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wip: Multi-ID meta buffer
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@fischeti
fischeti committed Jun 7, 2024
1 parent 127d994 commit ea4dd45
Showing 1 changed file with 117 additions and 39 deletions.
156 changes: 117 additions & 39 deletions hw/floo_meta_buffer.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
module floo_meta_buffer #(
/// Maximum number of non-atomic outstanding requests
parameter int MaxTxns = 32'd0,
/// Number of unique non-atomic IDs
parameter int MaxUniqueIDs = 32'd1,
/// Enable support for atomics
parameter bit AtopSupport = 1'b1,
/// Number of outstanding atomic requests
Expand All @@ -31,6 +33,10 @@ module floo_meta_buffer #(
localparam type id_in_t = logic[IdInWidth-1:0],
/// ID type for outgoing responses
localparam type id_out_t = logic[IdOutWidth-1:0],
/// Minimum IdWidth
localparam int IdMinWidth = (IdInWidth < IdOutWidth)? IdInWidth : IdOutWidth,
/// Minimum ID type
localparam type id_t = logic[IdMinWidth-1:0],
/// Constant ID for non-atomic requests
localparam id_out_t NonAtomicId = '1
) (
Expand All @@ -56,41 +62,112 @@ module floo_meta_buffer #(
buf_t no_atop_r_buf, no_atop_b_buf;
buf_t [MaxAtomicTxns-1:0] atop_r_buf, atop_b_buf;

fifo_v3 #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( MaxTxns ),
.dtype ( buf_t )
) i_ar_no_atop_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( test_enable_i ),
.full_o ( ar_no_atop_buf_full ),
.empty_o ( ),
.usage_o ( ),
.data_i ( ar_buf_i ),
.push_i ( ar_no_atop_push ),
.data_o ( no_atop_r_buf ),
.pop_i ( ar_no_atop_pop )
);

fifo_v3 #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( MaxTxns ),
.dtype ( buf_t )
) i_aw_no_atop_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( test_enable_i ),
.full_o ( aw_no_atop_buf_full ),
.empty_o ( ),
.usage_o ( ),
.data_i ( aw_buf_i ),
.push_i ( aw_no_atop_push ),
.data_o ( no_atop_b_buf ),
.pop_i ( aw_no_atop_pop )
);
id_t no_atop_aw_req_id, no_atop_ar_req_id;

if (MaxUniqueIDs == 1) begin : gen_no_atop_fifos

assign no_atop_aw_req_id = NonAtomicId;
assign no_atop_ar_req_id = NonAtomicId;

fifo_v3 #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( MaxTxns ),
.dtype ( buf_t )
) i_ar_no_atop_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( test_enable_i ),
.full_o ( ar_no_atop_buf_full ),
.empty_o ( ),
.usage_o ( ),
.data_i ( ar_buf_i ),
.push_i ( ar_no_atop_push ),
.data_o ( no_atop_r_buf ),
.pop_i ( ar_no_atop_pop )
);

fifo_v3 #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( MaxTxns ),
.dtype ( buf_t )
) i_aw_no_atop_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( test_enable_i ),
.full_o ( aw_no_atop_buf_full ),
.empty_o ( ),
.usage_o ( ),
.data_i ( aw_buf_i ),
.push_i ( aw_no_atop_push ),
.data_o ( no_atop_b_buf ),
.pop_i ( aw_no_atop_pop )
);

end else begin : gen_no_atop_id_queue

logic b_outp_gnt, b_oup_data_valid;
logic r_outp_gnt, r_oup_data_valid;

assign no_atop_aw_req_id = NonAtomicId - id_t'(axi_req_i.aw.id);
assign no_atop_ar_req_id = NonAtomicId - id_t'(axi_req_i.ar.id);

id_queue #(
.ID_WIDTH (IdMinWidth),
.CAPACITY (MaxTxns),
.FULL_BW (1'b0),
.data_t (buf_t)
) i_aw_no_atop_id_queue (
.clk_i,
.rst_ni,
.inp_id_i (id_t'(axi_req_i.aw.id)),
.inp_data_i (aw_buf_i),
.inp_req_i (aw_no_atop_push),
.inp_gnt_o (aw_no_atop_buf_full),
.exists_data_i ('0),
.exists_mask_i ('0),
.exists_req_i ('0),
.exists_o (),
.exists_gnt_o (),
.oup_id_i (axi_rsp_i.b.id),
.oup_pop_i (aw_no_atop_pop),
.oup_req_i (axi_rsp_i.b_valid),
.oup_data_o (no_atop_b_buf),
.oup_data_valid_o(b_oup_data_valid),
.oup_gnt_o (b_outp_gnt)
);

id_queue #(
.ID_WIDTH (IdMinWidth),
.CAPACITY (MaxTxns),
.FULL_BW (1'b0),
.data_t (buf_t)
) i_ar_no_atop_id_queue (
.clk_i,
.rst_ni,
.inp_id_i (id_t'(axi_req_i.ar.id)),
.inp_data_i (ar_buf_i),
.inp_req_i (ar_no_atop_push),
.inp_gnt_o (ar_no_atop_buf_full),
.exists_data_i ('0),
.exists_mask_i ('0),
.exists_req_i ('0),
.exists_o (),
.exists_gnt_o (),
.oup_id_i (axi_rsp_i.r.id),
.oup_pop_i (ar_no_atop_pop),
.oup_req_i (axi_rsp_i.r_valid),
.oup_data_o (no_atop_b_buf),
.oup_data_valid_o(r_oup_data_valid),
.oup_gnt_o (r_oup_gnt)
);

`ASSERT(NoBResponseIdQueue, axi_rsp_i.b_valid -> (b_oup_data_valid && b_outp_gnt),
"Meta data for B response must exist in Id Queue!")
`ASSERT(NoRResponseIdQueue, axi_rsp_i.r_valid -> (r_oup_data_valid && r_oup_gnt),
"Meta data for R response must exist in Id Queue!")
end

// Non-atomic AR's
assign ar_no_atop_push = axi_req_o.ar_valid && axi_rsp_i.ar_ready;
Expand All @@ -101,8 +178,8 @@ module floo_meta_buffer #(
assign aw_no_atop_push = axi_req_o.aw_valid && axi_rsp_i.aw_ready && !is_atop_aw;
assign aw_no_atop_pop = axi_rsp_o.b_valid && axi_req_i.b_ready && !is_atop_b_rsp;

assign is_atop_r_rsp = axi_rsp_i.r_valid && axi_rsp_i.r.id != NonAtomicId;
assign is_atop_b_rsp = axi_rsp_i.b_valid && axi_rsp_i.b.id != NonAtomicId;
assign is_atop_r_rsp = axi_rsp_i.r_valid && axi_rsp_i.r.id > MaxAtomicTxns;
assign is_atop_b_rsp = axi_rsp_i.b_valid && axi_rsp_i.b.id > MaxAtomicTxns;
`ASSERT(NoAtopSupport, !(!AtopSupport && is_atop_aw),
"Atomics not supported, but atomic request received!")

Expand Down Expand Up @@ -188,8 +265,8 @@ module floo_meta_buffer #(
axi_req_o = axi_req_i;
axi_rsp_o = axi_rsp_i;
// Use fixed ID for non-atomic requests and unique ID for atomic requests
axi_req_o.ar.id = NonAtomicId;
axi_req_o.aw.id = (is_atop_aw && AtopSupport)? atop_req_id : NonAtomicId;
axi_req_o.ar.id = no_atop_ar_req_id;
axi_req_o.aw.id = (is_atop_aw && AtopSupport)? atop_req_id : no_atop_aw_req_id;
// Use original, buffered ID again for responses
axi_rsp_o.r.id = (is_atop_r_rsp && AtopSupport)?
atop_r_buf[axi_rsp_i.r.id] : no_atop_r_buf.id;
Expand All @@ -204,5 +281,6 @@ module floo_meta_buffer #(
end
end

`ASSERT_INIT(InvalidMaxUniqueIDs, MaxUniqueIDs > 0)

endmodule

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