Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

4 files changed, 439 insertions, 0 deletions

diff --git a/Documentation/isdn/credits.rst b/Documentation/isdn/credits.rst
new file mode 100644
index 000000000..319323f20
--- /dev/null
+++ b/Documentation/isdn/credits.rst
@@ -0,0 +1,73 @@
+=======
+Credits
+=======
+
+
+I want to thank all who contributed to this project and especially to:
+(in alphabetical order)
+
+Thomas Bogendörfer (tsbogend@bigbug.franken.de)
+  Tester, lots of bugfixes and hints.
+
+Alan Cox (alan@lxorguk.ukuu.org.uk)
+  For help getting into standard-kernel.
+
+Henner Eisen (eis@baty.hanse.de)
+  For X.25 implementation.
+
+Volker Götz (volker@oops.franken.de)
+  For contribution of man-pages, the imontty-tool and a perfect
+  maintaining of the mailing-list at hub-wue.
+
+Matthias Hessler (hessler@isdn4linux.de)
+  For creating and maintaining the FAQ.
+
+Bernhard Hailer (Bernhard.Hailer@lrz.uni-muenchen.de)
+  For creating the FAQ, and the leafsite HOWTO.
+
+Michael 'Ghandi' Herold (michael@abadonna.franken.de)
+  For contribution of the vbox answering machine.
+
+Michael Hipp (Michael.Hipp@student.uni-tuebingen.de)
+  For his Sync-PPP-code.
+
+Karsten Keil (keil@isdn4linux.de)
+  For adding 1TR6-support to the Teles-driver.
+  For the HiSax-driver.
+
+Michael Knigge (knick@cove.han.de)
+  For contributing the imon-tool
+
+Andreas Kool (akool@Kool.f.EUnet.de)
+  For contribution of the isdnlog/isdnrep-tool
+
+Pedro Roque Marques (roque@di.fc.ul.pt)
+  For lot of new ideas and the pcbit driver.
+
+Eberhard Mönkeberg (emoenke@gwdg.de)
+  For testing and help to get into kernel.
+
+Thomas Neumann (tn@ruhr.de)
+  For help with Cisco-SLARP and keepalive
+
+Jan den Ouden (denouden@groovin.xs4all.nl)
+  For contribution of the original teles-driver
+
+Carsten Paeth (calle@calle.in-berlin.de)
+  For the AVM-B1-CAPI2.0 driver
+
+Thomas Pfeiffer (pfeiffer@pds.de)
+  For V.110, extended T.70 and Hylafax extensions in isdn_tty.c
+
+Max Riegel (riegel@max.franken.de)
+  For making the ICN hardware-documentation and test-equipment available.
+
+Armin Schindler (mac@melware.de)
+  For the eicon active card driver.
+
+Gerhard 'Fido' Schneider (fido@wuff.mayn.de)
+  For heavy-duty-beta-testing with his BBS ;)
+
+Thomas Uhl (uhl@think.de)
+  For distributing the cards.
+  For pushing me to work ;-)
diff --git a/Documentation/isdn/index.rst b/Documentation/isdn/index.rst
new file mode 100644
index 000000000..9622939fa
--- /dev/null
+++ b/Documentation/isdn/index.rst
@@ -0,0 +1,21 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+====
+ISDN
+====
+
+.. toctree::
+   :maxdepth: 2
+
+   interface_capi
+
+   m_isdn
+
+   credits
+
+.. only::  subproject and html
+
+   Indices
+   =======
+
+   * :ref:`genindex`
diff --git a/Documentation/isdn/interface_capi.rst b/Documentation/isdn/interface_capi.rst
new file mode 100644
index 000000000..4d63b34b3
--- /dev/null
+++ b/Documentation/isdn/interface_capi.rst
@@ -0,0 +1,336 @@
+=========================================
+Kernel CAPI Interface to Hardware Drivers
+=========================================
+
+1. Overview
+===========
+
+From the CAPI 2.0 specification:
+COMMON-ISDN-API (CAPI) is an application programming interface standard used
+to access ISDN equipment connected to basic rate interfaces (BRI) and primary
+rate interfaces (PRI).
+
+Kernel CAPI operates as a dispatching layer between CAPI applications and CAPI
+hardware drivers. Hardware drivers register ISDN devices (controllers, in CAPI
+lingo) with Kernel CAPI to indicate their readiness to provide their service
+to CAPI applications. CAPI applications also register with Kernel CAPI,
+requesting association with a CAPI device. Kernel CAPI then dispatches the
+application registration to an available device, forwarding it to the
+corresponding hardware driver. Kernel CAPI then forwards CAPI messages in both
+directions between the application and the hardware driver.
+
+Format and semantics of CAPI messages are specified in the CAPI 2.0 standard.
+This standard is freely available from https://www.capi.org.
+
+
+2. Driver and Device Registration
+=================================
+
+CAPI drivers must register each of the ISDN devices they control with Kernel
+CAPI by calling the Kernel CAPI function attach_capi_ctr() with a pointer to a
+struct capi_ctr before they can be used. This structure must be filled with
+the names of the driver and controller, and a number of callback function
+pointers which are subsequently used by Kernel CAPI for communicating with the
+driver. The registration can be revoked by calling the function
+detach_capi_ctr() with a pointer to the same struct capi_ctr.
+
+Before the device can be actually used, the driver must fill in the device
+information fields 'manu', 'version', 'profile' and 'serial' in the capi_ctr
+structure of the device, and signal its readiness by calling capi_ctr_ready().
+From then on, Kernel CAPI may call the registered callback functions for the
+device.
+
+If the device becomes unusable for any reason (shutdown, disconnect ...), the
+driver has to call capi_ctr_down(). This will prevent further calls to the
+callback functions by Kernel CAPI.
+
+
+3. Application Registration and Communication
+=============================================
+
+Kernel CAPI forwards registration requests from applications (calls to CAPI
+operation CAPI_REGISTER) to an appropriate hardware driver by calling its
+register_appl() callback function. A unique Application ID (ApplID, u16) is
+allocated by Kernel CAPI and passed to register_appl() along with the
+parameter structure provided by the application. This is analogous to the
+open() operation on regular files or character devices.
+
+After a successful return from register_appl(), CAPI messages from the
+application may be passed to the driver for the device via calls to the
+send_message() callback function. Conversely, the driver may call Kernel
+CAPI's capi_ctr_handle_message() function to pass a received CAPI message to
+Kernel CAPI for forwarding to an application, specifying its ApplID.
+
+Deregistration requests (CAPI operation CAPI_RELEASE) from applications are
+forwarded as calls to the release_appl() callback function, passing the same
+ApplID as with register_appl(). After return from release_appl(), no CAPI
+messages for that application may be passed to or from the device anymore.
+
+
+4. Data Structures
+==================
+
+4.1 struct capi_driver
+----------------------
+
+This structure describes a Kernel CAPI driver itself. It is used in the
+register_capi_driver() and unregister_capi_driver() functions, and contains
+the following non-private fields, all to be set by the driver before calling
+register_capi_driver():
+
+``char name[32]``
+	the name of the driver, as a zero-terminated ASCII string
+``char revision[32]``
+	the revision number of the driver, as a zero-terminated ASCII string
+
+4.2 struct capi_ctr
+-------------------
+
+This structure describes an ISDN device (controller) handled by a Kernel CAPI
+driver. After registration via the attach_capi_ctr() function it is passed to
+all controller specific lower layer interface and callback functions to
+identify the controller to operate on.
+
+It contains the following non-private fields:
+
+to be set by the driver before calling attach_capi_ctr():
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+``struct module *owner``
+	pointer to the driver module owning the device
+
+``void *driverdata``
+	an opaque pointer to driver specific data, not touched by Kernel CAPI
+
+``char name[32]``
+	the name of the controller, as a zero-terminated ASCII string
+
+``char *driver_name``
+	the name of the driver, as a zero-terminated ASCII string
+
+``int (*load_firmware)(struct capi_ctr *ctrlr, capiloaddata *ldata)``
+	(optional) pointer to a callback function for sending firmware and
+	configuration data to the device
+
+	The function may return before the operation has completed.
+
+	Completion must be signalled by a call to capi_ctr_ready().
+
+	Return value: 0 on success, error code on error
+	Called in process context.
+
+``void (*reset_ctr)(struct capi_ctr *ctrlr)``
+	(optional) pointer to a callback function for stopping the device,
+	releasing all registered applications
+
+	The function may return before the operation has completed.
+
+	Completion must be signalled by a call to capi_ctr_down().
+
+	Called in process context.
+
+``void (*register_appl)(struct capi_ctr *ctrlr, u16 applid, capi_register_params *rparam)``
+	pointers to callback function for registration of
+	applications with the device
+
+	Calls to these functions are serialized by Kernel CAPI so that only
+	one call to any of them is active at any time.
+
+``void (*release_appl)(struct capi_ctr *ctrlr, u16 applid)``
+	pointers to callback functions deregistration of
+	applications with the device
+
+	Calls to these functions are serialized by Kernel CAPI so that only
+	one call to any of them is active at any time.
+
+``u16  (*send_message)(struct capi_ctr *ctrlr, struct sk_buff *skb)``
+	pointer to a callback function for sending a CAPI message to the
+	device
+
+	Return value: CAPI error code
+
+	If the method returns 0 (CAPI_NOERROR) the driver has taken ownership
+	of the skb and the caller may no longer access it. If it returns a
+	non-zero (error) value then ownership of the skb returns to the caller
+	who may reuse or free it.
+
+	The return value should only be used to signal problems with respect
+	to accepting or queueing the message. Errors occurring during the
+	actual processing of the message should be signaled with an
+	appropriate reply message.
+
+	May be called in process or interrupt context.
+
+	Calls to this function are not serialized by Kernel CAPI, ie. it must
+	be prepared to be re-entered.
+
+``char *(*procinfo)(struct capi_ctr *ctrlr)``
+	pointer to a callback function returning the entry for the device in
+	the CAPI controller info table, /proc/capi/controller
+
+Note:
+  Callback functions except send_message() are never called in interrupt
+  context.
+
+to be filled in before calling capi_ctr_ready():
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+``u8 manu[CAPI_MANUFACTURER_LEN]``
+	value to return for CAPI_GET_MANUFACTURER
+
+``capi_version version``
+	value to return for CAPI_GET_VERSION
+
+``capi_profile profile``
+	value to return for CAPI_GET_PROFILE
+
+``u8 serial[CAPI_SERIAL_LEN]``
+	value to return for CAPI_GET_SERIAL
+
+
+4.3 SKBs
+--------
+
+CAPI messages are passed between Kernel CAPI and the driver via send_message()
+and capi_ctr_handle_message(), stored in the data portion of a socket buffer
+(skb).  Each skb contains a single CAPI message coded according to the CAPI 2.0
+standard.
+
+For the data transfer messages, DATA_B3_REQ and DATA_B3_IND, the actual
+payload data immediately follows the CAPI message itself within the same skb.
+The Data and Data64 parameters are not used for processing. The Data64
+parameter may be omitted by setting the length field of the CAPI message to 22
+instead of 30.
+
+
+4.4 The _cmsg Structure
+-----------------------
+
+(declared in <linux/isdn/capiutil.h>)
+
+The _cmsg structure stores the contents of a CAPI 2.0 message in an easily
+accessible form. It contains members for all possible CAPI 2.0 parameters,
+including subparameters of the Additional Info and B Protocol structured
+parameters, with the following exceptions:
+
+* second Calling party number (CONNECT_IND)
+
+* Data64 (DATA_B3_REQ and DATA_B3_IND)
+
+* Sending complete (subparameter of Additional Info, CONNECT_REQ and INFO_REQ)
+
+* Global Configuration (subparameter of B Protocol, CONNECT_REQ, CONNECT_RESP
+  and SELECT_B_PROTOCOL_REQ)
+
+Only those parameters appearing in the message type currently being processed
+are actually used. Unused members should be set to zero.
+
+Members are named after the CAPI 2.0 standard names of the parameters they
+represent. See <linux/isdn/capiutil.h> for the exact spelling. Member data
+types are:
+
+=========== =================================================================
+u8          for CAPI parameters of type 'byte'
+
+u16         for CAPI parameters of type 'word'
+
+u32         for CAPI parameters of type 'dword'
+
+_cstruct    for CAPI parameters of type 'struct'
+	    The member is a pointer to a buffer containing the parameter in
+	    CAPI encoding (length + content). It may also be NULL, which will
+	    be taken to represent an empty (zero length) parameter.
+	    Subparameters are stored in encoded form within the content part.
+
+_cmstruct   alternative representation for CAPI parameters of type 'struct'
+	    (used only for the 'Additional Info' and 'B Protocol' parameters)
+	    The representation is a single byte containing one of the values:
+	    CAPI_DEFAULT: The parameter is empty/absent.
+	    CAPI_COMPOSE: The parameter is present.
+	    Subparameter values are stored individually in the corresponding
+	    _cmsg structure members.
+=========== =================================================================
+
+
+5. Lower Layer Interface Functions
+==================================
+
+::
+
+  int attach_capi_ctr(struct capi_ctr *ctrlr)
+  int detach_capi_ctr(struct capi_ctr *ctrlr)
+
+register/unregister a device (controller) with Kernel CAPI
+
+::
+
+  void capi_ctr_ready(struct capi_ctr *ctrlr)
+  void capi_ctr_down(struct capi_ctr *ctrlr)
+
+signal controller ready/not ready
+
+::
+
+  void capi_ctr_handle_message(struct capi_ctr * ctrlr, u16 applid,
+			       struct sk_buff *skb)
+
+pass a received CAPI message to Kernel CAPI
+for forwarding to the specified application
+
+
+6. Helper Functions and Macros
+==============================
+
+Macros to extract/set element values from/in a CAPI message header
+(from <linux/isdn/capiutil.h>):
+
+======================  =============================   ====================
+Get Macro		Set Macro			Element (Type)
+======================  =============================   ====================
+CAPIMSG_LEN(m)		CAPIMSG_SETLEN(m, len)		Total Length (u16)
+CAPIMSG_APPID(m)	CAPIMSG_SETAPPID(m, applid)	ApplID (u16)
+CAPIMSG_COMMAND(m)	CAPIMSG_SETCOMMAND(m,cmd)	Command (u8)
+CAPIMSG_SUBCOMMAND(m)	CAPIMSG_SETSUBCOMMAND(m, cmd)	Subcommand (u8)
+CAPIMSG_CMD(m)		-				Command*256
+							+ Subcommand (u16)
+CAPIMSG_MSGID(m)	CAPIMSG_SETMSGID(m, msgid)	Message Number (u16)
+
+CAPIMSG_CONTROL(m)	CAPIMSG_SETCONTROL(m, contr)	Controller/PLCI/NCCI
+							(u32)
+CAPIMSG_DATALEN(m)	CAPIMSG_SETDATALEN(m, len)	Data Length (u16)
+======================  =============================   ====================
+
+
+Library functions for working with _cmsg structures
+(from <linux/isdn/capiutil.h>):
+
+``char *capi_cmd2str(u8 Command, u8 Subcommand)``
+	Returns the CAPI 2.0 message name corresponding to the given command
+	and subcommand values, as a static ASCII string. The return value may
+	be NULL if the command/subcommand is not one of those defined in the
+	CAPI 2.0 standard.
+
+
+7. Debugging
+============
+
+The module kernelcapi has a module parameter showcapimsgs controlling some
+debugging output produced by the module. It can only be set when the module is
+loaded, via a parameter "showcapimsgs=<n>" to the modprobe command, either on
+the command line or in the configuration file.
+
+If the lowest bit of showcapimsgs is set, kernelcapi logs controller and
+application up and down events.
+
+In addition, every registered CAPI controller has an associated traceflag
+parameter controlling how CAPI messages sent from and to the controller are
+logged. The traceflag parameter is initialized with the value of the
+showcapimsgs parameter when the controller is registered, but can later be
+changed via the MANUFACTURER_REQ command KCAPI_CMD_TRACE.
+
+If the value of traceflag is non-zero, CAPI messages are logged.
+DATA_B3 messages are only logged if the value of traceflag is > 2.
+
+If the lowest bit of traceflag is set, only the command/subcommand and message
+length are logged. Otherwise, kernelcapi logs a readable representation of
+the entire message.
diff --git a/Documentation/isdn/m_isdn.rst b/Documentation/isdn/m_isdn.rst
new file mode 100644
index 000000000..5847a1642
--- /dev/null
+++ b/Documentation/isdn/m_isdn.rst
@@ -0,0 +1,9 @@
+============
+mISDN Driver
+============
+
+mISDN is a new modular ISDN driver, in the long term it should replace
+the old I4L driver architecture for passive ISDN cards.
+It was designed to allow a broad range of applications and interfaces
+but only have the basic function in kernel, the interface to the user
+space is based on sockets with a own address family AF_ISDN.