dpaa2-eth: Add software annotation types

We write different metadata information in the software annotation
area of Tx frames, depending on frame type. Make this more explicit
by introducing a type field and separate structures for single buffer
and scatter-gather frames.
Signed-off-by: NIoana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c

@@ -571,10 +571,11 @@ static int build_sg_fd(struct dpaa2_eth_priv *priv,
 	 * all of them on Tx Conf.
 	 */
 	swa = (struct dpaa2_eth_swa *)sgt_buf;
-	swa->skb = skb;
-	swa->scl = scl;
-	swa->num_sg = num_sg;
-	swa->sgt_size = sgt_buf_size;
+	swa->type = DPAA2_ETH_SWA_SG;
+	swa->sg.skb = skb;
+	swa->sg.scl = scl;
+	swa->sg.num_sg = num_sg;
+	swa->sg.sgt_size = sgt_buf_size;
 
 	/* Separately map the SGT buffer */
 	addr = dma_map_single(dev, sgt_buf, sgt_buf_size, DMA_BIDIRECTIONAL);
@@ -609,7 +610,7 @@ static int build_single_fd(struct dpaa2_eth_priv *priv,
 {
 	struct device *dev = priv->net_dev->dev.parent;
 	u8 *buffer_start, *aligned_start;
-	struct sk_buff **skbh;
+	struct dpaa2_eth_swa *swa;
 	dma_addr_t addr;
 
 	buffer_start = skb->data - dpaa2_eth_needed_headroom(priv, skb);
@@ -626,8 +627,9 @@ static int build_single_fd(struct dpaa2_eth_priv *priv,
 	 * (in the private data area) such that we can release it
 	 * on Tx confirm
 	 */
-	skbh = (struct sk_buff **)buffer_start;
-	*skbh = skb;
+	swa = (struct dpaa2_eth_swa *)buffer_start;
+	swa->type = DPAA2_ETH_SWA_SINGLE;
+	swa->single.skb = skb;
 
 	addr = dma_map_single(dev, buffer_start,
 			      skb_tail_pointer(skb) - buffer_start,
@@ -659,17 +661,17 @@ static void free_tx_fd(const struct dpaa2_eth_priv *priv,
 {
 	struct device *dev = priv->net_dev->dev.parent;
 	dma_addr_t fd_addr;
-	struct sk_buff **skbh, *skb;
+	struct sk_buff *skb;
 	unsigned char *buffer_start;
 	struct dpaa2_eth_swa *swa;
 	u8 fd_format = dpaa2_fd_get_format(fd);
 
 	fd_addr = dpaa2_fd_get_addr(fd);
-	skbh = dpaa2_iova_to_virt(priv->iommu_domain, fd_addr);
+	buffer_start = dpaa2_iova_to_virt(priv->iommu_domain, fd_addr);
+	swa = (struct dpaa2_eth_swa *)buffer_start;
 
 	if (fd_format == dpaa2_fd_single) {
-		skb = *skbh;
-		buffer_start = (unsigned char *)skbh;
+		skb = swa->single.skb;
 		/* Accessing the skb buffer is safe before dma unmap, because
 		 * we didn't map the actual skb shell.
 		 */
@@ -677,15 +679,15 @@ static void free_tx_fd(const struct dpaa2_eth_priv *priv,
 				 skb_tail_pointer(skb) - buffer_start,
 				 DMA_BIDIRECTIONAL);
 	} else if (fd_format == dpaa2_fd_sg) {
-		swa = (struct dpaa2_eth_swa *)skbh;
-		skb = swa->skb;
+		skb = swa->sg.skb;
 
 		/* Unmap the scatterlist */
-		dma_unmap_sg(dev, swa->scl, swa->num_sg, DMA_BIDIRECTIONAL);
-		kfree(swa->scl);
+		dma_unmap_sg(dev, swa->sg.scl, swa->sg.num_sg,
+			     DMA_BIDIRECTIONAL);
+		kfree(swa->sg.scl);
 
 		/* Unmap the SGT buffer */
-		dma_unmap_single(dev, fd_addr, swa->sgt_size,
+		dma_unmap_single(dev, fd_addr, swa->sg.sgt_size,
 				 DMA_BIDIRECTIONAL);
 	} else {
 		netdev_dbg(priv->net_dev, "Invalid FD format\n");
@@ -695,7 +697,7 @@ static void free_tx_fd(const struct dpaa2_eth_priv *priv,
 	/* Get the timestamp value */
 	if (priv->tx_tstamp && skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) {
 		struct skb_shared_hwtstamps shhwtstamps;
-		__le64 *ts = dpaa2_get_ts(skbh, true);
+		__le64 *ts = dpaa2_get_ts(buffer_start, true);
 		u64 ns;
 
 		memset(&shhwtstamps, 0, sizeof(shhwtstamps));
@@ -707,7 +709,7 @@ static void free_tx_fd(const struct dpaa2_eth_priv *priv,
 
 	/* Free SGT buffer allocated on tx */
 	if (fd_format != dpaa2_fd_single)
-		skb_free_frag(skbh);
+		skb_free_frag(buffer_start);
 
 	/* Move on with skb release */
 	napi_consume_skb(skb, in_napi);

drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h

@@ -89,12 +89,28 @@
  */
 #define DPAA2_ETH_SWA_SIZE		64
 
+/* We store different information in the software annotation area of a Tx frame
+ * based on what type of frame it is
+ */
+enum dpaa2_eth_swa_type {
+	DPAA2_ETH_SWA_SINGLE,
+	DPAA2_ETH_SWA_SG,
+};
+
 /* Must keep this struct smaller than DPAA2_ETH_SWA_SIZE */
 struct dpaa2_eth_swa {
-	struct sk_buff *skb;
-	struct scatterlist *scl;
-	int num_sg;
-	int sgt_size;
+	enum dpaa2_eth_swa_type type;
+	union {
+		struct {
+			struct sk_buff *skb;
+		} single;
+		struct {
+			struct sk_buff *skb;
+			struct scatterlist *scl;
+			int num_sg;
+			int sgt_size;
+		} sg;
+	};
 };
 
 /* Annotation valid bits in FD FRC */