Wolfgang Grandegger wrote:

Oliver Hartkopp wrote:

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Wolfgang Grandegger wrote:

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Sascha Hauer wrote:

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On Fri, Jul 24, 2009 at 04:55:02PM +0200, Wolfgang Grandegger wrote:

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+	kfree_skb(skb);

Support for echo skb using can_put/get_echo_skb() is missing. It should
not be a big deal to add it.

In fact it's not missing, but the hardware is configured to receive its
own packets, so this isn't needed.

But the user may disable IFF_ECHO, which should be handled somehow.

Really?

IMO IFF_ECHO indicates the capability of the network driver to perform the MAC
layer frame echo on driver level.

Only when you have a CAN driver that does not have this capability (the 'bad'
non default case) this flag is cleared.

There is no need to provide a mode that can switch this functionality 'on' and
'off'. IFF_ECHO is just an indication provided by the driver.

When the FlexCAN controller can 'receive' a sent frame, so that it reflects
the correct message order on the bus, this is perfect.

In this case Sascha should set the IFF_ECHO flag and he's done.

I thought the user can toggle the IFF_ECHO flag with the "ip" utility,
but obviously I'm wrong.

AFAIK the only driver that currently allows to switch this flag is the vcan
driver - but this is for testing purposes only and can be configured by the
module commandline.

I assume having the echo functionality runtime configurable is only effort and
complicates the driver ...

Best regards,
Oliver