From c415fc6a42a37acc01343c412461be80aa2f81d0 Mon Sep 17 00:00:00 2001
From: Luca Colagrande <luca.colagrande3@gmail.com>
Date: Fri, 12 Aug 2022 09:53:31 +0200
Subject: [PATCH] Add stream_join_dynamic

---
 Bender.yml                 |  1 +
 src/stream_join.sv         | 20 ++++++++--------
 src/stream_join_dynamic.sv | 47 ++++++++++++++++++++++++++++++++++++++
 src_files.yml              |  1 +
 4 files changed, 58 insertions(+), 11 deletions(-)
 create mode 100644 src/stream_join_dynamic.sv

diff --git a/Bender.yml b/Bender.yml
index ba296c10..c35cdfae 100644
--- a/Bender.yml
+++ b/Bender.yml
@@ -54,6 +54,7 @@ sources:
   - 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
diff --git a/src/stream_join.sv b/src/stream_join.sv
index 2f210bc7..6e19916f 100644
--- a/src/stream_join.sv
+++ b/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
diff --git a/src/stream_join_dynamic.sv b/src/stream_join_dynamic.sv
new file mode 100644
index 00000000..e3c22b83
--- /dev/null
+++ b/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 <colluca@iis.ee.ethz.ch>
+
+// 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
diff --git a/src_files.yml b/src_files.yml
index 64204a50..b3741b61 100644
--- a/src_files.yml
+++ b/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