fpga: rfnoc: fft: Support multiple samples per cycle

This adds the NIPC parameter, which configures support for processing
multiple items or samples per clock cycle. With this enabled, the FFT
block can process at rates higher than 250 MSPS, such as 500 MSPS and
beyond.


Original-commit: fc76aa940e121fe1f85a3513f6d90df4667338cf

lib/rfnoc/blocks/rfnoc_block_fft/fft_depacketize.sv

@@ -227,7 +227,7 @@ module fft_depacketize
 
     symbol_state_t symbol_state = WAIT_SYMBOL_ST;
 
-    logic                  last_symbol;
+    logic                  cp_last_symbol;
     logic                  prefix_rd_stb = 1'b0;
     logic [  CP_LEN_W-1:0] cp_len;
     logic [FFT_SIZE_W-1:0] symbol_size;
@@ -258,7 +258,7 @@ module fft_depacketize
           // wait for their tready signals to be asserted, which on the
           // axi_fifo indicates that they are not full.
           i_symbol_tready <= i_symbol_fifo_tready && i_cp_ins_fifo_tready;
-          last_symbol     <= i_symbol_tdata.last;
+          cp_last_symbol  <= i_symbol_tdata.last;
           cp_len          <= i_cp_ins_tdata;
           if (i_symbol_tvalid && i_symbol_tready) begin
             i_symbol_tready <= 1'b0;
@@ -289,7 +289,7 @@ module fft_depacketize
         prefix_rd_stb        <= 1'b0;
         i_symbol_tready      <= 1'b0;
         i_symbol_fifo_tvalid <= 1'b0;
-        last_symbol          <= 1'bX;
+        cp_last_symbol       <= 1'bX;
         cp_len               <= 'X;
         symbol_size          <= 'X;
       end
@@ -300,9 +300,7 @@ module fft_depacketize
     // Symbol Information FIFO
     //---------------------------------
 
-    logic [15:0] symbol_fifo_space;
-
-    assign i_symbol_fifo_tdata = '{ last_symbol, symbol_size };
+    assign i_symbol_fifo_tdata = '{ cp_last_symbol, symbol_size };
 
     axi_fifo #(
       .WIDTH($bits(symbol_fifo_t)),
@@ -317,7 +315,7 @@ module fft_depacketize
       .o_tdata (o_symbol_fifo_tdata ),
       .o_tvalid(o_symbol_fifo_tvalid),
       .o_tready(o_symbol_fifo_tready),
-      .space   (symbol_fifo_space   ),
+      .space   (                    ),
       .occupied(                    )
     );
 
@@ -428,8 +426,6 @@ module fft_depacketize
   //
   //---------------------------------------------------------------------------
 
-  localparam int BYTES_PER_ITEM = (ITEM_W/8);
-
   typedef enum logic [2:0] {
     WAIT_BURST_ST,
     CALC_ITEMS_ST,