dma: Add DMA interface mux modules

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

src/dma/rtl/taxi_dma_if_mux_wr.sv

@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: CERN-OHL-S-2.0
+/*
+
+Copyright (c) 2019-2025 FPGA Ninja, LLC
+
+Authors:
+- Alex Forencich
+
+*/
+
+`resetall
+`timescale 1ns / 1ps
+`default_nettype none
+
+/*
+ * DMA interface mux (write)
+ */
+module taxi_dma_if_mux_wr #
+(
+    // Number of ports
+    parameter PORTS = 2,
+    // select round robin arbitration
+    parameter logic ARB_ROUND_ROBIN = 1'b0,
+    // LSB priority selection
+    parameter logic ARB_LSB_HIGH_PRIO = 1'b1
+)
+(
+    input  wire logic         clk,
+    input  wire logic         rst,
+
+    /*
+     * DMA descriptors from clients
+     */
+    taxi_dma_desc_if.req_snk  client_req[PORTS],
+    taxi_dma_desc_if.sts_src  client_sts[PORTS],
+
+    /*
+     * DMA descriptors to DMA engine
+     */
+    taxi_dma_desc_if.req_src  dma_req,
+    taxi_dma_desc_if.sts_snk  dma_sts,
+
+    /*
+     * RAM interface (from DMA interface)
+     */
+    taxi_dma_ram_if.rd_slv    dma_ram_rd,
+
+    /*
+     * RAM interface (towards client RAMs)
+     */
+    taxi_dma_ram_if.rd_mst    client_ram_rd[PORTS]
+);
+
+// check configuration
+if (dma_ram_rd.SEL_W != dma_req.SRC_SEL_W)
+    $error("Error: Select signal width mismatch (instance %m)");
+
+if (!dma_req.SRC_SEL_EN)
+    $error("Error: Select signal must be enabled (instance %m)");
+
+taxi_dma_desc_mux #(
+    .PORTS(PORTS),
+    .EXTEND_SEL(1),
+    .ARB_ROUND_ROBIN(ARB_ROUND_ROBIN),
+    .ARB_LSB_HIGH_PRIO(ARB_LSB_HIGH_PRIO)
+)
+desc_mux_inst (
+    .clk(clk),
+    .rst(rst),
+
+    /*
+     * DMA descriptors from clients
+     */
+    .client_req(client_req),
+    .client_sts(client_sts),
+
+    /*
+     * DMA descriptors to DMA engines
+     */
+    .dma_req(dma_req),
+    .dma_sts(dma_sts)
+);
+
+taxi_dma_ram_demux_rd #(
+    .PORTS(PORTS)
+)
+ram_demux_inst (
+    .clk(clk),
+    .rst(rst),
+
+    /*
+     * RAM interface (from DMA client/interface)
+     */
+    .dma_ram_rd(dma_ram_rd),
+
+    /*
+     * RAM interface (towards RAM)
+     */
+    .ram_rd(client_ram_rd)
+);
+
+endmodule
+
+`resetall