bnxt_en: Add a set of TX rings to support XDP.

Add logic for an extra set of TX rings for XDP.  If enabled, this
set of TX rings equals the number of RX rings and shares the same
IRQ as the RX ring set.  A new field bp->tx_nr_rings_xdp is added
to keep track of these TX XDP rings.  Adjust all other relevant functions
to handle bp->tx_nr_rings_xdp.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -2218,6 +2218,8 @@ static int bnxt_alloc_tx_rings(struct bnxt *bp)
 			memset(txr->tx_push, 0, sizeof(struct tx_push_bd));
 		}
 		ring->queue_id = bp->q_info[j].queue_id;
+		if (i < bp->tx_nr_rings_xdp)
+			continue;
 		if (i % bp->tx_nr_rings_per_tc == (bp->tx_nr_rings_per_tc - 1))
 			j++;
 	}
@@ -3042,8 +3044,10 @@ static int bnxt_alloc_mem(struct bnxt *bp, bool irq_re_init)
 		for (i = 0; i < bp->tx_nr_rings; i++, j++) {
 			bp->tx_ring[i].bnapi = bp->bnapi[j];
 			bp->bnapi[j]->tx_ring = &bp->tx_ring[i];
-			bp->tx_ring_map[i] = i;
-			bp->tx_ring[i].txq_index = i;
+			bp->tx_ring_map[i] = bp->tx_nr_rings_xdp + i;
+			if (i >= bp->tx_nr_rings_xdp)
+				bp->tx_ring[i].txq_index = i -
+					bp->tx_nr_rings_xdp;
 		}
 
 		rc = bnxt_alloc_stats(bp);
@@ -4966,7 +4970,8 @@ static int bnxt_set_real_num_queues(struct bnxt *bp)
 	int rc;
 	struct net_device *dev = bp->dev;
 
-	rc = netif_set_real_num_tx_queues(dev, bp->tx_nr_rings);
+	rc = netif_set_real_num_tx_queues(dev, bp->tx_nr_rings -
+					  bp->tx_nr_rings_xdp);
 	if (rc)
 		return rc;
 
@@ -6582,7 +6587,7 @@ static void bnxt_sp_task(struct work_struct *work)
 }
 
 /* Under rtnl_lock */
-int bnxt_reserve_rings(struct bnxt *bp, int tx, int rx, int tcs)
+int bnxt_reserve_rings(struct bnxt *bp, int tx, int rx, int tcs, int tx_xdp)
 {
 	int max_rx, max_tx, tx_sets = 1;
 	int tx_rings_needed;
@@ -6602,12 +6607,12 @@ int bnxt_reserve_rings(struct bnxt *bp, int tx, int rx, int tcs)
 	if (max_rx < rx)
 		return -ENOMEM;
 
-	tx_rings_needed = tx * tx_sets;
+	tx_rings_needed = tx * tx_sets + tx_xdp;
 	if (max_tx < tx_rings_needed)
 		return -ENOMEM;
 
 	if (bnxt_hwrm_reserve_tx_rings(bp, &tx_rings_needed) ||
-	    tx_rings_needed < (tx * tx_sets))
+	    tx_rings_needed < (tx * tx_sets + tx_xdp))
 		return -ENOMEM;
 	return 0;
 }
@@ -6788,8 +6793,8 @@ int bnxt_setup_mq_tc(struct net_device *dev, u8 tc)
 	if (bp->flags & BNXT_FLAG_SHARED_RINGS)
 		sh = true;
 
-	rc = bnxt_reserve_rings(bp, bp->tx_nr_rings_per_tc,
-				bp->rx_nr_rings, tc);
+	rc = bnxt_reserve_rings(bp, bp->tx_nr_rings_per_tc, bp->rx_nr_rings,
+				tc, bp->tx_nr_rings_xdp);
 	if (rc)
 		return rc;
 

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -1026,6 +1026,7 @@ struct bnxt {
 	int			tx_nr_pages;
 	int			tx_nr_rings;
 	int			tx_nr_rings_per_tc;
+	int			tx_nr_rings_xdp;
 
 	int			tx_wake_thresh;
 	int			tx_push_thresh;
@@ -1203,7 +1204,7 @@ int bnxt_hwrm_set_link_setting(struct bnxt *, bool, bool);
 int bnxt_hwrm_fw_set_time(struct bnxt *);
 int bnxt_open_nic(struct bnxt *, bool, bool);
 int bnxt_close_nic(struct bnxt *, bool, bool);
-int bnxt_reserve_rings(struct bnxt *bp, int tx, int rx, int tcs);
+int bnxt_reserve_rings(struct bnxt *bp, int tx, int rx, int tcs, int tx_xdp);
 int bnxt_setup_mq_tc(struct net_device *dev, u8 tc);
 int bnxt_get_max_rings(struct bnxt *, int *, int *, bool);
 void bnxt_restore_pf_fw_resources(struct bnxt *bp);

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -389,6 +389,7 @@ static int bnxt_set_channels(struct net_device *dev,
 	struct bnxt *bp = netdev_priv(dev);
 	int req_tx_rings, req_rx_rings, tcs;
 	bool sh = false;
+	int tx_xdp = 0;
 	int rc = 0;
 
 	if (channel->other_count)
@@ -413,7 +414,14 @@ static int bnxt_set_channels(struct net_device *dev,
 
 	req_tx_rings = sh ? channel->combined_count : channel->tx_count;
 	req_rx_rings = sh ? channel->combined_count : channel->rx_count;
-	rc = bnxt_reserve_rings(bp, req_tx_rings, req_rx_rings, tcs);
+	if (bp->tx_nr_rings_xdp) {
+		if (!sh) {
+			netdev_err(dev, "Only combined mode supported when XDP is enabled.\n");
+			return -EINVAL;
+		}
+		tx_xdp = req_rx_rings;
+	}
+	rc = bnxt_reserve_rings(bp, req_tx_rings, req_rx_rings, tcs, tx_xdp);
 	if (rc) {
 		netdev_warn(dev, "Unable to allocate the requested rings\n");
 		return rc;
@@ -442,10 +450,10 @@ static int bnxt_set_channels(struct net_device *dev,
 		bp->rx_nr_rings = channel->rx_count;
 		bp->tx_nr_rings_per_tc = channel->tx_count;
 	}
-
-	bp->tx_nr_rings = bp->tx_nr_rings_per_tc;
+	bp->tx_nr_rings_xdp = tx_xdp;
+	bp->tx_nr_rings = bp->tx_nr_rings_per_tc + tx_xdp;
 	if (tcs > 1)
-		bp->tx_nr_rings = bp->tx_nr_rings_per_tc * tcs;
+		bp->tx_nr_rings = bp->tx_nr_rings_per_tc * tcs + tx_xdp;
 
 	bp->cp_nr_rings = sh ? max_t(int, bp->tx_nr_rings, bp->rx_nr_rings) :
 			       bp->tx_nr_rings + bp->rx_nr_rings;