net: dsa: b53: do not enable EEE on bcm63xx

commit 1237c2d upstream.

BCM63xx internal switches do not support EEE, but provide multiple RGMII
ports where external PHYs may be connected. If one of these PHYs are EEE
capable, we may try to enable EEE for the MACs, which then hangs the
system on access of the (non-existent) EEE registers.

Fix this by checking if the switch actually supports EEE before
attempting to configure it.

Fixes: 22256b0 ("net: dsa: b53: Move EEE functions to b53")
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Tested-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Link: https://patch.msgid.link/20250602193953.1010487-2-jonas.gorski@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 3fbe3f4c57fda09f32e13fa05f53a0cc6f500619)
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>

Author: KanjiMonster

drivers/net/dsa/b53/b53_common.c

@@ -2378,6 +2378,9 @@ int b53_eee_init(struct dsa_switch *ds, int port, struct phy_device *phy)
 {
 	int ret;
 
+	if (!b53_support_eee(ds, port))
+		return 0;
+
 	ret = phy_init_eee(phy, false);
 	if (ret)
 		return 0;
@@ -2392,7 +2395,7 @@ bool b53_support_eee(struct dsa_switch *ds, int port)
 {
 	struct b53_device *dev = ds->priv;
 
-	return !is5325(dev) && !is5365(dev);
+	return !is5325(dev) && !is5365(dev) && !is63xx(dev);
 }
 EXPORT_SYMBOL(b53_support_eee);