Commit f7af616c authored by M Chetan Kumar's avatar M Chetan Kumar Committed by David S. Miller
Browse files

net: iosm: infrastructure 



1) Kconfig & Makefile changes for IOSM Driver compilation.
2) Add IOSM Driver documentation.
3) Modified MAINTAINER file for IOSM Driver addition.

Signed-off-by: default avatarM Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2a54f2c7

Documentation/networking/device_drivers/index.rst

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@@ -18,6 +18,7 @@ Contents: 
   qlogic/index

   wan/index

   wifi/index

   wwan/index



.. only::  subproject and html

Documentation/networking/device_drivers/wwan/index.rst

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.. SPDX-License-Identifier: GPL-2.0-only



WWAN Device Drivers

===================



Contents:



.. toctree::

   :maxdepth: 2



   iosm



.. only::  subproject and html



   Indices

   =======



   * :ref:`genindex`

Documentation/networking/device_drivers/wwan/iosm.rst

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.. SPDX-License-Identifier: GPL-2.0-only



.. Copyright (C) 2020-21 Intel Corporation



.. _iosm_driver_doc:



===========================================

IOSM Driver for Intel M.2 PCIe based Modems

===========================================

The IOSM (IPC over Shared Memory) driver is a WWAN PCIe host driver developed

for linux or chrome platform for data exchange over PCIe interface between

Host platform & Intel M.2 Modem. The driver exposes interface conforming to the

MBIM protocol [1]. Any front end application ( eg: Modem Manager) could easily

manage the MBIM interface to enable data communication towards WWAN.



Basic usage

===========

MBIM functions are inactive when unmanaged. The IOSM driver only provides a

userspace interface MBIM "WWAN PORT" representing MBIM control channel and does

not play any role in managing the functionality. It is the job of a userspace

application to detect port enumeration and enable MBIM functionality.



Examples of few such userspace application are:

- mbimcli (included with the libmbim [2] library), and

- Modem Manager [3]



Management Applications to carry out below required actions for establishing

MBIM IP session:

- open the MBIM control channel

- configure network connection settings

- connect to network

- configure IP network interface



Management application development

==================================

The driver and userspace interfaces are described below. The MBIM protocol is

described in [1] Mobile Broadband Interface Model v1.0 Errata-1.



MBIM control channel userspace ABI

----------------------------------



/dev/wwan0mbim0 character device

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The driver exposes an MBIM interface to the MBIM function by implementing

MBIM WWAN Port. The userspace end of the control channel pipe is a

/dev/wwan0mbim0 character device. Application shall use this interface for

MBIM protocol communication.



Fragmentation

~~~~~~~~~~~~~

The userspace application is responsible for all control message fragmentation

and defragmentation as per MBIM specification.



/dev/wwan0mbim0 write()

~~~~~~~~~~~~~~~~~~~~~

The MBIM control messages from the management application must not exceed the

negotiated control message size.



/dev/wwan0mbim0 read()

~~~~~~~~~~~~~~~~~~~~

The management application must accept control messages of up the negotiated

control message size.



MBIM data channel userspace ABI

-------------------------------



wwan0-X network device

~~~~~~~~~~~~~~~~~~~~

The IOSM driver exposes IP link interface "wwan0-X" of type "wwan" for IP

traffic. Iproute network utility is used for creating "wwan0-X" network

interface and for associating it with MBIM IP session. The Driver supports

upto 8 IP sessions for simultaneous IP communication.



The userspace management application is responsible for creating new IP link

prior to establishing MBIM IP session where the SessionId is greater than 0.



For example, creating new IP link for a MBIM IP session with SessionId 1:



  ip link add dev wwan0-1 parentdev-name wwan0 type wwan linkid 1



The driver will automatically map the "wwan0-1" network device to MBIM IP

session 1.



References

==========

[1] "MBIM (Mobile Broadband Interface Model) Errata-1"

      - https://www.usb.org/document-library/



[2] libmbim - "a glib-based library for talking to WWAN modems and

      devices which speak the Mobile Interface Broadband Model (MBIM)

      protocol"

      - http://www.freedesktop.org/wiki/Software/libmbim/



[3] Modem Manager - "a DBus-activated daemon which controls mobile

      broadband (2G/3G/4G) devices and connections"

      - http://www.freedesktop.org/wiki/Software/ModemManager/

MAINTAINERS

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@@ -9453,6 +9453,13 @@ L: Dell.Client.Kernel@dell.com 
S:	Maintained

F:	drivers/platform/x86/intel-wmi-thunderbolt.c









INTEL WWAN IOSM DRIVER









M:	M Chetan Kumar <m.chetan.kumar@intel.com>









M:	Intel Corporation <linuxwwan@intel.com>









L:	netdev@vger.kernel.org









S:	Maintained









F:	drivers/net/wwan/iosm/

















INTEL(R) TRACE HUB









M:	Alexander Shishkin <alexander.shishkin@linux.intel.com>









S:	Supported
































drivers/net/wwan/Kconfig



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@@ -44,4 +44,16 @@ config MHI_WWAN_CTRL







	  To compile this driver as a module, choose M here: the module will be









	  called mhi_wwan_ctrl.



















config IOSM









	tristate "IOSM Driver for Intel M.2 WWAN Device"









	select WWAN_CORE









	depends on INTEL_IOMMU









	help









	  This driver enables Intel M.2 WWAN Device communication.



















	  If you have one of those Intel M.2 WWAN Modules and wish to use it in









	  Linux say Y/M here.



















	  If unsure, say N.



















endif # WWAN