[PATCH V3 net-next 2/6] net: hns3: add support to set/get tx copybreak buf size via ethtool for hns3 driver

[Guangbin Huang <huangguangbin2@xxxxxxxxxx>]

From: Hao Chen <chenhao288@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Guangbin Huang <huangguangbin2@xxxxxxxxxx>
---
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |  4 +-
 .../net/ethernet/hisilicon/hns3/hns3_enet.h   |  2 +
 .../ethernet/hisilicon/hns3/hns3_ethtool.c    | 56 +++++++++++++++++++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index adc54a726661..345dddb2d691 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -5519,8 +5519,8 @@ static int hns3_reset_notify_uninit_enet(struct hnae3_handle *handle)
 	return 0;
 }
 
-static int hns3_reset_notify(struct hnae3_handle *handle,
-			     enum hnae3_reset_notify_type type)
+int hns3_reset_notify(struct hnae3_handle *handle,
+		      enum hnae3_reset_notify_type type)
 {
 	int ret = 0;
 
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
index 6162d9f88e37..eefdcef341d2 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
@@ -705,6 +705,8 @@ void hns3_set_vector_coalesce_tx_ql(struct hns3_enet_tqp_vector *tqp_vector,
 				    u32 ql_value);
 
 void hns3_request_update_promisc_mode(struct hnae3_handle *handle);
+int hns3_reset_notify(struct hnae3_handle *handle,
+		      enum hnae3_reset_notify_type type);
 
 #ifdef CONFIG_HNS3_DCB
 void hns3_dcbnl_setup(struct hnae3_handle *handle);
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 7ea511d59e91..c757e067f31f 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -1691,6 +1691,7 @@ 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) {
@@ -1701,6 +1702,9 @@ 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;
@@ -1709,11 +1713,43 @@ 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;
 
@@ -1731,6 +1767,26 @@ static int hns3_set_tunable(struct net_device *netdev,
 		for (i = h->kinfo.num_tqps; i < h->kinfo.num_tqps * 2; i++)
 			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;
-- 
2.33.0