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>

drivers/usb/wusbcore/Makefile

@@ -1,4 +1,5 @@
 obj-$(CONFIG_USB_WUSB)		+= wusbcore.o wusb-cbaf.o
+obj-$(CONFIG_USB_HWA_HCD)	+= wusb-wa.o
 
 wusbcore-objs := 	\
 	crypto.o	\
@@ -12,3 +13,8 @@ wusbcore-objs := 	\
 	wusbhc.o
 
 wusb-cbaf-objs := cbaf.o
+
+wusb-wa-objs :=	wa-hc.o		\
+		wa-nep.o	\
+		wa-rpipe.o	\
+		wa-xfer.o

drivers/usb/wusbcore/wa-hc.c

@@ -0,0 +1,95 @@
+/*
+ * Wire Adapter Host Controller Driver
+ * Common items to HWA and DWA based HCDs
+ *
+ * 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.
+ *
+ *
+ * FIXME: docs
+ */
+#include "wusbhc.h"
+#include "wa-hc.h"
+
+/**
+ * Assumes
+ *
+ * wa->usb_dev and wa->usb_iface initialized and refcounted,
+ * wa->wa_descr initialized.
+ */
+int wa_create(struct wahc *wa, struct usb_interface *iface)
+{
+	int result;
+	struct device *dev = &iface->dev;
+
+	result = wa_rpipes_create(wa);
+	if (result < 0)
+		goto error_rpipes_create;
+	/* Fill up Data Transfer EP pointers */
+	wa->dti_epd = &iface->cur_altsetting->endpoint[1].desc;
+	wa->dto_epd = &iface->cur_altsetting->endpoint[2].desc;
+	wa->xfer_result_size = le16_to_cpu(wa->dti_epd->wMaxPacketSize);
+	wa->xfer_result = kmalloc(wa->xfer_result_size, GFP_KERNEL);
+	if (wa->xfer_result == NULL)
+		goto error_xfer_result_alloc;
+	result = wa_nep_create(wa, iface);
+	if (result < 0) {
+		dev_err(dev, "WA-CDS: can't initialize notif endpoint: %d\n",
+			result);
+		goto error_nep_create;
+	}
+	return 0;
+
+error_nep_create:
+	kfree(wa->xfer_result);
+error_xfer_result_alloc:
+	wa_rpipes_destroy(wa);
+error_rpipes_create:
+	return result;
+}
+EXPORT_SYMBOL_GPL(wa_create);
+
+
+void __wa_destroy(struct wahc *wa)
+{
+	if (wa->dti_urb) {
+		usb_kill_urb(wa->dti_urb);
+		usb_put_urb(wa->dti_urb);
+		usb_kill_urb(wa->buf_in_urb);
+		usb_put_urb(wa->buf_in_urb);
+	}
+	kfree(wa->xfer_result);
+	wa_nep_destroy(wa);
+	wa_rpipes_destroy(wa);
+}
+EXPORT_SYMBOL_GPL(__wa_destroy);
+
+/**
+ * wa_reset_all - reset the WA device
+ * @wa: the WA to be reset
+ *
+ * For HWAs the radio controller and all other PALs are also reset.
+ */
+void wa_reset_all(struct wahc *wa)
+{
+	/* FIXME: assuming HWA. */
+	wusbhc_reset_all(wa->wusb);
+}
+
+MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
+MODULE_DESCRIPTION("Wireless USB Wire Adapter core");
+MODULE_LICENSE("GPL");

drivers/usb/wusbcore/wa-hc.h

@@ -0,0 +1,417 @@
+/*
+ * HWA Host Controller Driver
+ * Wire Adapter Control/Data Streaming Iface (WUSB1.0[8])
+ *
+ * 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.
+ *
+ *
+ * This driver implements a USB Host Controller (struct usb_hcd) for a
+ * Wireless USB Host Controller based on the Wireless USB 1.0
+ * Host-Wire-Adapter specification (in layman terms, a USB-dongle that
+ * implements a Wireless USB host).
+ *
+ * Check out the Design-overview.txt file in the source documentation
+ * for other details on the implementation.
+ *
+ * Main blocks:
+ *
+ *  driver     glue with the driver API, workqueue daemon
+ *
+ *  lc         RC instance life cycle management (create, destroy...)
+ *
+ *  hcd        glue with the USB API Host Controller Interface API.
+ *
+ *  nep        Notification EndPoint managent: collect notifications
+ *             and queue them with the workqueue daemon.
+ *
+ *             Handle notifications as coming from the NEP. Sends them
+ *             off others to their respective modules (eg: connect,
+ *             disconnect and reset go to devconnect).
+ *
+ *  rpipe      Remote Pipe management; rpipe is what we use to write
+ *             to an endpoint on a WUSB device that is connected to a
+ *             HWA RC.
+ *
+ *  xfer       Transfer managment -- this is all the code that gets a
+ *             buffer and pushes it to a device (or viceversa). *
+ *
+ * Some day a lot of this code will be shared between this driver and
+ * the drivers for DWA (xfer, rpipe).
+ *
+ * All starts at driver.c:hwahc_probe(), when one of this guys is
+ * connected. hwahc_disconnect() stops it.
+ *
+ * During operation, the main driver is devices connecting or
+ * disconnecting. They cause the HWA RC to send notifications into
+ * nep.c:hwahc_nep_cb() that will dispatch them to
+ * notif.c:wa_notif_dispatch(). From there they will fan to cause
+ * device connects, disconnects, etc.
+ *
+ * Note much of the activity is difficult to follow. For example a
+ * device connect goes to devconnect, which will cause the "fake" root
+ * hub port to show a connect and stop there. Then khubd will notice
+ * and call into the rh.c:hwahc_rc_port_reset() code to authenticate
+ * the device (and this might require user intervention) and enable
+ * the port.
+ *
+ * We also have a timer workqueue going from devconnect.c that
+ * schedules in hwahc_devconnect_create().
+ *
+ * The rest of the traffic is in the usual entry points of a USB HCD,
+ * which are hooked up in driver.c:hwahc_rc_driver, and defined in
+ * hcd.c.
+ */
+
+#ifndef __HWAHC_INTERNAL_H__
+#define __HWAHC_INTERNAL_H__
+
+#include <linux/completion.h>
+#include <linux/usb.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/uwb.h>
+#include <linux/usb/wusb.h>
+#include <linux/usb/wusb-wa.h>
+
+struct wusbhc;
+struct wahc;
+extern void wa_urb_enqueue_run(struct work_struct *ws);
+
+/**
+ * RPipe instance
+ *
+ * @descr's fields are kept in LE, as we need to send it back and
+ * forth.
+ *
+ * @wa is referenced when set
+ *
+ * @segs_available is the number of requests segments that still can
+ *                 be submitted to the controller without overloading
+ *                 it. It is initialized to descr->wRequests when
+ *                 aiming.
+ *
+ * A rpipe supports a max of descr->wRequests at the same time; before
+ * submitting seg_lock has to be taken. If segs_avail > 0, then we can
+ * submit; if not, we have to queue them.
+ */
+struct wa_rpipe {
+	struct kref refcnt;
+	struct usb_rpipe_descriptor descr;
+	struct usb_host_endpoint *ep;
+	struct wahc *wa;
+	spinlock_t seg_lock;
+	struct list_head seg_list;
+	atomic_t segs_available;
+	u8 buffer[1];	/* For reads/writes on USB */
+};
+
+
+/**
+ * Instance of a HWA Host Controller
+ *
+ * Except where a more specific lock/mutex applies or atomic, all
+ * fields protected by @mutex.
+ *
+ * @wa_descr  Can be accessed without locking because it is in
+ *            the same area where the device descriptors were
+ *            read, so it is guaranteed to exist umodified while
+ *            the device exists.
+ *
+ *            Endianess has been converted to CPU's.
+ *
+ * @nep_* can be accessed without locking as its processing is
+ *        serialized; we submit a NEP URB and it comes to
+ *        hwahc_nep_cb(), which won't issue another URB until it is
+ *        done processing it.
+ *
+ * @xfer_list:
+ *
+ *   List of active transfers to verify existence from a xfer id
+ *   gotten from the xfer result message. Can't use urb->list because
+ *   it goes by endpoint, and we don't know the endpoint at the time
+ *   when we get the xfer result message. We can't really rely on the
+ *   pointer (will have to change for 64 bits) as the xfer id is 32 bits.
+ *
+ * @xfer_delayed_list:   List of transfers that need to be started
+ *                       (with a workqueue, because they were
+ *                       submitted from an atomic context).
+ *
+ * FIXME: this needs to be layered up: a wusbhc layer (for sharing
+ *        comonalities with WHCI), a wa layer (for sharing
+ *        comonalities with DWA-RC).
+ */
+struct wahc {
+	struct usb_device *usb_dev;
+	struct usb_interface *usb_iface;
+
+	/* HC to deliver notifications */
+	union {
+		struct wusbhc *wusb;
+		struct dwahc *dwa;
+	};
+
+	const struct usb_endpoint_descriptor *dto_epd, *dti_epd;
+	const struct usb_wa_descriptor *wa_descr;
+
+	struct urb *nep_urb;		/* Notification EndPoint [lockless] */
+	struct edc nep_edc;
+	void *nep_buffer;
+	size_t nep_buffer_size;
+
+	atomic_t notifs_queued;
+
+	u16 rpipes;
+	unsigned long *rpipe_bm;	/* rpipe usage bitmap */
+	spinlock_t rpipe_bm_lock;	/* protect rpipe_bm */
+	struct mutex rpipe_mutex;	/* assigning resources to endpoints */
+
+	struct urb *dti_urb;		/* URB for reading xfer results */
+	struct urb *buf_in_urb;		/* URB for reading data in */
+	struct edc dti_edc;		/* DTI error density counter */
+	struct wa_xfer_result *xfer_result; /* real size = dti_ep maxpktsize */
+	size_t xfer_result_size;
+
+	s32 status;			/* For reading status */
+
+	struct list_head xfer_list;
+	struct list_head xfer_delayed_list;
+	spinlock_t xfer_list_lock;
+	struct work_struct xfer_work;
+	atomic_t xfer_id_count;
+};
+
+
+extern int wa_create(struct wahc *wa, struct usb_interface *iface);
+extern void __wa_destroy(struct wahc *wa);
+void wa_reset_all(struct wahc *wa);
+
+
+/* Miscellaneous constants */
+enum {
+	/** Max number of EPROTO errors we tolerate on the NEP in a
+	 * period of time */
+	HWAHC_EPROTO_MAX = 16,
+	/** Period of time for EPROTO errors (in jiffies) */
+	HWAHC_EPROTO_PERIOD = 4 * HZ,
+};
+
+
+/* Notification endpoint handling */
+extern int wa_nep_create(struct wahc *, struct usb_interface *);
+extern void wa_nep_destroy(struct wahc *);
+
+static inline int wa_nep_arm(struct wahc *wa, gfp_t gfp_mask)
+{
+	struct urb *urb = wa->nep_urb;
+	urb->transfer_buffer = wa->nep_buffer;
+	urb->transfer_buffer_length = wa->nep_buffer_size;
+	return usb_submit_urb(urb, gfp_mask);
+}
+
+static inline void wa_nep_disarm(struct wahc *wa)
+{
+	usb_kill_urb(wa->nep_urb);
+}
+
+
+/* RPipes */
+static inline void wa_rpipe_init(struct wahc *wa)
+{
+	spin_lock_init(&wa->rpipe_bm_lock);
+	mutex_init(&wa->rpipe_mutex);
+}
+
+static inline void wa_init(struct wahc *wa)
+{
+	edc_init(&wa->nep_edc);
+	atomic_set(&wa->notifs_queued, 0);
+	wa_rpipe_init(wa);
+	edc_init(&wa->dti_edc);
+	INIT_LIST_HEAD(&wa->xfer_list);
+	INIT_LIST_HEAD(&wa->xfer_delayed_list);
+	spin_lock_init(&wa->xfer_list_lock);
+	INIT_WORK(&wa->xfer_work, wa_urb_enqueue_run);
+	atomic_set(&wa->xfer_id_count, 1);
+}
+
+/**
+ * Destroy a pipe (when refcount drops to zero)
+ *
+ * Assumes it has been moved to the "QUIESCING" state.
+ */
+struct wa_xfer;
+extern void rpipe_destroy(struct kref *_rpipe);
+static inline
+void __rpipe_get(struct wa_rpipe *rpipe)
+{
+	kref_get(&rpipe->refcnt);
+}
+extern int rpipe_get_by_ep(struct wahc *, struct usb_host_endpoint *,
+			   struct urb *, gfp_t);
+static inline void rpipe_put(struct wa_rpipe *rpipe)
+{
+	kref_put(&rpipe->refcnt, rpipe_destroy);
+
+}
+extern void rpipe_ep_disable(struct wahc *, struct usb_host_endpoint *);
+extern int wa_rpipes_create(struct wahc *);
+extern void wa_rpipes_destroy(struct wahc *);
+static inline void rpipe_avail_dec(struct wa_rpipe *rpipe)
+{
+	atomic_dec(&rpipe->segs_available);
+}
+
+/**
+ * Returns true if the rpipe is ready to submit more segments.
+ */
+static inline int rpipe_avail_inc(struct wa_rpipe *rpipe)
+{
+	return atomic_inc_return(&rpipe->segs_available) > 0
+		&& !list_empty(&rpipe->seg_list);
+}
+
+
+/* Transferring data */
+extern int wa_urb_enqueue(struct wahc *, struct usb_host_endpoint *,
+			  struct urb *, gfp_t);
+extern int wa_urb_dequeue(struct wahc *, struct urb *);
+extern void wa_handle_notif_xfer(struct wahc *, struct wa_notif_hdr *);
+
+
+/* Misc
+ *
+ * FIXME: Refcounting for the actual @hwahc object is not correct; I
+ *        mean, this should be refcounting on the HCD underneath, but
+ *        it is not. In any case, the semantics for HCD refcounting
+ *        are *weird*...on refcount reaching zero it just frees
+ *        it...no RC specific function is called...unless I miss
+ *        something.
+ *
+ * FIXME: has to go away in favour of an 'struct' hcd based sollution
+ */
+static inline struct wahc *wa_get(struct wahc *wa)
+{
+	usb_get_intf(wa->usb_iface);
+	return wa;
+}
+
+static inline void wa_put(struct wahc *wa)
+{
+	usb_put_intf(wa->usb_iface);
+}
+
+
+static inline int __wa_feature(struct wahc *wa, unsigned op, u16 feature)
+{
+	return usb_control_msg(wa->usb_dev, usb_sndctrlpipe(wa->usb_dev, 0),
+			op ? USB_REQ_SET_FEATURE : USB_REQ_CLEAR_FEATURE,
+			USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			feature,
+			wa->usb_iface->cur_altsetting->desc.bInterfaceNumber,
+			NULL, 0, 1000 /* FIXME: arbitrary */);
+}
+
+
+static inline int __wa_set_feature(struct wahc *wa, u16 feature)
+{
+	return  __wa_feature(wa, 1, feature);
+}
+
+
+static inline int __wa_clear_feature(struct wahc *wa, u16 feature)
+{
+	return __wa_feature(wa, 0, feature);
+}
+
+
+/**
+ * Return the status of a Wire Adapter
+ *
+ * @wa:		Wire Adapter instance
+ * @returns     < 0 errno code on error, or status bitmap as described
+ *              in WUSB1.0[8.3.1.6].
+ *
+ * NOTE: need malloc, some arches don't take USB from the stack
+ */
+static inline
+s32 __wa_get_status(struct wahc *wa)
+{
+	s32 result;
+	result = usb_control_msg(
+		wa->usb_dev, usb_rcvctrlpipe(wa->usb_dev, 0),
+		USB_REQ_GET_STATUS,
+		USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+		0, wa->usb_iface->cur_altsetting->desc.bInterfaceNumber,
+		&wa->status, sizeof(wa->status),
+		1000 /* FIXME: arbitrary */);
+	if (result >= 0)
+		result = wa->status;
+	return result;
+}
+
+
+/**
+ * Waits until the Wire Adapter's status matches @mask/@value
+ *
+ * @wa:		Wire Adapter instance.
+ * @returns     < 0 errno code on error, otherwise status.
+ *
+ * Loop until the WAs status matches the mask and value (status & mask
+ * == value). Timeout if it doesn't happen.
+ *
+ * FIXME: is there an official specification on how long status
+ *        changes can take?
+ */
+static inline s32 __wa_wait_status(struct wahc *wa, u32 mask, u32 value)
+{
+	s32 result;
+	unsigned loops = 10;
+	do {
+		msleep(50);
+		result = __wa_get_status(wa);
+		if ((result & mask) == value)
+			break;
+		if (loops-- == 0) {
+			result = -ETIMEDOUT;
+			break;
+		}
+	} while (result >= 0);
+	return result;
+}
+
+
+/** Command @hwahc to stop, @returns 0 if ok, < 0 errno code on error */
+static inline int __wa_stop(struct wahc *wa)
+{
+	int result;
+	struct device *dev = &wa->usb_iface->dev;
+
+	result = __wa_clear_feature(wa, WA_ENABLE);
+	if (result < 0 && result != -ENODEV) {
+		dev_err(dev, "error commanding HC to stop: %d\n", result);
+		goto out;
+	}
+	result = __wa_wait_status(wa, WA_ENABLE, 0);
+	if (result < 0 && result != -ENODEV)
+		dev_err(dev, "error waiting for HC to stop: %d\n", result);
+out:
+	return 0;
+}
+
+
+#endif /* #ifndef __HWAHC_INTERNAL_H__ */

drivers/usb/wusbcore/wa-nep.c

@@ -0,0 +1,310 @@
+/*
+ * WUSB Wire Adapter: Control/Data Streaming Interface (WUSB[8])
+ * Notification EndPoint support
+ *
+ * Copyright (C) 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.
+ *
+ *
+ * This part takes care of getting the notification from the hw
+ * only and dispatching through wusbwad into
+ * wa_notif_dispatch. Handling is done there.
+ *
+ * WA notifications are limited in size; most of them are three or
+ * four bytes long, and the longest is the HWA Device Notification,
+ * which would not exceed 38 bytes (DNs are limited in payload to 32
+ * bytes plus 3 bytes header (WUSB1.0[7.6p2]), plus 3 bytes HWA
+ * header (WUSB1.0[8.5.4.2]).
+ *
+ * It is not clear if more than one Device Notification can be packed
+ * in a HWA Notification, I assume no because of the wording in
+ * WUSB1.0[8.5.4.2]. In any case, the bigger any notification could
+ * get is 256 bytes (as the bLength field is a byte).
+ *
+ * So what we do is we have this buffer and read into it; when a
+ * notification arrives we schedule work to a specific, single thread
+ * workqueue (so notifications are serialized) and copy the
+ * notification data. After scheduling the work, we rearm the read from
+ * the notification endpoint.
+ *
+ * Entry points here are:
+ *
+ * wa_nep_[create|destroy]()   To initialize/release this subsystem
+ *
+ * wa_nep_cb()                 Callback for the notification
+ *                                endpoint; when data is ready, this
+ *                                does the dispatching.
+ */
+#include <linux/workqueue.h>
+#include <linux/ctype.h>
+#include <linux/uwb/debug.h>
+#include "wa-hc.h"
+#include "wusbhc.h"
+
+/* Structure for queueing notifications to the workqueue */
+struct wa_notif_work {
+	struct work_struct work;
+	struct wahc *wa;
+	size_t size;
+	u8 data[];
+};
+
+/*
+ * Process incoming notifications from the WA's Notification EndPoint
+ * [the wuswad daemon, basically]
+ *
+ * @_nw:	Pointer to a descriptor which has the pointer to the
+ * 		@wa, the size of the buffer and the work queue
+ * 		structure (so we can free all when done).
+ * @returns     0 if ok, < 0 errno code on error.
+ *
+ * All notifications follow the same format; they need to start with a
+ * 'struct wa_notif_hdr' header, so it is easy to parse through
+ * them. We just break the buffer in individual notifications (the
+ * standard doesn't say if it can be done or is forbidden, so we are
+ * cautious) and dispatch each.
+ *
+ * So the handling layers are is:
+ *
+ *   WA specific notification (from NEP)
+ *      Device Notification Received -> wa_handle_notif_dn()
+ *        WUSB Device notification generic handling
+ *      BPST Adjustment -> wa_handle_notif_bpst_adj()
+ *      ... -> ...
+ *
+ * @wa has to be referenced
+ */
+static void wa_notif_dispatch(struct work_struct *ws)
+{
+	void *itr;
+	u8 missing = 0;
+	struct wa_notif_work *nw = container_of(ws, struct wa_notif_work, work);
+	struct wahc *wa = nw->wa;
+	struct wa_notif_hdr *notif_hdr;
+	size_t size;
+
+	struct device *dev = &wa->usb_iface->dev;
+
+#if 0
+	/* FIXME: need to check for this??? */
+	if (usb_hcd->state == HC_STATE_QUIESCING)	/* Going down? */
+		goto out;				/* screw it */
+#endif
+	atomic_dec(&wa->notifs_queued);		/* Throttling ctl */
+	dev = &wa->usb_iface->dev;
+	size = nw->size;
+	itr = nw->data;
+
+	while (size) {
+		if (size < sizeof(*notif_hdr)) {
+			missing = sizeof(*notif_hdr) - size;
+			goto exhausted_buffer;
+		}
+		notif_hdr = itr;
+		if (size < notif_hdr->bLength)
+			goto exhausted_buffer;
+		itr += notif_hdr->bLength;
+		size -= notif_hdr->bLength;
+		/* Dispatch the notification [don't use itr or size!] */
+		switch (notif_hdr->bNotifyType) {
+		case HWA_NOTIF_DN: {
+			struct hwa_notif_dn *hwa_dn;
+			hwa_dn = container_of(notif_hdr, struct hwa_notif_dn,
+					      hdr);
+			wusbhc_handle_dn(wa->wusb, hwa_dn->bSourceDeviceAddr,
+					 hwa_dn->dndata,
+					 notif_hdr->bLength - sizeof(*hwa_dn));
+			break;
+		}
+		case WA_NOTIF_TRANSFER:
+			wa_handle_notif_xfer(wa, notif_hdr);
+			break;
+		case DWA_NOTIF_RWAKE:
+		case DWA_NOTIF_PORTSTATUS:
+		case HWA_NOTIF_BPST_ADJ:
+			/* FIXME: unimplemented WA NOTIFs */
+			/* fallthru */
+		default:
+			if (printk_ratelimit()) {
+				dev_err(dev, "HWA: unknown notification 0x%x, "
+					"%zu bytes; discarding\n",
+					notif_hdr->bNotifyType,
+					(size_t)notif_hdr->bLength);
+				dump_bytes(dev, notif_hdr, 16);
+			}
+			break;
+		}
+	}
+out:
+	wa_put(wa);
+	kfree(nw);
+	return;
+
+	/* THIS SHOULD NOT HAPPEN
+	 *
+	 * Buffer exahusted with partial data remaining; just warn and
+	 * discard the data, as this should not happen.
+	 */
+exhausted_buffer:
+	if (!printk_ratelimit())
+		goto out;
+	dev_warn(dev, "HWA: device sent short notification, "
+		 "%d bytes missing; discarding %d bytes.\n",
+		 missing, (int)size);
+	dump_bytes(dev, itr, size);
+	goto out;
+}
+
+/*
+ * Deliver incoming WA notifications to the wusbwa workqueue
+ *
+ * @wa:	Pointer the Wire Adapter Controller Data Streaming
+ *              instance (part of an 'struct usb_hcd').
+ * @size:       Size of the received buffer
+ * @returns     0 if ok, < 0 errno code on error.
+ *
+ * The input buffer is @wa->nep_buffer, with @size bytes
+ * (guaranteed to fit in the allocated space,
+ * @wa->nep_buffer_size).
+ */
+static int wa_nep_queue(struct wahc *wa, size_t size)
+{
+	int result = 0;
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_notif_work *nw;
+
+	/* dev_fnstart(dev, "(wa %p, size %zu)\n", wa, size); */
+	BUG_ON(size > wa->nep_buffer_size);
+	if (size == 0)
+		goto out;
+	if (atomic_read(&wa->notifs_queued) > 200) {
+		if (printk_ratelimit())
+			dev_err(dev, "Too many notifications queued, "
+				"throttling back\n");
+		goto out;
+	}
+	nw = kzalloc(sizeof(*nw) + size, GFP_ATOMIC);
+	if (nw == NULL) {
+		if (printk_ratelimit())
+			dev_err(dev, "No memory to queue notification\n");
+		goto out;
+	}
+	INIT_WORK(&nw->work, wa_notif_dispatch);
+	nw->wa = wa_get(wa);
+	nw->size = size;
+	memcpy(nw->data, wa->nep_buffer, size);
+	atomic_inc(&wa->notifs_queued);		/* Throttling ctl */
+	queue_work(wusbd, &nw->work);
+out:
+	/* dev_fnend(dev, "(wa %p, size %zu) = result\n", wa, size, result); */
+	return result;
+}
+
+/*
+ * Callback for the notification event endpoint
+ *
+ * Check's that everything is fine and then passes the data to be
+ * queued to the workqueue.
+ */
+static void wa_nep_cb(struct urb *urb)
+{
+	int result;
+	struct wahc *wa = urb->context;
+	struct device *dev = &wa->usb_iface->dev;
+
+	switch (result = urb->status) {
+	case 0:
+		result = wa_nep_queue(wa, urb->actual_length);
+		if (result < 0)
+			dev_err(dev, "NEP: unable to process notification(s): "
+				"%d\n", result);
+		break;
+	case -ECONNRESET:	/* Not an error, but a controlled situation; */
+	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
+	case -ESHUTDOWN:
+		dev_dbg(dev, "NEP: going down %d\n", urb->status);
+		goto out;
+	default:	/* On general errors, we retry unless it gets ugly */
+		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)) {
+			dev_err(dev, "NEP: URB max acceptable errors "
+				"exceeded, resetting device\n");
+			wa_reset_all(wa);
+			goto out;
+		}
+		dev_err(dev, "NEP: URB error %d\n", urb->status);
+	}
+	result = wa_nep_arm(wa, GFP_ATOMIC);
+	if (result < 0) {
+		dev_err(dev, "NEP: cannot submit URB: %d\n", result);
+		wa_reset_all(wa);
+	}
+out:
+	return;
+}
+
+/*
+ * Initialize @wa's notification and event's endpoint stuff
+ *
+ * This includes the allocating the read buffer, the context ID
+ * allocation bitmap, the URB and submitting the URB.
+ */
+int wa_nep_create(struct wahc *wa, struct usb_interface *iface)
+{
+	int result;
+	struct usb_endpoint_descriptor *epd;
+	struct usb_device *usb_dev = interface_to_usbdev(iface);
+	struct device *dev = &iface->dev;
+
+	edc_init(&wa->nep_edc);
+	epd = &iface->cur_altsetting->endpoint[0].desc;
+	wa->nep_buffer_size = 1024;
+	wa->nep_buffer = kmalloc(wa->nep_buffer_size, GFP_KERNEL);
+	if (wa->nep_buffer == NULL) {
+		dev_err(dev, "Unable to allocate notification's read buffer\n");
+		goto error_nep_buffer;
+	}
+	wa->nep_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (wa->nep_urb == NULL) {
+		dev_err(dev, "Unable to allocate notification URB\n");
+		goto error_urb_alloc;
+	}
+	usb_fill_int_urb(wa->nep_urb, usb_dev,
+			 usb_rcvintpipe(usb_dev, epd->bEndpointAddress),
+			 wa->nep_buffer, wa->nep_buffer_size,
+			 wa_nep_cb, wa, epd->bInterval);
+	result = wa_nep_arm(wa, GFP_KERNEL);
+	if (result < 0) {
+		dev_err(dev, "Cannot submit notification URB: %d\n", result);
+		goto error_nep_arm;
+	}
+	return 0;
+
+error_nep_arm:
+	usb_free_urb(wa->nep_urb);
+error_urb_alloc:
+	kfree(wa->nep_buffer);
+error_nep_buffer:
+	return -ENOMEM;
+}
+
+void wa_nep_destroy(struct wahc *wa)
+{
+	wa_nep_disarm(wa);
+	usb_free_urb(wa->nep_urb);
+	kfree(wa->nep_buffer);
+}