i.MX6 SabreLite FlexCAN emulation for QEMU progress/working

i.MX6 SabreLite FlexCAN emulation for QEMU progress/working

[Pavel Pisa]

Hello Marc and others,

Matyas Bobek has implemented FlexCAN emulation for i.MX6
targets in the frame of his bachelor thesis

  https://dspace.cvut.cz/bitstream/handle/10467/122654/F3-BP-2025-Bobek-Matyas-BP_Bobek_FlexCAN_final_4.pdf

with reviews there

  https://dspace.cvut.cz/handle/10467/122779

Please, if you have problems to access documents, try that later,
our large archive with theses and publications is under
"AI" scrape-bots attacks almost permanently... or send me note
and I send the document directly.

The project continues and on base of Marc Kleine-Budde
review, Matyas Bobek has implemented timestamping
which should ensure correct messages ordering
even if FIFO mode is not used in the drivers,
Linux driver default case. There is even workaround
to advance timestamp if the the QEMU virtual time
is too coarse to provide unique values for for
too fast delivered messages through virtual bus
without real bits serialization.

The actual code is available on the "flexcan"
branch of the repository

  https://gitlab.fel.cvut.cz/bobekmat/qemu-flexcan

The clean, minimal patches sequence will be prepared
for review for the proposal for inclusion into QEMU
mainline, hopefully soon.

In longer term perspective, I have interrest in i.MX8
and other FlexCAN variants with FD support, etc.
I do not know if Mr. Bobek will have time and interest
to continue in this direction. I can offer that as the
another thesis or can offer that as summer job
etc. But latter would need some funding for students
motivation and their time compensation and I have had
never and do not have any QEMU related project for such
funding now and even minimal chance is even in future
for other than CTU CAN FD IP core where we support
silicon and FPGA products. So no timing, chances,
estimates for something beyond i.MX6 FlexCAN. 

Best wishes, 

                Pavel

                Pavel Pisa
    phone:      +420 603531357
    e-mail:     pisa@cmp.felk.cvut.cz
    Department of Control Engineering FEE CVUT
    Karlovo namesti 13, 121 35, Prague 2
    university: http://control.fel.cvut.cz/
    personal:   http://cmp.felk.cvut.cz/~pisa
    social:     https://social.kernel.org/ppisa
    projects:   https://www.openhub.net/accounts/ppisa
    CAN related:http://canbus.pages.fel.cvut.cz/
    RISC-V education: https://comparch.edu.cvut.cz/
    Open Technologies Research Education and Exchange Services
    https://gitlab.fel.cvut.cz/otrees/org/-/wikis/home

Re: i.MX6 SabreLite FlexCAN emulation for QEMU progress/working

[Marc Kleine-Budde]

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On 10.07.2025 12:58:05, Pavel Pisa wrote:
> Hello Marc and others,
> 
> Matyas Bobek has implemented FlexCAN emulation for i.MX6
> targets in the frame of his bachelor thesis
> 
>   https://dspace.cvut.cz/bitstream/handle/10467/122654/F3-BP-2025-Bobek-Matyas-BP_Bobek_FlexCAN_final_4.pdf
> 
> with reviews there
> 
>   https://dspace.cvut.cz/handle/10467/122779
> 
> Please, if you have problems to access documents, try that later,
> our large archive with theses and publications is under
> "AI" scrape-bots attacks almost permanently... or send me note
> and I send the document directly.
> 
> The project continues and on base of Marc Kleine-Budde
> review, Matyas Bobek has implemented timestamping
> which should ensure correct messages ordering
> even if FIFO mode is not used in the drivers,
> Linux driver default case. There is even workaround
> to advance timestamp if the the QEMU virtual time
> is too coarse to provide unique values for for
> too fast delivered messages through virtual bus
> without real bits serialization.

Nice! Good work!

> The actual code is available on the "flexcan"
> branch of the repository
> 
>   https://gitlab.fel.cvut.cz/bobekmat/qemu-flexcan
> 
> The clean, minimal patches sequence will be prepared
> for review for the proposal for inclusion into QEMU
> mainline, hopefully soon.
> 
> In longer term perspective, I have interrest in i.MX8
> and other FlexCAN variants with FD support, etc.
> I do not know if Mr. Bobek will have time and interest
> to continue in this direction. I can offer that as the
> another thesis or can offer that as summer job
> etc. But latter would need some funding for students
> motivation and their time compensation and I have had
> never and do not have any QEMU related project for such
> funding now and even minimal chance is even in future
> for other than CTU CAN FD IP core where we support
> silicon and FPGA products. So no timing, chances,
> estimates for something beyond i.MX6 FlexCAN. 

ACK, I think getting things mainline is more important than CAN-FD
support.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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