mirror of
https://github.com/qemu/qemu.git
synced 2024-12-15 23:43:31 +08:00
6fe6d6c9a9
The company 'Arm' went through a rebranding some years back involving a recapitalization from 'ARM' to 'Arm'. As a result our documentation is a bit inconsistent between the two forms. It's not worth trying to update everywhere in QEMU, but it's easy enough to make docs/ consistent. Note that "ARMv8" and similar architecture names, and older CPU names like "ARM926" still retain all-caps. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com> Message-id: 20200309215818.2021-6-peter.maydell@linaro.org
108 lines
4.2 KiB
Plaintext
108 lines
4.2 KiB
Plaintext
QEMU CAN bus emulation support
|
|
==============================
|
|
|
|
The CAN bus emulation provides mechanism to connect multiple
|
|
emulated CAN controller chips together by one or multiple CAN busses
|
|
(the controller device "canbus" parameter). The individual busses
|
|
can be connected to host system CAN API (at this time only Linux
|
|
SocketCAN is supported).
|
|
|
|
The concept of busses is generic and different CAN controllers
|
|
can be implemented for it but at this time only SJA1000 chip
|
|
controller is implemented.
|
|
|
|
The PCI addon card hardware has been selected as the first CAN
|
|
interface to implement because such device can be easily connected
|
|
to systems with different CPU architectures (x86, PowerPC, Arm, etc.).
|
|
|
|
The project has been initially started in frame of RTEMS GSoC 2013
|
|
slot by Jin Yang under our mentoring The initial idea was to provide generic
|
|
CAN subsystem for RTEMS. But lack of common environment for code and RTEMS
|
|
testing lead to goal change to provide environment which provides complete
|
|
emulated environment for testing and RTEMS GSoC slot has been donated
|
|
to work on CAN hardware emulation on QEMU.
|
|
|
|
Examples how to use CAN emulation
|
|
=================================
|
|
|
|
When QEMU with CAN PCI support is compiled then one of the next
|
|
CAN boards can be selected
|
|
|
|
(1) CAN bus Kvaser PCI CAN-S (single SJA1000 channel) boad. QEMU startup options
|
|
-object can-bus,id=canbus0
|
|
-device kvaser_pci,canbus=canbus0
|
|
Add "can-host-socketcan" object to connect device to host system CAN bus
|
|
-object can-host-socketcan,id=canhost0,if=can0,canbus=canbus0
|
|
|
|
(2) CAN bus PCM-3680I PCI (dual SJA1000 channel) emulation
|
|
-object can-bus,id=canbus0
|
|
-device pcm3680_pci,canbus0=canbus0,canbus1=canbus0
|
|
|
|
another example:
|
|
-object can-bus,id=canbus0
|
|
-object can-bus,id=canbus1
|
|
-device pcm3680_pci,canbus0=canbus0,canbus1=canbus1
|
|
|
|
(3) CAN bus MIOe-3680 PCI (dual SJA1000 channel) emulation
|
|
-device mioe3680_pci,canbus0=canbus0
|
|
|
|
|
|
The ''kvaser_pci'' board/device model is compatible with and has been tested with
|
|
''kvaser_pci'' driver included in mainline Linux kernel.
|
|
The tested setup was Linux 4.9 kernel on the host and guest side.
|
|
Example for qemu-system-x86_64:
|
|
|
|
qemu-system-x86_64 -accel kvm -kernel /boot/vmlinuz-4.9.0-4-amd64 \
|
|
-initrd ramdisk.cpio \
|
|
-virtfs local,path=shareddir,security_model=none,mount_tag=shareddir \
|
|
-object can-bus,id=canbus0 \
|
|
-object can-host-socketcan,id=canhost0,if=can0,canbus=canbus0 \
|
|
-device kvaser_pci,canbus=canbus0 \
|
|
-nographic -append "console=ttyS0"
|
|
|
|
Example for qemu-system-arm:
|
|
|
|
qemu-system-arm -cpu arm1176 -m 256 -M versatilepb \
|
|
-kernel kernel-qemu-arm1176-versatilepb \
|
|
-hda rpi-wheezy-overlay \
|
|
-append "console=ttyAMA0 root=/dev/sda2 ro init=/sbin/init-overlay" \
|
|
-nographic \
|
|
-virtfs local,path=shareddir,security_model=none,mount_tag=shareddir \
|
|
-object can-bus,id=canbus0 \
|
|
-object can-host-socketcan,id=canhost0,if=can0,canbus=canbus0 \
|
|
-device kvaser_pci,canbus=canbus0,host=can0 \
|
|
|
|
The CAN interface of the host system has to be configured for proper
|
|
bitrate and set up. Configuration is not propagated from emulated
|
|
devices through bus to the physical host device. Example configuration
|
|
for 1 Mbit/s
|
|
|
|
ip link set can0 type can bitrate 1000000
|
|
ip link set can0 up
|
|
|
|
Virtual (host local only) can interface can be used on the host
|
|
side instead of physical interface
|
|
|
|
ip link add dev can0 type vcan
|
|
|
|
The CAN interface on the host side can be used to analyze CAN
|
|
traffic with "candump" command which is included in "can-utils".
|
|
|
|
candump can0
|
|
|
|
Links to other resources
|
|
========================
|
|
|
|
(1) Repository with development branch can-pci at Czech Technical University
|
|
https://gitlab.fel.cvut.cz/canbus/qemu-canbus
|
|
(2) GitHub repository with can-pci and our other changes included
|
|
https://gitlab.fel.cvut.cz/canbus/qemu-canbus
|
|
(3) RTEMS page describing project
|
|
https://devel.rtems.org/wiki/Developer/Simulators/QEMU/CANEmulation
|
|
(4) RTLWS 2015 article about the project and its use with CANopen emulation
|
|
http://rtime.felk.cvut.cz/publications/public/rtlws2015-qemu-can.pdf
|
|
Slides
|
|
http://rtime.felk.cvut.cz/publications/public/rtlws2015-qemu-can-slides.pdf
|
|
(5) Linux SocketCAN utilities
|
|
https://github.com/linux-can/can-utils/
|