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Add mem_to_banks_detailed (#194)
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* Add `mem_to_banks_detailed`

Adds sideband data in the response path to be managed externally.
`mem_to_banks` now wraps the `mem_to_banks_detailed`.

* `mem_to_banks_detailed`: Rename sideband signals

`atop` renamed to `wuser`
`ersp` renamed to `ruser`
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@micprog
micprog authored Aug 8, 2023
1 parent 33570c5 commit 77c4949
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Showing 6 changed files with 274 additions and 133 deletions.
4 changes: 3 additions & 1 deletion Bender.yml
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Expand Up @@ -98,9 +98,11 @@ sources:
# Level 3
- src/cdc_fifo_gray_clearable.sv
- src/cdc_2phase_clearable.sv
- src/mem_to_banks.sv
- src/mem_to_banks_detailed.sv
- src/stream_arbiter.sv
- src/stream_omega_net.sv
# Level 4
- src/mem_to_banks.sv

- target: simulation
files:
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1 change: 1 addition & 0 deletions README.md
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Expand Up @@ -101,6 +101,7 @@ Please note that cells with status *deprecated* are not to be used for new desig
| `stream_throttle` | Restrict the number of outstanding transfers in a stream. | active | |
| `sub_per_hash` | Substitution-permutation hash function | active | |
| `popcount` | Combinatorial popcount (hamming weight) | active | |
| `mem_to_banks_detailed` | Split memory access over multiple parallel banks with detailed response signals | active | |
| `mem_to_banks` | Split memory access over multiple parallel banks | active | |

### Data Structures
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4 changes: 3 additions & 1 deletion common_cells.core
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Expand Up @@ -81,9 +81,11 @@ filesets:
# Level 3
- src/cdc_fifo_gray_clearable.sv
- src/cdc_2phase_clearable.sv
- src/mem_to_banks.sv
- src/mem_to_banks_detailed.sv
- src/stream_arbiter.sv
- src/stream_omega_net.sv
# Level 4
- src/mem_to_banks.sv
file_type : systemVerilogSource

deprecated:
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169 changes: 39 additions & 130 deletions src/mem_to_banks.sv
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Expand Up @@ -82,135 +82,44 @@ module mem_to_banks #(
input oup_data_t [NumBanks-1:0] bank_rdata_i
);

localparam int unsigned DataBytes = $bits(inp_strb_t);
localparam int unsigned BitsPerBank = $bits(oup_data_t);
localparam int unsigned BytesPerBank = $bits(oup_strb_t);
mem_to_banks_detailed #(
.AddrWidth ( AddrWidth ),
.DataWidth ( DataWidth ),
.WUserWidth ( AtopWidth ),
.RUserWidth ( 1 ),
.NumBanks ( NumBanks ),
.HideStrb ( HideStrb ),
.MaxTrans ( MaxTrans ),
.FifoDepth ( FifoDepth ),
.wuser_t ( atop_t ),
.addr_t ( addr_t ),
.inp_data_t ( inp_data_t ),
.inp_strb_t ( inp_strb_t ),
.oup_data_t ( oup_data_t ),
.oup_strb_t ( oup_strb_t )
) i_mem_to_banks_detailed (
.clk_i,
.rst_ni,
.req_i,
.gnt_o,
.addr_i,
.wdata_i,
.strb_i,
.wuser_i ( atop_i ),
.we_i,
.rvalid_o,
.rdata_o,
.ruser_o (),
.bank_req_o,
.bank_gnt_i,
.bank_addr_o,
.bank_wdata_o,
.bank_strb_o,
.bank_wuser_o ( bank_atop_o ),
.bank_we_o,
.bank_rvalid_i,
.bank_rdata_i,
.bank_ruser_i ('0)
);

typedef struct packed {
addr_t addr;
oup_data_t wdata;
oup_strb_t strb;
atop_t atop;
logic we;
} req_t;

logic req_valid;
logic [NumBanks-1:0] req_ready,
resp_valid, resp_ready;
req_t [NumBanks-1:0] bank_req,
bank_oup;
logic [NumBanks-1:0] bank_req_internal, bank_gnt_internal, zero_strobe, dead_response;
logic dead_write_fifo_full;

function automatic addr_t align_addr(input addr_t addr);
return (addr >> $clog2(DataBytes)) << $clog2(DataBytes);
endfunction

// Handle requests.
assign req_valid = req_i & gnt_o;
for (genvar i = 0; unsigned'(i) < NumBanks; i++) begin : gen_reqs
assign bank_req[i].addr = align_addr(addr_i) + i * BytesPerBank;
assign bank_req[i].wdata = wdata_i[i*BitsPerBank+:BitsPerBank];
assign bank_req[i].strb = strb_i[i*BytesPerBank+:BytesPerBank];
assign bank_req[i].atop = atop_i;
assign bank_req[i].we = we_i;
stream_fifo #(
.FALL_THROUGH ( 1'b1 ),
.DATA_WIDTH ( $bits(req_t) ),
.DEPTH ( FifoDepth ),
.T ( req_t )
) i_ft_reg (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( 1'b0 ),
.usage_o (),
.data_i ( bank_req[i] ),
.valid_i ( req_valid ),
.ready_o ( req_ready[i] ),
.data_o ( bank_oup[i] ),
.valid_o ( bank_req_internal[i] ),
.ready_i ( bank_gnt_internal[i] )
);
assign bank_addr_o[i] = bank_oup[i].addr;
assign bank_wdata_o[i] = bank_oup[i].wdata;
assign bank_strb_o[i] = bank_oup[i].strb;
assign bank_atop_o[i] = bank_oup[i].atop;
assign bank_we_o[i] = bank_oup[i].we;

assign zero_strobe[i] = (bank_oup[i].strb == '0);

if (HideStrb) begin : gen_hide_strb
assign bank_req_o[i] = (bank_oup[i].we && zero_strobe[i]) ? 1'b0 : bank_req_internal[i];
assign bank_gnt_internal[i] = (bank_oup[i].we && zero_strobe[i]) ? 1'b1 : bank_gnt_i[i];
end else begin : gen_legacy_strb
assign bank_req_o[i] = bank_req_internal[i];
assign bank_gnt_internal[i] = bank_gnt_i[i];
end
end

// Grant output if all our requests have been granted.
assign gnt_o = (&req_ready) & (&resp_ready) & !dead_write_fifo_full;

if (HideStrb) begin : gen_dead_write_fifo
fifo_v3 #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( MaxTrans+1 ),
.DATA_WIDTH ( NumBanks )
) i_dead_write_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( 1'b0 ),
.full_o ( dead_write_fifo_full ),
.empty_o (),
.usage_o (),
.data_i ( bank_we_o & zero_strobe ),
.push_i ( req_i & gnt_o ),
.data_o ( dead_response ),
.pop_i ( rvalid_o )
);
end else begin : gen_no_dead_write_fifo
assign dead_response = '0;
assign dead_write_fifo_full = 1'b0;
end

// Handle responses.
for (genvar i = 0; unsigned'(i) < NumBanks; i++) begin : gen_resp_regs
stream_fifo #(
.FALL_THROUGH ( 1'b1 ),
.DATA_WIDTH ( $bits(oup_data_t) ),
.DEPTH ( FifoDepth ),
.T ( oup_data_t )
) i_ft_reg (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( 1'b0 ),
.usage_o (),
.data_i ( bank_rdata_i[i] ),
.valid_i ( bank_rvalid_i[i] ),
.ready_o ( resp_ready[i] ),
.data_o ( rdata_o[i*BitsPerBank+:BitsPerBank] ),
.valid_o ( resp_valid[i] ),
.ready_i ( rvalid_o & !dead_response[i] )
);
end
assign rvalid_o = &(resp_valid | dead_response);

// Assertions
// pragma translate_off
`ifndef VERILATOR
`ifndef SYNTHESIS
initial begin
assume (DataWidth != 0 && (DataWidth & (DataWidth - 1)) == 0)
else $fatal(1, "Data width must be a power of two!");
assume (DataWidth % NumBanks == 0)
else $fatal(1, "Data width must be evenly divisible over banks!");
assume ((DataWidth / NumBanks) % 8 == 0)
else $fatal(1, "Data width of each bank must be divisible into 8-bit bytes!");
end
`endif
`endif
// pragma translate_on
endmodule
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