mlx5: Implement SyncE support using DPLL infrastructure

This is unfinished. Will change according to DPLL kernel API changes.
DPLL infrastructure is not yet merged upstream, it is maintained
out-of-tree here: https://github.com/vvfedorenko/linux-dpll/commits/net-next-dpll

Signed-off-by: Jiri Pirko <jiri@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/Kconfig

@@ -188,3 +188,11 @@ config MLX5_SF_MANAGER
 	port is managed through devlink.  A subfunction supports RDMA, netdevice
 	and vdpa device. It is similar to a SRIOV VF but it doesn't require
 	SRIOV support.
+
+config MLX5_DPLL
+	tristate "Mellanox 5th generation network adapters (ConnectX series) DPLL support"
+	depends on NETDEVICES && ETHERNET && PCI && MLX5_CORE
+	select DPLL
+	help
+	  DPLL support in Mellanox Technologies ConnectX NICs.
+

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -121,3 +121,6 @@ mlx5_core-$(CONFIG_MLX5_SF) += sf/vhca_event.o sf/dev/dev.o sf/dev/driver.o irq_
 # SF manager
 #
 mlx5_core-$(CONFIG_MLX5_SF_MANAGER) += sf/cmd.o sf/hw_table.o sf/devlink.o
+
+obj-$(CONFIG_MLX5_DPLL) += mlx5_dpll.o
+mlx5_dpll-y :=	dpll.o

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

@@ -221,6 +221,14 @@ static bool is_ib_enabled(struct mlx5_core_dev *dev)
 	return err ? false : val.vbool;
 }
 
+static bool is_dpll_supported(struct mlx5_core_dev *dev)
+{
+	if (!IS_ENABLED(CONFIG_MLX5_DPLL))
+		return false;
+
+	return true;
+}
+
 enum {
 	MLX5_INTERFACE_PROTOCOL_ETH,
 	MLX5_INTERFACE_PROTOCOL_ETH_REP,
@@ -230,6 +238,8 @@ enum {
 	MLX5_INTERFACE_PROTOCOL_MPIB,
 
 	MLX5_INTERFACE_PROTOCOL_VNET,
+
+	MLX5_INTERFACE_PROTOCOL_DPLL,
 };
 
 static const struct mlx5_adev_device {
@@ -252,6 +262,8 @@ static const struct mlx5_adev_device {
 					   .is_supported = &is_ib_rep_supported },
 	[MLX5_INTERFACE_PROTOCOL_MPIB] = { .suffix = "multiport",
 					   .is_supported = &is_mp_supported },
+	[MLX5_INTERFACE_PROTOCOL_DPLL] = { .suffix = "dpll",
+					   .is_supported = &is_dpll_supported },
 };
 
 int mlx5_adev_idx_alloc(void)