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rtl(axi_dw_downsizer): hold BRESP stable while BVALID asserted #451

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rtl(axi_dw_downsizer): hold BRESP stable while BVALID asserted #451

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15 changes: 8 additions & 7 deletions src/axi_dw_downsizer.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -688,8 +688,8 @@ module axi_dw_downsizer #(
.rst_ni (rst_ni ),
.flush_i (1'b0 ),
.testmode_i(1'b0 ),
.data_i (forward_b_beat_i ),
.push_i (forward_b_beat_push ),
.data_i (forward_b_beat_i ),
.full_o (forward_b_beat_full ),
.data_o (forward_b_beat_o ),
.pop_i (forward_b_beat_pop ),
Expand Down Expand Up @@ -729,12 +729,8 @@ module axi_dw_downsizer #(
w_data = '0;

// B Channel (No latency)
if (mst_resp.b_valid) begin
// Merge response of this burst with prior one according to precedence rules.
w_req_d.burst_resp = axi_pkg::resp_precedence(w_req_q.burst_resp, mst_resp.b.resp);
end
slv_resp_o.b = mst_resp.b ;
slv_resp_o.b.resp = w_req_d.burst_resp;
slv_resp_o.b.resp = axi_pkg::resp_precedence(w_req_q.burst_resp, mst_resp.b.resp);

// Each write transaction might trigger several B beats on the master (narrow) side.
// Only forward the last B beat of each transaction.
Expand All @@ -745,12 +741,17 @@ module axi_dw_downsizer #(
// Got an ack on the B channel. Pop transaction.
if (mst_req.b_ready && mst_resp.b_valid) begin
forward_b_beat_pop = 1'b1;
w_req_d.burst_resp = axi_pkg::RESP_EXOKAY;
end
end else begin
// Otherwise, just acknowlegde the B beats
slv_resp_o.b_valid = 1'b0 ;
mst_req.b_ready = 1'b1 ;
forward_b_beat_pop = mst_resp.b_valid;

if (mst_req.b_ready && mst_resp.b_valid) begin
w_req_d.burst_resp = axi_pkg::resp_precedence(w_req_q.burst_resp, mst_resp.b.resp);
end
end

// Got a grant on the AW channel
Expand Down Expand Up @@ -845,7 +846,6 @@ module axi_dw_downsizer #(
w_req_d.aw = '0 ;
w_req_d.aw_valid = 1'b0 ;
w_req_d.aw_throw_error = 1'b0 ;
w_req_d.burst_resp = axi_pkg::RESP_EXOKAY;

if (!forward_b_beat_full) begin
if (slv_req_i.aw_valid && slv_req_i.aw.atop[axi_pkg::ATOP_R_RESP]) begin // ATOP with an R response
Expand Down Expand Up @@ -937,6 +937,7 @@ module axi_dw_downsizer #(
if (!rst_ni) begin
w_state_q <= W_IDLE;
w_req_q <= '0 ;
w_req_q.burst_resp <= axi_pkg::RESP_EXOKAY;
end else begin
w_state_q <= w_state_d;
w_req_q <= w_req_d ;
Expand Down