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Commit e5d23048 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by David S. Miller
Browse files

can: Add documentation for virtual CAN driver usage 



This patch adds a usage documentation for the virtual CAN driver (vcan).

Signed-off-by: default avatarOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 28e3487b

Documentation/networking/can.txt

+40 −4
Original line number Diff line number Diff line
@@ -35,8 +35,9 @@ This file contains 
    6.1 general settings

    6.2 local loopback of sent frames

    6.3 CAN controller hardware filters

    6.4 currently supported CAN hardware

    6.5 todo

    6.4 The virtual CAN driver (vcan)

    6.5 currently supported CAN hardware

    6.6 todo



  7 Credits
@@ -584,7 +585,42 @@ solution for a couple of reasons: 
  @133MHz with four SJA1000 CAN controllers from 2002 under heavy bus

  load without any problems ...



  6.4 currently supported CAN hardware (September 2007)

  6.4 The virtual CAN driver (vcan)



  Similar to the network loopback devices, vcan offers a virtual local

  CAN interface. A full qualified address on CAN consists of



  - a unique CAN Identifier (CAN ID)

  - the CAN bus this CAN ID is transmitted on (e.g. can0)



  so in common use cases more than one virtual CAN interface is needed.



  The virtual CAN interfaces allow the transmission and reception of CAN

  frames without real CAN controller hardware. Virtual CAN network

  devices are usually named 'vcanX', like vcan0 vcan1 vcan2 ...

  When compiled as a module the virtual CAN driver module is called vcan.ko



  Since Linux Kernel version 2.6.24 the vcan driver supports the Kernel

  netlink interface to create vcan network devices. The creation and

  removal of vcan network devices can be managed with the ip(8) tool:



  - Create a virtual CAN network interface:

       ip link add type vcan



  - Create a virtual CAN network interface with a specific name 'vcan42':

       ip link add dev vcan42 type vcan



  - Remove a (virtual CAN) network interface 'vcan42':

       ip link del vcan42



  The tool 'vcan' from the SocketCAN SVN repository on BerliOS is obsolete.



  Virtual CAN network device creation in older Kernels:

  In Linux Kernel versions < 2.6.24 the vcan driver creates 4 vcan

  netdevices at module load time by default. This value can be changed

  with the module parameter 'numdev'. E.g. 'modprobe vcan numdev=8'



  6.5 currently supported CAN hardware



  On the project website http://developer.berlios.de/projects/socketcan

  there are different drivers available:
@@ -603,7 +639,7 @@ solution for a couple of reasons: 


  Please check the Mailing Lists on the berlios OSS project website.



  6.5 todo (September 2007)

  6.6 todo



  The configuration interface for CAN network drivers is still an open

  issue that has not been finalized in the socketcan project. Also the