arm: davinci: USB ethernet

arm: davinci: USB ethernet

[Darryl]

We are currently using a DA850 eval board but will eventually use a 
custom board to interface host system to davinci using ethernet over 
USB.  We are using 2.6.37 with real-time patches, but a cursory look 
(have not been able to build yet) at 3.3-rc7 suggests that the issues 
noted below still exist.

There are currently two issues:

- Documentation/usb/hotplug.txt suggests that the drivers should be 
built as modules so that such things as loading drivers and, in this 
case, bringing up the interface, can ge moderated in user-space.  
However, though the code can be build modular, the drivers are never 
loaded.  I suspect that one or more of the several relevant configs (I 
see at least these:  USB_MUSB_HDRC, USB_MUSB_DA8XX_GLUE, USB_GADGET, 
USB_ETH, USB_GPIO_VBUS, NOP_USB_XCEIV, USB_ETH_RNDIS, USB_OTG_UTILS) are 
required to be built in, but cannot seem to determine the correct ones.

- Even when compiling all the driver code built-in, neither the plug-in 
nor plug-out event is propagated to user space, again, so that the 
interface can be brought up.

I am happy enough to build-in the driver code, but I still need the 
ability to bring up the interface.  I know that I can use a call to
         call_usermodehelper
to get to use-space, but I'd still be faced with where that call would 
work best.

So, I'm wondering if you have suggestions regarding how to proceed.

Thanks,
Darryl

Re: arm: davinci: USB ethernet

[Greg KH]

On Mon, Mar 19, 2012 at 05:46:02AM -0500, Darryl wrote:
> We are currently using a DA850 eval board but will eventually use a
> custom board to interface host system to davinci using ethernet over
> USB.  We are using 2.6.37 with real-time patches, but a cursory look
> (have not been able to build yet) at 3.3-rc7 suggests that the
> issues noted below still exist.
> 
> There are currently two issues:
> 
> - Documentation/usb/hotplug.txt suggests that the drivers should be
> built as modules so that such things as loading drivers and, in this
> case, bringing up the interface, can ge moderated in user-space.
> However, though the code can be build modular, the drivers are never
> loaded.  I suspect that one or more of the several relevant configs
> (I see at least these:  USB_MUSB_HDRC, USB_MUSB_DA8XX_GLUE,
> USB_GADGET, USB_ETH, USB_GPIO_VBUS, NOP_USB_XCEIV, USB_ETH_RNDIS,
> USB_OTG_UTILS) are required to be built in, but cannot seem to
> determine the correct ones.

Do you have a userspace tool that will automatically load the proper
modules when they show up?

As for unwinding the .config issues, you will have to do this, based on
your own settings, not much we can do here.

> - Even when compiling all the driver code built-in, neither the
> plug-in nor plug-out event is propagated to user space, again, so
> that the interface can be brought up.

How do you know it isn't showing up?  What are you using to watch for
it?  Are you using udev?  Something else?  devtmpfs?

greg k-h

Re: arm: davinci: USB ethernet

[ddegraff]

On 03/20/2012 08:58 AM, Greg KH wrote:
> On Mon, Mar 19, 2012 at 05:46:02AM -0500, Darryl wrote:
>> We are currently using a DA850 eval board but will eventually use a
>> custom board to interface host system to davinci using ethernet over
>> USB.  We are using 2.6.37 with real-time patches, but a cursory look
>> (have not been able to build yet) at 3.3-rc7 suggests that the
>> issues noted below still exist.
>>
>> There are currently two issues:
>>
>> - Documentation/usb/hotplug.txt suggests that the drivers should be
>> built as modules so that such things as loading drivers and, in this
>> case, bringing up the interface, can ge moderated in user-space.
>> However, though the code can be build modular, the drivers are never
>> loaded.  I suspect that one or more of the several relevant configs
>> (I see at least these:  USB_MUSB_HDRC, USB_MUSB_DA8XX_GLUE,
>> USB_GADGET, USB_ETH, USB_GPIO_VBUS, NOP_USB_XCEIV, USB_ETH_RNDIS,
>> USB_OTG_UTILS) are required to be built in, but cannot seem to
>> determine the correct ones.
> Do you have a userspace tool that will automatically load the proper
> modules when they show up?
Busybox's mdev is currently intended for that.  I've used udev for other 
projects, but we have a very limited space here.
More important at the moment, however, is getting notifications in 
userspace.
>
> As for unwinding the .config issues, you will have to do this, based on
> your own settings, not much we can do here.
It is my hope that the developers from TI and MonteVista will weigh in 
since I have, so far, unsuccessfully unwound the interactions.
>
>> - Even when compiling all the driver code built-in, neither the
>> plug-in nor plug-out event is propagated to user space, again, so
>> that the interface can be brought up.
> How do you know it isn't showing up?  What are you using to watch for
> it?  Are you using udev?  Something else?  devtmpfs?
As noted above, mdev, which is set as the userspace hotplug script (via 
echo its full path to /proc/sys/kernel/hotplug) which I have slightly 
modified to just log that it is being run, and see no output messages.
>
> greg k-h
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Re: arm: davinci: USB ethernet

[Greg KH]

On Tue, Mar 20, 2012 at 10:52:38AM -0500, ddegraff wrote:
> 
> 
> On 03/20/2012 08:58 AM, Greg KH wrote:
> >On Mon, Mar 19, 2012 at 05:46:02AM -0500, Darryl wrote:
> >>We are currently using a DA850 eval board but will eventually use a
> >>custom board to interface host system to davinci using ethernet over
> >>USB.  We are using 2.6.37 with real-time patches, but a cursory look
> >>(have not been able to build yet) at 3.3-rc7 suggests that the
> >>issues noted below still exist.
> >>
> >>There are currently two issues:
> >>
> >>- Documentation/usb/hotplug.txt suggests that the drivers should be
> >>built as modules so that such things as loading drivers and, in this
> >>case, bringing up the interface, can ge moderated in user-space.
> >>However, though the code can be build modular, the drivers are never
> >>loaded.  I suspect that one or more of the several relevant configs
> >>(I see at least these:  USB_MUSB_HDRC, USB_MUSB_DA8XX_GLUE,
> >>USB_GADGET, USB_ETH, USB_GPIO_VBUS, NOP_USB_XCEIV, USB_ETH_RNDIS,
> >>USB_OTG_UTILS) are required to be built in, but cannot seem to
> >>determine the correct ones.
> >Do you have a userspace tool that will automatically load the proper
> >modules when they show up?
> Busybox's mdev is currently intended for that.  I've used udev for
> other projects, but we have a very limited space here.

udev really is too big?  My cheap wireless router runs udev, I'm amazed
that people really feel that mdev is a proper replacement.

Odds are, you really don't need mdev, just use devtmpfs and be done with
it.

Anyway, as you are stuck with an old kernel release, I suggest you get
support from your vendor, they are the only ones that can help you out
here.

best of luck,

greg k-h