Re: XEN CAN Driver

[Jonas Blixt <jonas.blixt@xxxxxxxx>]

> Is the data being sent/received by the domU put directly onto the
> rings, or is it mapped via grant mappings by dom0?
>
> Are all the requests on the rings of the same size?

The data sent from both domU and dom0 are written directly to the rings
 and all requests/responses (CAN Frames) have the same, fixed, size.

> Are the single requests/responses acknowledged by the other side
> (I guess "yes", as I presume this is what you are referring to as
> "flow control")?

Yes, sending a frame from domU will trigger the interrupt handler in dom0
and similarly the other way around.

Frames originating from the physical interface is bound to a relatively
low baud rate but the other way around is only limited by the performance
of the ring buffers. To cope with this we hade to call 'netif_stop_queue' 
in the front end driver to stall the applications sending frames.
And when there is space available in the ring 'netif_wake_queue' to
resume.


Jonas