Add stream_join_dynamic

Bender.yml

@@ -53,7 +53,7 @@ sources:
   - src/stream_filter.sv
   - src/stream_fork.sv
   - src/stream_intf.sv
-  - src/stream_join.sv
+  - src/stream_join_dynamic.sv
   - src/stream_mux.sv
   - src/stream_throttle.sv
   - src/lossy_valid_to_stream.sv
@@ -84,6 +84,7 @@ sources:
   - src/stream_delay.sv
   - src/stream_fifo.sv
   - src/stream_fork_dynamic.sv
+  - src/stream_join.sv
   - src/clk_mux_glitch_free.sv
   # Level 2
   - src/cdc_reset_ctrlr.sv

README.md

@@ -89,6 +89,7 @@ Please note that cells with status *deprecated* are not to be used for new desig
 | `stream_demux`             | Ready/valid interface demultiplexer                                                                       | active       |               |
 | `lossy_valid_to_stream`    | Convert Valid-only to ready/valid by updating in-flight transaction                                       | active       |               |
 | `stream_join`              | Ready/valid handshake join multiple to one common                                                         | active       |               |
+| `stream_join_dynamic`      | Ready/valid handshake join multiple to one common, dynamically configurable subset selection              | active       |               |
 | `stream_mux`               | Ready/valid interface multiplexer                                                                         | active       |               |
 | `stream_register`          | Register with ready/valid interface                                                                       | active       |               |
 | `stream_fork`              | Ready/valid fork                                                                                          | active       |               |

src/stream_join.sv

@@ -28,16 +28,14 @@ module stream_join #(
   input  logic              oup_ready_i
 );
 
-  assign oup_valid_o = (&inp_valid_i);
-  for (genvar i = 0; i < N_INP; i++) begin : gen_inp_ready
-    assign inp_ready_o[i] = oup_valid_o & oup_ready_i;
-  end
+  stream_join_dynamic #(
+    .N_INP(N_INP)
+  ) i_stream_join_dynamic (
+    .inp_valid_i(inp_valid_i),
+    .inp_ready_o(inp_ready_o),
+    .sel_i      ({N_INP{1'b1}}),
+    .oup_valid_o(oup_valid_o),
+    .oup_ready_i(oup_ready_i)
+  );
 
-// pragma translate_off
-`ifndef VERILATOR
-  initial begin: p_assertions
-    assert (N_INP >= 1) else $fatal(1, "N_INP must be at least 1!");
-  end
-`endif
-// pragma translate_on
 endmodule

src/stream_join_dynamic.sv

@@ -0,0 +1,47 @@
+// Copyright 2020 ETH Zurich and University of Bologna.
+// Copyright and related rights are licensed under the Solderpad Hardware
+// License, Version 0.51 (the "License"); you may not use this file except in
+// compliance with the License. You may obtain a copy of the License at
+// http://solderpad.org/licenses/SHL-0.51. Unless required by applicable law
+// or agreed to in writing, software, hardware and materials distributed under
+// this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+// Authors:
+// - Luca Colagrande <[email protected]>
+
+// Stream join dynamic: Joins a parametrizable number of input streams (i.e. valid-ready
+// handshaking with dependency rules as in AXI4) to a single output stream. The subset of streams
+// to join can be configured dynamically via `sel_i`. The output handshake happens only after
+// there has been a handshake. The data channel flows outside of this module.
+module stream_join_dynamic #(
+  /// Number of input streams
+  parameter int unsigned N_INP = 32'd0 // Synopsys DC requires a default value for parameters.
+) (
+  /// Input streams valid handshakes
+  input  logic [N_INP-1:0] inp_valid_i,
+  /// Input streams ready handshakes
+  output logic [N_INP-1:0] inp_ready_o,
+  /// Selection mask for the output handshake
+  input  logic [N_INP-1:0] sel_i,
+  /// Output stream valid handshake
+  output logic             oup_valid_o,
+  /// Output stream ready handshake
+  input  logic             oup_ready_i
+);
+
+  // Corner case when `sel_i` is all 0s should not generate valid
+  assign oup_valid_o = &(inp_valid_i | ~sel_i) && |sel_i;
+  for (genvar i = 0; i < N_INP; i++) begin : gen_inp_ready
+    assign inp_ready_o[i] = oup_valid_o & oup_ready_i;
+  end
+
+// pragma translate_off
+`ifndef VERILATOR
+  initial begin: p_assertions
+    assert (N_INP >= 1) else $fatal(1, "N_INP must be at least 1!");
+  end
+`endif
+// pragma translate_on
+endmodule

src_files.yml

@@ -37,6 +37,7 @@ common_cells_all:
     - src/stream_fork.sv
     - src/stream_intf.sv
     - src/stream_join.sv
+    - src/stream_join_dynamic.sv
     - src/stream_mux.sv
     - src/stream_throttle.sv
     - src/sub_per_hash.sv