net: hns3: add support to set/get tx copybreak buf size via ethtool for hns3 driver

Tx copybreak buf size is used for tx copybreak feature, the feature is
used for small size packet or frag. It adds a queue based tx shared
bounce buffer to memcpy the small packet when the len of xmitted skb is
below tx_copybreak(value to distinguish small size and normal size),
and reduce the overhead of dma map and unmap when IOMMU is on.

Support setting it via ethtool --set-tunable parameter and getting
it via ethtool --get-tunable parameter.

Signed-off-by: Hao Chen <chenhao288@hisilicon.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index c8442b86df94..9a816dbec613 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -1695,6 +1695,7 @@ static int hns3_get_tunable(struct net_device *netdev,
 			    void *data)
 {
 	struct hns3_nic_priv *priv = netdev_priv(netdev);
+	struct hnae3_handle *h = priv->ae_handle;
 	int ret = 0;
 
 	switch (tuna->id) {
@@ -1705,6 +1706,9 @@ static int hns3_get_tunable(struct net_device *netdev,
 	case ETHTOOL_RX_COPYBREAK:
 		*(u32 *)data = priv->rx_copybreak;
 		break;
+	case ETHTOOL_TX_COPYBREAK_BUF_SIZE:
+		*(u32 *)data = h->kinfo.tx_spare_buf_size;
+		break;
 	default:
 		ret = -EOPNOTSUPP;
 		break;
@@ -1713,11 +1717,43 @@ static int hns3_get_tunable(struct net_device *netdev,
 	return ret;
 }
 
+static int hns3_set_tx_spare_buf_size(struct net_device *netdev,
+				      u32 data)
+{
+	struct hns3_nic_priv *priv = netdev_priv(netdev);
+	struct hnae3_handle *h = priv->ae_handle;
+	int ret;
+
+	if (hns3_nic_resetting(netdev))
+		return -EBUSY;
+
+	h->kinfo.tx_spare_buf_size = data;
+
+	ret = hns3_reset_notify(h, HNAE3_DOWN_CLIENT);
+	if (ret)
+		return ret;
+
+	ret = hns3_reset_notify(h, HNAE3_UNINIT_CLIENT);
+	if (ret)
+		return ret;
+
+	ret = hns3_reset_notify(h, HNAE3_INIT_CLIENT);
+	if (ret)
+		return ret;
+
+	ret = hns3_reset_notify(h, HNAE3_UP_CLIENT);
+	if (ret)
+		hns3_reset_notify(h, HNAE3_UNINIT_CLIENT);
+
+	return ret;
+}
+
 static int hns3_set_tunable(struct net_device *netdev,
 			    const struct ethtool_tunable *tuna,
 			    const void *data)
 {
 	struct hns3_nic_priv *priv = netdev_priv(netdev);
+	u32 old_tx_spare_buf_size, new_tx_spare_buf_size;
 	struct hnae3_handle *h = priv->ae_handle;
 	int i, ret = 0;
 
@@ -1736,6 +1772,26 @@ static int hns3_set_tunable(struct net_device *netdev,
 			priv->ring[i].rx_copybreak = priv->rx_copybreak;
 
 		break;
+	case ETHTOOL_TX_COPYBREAK_BUF_SIZE:
+		old_tx_spare_buf_size = h->kinfo.tx_spare_buf_size;
+		new_tx_spare_buf_size = *(u32 *)data;
+		ret = hns3_set_tx_spare_buf_size(netdev, new_tx_spare_buf_size);
+		if (ret) {
+			int ret1;
+
+			netdev_warn(netdev,
+				    "change tx spare buf size fail, revert to old value\n");
+			ret1 = hns3_set_tx_spare_buf_size(netdev,
+							  old_tx_spare_buf_size);
+			if (ret1) {
+				netdev_err(netdev,
+					   "revert to old tx spare buf size fail\n");
+				return ret1;
+			}
+
+			return ret;
+		}
+		break;
 	default:
 		ret = -EOPNOTSUPP;
 		break;