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>

3 files changed, 924 insertions, 0 deletions

diff --git a/drivers/uwb/Kconfig b/drivers/uwb/Kconfig
index c0eb973111ef..a442f39f354c 100644
--- a/drivers/uwb/Kconfig
+++ b/drivers/uwb/Kconfig
@@ -29,6 +29,18 @@ menuconfig UWB
 
 if UWB
 
+config UWB_HWA
+        tristate "UWB Radio Control driver for WUSB-compliant USB dongles (HWA)"
+        depends on USB
+        help
+          This driver enables the radio controller for HWA USB
+          devices. HWA stands for Host Wire Adapter, and it is a UWB
+          Radio Controller connected to your system via USB. Most of
+          them come with a Wireless USB host controller also.
+
+          To compile this driver select Y (built in) or M (module). It
+          is safe to select any even if you do not have the hardware.
+
 config UWB_WHCI
         tristate "UWB Radio Control driver for WHCI-compliant cards"
         depends on PCI
diff --git a/drivers/uwb/Makefile b/drivers/uwb/Makefile
index bdcb494b00e0..6bdb8e7f91ce 100644
--- a/drivers/uwb/Makefile
+++ b/drivers/uwb/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_UWB)               += uwb.o
 obj-$(CONFIG_UWB_WHCI)          += umc.o whci.o whc-rc.o
+obj-$(CONFIG_UWB_HWA)           += hwa-rc.o
 
 uwb-objs :=             \
         address.o       \
diff --git a/drivers/uwb/hwa-rc.c b/drivers/uwb/hwa-rc.c
new file mode 100644
index 000000000000..f822a1872e49
--- /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");