axi: Add AXI RAM module and testbench

Signed-off-by: Alex Forencich <alex@alexforencich.com>

tb/axi/taxi_axi_ram/test_taxi_axi_ram.sv

@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: CERN-OHL-S-2.0
+/*
+
+Copyright (c) 2025 FPGA Ninja, LLC
+
+Authors:
+- Alex Forencich
+
+*/
+
+`resetall
+`timescale 1ns / 1ps
+`default_nettype none
+
+/*
+ * AXI4 RAM testbench
+ */
+module test_taxi_axi_ram #
+(
+    /* verilator lint_off WIDTHTRUNC */
+    parameter DATA_W = 32,
+    parameter ADDR_W = 16,
+    parameter ID_W = 8,
+    parameter PIPELINE_OUTPUT = 0
+    /* verilator lint_on WIDTHTRUNC */
+)
+();
+
+logic clk;
+logic rst;
+
+taxi_axi_if #(
+    .DATA_W(DATA_W),
+    .ADDR_W(ADDR_W+16),
+    .ID_W(ID_W)
+) s_axi(), m_axi();
+
+taxi_axi_ram #(
+    .ADDR_W(ADDR_W),
+    .PIPELINE_OUTPUT(PIPELINE_OUTPUT)
+)
+uut (
+    .clk(clk),
+    .rst(rst),
+
+    /*
+     * AXI4-Lite slave interface
+     */
+    .s_axi_wr(s_axi),
+    .s_axi_rd(s_axi)
+);
+
+endmodule
+
+`resetall