// SPDX-License-Identifier: GPL-2.0

  /*

   * usb.c - Hardware dependent module for USB

   *
   * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG

   */

  #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 <linux/most.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 USB_VENDOR_ID_SMSC	0x0424  /* VID: SMSC */
  #define USB_DEV_ID_BRDG		0xC001  /* PID: USB Bridge */

  #define USB_DEV_ID_OS81118	0xCF18  /* PID: USB OS81118 */

  #define USB_DEV_ID_OS81119	0xCF19  /* PID: USB OS81119 */

  #define USB_DEV_ID_OS81210	0xCF30  /* PID: USB OS81210 */

  /* 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 most_dci_obj - Direct Communication Interface
   * @kobj:position in sysfs
   * @usb_device: pointer to the usb device

   * @reg_addr: register address for arbitrary DCI access

   */
  struct most_dci_obj {

  	struct device dev;

  	struct usb_device *usb_device;

  	u16 reg_addr;

  };

  #define to_dci_obj(p) container_of(p, struct most_dci_obj, dev)

  struct most_dev;
  
  struct clear_hold_work {
  	struct work_struct ws;
  	struct most_dev *mdev;
  	unsigned int channel;
  	int pipe;
  };
  
  #define to_clear_hold_work(w) container_of(w, struct clear_hold_work, ws)

  /**
   * struct most_dev - holds all usb interface specific stuff

   * @usb_device: pointer to usb device
   * @iface: hardware interface
   * @cap: channel capabilities
   * @conf: channel configuration
   * @dci: direct communication interface of hardware

   * @ep_address: endpoint address table

   * @description: device description
   * @suffix: suffix for channel name

   * @channel_lock: synchronize channel access

   * @padding_active: indicates channel uses padding
   * @is_channel_healthy: health status table of each channel

   * @busy_urbs: 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 device dev;

  	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 *ep_address;

  	char description[MAX_STRING_LEN];
  	char suffix[MAX_NUM_ENDPOINTS][MAX_SUFFIX_LEN];

  	spinlock_t channel_lock[MAX_NUM_ENDPOINTS]; /* sync channel access */

  	bool padding_active[MAX_NUM_ENDPOINTS];
  	bool is_channel_healthy[MAX_NUM_ENDPOINTS];

  	struct clear_hold_work clear_work[MAX_NUM_ENDPOINTS];

  	struct usb_anchor *busy_urbs;

  	struct mutex io_mutex;
  	struct timer_list link_stat_timer;
  	struct work_struct poll_work_obj;

  	void (*on_netinfo)(struct most_interface *most_iface,
  			   unsigned char link_state, unsigned char *addrs);

  };

  #define to_mdev(d) container_of(d, struct most_dev, iface)

  #define to_mdev_from_dev(d) container_of(d, struct most_dev, dev)

  #define to_mdev_from_work(w) container_of(w, struct most_dev, poll_work_obj)

  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;

  	__le16 *dma_buf;

  	u8 req_type = USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE;

  	dma_buf = kzalloc(sizeof(*dma_buf), GFP_KERNEL);

  	if (!dma_buf)
  		return -ENOMEM;
  
  	retval = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
  				 DRCI_READ_REQ, req_type,
  				 0x0000,

  				 reg, dma_buf, sizeof(*dma_buf), 5 * HZ);

  	*buf = le16_to_cpu(*dma_buf);

  	kfree(dma_buf);

  	if (retval < 0)
  		return retval;
  	return 0;

  }
  
  /**
   * 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);
  }

  static inline int start_sync_ep(struct usb_device *usb_dev, u16 ep)
  {
  	return drci_wr_reg(usb_dev, DRCI_REG_BASE + DRCI_COMMAND + ep * 16, 1);
  }

  /**

   * get_stream_frame_size - calculate frame size of current configuration

   * @dev: device structure

   * @cfg: channel configuration
   */

  static unsigned int get_stream_frame_size(struct device *dev,
  					  struct most_channel_config *cfg)

  {

  	unsigned int frame_size;

  	unsigned int sub_size = cfg->subbuffer_size;
  
  	if (!sub_size) {

  		dev_warn(dev, "Misconfig: Subbuffer size zero.
  ");

  		return 0;

  	}
  	switch (cfg->data_type) {

  	case MOST_CH_ISOC:

  		frame_size = AV_PACKETS_PER_XACT * sub_size;
  		break;
  	case MOST_CH_SYNC:
  		if (cfg->packets_per_xact == 0) {

  			dev_warn(dev, "Misconfig: Packets per XACT zero
  ");

  			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:

  		dev_warn(dev, "Query frame size of non-streaming channel
  ");

  		frame_size = 0;

  		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 = to_mdev(iface);

  	unsigned long flags;
  	spinlock_t *lock; /* temp. lock */

  	if (channel < 0 || channel >= iface->num_channels) {

  		dev_warn(&mdev->usb_device->dev, "Channel ID out of range.
  ");

  		return -ECHRNG;
  	}

  	lock = mdev->channel_lock + channel;

  	spin_lock_irqsave(lock, flags);

  	mdev->is_channel_healthy[channel] = false;

  	spin_unlock_irqrestore(lock, flags);

  	cancel_work_sync(&mdev->clear_work[channel].ws);

  	mutex_lock(&mdev->io_mutex);

  	usb_kill_anchored_urbs(&mdev->busy_urbs[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 frame_size = get_stream_frame_size(&mdev->dev, conf);

  	unsigned int j, num_frames;

  	if (!frame_size)

  		return -EINVAL;

  	num_frames = mbo->buffer_length / frame_size;
  
  	if (num_frames < 1) {

  		dev_err(&mdev->usb_device->dev,
  			"Missed minimal transfer unit.
  ");

  		return -EINVAL;

  	}

  	for (j = num_frames - 1; j > 0; j--)
  		memmove(mbo->virt_address + j * USB_MTU,
  			mbo->virt_address + j * frame_size,

  			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)

  {

  	struct most_channel_config *const conf = &mdev->conf[channel];

  	unsigned int frame_size = get_stream_frame_size(&mdev->dev, conf);

  	unsigned int j, num_frames;

  	if (!frame_size)

  		return -EINVAL;

  	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 = urb->context;

  	struct most_dev *mdev = to_mdev(mbo->ifp);
  	unsigned int channel = mbo->hdm_channel_id;

  	spinlock_t *lock = mdev->channel_lock + channel;

  	unsigned long flags;

  	spin_lock_irqsave(lock, flags);

  	mbo->processed_length = 0;
  	mbo->status = MBO_E_INVAL;
  	if (likely(mdev->is_channel_healthy[channel])) {

  		switch (urb->status) {

  		case 0:
  		case -ESHUTDOWN:
  			mbo->processed_length = urb->actual_length;
  			mbo->status = MBO_SUCCESS;
  			break;

  		case -EPIPE:

  			dev_warn(&mdev->usb_device->dev,
  				 "Broken pipe on ep%02x
  ",

  				 mdev->ep_address[channel]);

  			mdev->is_channel_healthy[channel] = false;

  			mdev->clear_work[channel].pipe = urb->pipe;
  			schedule_work(&mdev->clear_work[channel].ws);

  			break;

  		case -ENODEV:
  		case -EPROTO:
  			mbo->status = MBO_E_CLOSE;
  			break;

  		}

  	}

  	spin_unlock_irqrestore(lock, flags);

  
  	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!

   */
  static void hdm_read_completion(struct urb *urb)
  {

  	struct mbo *mbo = urb->context;

  	struct most_dev *mdev = to_mdev(mbo->ifp);
  	unsigned int channel = mbo->hdm_channel_id;
  	struct device *dev = &mdev->usb_device->dev;

  	spinlock_t *lock = mdev->channel_lock + channel;

  	unsigned long flags;

  	spin_lock_irqsave(lock, flags);

  	mbo->processed_length = 0;
  	mbo->status = MBO_E_INVAL;
  	if (likely(mdev->is_channel_healthy[channel])) {

  		switch (urb->status) {

  		case 0:
  		case -ESHUTDOWN:
  			mbo->processed_length = urb->actual_length;
  			mbo->status = MBO_SUCCESS;
  			if (mdev->padding_active[channel] &&
  			    hdm_remove_padding(mdev, channel, mbo)) {
  				mbo->processed_length = 0;
  				mbo->status = MBO_E_INVAL;
  			}
  			break;

  		case -EPIPE:

  			dev_warn(dev, "Broken pipe on ep%02x
  ",
  				 mdev->ep_address[channel]);

  			mdev->is_channel_healthy[channel] = false;

  			mdev->clear_work[channel].pipe = urb->pipe;
  			schedule_work(&mdev->clear_work[channel].ws);

  			break;

  		case -ENODEV:
  		case -EPROTO:
  			mbo->status = MBO_E_CLOSE;
  			break;
  		case -EOVERFLOW:

  			dev_warn(dev, "Babble on ep%02x
  ",
  				 mdev->ep_address[channel]);

  			break;
  		}

  	}

  	spin_unlock_irqrestore(lock, flags);

  
  	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 = to_mdev(iface);

  	struct most_channel_config *conf;
  	int retval = 0;
  	struct urb *urb;

  	unsigned long length;
  	void *virt_address;

  	if (!mbo)

  		return -EINVAL;

  	if (iface->num_channels <= channel || channel < 0)

  		return -ECHRNG;

  	urb = usb_alloc_urb(NO_ISOCHRONOUS_URB, GFP_KERNEL);
  	if (!urb)
  		return -ENOMEM;

  	conf = &mdev->conf[channel];

  	mutex_lock(&mdev->io_mutex);
  	if (!mdev->usb_device) {
  		retval = -ENODEV;

  		goto err_free_urb;

  	}

  	if ((conf->direction & MOST_CH_TX) && mdev->padding_active[channel] &&
  	    hdm_add_padding(mdev, channel, mbo)) {

  		retval = -EINVAL;

  		goto err_free_urb;

  	}

  
  	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 &&
  		    conf->data_type != MOST_CH_SYNC)

  			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;

  	usb_anchor_urb(urb, &mdev->busy_urbs[channel]);

  	retval = usb_submit_urb(urb, GFP_KERNEL);
  	if (retval) {

  		dev_err(&mdev->usb_device->dev,
  			"URB submit failed with error %d.
  ", retval);

  		goto err_unanchor_urb;

  	}

  	mutex_unlock(&mdev->io_mutex);
  	return 0;

  err_unanchor_urb:

  	usb_unanchor_urb(urb);

  err_free_urb:

  	usb_free_urb(urb);

  	mutex_unlock(&mdev->io_mutex);

  	return retval;
  }

  static void *hdm_dma_alloc(struct mbo *mbo, u32 size)
  {
  	struct most_dev *mdev = to_mdev(mbo->ifp);
  
  	return usb_alloc_coherent(mdev->usb_device, size, GFP_KERNEL,
  				  &mbo->bus_address);
  }
  
  static void hdm_dma_free(struct mbo *mbo, u32 size)
  {
  	struct most_dev *mdev = to_mdev(mbo->ifp);
  
  	usb_free_coherent(mdev->usb_device, size, mbo->virt_address,
  			  mbo->bus_address);
  }

  /**
   * hdm_configure_channel - receive channel configuration from core
   * @iface: interface
   * @channel: channel ID
   * @conf: structure that holds the configuration information

   *
   * The attached network interface controller (NIC) supports a padding mode
   * to avoid short packets on USB, hence increasing the performance due to a
   * lower interrupt load. This mode is default for synchronous data and can
   * be switched on for isochronous data. In case padding is active the
   * driver needs to know the frame size of the payload in order to calculate
   * the number of bytes it needs to pad when transmitting or to cut off when
   * receiving data.
   *

   */

  static int hdm_configure_channel(struct most_interface *iface, int channel,
  				 struct most_channel_config *conf)

  {
  	unsigned int num_frames;
  	unsigned int frame_size;

  	struct most_dev *mdev = to_mdev(iface);
  	struct device *dev = &mdev->usb_device->dev;

  	if (!conf) {

  		dev_err(dev, "Bad config pointer.
  ");

  		return -EINVAL;
  	}

  	if (channel < 0 || channel >= iface->num_channels) {

  		dev_err(dev, "Channel ID out of range.
  ");

  		return -EINVAL;
  	}

  
  	mdev->is_channel_healthy[channel] = true;
  	mdev->clear_work[channel].channel = channel;
  	mdev->clear_work[channel].mdev = mdev;
  	INIT_WORK(&mdev->clear_work[channel].ws, wq_clear_halt);

  	if (!conf->num_buffers || !conf->buffer_size) {

  		dev_err(dev, "Misconfig: buffer size or #buffers zero.
  ");

  		return -EINVAL;
  	}

  	if (conf->data_type != MOST_CH_SYNC &&

  	    !(conf->data_type == MOST_CH_ISOC &&

  	      conf->packets_per_xact != 0xFF)) {

  		mdev->padding_active[channel] = false;

  		/*
  		 * Since the NIC's padding mode is not going to be
  		 * used, we can skip the frame size calculations and
  		 * move directly on to exit.
  		 */

  		goto exit;
  	}
  
  	mdev->padding_active[channel] = true;

  	frame_size = get_stream_frame_size(&mdev->dev, conf);

  	if (frame_size == 0 || frame_size > USB_MTU) {

  		dev_warn(dev, "Misconfig: frame size wrong
  ");

  		return -EINVAL;
  	}

  	num_frames = conf->buffer_size / frame_size;

  	if (conf->buffer_size % frame_size) {

  		u16 old_size = conf->buffer_size;

  		conf->buffer_size = num_frames * frame_size;
  		dev_warn(dev, "%s: fixed buffer size (%d -> %d)
  ",
  			 mdev->suffix[channel], old_size, conf->buffer_size);
  	}

  
  	/* calculate extra length to comply w/ HW padding */

  	conf->extra_len = num_frames * (USB_MTU - frame_size);

  exit:
  	mdev->conf[channel] = *conf;

  	if (conf->data_type == MOST_CH_ASYNC) {
  		u16 ep = mdev->ep_address[channel];

  		if (start_sync_ep(mdev->usb_device, ep) < 0)

  			dev_warn(dev, "sync for ep%02x failed", ep);
  	}

  	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,
  				void (*on_netinfo)(struct most_interface *,
  						   unsigned char,
  						   unsigned char *))

  {

  	struct most_dev *mdev = to_mdev(iface);

  	mdev->on_netinfo = on_netinfo;
  	if (!on_netinfo)
  		return;

  	mdev->link_stat_timer.expires = jiffies + HZ;
  	mod_timer(&mdev->link_stat_timer, mdev->link_stat_timer.expires);
  }
  
  /**

   * link_stat_timer_handler - schedule work obtaining mac address and link status

   * @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(struct timer_list *t)

  {

  	struct most_dev *mdev = from_timer(mdev, t, link_stat_timer);

  	schedule_work(&mdev->poll_work_obj);

  	mdev->link_stat_timer.expires = jiffies + (2 * HZ);
  	add_timer(&mdev->link_stat_timer);
  }
  
  /**

   * wq_netinfo - work queue function to deliver latest networking information

   * @wq_obj: object that holds data for our deferred work to do
   *
   * This retrieves the network interface status of the USB INIC

   */
  static void wq_netinfo(struct work_struct *wq_obj)
  {

  	struct most_dev *mdev = to_mdev_from_work(wq_obj);

  	struct usb_device *usb_device = mdev->usb_device;
  	struct device *dev = &usb_device->dev;
  	u16 hi, mi, lo, link;
  	u8 hw_addr[6];

  	if (drci_rd_reg(usb_device, DRCI_REG_HW_ADDR_HI, &hi)) {

  		dev_err(dev, "Vendor request 'hw_addr_hi' failed
  ");
  		return;
  	}

  	if (drci_rd_reg(usb_device, DRCI_REG_HW_ADDR_MI, &mi)) {

  		dev_err(dev, "Vendor request 'hw_addr_mid' failed
  ");
  		return;
  	}

  	if (drci_rd_reg(usb_device, DRCI_REG_HW_ADDR_LO, &lo)) {

  		dev_err(dev, "Vendor request 'hw_addr_low' failed
  ");
  		return;
  	}

  	if (drci_rd_reg(usb_device, DRCI_REG_NI_STATE, &link)) {

  		dev_err(dev, "Vendor request 'link status' failed
  ");

  		return;

  	}
  
  	hw_addr[0] = hi >> 8;
  	hw_addr[1] = hi;
  	hw_addr[2] = mi >> 8;
  	hw_addr[3] = mi;
  	hw_addr[4] = lo >> 8;
  	hw_addr[5] = lo;

  	if (mdev->on_netinfo)
  		mdev->on_netinfo(&mdev->iface, link, hw_addr);

  }
  
  /**
   * 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 clear_hold_work *clear_work = to_clear_hold_work(wq_obj);
  	struct most_dev *mdev = clear_work->mdev;
  	unsigned int channel = clear_work->channel;
  	int pipe = clear_work->pipe;

  	int snd_pipe;
  	int peer;

  	mutex_lock(&mdev->io_mutex);

  	most_stop_enqueue(&mdev->iface, channel);

  	usb_kill_anchored_urbs(&mdev->busy_urbs[channel]);

  	if (usb_clear_halt(mdev->usb_device, pipe))

  		dev_warn(&mdev->usb_device->dev, "Failed to reset endpoint.
  ");

  	/* If the functional Stall condition has been set on an
  	 * asynchronous rx channel, we need to clear the tx channel
  	 * too, since the hardware runs its clean-up sequence on both
  	 * channels, as they are physically one on the network.
  	 *
  	 * The USB interface that exposes the asynchronous channels
  	 * contains always two endpoints, and two only.
  	 */
  	if (mdev->conf[channel].data_type == MOST_CH_ASYNC &&
  	    mdev->conf[channel].direction == MOST_CH_RX) {

  		if (channel == 0)
  			peer = 1;
  		else
  			peer = 0;
  		snd_pipe = usb_sndbulkpipe(mdev->usb_device,
  					   mdev->ep_address[peer]);

  		usb_clear_halt(mdev->usb_device, snd_pipe);
  	}

  	mdev->is_channel_healthy[channel] = true;

  	most_resume_enqueue(&mdev->iface, channel);

  	mutex_unlock(&mdev->io_mutex);

  }
  
  /**
   * 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 const struct usb_device_id usbid[] = {

  	{ USB_DEVICE(USB_VENDOR_ID_SMSC, USB_DEV_ID_BRDG), },

  	{ USB_DEVICE(USB_VENDOR_ID_SMSC, USB_DEV_ID_OS81118), },

  	{ USB_DEVICE(USB_VENDOR_ID_SMSC, USB_DEV_ID_OS81119), },

  	{ USB_DEVICE(USB_VENDOR_ID_SMSC, USB_DEV_ID_OS81210), },

  	{ } /* Terminating entry */
  };

  struct regs {
  	const char *name;
  	u16 reg;
  };
  
  static const struct regs ro_regs[] = {
  	{ "ni_state", DRCI_REG_NI_STATE },
  	{ "packet_bandwidth", DRCI_REG_PACKET_BW },
  	{ "node_address", DRCI_REG_NODE_ADDR },
  	{ "node_position", DRCI_REG_NODE_POS },
  };
  
  static const struct regs rw_regs[] = {
  	{ "mep_filter", DRCI_REG_MEP_FILTER },
  	{ "mep_hash0", DRCI_REG_HASH_TBL0 },
  	{ "mep_hash1", DRCI_REG_HASH_TBL1 },
  	{ "mep_hash2", DRCI_REG_HASH_TBL2 },
  	{ "mep_hash3", DRCI_REG_HASH_TBL3 },
  	{ "mep_eui48_hi", DRCI_REG_HW_ADDR_HI },
  	{ "mep_eui48_mi", DRCI_REG_HW_ADDR_MI },
  	{ "mep_eui48_lo", DRCI_REG_HW_ADDR_LO },
  };
  
  static int get_stat_reg_addr(const struct regs *regs, int size,
  			     const char *name, u16 *reg_addr)
  {
  	int i;
  
  	for (i = 0; i < size; i++) {

  		if (sysfs_streq(name, regs[i].name)) {

  			*reg_addr = regs[i].reg;
  			return 0;
  		}
  	}

  	return -EINVAL;

  }
  
  #define get_static_reg_addr(regs, name, reg_addr) \
  	get_stat_reg_addr(regs, ARRAY_SIZE(regs), name, reg_addr)

  static ssize_t value_show(struct device *dev, struct device_attribute *attr,

  			  char *buf)

  {

  	const char *name = attr->attr.name;

  	struct most_dci_obj *dci_obj = to_dci_obj(dev);

  	u16 val;

  	u16 reg_addr;
  	int err;

  	if (sysfs_streq(name, "arb_address"))

  		return snprintf(buf, PAGE_SIZE, "%04x
  ", dci_obj->reg_addr);

  	if (sysfs_streq(name, "arb_value"))

  		reg_addr = dci_obj->reg_addr;

  	else if (get_static_reg_addr(ro_regs, name, &reg_addr) &&
  		 get_static_reg_addr(rw_regs, name, &reg_addr))

  		return -EINVAL;

  	err = drci_rd_reg(dci_obj->usb_device, reg_addr, &val);

  	if (err < 0)
  		return err;

  	return snprintf(buf, PAGE_SIZE, "%04x
  ", val);

  }

  static ssize_t value_store(struct device *dev, struct device_attribute *attr,

  			   const char *buf, size_t count)
  {

  	u16 val;

  	u16 reg_addr;

  	const char *name = attr->attr.name;

  	struct most_dci_obj *dci_obj = to_dci_obj(dev);

  	struct usb_device *usb_dev = dci_obj->usb_device;

  	int err;

  	err = kstrtou16(buf, 16, &val);

  	if (err)
  		return err;

  	if (sysfs_streq(name, "arb_address")) {

  		dci_obj->reg_addr = val;
  		return count;
  	}

  	if (sysfs_streq(name, "arb_value"))

  		err = drci_wr_reg(usb_dev, dci_obj->reg_addr, val);

  	else if (sysfs_streq(name, "sync_ep"))

  		err = start_sync_ep(usb_dev, val);

  	else if (!get_static_reg_addr(rw_regs, name, &reg_addr))

  		err = drci_wr_reg(usb_dev, reg_addr, val);
  	else

  		return -EINVAL;

  	if (err < 0)
  		return err;
  
  	return count;
  }

  static DEVICE_ATTR(ni_state, 0444, value_show, NULL);
  static DEVICE_ATTR(packet_bandwidth, 0444, value_show, NULL);
  static DEVICE_ATTR(node_address, 0444, value_show, NULL);
  static DEVICE_ATTR(node_position, 0444, value_show, NULL);
  static DEVICE_ATTR(sync_ep, 0200, NULL, value_store);
  static DEVICE_ATTR(mep_filter, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_hash0, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_hash1, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_hash2, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_hash3, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_eui48_hi, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_eui48_mi, 0644, value_show, value_store);
  static DEVICE_ATTR(mep_eui48_lo, 0644, value_show, value_store);
  static DEVICE_ATTR(arb_address, 0644, value_show, value_store);
  static DEVICE_ATTR(arb_value, 0644, value_show, value_store);

  
  static struct attribute *dci_attrs[] = {
  	&dev_attr_ni_state.attr,
  	&dev_attr_packet_bandwidth.attr,
  	&dev_attr_node_address.attr,
  	&dev_attr_node_position.attr,
  	&dev_attr_sync_ep.attr,
  	&dev_attr_mep_filter.attr,
  	&dev_attr_mep_hash0.attr,
  	&dev_attr_mep_hash1.attr,
  	&dev_attr_mep_hash2.attr,
  	&dev_attr_mep_hash3.attr,
  	&dev_attr_mep_eui48_hi.attr,
  	&dev_attr_mep_eui48_mi.attr,
  	&dev_attr_mep_eui48_lo.attr,
  	&dev_attr_arb_address.attr,
  	&dev_attr_arb_value.attr,

  	NULL,
  };

  ATTRIBUTE_GROUPS(dci);

  static void release_dci(struct device *dev)
  {
  	struct most_dci_obj *dci = to_dci_obj(dev);

  	put_device(dev->parent);

  	kfree(dci);
  }

  static void release_mdev(struct device *dev)
  {
  	struct most_dev *mdev = to_mdev_from_dev(dev);
  
  	kfree(mdev);
  }

  /**
   * 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)
  {

  	struct usb_host_interface *usb_iface_desc = interface->cur_altsetting;
  	struct usb_device *usb_dev = interface_to_usbdev(interface);
  	struct device *dev = &usb_dev->dev;

  	struct most_dev *mdev;

  	unsigned int i;
  	unsigned int num_endpoints;
  	struct most_channel_capability *tmp_cap;

  	struct usb_endpoint_descriptor *ep_desc;

  	int ret = -ENOMEM;

  	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);

  	if (!mdev)

  		return -ENOMEM;

  
  	usb_set_intfdata(interface, mdev);
  	num_endpoints = usb_iface_desc->desc.bNumEndpoints;

  	if (num_endpoints > MAX_NUM_ENDPOINTS) {
  		kfree(mdev);
  		return -EINVAL;
  	}

  	mutex_init(&mdev->io_mutex);
  	INIT_WORK(&mdev->poll_work_obj, wq_netinfo);

  	timer_setup(&mdev->link_stat_timer, link_stat_timer_handler, 0);

  
  	mdev->usb_device = usb_dev;

  	mdev->link_stat_timer.expires = jiffies + (2 * HZ);
  
  	mdev->iface.mod = hdm_usb_fops.owner;

  	mdev->iface.dev = &mdev->dev;

  	mdev->iface.driver_dev = &interface->dev;

  	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.dma_alloc = hdm_dma_alloc;
  	mdev->iface.dma_free = hdm_dma_free;

  	mdev->iface.description = mdev->description;
  	mdev->iface.num_channels = num_endpoints;
  
  	snprintf(mdev->description, sizeof(mdev->description),

  		 "%d-%s:%d.%d",

  		 usb_dev->bus->busnum,
  		 usb_dev->devpath,
  		 usb_dev->config->desc.bConfigurationValue,
  		 usb_iface_desc->desc.bInterfaceNumber);

  	mdev->dev.init_name = mdev->description;
  	mdev->dev.parent = &interface->dev;
  	mdev->dev.release = release_mdev;

  	mdev->conf = kcalloc(num_endpoints, sizeof(*mdev->conf), GFP_KERNEL);
  	if (!mdev->conf)

  		goto err_free_mdev;

  
  	mdev->cap = kcalloc(num_endpoints, sizeof(*mdev->cap), GFP_KERNEL);
  	if (!mdev->cap)

  		goto err_free_conf;

  
  	mdev->iface.channel_vector = mdev->cap;

  	mdev->ep_address =
  		kcalloc(num_endpoints, sizeof(*mdev->ep_address), GFP_KERNEL);
  	if (!mdev->ep_address)

  		goto err_free_cap;

  	mdev->busy_urbs =
  		kcalloc(num_endpoints, sizeof(*mdev->busy_urbs), GFP_KERNEL);
  	if (!mdev->busy_urbs)

  		goto err_free_ep_address;

  
  	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 | MOST_CH_SYNC;

  		if (usb_endpoint_dir_in(ep_desc))

  			tmp_cap->direction = MOST_CH_RX;
  		else
  			tmp_cap->direction = MOST_CH_TX;
  		tmp_cap++;

  		init_usb_anchor(&mdev->busy_urbs[i]);

  		spin_lock_init(&mdev->channel_lock[i]);

  	}

  	dev_dbg(dev, "claimed gadget: Vendor=%4.4x ProdID=%4.4x Bus=%02x Device=%02x
  ",
  		le16_to_cpu(usb_dev->descriptor.idVendor),
  		le16_to_cpu(usb_dev->descriptor.idProduct),
  		usb_dev->bus->busnum,
  		usb_dev->devnum);
  
  	dev_dbg(dev, "device path: /sys/bus/usb/devices/%d-%s:%d.%d
  ",
  		usb_dev->bus->busnum,
  		usb_dev->devpath,
  		usb_dev->config->desc.bConfigurationValue,
  		usb_iface_desc->desc.bInterfaceNumber);

  	ret = most_register_interface(&mdev->iface);
  	if (ret)

  		goto err_free_busy_urbs;

  
  	mutex_lock(&mdev->io_mutex);

  	if (le16_to_cpu(usb_dev->descriptor.idProduct) == USB_DEV_ID_OS81118 ||

  	    le16_to_cpu(usb_dev->descriptor.idProduct) == USB_DEV_ID_OS81119 ||
  	    le16_to_cpu(usb_dev->descriptor.idProduct) == USB_DEV_ID_OS81210) {

  		mdev->dci = kzalloc(sizeof(*mdev->dci), GFP_KERNEL);

  		if (!mdev->dci) {
  			mutex_unlock(&mdev->io_mutex);
  			most_deregister_interface(&mdev->iface);
  			ret = -ENOMEM;

  			goto err_free_busy_urbs;

  		}

  		mdev->dci->dev.init_name = "dci";

  		mdev->dci->dev.parent = get_device(mdev->iface.dev);

  		mdev->dci->dev.groups = dci_groups;

  		mdev->dci->dev.release = release_dci;

  		if (device_register(&mdev->dci->dev)) {
  			mutex_unlock(&mdev->io_mutex);
  			most_deregister_interface(&mdev->iface);
  			ret = -ENOMEM;

  			goto err_free_dci;

  		}

  		mdev->dci->usb_device = mdev->usb_device;

  	}
  	mutex_unlock(&mdev->io_mutex);
  	return 0;

  err_free_dci:

  	put_device(&mdev->dci->dev);

  err_free_busy_urbs:

  	kfree(mdev->busy_urbs);

  err_free_ep_address:

  	kfree(mdev->ep_address);

  err_free_cap:

  	kfree(mdev->cap);

  err_free_conf:

  	kfree(mdev->conf);

  err_free_mdev:

  	put_device(&mdev->dev);

  	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 = 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);

  	if (mdev->dci)
  		device_unregister(&mdev->dci->dev);

  	most_deregister_interface(&mdev->iface);

  	kfree(mdev->busy_urbs);

  	kfree(mdev->cap);
  	kfree(mdev->conf);
  	kfree(mdev->ep_address);

  	put_device(&mdev->dci->dev);

  	put_device(&mdev->dev);

  }

  static int hdm_suspend(struct usb_interface *interface, pm_message_t message)
  {
  	struct most_dev *mdev = usb_get_intfdata(interface);
  	int i;
  
  	mutex_lock(&mdev->io_mutex);
  	for (i = 0; i < mdev->iface.num_channels; i++) {
  		most_stop_enqueue(&mdev->iface, i);
  		usb_kill_anchored_urbs(&mdev->busy_urbs[i]);
  	}
  	mutex_unlock(&mdev->io_mutex);
  	return 0;
  }
  
  static int hdm_resume(struct usb_interface *interface)
  {
  	struct most_dev *mdev = usb_get_intfdata(interface);
  	int i;
  
  	mutex_lock(&mdev->io_mutex);
  	for (i = 0; i < mdev->iface.num_channels; i++)
  		most_resume_enqueue(&mdev->iface, i);
  	mutex_unlock(&mdev->io_mutex);
  	return 0;
  }

  static struct usb_driver hdm_usb = {
  	.name = "hdm_usb",
  	.id_table = usbid,
  	.probe = hdm_probe,
  	.disconnect = hdm_disconnect,

  	.resume = hdm_resume,
  	.suspend = hdm_suspend,

  };

  module_usb_driver(hdm_usb);

  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
  MODULE_DESCRIPTION("HDM_4_USB");