net: macb: free resources on failure path of at91ether_open()

DMA buffers were not freed on failure path of at91ether_open().
Along with changes for freeing the DMA buffers the enable/disable
interrupt instructions were moved to at91ether_start()/at91ether_stop()
functions and the operations on at91ether_stop() were done in
their reverse order (compared with how is done in at91ether_start()):
before this patch the operation order on interface open path
was as follows:
1/ alloc DMA buffers
2/ enable tx, rx
3/ enable interrupts
and the order on interface close path was as follows:
1/ disable tx, rx
2/ disable interrupts
3/ free dma buffers.

Fixes: 7897b071 ("net: macb: convert to phylink")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb_main.c

@@ -3762,15 +3762,9 @@ static int macb_init(struct platform_device *pdev)
 
 static struct sifive_fu540_macb_mgmt *mgmt;
 
-/* Initialize and start the Receiver and Transmit subsystems */
-static int at91ether_start(struct net_device *dev)
+static int at91ether_alloc_coherent(struct macb *lp)
 {
-	struct macb *lp = netdev_priv(dev);
 	struct macb_queue *q = &lp->queues[0];
-	struct macb_dma_desc *desc;
-	dma_addr_t addr;
-	u32 ctl;
-	int i;
 
 	q->rx_ring = dma_alloc_coherent(&lp->pdev->dev,
 					 (AT91ETHER_MAX_RX_DESCR *
@@ -3792,6 +3786,43 @@ static int at91ether_start(struct net_device *dev)
 		return -ENOMEM;
 	}
 
+	return 0;
+}
+
+static void at91ether_free_coherent(struct macb *lp)
+{
+	struct macb_queue *q = &lp->queues[0];
+
+	if (q->rx_ring) {
+		dma_free_coherent(&lp->pdev->dev,
+				  AT91ETHER_MAX_RX_DESCR *
+				  macb_dma_desc_get_size(lp),
+				  q->rx_ring, q->rx_ring_dma);
+		q->rx_ring = NULL;
+	}
+
+	if (q->rx_buffers) {
+		dma_free_coherent(&lp->pdev->dev,
+				  AT91ETHER_MAX_RX_DESCR *
+				  AT91ETHER_MAX_RBUFF_SZ,
+				  q->rx_buffers, q->rx_buffers_dma);
+		q->rx_buffers = NULL;
+	}
+}
+
+/* Initialize and start the Receiver and Transmit subsystems */
+static int at91ether_start(struct macb *lp)
+{
+	struct macb_queue *q = &lp->queues[0];
+	struct macb_dma_desc *desc;
+	dma_addr_t addr;
+	u32 ctl;
+	int i, ret;
+
+	ret = at91ether_alloc_coherent(lp);
+	if (ret)
+		return ret;
+
 	addr = q->rx_buffers_dma;
 	for (i = 0; i < AT91ETHER_MAX_RX_DESCR; i++) {
 		desc = macb_rx_desc(q, i);
@@ -3813,9 +3844,39 @@ static int at91ether_start(struct net_device *dev)
 	ctl = macb_readl(lp, NCR);
 	macb_writel(lp, NCR, ctl | MACB_BIT(RE) | MACB_BIT(TE));
 
+	/* Enable MAC interrupts */
+	macb_writel(lp, IER, MACB_BIT(RCOMP)	|
+			     MACB_BIT(RXUBR)	|
+			     MACB_BIT(ISR_TUND)	|
+			     MACB_BIT(ISR_RLE)	|
+			     MACB_BIT(TCOMP)	|
+			     MACB_BIT(ISR_ROVR)	|
+			     MACB_BIT(HRESP));
+
 	return 0;
 }
 
+static void at91ether_stop(struct macb *lp)
+{
+	u32 ctl;
+
+	/* Disable MAC interrupts */
+	macb_writel(lp, IDR, MACB_BIT(RCOMP)	|
+			     MACB_BIT(RXUBR)	|
+			     MACB_BIT(ISR_TUND)	|
+			     MACB_BIT(ISR_RLE)	|
+			     MACB_BIT(TCOMP)	|
+			     MACB_BIT(ISR_ROVR) |
+			     MACB_BIT(HRESP));
+
+	/* Disable Receiver and Transmitter */
+	ctl = macb_readl(lp, NCR);
+	macb_writel(lp, NCR, ctl & ~(MACB_BIT(TE) | MACB_BIT(RE)));
+
+	/* Free resources. */
+	at91ether_free_coherent(lp);
+}
+
 /* Open the ethernet interface */
 static int at91ether_open(struct net_device *dev)
 {
@@ -3835,27 +3896,20 @@ static int at91ether_open(struct net_device *dev)
 
 	macb_set_hwaddr(lp);
 
-	ret = at91ether_start(dev);
+	ret = at91ether_start(lp);
 	if (ret)
 		goto pm_exit;
 
-	/* Enable MAC interrupts */
-	macb_writel(lp, IER, MACB_BIT(RCOMP)	|
-			     MACB_BIT(RXUBR)	|
-			     MACB_BIT(ISR_TUND)	|
-			     MACB_BIT(ISR_RLE)	|
-			     MACB_BIT(TCOMP)	|
-			     MACB_BIT(ISR_ROVR)	|
-			     MACB_BIT(HRESP));
-
 	ret = macb_phylink_connect(lp);
 	if (ret)
-		goto pm_exit;
+		goto stop;
 
 	netif_start_queue(dev);
 
 	return 0;
 
+stop:
+	at91ether_stop(lp);
 pm_exit:
 	pm_runtime_put_sync(&lp->pdev->dev);
 	return ret;
@@ -3865,37 +3919,13 @@ static int at91ether_open(struct net_device *dev)
 static int at91ether_close(struct net_device *dev)
 {
 	struct macb *lp = netdev_priv(dev);
-	struct macb_queue *q = &lp->queues[0];
-	u32 ctl;
-
-	/* Disable Receiver and Transmitter */
-	ctl = macb_readl(lp, NCR);
-	macb_writel(lp, NCR, ctl & ~(MACB_BIT(TE) | MACB_BIT(RE)));
-
-	/* Disable MAC interrupts */
-	macb_writel(lp, IDR, MACB_BIT(RCOMP)	|
-			     MACB_BIT(RXUBR)	|
-			     MACB_BIT(ISR_TUND)	|
-			     MACB_BIT(ISR_RLE)	|
-			     MACB_BIT(TCOMP)	|
-			     MACB_BIT(ISR_ROVR) |
-			     MACB_BIT(HRESP));
 
 	netif_stop_queue(dev);
 
 	phylink_stop(lp->phylink);
 	phylink_disconnect_phy(lp->phylink);
 
-	dma_free_coherent(&lp->pdev->dev,
-			  AT91ETHER_MAX_RX_DESCR *
-			  macb_dma_desc_get_size(lp),
-			  q->rx_ring, q->rx_ring_dma);
-	q->rx_ring = NULL;
-
-	dma_free_coherent(&lp->pdev->dev,
-			  AT91ETHER_MAX_RX_DESCR * AT91ETHER_MAX_RBUFF_SZ,
-			  q->rx_buffers, q->rx_buffers_dma);
-	q->rx_buffers = NULL;
+	at91ether_stop(lp);
 
 	return pm_runtime_put(&lp->pdev->dev);
 }