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Simplified logic around IgnoreRequest and HPTWFaultM.

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This commit is contained in:
Rose Thompson 2024-10-11 14:41:52 -05:00
parent fe5f342d2f
commit 7a92d41ef5
2 changed files with 10 additions and 15 deletions
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18
src/lsu/lsu.sv
View File

@ -110,7 +110,6 @@ module lsu import cvw::*; #(parameter cvw_t P) (
logic GatedStallW; // Hazard unit StallW gated when SelHPTW = 1
logic BusStall; // Bus interface busy with multicycle operation
logic LSUBusStallM; // Bus interface busy with multicycle operation masked by IgnoreRequestTLB
logic HPTWStall; // HPTW busy with multicycle operation
logic DCacheBusStallM; // Cache or bus stall
@ -309,8 +308,6 @@ module lsu import cvw::*; #(parameter cvw_t P) (
logic CacheableOrFlushCacheM; // Memory address is cacheable or operation is a cache flush
logic [1:0] CacheRWM; // Cache read (10), write (01), AMO (11)
logic FlushDCache; // Suppress d cache flush if there is an ITLB miss.
logic CacheStall;
logic [1:0] CacheBusRWTemp;
logic BusCMOZero;
logic [3:0] CacheCMOpM;
logic BusAtomic;
@ -336,15 +333,12 @@ module lsu import cvw::*; #(parameter cvw_t P) (
.FlushCache(FlushDCache), .NextSet(IEUAdrExtE[11:0]), .PAdr(PAdrM),
.ByteMask(ByteMaskSpillM), .BeatCount(BeatCount[AHBWLOGBWPL-1:AHBWLOGBWPL-LLENLOGBWPL]),
.WriteData(LSUWriteDataSpillM), .SelHPTW,
.CacheStall, .CacheMiss(DCacheMiss), .CacheAccess(DCacheAccess),
.CacheStall(DCacheStallM), .CacheMiss(DCacheMiss), .CacheAccess(DCacheAccess),
.CacheCommitted(DCacheCommittedM),
.CacheBusAdr(DCacheBusAdr), .ReadDataWord(DCacheReadDataWordM),
.FetchBuffer, .CacheBusRW(CacheBusRWTemp),
.FetchBuffer, .CacheBusRW(CacheBusRW),
.CacheBusAck(DCacheBusAck), .InvalidateCache(1'b0), .CMOpM(CacheCMOpM));
assign DCacheStallM = CacheStall;
assign CacheBusRW = CacheBusRWTemp;
ahbcacheinterface #(.P(P), .BEATSPERLINE(BEATSPERLINE), .AHBWLOGBWPL(AHBWLOGBWPL), .LINELEN(LINELEN), .LLENPOVERAHBW(LLENPOVERAHBW), .READ_ONLY_CACHE(0)) ahbcacheinterface(
.HCLK(clk), .HRESETn(~reset), .Flush(IgnoreRequest),
.HRDATA, .HWDATA(LSUHWDATA), .HWSTRB(LSUHWSTRB),
@ -353,7 +347,7 @@ module lsu import cvw::*; #(parameter cvw_t P) (
.Funct3(LSUFunct3M), .HADDR(LSUHADDR), .CacheBusAdr(DCacheBusAdr), .CacheBusRW, .BusAtomic, .BusCMOZero, .CacheableOrFlushCacheM,
.CacheBusAck(DCacheBusAck), .FetchBuffer, .PAdr(PAdrM),
.Cacheable(CacheableOrFlushCacheM), .BusRW, .Stall(GatedStallW),
.BusStall, .BusCommitted(BusCommittedM));
.BusStall(LSUBusStallM), .BusCommitted(BusCommittedM));
mux3 #(P.LLEN) UnCachedDataMux(.d0(DCacheReadDataWordSpillM), .d1({LLENPOVERAHBW{FetchBuffer[P.XLEN-1:0]}}),
.d2({{P.LLEN-P.XLEN{1'b0}}, DTIMReadDataWordM[P.XLEN-1:0]}),
@ -369,7 +363,7 @@ module lsu import cvw::*; #(parameter cvw_t P) (
ahbinterface #(P.XLEN, 1'b1) ahbinterface(.HCLK(clk), .HRESETn(~reset), .Flush(IgnoreRequest), .HREADY(LSUHREADY),
.HRDATA(HRDATA), .HTRANS(LSUHTRANS), .HWRITE(LSUHWRITE), .HWDATA(LSUHWDATA),
.HWSTRB(LSUHWSTRB), .BusRW, .BusAtomic(AtomicM[1]), .ByteMask(ByteMaskM[P.XLEN/8-1:0]), .WriteData(LSUWriteDataM[P.XLEN-1:0]),
.Stall(GatedStallW), .BusStall, .BusCommitted(BusCommittedM), .FetchBuffer(FetchBuffer));
.Stall(GatedStallW), .BusStall(LSUBusStallM), .BusCommitted(BusCommittedM), .FetchBuffer(FetchBuffer));
// Mux between the 2 sources of read data, 0: Bus, 1: DTIM
if(P.DTIM_SUPPORTED) mux2 #(P.XLEN) ReadDataMux2(FetchBuffer, DTIMReadDataWordM[P.XLEN-1:0], SelDTIM, ReadDataWordMuxM[P.XLEN-1:0]);
@ -381,12 +375,10 @@ module lsu import cvw::*; #(parameter cvw_t P) (
assign {LSUHWDATA, LSUHADDR, LSUHWRITE, LSUHSIZE, LSUHBURST, LSUHTRANS, LSUHWSTRB} = '0;
assign DCacheReadDataWordM = '0;
assign ReadDataWordMuxM = DTIMReadDataWordM;
assign {BusStall, BusCommittedM} = '0;
assign {LSUBusStallM, BusCommittedM} = '0;
assign {DCacheMiss, DCacheAccess} = '0;
assign {DCacheStallM, DCacheCommittedM} = '0;
end
assign LSUBusStallM = BusStall;
/////////////////////////////////////////////////////////////////////////////////////////////
// Atomic operations

7
src/mmu/hptw.sv
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@ -105,6 +105,7 @@ module hptw import cvw::*; #(parameter cvw_t P) (
logic TakeHPTWFault;
logic PBMTFaultM;
logic HPTWFaultM;
logic ResetPTE;
// map hptw access faults onto either the original LSU load/store fault or instruction access fault
assign LSUAccessFaultM = LSULoadAccessFaultM | LSUStoreAmoAccessFaultM;
@ -143,7 +144,7 @@ module hptw import cvw::*; #(parameter cvw_t P) (
// State flops
flopenr #(1) TLBMissMReg(clk, reset, StartWalk, DTLBMissOrUpdateDAM, DTLBWalk); // when walk begins, record whether it was for DTLB (or record 0 for ITLB)
assign PRegEn = HPTWRW[1] & ~DCacheBusStallM | UpdatePTE;
flopenr #(P.XLEN) PTEReg(clk, reset, PRegEn, NextPTE, PTE); // Capture page table entry from data cache
flopenr #(P.XLEN) PTEReg(clk, ResetPTE, PRegEn, NextPTE, PTE); // Capture page table entry from data cache
// Assign PTE descriptors common across all XLEN values
// For non-leaf PTEs, D, A, U bits are reserved and ignored. They do not cause faults while walking the page table
@ -300,7 +301,9 @@ module hptw import cvw::*; #(parameter cvw_t P) (
default: NextWalkerState = IDLE; // Should never be reached
endcase // case (WalkerState)
assign IgnoreRequestTLB = (WalkerState == IDLE & TLBMissOrUpdateDA) | (WalkerState != IDLE & HPTWFaultM); // If hptw request has pmp/a fault suppress bus access.
assign IgnoreRequestTLB = (WalkerState == IDLE & TLBMissOrUpdateDA) |
((WalkerState == L3_RD | WalkerState == L2_RD | WalkerState == L1_RD | WalkerState == L0_RD) & HPTWFaultM); // HPTWFaultM is hear because the hptw faults are delayed one cycle and we need to prevent the cache/bus from taking the operation. On the next cycle the CPU will trap.
assign ResetPTE = reset | (WalkerState == IDLE);
assign SelHPTW = WalkerState != IDLE;
assign HPTWStall = (WalkerState != IDLE & WalkerState != FAULT) | (WalkerState == IDLE & TLBMissOrUpdateDA);