net: axienet: Support shared interrupts

Specify IRQF_SHARED to support shared interrupts. If the interrupt
handler is called and the device is not indicating an interrupt,
just return IRQ_NONE rather than spewing error messages.
Signed-off-by: Robert Hancock <hancock@sedsystems.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -809,7 +809,7 @@ static void axienet_recv(struct net_device *ndev)
  * @irq:	irq number
  * @_ndev:	net_device pointer
  *
- * Return: IRQ_HANDLED for all cases.
+ * Return: IRQ_HANDLED if device generated a TX interrupt, IRQ_NONE otherwise.
  *
  * This is the Axi DMA Tx done Isr. It invokes "axienet_start_xmit_done"
  * to complete the BD processing.
@@ -828,7 +828,7 @@ static irqreturn_t axienet_tx_irq(int irq, void *_ndev)
 		goto out;
 	}
 	if (!(status & XAXIDMA_IRQ_ALL_MASK))
-		dev_err(&ndev->dev, "No interrupts asserted in Tx path\n");
+		return IRQ_NONE;
 	if (status & XAXIDMA_IRQ_ERROR_MASK) {
 		dev_err(&ndev->dev, "DMA Tx error 0x%x\n", status);
 		dev_err(&ndev->dev, "Current BD is at: 0x%x\n",
@@ -858,7 +858,7 @@ static irqreturn_t axienet_tx_irq(int irq, void *_ndev)
  * @irq:	irq number
  * @_ndev:	net_device pointer
  *
- * Return: IRQ_HANDLED for all cases.
+ * Return: IRQ_HANDLED if device generated a RX interrupt, IRQ_NONE otherwise.
  *
  * This is the Axi DMA Rx Isr. It invokes "axienet_recv" to complete the BD
  * processing.
@@ -877,7 +877,7 @@ static irqreturn_t axienet_rx_irq(int irq, void *_ndev)
 		goto out;
 	}
 	if (!(status & XAXIDMA_IRQ_ALL_MASK))
-		dev_err(&ndev->dev, "No interrupts asserted in Rx path\n");
+		return IRQ_NONE;
 	if (status & XAXIDMA_IRQ_ERROR_MASK) {
 		dev_err(&ndev->dev, "DMA Rx error 0x%x\n", status);
 		dev_err(&ndev->dev, "Current BD is at: 0x%x\n",
@@ -953,11 +953,13 @@ static int axienet_open(struct net_device *ndev)
 		     (unsigned long) lp);
 
 	/* Enable interrupts for Axi DMA Tx */
-	ret = request_irq(lp->tx_irq, axienet_tx_irq, 0, ndev->name, ndev);
+	ret = request_irq(lp->tx_irq, axienet_tx_irq, IRQF_SHARED,
+			  ndev->name, ndev);
 	if (ret)
 		goto err_tx_irq;
 	/* Enable interrupts for Axi DMA Rx */
-	ret = request_irq(lp->rx_irq, axienet_rx_irq, 0, ndev->name, ndev);
+	ret = request_irq(lp->rx_irq, axienet_rx_irq, IRQF_SHARED,
+			  ndev->name, ndev);
 	if (ret)
 		goto err_rx_irq;