net: stmmac: Handle different error codes from platform_get_irq_byname

The following patch moved device tree interrupt resolution into
platform_get_irq_byname:

  ad69674e of/irq: do irq resolution in platform_get_irq_byname()

As a result, the function no longer only return -ENXIO on error.
This breaks DT based probing of stmmac, as seen in test runs of
linux-next next-20140526 cubie2-sunxi_defconfig:

  http://lists.linaro.org/pipermail/kernel-build-reports/2014-May/003659.html

This patch makes the stmmac_platform probe function properly handle
error codes, such as returning for deferred probing, and other codes
returned by of_irq_get_by_name.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -1753,7 +1753,7 @@ static int stmmac_open(struct net_device *dev)
 	}
 
 	/* Request the IRQ lines */
-	if (priv->lpi_irq != -ENXIO) {
+	if (priv->lpi_irq > 0) {
 		ret = request_irq(priv->lpi_irq, stmmac_interrupt, IRQF_SHARED,
 				  dev->name, dev);
 		if (unlikely(ret < 0)) {
@@ -1813,7 +1813,7 @@ static int stmmac_release(struct net_device *dev)
 	free_irq(dev->irq, dev);
 	if (priv->wol_irq != dev->irq)
 		free_irq(priv->wol_irq, dev);
-	if (priv->lpi_irq != -ENXIO)
+	if (priv->lpi_irq > 0)
 		free_irq(priv->lpi_irq, dev);
 
 	/* Stop TX/RX DMA and clear the descriptors */

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c

@@ -237,10 +237,12 @@ static int stmmac_pltfr_probe(struct platform_device *pdev)
 
 	/* Get the MAC information */
 	priv->dev->irq = platform_get_irq_byname(pdev, "macirq");
-	if (priv->dev->irq == -ENXIO) {
-		pr_err("%s: ERROR: MAC IRQ configuration "
-		       "information not found\n", __func__);
-		return -ENXIO;
+	if (priv->dev->irq < 0) {
+		if (priv->dev->irq != -EPROBE_DEFER) {
+			netdev_err(priv->dev,
+				   "MAC IRQ configuration information not found\n");
+		}
+		return priv->dev->irq;
 	}
 
 	/*
@@ -252,10 +254,15 @@ static int stmmac_pltfr_probe(struct platform_device *pdev)
 	 * so the driver will continue to use the mac irq (ndev->irq)
 	 */
 	priv->wol_irq = platform_get_irq_byname(pdev, "eth_wake_irq");
-	if (priv->wol_irq == -ENXIO)
+	if (priv->wol_irq < 0) {
+		if (priv->wol_irq == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
 		priv->wol_irq = priv->dev->irq;
+	}
 
 	priv->lpi_irq = platform_get_irq_byname(pdev, "eth_lpi");
+	if (priv->lpi_irq == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	platform_set_drvdata(pdev, priv->dev);