[PATCH 3/3] sh_eth: Fix dma mapping issue

[Yoshihiro Kaneko <ykaneko0929@gmail.com>]

From: Mitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>

When CONFIG_DMA_API_DEBUG=y, many DMA error messages reports.
In order to use DMA debug, This patch fix following issues.

Issue 1:
If dma_mapping_error function is not called appropriately after
DMA mapping, DMA debug will report error message when DMA unmap
function is called.

Issue 2:
If skb_reserve function is called after DMA mapping, the relationship
between mapping addr and mapping size will be broken.
In this case, DMA debug will report error messages when DMA sync
function and DMA unmap function are called.

Issue 3:
If the size of frame data is less than ETH_ZLEN, the size is resized
to ETH_ZLEN after DMA map function is called.
In the TX skb freeing function, dma unmap function is called with that
resized value. So, unmap size error will reported.

Issue 4:
In the rx function, DMA map function is called without DMA unmap function
is called for RX skb reallocating.
It will case the DMA debug error that number of debug entry is full and
DMA debug logic is stopped.

Signed-off-by: Mitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
---
 drivers/net/ethernet/renesas/sh_eth.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 0e4a407..23318cf 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1136,6 +1136,11 @@ static void sh_eth_ring_format(struct net_device *ndev)
 		dma_map_single(&ndev->dev, skb->data, rxdesc->buffer_length,
 			       DMA_FROM_DEVICE);
 		rxdesc->addr = virt_to_phys(skb->data);
+		if (dma_mapping_error(&ndev->dev, rxdesc->addr)) {
+			dev_kfree_skb(mdp->rx_skbuff[i]);
+			mdp->rx_skbuff[i] = NULL;
+			break;
+		}
 		rxdesc->status = cpu_to_edmac(mdp, RD_RACT | RD_RFP);
 
 		/* Rx descriptor address set */
@@ -1364,7 +1369,7 @@ static int sh_eth_txfree(struct net_device *ndev)
 		if (mdp->tx_skbuff[entry]) {
 			dma_unmap_single(&ndev->dev, txdesc->addr,
 					 txdesc->buffer_length, DMA_TO_DEVICE);
-			dev_kfree_skb_irq(mdp->tx_skbuff[entry]);
+			dev_kfree_skb_any(mdp->tx_skbuff[entry]);
 			mdp->tx_skbuff[entry] = NULL;
 			free_num++;
 		}
@@ -1466,11 +1471,19 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
 			if (skb = NULL)
 				break;	/* Better luck next round. */
 			sh_eth_set_receive_align(skb);
+			dma_unmap_single(&ndev->dev, rxdesc->addr,
+					 rxdesc->buffer_length,
+					 DMA_FROM_DEVICE);
 			dma_map_single(&ndev->dev, skb->data,
 				       rxdesc->buffer_length, DMA_FROM_DEVICE);
 
 			skb_checksum_none_assert(skb);
 			rxdesc->addr = virt_to_phys(skb->data);
+			if (dma_mapping_error(&ndev->dev, rxdesc->addr)) {
+				dev_kfree_skb_any(mdp->rx_skbuff[entry]);
+				mdp->rx_skbuff[entry] = NULL;
+				break;
+			}
 		}
 		if (entry >= mdp->num_rx_ring - 1)
 			rxdesc->status |@@ -2104,12 +2117,18 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	if (!mdp->cd->hw_swap)
 		sh_eth_soft_swap(phys_to_virt(ALIGN(txdesc->addr, 4)),
 				 skb->len + 2);
-	txdesc->addr = dma_map_single(&ndev->dev, skb->data, skb->len,
-				      DMA_TO_DEVICE);
 	if (skb->len < ETH_ZLEN)
 		txdesc->buffer_length = ETH_ZLEN;
 	else
 		txdesc->buffer_length = skb->len;
+	txdesc->addr = dma_map_single(&ndev->dev, skb->data,
+				      txdesc->buffer_length,
+				      DMA_TO_DEVICE);
+	if (dma_mapping_error(&ndev->dev, txdesc->addr)) {
+		dev_kfree_skb_any(mdp->tx_skbuff[entry]);
+		mdp->tx_skbuff[entry] = NULL;
+		goto out;
+	}
 
 	if (entry >= mdp->num_tx_ring - 1)
 		txdesc->status |= cpu_to_edmac(mdp, TD_TACT | TD_TDLE);
@@ -2121,6 +2140,7 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	if (!(sh_eth_read(ndev, EDTRR) & sh_eth_get_edtrr_trns(mdp)))
 		sh_eth_write(ndev, sh_eth_get_edtrr_trns(mdp), EDTRR);
 
+out:
 	return NETDEV_TX_OK;
 }
 
-- 
1.9.1