Skip to content

Commit

Permalink
axi_dw_downsizer: Fix overflow of B forward FIFO
Browse files Browse the repository at this point in the history
  • Loading branch information
@andreaskurth @suehtamacv
andreaskurth authored and suehtamacv committed Oct 27, 2020
1 parent 49a874a commit ada7c9e
Showing 1 changed file with 61 additions and 59 deletions.
120 changes: 61 additions & 59 deletions src/axi_dw_downsizer.sv
View file
Original file line number Diff line number Diff line change
Expand Up @@ -787,78 +787,80 @@ module axi_dw_downsizer #(
w_req_d.aw_throw_error = 1'b0 ;
w_req_d.burst_resp = axi_pkg::RESP_OKAY;

if (slv_req_i.aw_valid && slv_req_i.aw.atop[5]) begin // ATOP with an R response
inject_aw_into_ar_req = 1'b1 ;
slv_resp_o.aw_ready = inject_aw_into_ar_gnt;
end else begin // Regular AW
slv_resp_o.aw_ready = 1'b1;
end
if (!forward_b_beat_full) begin
if (slv_req_i.aw_valid && slv_req_i.aw.atop[5]) begin // ATOP with an R response
inject_aw_into_ar_req = 1'b1 ;
slv_resp_o.aw_ready = inject_aw_into_ar_gnt;
end else begin // Regular AW
slv_resp_o.aw_ready = 1'b1;
end

// New write request
if (slv_req_i.aw_valid && slv_resp_o.aw_ready && !forward_b_beat_full) begin
// Default state
w_state_d = W_PASSTHROUGH;

// Save beat
w_req_d.aw = slv_req_i.aw ;
w_req_d.aw_valid = 1'b1 ;
w_req_d.burst_len = slv_req_i.aw.len ;
w_req_d.orig_aw_len = slv_req_i.aw.len ;
w_req_d.orig_aw_size = slv_req_i.aw.size ;
w_req_d.orig_aw_burst = slv_req_i.aw.burst;

case (slv_req_i.aw.burst)
axi_pkg::BURST_INCR: begin
// Evaluate downsize ratio
automatic addr_t size_mask = (1 << slv_req_i.aw.size) - 1 ;
automatic addr_t conv_ratio = ((1 << slv_req_i.aw.size) + AxiMstPortStrbWidth - 1) / AxiMstPortStrbWidth;

// Evaluate output burst length
automatic addr_t align_adj = (slv_req_i.aw.addr & size_mask & ~MstPortByteMask) / AxiMstPortStrbWidth;
w_req_d.burst_len = (slv_req_i.aw.len + 1) * conv_ratio - align_adj - 1 ;

if (conv_ratio != 1) begin
w_req_d.aw.size = AxiMstPortMaxSize;

if (w_req_d.burst_len <= 255) begin
w_state_d = W_INCR_DOWNSIZE ;
w_req_d.aw.len = w_req_d.burst_len;
end else begin
w_state_d = W_SPLIT_INCR_DOWNSIZE;
w_req_d.aw.len = 255 - align_adj ;
end
end
end
// New write request
if (slv_req_i.aw_valid && slv_resp_o.aw_ready) begin
// Default state
w_state_d = W_PASSTHROUGH;

axi_pkg::BURST_FIXED: begin
// Single transaction
if (slv_req_i.aw.len == '0) begin
// Save beat
w_req_d.aw = slv_req_i.aw ;
w_req_d.aw_valid = 1'b1 ;
w_req_d.burst_len = slv_req_i.aw.len ;
w_req_d.orig_aw_len = slv_req_i.aw.len ;
w_req_d.orig_aw_size = slv_req_i.aw.size ;
w_req_d.orig_aw_burst = slv_req_i.aw.burst;

case (slv_req_i.aw.burst)
axi_pkg::BURST_INCR: begin
// Evaluate downsize ratio
automatic addr_t size_mask = (1 << slv_req_i.aw.size) - 1 ;
automatic addr_t conv_ratio = ((1 << slv_req_i.aw.size) + AxiMstPortStrbWidth - 1) / AxiMstPortStrbWidth;

// Evaluate output burst length
automatic addr_t align_adj = (slv_req_i.aw.addr & size_mask & ~MstPortByteMask) / AxiMstPortStrbWidth;
w_req_d.burst_len = (conv_ratio >= align_adj + 1) ? (conv_ratio - align_adj - 1) : 0;
w_req_d.burst_len = (slv_req_i.aw.len + 1) * conv_ratio - align_adj - 1 ;

if (conv_ratio != 1) begin
w_state_d = W_INCR_DOWNSIZE ;
w_req_d.aw.len = w_req_d.burst_len ;
w_req_d.aw.size = AxiMstPortMaxSize ;
w_req_d.aw.burst = axi_pkg::BURST_INCR;
w_req_d.aw.size = AxiMstPortMaxSize;

if (w_req_d.burst_len <= 255) begin
w_state_d = W_INCR_DOWNSIZE ;
w_req_d.aw.len = w_req_d.burst_len;
end else begin
w_state_d = W_SPLIT_INCR_DOWNSIZE;
w_req_d.aw.len = 255 - align_adj ;
end
end
end else begin
// The downsizer does not support fixed bursts
w_req_d.aw_throw_error = 1'b1;
end
end

axi_pkg::BURST_WRAP: begin
// The DW converter does not support this type of burst.
w_state_d = W_PASSTHROUGH;
w_req_d.aw_throw_error = 1'b1 ;
end
endcase
axi_pkg::BURST_FIXED: begin
// Single transaction
if (slv_req_i.aw.len == '0) begin
// Evaluate downsize ratio
automatic addr_t size_mask = (1 << slv_req_i.aw.size) - 1 ;
automatic addr_t conv_ratio = ((1 << slv_req_i.aw.size) + AxiMstPortStrbWidth - 1) / AxiMstPortStrbWidth;

// Evaluate output burst length
automatic addr_t align_adj = (slv_req_i.aw.addr & size_mask & ~MstPortByteMask) / AxiMstPortStrbWidth;
w_req_d.burst_len = (conv_ratio >= align_adj + 1) ? (conv_ratio - align_adj - 1) : 0;

if (conv_ratio != 1) begin
w_state_d = W_INCR_DOWNSIZE ;
w_req_d.aw.len = w_req_d.burst_len ;
w_req_d.aw.size = AxiMstPortMaxSize ;
w_req_d.aw.burst = axi_pkg::BURST_INCR;
end
end else begin
// The downsizer does not support fixed bursts
w_req_d.aw_throw_error = 1'b1;
end
end

axi_pkg::BURST_WRAP: begin
// The DW converter does not support this type of burst.
w_state_d = W_PASSTHROUGH;
w_req_d.aw_throw_error = 1'b1 ;
end
endcase
end
end
end
end
Expand Down

0 comments on commit ada7c9e

Please sign in to comment.