--- /dev/null
+/*
+ * f_eem.c -- USB CDC Ethernet (EEM) link function driver
+ *
+ * Copyright (C) 2003-2005,2008 David Brownell
+ * Copyright (C) 2008 Nokia Corporation
+ * Copyright (C) 2009 EF Johnson Technologies
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/etherdevice.h>
+#include <linux/crc32.h>
+
+#include "u_ether.h"
+
+#define EEM_HLEN 2
+
+/*
+ * This function is a "CDC Ethernet Emulation Model" (CDC EEM)
+ * Ethernet link.
+ */
+
+struct eem_ep_descs {
+       struct usb_endpoint_descriptor  *in;
+       struct usb_endpoint_descriptor  *out;
+};
+
+struct f_eem {
+       struct gether                   port;
+       u8                              ctrl_id;
+
+       struct eem_ep_descs             fs;
+       struct eem_ep_descs             hs;
+};
+
+static inline struct f_eem *func_to_eem(struct usb_function *f)
+{
+       return container_of(f, struct f_eem, port.func);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* interface descriptor: */
+
+static struct usb_interface_descriptor eem_intf __initdata = {
+       .bLength =              sizeof eem_intf,
+       .bDescriptorType =      USB_DT_INTERFACE,
+
+       /* .bInterfaceNumber = DYNAMIC */
+       .bNumEndpoints =        2,
+       .bInterfaceClass =      USB_CLASS_COMM,
+       .bInterfaceSubClass =   USB_CDC_SUBCLASS_EEM,
+       .bInterfaceProtocol =   USB_CDC_PROTO_EEM,
+       /* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor eem_fs_in_desc __initdata = {
+       .bLength =              USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType =      USB_DT_ENDPOINT,
+
+       .bEndpointAddress =     USB_DIR_IN,
+       .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor eem_fs_out_desc __initdata = {
+       .bLength =              USB_DT_ENDPOINT_SIZE,
+       .bDescriptorType =      USB_DT_ENDPOINT,
+
+       .bEndpointAddress =     USB_DIR_OUT,
+       .bmAttributes =         USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *eem_fs_function[] __initdata = {
+       /* CDC EEM control descriptors */
+       (struct usb_descriptor_header *) &eem_intf,
+       (struct usb_descriptor_header *) &eem_fs_in_desc,
+       (struct usb_descriptor_header *) &eem_fs_out_desc,
+       NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
+       .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 eem_hs_out_desc __initdata = {
+       .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 *eem_hs_function[] __initdata = {
+       /* CDC EEM control descriptors */
+       (struct usb_descriptor_header *) &eem_intf,
+       (struct usb_descriptor_header *) &eem_hs_in_desc,
+       (struct usb_descriptor_header *) &eem_hs_out_desc,
+       NULL,
+};
+
+/* string descriptors: */
+
+static struct usb_string eem_string_defs[] = {
+       [0].s = "CDC Ethernet Emulation Model (EEM)",
+       {  } /* end of list */
+};
+
+static struct usb_gadget_strings eem_string_table = {
+       .language =             0x0409, /* en-us */
+       .strings =              eem_string_defs,
+};
+
+static struct usb_gadget_strings *eem_strings[] = {
+       &eem_string_table,
+       NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+       struct usb_composite_dev *cdev = f->config->cdev;
+       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);
+
+       DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
+               ctrl->bRequestType, ctrl->bRequest,
+               w_value, w_index, w_length);
+
+       /* device either stalls (value < 0) or reports success */
+       return value;
+}
+
+
+static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+       struct f_eem            *eem = func_to_eem(f);
+       struct usb_composite_dev *cdev = f->config->cdev;
+       struct net_device       *net;
+
+       /* we know alt == 0, so this is an activation or a reset */
+       if (alt != 0)
+               goto fail;
+
+       if (intf == eem->ctrl_id) {
+
+               if (eem->port.in_ep->driver_data) {
+                       DBG(cdev, "reset eem\n");
+                       gether_disconnect(&eem->port);
+               }
+
+               if (!eem->port.in) {
+                       DBG(cdev, "init eem\n");
+                       eem->port.in = ep_choose(cdev->gadget,
+                                       eem->hs.in, eem->fs.in);
+                       eem->port.out = ep_choose(cdev->gadget,
+                                       eem->hs.out, eem->fs.out);
+               }
+
+               /* zlps should not occur because zero-length EEM packets
+                * will be inserted in those cases where they would occur
+                */
+               eem->port.is_zlp_ok = 1;
+               eem->port.cdc_filter = DEFAULT_FILTER;
+               DBG(cdev, "activate eem\n");
+               net = gether_connect(&eem->port);
+               if (IS_ERR(net))
+                       return PTR_ERR(net);
+       } else
+               goto fail;
+
+       return 0;
+fail:
+       return -EINVAL;
+}
+
+static void eem_disable(struct usb_function *f)
+{
+       struct f_eem            *eem = func_to_eem(f);
+       struct usb_composite_dev *cdev = f->config->cdev;
+
+       DBG(cdev, "eem deactivated\n");
+
+       if (eem->port.in_ep->driver_data)
+               gether_disconnect(&eem->port);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/* EEM function driver setup/binding */
+
+static int __init
+eem_bind(struct usb_configuration *c, struct usb_function *f)
+{
+       struct usb_composite_dev *cdev = c->cdev;
+       struct f_eem            *eem = func_to_eem(f);
+       int                     status;
+       struct usb_ep           *ep;
+
+       /* allocate instance-specific interface IDs */
+       status = usb_interface_id(c, f);
+       if (status < 0)
+               goto fail;
+       eem->ctrl_id = status;
+       eem_intf.bInterfaceNumber = status;
+
+       status = -ENODEV;
+
+       /* allocate instance-specific endpoints */
+       ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
+       if (!ep)
+               goto fail;
+       eem->port.in_ep = ep;
+       ep->driver_data = cdev; /* claim */
+
+       ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
+       if (!ep)
+               goto fail;
+       eem->port.out_ep = ep;
+       ep->driver_data = cdev; /* claim */
+
+       status = -ENOMEM;
+
+       /* copy descriptors, and track endpoint copies */
+       f->descriptors = usb_copy_descriptors(eem_fs_function);
+       if (!f->descriptors)
+               goto fail;
+
+       eem->fs.in = usb_find_endpoint(eem_fs_function,
+                       f->descriptors, &eem_fs_in_desc);
+       eem->fs.out = usb_find_endpoint(eem_fs_function,
+                       f->descriptors, &eem_fs_out_desc);
+
+       /* 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)) {
+               eem_hs_in_desc.bEndpointAddress =
+                               eem_fs_in_desc.bEndpointAddress;
+               eem_hs_out_desc.bEndpointAddress =
+                               eem_fs_out_desc.bEndpointAddress;
+
+               /* copy descriptors, and track endpoint copies */
+               f->hs_descriptors = usb_copy_descriptors(eem_hs_function);
+               if (!f->hs_descriptors)
+                       goto fail;
+
+               eem->hs.in = usb_find_endpoint(eem_hs_function,
+                               f->hs_descriptors, &eem_hs_in_desc);
+               eem->hs.out = usb_find_endpoint(eem_hs_function,
+                               f->hs_descriptors, &eem_hs_out_desc);
+       }
+
+       DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
+                       gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+                       eem->port.in_ep->name, eem->port.out_ep->name);
+       return 0;
+
+fail:
+       if (f->descriptors)
+               usb_free_descriptors(f->descriptors);
+
+       /* we might as well release our claims on endpoints */
+       if (eem->port.out)
+               eem->port.out_ep->driver_data = NULL;
+       if (eem->port.in)
+               eem->port.in_ep->driver_data = NULL;
+
+       ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
+
+       return status;
+}
+
+static void
+eem_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+       struct f_eem    *eem = func_to_eem(f);
+
+       DBG(c->cdev, "eem unbind\n");
+
+       if (gadget_is_dualspeed(c->cdev->gadget))
+               usb_free_descriptors(f->hs_descriptors);
+       usb_free_descriptors(f->descriptors);
+       kfree(eem);
+}
+
+static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
+{
+}
+
+/*
+ * Add the EEM header and ethernet checksum.
+ * We currently do not attempt to put multiple ethernet frames
+ * into a single USB transfer
+ */
+static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
+{
+       struct sk_buff  *skb2 = NULL;
+       struct usb_ep   *in = port->in_ep;
+       int             padlen = 0;
+       u16             len = skb->len;
+
+       if (!skb_cloned(skb)) {
+               int headroom = skb_headroom(skb);
+               int tailroom = skb_tailroom(skb);
+
+               /* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
+                * stick two bytes of zero-length EEM packet on the end.
+                */
+               if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
+                       padlen += 2;
+
+               if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
+                               (headroom >= EEM_HLEN))
+                       goto done;
+       }
+
+       skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
+       dev_kfree_skb_any(skb);
+       skb = skb2;
+       if (!skb)
+               return skb;
+
+done:
+       /* use the "no CRC" option */
+       put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
+
+       /* EEM packet header format:
+        * b0..13:      length of ethernet frame
+        * b14:         bmCRC (0 == sentinel CRC)
+        * b15:         bmType (0 == data)
+        */
+       len = skb->len;
+       put_unaligned_le16((len & 0x3FFF) | BIT(14), skb_push(skb, 2));
+
+       /* add a zero-length EEM packet, if needed */
+       if (padlen)
+               put_unaligned_le16(0, skb_put(skb, 2));
+
+       return skb;
+}
+
+/*
+ * Remove the EEM header.  Note that there can be many EEM packets in a single
+ * USB transfer, so we need to break them out and handle them independently.
+ */
+static int eem_unwrap(struct gether *port,
+                       struct sk_buff *skb,
+                       struct sk_buff_head *list)
+{
+       struct usb_composite_dev        *cdev = port->func.config->cdev;
+       int                             status = 0;
+
+       do {
+               struct sk_buff  *skb2;
+               u16             header;
+               u16             len = 0;
+
+               if (skb->len < EEM_HLEN) {
+                       status = -EINVAL;
+                       DBG(cdev, "invalid EEM header\n");
+                       goto error;
+               }
+
+               /* remove the EEM header */
+               header = get_unaligned_le16(skb->data);
+               skb_pull(skb, EEM_HLEN);
+
+               /* EEM packet header format:
+                * b0..14:      EEM type dependent (data or command)
+                * b15:         bmType (0 == data, 1 == command)
+                */
+               if (header & BIT(15)) {
+                       struct usb_request      *req = cdev->req;
+                       u16                     bmEEMCmd;
+
+                       /* EEM command packet format:
+                        * b0..10:      bmEEMCmdParam
+                        * b11..13:     bmEEMCmd
+                        * b14:         reserved (must be zero)
+                        * b15:         bmType (1 == command)
+                        */
+                       if (header & BIT(14))
+                               continue;
+
+                       bmEEMCmd = (header >> 11) & 0x7;
+                       switch (bmEEMCmd) {
+                       case 0: /* echo */
+                               len = header & 0x7FF;
+                               if (skb->len < len) {
+                                       status = -EOVERFLOW;
+                                       goto error;
+                               }
+
+                               skb2 = skb_clone(skb, GFP_ATOMIC);
+                               if (unlikely(!skb2)) {
+                                       DBG(cdev, "EEM echo response error\n");
+                                       goto next;
+                               }
+                               skb_trim(skb2, len);
+                               put_unaligned_le16(BIT(15) | BIT(11) | len,
+                                                       skb_push(skb2, 2));
+                               skb_copy_bits(skb, 0, req->buf, skb->len);
+                               req->length = skb->len;
+                               req->complete = eem_cmd_complete;
+                               req->zero = 1;
+                               if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
+                                       DBG(cdev, "echo response queue fail\n");
+                               break;
+
+                       case 1:  /* echo response */
+                       case 2:  /* suspend hint */
+                       case 3:  /* response hint */
+                       case 4:  /* response complete hint */
+                       case 5:  /* tickle */
+                       default: /* reserved */
+                               continue;
+                       }
+               } else {
+                       u32             crc, crc2;
+                       struct sk_buff  *skb3;
+
+                       /* check for zero-length EEM packet */
+                       if (header == 0)
+                               continue;
+
+                       /* EEM data packet format:
+                        * b0..13:      length of ethernet frame
+                        * b14:         bmCRC (0 == sentinel, 1 == calculated)
+                        * b15:         bmType (0 == data)
+                        */
+                       len = header & 0x3FFF;
+                       if ((skb->len < len)
+                                       || (len < (ETH_HLEN + ETH_FCS_LEN))) {
+                               status = -EINVAL;
+                               goto error;
+                       }
+
+                       /* validate CRC */
+                       crc = get_unaligned_le32(skb->data + len - ETH_FCS_LEN);
+                       if (header & BIT(14)) {
+                               crc = get_unaligned_le32(skb->data + len
+                                                       - ETH_FCS_LEN);
+                               crc2 = ~crc32_le(~0,
+                                               skb->data,
+                                               skb->len - ETH_FCS_LEN);
+                       } else {
+                               crc = get_unaligned_be32(skb->data + len
+                                                       - ETH_FCS_LEN);
+                               crc2 = 0xdeadbeef;
+                       }
+                       if (crc != crc2) {
+                               DBG(cdev, "invalid EEM CRC\n");
+                               goto next;
+                       }
+
+                       skb2 = skb_clone(skb, GFP_ATOMIC);
+                       if (unlikely(!skb2)) {
+                               DBG(cdev, "unable to unframe EEM packet\n");
+                               continue;
+                       }
+                       skb_trim(skb2, len - ETH_FCS_LEN);
+
+                       skb3 = skb_copy_expand(skb2,
+                                               NET_IP_ALIGN,
+                                               0,
+                                               GFP_ATOMIC);
+                       if (unlikely(!skb3)) {
+                               DBG(cdev, "unable to realign EEM packet\n");
+                               dev_kfree_skb_any(skb2);
+                               continue;
+                       }
+                       dev_kfree_skb_any(skb2);
+                       skb_queue_tail(list, skb3);
+               }
+next:
+               skb_pull(skb, len);
+       } while (skb->len);
+
+error:
+       dev_kfree_skb_any(skb);
+       return status;
+}
+
+/**
+ * eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
+ * @c: the configuration to support the network link
+ * 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 __init eem_bind_config(struct usb_configuration *c)
+{
+       struct f_eem    *eem;
+       int             status;
+
+       /* maybe allocate device-global string IDs */
+       if (eem_string_defs[0].id == 0) {
+
+               /* control interface label */
+               status = usb_string_id(c->cdev);
+               if (status < 0)
+                       return status;
+               eem_string_defs[0].id = status;
+               eem_intf.iInterface = status;
+       }
+
+       /* allocate and initialize one new instance */
+       eem = kzalloc(sizeof *eem, GFP_KERNEL);
+       if (!eem)
+               return -ENOMEM;
+
+       eem->port.cdc_filter = DEFAULT_FILTER;
+
+       eem->port.func.name = "cdc_eem";
+       eem->port.func.strings = eem_strings;
+       /* descriptors are per-instance copies */
+       eem->port.func.bind = eem_bind;
+       eem->port.func.unbind = eem_unbind;
+       eem->port.func.set_alt = eem_set_alt;
+       eem->port.func.setup = eem_setup;
+       eem->port.func.disable = eem_disable;
+       eem->port.wrap = eem_wrap;
+       eem->port.unwrap = eem_unwrap;
+       eem->port.header_len = EEM_HLEN;
+
+       status = usb_add_function(c, &eem->port.func);
+       if (status)
+               kfree(eem);
+       return status;
+}
+
 
  * one (!) network link through the USB gadget stack, normally "usb0".
  *
  * The control and data models are handled by the function driver which
- * connects to this code; such as CDC Ethernet, "CDC Subset", or RNDIS.
- * That includes all descriptor and endpoint management.
+ * connects to this code; such as CDC Ethernet (ECM or EEM),
+ * "CDC Subset", or RNDIS.  That includes all descriptor and endpoint
+ * management.
  *
  * Link level addressing is handled by this component using module
  * parameters; if no such parameters are provided, random link level
        struct list_head        tx_reqs, rx_reqs;
        atomic_t                tx_qlen;
 
+       struct sk_buff_head     rx_frames;
+
        unsigned                header_len;
-       struct sk_buff          *(*wrap)(struct sk_buff *skb);
-       int                     (*unwrap)(struct sk_buff *skb);
+       struct sk_buff          *(*wrap)(struct gether *, struct sk_buff *skb);
+       int                     (*unwrap)(struct gether *,
+                                               struct sk_buff *skb,
+                                               struct sk_buff_head *list);
 
        struct work_struct      work;
 
 
 static void rx_complete(struct usb_ep *ep, struct usb_request *req)
 {
-       struct sk_buff  *skb = req->context;
+       struct sk_buff  *skb = req->context, *skb2;
        struct eth_dev  *dev = ep->driver_data;
        int             status = req->status;
 
        /* normal completion */
        case 0:
                skb_put(skb, req->actual);
-               if (dev->unwrap)
-                       status = dev->unwrap(skb);
-               if (status < 0
-                               || ETH_HLEN > skb->len
-                               || skb->len > ETH_FRAME_LEN) {
-                       dev->net->stats.rx_errors++;
-                       dev->net->stats.rx_length_errors++;
-                       DBG(dev, "rx length %d\n", skb->len);
-                       break;
-               }
 
-               skb->protocol = eth_type_trans(skb, dev->net);
-               dev->net->stats.rx_packets++;
-               dev->net->stats.rx_bytes += skb->len;
+               if (dev->unwrap) {
+                       unsigned long   flags;
 
-               /* no buffer copies needed, unless hardware can't
-                * use skb buffers.
-                */
-               status = netif_rx(skb);
+                       spin_lock_irqsave(&dev->lock, flags);
+                       if (dev->port_usb) {
+                               status = dev->unwrap(dev->port_usb,
+                                                       skb,
+                                                       &dev->rx_frames);
+                       } else {
+                               dev_kfree_skb_any(skb);
+                               status = -ENOTCONN;
+                       }
+                       spin_unlock_irqrestore(&dev->lock, flags);
+               } else {
+                       skb_queue_tail(&dev->rx_frames, skb);
+               }
                skb = NULL;
+
+               skb2 = skb_dequeue(&dev->rx_frames);
+               while (skb2) {
+                       if (status < 0
+                                       || ETH_HLEN > skb2->len
+                                       || skb2->len > ETH_FRAME_LEN) {
+                               dev->net->stats.rx_errors++;
+                               dev->net->stats.rx_length_errors++;
+                               DBG(dev, "rx length %d\n", skb2->len);
+                               dev_kfree_skb_any(skb2);
+                               goto next_frame;
+                       }
+                       skb2->protocol = eth_type_trans(skb2, dev->net);
+                       dev->net->stats.rx_packets++;
+                       dev->net->stats.rx_bytes += skb2->len;
+
+                       /* no buffer copies needed, unless hardware can't
+                        * use skb buffers.
+                        */
+                       status = netif_rx(skb2);
+next_frame:
+                       skb2 = skb_dequeue(&dev->rx_frames);
+               }
                break;
 
        /* software-driven interface shutdown */
         * or there's not enough space for extra headers we need
         */
        if (dev->wrap) {
-               struct sk_buff  *skb_new;
+               unsigned long   flags;
 
-               skb_new = dev->wrap(skb);
-               if (!skb_new)
+               spin_lock_irqsave(&dev->lock, flags);
+               if (dev->port_usb)
+                       skb = dev->wrap(dev->port_usb, skb);
+               spin_unlock_irqrestore(&dev->lock, flags);
+               if (!skb)
                        goto drop;
 
-               dev_kfree_skb_any(skb);
-               skb = skb_new;
                length = skb->len;
        }
        req->buf = skb->data;
        }
 
        if (retval) {
+               dev_kfree_skb_any(skb);
 drop:
                dev->net->stats.tx_dropped++;
-               dev_kfree_skb_any(skb);
                spin_lock_irqsave(&dev->req_lock, flags);
                if (list_empty(&dev->tx_reqs))
                        netif_start_queue(net);
        INIT_LIST_HEAD(&dev->tx_reqs);
        INIT_LIST_HEAD(&dev->rx_reqs);
 
+       skb_queue_head_init(&dev->rx_frames);
+
        /* network device setup */
        dev->net = net;
        strcpy(net->name, "usb%d");