drivers: net: xgene: Fix module unload crash - change sw sequence

When the driver is configured as kernel module and when it gets
unloaded and reloaded, kernel crash was observed.  This patch
addresses the software cleanup by doing the following,

- Moved register_netdev call after hardware is ready
- Since ndev is not ready, added set_irq_name to set irq name
- Since ndev is not ready, changed mdio_bus->parent to pdev->dev
- Replaced netif_start(stop)_queue by netif_tx_start(stop)_queues
- Removed napi_del call since it's called by free_netdev
- Added dev_close call, within remove
- Added shutdown callback
- Changed to use dmam_ APIs

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Tested-by: Fushen Chen <fchen@apm.com>
Tested-by: Toan Le <toanle@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/apm/xgene/xgene_enet_hw.c

@@ -901,7 +901,7 @@ int xgene_enet_mdio_config(struct xgene_enet_pdata *pdata)
 		 ndev->name);
 
 	mdio_bus->priv = pdata;
-	mdio_bus->parent = &ndev->dev;
+	mdio_bus->parent = &pdata->pdev->dev;
 
 	ret = xgene_mdiobus_register(pdata, mdio_bus);
 	if (ret) {

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

@@ -608,6 +608,30 @@ static void xgene_enet_timeout(struct net_device *ndev)
 	}
 }
 
+static void xgene_enet_set_irq_name(struct net_device *ndev)
+{
+	struct xgene_enet_pdata *pdata = netdev_priv(ndev);
+	struct xgene_enet_desc_ring *ring;
+	int i;
+
+	for (i = 0; i < pdata->rxq_cnt; i++) {
+		ring = pdata->rx_ring[i];
+		if (!pdata->cq_cnt) {
+			snprintf(ring->irq_name, IRQ_ID_SIZE, "%s-rx-txc",
+				 ndev->name);
+		} else {
+			snprintf(ring->irq_name, IRQ_ID_SIZE, "%s-rx-%d",
+				 ndev->name, i);
+		}
+	}
+
+	for (i = 0; i < pdata->cq_cnt; i++) {
+		ring = pdata->tx_ring[i]->cp_ring;
+		snprintf(ring->irq_name, IRQ_ID_SIZE, "%s-txc-%d",
+			 ndev->name, i);
+	}
+}
+
 static int xgene_enet_register_irq(struct net_device *ndev)
 {
 	struct xgene_enet_pdata *pdata = netdev_priv(ndev);
@@ -615,6 +639,7 @@ static int xgene_enet_register_irq(struct net_device *ndev)
 	struct xgene_enet_desc_ring *ring;
 	int ret = 0, i;
 
+	xgene_enet_set_irq_name(ndev);
 	for (i = 0; i < pdata->rxq_cnt; i++) {
 		ring = pdata->rx_ring[i];
 		irq_set_status_flags(ring->irq, IRQ_DISABLE_UNLAZY);
@@ -723,7 +748,7 @@ static int xgene_enet_open(struct net_device *ndev)
 
 	mac_ops->tx_enable(pdata);
 	mac_ops->rx_enable(pdata);
-	netif_start_queue(ndev);
+	netif_tx_start_all_queues(ndev);
 
 	return ret;
 }
@@ -734,7 +759,7 @@ static int xgene_enet_close(struct net_device *ndev)
 	const struct xgene_mac_ops *mac_ops = pdata->mac_ops;
 	int i;
 
-	netif_stop_queue(ndev);
+	netif_tx_stop_all_queues(ndev);
 	mac_ops->tx_disable(pdata);
 	mac_ops->rx_disable(pdata);
 
@@ -759,7 +784,7 @@ static void xgene_enet_delete_ring(struct xgene_enet_desc_ring *ring)
 	dev = ndev_to_dev(ring->ndev);
 
 	pdata->ring_ops->clear(ring);
-	dma_free_coherent(dev, ring->size, ring->desc_addr, ring->dma);
+	dmam_free_coherent(dev, ring->size, ring->desc_addr, ring->dma);
 }
 
 static void xgene_enet_delete_desc_rings(struct xgene_enet_pdata *pdata)
@@ -834,7 +859,7 @@ static void xgene_enet_free_desc_ring(struct xgene_enet_desc_ring *ring)
 
 	if (ring->desc_addr) {
 		pdata->ring_ops->clear(ring);
-		dma_free_coherent(dev, ring->size, ring->desc_addr, ring->dma);
+		dmam_free_coherent(dev, ring->size, ring->desc_addr, ring->dma);
 	}
 	devm_kfree(dev, ring);
 }
@@ -892,9 +917,10 @@ static struct xgene_enet_desc_ring *xgene_enet_create_desc_ring(
 			struct net_device *ndev, u32 ring_num,
 			enum xgene_enet_ring_cfgsize cfgsize, u32 ring_id)
 {
-	struct xgene_enet_desc_ring *ring;
 	struct xgene_enet_pdata *pdata = netdev_priv(ndev);
 	struct device *dev = ndev_to_dev(ndev);
+	struct xgene_enet_desc_ring *ring;
+	void *irq_mbox_addr;
 	int size;
 
 	size = xgene_enet_get_ring_size(dev, cfgsize);
@@ -911,8 +937,8 @@ static struct xgene_enet_desc_ring *xgene_enet_create_desc_ring(
 	ring->cfgsize = cfgsize;
 	ring->id = ring_id;
 
-	ring->desc_addr = dma_zalloc_coherent(dev, size, &ring->dma,
-					      GFP_KERNEL);
+	ring->desc_addr = dmam_alloc_coherent(dev, size, &ring->dma,
+					      GFP_KERNEL | __GFP_ZERO);
 	if (!ring->desc_addr) {
 		devm_kfree(dev, ring);
 		return NULL;
@@ -920,14 +946,16 @@ static struct xgene_enet_desc_ring *xgene_enet_create_desc_ring(
 	ring->size = size;
 
 	if (is_irq_mbox_required(pdata, ring)) {
-		ring->irq_mbox_addr = dma_zalloc_coherent(dev, INTR_MBOX_SIZE,
-				&ring->irq_mbox_dma, GFP_KERNEL);
-		if (!ring->irq_mbox_addr) {
-			dma_free_coherent(dev, size, ring->desc_addr,
-					  ring->dma);
+		irq_mbox_addr = dmam_alloc_coherent(dev, INTR_MBOX_SIZE,
+						    &ring->irq_mbox_dma,
+						    GFP_KERNEL | __GFP_ZERO);
+		if (!irq_mbox_addr) {
+			dmam_free_coherent(dev, size, ring->desc_addr,
+					   ring->dma);
 			devm_kfree(dev, ring);
 			return NULL;
 		}
+		ring->irq_mbox_addr = irq_mbox_addr;
 	}
 
 	ring->cmd_base = xgene_enet_ring_cmd_base(pdata, ring);
@@ -988,6 +1016,7 @@ static int xgene_enet_create_desc_rings(struct net_device *ndev)
 	u8 eth_bufnum = pdata->eth_bufnum;
 	u8 bp_bufnum = pdata->bp_bufnum;
 	u16 ring_num = pdata->ring_num;
+	__le64 *exp_bufs;
 	u16 ring_id;
 	int i, ret, size;
 
@@ -1019,13 +1048,6 @@ static int xgene_enet_create_desc_rings(struct net_device *ndev)
 		rx_ring->nbufpool = NUM_BUFPOOL;
 		rx_ring->buf_pool = buf_pool;
 		rx_ring->irq = pdata->irqs[i];
-		if (!pdata->cq_cnt) {
-			snprintf(rx_ring->irq_name, IRQ_ID_SIZE, "%s-rx-txc",
-				 ndev->name);
-		} else {
-			snprintf(rx_ring->irq_name, IRQ_ID_SIZE, "%s-rx%d",
-				 ndev->name, i);
-		}
 		buf_pool->rx_skb = devm_kcalloc(dev, buf_pool->slots,
 						sizeof(struct sk_buff *),
 						GFP_KERNEL);
@@ -1052,13 +1074,13 @@ static int xgene_enet_create_desc_rings(struct net_device *ndev)
 		}
 
 		size = (tx_ring->slots / 2) * sizeof(__le64) * MAX_EXP_BUFFS;
-		tx_ring->exp_bufs = dma_zalloc_coherent(dev, size,
-							&dma_exp_bufs,
-							GFP_KERNEL);
-		if (!tx_ring->exp_bufs) {
+		exp_bufs = dmam_alloc_coherent(dev, size, &dma_exp_bufs,
+					       GFP_KERNEL | __GFP_ZERO);
+		if (!exp_bufs) {
 			ret = -ENOMEM;
 			goto err;
 		}
+		tx_ring->exp_bufs = exp_bufs;
 
 		pdata->tx_ring[i] = tx_ring;
 
@@ -1078,8 +1100,6 @@ static int xgene_enet_create_desc_rings(struct net_device *ndev)
 
 			cp_ring->irq = pdata->irqs[pdata->rxq_cnt + i];
 			cp_ring->index = i;
-			snprintf(cp_ring->irq_name, IRQ_ID_SIZE, "%s-txc%d",
-				 ndev->name, i);
 		}
 
 		cp_ring->cp_skb = devm_kcalloc(dev, tx_ring->slots,
@@ -1549,22 +1569,6 @@ static void xgene_enet_napi_add(struct xgene_enet_pdata *pdata)
 	}
 }
 
-static void xgene_enet_napi_del(struct xgene_enet_pdata *pdata)
-{
-	struct napi_struct *napi;
-	int i;
-
-	for (i = 0; i < pdata->rxq_cnt; i++) {
-		napi = &pdata->rx_ring[i]->napi;
-		netif_napi_del(napi);
-	}
-
-	for (i = 0; i < pdata->cq_cnt; i++) {
-		napi = &pdata->tx_ring[i]->cp_ring->napi;
-		netif_napi_del(napi);
-	}
-}
-
 static int xgene_enet_probe(struct platform_device *pdev)
 {
 	struct net_device *ndev;
@@ -1628,12 +1632,6 @@ static int xgene_enet_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	ret = register_netdev(ndev);
-	if (ret) {
-		netdev_err(ndev, "Failed to register netdev\n");
-		goto err;
-	}
-
 	ret = xgene_enet_init_hw(pdata);
 	if (ret)
 		goto err_netdev;
@@ -1648,7 +1646,14 @@ static int xgene_enet_probe(struct platform_device *pdev)
 	}
 
 	xgene_enet_napi_add(pdata);
+	ret = register_netdev(ndev);
+	if (ret) {
+		netdev_err(ndev, "Failed to register netdev\n");
+		goto err;
+	}
+
 	return 0;
+
 err_netdev:
 	unregister_netdev(ndev);
 err:
@@ -1666,10 +1671,14 @@ static int xgene_enet_remove(struct platform_device *pdev)
 	mac_ops = pdata->mac_ops;
 	ndev = pdata->ndev;
 
+	rtnl_lock();
+	if (netif_running(ndev))
+		dev_close(ndev);
+	rtnl_unlock();
+
 	mac_ops->rx_disable(pdata);
 	mac_ops->tx_disable(pdata);
 
-	xgene_enet_napi_del(pdata);
 	if (pdata->phy_mode == PHY_INTERFACE_MODE_RGMII)
 		xgene_enet_mdio_remove(pdata);
 	unregister_netdev(ndev);
@@ -1680,6 +1689,20 @@ static int xgene_enet_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void xgene_enet_shutdown(struct platform_device *pdev)
+{
+	struct xgene_enet_pdata *pdata;
+
+	pdata = platform_get_drvdata(pdev);
+	if (!pdata)
+		return;
+
+	if (!pdata->ndev)
+		return;
+
+	xgene_enet_remove(pdev);
+}
+
 #ifdef CONFIG_ACPI
 static const struct acpi_device_id xgene_enet_acpi_match[] = {
 	{ "APMC0D05", XGENE_ENET1},
@@ -1714,6 +1737,7 @@ static struct platform_driver xgene_enet_driver = {
 	},
 	.probe = xgene_enet_probe,
 	.remove = xgene_enet_remove,
+	.shutdown = xgene_enet_shutdown,
 };
 
 module_platform_driver(xgene_enet_driver);