[PATCH 05/12] net: ll_temac: Fix support for little-endian platforms

[Esben Haabendal]

Both TEMAC and SDMA is big-endian, so make sure that all values in SDMA
buffer descriptors (cmdac_bd) are handled as big-endian, independent of the
host endianness. With all currently supported platforms being big-endian,
this change does not make a change for any of them.

Note, when using app3 and app4 for piggybacking skb pointers there is no
need to care about endianness, as neither TEMAC nor SDMA access app3 and
app4 in TX buffer descriptors.

Signed-off-by: Esben Haabendal <esben@xxxxxxxxxx>
---
 drivers/net/ethernet/xilinx/ll_temac_main.c | 90 ++++++++++++++++-------------
 1 file changed, 51 insertions(+), 39 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 9c1fb9b..817bc57 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -258,6 +258,7 @@ static int temac_dma_bd_init(struct net_device *ndev)
 {
 	struct temac_local *lp = netdev_priv(ndev);
 	struct sk_buff *skb;
+	dma_addr_t skb_dma_addr;
 	int i;
 
 	lp->rx_skb = devm_kcalloc(&ndev->dev, RX_BD_NUM, sizeof(*lp->rx_skb),
@@ -280,13 +281,15 @@ static int temac_dma_bd_init(struct net_device *ndev)
 		goto out;
 
 	for (i = 0; i < TX_BD_NUM; i++) {
-		lp->tx_bd_v[i].next = lp->tx_bd_p +
-				sizeof(*lp->tx_bd_v) * ((i + 1) % TX_BD_NUM);
+		lp->tx_bd_v[i].next = cpu_to_be32(
+			lp->tx_bd_p
+			+ sizeof(*lp->tx_bd_v) * ((i + 1) % TX_BD_NUM));
 	}
 
 	for (i = 0; i < RX_BD_NUM; i++) {
-		lp->rx_bd_v[i].next = lp->rx_bd_p +
-				sizeof(*lp->rx_bd_v) * ((i + 1) % RX_BD_NUM);
+		lp->rx_bd_v[i].next = cpu_to_be32(
+			lp->rx_bd_p
+			+ sizeof(*lp->rx_bd_v) * ((i + 1) % RX_BD_NUM));
 
 		skb = netdev_alloc_skb_ip_align(ndev,
 						XTE_MAX_JUMBO_FRAME_SIZE);
@@ -295,12 +298,12 @@ static int temac_dma_bd_init(struct net_device *ndev)
 
 		lp->rx_skb[i] = skb;
 		/* returns physical address of skb->data */
-		lp->rx_bd_v[i].phys = dma_map_single(ndev->dev.parent,
-						     skb->data,
-						     XTE_MAX_JUMBO_FRAME_SIZE,
-						     DMA_FROM_DEVICE);
-		lp->rx_bd_v[i].len = XTE_MAX_JUMBO_FRAME_SIZE;
-		lp->rx_bd_v[i].app0 = STS_CTRL_APP0_IRQONEND;
+		skb_dma_addr = dma_map_single(ndev->dev.parent, skb->data,
+					      XTE_MAX_JUMBO_FRAME_SIZE,
+					      DMA_FROM_DEVICE);
+		lp->rx_bd_v[i].phys = cpu_to_be32(skb_dma_addr);
+		lp->rx_bd_v[i].len = cpu_to_be32(XTE_MAX_JUMBO_FRAME_SIZE);
+		lp->rx_bd_v[i].app0 = cpu_to_be32(STS_CTRL_APP0_IRQONEND);
 	}
 
 	lp->dma_out(lp, TX_CHNL_CTRL, 0x10220400 |
@@ -676,11 +679,11 @@ static void temac_start_xmit_done(struct net_device *ndev)
 	struct sk_buff *skb;
 
 	cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
-	stat = cur_p->app0;
+	stat = be32_to_cpu(cur_p->app0);
 
 	while (stat & STS_CTRL_APP0_CMPLT) {
-		dma_unmap_single(ndev->dev.parent, cur_p->phys, cur_p->len,
-				 DMA_TO_DEVICE);
+		dma_unmap_single(ndev->dev.parent, be32_to_cpu(cur_p->phys),
+				 be32_to_cpu(cur_p->len), DMA_TO_DEVICE);
 		skb = (struct sk_buff *)ptr_from_txbd(cur_p);
 		if (skb)
 			dev_consume_skb_irq(skb);
@@ -691,14 +694,14 @@ static void temac_start_xmit_done(struct net_device *ndev)
 		cur_p->app4 = 0;
 
 		ndev->stats.tx_packets++;
-		ndev->stats.tx_bytes += cur_p->len;
+		ndev->stats.tx_bytes += be32_to_cpu(cur_p->len);
 
 		lp->tx_bd_ci++;
 		if (lp->tx_bd_ci >= TX_BD_NUM)
 			lp->tx_bd_ci = 0;
 
 		cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
-		stat = cur_p->app0;
+		stat = be32_to_cpu(cur_p->app0);
 	}
 
 	netif_wake_queue(ndev);
@@ -732,7 +735,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
 	struct temac_local *lp = netdev_priv(ndev);
 	struct cdmac_bd *cur_p;
-	dma_addr_t start_p, tail_p;
+	dma_addr_t start_p, tail_p, skb_dma_addr;
 	int ii;
 	unsigned long num_frag;
 	skb_frag_t *frag;
@@ -753,15 +756,17 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 		unsigned int csum_start_off = skb_checksum_start_offset(skb);
 		unsigned int csum_index_off = csum_start_off + skb->csum_offset;
 
-		cur_p->app0 |= 1; /* TX Checksum Enabled */
-		cur_p->app1 = (csum_start_off << 16) | csum_index_off;
+		cur_p->app0 |= cpu_to_be32(0x000001); /* TX Checksum Enabled */
+		cur_p->app1 = cpu_to_be32((csum_start_off << 16)
+					  | csum_index_off);
 		cur_p->app2 = 0;  /* initial checksum seed */
 	}
 
-	cur_p->app0 |= STS_CTRL_APP0_SOP;
-	cur_p->len = skb_headlen(skb);
-	cur_p->phys = dma_map_single(ndev->dev.parent, skb->data,
-				     skb_headlen(skb), DMA_TO_DEVICE);
+	cur_p->app0 |= cpu_to_be32(STS_CTRL_APP0_SOP);
+	skb_dma_addr = dma_map_single(ndev->dev.parent, skb->data,
+				      skb_headlen(skb), DMA_TO_DEVICE);
+	cur_p->len = cpu_to_be32(skb_headlen(skb));
+	cur_p->phys = cpu_to_be32(skb_dma_addr);
 	ptr_to_txbd((void *)skb, cur_p);
 
 	for (ii = 0; ii < num_frag; ii++) {
@@ -770,14 +775,15 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 			lp->tx_bd_tail = 0;
 
 		cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
-		cur_p->phys = dma_map_single(ndev->dev.parent,
-					     skb_frag_address(frag),
-					     skb_frag_size(frag), DMA_TO_DEVICE);
-		cur_p->len = skb_frag_size(frag);
+		skb_dma_addr = dma_map_single(
+			ndev->dev.parent, skb_frag_address(frag),
+			skb_frag_size(frag), DMA_TO_DEVICE);
+		cur_p->phys = cpu_to_be32(skb_dma_addr);
+		cur_p->len = cpu_to_be32(skb_frag_size(frag));
 		cur_p->app0 = 0;
 		frag++;
 	}
-	cur_p->app0 |= STS_CTRL_APP0_EOP;
+	cur_p->app0 |= cpu_to_be32(STS_CTRL_APP0_EOP);
 
 	tail_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
 	lp->tx_bd_tail++;
@@ -799,7 +805,7 @@ static void ll_temac_recv(struct net_device *ndev)
 	struct sk_buff *skb, *new_skb;
 	unsigned int bdstat;
 	struct cdmac_bd *cur_p;
-	dma_addr_t tail_p;
+	dma_addr_t tail_p, skb_dma_addr;
 	int length;
 	unsigned long flags;
 
@@ -808,14 +814,14 @@ static void ll_temac_recv(struct net_device *ndev)
 	tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci;
 	cur_p = &lp->rx_bd_v[lp->rx_bd_ci];
 
-	bdstat = cur_p->app0;
+	bdstat = be32_to_cpu(cur_p->app0);
 	while ((bdstat & STS_CTRL_APP0_CMPLT)) {
 
 		skb = lp->rx_skb[lp->rx_bd_ci];
-		length = cur_p->app4 & 0x3FFF;
+		length = be32_to_cpu(cur_p->app4) & 0x3FFF;
 
-		dma_unmap_single(ndev->dev.parent, cur_p->phys, length,
-				 DMA_FROM_DEVICE);
+		dma_unmap_single(ndev->dev.parent, be32_to_cpu(cur_p->phys),
+				 length, DMA_FROM_DEVICE);
 
 		skb_put(skb, length);
 		skb->protocol = eth_type_trans(skb, ndev);
@@ -826,7 +832,12 @@ static void ll_temac_recv(struct net_device *ndev)
 		    (skb->protocol == htons(ETH_P_IP)) &&
 		    (skb->len > 64)) {
 
-			skb->csum = cur_p->app3 & 0xFFFF;
+			/* Convert from device endianness (be32) to cpu
+			 * endiannes, and if necessary swap the bytes
+			 * (back) for proper IP checksum byte order
+			 * (be16).
+			 */
+			skb->csum = htons(be32_to_cpu(cur_p->app3) & 0xFFFF);
 			skb->ip_summed = CHECKSUM_COMPLETE;
 		}
 
@@ -843,11 +854,12 @@ static void ll_temac_recv(struct net_device *ndev)
 			return;
 		}
 
-		cur_p->app0 = STS_CTRL_APP0_IRQONEND;
-		cur_p->phys = dma_map_single(ndev->dev.parent, new_skb->data,
-					     XTE_MAX_JUMBO_FRAME_SIZE,
-					     DMA_FROM_DEVICE);
-		cur_p->len = XTE_MAX_JUMBO_FRAME_SIZE;
+		cur_p->app0 = cpu_to_be32(STS_CTRL_APP0_IRQONEND);
+		skb_dma_addr = dma_map_single(ndev->dev.parent, new_skb->data,
+					      XTE_MAX_JUMBO_FRAME_SIZE,
+					      DMA_FROM_DEVICE);
+		cur_p->phys = cpu_to_be32(skb_dma_addr);
+		cur_p->len = cpu_to_be32(XTE_MAX_JUMBO_FRAME_SIZE);
 		lp->rx_skb[lp->rx_bd_ci] = new_skb;
 
 		lp->rx_bd_ci++;
@@ -855,7 +867,7 @@ static void ll_temac_recv(struct net_device *ndev)
 			lp->rx_bd_ci = 0;
 
 		cur_p = &lp->rx_bd_v[lp->rx_bd_ci];
-		bdstat = cur_p->app0;
+		bdstat = be32_to_cpu(cur_p->app0);
 	}
 	lp->dma_out(lp, RX_TAILDESC_PTR, tail_p);
 
-- 
2.4.11