uwb: add HWA radio controller driver

Add a driver for USB-connected UWB radio controllers (HWAs).

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

1 files changed, 911 insertions, 0 deletions

diff --git a/drivers/uwb/hwa-rc.c b/drivers/uwb/hwa-rc.c
new file mode 100644
index 0000000..f822a18
--- /dev/null
+++ b/drivers/uwb/hwa-rc.c
@@ -0,0 +1,911 @@
+/*
+ * WUSB Host Wire Adapter: Radio Control Interface (WUSB[8.6])
+ * Radio Control command/event transport
+ *
+ * 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.
+ *
+ *
+ * Initialize the Radio Control interface Driver.
+ *
+ * For each device probed, creates an 'struct hwarc' which contains
+ * just the representation of the UWB Radio Controller, and the logic
+ * for reading notifications and passing them to the UWB Core.
+ *
+ * So we initialize all of those, register the UWB Radio Controller
+ * and setup the notification/event handle to pipe the notifications
+ * to the UWB management Daemon.
+ *
+ * Command and event filtering.
+ *
+ * This is the driver for the Radio Control Interface described in WUSB
+ * 1.0. The core UWB module assumes that all drivers are compliant to the
+ * WHCI 0.95 specification. We thus create a filter that parses all
+ * incoming messages from the (WUSB 1.0) device and manipulate them to
+ * conform to the WHCI 0.95 specification. Similarly, outgoing messages
+ * are parsed and manipulated to conform to the WUSB 1.0 compliant messages
+ * that the device expects. Only a few messages are affected:
+ * Affected events:
+ *    UWB_RC_EVT_BEACON
+ *    UWB_RC_EVT_BP_SLOT_CHANGE
+ *    UWB_RC_EVT_DRP_AVAIL
+ *    UWB_RC_EVT_DRP
+ * Affected commands:
+ *    UWB_RC_CMD_SCAN
+ *    UWB_RC_CMD_SET_DRP_IE
+ *
+ *
+ *
+ */
+#include <linux/version.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/wusb.h>
+#include <linux/usb/wusb-wa.h>
+#include <linux/uwb.h>
+#include "uwb-internal.h"
+#define D_LOCAL 1
+#include <linux/uwb/debug.h>
+
+
+/**
+ * Descriptor for an instance of the UWB Radio Control Driver that
+ * attaches to the RCI interface of the Host Wired Adapter.
+ *
+ * Unless there is a lock specific to the 'data members', all access
+ * is protected by uwb_rc->mutex.
+ *
+ * The NEEP (Notification/Event EndPoint) URB (@neep_urb) writes to
+ * @rd_buffer. Note there is no locking because it is perfectly (heh!)
+ * serialized--probe() submits an URB, callback is called, processes
+ * the data (synchronously), submits another URB, and so on. There is
+ * no concurrent access to the buffer.
+ */
+struct hwarc {
+	struct usb_device *usb_dev;
+	struct usb_interface *usb_iface;
+	struct uwb_rc *uwb_rc;		/* UWB host controller */
+	struct urb *neep_urb;		/* Notification endpoint handling */
+	struct edc neep_edc;
+	void *rd_buffer;		/* NEEP read buffer */
+};
+
+
+/* Beacon received notification (WUSB 1.0 [8.6.3.2]) */
+struct uwb_rc_evt_beacon_WUSB_0100 {
+	struct uwb_rceb rceb;
+	u8	bChannelNumber;
+	__le16	wBPSTOffset;
+	u8	bLQI;
+	u8	bRSSI;
+	__le16	wBeaconInfoLength;
+	u8	BeaconInfo[];
+} __attribute__((packed));
+
+/**
+ * Filter WUSB 1.0 BEACON RCV notification to be WHCI 0.95
+ *
+ * @header: the incoming event
+ * @buf_size: size of buffer containing incoming event
+ * @new_size: size of event after filtering completed
+ *
+ * The WHCI 0.95 spec has a "Beacon Type" field. This value is unknown at
+ * the time we receive the beacon from WUSB so we just set it to
+ * UWB_RC_BEACON_TYPE_NEIGHBOR as a default.
+ * The solution below allocates memory upon receipt of every beacon from a
+ * WUSB device. This will deteriorate performance. What is the right way to
+ * do this?
+ */
+static
+int hwarc_filter_evt_beacon_WUSB_0100(struct uwb_rc *rc,
+				      struct uwb_rceb **header,
+				      const size_t buf_size,
+				      size_t *new_size)
+{
+	struct uwb_rc_evt_beacon_WUSB_0100 *be;
+	struct uwb_rc_evt_beacon *newbe;
+	size_t bytes_left, ielength;
+	struct device *dev = &rc->uwb_dev.dev;
+
+	be = container_of(*header, struct uwb_rc_evt_beacon_WUSB_0100, rceb);
+	bytes_left = buf_size;
+	if (bytes_left < sizeof(*be)) {
+		dev_err(dev, "Beacon Received Notification: Not enough data "
+			"to decode for filtering (%zu vs %zu bytes needed)\n",
+			bytes_left, sizeof(*be));
+		return -EINVAL;
+	}
+	bytes_left -= sizeof(*be);
+	ielength = le16_to_cpu(be->wBeaconInfoLength);
+	if (bytes_left < ielength) {
+		dev_err(dev, "Beacon Received Notification: Not enough data "
+			"to decode IEs (%zu vs %zu bytes needed)\n",
+			bytes_left, ielength);
+		return -EINVAL;
+	}
+	newbe = kzalloc(sizeof(*newbe) + ielength, GFP_ATOMIC);
+	if (newbe == NULL)
+		return -ENOMEM;
+	newbe->rceb = be->rceb;
+	newbe->bChannelNumber = be->bChannelNumber;
+	newbe->bBeaconType = UWB_RC_BEACON_TYPE_NEIGHBOR;
+	newbe->wBPSTOffset = be->wBPSTOffset;
+	newbe->bLQI = be->bLQI;
+	newbe->bRSSI = be->bRSSI;
+	newbe->wBeaconInfoLength = be->wBeaconInfoLength;
+	memcpy(newbe->BeaconInfo, be->BeaconInfo, ielength);
+	*header = &newbe->rceb;
+	*new_size = sizeof(*newbe) + ielength;
+	return 1;  /* calling function will free memory */
+}
+
+
+/* DRP Availability change notification (WUSB 1.0 [8.6.3.8]) */
+struct uwb_rc_evt_drp_avail_WUSB_0100 {
+	struct uwb_rceb rceb;
+	__le16 wIELength;
+	u8 IEData[];
+} __attribute__((packed));
+
+/**
+ * Filter WUSB 1.0 DRP AVAILABILITY CHANGE notification to be WHCI 0.95
+ *
+ * @header: the incoming event
+ * @buf_size: size of buffer containing incoming event
+ * @new_size: size of event after filtering completed
+ */
+static
+int hwarc_filter_evt_drp_avail_WUSB_0100(struct uwb_rc *rc,
+					 struct uwb_rceb **header,
+					 const size_t buf_size,
+					 size_t *new_size)
+{
+	struct uwb_rc_evt_drp_avail_WUSB_0100 *da;
+	struct uwb_rc_evt_drp_avail *newda;
+	struct uwb_ie_hdr *ie_hdr;
+	size_t bytes_left, ielength;
+	struct device *dev = &rc->uwb_dev.dev;
+
+
+	da = container_of(*header, struct uwb_rc_evt_drp_avail_WUSB_0100, rceb);
+	bytes_left = buf_size;
+	if (bytes_left < sizeof(*da)) {
+		dev_err(dev, "Not enough data to decode DRP Avail "
+			"Notification for filtering. Expected %zu, "
+			"received %zu.\n", (size_t)sizeof(*da), bytes_left);
+		return -EINVAL;
+	}
+	bytes_left -= sizeof(*da);
+	ielength = le16_to_cpu(da->wIELength);
+	if (bytes_left < ielength) {
+		dev_err(dev, "DRP Avail Notification filter: IE length "
+			"[%zu bytes] does not match actual length "
+			"[%zu bytes].\n", ielength, bytes_left);
+		return -EINVAL;
+	}
+	if (ielength < sizeof(*ie_hdr)) {
+		dev_err(dev, "DRP Avail Notification filter: Not enough "
+			"data to decode IE [%zu bytes, %zu needed]\n",
+			ielength, sizeof(*ie_hdr));
+		return -EINVAL;
+	}
+	ie_hdr = (void *) da->IEData;
+	if (ie_hdr->length > 32) {
+		dev_err(dev, "DRP Availability Change event has unexpected "
+			"length for filtering. Expected < 32 bytes, "
+			"got %zu bytes.\n", (size_t)ie_hdr->length);
+		return -EINVAL;
+	}
+	newda = kzalloc(sizeof(*newda), GFP_ATOMIC);
+	if (newda == NULL)
+		return -ENOMEM;
+	newda->rceb = da->rceb;
+	memcpy(newda->bmp, (u8 *) ie_hdr + sizeof(*ie_hdr), ie_hdr->length);
+	*header = &newda->rceb;
+	*new_size = sizeof(*newda);
+	return 1; /* calling function will free memory */
+}
+
+
+/* DRP notification (WUSB 1.0 [8.6.3.9]) */
+struct uwb_rc_evt_drp_WUSB_0100 {
+	struct uwb_rceb rceb;
+	struct uwb_dev_addr wSrcAddr;
+	u8 bExplicit;
+	__le16 wIELength;
+	u8 IEData[];
+} __attribute__((packed));
+
+/**
+ * Filter WUSB 1.0 DRP Notification to be WHCI 0.95
+ *
+ * @header: the incoming event
+ * @buf_size: size of buffer containing incoming event
+ * @new_size: size of event after filtering completed
+ *
+ * It is hard to manage DRP reservations without having a Reason code.
+ * Unfortunately there is none in the WUSB spec. We just set the default to
+ * DRP IE RECEIVED.
+ * We do not currently use the bBeaconSlotNumber value, so we set this to
+ * zero for now.
+ */
+static
+int hwarc_filter_evt_drp_WUSB_0100(struct uwb_rc *rc,
+				   struct uwb_rceb **header,
+				   const size_t buf_size,
+				   size_t *new_size)
+{
+	struct uwb_rc_evt_drp_WUSB_0100 *drpev;
+	struct uwb_rc_evt_drp *newdrpev;
+	size_t bytes_left, ielength;
+	struct device *dev = &rc->uwb_dev.dev;
+
+	drpev = container_of(*header, struct uwb_rc_evt_drp_WUSB_0100, rceb);
+	bytes_left = buf_size;
+	if (bytes_left < sizeof(*drpev)) {
+		dev_err(dev, "Not enough data to decode DRP Notification "
+			"for filtering. Expected %zu, received %zu.\n",
+			(size_t)sizeof(*drpev), bytes_left);
+		return -EINVAL;
+	}
+	ielength = le16_to_cpu(drpev->wIELength);
+	bytes_left -= sizeof(*drpev);
+	if (bytes_left < ielength) {
+		dev_err(dev, "DRP Notification filter: header length [%zu "
+			"bytes] does not match actual length [%zu "
+			"bytes].\n", ielength, bytes_left);
+		return -EINVAL;
+	}
+	newdrpev = kzalloc(sizeof(*newdrpev) + ielength, GFP_ATOMIC);
+	if (newdrpev == NULL)
+		return -ENOMEM;
+	newdrpev->rceb = drpev->rceb;
+	newdrpev->src_addr = drpev->wSrcAddr;
+	newdrpev->reason = UWB_DRP_NOTIF_DRP_IE_RCVD;
+	newdrpev->beacon_slot_number = 0;
+	newdrpev->ie_length = drpev->wIELength;
+	memcpy(newdrpev->ie_data, drpev->IEData, ielength);
+	*header = &newdrpev->rceb;
+	*new_size = sizeof(*newdrpev) + ielength;
+	return 1; /* calling function will free memory */
+}
+
+
+/* Scan Command (WUSB 1.0 [8.6.2.5]) */
+struct uwb_rc_cmd_scan_WUSB_0100 {
+	struct uwb_rccb rccb;
+	u8 bChannelNumber;
+	u8 bScanState;
+} __attribute__((packed));
+
+/**
+ * Filter WHCI 0.95 SCAN command to be WUSB 1.0 SCAN command
+ *
+ * @header:   command sent to device (compliant to WHCI 0.95)
+ * @size:     size of command sent to device
+ *
+ * We only reduce the size by two bytes because the WUSB 1.0 scan command
+ * does not have the last field (wStarttime). Also, make sure we don't send
+ * the device an unexpected scan type.
+ */
+static
+int hwarc_filter_cmd_scan_WUSB_0100(struct uwb_rc *rc,
+				    struct uwb_rccb **header,
+				    size_t *size)
+{
+	struct uwb_rc_cmd_scan *sc;
+
+	sc = container_of(*header, struct uwb_rc_cmd_scan, rccb);
+
+	if (sc->bScanState == UWB_SCAN_ONLY_STARTTIME)
+		sc->bScanState = UWB_SCAN_ONLY;
+	/* Don't send the last two bytes. */
+	*size -= 2;
+	return 0;
+}
+
+
+/* SET DRP IE command (WUSB 1.0 [8.6.2.7]) */
+struct uwb_rc_cmd_set_drp_ie_WUSB_0100 {
+	struct uwb_rccb rccb;
+	u8 bExplicit;
+	__le16 wIELength;
+	struct uwb_ie_drp IEData[];
+} __attribute__((packed));
+
+/**
+ * Filter WHCI 0.95 SET DRP IE command to be WUSB 1.0 SET DRP IE command
+ *
+ * @header:   command sent to device (compliant to WHCI 0.95)
+ * @size:     size of command sent to device
+ *
+ * WUSB has an extra bExplicit field - we assume always explicit
+ * negotiation so this field is set. The command expected by the device is
+ * thus larger than the one prepared by the driver so we need to
+ * reallocate memory to accommodate this.
+ * We trust the driver to send us the correct data so no checking is done
+ * on incoming data - evn though it is variable length.
+ */
+static
+int hwarc_filter_cmd_set_drp_ie_WUSB_0100(struct uwb_rc *rc,
+					  struct uwb_rccb **header,
+					  size_t *size)
+{
+	struct uwb_rc_cmd_set_drp_ie *orgcmd;
+	struct uwb_rc_cmd_set_drp_ie_WUSB_0100 *cmd;
+	size_t ielength;
+
+	orgcmd = container_of(*header, struct uwb_rc_cmd_set_drp_ie, rccb);
+	ielength = le16_to_cpu(orgcmd->wIELength);
+	cmd = kzalloc(sizeof(*cmd) + ielength, GFP_KERNEL);
+	if (cmd == NULL)
+		return -ENOMEM;
+	cmd->rccb = orgcmd->rccb;
+	cmd->bExplicit = 0;
+	cmd->wIELength = orgcmd->wIELength;
+	memcpy(cmd->IEData, orgcmd->IEData, ielength);
+	*header = &cmd->rccb;
+	*size = sizeof(*cmd) + ielength;
+	return 1; /* calling function will free memory */
+}
+
+
+/**
+ * Filter data from WHCI driver to WUSB device
+ *
+ * @header: WHCI 0.95 compliant command from driver
+ * @size:   length of command
+ *
+ * The routine managing commands to the device (uwb_rc_cmd()) will call the
+ * filtering function pointer (if it exists) before it passes any data to
+ * the device. At this time the command has been formatted according to
+ * WHCI 0.95 and is ready to be sent to the device.
+ *
+ * The filter function will be provided with the current command and its
+ * length. The function will manipulate the command if necessary and
+ * potentially reallocate memory for a command that needed more memory that
+ * the given command. If new memory was created the function will return 1
+ * to indicate to the calling function that the memory need to be freed
+ * when not needed any more. The size will contain the new length of the
+ * command.
+ * If memory has not been allocated we rely on the original mechanisms to
+ * free the memory of the command - even when we reduce the value of size.
+ */
+static
+int hwarc_filter_cmd_WUSB_0100(struct uwb_rc *rc, struct uwb_rccb **header,
+			       size_t *size)
+{
+	int result;
+	struct uwb_rccb *rccb = *header;
+	int cmd = le16_to_cpu(rccb->wCommand);
+	switch (cmd) {
+	case UWB_RC_CMD_SCAN:
+		result = hwarc_filter_cmd_scan_WUSB_0100(rc, header, size);
+		break;
+	case UWB_RC_CMD_SET_DRP_IE:
+		result = hwarc_filter_cmd_set_drp_ie_WUSB_0100(rc, header, size);
+		break;
+	default:
+		result = -ENOANO;
+		break;
+	}
+	return result;
+}
+
+
+/**
+ * Filter data from WHCI driver to WUSB device
+ *
+ * @header: WHCI 0.95 compliant command from driver
+ * @size:   length of command
+ *
+ * Filter commands based on which protocol the device supports. The WUSB
+ * errata should be the same as WHCI 0.95 so we do not filter that here -
+ * only WUSB 1.0.
+ */
+static
+int hwarc_filter_cmd(struct uwb_rc *rc, struct uwb_rccb **header,
+		     size_t *size)
+{
+	int result = -ENOANO;
+	if (rc->version == 0x0100)
+		result = hwarc_filter_cmd_WUSB_0100(rc, header, size);
+	return result;
+}
+
+
+/**
+ * Compute return value as sum of incoming value and value at given offset
+ *
+ * @rceb:      event for which we compute the size, it contains a variable
+ *	       length field.
+ * @core_size: size of the "non variable" part of the event
+ * @offset:    place in event where the length of the variable part is stored
+ * @buf_size: total length of buffer in which event arrived - we need to make
+ *	       sure we read the offset in memory that is still part of the event
+ */
+static
+ssize_t hwarc_get_event_size(struct uwb_rc *rc, const struct uwb_rceb *rceb,
+			     size_t core_size, size_t offset,
+			     const size_t buf_size)
+{
+	ssize_t size = -ENOSPC;
+	const void *ptr = rceb;
+	size_t type_size = sizeof(__le16);
+	struct device *dev = &rc->uwb_dev.dev;
+
+	if (offset + type_size >= buf_size) {
+		dev_err(dev, "Not enough data to read extra size of event "
+			"0x%02x/%04x/%02x, only got %zu bytes.\n",
+			rceb->bEventType, le16_to_cpu(rceb->wEvent),
+			rceb->bEventContext, buf_size);
+		goto out;
+	}
+	ptr += offset;
+	size = core_size + le16_to_cpu(*(__le16 *)ptr);
+out:
+	return size;
+}
+
+
+/* Beacon slot change notification (WUSB 1.0 [8.6.3.5]) */
+struct uwb_rc_evt_bp_slot_change_WUSB_0100 {
+	struct uwb_rceb rceb;
+	u8 bSlotNumber;
+} __attribute__((packed));
+
+
+/**
+ * Filter data from WUSB device to WHCI driver
+ *
+ * @header:	 incoming event
+ * @buf_size:	 size of buffer in which event arrived
+ * @_event_size: actual size of event in the buffer
+ * @new_size:	 size of event after filtered
+ *
+ * We don't know how the buffer is constructed - there may be more than one
+ * event in it so buffer length does not determine event length. We first
+ * determine the expected size of the incoming event. This value is passed
+ * back only if the actual filtering succeeded (so we know the computed
+ * expected size is correct). This value will be zero if
+ * the event did not need any filtering.
+ *
+ * WHCI interprets the BP Slot Change event's data differently than
+ * WUSB. The event sizes are exactly the same. The data field
+ * indicates the new beacon slot in which a RC is transmitting its
+ * beacon. The maximum value of this is 96 (wMacBPLength ECMA-368
+ * 17.16 (Table 117)). We thus know that the WUSB value will not set
+ * the bit bNoSlot, so we don't really do anything (placeholder).
+ */
+static
+int hwarc_filter_event_WUSB_0100(struct uwb_rc *rc, struct uwb_rceb **header,
+				 const size_t buf_size, size_t *_real_size,
+				 size_t *_new_size)
+{
+	int result = -ENOANO;
+	struct uwb_rceb *rceb = *header;
+	int event = le16_to_cpu(rceb->wEvent);
+	size_t event_size;
+	size_t core_size, offset;
+
+	if (rceb->bEventType != UWB_RC_CET_GENERAL)
+		goto out;
+	switch (event) {
+	case UWB_RC_EVT_BEACON:
+		core_size = sizeof(struct uwb_rc_evt_beacon_WUSB_0100);
+		offset = offsetof(struct uwb_rc_evt_beacon_WUSB_0100,
+				  wBeaconInfoLength);
+		event_size = hwarc_get_event_size(rc, rceb, core_size,
+						  offset, buf_size);
+		if (event_size < 0)
+			goto out;
+		*_real_size = event_size;
+		result = hwarc_filter_evt_beacon_WUSB_0100(rc, header,
+							   buf_size, _new_size);
+		break;
+	case UWB_RC_EVT_BP_SLOT_CHANGE:
+		*_new_size = *_real_size =
+			sizeof(struct uwb_rc_evt_bp_slot_change_WUSB_0100);
+		result = 0;
+		break;
+
+	case UWB_RC_EVT_DRP_AVAIL:
+		core_size = sizeof(struct uwb_rc_evt_drp_avail_WUSB_0100);
+		offset = offsetof(struct uwb_rc_evt_drp_avail_WUSB_0100,
+				  wIELength);
+		event_size = hwarc_get_event_size(rc, rceb, core_size,
+						  offset, buf_size);
+		if (event_size < 0)
+			goto out;
+		*_real_size = event_size;
+		result = hwarc_filter_evt_drp_avail_WUSB_0100(
+			rc, header, buf_size, _new_size);
+		break;
+
+	case UWB_RC_EVT_DRP:
+		core_size = sizeof(struct uwb_rc_evt_drp_WUSB_0100);
+		offset = offsetof(struct uwb_rc_evt_drp_WUSB_0100, wIELength);
+		event_size = hwarc_get_event_size(rc, rceb, core_size,
+						  offset, buf_size);
+		if (event_size < 0)
+			goto out;
+		*_real_size = event_size;
+		result = hwarc_filter_evt_drp_WUSB_0100(rc, header,
+							buf_size, _new_size);
+		break;
+
+	default:
+		break;
+	}
+out:
+	return result;
+}
+
+/**
+ * Filter data from WUSB device to WHCI driver
+ *
+ * @header:	 incoming event
+ * @buf_size:	 size of buffer in which event arrived
+ * @_event_size: actual size of event in the buffer
+ * @_new_size:	 size of event after filtered
+ *
+ * Filter events based on which protocol the device supports. The WUSB
+ * errata should be the same as WHCI 0.95 so we do not filter that here -
+ * only WUSB 1.0.
+ *
+ * If we don't handle it, we return -ENOANO (why the weird error code?
+ * well, so if I get it, I can pinpoint in the code that raised
+ * it...after all, not too many places use the higher error codes).
+ */
+static
+int hwarc_filter_event(struct uwb_rc *rc, struct uwb_rceb **header,
+		       const size_t buf_size, size_t *_real_size,
+		       size_t *_new_size)
+{
+	int result = -ENOANO;
+	if (rc->version == 0x0100)
+		result =  hwarc_filter_event_WUSB_0100(
+			rc, header, buf_size, _real_size, _new_size);
+	return result;
+}
+
+
+/**
+ * Execute an UWB RC command on HWA
+ *
+ * @rc:	      Instance of a Radio Controller that is a HWA
+ * @cmd:      Buffer containing the RCCB and payload to execute
+ * @cmd_size: Size of the command buffer.
+ *
+ * NOTE: rc's mutex has to be locked
+ */
+static
+int hwarc_cmd(struct uwb_rc *uwb_rc, const struct uwb_rccb *cmd, size_t cmd_size)
+{
+	struct hwarc *hwarc = uwb_rc->priv;
+	return usb_control_msg(
+		hwarc->usb_dev, usb_sndctrlpipe(hwarc->usb_dev, 0),
+		WA_EXEC_RC_CMD, USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+		0, hwarc->usb_iface->cur_altsetting->desc.bInterfaceNumber,
+		(void *) cmd, cmd_size, 100 /* FIXME: this is totally arbitrary */);
+}
+
+static
+int hwarc_reset(struct uwb_rc *uwb_rc)
+{
+	struct hwarc *hwarc = uwb_rc->priv;
+	return usb_reset_device(hwarc->usb_dev);
+}
+
+/**
+ * Callback for the notification and event endpoint
+ *
+ * Check's that everything is fine and then passes the read data to
+ * the notification/event handling mechanism (neh).
+ */
+static
+void hwarc_neep_cb(struct urb *urb)
+{
+	struct hwarc *hwarc = urb->context;
+	struct usb_interface *usb_iface = hwarc->usb_iface;
+	struct device *dev = &usb_iface->dev;
+	int result;
+
+	switch (result = urb->status) {
+	case 0:
+		d_printf(3, dev, "NEEP: receive stat %d, %zu bytes\n",
+			 urb->status, (size_t)urb->actual_length);
+		uwb_rc_neh_grok(hwarc->uwb_rc, urb->transfer_buffer,
+				urb->actual_length);
+		break;
+	case -ECONNRESET:	/* Not an error, but a controlled situation; */
+	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
+		d_printf(2, dev, "NEEP: URB reset/noent %d\n", urb->status);
+		goto out;
+	case -ESHUTDOWN:	/* going away! */
+		d_printf(2, dev, "NEEP: URB down %d\n", urb->status);
+		goto out;
+	default:		/* On general errors, retry unless it gets ugly */
+		if (edc_inc(&hwarc->neep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME))
+			goto error_exceeded;
+		dev_err(dev, "NEEP: URB error %d\n", urb->status);
+	}
+	result = usb_submit_urb(urb, GFP_ATOMIC);
+	d_printf(3, dev, "NEEP: submit %d\n", result);
+	if (result < 0) {
+		dev_err(dev, "NEEP: Can't resubmit URB (%d) resetting device\n",
+			result);
+		goto error;
+	}
+out:
+	return;
+
+error_exceeded:
+	dev_err(dev, "NEEP: URB max acceptable errors "
+		"exceeded, resetting device\n");
+error:
+	uwb_rc_neh_error(hwarc->uwb_rc, result);
+	uwb_rc_reset_all(hwarc->uwb_rc);
+	return;
+}
+
+static void hwarc_init(struct hwarc *hwarc)
+{
+	edc_init(&hwarc->neep_edc);
+}
+
+/**
+ * Initialize the notification/event endpoint stuff
+ *
+ * Note this is effectively a parallel thread; it knows that
+ * hwarc->uwb_rc always exists because the existence of a 'hwarc'
+ * means that there is a reverence on the hwarc->uwb_rc (see
+ * _probe()), and thus _neep_cb() can execute safely.
+ */
+static int hwarc_neep_init(struct uwb_rc *rc)
+{
+	struct hwarc *hwarc = rc->priv;
+	struct usb_interface *iface = hwarc->usb_iface;
+	struct usb_device *usb_dev = interface_to_usbdev(iface);
+	struct device *dev = &iface->dev;
+	int result;
+	struct usb_endpoint_descriptor *epd;
+
+	epd = &iface->cur_altsetting->endpoint[0].desc;
+	hwarc->rd_buffer = (void *) __get_free_page(GFP_KERNEL);
+	if (hwarc->rd_buffer == NULL) {
+		dev_err(dev, "Unable to allocate notification's read buffer\n");
+		goto error_rd_buffer;
+	}
+	hwarc->neep_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (hwarc->neep_urb == NULL) {
+		dev_err(dev, "Unable to allocate notification URB\n");
+		goto error_urb_alloc;
+	}
+	usb_fill_int_urb(hwarc->neep_urb, usb_dev,
+			 usb_rcvintpipe(usb_dev, epd->bEndpointAddress),
+			 hwarc->rd_buffer, PAGE_SIZE,
+			 hwarc_neep_cb, hwarc, epd->bInterval);
+	result = usb_submit_urb(hwarc->neep_urb, GFP_ATOMIC);
+	if (result < 0) {
+		dev_err(dev, "Cannot submit notification URB: %d\n", result);
+		goto error_neep_submit;
+	}
+	return 0;
+
+error_neep_submit:
+	usb_free_urb(hwarc->neep_urb);
+error_urb_alloc:
+	free_page((unsigned long)hwarc->rd_buffer);
+error_rd_buffer:
+	return -ENOMEM;
+}
+
+
+/** Clean up all the notification endpoint resources */
+static void hwarc_neep_release(struct uwb_rc *rc)
+{
+	struct hwarc *hwarc = rc->priv;
+
+	usb_kill_urb(hwarc->neep_urb);
+	usb_free_urb(hwarc->neep_urb);
+	free_page((unsigned long)hwarc->rd_buffer);
+}
+
+/**
+ * Get the version from class-specific descriptor
+ *
+ * NOTE: this descriptor comes with the big bundled configuration
+ *	 descriptor that includes the interfaces' and endpoints', so
+ *	 we just look for it in the cached copy kept by the USB stack.
+ *
+ * NOTE2: We convert LE fields to CPU order.
+ */
+static int hwarc_get_version(struct uwb_rc *rc)
+{
+	int result;
+
+	struct hwarc *hwarc = rc->priv;
+	struct uwb_rc_control_intf_class_desc *descr;
+	struct device *dev = &rc->uwb_dev.dev;
+	struct usb_device *usb_dev = hwarc->usb_dev;
+	char *itr;
+	struct usb_descriptor_header *hdr;
+	size_t itr_size, actconfig_idx;
+	u16 version;
+
+	actconfig_idx = (usb_dev->actconfig - usb_dev->config) /
+		sizeof(usb_dev->config[0]);
+	itr = usb_dev->rawdescriptors[actconfig_idx];
+	itr_size = le16_to_cpu(usb_dev->actconfig->desc.wTotalLength);
+	while (itr_size >= sizeof(*hdr)) {
+		hdr = (struct usb_descriptor_header *) itr;
+		d_printf(3, dev, "Extra device descriptor: "
+			 "type %02x/%u bytes @ %zu (%zu left)\n",
+			 hdr->bDescriptorType, hdr->bLength,
+			 (itr - usb_dev->rawdescriptors[actconfig_idx]),
+			 itr_size);
+		if (hdr->bDescriptorType == USB_DT_CS_RADIO_CONTROL)
+			goto found;
+		itr += hdr->bLength;
+		itr_size -= hdr->bLength;
+	}
+	dev_err(dev, "cannot find Radio Control Interface Class descriptor\n");
+	return -ENODEV;
+
+found:
+	result = -EINVAL;
+	if (hdr->bLength > itr_size) {	/* is it available? */
+		dev_err(dev, "incomplete Radio Control Interface Class "
+			"descriptor (%zu bytes left, %u needed)\n",
+			itr_size, hdr->bLength);
+		goto error;
+	}
+	if (hdr->bLength < sizeof(*descr)) {
+		dev_err(dev, "short Radio Control Interface Class "
+			"descriptor\n");
+		goto error;
+	}
+	descr = (struct uwb_rc_control_intf_class_desc *) hdr;
+	/* Make LE fields CPU order */
+	version = __le16_to_cpu(descr->bcdRCIVersion);
+	if (version != 0x0100) {
+		dev_err(dev, "Device reports protocol version 0x%04x. We "
+			"do not support that. \n", version);
+		result = -EINVAL;
+		goto error;
+	}
+	rc->version = version;
+	d_printf(3, dev, "Device supports WUSB protocol version 0x%04x \n",
+		 rc->version);
+	result = 0;
+error:
+	return result;
+}
+
+/*
+ * By creating a 'uwb_rc', we have a reference on it -- that reference
+ * is the one we drop when we disconnect.
+ *
+ * No need to switch altsettings; according to WUSB1.0[8.6.1.1], there
+ * is only one altsetting allowed.
+ */
+static int hwarc_probe(struct usb_interface *iface,
+		       const struct usb_device_id *id)
+{
+	int result;
+	struct uwb_rc *uwb_rc;
+	struct hwarc *hwarc;
+	struct device *dev = &iface->dev;
+
+	result = -ENOMEM;
+	uwb_rc = uwb_rc_alloc();
+	if (uwb_rc == NULL) {
+		dev_err(dev, "unable to allocate RC instance\n");
+		goto error_rc_alloc;
+	}
+	hwarc = kzalloc(sizeof(*hwarc), GFP_KERNEL);
+	if (hwarc == NULL) {
+		dev_err(dev, "unable to allocate HWA RC instance\n");
+		goto error_alloc;
+	}
+	hwarc_init(hwarc);
+	hwarc->usb_dev = usb_get_dev(interface_to_usbdev(iface));
+	hwarc->usb_iface = usb_get_intf(iface);
+	hwarc->uwb_rc = uwb_rc;
+
+	uwb_rc->owner = THIS_MODULE;
+	uwb_rc->start = hwarc_neep_init;
+	uwb_rc->stop  = hwarc_neep_release;
+	uwb_rc->cmd   = hwarc_cmd;
+	uwb_rc->reset = hwarc_reset;
+	uwb_rc->filter_cmd   = hwarc_filter_cmd;
+	uwb_rc->filter_event = hwarc_filter_event;
+
+	result = uwb_rc_add(uwb_rc, dev, hwarc);
+	if (result < 0)
+		goto error_rc_add;
+	result = hwarc_get_version(uwb_rc);
+	if (result < 0) {
+		dev_err(dev, "cannot retrieve version of RC \n");
+		goto error_get_version;
+	}
+	usb_set_intfdata(iface, hwarc);
+	return 0;
+
+error_get_version:
+	uwb_rc_rm(uwb_rc);
+error_rc_add:
+	usb_put_intf(iface);
+	usb_put_dev(hwarc->usb_dev);
+error_alloc:
+	uwb_rc_put(uwb_rc);
+error_rc_alloc:
+	return result;
+}
+
+static void hwarc_disconnect(struct usb_interface *iface)
+{
+	struct hwarc *hwarc = usb_get_intfdata(iface);
+	struct uwb_rc *uwb_rc = hwarc->uwb_rc;
+
+	usb_set_intfdata(hwarc->usb_iface, NULL);
+	uwb_rc_rm(uwb_rc);
+	usb_put_intf(hwarc->usb_iface);
+	usb_put_dev(hwarc->usb_dev);
+	d_printf(1, &hwarc->usb_iface->dev, "freed hwarc %p\n", hwarc);
+	kfree(hwarc);
+	uwb_rc_put(uwb_rc);	/* when creating the device, refcount = 1 */
+}
+
+/** USB device ID's that we handle */
+static struct usb_device_id hwarc_id_table[] = {
+	{ USB_INTERFACE_INFO(0xe0, 0x01, 0x02), },
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, hwarc_id_table);
+
+static struct usb_driver hwarc_driver = {
+	.name =		"hwa-rc",
+	.probe =	hwarc_probe,
+	.disconnect =	hwarc_disconnect,
+	.id_table =	hwarc_id_table,
+};
+
+static int __init hwarc_driver_init(void)
+{
+	int result;
+	result = usb_register(&hwarc_driver);
+	if (result < 0)
+		printk(KERN_ERR "HWA-RC: Cannot register USB driver: %d\n",
+		       result);
+	return result;
+
+}
+module_init(hwarc_driver_init);
+
+static void __exit hwarc_driver_exit(void)
+{
+	usb_deregister(&hwarc_driver);
+}
+module_exit(hwarc_driver_exit);
+
+MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
+MODULE_DESCRIPTION("Host Wireless Adapter Radio Control Driver");
+MODULE_LICENSE("GPL");