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Moved LSU Bus interface control path into it's own module.

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This commit is contained in:
Ross Thompson 2021-12-29 17:12:20 -06:00
parent ac5746c721
commit 56d86f4dd5
4 changed files with 150 additions and 103 deletions
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5
wally-pipelined/regression/wave.do
View file

@ -213,15 +213,13 @@ add wave -noupdate -expand -group lsu /testbench/dut/hart/lsu/ReadDataWordMuxM
add wave -noupdate -expand -group lsu /testbench/dut/hart/lsu/ReadDataM
add wave -noupdate -expand -group lsu /testbench/dut/hart/lsu/WriteDataM
add wave -noupdate -expand -group lsu /testbench/dut/hart/lsu/SelUncachedAdr
add wave -noupdate -expand -group lsu -expand -group bus -color Gold /testbench/dut/hart/lsu/BusCurrState
add wave -noupdate -expand -group lsu -expand -group bus -color Gold /testbench/dut/hart/lsu/busfsm/BusCurrState
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/BusStall
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/LsuBusRead
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/LsuBusWrite
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/LsuBusAdr
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/LsuBusAck
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/LsuBusHWDATA
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/UnCachedLsuBusRead
add wave -noupdate -expand -group lsu -expand -group bus /testbench/dut/hart/lsu/UnCachedLsuBusWrite
add wave -noupdate -expand -group lsu -expand -group dcache -color Gold /testbench/dut/hart/lsu/dcache/dcachefsm/CurrState
add wave -noupdate -expand -group lsu -expand -group dcache /testbench/dut/hart/lsu/dcache/WayHit
add wave -noupdate -expand -group lsu -expand -group dcache /testbench/dut/hart/lsu/dcache/SRAMBlockWriteEnableM
@ -474,7 +472,6 @@ add wave -noupdate -group {pc selection} /testbench/dut/hart/ifu/PrivilegedNextP
add wave -noupdate -group {pc selection} /testbench/dut/hart/ifu/PrivilegedChangePCM
add wave -noupdate /testbench/dut/hart/priv/priv/csr/MEPC_REGW
add wave -noupdate /testbench/dut/hart/lsu/LocalLsuBusAdr
add wave -noupdate /testbench/dut/hart/lsu/BasePAdrMaskedM
TreeUpdate [SetDefaultTree]
WaveRestoreCursors {{Cursor 7} {36865 ns} 1} {{Cursor 5} {49445 ns} 1} {{Cursor 3} {35522 ns} 0} {{Cursor 4} {49574 ns} 1}
quietly wave cursor active 3

3
wally-pipelined/src/cache/dcache.sv vendored
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@ -53,8 +53,6 @@ module dcache
output logic [`PA_BITS-1:0] DCacheBusAdr,
output logic [`XLEN-1:0] ReadDataBlockSetsM [(`DCACHE_BLOCKLENINBITS/`XLEN)-1:0],
output logic SelFlush,
input logic [`DCACHE_BLOCKLENINBITS-1:0] DCacheMemWriteData,
@ -119,6 +117,7 @@ module dcache
logic SelEvict;
logic LRUWriteEn;
logic [NUMWAYS-1:0] VDWriteEnableWay;
logic SelFlush;
// Read Path CPU (IEU) side

136
wally-pipelined/src/lsu/busfsm.sv Normal file
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@ -0,0 +1,136 @@
///////////////////////////////////////////
// busfsm.sv
//
// Written: Ross Thompson ross1728@gmail.com
// Modified:
//
// Purpose: Load/Store Unit's interface to BUS
//
// A component of the Wally configurable RISC-V project.
//
// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy,
// modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
// OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
///////////////////////////////////////////
`include "wally-config.vh"
module busfsm #(parameter integer WordCountThreshold,
parameter integer LOGWPL)
(input logic clk,
input logic reset,
input logic IgnoreRequest,
input logic [1:0] LsuRWM,
input logic DCacheFetchLine,
input logic DCacheWriteLine,
input logic LsuBusAck,
input logic CPUBusy,
input logic CacheableM,
output logic BusStall,
output logic LsuBusWrite,
output logic LsuBusRead,
output logic DCacheBusAck,
output logic BusCommittedM,
output logic SelUncachedAdr,
output logic [LOGWPL-1:0] WordCount);
logic UnCachedLsuBusRead;
logic UnCachedLsuBusWrite;
logic CntEn, PreCntEn;
logic CntReset;
logic WordCountFlag;
logic [LOGWPL-1:0] NextWordCount;
typedef enum {STATE_BUS_READY,
STATE_BUS_FETCH,
STATE_BUS_WRITE,
STATE_BUS_UNCACHED_WRITE,
STATE_BUS_UNCACHED_WRITE_DONE,
STATE_BUS_UNCACHED_READ,
STATE_BUS_UNCACHED_READ_DONE,
STATE_BUS_CPU_BUSY} busstatetype;
(* mark_debug = "true" *) busstatetype BusCurrState, BusNextState;
flopenr #(LOGWPL)
WordCountReg(.clk(clk),
.reset(reset | CntReset),
.en(CntEn),
.d(NextWordCount),
.q(WordCount));
assign NextWordCount = WordCount + 1'b1;
assign WordCountFlag = (WordCount == WordCountThreshold[LOGWPL-1:0]);
assign CntEn = PreCntEn & LsuBusAck;
always_ff @(posedge clk)
if (reset) BusCurrState <= #1 STATE_BUS_READY;
else BusCurrState <= #1 BusNextState;
always_comb begin
case(BusCurrState)
STATE_BUS_READY: if(IgnoreRequest) BusNextState = STATE_BUS_READY;
else if(LsuRWM[0] & ~CacheableM) BusNextState = STATE_BUS_UNCACHED_WRITE;
else if(LsuRWM[1] & ~CacheableM) BusNextState = STATE_BUS_UNCACHED_READ;
else if(DCacheFetchLine) BusNextState = STATE_BUS_FETCH;
else if(DCacheWriteLine) BusNextState = STATE_BUS_WRITE;
STATE_BUS_UNCACHED_WRITE: if(LsuBusAck) BusNextState = STATE_BUS_UNCACHED_WRITE_DONE;
else BusNextState = STATE_BUS_UNCACHED_WRITE;
STATE_BUS_UNCACHED_READ: if(LsuBusAck) BusNextState = STATE_BUS_UNCACHED_READ_DONE;
else BusNextState = STATE_BUS_UNCACHED_READ;
STATE_BUS_UNCACHED_WRITE_DONE: if(CPUBusy) BusNextState = STATE_BUS_CPU_BUSY;
else BusNextState = STATE_BUS_READY;
STATE_BUS_UNCACHED_READ_DONE: if(CPUBusy) BusNextState = STATE_BUS_CPU_BUSY;
else BusNextState = STATE_BUS_READY;
STATE_BUS_CPU_BUSY: if(CPUBusy) BusNextState = STATE_BUS_CPU_BUSY;
else BusNextState = STATE_BUS_READY;
STATE_BUS_FETCH: if (WordCountFlag & LsuBusAck) BusNextState = STATE_BUS_READY;
else BusNextState = STATE_BUS_FETCH;
STATE_BUS_WRITE: if(WordCountFlag & LsuBusAck) BusNextState = STATE_BUS_READY;
else BusNextState = STATE_BUS_WRITE;
endcase
end
assign CntReset = BusCurrState == STATE_BUS_READY;
assign BusStall = (BusCurrState == STATE_BUS_READY & ~IgnoreRequest & ((~CacheableM & (|LsuRWM)) | DCacheFetchLine | DCacheWriteLine)) |
(BusCurrState == STATE_BUS_UNCACHED_WRITE) |
(BusCurrState == STATE_BUS_UNCACHED_READ) |
(BusCurrState == STATE_BUS_FETCH) |
(BusCurrState == STATE_BUS_WRITE);
assign PreCntEn = BusCurrState == STATE_BUS_FETCH | BusCurrState == STATE_BUS_WRITE;
assign UnCachedLsuBusWrite = (BusCurrState == STATE_BUS_READY & ~CacheableM & (LsuRWM[0])) |
(BusCurrState == STATE_BUS_UNCACHED_WRITE);
assign LsuBusWrite = UnCachedLsuBusWrite | (BusCurrState == STATE_BUS_WRITE);
assign UnCachedLsuBusRead = (BusCurrState == STATE_BUS_READY & ~CacheableM & (|LsuRWM[1])) |
(BusCurrState == STATE_BUS_UNCACHED_READ);
assign LsuBusRead = UnCachedLsuBusRead | (BusCurrState == STATE_BUS_FETCH);
assign DCacheBusAck = (BusCurrState == STATE_BUS_FETCH & WordCountFlag & LsuBusAck) |
(BusCurrState == STATE_BUS_WRITE & WordCountFlag & LsuBusAck);
assign BusCommittedM = BusCurrState != STATE_BUS_READY;
assign SelUncachedAdr = (BusCurrState == STATE_BUS_READY & (|LsuRWM & ~CacheableM)) |
(BusCurrState == STATE_BUS_UNCACHED_READ |
BusCurrState == STATE_BUS_UNCACHED_READ_DONE |
BusCurrState == STATE_BUS_UNCACHED_WRITE |
BusCurrState == STATE_BUS_UNCACHED_WRITE_DONE);
endmodule

109
wally-pipelined/src/lsu/lsu.sv
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@ -342,17 +342,15 @@ module lsu
localparam integer WORDSPERLINE = `DCACHE_BLOCKLENINBITS/`XLEN;
localparam integer LOGWPL = $clog2(WORDSPERLINE);
localparam integer BLOCKLEN = `DCACHE_BLOCKLENINBITS;
localparam integer WordCountThreshold = WORDSPERLINE - 1;
localparam integer BLOCKBYTELEN = BLOCKLEN/8;
localparam integer OFFSETLEN = $clog2(BLOCKBYTELEN);
// temp
logic WordCountFlag;
logic [`XLEN-1:0] FinalAMOWriteDataM, FinalWriteDataM;
(* mark_debug = "true" *) logic [`XLEN-1:0] PreLsuBusHWDATA;
logic SelFlush;
logic [`XLEN-1:0] ReadDataWordM;
logic [`DCACHE_BLOCKLENINBITS-1:0] DCacheMemWriteData;
@ -360,12 +358,7 @@ module lsu
logic [`XLEN-1:0] ReadDataWordMuxM;
logic [LOGWPL-1:0] WordCount, NextWordCount;
logic [`PA_BITS-1:0] BasePAdrMaskedM;
logic [OFFSETLEN-1:0] BasePAdrOffsetM;
logic CntEn, PreCntEn;
logic CntReset;
logic [`PA_BITS-1:0] DCacheBusAdr;
logic [`XLEN-1:0] ReadDataBlockSetsM [(`DCACHE_BLOCKLENINBITS/`XLEN)-1:0];
@ -375,8 +368,6 @@ module lsu
logic DCacheFetchLine;
logic DCacheBusAck;
logic UnCachedLsuBusRead;
logic UnCachedLsuBusWrite;
logic SelUncachedAdr;
@ -393,7 +384,6 @@ module lsu
.DCacheCommittedM,
.DCacheBusAdr,
.ReadDataBlockSetsM,
.SelFlush,
.DCacheMemWriteData,
.DCacheFetchLine,
.DCacheWriteLine,
@ -401,6 +391,8 @@ module lsu
);
// sub word selection for read and writes and optional amo alu.
mux2 #(`XLEN) UnCachedDataMux(.d0(ReadDataWordM),
.d1(DCacheMemWriteData[`XLEN-1:0]),
.s(SelUncachedAdr),
@ -429,15 +421,12 @@ module lsu
.HWDATA(FinalWriteDataM));
generate
if (`XLEN == 32) assign LsuBusSize = SelUncachedAdr ? LsuFunct3M : 3'b010;
else assign LsuBusSize = SelUncachedAdr ? LsuFunct3M : 3'b011;
endgenerate;
// Bus Side logic
// register the fetch data from the next level of memory.
// This register should be necessary for timing. There is no register in the uncore or
// ahblite controller between the memories and this cache.
logic [LOGWPL-1:0] WordCount;
genvar index;
generate
@ -452,93 +441,19 @@ module lsu
assign LocalLsuBusAdr = SelUncachedAdr ? LsuPAdrM : DCacheBusAdr ;
assign LsuBusAdr = ({{`PA_BITS-LOGWPL{1'b0}}, WordCount} << $clog2(`XLEN/8)) + LocalLsuBusAdr;
assign PreLsuBusHWDATA = ReadDataBlockSetsM[WordCount];
assign LsuBusHWDATA = SelUncachedAdr ? WriteDataM : PreLsuBusHWDATA; // *** why is this not FinalWriteDataM? which does not work.
generate
if (`XLEN == 32) assign LsuBusSize = SelUncachedAdr ? LsuFunct3M : 3'b010;
else assign LsuBusSize = SelUncachedAdr ? LsuFunct3M : 3'b011;
endgenerate;
assign WordCountFlag = (WordCount == WordCountThreshold[LOGWPL-1:0]);
assign CntEn = PreCntEn & LsuBusAck;
flopenr #(LOGWPL)
WordCountReg(.clk(clk),
.reset(reset | CntReset),
.en(CntEn),
.d(NextWordCount),
.q(WordCount));
assign NextWordCount = WordCount + 1'b1;
typedef enum {STATE_BUS_READY,
STATE_BUS_FETCH,
STATE_BUS_WRITE,
STATE_BUS_UNCACHED_WRITE,
STATE_BUS_UNCACHED_WRITE_DONE,
STATE_BUS_UNCACHED_READ,
STATE_BUS_UNCACHED_READ_DONE,
STATE_BUS_CPU_BUSY} busstatetype;
(* mark_debug = "true" *) busstatetype BusCurrState, BusNextState;
always_ff @(posedge clk)
if (reset) BusCurrState <= #1 STATE_BUS_READY;
else BusCurrState <= #1 BusNextState;
always_comb begin
BusNextState = STATE_BUS_READY;
case(BusCurrState)
STATE_BUS_READY: if(IgnoreRequest) BusNextState = STATE_BUS_READY;
else if(LsuRWM[0] & ~CacheableM) BusNextState = STATE_BUS_UNCACHED_WRITE;
else if(LsuRWM[1] & ~CacheableM) BusNextState = STATE_BUS_UNCACHED_READ;
else if(DCacheFetchLine) BusNextState = STATE_BUS_FETCH;
else if(DCacheWriteLine) BusNextState = STATE_BUS_WRITE;
STATE_BUS_UNCACHED_WRITE: if(LsuBusAck) BusNextState = STATE_BUS_UNCACHED_WRITE_DONE;
else BusNextState = STATE_BUS_UNCACHED_WRITE;
STATE_BUS_UNCACHED_READ: if(LsuBusAck) BusNextState = STATE_BUS_UNCACHED_READ_DONE;
else BusNextState = STATE_BUS_UNCACHED_READ;
STATE_BUS_UNCACHED_WRITE_DONE: if(CPUBusy) BusNextState = STATE_BUS_CPU_BUSY;
else BusNextState = STATE_BUS_READY;
STATE_BUS_UNCACHED_READ_DONE: if(CPUBusy) BusNextState = STATE_BUS_CPU_BUSY;
else BusNextState = STATE_BUS_READY;
STATE_BUS_CPU_BUSY: if(CPUBusy) BusNextState = STATE_BUS_CPU_BUSY;
else BusNextState = STATE_BUS_READY;
STATE_BUS_FETCH: if (WordCountFlag & LsuBusAck) BusNextState = STATE_BUS_READY;
else BusNextState = STATE_BUS_FETCH;
STATE_BUS_WRITE: if(WordCountFlag & LsuBusAck) BusNextState = STATE_BUS_READY;
else BusNextState = STATE_BUS_WRITE;
endcase
end
assign CntReset = BusCurrState == STATE_BUS_READY;
assign BusStall = (BusCurrState == STATE_BUS_READY & ~IgnoreRequest & ((~CacheableM & (|LsuRWM)) | DCacheFetchLine | DCacheWriteLine)) |
(BusCurrState == STATE_BUS_UNCACHED_WRITE) |
(BusCurrState == STATE_BUS_UNCACHED_READ) |
(BusCurrState == STATE_BUS_FETCH) |
(BusCurrState == STATE_BUS_WRITE);
assign PreCntEn = BusCurrState == STATE_BUS_FETCH | BusCurrState == STATE_BUS_WRITE;
assign UnCachedLsuBusWrite = (BusCurrState == STATE_BUS_READY & ~CacheableM & (LsuRWM[0])) |
(BusCurrState == STATE_BUS_UNCACHED_WRITE);
assign LsuBusWrite = UnCachedLsuBusWrite | (BusCurrState == STATE_BUS_WRITE);
assign UnCachedLsuBusRead = (BusCurrState == STATE_BUS_READY & ~CacheableM & (|LsuRWM[1])) |
(BusCurrState == STATE_BUS_UNCACHED_READ);
assign LsuBusRead = UnCachedLsuBusRead | (BusCurrState == STATE_BUS_FETCH);
assign DCacheBusAck = (BusCurrState == STATE_BUS_FETCH & WordCountFlag & LsuBusAck) |
(BusCurrState == STATE_BUS_WRITE & WordCountFlag & LsuBusAck);
assign BusCommittedM = BusCurrState != STATE_BUS_READY;
assign SelUncachedAdr = (BusCurrState == STATE_BUS_READY & (|LsuRWM & ~CacheableM)) |
(BusCurrState == STATE_BUS_UNCACHED_READ |
BusCurrState == STATE_BUS_UNCACHED_READ_DONE |
BusCurrState == STATE_BUS_UNCACHED_WRITE |
BusCurrState == STATE_BUS_UNCACHED_WRITE_DONE);
busfsm #(WordCountThreshold, LOGWPL)
busfsm(.clk, .reset, .IgnoreRequest, .LsuRWM, .DCacheFetchLine, .DCacheWriteLine,
.LsuBusAck, .CPUBusy, .CacheableM, .BusStall, .LsuBusWrite, .LsuBusRead,
.DCacheBusAck, .BusCommittedM, .SelUncachedAdr, .WordCount);
endmodule