net: ethernet: ti: am65-cpsw: retain PORT_VLAN_REG after suspend/resume

During suspend resume the context of PORT_VLAN_REG is lost so
save it during suspend and restore it during resume for
host port and slave ports.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/am65-cpsw-nuss.c

@@ -2877,14 +2877,17 @@ static int am65_cpsw_nuss_suspend(struct device *dev)
 	struct am65_cpsw_port *port;
 	struct net_device *ndev;
 	int i, ret;
+	struct am65_cpsw_host *host_p = am65_common_get_host(common);
 
+	host_p->vid_context = readl(host_p->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
 	for (i = 0; i < common->port_num; i++) {
 		port = &common->ports[i];
 		ndev = port->ndev;
 
 		if (!ndev)
 			continue;
 
+		port->vid_context = readl(port->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
 		netif_device_detach(ndev);
 		if (netif_running(ndev)) {
 			rtnl_lock();
@@ -2908,6 +2911,7 @@ static int am65_cpsw_nuss_resume(struct device *dev)
 	struct am65_cpsw_port *port;
 	struct net_device *ndev;
 	int i, ret;
+	struct am65_cpsw_host *host_p = am65_common_get_host(common);
 
 	am65_cpts_resume(common->cpts);
 
@@ -2929,8 +2933,11 @@ static int am65_cpsw_nuss_resume(struct device *dev)
 		}
 
 		netif_device_attach(ndev);
+		writel(port->vid_context, port->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
 	}
 
+	writel(host_p->vid_context, host_p->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
+
 	return 0;
 }
 #endif /* CONFIG_PM_SLEEP */

drivers/net/ethernet/ti/am65-cpsw-nuss.h

@@ -55,12 +55,16 @@ struct am65_cpsw_port {
 	bool				rx_ts_enabled;
 	struct am65_cpsw_qos		qos;
 	struct devlink_port		devlink_port;
+	/* Only for suspend resume context */
+	u32				vid_context;
 };
 
 struct am65_cpsw_host {
 	struct am65_cpsw_common		*common;
 	void __iomem			*port_base;
 	void __iomem			*stat_base;
+	/* Only for suspend resume context */
+	u32				vid_context;
 };
 
 struct am65_cpsw_tx_chn {