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- // (C) 2001-2018 Intel Corporation. All rights reserved.
- // Your use of Intel Corporation's design tools, logic functions and other
- // software and tools, and its AMPP partner logic functions, and any output
- // files from 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 Intel Program License Subscription
- // Agreement, Intel FPGA IP License Agreement, or other applicable
- // license agreement, including, without limitation, that your use is for the
- // sole purpose of programming logic devices manufactured by Intel and sold by
- // Intel or its authorized distributors. Please refer to the applicable
- // agreement for further details.
- // (C) 2001-2012 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/18.1std/ip/merlin/altera_merlin_slave_agent/altera_merlin_burst_uncompressor.sv#1 $
- // $Revision: #1 $
- // $Date: 2018/07/18 $
- // $Author: psgswbuild $
- // ------------------------------------------
- // Merlin Burst Uncompressor
- //
- // Compressed read bursts -> uncompressed
- // ------------------------------------------
- `timescale 1 ns / 1 ns
- module altera_merlin_burst_uncompressor
- #(
- parameter ADDR_W = 16,
- parameter BURSTWRAP_W = 3,
- parameter BYTE_CNT_W = 4,
- parameter PKT_SYMBOLS = 4,
- parameter BURST_SIZE_W = 3
- )
- (
- input clk,
- input reset,
-
- // sink ST signals
- input sink_startofpacket,
- input sink_endofpacket,
- input sink_valid,
- output sink_ready,
-
- // sink ST "data"
- input [ADDR_W - 1: 0] sink_addr,
- input [BURSTWRAP_W - 1 : 0] sink_burstwrap,
- input [BYTE_CNT_W - 1 : 0] sink_byte_cnt,
- input sink_is_compressed,
- input [BURST_SIZE_W-1 : 0] sink_burstsize,
-
- // source ST signals
- output source_startofpacket,
- output source_endofpacket,
- output source_valid,
- input source_ready,
-
- // source ST "data"
- output [ADDR_W - 1: 0] source_addr,
- output [BURSTWRAP_W - 1 : 0] source_burstwrap,
- output [BYTE_CNT_W - 1 : 0] source_byte_cnt,
-
- // Note: in the slave agent, the output should always be uncompressed. In
- // other applications, it may be required to leave-compressed or not. How to
- // control? Seems like a simple mux - pass-through if no uncompression is
- // required.
- output source_is_compressed,
- output [BURST_SIZE_W-1 : 0] source_burstsize
- );
- //----------------------------------------------------
- // AXSIZE decoding
- //
- // Turns the axsize value into the actual number of bytes
- // being transferred.
- // ---------------------------------------------------
- function reg[63:0] bytes_in_transfer;
- input [BURST_SIZE_W-1:0] axsize;
- case (axsize)
- 4'b0000: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000000001;
- 4'b0001: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000000010;
- 4'b0010: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000000100;
- 4'b0011: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000001000;
- 4'b0100: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000010000;
- 4'b0101: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000100000;
- 4'b0110: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000001000000;
- 4'b0111: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000010000000;
- 4'b1000: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000100000000;
- 4'b1001: bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000001000000000;
- default:bytes_in_transfer = 64'b0000000000000000000000000000000000000000000000000000000000000001;
- endcase
- endfunction
- // num_symbols is PKT_SYMBOLS, appropriately sized.
- wire [31:0] int_num_symbols = PKT_SYMBOLS;
- wire [BYTE_CNT_W-1:0] num_symbols = int_num_symbols[BYTE_CNT_W-1:0];
-
- // def: Burst Compression. In a merlin network, a compressed burst is one
- // which is transmitted in a single beat. Example: read burst. In
- // constrast, an uncompressed burst (example: write burst) is transmitted in
- // one beat per writedata item.
- //
- // For compressed bursts which require response packets, burst
- // uncompression is required. Concrete example: a read burst of size 8
- // occupies one response-fifo position. When that fifo position reaches the
- // front of the FIFO, the slave starts providing the required 8 readdatavalid
- // pulses. The 8 return response beats must be provided in a single packet,
- // with incrementing address and decrementing byte_cnt fields. Upon receipt
- // of the final readdata item of the burst, the response FIFO item is
- // retired.
- // Burst uncompression logic provides:
- // a) 2-state FSM (idle, busy)
- // reset to idle state
- // transition to busy state for 2nd and subsequent rdv pulses
- // - a single-cycle burst (aka non-burst read) causes no transition to
- // busy state.
- // b) response startofpacket/endofpacket logic. The response FIFO item
- // will have sop asserted, and may have eop asserted. (In the case of
- // multiple read bursts transmit in the command fabric in a single packet,
- // the eop assertion will come in a later FIFO item.) To support packet
- // conservation, and emit a well-formed packet on the response fabric,
- // i) response fabric startofpacket is asserted only for the first resp.
- // beat;
- // ii) response fabric endofpacket is asserted only for the last resp.
- // beat.
- // c) response address field. The response address field contains an
- // incrementing sequence, such that each readdata item is associated with
- // its slave-map location. N.b. a) computing the address correctly requires
- // knowledge of burstwrap behavior b) there may be no clients of the address
- // field, which makes this field a good target for optimization. See
- // burst_uncompress_address_counter below.
- // d) response byte_cnt field. The response byte_cnt field contains a
- // decrementing sequence, such that each beat of the response contains the
- // count of bytes to follow. In the case of sub-bursts in a single packet,
- // the byte_cnt field may decrement down to num_symbols, then back up to
- // some value, multiple times in the packet.
-
- reg burst_uncompress_busy;
- reg [BYTE_CNT_W:0] burst_uncompress_byte_counter;
- wire [BYTE_CNT_W-1:0] burst_uncompress_byte_counter_lint;
- wire first_packet_beat;
- wire last_packet_beat;
- assign first_packet_beat = sink_valid & ~burst_uncompress_busy;
- assign burst_uncompress_byte_counter_lint = burst_uncompress_byte_counter[BYTE_CNT_W-1:0];
- // First cycle: burst_uncompress_byte_counter isn't ready yet, mux the input to
- // the output.
- assign source_byte_cnt =
- first_packet_beat ? sink_byte_cnt : burst_uncompress_byte_counter_lint;
- assign source_valid = sink_valid;
-
- // Last packet beat is set throughout receipt of an uncompressed read burst
- // from the response FIFO - this forces all the burst uncompression machinery
- // idle.
- assign last_packet_beat = ~sink_is_compressed |
- (
- burst_uncompress_busy ?
- (sink_valid & (burst_uncompress_byte_counter_lint == num_symbols)) :
- sink_valid & (sink_byte_cnt == num_symbols)
- );
-
- always @(posedge clk or posedge reset) begin
- if (reset) begin
- burst_uncompress_busy <= '0;
- burst_uncompress_byte_counter <= '0;
- end
- else begin
- if (source_valid & source_ready & sink_valid) begin
- // No matter what the current state, last_packet_beat leads to
- // idle.
- if (last_packet_beat) begin
- burst_uncompress_busy <= '0;
- burst_uncompress_byte_counter <= '0;
- end
- else begin
- if (burst_uncompress_busy) begin
- burst_uncompress_byte_counter <= (burst_uncompress_byte_counter > 0) ?
- (burst_uncompress_byte_counter_lint - num_symbols) :
- (sink_byte_cnt - num_symbols);
- end
- else begin // not busy, at least one more beat to go
- burst_uncompress_byte_counter <= sink_byte_cnt - num_symbols;
- // To do: should busy go true for numsymbols-size compressed
- // bursts?
- burst_uncompress_busy <= 1'b1;
- end
- end
- end
- end
- end
-
- reg [ADDR_W - 1 : 0 ] burst_uncompress_address_base;
- reg [ADDR_W - 1 : 0] burst_uncompress_address_offset;
- wire [63:0] decoded_burstsize_wire;
- wire [ADDR_W-1:0] decoded_burstsize;
- localparam ADD_BURSTWRAP_W = (ADDR_W > BURSTWRAP_W) ? ADDR_W : BURSTWRAP_W;
- wire [ADD_BURSTWRAP_W-1:0] addr_width_burstwrap;
- // The input burstwrap value can be used as a mask against address values,
- // but with one caveat: the address width may be (probably is) wider than
- // the burstwrap width. The spec says: extend the msb of the burstwrap
- // value out over the entire address width (but only if the address width
- // actually is wider than the burstwrap width; otherwise it's a 0-width or
- // negative range and concatenation multiplier).
- generate
- if (ADDR_W > BURSTWRAP_W) begin : addr_sign_extend
- // Sign-extend, just wires:
- assign addr_width_burstwrap[ADDR_W - 1 : BURSTWRAP_W] =
- {(ADDR_W - BURSTWRAP_W) {sink_burstwrap[BURSTWRAP_W - 1]}};
- assign addr_width_burstwrap[BURSTWRAP_W-1:0] = sink_burstwrap [BURSTWRAP_W-1:0];
- end
- else begin
- assign addr_width_burstwrap[BURSTWRAP_W-1 : 0] = sink_burstwrap;
- end
- endgenerate
- always @(posedge clk or posedge reset) begin
- if (reset) begin
- burst_uncompress_address_base <= '0;
- end
- else if (first_packet_beat & source_ready) begin
- burst_uncompress_address_base <= sink_addr & ~addr_width_burstwrap[ADDR_W-1:0];
- end
- end
- assign decoded_burstsize_wire = bytes_in_transfer(sink_burstsize); //expand it to 64 bits
- assign decoded_burstsize = decoded_burstsize_wire[ADDR_W-1:0]; //then take the width that is needed
- wire [ADDR_W : 0] p1_burst_uncompress_address_offset =
- (
- (first_packet_beat ?
- sink_addr :
- burst_uncompress_address_offset) + decoded_burstsize
- ) &
- addr_width_burstwrap[ADDR_W-1:0];
- wire [ADDR_W-1:0] p1_burst_uncompress_address_offset_lint = p1_burst_uncompress_address_offset [ADDR_W-1:0];
- always @(posedge clk or posedge reset) begin
- if (reset) begin
- burst_uncompress_address_offset <= '0;
- end
- else begin
- if (source_ready & source_valid) begin
- burst_uncompress_address_offset <= p1_burst_uncompress_address_offset_lint;
- // if (first_packet_beat) begin
- // burst_uncompress_address_offset <=
- // (sink_addr + num_symbols) & addr_width_burstwrap;
- // end
- // else begin
- // burst_uncompress_address_offset <=
- // (burst_uncompress_address_offset + num_symbols) & addr_width_burstwrap;
- // end
- end
- end
- end
-
- // On the first packet beat, send the input address out unchanged,
- // while values are computed/registered for 2nd and subsequent beats.
- assign source_addr = first_packet_beat ? sink_addr :
- burst_uncompress_address_base | burst_uncompress_address_offset;
- assign source_burstwrap = sink_burstwrap;
- assign source_burstsize = sink_burstsize;
-
- //-------------------------------------------------------------------
- // A single (compressed) read burst will have sop/eop in the same beat.
- // A sequence of read sub-bursts emitted by a burst adapter in response to a
- // single read burst will have sop on the first sub-burst, eop on the last.
- // Assert eop only upon (sink_endofpacket & last_packet_beat) to preserve
- // packet conservation.
- assign source_startofpacket = sink_startofpacket & ~burst_uncompress_busy;
- assign source_endofpacket = sink_endofpacket & last_packet_beat;
- assign sink_ready = source_valid & source_ready & last_packet_beat;
-
- // This is correct for the slave agent usage, but won't always be true in the
- // width adapter. To do: add an "please uncompress" input, and use it to
- // pass-through or modify, and set source_is_compressed accordingly.
- assign source_is_compressed = 1'b0;
- endmodule
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