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White Rabbit core collection
Commit c1ef3f11 authored by Maciej Lipinski's avatar Maciej Lipinski Committed by Grzegorz Daniluk
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[streamers/review] added comments

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modules/wr_streamers/xwr_transmission.vhd
View file @ c1ef3f11
......@@ -12,8 +12,18 @@
-------------------------------------------------------------------------------
-- Description:
--
-- This module is a top-level entity for WR streamers to be used conveniently
-- in application. It is inlcluded in the board top entity of wr-cores as one
-- of transportation means.
--
-- It allows to send and receive streames of data over Ethernet network. In
-- other words, it provides communication over Ethernet network that looks as
-- FIFO: one one node (e.g. SPEC, the user writes to tx streamer words of
-- configureable size. These words are received by the rx streamer in another
-- node (e.g. SVEC) in the same order.
--
-- This module wraps WR_Streamers-related stuff: i.e.
-- 1) IP core modules provided in wr-cores: xtx_streamer, xrx_streamer,
-- 1) IP core modules provided in wr-cores: xtx_streamer, xrx_streamer,
-- xrtx_streamers_stats
-- 2) wishbone registers that provide access to the statistics and streamer's
-- control/status registers.
......@@ -177,22 +187,13 @@ architecture rtl of xwr_transmission is
signal rx_lost_blocks : std_logic;
signal rx_frame : std_logic;
-- signal tx_cfg_mac_local : std_logic_vector(47 downto 0);
-- signal tx_cfg_mac_target : std_logic_vector(47 downto 0);
-- signal tx_cfg_ethertype : std_logic_vector(15 downto 0);
-- signal rx_cfg_mac_local : std_logic_vector(47 downto 0);
-- signal rx_cfg_mac_remote : std_logic_vector(47 downto 0);
-- signal rx_cfg_ethertype : std_logic_vector(15 downto 0);
-- signal rx_cfg_accept_broadcasts: std_logic;
-- signal rx_cfg_filter_remote : std_logic;
-- signal rx_cfg_fixed_latency : std_logic_vector(27 downto 0);
signal tx_streamer_cfg : t_tx_streamer_cfg;
signal rx_streamer_cfg : t_rx_streamer_cfg;
begin
-------------------------------------------------------------------------------------------
-- transmission
-- Instantiate transmission streamer, if configured to do so
-------------------------------------------------------------------------------------------
gen_tx: if(g_streamers_op_mode=TX_ONLY OR g_streamers_op_mode=TX_AND_RX) generate
U_TX: xtx_streamer
......@@ -229,7 +230,7 @@ begin
end generate gen_not_tx;
-------------------------------------------------------------------------------------------
-- reception
-- -- Instantiate reception streamer, if configured to do so
-------------------------------------------------------------------------------------------
gen_rx: if(g_streamers_op_mode=RX_ONLY OR g_streamers_op_mode=TX_AND_RX) generate
U_RX: xrx_streamer
......@@ -270,9 +271,8 @@ begin
end generate gen_not_rx;
-------------------------------------------------------------------------------------------
-- statistics for both
-- Instantiate statistics module - it calculates statistics of rx/tx frames
-------------------------------------------------------------------------------------------
-- statistics are useful only for
U_STATS: xrtx_streamers_stats
generic map(
g_streamers_op_mode => g_streamers_op_mode,
......@@ -317,6 +317,9 @@ begin
rx_data_o <= rx_data;
rx_valid_o <= rx_valid;
-------------------------------------------------------------------------------------------
-- Wishbone access to statistics and configuration
-------------------------------------------------------------------------------------------
U_WB_ADAPTER : wb_slave_adapter
generic map (
g_master_use_struct => true,
......@@ -350,8 +353,16 @@ begin
regs_o => from_wb
);
-------------------------------------------------------------------------------------------
-- Provide generic debugging through WB - user can read 32 bits from each send or received
-- word. It is possible to configure through WB which 32-bits of each word should be
-- "snooped". In particular, user can sent:
-- * whether he/she wishes to look at received or sent words
-- * the byte number at which the snooping shall start, i.e. say users sets byte=2, it means
-- that he will be able to read through wishbone bytes 3-6 of each word, provided the
-- word is of sufficient width
-------------------------------------------------------------------------------------------
start_bit <= from_wb.dbg_ctrl_start_byte_o & "000";
p_debug_mux: process(clk_sys_i)
begin
if rising_edge(clk_sys_i) then
......@@ -376,6 +387,21 @@ begin
to_wb.dbg_data_i <= dbg_word;
to_wb.dummy_dummy_i <= x"DEADBEEF";
-------------------------------------------------------------------------------------------
-- set configuration: the user can access configuration through two channels:
-- 1) records (tx_streamer_cfg & rx_streamer_cfg) with input signals
-- 2) wishbone write
-- By default, the input signals are used. A user can overwrite this default
-- configuration using WB access. To override the default configuration two
-- values needs to be written:
-- 1) the value of a proper configuration, e.g.: tx_cfg0_ethertype, rx_cfg0_filter_remote
-- 2) bit that enables overriding of the configuration, e.g. cfg_or_tx_ethtype and
-- cfg_or_rx_ftr_remote_o respectively
-- The latter (overriding bit) is the so that user can first configure all values
-- that he wishes to and then enable all his desired configuration at the same instant.
-- Otherwise, during the transition (e.g. between writing lsb and msb of MAC), the
-- behaviour could be unpredictable.
-------------------------------------------------------------------------------------------
-- tx config
tx_streamer_cfg.ethertype <= from_wb.tx_cfg0_ethertype_o when (from_wb.cfg_or_tx_ethtype_o='1') else
tx_streamer_cfg_i.ethertype;
......
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