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Message-ID: <5acf02b1-8af4-4259-9ce1-c7c7ae00ae9d@arinc9.com>
Date: Sat, 27 Apr 2024 18:43:03 +0300
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Subject: Re: [PATCH net-next] net: dsa: mt7530: do not set MT7530_P5_DIS when
 PHY muxing is being used
To: Andrew Lunn <andrew@lunn.ch>
Cc: Daniel Golle <daniel@makrotopia.org>, DENG Qingfang <dqfext@gmail.com>,
 Sean Wang <sean.wang@mediatek.com>, Florian Fainelli <f.fainelli@gmail.com>,
 Vladimir Oltean <olteanv@gmail.com>, "David S. Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>,
 Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
 Matthias Brugger <matthias.bgg@gmail.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
 netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org
References: <20240427-for-netnext-mt7530-do-not-disable-port5-when-phy-muxing-v1-1-793cdf9d7707@arinc9.com>
 <7c476e63-5747-4128-af97-13edc252a263@lunn.ch>
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From: =?UTF-8?B?QXLEsW7DpyDDnE5BTA==?= <arinc.unal@arinc9.com>
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On 27.04.2024 16:31, Andrew Lunn wrote:
> On Sat, Apr 27, 2024 at 02:24:42PM +0300, Arınç ÜNAL via B4 Relay wrote:
>> From: Arınç ÜNAL <arinc.unal@arinc9.com>
>>
>> When the PHY muxing feature is in use, port 5 won't be defined in the
>> device tree. Because of this, the type member of the dsa_port structure for
>> this port will be assigned DSA_PORT_TYPE_UNUSED. The dsa_port_setup()
>> function calls ds->ops->port_disable() when the port type is
>> DSA_PORT_TYPE_UNUSED.
>>
>> The MT7530_P5_DIS bit is unset when PHY muxing is being used.
>> mt7530_port_disable() which is assigned to ds->ops->port_disable() is
>> called afterwards. Currently, mt7530_port_disable() sets MT7530_P5_DIS
>> which breaks network connectivity when PHY muxing is being used.
>>
>> Therefore, do not set MT7530_P5_DIS when PHY muxing is being used.
>>
>> Fixes: 377174c5760c ("net: dsa: mt7530: move MT753X_MTRAP operations for MT7530")
>> Reported-by: Daniel Golle <daniel@makrotopia.org>
>> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
>> ---
>> Hello.
>>
>> I've sent this to net-next as the patch it fixes is on the current
>> development cycle.
>> ---
>>   drivers/net/dsa/mt7530.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
>> index 2b9f904a98f0..07b6da3ae97c 100644
>> --- a/drivers/net/dsa/mt7530.c
>> +++ b/drivers/net/dsa/mt7530.c
>> @@ -1220,7 +1220,7 @@ mt7530_port_disable(struct dsa_switch *ds, int port)
>>   	if (priv->id != ID_MT7530 && priv->id != ID_MT7621)
>>   		return;
>>   
>> -	if (port == 5)
>> +	if (port == 5 && priv->p5_mode == GMAC5)
>>   		mt7530_set(priv, MT753X_MTRAP, MT7530_P5_DIS);
> 
> 
> It might be worth a comment. It is not obvious that
> priv->p5_mode == GMAC5 means the PHY MUX is being used.
> mt7530_setup_port5() thinks it is sufficiently obscure that
> it comments each case.

priv->p5_mode == GMAC5 means PHY muxing is not being used. That is why
MT7530_P5_DIS is set when priv->p5_mode is GMAC5. Anyway, I believe this
proves your point.

Arınç