wr_gtx_phy_kintex7_lp: apply Peter's fixes from the Zynq GTX variant

8d98a58b · Tomasz Wlostowski · Tristan Gingold · 44181219 · 8d98a58b · 8d98a58b
Commit 8d98a58b authored Apr 28, 2023 by Tomasz Wlostowski Committed by Tristan Gingold May 05, 2023
Showing with 84 additions and 46 deletions

gtx_comma_detect_kintex7_lp.vhd ...inx/wr_gtp_phy/kintex7-lp/gtx_comma_detect_kintex7_lp.vhd +61 -39

wr_gtx_phy_kintex7_lp.vhd ...rm/xilinx/wr_gtp_phy/kintex7-lp/wr_gtx_phy_kintex7_lp.vhd +23 -7

No files found.
--- a/platform/xilinx/wr_gtp_phy/kintex7-lp/gtx_comma_detect_kintex7_lp.vhd
+++ b/platform/xilinx/wr_gtp_phy/kintex7-lp/gtx_comma_detect_kintex7_lp.vhd
+-------------------------------------------------------------------------------
+-- Title      : Comma detection for Low Phase noise GTX implermentation
+-- Project    : White Rabbit
+-------------------------------------------------------------------------------
+-- File       : gtx_comma_detect_lp.vhd
+-- Author     : Tomasz Wlostowski
+-- Company    : CERN BE-CO-HT
+-- Created    : 2019-03-29
+-- Last update: 2020-08-04
+-- Platform   : FPGA-generic
+-- Standard   : VHDL'93
+-------------------------------------------------------------------------------
+-- Description: Low Phase noise GTX implementation does not use the serializer
+-- 8B/10B decoder. gtx_comma_detect_lp scans for a valid comma in the
+-- 20 bit received raw data.
+-------------------------------------------------------------------------------
+--
+-- Copyright (c) 2010 CERN
+--
+-- This source file is free software; you can redistribute it   
+-- and/or modify it under the terms of the GNU Lesser General   
+-- Public License as published by the Free Software Foundation; 
+-- either version 2.1 of the License, or (at your option) any   
+-- later version.                                               
+--
+-- This source is distributed in the hope that it will be       
+-- useful, but WITHOUT ANY WARRANTY; without even the implied   
+-- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      
+-- PURPOSE.  See the GNU Lesser General Public License for more 
+-- details.                                                     
+--
+-- You should have received a copy of the GNU Lesser General    
+-- Public License along with this source; if not, download it   
+-- from http://www.gnu.org/licenses/lgpl-2.1.html
+-- 
+--
+-------------------------------------------------------------------------------
+-- Revisions  :
+-- Date        Version  Author    Description
+-- 2019-03-29  0.1      tomasz    Initial release
+-- 2020-08-04  0.2      peterj    Cleaned up and added this header
+-------------------------------------------------------------------------------
+
 library ieee;

 use ieee.std_logic_1164.all;
@@ -12,9 +55,11 @@ entity gtx_comma_detect_kintex7_lp is
    rst_i    : in std_logic;

    rx_data_raw_i : in std_logic_vector(19 downto 0);
+    rx_data_raw_o : out std_logic_vector(19 downto 0);

-    comma_target_pos_i : in std_logic_vector(7 downto 0);
-    comma_current_pos_o : out std_logic_vector(7 downto 0);
+    comma_target_pos_i : in std_logic_vector(4 downto 0);
+    comma_current_pos_o : out std_logic_vector(4 downto 0);
+    comma_pos_valid_o : out std_logic;
    
    link_up_o : out std_logic;
    aligned_o : out std_logic
@@ -29,12 +74,10 @@ architecture rtl of gtx_comma_detect_kintex7_lp is
  constant c_IDLE_LENGTH_UP   : integer := 500;
  constant c_IDLE_LENGTH_LOSS : integer := 1000;

-- fixme
-
  signal rx_data_d0     : std_logic_vector(19 downto 0);
  signal rx_data_merged : std_logic_vector(39 downto 0);

-  signal first_comma : std_logic_vector(7 downto 0);
+  signal first_comma : std_logic_vector(4 downto 0);
  signal cnt         : unsigned(15 downto 0);
  signal state       : t_state;
  signal comma_found : std_logic_vector(19 downto 0);
@@ -69,41 +112,15 @@ architecture rtl of gtx_comma_detect_kintex7_lp is

  constant c_K28_5_PLUS : std_logic_vector(9 downto 0) := "1010000011";

-  signal comma_pos            : std_logic_vector(7 downto 0);
-  signal prev_comma_pos       : std_logic_vector(7 downto 0);
-  signal prev_comma_pos_valid : std_logic;
+  signal comma_pos            : std_logic_vector(4 downto 0);
  signal comma_pos_valid      : std_logic;
  signal link_up : std_logic;
  signal link_aligned : std_logic;
-
  
 begin
-
-
--  gen1 : if g_id = 0 generate
--     chipscope_icon_1 : chipscope_icon_v6
--      port map (
--        CONTROL0 => CONTROL);
-
--     chipscope_ila_1 : chipscope_ila_v6
--      port map (
--        CONTROL => CONTROL,
--        CLK     => clk_rx_i,
--        TRIG0   => TRIG0);
-     
--    trig0 (19 downto 0) <= rx_data_raw_i;
--    trig0 (39 downto 20) <= comma_found;
--    trig0 (40) <= comma_pos_valid;
--    trig0 (41) <= link_up;
--    trig0 (42) <= link_aligned;
--    trig0 (43+15 downto 43) <= std_logic_vector(cnt);
--  end generate gen1;
-
-
  
  process(clk_rx_i)
-    variable lookup : std_logic_vector( 9 downto 0);
-    variable comma_pos_comb : std_logic_vector(7 downto 0);
+    variable comma_pos_comb : std_logic_vector(4 downto 0);
  begin
    if rising_edge(clk_rx_i) then
      if rst_i = '1' then
@@ -124,12 +141,12 @@ begin

        if unsigned(comma_found) /= 0 then
          comma_pos_valid <= '1';
+          comma_pos_valid_o <= '1';
          comma_pos <= comma_pos_comb;
-          comma_current_pos_o(7) <= '1';
-          comma_current_pos_o(6 downto 0) <= comma_pos_comb(6 downto 0);
+          comma_current_pos_o <= comma_pos_comb;
        else
-          comma_current_pos_o(7) <= '0';
          comma_pos_valid <= '0';
+          comma_pos_valid_o <= '0';
        end if;
      end if;
    end if;
@@ -139,11 +156,8 @@ begin
  begin
    if rising_edge(clk_rx_i) then
      if rst_i = '1' then
-        
        state <= SYNC_LOST;
      else
-
-
        case state is
          when SYNC_LOST =>
            link_up <= '0';
@@ -191,6 +205,14 @@ begin
    end if;
  end process;

+  -- generate mux shifted output depending on comma_target_pos_i
+  process(rx_data_merged, comma_target_pos_i)
+    variable comma_pos_int : integer range 0 to 19;
+  begin
+    comma_pos_int := to_integer(unsigned(comma_target_pos_i));
+	rx_data_raw_o(19 downto 0) <= rx_data_merged(comma_pos_int + 19 downto comma_pos_int);
+  end process;
+
  aligned_o <= link_aligned;
  link_up_o <= link_up;
  

--- a/platform/xilinx/wr_gtp_phy/kintex7-lp/wr_gtx_phy_kintex7_lp.vhd
+++ b/platform/xilinx/wr_gtp_phy/kintex7-lp/wr_gtx_phy_kintex7_lp.vhd
@@ -2,7 +2,7 @@
 -- Title      : Deterministic Xilinx GTX LPDC wrapper - kintex-7 top module
 -- Project    : White Rabbit Switch
 -------------------------------------------------------------------------------
-- File       : wr_gtx_phy_family7.vhd
+-- File       : wr_gtx_phy_kindex7_lp.vhd
 -- Author     : Peter Jansweijer, Tomasz Wlostowski
 -- Company    : CERN BE-CO-HT
 -- Created    : 2013-04-08
@@ -113,6 +113,9 @@ entity wr_gtx_phy_kintex7_lp is

    -- RX bitslide indication, indicating the delay of the RX path of the
    -- transceiver (in UIs). Must be valid when ch0_rx_data_o is valid.
+    -- In this "low-phase-drift" implementaion rx alignment is fixed by
+    -- throwing the dice until it is on "comma_target_pos".
+    -- rx_bitslide is not used and set to zero.
    rx_bitslide_o : out std_logic_vector(4 downto 0);

    loopen_i      : in std_logic;
@@ -227,9 +230,9 @@ architecture rtl of wr_gtx_phy_kintex7_lp is
  end function;


-  
-  signal comma_target_pos : std_logic_vector(7 downto 0);
-  signal comma_current_pos : std_logic_vector(7 downto 0);
+  signal comma_target_pos : std_logic_vector(4 downto 0);
+  signal comma_current_pos : std_logic_vector(4 downto 0);
+  signal comma_pos_valid : std_logic;

  signal tx_out_clk_div2 : std_logic;
  signal tx_out_clk_div1 : std_logic;
@@ -627,6 +630,7 @@ begin  -- rtl
      rx_data_raw_i => rx_data_raw,
      comma_target_pos_i => comma_target_pos,
      comma_current_pos_o => comma_current_pos,
+      comma_pos_valid_o => comma_pos_valid,
      link_up_o => link_up,
      aligned_o => link_aligned);

@@ -710,19 +714,31 @@ begin  -- rtl
      synced_o => lpdc_regs_in.STAT_txusrpll_locked
      );

+  U_SyncCurrentCommaPosValid : gc_sync_ffs
+    port map
+    (
+      clk_i    => clk_sys_i,
+      rst_n_i  => rst_sys_n_i,
+      data_i   => comma_pos_valid,
+      synced_o => lpdc_regs_in.STAT_comma_pos_valid
+      );
+
  U_SyncCommaCurrentPos : gc_sync_register
    generic map
    (
-      g_width => 8 )
+      g_width => 5 )
    port map
    (
      clk_i    => clk_sys_i,
      rst_n_a_i  => rst_sys_n_i,
      d_i   => comma_current_pos,
-      q_o => lpdc_regs_in.STAT_comma_current_pos
+      q_o => lpdc_regs_in.STAT_comma_current_pos(4 downto 0)
      );

-  
+  lpdc_regs_in.STAT_comma_current_pos(6 downto 5) <= (others => '0');
+-- for backwards compatibility...
+  lpdc_regs_in.STAT_comma_current_pos(7) <= lpdc_regs_in.STAT_comma_pos_valid;
+
  p_gen_rx_outputs : process(rx_rec_clk, gtx_rst)
  begin
    if(gtx_rst = '1') then