diff options
author | Oliver Hartkopp <oliver@hartkopp.net> | 2008-09-23 17:53:14 -0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-09-23 17:53:14 -0400 |
commit | e5d2304802a63304a54cff010209c4a717a2509f (patch) | |
tree | 978aaba0b03f6bf9564d7c55c6e9332d046060cb /Documentation | |
parent | 28e3487b7dd8a9791baac924bc887140ec747bed (diff) |
can: Add documentation for virtual CAN driver usage
This patch adds a usage documentation for the virtual CAN driver (vcan).
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
-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 | |||
35 | 6.1 general settings | 35 | 6.1 general settings |
36 | 6.2 local loopback of sent frames | 36 | 6.2 local loopback of sent frames |
37 | 6.3 CAN controller hardware filters | 37 | 6.3 CAN controller hardware filters |
38 | 6.4 currently supported CAN hardware | 38 | 6.4 The virtual CAN driver (vcan) |
39 | 6.5 todo | 39 | 6.5 currently supported CAN hardware |
40 | 6.6 todo | ||
40 | 41 | ||
41 | 7 Credits | 42 | 7 Credits |
42 | 43 | ||
@@ -584,7 +585,42 @@ solution for a couple of reasons: | |||
584 | @133MHz with four SJA1000 CAN controllers from 2002 under heavy bus | 585 | @133MHz with four SJA1000 CAN controllers from 2002 under heavy bus |
585 | load without any problems ... | 586 | load without any problems ... |
586 | 587 | ||
587 | 6.4 currently supported CAN hardware (September 2007) | 588 | 6.4 The virtual CAN driver (vcan) |
589 | |||
590 | Similar to the network loopback devices, vcan offers a virtual local | ||
591 | CAN interface. A full qualified address on CAN consists of | ||
592 | |||
593 | - a unique CAN Identifier (CAN ID) | ||
594 | - the CAN bus this CAN ID is transmitted on (e.g. can0) | ||
595 | |||
596 | so in common use cases more than one virtual CAN interface is needed. | ||
597 | |||
598 | The virtual CAN interfaces allow the transmission and reception of CAN | ||
599 | frames without real CAN controller hardware. Virtual CAN network | ||
600 | devices are usually named 'vcanX', like vcan0 vcan1 vcan2 ... | ||
601 | When compiled as a module the virtual CAN driver module is called vcan.ko | ||
602 | |||
603 | Since Linux Kernel version 2.6.24 the vcan driver supports the Kernel | ||
604 | netlink interface to create vcan network devices. The creation and | ||
605 | removal of vcan network devices can be managed with the ip(8) tool: | ||
606 | |||
607 | - Create a virtual CAN network interface: | ||
608 | ip link add type vcan | ||
609 | |||
610 | - Create a virtual CAN network interface with a specific name 'vcan42': | ||
611 | ip link add dev vcan42 type vcan | ||
612 | |||
613 | - Remove a (virtual CAN) network interface 'vcan42': | ||
614 | ip link del vcan42 | ||
615 | |||
616 | The tool 'vcan' from the SocketCAN SVN repository on BerliOS is obsolete. | ||
617 | |||
618 | Virtual CAN network device creation in older Kernels: | ||
619 | In Linux Kernel versions < 2.6.24 the vcan driver creates 4 vcan | ||
620 | netdevices at module load time by default. This value can be changed | ||
621 | with the module parameter 'numdev'. E.g. 'modprobe vcan numdev=8' | ||
622 | |||
623 | 6.5 currently supported CAN hardware | ||
588 | 624 | ||
589 | On the project website http://developer.berlios.de/projects/socketcan | 625 | On the project website http://developer.berlios.de/projects/socketcan |
590 | there are different drivers available: | 626 | there are different drivers available: |
@@ -603,7 +639,7 @@ solution for a couple of reasons: | |||
603 | 639 | ||
604 | Please check the Mailing Lists on the berlios OSS project website. | 640 | Please check the Mailing Lists on the berlios OSS project website. |
605 | 641 | ||
606 | 6.5 todo (September 2007) | 642 | 6.6 todo |
607 | 643 | ||
608 | The configuration interface for CAN network drivers is still an open | 644 | The configuration interface for CAN network drivers is still an open |
609 | issue that has not been finalized in the socketcan project. Also the | 645 | issue that has not been finalized in the socketcan project. Also the |