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From:   Lukasz Majewski <lukma@denx.de>
To:     Tristram.Ha@microchip.com, Eric Dumazet <edumazet@google.com>,
        Andrew Lunn <andrew@lunn.ch>, davem@davemloft.net,
        Woojung Huh <woojung.huh@microchip.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Florian Fainelli <f.fainelli@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, UNGLinuxDriver@microchip.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Vladimir Oltean <vladimir.oltean@nxp.com>,
        Lukasz Majewski <lukma@denx.de>,
        Florian Fainelli <florian.fainelli@broadcom.com>
Subject: [PATCH v6 net-next 2/5] net: dsa: notify drivers of MAC address changes on user ports
Date:   Fri, 22 Sep 2023 15:31:05 +0200
Message-Id: <20230922133108.2090612-3-lukma@denx.de>
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From: Vladimir Oltean <vladimir.oltean@nxp.com>

In some cases, drivers may need to veto the changing of a MAC address on
a user port. Such is the case with KSZ9477 when it offloads a HSR device,
because it programs the MAC address of multiple ports to a shared
hardware register. Those ports need to have equal MAC addresses for the
lifetime of the HSR offload.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
---
Changes for v5:
- New patch
Changes for v6:
- None
---
 include/net/dsa.h | 10 ++++++++++
 net/dsa/slave.c   |  7 +++++++
 2 files changed, 17 insertions(+)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 426724808e76..d98439ea6146 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -969,6 +969,16 @@ struct dsa_switch_ops {
 			       struct phy_device *phy);
 	void	(*port_disable)(struct dsa_switch *ds, int port);
 
+
+	/*
+	 * Notification for MAC address changes on user ports. Drivers can
+	 * currently only veto operations. They should not use the method to
+	 * program the hardware, since the operation is not rolled back in case
+	 * of other errors.
+	 */
+	int	(*port_set_mac_address)(struct dsa_switch *ds, int port,
+					const unsigned char *addr);
+
 	/*
 	 * Compatibility between device trees defining multiple CPU ports and
 	 * drivers which are not OK to use by default the numerically smallest
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 2b3d89b77121..4c3e502d7e16 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -457,6 +457,13 @@ static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
 	if (!is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;
 
+	if (ds->ops->port_set_mac_address) {
+		err = ds->ops->port_set_mac_address(ds, dp->index,
+						    addr->sa_data);
+		if (err)
+			return err;
+	}
+
 	/* If the port is down, the address isn't synced yet to hardware or
 	 * to the DSA master, so there is nothing to change.
 	 */
-- 
2.20.1