There're two code paths for setting up port 5:

mt7530_setup()
-> mt7530_setup_port5()

mt753x_phylink_mac_config()
-> mt753x_mac_config()
   -> mt7530_mac_config()
      -> mt7530_setup_port5()

Currently mt7530_setup_port5() from mt7530_setup() always runs. If port 5
is used as a CPU, DSA, or user port, mt7530_setup_port5() from
mt753x_phylink_mac_config() won't run. That is because priv->p5_interface
set on mt7530_setup_port5() will match state->interface on
mt753x_phylink_mac_config() which will stop running mt7530_setup_port5()
again.

Therefore, mt7530_setup_port5() will never run from
mt753x_phylink_mac_config().

Address this by not running mt7530_setup_port5() from mt7530_setup() if
port 5 is used as a CPU, DSA, or user port. This driver isn't in the
dsa_switches_apply_workarounds[] array so phylink will always be present.

For the cases of PHY muxing or the port being disabled, call
mt7530_setup_port5() from mt7530_setup(). mt7530_setup_port5() from
mt753x_phylink_mac_config() won't run when port 5 is disabled or used for
PHY muxing as port 5 won't be defined on the devicetree.

Do not set priv->p5_intf_sel to P5_DISABLED. It is already set to that when
"priv" is allocated.

Move setting the interface to a more specific location. It's supposed to be
overwritten if PHY muxing is detected.

Improve the comment which explains the process.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
---
 drivers/net/dsa/mt7530.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 8623742b35ee..069b3dfca6fa 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2308,16 +2308,15 @@ mt7530_setup(struct dsa_switch *ds)
 		return ret;
 
 	/* Setup port 5 */
-	priv->p5_intf_sel = P5_DISABLED;
-	interface = PHY_INTERFACE_MODE_NA;
-
 	if (!dsa_is_unused_port(ds, 5)) {
 		priv->p5_intf_sel = P5_INTF_SEL_GMAC5;
-		ret = of_get_phy_mode(dsa_to_port(ds, 5)->dn, &interface);
-		if (ret && ret != -ENODEV)
-			return ret;
 	} else {
-		/* Scan the ethernet nodes. look for GMAC1, lookup used phy */
+		/* Scan the ethernet nodes. Look for GMAC1, lookup the used PHY.
+		 * Set priv->p5_intf_sel to the appropriate value if PHY muxing
+		 * is detected.
+		 */
+		interface = PHY_INTERFACE_MODE_NA;
+
 		for_each_child_of_node(dn, mac_np) {
 			if (!of_device_is_compatible(mac_np,
 						     "mediatek,eth-mac"))
@@ -2348,6 +2347,8 @@ mt7530_setup(struct dsa_switch *ds)
 			of_node_put(phy_node);
 			break;
 		}
+
+		mt7530_setup_port5(ds, interface);
 	}
 
 #ifdef CONFIG_GPIOLIB
@@ -2358,8 +2359,6 @@ mt7530_setup(struct dsa_switch *ds)
 	}
 #endif /* CONFIG_GPIOLIB */
 
-	mt7530_setup_port5(ds, interface);
-
 	/* Flush the FDB table */
 	ret = mt7530_fdb_cmd(priv, MT7530_FDB_FLUSH, NULL);
 	if (ret < 0)
-- 
2.40.1

On Sat, Nov 18, 2023 at 03:31:55PM +0300, Arınç ÜNAL wrote:
> There're two code paths for setting up port 5:
> 
> mt7530_setup()
> -> mt7530_setup_port5()
> 
> mt753x_phylink_mac_config()
> -> mt753x_mac_config()
>    -> mt7530_mac_config()
>       -> mt7530_setup_port5()
> 
> Currently mt7530_setup_port5() from mt7530_setup() always runs. If port 5
> is used as a CPU, DSA, or user port, mt7530_setup_port5() from
> mt753x_phylink_mac_config() won't run. That is because priv->p5_interface
> set on mt7530_setup_port5() will match state->interface on
> mt753x_phylink_mac_config() which will stop running mt7530_setup_port5()
> again.
> 
> Therefore, mt7530_setup_port5() will never run from
> mt753x_phylink_mac_config().
> 
> Address this by not running mt7530_setup_port5() from mt7530_setup() if
> port 5 is used as a CPU, DSA, or user port. This driver isn't in the
> dsa_switches_apply_workarounds[] array so phylink will always be present.
> 
> For the cases of PHY muxing or the port being disabled, call
> mt7530_setup_port5() from mt7530_setup(). mt7530_setup_port5() from
> mt753x_phylink_mac_config() won't run when port 5 is disabled or used for
> PHY muxing as port 5 won't be defined on the devicetree.

... and this should state why this needs to happen - in other words,
the commit message should state why is it critical that port 5 is
always setup.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

On 18.11.2023 17:41, Russell King (Oracle) wrote:
> On Sat, Nov 18, 2023 at 03:31:55PM +0300, Arınç ÜNAL wrote:
>> There're two code paths for setting up port 5:
>>
>> mt7530_setup()
>> -> mt7530_setup_port5()
>>
>> mt753x_phylink_mac_config()
>> -> mt753x_mac_config()
>>     -> mt7530_mac_config()
>>        -> mt7530_setup_port5()
>>
>> Currently mt7530_setup_port5() from mt7530_setup() always runs. If port 5
>> is used as a CPU, DSA, or user port, mt7530_setup_port5() from
>> mt753x_phylink_mac_config() won't run. That is because priv->p5_interface
>> set on mt7530_setup_port5() will match state->interface on
>> mt753x_phylink_mac_config() which will stop running mt7530_setup_port5()
>> again.
>>
>> Therefore, mt7530_setup_port5() will never run from
>> mt753x_phylink_mac_config().
>>
>> Address this by not running mt7530_setup_port5() from mt7530_setup() if
>> port 5 is used as a CPU, DSA, or user port. This driver isn't in the
>> dsa_switches_apply_workarounds[] array so phylink will always be present.
>>
>> For the cases of PHY muxing or the port being disabled, call
>> mt7530_setup_port5() from mt7530_setup(). mt7530_setup_port5() from
>> mt753x_phylink_mac_config() won't run when port 5 is disabled or used for
>> PHY muxing as port 5 won't be defined on the devicetree.
> 
> ... and this should state why this needs to happen - in other words,
> the commit message should state why is it critical that port 5 is
> always setup.

Actually, port 5 must not always be setup. With patch 7, I explain this
while preventing mt7530_setup_port5() from running if port 5 is disabled.

Arınç

On Sat, Dec 02, 2023 at 11:36:03AM +0300, Arınç ÜNAL wrote:
> On 18.11.2023 17:41, Russell King (Oracle) wrote:
> > > For the cases of PHY muxing or the port being disabled, call
> > > mt7530_setup_port5() from mt7530_setup(). mt7530_setup_port5() from
> > > mt753x_phylink_mac_config() won't run when port 5 is disabled or used for
> > > PHY muxing as port 5 won't be defined on the devicetree.
> > 
> > ... and this should state why this needs to happen - in other words,
> > the commit message should state why is it critical that port 5 is
> > always setup.
> 
> Actually, port 5 must not always be setup. With patch 7, I explain this
> while preventing mt7530_setup_port5() from running if port 5 is disabled.
> 
> Arınç

Then change that last paragraph. You could say something like this:

To keep the cases where port 5 isn't controlled by phylink working as
before, we need to preserve the mt7530_setup_port5() call from mt7530_setup().

I think it's a case of saying too much, which sparks too many unresolved
questions in the reader's mind, which are irrelevant for the purpose of
this specific change: eliminating the overlap between DSA's setup() time
and phylink.

On 7.12.2023 21:03, Vladimir Oltean wrote:
> On Sat, Dec 02, 2023 at 11:36:03AM +0300, Arınç ÜNAL wrote:
>> On 18.11.2023 17:41, Russell King (Oracle) wrote:
>>>> For the cases of PHY muxing or the port being disabled, call
>>>> mt7530_setup_port5() from mt7530_setup(). mt7530_setup_port5() from
>>>> mt753x_phylink_mac_config() won't run when port 5 is disabled or used for
>>>> PHY muxing as port 5 won't be defined on the devicetree.
>>>
>>> ... and this should state why this needs to happen - in other words,
>>> the commit message should state why is it critical that port 5 is
>>> always setup.
>>
>> Actually, port 5 must not always be setup. With patch 7, I explain this
>> while preventing mt7530_setup_port5() from running if port 5 is disabled.
>>
>> Arınç
> 
> Then change that last paragraph. You could say something like this:
> 
> To keep the cases where port 5 isn't controlled by phylink working as
> before, we need to preserve the mt7530_setup_port5() call from mt7530_setup().
> 
> I think it's a case of saying too much, which sparks too many unresolved
> questions in the reader's mind, which are irrelevant for the purpose of
> this specific change: eliminating the overlap between DSA's setup() time
> and phylink.

Will do, thanks.