);
+	spin_unlock_irqrestore(&rpipe->seg_lock, flags);
+	d_fnend(3, dev, "(xfer %p [rpipe %p]) = void\n", xfer,
+		xfer->ep->hcpriv);
+	return result;
+}
+
+/*
+ * Second part of a URB/transfer enqueuement
+ *
+ * Assumes this comes from wa_urb_enqueue() [maybe through
+ * wa_urb_enqueue_run()]. At this point:
+ *
+ * xfer->wa	filled and refcounted
+ * xfer->ep	filled with rpipe refcounted if
+ *              delayed == 0
+ * xfer->urb 	filled and refcounted (this is the case when called
+ *              from wa_urb_enqueue() as we come from usb_submit_urb()
+ *              and when called by wa_urb_enqueue_run(), as we took an
+ *              extra ref dropped by _run() after we return).
+ * xfer->gfp	filled
+ *
+ * If we fail at __wa_xfer_submit(), then we just check if we are done
+ * and if so, we run the completion procedure. However, if we are not
+ * yet done, we do nothing and wait for the completion handlers from
+ * the submitted URBs or from the xfer-result path to kick in. If xfer
+ * result never kicks in, the xfer will timeout from the USB code and
+ * dequeue() will be called.
+ */
+static void wa_urb_enqueue_b(struct wa_xfer *xfer)
+{
+	int result;
+	unsigned long flags;
+	struct urb *urb = xfer->urb;
+	struct wahc *wa = xfer->wa;
+	struct wusbhc *wusbhc = wa->wusb;
+	struct device *dev = &wa->usb_iface->dev;
+	struct wusb_dev *wusb_dev;
+	unsigned done;
+
+	d_fnstart(3, dev, "(wa %p urb %p)\n", wa, urb);
+	result = rpipe_get_by_ep(wa, xfer->ep, urb, xfer->gfp);
+	if (result < 0)
+		goto error_rpipe_get;
+	result = -ENODEV;
+	/* FIXME: segmentation broken -- kills DWA */
+	mutex_lock(&wusbhc->mutex);		/* get a WUSB dev */
+	if (urb->dev == NULL)
+		goto error_dev_gone;
+	wusb_dev = __wusb_dev_get_by_usb_dev(wusbhc, urb->dev);
+	if (wusb_dev == NULL) {
+		mutex_unlock(&wusbhc->mutex);
+		goto error_dev_gone;
+	}
+	mutex_unlock(&wusbhc->mutex);
+
+	spin_lock_irqsave(&xfer->lock, flags);
+	xfer->wusb_dev = wusb_dev;
+	result = urb->status;
+	if (urb->status != -EINPROGRESS)
+		goto error_dequeued;
+
+	result = __wa_xfer_setup(xfer, urb);
+	if (result < 0)
+		goto error_xfer_setup;
+	result = __wa_xfer_submit(xfer);
+	if (result < 0)
+		goto error_xfer_submit;
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	d_fnend(3, dev, "(wa %p urb %p) = void\n", wa, urb);
+	return;
+
+	/* this is basically wa_xfer_completion() broken up wa_xfer_giveback()
+	 * does a wa_xfer_put() that will call wa_xfer_destroy() and clean
+	 * upundo setup().
+	 */
+error_xfer_setup:
+error_dequeued:
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	/* FIXME: segmentation broken, kills DWA */
+	if (wusb_dev)
+		wusb_dev_put(wusb_dev);
+error_dev_gone:
+	rpipe_put(xfer->ep->hcpriv);
+error_rpipe_get:
+	xfer->result = result;
+	wa_xfer_giveback(xfer);
+	d_fnend(3, dev, "(wa %p urb %p) = (void) %d\n", wa, urb, result);
+	return;
+
+error_xfer_submit:
+	done = __wa_xfer_is_done(xfer);
+	xfer->result = result;
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	if (done)
+		wa_xfer_completion(xfer);
+	d_fnend(3, dev, "(wa %p urb %p) = (void) %d\n", wa, urb, result);
+	return;
+}
+
+/*
+ * Execute the delayed transfers in the Wire Adapter @wa
+ *
+ * We need to be careful here, as dequeue() could be called in the
+ * middle.  That's why we do the whole thing under the
+ * wa->xfer_list_lock. If dequeue() jumps in, it first locks urb->lock
+ * and then checks the list -- so as we would be acquiring in inverse
+ * order, we just drop the lock once we have the xfer and reacquire it
+ * later.
+ */
+void wa_urb_enqueue_run(struct work_struct *ws)
+{
+	struct wahc *wa = container_of(ws, struct wahc, xfer_work);
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_xfer *xfer, *next;
+	struct urb *urb;
+
+	d_fnstart(3, dev, "(wa %p)\n", wa);
+	spin_lock_irq(&wa->xfer_list_lock);
+	list_for_each_entry_safe(xfer, next, &wa->xfer_delayed_list,
+				 list_node) {
+		list_del_init(&xfer->list_node);
+		spin_unlock_irq(&wa->xfer_list_lock);
+
+		urb = xfer->urb;
+		wa_urb_enqueue_b(xfer);
+		usb_put_urb(urb);	/* taken when queuing */
+
+		spin_lock_irq(&wa->xfer_list_lock);
+	}
+	spin_unlock_irq(&wa->xfer_list_lock);
+	d_fnend(3, dev, "(wa %p) = void\n", wa);
+}
+EXPORT_SYMBOL_GPL(wa_urb_enqueue_run);
+
+/*
+ * Submit a transfer to the Wire Adapter in a delayed way
+ *
+ * The process of enqueuing involves possible sleeps() [see
+ * enqueue_b(), for the rpipe_get() and the mutex_lock()]. If we are
+ * in an atomic section, we defer the enqueue_b() call--else we call direct.
+ *
+ * @urb: We own a reference to it done by the HCI Linux USB stack that
+ *       will be given up by calling usb_hcd_giveback_urb() or by
+ *       returning error from this function -> ergo we don't have to
+ *       refcount it.
+ */
+int wa_urb_enqueue(struct wahc *wa, struct usb_host_endpoint *ep,
+		   struct urb *urb, gfp_t gfp)
+{
+	int result;
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_xfer *xfer;
+	unsigned long my_flags;
+	unsigned cant_sleep = irqs_disabled() | in_atomic();
+
+	d_fnstart(3, dev, "(wa %p ep %p urb %p [%d] gfp 0x%x)\n",
+		  wa, ep, urb, urb->transfer_buffer_length, gfp);
+
+	if (urb->transfer_buffer == NULL
+	    && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
+	    && urb->transfer_buffer_length != 0) {
+		dev_err(dev, "BUG? urb %p: NULL xfer buffer & NODMA\n", urb);
+		dump_stack();
+	}
+
+	result = -ENOMEM;
+	xfer = kzalloc(sizeof(*xfer), gfp);
+	if (xfer == NULL)
+		goto error_kmalloc;
+
+	result = -ENOENT;
+	if (urb->status != -EINPROGRESS)	/* cancelled */
+		goto error_dequeued;		/* before starting? */
+	wa_xfer_init(xfer);
+	xfer->wa = wa_get(wa);
+	xfer->urb = urb;
+	xfer->gfp = gfp;
+	xfer->ep = ep;
+	urb->hcpriv = xfer;
+	d_printf(2, dev, "xfer %p urb %p pipe 0x%02x [%d bytes] %s %s %s\n",
+		 xfer, urb, urb->pipe, urb->transfer_buffer_length,
+		 urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP ? "dma" : "nodma",
+		 urb->pipe & USB_DIR_IN ? "inbound" : "outbound",
+		 cant_sleep ? "deferred" : "inline");
+	if (cant_sleep) {
+		usb_get_urb(urb);
+		spin_lock_irqsave(&wa->xfer_list_lock, my_flags);
+		list_add_tail(&xfer->list_node, &wa->xfer_delayed_list);
+		spin_unlock_irqrestore(&wa->xfer_list_lock, my_flags);
+		queue_work(wusbd, &wa->xfer_work);
+	} else {
+		wa_urb_enqueue_b(xfer);
+	}
+	d_fnend(3, dev, "(wa %p ep %p urb %p [%d] gfp 0x%x) = 0\n",
+		wa, ep, urb, urb->transfer_buffer_length, gfp);
+	return 0;
+
+error_dequeued:
+	kfree(xfer);
+error_kmalloc:
+	d_fnend(3, dev, "(wa %p ep %p urb %p [%d] gfp 0x%x) = %d\n",
+		wa, ep, urb, urb->transfer_buffer_length, gfp, result);
+	return result;
+}
+EXPORT_SYMBOL_GPL(wa_urb_enqueue);
+
+/*
+ * Dequeue a URB and make sure uwb_hcd_giveback_urb() [completion
+ * handler] is called.
+ *
+ * Until a transfer goes successfully through wa_urb_enqueue() it
+ * needs to be dequeued with completion calling; when stuck in delayed
+ * or before wa_xfer_setup() is called, we need to do completion.
+ *
+ *  not setup  If there is no hcpriv yet, that means that that enqueue
+ *             still had no time to set the xfer up. Because
+ *             urb->status should be other than -EINPROGRESS,
+ *             enqueue() will catch that and bail out.
+ *
+ * If the transfer has gone through setup, we just need to clean it
+ * up. If it has gone through submit(), we have to abort it [with an
+ * asynch request] and then make sure we cancel each segment.
+ *
+ */
+int wa_urb_dequeue(struct wahc *wa, struct urb *urb)
+{
+	struct device *dev = &wa->usb_iface->dev;
+	unsigned long flags, flags2;
+	struct wa_xfer *xfer;
+	struct wa_seg *seg;
+	struct wa_rpipe *rpipe;
+	unsigned cnt;
+	unsigned rpipe_ready = 0;
+
+	d_fnstart(3, dev, "(wa %p, urb %p)\n", wa, urb);
+
+	d_printf(1, dev, "xfer %p urb %p: aborting\n", urb->hcpriv, urb);
+	xfer = urb->hcpriv;
+	if (xfer == NULL) {
+		/* NOthing setup yet enqueue will see urb->status !=
+		 * -EINPROGRESS (by hcd layer) and bail out with
+		 * error, no need to do completion
+		 */
+		BUG_ON(urb->status == -EINPROGRESS);
+		goto out;
+	}
+	spin_lock_irqsave(&xfer->lock, flags);
+	rpipe = xfer->ep->hcpriv;
+	/* Check the delayed list -> if there, release and complete */
+	spin_lock_irqsave(&wa->xfer_list_lock, flags2);
+	if (!list_empty(&xfer->list_node) && xfer->seg == NULL)
+		goto dequeue_delayed;
+	spin_unlock_irqrestore(&wa->xfer_list_lock, flags2);
+	if (xfer->seg == NULL)  	/* still hasn't reached */
+		goto out_unlock;	/* setup(), enqueue_b() completes */
+	/* Ok, the xfer is in flight already, it's been setup and submitted.*/
+	__wa_xfer_abort(xfer);
+	for (cnt = 0; cnt < xfer->segs; cnt++) {
+		seg = xfer->seg[cnt];
+		switch (seg->status) {
+		case WA_SEG_NOTREADY:
+		case WA_SEG_READY:
+			printk(KERN_ERR "xfer %p#%u: dequeue bad state %u\n",
+			       xfer, cnt, seg->status);
+			WARN_ON(1);
+			break;
+		case WA_SEG_DELAYED:
+			seg->status = WA_SEG_ABORTED;
+			spin_lock_irqsave(&rpipe->seg_lock, flags2);
+			list_del(&seg->list_node);
+			xfer->segs_done++;
+			rpipe_ready = rpipe_avail_inc(rpipe);
+			spin_unlock_irqrestore(&rpipe->seg_lock, flags2);
+			break;
+		case WA_SEG_SUBMITTED:
+			seg->status = WA_SEG_ABORTED;
+			usb_unlink_urb(&seg->urb);
+			if (xfer->is_inbound == 0)
+				usb_unlink_urb(seg->dto_urb);
+			xfer->segs_done++;
+			rpipe_ready = rpipe_avail_inc(rpipe);
+			break;
+		case WA_SEG_PENDING:
+			seg->status = WA_SEG_ABORTED;
+			xfer->segs_done++;
+			rpipe_ready = rpipe_avail_inc(rpipe);
+			break;
+		case WA_SEG_DTI_PENDING:
+			usb_unlink_urb(wa->dti_urb);
+			seg->status = WA_SEG_ABORTED;
+			xfer->segs_done++;
+			rpipe_ready = rpipe_avail_inc(rpipe);
+			break;
+		case WA_SEG_DONE:
+		case WA_SEG_ERROR:
+		case WA_SEG_ABORTED:
+			break;
+		}
+	}
+	xfer->result = urb->status;	/* -ENOENT or -ECONNRESET */
+	__wa_xfer_is_done(xfer);
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	wa_xfer_completion(xfer);
+	if (rpipe_ready)
+		wa_xfer_delayed_run(rpipe);
+	d_fnend(3, dev, "(wa %p, urb %p) = 0\n", wa, urb);
+	return 0;
+
+out_unlock:
+	spin_unlock_irqrestore(&xfer->lock, flags);
+out:
+	d_fnend(3, dev, "(wa %p, urb %p) = 0\n", wa, urb);
+	return 0;
+
+dequeue_delayed:
+	list_del_init(&xfer->list_node);
+	spin_unlock_irqrestore(&wa->xfer_list_lock, flags2);
+	xfer->result = urb->status;
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	wa_xfer_giveback(xfer);
+	usb_put_urb(urb);		/* we got a ref in enqueue() */
+	d_fnend(3, dev, "(wa %p, urb %p) = 0\n", wa, urb);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wa_urb_dequeue);
+
+/*
+ * Translation from WA status codes (WUSB1.0 Table 8.15) to errno
+ * codes
+ *
+ * Positive errno values are internal inconsistencies and should be
+ * flagged louder. Negative are to be passed up to the user in the
+ * normal way.
+ *
+ * @status: USB WA status code -- high two bits are stripped.
+ */
+static int wa_xfer_status_to_errno(u8 status)
+{
+	int errno;
+	u8 real_status = status;
+	static int xlat[] = {
+		[WA_XFER_STATUS_SUCCESS] = 		0,
+		[WA_XFER_STATUS_HALTED] = 		-EPIPE,
+		[WA_XFER_STATUS_DATA_BUFFER_ERROR] = 	-ENOBUFS,
+		[WA_XFER_STATUS_BABBLE] = 		-EOVERFLOW,
+		[WA_XFER_RESERVED] = 			EINVAL,
+		[WA_XFER_STATUS_NOT_FOUND] =		0,
+		[WA_XFER_STATUS_INSUFFICIENT_RESOURCE] = -ENOMEM,
+		[WA_XFER_STATUS_TRANSACTION_ERROR] = 	-EILSEQ,
+		[WA_XFER_STATUS_ABORTED] = 		-EINTR,
+		[WA_XFER_STATUS_RPIPE_NOT_READY] = 	EINVAL,
+		[WA_XFER_INVALID_FORMAT] = 		EINVAL,
+		[WA_XFER_UNEXPECTED_SEGMENT_NUMBER] = 	EINVAL,
+		[WA_XFER_STATUS_RPIPE_TYPE_MISMATCH] = 	EINVAL,
+	};
+	status &= 0x3f;
+
+	if (status == 0)
+		return 0;
+	if (status >= ARRAY_SIZE(xlat)) {
+		if (printk_ratelimit())
+			printk(KERN_ERR "%s(): BUG? "
+			       "Unknown WA transfer status 0x%02x\n",
+			       __func__, real_status);
+		return -EINVAL;
+	}
+	errno = xlat[status];
+	if (unlikely(errno > 0)) {
+		if (printk_ratelimit())
+			printk(KERN_ERR "%s(): BUG? "
+			       "Inconsistent WA status: 0x%02x\n",
+			       __func__, real_status);
+		errno = -errno;
+	}
+	return errno;
+}
+
+/*
+ * Process a xfer result completion message
+ *
+ * inbound transfers: need to schedule a DTI read
+ *
+ * FIXME: this functio needs to be broken up in parts
+ */
+static void wa_xfer_result_chew(struct wahc *wa, struct wa_xfer *xfer)
+{
+	int result;
+	struct device *dev = &wa->usb_iface->dev;
+	unsigned long flags;
+	u8 seg_idx;
+	struct wa_seg *seg;
+	struct wa_rpipe *rpipe;
+	struct wa_xfer_result *xfer_result = wa->xfer_result;
+	u8 done = 0;
+	u8 usb_status;
+	unsigned rpipe_ready = 0;
+
+	d_fnstart(3, dev, "(wa %p xfer %p)\n", wa, xfer);
+	spin_lock_irqsave(&xfer->lock, flags);
+	seg_idx = xfer_result->bTransferSegment & 0x7f;
+	if (unlikely(seg_idx >= xfer->segs))
+		goto error_bad_seg;
+	seg = xfer->seg[seg_idx];
+	rpipe = xfer->ep->hcpriv;
+	usb_status = xfer_result->bTransferStatus;
+	d_printf(2, dev, "xfer %p#%u: bTransferStatus 0x%02x (seg %u)\n",
+		 xfer, seg_idx, usb_status, seg->status);
+	if (seg->status == WA_SEG_ABORTED
+	    || seg->status == WA_SEG_ERROR)	/* already handled */
+		goto segment_aborted;
+	if (seg->status == WA_SEG_SUBMITTED)	/* ops, got here */
+		seg->status = WA_SEG_PENDING;	/* before wa_seg{_dto}_cb() */
+	if (seg->status != WA_SEG_PENDING) {
+		if (printk_ratelimit())
+			dev_err(dev, "xfer %p#%u: Bad segment state %u\n",
+				xfer, seg_idx, seg->status);
+		seg->status = WA_SEG_PENDING;	/* workaround/"fix" it */
+	}
+	if (usb_status & 0x80) {
+		seg->result = wa_xfer_status_to_errno(usb_status);
+		dev_err(dev, "DTI: xfer %p#%u failed (0x%02x)\n",
+			xfer, seg->index, usb_status);
+		goto error_complete;
+	}
+	/* FIXME: we ignore warnings, tally them for stats */
+	if (usb_status & 0x40) 		/* Warning?... */
+		usb_status = 0;		/* ... pass */
+	if (xfer->is_inbound) {	/* IN data phase: read to buffer */
+		seg->status = WA_SEG_DTI_PENDING;
+		BUG_ON(wa->buf_in_urb->status == -EINPROGRESS);
+		if (xfer->is_dma) {
+			wa->buf_in_urb->transfer_dma =
+				xfer->urb->transfer_dma
+				+ seg_idx * xfer->seg_size;
+			wa->buf_in_urb->transfer_flags
+				|= URB_NO_TRANSFER_DMA_MAP;
+		} else {
+			wa->buf_in_urb->transfer_buffer =
+				xfer->urb->transfer_buffer
+				+ seg_idx * xfer->seg_size;
+			wa->buf_in_urb->transfer_flags
+				&= ~URB_NO_TRANSFER_DMA_MAP;
+		}
+		wa->buf_in_urb->transfer_buffer_length =
+			le32_to_cpu(xfer_result->dwTransferLength);
+		wa->buf_in_urb->context = seg;
+		result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);
+		if (result < 0)
+			goto error_submit_buf_in;
+	} else {
+		/* OUT data phase, complete it -- */
+		seg->status = WA_SEG_DONE;
+		seg->result = le32_to_cpu(xfer_result->dwTransferLength);
+		xfer->segs_done++;
+		rpipe_ready = rpipe_avail_inc(rpipe);
+		done = __wa_xfer_is_done(xfer);
+	}
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	if (done)
+		wa_xfer_completion(xfer);
+	if (rpipe_ready)
+		wa_xfer_delayed_run(rpipe);
+	d_fnend(3, dev, "(wa %p xfer %p) = void\n", wa, xfer);
+	return;
+
+
+error_submit_buf_in:
+	if (edc_inc(&wa->dti_edc, EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
+		dev_err(dev, "DTI: URB max acceptable errors "
+			"exceeded, resetting device\n");
+		wa_reset_all(wa);
+	}
+	if (printk_ratelimit())
+		dev_err(dev, "xfer %p#%u: can't submit DTI data phase: %d\n",
+			xfer, seg_idx, result);
+	seg->result = result;
+error_complete:
+	seg->status = WA_SEG_ERROR;
+	xfer->segs_done++;
+	rpipe_ready = rpipe_avail_inc(rpipe);
+	__wa_xfer_abort(xfer);
+	done = __wa_xfer_is_done(xfer);
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	if (done)
+		wa_xfer_completion(xfer);
+	if (rpipe_ready)
+		wa_xfer_delayed_run(rpipe);
+	d_fnend(3, dev, "(wa %p xfer %p) = void [segment/DTI-submit error]\n",
+		wa, xfer);
+	return;
+
+
+error_bad_seg:
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	wa_urb_dequeue(wa, xfer->urb);
+	if (printk_ratelimit())
+		dev_err(dev, "xfer %p#%u: bad segment\n", xfer, seg_idx);
+	if (edc_inc(&wa->dti_edc, EDC_MAX_ERRORS, EDC_ERROR_TIMEFRAME)) {
+		dev_err(dev, "DTI: URB max acceptable errors "
+			"exceeded, resetting device\n");
+		wa_reset_all(wa);
+	}
+	d_fnend(3, dev, "(wa %p xfer %p) = void [bad seg]\n", wa, xfer);
+	return;
+
+
+segment_aborted:
+	/* nothing to do, as the aborter did the completion */
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	d_fnend(3, dev, "(wa %p xfer %p) = void [segment aborted]\n",
+		wa, xfer);
+	return;
+
+}
+
+/*
+ * Callback for the IN data phase
+ *
+ * If succesful transition state; otherwise, take a note of the
+ * error, mark this segment done and try completion.
+ *
+ * Note we don't access until we are sure that the transfer hasn't
+ * been cancelled (ECONNRESET, ENOENT), which could mean that
+ * seg->xfer could be already gone.
+ */
+static void wa_buf_in_cb(struct urb *urb)
+{
+	struct wa_seg *seg = urb->context;
+	struct wa_xfer *xfer = seg->xfer;
+	struct wahc *wa;
+	struct device *dev;
+	struct wa_rpipe *rpipe;
+	unsigned rpipe_ready;
+	unsigned long flags;
+	u8 done = 0;
+
+	d_fnstart(3, NULL, "(urb %p [%d])\n", urb, urb->status);
+	switch (urb->status) {
+	case 0:
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		rpipe = xfer->ep->hcpriv;
+		d_printf(2, dev, "xfer %p#%u: data in done (%zu bytes)\n",
+			   xfer, seg->index, (size_t)urb->actual_length);
+		seg->status = WA_SEG_DONE;
+		seg->result = urb->actual_length;
+		xfer->segs_done++;
+		rpipe_ready = rpipe_avail_inc(rpipe);
+		done = __wa_xfer_is_done(xfer);
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		if (done)
+			wa_xfer_completion(xfer);
+		if (rpipe_ready)
+			wa_xfer_delayed_run(rpipe);
+		break;
+	case -ECONNRESET:	/* URB unlinked; no need to do anything */
+	case -ENOENT:		/* as it was done by the who unlinked us */
+		break;
+	default:		/* Other errors ... */
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		rpipe = xfer->ep->hcpriv;
+		if (printk_ratelimit())
+			dev_err(dev, "xfer %p#%u: data in error %d\n",
+				xfer, seg->index, urb->status);
+		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)){
+			dev_err(dev, "DTO: URB max acceptable errors "
+				"exceeded, resetting device\n");
+			wa_reset_all(wa);
+		}
+		seg->status = WA_SEG_ERROR;
+		seg->result = urb->status;
+		xfer->segs_done++;
+		rpipe_ready = rpipe_avail_inc(rpipe);
+		__wa_xfer_abort(xfer);
+		done = __wa_xfer_is_done(xfer);
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		if (done)
+			wa_xfer_completion(xfer);
+		if (rpipe_ready)
+			wa_xfer_delayed_run(rpipe);
+	}
+	d_fnend(3, NULL, "(urb %p [%d]) = void\n", urb, urb->status);
+}
+
+/*
+ * Handle an incoming transfer result buffer
+ *
+ * Given a transfer result buffer, it completes the transfer (possibly
+ * scheduling and buffer in read) and then resubmits the DTI URB for a
+ * new transfer result read.
+ *
+ *
+ * The xfer_result DTI URB state machine
+ *
+ * States: OFF | RXR (Read-Xfer-Result) | RBI (Read-Buffer-In)
+ *
+ * We start in OFF mode, the first xfer_result notification [through
+ * wa_handle_notif_xfer()] moves us to RXR by posting the DTI-URB to
+ * read.
+ *
+ * We receive a buffer -- if it is not a xfer_result, we complain and
+ * repost the DTI-URB. If it is a xfer_result then do the xfer seg
+ * request accounting. If it is an IN segment, we move to RBI and post
+ * a BUF-IN-URB to the right buffer. The BUF-IN-URB callback will
+ * repost the DTI-URB and move to RXR state. if there was no IN
+ * segment, it will repost the DTI-URB.
+ *
+ * We go back to OFF when we detect a ENOENT or ESHUTDOWN (or too many
+ * errors) in the URBs.
+ */
+static void wa_xfer_result_cb(struct urb *urb)
+{
+	int result;
+	struct wahc *wa = urb->context;
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_xfer_result *xfer_result;
+	u32 xfer_id;
+	struct wa_xfer *xfer;
+	u8 usb_status;
+
+	d_fnstart(3, dev, "(%p)\n", wa);
+	BUG_ON(wa->dti_urb != urb);
+	switch (wa->dti_urb->status) {
+	case 0:
+		/* We have a xfer result buffer; check it */
+		d_printf(2, dev, "DTI: xfer result %d bytes at %p\n",
+			   urb->actual_length, urb->transfer_buffer);
+		d_dump(3, dev, urb->transfer_buffer, urb->actual_length);
+		if (wa->dti_urb->actual_length != sizeof(*xfer_result)) {
+			dev_err(dev, "DTI Error: xfer result--bad size "
+				"xfer result (%d bytes vs %zu needed)\n",
+				urb->actual_length, sizeof(*xfer_result));
+			break;
+		}
+		xfer_result = wa->xfer_result;
+		if (xfer_result->hdr.bLength != sizeof(*xfer_result)) {
+			dev_err(dev, "DTI Error: xfer result--"
+				"bad header length %u\n",
+				xfer_result->hdr.bLength);
+			break;
+		}
+		if (xfer_result->hdr.bNotifyType != WA_XFER_RESULT) {
+			dev_err(dev, "DTI Error: xfer result--"
+				"bad header type 0x%02x\n",
+				xfer_result->hdr.bNotifyType);
+			break;
+		}
+		usb_status = xfer_result->bTransferStatus & 0x3f;
+		if (usb_status == WA_XFER_STATUS_ABORTED
+		    || usb_status == WA_XFER_STATUS_NOT_FOUND)
+			/* taken care of already */
+			break;
+		xfer_id = xfer_result->dwTransferID;
+		xfer = wa_xfer_get_by_id(wa, xfer_id);
+		if (xfer == NULL) {
+			/* FIXME: transaction might have been cancelled */
+			dev_err(dev, "DTI Error: xfer result--"
+				"unknown xfer 0x%08x (status 0x%02x)\n",
+				xfer_id, usb_status);
+			break;
+		}
+		wa_xfer_result_chew(wa, xfer);
+		wa_xfer_put(xfer);
+		break;
+	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
+	case -ESHUTDOWN:	/* going away! */
+		dev_dbg(dev, "DTI: going down! %d\n", urb->status);
+		goto out;
+	default:
+		/* Unknown error */
+		if (edc_inc(&wa->dti_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)) {
+			dev_err(dev, "DTI: URB max acceptable errors "
+				"exceeded, resetting device\n");
+			wa_reset_all(wa);
+			goto out;
+		}
+		if (printk_ratelimit())
+			dev_err(dev, "DTI: URB error %d\n", urb->status);
+		break;
+	}
+	/* Resubmit the DTI URB */
+	result = usb_submit_urb(wa->dti_urb, GFP_ATOMIC);
+	if (result < 0) {
+		dev_err(dev, "DTI Error: Could not submit DTI URB (%d), "
+			"resetting\n", result);
+		wa_reset_all(wa);
+	}
+out:
+	d_fnend(3, dev, "(%p) = void\n", wa);
+	return;
+}
+
+/*
+ * Transfer complete notification
+ *
+ * Called from the notif.c code. We get a notification on EP2 saying
+ * that some endpoint has some transfer result data available. We are
+ * about to read it.
+ *
+ * To speed up things, we always have a URB reading the DTI URB; we
+ * don't really set it up and start it until the first xfer complete
+ * notification arrives, which is what we do here.
+ *
+ * Follow up in wa_xfer_result_cb(), as that's where the whole state
+ * machine starts.
+ *
+ * So here we just initialize the DTI URB for reading transfer result
+ * notifications and also the buffer-in URB, for reading buffers. Then
+ * we just submit the DTI URB.
+ *
+ * @wa shall be referenced
+ */
+void wa_handle_notif_xfer(struct wahc *wa, struct wa_notif_hdr *notif_hdr)
+{
+	int result;
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_notif_xfer *notif_xfer;
+	const struct usb_endpoint_descriptor *dti_epd = wa->dti_epd;
+
+	d_fnstart(4, dev, "(%p, %p)\n", wa, notif_hdr);
+	notif_xfer = container_of(notif_hdr, struct wa_notif_xfer, hdr);
+	BUG_ON(notif_hdr->bNotifyType != WA_NOTIF_TRANSFER);
+
+	if ((0x80 | notif_xfer->bEndpoint) != dti_epd->bEndpointAddress) {
+		/* FIXME: hardcoded limitation, adapt */
+		dev_err(dev, "BUG: DTI ep is %u, not %u (hack me)\n",
+			notif_xfer->bEndpoint, dti_epd->bEndpointAddress);
+		goto error;
+	}
+	if (wa->dti_urb != NULL)	/* DTI URB already started */
+		goto out;
+
+	wa->dti_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (wa->dti_urb == NULL) {
+		dev_err(dev, "Can't allocate DTI URB\n");
+		goto error_dti_urb_alloc;
+	}
+	usb_fill_bulk_urb(
+		wa->dti_urb, wa->usb_dev,
+		usb_rcvbulkpipe(wa->usb_dev, 0x80 | notif_xfer->bEndpoint),
+		wa->xfer_result, wa->xfer_result_size,
+		wa_xfer_result_cb, wa);
+
+	wa->buf_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (wa->buf_in_urb == NULL) {
+		dev_err(dev, "Can't allocate BUF-IN URB\n");
+		goto error_buf_in_urb_alloc;
+	}
+	usb_fill_bulk_urb(
+		wa->buf_in_urb, wa->usb_dev,
+		usb_rcvbulkpipe(wa->usb_dev, 0x80 | notif_xfer->bEndpoint),
+		NULL, 0, wa_buf_in_cb, wa);
+	result = usb_submit_urb(wa->dti_urb, GFP_KERNEL);
+	if (result < 0) {
+		dev_err(dev, "DTI Error: Could not submit DTI URB (%d), "
+			"resetting\n", result);
+		goto error_dti_urb_submit;
+	}
+out:
+	d_fnend(4, dev, "(%p, %p) = void\n", wa, notif_hdr);
+	return;
+
+error_dti_urb_submit:
+	usb_put_urb(wa->buf_in_urb);
+error_buf_in_urb_alloc:
+	usb_put_urb(wa->dti_urb);
+	wa->dti_urb = NULL;
+error_dti_urb_alloc:
+error:
+	wa_reset_all(wa);
+	d_fnend(4, dev, "(%p, %p) = void\n", wa, notif_hdr);
+	return;
+}