net: ethernet: ti: davinci_emac: Use platform_get_irq() to get the interrupt

platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.

In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq() for DT users only.

While at it propagate error code in case request_irq() fails instead of
returning -EBUSY.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/davinci_emac.c

@@ -1454,15 +1454,24 @@ static int emac_dev_open(struct net_device *ndev)
 	}
 
 	/* Request IRQ */
-	while ((res = platform_get_resource(priv->pdev, IORESOURCE_IRQ,
-					    res_num))) {
-		for (irq_num = res->start; irq_num <= res->end; irq_num++) {
-			if (request_irq(irq_num, emac_irq, 0, ndev->name,
-					ndev)) {
-				dev_err(emac_dev,
-					"DaVinci EMAC: request_irq() failed\n");
-				ret = -EBUSY;
+	if (dev_of_node(&priv->pdev->dev)) {
+		while ((ret = platform_get_irq_optional(priv->pdev, res_num)) != -ENXIO) {
+			if (ret < 0)
+				goto rollback;
 
+			ret = request_irq(ret, emac_irq, 0, ndev->name, ndev);
+			if (ret) {
+				dev_err(emac_dev, "DaVinci EMAC: request_irq() failed\n");
+				goto rollback;
+			}
+			res_num++;
+		}
+	} else {
+		while ((res = platform_get_resource(priv->pdev, IORESOURCE_IRQ, res_num))) {
+			for (irq_num = res->start; irq_num <= res->end; irq_num++) {
+				ret = request_irq(irq_num, emac_irq, 0, ndev->name, ndev);
+				if (ret) {
+					dev_err(emac_dev, "DaVinci EMAC: request_irq() failed\n");
 					goto rollback;
 				}
 			}
@@ -1471,6 +1480,7 @@ static int emac_dev_open(struct net_device *ndev)
 		/* prepare counters for rollback in case of an error */
 		res_num--;
 		irq_num--;
+	}
 
 	/* Start/Enable EMAC hardware */
 	emac_hw_enable(priv);
@@ -1554,6 +1564,13 @@ static int emac_dev_open(struct net_device *ndev)
 	napi_disable(&priv->napi);
 
 rollback:
+	if (dev_of_node(&priv->pdev->dev)) {
+		for (q = res_num - 1; q >= 0; q--) {
+			irq_num = platform_get_irq(priv->pdev, q);
+			if (irq_num > 0)
+				free_irq(irq_num, ndev);
+		}
+	} else {
 		for (q = res_num; q >= 0; q--) {
 			res = platform_get_resource(priv->pdev, IORESOURCE_IRQ, q);
 			/* at the first iteration, irq_num is already set to the
@@ -1565,6 +1582,7 @@ static int emac_dev_open(struct net_device *ndev)
 			for (m = irq_num; m >= res->start; m--)
 				free_irq(m, ndev);
 		}
+	}
 	cpdma_ctlr_stop(priv->dma);
 	pm_runtime_put(&priv->pdev->dev);
 	return ret;
@@ -1899,13 +1917,10 @@ static int davinci_emac_probe(struct platform_device *pdev)
 		goto err_free_txchan;
 	}
 
-	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "error getting irq res\n");
-		rc = -ENOENT;
+	rc = platform_get_irq(pdev, 0);
+	if (rc < 0)
 		goto err_free_rxchan;
-	}
-	ndev->irq = res->start;
+	ndev->irq = rc;
 
 	rc = davinci_emac_try_get_mac(pdev, res_ctrl ? 0 : 1, priv->mac_addr);
 	if (!rc)