netdev - Re: b53 tags on bpi-r1 (bcm53125)

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Message-ID: <514a187b-cd3d-a15c-cd28-60b0b2d49dcd@scram.de>
Date:   Mon, 18 Dec 2017 11:44:51 +0100
From:   Jochen Friedrich <jochen@...am.de>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     netdev@...r.kernel.org
Subject: Re: b53 tags on bpi-r1 (bcm53125)

Hi Florian,

unfortunately, this doesn't make any difference.

Just out of curiosity, BPI-R1 has pull-down resistors on LED6 and 7 
(MII_MODE0/1). However, the public available 53125U sheet doesn't 
document these pins:

LED[6] IMP_MODE[0] Pull-up Active low (since IMP Mode is not used)
LED[7] IMP_MODE[1] Pull-up Active low (since IMP Mode is not used)

Is this MII mode maybe incompatible with Broadcom tags?

Thanks,
Jochen

Am 15.12.2017 um 02:55 schrieb Florian Fainelli:
> Hi Jochen,
>
> On 11/23/2017 11:14 AM, Jochen Friedrich wrote:
>> Hi Florian,
>>
>>> With Broadcom tags (or any type of switch tagging protocol), eth0
>>> becomes a conduit interface and no longer a "normal" network device for
>>> applications/socket to use. This means that if you were obtaining an IP
>>> address through a DHCP client using e.g: dhclient eth0, this now needs
>>> to be replaced using dhclient lan1 for instance.
>> Yes, that's what I would expect.
>>
>>> If you use the per-port network devices, do you actually see Broadcom
>>> tags coming out of these interfaces, or is it just when you use eth0
>>> like what you used before that you see that happening?
>> For outgoing Packet, I see the tags on eth0, that's expected, but also
>> an a laptop connected to any of the external ports (no matter which one,
>> wan or lan1-4).
>> Incoming packets are seen on eth0 untagged and don't get forwarded to
>> the corresponding child Interface.>
>> So it seems the switch operates in dumb forwarding mode.
> Humm, what if you comment that part from b53_set_forwarding:
>
>          b53_read8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, &mgmt);
>          mgmt |= B53_MII_DUMB_FWDG_EN;
>          b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, mgmt);
>
> does this help?
>
>> I also tried a pull down on LED Port 0 (mii_dumb_fwdg_en), but the
>> switch still remains in dumb mode. However, I would have to double check
>> I picked the correct pin, the Bpi-r1 schematics is not completely error
>> free :-(.
>>
>> Thanks, Jochen