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Date:   Mon, 26 Nov 2018 22:07:59 +0200
From:   Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
To:     Grygorii Strashko <grygorii.strashko@ti.com>
Cc:     "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Sekhar Nori <nsekhar@ti.com>, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org
Subject: Re: [PATCH net-next] net: ethernet: ti: cpsw: drop vid0
 configuration in dual_mac modey
Message-ID: <20181126200757.GB23230@khorivan>
Mail-Followup-To: Grygorii Strashko <grygorii.strashko@ti.com>,
        "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Sekhar Nori <nsekhar@ti.com>, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org
References: <20181125234626.28474-1-grygorii.strashko@ti.com>
 <20181126162644.GA23230@khorivan>
 <7f2c5e66-3b42-f921-c52d-236f5adc44bf@ti.com>
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On Mon, Nov 26, 2018 at 12:57:20PM -0600, Grygorii Strashko wrote:
>
>
>On 11/26/18 10:26 AM, Ivan Khoronzhuk wrote:
>> On Sun, Nov 25, 2018 at 05:46:26PM -0600, Grygorii Strashko wrote:
>>> In dual_mac mode CPSW driver uses vid1 and vid2 by default to implement
>>> dual mac mode wich are used to configure pvids for each external ports.
>>> But, historicaly, it also adds vid0 to ALE table and sets "untag" bits for both
>>> ext. ports. As result, it's imposible to use priority tagged packets in
>>> dual mac mode.
>>>
>>> Hence, drop vid0 configuration in dual mac mode as it's not required for dual
>>> mac mode functionality and, this way, make it possible to use priority
>>> tagged packet in dual mac mode.
>> So, now it's enabled to be added via regular ndo.
>> I have similar change in mind, but was going to send it after
>> mcast/ucast, and - enabling same vlans patch...
>>
>> 2 things stopped me to add this:
>>
>> 1) Moving it to be enabled via regular call is Ok, but in dual mac mode
>> it causes overlaps, at least while vid deletion. So decided to wait till
>> same vlans series is applied.
>
>TI driver documentation mentions this restriction
>"While adding VLAN id to the eth interfaces,
>same VLAN id should not be added in both interfaces which will lead to VLAN
>forwarding and act as switch"
It's not accurate now.
This sw bug "acting like a switch" was fixed indirectly in LKML ).
And at least for upstream version, not TISDK, desc should be updated,
but better do this when it fixed completely and merged with TISDK.

I know about this "written" restriction
(for tiSDK, and it's not TRM after all ...),
it can be avoided and it's partly avoided now ...

Also, for notice, while you add any of the vlans to any of
the ports, vlan0 is added to both of them.....restricted it or not.
Thanks to last changes in the driver it's not "acting like a switch"
The patch in question enables this in ndo, not me.

#ip link add link eth0 name eth0.400 type vlan id 400
[  326.538989] 8021q: 802.1Q VLAN Support v1.8
[  326.543217] 8021q: adding VLAN 0 to HW filter on device eth0
[  326.554645] 8021q: adding VLAN 0 to HW filter on device eth1
[  326.572236] net eth0: Adding vlanid 400 to vlan filter

I just propose to extend it later, when it's correct to do.
But if no harm (basically no harm, only if someone decides
to add vlan0 to both ports and then delete on one of them)
, at least you should take this into account.

>
>>
>> 2) Wanted implement somehow similar handling for single port boards
>> in one patch, not only for dual mac mode. This part was not clear and
>> not verified completely...
>>
>> So, if it's needed now, maybe better at this moment only remove
>> untag field? and remove vlan0 later, once other vlan changes applied.
>>
>> Say:
>>
>> cpsw_ale_add_vlan(cpsw->ale, cpsw->data.default_vlan,
>>  ????????? ALE_ALL_PORTS, 0, ALE_ALL_PORTS, 0);
>>
>> instead of:
>> cpsw_ale_add_vlan(cpsw->ale, cpsw->data.default_vlan,
>>  ????????? ALE_ALL_PORTS, ALE_ALL_PORTS, 0, 0);
>>
>
>This patch affects only dual_mac mode and in this mode adding vid0 by default is
>definitely make no sense in any case.
The above proposition is only to your change, only for dual-mac.

>
>>>
>>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
>>> ---
>>> drivers/net/ethernet/ti/cpsw.c | 7 ++-----
>>> 1 file changed, 2 insertions(+), 5 deletions(-)
>-- 
>regards,
>-grygorii

-- 
Regards,
Ivan Khoronzhuk