nfp: prepare for more TX metadata prepend

Subsequent patches will add support for more TX metadata fields.
Prepare for this by handling an additional double word - firmware
handle as metadata type 7.

Signed-off-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -808,24 +808,47 @@ static void nfp_net_tx_xmit_more_flush(struct nfp_net_tx_ring *tx_ring)
 	tx_ring->wr_ptr_add = 0;
 }
 
-static int nfp_net_prep_port_id(struct sk_buff *skb)
+static int nfp_net_prep_tx_meta(struct sk_buff *skb, u64 tls_handle)
 {
 	struct metadata_dst *md_dst = skb_metadata_dst(skb);
 	unsigned char *data;
+	u32 meta_id = 0;
+	int md_bytes;
 
-	if (likely(!md_dst))
-		return 0;
-	if (unlikely(md_dst->type != METADATA_HW_PORT_MUX))
+	if (likely(!md_dst && !tls_handle))
 		return 0;
+	if (unlikely(md_dst && md_dst->type != METADATA_HW_PORT_MUX)) {
+		if (!tls_handle)
+			return 0;
+		md_dst = NULL;
+	}
 
-	if (unlikely(skb_cow_head(skb, 8)))
+	md_bytes = 4 + !!md_dst * 4 + !!tls_handle * 8;
+
+	if (unlikely(skb_cow_head(skb, md_bytes)))
 		return -ENOMEM;
 
-	data = skb_push(skb, 8);
-	put_unaligned_be32(NFP_NET_META_PORTID, data);
-	put_unaligned_be32(md_dst->u.port_info.port_id, data + 4);
+	meta_id = 0;
+	data = skb_push(skb, md_bytes) + md_bytes;
+	if (md_dst) {
+		data -= 4;
+		put_unaligned_be32(md_dst->u.port_info.port_id, data);
+		meta_id = NFP_NET_META_PORTID;
+	}
+	if (tls_handle) {
+		/* conn handle is opaque, we just use u64 to be able to quickly
+		 * compare it to zero
+		 */
+		data -= 8;
+		memcpy(data, &tls_handle, sizeof(tls_handle));
+		meta_id <<= NFP_NET_META_FIELD_SIZE;
+		meta_id |= NFP_NET_META_CONN_HANDLE;
+	}
+
+	data -= 4;
+	put_unaligned_be32(meta_id, data);
 
-	return 8;
+	return md_bytes;
 }
 
 /**
@@ -848,6 +871,7 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
 	struct nfp_net_dp *dp;
 	dma_addr_t dma_addr;
 	unsigned int fsize;
+	u64 tls_handle = 0;
 	u16 qidx;
 
 	dp = &nn->dp;
@@ -869,7 +893,7 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
 		return NETDEV_TX_BUSY;
 	}
 
-	md_bytes = nfp_net_prep_port_id(skb);
+	md_bytes = nfp_net_prep_tx_meta(skb, tls_handle);
 	if (unlikely(md_bytes < 0))
 		goto err_flush;
 

drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h

@@ -44,6 +44,7 @@
 #define NFP_NET_META_MARK		2
 #define NFP_NET_META_PORTID		5
 #define NFP_NET_META_CSUM		6 /* checksum complete type */
+#define NFP_NET_META_CONN_HANDLE	7
 
 #define NFP_META_PORT_ID_CTRL		~0U