net: ethernet: ti: am65-cpsw: avoid devm_alloc_etherdev, fix module removal

Usage of devm_alloc_etherdev_mqs() conflicts with
am65_cpsw_nuss_cleanup_ndev() as the same struct net_device instances
get unregistered twice. Switch to alloc_etherdev_mqs() and make sure
am65_cpsw_nuss_cleanup_ndev() unregisters and frees those net_device
instances properly.

With this, it is finally possible to rmmod the driver without oopsing
the kernel.

Fixes: 93a76530 ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Reviewed-by: Roger Quadros <roger@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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

@@ -2744,10 +2744,9 @@ am65_cpsw_nuss_init_port_ndev(struct am65_cpsw_common *common, u32 port_idx)
 		return 0;
 
 	/* alloc netdev */
-	port->ndev = devm_alloc_etherdev_mqs(common->dev,
-					     sizeof(struct am65_cpsw_ndev_priv),
-					     AM65_CPSW_MAX_QUEUES,
-					     AM65_CPSW_MAX_QUEUES);
+	port->ndev = alloc_etherdev_mqs(sizeof(struct am65_cpsw_ndev_priv),
+					AM65_CPSW_MAX_QUEUES,
+					AM65_CPSW_MAX_QUEUES);
 	if (!port->ndev) {
 		dev_err(dev, "error allocating slave net_device %u\n",
 			port->port_id);
@@ -2868,8 +2867,12 @@ static void am65_cpsw_nuss_cleanup_ndev(struct am65_cpsw_common *common)
 
 	for (i = 0; i < common->port_num; i++) {
 		port = &common->ports[i];
-		if (port->ndev && port->ndev->reg_state == NETREG_REGISTERED)
+		if (!port->ndev)
+			continue;
+		if (port->ndev->reg_state == NETREG_REGISTERED)
 			unregister_netdev(port->ndev);
+		free_netdev(port->ndev);
+		port->ndev = NULL;
 	}
 }
 
@@ -3613,16 +3616,17 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
 
 	ret = am65_cpsw_nuss_init_ndevs(common);
 	if (ret)
-		goto err_free_phylink;
+		goto err_ndevs_clear;
 
 	ret = am65_cpsw_nuss_register_ndevs(common);
 	if (ret)
-		goto err_free_phylink;
+		goto err_ndevs_clear;
 
 	pm_runtime_put(dev);
 	return 0;
 
-err_free_phylink:
+err_ndevs_clear:
+	am65_cpsw_nuss_cleanup_ndev(common);
 	am65_cpsw_nuss_phylink_cleanup(common);
 	am65_cpts_release(common->cpts);
 err_of_clear: