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-rw-r--r--Documentation/networking/can.txt44
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616 The tool 'vcan' from the SocketCAN SVN repository on BerliOS is obsolete.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