mlxsw: spectrum: Allow fetch-and-clear of flow counters

For the report_delta-like interface like a previous patch has added for
collection of NH group statistics, it's easiest to read the counter and
have the HW clear it right away. Thus, change mlxsw_sp_flow_counter_get()
to take a bool indicating whether this should be done.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/6a096ede8ee92d5041e3832242c3bbc137198aba.1709901020.git.petrm@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -176,13 +176,15 @@ MLXSW_ITEM32(tx, hdr, fid, 0x08, 16, 16);
 MLXSW_ITEM32(tx, hdr, type, 0x0C, 0, 4);
 
 int mlxsw_sp_flow_counter_get(struct mlxsw_sp *mlxsw_sp,
-			      unsigned int counter_index, u64 *packets,
-			      u64 *bytes)
+			      unsigned int counter_index, bool clear,
+			      u64 *packets, u64 *bytes)
 {
+	enum mlxsw_reg_mgpc_opcode op = clear ? MLXSW_REG_MGPC_OPCODE_CLEAR :
+						MLXSW_REG_MGPC_OPCODE_NOP;
 	char mgpc_pl[MLXSW_REG_MGPC_LEN];
 	int err;
 
-	mlxsw_reg_mgpc_pack(mgpc_pl, counter_index, MLXSW_REG_MGPC_OPCODE_NOP,
+	mlxsw_reg_mgpc_pack(mgpc_pl, counter_index, op,
 			    MLXSW_REG_FLOW_COUNTER_SET_TYPE_PACKETS_BYTES);
 	err = mlxsw_reg_query(mlxsw_sp->core, MLXSW_REG(mgpc), mgpc_pl);
 	if (err)

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -706,8 +706,8 @@ int mlxsw_sp_port_kill_vid(struct net_device *dev,
 int mlxsw_sp_port_vlan_set(struct mlxsw_sp_port *mlxsw_sp_port, u16 vid_begin,
 			   u16 vid_end, bool is_member, bool untagged);
 int mlxsw_sp_flow_counter_get(struct mlxsw_sp *mlxsw_sp,
-			      unsigned int counter_index, u64 *packets,
-			      u64 *bytes);
+			      unsigned int counter_index, bool clear,
+			      u64 *packets, u64 *bytes);
 int mlxsw_sp_flow_counter_alloc(struct mlxsw_sp *mlxsw_sp,
 				unsigned int *p_counter_index);
 void mlxsw_sp_flow_counter_free(struct mlxsw_sp *mlxsw_sp,

drivers/net/ethernet/mellanox/mlxsw/spectrum_acl.c

@@ -1024,7 +1024,7 @@ int mlxsw_sp_acl_rule_get_stats(struct mlxsw_sp *mlxsw_sp,
 	rulei = mlxsw_sp_acl_rule_rulei(rule);
 	if (rulei->counter_valid) {
 		err = mlxsw_sp_flow_counter_get(mlxsw_sp, rulei->counter_index,
-						&current_packets,
+						false, &current_packets,
 						&current_bytes);
 		if (err)
 			return err;

drivers/net/ethernet/mellanox/mlxsw/spectrum_mr_tcam.c

@@ -361,7 +361,7 @@ static int mlxsw_sp_mr_tcam_route_stats(struct mlxsw_sp *mlxsw_sp,
 	struct mlxsw_sp_mr_tcam_route *route = route_priv;
 
 	return mlxsw_sp_flow_counter_get(mlxsw_sp, route->counter_index,
-					 packets, bytes);
+					 false, packets, bytes);
 }
 
 static int

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -2251,7 +2251,7 @@ int mlxsw_sp_neigh_counter_get(struct mlxsw_sp *mlxsw_sp,
 		return -EINVAL;
 
 	return mlxsw_sp_flow_counter_get(mlxsw_sp, neigh_entry->counter_index,
-					 p_counter, NULL);
+					 false, p_counter, NULL);
 }
 
 static struct mlxsw_sp_neigh_entry *
@@ -3186,7 +3186,7 @@ int mlxsw_sp_nexthop_counter_get(struct mlxsw_sp *mlxsw_sp,
 		return -EINVAL;
 
 	return mlxsw_sp_flow_counter_get(mlxsw_sp, nh->counter_index,
-					 p_counter, NULL);
+					 false, p_counter, NULL);
 }
 
 struct mlxsw_sp_nexthop *mlxsw_sp_nexthop_next(struct mlxsw_sp_router *router,