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Commit 5d61e6fb authored by Andrey Filippov's avatar Andrey Filippov
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implemented 4-channel data transfer to the system memory over a single s_axi

parent f685f103
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axi/cmprs_afi_mux.v
View file @ 5d61e6fb
......@@ -49,7 +49,7 @@ module cmprs_afi_mux#(
output fifo_ren0,
input [63:0] fifo_rdata0,
// input fifo_eof0, // single rclk pulse signalling EOF
output eof_written0, // confirm frame written ofer AFI to the system memory (single rclk pulse)
output eof_written0, // confirm frame written over AFI to the system memory (single hclk pulse)
input fifo_flush0, // EOF, need to output all what is in FIFO (Stays active until enough data chunks are read)
input [7:0] fifo_count0, // number of 32-byte chunks in FIFO
......@@ -58,7 +58,7 @@ module cmprs_afi_mux#(
output fifo_ren1,
input [63:0] fifo_rdata1,
// input fifo_eof1, // single rclk pulse signalling EOF
output eof_written1, // confirm frame written ofer AFI to the system memory (single rclk pulse)
output eof_written1, // confirm frame written over AFI to the system memory (single hclk pulse)
input fifo_flush1, // EOF, need to output all what is in FIFO (Stays active until enough data chunks are read)
input [7:0] fifo_count1, // number of 32-byte chunks in FIFO
......@@ -67,7 +67,7 @@ module cmprs_afi_mux#(
output fifo_ren2,
input [63:0] fifo_rdata2,
// input fifo_eof2, // single rclk pulse signalling EOF
output eof_written2, // confirm frame written ofer AFI to the system memory (single rclk pulse)
output eof_written2, // confirm frame written over AFI to the system memory (single hclk pulse)
input fifo_flush2, // EOF, need to output all what is in FIFO (Stays active until enough data chunks are read)
input [7:0] fifo_count2, // number of 32-byte chunks in FIFO
......@@ -76,7 +76,7 @@ module cmprs_afi_mux#(
output fifo_ren3,
input [63:0] fifo_rdata3,
// input fifo_eof3, // single rclk pulse signalling EOF
output eof_written3, // confirm frame written ofer AFI to the system memory (single rclk pulse)
output eof_written3, // confirm frame written over AFI to the system memory (single hclk pulse)
input fifo_flush3, // EOF, need to output all what is in FIFO (Stays active until enough data chunks are read)
input [7:0] fifo_count3, // number of 32-byte chunks in FIFO
......
axi/cmprs_afi_mux_ptr.v
View file @ 5d61e6fb
......@@ -28,10 +28,10 @@ module cmprs_afi_mux_ptr(
input [ 2:0] sa_len_wa, // channel address to write sa/lengths
input sa_len_we, // write enable sa/length data
input en, // 0 - resets, 0->1 resets all pointers. While rezset allows write response
input en, // 0 - resets, 0->1 resets all pointers. While reset allows write response
input [ 3:0] reset_pointers, // per-channel - reset pointers
input pre_busy_w, // combinatorial signal - one before busy[0] (depends on ptr_resetting)
input [ 1:0] winner_channel, // channel that won arbitration for AXI axxess, valid @ pre_busy_w
input [ 1:0] winner_channel, // channel that won arbitration for AXI access, valid @ pre_busy_w
input need_to_bother, // whants to start access if address and data FIFO permit
input [2:0] chunk_inc, // how much to increment chunk pointer (1..4) - valid witrh busy[0]
......
axi/cmprs_afi_mux_ptr_wresp.v
View file @ 5d61e6fb
......@@ -28,7 +28,7 @@ module cmprs_afi_mux_ptr_wresp(
input [ 1:0] length_wa, // channel address to write lengths
input length_we, // write enable length data
input en, // 0 - resets, 0->1 resets all pointers. While rezset allows write response
input en, // 0 - resets, 0->1 resets all pointers. While reset allows write response
input [ 3:0] reset_pointers, // per-channel - reset pointers
input [ 2:0] chunk_ptr_ra, // chunk pointer read address {eof, chn[1:0]}
......
axi/histogram_saxi.v
View file @ 5d61e6fb
......@@ -31,7 +31,7 @@ module histogram_saxi#(
parameter HIST_SAXI_EN = 0,
parameter HIST_SAXI_NRESET = 1,
parameter HIST_CONFIRM_WRITE = 2, // wait write confirmation for each block
parameter HIST_SAXI_AWCACHE = 4, //..7 cache mode (4 bits, default 4'h3)
parameter HIST_SAXI_AWCACHE = 4'h3, //..7 cache mode (4 bits, default 4'h3)
parameter HIST_SAXI_MODE_ADDR_MASK = 'h3ff,
// parameter HIST_SAXI_STATUS_REG = 'h34,
......@@ -237,10 +237,10 @@ module histogram_saxi#(
assign saxi_wstrb = 4'hf; // All bytes
// TODO: MAybe reduce pause between 16-burst pages? Allow some overlap?
// TODO: Maybe reduce pause between 16-burst pages? Allow some overlap?
assign buf_re_w = en_aclk && (|pages_in_buf_rd) && !fifo_half_full && !(&page_ra) && page_read_run; // will stay off until next page
assign fifo_re= saxi_wvalid && saxi_wready;
// currently waiting for SAXI to get confirmnation of all data in the current page before proceeding to teh next
// currently waiting for SAXI to get confirmnation of all data in the current page before proceeding to the next
//
// assign confirm_write
assign block_end = !(|block_start_r) && (confirm_write? (!(|num_bursts_pending)):(!(|num_bursts_in_buf)));
......@@ -390,7 +390,7 @@ module histogram_saxi#(
.stb (cmd_stb), // input
.addr (cmd_wa), // output[3:0]
.data (cmd_data), // output[31:0]
.we ({we_addr,we_mode}) // output
.we ({we_mode,we_addr}) // output
);
ram_var_w_var_r #(
......@@ -419,9 +419,9 @@ module histogram_saxi#(
.clk (aclk), // input
.sync_rst (!en_aclk), // input
.we (buf_re[2]), // input
.re (), // input
.data_in (inter_buf_data), // input[15:0]
.data_out (saxi_wdata), // output[15:0]
.re (fifo_re), // input
.data_in (inter_buf_data), // input[31:0]
.data_out (saxi_wdata), // output[31:0]
.nempty (fifo_nempty), // output
.half_full (fifo_half_full) // output reg
);
......
axi/mul_saxi_wr_chn.v 0 → 100644
View file @ 5d61e6fb
/*******************************************************************************
* Module: mul_saxi_wr_chn
* Date:2015-07-10
* Author: andrey
* Description: One channel of the mult_saxi_wr (read/write common buffer)
*
* Copyright (c) 2015 Elphel, Inc .
* mul_saxi_wr_chn.v 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 3 of the License, or
* (at your option) any later version.
*
* mul_saxi_wr_chn.v 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, see <http://www.gnu.org/licenses/> .
*******************************************************************************/
`timescale 1ns/1ps
module mult_saxi_wr_chn #(
parameter MULT_SAXI_HALF_BRAM = 1, // 0 - use full 36Kb BRAM for the buffer, 1 - use just half
parameter MULT_SAXI_BSLOG = 4, // number of bits to represent burst size (4 - b.s. = 16, 0 - b.s = 1)
parameter MULT_SAXI_ADV_WR = 4, // number of clock cycles before end of write to genearte adv_wr_done
parameter MULT_SAXI_ADV_RD = 3 // number of clock cycles before end of read to genearte wdata_busy (if !fifo_half_full)
) (
input mclk, // system clock
input aclk, // global clock to run s_axi (@150MHz?)
input en, // enable this channle ( 0 - reset)
input has_burst, // channel has at least 1 burst (should go down immediately after read_burst if no more data)
// use grant_wr to request reading external data
// output read_burst, // request to read a burst of data from the channel
input valid, // data valid (same latency)
output rq_wr, // request to write to the buffer FIFO
input grant_wr, // single-cycle
output [(MULT_SAXI_HALF_BRAM?6:7):0] wa, // write buffer address (w/o 2 MSB - channel)
output reg adv_wr_done, // outputs grant_wr for short bursts, or several clocks before end of wr
// output pre_we, // will be registered after mux - use valid
output reg rq_out,
input grant_out, // single-cycle
input fifo_half_full, // output fifo is half full - use it to suspend readout
output [(MULT_SAXI_HALF_BRAM?6:7):0] ra, // read buffer address (w/o 2 MSB - channel)
output pre_re, // will be registerd after the MUX
output reg first_re, // reading first word (next cycle after corresponding pre_re)
output reg last_re, // reading lastt word (next cycle after corresponding pre_re)
output reg wdata_busy
);
localparam BURSTS_BITS= (MULT_SAXI_HALF_BRAM ? 9 : 10 ) - MULT_SAXI_BSLOG - 2; // number of bits to count number of bursts in 0-th quarter of the buffer
reg [BURSTS_BITS-1:0] wr_burst;
reg [MULT_SAXI_BSLOG-1:0] wr_word;
reg [BURSTS_BITS:0] wr_num_burst; // number of bursts in the buffer chn0, as seen from the write side
reg [BURSTS_BITS-1:0] rd_burst;
reg [MULT_SAXI_BSLOG-1:0] rd_word;
reg [BURSTS_BITS:0] rd_num_burst; // number of bursts in the buffer chn0, as seen from the read side
reg rq_wr_r;
reg rq_wr_busy;
// reg early_wr_done; // single-cycle pulse several clock before end of write busy
// reg grant_wr_r;
// wire grant_wr_sngl;
// wire grant_wr_aclk;
wire write_last_in_burst;
wire burst_written_aclk;
// reg grant_out_r;
// wire grant_out_sngl;
wire grant_out_mclk;
reg en_aclk;
wire last_word_busy;
reg pre_re_r; // may be interrupted if fifo_half_full
reg out_busy; // output data in progress
assign wa = {wr_burst, wr_word};
assign ra = {rd_burst, rd_word};
assign rq_wr = rq_wr_r;
// assign grant_wr_sngl = grant_wr && !grant_wr_r;
// assign grant_out_sngl = grant_out && ~grant_out_r;
assign last_word_busy = &wr_word ; // make it earlier, use BURSTS_BITS selection (& (word | (1 <<???)))
assign write_last_in_burst = valid && (&wr_word);
assign pre_re = pre_re_r;
localparam ADV_WR_COUNT=(1 << MULT_SAXI_BSLOG) - MULT_SAXI_ADV_WR;
localparam ADV_RD_COUNT=(1 << MULT_SAXI_BSLOG) - MULT_SAXI_ADV_RD;
always @ (posedge mclk) begin
adv_wr_done <= rq_wr_busy && (wr_word == ((ADV_WR_COUNT >= 0)? ADV_WR_COUNT : 0));
if (!en) rq_wr_busy <= 0;
else if (grant_wr) rq_wr_busy <= 1;
else if (valid && last_word_busy) rq_wr_busy <= 0;
rq_wr_r <= has_burst & (~wr_num_burst[BURSTS_BITS] & ~(&wr_num_burst[BURSTS_BITS-1:0])) & ~grant_wr & ~rq_wr_busy;
// Number of bursts in fifo as seen from the input
if (!en) wr_num_burst <= 0;
else if ( grant_wr && !grant_out_mclk) wr_num_burst <= wr_num_burst + 1;
else if (!grant_wr && grant_out_mclk) wr_num_burst <= wr_num_burst - 1;
if (!en || grant_wr) wr_word <= 0;
else if (valid) wr_word <= wr_word + 1;
if (!en) wr_burst <= 0;
else if (write_last_in_burst) wr_burst <= wr_burst + 1;
end
reg early_busy; // output data in progress
always @ (posedge aclk) begin
en_aclk <= en;
// Number of bursts in fifo as seen from the output
if (!en_aclk) rd_num_burst <= 0;
else if ( burst_written_aclk && !grant_out) rd_num_burst <= rd_num_burst + 1;
else if (!burst_written_aclk && grant_out) rd_num_burst <= rd_num_burst - 1;
if (!en_aclk) rq_out <= 0;
else if ( burst_written_aclk && !grant_out) rq_out <= 1;
else if (!burst_written_aclk && grant_out) rq_out <= |rd_num_burst[BURSTS_BITS:1]; // >=2
if (! en_aclk || grant_out) rd_word <= 0;
else if (pre_re_r) rd_word <=rd_word +1;
if (!en_aclk) rd_burst <= wr_burst; // <= 0 is OK too
else if (pre_re_r && (&rd_word)) rd_burst <= rd_burst + 1;
if (!en_aclk) out_busy <= 0;
else if (grant_out) out_busy <= 1;
else if ((&rd_word) && pre_re_r) out_busy <= 0;
if (!en_aclk || fifo_half_full || ((&rd_word) && pre_re_r)) pre_re_r <= 0;
else pre_re_r <= out_busy;
first_re <= pre_re_r && !(|rd_word); // will be used to copy channel/axi_wid
last_re <= pre_re_r && (&rd_word); // will be used to generate axi_wlast
if (!en_aclk || (ADV_RD_COUNT > 0)) early_busy <= 0; // small counts will never get busy
else if (grant_out) early_busy <= 1;
else if (rd_word == ADV_RD_COUNT) early_busy <= 0;
if (!en_aclk) wdata_busy <= 0;
else if (grant_out) wdata_busy <= 1;
else if ((!fifo_half_full && !early_busy) || (&rd_word) || !out_busy) wdata_busy <= 0;
end
pulse_cross_clock grant_out_mclk_i (
.rst (!en), // input
.src_clk (aclk), // input
.dst_clk (mclk), // input
.in_pulse (grant_out), // input
.out_pulse (grant_out_mclk), // output
.busy() // output
);
pulse_cross_clock write_last_in_burst_i (
.rst (!en_aclk), // input
.src_clk (mclk), // input
.dst_clk (aclk), // input
.in_pulse (write_last_in_burst), // input
.out_pulse (burst_written_aclk), // output
.busy() // output
);
endmodule
axi/mult_saxi_wr.v 0 → 100644
View file @ 5d61e6fb
/*******************************************************************************
* Module: mult_saxi_wr
* Date:2015-07-08
* Author: andrey
* Description: send data from up to 4 sources to the system memory over S_AXI.
* Each source should have a 32-bit wide buffer running at the same clock (mclk).
* Buffer should contain at least burst size (4,8,16,32,64 bytes)
* Burst size parameter-configurable (per-port)
*
* Copyright (c) 2015 Elphel, Inc .
* mult_saxi_wr.v 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 3 of the License, or
* (at your option) any later version.
*
* mult_saxi_wr.v 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, see <http://www.gnu.org/licenses/> .
*******************************************************************************/
`timescale 1ns/1ps
module mult_saxi_wr #(
parameter MULT_SAXI_ADDR = 'h380, // need to modify addresses and masks to fit into overall command range
parameter MULT_SAXI_CNTRL_ADDR = 'h3a0, //
parameter MULT_SAXI_STATUS_REG = 'h30, // uses 4 consecutive locations
parameter MULT_SAXI_HALF_BRAM = 1, // 0 - use full 36Kb BRAM for the buffer, 1 - use just half
parameter MULT_SAXI_BSLOG0 = 4, // number of bits to represent burst size (4 - b.s. = 16, 0 - b.s = 1)
parameter MULT_SAXI_BSLOG1 = 4,
parameter MULT_SAXI_BSLOG2 = 4,
parameter MULT_SAXI_BSLOG3 = 4,
parameter MULT_SAXI_MASK = 'h3f8, // 4 address/length pairs. In bytes, but lower bits are set to 0?
parameter MULT_SAXI_CNTRL_MASK = 'h3fe, // mode and status - 2 locations
parameter HIST_SAXI_AWCACHE = 4'h3, //..7 cache mode (4 bits, default 4'h3)
parameter MULT_SAXI_ADV_WR = 4, // number of clock cycles before end of write to genearte adv_wr_done
parameter MULT_SAXI_ADV_RD = 3 // number of clock cycles before end of write to genearte adv_wr_done
) (
input rst, // global reset
input mclk, // system clock
input aclk, // global clock to run s_axi (@150MHz?)
// command interface
input [7:0] cmd_ad, // byte-serial command address/data (up to 6 bytes: AL-AH-D0-D1-D2-D3
input cmd_stb, // strobe (with first byte) for the command a/d
output [7:0] status_ad, // status address/data - up to 5 bytes: A - {seq,status[1:0]} - status[2:9] - status[10:17] - status[18:25]
output status_rq, // input request to send status downstream
input status_start, // Acknowledge of the first status packet byte (address)
input has_burst0, // channel has at least 1 burst (should go down immediately after read_burst0 if no more data)
output read_burst0, // request to read a burst of data from channel 0
input [31:0] data_in_chn0, // data read from channel 0 (with some latency)
input pre_valid_chn0,// data valid (same latency)
input has_burst1, // channel has at least 1 burst (should go down immediately after read_burst0 if no more data)
output read_burst1, // request to read a burst of data from channel 0
input [31:0] data_in_chn1, // data read from channel 0 (with some latency)
input pre_valid_chn1,// data valid (same latency)
input has_burst2, // channel has at least 1 burst (should go down immediately after read_burst0 if no more data)
output read_burst2, // request to read a burst of data from channel 0
input [31:0] data_in_chn2, // data read from channel 0 (with some latency)
input pre_valid_chn2,// data valid (same latency)
input has_burst3, // channel has at least 1 burst (should go down immediately after read_burst0 if no more data)
output read_burst3, // request to read a burst of data from channel 0
input [31:0] data_in_chn3, // data read from channel 0 (with some latency)
input pre_valid_chn3,// data valid (same latency)
// S_AXI inerface w/o read channel
// write address
output [31:0] saxi_awaddr, // AXI PS Slave GP0 AWADDR[31:0], input
output saxi_awvalid, // AXI PS Slave GP0 AWVALID, input
input saxi_awready, // AXI PS Slave GP0 AWREADY, output
output [5:0] saxi_awid, // AXI PS Slave GP0 AWID[5:0], input
output [1:0] saxi_awlock, // AXI PS Slave GP0 AWLOCK[1:0], input
output [ 3:0] saxi_awcache, // AXI PS Slave GP0 AWCACHE[3:0], input
output [ 2:0] saxi_awprot, // AXI PS Slave GP0 AWPROT[2:0], input
output [ 3:0] saxi_awlen, // AXI PS Slave GP0 AWLEN[3:0], input
output [ 1:0] saxi_awsize, // AXI PS Slave GP0 AWSIZE[1:0], input
output [ 1:0] saxi_awburst, // AXI PS Slave GP0 AWBURST[1:0], input
output [ 3:0] saxi_awqos, // AXI PS Slave GP0 AWQOS[3:0], input
// write data
output [31:0] saxi_wdata, // AXI PS Slave GP0 WDATA[31:0], input
output saxi_wvalid, // AXI PS Slave GP0 WVALID, input
input saxi_wready, // AXI PS Slave GP0 WREADY, output
output [ 5:0] saxi_wid, // AXI PS Slave GP0 WID[5:0], input
output saxi_wlast, // AXI PS Slave GP0 WLAST, input
output [ 3:0] saxi_wstrb, // AXI PS Slave GP0 WSTRB[3:0], input
// write response Not used - may add guaranteed address (as for the histogram)?
input saxi_bvalid, // AXI PS Slave GP0 BVALID, output // @SuppressThisWarning VEditor unused
output saxi_bready, // AXI PS Slave GP0 BREADY, input // @SuppressThisWarning VEditor unused
input [ 5:0] saxi_bid, // AXI PS Slave GP0 BID[5:0], output //TODO: Update range !!! // @SuppressThisWarning VEditor unused
input [ 1:0] saxi_bresp // AXI PS Slave GP0 BRESP[1:0], output // @SuppressThisWarning VEditor unused
);
// parameter MULT_SAXI_BSLOG0 = 4, // number of bits to represent burst size (4 - b.s. = 16, 0 - b.s = 1)
// localparam BURSTS_CAP0= (MULT_SAXI_HALF_BRAM ? 'h400 : 'h800 ) / MULT_SAXI_BURST0 / 4;
localparam BRAM_A_WDTH = MULT_SAXI_HALF_BRAM?9:10;
wire [3:0] en_chn_mclk;
wire [3:0] run_chn_mclk;
reg [7:0] mode_reg;
wire en_mclk= |en_chn_mclk; // at least one channel enabled
reg [3:0] en_chn_aclk;
wire en_aclk= |en_chn_aclk; // at least one channel enabled
wire [3:0] rq_wr;
wire [3:0] grant_wr;
wire [BRAM_A_WDTH-3:0] wa_chn[0:3];
wire [3:0] adv_wr_done; // outputs grant_wr for short bursts, or several clocks before end of wr
wire [3:0] rq_out_chn;
wire [BRAM_A_WDTH-3:0] ra_chn[0:3];
wire [3:0] pre_re;
reg en_we_arb; // @mclk should be reset by we_grant
wire we_grant; // @mclk
wire [1:0] we_cur_chn; // @mclk
wire [31:0] data_in[0:3];
wire [3:0] pre_valid;
reg [3:0] valid;
reg [BRAM_A_WDTH-1:0] buf_wa; // multiplexed buffer write adderss
reg [31:0] buf_wd; // multiplexed buffer write data
reg buf_we; // multiplexed buffer write enable
wire [3:0] grant_rd;
wire grant_rd_any;
wire en_out_arb;
wire [1:0] re_cur_chn;
reg [BRAM_A_WDTH-1:0] buf_ra; // multiplexed buffer write adderss
wire [31:0] inter_buf_data; // multiplexed buffer write data
reg [2:0] buf_re; // multiplexed buffer write enable
wire fifo_half_full; // output FIFO saxi_wdata is half full (stop writing to)
wire fifo_nempty; // output FIFO saxi_wdata is not empty (can read)
wire [3:0] wdata_busy_chn; // output data busy (ends early to start next arbitration)
wire [3:0] first_re; // reading first word in a burst from the buffer
wire [3:0] last_re; // reading first word in a burst from the buffer
wire [3:0] cmd_a;
wire [31:0] cmd_data;
wire we_ctrl;
wire cmd_we_sa_len;
always @ (posedge rst or posedge mclk) begin
if (rst) mode_reg <= 0;
else if (we_ctrl && !cmd_a[0]) mode_reg <= cmd_data[7:0];
end
assign {read_burst3, read_burst2, read_burst1, read_burst0} = grant_wr; // single clock pulse
assign data_in[0] = data_in_chn0;
assign data_in[1] = data_in_chn1;
assign data_in[2] = data_in_chn2;
assign data_in[3] = data_in_chn3;
assign pre_valid = {pre_valid_chn3, pre_valid_chn2, pre_valid_chn1, pre_valid_chn0};
assign en_chn_mclk = mode_reg[3:0];
assign run_chn_mclk = mode_reg[7:4];
// Arbiter requests on copying from one of teh input channels to the internal buffer
mult_saxi_wr_chn #(
.MULT_SAXI_HALF_BRAM (MULT_SAXI_HALF_BRAM),
.MULT_SAXI_BSLOG (MULT_SAXI_BSLOG0),
.MULT_SAXI_ADV_WR (MULT_SAXI_ADV_WR),
.MULT_SAXI_ADV_RD (MULT_SAXI_ADV_RD)
) mult_saxi_wr_sub0_i (
.mclk (mclk), // input
.aclk (aclk), // input
.en (en_chn_mclk[0]), // input
.has_burst (has_burst0), // input
.valid (valid[0]), // input
.rq_wr (rq_wr[0]), // output
.grant_wr (grant_wr[0]), // input
.wa (wa_chn[0]), // output[7:0]
.adv_wr_done (adv_wr_done[0]), // output
.rq_out (rq_out_chn[0]), // output reg
.grant_out (grant_rd[0]), // input
.fifo_half_full(fifo_half_full), // input
.ra (ra_chn[0]), // output[7:0]
.pre_re (pre_re[0]), // output
.first_re (first_re[0]), // output reg // 1 clock later than pre_re
.last_re (last_re[0]), // output reg // 1 clock later than pre_re
.wdata_busy (wdata_busy_chn[0]) // output reg
);
mult_saxi_wr_chn #(
.MULT_SAXI_HALF_BRAM (MULT_SAXI_HALF_BRAM),
.MULT_SAXI_BSLOG (MULT_SAXI_BSLOG1),
.MULT_SAXI_ADV_WR (MULT_SAXI_ADV_WR),
.MULT_SAXI_ADV_RD (MULT_SAXI_ADV_RD)
) mult_saxi_wr_sub1_i (
.mclk (mclk), // input
.aclk (aclk), // input
.en (en_chn_mclk[1]), // input
.has_burst (has_burst1), // input
.valid (valid[1]), // input
.rq_wr (rq_wr[1]), // output
.grant_wr (grant_wr[1]), // input
.wa (wa_chn[1]), // output[7:0]
.adv_wr_done (adv_wr_done[1]), // output
.rq_out (rq_out_chn[1]), // output reg
.grant_out (grant_rd[1]), // input
.fifo_half_full(fifo_half_full), // input
.ra (ra_chn[1]), // output[7:0]
.pre_re (pre_re[1]), // output
.first_re (first_re[1]), // output reg // 1 clock later than pre_re
.last_re (last_re[1]), // output reg // 1 clock later than pre_re
.wdata_busy (wdata_busy_chn[1]) // output reg
);
mult_saxi_wr_chn #(
.MULT_SAXI_HALF_BRAM (MULT_SAXI_HALF_BRAM),
.MULT_SAXI_BSLOG (MULT_SAXI_BSLOG2),
.MULT_SAXI_ADV_WR (MULT_SAXI_ADV_WR),
.MULT_SAXI_ADV_RD (MULT_SAXI_ADV_RD)
) mult_saxi_wr_sub2_i (
.mclk (mclk), // input
.aclk (aclk), // input
.en (en_chn_mclk[2]), // input
.has_burst (has_burst2), // input
.valid (valid[2]), // input
.rq_wr (rq_wr[2]), // output
.grant_wr (grant_wr[2]), // input
.wa (wa_chn[2]), // output[7:0]
.adv_wr_done (adv_wr_done[2]), // output
.rq_out (rq_out_chn[2]), // output reg
.grant_out (grant_rd[2]), // input
.fifo_half_full(fifo_half_full), // input
.ra (ra_chn[2]), // output[7:0]
.pre_re (pre_re[2]), // output
.first_re (first_re[2]), // output reg // 1 clock later than pre_re
.last_re (last_re[2]), // output reg // 1 clock later than pre_re
.wdata_busy (wdata_busy_chn[2]) // output reg
);
mult_saxi_wr_chn #(
.MULT_SAXI_HALF_BRAM (MULT_SAXI_HALF_BRAM),
.MULT_SAXI_BSLOG (MULT_SAXI_BSLOG3),
.MULT_SAXI_ADV_WR (MULT_SAXI_ADV_WR),
.MULT_SAXI_ADV_RD (MULT_SAXI_ADV_RD)
) mult_saxi_wr_sub3_i (
.mclk (mclk), // input
.aclk (aclk), // input
.en (en_chn_mclk[3]), // input
.has_burst (has_burst3), // input
.valid (valid[3]), // input
.rq_wr (rq_wr[3]), // output
.grant_wr (grant_wr[3]), // input
.wa (wa_chn[3]), // output[7:0]
.adv_wr_done (adv_wr_done[3]), // output
.rq_out (rq_out_chn[3]), // output reg
.grant_out (grant_rd[3]), // input
.fifo_half_full(fifo_half_full), // input
.ra (ra_chn[3]), // output[7:0]
.pre_re (pre_re[3]), // output
.first_re (first_re[3]), // output reg // 1 clock later than pre_re
.last_re (last_re[3]), // output reg // 1 clock later than pre_re
.wdata_busy (wdata_busy_chn[3]) // output reg
);
round_robin #(
.FIXED_PRIORITY (0), // 0 - round-robin, 1 - fixed channel priority (0 - highest)
.BITS (2) // number of bits to encode channel number (1 << BITS) - number of inputs
) round_robin_mclk_i (
.clk (mclk), // input
.srst (!en_mclk), // input sync. reset - needed to reset current channel output
.rq (rq_wr & run_chn_mclk), // input[3:0]
.en (en_we_arb), // input enable to grant highest priority request (should be reset by grant out)
.grant (we_grant), // output stays on until reset by !en
.chn (we_cur_chn), // output[1:0]
.grant_chn (grant_wr) // output[3:0] 1-hot grant output per-channel, single-clock pulse
);
// multiplex channel data to a common buffer
wire pre_pre_buf_we;
reg pre_buf_we;
reg [1:0] chn_wr;
assign pre_pre_buf_we = pre_valid[we_cur_chn];
always @ (posedge mclk) begin
// Use advanced 'valid' signal (from the input channel external buffers) to copy we_cur_chn
// to chn_wr - that allows to start arbitration (that will result in modification of the we_cur_chn)
// early, before write operation to the buffer (using channel for multiplexing and address MSB)
// is finished.
valid <= pre_valid;
pre_buf_we <= pre_pre_buf_we;
buf_we <= pre_buf_we; // valid[we_cur_chn];
if (pre_pre_buf_we && !pre_buf_we) chn_wr <= we_cur_chn; // to re-start arbitration early
// multiplex address and data
buf_wa <= {chn_wr, wa_chn[chn_wr]};
buf_wd <= data_in[chn_wr];
// early re-enable arbitration (en_we_arb)
if (!en_mclk || adv_wr_done[chn_wr]) en_we_arb <= 1;
else if (we_grant) en_we_arb <= 0;
// else if
end
// Buffer output to S_AXI (will need a smaller FIFO
reg [1:0] chn_rd;
reg [1:0] chn_rd_data; // channel valid with read data
reg pre_first_rd_valid; // first inter_buf_data in a burst will be valid next cycle
reg [1:0] is_last_rd; // [1] accompanies last inter_buf_data in a burst (to generate wlast)
wire [1:0] chn_fifo_out; // channel number out from fifo (for wid)
// wire is_last_fifo_out; // last data word out from fifo (for wlast)
always @ (posedge aclk) begin
en_chn_aclk <=en_chn_mclk;
chn_rd <= re_cur_chn; // delay by 1 clock (to increase overlap)
buf_ra <= {chn_rd, ra_chn[chn_rd]};
buf_re <= {buf_re[1:0], pre_re[chn_rd]};
pre_first_rd_valid <= first_re[chn_rd];
is_last_rd <= {is_last_rd[0], last_re[chn_rd]};
if (pre_first_rd_valid) chn_rd_data <= chn_rd; // extend to later time to use as wid with overlapping requests
// in parallel - read channel parameters (address, length, pointer)
end
round_robin #(
.FIXED_PRIORITY (0), // 0 - round-robin, 1 - fixed channel priority (0 - highest)
.BITS (2) // number of bits to encode channel number (1 << BITS) - number of inputs
) round_robin_aclk_i (
.clk (aclk), // input
.srst (!en_aclk), // input sync. reset - needed to reset current channel output
.rq (rq_out_chn), // input[3:0]
.en (en_out_arb), // input enable to grant highest priority request (should be reset by grant out)
.grant (grant_rd_any), // output stays on until reset by !en
.chn (re_cur_chn), // output[1:0]
.grant_chn (grant_rd) // output[3:0] 1-hot grant output per-channel, single-clock pulse
);
// Process address, length and current pointers (all in 32-bit words). Pointers are updated once per burst (parameter defined per each channel)
wire axi_ptr_busy; //
wire [29:0] axi_addr; //
wire [ 3:0] axi_len;
assign saxi_awaddr = {axi_addr,2'b0};
assign saxi_awlen = axi_len;
assign saxi_awlock= 2'h0; // AXI PS Slave GP0 AWLOCK[1:0], input
assign saxi_awcache= HIST_SAXI_AWCACHE; // awcache_mode; // 4'h3; // AXI PS Slave GP0 AWCACHE[3:0], input
assign saxi_awprot= 3'h0; // AXI PS Slave GP0 AWPROT[2:0], input
assign saxi_awsize= 2'h2; // 4 bytes; AXI PS Slave GP0 AWSIZE[1:0], input
assign saxi_awburst= 2'h1; // Increment address bursts AXI PS Slave GP0 AWBURST[1:0], input
assign saxi_awqos= 4'h0; // AXI PS Slave GP0 AWQOS[3:0], input
wire [29:0] pntr_wd; // @aclk, re-clock and write to status
wire [1:0] pntr_wa;
wire pntr_we;
mult_saxi_wr_pointers #(
.MULT_SAXI_BSLOG0 (MULT_SAXI_BSLOG0),
.MULT_SAXI_BSLOG1 (MULT_SAXI_BSLOG1),
.MULT_SAXI_BSLOG2 (MULT_SAXI_BSLOG2),
.MULT_SAXI_BSLOG3 (MULT_SAXI_BSLOG3)
) mult_saxi_wr_pointers_i (
.mclk (mclk), // input
.aclk (aclk), // input
.chn_en_mclk (en_chn_mclk), // input[3:0]
.sa_len_di (cmd_data[29:0]), // input[29:0]
.sa_len_wa (cmd_a[2:0]), // input[2:0]
.sa_len_we (cmd_we_sa_len), // input
.chn (re_cur_chn), // input[1:0]
.start (grant_rd_any), // input make sure 1 cycle
.busy (axi_ptr_busy), // output OR this busy with write data channel busy for en_out_arb
.axi_addr (axi_addr), // output[29:0] reg valid 2 cycles after start of grant_rd_any
.axi_len (axi_len), // output[3:0] reg
.pntr_wd (pntr_wd), // output[29:0]
.pntr_wa (pntr_wa), // output[1:0]
.pntr_we (pntr_we) // output
);
// interface axi_aw channel
reg awvalid; //
reg [2:0] aw_seq;
// wire aw_busy; // use to control en_out_arb = !(aw_busy || <data_channel_busy>);
reg [1:0] chn_out;
always @ (posedge aclk) begin
if (!en_aclk) aw_seq <= 0;
else aw_seq <= {aw_seq[1:0], grant_rd_any};
if (!en_aclk) awvalid <= 0;
else if (aw_seq[0]) awvalid <= 1;
else if (saxi_awready) awvalid <= 0;
if (grant_rd_any) chn_out <= re_cur_chn;
end
// assign aw_busy = axi_ptr_busy | awvalid;
assign saxi_awvalid = awvalid;
assign saxi_awid = {4'b0, chn_out};
assign en_out_arb = !(axi_ptr_busy || awvalid || (|wdata_busy_chn));
wire fifo_re;
assign fifo_re= saxi_wvalid && saxi_wready;
// s_axi write channel
// Small extra FIFO to tolerate ram_var_w_var_r latency
// assign fifo_re= saxi_wvalid && saxi_wready;
assign saxi_wid={4'b0, chn_fifo_out};
assign saxi_wvalid = en_aclk && fifo_nempty;
assign saxi_wstrb = 4'hf; // All bytes
always @ (posedge aclk) begin
end
fifo_same_clock #(
.DATA_WIDTH(35),
.DATA_DEPTH(4)
) fifo_same_clock_i (
.rst (rst), // input
.clk (aclk), // input
.sync_rst (!en_aclk), // input
.we (buf_re[2]), // input
.re (fifo_re), // input
.data_in ({chn_rd_data,is_last_rd[1],inter_buf_data}), // input[31:0]
.data_out ({chn_fifo_out,saxi_wlast, saxi_wdata}), // output[31:0]
.nempty (fifo_nempty), // output
.half_full (fifo_half_full) // output reg
);
generate
if (MULT_SAXI_HALF_BRAM)
ram18_var_w_var_r #(
.REGISTERS(1),
.LOG2WIDTH_WR(5),
.LOG2WIDTH_RD(5),
.DUMMY(0)
) ram_var_w_var_r_i (
.rclk (aclk), // input
.raddr (buf_ra[8:0]), // input[9:0]
.ren (buf_re[0]), // input
.regen (buf_re[1]), // input
.data_out (inter_buf_data), // output[31:0]
.wclk (mclk), // input
.waddr (buf_wa[8:0]), // input[9:0]
.we (buf_we), // input
.web (4'hff), // input[7:0]
.data_in (buf_wd) // input[31:0]
);
else
ram_var_w_var_r #(
.REGISTERS(1),
.LOG2WIDTH_WR(5),
.LOG2WIDTH_RD(5),
.DUMMY(0)
) ram_var_w_var_r_i (
.rclk (aclk), // input
.raddr ({buf_ra[BRAM_A_WDTH-1],buf_ra[8:0]}), // input[9:0]
.ren (buf_re[0]), // input
.regen (buf_re[1]), // input
.data_out (inter_buf_data), // output[31:0]
.wclk (mclk), // input
.waddr ({buf_wa[BRAM_A_WDTH-1],buf_wa[8:0]}), // input[9:0]
.we (buf_we), // input
.web (8'hff), // input[7:0]
.data_in (buf_wd) // input[31:0]
);
endgenerate
cmd_deser #(
.ADDR (MULT_SAXI_ADDR),
.ADDR_MASK (MULT_SAXI_MASK),
.NUM_CYCLES (6),
.ADDR_WIDTH (4),
.DATA_WIDTH (32),
.ADDR1 (MULT_SAXI_CNTRL_ADDR),
.ADDR_MASK1 (MULT_SAXI_CNTRL_MASK),
.ADDR2 (0),
.ADDR_MASK2 (0)
) cmd_deser_sens_i2c_i (
.rst (rst), // input
.clk (mclk), // input
.ad (cmd_ad), // input[7:0]
.stb (cmd_stb), // input
.addr (cmd_a), // output[3:0]
.data (cmd_data), // output[31:0]
.we ({cmd_we_sa_len,we_ctrl}) // output
);
// now - converting all to parallel (TODO: use RAM for multi-word status data)
reg [29:0] status_pntr0;
reg [29:0] status_pntr1;
reg [29:0] status_pntr2;
reg [29:0] status_pntr3;
wire pntr_we_mclk;
wire [128:0] status_data;
reg status_tgl;
assign status_data = {2'b0, status_pntr3, 2'b0, status_pntr2, 2'b0, status_pntr1, 2'b0, status_pntr0, status_tgl};
always @ (posedge mclk) begin
if (!en_mclk) status_tgl <= 0;
else if (pntr_we_mclk) status_tgl <= ~status_tgl;
if (pntr_we_mclk && (pntr_wa == 2'h0)) status_pntr0 <= pntr_wd;
if (pntr_we_mclk && (pntr_wa == 2'h1)) status_pntr1 <= pntr_wd;
if (pntr_we_mclk && (pntr_wa == 2'h2)) status_pntr2 <= pntr_wd;
if (pntr_we_mclk && (pntr_wa == 2'h3)) status_pntr3 <= pntr_wd;
end
pulse_cross_clock status_wr_i (.rst(rst), .src_clk(aclk), .dst_clk(mclk), .in_pulse(pntr_we), .out_pulse(pntr_we_mclk),.busy());
status_generate #(
.STATUS_REG_ADDR (MULT_SAXI_STATUS_REG+4), // not used
.PAYLOAD_BITS (0),
.REGISTER_STATUS (1),
.EXTRA_WORDS (4),
.EXTRA_REG_ADDR (MULT_SAXI_STATUS_REG)
) status_generate_i (
.rst (rst), // input
.clk (mclk), // input
.we (we_ctrl && cmd_a[0]), // input
.wd (cmd_data[7:0]), // input[7:0]
.status (status_data), // input[128:0]
.ad (status_ad), // output[7:0]
.rq (status_rq), // output
.start (status_start) // input
);
endmodule
axi/mult_saxi_wr_pointers.v 0 → 100644
View file @ 5d61e6fb
/*******************************************************************************
* Module: mult_saxi_wr_pointers
* Date:2015-07-10
* Author: andrey
* Description: Process pointers for mult_saxi_wr
*
* Copyright (c) 2015 Elphel, Inc .
* mult_saxi_wr_pointers.v 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 3 of the License, or
* (at your option) any later version.
*
* mult_saxi_wr_pointers.v 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, see <http://www.gnu.org/licenses/> .
*******************************************************************************/
`timescale 1ns/1ps
module mult_saxi_wr_pointers#(
parameter MULT_SAXI_BSLOG0 = 4, // number of bits to represent burst size (4 - b.s. = 16, 0 - b.s = 1)
parameter MULT_SAXI_BSLOG1 = 4,
parameter MULT_SAXI_BSLOG2 = 4,
parameter MULT_SAXI_BSLOG3 = 4
)(
input mclk, // system clock
input aclk, // global clock to run s_axi (@150MHz?)
input [3:0] chn_en_mclk, // enable this channle ( 0 - reset)
input [29:0] sa_len_di, // input data to write pointers address/data
input [ 2:0] sa_len_wa, // channel address to write sa/lengths
input sa_len_we, // write enable sa/length data
input [ 1:0] chn, // selected channel number, valid with start
input start, // start address generation/pointer increment
output busy, // suspend new accesses (check latencies)
// provide address and burst length for AXI @aclk, will stay until ackn
output reg [29:0] axi_addr,
output reg [3:0] axi_len,
// write data to external pointre memory (to be read out by PIO) @ aclk
// alternatively - read out directly from ptr_ram?
output [29:0] pntr_wd, // @aclk
output [1:0] pntr_wa,
output pntr_we
);
reg [3:0] chn_en_mclk_r;
reg [3:0] chn_en_aclk;
wire rst = !(|chn_en_mclk); // just for simulation
wire rst_aclk = !(|chn_en_aclk); // just for simulation
wire [3:0] chn_wr_mclk = {(sa_len_wa[2:1]==3),(sa_len_wa[2:1]==2),(sa_len_wa[2:1]==1),(sa_len_wa[2:1]==0)};
wire [3:0] rst_pntr_mclk = (chn_en_mclk & ~chn_en_mclk_r) | (sa_len_we ? chn_wr_mclk : 4'b0);
wire [3:0] rst_pntr_aclk;
wire start_resetting_w;
reg [1:0] resetting; // resetting chunk_pointer and eof_pointer
reg busy_r;
reg [3:0] reset_rq; // request to reset pointers when ready
reg [3:0] reset_rq_pri; // one-hot reset rq
wire [1:0] reset_rq_enc; // encoded reset_rq_pri
wire en_aclk = |chn_en_aclk;
reg [1:0] chn_r; // registered channel being processed (or reset)
reg [1:0] seq; // 1-hot sequence of address generation
wire [29:0] sa_len_ram_out;
wire [29:0] ptr_ram_out;
wire [2:0] sa_len_ra;
reg ptr_we; // write to the pointer memory
reg [29:0] ptr_inc; // incremented pointer
reg [30:0] ptr_rollover;
reg [4:0] burst_size; // ROM
wire [29:0] ptr_wd;
assign reset_rq_enc = {reset_rq_pri[3] | reset_rq_pri[2],
reset_rq_pri[3] | reset_rq_pri[1]};
assign start_resetting_w = en_aclk && !busy_r && !resetting[0] && (|reset_rq);
assign busy = busy_r; //?
assign ptr_wd = resetting[1] ? 30'b0 : (ptr_rollover[30]? ptr_inc : ptr_rollover[29:0]);
assign pntr_wd = ptr_wd;
assign pntr_we = ptr_we;
assign pntr_wa = chn_r;
assign sa_len_ra = {chn_r,seq[1]};
always @ (posedge mclk) begin
chn_en_mclk_r <= chn_en_mclk;
end
// 8x30 RAM for address/length
reg [29:0] sa_len_ram[0:7]; // start chunk/num cunks in a buffer (write port @mclk)
always @ (posedge mclk) begin
if (sa_len_we) sa_len_ram[sa_len_wa] <= sa_len_di;
end
assign sa_len_ram_out = sa_len_ram[sa_len_ra];
// 4 x 30 RAM for current pointers
reg [29:0] ptr_ram[0:3]; // start chunk/num cunks in a buffer (write port @mclk)
always @ (posedge aclk) begin
if (ptr_we) ptr_ram[chn_r] <= ptr_wd;
end
assign ptr_ram_out = ptr_ram[chn_r];
always @ (posedge aclk) if (start) case (chn) // small ROM
'h0 : burst_size <= 1 << MULT_SAXI_BSLOG0;
'h1 : burst_size <= 1 << MULT_SAXI_BSLOG1;
'h2 : burst_size <= 1 << MULT_SAXI_BSLOG2;
'h3 : burst_size <= 1 << MULT_SAXI_BSLOG3;
endcase
always @ (posedge aclk) begin
chn_en_aclk <= chn_en_mclk;
reset_rq <= rst_pntr_aclk | (reset_rq & ~({4{resetting[0] &~ resetting[1]}} & reset_rq_pri));
if (start_resetting_w) reset_rq_pri <= {reset_rq[3] & ~(|reset_rq[2:0]),
reset_rq[2] & ~(|reset_rq[1:0]),
reset_rq[1] & ~reset_rq[0],
reset_rq[0]};
if (rst_aclk) resetting <= 0;
else resetting <= {resetting[0], start_resetting_w | (resetting[0] & ~resetting[1])};
if (rst_aclk) busy_r <= 0;
else if (start_resetting_w || start) busy_r <= 1;
else if (ptr_we) busy_r <= 0;
if (rst_aclk) seq <= 0;
else seq <= {seq[0],start};
if (resetting == 2'b1) chn_r[1:0] <= reset_rq_enc; // during reset pointers
else if (start) chn_r[1:0] <= chn; // during normal address generation
if (seq[0]) axi_addr <= sa_len_ram_out + ptr_ram_out;
if (seq[0]) case (chn_r) // small ROM
'h0 : axi_len <= (1 << MULT_SAXI_BSLOG0) - 1;
'h1 : axi_len <= (1 << MULT_SAXI_BSLOG1) - 1;
'h2 : axi_len <= (1 << MULT_SAXI_BSLOG2) - 1;
'h3 : axi_len <= (1 << MULT_SAXI_BSLOG3) - 1;
endcase
if (seq[0]) ptr_inc <= ptr_ram_out + burst_size;
if (seq[1]) ptr_rollover <= {1'b0, ptr_inc} -sa_len_ram_out; //sa_len_ram_out is now length
ptr_we <= resetting[0] || seq[1];
// add one extra register layer here?
end
pulse_cross_clock #(.EXTRA_DLY(1)) rst_pntr_aclk0_i (.rst(rst), .src_clk(mclk), .dst_clk(aclk), .in_pulse(rst_pntr_mclk[0]), .out_pulse(rst_pntr_aclk[0]),.busy());
pulse_cross_clock #(.EXTRA_DLY(1)) rst_pntr_aclk1_i (.rst(rst), .src_clk(mclk), .dst_clk(aclk), .in_pulse(rst_pntr_mclk[1]), .out_pulse(rst_pntr_aclk[1]),.busy());
pulse_cross_clock #(.EXTRA_DLY(1)) rst_pntr_aclk2_i (.rst(rst), .src_clk(mclk), .dst_clk(aclk), .in_pulse(rst_pntr_mclk[2]), .out_pulse(rst_pntr_aclk[2]),.busy());
pulse_cross_clock #(.EXTRA_DLY(1)) rst_pntr_aclk3_i (.rst(rst), .src_clk(mclk), .dst_clk(aclk), .in_pulse(rst_pntr_mclk[3]), .out_pulse(rst_pntr_aclk[3]),.busy());
endmodule
util_modules/round_robin.v 0 → 100644
View file @ 5d61e6fb
/*******************************************************************************
* Module: round_robin
* Date:2015-07-10
* Author: andrey
* Description: Round-robin arbiter
*
* Copyright (c) 2015 Elphel, Inc .
* round_robin.v 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 3 of the License, or
* (at your option) any later version.
*
* round_robin.v 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, see <http://www.gnu.org/licenses/> .
*******************************************************************************/
`timescale 1ns/1ps
module round_robin #(
parameter FIXED_PRIORITY = 0, // 0 - round-robin, 1 - fixed channel priority (0 - highest)
parameter BITS = 2 // number of bits to encode channel number (1 << BITS) - number of inputs
)(
input clk,
input srst, // sync. reset - needed to reset current channel
input [(1 << BITS) -1:0] rq, // request vector
input en, // enable to grant highest priority request (should be reset by grant)
output reg grant, // changed to 1-cycle long (was: stays on until reset by !en)
output [BITS-1:0] chn,
output reg [(1 << BITS) -1:0] grant_chn); // 1-hot grant output per-channel, single-clock pulse
reg [BITS-1:0] last_chn;
wire valid;
wire [BITS-1:0] next_chn;
wire pre_grant_w;
reg grant_r;
assign pre_grant_w = en && valid &&!grant_r;
// assign grant = grant_r;
assign chn = last_chn;
assign {valid, next_chn}= func_selrr (rq, FIXED_PRIORITY?((1 << BITS) -1):last_chn);
always @ (posedge clk) begin
if (srst) last_chn <= (1 << BITS) -1;
else if (pre_grant_w) last_chn <= next_chn;
if (srst || !en) grant_r <= 0;
else if (valid) grant_r <= 1; // grant will stay on until reset by !en
grant_chn <= func_demux (!srst && pre_grant_w, next_chn);
grant <= !srst && pre_grant_w;
end
// round-robin priority encode
function [BITS : 0] func_selrr; // returns {valid, chn}
input [(1 << BITS) -1:0] rq; // request vector
input [BITS-1:0] cur_chn; // current (last served) channel - lowest priority
reg valid; // at least one request
reg [BITS - 1:0] chn, sample_chn;
integer i;
begin
valid = 0;
chn = 0;
for (i = 0; i < (1 << BITS); i = i+1) begin
sample_chn = (cur_chn - i) % (1 << BITS);
if (rq[sample_chn]) begin
valid = 1;
chn = sample_chn;
end
end
func_selrr = {valid,chn};
end
endfunction
function [(1 << BITS) -1:0] func_demux;
input en;
input [BITS - 1:0] sel;
integer i;
begin
for (i=0; i < (1 << BITS); i = i + 1) begin
func_demux[i] = en && (sel == i);
end
end
endfunction
endmodule
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