Messages in this thread | | | Date | Mon, 23 Feb 2009 10:55:47 +0100 | From | Patrick McHardy <> | Subject | Re: [PATCH 3/8] can: CAN Network device driver and SYSFS interface |
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Wolfgang Grandegger wrote: > Patrick McHardy wrote: >> Is sysfs really the best choice for this? It has the usual problems, >> you can't change multiple parameters at once atomically. Now, I don't >> know whether this is actually (and currently) a problem for CAN, but >> given that we already have a generic netlink interface for creating >> network interfaces that can easily support this, what are the reasons >> for adding a new interface instead of using the existing one? > > You refer to the API described at http://lwn.net/Articles/236919/, I > assume.
Exactly.
> Well, I know that netlink is used to define routes in the kernel > or VLANs but I was not aware that it can also be used to configure real > network devices. What a pity. At a first glance, I could also be used > for CAN, of course. There are the following requirements: > > 1. Set and get CAN device properties like bit-rate and controller mode. > 2. Show CAN bus state (active, error-passive or bus-off). > 3. Get device constants like clock frequency and bit-timing parameters. > 4. Dump CAN device statistics. > 5. Trigger device restart if CAN bus-off state has been detected. > > Not sure yet, if the interface if good for all purposes. Especially > point 5. might be better handled by an IOCTL.
The first points sound pretty regular. The last one - just triggering it is no problem of course, but since I don't know how the detection works, I can't really tell whether its suitable.
> And we need a user space > tool, e.g. canconfig, to handle the user requests and communicate with > the kernel side.
Thats pretty standard :)
> We will follow that promising route. Any further help > or link is appreciated. Thanks.
It should be quite easy to move your interface on top. A few examples that might be useful are vlan, ip_gre and macvlan.
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