Re: [Qemu-devel] Writing a CAN driver for QEMU

[Rempel, Cynthia]

>> The RTEMS development community is considering having a Google Summer
>> of Code student test LinCAN on a simulated RTEMS target board using
>> QEMU, and have some questions:
>>
>> 1. What guidelines should the student follow when writing the device > 
>> simulation, so the device simulation will be "upstreamed"/accepted by
>> the QEMU project?
>> 2. Is there additional documentation on how to write a device
>> simulation?

>Unfortunately there is not much documentation.

Would following the guidance in:
http://lists.gnu.org/archive/html/qemu-devel/2011-07/msg00842.html
increase the probability the device simulation would be committed to qemu?

>Would this interact with
>something in the host (e.g. emulating the sensors)?  Or is it like USB
>where QEMU has emulation of both controllers and devices (e.g. tablets
>or storage)?

we want to be able to verify a guest OS's CAN driver has been integrated 
properly and is sending CAN packets... 

Perhaps along the lines of two calls:
qemu-system-arm -hda linux1.img -can student-implemented-device
qemu-system-arm -hda linux2.img -can student-implemented-device

Then using a network protocol analyzer (such as Wireshark) with a custom filter 
to recognize CAN packets,
OR
qemu-system-arm -hda linux1.img -can student-implemented-device
then attaching a real CAN device to the host computer and verifying that the 
output is being recognized be real hardware.

Whichever is more feasible to implement...

>There are lots of different devices in QEMU; a student with good code
>reading abilities should be able to find what he needs, but if you are
>writing an entire emulation subsystem it's going to be a lot of work.
Is it feasible to implement an emulation of a CAN device as a Google Summer of 
Code project? If so, what would be a feasible CAN device to implement? If not, 
would having the student hook up a real CAN device to an emulated guest OS be 
feasible to implement as a Google Summer of Code project?

>> 3. Could we get a co-mentor from qemu-devel to help the student with
>> technical questions, or if not, would this mailing list be willing to
>> help us out?
>I don't know if someone is available to mentor the project, but the
>mailing list would surely be of help.
Thanks we really appreciate all the help :)

>Paolo