recipes-kernel: add MOST driver kernel modules
[AGL/meta-agl-demo.git] / recipes-kernel / hdm-usb / files / hdm_usb.c
diff --git a/recipes-kernel/hdm-usb/files/hdm_usb.c b/recipes-kernel/hdm-usb/files/hdm_usb.c
new file mode 100644 (file)
index 0000000..41690f8
--- /dev/null
@@ -0,0 +1,1438 @@
+/*
+ * hdm_usb.c - Hardware dependent module for USB
+ *
+ * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
+ *
+ * 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.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/usb.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/completion.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/sysfs.h>
+#include <linux/dma-mapping.h>
+#include <linux/etherdevice.h>
+#include <linux/uaccess.h>
+#include "mostcore.h"
+#include "networking.h"
+
+#define USB_MTU                        512
+#define NO_ISOCHRONOUS_URB     0
+#define AV_PACKETS_PER_XACT    2
+#define BUF_CHAIN_SIZE         0xFFFF
+#define MAX_NUM_ENDPOINTS      30
+#define MAX_SUFFIX_LEN         10
+#define MAX_STRING_LEN         80
+#define MAX_BUF_SIZE           0xFFFF
+#define CEILING(x, y)          (((x) + (y) - 1) / (y))
+
+#define USB_VENDOR_ID_SMSC     0x0424  /* VID: SMSC */
+#define USB_DEV_ID_BRDG                0xC001  /* PID: USB Bridge */
+#define USB_DEV_ID_INIC                0xCF18  /* PID: USB INIC */
+#define HW_RESYNC              0x0000
+/* DRCI Addresses */
+#define DRCI_REG_NI_STATE      0x0100
+#define DRCI_REG_PACKET_BW     0x0101
+#define DRCI_REG_NODE_ADDR     0x0102
+#define DRCI_REG_NODE_POS      0x0103
+#define DRCI_REG_MEP_FILTER    0x0140
+#define DRCI_REG_HASH_TBL0     0x0141
+#define DRCI_REG_HASH_TBL1     0x0142
+#define DRCI_REG_HASH_TBL2     0x0143
+#define DRCI_REG_HASH_TBL3     0x0144
+#define DRCI_REG_HW_ADDR_HI    0x0145
+#define DRCI_REG_HW_ADDR_MI    0x0146
+#define DRCI_REG_HW_ADDR_LO    0x0147
+#define DRCI_REG_BASE          0x1100
+#define DRCI_COMMAND           0x02
+#define DRCI_READ_REQ          0xA0
+#define DRCI_WRITE_REQ         0xA1
+
+/**
+ * struct buf_anchor - used to create a list of pending URBs
+ * @urb: pointer to USB request block
+ * @clear_work_obj:
+ * @list: linked list
+ * @urb_completion:
+ */
+struct buf_anchor {
+       struct urb *urb;
+       struct work_struct clear_work_obj;
+       struct list_head list;
+       struct completion urb_compl;
+};
+
+#define to_buf_anchor(w) container_of(w, struct buf_anchor, clear_work_obj)
+
+/**
+ * struct most_dci_obj - Direct Communication Interface
+ * @kobj:position in sysfs
+ * @usb_device: pointer to the usb device
+ */
+struct most_dci_obj {
+       struct kobject kobj;
+       struct usb_device *usb_device;
+};
+
+#define to_dci_obj(p) container_of(p, struct most_dci_obj, kobj)
+
+/**
+ * struct most_dev - holds all usb interface specific stuff
+ * @parent: parent object in sysfs
+ * @usb_device: pointer to usb device
+ * @iface: hardware interface
+ * @cap: channel capabilities
+ * @conf: channel configuration
+ * @dci: direct communication interface of hardware
+ * @hw_addr: MAC address of hardware
+ * @ep_address: endpoint address table
+ * @link_stat: link status of hardware
+ * @description: device description
+ * @suffix: suffix for channel name
+ * @anchor_list_lock: locks list access
+ * @padding_active: indicates channel uses padding
+ * @is_channel_healthy: health status table of each channel
+ * @anchor_list: list of anchored items
+ * @io_mutex: synchronize I/O with disconnect
+ * @link_stat_timer: timer for link status reports
+ * @poll_work_obj: work for polling link status
+ */
+struct most_dev {
+       struct kobject *parent;
+       struct usb_device *usb_device;
+       struct most_interface iface;
+       struct most_channel_capability *cap;
+       struct most_channel_config *conf;
+       struct most_dci_obj *dci;
+       u8 hw_addr[6];
+       u8 *ep_address;
+       u16 link_stat;
+       char description[MAX_STRING_LEN];
+       char suffix[MAX_NUM_ENDPOINTS][MAX_SUFFIX_LEN];
+       spinlock_t anchor_list_lock[MAX_NUM_ENDPOINTS];
+       bool padding_active[MAX_NUM_ENDPOINTS];
+       bool is_channel_healthy[MAX_NUM_ENDPOINTS];
+       struct list_head *anchor_list;
+       struct mutex io_mutex;
+       struct timer_list link_stat_timer;
+       struct work_struct poll_work_obj;
+};
+
+#define to_mdev(d) container_of(d, struct most_dev, iface)
+#define to_mdev_from_work(w) container_of(w, struct most_dev, poll_work_obj)
+
+static struct workqueue_struct *schedule_usb_work;
+static void wq_clear_halt(struct work_struct *wq_obj);
+static void wq_netinfo(struct work_struct *wq_obj);
+
+/**
+ * drci_rd_reg - read a DCI register
+ * @dev: usb device
+ * @reg: register address
+ * @buf: buffer to store data
+ *
+ * This is reads data from INIC's direct register communication interface
+ */
+static inline int drci_rd_reg(struct usb_device *dev, u16 reg, u16 *buf)
+{
+       int retval;
+       u16 *dma_buf = kzalloc(sizeof(u16), GFP_KERNEL);
+       u8 req_type = USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE;
+
+       if (!dma_buf)
+               return -ENOMEM;
+
+       retval = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+                                DRCI_READ_REQ, req_type,
+                                0x0000,
+                                reg, dma_buf, sizeof(u16), 5 * HZ);
+       *buf = le16_to_cpu(*dma_buf);
+       kfree(dma_buf);
+
+       return retval;
+}
+
+/**
+ * drci_wr_reg - write a DCI register
+ * @dev: usb device
+ * @reg: register address
+ * @data: data to write
+ *
+ * This is writes data to INIC's direct register communication interface
+ */
+static inline int drci_wr_reg(struct usb_device *dev, u16 reg, u16 data)
+{
+       return usb_control_msg(dev,
+                              usb_sndctrlpipe(dev, 0),
+                              DRCI_WRITE_REQ,
+                              USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                              data,
+                              reg,
+                              NULL,
+                              0,
+                              5 * HZ);
+}
+
+/**
+ * free_anchored_buffers - free device's anchored items
+ * @mdev: the device
+ * @channel: channel ID
+ */
+static void free_anchored_buffers(struct most_dev *mdev, unsigned int channel)
+{
+       struct mbo *mbo;
+       struct buf_anchor *anchor, *tmp;
+       unsigned long flags;
+
+       spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+       list_for_each_entry_safe(anchor, tmp, &mdev->anchor_list[channel],
+                                list) {
+               struct urb *urb = anchor->urb;
+
+               spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+               if (likely(urb)) {
+                       mbo = urb->context;
+                       if (!irqs_disabled()) {
+                               usb_kill_urb(urb);
+                       } else {
+                               usb_unlink_urb(urb);
+                               wait_for_completion(&anchor->urb_compl);
+                       }
+                       if ((mbo) && (mbo->complete)) {
+                               mbo->status = MBO_E_CLOSE;
+                               mbo->processed_length = 0;
+                               mbo->complete(mbo);
+                       }
+                       usb_free_urb(urb);
+               }
+               spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+               list_del(&anchor->list);
+               kfree(anchor);
+       }
+       spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+}
+
+/**
+ * get_stream_frame_size - calculate frame size of current configuration
+ * @cfg: channel configuration
+ */
+static unsigned int get_stream_frame_size(struct most_channel_config *cfg)
+{
+       unsigned int frame_size = 0;
+       unsigned int sub_size = cfg->subbuffer_size;
+
+       if (!sub_size) {
+               pr_warn("Misconfig: Subbuffer size zero.\n");
+               return frame_size;
+       }
+       switch (cfg->data_type) {
+       case MOST_CH_ISOC_AVP:
+               frame_size = AV_PACKETS_PER_XACT * sub_size;
+               break;
+       case MOST_CH_SYNC:
+               if (cfg->packets_per_xact == 0) {
+                       pr_warn("Misconfig: Packets per XACT zero\n");
+                       frame_size = 0;
+               } else if (cfg->packets_per_xact == 0xFF) {
+                       frame_size = (USB_MTU / sub_size) * sub_size;
+               } else {
+                       frame_size = cfg->packets_per_xact * sub_size;
+               }
+               break;
+       default:
+               pr_warn("Query frame size of non-streaming channel\n");
+               break;
+       }
+       return frame_size;
+}
+
+/**
+ * hdm_poison_channel - mark buffers of this channel as invalid
+ * @iface: pointer to the interface
+ * @channel: channel ID
+ *
+ * This unlinks all URBs submitted to the HCD,
+ * calls the associated completion function of the core and removes
+ * them from the list.
+ *
+ * Returns 0 on success or error code otherwise.
+ */
+static int hdm_poison_channel(struct most_interface *iface, int channel)
+{
+       struct most_dev *mdev;
+
+       mdev = to_mdev(iface);
+       if (unlikely(!iface)) {
+               dev_warn(&mdev->usb_device->dev, "Poison: Bad interface.\n");
+               return -EIO;
+       }
+       if (unlikely((channel < 0) || (channel >= iface->num_channels))) {
+               dev_warn(&mdev->usb_device->dev, "Channel ID out of range.\n");
+               return -ECHRNG;
+       }
+
+       mdev->is_channel_healthy[channel] = false;
+
+       mutex_lock(&mdev->io_mutex);
+       free_anchored_buffers(mdev, channel);
+       if (mdev->padding_active[channel])
+               mdev->padding_active[channel] = false;
+
+       if (mdev->conf[channel].data_type == MOST_CH_ASYNC) {
+               del_timer_sync(&mdev->link_stat_timer);
+               cancel_work_sync(&mdev->poll_work_obj);
+       }
+       mutex_unlock(&mdev->io_mutex);
+       return 0;
+}
+
+/**
+ * hdm_add_padding - add padding bytes
+ * @mdev: most device
+ * @channel: channel ID
+ * @mbo: buffer object
+ *
+ * This inserts the INIC hardware specific padding bytes into a streaming
+ * channel's buffer
+ */
+static int hdm_add_padding(struct most_dev *mdev, int channel, struct mbo *mbo)
+{
+       struct most_channel_config *conf = &mdev->conf[channel];
+       unsigned int j, num_frames, frame_size;
+       u16 rd_addr, wr_addr;
+
+       frame_size = get_stream_frame_size(conf);
+       if (!frame_size)
+               return -EIO;
+       num_frames = mbo->buffer_length / frame_size;
+
+       if (num_frames < 1) {
+               dev_err(&mdev->usb_device->dev,
+                       "Missed minimal transfer unit.\n");
+               return -EIO;
+       }
+
+       for (j = 1; j < num_frames; j++) {
+               wr_addr = (num_frames - j) * USB_MTU;
+               rd_addr = (num_frames - j) * frame_size;
+               memmove(mbo->virt_address + wr_addr,
+                       mbo->virt_address + rd_addr,
+                       frame_size);
+       }
+       mbo->buffer_length = num_frames * USB_MTU;
+       return 0;
+}
+
+/**
+ * hdm_remove_padding - remove padding bytes
+ * @mdev: most device
+ * @channel: channel ID
+ * @mbo: buffer object
+ *
+ * This takes the INIC hardware specific padding bytes off a streaming
+ * channel's buffer.
+ */
+static int hdm_remove_padding(struct most_dev *mdev, int channel,
+                             struct mbo *mbo)
+{
+       unsigned int j, num_frames, frame_size;
+       struct most_channel_config *const conf = &mdev->conf[channel];
+
+       frame_size = get_stream_frame_size(conf);
+       if (!frame_size)
+               return -EIO;
+       num_frames = mbo->processed_length / USB_MTU;
+
+       for (j = 1; j < num_frames; j++)
+               memmove(mbo->virt_address + frame_size * j,
+                       mbo->virt_address + USB_MTU * j,
+                       frame_size);
+
+       mbo->processed_length = frame_size * num_frames;
+       return 0;
+}
+
+/**
+ * hdm_write_completion - completion function for submitted Tx URBs
+ * @urb: the URB that has been completed
+ *
+ * This checks the status of the completed URB. In case the URB has been
+ * unlinked before, it is immediately freed. On any other error the MBO
+ * transfer flag is set. On success it frees allocated resources and calls
+ * the completion function.
+ *
+ * Context: interrupt!
+ */
+static void hdm_write_completion(struct urb *urb)
+{
+       struct mbo *mbo;
+       struct buf_anchor *anchor;
+       struct most_dev *mdev;
+       struct device *dev;
+       unsigned int channel;
+       unsigned long flags;
+
+       mbo = urb->context;
+       anchor = mbo->priv;
+       mdev = to_mdev(mbo->ifp);
+       channel = mbo->hdm_channel_id;
+       dev = &mdev->usb_device->dev;
+
+       if ((urb->status == -ENOENT) || (urb->status == -ECONNRESET) ||
+           (!mdev->is_channel_healthy[channel])) {
+               complete(&anchor->urb_compl);
+               return;
+       }
+
+       if (unlikely(urb->status && !(urb->status == -ENOENT ||
+                                     urb->status == -ECONNRESET ||
+                                     urb->status == -ESHUTDOWN))) {
+               mbo->processed_length = 0;
+               switch (urb->status) {
+               case -EPIPE:
+                       dev_warn(dev, "Broken OUT pipe detected\n");
+                       most_stop_enqueue(&mdev->iface, channel);
+                       mbo->status = MBO_E_INVAL;
+                       usb_unlink_urb(urb);
+                       INIT_WORK(&anchor->clear_work_obj, wq_clear_halt);
+                       queue_work(schedule_usb_work, &anchor->clear_work_obj);
+                       return;
+               case -ENODEV:
+               case -EPROTO:
+                       mbo->status = MBO_E_CLOSE;
+                       break;
+               default:
+                       mbo->status = MBO_E_INVAL;
+                       break;
+               }
+       } else {
+               mbo->status = MBO_SUCCESS;
+               mbo->processed_length = urb->actual_length;
+       }
+
+       spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+       list_del(&anchor->list);
+       spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+       kfree(anchor);
+
+       if (likely(mbo->complete))
+               mbo->complete(mbo);
+       usb_free_urb(urb);
+}
+
+/**
+ * hdm_read_completion - completion function for submitted Rx URBs
+ * @urb: the URB that has been completed
+ *
+ * This checks the status of the completed URB. In case the URB has been
+ * unlinked before it is immediately freed. On any other error the MBO transfer
+ * flag is set. On success it frees allocated resources, removes
+ * padding bytes -if necessary- and calls the completion function.
+ *
+ * Context: interrupt!
+ *
+ * **************************************************************************
+ *                   Error codes returned by in urb->status
+ *                   or in iso_frame_desc[n].status (for ISO)
+ * *************************************************************************
+ *
+ * USB device drivers may only test urb status values in completion handlers.
+ * This is because otherwise there would be a race between HCDs updating
+ * these values on one CPU, and device drivers testing them on another CPU.
+ *
+ * A transfer's actual_length may be positive even when an error has been
+ * reported.  That's because transfers often involve several packets, so that
+ * one or more packets could finish before an error stops further endpoint I/O.
+ *
+ * For isochronous URBs, the urb status value is non-zero only if the URB is
+ * unlinked, the device is removed, the host controller is disabled or the total
+ * transferred length is less than the requested length and the URB_SHORT_NOT_OK
+ * flag is set.  Completion handlers for isochronous URBs should only see
+ * urb->status set to zero, -ENOENT, -ECONNRESET, -ESHUTDOWN, or -EREMOTEIO.
+ * Individual frame descriptor status fields may report more status codes.
+ *
+ *
+ * 0                   Transfer completed successfully
+ *
+ * -ENOENT             URB was synchronously unlinked by usb_unlink_urb
+ *
+ * -EINPROGRESS                URB still pending, no results yet
+ *                     (That is, if drivers see this it's a bug.)
+ *
+ * -EPROTO (*, **)     a) bitstuff error
+ *                     b) no response packet received within the
+ *                        prescribed bus turn-around time
+ *                     c) unknown USB error
+ *
+ * -EILSEQ (*, **)     a) CRC mismatch
+ *                     b) no response packet received within the
+ *                        prescribed bus turn-around time
+ *                     c) unknown USB error
+ *
+ *                     Note that often the controller hardware does not
+ *                     distinguish among cases a), b), and c), so a
+ *                     driver cannot tell whether there was a protocol
+ *                     error, a failure to respond (often caused by
+ *                     device disconnect), or some other fault.
+ *
+ * -ETIME (**)         No response packet received within the prescribed
+ *                     bus turn-around time.  This error may instead be
+ *                     reported as -EPROTO or -EILSEQ.
+ *
+ * -ETIMEDOUT          Synchronous USB message functions use this code
+ *                     to indicate timeout expired before the transfer
+ *                     completed, and no other error was reported by HC.
+ *
+ * -EPIPE (**)         Endpoint stalled.  For non-control endpoints,
+ *                     reset this status with usb_clear_halt().
+ *
+ * -ECOMM              During an IN transfer, the host controller
+ *                     received data from an endpoint faster than it
+ *                     could be written to system memory
+ *
+ * -ENOSR              During an OUT transfer, the host controller
+ *                     could not retrieve data from system memory fast
+ *                     enough to keep up with the USB data rate
+ *
+ * -EOVERFLOW (*)      The amount of data returned by the endpoint was
+ *                     greater than either the max packet size of the
+ *                     endpoint or the remaining buffer size.  "Babble".
+ *
+ * -EREMOTEIO          The data read from the endpoint did not fill the
+ *                     specified buffer, and URB_SHORT_NOT_OK was set in
+ *                     urb->transfer_flags.
+ *
+ * -ENODEV             Device was removed.  Often preceded by a burst of
+ *                     other errors, since the hub driver doesn't detect
+ *                     device removal events immediately.
+ *
+ * -EXDEV              ISO transfer only partially completed
+ *                     (only set in iso_frame_desc[n].status, not urb->status)
+ *
+ * -EINVAL             ISO madness, if this happens: Log off and go home
+ *
+ * -ECONNRESET         URB was asynchronously unlinked by usb_unlink_urb
+ *
+ * -ESHUTDOWN          The device or host controller has been disabled due
+ *                     to some problem that could not be worked around,
+ *                     such as a physical disconnect.
+ *
+ *
+ * (*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate
+ * hardware problems such as bad devices (including firmware) or cables.
+ *
+ * (**) This is also one of several codes that different kinds of host
+ * controller use to indicate a transfer has failed because of device
+ * disconnect.  In the interval before the hub driver starts disconnect
+ * processing, devices may receive such fault reports for every request.
+ *
+ * See <https://www.kernel.org/doc/Documentation/usb/error-codes.txt>
+ */
+static void hdm_read_completion(struct urb *urb)
+{
+       struct mbo *mbo;
+       struct buf_anchor *anchor;
+       struct most_dev *mdev;
+       struct device *dev;
+       unsigned long flags;
+       unsigned int channel;
+
+       mbo = urb->context;
+       anchor = mbo->priv;
+       mdev = to_mdev(mbo->ifp);
+       channel = mbo->hdm_channel_id;
+       dev = &mdev->usb_device->dev;
+
+       if ((urb->status == -ENOENT) || (urb->status == -ECONNRESET) ||
+           (!mdev->is_channel_healthy[channel])) {
+               complete(&anchor->urb_compl);
+               return;
+       }
+
+       if (unlikely(urb->status && !(urb->status == -ENOENT ||
+                                     urb->status == -ECONNRESET ||
+                                     urb->status == -ESHUTDOWN))) {
+               mbo->processed_length = 0;
+               switch (urb->status) {
+               case -EPIPE:
+                       dev_warn(dev, "Broken IN pipe detected\n");
+                       mbo->status = MBO_E_INVAL;
+                       usb_unlink_urb(urb);
+                       INIT_WORK(&anchor->clear_work_obj, wq_clear_halt);
+                       queue_work(schedule_usb_work, &anchor->clear_work_obj);
+                       return;
+               case -ENODEV:
+               case -EPROTO:
+                       mbo->status = MBO_E_CLOSE;
+                       break;
+               case -EOVERFLOW:
+                       dev_warn(dev, "Babble on IN pipe detected\n");
+               default:
+                       mbo->status = MBO_E_INVAL;
+                       break;
+               }
+       } else {
+               mbo->processed_length = urb->actual_length;
+               if (!mdev->padding_active[channel]) {
+                       mbo->status = MBO_SUCCESS;
+               } else {
+                       if (hdm_remove_padding(mdev, channel, mbo)) {
+                               mbo->processed_length = 0;
+                               mbo->status = MBO_E_INVAL;
+                       } else {
+                               mbo->status = MBO_SUCCESS;
+                       }
+               }
+       }
+       spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+       list_del(&anchor->list);
+       spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+       kfree(anchor);
+
+       if (likely(mbo->complete))
+               mbo->complete(mbo);
+       usb_free_urb(urb);
+}
+
+/**
+ * hdm_enqueue - receive a buffer to be used for data transfer
+ * @iface: interface to enqueue to
+ * @channel: ID of the channel
+ * @mbo: pointer to the buffer object
+ *
+ * This allocates a new URB and fills it according to the channel
+ * that is being used for transmission of data. Before the URB is
+ * submitted it is stored in the private anchor list.
+ *
+ * Returns 0 on success. On any error the URB is freed and a error code
+ * is returned.
+ *
+ * Context: Could in _some_ cases be interrupt!
+ */
+static int hdm_enqueue(struct most_interface *iface, int channel,
+                      struct mbo *mbo)
+{
+       struct most_dev *mdev;
+       struct buf_anchor *anchor;
+       struct most_channel_config *conf;
+       struct device *dev;
+       int retval = 0;
+       struct urb *urb;
+       unsigned long flags;
+       unsigned long length;
+       void *virt_address;
+
+       if (unlikely(!iface || !mbo))
+               return -EIO;
+       if (unlikely(iface->num_channels <= channel) || (channel < 0))
+               return -ECHRNG;
+
+       mdev = to_mdev(iface);
+       conf = &mdev->conf[channel];
+       dev = &mdev->usb_device->dev;
+
+       if (!mdev->usb_device)
+               return -ENODEV;
+
+       urb = usb_alloc_urb(NO_ISOCHRONOUS_URB, GFP_ATOMIC);
+       if (!urb) {
+               dev_err(dev, "Failed to allocate URB\n");
+               return -ENOMEM;
+       }
+
+       anchor = kzalloc(sizeof(*anchor), GFP_ATOMIC);
+       if (!anchor) {
+               retval = -ENOMEM;
+               goto _error;
+       }
+
+       anchor->urb = urb;
+       init_completion(&anchor->urb_compl);
+       mbo->priv = anchor;
+
+       spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+       list_add_tail(&anchor->list, &mdev->anchor_list[channel]);
+       spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+
+       if ((mdev->padding_active[channel]) &&
+           (conf->direction & MOST_CH_TX))
+               if (hdm_add_padding(mdev, channel, mbo)) {
+                       retval = -EIO;
+                       goto _error_1;
+               }
+
+       urb->transfer_dma = mbo->bus_address;
+       virt_address = mbo->virt_address;
+       length = mbo->buffer_length;
+
+       if (conf->direction & MOST_CH_TX) {
+               usb_fill_bulk_urb(urb, mdev->usb_device,
+                                 usb_sndbulkpipe(mdev->usb_device,
+                                                 mdev->ep_address[channel]),
+                                 virt_address,
+                                 length,
+                                 hdm_write_completion,
+                                 mbo);
+               if (conf->data_type != MOST_CH_ISOC_AVP)
+                       urb->transfer_flags |= URB_ZERO_PACKET;
+       } else {
+               usb_fill_bulk_urb(urb, mdev->usb_device,
+                                 usb_rcvbulkpipe(mdev->usb_device,
+                                                 mdev->ep_address[channel]),
+                                 virt_address,
+                                 length + conf->extra_len,
+                                 hdm_read_completion,
+                                 mbo);
+       }
+       urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+       retval = usb_submit_urb(urb, GFP_KERNEL);
+       if (retval) {
+               dev_err(dev, "URB submit failed with error %d.\n", retval);
+               goto _error_1;
+       }
+       return 0;
+
+_error_1:
+       spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+       list_del(&anchor->list);
+       spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+       kfree(anchor);
+_error:
+       usb_free_urb(urb);
+       return retval;
+}
+
+/**
+ * hdm_configure_channel - receive channel configuration from core
+ * @iface: interface
+ * @channel: channel ID
+ * @conf: structure that holds the configuration information
+ */
+static int hdm_configure_channel(struct most_interface *iface, int channel,
+                                struct most_channel_config *conf)
+{
+       unsigned int num_frames;
+       unsigned int frame_size;
+       unsigned int temp_size;
+       unsigned int tail_space;
+       struct most_dev *mdev;
+       struct device *dev;
+
+       mdev = to_mdev(iface);
+       mdev->is_channel_healthy[channel] = true;
+       dev = &mdev->usb_device->dev;
+
+       if (unlikely(!iface || !conf)) {
+               dev_err(dev, "Bad interface or config pointer.\n");
+               return -EINVAL;
+       }
+       if (unlikely((channel < 0) || (channel >= iface->num_channels))) {
+               dev_err(dev, "Channel ID out of range.\n");
+               return -EINVAL;
+       }
+       if ((!conf->num_buffers) || (!conf->buffer_size)) {
+               dev_err(dev, "Misconfig: buffer size or #buffers zero.\n");
+               return -EINVAL;
+       }
+
+       if (!(conf->data_type == MOST_CH_SYNC) &&
+           !((conf->data_type == MOST_CH_ISOC_AVP) &&
+             (conf->packets_per_xact != 0xFF))) {
+               mdev->padding_active[channel] = false;
+               goto exit;
+       }
+
+       mdev->padding_active[channel] = true;
+       temp_size = conf->buffer_size;
+
+       frame_size = get_stream_frame_size(conf);
+       if ((frame_size == 0) || (frame_size > USB_MTU)) {
+               dev_warn(dev, "Misconfig: frame size wrong\n");
+               return -EINVAL;
+       }
+
+       if (conf->buffer_size % frame_size) {
+               u16 tmp_val;
+
+               tmp_val = conf->buffer_size / frame_size;
+               conf->buffer_size = tmp_val * frame_size;
+               dev_notice(dev,
+                          "Channel %d - rounding buffer size to %d bytes, channel config says %d bytes\n",
+                          channel,
+                          conf->buffer_size,
+                          temp_size);
+       }
+
+       num_frames = conf->buffer_size / frame_size;
+       tail_space = num_frames * (USB_MTU - frame_size);
+       temp_size += tail_space;
+
+       /* calculate extra length to comply w/ HW padding */
+       conf->extra_len = (CEILING(temp_size, USB_MTU) * USB_MTU)
+                         - conf->buffer_size;
+exit:
+       mdev->conf[channel] = *conf;
+       return 0;
+}
+
+/**
+ * hdm_update_netinfo - retrieve latest networking information
+ * @mdev: device interface
+ *
+ * This triggers the USB vendor requests to read the hardware address and
+ * the current link status of the attached device.
+ */
+static int hdm_update_netinfo(struct most_dev *mdev)
+{
+       struct usb_device *usb_device = mdev->usb_device;
+       struct device *dev = &usb_device->dev;
+       u16 hi, mi, lo, link;
+
+       if (!is_valid_ether_addr(mdev->hw_addr)) {
+               if (drci_rd_reg(usb_device, DRCI_REG_HW_ADDR_HI, &hi) < 0) {
+                       dev_err(dev, "Vendor request \"hw_addr_hi\" failed\n");
+                       return -1;
+               }
+
+               if (drci_rd_reg(usb_device, DRCI_REG_HW_ADDR_MI, &mi) < 0) {
+                       dev_err(dev, "Vendor request \"hw_addr_mid\" failed\n");
+                       return -1;
+               }
+
+               if (drci_rd_reg(usb_device, DRCI_REG_HW_ADDR_LO, &lo) < 0) {
+                       dev_err(dev, "Vendor request \"hw_addr_low\" failed\n");
+                       return -1;
+               }
+
+               mutex_lock(&mdev->io_mutex);
+               mdev->hw_addr[0] = hi >> 8;
+               mdev->hw_addr[1] = hi;
+               mdev->hw_addr[2] = mi >> 8;
+               mdev->hw_addr[3] = mi;
+               mdev->hw_addr[4] = lo >> 8;
+               mdev->hw_addr[5] = lo;
+               mutex_unlock(&mdev->io_mutex);
+       }
+
+       if (drci_rd_reg(usb_device, DRCI_REG_NI_STATE, &link) < 0) {
+               dev_err(dev, "Vendor request \"link status\" failed\n");
+               return -1;
+       }
+
+       mutex_lock(&mdev->io_mutex);
+       mdev->link_stat = link;
+       mutex_unlock(&mdev->io_mutex);
+       return 0;
+}
+
+/**
+ * hdm_request_netinfo - request network information
+ * @iface: pointer to interface
+ * @channel: channel ID
+ *
+ * This is used as trigger to set up the link status timer that
+ * polls for the NI state of the INIC every 2 seconds.
+ *
+ */
+static void hdm_request_netinfo(struct most_interface *iface, int channel)
+{
+       struct most_dev *mdev;
+
+       BUG_ON(!iface);
+       mdev = to_mdev(iface);
+       mdev->link_stat_timer.expires = jiffies + HZ;
+       mod_timer(&mdev->link_stat_timer, mdev->link_stat_timer.expires);
+}
+
+/**
+ * link_stat_timer_handler - add work to link_stat work queue
+ * @data: pointer to USB device instance
+ *
+ * The handler runs in interrupt context. That's why we need to defer the
+ * tasks to a work queue.
+ */
+static void link_stat_timer_handler(unsigned long data)
+{
+       struct most_dev *mdev = (struct most_dev *)data;
+
+       queue_work(schedule_usb_work, &mdev->poll_work_obj);
+       mdev->link_stat_timer.expires = jiffies + (2 * HZ);
+       add_timer(&mdev->link_stat_timer);
+}
+
+/**
+ * wq_netinfo - work queue function
+ * @wq_obj: object that holds data for our deferred work to do
+ *
+ * This retrieves the network interface status of the USB INIC
+ * and compares it with the current status. If the status has
+ * changed, it updates the status of the core.
+ */
+static void wq_netinfo(struct work_struct *wq_obj)
+{
+       struct most_dev *mdev;
+       int i, prev_link_stat;
+       u8 prev_hw_addr[6];
+
+       mdev = to_mdev_from_work(wq_obj);
+       prev_link_stat = mdev->link_stat;
+
+       for (i = 0; i < 6; i++)
+               prev_hw_addr[i] = mdev->hw_addr[i];
+
+       if (hdm_update_netinfo(mdev) < 0)
+               return;
+       if ((prev_link_stat != mdev->link_stat) ||
+           (prev_hw_addr[0] != mdev->hw_addr[0]) ||
+           (prev_hw_addr[1] != mdev->hw_addr[1]) ||
+           (prev_hw_addr[2] != mdev->hw_addr[2]) ||
+           (prev_hw_addr[3] != mdev->hw_addr[3]) ||
+           (prev_hw_addr[4] != mdev->hw_addr[4]) ||
+           (prev_hw_addr[5] != mdev->hw_addr[5]))
+               most_deliver_netinfo(&mdev->iface, mdev->link_stat,
+                                    &mdev->hw_addr[0]);
+}
+
+/**
+ * wq_clear_halt - work queue function
+ * @wq_obj: work_struct object to execute
+ *
+ * This sends a clear_halt to the given USB pipe.
+ */
+static void wq_clear_halt(struct work_struct *wq_obj)
+{
+       struct buf_anchor *anchor;
+       struct most_dev *mdev;
+       struct mbo *mbo;
+       struct urb *urb;
+       unsigned int channel;
+       unsigned long flags;
+
+       anchor = to_buf_anchor(wq_obj);
+       urb = anchor->urb;
+       mbo = urb->context;
+       mdev = to_mdev(mbo->ifp);
+       channel = mbo->hdm_channel_id;
+
+       if (usb_clear_halt(urb->dev, urb->pipe))
+               dev_warn(&mdev->usb_device->dev, "Failed to reset endpoint.\n");
+
+       usb_free_urb(urb);
+       spin_lock_irqsave(&mdev->anchor_list_lock[channel], flags);
+       list_del(&anchor->list);
+       spin_unlock_irqrestore(&mdev->anchor_list_lock[channel], flags);
+
+       if (likely(mbo->complete))
+               mbo->complete(mbo);
+       if (mdev->conf[channel].direction & MOST_CH_TX)
+               most_resume_enqueue(&mdev->iface, channel);
+
+       kfree(anchor);
+}
+
+/**
+ * hdm_usb_fops - file operation table for USB driver
+ */
+static const struct file_operations hdm_usb_fops = {
+       .owner = THIS_MODULE,
+};
+
+/**
+ * usb_device_id - ID table for HCD device probing
+ */
+static struct usb_device_id usbid[] = {
+       { USB_DEVICE(USB_VENDOR_ID_SMSC, USB_DEV_ID_BRDG), },
+       { USB_DEVICE(USB_VENDOR_ID_SMSC, USB_DEV_ID_INIC), },
+       { } /* Terminating entry */
+};
+
+#define MOST_DCI_RO_ATTR(_name) \
+       struct most_dci_attribute most_dci_attr_##_name = \
+               __ATTR(_name, S_IRUGO, show_value, NULL)
+
+#define MOST_DCI_ATTR(_name) \
+       struct most_dci_attribute most_dci_attr_##_name = \
+               __ATTR(_name, S_IRUGO | S_IWUSR, show_value, store_value)
+
+/**
+ * struct most_dci_attribute - to access the attributes of a dci object
+ * @attr: attributes of a dci object
+ * @show: pointer to the show function
+ * @store: pointer to the store function
+ */
+struct most_dci_attribute {
+       struct attribute attr;
+       ssize_t (*show)(struct most_dci_obj *d,
+                       struct most_dci_attribute *attr,
+                       char *buf);
+       ssize_t (*store)(struct most_dci_obj *d,
+                        struct most_dci_attribute *attr,
+                        const char *buf,
+                        size_t count);
+};
+
+#define to_dci_attr(a) container_of(a, struct most_dci_attribute, attr)
+
+/**
+ * dci_attr_show - show function for dci object
+ * @kobj: pointer to kobject
+ * @attr: pointer to attribute struct
+ * @buf: buffer
+ */
+static ssize_t dci_attr_show(struct kobject *kobj, struct attribute *attr,
+                            char *buf)
+{
+       struct most_dci_attribute *dci_attr = to_dci_attr(attr);
+       struct most_dci_obj *dci_obj = to_dci_obj(kobj);
+
+       if (!dci_attr->show)
+               return -EIO;
+
+       return dci_attr->show(dci_obj, dci_attr, buf);
+}
+
+/**
+ * dci_attr_store - store function for dci object
+ * @kobj: pointer to kobject
+ * @attr: pointer to attribute struct
+ * @buf: buffer
+ * @len: length of buffer
+ */
+static ssize_t dci_attr_store(struct kobject *kobj,
+                             struct attribute *attr,
+                             const char *buf,
+                             size_t len)
+{
+       struct most_dci_attribute *dci_attr = to_dci_attr(attr);
+       struct most_dci_obj *dci_obj = to_dci_obj(kobj);
+
+       if (!dci_attr->store)
+               return -EIO;
+
+       return dci_attr->store(dci_obj, dci_attr, buf, len);
+}
+
+static const struct sysfs_ops most_dci_sysfs_ops = {
+       .show = dci_attr_show,
+       .store = dci_attr_store,
+};
+
+/**
+ * most_dci_release - release function for dci object
+ * @kobj: pointer to kobject
+ *
+ * This frees the memory allocated for the dci object
+ */
+static void most_dci_release(struct kobject *kobj)
+{
+       struct most_dci_obj *dci_obj = to_dci_obj(kobj);
+
+       kfree(dci_obj);
+}
+
+static ssize_t show_value(struct most_dci_obj *dci_obj,
+                         struct most_dci_attribute *attr, char *buf)
+{
+       u16 tmp_val;
+       u16 reg_addr;
+       int err;
+
+       if (!strcmp(attr->attr.name, "ni_state"))
+               reg_addr = DRCI_REG_NI_STATE;
+       else if (!strcmp(attr->attr.name, "packet_bandwidth"))
+               reg_addr = DRCI_REG_PACKET_BW;
+       else if (!strcmp(attr->attr.name, "node_address"))
+               reg_addr = DRCI_REG_NODE_ADDR;
+       else if (!strcmp(attr->attr.name, "node_position"))
+               reg_addr = DRCI_REG_NODE_POS;
+       else if (!strcmp(attr->attr.name, "mep_filter"))
+               reg_addr = DRCI_REG_MEP_FILTER;
+       else if (!strcmp(attr->attr.name, "mep_hash0"))
+               reg_addr = DRCI_REG_HASH_TBL0;
+       else if (!strcmp(attr->attr.name, "mep_hash1"))
+               reg_addr = DRCI_REG_HASH_TBL1;
+       else if (!strcmp(attr->attr.name, "mep_hash2"))
+               reg_addr = DRCI_REG_HASH_TBL2;
+       else if (!strcmp(attr->attr.name, "mep_hash3"))
+               reg_addr = DRCI_REG_HASH_TBL3;
+       else if (!strcmp(attr->attr.name, "mep_eui48_hi"))
+               reg_addr = DRCI_REG_HW_ADDR_HI;
+       else if (!strcmp(attr->attr.name, "mep_eui48_mi"))
+               reg_addr = DRCI_REG_HW_ADDR_MI;
+       else if (!strcmp(attr->attr.name, "mep_eui48_lo"))
+               reg_addr = DRCI_REG_HW_ADDR_LO;
+       else
+               return -EIO;
+
+       err = drci_rd_reg(dci_obj->usb_device, reg_addr, &tmp_val);
+       if (err < 0)
+               return err;
+
+       return snprintf(buf, PAGE_SIZE, "%04x\n", tmp_val);
+}
+
+static ssize_t store_value(struct most_dci_obj *dci_obj,
+                          struct most_dci_attribute *attr,
+                          const char *buf, size_t count)
+{
+       u16 val;
+       u16 reg_addr;
+       int err;
+
+       if (!strcmp(attr->attr.name, "mep_filter"))
+               reg_addr = DRCI_REG_MEP_FILTER;
+       else if (!strcmp(attr->attr.name, "mep_hash0"))
+               reg_addr = DRCI_REG_HASH_TBL0;
+       else if (!strcmp(attr->attr.name, "mep_hash1"))
+               reg_addr = DRCI_REG_HASH_TBL1;
+       else if (!strcmp(attr->attr.name, "mep_hash2"))
+               reg_addr = DRCI_REG_HASH_TBL2;
+       else if (!strcmp(attr->attr.name, "mep_hash3"))
+               reg_addr = DRCI_REG_HASH_TBL3;
+       else if (!strcmp(attr->attr.name, "mep_eui48_hi"))
+               reg_addr = DRCI_REG_HW_ADDR_HI;
+       else if (!strcmp(attr->attr.name, "mep_eui48_mi"))
+               reg_addr = DRCI_REG_HW_ADDR_MI;
+       else if (!strcmp(attr->attr.name, "mep_eui48_lo"))
+               reg_addr = DRCI_REG_HW_ADDR_LO;
+       else
+               return -EIO;
+
+       err = kstrtou16(buf, 16, &val);
+       if (err)
+               return err;
+
+       err = drci_wr_reg(dci_obj->usb_device, reg_addr, val);
+       if (err < 0)
+               return err;
+
+       return count;
+}
+
+static MOST_DCI_RO_ATTR(ni_state);
+static MOST_DCI_RO_ATTR(packet_bandwidth);
+static MOST_DCI_RO_ATTR(node_address);
+static MOST_DCI_RO_ATTR(node_position);
+static MOST_DCI_ATTR(mep_filter);
+static MOST_DCI_ATTR(mep_hash0);
+static MOST_DCI_ATTR(mep_hash1);
+static MOST_DCI_ATTR(mep_hash2);
+static MOST_DCI_ATTR(mep_hash3);
+static MOST_DCI_ATTR(mep_eui48_hi);
+static MOST_DCI_ATTR(mep_eui48_mi);
+static MOST_DCI_ATTR(mep_eui48_lo);
+
+/**
+ * most_dci_def_attrs - array of default attribute files of the dci object
+ */
+static struct attribute *most_dci_def_attrs[] = {
+       &most_dci_attr_ni_state.attr,
+       &most_dci_attr_packet_bandwidth.attr,
+       &most_dci_attr_node_address.attr,
+       &most_dci_attr_node_position.attr,
+       &most_dci_attr_mep_filter.attr,
+       &most_dci_attr_mep_hash0.attr,
+       &most_dci_attr_mep_hash1.attr,
+       &most_dci_attr_mep_hash2.attr,
+       &most_dci_attr_mep_hash3.attr,
+       &most_dci_attr_mep_eui48_hi.attr,
+       &most_dci_attr_mep_eui48_mi.attr,
+       &most_dci_attr_mep_eui48_lo.attr,
+       NULL,
+};
+
+/**
+ * DCI ktype
+ */
+static struct kobj_type most_dci_ktype = {
+       .sysfs_ops = &most_dci_sysfs_ops,
+       .release = most_dci_release,
+       .default_attrs = most_dci_def_attrs,
+};
+
+/**
+ * create_most_dci_obj - allocates a dci object
+ * @parent: parent kobject
+ *
+ * This creates a dci object and registers it with sysfs.
+ * Returns a pointer to the object or NULL when something went wrong.
+ */
+static struct
+most_dci_obj *create_most_dci_obj(struct kobject *parent)
+{
+       struct most_dci_obj *most_dci;
+       int retval;
+
+       most_dci = kzalloc(sizeof(*most_dci), GFP_KERNEL);
+       if (!most_dci)
+               return NULL;
+
+       retval = kobject_init_and_add(&most_dci->kobj, &most_dci_ktype, parent,
+                                     "dci");
+       if (retval) {
+               kobject_put(&most_dci->kobj);
+               return NULL;
+       }
+       return most_dci;
+}
+
+/**
+ * destroy_most_dci_obj - DCI object release function
+ * @p: pointer to dci object
+ */
+static void destroy_most_dci_obj(struct most_dci_obj *p)
+{
+       kobject_put(&p->kobj);
+}
+
+/**
+ * hdm_probe - probe function of USB device driver
+ * @interface: Interface of the attached USB device
+ * @id: Pointer to the USB ID table.
+ *
+ * This allocates and initializes the device instance, adds the new
+ * entry to the internal list, scans the USB descriptors and registers
+ * the interface with the core.
+ * Additionally, the DCI objects are created and the hardware is sync'd.
+ *
+ * Return 0 on success. In case of an error a negative number is returned.
+ */
+static int
+hdm_probe(struct usb_interface *interface, const struct usb_device_id *id)
+{
+       unsigned int i;
+       unsigned int num_endpoints;
+       struct most_channel_capability *tmp_cap;
+       struct most_dev *mdev;
+       struct usb_device *usb_dev;
+       struct device *dev;
+       struct usb_host_interface *usb_iface_desc;
+       struct usb_endpoint_descriptor *ep_desc;
+       int ret = 0;
+       int err;
+
+       usb_iface_desc = interface->cur_altsetting;
+       usb_dev = interface_to_usbdev(interface);
+       dev = &usb_dev->dev;
+       mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+       if (!mdev)
+               goto exit_ENOMEM;
+
+       usb_set_intfdata(interface, mdev);
+       num_endpoints = usb_iface_desc->desc.bNumEndpoints;
+       mutex_init(&mdev->io_mutex);
+       INIT_WORK(&mdev->poll_work_obj, wq_netinfo);
+       setup_timer(&mdev->link_stat_timer, link_stat_timer_handler,
+                   (unsigned long)mdev);
+
+       mdev->usb_device = usb_dev;
+       mdev->link_stat_timer.expires = jiffies + (2 * HZ);
+
+       mdev->iface.mod = hdm_usb_fops.owner;
+       mdev->iface.interface = ITYPE_USB;
+       mdev->iface.configure = hdm_configure_channel;
+       mdev->iface.request_netinfo = hdm_request_netinfo;
+       mdev->iface.enqueue = hdm_enqueue;
+       mdev->iface.poison_channel = hdm_poison_channel;
+       mdev->iface.description = mdev->description;
+       mdev->iface.num_channels = num_endpoints;
+
+       snprintf(mdev->description, sizeof(mdev->description),
+                "usb_device %d-%s:%d.%d",
+                usb_dev->bus->busnum,
+                usb_dev->devpath,
+                usb_dev->config->desc.bConfigurationValue,
+                usb_iface_desc->desc.bInterfaceNumber);
+
+       mdev->conf = kcalloc(num_endpoints, sizeof(*mdev->conf), GFP_KERNEL);
+       if (!mdev->conf)
+               goto exit_free;
+
+       mdev->cap = kcalloc(num_endpoints, sizeof(*mdev->cap), GFP_KERNEL);
+       if (!mdev->cap)
+               goto exit_free1;
+
+       mdev->iface.channel_vector = mdev->cap;
+       mdev->iface.priv = NULL;
+
+       mdev->ep_address =
+               kcalloc(num_endpoints, sizeof(*mdev->ep_address), GFP_KERNEL);
+       if (!mdev->ep_address)
+               goto exit_free2;
+
+       mdev->anchor_list =
+               kcalloc(num_endpoints, sizeof(*mdev->anchor_list), GFP_KERNEL);
+       if (!mdev->anchor_list)
+               goto exit_free3;
+
+       tmp_cap = mdev->cap;
+       for (i = 0; i < num_endpoints; i++) {
+               ep_desc = &usb_iface_desc->endpoint[i].desc;
+               mdev->ep_address[i] = ep_desc->bEndpointAddress;
+               mdev->padding_active[i] = false;
+               mdev->is_channel_healthy[i] = true;
+
+               snprintf(&mdev->suffix[i][0], MAX_SUFFIX_LEN, "ep%02x",
+                        mdev->ep_address[i]);
+
+               tmp_cap->name_suffix = &mdev->suffix[i][0];
+               tmp_cap->buffer_size_packet = MAX_BUF_SIZE;
+               tmp_cap->buffer_size_streaming = MAX_BUF_SIZE;
+               tmp_cap->num_buffers_packet = BUF_CHAIN_SIZE;
+               tmp_cap->num_buffers_streaming = BUF_CHAIN_SIZE;
+               tmp_cap->data_type = MOST_CH_CONTROL | MOST_CH_ASYNC |
+                                    MOST_CH_ISOC_AVP | MOST_CH_SYNC;
+               if (ep_desc->bEndpointAddress & USB_DIR_IN)
+                       tmp_cap->direction = MOST_CH_RX;
+               else
+                       tmp_cap->direction = MOST_CH_TX;
+               tmp_cap++;
+               INIT_LIST_HEAD(&mdev->anchor_list[i]);
+               spin_lock_init(&mdev->anchor_list_lock[i]);
+               err = drci_wr_reg(usb_dev,
+                                 DRCI_REG_BASE + DRCI_COMMAND +
+                                 ep_desc->bEndpointAddress * 16,
+                                 1);
+               if (err < 0)
+                       pr_warn("DCI Sync for EP %02x failed",
+                               ep_desc->bEndpointAddress);
+       }
+       dev_notice(dev, "claimed gadget: Vendor=%4.4x ProdID=%4.4x Bus=%02x Device=%02x\n",
+                  le16_to_cpu(usb_dev->descriptor.idVendor),
+                  le16_to_cpu(usb_dev->descriptor.idProduct),
+                  usb_dev->bus->busnum,
+                  usb_dev->devnum);
+
+       dev_notice(dev, "device path: /sys/bus/usb/devices/%d-%s:%d.%d\n",
+                  usb_dev->bus->busnum,
+                  usb_dev->devpath,
+                  usb_dev->config->desc.bConfigurationValue,
+                  usb_iface_desc->desc.bInterfaceNumber);
+
+       mdev->parent = most_register_interface(&mdev->iface);
+       if (IS_ERR(mdev->parent)) {
+               ret = PTR_ERR(mdev->parent);
+               goto exit_free4;
+       }
+
+       mutex_lock(&mdev->io_mutex);
+       if (le16_to_cpu(usb_dev->descriptor.idProduct) == USB_DEV_ID_INIC) {
+               /* this increments the reference count of the instance
+                * object of the core
+                */
+               mdev->dci = create_most_dci_obj(mdev->parent);
+               if (!mdev->dci) {
+                       mutex_unlock(&mdev->io_mutex);
+                       most_deregister_interface(&mdev->iface);
+                       ret = -ENOMEM;
+                       goto exit_free4;
+               }
+
+               kobject_uevent(&mdev->dci->kobj, KOBJ_ADD);
+               mdev->dci->usb_device = mdev->usb_device;
+       }
+       mutex_unlock(&mdev->io_mutex);
+       return 0;
+
+exit_free4:
+       kfree(mdev->anchor_list);
+exit_free3:
+       kfree(mdev->ep_address);
+exit_free2:
+       kfree(mdev->cap);
+exit_free1:
+       kfree(mdev->conf);
+exit_free:
+       kfree(mdev);
+exit_ENOMEM:
+       if (ret == 0 || ret == -ENOMEM) {
+               ret = -ENOMEM;
+               dev_err(dev, "out of memory\n");
+       }
+       return ret;
+}
+
+/**
+ * hdm_disconnect - disconnect function of USB device driver
+ * @interface: Interface of the attached USB device
+ *
+ * This deregisters the interface with the core, removes the kernel timer
+ * and frees resources.
+ *
+ * Context: hub kernel thread
+ */
+static void hdm_disconnect(struct usb_interface *interface)
+{
+       struct most_dev *mdev;
+
+       mdev = usb_get_intfdata(interface);
+       mutex_lock(&mdev->io_mutex);
+       usb_set_intfdata(interface, NULL);
+       mdev->usb_device = NULL;
+       mutex_unlock(&mdev->io_mutex);
+
+       del_timer_sync(&mdev->link_stat_timer);
+       cancel_work_sync(&mdev->poll_work_obj);
+
+       destroy_most_dci_obj(mdev->dci);
+       most_deregister_interface(&mdev->iface);
+
+       kfree(mdev->anchor_list);
+       kfree(mdev->cap);
+       kfree(mdev->conf);
+       kfree(mdev->ep_address);
+       kfree(mdev);
+}
+
+static struct usb_driver hdm_usb = {
+       .name = "hdm_usb",
+       .id_table = usbid,
+       .probe = hdm_probe,
+       .disconnect = hdm_disconnect,
+};
+
+static int __init hdm_usb_init(void)
+{
+       pr_info("hdm_usb_init()\n");
+       if (usb_register(&hdm_usb)) {
+               pr_err("could not register hdm_usb driver\n");
+               return -EIO;
+       }
+       schedule_usb_work = create_workqueue("hdmu_work");
+       if (!schedule_usb_work) {
+               pr_err("could not create workqueue\n");
+               usb_deregister(&hdm_usb);
+               return -ENOMEM;
+       }
+       return 0;
+}
+
+static void __exit hdm_usb_exit(void)
+{
+       pr_info("hdm_usb_exit()\n");
+       destroy_workqueue(schedule_usb_work);
+       usb_deregister(&hdm_usb);
+}
+
+module_init(hdm_usb_init);
+module_exit(hdm_usb_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
+MODULE_DESCRIPTION("HDM_4_USB");