net/mlx5e: Receive buffer support for DCBX

Add dcbnl's set/get buffer configuration callback that allows user to
set/get buffer size configuration and priority to buffer mapping.

By default, firmware controls receive buffer configuration and priority
of buffer mapping based on the changes in pfc settings. When set buffer
call back is triggered, the buffer configuration changes to manual mode.

The manual mode means mlx5 driver will adjust the buffer configuration
accordingly based on the changes in pfc settings.

ConnectX buffer stride is 128 Bytes. If the buffer size is not multiple
of 128, the buffer size will be rounded down to the nearest multiple of
128.

Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -278,6 +278,7 @@ struct mlx5e_dcbx {
 	u8                         cap;
 
 	/* Buffer configuration */
+	bool                       manual_buffer;
 	u32                        cable_len;
 	u32                        xoff;
 };

drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c

@@ -32,15 +32,18 @@
 #include <linux/device.h>
 #include <linux/netdevice.h>
 #include "en.h"
-
-#define MLX5E_MAX_PRIORITY 8
+#include "en/port.h"
+#include "en/port_buffer.h"
 
 #define MLX5E_100MB (100000)
 #define MLX5E_1GB   (1000000)
 
 #define MLX5E_CEE_STATE_UP    1
 #define MLX5E_CEE_STATE_DOWN  0
 
+/* Max supported cable length is 1000 meters */
+#define MLX5E_MAX_CABLE_LENGTH 1000
+
 enum {
 	MLX5E_VENDOR_TC_GROUP_NUM = 7,
 	MLX5E_LOWEST_PRIO_GROUP   = 0,
@@ -338,6 +341,9 @@ static int mlx5e_dcbnl_ieee_getpfc(struct net_device *dev,
 		pfc->indications[i] = PPORT_PER_PRIO_GET(pstats, i, rx_pause);
 	}
 
+	if (MLX5_BUFFER_SUPPORTED(mdev))
+		pfc->delay = priv->dcbx.cable_len;
+
 	return mlx5_query_port_pfc(mdev, &pfc->pfc_en, NULL);
 }
 
@@ -346,16 +352,39 @@ static int mlx5e_dcbnl_ieee_setpfc(struct net_device *dev,
 {
 	struct mlx5e_priv *priv = netdev_priv(dev);
 	struct mlx5_core_dev *mdev = priv->mdev;
+	u32 old_cable_len = priv->dcbx.cable_len;
+	struct ieee_pfc pfc_new;
+	u32 changed = 0;
 	u8 curr_pfc_en;
-	int ret;
+	int ret = 0;
 
+	/* pfc_en */
 	mlx5_query_port_pfc(mdev, &curr_pfc_en, NULL);
+	if (pfc->pfc_en != curr_pfc_en) {
+		ret = mlx5_set_port_pfc(mdev, pfc->pfc_en, pfc->pfc_en);
+		if (ret)
+			return ret;
+		mlx5_toggle_port_link(mdev);
+		changed |= MLX5E_PORT_BUFFER_PFC;
+	}
 
-	if (pfc->pfc_en == curr_pfc_en)
-		return 0;
+	if (pfc->delay &&
+	    pfc->delay < MLX5E_MAX_CABLE_LENGTH &&
+	    pfc->delay != priv->dcbx.cable_len) {
+		priv->dcbx.cable_len = pfc->delay;
+		changed |= MLX5E_PORT_BUFFER_CABLE_LEN;
+	}
 
-	ret = mlx5_set_port_pfc(mdev, pfc->pfc_en, pfc->pfc_en);
-	mlx5_toggle_port_link(mdev);
+	if (MLX5_BUFFER_SUPPORTED(mdev)) {
+		pfc_new.pfc_en = (changed & MLX5E_PORT_BUFFER_PFC) ? pfc->pfc_en : curr_pfc_en;
+		if (priv->dcbx.manual_buffer)
+			ret = mlx5e_port_manual_buffer_config(priv, changed,
+							      dev->mtu, &pfc_new,
+							      NULL, NULL);
+
+		if (ret && (changed & MLX5E_PORT_BUFFER_CABLE_LEN))
+			priv->dcbx.cable_len = old_cable_len;
+	}
 
 	if (!ret) {
 		mlx5e_dbg(HW, priv,
@@ -873,6 +902,90 @@ static void mlx5e_dcbnl_setpfcstate(struct net_device *netdev, u8 state)
 	cee_cfg->pfc_enable = state;
 }
 
+static int mlx5e_dcbnl_getbuffer(struct net_device *dev,
+				 struct dcbnl_buffer *dcb_buffer)
+{
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	struct mlx5_core_dev *mdev = priv->mdev;
+	struct mlx5e_port_buffer port_buffer;
+	u8 buffer[MLX5E_MAX_PRIORITY];
+	int i, err;
+
+	if (!MLX5_BUFFER_SUPPORTED(mdev))
+		return -EOPNOTSUPP;
+
+	err = mlx5e_port_query_priority2buffer(mdev, buffer);
+	if (err)
+		return err;
+
+	for (i = 0; i < MLX5E_MAX_PRIORITY; i++)
+		dcb_buffer->prio2buffer[i] = buffer[i];
+
+	err = mlx5e_port_query_buffer(priv, &port_buffer);
+	if (err)
+		return err;
+
+	for (i = 0; i < MLX5E_MAX_BUFFER; i++)
+		dcb_buffer->buffer_size[i] = port_buffer.buffer[i].size;
+	dcb_buffer->total_size = port_buffer.port_buffer_size;
+
+	return 0;
+}
+
+static int mlx5e_dcbnl_setbuffer(struct net_device *dev,
+				 struct dcbnl_buffer *dcb_buffer)
+{
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	struct mlx5_core_dev *mdev = priv->mdev;
+	struct mlx5e_port_buffer port_buffer;
+	u8 old_prio2buffer[MLX5E_MAX_PRIORITY];
+	u32 *buffer_size = NULL;
+	u8 *prio2buffer = NULL;
+	u32 changed = 0;
+	int i, err;
+
+	if (!MLX5_BUFFER_SUPPORTED(mdev))
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < DCBX_MAX_BUFFERS; i++)
+		mlx5_core_dbg(mdev, "buffer[%d]=%d\n", i, dcb_buffer->buffer_size[i]);
+
+	for (i = 0; i < MLX5E_MAX_PRIORITY; i++)
+		mlx5_core_dbg(mdev, "priority %d buffer%d\n", i, dcb_buffer->prio2buffer[i]);
+
+	err = mlx5e_port_query_priority2buffer(mdev, old_prio2buffer);
+	if (err)
+		return err;
+
+	for (i = 0; i < MLX5E_MAX_PRIORITY; i++) {
+		if (dcb_buffer->prio2buffer[i] != old_prio2buffer[i]) {
+			changed |= MLX5E_PORT_BUFFER_PRIO2BUFFER;
+			prio2buffer = dcb_buffer->prio2buffer;
+			break;
+		}
+	}
+
+	err = mlx5e_port_query_buffer(priv, &port_buffer);
+	if (err)
+		return err;
+
+	for (i = 0; i < MLX5E_MAX_BUFFER; i++) {
+		if (port_buffer.buffer[i].size != dcb_buffer->buffer_size[i]) {
+			changed |= MLX5E_PORT_BUFFER_SIZE;
+			buffer_size = dcb_buffer->buffer_size;
+			break;
+		}
+	}
+
+	if (!changed)
+		return 0;
+
+	priv->dcbx.manual_buffer = true;
+	err = mlx5e_port_manual_buffer_config(priv, changed, dev->mtu, NULL,
+					      buffer_size, prio2buffer);
+	return err;
+}
+
 const struct dcbnl_rtnl_ops mlx5e_dcbnl_ops = {
 	.ieee_getets	= mlx5e_dcbnl_ieee_getets,
 	.ieee_setets	= mlx5e_dcbnl_ieee_setets,
@@ -884,6 +997,8 @@ const struct dcbnl_rtnl_ops mlx5e_dcbnl_ops = {
 	.ieee_delapp    = mlx5e_dcbnl_ieee_delapp,
 	.getdcbx	= mlx5e_dcbnl_getdcbx,
 	.setdcbx	= mlx5e_dcbnl_setdcbx,
+	.dcbnl_getbuffer = mlx5e_dcbnl_getbuffer,
+	.dcbnl_setbuffer = mlx5e_dcbnl_setbuffer,
 
 /* CEE interfaces */
 	.setall         = mlx5e_dcbnl_setall,
@@ -1091,5 +1206,8 @@ void mlx5e_dcbnl_initialize(struct mlx5e_priv *priv)
 	if (priv->dcbx.mode == MLX5E_DCBX_PARAM_VER_OPER_HOST)
 		priv->dcbx.cap |= DCB_CAP_DCBX_HOST;
 
+	priv->dcbx.manual_buffer = false;
+	priv->dcbx.cable_len = MLX5E_DEFAULT_CABLE_LEN;
+
 	mlx5e_ets_init(priv);
 }