net/mlx5: SD, Implement basic query and instantiation

Add implementation for querying the MPIR register for Socket-Direct
attributes, and instantiating a SD struct accordingly.
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c

@@ -3,6 +3,8 @@
 
 #include "lib/sd.h"
 #include "mlx5_core.h"
+#include "lib/mlx5.h"
+#include <linux/mlx5/vport.h>
 
 #define sd_info(__dev, format, ...) \
 	dev_info((__dev)->device, "Socket-Direct: " format, ##__VA_ARGS__)
@@ -10,11 +12,18 @@
 	dev_warn((__dev)->device, "Socket-Direct: " format, ##__VA_ARGS__)
 
 struct mlx5_sd {
+	u32 group_id;
+	u8 host_buses;
 };
 
 static int mlx5_sd_get_host_buses(struct mlx5_core_dev *dev)
 {
-	return 1;
+	struct mlx5_sd *sd = mlx5_get_sd(dev);
+
+	if (!sd)
+		return 1;
+
+	return sd->host_buses;
 }
 
 struct mlx5_core_dev *
@@ -43,13 +52,109 @@ struct mlx5_core_dev *mlx5_sd_ch_ix_get_dev(struct mlx5_core_dev *primary, int c
 	return mlx5_sd_primary_get_peer(primary, mdev_idx);
 }
 
+static bool mlx5_sd_is_supported(struct mlx5_core_dev *dev, u8 host_buses)
+{
+	/* Feature is currently implemented for PFs only */
+	if (!mlx5_core_is_pf(dev))
+		return false;
+
+	/* Honor the SW implementation limit */
+	if (host_buses > MLX5_SD_MAX_GROUP_SZ)
+		return false;
+
+	return true;
+}
+
+static int mlx5_query_sd(struct mlx5_core_dev *dev, bool *sdm,
+			 u8 *host_buses, u8 *sd_group)
+{
+	u32 out[MLX5_ST_SZ_DW(mpir_reg)];
+	int err;
+
+	err = mlx5_query_mpir_reg(dev, out);
+	if (err)
+		return err;
+
+	err = mlx5_query_nic_vport_sd_group(dev, sd_group);
+	if (err)
+		return err;
+
+	*sdm = MLX5_GET(mpir_reg, out, sdm);
+	*host_buses = MLX5_GET(mpir_reg, out, host_buses);
+
+	return 0;
+}
+
+static u32 mlx5_sd_group_id(struct mlx5_core_dev *dev, u8 sd_group)
+{
+	return (u32)((MLX5_CAP_GEN(dev, native_port_num) << 8) | sd_group);
+}
+
+static int sd_init(struct mlx5_core_dev *dev)
+{
+	u8 host_buses, sd_group;
+	struct mlx5_sd *sd;
+	u32 group_id;
+	bool sdm;
+	int err;
+
+	err = mlx5_query_sd(dev, &sdm, &host_buses, &sd_group);
+	if (err)
+		return err;
+
+	if (!sdm)
+		return 0;
+
+	if (!sd_group)
+		return 0;
+
+	group_id = mlx5_sd_group_id(dev, sd_group);
+
+	if (!mlx5_sd_is_supported(dev, host_buses)) {
+		sd_warn(dev, "can't support requested netdev combining for group id 0x%x), skipping\n",
+			group_id);
+		return 0;
+	}
+
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+	if (!sd)
+		return -ENOMEM;
+
+	sd->host_buses = host_buses;
+	sd->group_id = group_id;
+
+	mlx5_set_sd(dev, sd);
+
+	return 0;
+}
+
+static void sd_cleanup(struct mlx5_core_dev *dev)
+{
+	struct mlx5_sd *sd = mlx5_get_sd(dev);
+
+	mlx5_set_sd(dev, NULL);
+	kfree(sd);
+}
+
 int mlx5_sd_init(struct mlx5_core_dev *dev)
 {
+	int err;
+
+	err = sd_init(dev);
+	if (err)
+		return err;
+
 	return 0;
 }
 
 void mlx5_sd_cleanup(struct mlx5_core_dev *dev)
 {
+	struct mlx5_sd *sd = mlx5_get_sd(dev);
+
+	if (!sd)
+		return;
+
+	sd_cleanup(dev);
 }
 
 struct auxiliary_device *mlx5_sd_get_adev(struct mlx5_core_dev *dev,