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-- NoCem -- Network on Chip Emulation Tool for System on Chip Research 

-- and Implementations

-- 

-- Copyright (C) 2006  Graham Schelle, Dirk Grunwald

-- 

-- 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 2

-- 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, write to the Free Software

-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  

-- 02110-1301, USA.

-- 

-- The authors can be contacted by email: <schelleg,grunwald>@cs.colorado.edu 

-- 

-- or by mail: Campus Box 430, Department of Computer Science,

-- University of Colorado at Boulder, Boulder, Colorado 80309

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

-- 

-- Filename: vc_node_vc_allocator.vhd

-- 

-- Description: vc_node virtual channel allocator

-- 

--

--VC Allocator will do

--   1. manage vc allocation and deallocation for incoming packets looking for outgoing VC

--

--

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.STD_LOGIC_ARITH.ALL;

use IEEE.STD_LOGIC_UNSIGNED.ALL;

use work.pkg_nocem.all;

entity vc_node_vc_allocator is

    Port (

                local_ch_addr : in std_logic_vector(4 downto 0);

                outoing_vc_status : in std_logic_vector(NOCEM_NUM_VC-1 downto 0);

           n_channel_cntrl_in  : in channel_cntrl_word;

           n_channel_cntrl_out : out channel_cntrl_word;

           s_channel_cntrl_in  : in channel_cntrl_word;

           s_channel_cntrl_out : out channel_cntrl_word;

           e_channel_cntrl_in  : in channel_cntrl_word;

           e_channel_cntrl_out : out channel_cntrl_word;

           w_channel_cntrl_in  : in channel_cntrl_word;

           w_channel_cntrl_out : out channel_cntrl_word;

           ap_channel_cntrl_in  : in channel_cntrl_word;

           ap_channel_cntrl_out : out channel_cntrl_word;

           clk : in std_logic;

      rst : in std_logic

                );

end vc_node_vc_allocator;

architecture Behavioral of vc_node_vc_allocator is

   -- determining if there is a valid request on a per INCOMING channel basis

        signal vc_req_array  : std_logic_vector(4 downto 0);

        -- determine the next free outgoing VC

        signal next_free_vc  : std_logic_vector(NOCEM_NUM_VC-1 downto 0);

        signal vc_state : std_logic_Vector(NOCEM_NUM_VC-1 downto 0);   -- 0: free, 1: allocated --

        signal vc_allocate : std_logic;

        signal free_this_vc      : std_logic_vector(NOCEM_NUM_VC-1 downto 0);

        signal allocated_vc : std_logic_vector(NOCEM_NUM_VC-1 downto 0);

        -- DEBUG SIGNALS

        signal debug_allocated_vc : std_logic_vector(NOCEM_NUM_VC-1 downto 0);

        signal debug_alloc_counter : std_logic_vector(15 downto 0);

        signal debug_dealloc_counter : std_logic_vector(15 downto 0);

begin

        -- setting up incoming request signals

        vc_req_array(NOCEM_NORTH_IX) <= '1' when n_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX) /= 0 and n_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_DEST_CH_HIX downto NOCEM_CHFIFO_VC_REQER_DEST_CH_LIX) = local_ch_addr  else '0';

        vc_req_array(NOCEM_SOUTH_IX) <= '1' when s_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX) /= 0 and s_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_DEST_CH_HIX downto NOCEM_CHFIFO_VC_REQER_DEST_CH_LIX) = local_ch_addr  else '0';

        vc_req_array(NOCEM_WEST_IX) <= '1' when w_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX) /= 0 and w_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_DEST_CH_HIX downto NOCEM_CHFIFO_VC_REQER_DEST_CH_LIX) = local_ch_addr  else '0';

        vc_req_array(NOCEM_EAST_IX) <= '1' when e_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX) /= 0 and e_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_DEST_CH_HIX downto NOCEM_CHFIFO_VC_REQER_DEST_CH_LIX) = local_ch_addr  else '0';

        vc_req_array(NOCEM_AP_IX) <= '1' when ap_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX) /= 0 and ap_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_DEST_CH_HIX downto NOCEM_CHFIFO_VC_REQER_DEST_CH_LIX) = local_ch_addr  else '0';

        -- currently, vc status is '1' when eop is read out of VC

        free_this_vc  <= outoing_vc_status;

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

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

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

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

vc_state_gen_clkd : process (clk,rst)

begin

        if rst='1' then

                vc_state <= (others => '0');

        elsif clk'event and clk='1' then

                -- an interesting bit play that should work to keep vc_state happy....

                vc_state <= (allocated_vc or vc_state) xor free_this_vc;

        end if;

end process;

gen_vc_status_uclkd : process (vc_state)

begin

                next_free_vc <= (others => '0');

                l2: for I in NOCEM_NUM_VC-1 downto 0 loop

                        if vc_state(I) = '0' then

                                next_free_vc <= CONV_STD_LOGIC_VECTOR(2**I,NOCEM_NUM_VC);

                        end if;

                end loop;

end process;

gen_grant_clkd : process (clk,rst)

begin

        if rst='1' then

                n_channel_cntrl_out <= (others => '0');

                e_channel_cntrl_out <= (others => '0');

                s_channel_cntrl_out <= (others => '0');

                w_channel_cntrl_out <= (others => '0');

                ap_channel_cntrl_out <= (others => '0');

                vc_allocate <= '0';

                allocated_vc <= (others => '0');

        elsif clk'event and clk='1' then

                allocated_vc <= (others => '0');

                -- zero them out if nothing is happening

                n_channel_cntrl_out <= (others => '0');

                e_channel_cntrl_out <= (others => '0');

                s_channel_cntrl_out <= (others => '0');

                w_channel_cntrl_out <= (others => '0');

                ap_channel_cntrl_out <= (others => '0');

                vc_allocate <= '0';

                -- go through requests and satisfy one of them per cycle

                if vc_req_array(NOCEM_NORTH_IX) = '1' and vc_allocate = '0' then

                        n_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

                        n_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= n_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

                        if next_free_vc /= 0 then

                                vc_allocate <= '1';

                                allocated_vc <= next_free_vc;

                        end if;

                elsif   vc_req_array(NOCEM_SOUTH_IX) = '1' and vc_allocate = '0' then

                        s_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

                        s_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= s_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

                        if next_free_vc /= 0 then

                                vc_allocate <= '1';

                                allocated_vc <= next_free_vc;

                        end if;

                elsif   vc_req_array(NOCEM_EAST_IX) = '1' and vc_allocate = '0' then

                        e_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

                        e_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= e_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

                        if next_free_vc /= 0 then

                                vc_allocate <= '1';

                                allocated_vc <= next_free_vc;

                        end if;

                elsif   vc_req_array(NOCEM_WEST_IX) = '1' and vc_allocate = '0' then

                        w_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

                        w_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= w_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

                        if next_free_vc /= 0 then

                                vc_allocate <= '1';

                                allocated_vc <= next_free_vc;

                        end if;

                elsif   vc_req_array(NOCEM_AP_IX) = '1' and vc_allocate = '0' then

                        ap_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

                        ap_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= ap_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

                        if next_free_vc /= 0 then

                                vc_allocate <= '1';

                                allocated_vc <= next_free_vc;

                        end if;

                else

                        null;

                end if;

        end if;

end process;

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

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

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

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

--

--gen_vc_status_clkd : process (clk,rst)

--begin

--

--      if rst='1' then

--              --next_free_vc <= ('1',others => '0');  

--              vc_state <= (others => '0');

--              

--      elsif clk'event and clk='1' then

--

--      

--

--

--

----            if vc_state = "11" then

----                    next_free_vc <= (others => '0');

----            end if;

--

--

--               l1: for I in NOCEM_NUM_VC-1 downto 0 loop

--                      if vc_state(I) = '0' and next_free_vc(I) = '1' and vc_allocate = '1' then -- free going to allocated

--                              vc_state(I) <= '1';

--                      elsif vc_state(I) = '1' and free_this_vc(I) = '1' then -- allocated going to free

--                              vc_state(I) <= '0';

--                      end if;          

--               end loop;

--

--      end if;

--end process;

--

----gen_vc_status_cclkd : process (clk,rst)

----begin

----

----    if rst='1' then

----            next_free_vc <= (others => '0');

----    elsif clk'event and clk='1' then

----            l2: for I in NOCEM_NUM_VC-1 downto 0 loop

----                    if vc_state(I) = '0' then

----                            next_free_vc <= CONV_STD_LOGIC_VECTOR(2**I,NOCEM_NUM_VC);

----                    end if;                                                                                         

----

----            end loop;

----    end if;

----

----end process;

--

--

--gen_vc_status_uclkd : process (vc_state)

--begin

--              next_free_vc <= (others => '0');

--

--              l2: for I in NOCEM_NUM_VC-1 downto 0 loop

--                      if vc_state(I) = '0' then

--                              next_free_vc <= CONV_STD_LOGIC_VECTOR(2**I,NOCEM_NUM_VC);

--                      end if;                                                                                         

--

--              end loop;

--end process;

--

--

--

--

--

--

--

--gen_grant_clkd : process (clk,rst)

--begin

--

--      if rst='1' then

--      

--              

--              n_channel_cntrl_out <= (others => '0');

--              e_channel_cntrl_out <= (others => '0');

--              s_channel_cntrl_out <= (others => '0');

--              w_channel_cntrl_out <= (others => '0');

--              ap_channel_cntrl_out <= (others => '0');

--              vc_allocate <= '0';

--

--      debug_allocated_vc <= (others => '0');

--

--

--      elsif clk'event and clk='1' then

--      

--              debug_allocated_vc <= (others => '0');

--              

--              

--              -- zero them out if nothing is happening

--              n_channel_cntrl_out <= (others => '0');

--              e_channel_cntrl_out <= (others => '0');

--              s_channel_cntrl_out <= (others => '0');

--              w_channel_cntrl_out <= (others => '0');

--              ap_channel_cntrl_out <= (others => '0');

--              vc_allocate <= '0';

--

--              -- go through requests and satisfy one of them per cycle

--              if vc_req_array(NOCEM_NORTH_IX) = '1' and vc_allocate = '0' then

--                      n_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

--                      n_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= n_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

--                      if next_free_vc /= 0 then

--                              vc_allocate <= '1';

--                              debug_allocated_vc <= next_free_vc;

--                      end if;

--              elsif   vc_req_array(NOCEM_SOUTH_IX) = '1' and vc_allocate = '0' then

--                      s_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

--                      s_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= s_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

--                      if next_free_vc /= 0 then

--                              vc_allocate <= '1';

--                              debug_allocated_vc <= next_free_vc;

--                      end if;

--              elsif   vc_req_array(NOCEM_EAST_IX) = '1' and vc_allocate = '0' then

--                      e_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

--                      e_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= e_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

--                      if next_free_vc /= 0 then

--                              vc_allocate <= '1';

--                              debug_allocated_vc <= next_free_vc;

--                      end if;

--              elsif   vc_req_array(NOCEM_WEST_IX) = '1' and vc_allocate = '0' then

--                      w_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

--                      w_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= w_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

--                      if next_free_vc /= 0 then

--                              vc_allocate <= '1';

--                              debug_allocated_vc <= next_free_vc;

--                      end if;

--              elsif   vc_req_array(NOCEM_AP_IX) = '1' and vc_allocate = '0' then

--                      ap_channel_cntrl_out(NOCEM_CHFIFO_VC_ALLOC_FROMNODE_HIX downto NOCEM_CHFIFO_VC_ALLOC_FROMNODE_LIX) <= next_free_vc;

--                      ap_channel_cntrl_out(NOCEM_CHFIFO_VC_REQER_FROMNODE_HIX downto NOCEM_CHFIFO_VC_REQER_FROMNODE_LIX) <= ap_channel_cntrl_in(NOCEM_CHFIFO_VC_REQER_VCID_HIX downto NOCEM_CHFIFO_VC_REQER_VCID_LIX);

--                      if next_free_vc /= 0 then

--                              vc_allocate <= '1';

--                              debug_allocated_vc <= next_free_vc;

--                      end if;

--              else

--                      null;

--              end if;

--      end if;

--

--

--

--end process;

--

--      signal debug_alloc_counter : std_logic_vector(15 downto 0);

--      signal debug_dealloc_counter : std_logic_vector(15 downto 0);

debug_proc : process (clk,rst)

begin

        if rst='1' then

                debug_alloc_counter   <= (others => '0');

                debug_dealloc_counter <= (others => '0');

        elsif clk'event and clk='1' then

                if vc_allocate = '1' then

                        debug_alloc_counter   <= debug_alloc_counter+1;

                end if;

                if free_this_vc /= 0 then

                        debug_dealloc_counter <= debug_dealloc_counter+1;

                end if;

        end if;

end process;

end Behavioral;