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dp_block_gen_arr.vhd 13.53 KiB
-------------------------------------------------------------------------------
--
-- Copyright (C) 2011
-- ASTRON (Netherlands Institute for Radio Astronomy) <http://www.astron.nl/>
-- P.O.Box 2, 7990 AA Dwingeloo, The Netherlands
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program 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 General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
--
-------------------------------------------------------------------------------
-- Purpose : Generate the sosi control for a block of data based on the
-- input valid
-- Description:
-- All input streams in the snk_in_arr must have the same sosi ctrl and info
-- fields, such that the valid from snk_in_arr(0) is sufficient. Only the
-- data, re, im in the snk_in_arr() differs. Therefore default connect snk_in
-- = snk_in_arr(0).
--
-- When enabled (enable='1') then a block of g_nof_data_per_block words is
-- output via src_out_arr under flow control by the input valid.
--
-- The input sync, sop and eop are ignored. For the output the sync, sop and
-- eop are generated by counting the input valid and using
-- g_nof_data_per_block for the output sop and eop, and using
-- g_nof_blk_per_sync for the output sync.
--
-- The first active input valid starts the dp_block_gen_arr. The first output
-- block will have an output sync and every g_nof_blk_per_sync there is
-- another output sync. Each output block is marked by output sop and output
-- eop. The output sop also marks the output BSN. The output BSN is generated
-- such that it increments for every block and that it restarts at 0 at every
-- output sync.
--
-- Typically the size of g_nof_blk_per_sync*g_nof_data_per_block should match
-- the number of input valids in an input sync interval.
--
-- The local BSN restarts at 0 for every new output sync interval, but instead
-- of BSN = 0 the input BSN will be inserted at the first block in a new
-- output sync interval. If the first output BSN should remain 0 then simply
-- keep snk_in.bsn = 0.
--
-- g_nof_pages_bsn:
-- The input BSN is not available in snk_in_arr(0) if the upstream component
-- does not pass the BSN on. In that case the snk_in.sync and snk_in.bsn can
-- be connected to some further upstream interface that does have the proper
-- BSN. The input BSN is then buffered to align it with the local sync that is
-- recreated for the output. This buffer is set via g_nof_pages_bsn. Typically
-- g_nof_pages_bsn = 1 is sufficient to align the BSN along some DSP,
-- components, because the latency in number of blocks of most DSP functions
-- is much less than a sync interval. For a corner turn that operates per sync
-- interval choosing g_nof_pages_bsn = 2 seems appropriate.
--
-- g_check_input_sync:
-- When g_check_input_sync=FALSE then the input sync is ignored and the first
-- input valid that occurs after when enable is active will start the local
-- sync. When g_check_input_sync=TRUE then the block output for a new sync
-- interval is only started if the input valid also coincides with a input
-- sync. Until then all input valid are ignored and there is no output then.
-- -- Usage:
-- * Example 1: Use snk_in.valid to recreate sync, sop, eop, bsn for a DP
-- function that only passes on the valid.
--
-- - g_check_input_sync = False
-- - g_nof_pages_bsn = 0
--
-- |------|
-- snk_in_arr() ----*--------->| |----> src_out_arr
-- | | dp |
-- (0)| | block|
-- | snk_in | gen |
-- \--------->| arr |
-- |------|
--
-- * Example 2: Use snk_in.valid to recreate sop, eop, bsn and check that the
-- local sync is aligned with the snk_in.sync. If the snk_in.sync
-- does not coincide with the local sync, then stop the output of
-- blocks until the snk_in.sync occurs again.
--
-- - g_check_input_sync = True
-- - g_nof_pages_bsn = 0
--
-- |------|
-- snk_in_arr() ----*--------->| |----> src_out_arr
-- | | dp |
-- (0)| | block|
-- | snk_in | gen |
-- \--------->| arr |
-- |------|
-- * Example 3: Use snk_in.valid to recreate sop, eop, bsn for a DP
-- function that only passes on the valid. However for delay
-- the snk_in.bsn by g_nof_pages_bsn to account for the block
-- latency of the upstream DP components that did not pass on
-- the snk_in.bsn.
--
-- - g_check_input_sync = False
-- - g_nof_pages_bsn >= 1
--
-- |-----| snk_in_arr() |------|
-- -----*-->| |-------*--------->| |----> src_out_arr
-- | | DP | | | dp |
-- | | | (0)| | block|
-- | | | | snk_in | gen |
-- | | | \--*------>| arr |
-- sync| |-----| ^ |------|
-- bsn | |
-- \--------------------/
--
-- Remarks:
-- . No siso flow control, although enable could be used as siso.xon
-- . The channel, empty and err fields are passed on to the output. Typically
-- these fields are not used with DSP data. However this scheme still
-- allows setting these fields to a fixed value via snk_in.
-- . Using g_check_input_sync=True is similar to using a dp_sync_checker in
-- front of this dp_block_gen_arr. However the advantage of dp_sync_checker
-- is that it provides monitoring and control via MM.
LIBRARY IEEE, common_lib;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.NUMERIC_STD.ALL;
USE common_lib.common_pkg.ALL;
USE work.dp_stream_pkg.ALL;
ENTITY dp_block_gen_arr IS
GENERIC (
g_nof_streams : POSITIVE := 1;
g_nof_data_per_block : POSITIVE := 1;
g_nof_blk_per_sync : POSITIVE := 8;
g_check_input_sync : BOOLEAN := FALSE; g_nof_pages_bsn : NATURAL := 0
);
PORT (
rst : IN STD_LOGIC;
clk : IN STD_LOGIC;
-- Streaming sink
snk_in : IN t_dp_sosi; -- = snk_in_arr(0)
snk_in_arr : IN t_dp_sosi_arr(g_nof_streams-1 DOWNTO 0);
-- Streaming source
src_out_arr : OUT t_dp_sosi_arr(g_nof_streams-1 DOWNTO 0);
-- Control
enable : IN STD_LOGIC := '1' -- can connect via MM or could also connect to a src_in.xon
);
END dp_block_gen_arr;
ARCHITECTURE rtl OF dp_block_gen_arr IS
-- Check consistancy of the parameters, the function return value is void, because always true or abort due to failure
FUNCTION parameter_asserts(g_check_input_sync : BOOLEAN; g_nof_pages_bsn : NATURAL) return BOOLEAN IS
BEGIN
IF g_check_input_sync=TRUE THEN
ASSERT g_nof_pages_bsn=0 REPORT "When g_check_input_sync=TRUE then g_nof_pages_bsn must be 0." SEVERITY FAILURE;
-- because snk_in.sync and snk_in.bsn are then already aligned with the first snk_in.valid
END IF;
IF g_nof_pages_bsn>0 THEN
ASSERT g_check_input_sync=FALSE REPORT "When g_nof_pages_bsn>0 then g_check_input_sync must be FALSE." SEVERITY FAILURE;
-- because snk_in.sync and snk_in.bsn are then NOT aligned with the first snk_in.valid
END IF;
RETURN TRUE;
END parameter_asserts;
CONSTANT c_parameters_ok : BOOLEAN := parameter_asserts(g_check_input_sync, g_nof_pages_bsn);
TYPE t_state IS (s_sop, s_data, s_eop);
TYPE t_reg IS RECORD -- local registers
state : t_state;
data_cnt : NATURAL RANGE 0 TO g_nof_data_per_block;
blk_cnt : NATURAL RANGE 0 TO g_nof_blk_per_sync;
src_out : t_dp_sosi;
END RECORD;
CONSTANT c_reg_rst : t_reg := (s_sop, 0, 0, c_dp_sosi_rst);
SIGNAL in_sosi : t_dp_sosi;
SIGNAL in_sync_wr_en : STD_LOGIC_VECTOR(g_nof_pages_bsn-1 DOWNTO 0);
SIGNAL in_bsn_buffer : STD_LOGIC_VECTOR(c_dp_stream_bsn_w-1 DOWNTO 0);
SIGNAL nxt_src_out_arr : t_dp_sosi_arr(g_nof_streams-1 DOWNTO 0);
-- Define the local registers in t_reg record
SIGNAL r : t_reg;
SIGNAL nxt_r : t_reg;
BEGIN
p_clk : PROCESS(rst, clk)
BEGIN
IF rst='1' THEN
r <= c_reg_rst;
src_out_arr <= (OTHERS=>c_dp_sosi_rst);
ELSIF rising_edge(clk) THEN
r <= nxt_r;
src_out_arr <= nxt_src_out_arr;
END IF;
END PROCESS;
no_bsn_buffer : IF g_nof_pages_bsn=0 GENERATE
in_sosi <= snk_in; END GENERATE;
gen_bsn_buffer : IF g_nof_pages_bsn>0 GENERATE
-- Buffer input BSN at each input sync
in_sync_wr_en <= (OTHERS=>snk_in.sync);
u_paged_bsn : ENTITY common_lib.common_paged_reg
GENERIC MAP (
g_data_w => c_dp_stream_bsn_w,
g_nof_pages => g_nof_pages_bsn
)
PORT MAP (
rst => rst,
clk => clk,
wr_en => in_sync_wr_en,
wr_dat => snk_in.bsn,
out_dat => in_bsn_buffer
);
p_snk_in : PROCESS(snk_in, in_bsn_buffer)
BEGIN
in_sosi <= snk_in;
in_sosi.sync <= '0';
in_sosi.bsn <= in_bsn_buffer;
END PROCESS;
END GENERATE;
-- Combine input data with the same out_put info and output ctrl for all streams
nxt_src_out_arr <= func_dp_stream_arr_combine_data_info_ctrl(snk_in_arr, nxt_r.src_out, nxt_r.src_out);
-- Determine the output info and output ctrl using snk_in and r.src_out
p_state : PROCESS(r, enable, in_sosi)
BEGIN
nxt_r <= r;
-- default output in_sosi, hold output bsn and set the output ctrl to '0'
nxt_r.src_out <= in_sosi;
nxt_r.src_out.bsn <= r.src_out.bsn;
nxt_r.src_out.valid <= '0';
nxt_r.src_out.sop <= '0';
nxt_r.src_out.eop <= '0';
nxt_r.src_out.sync <= '0';
CASE r.state IS
WHEN s_sop =>
nxt_r.data_cnt <= 0; -- For clarity init data count to 0 (because it will become 1 anyway at sop)
IF enable='0' THEN -- Check enable in state s_sop to ensure that disable cannot happen during a block
nxt_r.blk_cnt <= 0; -- If disabled then reset block generator and remain in this state
ELSE -- Enabled block generator
IF snk_in.valid='1' THEN -- Once enabled the complete block will be output dependent on the input valid
-- maintain blk_cnt for output sync interval, the blk_cnt is the local bsn that wraps at every sync
IF r.blk_cnt>=g_nof_blk_per_sync-1 THEN
nxt_r.blk_cnt <= 0;
ELSE
nxt_r.blk_cnt <= r.blk_cnt+1;
END IF;
-- create local sync and pass on input bsn at local sync
IF r.blk_cnt=0 THEN -- output sync starts at first input valid
nxt_r.src_out.sync <= '1'; -- output sync for this block
nxt_r.src_out.bsn <= in_sosi.bsn; -- output input bsn at sync
ELSE
nxt_r.src_out.bsn <= TO_DP_BSN(r.blk_cnt); -- output local bsn for the subsequent blocks
END IF;
nxt_r.src_out.valid <= '1';
nxt_r.src_out.sop <= '1';
IF g_nof_data_per_block=1 THEN
nxt_r.src_out.eop <= '1'; -- single word block ELSE
nxt_r.data_cnt <= 1; -- start of multi word block
nxt_r.state <= s_data;
END IF;
-- if enabled then check input sync and stop the new block output if the local sync does not coincide with the input sync
IF g_check_input_sync=TRUE THEN
IF r.blk_cnt=0 THEN
IF snk_in.sync='0' THEN
nxt_r.src_out.valid <= '0'; -- undo all ctrl preparations for the new block
nxt_r.src_out.sop <= '0';
nxt_r.src_out.eop <= '0';
nxt_r.src_out.sync <= '0';
nxt_r.blk_cnt <= 0; -- restart blk_cnt
nxt_r.state <= s_sop; -- remain in this state and wait for snk_in.sync
END IF;
END IF;
END IF;
END IF;
END IF;
WHEN s_data =>
IF snk_in.valid='1' THEN
nxt_r.data_cnt <= r.data_cnt+1;
nxt_r.src_out.valid <= '1';
IF r.data_cnt=g_nof_data_per_block-2 THEN
nxt_r.state <= s_eop;
END IF;
END IF;
WHEN OTHERS => -- s_eop
IF snk_in.valid='1' THEN
nxt_r.src_out.valid <= '1';
nxt_r.src_out.eop <= '1';
nxt_r.state <= s_sop;
END IF;
END CASE;
END PROCESS;
END rtl;