Staging: most: add MOST driver's hdm-usb module
authorChristian Gromm <christian.gromm@microchip.com>
Fri, 24 Jul 2015 14:11:55 +0000 (16:11 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 24 Jul 2015 20:50:43 +0000 (13:50 -0700)
This patch adds the hdm-usb module of the MOST driver to the kernel's
driver staging area. This module is part of the MOST driver and handles
the USB interface of the MOST network interface controller.

This patch is needed in order to use the USB peripheral interface of the
network interface controller.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/most/Kconfig
drivers/staging/most/Makefile
drivers/staging/most/hdm-usb/Kconfig [new file with mode: 0644]
drivers/staging/most/hdm-usb/Makefile [new file with mode: 0644]
drivers/staging/most/hdm-usb/hdm_usb.c [new file with mode: 0644]

index 2a9f92669161080e9a12f20497f200b905e7bcb4..d50de03de7b9897252007d7f35b2e1769bbb2a45 100644 (file)
@@ -25,4 +25,6 @@ source "drivers/staging/most/hdm-dim2/Kconfig"
 
 source "drivers/staging/most/hdm-i2c/Kconfig"
 
+source "drivers/staging/most/hdm-usb/Kconfig"
+
 endif
index 5056f2c8672a9cd0f3cc61d25352c2aa47872974..9ee981c7786b5ad59ca7de341d40e8a7db01cd33 100644 (file)
@@ -5,3 +5,4 @@ obj-$(CONFIG_AIM_SOUND) += aim-sound/
 obj-$(CONFIG_AIM_V4L2) += aim-v4l2/
 obj-$(CONFIG_HDM_DIM2) += hdm-dim2/
 obj-$(CONFIG_HDM_I2C)  += hdm-i2c/
+obj-$(CONFIG_HDM_USB)  += hdm-usb/
diff --git a/drivers/staging/most/hdm-usb/Kconfig b/drivers/staging/most/hdm-usb/Kconfig
new file mode 100644 (file)
index 0000000..a482c3f
--- /dev/null
@@ -0,0 +1,14 @@
+#
+# MOST USB configuration
+#
+
+config HDM_USB
+       tristate "USB HDM"
+       depends on USB
+       select AIM_NETWORK
+       ---help---
+         Say Y here if you want to connect via USB to network tranceiver.
+         This device driver depends on the networking AIM.
+
+         To compile this driver as a module, choose M here: the
+         module will be called hdm_usb.
diff --git a/drivers/staging/most/hdm-usb/Makefile b/drivers/staging/most/hdm-usb/Makefile
new file mode 100644 (file)
index 0000000..6bbacb4
--- /dev/null
@@ -0,0 +1,4 @@
+obj-$(CONFIG_HDM_USB) += hdm_usb.o
+
+ccflags-y += -Idrivers/staging/most/mostcore/
+ccflags-y += -Idrivers/staging/most/aim-network/
diff --git a/drivers/staging/most/hdm-usb/hdm_usb.c b/drivers/staging/most/hdm-usb/hdm_usb.c
new file mode 100644 (file)
index 0000000..a4a3e26
--- /dev/null
@@ -0,0 +1,1442 @@
+/*
+ * 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 */
+/* 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_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);
+
+/**
+ * trigger_resync_vr - Vendor request to trigger HW re-sync mechanism
+ * @dev: usb device
+ *
+ */
+static inline void trigger_resync_vr(struct usb_device *dev)
+{
+       int data = 0;
+
+       if (0 > usb_control_msg(dev,
+                               usb_sndctrlpipe(dev, 0),
+                               0,
+                               USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_ENDPOINT,
+                               0,
+                               0,
+                               &data,
+                               0,
+                               5 * HZ))
+               pr_info("Vendor request \"stall\" failed\n");
+}
+
+/**
+ * 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, void *buf)
+{
+       return usb_control_msg(dev,
+                              usb_rcvctrlpipe(dev, 0),
+                              DRCI_READ_REQ,
+                              USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                              0x0000,
+                              reg,
+                              buf,
+                              2,
+                              5 * HZ);
+}
+
+/**
+ * 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_info("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_info("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.
+ */
+int hdm_poison_channel(struct most_interface *iface, int channel)
+{
+       struct most_dev *mdev;
+
+       if (unlikely(!iface)) {
+               pr_info("Poison: Bad interface.\n");
+               return -EIO;
+       }
+       if (unlikely((channel < 0) || (channel >= iface->num_channels))) {
+               pr_info("Channel ID out of range.\n");
+               return -ECHRNG;
+       }
+
+       mdev = to_mdev(iface);
+       mdev->is_channel_healthy[channel] = false;
+
+       mutex_lock(&mdev->io_mutex);
+       free_anchored_buffers(mdev, channel);
+       if (mdev->padding_active[channel] == true)
+               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
+ */
+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) {
+               pr_err("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.
+ */
+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;
+       unsigned int channel;
+       unsigned long flags;
+
+       mbo = urb->context;
+       anchor = mbo->priv;
+       mdev = to_mdev(mbo->ifp);
+       channel = mbo->hdm_channel_id;
+
+       if ((urb->status == -ENOENT) || (urb->status == -ECONNRESET) ||
+           (mdev->is_channel_healthy[channel] == false)) {
+               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:
+                       pr_info("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 funciton 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;
+       unsigned long flags;
+       unsigned int channel;
+       struct most_channel_config *conf;
+
+       mbo = urb->context;
+       anchor = mbo->priv;
+       mdev = to_mdev(mbo->ifp);
+       channel = mbo->hdm_channel_id;
+
+       if ((urb->status == -ENOENT) || (urb->status == -ECONNRESET) ||
+           (mdev->is_channel_healthy[channel] == false)) {
+               complete(&anchor->urb_compl);
+               return;
+       }
+
+       conf = &mdev->conf[channel];
+
+       if (unlikely(urb->status && !(urb->status == -ENOENT ||
+                                     urb->status == -ECONNRESET ||
+                                     urb->status == -ESHUTDOWN))) {
+               mbo->processed_length = 0;
+               switch (urb->status) {
+               case -EPIPE:
+                       pr_info("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:
+                       pr_info("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] == false) {
+                       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!
+ */
+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;
+       int retval = 0;
+       struct urb *urb;
+       unsigned long flags;
+       unsigned long length;
+       void *virt_address;
+
+       if (unlikely(!iface || !mbo)) {
+               pr_info("Bad interface or MBO\n");
+               return -EIO;
+       }
+       if (unlikely(iface->num_channels <= channel) || (channel < 0)) {
+               pr_info("Channel ID out of range\n");
+               return -ECHRNG;
+       }
+
+       mdev = to_mdev(iface);
+       conf = &mdev->conf[channel];
+
+       if (!mdev->usb_device)
+               return -ENODEV;
+
+       urb = usb_alloc_urb(NO_ISOCHRONOUS_URB, GFP_ATOMIC);
+       if (!urb) {
+               pr_info("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] == true) &&
+           (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,
+                                 hdm_read_completion,
+                                 mbo);
+       }
+       urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+       retval = usb_submit_urb(urb, GFP_KERNEL);
+       if (retval) {
+               pr_info("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
+ */
+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;
+
+       if (unlikely(!iface || !conf)) {
+               pr_info("Bad interface or config pointer.\n");
+               return -EINVAL;
+       }
+       if (unlikely((channel < 0) || (channel >= iface->num_channels))) {
+               pr_info("Channel ID out of range.\n");
+               return -EINVAL;
+       }
+       if ((!conf->num_buffers) || (!conf->buffer_size)) {
+               pr_info("Misconfig: buffer size or number of buffers zero.\n");
+               return -EINVAL;
+       }
+
+       mdev = to_mdev(iface);
+       mdev->is_channel_healthy[channel] = true;
+
+       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;
+
+       if ((conf->data_type != MOST_CH_SYNC) &&
+           (conf->data_type != MOST_CH_ISOC_AVP)) {
+               pr_info("Unsupported data type\n");
+               return -EINVAL;
+       }
+
+       frame_size = get_stream_frame_size(conf);
+       if ((frame_size == 0) || (frame_size > USB_MTU)) {
+               pr_info("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;
+               pr_info("Channel %d - rouding buffer size to %d bytes,"
+                       " channel config says %d bytes",
+                       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.
+ */
+int hdm_update_netinfo(struct most_dev *mdev)
+{
+       int i;
+       u16 link;
+       u8 addr[6];
+
+       if (!is_valid_ether_addr(mdev->hw_addr)) {
+               if (0 > drci_rd_reg(mdev->usb_device,
+                                   DRCI_REG_HW_ADDR_HI, addr)) {
+                       pr_info("Vendor request \"hw_addr_hi\" failed\n");
+                       return -1;
+               }
+               if (0 > drci_rd_reg(mdev->usb_device,
+                                   DRCI_REG_HW_ADDR_MI, addr + 2)) {
+                       pr_info("Vendor request \"hw_addr_mid\" failed\n");
+                       return -1;
+               }
+               if (0 > drci_rd_reg(mdev->usb_device,
+                                   DRCI_REG_HW_ADDR_LO, addr + 4)) {
+                       pr_info("Vendor request \"hw_addr_low\" failed\n");
+                       return -1;
+               }
+               mutex_lock(&mdev->io_mutex);
+               for (i = 0; i < 6; i++)
+                       mdev->hw_addr[i] = addr[i];
+               mutex_unlock(&mdev->io_mutex);
+
+       }
+       if (0 > drci_rd_reg(mdev->usb_device, DRCI_REG_NI_STATE, &link)) {
+               pr_info("Vendor request \"link status\" failed\n");
+               return -1;
+       }
+       le16_to_cpus(&link);
+       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.
+ *
+ */
+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 (0 > hdm_update_netinfo(mdev))
+               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))
+               pr_info("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", le16_to_cpu(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 v16;
+       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, &v16);
+       if (err)
+               return err;
+
+       err = drci_wr_reg(dci_obj->usb_device, reg_addr, cpu_to_le16(v16));
+       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 usb_host_interface *usb_iface_desc;
+       struct usb_endpoint_descriptor *ep_desc;
+       int ret = 0;
+
+       usb_iface_desc = interface->cur_altsetting;
+       usb_dev = interface_to_usbdev(interface);
+       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);
+       init_timer(&mdev->link_stat_timer);
+
+       mdev->usb_device = usb_dev;
+       mdev->link_stat_timer.function = link_stat_timer_handler;
+       mdev->link_stat_timer.data = (unsigned long)mdev;
+       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]);
+       }
+       pr_info("claimed gadget: Vendor=%4.4x ProdID=%4.4x Bus=%02x Device=%02x If#=%d Alt=%d\n",
+               le16_to_cpu(usb_dev->descriptor.idVendor),
+               le16_to_cpu(usb_dev->descriptor.idProduct),
+               usb_dev->bus->busnum,
+               usb_dev->devnum,
+               usb_iface_desc->desc.bInterfaceNumber,
+               usb_iface_desc->desc.bAlternateSetting);
+
+       pr_info("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;
+               trigger_resync_vr(usb_dev);
+       }
+       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;
+               pr_info("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);
+       if (unlikely(!mdev)) {
+               pr_info("failed to retrieve interface data\n");
+               return;
+       }
+
+       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_info("could not register hdm_usb driver\n");
+               return -EIO;
+       }
+       schedule_usb_work = create_workqueue("hdmu_work");
+       if (schedule_usb_work == NULL) {
+               pr_info("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");