Subversion Repositories astron_diagnostics

-------------------------------------------------------------------------------

--

-- Copyright 2020

-- ASTRON (Netherlands Institute for Radio Astronomy) <http://www.astron.nl/>

-- P.O.Box 2, 7990 AA Dwingeloo, The Netherlands

-- 

-- Licensed under the Apache License, Version 2.0 (the "License");

-- you may not use this file except in compliance with the License.

-- You may obtain a copy of the License at

-- 

--     http://www.apache.org/licenses/LICENSE-2.0

-- 

-- Unless required by applicable law or agreed to in writing, software

-- distributed under the License is distributed on an "AS IS" BASIS,

-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

-- See the License for the specific language governing permissions and

-- limitations under the License.

--

-------------------------------------------------------------------------------

-- Purpose: Block generator repeating a data pattern

-- Description:

--   The data pattern is read via the buf_* MM interface. The output data

--   block is controlled via ctrl of type t_diag_block_gen with fields:

--

--     enable             : sl  -- block enable immediately

--     enable_sync        : sl  -- block enable at next en_sync pulse

--     samples_per_packet : slv -- number of valid per block, from sop to eop

--     blocks_per_sync    : slv -- number of blocks per sync interval

--     gapsize            : slv -- number of clk cycles between blocks, so

--                                 between last eop and next sop

--     mem_low_adrs       : slv -- block start address at MM interface

--     mem_high_adrs      : slv -- end address at MM interface

--     bsn_init           : slv -- BSN of first output block

--                                          

--   The MM reading starts at mem_low_adrs when the BG is first enabled. If

--   the mem_high_adrs-mem_low_adrs+1 < samples_per_packet then the reading

--   wraps and continues from mem_low_adrs. For every new block the reading

--   continues where it left in the previous block. This MM reading scheme

--   allows using a periodic data pattern that can extends accross blocks and

--   sync intervals, because is continues for as long as the BG remains

--   enabled.

--

--   The input en_sync can be used as trigger to start multiple BG at the same

--   clk cycle. The BG creates a out_sosi.sync at the first sop and the sop of

--   every blocks_per_sync.

--

--   The current block is finished properly after enable gows low, to ensure 

--   that all blocks have the same length. A new ctrl is accepted after a

--   current block has finished, to ensure that no fractional blocks will 

--   enter the stream.

--

--   The BG supports block flow control via out_siso.xon. The BG also supports

--   sample flow control via out_siso.ready.

--

--   The read data is resized and output as unsigned via:

--   . out_sosi.data(g_buf_dat_w-1:0).

--   The read data is also output as complex data via:

--   . out_sosi.im(g_buf_dat_w  -1:g_buf_dat_w/2)

--   . out_sosi.re(g_buf_dat_w/2-1:            0)

library IEEE, common_pkg_lib, dp_pkg_lib;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.NUMERIC_STD.ALL;

use common_pkg_lib.common_pkg.ALL;

use work.diag_pkg.ALL;

use dp_pkg_lib.dp_stream_pkg.ALL;

entity diag_block_gen is

  generic (

    g_blk_sync   : boolean := false;  -- when true use active sync during entire block, else use single clock cycle sync pulse

    g_buf_dat_w  : natural := 32;

    g_buf_addr_w : natural := 7

  );

  port (

    rst          : in  std_logic;

    clk          : in  std_logic;

    buf_addr     : out std_logic_vector(g_buf_addr_w-1 downto 0);

    buf_rden     : out std_logic;

    buf_rddat    : in  std_logic_vector(g_buf_dat_w-1 downto 0);

    buf_rdval    : in  std_logic;

    ctrl         : in  t_diag_block_gen;

    en_sync      : in  std_logic := '1';

    out_siso     : in  t_dp_siso := c_dp_siso_rdy;

    out_sosi     : out t_dp_sosi

  );

end diag_block_gen;

architecture rtl of diag_block_gen is

  type state_type is (s_idle, s_block, s_gap);

  type reg_type is record

    ctrl_reg    : t_diag_block_gen;  -- capture ctrl

    blk_en      : std_logic;  -- enable at block level

    blk_xon     : std_logic;  -- siso.xon at block level, the BG continues but the sosi control depend on xon (the BG does not support siso.ready)

    blk_sync    : std_logic;  -- block sync alternative of the pulse sync

    pls_sync    : std_logic;  -- pulse sync

    valid       : std_logic;

    sop         : std_logic;

    eop         : std_logic;

    rd_ena      : std_logic;

    samples_cnt : natural range 0 to 2**c_diag_bg_samples_per_packet_w-1;

    blocks_cnt  : natural range 0 to 2**c_diag_bg_blocks_per_sync_w-1;

    bsn_cnt     : std_logic_vector(c_diag_bg_bsn_init_w-1 downto 0);  -- = c_dp_stream_bsn_w

    mem_cnt     : natural range 0 to 2**g_buf_addr_w-1;

    state       : state_type;   -- The state machine. 

  end record;

  signal r, rin     : reg_type;

  signal out_sosi_i : t_dp_sosi := c_dp_sosi_rst;  -- Signal used to assign reset values to output

begin

    p_comb : process(r, rst, ctrl, en_sync, out_siso)

      variable v                    : reg_type;

      variable v_samples_per_packet : natural;

      variable v_gapsize            : natural;

      variable v_blocks_per_sync    : natural;

      variable v_mem_low_adrs       : natural;

      variable v_mem_high_adrs      : natural;

    begin

      v_samples_per_packet := TO_UINT(r.ctrl_reg.samples_per_packet);

      v_gapsize            := TO_UINT(r.ctrl_reg.gapsize);

      v_blocks_per_sync    := TO_UINT(r.ctrl_reg.blocks_per_sync);

      v_mem_low_adrs       := TO_UINT(r.ctrl_reg.mem_low_adrs);

      v_mem_high_adrs      := TO_UINT(r.ctrl_reg.mem_high_adrs);

      v                   := r;     -- default hold all r fields

      v.pls_sync          := '0';

      v.valid             := '0';

      v.sop               := '0';

      v.eop               := '0';

      v.rd_ena            := '0';

      -- Control block generator enable

      if ctrl.enable='0' then

        v.blk_en := '0';  -- disable immediately

      elsif ctrl.enable_sync='0' then

        v.blk_en := '1';  -- enable immediately or keep enabled

      elsif en_sync='1' then

        v.blk_en := '1';  -- enable at input sync pulse or keep enabled

      end if;

      -- The pulse sync is high at the sop of the first block, the block sync is high during the entire block until the eop

      if r.eop='1' then

        v.blk_sync := '0';

      end if;

      -- Increment the block sequence number counter after each block

      if r.eop='1' then

        v.bsn_cnt := incr_uvec(r.bsn_cnt, 1);

      end if;

      case r.state is

        when s_idle =>

          v.ctrl_reg    := ctrl;        -- accept new control settings

          v.blk_xon     := out_siso.xon;

          v.blk_sync    := '0';

          v.samples_cnt := 0;

          v.blocks_cnt  := 0;

          v.bsn_cnt     := ctrl.bsn_init;

          v.mem_cnt     := v_mem_low_adrs;

          if r.blk_en = '1' then       -- Wait until enabled

            if out_siso.xon='1' then   -- Wait until XON is 1

              v.rd_ena      := '1';

              v.state       := s_block;

            end if;

          end if;

        when s_block =>

          if out_siso.ready='1' then

            v.rd_ena := '1';  -- read next data

            if r.samples_cnt = 0 and r.blocks_cnt = 0 then

              v.pls_sync    := '1';                      -- Always start with a pulse sync          

              v.blk_sync    := '1';

              v.sop         := '1';

              v.samples_cnt := v.samples_cnt + 1;

            elsif r.samples_cnt = 0 then

              v.sop         := '1';

              v.samples_cnt := v.samples_cnt + 1;

            elsif r.samples_cnt >= v_samples_per_packet-1 and v_gapsize = 0 and r.blocks_cnt >= v_blocks_per_sync-1 then

              v.eop         := '1';

              v.ctrl_reg    := ctrl;      -- accept new control settings at end of block when gapsize=0

              v.samples_cnt := 0;

              v.blocks_cnt  := 0;

            elsif r.samples_cnt >= v_samples_per_packet-1 and v_gapsize = 0 then

              v.eop         := '1';

              v.ctrl_reg    := ctrl;      -- accept new control settings at end of block when gapsize=0

              v.samples_cnt := 0;

              v.blocks_cnt  := r.blocks_cnt + 1;

            elsif r.samples_cnt >= v_samples_per_packet-1 then

              v.eop         := '1';

              v.samples_cnt := 0;

              v.rd_ena      := '0';

              v.state       := s_gap;

            else

              v.samples_cnt := r.samples_cnt + 1;

            end if;

            v.valid  := '1';  -- output pending data

            if r.mem_cnt >= v_mem_high_adrs then

              v.mem_cnt := v_mem_low_adrs;

            else

              v.mem_cnt := r.mem_cnt + 1;

            end if;

            if v.eop = '1' and r.blk_en = '0' then

              v.state := s_idle;          -- accept disable after eop, not during block

            end if;

            if r.eop = '1' then

              v.blk_xon := out_siso.xon;  -- accept XOFF after eop, not during block

            end if;

          end if;  -- out_siso.ready='1'

        when s_gap =>

          if r.samples_cnt >= v_gapsize-1 and r.blocks_cnt >= v_blocks_per_sync-1 then

            v.ctrl_reg    := ctrl;      -- accept new control settings at end of gap

            v.samples_cnt := 0;

            v.blocks_cnt  := 0;

            v.rd_ena      := '1';

            v.state       := s_block;

          elsif r.samples_cnt >= v_gapsize-1 then

            v.ctrl_reg    := ctrl;      -- accept new control settings at end of gap

            v.samples_cnt := 0;

            v.blocks_cnt  := r.blocks_cnt + 1;

            v.rd_ena      := '1';

            v.state       := s_block;

          else

            v.samples_cnt := r.samples_cnt + 1;

          end if;

          if r.blk_en = '0' then

            v.state := s_idle;

          end if;

          v.blk_xon := out_siso.xon;

        when others =>

          v.state := s_idle;

      end case;

      if rst = '1' then

        v.ctrl_reg    := c_diag_block_gen_rst;

        v.blk_en      := '0';

        v.blk_xon     := '0';

        v.blk_sync    := '0';

        v.pls_sync    := '0';

        v.valid       := '0';

        v.sop         := '0';

        v.eop         := '0';

        v.rd_ena      := '0';

        v.samples_cnt := 0;

        v.blocks_cnt  := 0;

        v.bsn_cnt     := (others=>'0');

        v.mem_cnt     := 0;

        v.state       := s_idle;

      end if;

      rin <= v;

    end process;

    p_regs : process(rst, clk)

    begin

      if rising_edge(clk) then

        r <= rin;

      end if;

    end process;

    -- Connect to the outside world

    out_sosi_i.sop   <= r.sop      and r.blk_xon;

    out_sosi_i.eop   <= r.eop      and r.blk_xon;

    out_sosi_i.sync  <= r.pls_sync and r.blk_xon when g_blk_sync=false else r.blk_sync and r.blk_xon;

    out_sosi_i.valid <= r.valid    and r.blk_xon;

    out_sosi_i.bsn   <= r.bsn_cnt;

    out_sosi_i.re    <= RESIZE_DP_DSP_DATA(buf_rddat(g_buf_dat_w/2-1 downto 0));               -- treat as signed

    out_sosi_i.im    <= RESIZE_DP_DSP_DATA(buf_rddat(g_buf_dat_w-1   downto g_buf_dat_w/2));   -- treat as signed

    out_sosi_i.data  <= RESIZE_DP_DATA(    buf_rddat(g_buf_dat_w-1   downto 0));               -- treat as unsigned

    out_sosi <= out_sosi_i;

    buf_addr <= TO_UVEC(r.mem_cnt, g_buf_addr_w);

    buf_rden <= r.rd_ena;

end rtl;