1 files changed, 102 insertions, 0 deletions
diff --git a/platform/wavelet3d/gfx_fifo.sv b/platform/wavelet3d/gfx_fifo.sv
new file mode 100644
index 0000000..7174e4d
--- /dev/null
+++ b/platform/wavelet3d/gfx_fifo.sv
@@ -0,0 +1,102 @@
+module gfx_fifo
+#(int WIDTH = 0,
+  int DEPTH = 0)
+(
+	input  logic        clk,
+	                    rst_n,
+
+	       gfx_beats.rx in,
+	       gfx_beats.tx out
+);
+
+	logic do_read, do_write, full_if_eq, in_stall, out_stall,
+	      may_read, may_write, read, read_ok, write;
+
+	logic[WIDTH - 1:0] fifo[DEPTH], read_data, write_data;
+	logic[$clog2(DEPTH) - 1:0] read_ptr, write_ptr;
+
+	assign do_read = read & may_read;
+	assign do_write = write & may_write;
+
+	always_comb begin
+		may_read = full_if_eq;
+		may_write = !full_if_eq;
+
+		if (read)
+			may_write = 1;
+
+		if (read_ptr != write_ptr) begin
+			may_read = 1;
+			may_write = 1;
+		end
+	end
+
+	gfx_skid_flow in_flow
+	(
+		.clk,
+		.rst_n,
+		.stall(in_stall),
+		.in_ready(in.ready),
+		.in_valid(in.valid),
+		.out_ready(may_write),
+		.out_valid(write)
+	);
+
+	gfx_skid_flow out_flow
+	(
+		.clk,
+		.rst_n,
+		.stall(out_stall),
+		.in_ready(read),
+		.in_valid(read_ok),
+		.out_ready(out.ready),
+		.out_valid(out.valid)
+	);
+
+	gfx_skid_buf #(WIDTH) in_skid
+	(
+		.clk,
+		.in(in.data),
+		.out(write_data),
+		.stall(in_stall)
+	);
+
+	gfx_skid_buf #(WIDTH) out_skid
+	(
+		.clk,
+		.in(read_data),
+		.out(out.data),
+		.stall(out_stall)
+	);
+
+	always_ff @(posedge clk or negedge rst_n)
+		if (~rst_n) begin
+			read_ok <= 0;
+			read_ptr <= 0;
+			write_ptr <= 0;
+			full_if_eq <= 0;
+		end else begin
+			if (~out_stall)
+				read_ok <= read && may_read;
+
+			if (do_read)
+				read_ptr <= read_ptr + 1;
+
+			if (do_write)
+				write_ptr <= write_ptr + 1;
+
+			if (do_read & ~do_write)
+				full_if_eq <= 0;
+			else if (~do_read & do_write)
+				full_if_eq <= 1;
+		end
+
+	always_ff @(posedge clk) begin
+		if (~out_stall)
+			read_data <= fifo[read_ptr];
+
+		if (may_write)
+			fifo[write_ptr] <= write_data;
+	end
+
+endmodule