enetc: mark TX timestamp type per skb

Mark TX timestamp type per skb on skb->cb[0], instead of
global variable for all skbs. This is a preparation for
one step timestamp support.

For one-step timestamping enablement, there will be both
one-step and two-step PTP messages to transfer. And a skb
queue is needed for one-step PTP messages making sure
start to send current message only after the last one
completed on hardware. (ENETC single-step register has to
be dynamically configured per message.) So, marking TX
timestamp type per skb is required.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -67,8 +67,7 @@ static void enetc_update_tx_ring_tail(struct enetc_bdr *tx_ring)
 	enetc_wr_reg_hot(tx_ring->tpir, tx_ring->next_to_use);
 }
 
-static int enetc_map_tx_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb,
-			      int active_offloads)
+static int enetc_map_tx_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb)
 {
 	struct enetc_tx_swbd *tx_swbd;
 	skb_frag_t *frag;
@@ -101,7 +100,7 @@ static int enetc_map_tx_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb,
 	count++;
 
 	do_vlan = skb_vlan_tag_present(skb);
-	do_tstamp = (active_offloads & ENETC_F_TX_TSTAMP) &&
+	do_tstamp = (skb->cb[0] & ENETC_F_TX_TSTAMP) &&
 		    (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP);
 	tx_swbd->do_tstamp = do_tstamp;
 	tx_swbd->check_wb = tx_swbd->do_tstamp;
@@ -221,6 +220,9 @@ netdev_tx_t enetc_xmit(struct sk_buff *skb, struct net_device *ndev)
 	struct enetc_bdr *tx_ring;
 	int count;
 
+	/* cb[0] used for TX timestamp type */
+	skb->cb[0] = priv->active_offloads & ENETC_F_TX_TSTAMP_MASK;
+
 	tx_ring = priv->tx_ring[skb->queue_mapping];
 
 	if (unlikely(skb_shinfo(skb)->nr_frags > ENETC_MAX_SKB_FRAGS))
@@ -234,7 +236,7 @@ netdev_tx_t enetc_xmit(struct sk_buff *skb, struct net_device *ndev)
 	}
 
 	enetc_lock_mdio();
-	count = enetc_map_tx_buffs(tx_ring, skb, priv->active_offloads);
+	count = enetc_map_tx_buffs(tx_ring, skb);
 	enetc_unlock_mdio();
 
 	if (unlikely(!count))

drivers/net/ethernet/freescale/enetc/enetc.h

@@ -271,12 +271,15 @@ struct psfp_cap {
 	u32 max_psfp_meter;
 };
 
+#define ENETC_F_TX_TSTAMP_MASK	0xff
 /* TODO: more hardware offloads */
 enum enetc_active_offloads {
-	ENETC_F_RX_TSTAMP	= BIT(0),
-	ENETC_F_TX_TSTAMP	= BIT(1),
-	ENETC_F_QBV             = BIT(2),
-	ENETC_F_QCI		= BIT(3),
+	/* 8 bits reserved for TX timestamp types (hwtstamp_tx_types) */
+	ENETC_F_TX_TSTAMP	= BIT(0),
+
+	ENETC_F_RX_TSTAMP	= BIT(8),
+	ENETC_F_QBV		= BIT(9),
+	ENETC_F_QCI		= BIT(10),
 };
 
 /* interrupt coalescing modes */