bnxt: add pause frame stats

These stats are already reported in ethtool -S.
Michael confirms they are equivalent to standard stats.

v2: - fix sparse warning about endian by using the macro
    - use u64 for pointer type
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1778,6 +1778,22 @@ static void bnxt_get_pauseparam(struct net_device *dev,
 	epause->tx_pause = !!(link_info->req_flow_ctrl & BNXT_LINK_PAUSE_TX);
 }
 
+static void bnxt_get_pause_stats(struct net_device *dev,
+				 struct ethtool_pause_stats *epstat)
+{
+	struct bnxt *bp = netdev_priv(dev);
+	u64 *rx, *tx;
+
+	if (BNXT_VF(bp) || !(bp->flags & BNXT_FLAG_PORT_STATS))
+		return;
+
+	rx = bp->port_stats.sw_stats;
+	tx = bp->port_stats.sw_stats + BNXT_TX_PORT_STATS_BYTE_OFFSET / 8;
+
+	epstat->rx_pause_frames = BNXT_GET_RX_PORT_STATS64(rx, rx_pause_frames);
+	epstat->tx_pause_frames = BNXT_GET_TX_PORT_STATS64(tx, tx_pause_frames);
+}
+
 static int bnxt_set_pauseparam(struct net_device *dev,
 			       struct ethtool_pauseparam *epause)
 {
@@ -3645,6 +3661,7 @@ const struct ethtool_ops bnxt_ethtool_ops = {
 				     ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
 	.get_link_ksettings	= bnxt_get_link_ksettings,
 	.set_link_ksettings	= bnxt_set_link_ksettings,
+	.get_pause_stats	= bnxt_get_pause_stats,
 	.get_pauseparam		= bnxt_get_pauseparam,
 	.set_pauseparam		= bnxt_set_pauseparam,
 	.get_drvinfo		= bnxt_get_drvinfo,