mor1kx-bemicrocv/ip/altera/ddr3/altera_incr_burst_converter.sv

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2016-08-04 19:22:38 +02:00
// (C) 2001-2015 Altera Corporation. All rights reserved.
// Your use of Altera Corporation's design tools, logic functions and other
// software and tools, and its AMPP partner logic functions, and any output
// files any of the foregoing (including device programming or simulation
// files), and any associated documentation or information are expressly subject
// to the terms and conditions of the Altera Program License Subscription
// Agreement, Altera MegaCore Function License Agreement, or other applicable
// license agreement, including, without limitation, that your use is for the
// sole purpose of programming logic devices manufactured by Altera and sold by
// Altera or its authorized distributors. Please refer to the applicable
// agreement for further details.
// $Id: //acds/rel/15.1/ip/merlin/altera_merlin_burst_adapter/new_source/altera_incr_burst_converter.sv#1 $
// $Revision: #1 $
// $Date: 2015/08/09 $
// $Author: swbranch $
// ----------------------------------------------------------
// This component is used for INCR Avalon slave
// (slave which only supports INCR) or AXI slave.
// It converts burst length of input packet
// to match slave burst.
// ----------------------------------------------------------
`timescale 1 ns / 1 ns
module altera_incr_burst_converter
#(
parameter
// ----------------------------------------
// Burst length Parameters
// (real burst length value, not bytecount)
// ----------------------------------------
MAX_IN_LEN = 16,
MAX_OUT_LEN = 4,
NUM_SYMBOLS = 4,
ADDR_WIDTH = 12,
BNDRY_WIDTH = 12,
BURSTSIZE_WIDTH = 3,
IN_NARROW_SIZE = 0,
PURELY_INCR_AVL_SYS = 0,
// ------------------
// Derived Parameters
// ------------------
LEN_WIDTH = log2ceil(MAX_IN_LEN) + 1,
OUT_LEN_WIDTH = log2ceil(MAX_OUT_LEN) + 1,
LOG2_NUMSYMBOLS = log2ceil(NUM_SYMBOLS)
)
(
input clk,
input reset,
input enable,
input is_write,
input [LEN_WIDTH - 1 : 0] in_len,
input in_sop,
input [ADDR_WIDTH - 1 : 0] in_addr,
input [ADDR_WIDTH - 1 : 0] in_addr_reg,
input [BNDRY_WIDTH - 1 : 0] in_burstwrap_reg,
input [BURSTSIZE_WIDTH - 1 : 0] in_size_t,
input [BURSTSIZE_WIDTH - 1 : 0] in_size_reg,
// converted output length
// out_len : compressed burst, read
// uncompressed_len: uncompressed, write
output reg [LEN_WIDTH - 1 : 0] out_len,
output reg [LEN_WIDTH - 1 : 0] uncompr_out_len,
// Compressed address output
output reg [ADDR_WIDTH - 1 : 0] out_addr,
output reg new_burst_export
);
// ----------------------------------------
// Signals for wrapping support
// ----------------------------------------
reg [LEN_WIDTH - 1 : 0] remaining_len;
reg [LEN_WIDTH - 1 : 0] next_out_len;
reg [LEN_WIDTH - 1 : 0] next_rem_len;
reg [LEN_WIDTH - 1 : 0] uncompr_remaining_len;
reg [LEN_WIDTH - 1 : 0] next_uncompr_remaining_len;
reg [LEN_WIDTH - 1 : 0] next_uncompr_rem_len;
reg new_burst;
reg uncompr_sub_burst;
// Avoid QIS warning
wire [OUT_LEN_WIDTH - 1 : 0] max_out_length;
assign max_out_length = MAX_OUT_LEN[OUT_LEN_WIDTH - 1 : 0];
always_comb begin
new_burst_export = new_burst;
end
// -------------------------------------------
// length remaining calculation
// -------------------------------------------
always_comb begin : proc_uncompressed_remaining_len
if ((in_len <= max_out_length) && is_write) begin
uncompr_remaining_len = in_len;
end else begin
uncompr_remaining_len = max_out_length;
end
if (uncompr_sub_burst)
uncompr_remaining_len = next_uncompr_rem_len;
end
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
next_uncompr_rem_len <= 0;
end
else if (enable) begin
next_uncompr_rem_len <= uncompr_remaining_len - 1'b1; // in term of length, it just reduces 1
end
end
always_comb begin : proc_compressed_remaining_len
remaining_len = in_len;
if (!new_burst)
remaining_len = next_rem_len;
end
always_ff@(posedge clk or posedge reset) begin : proc_next_uncompressed_remaining_len
if(reset) begin
next_uncompr_remaining_len <= '0;
end
else if (enable) begin
if (in_sop) begin
next_uncompr_remaining_len <= in_len - max_out_length;
end
else if (!uncompr_sub_burst)
next_uncompr_remaining_len <= next_uncompr_remaining_len - max_out_length;
end
end
always_comb begin
next_out_len = max_out_length;
if (remaining_len < max_out_length) begin
next_out_len = remaining_len;
end
end // always_comb
// --------------------------------------------------
// Length remaining calculation : compressed
// --------------------------------------------------
// length remaining for compressed transaction
// for wrap, need special handling for first out length
always_ff @(posedge clk, posedge reset) begin
if (reset)
next_rem_len <= 0;
else if (enable) begin
if (new_burst)
next_rem_len <= in_len - max_out_length;
else
next_rem_len <= next_rem_len - max_out_length;
end
end
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
uncompr_sub_burst <= 0;
end
else if (enable && is_write) begin
uncompr_sub_burst <= (uncompr_remaining_len > 1'b1);
end
end
// --------------------------------------------------
// Control signals
// --------------------------------------------------
wire end_compressed_sub_burst;
assign end_compressed_sub_burst = (remaining_len == next_out_len);
// new_burst:
// the converter takes in_len for new calculation
always_ff @(posedge clk, posedge reset) begin
if (reset)
new_burst <= 1;
else if (enable)
new_burst <= end_compressed_sub_burst;
end
// --------------------------------------------------
// Output length
// --------------------------------------------------
// register out_len for compressed trans
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
out_len <= 0;
end
else if (enable) begin
out_len <= next_out_len;
end
end
// register uncompr_out_len for uncompressed trans
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
uncompr_out_len <= '0;
end
else if (enable) begin
uncompr_out_len <= uncompr_remaining_len;
end
end
// --------------------------------------------------
// Address Calculation
// --------------------------------------------------
reg [ADDR_WIDTH - 1 : 0] addr_incr_sel;
reg [ADDR_WIDTH - 1 : 0] addr_incr_sel_reg;
reg [ADDR_WIDTH - 1 : 0] addr_incr_full_size;
localparam [ADDR_WIDTH - 1 : 0] ADDR_INCR = MAX_OUT_LEN << LOG2_NUMSYMBOLS;
generate
if (IN_NARROW_SIZE) begin : narrow_addr_incr
reg [ADDR_WIDTH - 1 : 0] addr_incr_variable_size;
reg [ADDR_WIDTH - 1 : 0] addr_incr_variable_size_reg;
assign addr_incr_variable_size = MAX_OUT_LEN << in_size_t;
assign addr_incr_variable_size_reg = MAX_OUT_LEN << in_size_reg;
assign addr_incr_sel = addr_incr_variable_size;
assign addr_incr_sel_reg = addr_incr_variable_size_reg;
end
else begin : full_addr_incr
assign addr_incr_full_size = ADDR_INCR[ADDR_WIDTH - 1 : 0];
assign addr_incr_sel = addr_incr_full_size;
assign addr_incr_sel_reg = addr_incr_full_size;
end
endgenerate
reg [ADDR_WIDTH - 1 : 0] next_out_addr;
reg [ADDR_WIDTH - 1 : 0] incremented_addr;
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
out_addr <= '0;
end else begin
if (enable) begin
out_addr <= (next_out_addr);
end
end
end
generate
if (!PURELY_INCR_AVL_SYS) begin : incremented_addr_normal
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
incremented_addr <= '0;
end
else if (enable) begin
incremented_addr <= (next_out_addr + addr_incr_sel_reg);
if (new_burst) begin
incremented_addr <= (next_out_addr + addr_incr_sel);
end
end
end // always_ff @
always_comb begin
next_out_addr = in_addr;
if (!new_burst) begin
next_out_addr = incremented_addr;
end
end
end
else begin : incremented_addr_pure_av
always_ff @(posedge clk, posedge reset) begin
if (reset) begin
incremented_addr <= '0;
end
else if (enable) begin
incremented_addr <= (next_out_addr + addr_incr_sel_reg);
end
end // always_ff @
always_comb begin
next_out_addr = in_addr;
if (!new_burst) begin
next_out_addr = (incremented_addr);
end
end
end
endgenerate
// --------------------------------------------------
// Calculates the log2ceil of the input value
// --------------------------------------------------
function integer log2ceil;
input integer val;
reg[31:0] i;
begin
i = 1;
log2ceil = 0;
while (i < val) begin
log2ceil = log2ceil + 1;
i = i[30:0] << 1;
end
end
endfunction
endmodule