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 000000000000..7d192f3e6742
--- /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;
+}