[PATCH 124/222] net:fec: add ethtool support for tx/rx ring sizes

[Russell King]

Add ethtool support to retrieve and set the transmit and receive ring
sizes.  This allows runtime tuning of these parameters, which can
result in better throughput with gigabit parts.

Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
 drivers/net/ethernet/freescale/fec_main.c | 47 +++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 11176d483db4..12d48b997744 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1631,6 +1631,51 @@ static int fec_enet_get_ts_info(struct net_device *ndev,
 	}
 }
 
+static void fec_enet_get_ringparam(struct net_device *ndev,
+				   struct ethtool_ringparam *ring)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+
+	ring->rx_max_pending = RX_RING_SIZE;
+	ring->tx_max_pending = TX_RING_SIZE;
+	ring->rx_pending = fep->rx_ring_size;
+	ring->tx_pending = fep->tx_ring_size;
+}
+
+static int fec_enet_set_ringparam(struct net_device *ndev,
+				   struct ethtool_ringparam *ring)
+{
+	struct fec_enet_private *fep = netdev_priv(ndev);
+	unsigned rx, tx, tx_min;
+
+	tx_min = ndev->features & NETIF_F_SG ? TX_RING_SIZE_MIN_SG : 16;
+
+	rx = clamp_t(u32, ring->rx_pending, 16, RX_RING_SIZE);
+	tx = clamp_t(u32, ring->tx_pending, tx_min, TX_RING_SIZE);
+
+	if (tx == fep->tx_ring_size && rx == fep->rx_ring_size)
+		return 0;
+
+	/* Setting the ring size while the interface is down is easy */
+	if (!netif_running(ndev)) {
+		fep->tx_ring_size = tx;
+		fep->rx_ring_size = rx;
+	} else {
+		return -EINVAL;
+
+		napi_disable(&fep->napi);
+		netif_tx_lock_bh(ndev);
+		fec_stop(ndev);
+		/* reallocate ring */
+		fec_restart(ndev);
+		netif_wake_queue(ndev);
+		netif_tx_unlock_bh(ndev);
+		napi_enable(&fep->napi);
+	}
+
+	return 0;
+}
+
 #if !defined(CONFIG_M5272)
 
 static void fec_enet_get_pauseparam(struct net_device *ndev,
@@ -1835,6 +1880,8 @@ static const struct ethtool_ops fec_enet_ethtool_ops = {
 	.get_drvinfo		= fec_enet_get_drvinfo,
 	.nway_reset		= fec_enet_nway_reset,
 	.get_link		= ethtool_op_get_link,
+	.get_ringparam		= fec_enet_get_ringparam,
+	.set_ringparam		= fec_enet_set_ringparam,
 #ifndef CONFIG_M5272
 	.get_pauseparam		= fec_enet_get_pauseparam,
 	.set_pauseparam		= fec_enet_set_pauseparam,
-- 
1.8.3.1