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Reorganize FIFO write logic
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Signed-off-by: Alex Forencich <alex@alexforencich.com>
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@alexforencich
alexforencich committed Aug 15, 2023
1 parent c3cd676 commit 6020d09
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Showing 2 changed files with 116 additions and 104 deletions.
142 changes: 74 additions & 68 deletions rtl/axis_async_fifo.v
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Original file line number Diff line number Diff line change
Expand Up @@ -395,10 +395,80 @@ always @(posedge s_clk) begin
end
end

if (s_axis_tready && s_axis_tvalid) begin
// transfer in
if (!FRAME_FIFO) begin
// normal FIFO mode
if (FRAME_FIFO) begin
// frame FIFO mode
if (s_axis_tready && s_axis_tvalid) begin
// transfer in
if ((full && DROP_WHEN_FULL) || (full_wr && DROP_OVERSIZE_FRAME) || drop_frame_reg) begin
// full, packet overflow, or currently dropping frame
// drop frame
drop_frame_reg <= 1'b1;
if (s_axis_tlast) begin
// end of frame, reset write pointer
wr_ptr_temp = wr_ptr_commit_reg;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
drop_frame_reg <= 1'b0;
overflow_reg <= 1'b1;
end
end else begin
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
wr_ptr_temp = wr_ptr_reg + 1;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
if (s_axis_tlast || (!DROP_OVERSIZE_FRAME && (full_wr || send_frame_reg))) begin
// end of frame or send frame
send_frame_reg <= !s_axis_tlast;
if (s_axis_tlast && DROP_BAD_FRAME && USER_BAD_FRAME_MASK & ~(s_axis_tuser ^ USER_BAD_FRAME_VALUE)) begin
// bad packet, reset write pointer
wr_ptr_temp = wr_ptr_commit_reg;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
bad_frame_reg <= 1'b1;
end else begin
// good packet or packet overflow, update write pointer
wr_ptr_temp = wr_ptr_reg + 1;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_commit_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);

if (wr_ptr_update_reg == wr_ptr_update_ack_sync2_reg) begin
// no sync in progress; sync update
wr_ptr_update_valid_reg <= 1'b0;
wr_ptr_sync_commit_reg <= wr_ptr_temp;
wr_ptr_update_reg <= !wr_ptr_update_ack_sync2_reg;
end else begin
// sync in progress; flag it for later
wr_ptr_update_valid_reg <= 1'b1;
end

good_frame_reg <= s_axis_tlast;
end
end
end
end else if (s_axis_tvalid && full_wr && FRAME_FIFO && !DROP_OVERSIZE_FRAME) begin
// data valid with packet overflow
// update write pointer
send_frame_reg <= 1'b1;
wr_ptr_temp = wr_ptr_reg;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_commit_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);

if (wr_ptr_update_reg == wr_ptr_update_ack_sync2_reg) begin
// no sync in progress; sync update
wr_ptr_update_valid_reg <= 1'b0;
wr_ptr_sync_commit_reg <= wr_ptr_temp;
wr_ptr_update_reg <= !wr_ptr_update_ack_sync2_reg;
end else begin
// sync in progress; flag it for later
wr_ptr_update_valid_reg <= 1'b1;
end
end
end else begin
// normal FIFO mode
if (s_axis_tready && s_axis_tvalid) begin
// transfer in
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
if (drop_frame_reg && LAST_ENABLE) begin
// currently dropping frame
Expand All @@ -414,70 +484,6 @@ always @(posedge s_clk) begin
wr_ptr_commit_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
end
end else if ((full && DROP_WHEN_FULL) || (full_wr && DROP_OVERSIZE_FRAME) || drop_frame_reg) begin
// full, packet overflow, or currently dropping frame
// drop frame
drop_frame_reg <= 1'b1;
if (s_axis_tlast) begin
// end of frame, reset write pointer
wr_ptr_temp = wr_ptr_commit_reg;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
drop_frame_reg <= 1'b0;
overflow_reg <= 1'b1;
end
end else begin
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
wr_ptr_temp = wr_ptr_reg + 1;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
if (s_axis_tlast || (!DROP_OVERSIZE_FRAME && (full_wr || send_frame_reg))) begin
// end of frame or send frame
send_frame_reg <= !s_axis_tlast;
if (s_axis_tlast && DROP_BAD_FRAME && USER_BAD_FRAME_MASK & ~(s_axis_tuser ^ USER_BAD_FRAME_VALUE)) begin
// bad packet, reset write pointer
wr_ptr_temp = wr_ptr_commit_reg;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);
bad_frame_reg <= 1'b1;
end else begin
// good packet or packet overflow, update write pointer
wr_ptr_temp = wr_ptr_reg + 1;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_commit_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);

if (wr_ptr_update_reg == wr_ptr_update_ack_sync2_reg) begin
// no sync in progress; sync update
wr_ptr_update_valid_reg <= 1'b0;
wr_ptr_sync_commit_reg <= wr_ptr_temp;
wr_ptr_update_reg <= !wr_ptr_update_ack_sync2_reg;
end else begin
// sync in progress; flag it for later
wr_ptr_update_valid_reg <= 1'b1;
end

good_frame_reg <= s_axis_tlast;
end
end
end
end else if (s_axis_tvalid && full_wr && FRAME_FIFO && !DROP_OVERSIZE_FRAME) begin
// data valid with packet overflow
// update write pointer
send_frame_reg <= 1'b1;
wr_ptr_temp = wr_ptr_reg;
wr_ptr_reg <= wr_ptr_temp;
wr_ptr_commit_reg <= wr_ptr_temp;
wr_ptr_gray_reg <= bin2gray(wr_ptr_temp);

if (wr_ptr_update_reg == wr_ptr_update_ack_sync2_reg) begin
// no sync in progress; sync update
wr_ptr_update_valid_reg <= 1'b0;
wr_ptr_sync_commit_reg <= wr_ptr_temp;
wr_ptr_update_reg <= !wr_ptr_update_ack_sync2_reg;
end else begin
// sync in progress; flag it for later
wr_ptr_update_valid_reg <= 1'b1;
end
end

Expand Down
78 changes: 42 additions & 36 deletions rtl/axis_fifo.v
View file
Original file line number Diff line number Diff line change
Expand Up @@ -245,46 +245,52 @@ always @(posedge clk) begin
bad_frame_reg <= 1'b0;
good_frame_reg <= 1'b0;

if (s_axis_tready && s_axis_tvalid) begin
// transfer in
if (!FRAME_FIFO) begin
// normal FIFO mode
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
wr_ptr_reg <= wr_ptr_reg + 1;
wr_ptr_commit_reg <= wr_ptr_reg + 1;
end else if ((full && DROP_WHEN_FULL) || (full_wr && DROP_OVERSIZE_FRAME) || drop_frame_reg) begin
// full, packet overflow, or currently dropping frame
// drop frame
drop_frame_reg <= 1'b1;
if (s_axis_tlast) begin
// end of frame, reset write pointer
wr_ptr_reg <= wr_ptr_commit_reg;
drop_frame_reg <= 1'b0;
overflow_reg <= 1'b1;
end
end else begin
// store it
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
wr_ptr_reg <= wr_ptr_reg + 1;
if (s_axis_tlast || (!DROP_OVERSIZE_FRAME && (full_wr || send_frame_reg))) begin
// end of frame or send frame
send_frame_reg <= !s_axis_tlast;
if (s_axis_tlast && DROP_BAD_FRAME && USER_BAD_FRAME_MASK & ~(s_axis_tuser ^ USER_BAD_FRAME_VALUE)) begin
// bad packet, reset write pointer
if (FRAME_FIFO) begin
// frame FIFO mode
if (s_axis_tready && s_axis_tvalid) begin
// transfer in
if ((full && DROP_WHEN_FULL) || (full_wr && DROP_OVERSIZE_FRAME) || drop_frame_reg) begin
// full, packet overflow, or currently dropping frame
// drop frame
drop_frame_reg <= 1'b1;
if (s_axis_tlast) begin
// end of frame, reset write pointer
wr_ptr_reg <= wr_ptr_commit_reg;
bad_frame_reg <= 1'b1;
end else begin
// good packet or packet overflow, update write pointer
wr_ptr_commit_reg <= wr_ptr_reg + 1;
good_frame_reg <= s_axis_tlast;
drop_frame_reg <= 1'b0;
overflow_reg <= 1'b1;
end
end else begin
// store it
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
wr_ptr_reg <= wr_ptr_reg + 1;
if (s_axis_tlast || (!DROP_OVERSIZE_FRAME && (full_wr || send_frame_reg))) begin
// end of frame or send frame
send_frame_reg <= !s_axis_tlast;
if (s_axis_tlast && DROP_BAD_FRAME && USER_BAD_FRAME_MASK & ~(s_axis_tuser ^ USER_BAD_FRAME_VALUE)) begin
// bad packet, reset write pointer
wr_ptr_reg <= wr_ptr_commit_reg;
bad_frame_reg <= 1'b1;
end else begin
// good packet or packet overflow, update write pointer
wr_ptr_commit_reg <= wr_ptr_reg + 1;
good_frame_reg <= s_axis_tlast;
end
end
end
end else if (s_axis_tvalid && full_wr && !DROP_OVERSIZE_FRAME) begin
// data valid with packet overflow
// update write pointer
send_frame_reg <= 1'b1;
wr_ptr_commit_reg <= wr_ptr_reg;
end
end else begin
// normal FIFO mode
if (s_axis_tready && s_axis_tvalid) begin
// transfer in
mem[wr_ptr_reg[ADDR_WIDTH-1:0]] <= s_axis;
wr_ptr_reg <= wr_ptr_reg + 1;
wr_ptr_commit_reg <= wr_ptr_reg + 1;
end
end else if (s_axis_tvalid && full_wr && FRAME_FIFO && !DROP_OVERSIZE_FRAME) begin
// data valid with packet overflow
// update write pointer
send_frame_reg <= 1'b1;
wr_ptr_commit_reg <= wr_ptr_reg;
end

if (rst) begin
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