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Message-ID: <f9ad000a-2e42-4ddf-89a4-9a3ff452dc4b@arinc9.com>
Date: Sat, 6 Jan 2024 18:00:53 +0300
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Subject: Re: [PATCH net-next v2 6/7] net: dsa: mt7530: do not set
 priv->p5_interface on mt7530_setup_port5()
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To: Vladimir Oltean <olteanv@gmail.com>
Cc: Daniel Golle <daniel@makrotopia.org>,
 Landen Chao <Landen.Chao@mediatek.com>, DENG Qingfang <dqfext@gmail.com>,
 Sean Wang <sean.wang@mediatek.com>, Andrew Lunn <andrew@lunn.ch>,
 Florian Fainelli <f.fainelli@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>,
 Russell King <linux@armlinux.org.uk>,
 Frank Wunderlich <frank-w@public-files.de>,
 Bartel Eerdekens <bartel.eerdekens@constell8.be>, mithat.guner@xeront.com,
 erkin.bozoglu@xeront.com, netdev@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 linux-mediatek@lists.infradead.org
References: <20231227044347.107291-1-arinc.unal@arinc9.com>
 <20231227044347.107291-7-arinc.unal@arinc9.com>
 <20240104154241.rxjins4mi5zkbhia@skbuf>
From: =?UTF-8?B?QXLEsW7DpyDDnE5BTA==?= <arinc.unal@arinc9.com>
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On 4.01.2024 18:42, Vladimir Oltean wrote:
> On Wed, Dec 27, 2023 at 07:43:46AM +0300, Arınç ÜNAL wrote:
>> priv->p5_interface and priv->p6_interface are for use on the MT7531 switch.
>> They prevent the CPU ports of MT7531 to be configured again. They are
>> useless for MT7530. Therefore, remove setting priv->p5_interface for
>> MT7530.
>>
>> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
>> ---
> 
> What makes priv->p5_interface and priv->p6_interface useless for MT7530
> as you say? This code in mt753x_phylink_mac_config() seems executed
> regardless of switch family:
> 
> 	case 5:
> 		if (priv->p5_interface == state->interface)
> 			break;
> 
> 		if (mt753x_mac_config(ds, port, mode, state) < 0)
> 			goto unsupported;
> 
> 		if (priv->p5_intf_sel != P5_DISABLED)
> 			priv->p5_interface = state->interface;
> 		break;
> 	case 6:
> 		if (priv->p6_interface == state->interface)
> 			break;
> 
> 		mt753x_pad_setup(ds, state);
> 
> 		if (mt753x_mac_config(ds, port, mode, state) < 0)
> 			goto unsupported;
> 
> 		priv->p6_interface = state->interface;
> 		break;

This is also useless for non-MT7531 switches in the sense that it
unnecessarily prevents port 5 and 6 from being reconfigured. There's
nothing wrong with configuring them multiple times. These are the remains
of before phylink was implemented on this driver so the thought of changing
phy_interface_t on the fly was non existent. At that time, it was probably
made to apply to all switch models for convenience, as port 5 and 6 are CPU
ports so they're highly likely to be fixed links.

The reason I don't deal with this code block now is because I will get rid
of priv->p5_interface and priv->p6_interface when I also get rid of
priv->info->cpu_port_config() with a later patch.

Arınç