.\" $NetBSD: usbnet.9,v 1.9.2.2 2019/09/01 13:00:37 martin Exp $ .\" .\" Copyright (c) 2019 Matthew R. Green .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. The name of the author may not be used to endorse or promote products .\" derived from this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, .\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED .\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, .\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd August 22, 2019 .Dt USBNET 9 .Os .Sh NAME .Nm usbnet .Nd common USB Ethernet driver framework .Sh SYNOPSIS .In dev/usb/usbnet.h .Ss Functions offered by usbnet.h .Ft void .Fn usbnet_set_link "struct usbnet *un" "bool link" .Ft void .Fn usbnet_set_dying "struct usbnet *un" "bool dying" .Ft struct ifnet * .Fn usbnet_ifp "struct usbnet *un" .Ft struct ethercom * .Fn usbnet_ec "struct usbnet *un" .Ft struct mii_data * .Fn usbnet_mii "struct usbnet *un" .Ft krndsource_t * .Fn usbnet_rndsrc "struct usbnet *un" .Ft void * .Fn usbnet_softc "struct usbnet *un" .Ft bool .Fn usbnet_havelink "struct usbnet *un" .Ft bool .Fn usbnet_isdying "struct usbnet *un" .Ft void .Fn usbnet_lock "struct usbnet *un" .Ft void .Fn usbnet_unlock "struct usbnet *un" .Ft kmutex_t * .Fn usbnet_mutex "struct usbnet *un" .Ft void .Fn usbnet_isowned "struct usbnet *un" .Ft void .Fn usbnet_lock_rx "struct usbnet *un" .Ft void .Fn usbnet_unlock_rx "struct usbnet *un" .Ft kmutex_t * .Fn usbnet_mutex_rx "struct usbnet *un" .Ft void .Fn usbnet_isowned_rx "struct usbnet *un" .Ft void .Fn usbnet_lock_tx "struct usbnet *un" .Ft void .Fn usbnet_unlock_tx "struct usbnet *un" .Ft kmutex_t * .Fn usbnet_mutex_tx "struct usbnet *un" .Ft void .Fn usbnet_isowned_tx "struct usbnet *un" .Ft int .Fn usbnet_init_rx_tx "struct usbnet *un" "unsigned rxflags" "unsigned txflags" .Ft void .Fn usbnet_lock_mii "struct usbnet *un" .Ft void .Fn usbnet_lock_mii_un_locked "struct usbnet *un" .Ft void .Fn usbnet_unlock_mii "struct usbnet *un" .Ft void .Fn usbnet_unlock_mii_un_locked "struct usbnet *un" .Ft kmutex_t * .Fn usbnet_mutex_mii "struct usbnet *un" .Ft void .Fn usbnet_isowned_mii "struct usbnet *un" .Ft int .Fn usbnet_miibus_readreg "device_t dev" "int phy" "int reg" "uint16_t *val" .Ft int .Fn usbnet_miibus_writereg "device_t dev" "int phy" "int reg" "uint16_t val" .Ft void .Fn usbnet_miibus_statchg "struct ifnet *" .Ft void .Fn usbnet_enqueue "struct usbnet *un" "uint8_t *buf" "size_t buflen" "int csum_flags" "uint32_t csum_data" "int mbuf_flags" .Ft void .Fn usbnet_input "struct usbnet *un" "uint8_t *buf" "size_t buflen" .Ft void .Fn usbnet_attach "struct usbnet *un" "const char *detname" .Ft void .Fn usbnet_attach_ifp "struct usbnet *un" "unsigned if_flags" "unsigned if_extflags" "const struct usbnet_mii *unm" .Ft int .Fn usbnet_detach "device_t dev" "int flags" .Ft int .Fn usbnet_activate "device_t dev" "devact_t act" .Ft void .Fn usbnet_stop "struct usbnet *un" "struct ifnet *ifp" "int disable" .Sh DESCRIPTION The .Nm framework provides methods usable for USB Ethernet drivers. The framework has support for these features: .Bl -bullet -offset 8n .It Partial autoconf handling .It USB endpoint pipe handling .It Rx and Tx chain handling .It Generic handlers or support for several struct ifnet callbacks .It MII bus locking .It Interrupt handling .El .Pp .Nm provides many or all of the traditional .Dq softc members inside .Va struct usbnet , which can be used directly as the device softc structure if no additional storage is required. A structure exists for receive and transmit chain management, .Va struct usbnet_chain , that tracks the metadata for each transfer descriptor available, minimum of one each for Rx and Tx slot, and will be passed to the Rx and Tx callbacks. .Pp There is a .Va struct usbnet_ops structure that provides a number of optional and required callbacks that will be described below. .Pp For autoconfiguration the device attach routine is expected to ensure that this device's .Va struct usbnet is the first member of the device softc, if it can not be used directly as the device softc, as well as set up the necessary structure members, find end-points, find the Ethernet address if relevant, call .Fn usbnet_attach , set up interface, Ethernet, and MII capabilities, and finally call .Fn usbnet_attach_ifp . The device detach routine should free any resources allocated by attach and then call .Fn usbnet_detach , possibly directly using .Fn usbnet_detach as most consumers have no additional resources not owned and released by the .Nm framework itself. The device activate function should be set to .Fn usbnet_activate . .Pp To manage all Rx and Tx chains the .Dq uno_init callback of .Va struct usbnet_ops should perform any device specific initialization and then call .Fn usbnet_init_rx_tx which will allocate chains, set up and open pipes, and start the Rx transfers so that packets can arrived. These allocations and pipes can be closed and destroyed by calling .Fn usbnet_stop . Both of .Fn usbnet_init_rx_tx and .Fn usbnet_stop must be called with the .Nm lock held, see .Fn usbnet_lock and .Fn usbnet_unlock . See the .Sx RECEIVE AND SEND section for details on using the chains. .Pp The interface init, ioctl, start, and stop, routines are handled by the framework with callbacks for device-specific handling. For interface init (i.e., when bringing the interface up), the .Dq uno_init callback should perform any device specific initialization and then call .Fn usbnet_init_rx_tx to finalize Rx and Tx queue initialization. For interface ioctl, most of the handling is in the framework and the optional .Dq uno_ioctl callback should be used to program special settings like multicast filters or offload handling. If ioctl handling requires capturing device-specific ioctls then the .Dq uno_override_ioctl callback may be used instead to replace the framework's ioctl handler completely (i.e., the replacement should call any generic ioctl handlers such as .Fn ether_ioctl as required.) For interface start, the .Dq uno_tx_prepare callback must be used to convert an mbuf into a chain buffer ready for transmission. For interface stop, there is an optional .Dq uno_stop callback to turn off any chipset specific values if required. .Pp For devices requiring MII handling there are callbacks for reading and writing registers, and for status change events. The framework provides an MII-specific lock per interface which will be held when calling these functions, and these locks should be used by internal code that also requires serialized access to registers with the .Fn usbnet_lock_mii , .Fn usbnet_unlock_mii , .Fn usbnet_lock_mii_un_locked , and .Fn usbnet_unlock_mii_un_locked functions. These functions handle device detach events safely, and as such take and release a reference on this device and use the usbnet lock for this. Sometimes the usbnet lock is already held and instead the .Dq un_locked versions should be used. .Pp As receive must handle the case of multiple packets in one buffer, the support is split between the driver and the framework. A .Dq uno_rx_loop callback must be provided that loops over the incoming packet data found in a chain, performs necessary checking and passes the network frame up the stack via either .Fn usbnet_enqueue or .Fn usbnet_input . Typically Ethernet devices prefer .Fn usbnet_enqueue . .Pp General accessor functions for .Fa struct usbnet : .Bl -tag -width 4n .It Fn usbnet_set_link un link Set the link status for this .Fa un to .Fa link . .It Fn usbnet_set_dying un dying Set the dying status for this .Fa un to .Fa dying . .It Fn usbnet_ifp un Returns pointer to this .Fa un's .Va struct ifnet . .It Fn usbnet_ec un Returns pointer to this .Fa un's .Va struct ethercom . .It Fn usbnet_mii un Returns pointer to this .Fa un's .Va struct mii_data . .It Fn usbnet_rndsrc un Returns pointer to this .Fa un's .Va krndsource_t . .It Fn usbnet_softc un Returns pointer to this .Fa un's device softc. .It Fn bool usbnet_havelink un Returns true if link is active. .It Fn bool usbnet_isdying un Returns true if device is dying (has been pulled or deactivated, pending detach.) .El .Pp Lock handling functions for .Fa struct usbnet : .Pp .Bl -tag -width 4n -compact .It Fn usbnet_lock un .It Fn usbnet_unlock un .It Fn usbnet_isowned un .It Fn usbnet_lock_rx un .It Fn usbnet_unlock_rx un .It Fn usbnet_isowned_rx un .It Fn usbnet_lock_tx un .It Fn usbnet_unlock_tx un .It Fn usbnet_isowned_tx un .It Fn usbnet_lock_mii un .It Fn usbnet_lock_mii_un_locked un .It Fn usbnet_unlock_mii un .It Fn usbnet_unlock_mii_un_locked un .It Fn usbnet_isowned_mii un These groups of three or five functions provide methods to lock, unlock, and assert ownership of one of the four locks provided by .Nm . The four locks are the .Dq softc lock, the .Dq Tx lock, the .Dq Rx lock, and the .Dq MII lock. The MII lock is special in that it blocks device detach using an internal reference count and is frequently required when both the .Dq softc lock is held or unheld, and two versions are provided that either hold the .Dq softc lock while increasing or decreasing the reference count, or assume (and in debug builds, assert) the lock is held for the .Dq un_locked versions. .El .Pp MII access functions for .Fa struct usbnet : .Bl -tag -width 4n .It Fn usbnet_mii_readreg dev phy reg valp Read register .Fa reg on PHY number .Fa phy and return the value in .Fa valp . Called with the MII lock held. .It Fn usbnet_mii_writereg dev phy reg val Write register .Fa reg on PHY number .Fa phy with .Fa val . Called with the MII lock held. .It Fn usbnet_mii_statchg ifp Trigger a status change update for interface .Fa ifp . Unlike register access, called with the MII lock not held. .El .Pp Buffer enqueue handling for .Fa struct usbnet : .Bl -tag -width 4n .It Fn usbnet_enqueue un buf buflen csum_flags csum_data mbuf_flags Enqueue buffer .Fa buf for length .Fa buflen with higher layers, using the provided .Fa csum_flags , and .Fa csum_data , which are written directly to the mbuf packet header, and .Fa mbuf_flags , which is or-ed into the mbuf flags for the created mbuf. .It Fn usbnet_input un buf buflen Enqueue buffer .Fa buf for length .Fa buflen with higher layers .El .Pp Autoconfiguration handling for .Fa struct usbnet . See the .Sx AUTOCONFIGURATION section for more details about these functions. .Bl -tag -width 4n .It Fn usbnet_attach un detachname Initial stage attach of a usb network device. The .Fa detachname will be used while waiting for final references to drain when detaching. .It Fn usbnet_attach_ifp un if_flags if_extflags unm Final stage attach of usb network device. If the passed in .Fa unm is .Pf non- Dv NULL then an MII interface will be created using the values provided in the .Fa struct usbnet_mii structure, which has these members passed to .Fn mii_attach : .Bl -tag -width 4n .It un_mii_flags Flags. .It un_mii_capmask Capability mask. .It un_mii_phyloc PHY location. .It un_mii_offset PHY offset. .El .Pp A default .Fa unm can be set using the .Fn USBNET_MII_DECL_DEFAULT macro. The .Fa if_flags and .Fa if_extflags will be or-ed into the interface flags and extflags. .It Fn usbnet_detach dev flags Device detach. Usable as actual device method. .It Fn usbnet_activate dev act Device activate (deactivate) method. Usable as actual device method. .It Fn usbnet_stop un ifp disable Interface stop routine. .El .Sh AUTOCONFIGURATION The framework expects the usbnet structure to have these members filled in with valid values or functions: .Bl -tag -width 6n .It un_sc Real softc allocated by autoconf and provided to attach, should be set to the usbnet structure if no device-specific softc is needed. .It un_dev device_t saved in attach, used for messages mostly. .It un_iface The USB iface handle for data interactions, see .Fn usbd_device2interface_handle for more details. .It un_udev The struct usbd_device for this device, provided as the usb_attach_arg's .Va uaa_device member. .It un_ops Points to a .Va struct usbnet_ops structure which contains these members: .Bl -tag -width 4n .It Ft void Fn (*uno_stop) "struct ifnet *ifp" "int disable" Stop interface (optional.) .It Ft int Fn (*uno_ioctl) "struct ifnet *ifp" "u_long cmd" "void *data" Simple ioctl callback (optional.) .It Ft int Fn (*uno_override_ioctl) "struct ifnet *ifp" "u_long cmd" "void *data" Full ioctl callback (optional.) .It Ft int Fn (*uno_init) "struct ifnet *ifp" Initialize (bring up) interface. Required. Must call .Fn usbnet_rx_tx_init . .It Ft int Fn (*uno_read_reg) "struct usbnet *un" "int phy" "int reg" "uint16_t *val" Read MII register. Required with MII. .It Ft int Fn (*uno_write_reg) "struct usbnet *un" "int phy" "int reg" "uint16_t val" Write MII register. Required with MII. .It Ft usbd_status Fn (*uno_statchg) "struct ifnet *ifp" Handle MII status change. Required with MII. .It Ft unsigned Fn (*uno_tx_prepare) "struct usbnet *un" "struct mbuf *m" "struct usbnet_chain *c" Prepare an mbuf for transmit. Required. .It Ft void Fn (*uno_rx_loop) "struct usbnet *un" "struct usbnet_chain *c" "uint32_t total_len" Prepare one or more chain for enqueue. Required. .It Ft void Fn (*uno_intr) "struct usbnet *un" "usbd_status status" Process periodic interrupt (optional.) .It Ft void Fn (*uno_tick) "struct usbnet *un" Called every second with USB task thread context (optional.) .El .It un_intr Points to a .Va struct usbnet_intr structure which should have these members set: .Bl -tag -width 4n .It uni_intr_buf If .Pf non- Dv NULL , points to a buffer passed to .Fn usbd_open_pipe_intr in the device init callback, along with the size and interval. .It uni_intr_bufsz Size of interrupt pipe buffer. .It uni_intr_interval Frequency of the interrupt in milliseconds. .El .It un_ed Array of endpoint descriptors. There indexes are provided: .Dv USBNET_ENDPT_RX , .Dv USBNET_ENDPT_TX , and .Dv USBNET_ENDPT_INTR . The Rx and Tx endpoints are required. .It un_phyno MII phy number. Not used by .Nm . .It un_eaddr 6 bytes of Ethernet address that must be provided before calling .Fn usbnet_attach_ifp if the device has Ethernet. .It un_flags Device owned flags word. The .Nm framework will not touch this value. .It un_rx_xfer_flags Passed to .Fn usbd_setup_xfer for receiving packets. .It un_tx_xfer_flags Passed to .Fn usbd_setup_xfer for sending packets. .It un_rx_list_cnt Number of chain elements to allocate for Rx. .It un_tx_list_cnt Number of chain elements to allocate for Tx. .It un_rx_bufsz Rx buffer size. .It un_tx_bufsz Tx buffer size. .El .Pp The device detach and activate callbacks can typically be set to .Fn usbnet_detach and .Fn usbnet_activate unless device-specific handling is required, in which case, they can be called before or after such handling. .Pp The capabilities described in both .Va struct ifp and .Va struct ethercom must be set before calling .Fn usbnet_attach_ifp . .Sh RECEIVE AND SEND Receive and send routines are structured around a the .Va usbnet_cdata and .Va usbnet_chain structures, the .Dv un_ed , .Dv un_rx_xfer_flags , and .Dv un_tx_xfer_flags members, and the .Fn uno_stop , .Fn uno_init , .Fn uno_tx_prepare , and .Fn uno_rx_loop callbacks of .Va usbnet_ops . .Pp Typically, the device attach routine will fill in members of the .Va usbnet structure, as listed in .Sx AUTOCONFIGURATION . The .Fn un_ed member should have the .Dv USBNET_ENDPT_RX and .Dv USBNET_ENDPT_TX array entries filled in, and optionally the .Dv USBNET_ENDPT_INTR entry filled in if applicable. .Pp The optional .Fn uno_stop callback performs device-specific operations to shutdown the transmit or receive handling. .Fn uno_stop will be called with the usbnet lock held. .Pp The .Fn uno_init callback both performs device-specific enablement and then calls .Fn usbnet_rx_tx_init , which sets up the receive, transmit, and, optionally, the interrupt pipes, as well as starting the receive pipes. All USB transfer setup is handled internally to the framework, and the driver callbacks merely copy data in or out of a chain entry using what is typically a device-specific method. .Pp The .Fn uno_rx_loop callback converts the provided .Va usbnet_chain data and length into a series (one or more) of packets that are enqueued with the higher layers using either .Fn usbnet_enqueue (for most devices) or .Fn usbnet_input for devices that use .Fn if_input (this currently relies upon the .Va struct ifnet having the .Dq _if_input member set as well, which is true for current consumers.) The Rx lock will be held during this call, see .Fn usbnet_lock_rx and .Fn usbnet_unlock_rx . .Pp The .Fn uno_tx_prepare callback must convert the provided .Va struct mbuf into the provided .Va struct usbnet_chain performing any device-specific padding, checksum, header or other. Note that this callback must check that it is not attempting to copy more than the chain buffer size, as set in the .Va usbnet .Dq un_tx_bufsz member. This callback is only called once per packet. The Tx lock will be held during this call, see .Fn usbnet_lock_tx and .Fn usbnet_unlock_tx . .Pp The .Fa struct usbnet_chain structure which contains a .Dq unc_buf member which has the chain buffer allocated where data should be copied to or from for receive or transmit operations. It also contains pointers back to the owning .Fa struct usbnet , and the .Va struct usbd_xfer associated with this transfer. .Sh MII For devices that have MII support these callbacks in .Fa struct usbnet_ops must be provided: .Bl -tag -width 4n .It uno_read_reg Read an MII register for a particular PHY. Returns standard .Xr errno 2 . .It uno_write_reg Write an MII register for a particular PHY. Returns standard .Xr errno 2 . .It uno_statchg Handle a status change event for this interface. .El The read and write callbacks are called with the MII lock held. See .Fn usbnet_lock_mii and .Fn usbnet_unlock_mii . .Sh INTERRUPT PIPE The interrupt specific callback, .Dq uno_intr , is an optional callback that can be called periodically, registered by .Nm using the .Fn usbd_open_pipe_intr function (instead of the .Fn usbd_open_pipe function.) The .Nm framework provides most of the interrupt handling and the callback simply inspects the returned buffer as necessary. To enable the this callback point the .Va struct usbnet member .Dq un_intr to a .Va struct usbnet_intr structure with these members set: .Bl -tag -width 4n .It uni_buf Data buffer for interrupt status relies. .It uni_bufsz Size of the above buffer. .It uni_interval Interval in millieconds. .El .Pp These values will be passed to .Fn usbd_open_pipe_intr . .Sh CONVERTING OLD-STYLE DRIVERS The porting of an older driver to the .Nm framework is largely an effort in deleting code. The process involves making these changes: .Bl -tag -width 4n .It Headers Many headers are included in .Pa usbnet.h and can be removed from the driver, as well as headers no longer used, such as .Pa callout.h and .Pa rndsource.h , etc. .It Device softc The majority of the driver's existing .Dq softc structure can likely be replaced with usage of .Va struct usbnet and its related functionality. This includes at least the device_t pointer, Ethernet address, the ethercom and mii_data structures, end point descriptors, usbd device, interface, and task and callout structures (both these probably go away entirely) and all the associated watchdog handling, timevals, list size, buffer size and xfer flags for both Rx, and Tx, and interrupt notices, interface flags, device link, PHY number, chain data, locks including Rx, Tx, MII, and the base softc lock. There is a driver-only .Dq un_flags in the .Va usbnet structure available for drivers to use. .Pp Many drivers can use the .Va usbnet structure as the device private storage passed to .Dv CFATTACH_DECL_NEW . Many internal functions to the driver may look better if switched to operate on the device's .Va usbnet as, for example, the .Va usbd_device value is now available (and must be set by the driver) in the .Va usbnet , which may be needed for any call to .Fn usbd_do_request . The standard endpoint values must be stored in the .Nm .Dq un_ed[] array. .Pp As .Nm manages xfer chains all code related to the opening, closing, aborting and transferring of data on pipes is performed by the framework based upon the buffer size and more provided in .Va subnet , so all code related to them should be deleted. .It Interface setup The vast majority of interface specific code should be deleted. For device-specific interface values, the .Va ifnet flags and exflags can be set, as well as the .Va ethercom .Dq ec_capabilities member, before calling .Fn usbnet_attach_ifp . All calls to .Fn ifmedia_init , .Fn mii_attach , .Fn ifmedia_add , .Fn ifmedia_set , .Fn if_attach , .Fn ether_ifattach , .Fn rnd_attach_source , and .Fn usbd_add_drv_event should be eliminated. The device .Dq ioctl routine can use the default handling with a callback for additional device specific programming (multicast filters, etc.), which can be empty, or, the override ioctl can be used for heavier requirements. The device .Dq stop routine is replaced with a simple call that turns off the device-specific transmitter and receiver if necessary, as the framework handles pipes and transfers and buffers. .It Device locking The .Nm framework provides four locks for the system: normal device/softc lock, receive and transmit locks, and the MII lock. The normal locking order for these locks is ifnet lock -> usbnet lock -> usbnet rxlock -> usbne txlock, or, ifnet lock -> usbnet lock -> MII lock. .It MII handling For devices with MII support the three normal callbacks (read, write, and status change) must be converted to .Va usbnet . These functions are called with the MII lock is held (see .Dq Fn usbnet_isowned_mii ) , and do not require any checking for running, or up, or dying devices unless they drop and retake the MII lock. Local .Dq link variables need to be replaced with accesses to .Fn usbnet_set_link and .Fn usbnet_havelink . Other ifmedia callbacks that were passed to .Fn ifmedia_init should be deleted and any work moved into .Dq uno_statchg . .It Receive and Transmit The .Nm framework handles the majority of handling of both network directions. The interface init routine should keep all of the device specific setup but replace all pipe management with a call to .Fn usbnet_init_rx_tx . The typical receive handling will normally be replaced with a receive loop functions that can accept one or more packets, .Dq uno_rx_loop , which can use either .Fn usbnet_enqueue or .Fn usbnet_input to pass the packets upto higher layers. The typical interface .Dq if_start function and any additional functions used will normal be replaced with a relatively simple .Dq uno_tx_prepare function that simply converts an .Va mbuf into a .Va usbnet_chain useful for this device that will be passed onto .Fn usbd_transfer . The framework's handling of the Tx interrupt is all internal. .It Interrupt pipe handling For devices requiring special handling of the interrupt pipe (i.e., they use the .Fn usbd_open_pipe_intr method), most of the interrupt handler should be deleted, leaving only code that inspects the result of the interrupt transfer. .It Common errors It's common to forget to set link active on devices with MII. Be sure to call .Fn usbent_set_link during any status change event. .Pp Many locking issues are hidden without .Dv LOCKDEBUG , including hard-hangs. It's highly recommended to develop with .Dv LOCKDEBUG . .Pp The .Va usbnet .Dq un_ed array is unsigned and should use .Dq 0 as the no-endpoint value. .El .Sh SEE ALSO .Xr usb 4 , .Xr driver 9 , .Xr usbd_status 9 , .Xr usbdi 9 .Sh HISTORY This .Nm interface first appeared in .Nx 9.0 . Portions of the original design are based upon ideas from .An Nick Hudson Aq Mt skrll@NetBSD.org . .Sh AUTHORS .An Matthew R. Green Aq Mt mrg@eterna.com.au