diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-10-28 16:26:12 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-10-28 16:26:12 +0100 |
commit | 7a9787e1eba95a166265e6a260cf30af04ef0a99 (patch) | |
tree | e730a4565e0318140d2fbd2f0415d18a339d7336 /Documentation/networking/can.txt | |
parent | 41b9eb264c8407655db57b60b4457fe1b2ec9977 (diff) | |
parent | 0173a3265b228da319ceb9c1ec6a5682fd1b2d92 (diff) |
Merge commit 'v2.6.28-rc2' into x86/pci-ioapic-boot-irq-quirks
Diffstat (limited to 'Documentation/networking/can.txt')
-rw-r--r-- | Documentation/networking/can.txt | 48 |
1 files changed, 42 insertions, 6 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index 641d2afacffa..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 @@ -186,7 +187,7 @@ solution for a couple of reasons: The Linux network devices (by default) just can handle the transmission and reception of media dependent frames. Due to the - arbritration on the CAN bus the transmission of a low prio CAN-ID + arbitration on the CAN bus the transmission of a low prio CAN-ID may be delayed by the reception of a high prio CAN frame. To reflect the correct* traffic on the node the loopback of the sent data has to be performed right after a successful transmission. If @@ -481,7 +482,7 @@ solution for a couple of reasons: - stats_timer: To calculate the Socket CAN core statistics (e.g. current/maximum frames per second) this 1 second timer is invoked at can.ko module start time by default. This timer can be - disabled by using stattimer=0 on the module comandline. + disabled by using stattimer=0 on the module commandline. - debug: (removed since SocketCAN SVN r546) @@ -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 |