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| -rw-r--r-- | Documentation/networking/can.txt | 44 |
1 files changed, 40 insertions, 4 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index 297ba7b1ccaf..2035bc4932f2 100644 --- a/Documentation/networking/can.txt +++ b/Documentation/networking/can.txt @@ -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CAN) network interface 'vcan42': + ip link del vcan42 + + The tool 'vcan' from the SocketCAN SVN repository on BerliOS is obsolete.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 |