split out gpmc to wishbone interface to make gpmc top level cleaner

1 files changed, 57 insertions, 0 deletions

diff --git a/usrp2/gpmc/gpmc_wb.v b/usrp2/gpmc/gpmc_wb.v
new file mode 100644
index 000000000..64f6a1c00
--- /dev/null
+++ b/usrp2/gpmc/gpmc_wb.v
@@ -0,0 +1,57 @@
+
+
+module gpmc_wb
+  (input EM_CLK, inout [15:0] EM_D, input [10:1] EM_A, input [1:0] EM_NBE,
+   input EM_NCS, input EM_NWE, input EM_NOE,
+
+   input wb_clk, input wb_rst,
+   output reg [10:0] wb_adr_o, output reg [15:0] wb_dat_mosi, input [15:0] wb_dat_miso,
+   output reg [1:0] wb_sel_o, output wb_cyc_o, output reg wb_stb_o, output reg wb_we_o, input wb_ack_i);
+   
+   // ////////////////////////////////////////////
+   // Control Path, Wishbone bus bridge (wb master)
+   reg [1:0] 	cs_del, we_del, oe_del;
+
+   // Synchronize the async control signals
+   always @(posedge wb_clk)
+     begin
+	cs_del <= { cs_del[0], EM_NCS };
+	we_del <= { we_del[0], EM_NWE };
+	oe_del <= { oe_del[0], EM_NOE };
+     end
+
+   always @(posedge wb_clk)
+     if(cs_del == 2'b10)  // Falling Edge
+       wb_adr_o <= { EM_A, 1'b0 };
+
+   always @(posedge wb_clk)
+     if(we_del == 2'b10)  // Falling Edge
+       begin
+	  wb_dat_mosi <= EM_D;
+	  wb_sel_o <= ~EM_NBE;
+       end
+
+   reg [15:0] EM_D_hold;
+   
+   always @(posedge wb_clk)
+     if(wb_ack_i)
+       EM_D_hold <= wb_dat_miso;
+
+   assign EM_D = wb_ack_i ? wb_dat_miso : EM_D_hold;
+   
+   assign wb_cyc_o = wb_stb_o;
+
+   always @(posedge wb_clk)
+     if(~cs_del[0] & (we_del == 2'b10) )
+       wb_we_o <= 1;
+     else if(wb_ack_i)  // Turn off we when done.  Could also use we_del[0], others...
+       wb_we_o <= 0;
+
+   // FIXME should this look at cs_del[1]?
+   always @(posedge wb_clk)
+     if(~cs_del[0] & ((we_del == 2'b10) | (oe_del == 2'b10)))
+       wb_stb_o <= 1;
+     else if(wb_ack_i)
+       wb_stb_o <= 0;
+   
+endmodule // gpmc_wb