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-- The Potato Processor - A simple processor for FPGAs

-- (c) Kristian Klomsten Skordal 2014 - 2015 <kristian.skordal@wafflemail.net>

-- Report bugs and issues on <http://opencores.org/project,potato,bugtracker>

library ieee;

use ieee.std_logic_1164.all;

use work.pp_types.all;

--! @brief The Potato Processor.

--! This file provides a Wishbone-compatible interface to the Potato processor.

entity pp_potato is

        generic(

                PROCESSOR_ID           : std_logic_vector(31 downto 0) := x"00000000"; --! Processor ID.

                RESET_ADDRESS          : std_logic_vector(31 downto 0) := x"00000200"  --! Address of the first instruction to execute.

        );

        port(

                clk       : in std_logic;

                timer_clk : in std_logic;

                reset     : in std_logic;

                -- Interrupts:

                irq : in std_logic_vector(7 downto 0);

                -- Host/Target interface:

                fromhost_data    : in std_logic_vector(31 downto 0);

                fromhost_updated : in std_logic;

                tohost_data      : out std_logic_vector(31 downto 0);

                tohost_updated   : out std_logic;

                -- Wishbone interface:

                wb_adr_out : out std_logic_vector(31 downto 0);

                wb_sel_out : out std_logic_vector( 3 downto 0);

                wb_cyc_out : out std_logic;

                wb_stb_out : out std_logic;

                wb_we_out  : out std_logic;

                wb_dat_out : out std_logic_vector(31 downto 0);

                wb_dat_in  : in  std_logic_vector(31 downto 0);

                wb_ack_in  : in  std_logic

        );

end entity pp_potato;

architecture behaviour of pp_potato is

        -- Instruction memory signals:

        signal imem_address : std_logic_vector(31 downto 0);

        signal imem_data    : std_logic_vector(31 downto 0);

        signal imem_req, imem_ack : std_logic;

        -- Data memory signals:

        signal dmem_address   : std_logic_vector(31 downto 0);

        signal dmem_data_in   : std_logic_vector(31 downto 0);

        signal dmem_data_out  : std_logic_vector(31 downto 0);

        signal dmem_data_size : std_logic_vector( 1 downto 0);

        signal dmem_read_req  : std_logic;

        signal dmem_read_ack  : std_logic;

        signal dmem_write_req : std_logic;

        signal dmem_write_ack : std_logic;

        -- Wishbone signals:

        signal icache_inputs, dmem_if_inputs   : wishbone_master_inputs;

        signal icache_outputs, dmem_if_outputs : wishbone_master_outputs;

begin

        processor: entity work.pp_core

                generic map(

                        PROCESSOR_ID => PROCESSOR_ID,

                        RESET_ADDRESS => RESET_ADDRESS

                ) port map(

                        clk => clk,

                        reset => reset,

                        timer_clk => timer_clk,

                        imem_address => imem_address,

                        imem_data_in => imem_data,

                        imem_req => imem_req,

                        imem_ack => imem_ack,

                        dmem_address => dmem_address,

                        dmem_data_in => dmem_data_in,

                        dmem_data_out => dmem_data_out,

                        dmem_data_size => dmem_data_size,

                        dmem_read_req => dmem_read_req,

                        dmem_read_ack => dmem_read_ack,

                        dmem_write_req => dmem_write_req,

                        dmem_write_ack => dmem_write_ack,

                        fromhost_data => fromhost_data,

                        fromhost_write_en => fromhost_updated,

                        tohost_data => tohost_data,

                        tohost_write_en => tohost_updated,

                        irq => irq

                );

        icache: entity work.pp_icache

                generic map(

                        LINE_SIZE => 4,

                        NUM_LINES => 128

                ) port map(

                        clk => clk,

                        reset => reset,

                        cache_enable => '1',

                        cache_flush => '0',

                        cached_areas => (others => '1'),

                        mem_address_in => imem_address,

                        mem_data_out => imem_data,

                        mem_data_in => (others => '0'),

                        mem_data_size => b"00",

                        mem_read_req => imem_req,

                        mem_read_ack => imem_ack,

                        mem_write_req => '0',

                        mem_write_ack => open,

                        wb_inputs => icache_inputs,

                        wb_outputs => icache_outputs

                );

        dmem_if: entity work.pp_wb_adapter

                port map(

                        clk => clk,

                        reset => reset,

                        dmem_address => dmem_address,

                        dmem_data_in => dmem_data_out,

                        dmem_data_out => dmem_data_in,

                        dmem_data_size => dmem_data_size,

                        dmem_read_req => dmem_read_req,

                        dmem_read_ack => dmem_read_ack,

                        dmem_write_req => dmem_write_req,

                        dmem_write_ack => dmem_write_ack,

                        wb_inputs => dmem_if_inputs,

                        wb_outputs => dmem_if_outputs

                );

        arbiter: entity work.pp_wb_arbiter

                port map(

                        clk => clk,

                        reset => reset,

                        --m1_inputs => dmem_if_inputs,

                        --m1_outputs => dmem_if_outputs,

                        m1_inputs => icache_inputs,

                        m1_outputs => icache_outputs,

                        m2_inputs => dmem_if_inputs,

                        m2_outputs => dmem_if_outputs,

                        wb_adr_out => wb_adr_out,

                        wb_sel_out => wb_sel_out,

                        wb_cyc_out => wb_cyc_out,

                        wb_stb_out => wb_stb_out,

                        wb_we_out => wb_we_out,

                        wb_dat_out => wb_dat_out,

                        wb_dat_in => wb_dat_in,

                        wb_ack_in => wb_ack_in

                );

end architecture behaviour;