text: /*
   * f_ncm.c -- USB CDC Network (NCM) link function driver
   *
   * Copyright (C) 2010 Nokia Corporation
   * Contact: Yauheni Kaliuta <yauheni.kaliuta@nokia.com>
   *
   * The driver borrows from f_ecm.c which is:
   *
   * Copyright (C) 2003-2005,2008 David Brownell
   * Copyright (C) 2008 Nokia Corporation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  
  #include <linux/kernel.h>
  #include <linux/device.h>
  #include <linux/etherdevice.h>
  #include <linux/crc32.h>
  
  #include <linux/usb/cdc.h>
  
  #include "u_ether.h"
  
  #undef DBG
  #undef VDBG
  #undef ERROR
  #undef INFO
  
  #define DBG(d, fmt, args...) \
  	dev_dbg(&(d)->gadget->dev , fmt , ## args)
  #define VDBG(d, fmt, args...) \
  	dev_vdbg(&(d)->gadget->dev , fmt , ## args)
  #define ERROR(d, fmt, args...) \
  	dev_err(&(d)->gadget->dev , fmt , ## args)
  #define WARNING(d, fmt, args...) \
  	dev_warn(&(d)->gadget->dev , fmt , ## args)
  #define INFO(d, fmt, args...) \
  	dev_info(&(d)->gadget->dev , fmt , ## args)
  /*
   * This function is a "CDC Network Control Model" (CDC NCM) Ethernet link.
   * NCM is intended to be used with high-speed network attachments.
   *
   * Note that NCM requires the use of "alternate settings" for its data
   * interface.  This means that the set_alt() method has real work to do,
   * and also means that a get_alt() method is required.
   */
  
  /* to trigger crc/non-crc ndp signature */
  
  #define NCM_NDP_HDR_CRC_MASK	0x01000000
  #define NCM_NDP_HDR_CRC		0x01000000
  #define NCM_NDP_HDR_NOCRC	0x00000000
  
  enum ncm_notify_state {
  	NCM_NOTIFY_NONE,		/* don't notify */
  	NCM_NOTIFY_CONNECT,		/* issue CONNECT next */
  	NCM_NOTIFY_SPEED,		/* issue SPEED_CHANGE next */
  };
  
  struct f_ncm {
  	struct gether			port;
  	u8				ctrl_id, data_id;
  
  	char				ethaddr[14];
  
  	struct usb_ep			*notify;
  	struct usb_request		*notify_req;
  	u8				notify_state;
  	bool				is_open;
  
  	struct ndp_parser_opts		*parser_opts;
  	bool				is_crc;
  
  	/*
  	 * for notification, it is accessed from both
  	 * callback and ethernet open/close
  	 */
  	spinlock_t			lock;
  };
  
  static inline struct f_ncm *func_to_ncm(struct usb_function *f)
  {
  	return container_of(f, struct f_ncm, port.func);
  }
  
  /* peak (theoretical) bulk transfer rate in bits-per-second */
  static inline unsigned ncm_bitrate(struct usb_gadget *g)
  {
  	if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
  		return 13 * 512 * 8 * 1000 * 8;
  	else
  		return 19 *  64 * 1 * 1000 * 8;
  }
  
  /*-------------------------------------------------------------------------*/
  
  /*
   * We cannot group frames so use just the minimal size which ok to put
   * one max-size ethernet frame.
   * If the host can group frames, allow it to do that, 16K is selected,
   * because it's used by default by the current linux host driver
   */
  #define NTB_DEFAULT_IN_SIZE	USB_CDC_NCM_NTB_MIN_IN_SIZE
  #define NTB_OUT_SIZE		16384
  
  /*
   * skbs of size less than that will not be aligned
   * to NCM's dwNtbInMaxSize to save bus bandwidth
   */
  
  #define	MAX_TX_NONFIXED		(512 * 3)
  
  #define FORMATS_SUPPORTED	(USB_CDC_NCM_NTB16_SUPPORTED |	\
  				 USB_CDC_NCM_NTB32_SUPPORTED)
  
  static struct usb_cdc_ncm_ntb_parameters ntb_parameters = {
  	.wLength = sizeof ntb_parameters,
  	.bmNtbFormatsSupported = cpu_to_le16(FORMATS_SUPPORTED),
  	.dwNtbInMaxSize = cpu_to_le32(NTB_DEFAULT_IN_SIZE),
  	.wNdpInDivisor = cpu_to_le16(4),
  	.wNdpInPayloadRemainder = cpu_to_le16(0),
  	.wNdpInAlignment = cpu_to_le16(4),
  
  	.dwNtbOutMaxSize = cpu_to_le32(NTB_OUT_SIZE),
  	.wNdpOutDivisor = cpu_to_le16(4),
  	.wNdpOutPayloadRemainder = cpu_to_le16(0),
  	.wNdpOutAlignment = cpu_to_le16(4),
  };
  
  /*
   * Use wMaxPacketSize big enough to fit CDC_NOTIFY_SPEED_CHANGE in one
   * packet, to simplify cancellation; and a big transfer interval, to
   * waste less bandwidth.
   */
  
  #define LOG2_STATUS_INTERVAL_MSEC	5	/* 1 << 5 == 32 msec */
  #define NCM_STATUS_BYTECOUNT		16	/* 8 byte header + data */
  
  static struct usb_interface_assoc_descriptor ncm_iad_desc = {
  	.bLength =		sizeof ncm_iad_desc,
  	.bDescriptorType =	USB_DT_INTERFACE_ASSOCIATION,
  
  	/* .bFirstInterface =	DYNAMIC, */
  	.bInterfaceCount =	2,	/* control + data */
  	.bFunctionClass =	USB_CLASS_COMM,
  	.bFunctionSubClass =	USB_CDC_SUBCLASS_NCM,
  	.bFunctionProtocol =	USB_CDC_PROTO_NONE,
  	/* .iFunction =		DYNAMIC */
  };
  
  /* interface descriptor: */
  
  static struct usb_interface_descriptor ncm_control_intf = {
  	.bLength =		sizeof ncm_control_intf,
  	.bDescriptorType =	USB_DT_INTERFACE,
  
  	/* .bInterfaceNumber = DYNAMIC */
  	.bNumEndpoints =	1,
  	.bInterfaceClass =	USB_CLASS_COMM,
  	.bInterfaceSubClass =	USB_CDC_SUBCLASS_NCM,
  	.bInterfaceProtocol =	USB_CDC_PROTO_NONE,
  	/* .iInterface = DYNAMIC */
  };
  
  static struct usb_cdc_header_desc ncm_header_desc = {
  	.bLength =		sizeof ncm_header_desc,
  	.bDescriptorType =	USB_DT_CS_INTERFACE,
  	.bDescriptorSubType =	USB_CDC_HEADER_TYPE,
  
  	.bcdCDC =		cpu_to_le16(0x0110),
  };
  
  static struct usb_cdc_union_desc ncm_union_desc = {
  	.bLength =		sizeof(ncm_union_desc),
  	.bDescriptorType =	USB_DT_CS_INTERFACE,
  	.bDescriptorSubType =	USB_CDC_UNION_TYPE,
  	/* .bMasterInterface0 =	DYNAMIC */
  	/* .bSlaveInterface0 =	DYNAMIC */
  };
  
  static struct usb_cdc_ether_desc necm_desc = {
  	.bLength =		sizeof necm_desc,
  	.bDescriptorType =	USB_DT_CS_INTERFACE,
  	.bDescriptorSubType =	USB_CDC_ETHERNET_TYPE,
  
  	/* this descriptor actually adds value, surprise! */
  	/* .iMACAddress = DYNAMIC */
  	.bmEthernetStatistics =	cpu_to_le32(0), /* no statistics */
  	.wMaxSegmentSize =	cpu_to_le16(ETH_FRAME_LEN),
  	.wNumberMCFilters =	cpu_to_le16(0),
  	.bNumberPowerFilters =	0,
  };
  
  #define NCAPS	(USB_CDC_NCM_NCAP_ETH_FILTER | USB_CDC_NCM_NCAP_CRC_MODE)
  
  static struct usb_cdc_ncm_desc ncm_desc = {
  	.bLength =		sizeof ncm_desc,
  	.bDescriptorType =	USB_DT_CS_INTERFACE,
  	.bDescriptorSubType =	USB_CDC_NCM_TYPE,
  
  	.bcdNcmVersion =	cpu_to_le16(0x0100),
  	/* can process SetEthernetPacketFilter */
  	.bmNetworkCapabilities = NCAPS,
  };
  
  /* the default data interface has no endpoints ... */
  
  static struct usb_interface_descriptor ncm_data_nop_intf = {
  	.bLength =		sizeof ncm_data_nop_intf,
  	.bDescriptorType =	USB_DT_INTERFACE,
  
  	.bInterfaceNumber =	1,
  	.bAlternateSetting =	0,
  	.bNumEndpoints =	0,
  	.bInterfaceClass =	USB_CLASS_CDC_DATA,
  	.bInterfaceSubClass =	0,
  	.bInterfaceProtocol =	USB_CDC_NCM_PROTO_NTB,
  	/* .iInterface = DYNAMIC */
  };
  
  /* ... but the "real" data interface has two bulk endpoints */
  
  static struct usb_interface_descriptor ncm_data_intf = {
  	.bLength =		sizeof ncm_data_intf,
  	.bDescriptorType =	USB_DT_INTERFACE,
  
  	.bInterfaceNumber =	1,
  	.bAlternateSetting =	1,
  	.bNumEndpoints =	2,
  	.bInterfaceClass =	USB_CLASS_CDC_DATA,
  	.bInterfaceSubClass =	0,
  	.bInterfaceProtocol =	USB_CDC_NCM_PROTO_NTB,
  	/* .iInterface = DYNAMIC */
  };
  
  /* full speed support: */
  
  static struct usb_endpoint_descriptor fs_ncm_notify_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_INT,
  	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
  	.bInterval =		1 << LOG2_STATUS_INTERVAL_MSEC,
  };
  
  static struct usb_endpoint_descriptor fs_ncm_in_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  };
  
  static struct usb_endpoint_descriptor fs_ncm_out_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  };
  
  static struct usb_descriptor_header *ncm_fs_function[] = {
  	(struct usb_descriptor_header *) &ncm_iad_desc,
  	/* CDC NCM control descriptors */
  	(struct usb_descriptor_header *) &ncm_control_intf,
  	(struct usb_descriptor_header *) &ncm_header_desc,
  	(struct usb_descriptor_header *) &ncm_union_desc,
  	(struct usb_descriptor_header *) &necm_desc,
  	(struct usb_descriptor_header *) &ncm_desc,
  	(struct usb_descriptor_header *) &fs_ncm_notify_desc,
  	/* data interface, altsettings 0 and 1 */
  	(struct usb_descriptor_header *) &ncm_data_nop_intf,
  	(struct usb_descriptor_header *) &ncm_data_intf,
  	(struct usb_descriptor_header *) &fs_ncm_in_desc,
  	(struct usb_descriptor_header *) &fs_ncm_out_desc,
  	NULL,
  };
  
  /* high speed support: */
  
  static struct usb_endpoint_descriptor hs_ncm_notify_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_INT,
  	.wMaxPacketSize =	cpu_to_le16(NCM_STATUS_BYTECOUNT),
  	.bInterval =		LOG2_STATUS_INTERVAL_MSEC + 4,
  };
  static struct usb_endpoint_descriptor hs_ncm_in_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  
  	.bEndpointAddress =	USB_DIR_IN,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(512),
  };
  
  static struct usb_endpoint_descriptor hs_ncm_out_desc = {
  	.bLength =		USB_DT_ENDPOINT_SIZE,
  	.bDescriptorType =	USB_DT_ENDPOINT,
  
  	.bEndpointAddress =	USB_DIR_OUT,
  	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
  	.wMaxPacketSize =	cpu_to_le16(512),
  };
  
  static struct usb_descriptor_header *ncm_hs_function[] = {
  	(struct usb_descriptor_header *) &ncm_iad_desc,
  	/* CDC NCM control descriptors */
  	(struct usb_descriptor_header *) &ncm_control_intf,
  	(struct usb_descriptor_header *) &ncm_header_desc,
  	(struct usb_descriptor_header *) &ncm_union_desc,
  	(struct usb_descriptor_header *) &necm_desc,
  	(struct usb_descriptor_header *) &ncm_desc,
  	(struct usb_descriptor_header *) &hs_ncm_notify_desc,
  	/* data interface, altsettings 0 and 1 */
  	(struct usb_descriptor_header *) &ncm_data_nop_intf,
  	(struct usb_descriptor_header *) &ncm_data_intf,
  	(struct usb_descriptor_header *) &hs_ncm_in_desc,
  	(struct usb_descriptor_header *) &hs_ncm_out_desc,
  	NULL,
  };
  
  /* string descriptors: */
  
  #define STRING_CTRL_IDX	0
  #define STRING_MAC_IDX	1
  #define NCM_STRING_DATA_IDX	2
  #define STRING_IAD_IDX	3
  
  static struct usb_string ncm_string_defs[] = {
  	[STRING_CTRL_IDX].s = "CDC Network Control Model (NCM)",
  	[STRING_MAC_IDX].s = NULL /* DYNAMIC */,
  	[NCM_STRING_DATA_IDX].s = "CDC Network Data",
  	[STRING_IAD_IDX].s = "CDC NCM",
  	{  } /* end of list */
  };
  
  static struct usb_gadget_strings ncm_string_table = {
  	.language =		0x0409,	/* en-us */
  	.strings =		ncm_string_defs,
  };
  
  static struct usb_gadget_strings *ncm_strings[] = {
  	&ncm_string_table,
  	NULL,
  };
  
  /*
   * Here are options for NCM Datagram Pointer table (NDP) parser.
   * There are 2 different formats: NDP16 and NDP32 in the spec (ch. 3),
   * in NDP16 offsets and sizes fields are 1 16bit word wide,
   * in NDP32 -- 2 16bit words wide. Also signatures are different.
   * To make the parser code the same, put the differences in the structure,
   * and switch pointers to the structures when the format is changed.
   */
  
  struct ndp_parser_opts {
  	u32		nth_sign;
  	u32		ndp_sign;
  	unsigned	nth_size;
  	unsigned	ndp_size;
  	unsigned	ndplen_align;
  	/* sizes in u16 units */
  	unsigned	dgram_item_len; /* index or length */
  	unsigned	block_length;
  	unsigned	fp_index;
  	unsigned	reserved1;
  	unsigned	reserved2;
  	unsigned	next_fp_index;
  };
  
  #define INIT_NDP16_OPTS {					\
  		.nth_sign = USB_CDC_NCM_NTH16_SIGN,		\
  		.ndp_sign = USB_CDC_NCM_NDP16_NOCRC_SIGN,	\
  		.nth_size = sizeof(struct usb_cdc_ncm_nth16),	\
  		.ndp_size = sizeof(struct usb_cdc_ncm_ndp16),	\
  		.ndplen_align = 4,				\
  		.dgram_item_len = 1,				\
  		.block_length = 1,				\
  		.fp_index = 1,					\
  		.reserved1 = 0,					\
  		.reserved2 = 0,					\
  		.next_fp_index = 1,				\
  	}
  
  
  #define INIT_NDP32_OPTS {					\
  		.nth_sign = USB_CDC_NCM_NTH32_SIGN,		\
  		.ndp_sign = USB_CDC_NCM_NDP32_NOCRC_SIGN,	\
  		.nth_size = sizeof(struct usb_cdc_ncm_nth32),	\
  		.ndp_size = sizeof(struct usb_cdc_ncm_ndp32),	\
  		.ndplen_align = 8,				\
  		.dgram_item_len = 2,				\
  		.block_length = 2,				\
  		.fp_index = 2,					\
  		.reserved1 = 1,					\
  		.reserved2 = 2,					\
  		.next_fp_index = 2,				\
  	}
  
  static struct ndp_parser_opts ndp16_opts = INIT_NDP16_OPTS;
  static struct ndp_parser_opts ndp32_opts = INIT_NDP32_OPTS;
  
  static inline void put_ncm(__le16 **p, unsigned size, unsigned val)
  {
  	switch (size) {
  	case 1:
  		put_unaligned_le16((u16)val, *p);
  		break;
  	case 2:
  		put_unaligned_le32((u32)val, *p);
  
  		break;
  	default:
  		BUG();
  	}
  
  	*p += size;
  }
  
  static inline unsigned get_ncm(__le16 **p, unsigned size)
  {
  	unsigned tmp;
  
  	switch (size) {
  	case 1:
  		tmp = get_unaligned_le16(*p);
  		break;
  	case 2:
  		tmp = get_unaligned_le32(*p);
  		break;
  	default:
  		BUG();
  	}
  
  	*p += size;
  	return tmp;
  }
  
  /*-------------------------------------------------------------------------*/
  
  static inline void ncm_reset_values(struct f_ncm *ncm)
  {
  	ncm->parser_opts = &ndp16_opts;
  	ncm->is_crc = false;
  	ncm->port.cdc_filter = DEFAULT_FILTER;
  
  	/* doesn't make sense for ncm, fixed size used */
  	ncm->port.header_len = 0;
  
  	ncm->port.fixed_out_len = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize);
  	ncm->port.fixed_in_len = NTB_DEFAULT_IN_SIZE;
  }
  
  /*
   * Context: ncm->lock held
   */
  static void ncm_do_notify(struct f_ncm *ncm)
  {
  	struct usb_request		*req = ncm->notify_req;
  	struct usb_cdc_notification	*event;
  	struct usb_composite_dev	*cdev = ncm->port.func.config->cdev;
  	__le32				*data;
  	int				status;
  
  	/* notification already in flight? */
  	if (!req)
  		return;
  
  	event = req->buf;
  	switch (ncm->notify_state) {
  	case NCM_NOTIFY_NONE:
  		return;
  
  	case NCM_NOTIFY_CONNECT:
  		event->bNotificationType = USB_CDC_NOTIFY_NETWORK_CONNECTION;
  		if (ncm->is_open)
  			event->wValue = cpu_to_le16(1);
  		else
  			event->wValue = cpu_to_le16(0);
  		event->wLength = 0;
  		req->length = sizeof *event;
  
  		DBG(cdev, "notify connect %s\n",
  				ncm->is_open ? "true" : "false");
  		ncm->notify_state = NCM_NOTIFY_NONE;
  		break;
  
  	case NCM_NOTIFY_SPEED:
  		event->bNotificationType = USB_CDC_NOTIFY_SPEED_CHANGE;
  		event->wValue = cpu_to_le16(0);
  		event->wLength = cpu_to_le16(8);
  		req->length = NCM_STATUS_BYTECOUNT;
  
  		/* SPEED_CHANGE data is up/down speeds in bits/sec */
  		data = req->buf + sizeof *event;
  		data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));
  		data[1] = data[0];
  
  		DBG(cdev, "notify speed %d\n", ncm_bitrate(cdev->gadget));
  		ncm->notify_state = NCM_NOTIFY_CONNECT;
  		break;
  	}
  	event->bmRequestType = 0xA1;
  	event->wIndex = cpu_to_le16(ncm->ctrl_id);
  
  	ncm->notify_req = NULL;
  	/*
  	 * In double buffering if there is a space in FIFO,
  	 * completion callback can be called right after the call,
  	 * so unlocking
  	 */
  	spin_unlock(&ncm->lock);
  	status = usb_ep_queue(ncm->notify, req, GFP_ATOMIC);
  	spin_lock(&ncm->lock);
  	if (status < 0) {
  		ncm->notify_req = req;
  		DBG(cdev, "notify --> %d\n", status);
  	}
  }
  
  /*
   * Context: ncm->lock held
   */
  static void ncm_notify(struct f_ncm *ncm)
  {
  	/*
  	 * NOTE on most versions of Linux, host side cdc-ethernet
  	 * won't listen for notifications until its netdevice opens.
  	 * The first notification then sits in the FIFO for a long
  	 * time, and the second one is queued.
  	 *
  	 * If ncm_notify() is called before the second (CONNECT)
  	 * notification is sent, then it will reset to send the SPEED
  	 * notificaion again (and again, and again), but it's not a problem
  	 */
  	ncm->notify_state = NCM_NOTIFY_SPEED;
  	ncm_do_notify(ncm);
  }
  
  static void ncm_notify_complete(struct usb_ep *ep, struct usb_request *req)
  {
  	struct f_ncm			*ncm = req->context;
  	struct usb_composite_dev	*cdev = ncm->port.func.config->cdev;
  	struct usb_cdc_notification	*event = req->buf;
  
  	spin_lock(&ncm->lock);
  	switch (req->status) {
  	case 0:
  		VDBG(cdev, "Notification %02x sent\n",
  		     event->bNotificationType);
  		break;
  	case -ECONNRESET:
  	case -ESHUTDOWN:
  		ncm->notify_state = NCM_NOTIFY_NONE;
  		break;
  	default:
  		DBG(cdev, "event %02x --> %d\n",
  			event->bNotificationType, req->status);
  		break;
  	}
  	ncm->notify_req = req;
  	ncm_do_notify(ncm);
  	spin_unlock(&ncm->lock);
  }
  
  static void ncm_ep0out_complete(struct usb_ep *ep, struct usb_request *req)
  {
  	/* now for SET_NTB_INPUT_SIZE only */
  	unsigned		in_size;
  	struct usb_function	*f = req->context;
  	struct f_ncm		*ncm = func_to_ncm(f);
  	struct usb_composite_dev *cdev = ep->driver_data;
  
  	req->context = NULL;
  	if (req->status || req->actual != req->length) {
  		DBG(cdev, "Bad control-OUT transfer\n");
  		goto invalid;
  	}
  
  	in_size = get_unaligned_le32(req->buf);
  	if (in_size < USB_CDC_NCM_NTB_MIN_IN_SIZE ||
  	    in_size > le32_to_cpu(ntb_parameters.dwNtbInMaxSize)) {
  		DBG(cdev, "Got wrong INPUT SIZE (%d) from host\n", in_size);
  		goto invalid;
  	}
  
  	ncm->port.fixed_in_len = in_size;
  	VDBG(cdev, "Set NTB INPUT SIZE %d\n", in_size);
  	return;
  
  invalid:
  	usb_ep_set_halt(ep);
  	return;
  }
  
  static int ncm_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
  {
  	struct f_ncm		*ncm = func_to_ncm(f);
  	struct usb_composite_dev *cdev = f->config->cdev;
  	struct usb_request	*req = cdev->req;
  	int			value = -EOPNOTSUPP;
  	u16			w_index = le16_to_cpu(ctrl->wIndex);
  	u16			w_value = le16_to_cpu(ctrl->wValue);
  	u16			w_length = le16_to_cpu(ctrl->wLength);
  
  	/*
  	 * composite driver infrastructure handles everything except
  	 * CDC class messages; interface activation uses set_alt().
  	 */
  	switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
  	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  			| USB_CDC_SET_ETHERNET_PACKET_FILTER:
  		/*
  		 * see 6.2.30: no data, wIndex = interface,
  		 * wValue = packet filter bitmap
  		 */
  		if (w_length != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		DBG(cdev, "packet filter %02x\n", w_value);
  		/*
  		 * REVISIT locking of cdc_filter.  This assumes the UDC
  		 * driver won't have a concurrent packet TX irq running on
  		 * another CPU; or that if it does, this write is atomic...
  		 */
  		ncm->port.cdc_filter = w_value;
  		value = 0;
  		break;
  	/*
  	 * and optionally:
  	 * case USB_CDC_SEND_ENCAPSULATED_COMMAND:
  	 * case USB_CDC_GET_ENCAPSULATED_RESPONSE:
  	 * case USB_CDC_SET_ETHERNET_MULTICAST_FILTERS:
  	 * case USB_CDC_SET_ETHERNET_PM_PATTERN_FILTER:
  	 * case USB_CDC_GET_ETHERNET_PM_PATTERN_FILTER:
  	 * case USB_CDC_GET_ETHERNET_STATISTIC:
  	 */
  
  	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_GET_NTB_PARAMETERS:
  
  		if (w_length == 0 || w_value != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		value = w_length > sizeof ntb_parameters ?
  			sizeof ntb_parameters : w_length;
  		memcpy(req->buf, &ntb_parameters, value);
  		VDBG(cdev, "Host asked NTB parameters\n");
  		break;
  
  	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_GET_NTB_INPUT_SIZE:
  
  		if (w_length < 4 || w_value != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		put_unaligned_le32(ncm->port.fixed_in_len, req->buf);
  		value = 4;
  		VDBG(cdev, "Host asked INPUT SIZE, sending %d\n",
  		     ncm->port.fixed_in_len);
  		break;
  
  	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_SET_NTB_INPUT_SIZE:
  	{
  		if (w_length != 4 || w_value != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		req->complete = ncm_ep0out_complete;
  		req->length = w_length;
  		req->context = f;
  
  		value = req->length;
  		break;
  	}
  
  	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_GET_NTB_FORMAT:
  	{
  		uint16_t format;
  
  		if (w_length < 2 || w_value != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		format = (ncm->parser_opts == &ndp16_opts) ? 0x0000 : 0x0001;
  		put_unaligned_le16(format, req->buf);
  		value = 2;
  		VDBG(cdev, "Host asked NTB FORMAT, sending %d\n", format);
  		break;
  	}
  
  	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_SET_NTB_FORMAT:
  	{
  		if (w_length != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		switch (w_value) {
  		case 0x0000:
  			ncm->parser_opts = &ndp16_opts;
  			DBG(cdev, "NCM16 selected\n");
  			break;
  		case 0x0001:
  			ncm->parser_opts = &ndp32_opts;
  			DBG(cdev, "NCM32 selected\n");
  			break;
  		default:
  			goto invalid;
  		}
  		value = 0;
  		break;
  	}
  	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_GET_CRC_MODE:
  	{
  		uint16_t is_crc;
  
  		if (w_length < 2 || w_value != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		is_crc = ncm->is_crc ? 0x0001 : 0x0000;
  		put_unaligned_le16(is_crc, req->buf);
  		value = 2;
  		VDBG(cdev, "Host asked CRC MODE, sending %d\n", is_crc);
  		break;
  	}
  
  	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
  		| USB_CDC_SET_CRC_MODE:
  	{
  		int ndp_hdr_crc = 0;
  
  		if (w_length != 0 || w_index != ncm->ctrl_id)
  			goto invalid;
  		switch (w_value) {
  		case 0x0000:
  			ncm->is_crc = false;
  			ndp_hdr_crc = NCM_NDP_HDR_NOCRC;
  			DBG(cdev, "non-CRC mode selected\n");
  			break;
  		case 0x0001:
  			ncm->is_crc = true;
  			ndp_hdr_crc = NCM_NDP_HDR_CRC;
  			DBG(cdev, "CRC mode selected\n");
  			break;
  		default:
  			goto invalid;
  		}
  		ncm->parser_opts->ndp_sign &= ~NCM_NDP_HDR_CRC_MASK;
  		ncm->parser_opts->ndp_sign |= ndp_hdr_crc;
  		value = 0;
  		break;
  	}
  
  	/* and disabled in ncm descriptor: */
  	/* case USB_CDC_GET_NET_ADDRESS: */
  	/* case USB_CDC_SET_NET_ADDRESS: */
  	/* case USB_CDC_GET_MAX_DATAGRAM_SIZE: */
  	/* case USB_CDC_SET_MAX_DATAGRAM_SIZE: */
  
  	default:
  invalid:
  		DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
  			ctrl->bRequestType, ctrl->bRequest,
  			w_value, w_index, w_length);
  	}
  
  	/* respond with data transfer or status phase? */
  	if (value >= 0) {
  		DBG(cdev, "ncm req%02x.%02x v%04x i%04x l%d\n",
  			ctrl->bRequestType, ctrl->bRequest,
  			w_value, w_index, w_length);
  		req->zero = 0;
  		req->length = value;
  		value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
  		if (value < 0)
  			ERROR(cdev, "ncm req %02x.%02x response err %d\n",
  					ctrl->bRequestType, ctrl->bRequest,
  					value);
  	}
  
  	/* device either stalls (value < 0) or reports success */
  	return value;
  }
  
  
  static int ncm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
  {
  	struct f_ncm		*ncm = func_to_ncm(f);
  	struct usb_composite_dev *cdev = f->config->cdev;
  
  	/* Control interface has only altsetting 0 */
  	if (intf == ncm->ctrl_id) {
  		if (alt != 0)
  			goto fail;
  
  		if (ncm->notify->driver_data) {
  			DBG(cdev, "reset ncm control %d\n", intf);
  			usb_ep_disable(ncm->notify);
  		}
  
  		if (!(ncm->notify->desc)) {
  			DBG(cdev, "init ncm ctrl %d\n", intf);
  			if (config_ep_by_speed(cdev->gadget, f, ncm->notify))
  				goto fail;
  		}
  		usb_ep_enable(ncm->notify);
  		ncm->notify->driver_data = ncm;
  
  	/* Data interface has two altsettings, 0 and 1 */
  	} else if (intf == ncm->data_id) {
  		if (alt > 1)
  			goto fail;
  
  		if (ncm->port.in_ep->driver_data) {
  			DBG(cdev, "reset ncm\n");
  			gether_disconnect(&ncm->port);
  			ncm_reset_values(ncm);
  		}
  
  		/*
  		 * CDC Network only sends data in non-default altsettings.
  		 * Changing altsettings resets filters, statistics, etc.
  		 */
  		if (alt == 1) {
  			struct net_device	*net;
  
  			if (!ncm->port.in_ep->desc ||
  			    !ncm->port.out_ep->desc) {
  				DBG(cdev, "init ncm\n");
  				if (config_ep_by_speed(cdev->gadget, f,
  						       ncm->port.in_ep) ||
  				    config_ep_by_speed(cdev->gadget, f,
  						       ncm->port.out_ep)) {
  					ncm->port.in_ep->desc = NULL;
  					ncm->port.out_ep->desc = NULL;
  					goto fail;
  				}
  			}
  
  			/* TODO */
  			/* Enable zlps by default for NCM conformance;
  			 * override for musb_hdrc (avoids txdma ovhead)
  			 */
  			ncm->port.is_zlp_ok = !(
  				gadget_is_musbhdrc(cdev->gadget)
  				);
  			ncm->port.cdc_filter = DEFAULT_FILTER;
  			DBG(cdev, "activate ncm\n");
  			net = gether_connect(&ncm->port);
  			if (IS_ERR(net))
  				return PTR_ERR(net);
  		}
  
  		spin_lock(&ncm->lock);
  		ncm_notify(ncm);
  		spin_unlock(&ncm->lock);
  	} else
  		goto fail;
  
  	return 0;
  fail:
  	return -EINVAL;
  }
  
  /*
   * Because the data interface supports multiple altsettings,
   * this NCM function *MUST* implement a get_alt() method.
   */
  static int ncm_get_alt(struct usb_function *f, unsigned intf)
  {
  	struct f_ncm		*ncm = func_to_ncm(f);
  
  	if (intf == ncm->ctrl_id)
  		return 0;
  	return ncm->port.in_ep->driver_data ? 1 : 0;
  }
  
  static struct sk_buff *ncm_wrap_ntb(struct gether *port,
  				    struct sk_buff *skb)
  {
  	struct f_ncm	*ncm = func_to_ncm(&port->func);
  	struct sk_buff	*skb2;
  	int		ncb_len = 0;
  	__le16		*tmp;
  	int		div = ntb_parameters.wNdpInDivisor;
  	int		rem = ntb_parameters.wNdpInPayloadRemainder;
  	int		pad;
  	int		ndp_align = ntb_parameters.wNdpInAlignment;
  	int		ndp_pad;
  	unsigned	max_size = ncm->port.fixed_in_len;
  	struct ndp_parser_opts *opts = ncm->parser_opts;
  	unsigned	crc_len = ncm->is_crc ? sizeof(uint32_t) : 0;
  
  	ncb_len += opts->nth_size;
  	ndp_pad = ALIGN(ncb_len, ndp_align) - ncb_len;
  	ncb_len += ndp_pad;
  	ncb_len += opts->ndp_size;
  	ncb_len += 2 * 2 * opts->dgram_item_len; /* Datagram entry */
  	ncb_len += 2 * 2 * opts->dgram_item_len; /* Zero datagram entry */
  	pad = ALIGN(ncb_len, div) + rem - ncb_len;
  	ncb_len += pad;
  
  	if (ncb_len + skb->len + crc_len > max_size) {
  		dev_kfree_skb_any(skb);
  		return NULL;
  	}
  
  	skb2 = skb_copy_expand(skb, ncb_len,
  			       max_size - skb->len - ncb_len - crc_len,
  			       GFP_ATOMIC);
  	dev_kfree_skb_any(skb);
  	if (!skb2)
  		return NULL;
  
  	skb = skb2;
  
  	tmp = (void *) skb_push(skb, ncb_len);
  	memset(tmp, 0, ncb_len);
  
  	put_unaligned_le32(opts->nth_sign, tmp); /* dwSignature */
  	tmp += 2;
  	/* wHeaderLength */
  	put_unaligned_le16(opts->nth_size, tmp++);
  	tmp++; /* skip wSequence */
  	put_ncm(&tmp, opts->block_length, skb->len); /* (d)wBlockLength */
  	/* (d)wFpIndex */
  	/* the first pointer is right after the NTH + align */
  	put_ncm(&tmp, opts->fp_index, opts->nth_size + ndp_pad);
  
  	tmp = (void *)tmp + ndp_pad;
  
  	/* NDP */
  	put_unaligned_le32(opts->ndp_sign, tmp); /* dwSignature */
  	tmp += 2;
  	/* wLength */
  	put_unaligned_le16(ncb_len - opts->nth_size - pad, tmp++);
  
  	tmp += opts->reserved1;
  	tmp += opts->next_fp_index; /* skip reserved (d)wNextFpIndex */
  	tmp += opts->reserved2;
  
  	if (ncm->is_crc) {
  		uint32_t crc;
  
  		crc = ~crc32_le(~0,
  				skb->data + ncb_len,
  				skb->len - ncb_len);
  		put_unaligned_le32(crc, skb->data + skb->len);
  		skb_put(skb, crc_len);
  	}
  
  	/* (d)wDatagramIndex[0] */
  	put_ncm(&tmp, opts->dgram_item_len, ncb_len);
  	/* (d)wDatagramLength[0] */
  	put_ncm(&tmp, opts->dgram_item_len, skb->len - ncb_len);
  	/* (d)wDatagramIndex[1] and  (d)wDatagramLength[1] already zeroed */
  
  	if (skb->len > MAX_TX_NONFIXED)
  		memset(skb_put(skb, max_size - skb->len),
  		       0, max_size - skb->len);
  
  	return skb;
  }
  
  static int ncm_unwrap_ntb(struct gether *port,
  			  struct sk_buff *skb,
  			  struct sk_buff_head *list)
  {
  	struct f_ncm	*ncm = func_to_ncm(&port->func);
  	__le16		*tmp = (void *) skb->data;
  	unsigned	index, index2;
  	unsigned	dg_len, dg_len2;
  	unsigned	ndp_len;
  	struct sk_buff	*skb2;
  	int		ret = -EINVAL;
  	unsigned	max_size = le32_to_cpu(ntb_parameters.dwNtbOutMaxSize);
  	struct ndp_parser_opts *opts = ncm->parser_opts;
  	unsigned	crc_len = ncm->is_crc ? sizeof(uint32_t) : 0;
  	int		dgram_counter;
  
  	/* dwSignature */
  	if (get_unaligned_le32(tmp) != opts->nth_sign) {
  		INFO(port->func.config->cdev, "Wrong NTH SIGN, skblen %d\n",
  			skb->len);
  		print_hex_dump(KERN_INFO, "HEAD:", DUMP_PREFIX_ADDRESS, 32, 1,
  			       skb->data, 32, false);
  
  		goto err;
  	}
  	tmp += 2;
  	/* wHeaderLength */
  	if (get_unaligned_le16(tmp++) != opts->nth_size) {
  		INFO(port->func.config->cdev, "Wrong NTB headersize\n");
  		goto err;
  	}
  	tmp++; /* skip wSequence */
  
  	/* (d)wBlockLength */
  	if (get_ncm(&tmp, opts->block_length) > max_size) {
  		INFO(port->func.config->cdev, "OUT size exceeded\n");
  		goto err;
  	}
  
  	index = get_ncm(&tmp, opts->fp_index);
  	/* NCM 3.2 */
  	if (((index % 4) != 0) && (index < opts->nth_size)) {
  		INFO(port->func.config->cdev, "Bad index: %x\n",
  			index);
  		goto err;
  	}
  
  	/* walk through NDP */
  	tmp = ((void *)skb->data) + index;
  	if (get_unaligned_le32(tmp) != opts->ndp_sign) {
  		INFO(port->func.config->cdev, "Wrong NDP SIGN\n");
  		goto err;
  	}
  	tmp += 2;
  
  	ndp_len = get_unaligned_le16(tmp++);
  	/*
  	 * NCM 3.3.1
  	 * entry is 2 items
  	 * item size is 16/32 bits, opts->dgram_item_len * 2 bytes
  	 * minimal: struct usb_cdc_ncm_ndpX + normal entry + zero entry
  	 */
  	if ((ndp_len < opts->ndp_size + 2 * 2 * (opts->dgram_item_len * 2))
  	    || (ndp_len % opts->ndplen_align != 0)) {
  		INFO(port->func.config->cdev, "Bad NDP length: %x\n", ndp_len);
  		goto err;
  	}
  	tmp += opts->reserved1;
  	tmp += opts->next_fp_index; /* skip reserved (d)wNextFpIndex */
  	tmp += opts->reserved2;
  
  	ndp_len -= opts->ndp_size;
  	index2 = get_ncm(&tmp, opts->dgram_item_len);
  	dg_len2 = get_ncm(&tmp, opts->dgram_item_len);
  	dgram_counter = 0;
  
  	do {
  		index = index2;
  		dg_len = dg_len2;
  		if (dg_len < 14 + crc_len) { /* ethernet header + crc */
  			INFO(port->func.config->cdev, "Bad dgram length: %x\n",
  			     dg_len);
  			goto err;
  		}
  		if (ncm->is_crc) {
  			uint32_t crc, crc2;
  
  			crc = get_unaligned_le32(skb->data +
  						 index + dg_len - crc_len);
  			crc2 = ~crc32_le(~0,
  					 skb->data + index,
  					 dg_len - crc_len);
  			if (crc != crc2) {
  				INFO(port->func.config->cdev, "Bad CRC\n");
  				goto err;
  			}
  		}
  
  		index2 = get_ncm(&tmp, opts->dgram_item_len);
  		dg_len2 = get_ncm(&tmp, opts->dgram_item_len);
  
  		if (index2 == 0 || dg_len2 == 0) {
  			skb2 = skb;
  		} else {
  			skb2 = skb_clone(skb, GFP_ATOMIC);
  			if (skb2 == NULL)
  				goto err;
  		}
  
  		if (!skb_pull(skb2, index)) {
  			ret = -EOVERFLOW;
  			goto err;
  		}
  
  		skb_trim(skb2, dg_len - crc_len);
  		skb_queue_tail(list, skb2);
  
  		ndp_len -= 2 * (opts->dgram_item_len * 2);
  
  		dgram_counter++;
  
  		if (index2 == 0 || dg_len2 == 0)
  			break;
  	} while (ndp_len > 2 * (opts->dgram_item_len * 2)); /* zero entry */
  
  	VDBG(port->func.config->cdev,
  	     "Parsed NTB with %d frames\n", dgram_counter);
  	return 0;
  err:
  	skb_queue_purge(list);
  	dev_kfree_skb_any(skb);
  	return ret;
  }
  
  static void ncm_disable(struct usb_function *f)
  {
  	struct f_ncm		*ncm = func_to_ncm(f);
  	struct usb_composite_dev *cdev = f->config->cdev;
  
  	DBG(cdev, "ncm deactivated\n");
  
  	if (ncm->port.in_ep->driver_data)
  		gether_disconnect(&ncm->port);
  
  	if (ncm->notify->driver_data) {
  		usb_ep_disable(ncm->notify);
  		ncm->notify->driver_data = NULL;
  		ncm->notify->desc = NULL;
  	}
  }
  
  /*-------------------------------------------------------------------------*/
  
  /*
   * Callbacks let us notify the host about connect/disconnect when the
   * net device is opened or closed.
   *
   * For testing, note that link states on this side include both opened
   * and closed variants of:
   *
   *   - disconnected/unconfigured
   *   - configured but inactive (data alt 0)
   *   - configured and active (data alt 1)
   *
   * Each needs to be tested with unplug, rmmod, SET_CONFIGURATION, and
   * SET_INTERFACE (altsetting).  Remember also that "configured" doesn't
   * imply the host is actually polling the notification endpoint, and
   * likewise that "active" doesn't imply it's actually using the data
   * endpoints for traffic.
   */
  
  static void ncm_open(struct gether *geth)
  {
  	struct f_ncm		*ncm = func_to_ncm(&geth->func);
  
  	DBG(ncm->port.func.config->cdev, "%s\n", __func__);
  
  	spin_lock(&ncm->lock);
  	ncm->is_open = true;
  	ncm_notify(ncm);
  	spin_unlock(&ncm->lock);
  }
  
  static void ncm_close(struct gether *geth)
  {
  	struct f_ncm		*ncm = func_to_ncm(&geth->func);
  
  	DBG(ncm->port.func.config->cdev, "%s\n", __func__);
  
  	spin_lock(&ncm->lock);
  	ncm->is_open = false;
  	ncm_notify(ncm);
  	spin_unlock(&ncm->lock);
  }
  
  /*-------------------------------------------------------------------------*/
  
  /* ethernet function driver setup/binding */
  
  static int
  ncm_bind(struct usb_configuration *c, struct usb_function *f)
  {
  	struct usb_composite_dev *cdev = c->cdev;
  	struct f_ncm		*ncm = func_to_ncm(f);
  	int			status;
  	struct usb_ep		*ep;
  
  	/* allocate instance-specific interface IDs */
  	status = usb_interface_id(c, f);
  	if (status < 0)
  		goto fail;
  	ncm->ctrl_id = status;
  	ncm_iad_desc.bFirstInterface = status;
  
  	ncm_control_intf.bInterfaceNumber = status;
  	ncm_union_desc.bMasterInterface0 = status;
  
  	status = usb_interface_id(c, f);
  	if (status < 0)
  		goto fail;
  	ncm->data_id = status;
  
  	ncm_data_nop_intf.bInterfaceNumber = status;
  	ncm_data_intf.bInterfaceNumber = status;
  	ncm_union_desc.bSlaveInterface0 = status;
  
  	status = -ENODEV;
  
  	/* allocate instance-specific endpoints */
  	ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_in_desc);
  	if (!ep)
  		goto fail;
  	ncm->port.in_ep = ep;
  	ep->driver_data = cdev;	/* claim */
  
  	ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_out_desc);
  	if (!ep)
  		goto fail;
  	ncm->port.out_ep = ep;
  	ep->driver_data = cdev;	/* claim */
  
  	ep = usb_ep_autoconfig(cdev->gadget, &fs_ncm_notify_desc);
  	if (!ep)
  		goto fail;
  	ncm->notify = ep;
  	ep->driver_data = cdev;	/* claim */
  
  	status = -ENOMEM;
  
  	/* allocate notification request and buffer */
  	ncm->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
  	if (!ncm->notify_req)
  		goto fail;
  	ncm->notify_req->buf = kmalloc(NCM_STATUS_BYTECOUNT, GFP_KERNEL);
  	if (!ncm->notify_req->buf)
  		goto fail;
  	ncm->notify_req->context = ncm;
  	ncm->notify_req->complete = ncm_notify_complete;
  
  	/* copy descriptors, and track endpoint copies */
  	f->descriptors = usb_copy_descriptors(ncm_fs_function);
  	if (!f->descriptors)
  		goto fail;
  
  	/*
  	 * support all relevant hardware speeds... we expect that when
  	 * hardware is dual speed, all bulk-capable endpoints work at
  	 * both speeds
  	 */
  	if (gadget_is_dualspeed(c->cdev->gadget)) {
  		hs_ncm_in_desc.bEndpointAddress =
  				fs_ncm_in_desc.bEndpointAddress;
  		hs_ncm_out_desc.bEndpointAddress =
  				fs_ncm_out_desc.bEndpointAddress;
  		hs_ncm_notify_desc.bEndpointAddress =
  				fs_ncm_notify_desc.bEndpointAddress;
  
  		/* copy descriptors, and track endpoint copies */
  		f->hs_descriptors = usb_copy_descriptors(ncm_hs_function);
  		if (!f->hs_descriptors)
  			goto fail;
  	}
  
  	/*
  	 * NOTE:  all that is done without knowing or caring about
  	 * the network link ... which is unavailable to this code
  	 * until we're activated via set_alt().
  	 */
  
  	ncm->port.open = ncm_open;
  	ncm->port.close = ncm_close;
  
  	DBG(cdev, "CDC Network: %s speed IN/%s OUT/%s NOTIFY/%s\n",
  			gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
  			ncm->port.in_ep->name, ncm->port.out_ep->name,
  			ncm->notify->name);
  	return 0;
  
  fail:
  	if (f->descriptors)
  		usb_free_descriptors(f->descriptors);
  
  	if (ncm->notify_req) {
  		kfree(ncm->notify_req->buf);
  		usb_ep_free_request(ncm->notify, ncm->notify_req);
  	}
  
  	/* we might as well release our claims on endpoints */
  	if (ncm->notify)
  		ncm->notify->driver_data = NULL;
  	if (ncm->port.out_ep->desc)
  		ncm->port.out_ep->driver_data = NULL;
  	if (ncm->port.in_ep->desc)
  		ncm->port.in_ep->driver_data = NULL;
  
  	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
  
  	return status;
  }
  
  static void
  ncm_unbind(struct usb_configuration *c, struct usb_function *f)
  {
  	struct f_ncm		*ncm = func_to_ncm(f);
  
  	DBG(c->cdev, "ncm unbind\n");
  
  	if (gadget_is_dualspeed(c->cdev->gadget))
  		usb_free_descriptors(f->hs_descriptors);
  	usb_free_descriptors(f->descriptors);
  
  	kfree(ncm->notify_req->buf);
  	usb_ep_free_request(ncm->notify, ncm->notify_req);
  
  	ncm_string_defs[1].s = NULL;
  	kfree(ncm);
  }
  
  /**
   * ncm_bind_config - add CDC Network link to a configuration
   * @c: the configuration to support the network link
   * @ethaddr: a buffer in which the ethernet address of the host side
   *	side of the link was recorded
   * Context: single threaded during gadget setup
   *
   * Returns zero on success, else negative errno.
   *
   * Caller must have called @gether_setup().  Caller is also responsible
   * for calling @gether_cleanup() before module unload.
   */
  int ncm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
  {
  	struct f_ncm	*ncm;
  	int		status;
  
  	if (!can_support_ecm(c->cdev->gadget) || !ethaddr)
  		return -EINVAL;
  
  	/* maybe allocate device-global string IDs */
  	if (ncm_string_defs[0].id == 0) {
  
  		/* control interface label */
  		status = usb_string_id(c->cdev);
  		if (status < 0)
  			return status;
  		ncm_string_defs[STRING_CTRL_IDX].id = status;
  		ncm_control_intf.iInterface = status;
  
  		/* data interface label */
  		status = usb_string_id(c->cdev);
  		if (status < 0)
  			return status;
  		ncm_string_defs[NCM_STRING_DATA_IDX].id = status;
  		ncm_data_nop_intf.iInterface = status;
  		ncm_data_intf.iInterface = status;
  
  		/* MAC address */
  		status = usb_string_id(c->cdev);
  		if (status < 0)
  			return status;
  		ncm_string_defs[STRING_MAC_IDX].id = status;
  		necm_desc.iMACAddress = status;
  
  		/* IAD */
  		status = usb_string_id(c->cdev);
  		if (status < 0)
  			return status;
  		ncm_string_defs[STRING_IAD_IDX].id = status;
  		ncm_iad_desc.iFunction = status;
  	}
  
  	/* allocate and initialize one new instance */
  	ncm = kzalloc(sizeof *ncm, GFP_KERNEL);
  	if (!ncm)
  		return -ENOMEM;
  
  	/* export host's Ethernet address in CDC format */
  	snprintf(ncm->ethaddr, sizeof ncm->ethaddr,
  		"%02X%02X%02X%02X%02X%02X",
  		ethaddr[0], ethaddr[1], ethaddr[2],
  		ethaddr[3], ethaddr[4], ethaddr[5]);
  	ncm_string_defs[1].s = ncm->ethaddr;
  
  	spin_lock_init(&ncm->lock);
  	ncm_reset_values(ncm);
  	ncm->port.is_fixed = true;
  
  	ncm->port.func.name = "cdc_network";
  	ncm->port.func.strings = ncm_strings;
  	/* descriptors are per-instance copies */
  	ncm->port.func.bind = ncm_bind;
  	ncm->port.func.unbind = ncm_unbind;
  	ncm->port.func.set_alt = ncm_set_alt;
  	ncm->port.func.get_alt = ncm_get_alt;
  	ncm->port.func.setup = ncm_setup;
  	ncm->port.func.disable = ncm_disable;
  
  	ncm->port.wrap = ncm_wrap_ntb;
  	ncm->port.unwrap = ncm_unwrap_ntb;
  
  	status = usb_add_function(c, &ncm->port.func);
  	if (status) {
  		ncm_string_defs[1].s = NULL;
  		kfree(ncm);
  	}
  	return status;
  }
  