usb gadget: RNDIS cleanups

[mv-sheeva.git] / drivers / usb / gadget / ether.c

/*
 * ether.c -- Ethernet gadget driver, with CDC and non-CDC options
 *
 * Copyright (C) 2003-2005 David Brownell
 * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
 *
 * 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
 */

/* #define VERBOSE_DEBUG */

#include <linux/kernel.h>
#include <linux/utsname.h>
#include <linux/device.h>
#include <linux/ctype.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>

#include <linux/usb/ch9.h>
#include <linux/usb/cdc.h>
#include <linux/usb/gadget.h>

#include "gadget_chips.h"

/*-------------------------------------------------------------------------*/

/*
 * Ethernet gadget driver -- with CDC and non-CDC options
 * Builds on hardware support for a full duplex link.
 *
 * CDC Ethernet is the standard USB solution for sending Ethernet frames
 * using USB.  Real hardware tends to use the same framing protocol but look
 * different for control features.  This driver strongly prefers to use
 * this USB-IF standard as its open-systems interoperability solution;
 * most host side USB stacks (except from Microsoft) support it.
 *
 * There's some hardware that can't talk CDC.  We make that hardware
 * implement a "minimalist" vendor-agnostic CDC core:  same framing, but
 * link-level setup only requires activating the configuration.  Only the
 * endpoint descriptors, and product/vendor IDs, are relevant; no control
 * operations are available.  Linux supports it, but other host operating
 * systems may not.  (This is a subset of CDC Ethernet.)
 *
 * It turns out that if you add a few descriptors to that "CDC Subset",
 * (Windows) host side drivers from MCCI can treat it as one submode of
 * a proprietary scheme called "SAFE" ... without needing to know about
 * specific product/vendor IDs.  So we do that, making it easier to use
 * those MS-Windows drivers.  Those added descriptors make it resemble a
 * CDC MDLM device, but they don't change device behavior at all.  (See
 * MCCI Engineering report 950198 "SAFE Networking Functions".)
 *
 * A third option is also in use.  Rather than CDC Ethernet, or something
 * simpler, Microsoft pushes their own approach: RNDIS.  The published
 * RNDIS specs are ambiguous and appear to be incomplete, and are also
 * needlessly complex.
 */

#define DRIVER_DESC             "Ethernet Gadget"
#define DRIVER_VERSION          "May Day 2005"

static const char shortname [] = "ether";
static const char driver_desc [] = DRIVER_DESC;

#define RX_EXTRA        20              /* guard against rx overflows */

#include "rndis.h"

#ifndef CONFIG_USB_ETH_RNDIS
#define rndis_uninit(x)         do{}while(0)
#define rndis_deregister(c)     do{}while(0)
#define rndis_exit()            do{}while(0)
#endif

/* CDC and RNDIS support the same host-chosen outgoing packet filters. */
#define DEFAULT_FILTER  (USB_CDC_PACKET_TYPE_BROADCAST \
                        |USB_CDC_PACKET_TYPE_ALL_MULTICAST \
                        |USB_CDC_PACKET_TYPE_PROMISCUOUS \
                        |USB_CDC_PACKET_TYPE_DIRECTED)


/*-------------------------------------------------------------------------*/

struct eth_dev {
        spinlock_t              lock;
        struct usb_gadget       *gadget;
        struct usb_request      *req;           /* for control responses */
        struct usb_request      *stat_req;      /* for cdc & rndis status */

        u8                      config;
        struct usb_ep           *in_ep, *out_ep, *status_ep;
        const struct usb_endpoint_descriptor
                                *in, *out, *status;

        spinlock_t              req_lock;
        struct list_head        tx_reqs, rx_reqs;

        struct net_device       *net;
        struct net_device_stats stats;
        atomic_t                tx_qlen;

        struct work_struct      work;
        unsigned                zlp:1;
        unsigned                cdc:1;
        unsigned                rndis:1;
        unsigned                suspended:1;
        u16                     cdc_filter;
        unsigned long           todo;
#define WORK_RX_MEMORY          0
        int                     rndis_config;
        u8                      host_mac [ETH_ALEN];
};

/* This version autoconfigures as much as possible at run-time.
 *
 * It also ASSUMES a self-powered device, without remote wakeup,
 * although remote wakeup support would make sense.
 */

/*-------------------------------------------------------------------------*/

/* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */

/* Thanks to NetChip Technologies for donating this product ID.
 * It's for devices with only CDC Ethernet configurations.
 */
#define CDC_VENDOR_NUM  0x0525          /* NetChip */
#define CDC_PRODUCT_NUM 0xa4a1          /* Linux-USB Ethernet Gadget */

/* For hardware that can't talk CDC, we use the same vendor ID that
 * ARM Linux has used for ethernet-over-usb, both with sa1100 and
 * with pxa250.  We're protocol-compatible, if the host-side drivers
 * use the endpoint descriptors.  bcdDevice (version) is nonzero, so
 * drivers that need to hard-wire endpoint numbers have a hook.
 *
 * The protocol is a minimal subset of CDC Ether, which works on any bulk
 * hardware that's not deeply broken ... even on hardware that can't talk
 * RNDIS (like SA-1100, with no interrupt endpoint, or anything that
 * doesn't handle control-OUT).
 */
#define SIMPLE_VENDOR_NUM       0x049f
#define SIMPLE_PRODUCT_NUM      0x505a

/* For hardware that can talk RNDIS and either of the above protocols,
 * use this ID ... the windows INF files will know it.  Unless it's
 * used with CDC Ethernet, Linux 2.4 hosts will need updates to choose
 * the non-RNDIS configuration.
 */
#define RNDIS_VENDOR_NUM        0x0525  /* NetChip */
#define RNDIS_PRODUCT_NUM       0xa4a2  /* Ethernet/RNDIS Gadget */


/* Some systems will want different product identifers published in the
 * device descriptor, either numbers or strings or both.  These string
 * parameters are in UTF-8 (superset of ASCII's 7 bit characters).
 */

static ushort idVendor;
module_param(idVendor, ushort, S_IRUGO);
MODULE_PARM_DESC(idVendor, "USB Vendor ID");

static ushort idProduct;
module_param(idProduct, ushort, S_IRUGO);
MODULE_PARM_DESC(idProduct, "USB Product ID");

static ushort bcdDevice;
module_param(bcdDevice, ushort, S_IRUGO);
MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");

static char *iManufacturer;
module_param(iManufacturer, charp, S_IRUGO);
MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");

static char *iProduct;
module_param(iProduct, charp, S_IRUGO);
MODULE_PARM_DESC(iProduct, "USB Product string");

static char *iSerialNumber;
module_param(iSerialNumber, charp, S_IRUGO);
MODULE_PARM_DESC(iSerialNumber, "SerialNumber");

/* initial value, changed by "ifconfig usb0 hw ether xx:xx:xx:xx:xx:xx" */
static char *dev_addr;
module_param(dev_addr, charp, S_IRUGO);
MODULE_PARM_DESC(dev_addr, "Device Ethernet Address");

/* this address is invisible to ifconfig */
static char *host_addr;
module_param(host_addr, charp, S_IRUGO);
MODULE_PARM_DESC(host_addr, "Host Ethernet Address");


/*-------------------------------------------------------------------------*/

/* Include CDC support if we could run on CDC-capable hardware. */

#ifdef CONFIG_USB_GADGET_NET2280
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_DUMMY_HCD
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_GOKU
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_LH7A40X
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_MQ11XX
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_OMAP
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_N9604
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_S3C2410
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_AT91
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_MUSBHSFC
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_MUSB_HDRC
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_ATMEL_USBA
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_FSL_USB2
#define DEV_CONFIG_CDC
#endif

/* For CDC-incapable hardware, choose the simple cdc subset.
 * Anything that talks bulk (without notable bugs) can do this.
 */
#ifdef CONFIG_USB_GADGET_PXA25X
#define DEV_CONFIG_SUBSET
#endif

#ifdef CONFIG_USB_GADGET_PXA27X
#define DEV_CONFIG_SUBSET
#endif

#ifdef CONFIG_USB_GADGET_SUPERH
#define DEV_CONFIG_SUBSET
#endif

#ifdef CONFIG_USB_GADGET_SA1100
/* use non-CDC for backwards compatibility */
#define DEV_CONFIG_SUBSET
#endif

#ifdef CONFIG_USB_GADGET_M66592
#define DEV_CONFIG_CDC
#endif

#ifdef CONFIG_USB_GADGET_AMD5536UDC
#define DEV_CONFIG_CDC
#endif


/*-------------------------------------------------------------------------*/

/* "main" config is either CDC, or its simple subset */
static inline int is_cdc(struct eth_dev *dev)
{
#if     !defined(DEV_CONFIG_SUBSET)
        return 1;               /* only cdc possible */
#elif   !defined (DEV_CONFIG_CDC)
        return 0;               /* only subset possible */
#else
        return dev->cdc;        /* depends on what hardware we found */
#endif
}

/* "secondary" RNDIS config may sometimes be activated */
static inline int rndis_active(struct eth_dev *dev)
{
#ifdef  CONFIG_USB_ETH_RNDIS
        return dev->rndis;
#else
        return 0;
#endif
}

#define subset_active(dev)      (!is_cdc(dev) && !rndis_active(dev))
#define cdc_active(dev)         ( is_cdc(dev) && !rndis_active(dev))



#define DEFAULT_QLEN    2       /* double buffering by default */

/* peak bulk transfer bits-per-second */
#define HS_BPS          (13 * 512 * 8 * 1000 * 8)
#define FS_BPS          (19 *  64 * 1 * 1000 * 8)

#ifdef CONFIG_USB_GADGET_DUALSPEED
#define DEVSPEED        USB_SPEED_HIGH

static unsigned qmult = 5;
module_param (qmult, uint, S_IRUGO|S_IWUSR);


/* for dual-speed hardware, use deeper queues at highspeed */
#define qlen(gadget) \
        (DEFAULT_QLEN*((gadget->speed == USB_SPEED_HIGH) ? qmult : 1))

static inline int BITRATE(struct usb_gadget *g)
{
        return (g->speed == USB_SPEED_HIGH) ? HS_BPS : FS_BPS;
}

#else   /* full speed (low speed doesn't do bulk) */

#define qmult           1

#define DEVSPEED        USB_SPEED_FULL

#define qlen(gadget) DEFAULT_QLEN

static inline int BITRATE(struct usb_gadget *g)
{
        return FS_BPS;
}
#endif


/*-------------------------------------------------------------------------*/

#define xprintk(d,level,fmt,args...) \
        printk(level "%s: " fmt , (d)->net->name , ## args)

#ifdef DEBUG
#undef DEBUG
#define DEBUG(dev,fmt,args...) \
        xprintk(dev , KERN_DEBUG , fmt , ## args)
#else
#define DEBUG(dev,fmt,args...) \
        do { } while (0)
#endif /* DEBUG */

#ifdef VERBOSE_DEBUG
#define VDEBUG  DEBUG
#else
#define VDEBUG(dev,fmt,args...) \
        do { } while (0)
#endif /* DEBUG */

#define ERROR(dev,fmt,args...) \
        xprintk(dev , KERN_ERR , fmt , ## args)
#define WARN(dev,fmt,args...) \
        xprintk(dev , KERN_WARNING , fmt , ## args)
#define INFO(dev,fmt,args...) \
        xprintk(dev , KERN_INFO , fmt , ## args)

/*-------------------------------------------------------------------------*/

/* USB DRIVER HOOKUP (to the hardware driver, below us), mostly
 * ep0 implementation:  descriptors, config management, setup().
 * also optional class-specific notification interrupt transfer.
 */

/*
 * DESCRIPTORS ... most are static, but strings and (full) configuration
 * descriptors are built on demand.  For now we do either full CDC, or
 * our simple subset, with RNDIS as an optional second configuration.
 *
 * RNDIS includes some CDC ACM descriptors ... like CDC Ethernet.  But
 * the class descriptors match a modem (they're ignored; it's really just
 * Ethernet functionality), they don't need the NOP altsetting, and the
 * status transfer endpoint isn't optional.
 */

#define STRING_MANUFACTURER             1
#define STRING_PRODUCT                  2
#define STRING_ETHADDR                  3
#define STRING_DATA                     4
#define STRING_CONTROL                  5
#define STRING_RNDIS_CONTROL            6
#define STRING_CDC                      7
#define STRING_SUBSET                   8
#define STRING_RNDIS                    9
#define STRING_SERIALNUMBER             10

/* holds our biggest descriptor (or RNDIS response) */
#define USB_BUFSIZ      256

/*
 * This device advertises one configuration, eth_config, unless RNDIS
 * is enabled (rndis_config) on hardware supporting at least two configs.
 *
 * NOTE:  Controllers like superh_udc should probably be able to use
 * an RNDIS-only configuration.
 *
 * FIXME define some higher-powered configurations to make it easier
 * to recharge batteries ...
 */

#define DEV_CONFIG_VALUE        1       /* cdc or subset */
#define DEV_RNDIS_CONFIG_VALUE  2       /* rndis; optional */

static struct usb_device_descriptor
device_desc = {
        .bLength =              sizeof device_desc,
        .bDescriptorType =      USB_DT_DEVICE,

        .bcdUSB =               __constant_cpu_to_le16 (0x0200),

        .bDeviceClass =         USB_CLASS_COMM,
        .bDeviceSubClass =      0,
        .bDeviceProtocol =      0,

        .idVendor =             __constant_cpu_to_le16 (CDC_VENDOR_NUM),
        .idProduct =            __constant_cpu_to_le16 (CDC_PRODUCT_NUM),
        .iManufacturer =        STRING_MANUFACTURER,
        .iProduct =             STRING_PRODUCT,
        .bNumConfigurations =   1,
};

static struct usb_otg_descriptor
otg_descriptor = {
        .bLength =              sizeof otg_descriptor,
        .bDescriptorType =      USB_DT_OTG,

        .bmAttributes =         USB_OTG_SRP,
};

static struct usb_config_descriptor
eth_config = {
        .bLength =              sizeof eth_config,
        .bDescriptorType =      USB_DT_CONFIG,

        /* compute wTotalLength on the fly */
        .bNumInterfaces =       2,
        .bConfigurationValue =  DEV_CONFIG_VALUE,
        .iConfiguration =       STRING_CDC,
        .bmAttributes =         USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
        .bMaxPower =            50,
};

#ifdef  CONFIG_USB_ETH_RNDIS
static struct usb_config_descriptor
rndis_config = {
        .bLength =              sizeof rndis_config,
        .bDescriptorType =      USB_DT_CONFIG,

        /* compute wTotalLength on the fly */
        .bNumInterfaces =       2,
        .bConfigurationValue =  DEV_RNDIS_CONFIG_VALUE,
        .iConfiguration =       STRING_RNDIS,
        .bmAttributes =         USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
        .bMaxPower =            50,
};
#endif

/*
 * Compared to the simple CDC subset, the full CDC Ethernet model adds
 * three class descriptors, two interface descriptors, optional status
 * endpoint.  Both have a "data" interface and two bulk endpoints.
 * There are also differences in how control requests are handled.
 *
 * RNDIS shares a lot with CDC-Ethernet, since it's a variant of the
 * CDC-ACM (modem) spec.  Unfortunately MSFT's RNDIS driver is buggy; it
 * may hang or oops.  Since bugfixes (or accurate specs, letting Linux
 * work around those bugs) are unlikely to ever come from MSFT, you may
 * wish to avoid using RNDIS.
 *
 * MCCI offers an alternative to RNDIS if you need to connect to Windows
 * but have hardware that can't support CDC Ethernet.   We add descriptors
 * to present the CDC Subset as a (nonconformant) CDC MDLM variant called
 * "SAFE".  That borrows from both CDC Ethernet and CDC MDLM.  You can
 * get those drivers from MCCI, or bundled with various products.
 */

#ifdef  DEV_CONFIG_CDC
static struct usb_interface_descriptor
control_intf = {
        .bLength =              sizeof control_intf,
        .bDescriptorType =      USB_DT_INTERFACE,

        .bInterfaceNumber =     0,
        /* status endpoint is optional; this may be patched later */
        .bNumEndpoints =        1,
        .bInterfaceClass =      USB_CLASS_COMM,
        .bInterfaceSubClass =   USB_CDC_SUBCLASS_ETHERNET,
        .bInterfaceProtocol =   USB_CDC_PROTO_NONE,
        .iInterface =           STRING_CONTROL,
};
#endif

#ifdef  CONFIG_USB_ETH_RNDIS
static const struct usb_interface_descriptor
rndis_control_intf = {
        .bLength =              sizeof rndis_control_intf,
        .bDescriptorType =      USB_DT_INTERFACE,

        .bInterfaceNumber =     0,
        .bNumEndpoints =        1,
        .bInterfaceClass =      USB_CLASS_COMM,
        .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
        .bInterfaceProtocol =   USB_CDC_ACM_PROTO_VENDOR,
        .iInterface =           STRING_RNDIS_CONTROL,
};
#endif

static const struct usb_cdc_header_desc header_desc = {
        .bLength =              sizeof header_desc,
        .bDescriptorType =      USB_DT_CS_INTERFACE,
        .bDescriptorSubType =   USB_CDC_HEADER_TYPE,

        .bcdCDC =               __constant_cpu_to_le16 (0x0110),
};

#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)

static const struct usb_cdc_union_desc union_desc = {
        .bLength =              sizeof union_desc,
        .bDescriptorType =      USB_DT_CS_INTERFACE,
        .bDescriptorSubType =   USB_CDC_UNION_TYPE,

        .bMasterInterface0 =    0,      /* index of control interface */
        .bSlaveInterface0 =     1,      /* index of DATA interface */
};

#endif  /* CDC || RNDIS */

#ifdef  CONFIG_USB_ETH_RNDIS

static const struct usb_cdc_call_mgmt_descriptor call_mgmt_descriptor = {
        .bLength =              sizeof call_mgmt_descriptor,
        .bDescriptorType =      USB_DT_CS_INTERFACE,
        .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,

        .bmCapabilities =       0x00,
        .bDataInterface =       0x01,
};

static const struct usb_cdc_acm_descriptor acm_descriptor = {
        .bLength =              sizeof acm_descriptor,
        .bDescriptorType =      USB_DT_CS_INTERFACE,
        .bDescriptorSubType =   USB_CDC_ACM_TYPE,

        .bmCapabilities =       0x00,
};

#endif

#ifndef DEV_CONFIG_CDC

/* "SAFE" loosely follows CDC WMC MDLM, violating the spec in various
 * ways:  data endpoints live in the control interface, there's no data
 * interface, and it's not used to talk to a cell phone radio.
 */

static const struct usb_cdc_mdlm_desc mdlm_desc = {
        .bLength =              sizeof mdlm_desc,
        .bDescriptorType =      USB_DT_CS_INTERFACE,
        .bDescriptorSubType =   USB_CDC_MDLM_TYPE,

        .bcdVersion =           __constant_cpu_to_le16(0x0100),
        .bGUID = {
                0x5d, 0x34, 0xcf, 0x66, 0x11, 0x18, 0x11, 0xd6,
                0xa2, 0x1a, 0x00, 0x01, 0x02, 0xca, 0x9a, 0x7f,
        },
};

/* since "usb_cdc_mdlm_detail_desc" is a variable length structure, we
 * can't really use its struct.  All we do here is say that we're using
 * the submode of "SAFE" which directly matches the CDC Subset.
 */
static const u8 mdlm_detail_desc[] = {
        6,
        USB_DT_CS_INTERFACE,
        USB_CDC_MDLM_DETAIL_TYPE,

        0,      /* "SAFE" */
        0,      /* network control capabilities (none) */
        0,      /* network data capabilities ("raw" encapsulation) */
};

#endif

static const struct usb_cdc_ether_desc ether_desc = {
        .bLength =              sizeof ether_desc,
        .bDescriptorType =      USB_DT_CS_INTERFACE,
        .bDescriptorSubType =   USB_CDC_ETHERNET_TYPE,

        /* this descriptor actually adds value, surprise! */
        .iMACAddress =          STRING_ETHADDR,
        .bmEthernetStatistics = __constant_cpu_to_le32 (0), /* no statistics */
        .wMaxSegmentSize =      __constant_cpu_to_le16 (ETH_FRAME_LEN),
        .wNumberMCFilters =     __constant_cpu_to_le16 (0),
        .bNumberPowerFilters =  0,
};


#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)

/* include the status endpoint if we can, even where it's optional.
 * 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.
 *
 * some drivers (like Linux 2.4 cdc-ether!) "need" it to exist even
 * if they ignore the connect/disconnect notifications that real aether
 * can provide.  more advanced cdc configurations might want to support
 * encapsulated commands (vendor-specific, using control-OUT).
 *
 * RNDIS requires the status endpoint, since it uses that encapsulation
 * mechanism for its funky RPC scheme.
 */

#define LOG2_STATUS_INTERVAL_MSEC       5       /* 1 << 5 == 32 msec */
#define STATUS_BYTECOUNT                16      /* 8 byte header + data */

static struct usb_endpoint_descriptor
fs_status_desc = {
        .bLength =              USB_DT_ENDPOINT_SIZE,
        .bDescriptorType =      USB_DT_ENDPOINT,

        .bEndpointAddress =     USB_DIR_IN,
        .bmAttributes =         USB_ENDPOINT_XFER_INT,
        .wMaxPacketSize =       __constant_cpu_to_le16 (STATUS_BYTECOUNT),
        .bInterval =            1 << LOG2_STATUS_INTERVAL_MSEC,
};
#endif

#ifdef  DEV_CONFIG_CDC

/* the default data interface has no endpoints ... */

static const struct usb_interface_descriptor
data_nop_intf = {
        .bLength =              sizeof data_nop_intf,
        .bDescriptorType =      USB_DT_INTERFACE,

        .bInterfaceNumber =     1,
        .bAlternateSetting =    0,
        .bNumEndpoints =        0,
        .bInterfaceClass =      USB_CLASS_CDC_DATA,
        .bInterfaceSubClass =   0,
        .bInterfaceProtocol =   0,
};

/* ... but the "real" data interface has two bulk endpoints */

static const struct usb_interface_descriptor
data_intf = {
        .bLength =              sizeof data_intf,
        .bDescriptorType =      USB_DT_INTERFACE,

        .bInterfaceNumber =     1,
        .bAlternateSetting =    1,
        .bNumEndpoints =        2,
        .bInterfaceClass =      USB_CLASS_CDC_DATA,
        .bInterfaceSubClass =   0,
        .bInterfaceProtocol =   0,
        .iInterface =           STRING_DATA,
};

#endif

#ifdef  CONFIG_USB_ETH_RNDIS

/* RNDIS doesn't activate by changing to the "real" altsetting */

static const struct usb_interface_descriptor
rndis_data_intf = {
        .bLength =              sizeof rndis_data_intf,
        .bDescriptorType =      USB_DT_INTERFACE,

        .bInterfaceNumber =     1,
        .bAlternateSetting =    0,
        .bNumEndpoints =        2,
        .bInterfaceClass =      USB_CLASS_CDC_DATA,
        .bInterfaceSubClass =   0,
        .bInterfaceProtocol =   0,
        .iInterface =           STRING_DATA,
};

#endif

#ifdef DEV_CONFIG_SUBSET

/*
 * "Simple" CDC-subset option is a simple vendor-neutral model that most
 * full speed controllers can handle:  one interface, two bulk endpoints.
 *
 * To assist host side drivers, we fancy it up a bit, and add descriptors
 * so some host side drivers will understand it as a "SAFE" variant.
 */

static const struct usb_interface_descriptor
subset_data_intf = {
        .bLength =              sizeof subset_data_intf,
        .bDescriptorType =      USB_DT_INTERFACE,

        .bInterfaceNumber =     0,
        .bAlternateSetting =    0,
        .bNumEndpoints =        2,
        .bInterfaceClass =      USB_CLASS_COMM,
        .bInterfaceSubClass =   USB_CDC_SUBCLASS_MDLM,
        .bInterfaceProtocol =   0,
        .iInterface =           STRING_DATA,
};

#endif  /* SUBSET */


static struct usb_endpoint_descriptor
fs_source_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_sink_desc = {
        .bLength =              USB_DT_ENDPOINT_SIZE,
        .bDescriptorType =      USB_DT_ENDPOINT,

        .bEndpointAddress =     USB_DIR_OUT,
        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
};

static const struct usb_descriptor_header *fs_eth_function [11] = {
        (struct usb_descriptor_header *) &otg_descriptor,
#ifdef DEV_CONFIG_CDC
        /* "cdc" mode descriptors */
        (struct usb_descriptor_header *) &control_intf,
        (struct usb_descriptor_header *) &header_desc,
        (struct usb_descriptor_header *) &union_desc,
        (struct usb_descriptor_header *) &ether_desc,
        /* NOTE: status endpoint may need to be removed */
        (struct usb_descriptor_header *) &fs_status_desc,
        /* data interface, with altsetting */
        (struct usb_descriptor_header *) &data_nop_intf,
        (struct usb_descriptor_header *) &data_intf,
        (struct usb_descriptor_header *) &fs_source_desc,
        (struct usb_descriptor_header *) &fs_sink_desc,
        NULL,
#endif /* DEV_CONFIG_CDC */
};

static inline void __init fs_subset_descriptors(void)
{
#ifdef DEV_CONFIG_SUBSET
        /* behavior is "CDC Subset"; extra descriptors say "SAFE" */
        fs_eth_function[1] = (struct usb_descriptor_header *) &subset_data_intf;
        fs_eth_function[2] = (struct usb_descriptor_header *) &header_desc;
        fs_eth_function[3] = (struct usb_descriptor_header *) &mdlm_desc;
        fs_eth_function[4] = (struct usb_descriptor_header *) &mdlm_detail_desc;
        fs_eth_function[5] = (struct usb_descriptor_header *) &ether_desc;
        fs_eth_function[6] = (struct usb_descriptor_header *) &fs_source_desc;
        fs_eth_function[7] = (struct usb_descriptor_header *) &fs_sink_desc;
        fs_eth_function[8] = NULL;
#else
        fs_eth_function[1] = NULL;
#endif
}

#ifdef  CONFIG_USB_ETH_RNDIS
static const struct usb_descriptor_header *fs_rndis_function [] = {
        (struct usb_descriptor_header *) &otg_descriptor,
        /* control interface matches ACM, not Ethernet */
        (struct usb_descriptor_header *) &rndis_control_intf,
        (struct usb_descriptor_header *) &header_desc,
        (struct usb_descriptor_header *) &call_mgmt_descriptor,
        (struct usb_descriptor_header *) &acm_descriptor,
        (struct usb_descriptor_header *) &union_desc,
        (struct usb_descriptor_header *) &fs_status_desc,
        /* data interface has no altsetting */
        (struct usb_descriptor_header *) &rndis_data_intf,
        (struct usb_descriptor_header *) &fs_source_desc,
        (struct usb_descriptor_header *) &fs_sink_desc,
        NULL,
};
#endif

/*
 * usb 2.0 devices need to expose both high speed and full speed
 * descriptors, unless they only run at full speed.
 */

#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
static struct usb_endpoint_descriptor
hs_status_desc = {
        .bLength =              USB_DT_ENDPOINT_SIZE,
        .bDescriptorType =      USB_DT_ENDPOINT,

        .bmAttributes =         USB_ENDPOINT_XFER_INT,
        .wMaxPacketSize =       __constant_cpu_to_le16 (STATUS_BYTECOUNT),
        .bInterval =            LOG2_STATUS_INTERVAL_MSEC + 4,
};
#endif /* DEV_CONFIG_CDC */

static struct usb_endpoint_descriptor
hs_source_desc = {
        .bLength =              USB_DT_ENDPOINT_SIZE,
        .bDescriptorType =      USB_DT_ENDPOINT,

        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
        .wMaxPacketSize =       __constant_cpu_to_le16 (512),
};

static struct usb_endpoint_descriptor
hs_sink_desc = {
        .bLength =              USB_DT_ENDPOINT_SIZE,
        .bDescriptorType =      USB_DT_ENDPOINT,

        .bmAttributes =         USB_ENDPOINT_XFER_BULK,
        .wMaxPacketSize =       __constant_cpu_to_le16 (512),
};

static struct usb_qualifier_descriptor
dev_qualifier = {
        .bLength =              sizeof dev_qualifier,
        .bDescriptorType =      USB_DT_DEVICE_QUALIFIER,

        .bcdUSB =               __constant_cpu_to_le16 (0x0200),
        .bDeviceClass =         USB_CLASS_COMM,

        .bNumConfigurations =   1,
};

static const struct usb_descriptor_header *hs_eth_function [11] = {
        (struct usb_descriptor_header *) &otg_descriptor,
#ifdef DEV_CONFIG_CDC
        /* "cdc" mode descriptors */
        (struct usb_descriptor_header *) &control_intf,
        (struct usb_descriptor_header *) &header_desc,
        (struct usb_descriptor_header *) &union_desc,
        (struct usb_descriptor_header *) &ether_desc,
        /* NOTE: status endpoint may need to be removed */
        (struct usb_descriptor_header *) &hs_status_desc,
        /* data interface, with altsetting */
        (struct usb_descriptor_header *) &data_nop_intf,
        (struct usb_descriptor_header *) &data_intf,
        (struct usb_descriptor_header *) &hs_source_desc,
        (struct usb_descriptor_header *) &hs_sink_desc,
        NULL,
#endif /* DEV_CONFIG_CDC */
};

static inline void __init hs_subset_descriptors(void)
{
#ifdef DEV_CONFIG_SUBSET
        /* behavior is "CDC Subset"; extra descriptors say "SAFE" */
        hs_eth_function[1] = (struct usb_descriptor_header *) &subset_data_intf;
        hs_eth_function[2] = (struct usb_descriptor_header *) &header_desc;
        hs_eth_function[3] = (struct usb_descriptor_header *) &mdlm_desc;
        hs_eth_function[4] = (struct usb_descriptor_header *) &mdlm_detail_desc;
        hs_eth_function[5] = (struct usb_descriptor_header *) &ether_desc;
        hs_eth_function[6] = (struct usb_descriptor_header *) &hs_source_desc;
        hs_eth_function[7] = (struct usb_descriptor_header *) &hs_sink_desc;
        hs_eth_function[8] = NULL;
#else
        hs_eth_function[1] = NULL;
#endif
}

#ifdef  CONFIG_USB_ETH_RNDIS
static const struct usb_descriptor_header *hs_rndis_function [] = {
        (struct usb_descriptor_header *) &otg_descriptor,
        /* control interface matches ACM, not Ethernet */
        (struct usb_descriptor_header *) &rndis_control_intf,
        (struct usb_descriptor_header *) &header_desc,
        (struct usb_descriptor_header *) &call_mgmt_descriptor,
        (struct usb_descriptor_header *) &acm_descriptor,
        (struct usb_descriptor_header *) &union_desc,
        (struct usb_descriptor_header *) &hs_status_desc,
        /* data interface has no altsetting */
        (struct usb_descriptor_header *) &rndis_data_intf,
        (struct usb_descriptor_header *) &hs_source_desc,
        (struct usb_descriptor_header *) &hs_sink_desc,
        NULL,
};
#endif


/* maxpacket and other transfer characteristics vary by speed. */
static inline struct usb_endpoint_descriptor *
ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
                struct usb_endpoint_descriptor *fs)
{
        if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
                return hs;
        return fs;
}


/*-------------------------------------------------------------------------*/

/* descriptors that are built on-demand */

static char                             manufacturer [50];
static char                             product_desc [40] = DRIVER_DESC;
static char                             serial_number [20];

/* address that the host will use ... usually assigned at random */
static char                             ethaddr [2 * ETH_ALEN + 1];

/* static strings, in UTF-8 */
static struct usb_string                strings [] = {
        { STRING_MANUFACTURER,  manufacturer, },
        { STRING_PRODUCT,       product_desc, },
        { STRING_SERIALNUMBER,  serial_number, },
        { STRING_DATA,          "Ethernet Data", },
        { STRING_ETHADDR,       ethaddr, },
#ifdef  DEV_CONFIG_CDC
        { STRING_CDC,           "CDC Ethernet", },
        { STRING_CONTROL,       "CDC Communications Control", },
#endif
#ifdef  DEV_CONFIG_SUBSET
        { STRING_SUBSET,        "CDC Ethernet Subset", },
#endif
#ifdef  CONFIG_USB_ETH_RNDIS
        { STRING_RNDIS,         "RNDIS", },
        { STRING_RNDIS_CONTROL, "RNDIS Communications Control", },
#endif
        {  }            /* end of list */
};

static struct usb_gadget_strings        stringtab = {
        .language       = 0x0409,       /* en-us */
        .strings        = strings,
};

/*
 * one config, two interfaces:  control, data.
 * complications: class descriptors, and an altsetting.
 */
static int
config_buf(struct usb_gadget *g, u8 *buf, u8 type, unsigned index, int is_otg)
{
        int                                     len;
        const struct usb_config_descriptor      *config;
        const struct usb_descriptor_header      **function;
        int                                     hs = 0;

        if (gadget_is_dualspeed(g)) {
                hs = (g->speed == USB_SPEED_HIGH);
                if (type == USB_DT_OTHER_SPEED_CONFIG)
                        hs = !hs;
        }
#define which_fn(t)     (hs ? hs_ ## t ## _function : fs_ ## t ## _function)

        if (index >= device_desc.bNumConfigurations)
                return -EINVAL;

#ifdef  CONFIG_USB_ETH_RNDIS
        /* list the RNDIS config first, to make Microsoft's drivers
         * happy. DOCSIS 1.0 needs this too.
         */
        if (device_desc.bNumConfigurations == 2 && index == 0) {
                config = &rndis_config;
                function = which_fn (rndis);
        } else
#endif
        {
                config = &eth_config;
                function = which_fn (eth);
        }

        /* for now, don't advertise srp-only devices */
        if (!is_otg)
                function++;

        len = usb_gadget_config_buf (config, buf, USB_BUFSIZ, function);
        if (len < 0)
                return len;
        ((struct usb_config_descriptor *) buf)->bDescriptorType = type;
        return len;
}

/*-------------------------------------------------------------------------*/

static void eth_start (struct eth_dev *dev, gfp_t gfp_flags);
static int alloc_requests (struct eth_dev *dev, unsigned n, gfp_t gfp_flags);

static int
set_ether_config (struct eth_dev *dev, gfp_t gfp_flags)
{
        int                                     result = 0;
        struct usb_gadget                       *gadget = dev->gadget;

#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
        /* status endpoint used for RNDIS and (optionally) CDC */
        if (!subset_active(dev) && dev->status_ep) {
                dev->status = ep_desc (gadget, &hs_status_desc,
                                                &fs_status_desc);
                dev->status_ep->driver_data = dev;

                result = usb_ep_enable (dev->status_ep, dev->status);
                if (result != 0) {
                        DEBUG (dev, "enable %s --> %d\n",
                                dev->status_ep->name, result);
                        goto done;
                }
        }
#endif

        dev->in = ep_desc(gadget, &hs_source_desc, &fs_source_desc);
        dev->in_ep->driver_data = dev;

        dev->out = ep_desc(gadget, &hs_sink_desc, &fs_sink_desc);
        dev->out_ep->driver_data = dev;

        /* With CDC,  the host isn't allowed to use these two data
         * endpoints in the default altsetting for the interface.
         * so we don't activate them yet.  Reset from SET_INTERFACE.
         *
         * Strictly speaking RNDIS should work the same: activation is
         * a side effect of setting a packet filter.  Deactivation is
         * from REMOTE_NDIS_HALT_MSG, reset from REMOTE_NDIS_RESET_MSG.
         */
        if (!cdc_active(dev)) {
                result = usb_ep_enable (dev->in_ep, dev->in);
                if (result != 0) {
                        DEBUG(dev, "enable %s --> %d\n",
                                dev->in_ep->name, result);
                        goto done;
                }

                result = usb_ep_enable (dev->out_ep, dev->out);
                if (result != 0) {
                        DEBUG (dev, "enable %s --> %d\n",
                                dev->out_ep->name, result);
                        goto done;
                }
        }

done:
        if (result == 0)
                result = alloc_requests (dev, qlen (gadget), gfp_flags);

        /* on error, disable any endpoints  */
        if (result < 0) {
                if (!subset_active(dev) && dev->status_ep)
                        (void) usb_ep_disable (dev->status_ep);
                dev->status = NULL;
                (void) usb_ep_disable (dev->in_ep);
                (void) usb_ep_disable (dev->out_ep);
                dev->in = NULL;
                dev->out = NULL;
        }

        /* activate non-CDC configs right away
         * this isn't strictly according to the RNDIS spec
         */
        else if (!cdc_active (dev)) {
                netif_carrier_on (dev->net);
                if (netif_running (dev->net)) {
                        spin_unlock (&dev->lock);
                        eth_start (dev, GFP_ATOMIC);
                        spin_lock (&dev->lock);
                }
        }

        if (result == 0)
                DEBUG (dev, "qlen %d\n", qlen (gadget));

        /* caller is responsible for cleanup on error */
        return result;
}

static void eth_reset_config (struct eth_dev *dev)
{
        struct usb_request      *req;

        if (dev->config == 0)
                return;

        DEBUG (dev, "%s\n", __func__);

        netif_stop_queue (dev->net);
        netif_carrier_off (dev->net);

        /* RNDIS enters RNDIS_UNINITIALIZED state */
        rndis_uninit(dev->rndis_config);

        /* disable endpoints, forcing (synchronous) completion of
         * pending i/o.  then free the requests.
         */
        if (dev->in) {
                usb_ep_disable (dev->in_ep);
                spin_lock(&dev->req_lock);
                while (likely (!list_empty (&dev->tx_reqs))) {
                        req = container_of (dev->tx_reqs.next,
                                                struct usb_request, list);
                        list_del (&req->list);

                        spin_unlock(&dev->req_lock);
                        usb_ep_free_request (dev->in_ep, req);
                        spin_lock(&dev->req_lock);
                }
                spin_unlock(&dev->req_lock);
        }
        if (dev->out) {
                usb_ep_disable (dev->out_ep);
                spin_lock(&dev->req_lock);
                while (likely (!list_empty (&dev->rx_reqs))) {
                        req = container_of (dev->rx_reqs.next,
                                                struct usb_request, list);
                        list_del (&req->list);

                        spin_unlock(&dev->req_lock);
                        usb_ep_free_request (dev->out_ep, req);
                        spin_lock(&dev->req_lock);
                }
                spin_unlock(&dev->req_lock);
        }

        if (dev->status) {
                usb_ep_disable (dev->status_ep);
        }
        dev->rndis = 0;
        dev->cdc_filter = 0;
        dev->config = 0;
}

/* change our operational config.  must agree with the code
 * that returns config descriptors, and altsetting code.
 */
static int
eth_set_config (struct eth_dev *dev, unsigned number, gfp_t gfp_flags)
{
        int                     result = 0;
        struct usb_gadget       *gadget = dev->gadget;

        if (gadget_is_sa1100 (gadget)
                        && dev->config
                        && atomic_read (&dev->tx_qlen) != 0) {
                /* tx fifo is full, but we can't clear it...*/
                INFO (dev, "can't change configurations\n");
                return -ESPIPE;
        }
        eth_reset_config (dev);

        switch (number) {
        case DEV_CONFIG_VALUE:
                result = set_ether_config (dev, gfp_flags);
                break;
#ifdef  CONFIG_USB_ETH_RNDIS
        case DEV_RNDIS_CONFIG_VALUE:
                dev->rndis = 1;
                result = set_ether_config (dev, gfp_flags);
                break;
#endif
        default:
                result = -EINVAL;
                /* FALL THROUGH */
        case 0:
                break;
        }

        if (result) {
                if (number)
                        eth_reset_config (dev);
                usb_gadget_vbus_draw(dev->gadget,
                                gadget_is_otg(dev->gadget) ? 8 : 100);
        } else {
                char *speed;
                unsigned power;

                power = 2 * eth_config.bMaxPower;
                usb_gadget_vbus_draw(dev->gadget, power);

                switch (gadget->speed) {
                case USB_SPEED_FULL:    speed = "full"; break;
#ifdef CONFIG_USB_GADGET_DUALSPEED
                case USB_SPEED_HIGH:    speed = "high"; break;
#endif
                default:                speed = "?"; break;
                }

                dev->config = number;
                INFO (dev, "%s speed config #%d: %d mA, %s, using %s\n",
                                speed, number, power, driver_desc,
                                rndis_active(dev)
                                        ? "RNDIS"
                                        : (cdc_active(dev)
                                                ? "CDC Ethernet"
                                                : "CDC Ethernet Subset"));
        }
        return result;
}

/*-------------------------------------------------------------------------*/

#ifdef  DEV_CONFIG_CDC

/* The interrupt endpoint is used in CDC networking models (Ethernet, ATM)
 * only to notify the host about link status changes (which we support) or
 * report completion of some encapsulated command (as used in RNDIS).  Since
 * we want this CDC Ethernet code to be vendor-neutral, we don't use that
 * command mechanism; and only one status request is ever queued.
 */

static void eth_status_complete (struct usb_ep *ep, struct usb_request *req)
{
        struct usb_cdc_notification     *event = req->buf;
        int                             value = req->status;
        struct eth_dev                  *dev = ep->driver_data;

        /* issue the second notification if host reads the first */
        if (event->bNotificationType == USB_CDC_NOTIFY_NETWORK_CONNECTION
                        && value == 0) {
                __le32  *data = req->buf + sizeof *event;

                event->bmRequestType = 0xA1;
                event->bNotificationType = USB_CDC_NOTIFY_SPEED_CHANGE;
                event->wValue = __constant_cpu_to_le16 (0);
                event->wIndex = __constant_cpu_to_le16 (1);
                event->wLength = __constant_cpu_to_le16 (8);

                /* SPEED_CHANGE data is up/down speeds in bits/sec */
                data [0] = data [1] = cpu_to_le32 (BITRATE (dev->gadget));

                req->length = STATUS_BYTECOUNT;
                value = usb_ep_queue (ep, req, GFP_ATOMIC);
                DEBUG (dev, "send SPEED_CHANGE --> %d\n", value);
                if (value == 0)
                        return;
        } else if (value != -ECONNRESET)
                DEBUG (dev, "event %02x --> %d\n",
                        event->bNotificationType, value);
        req->context = NULL;
}

static void issue_start_status (struct eth_dev *dev)
{
        struct usb_request              *req = dev->stat_req;
        struct usb_cdc_notification     *event;
        int                             value;

        DEBUG (dev, "%s, flush old status first\n", __func__);

        /* flush old status
         *
         * FIXME ugly idiom, maybe we'd be better with just
         * a "cancel the whole queue" primitive since any
         * unlink-one primitive has way too many error modes.
         * here, we "know" toggle is already clear...
         *
         * FIXME iff req->context != null just dequeue it
         */
        usb_ep_disable (dev->status_ep);
        usb_ep_enable (dev->status_ep, dev->status);

        /* 3.8.1 says to issue first NETWORK_CONNECTION, then
         * a SPEED_CHANGE.  could be useful in some configs.
         */
        event = req->buf;
        event->bmRequestType = 0xA1;
        event->bNotificationType = USB_CDC_NOTIFY_NETWORK_CONNECTION;
        event->wValue = __constant_cpu_to_le16 (1);     /* connected */
        event->wIndex = __constant_cpu_to_le16 (1);
        event->wLength = 0;

        req->length = sizeof *event;
        req->complete = eth_status_complete;
        req->context = dev;

        value = usb_ep_queue (dev->status_ep, req, GFP_ATOMIC);
        if (value < 0)
                DEBUG (dev, "status buf queue --> %d\n", value);
}

#endif

/*-------------------------------------------------------------------------*/

static void eth_setup_complete (struct usb_ep *ep, struct usb_request *req)
{
        if (req->status || req->actual != req->length)
                DEBUG ((struct eth_dev *) ep->driver_data,
                                "setup complete --> %d, %d/%d\n",
                                req->status, req->actual, req->length);
}

#ifdef CONFIG_USB_ETH_RNDIS

static void rndis_response_complete (struct usb_ep *ep, struct usb_request *req)
{
        if (req->status || req->actual != req->length)
                DEBUG ((struct eth_dev *) ep->driver_data,
                        "rndis response complete --> %d, %d/%d\n",
                        req->status, req->actual, req->length);

        /* done sending after USB_CDC_GET_ENCAPSULATED_RESPONSE */
}

static void rndis_command_complete (struct usb_ep *ep, struct usb_request *req)
{
        struct eth_dev          *dev = ep->driver_data;
        int                     status;

        /* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
        spin_lock(&dev->lock);
        status = rndis_msg_parser (dev->rndis_config, (u8 *) req->buf);
        if (status < 0)
                ERROR(dev, "%s: rndis parse error %d\n", __func__, status);
        spin_unlock(&dev->lock);
}

#endif  /* RNDIS */

/*
 * The setup() callback implements all the ep0 functionality that's not
 * handled lower down.  CDC has a number of less-common features:
 *
 *  - two interfaces:  control, and ethernet data
 *  - Ethernet data interface has two altsettings:  default, and active
 *  - class-specific descriptors for the control interface
 *  - class-specific control requests
 */
static int
eth_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
{
        struct eth_dev          *dev = get_gadget_data (gadget);
        struct usb_request      *req = dev->req;
        int                     value = -EOPNOTSUPP;
        u16                     wIndex = le16_to_cpu(ctrl->wIndex);
        u16                     wValue = le16_to_cpu(ctrl->wValue);
        u16                     wLength = le16_to_cpu(ctrl->wLength);

        /* descriptors just go into the pre-allocated ep0 buffer,
         * while config change events may enable network traffic.
         */
        req->complete = eth_setup_complete;
        switch (ctrl->bRequest) {

        case USB_REQ_GET_DESCRIPTOR:
                if (ctrl->bRequestType != USB_DIR_IN)
                        break;
                switch (wValue >> 8) {

                case USB_DT_DEVICE:
                        value = min (wLength, (u16) sizeof device_desc);
                        memcpy (req->buf, &device_desc, value);
                        break;
                case USB_DT_DEVICE_QUALIFIER:
                        if (!gadget_is_dualspeed(gadget))
                                break;
                        value = min (wLength, (u16) sizeof dev_qualifier);
                        memcpy (req->buf, &dev_qualifier, value);
                        break;

                case USB_DT_OTHER_SPEED_CONFIG:
                        if (!gadget_is_dualspeed(gadget))
                                break;
                        // FALLTHROUGH
                case USB_DT_CONFIG:
                        value = config_buf(gadget, req->buf,
                                        wValue >> 8,
                                        wValue & 0xff,
                                        gadget_is_otg(gadget));
                        if (value >= 0)
                                value = min (wLength, (u16) value);
                        break;

                case USB_DT_STRING:
                        value = usb_gadget_get_string (&stringtab,
                                        wValue & 0xff, req->buf);
                        if (value >= 0)
                                value = min (wLength, (u16) value);
                        break;
                }
                break;

        case USB_REQ_SET_CONFIGURATION:
                if (ctrl->bRequestType != 0)
                        break;
                if (gadget->a_hnp_support)
                        DEBUG (dev, "HNP available\n");
                else if (gadget->a_alt_hnp_support)
                        DEBUG (dev, "HNP needs a different root port\n");
                spin_lock (&dev->lock);
                value = eth_set_config (dev, wValue, GFP_ATOMIC);
                spin_unlock (&dev->lock);
                break;
        case USB_REQ_GET_CONFIGURATION:
                if (ctrl->bRequestType != USB_DIR_IN)
                        break;
                *(u8 *)req->buf = dev->config;
                value = min (wLength, (u16) 1);
                break;

        case USB_REQ_SET_INTERFACE:
                if (ctrl->bRequestType != USB_RECIP_INTERFACE
                                || !dev->config
                                || wIndex > 1)
                        break;
                if (!cdc_active(dev) && wIndex != 0)
                        break;
                spin_lock (&dev->lock);

                /* PXA hardware partially handles SET_INTERFACE;
                 * we need to kluge around that interference.
                 */
                if (gadget_is_pxa (gadget)) {
                        value = eth_set_config (dev, DEV_CONFIG_VALUE,
                                                GFP_ATOMIC);
                        goto done_set_intf;
                }

#ifdef DEV_CONFIG_CDC
                switch (wIndex) {
                case 0:         /* control/master intf */
                        if (wValue != 0)
                                break;
                        if (dev->status) {
                                usb_ep_disable (dev->status_ep);
                                usb_ep_enable (dev->status_ep, dev->status);
                        }
                        value = 0;
                        break;
                case 1:         /* data intf */
                        if (wValue > 1)
                                break;
                        usb_ep_disable (dev->in_ep);
                        usb_ep_disable (dev->out_ep);

                        /* CDC requires the data transfers not be done from
                         * the default interface setting ... also, setting
                         * the non-default interface resets filters etc.
                         */
                        if (wValue == 1) {
                                if (!cdc_active (dev))
                                        break;
                                usb_ep_enable (dev->in_ep, dev->in);
                                usb_ep_enable (dev->out_ep, dev->out);
                                dev->cdc_filter = DEFAULT_FILTER;
                                netif_carrier_on (dev->net);
                                if (dev->status)
                                        issue_start_status (dev);
                                if (netif_running (dev->net)) {
                                        spin_unlock (&dev->lock);
                                        eth_start (dev, GFP_ATOMIC);
                                        spin_lock (&dev->lock);
                                }
                        } else {
                                netif_stop_queue (dev->net);
                                netif_carrier_off (dev->net);
                        }
                        value = 0;
                        break;
                }
#else
                /* FIXME this is wrong, as is the assumption that
                 * all non-PXA hardware talks real CDC ...
                 */
                dev_warn (&gadget->dev, "set_interface ignored!\n");
#endif /* DEV_CONFIG_CDC */

done_set_intf:
                spin_unlock (&dev->lock);
                break;
        case USB_REQ_GET_INTERFACE:
                if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE)
                                || !dev->config
                                || wIndex > 1)
                        break;
                if (!(cdc_active(dev) || rndis_active(dev)) && wIndex != 0)
                        break;

                /* for CDC, iff carrier is on, data interface is active. */
                if (rndis_active(dev) || wIndex != 1)
                        *(u8 *)req->buf = 0;
                else
                        *(u8 *)req->buf = netif_carrier_ok (dev->net) ? 1 : 0;
                value = min (wLength, (u16) 1);
                break;

#ifdef DEV_CONFIG_CDC
        case USB_CDC_SET_ETHERNET_PACKET_FILTER:
                /* see 6.2.30: no data, wIndex = interface,
                 * wValue = packet filter bitmap
                 */
                if (ctrl->bRequestType != (USB_TYPE_CLASS|USB_RECIP_INTERFACE)
                                || !cdc_active(dev)
                                || wLength != 0
                                || wIndex > 1)
                        break;
                DEBUG (dev, "packet filter %02x\n", wValue);
                dev->cdc_filter = wValue;
                value = 0;
                break;

        /* and potentially:
         * 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:
         */

#endif /* DEV_CONFIG_CDC */

#ifdef CONFIG_USB_ETH_RNDIS
        /* RNDIS uses the CDC command encapsulation mechanism to implement
         * an RPC scheme, with much getting/setting of attributes by OID.
         */
        case USB_CDC_SEND_ENCAPSULATED_COMMAND:
                if (ctrl->bRequestType != (USB_TYPE_CLASS|USB_RECIP_INTERFACE)
                                || !rndis_active(dev)
                                || wLength > USB_BUFSIZ
                                || wValue
                                || rndis_control_intf.bInterfaceNumber
                                        != wIndex)
                        break;
                /* read the request, then process it */
                value = wLength;
                req->complete = rndis_command_complete;
                /* later, rndis_control_ack () sends a notification */
                break;

        case USB_CDC_GET_ENCAPSULATED_RESPONSE:
                if ((USB_DIR_IN|USB_TYPE_CLASS|USB_RECIP_INTERFACE)
                                        == ctrl->bRequestType
                                && rndis_active(dev)
                                // && wLength >= 0x0400
                                && !wValue
                                && rndis_control_intf.bInterfaceNumber
                                        == wIndex) {
                        u8 *buf;
                        u32 n;

                        /* return the result */
                        buf = rndis_get_next_response(dev->rndis_config, &n);
                        if (buf) {
                                memcpy(req->buf, buf, n);
                                req->complete = rndis_response_complete;
                                rndis_free_response(dev->rndis_config, buf);
                                value = n;
                        }
                        /* else stalls ... spec says to avoid that */
                }
                break;
#endif  /* RNDIS */

        default:
                VDEBUG (dev,
                        "unknown control req%02x.%02x v%04x i%04x l%d\n",
                        ctrl->bRequestType, ctrl->bRequest,
                        wValue, wIndex, wLength);
        }

        /* respond with data transfer before status phase? */
        if (value >= 0) {
                req->length = value;
                req->zero = value < wLength
                                && (value % gadget->ep0->maxpacket) == 0;
                value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
                if (value < 0) {
                        DEBUG (dev, "ep_queue --> %d\n", value);
                        req->status = 0;
                        eth_setup_complete (gadget->ep0, req);
                }
        }

        /* host either stalls (value < 0) or reports success */
        return value;
}

static void
eth_disconnect (struct usb_gadget *gadget)
{
        struct eth_dev          *dev = get_gadget_data (gadget);
        unsigned long           flags;

        spin_lock_irqsave (&dev->lock, flags);
        netif_stop_queue (dev->net);
        netif_carrier_off (dev->net);
        eth_reset_config (dev);
        spin_unlock_irqrestore (&dev->lock, flags);

        /* next we may get setup() calls to enumerate new connections;
         * or an unbind() during shutdown (including removing module).
         */
}

/*-------------------------------------------------------------------------*/

/* NETWORK DRIVER HOOKUP (to the layer above this driver) */

static int eth_change_mtu (struct net_device *net, int new_mtu)
{
        struct eth_dev  *dev = netdev_priv(net);

        if (dev->rndis)
                return -EBUSY;

        if (new_mtu <= ETH_HLEN || new_mtu > ETH_FRAME_LEN)
                return -ERANGE;
        /* no zero-length packet read wanted after mtu-sized packets */
        if (((new_mtu + sizeof (struct ethhdr)) % dev->in_ep->maxpacket) == 0)
                return -EDOM;
        net->mtu = new_mtu;
        return 0;
}

static struct net_device_stats *eth_get_stats (struct net_device *net)
{
        return &((struct eth_dev *)netdev_priv(net))->stats;
}

static void eth_get_drvinfo(struct net_device *net, struct ethtool_drvinfo *p)
{
        struct eth_dev  *dev = netdev_priv(net);
        strlcpy(p->driver, shortname, sizeof p->driver);
        strlcpy(p->version, DRIVER_VERSION, sizeof p->version);
        strlcpy(p->fw_version, dev->gadget->name, sizeof p->fw_version);
        strlcpy (p->bus_info, dev_name(&dev->gadget->dev), sizeof p->bus_info);
}

static u32 eth_get_link(struct net_device *net)
{
        struct eth_dev  *dev = netdev_priv(net);
        return dev->gadget->speed != USB_SPEED_UNKNOWN;
}

static struct ethtool_ops ops = {
        .get_drvinfo = eth_get_drvinfo,
        .get_link = eth_get_link
};

static void defer_kevent (struct eth_dev *dev, int flag)
{
        if (test_and_set_bit (flag, &dev->todo))
                return;
        if (!schedule_work (&dev->work))
                ERROR (dev, "kevent %d may have been dropped\n", flag);
        else
                DEBUG (dev, "kevent %d scheduled\n", flag);
}

static void rx_complete (struct usb_ep *ep, struct usb_request *req);

static int
rx_submit (struct eth_dev *dev, struct usb_request *req, gfp_t gfp_flags)
{
        struct sk_buff          *skb;
        int                     retval = -ENOMEM;
        size_t                  size;

        /* Padding up to RX_EXTRA handles minor disagreements with host.
         * Normally we use the USB "terminate on short read" convention;
         * so allow up to (N*maxpacket), since that memory is normally
         * already allocated.  Some hardware doesn't deal well with short
         * reads (e.g. DMA must be N*maxpacket), so for now don't trim a
         * byte off the end (to force hardware errors on overflow).
         *
         * RNDIS uses internal framing, and explicitly allows senders to
         * pad to end-of-packet.  That's potentially nice for speed,
         * but means receivers can't recover synch on their own.
         */
        size = (sizeof (struct ethhdr) + dev->net->mtu + RX_EXTRA);
        size += dev->out_ep->maxpacket - 1;
        if (rndis_active(dev))
                size += sizeof (struct rndis_packet_msg_type);
        size -= size % dev->out_ep->maxpacket;

        skb = alloc_skb(size + NET_IP_ALIGN, gfp_flags);
        if (skb == NULL) {
                DEBUG (dev, "no rx skb\n");
                goto enomem;
        }

        /* Some platforms perform better when IP packets are aligned,
         * but on at least one, checksumming fails otherwise.  Note:
         * RNDIS headers involve variable numbers of LE32 values.
         */
        skb_reserve(skb, NET_IP_ALIGN);

        req->buf = skb->data;
        req->length = size;
        req->complete = rx_complete;
        req->context = skb;

        retval = usb_ep_queue (dev->out_ep, req, gfp_flags);
        if (retval == -ENOMEM)
enomem:
                defer_kevent (dev, WORK_RX_MEMORY);
        if (retval) {
                DEBUG (dev, "rx submit --> %d\n", retval);
                if (skb)
                        dev_kfree_skb_any(skb);
                spin_lock(&dev->req_lock);
                list_add (&req->list, &dev->rx_reqs);
                spin_unlock(&dev->req_lock);
        }
        return retval;
}

static void rx_complete (struct usb_ep *ep, struct usb_request *req)
{
        struct sk_buff  *skb = req->context;
        struct eth_dev  *dev = ep->driver_data;
        int             status = req->status;

        switch (status) {

        /* normal completion */
        case 0:
                skb_put (skb, req->actual);
                /* we know MaxPacketsPerTransfer == 1 here */
                if (rndis_active(dev))
                        status = rndis_rm_hdr (skb);
                if (status < 0
                                || ETH_HLEN > skb->len
                                || skb->len > ETH_FRAME_LEN) {
                        dev->stats.rx_errors++;
                        dev->stats.rx_length_errors++;
                        DEBUG (dev, "rx length %d\n", skb->len);
                        break;
                }

                skb->protocol = eth_type_trans (skb, dev->net);
                dev->stats.rx_packets++;
                dev->stats.rx_bytes += skb->len;

                /* no buffer copies needed, unless hardware can't
                 * use skb buffers.
                 */
                status = netif_rx (skb);
                skb = NULL;
                break;

        /* software-driven interface shutdown */
        case -ECONNRESET:               // unlink
        case -ESHUTDOWN:                // disconnect etc
                VDEBUG (dev, "rx shutdown, code %d\n", status);
                goto quiesce;

        /* for hardware automagic (such as pxa) */
        case -ECONNABORTED:             // endpoint reset
                DEBUG (dev, "rx %s reset\n", ep->name);
                defer_kevent (dev, WORK_RX_MEMORY);
quiesce:
                dev_kfree_skb_any (skb);
                goto clean;

        /* data overrun */
        case -EOVERFLOW:
                dev->stats.rx_over_errors++;
                // FALLTHROUGH

        default:
                dev->stats.rx_errors++;
                DEBUG (dev, "rx status %d\n", status);
                break;
        }

        if (skb)
                dev_kfree_skb_any (skb);
        if (!netif_running (dev->net)) {
clean:
                spin_lock(&dev->req_lock);
                list_add (&req->list, &dev->rx_reqs);
                spin_unlock(&dev->req_lock);
                req = NULL;
        }
        if (req)
                rx_submit (dev, req, GFP_ATOMIC);
}

static int prealloc (struct list_head *list, struct usb_ep *ep,
                        unsigned n, gfp_t gfp_flags)
{
        unsigned                i;
        struct usb_request      *req;

        if (!n)
                return -ENOMEM;

        /* queue/recycle up to N requests */
        i = n;
        list_for_each_entry (req, list, list) {
                if (i-- == 0)
                        goto extra;
        }
        while (i--) {
                req = usb_ep_alloc_request (ep, gfp_flags);
                if (!req)
                        return list_empty (list) ? -ENOMEM : 0;
                list_add (&req->list, list);
        }
        return 0;

extra:
        /* free extras */
        for (;;) {
                struct list_head        *next;

                next = req->list.next;
                list_del (&req->list);
                usb_ep_free_request (ep, req);

                if (next == list)
                        break;

                req = container_of (next, struct usb_request, list);
        }
        return 0;
}

static int alloc_requests (struct eth_dev *dev, unsigned n, gfp_t gfp_flags)
{
        int status;

        spin_lock(&dev->req_lock);
        status = prealloc (&dev->tx_reqs, dev->in_ep, n, gfp_flags);
        if (status < 0)
                goto fail;
        status = prealloc (&dev->rx_reqs, dev->out_ep, n, gfp_flags);
        if (status < 0)
                goto fail;
        goto done;
fail:
        DEBUG (dev, "can't alloc requests\n");
done:
        spin_unlock(&dev->req_lock);
        return status;
}

static void rx_fill (struct eth_dev *dev, gfp_t gfp_flags)
{
        struct usb_request      *req;
        unsigned long           flags;

        /* fill unused rxq slots with some skb */
        spin_lock_irqsave(&dev->req_lock, flags);
        while (!list_empty (&dev->rx_reqs)) {
                req = container_of (dev->rx_reqs.next,
                                struct usb_request, list);
                list_del_init (&req->list);
                spin_unlock_irqrestore(&dev->req_lock, flags);

                if (rx_submit (dev, req, gfp_flags) < 0) {
                        defer_kevent (dev, WORK_RX_MEMORY);
                        return;
                }

                spin_lock_irqsave(&dev->req_lock, flags);
        }
        spin_unlock_irqrestore(&dev->req_lock, flags);
}

static void eth_work (struct work_struct *work)
{
        struct eth_dev  *dev = container_of(work, struct eth_dev, work);

        if (test_and_clear_bit (WORK_RX_MEMORY, &dev->todo)) {
                if (netif_running (dev->net))
                        rx_fill (dev, GFP_KERNEL);
        }

        if (dev->todo)
                DEBUG (dev, "work done, flags = 0x%lx\n", dev->todo);
}

static void tx_complete (struct usb_ep *ep, struct usb_request *req)
{
        struct sk_buff  *skb = req->context;
        struct eth_dev  *dev = ep->driver_data;

        switch (req->status) {
        default:
                dev->stats.tx_errors++;
                VDEBUG (dev, "tx err %d\n", req->status);
                /* FALLTHROUGH */
        case -ECONNRESET:               // unlink
        case -ESHUTDOWN:                // disconnect etc
                break;
        case 0:
                dev->stats.tx_bytes += skb->len;
        }
        dev->stats.tx_packets++;

        spin_lock(&dev->req_lock);
        list_add (&req->list, &dev->tx_reqs);
        spin_unlock(&dev->req_lock);
        dev_kfree_skb_any (skb);

        atomic_dec (&dev->tx_qlen);
        if (netif_carrier_ok (dev->net))
                netif_wake_queue (dev->net);
}

static inline int eth_is_promisc (struct eth_dev *dev)
{
        /* no filters for the CDC subset; always promisc */
        if (subset_active (dev))
                return 1;
        return dev->cdc_filter & USB_CDC_PACKET_TYPE_PROMISCUOUS;
}

static int eth_start_xmit (struct sk_buff *skb, struct net_device *net)
{
        struct eth_dev          *dev = netdev_priv(net);
        int                     length = skb->len;
        int                     retval;
        struct usb_request      *req = NULL;
        unsigned long           flags;

        /* apply outgoing CDC or RNDIS filters */
        if (!eth_is_promisc (dev)) {
                u8              *dest = skb->data;

                if (is_multicast_ether_addr(dest)) {
                        u16     type;

                        /* ignores USB_CDC_PACKET_TYPE_MULTICAST and host
                         * SET_ETHERNET_MULTICAST_FILTERS requests
                         */
                        if (is_broadcast_ether_addr(dest))
                                type = USB_CDC_PACKET_TYPE_BROADCAST;
                        else
                                type = USB_CDC_PACKET_TYPE_ALL_MULTICAST;
                        if (!(dev->cdc_filter & type)) {
                                dev_kfree_skb_any (skb);
                                return 0;
                        }
                }
                /* ignores USB_CDC_PACKET_TYPE_DIRECTED */
        }

        spin_lock_irqsave(&dev->req_lock, flags);
        /*
         * this freelist can be empty if an interrupt triggered disconnect()
         * and reconfigured the gadget (shutting down this queue) after the
         * network stack decided to xmit but before we got the spinlock.
         */
        if (list_empty(&dev->tx_reqs)) {
                spin_unlock_irqrestore(&dev->req_lock, flags);
                return 1;
        }

        req = container_of (dev->tx_reqs.next, struct usb_request, list);
        list_del (&req->list);

        /* temporarily stop TX queue when the freelist empties */
        if (list_empty (&dev->tx_reqs))
                netif_stop_queue (net);
        spin_unlock_irqrestore(&dev->req_lock, flags);

        /* no buffer copies needed, unless the network stack did it
         * or the hardware can't use skb buffers.
         * or there's not enough space for any RNDIS headers we need
         */
        if (rndis_active(dev)) {
                struct sk_buff  *skb_rndis;

                skb_rndis = skb_realloc_headroom (skb,
                                sizeof (struct rndis_packet_msg_type));
                if (!skb_rndis)
                        goto drop;

                dev_kfree_skb_any (skb);
                skb = skb_rndis;
                rndis_add_hdr (skb);
                length = skb->len;
        }
        req->buf = skb->data;
        req->context = skb;
        req->complete = tx_complete;

        /* use zlp framing on tx for strict CDC-Ether conformance,
         * though any robust network rx path ignores extra padding.
         * and some hardware doesn't like to write zlps.
         */
        req->zero = 1;
        if (!dev->zlp && (length % dev->in_ep->maxpacket) == 0)
                length++;

        req->length = length;

        /* throttle highspeed IRQ rate back slightly */
        if (gadget_is_dualspeed(dev->gadget))
                req->no_interrupt = (dev->gadget->speed == USB_SPEED_HIGH)
                        ? ((atomic_read(&dev->tx_qlen) % qmult) != 0)
                        : 0;

        retval = usb_ep_queue (dev->in_ep, req, GFP_ATOMIC);
        switch (retval) {
        default:
                DEBUG (dev, "tx queue err %d\n", retval);
                break;
        case 0:
                net->trans_start = jiffies;
                atomic_inc (&dev->tx_qlen);
        }

        if (retval) {
drop:
                dev->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);
                list_add (&req->list, &dev->tx_reqs);
                spin_unlock_irqrestore(&dev->req_lock, flags);
        }
        return 0;
}

/*-------------------------------------------------------------------------*/

#ifdef CONFIG_USB_ETH_RNDIS

/* The interrupt endpoint is used in RNDIS to notify the host when messages
 * other than data packets are available ... notably the REMOTE_NDIS_*_CMPLT
 * messages, but also REMOTE_NDIS_INDICATE_STATUS_MSG and potentially even
 * REMOTE_NDIS_KEEPALIVE_MSG.
 *
 * The RNDIS control queue is processed by GET_ENCAPSULATED_RESPONSE, and
 * normally just one notification will be queued.
 */

static struct usb_request *eth_req_alloc (struct usb_ep *, unsigned, gfp_t);
static void eth_req_free (struct usb_ep *ep, struct usb_request *req);

static void
rndis_control_ack_complete (struct usb_ep *ep, struct usb_request *req)
{
        struct eth_dev          *dev = ep->driver_data;

        if (req->status || req->actual != req->length)
                DEBUG (dev,
                        "rndis control ack complete --> %d, %d/%d\n",
                        req->status, req->actual, req->length);
        req->context = NULL;

        if (req != dev->stat_req)
                eth_req_free(ep, req);
}

static void rndis_resp_avail(void *_dev)
{
        struct eth_dev          *dev = _dev;
        int                     length;
        struct usb_request      *resp = dev->stat_req;

        /* in case RNDIS calls this after disconnect */
        if (!dev->status) {
                DEBUG (dev, "status ENODEV\n");
                return;
        }

        /* in case queue length > 1 */
        if (resp->context) {
                resp = eth_req_alloc (dev->status_ep, 8, GFP_ATOMIC);
                if (!resp)
                        return;
        }

        /* Send RNDIS RESPONSE_AVAILABLE notification;
         * USB_CDC_NOTIFY_RESPONSE_AVAILABLE should work too
         */
        resp->length = 8;
        resp->complete = rndis_control_ack_complete;
        resp->context = dev;

        *((__le32 *) resp->buf) = __constant_cpu_to_le32 (1);
        *((__le32 *) resp->buf + 1) = __constant_cpu_to_le32 (0);

        length = usb_ep_queue (dev->status_ep, resp, GFP_ATOMIC);
        if (length < 0) {
                resp->status = 0;
                rndis_control_ack_complete (dev->status_ep, resp);
        }
}

#else

#define rndis_resp_avail        NULL

#endif  /* RNDIS */

static void eth_start (struct eth_dev *dev, gfp_t gfp_flags)
{
        DEBUG (dev, "%s\n", __func__);

        /* fill the rx queue */
        rx_fill (dev, gfp_flags);

        /* and open the tx floodgates */
        atomic_set (&dev->tx_qlen, 0);
        netif_wake_queue (dev->net);
        if (rndis_active(dev)) {
                rndis_set_param_medium (dev->rndis_config,
                                        NDIS_MEDIUM_802_3,
                                        BITRATE(dev->gadget)/100);
                (void) rndis_signal_connect (dev->rndis_config);
        }
}

static int eth_open (struct net_device *net)
{
        struct eth_dev          *dev = netdev_priv(net);

        DEBUG (dev, "%s\n", __func__);
        if (netif_carrier_ok (dev->net))
                eth_start (dev, GFP_KERNEL);
        return 0;
}

static int eth_stop (struct net_device *net)
{
        struct eth_dev          *dev = netdev_priv(net);

        VDEBUG (dev, "%s\n", __func__);
        netif_stop_queue (net);

        DEBUG (dev, "stop stats: rx/tx %ld/%ld, errs %ld/%ld\n",
                dev->stats.rx_packets, dev->stats.tx_packets,
                dev->stats.rx_errors, dev->stats.tx_errors
                );

        /* ensure there are no more active requests */
        if (dev->config) {
                usb_ep_disable (dev->in_ep);
                usb_ep_disable (dev->out_ep);
                if (netif_carrier_ok (dev->net)) {
                        DEBUG (dev, "host still using in/out endpoints\n");
                        // FIXME idiom may leave toggle wrong here
                        usb_ep_enable (dev->in_ep, dev->in);
                        usb_ep_enable (dev->out_ep, dev->out);
                }
                if (dev->status_ep) {
                        usb_ep_disable (dev->status_ep);
                        usb_ep_enable (dev->status_ep, dev->status);
                }
        }

        if (rndis_active(dev)) {
                rndis_set_param_medium(dev->rndis_config, NDIS_MEDIUM_802_3, 0);
                (void) rndis_signal_disconnect (dev->rndis_config);
        }

        return 0;
}

/*-------------------------------------------------------------------------*/

static struct usb_request *
eth_req_alloc (struct usb_ep *ep, unsigned size, gfp_t gfp_flags)
{
        struct usb_request      *req;

        req = usb_ep_alloc_request (ep, gfp_flags);
        if (!req)
                return NULL;

        req->buf = kmalloc (size, gfp_flags);
        if (!req->buf) {
                usb_ep_free_request (ep, req);
                req = NULL;
        }
        return req;
}

static void
eth_req_free (struct usb_ep *ep, struct usb_request *req)
{
        kfree (req->buf);
        usb_ep_free_request (ep, req);
}


static void /* __init_or_exit */
eth_unbind (struct usb_gadget *gadget)
{
        struct eth_dev          *dev = get_gadget_data (gadget);

        DEBUG (dev, "unbind\n");
        rndis_deregister (dev->rndis_config);
        rndis_exit ();

        /* we've already been disconnected ... no i/o is active */
        if (dev->req) {
                eth_req_free (gadget->ep0, dev->req);
                dev->req = NULL;
        }
        if (dev->stat_req) {
                eth_req_free (dev->status_ep, dev->stat_req);
                dev->stat_req = NULL;
        }

        unregister_netdev (dev->net);
        free_netdev(dev->net);

        /* assuming we used keventd, it must quiesce too */
        flush_scheduled_work ();
        set_gadget_data (gadget, NULL);
}

static u8 __init nibble (unsigned char c)
{
        if (likely (isdigit (c)))
                return c - '0';
        c = toupper (c);
        if (likely (isxdigit (c)))
                return 10 + c - 'A';
        return 0;
}

static int __init get_ether_addr(const char *str, u8 *dev_addr)
{
        if (str) {
                unsigned        i;

                for (i = 0; i < 6; i++) {
                        unsigned char num;

                        if((*str == '.') || (*str == ':'))
                                str++;
                        num = nibble(*str++) << 4;
                        num |= (nibble(*str++));
                        dev_addr [i] = num;
                }
                if (is_valid_ether_addr (dev_addr))
                        return 0;
        }
        random_ether_addr(dev_addr);
        return 1;
}

static int __init
eth_bind (struct usb_gadget *gadget)
{
        struct eth_dev          *dev;
        struct net_device       *net;
        u8                      cdc = 1, zlp = 1, rndis = 1;
        struct usb_ep           *in_ep, *out_ep, *status_ep = NULL;
        int                     status = -ENOMEM;
        int                     gcnum;

        /* these flags are only ever cleared; compiler take note */
#ifndef DEV_CONFIG_CDC
        cdc = 0;
#endif
#ifndef CONFIG_USB_ETH_RNDIS
        rndis = 0;
#endif

        /* Because most host side USB stacks handle CDC Ethernet, that
         * standard protocol is _strongly_ preferred for interop purposes.
         * (By everyone except Microsoft.)
         */
        if (gadget_is_pxa (gadget)) {
                /* pxa doesn't support altsettings */
                cdc = 0;
        } else if (gadget_is_musbhdrc(gadget)) {
                /* reduce tx dma overhead by avoiding special cases */
                zlp = 0;
        } else if (gadget_is_sh(gadget)) {
                /* sh doesn't support multiple interfaces or configs */
                cdc = 0;
                rndis = 0;
        } else if (gadget_is_sa1100 (gadget)) {
                /* hardware can't write zlps */
                zlp = 0;
                /* sa1100 CAN do CDC, without status endpoint ... we use
                 * non-CDC to be compatible with ARM Linux-2.4 "usb-eth".
                 */
                cdc = 0;
        }

        gcnum = usb_gadget_controller_number (gadget);
        if (gcnum >= 0)
                device_desc.bcdDevice = cpu_to_le16 (0x0200 + gcnum);
        else {
                /* can't assume CDC works.  don't want to default to
                 * anything less functional on CDC-capable hardware,
                 * so we fail in this case.
                 */
                dev_err (&gadget->dev,
                        "controller '%s' not recognized\n",
                        gadget->name);
                return -ENODEV;
        }
        snprintf (manufacturer, sizeof manufacturer, "%s %s/%s",
                init_utsname()->sysname, init_utsname()->release,
                gadget->name);

        /* If there's an RNDIS configuration, that's what Windows wants to
         * be using ... so use these product IDs here and in the "linux.inf"
         * needed to install MSFT drivers.  Current Linux kernels will use
         * the second configuration if it's CDC Ethernet, and need some help
         * to choose the right configuration otherwise.
         */
        if (rndis) {
                device_desc.idVendor =
                        __constant_cpu_to_le16(RNDIS_VENDOR_NUM);
                device_desc.idProduct =
                        __constant_cpu_to_le16(RNDIS_PRODUCT_NUM);
                snprintf (product_desc, sizeof product_desc,
                        "RNDIS/%s", driver_desc);

        /* CDC subset ... recognized by Linux since 2.4.10, but Windows
         * drivers aren't widely available.  (That may be improved by
         * supporting one submode of the "SAFE" variant of MDLM.)
         */
        } else if (!cdc) {
                device_desc.idVendor =
                        __constant_cpu_to_le16(SIMPLE_VENDOR_NUM);
                device_desc.idProduct =
                        __constant_cpu_to_le16(SIMPLE_PRODUCT_NUM);
        }

        /* support optional vendor/distro customization */
        if (idVendor) {
                if (!idProduct) {
                        dev_err (&gadget->dev, "idVendor needs idProduct!\n");
                        return -ENODEV;
                }
                device_desc.idVendor = cpu_to_le16(idVendor);
                device_desc.idProduct = cpu_to_le16(idProduct);
                if (bcdDevice)
                        device_desc.bcdDevice = cpu_to_le16(bcdDevice);
        }
        if (iManufacturer)
                strlcpy (manufacturer, iManufacturer, sizeof manufacturer);
        if (iProduct)
                strlcpy (product_desc, iProduct, sizeof product_desc);
        if (iSerialNumber) {
                device_desc.iSerialNumber = STRING_SERIALNUMBER,
                strlcpy(serial_number, iSerialNumber, sizeof serial_number);
        }

        /* all we really need is bulk IN/OUT */
        usb_ep_autoconfig_reset (gadget);
        in_ep = usb_ep_autoconfig (gadget, &fs_source_desc);
        if (!in_ep) {
autoconf_fail:
                dev_err (&gadget->dev,
                        "can't autoconfigure on %s\n",
                        gadget->name);
                return -ENODEV;
        }
        in_ep->driver_data = in_ep;     /* claim */

        out_ep = usb_ep_autoconfig (gadget, &fs_sink_desc);
        if (!out_ep)
                goto autoconf_fail;
        out_ep->driver_data = out_ep;   /* claim */

#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
        /* CDC Ethernet control interface doesn't require a status endpoint.
         * Since some hosts expect one, try to allocate one anyway.
         */
        if (cdc || rndis) {
                status_ep = usb_ep_autoconfig (gadget, &fs_status_desc);
                if (status_ep) {
                        status_ep->driver_data = status_ep;     /* claim */
                } else if (rndis) {
                        dev_err (&gadget->dev,
                                "can't run RNDIS on %s\n",
                                gadget->name);
                        return -ENODEV;
#ifdef DEV_CONFIG_CDC
                /* pxa25x only does CDC subset; often used with RNDIS */
                } else if (cdc) {
                        control_intf.bNumEndpoints = 0;
                        /* FIXME remove endpoint from descriptor list */
#endif
                }
        }
#endif

        /* one config:  cdc, else minimal subset */
        if (!cdc) {
                eth_config.bNumInterfaces = 1;
                eth_config.iConfiguration = STRING_SUBSET;

                /* use functions to set these up, in case we're built to work
                 * with multiple controllers and must override CDC Ethernet.
                 */
                fs_subset_descriptors();
                hs_subset_descriptors();
        }

        device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
        usb_gadget_set_selfpowered (gadget);

        /* For now RNDIS is always a second config */
        if (rndis)
                device_desc.bNumConfigurations = 2;

        if (gadget_is_dualspeed(gadget)) {
                if (rndis)
                        dev_qualifier.bNumConfigurations = 2;
                else if (!cdc)
                        dev_qualifier.bDeviceClass = USB_CLASS_VENDOR_SPEC;

                /* assumes ep0 uses the same value for both speeds ... */
                dev_qualifier.bMaxPacketSize0 = device_desc.bMaxPacketSize0;

                /* and that all endpoints are dual-speed */
                hs_source_desc.bEndpointAddress =
                                fs_source_desc.bEndpointAddress;
                hs_sink_desc.bEndpointAddress =
                                fs_sink_desc.bEndpointAddress;
#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
                if (status_ep)
                        hs_status_desc.bEndpointAddress =
                                        fs_status_desc.bEndpointAddress;
#endif
        }

        if (gadget_is_otg(gadget)) {
                otg_descriptor.bmAttributes |= USB_OTG_HNP,
                eth_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
                eth_config.bMaxPower = 4;
#ifdef  CONFIG_USB_ETH_RNDIS
                rndis_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
                rndis_config.bMaxPower = 4;
#endif
        }

        net = alloc_etherdev (sizeof *dev);
        if (!net)
                return status;
        dev = netdev_priv(net);
        spin_lock_init (&dev->lock);
        spin_lock_init (&dev->req_lock);
        INIT_WORK (&dev->work, eth_work);
        INIT_LIST_HEAD (&dev->tx_reqs);
        INIT_LIST_HEAD (&dev->rx_reqs);

        /* network device setup */
        dev->net = net;
        strcpy (net->name, "usb%d");
        dev->cdc = cdc;
        dev->zlp = zlp;

        dev->in_ep = in_ep;
        dev->out_ep = out_ep;
        dev->status_ep = status_ep;

        /* Module params for these addresses should come from ID proms.
         * The host side address is used with CDC and RNDIS, and commonly
         * ends up in a persistent config database.  It's not clear if
         * host side code for the SAFE thing cares -- its original BLAN
         * thing didn't, Sharp never assigned those addresses on Zaurii.
         */
        if (get_ether_addr(dev_addr, net->dev_addr))
                dev_warn(&gadget->dev,
                        "using random %s ethernet address\n", "self");
        if (get_ether_addr(host_addr, dev->host_mac))
                dev_warn(&gadget->dev,
                        "using random %s ethernet address\n", "host");
        snprintf (ethaddr, sizeof ethaddr, "%02X%02X%02X%02X%02X%02X",
                dev->host_mac [0], dev->host_mac [1],
                dev->host_mac [2], dev->host_mac [3],
                dev->host_mac [4], dev->host_mac [5]);

        if (rndis) {
                status = rndis_init();
                if (status < 0) {
                        dev_err (&gadget->dev, "can't init RNDIS, %d\n",
                                status);
                        goto fail;
                }
        }

        net->change_mtu = eth_change_mtu;
        net->get_stats = eth_get_stats;
        net->hard_start_xmit = eth_start_xmit;
        net->open = eth_open;
        net->stop = eth_stop;
        // watchdog_timeo, tx_timeout ...
        // set_multicast_list
        SET_ETHTOOL_OPS(net, &ops);

        /* preallocate control message data and buffer */
        dev->req = eth_req_alloc (gadget->ep0, USB_BUFSIZ, GFP_KERNEL);
        if (!dev->req)
                goto fail;
        dev->req->complete = eth_setup_complete;

        /* ... and maybe likewise for status transfer */
#if defined(DEV_CONFIG_CDC) || defined(CONFIG_USB_ETH_RNDIS)
        if (dev->status_ep) {
                dev->stat_req = eth_req_alloc (dev->status_ep,
                                        STATUS_BYTECOUNT, GFP_KERNEL);
                if (!dev->stat_req) {
                        eth_req_free (gadget->ep0, dev->req);
                        goto fail;
                }
                dev->stat_req->context = NULL;
        }
#endif

        /* finish hookup to lower layer ... */
        dev->gadget = gadget;
        set_gadget_data (gadget, dev);
        gadget->ep0->driver_data = dev;

        /* two kinds of host-initiated state changes:
         *  - iff DATA transfer is active, carrier is "on"
         *  - tx queueing enabled if open *and* carrier is "on"
         */
        netif_stop_queue (dev->net);
        netif_carrier_off (dev->net);

        SET_NETDEV_DEV (dev->net, &gadget->dev);
        status = register_netdev (dev->net);
        if (status < 0)
                goto fail1;

        INFO (dev, "%s, version: " DRIVER_VERSION "\n", driver_desc);
        INFO (dev, "using %s, OUT %s IN %s%s%s\n", gadget->name,
                out_ep->name, in_ep->name,
                status_ep ? " STATUS " : "",
                status_ep ? status_ep->name : ""
                );
        INFO (dev, "MAC %02x:%02x:%02x:%02x:%02x:%02x\n",
                net->dev_addr [0], net->dev_addr [1],
                net->dev_addr [2], net->dev_addr [3],
                net->dev_addr [4], net->dev_addr [5]);

        if (cdc || rndis)
                INFO (dev, "HOST MAC %02x:%02x:%02x:%02x:%02x:%02x\n",
                        dev->host_mac [0], dev->host_mac [1],
                        dev->host_mac [2], dev->host_mac [3],
                        dev->host_mac [4], dev->host_mac [5]);

        if (rndis) {
                u32     vendorID = 0;

                /* FIXME RNDIS vendor id == "vendor NIC code" == ? */

                status = rndis_register(rndis_resp_avail, dev);
                if (status < 0) {
fail0:
                        unregister_netdev (dev->net);
                        goto fail;
                }
                dev->rndis_config = status;

                /* these set up a lot of the OIDs that RNDIS needs */
                rndis_set_host_mac (dev->rndis_config, dev->host_mac);
                if (rndis_set_param_dev (dev->rndis_config, dev->net,
                                         &dev->cdc_filter))
                        goto fail0;
                if (rndis_set_param_vendor(dev->rndis_config, vendorID,
                                        manufacturer))
                        goto fail0;
                if (rndis_set_param_medium(dev->rndis_config,
                                        NDIS_MEDIUM_802_3, 0))
                        goto fail0;
                INFO (dev, "RNDIS ready\n");
        }

        return status;

fail1:
        dev_dbg(&gadget->dev, "register_netdev failed, %d\n", status);
fail:
        eth_unbind (gadget);
        return status;
}

/*-------------------------------------------------------------------------*/

static void
eth_suspend (struct usb_gadget *gadget)
{
        struct eth_dev          *dev = get_gadget_data (gadget);

        DEBUG (dev, "suspend\n");
        dev->suspended = 1;
}

static void
eth_resume (struct usb_gadget *gadget)
{
        struct eth_dev          *dev = get_gadget_data (gadget);

        DEBUG (dev, "resume\n");
        dev->suspended = 0;
}

/*-------------------------------------------------------------------------*/

static struct usb_gadget_driver eth_driver = {
        .speed          = DEVSPEED,

        .function       = (char *) driver_desc,
        .bind           = eth_bind,
        .unbind         = eth_unbind,

        .setup          = eth_setup,
        .disconnect     = eth_disconnect,

        .suspend        = eth_suspend,
        .resume         = eth_resume,

        .driver = {
                .name           = (char *) shortname,
                .owner          = THIS_MODULE,
        },
};

MODULE_DESCRIPTION (DRIVER_DESC);
MODULE_AUTHOR ("David Brownell, Benedikt Spanger");
MODULE_LICENSE ("GPL");


static int __init init (void)
{
        return usb_gadget_register_driver (&eth_driver);
}
module_init (init);

static void __exit cleanup (void)
{
        usb_gadget_unregister_driver (&eth_driver);
}
module_exit (cleanup);