[PATCH v8 4/8] net: dsa: allow rcv() and xmit() to be optional

[Vladimir Oltean]

On Tue, Nov 29, 2022 at 02:53:15PM -0800, Tim Harvey wrote:
> On Mon, Nov 28, 2022 at 7:58 AM Tom Rini <trini at konsulko.com> wrote:
> >
> > On Thu, Oct 27, 2022 at 05:49:33PM -0700, Tim Harvey wrote:
> >
> > > Allow rcv() and xmit() dsa driver ops to be optional in case a driver
> > > does not care to mangle a packet as in U-Boot only one network port is
> > > enabled at a time and thus no packet mangling is necessary.
> > >
> > > Suggested-by: Vladimir Oltean <vladimir.oltean at nxp.com>
> > > Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> > > Reviewed-by: Vladimir Oltean <vladimir.oltean at nxp.com>
> > > Reviewed-by: Fabio Estevam <festevam at denx.de>
> >
> > This causes:
> > FAILED test/py/tests/test_ut.py::test_ut[ut_dm_dm_test_dsa] - AssertionError: assert False
> >
> > In sandbox, and I don't know if the test or the code is wrong.
> >
> 
> Tom,
> 
> I'm not familiar at all with U-Boot's sandbox or unit test
> infrastructure and am trying to learn.
> 
> I've figured out how to build sandbox and run the dm_test_dsa
> (./u-boot -T -c "ut dm dsa") and see the same failure as you but I
> don't understand how to debug this as it seems prints I add in
> dsa_port_send and dsa_port_recv (which is what this patch modifies)
> don't get print when run from the test infrastructure.
> 
> When I boot u-boot sandbox (./u-boot) I don't see any network devices
> at all - perhaps I'm not booting sandbox with dm or something? I need
> to understand what devices/drivers sandbox is using and how to
> recreate the network environment that the dm_test_dsa function is
> using which calls 'net_loop':
> 
>         net_ping_ip = string_to_ip("1.2.3.5");
> 
>         env_set("ethact", "eth2");
>         ut_assertok(net_loop(PING));
> 
>         env_set("ethact", "lan0");
>         ut_assertok(net_loop(PING));
>         env_set("ethact", "lan1");
>         ut_assertok(net_loop(PING));
> 
>         env_set("ethact", "");
> 
> Best Regards,
> 
> Tim

I use the following steps:

export KBUILD_OUTPUT=output-sandbox
make sandbox_defconfig NO_SDL=1
make -j 8 NO_SDL=1
$KBUILD_OUTPUT/u-boot -d $KBUILD_OUTPUT/arch/sandbox/dts/test.dtb
setenv ethact lan1
ping 1.2.3.5
ut dm dsa

In this case the problem with the patch is simple, sorry for not
noticing during review.

dsa_port_mangle_packet() changes the "length" variable. But if ops->xmit
exists, eth_get_ops(master)->send() is called with a bad (old) length,
the one pre mangling.