Skip to content

Commit

Permalink
✨ Add flushable stream arbiter
Browse files Browse the repository at this point in the history
  • Loading branch information
Stefan Mach committed Dec 10, 2018
1 parent 3876fcd commit 35caf1d
Show file tree
Hide file tree
Showing 3 changed files with 74 additions and 16 deletions.
33 changes: 17 additions & 16 deletions README.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -48,22 +48,23 @@ Please note that cells with status *deprecated* are not to be used for new desig

### Data Path Elements

| Name | Description | Status |
|---------------------|------------------------------------------------------------------------------|--------------|
| `binary_to_gray` | Binary to gray code converter | active |
| `find_first_one` | Leading-one finder / leading-zero counter | *deprecated* |
| `gray_to_binary` | Gray code to binary converter | active |
| `lzc` | Leading/trailing-zero counter | active |
| `onehot_to_bin` | One-hot to binary converter | active |
| `pipe_reg_simple` | Pipeline register for arbitrary types | active |
| `rrarbiter` | Round-robin arbiter for req/ack interface with look-ahead | active |
| `spill_register` | Register with ready/valid interface to cut all combinational interface paths | active |
| `stream_arbiter` | Round-robin arbiter for ready/valid stream interface | active |
| `stream_demux` | Ready/valid interface demultiplexer | active |
| `stream_mux` | Ready/valid interface multiplexer | active |
| `stream_register` | Register with ready/valid interface | active |
| `ready_valid_delay` | Randomize or delay ready/valid interface | active |
| `popcount` | Combinatorial popcount (hamming weight) | active |
| Name | Description | Status |
|----------------------------|------------------------------------------------------------------------------|--------------|
| `binary_to_gray` | Binary to gray code converter | active |
| `find_first_one` | Leading-one finder / leading-zero counter | *deprecated* |
| `gray_to_binary` | Gray code to binary converter | active |
| `lzc` | Leading/trailing-zero counter | active |
| `onehot_to_bin` | One-hot to binary converter | active |
| `pipe_reg_simple` | Pipeline register for arbitrary types | active |
| `rrarbiter` | Round-robin arbiter for req/ack interface with look-ahead | active |
| `spill_register` | Register with ready/valid interface to cut all combinational interface paths | active |
| `stream_arbiter` | Round-robin arbiter for ready/valid stream interface | active |
| `stream_arbiter_flushable` | Round-robin arbiter for ready/valid stream interface and flush functionality | active |
| `stream_demux` | Ready/valid interface demultiplexer | active |
| `stream_mux` | Ready/valid interface multiplexer | active |
| `stream_register` | Register with ready/valid interface | active |
| `ready_valid_delay` | Randomize or delay ready/valid interface | active |
| `popcount` | Combinatorial popcount (hamming weight) | active |

### Data Structures

Expand Down
56 changes: 56 additions & 0 deletions src/stream_arbiter_flushable.sv
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,56 @@
// Copyright 2018 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.

// Stream arbiter: Arbitrates a parametrizable number of input streams (i.e., valid-ready
// handshaking with dependency rules as in AXI4) to a single output stream. Once `oup_valid_o` is
// asserted, `oup_data_o` remains invariant until the output handshake has occurred. The
// arbitration scheme is round-robin with "look ahead", see the `rrarbiter` for details.

module stream_arbiter_flushable #(
parameter type DATA_T = logic, // Vivado requires a default value for type parameters.
parameter integer N_INP
) (
input logic clk_i,
input logic rst_ni,
input logic flush_i,

input DATA_T [N_INP-1:0] inp_data_i,
input logic [N_INP-1:0] inp_valid_i,
output logic [N_INP-1:0] inp_ready_o,

output DATA_T oup_data_o,
output logic oup_valid_o,
input logic oup_ready_i
);

logic [$clog2(N_INP)-1:0] idx;

rrarbiter #(
.NUM_REQ (N_INP),
// Lock arbitration decision once the output is valid and until the handshake happens.
.LOCK_IN (1)
) i_arbiter (
.clk_i (clk_i),
.rst_ni (rst_ni),
.flush_i (flush_i),
.en_i (oup_ready_i),
.req_i (inp_valid_i),
.ack_o (inp_ready_o),
// The `vld_o` port of `rrarbiter` combinatorially depends on `en_i`. In the stream protocol,
// a valid may not depend on a ready, so we drive `oup_valid_o` from the `inp_valid_i`s in (1)
// and leave `vld_o` unconnected.
.vld_o (),
.idx_o (idx)
);

assign oup_valid_o = (|inp_valid_i); // (1), see reference above.
assign oup_data_o = inp_data_i[idx];

endmodule
1 change: 1 addition & 0 deletions src_files.yml
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ common_cells_all:
- src/lzc.sv
- src/rrarbiter.sv
- src/stream_arbiter.sv
- src/stream_arbiter_flushable.sv
- src/sync_wedge.sv
- src/sync.sv
- src/clk_div.sv
Expand Down

0 comments on commit 35caf1d

Please sign in to comment.