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Removed the CMO_WRITEBACK state from the cache and unused signals.

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This commit is contained in:
Rose Thompson 2023-11-20 20:52:11 -06:00
parent 667fe035c0
commit 52ac07ce8d
3 changed files with 14 additions and 28 deletions
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5
src/cache/cache.sv vendored
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@ -102,7 +102,6 @@ module cache import cvw::*; #(parameter cvw_t P,
logic [LINELEN/8-1:0] LineByteMask;
logic [$clog2(LINELEN/8) - $clog2(MUXINTERVAL/8) - 1:0] WordOffsetAddr;
logic ZeroCacheLine;
logic CMOZeroHit;
logic [LINELEN-1:0] PreLineWriteData;
genvar index;
@ -121,7 +120,7 @@ module cache import cvw::*; #(parameter cvw_t P,
// Array of cache ways, along with victim, hit, dirty, and read merging logic
cacheway #(P, PA_BITS, XLEN, NUMLINES, LINELEN, TAGLEN, OFFSETLEN, SETLEN, READ_ONLY_CACHE) CacheWays[NUMWAYS-1:0](
.clk, .reset, .CacheEn, .CMOp, .CacheSet, .PAdr, .LineWriteData, .LineByteMask, .SelWay,
.SetValid, .ClearValid, .SetDirty, .ClearDirty, .CMOZeroHit, .SelWriteback, .SelCMOWriteback, .VictimWay,
.SetValid, .ClearValid, .SetDirty, .ClearDirty, .SelWriteback, .SelCMOWriteback, .VictimWay,
.FlushWay, .SelFlush, .ReadDataLineWay, .HitWay, .ValidWay, .DirtyWay, .TagWay, .FlushStage, .InvalidateCache);
// Select victim way for associative caches
@ -233,7 +232,7 @@ module cache import cvw::*; #(parameter cvw_t P,
.FlushStage, .CacheRW, .CacheAtomic, .Stall,
.CacheHit, .LineDirty, .CacheStall, .CacheCommitted,
.CacheMiss, .CacheAccess, .SelAdr, .SelWay,
.ClearDirty, .SetDirty, .SetValid, .ClearValid, .ZeroCacheLine, .CMOZeroHit, .SelWriteback, .SelCMOWriteback, .SelFlush,
.ClearDirty, .SetDirty, .SetValid, .ClearValid, .ZeroCacheLine, .SelWriteback, .SelCMOWriteback, .SelFlush,
.FlushAdrCntEn, .FlushWayCntEn, .FlushCntRst,
.FlushAdrFlag, .FlushWayFlag, .FlushCache, .SelFetchBuffer,
.InvalidateCache, .CMOp, .CacheEn, .LRUWriteEn);

36
src/cache/cachefsm.sv vendored
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@ -60,7 +60,6 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
output logic SetDirty, // Set the dirty bit in the selected way and set
output logic ClearDirty, // Clear the dirty bit in the selected way and set
output logic ZeroCacheLine, // Write zeros to all bytes of cacheline
output logic CMOZeroHit, // CMOZ hit
output logic SelWriteback, // Overrides cached tag check to select a specific way and set for writeback
output logic SelCMOWriteback, // Overrides cached tag check to select a specific way and set for writeback for both data and tag
output logic LRUWriteEn, // Update the LRU state
@ -89,10 +88,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_READ_HOLD, // required for back to back reads. structural hazard on writting SRAM
// flush cache
STATE_FLUSH,
STATE_FLUSH_WRITEBACK,
// CMO states
STATE_CMO_WRITEBACK,
STATE_CMO_DONE
STATE_FLUSH_WRITEBACK
} statetype;
statetype CurrState, NextState;
@ -125,8 +121,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_READY: if(InvalidateCache) NextState = STATE_READY; // exclusion-tag: dcache InvalidateCheck
else if(FlushCache & ~READ_ONLY_CACHE) NextState = STATE_FLUSH;
else if(AnyMiss & (READ_ONLY_CACHE | ~LineDirty)) NextState = STATE_FETCH; // exclusion-tag: icache FETCHStatement
else if(AnyMiss | CMOZeroEviction) NextState = STATE_WRITEBACK; // exclusion-tag: icache WRITEBACKStatement
else if(CMOWritebackHit) NextState = STATE_CMO_WRITEBACK;
else if(AnyMiss | CMOZeroEviction | CMOWritebackHit) NextState = STATE_WRITEBACK; // exclusion-tag: icache WRITEBACKStatement
else NextState = STATE_READY;
STATE_FETCH: if(CacheBusAck) NextState = STATE_WRITE_LINE;
else if(CacheBusAck) NextState = STATE_READY;
@ -135,7 +130,8 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_READ_HOLD: if(Stall) NextState = STATE_READ_HOLD;
else NextState = STATE_READY;
// exclusion-tag-start: icache case
STATE_WRITEBACK: if(CacheBusAck & ~CMOp[3]) NextState = STATE_FETCH;
STATE_WRITEBACK: if (CacheBusAck & (CMOp[1] | CMOp[2])) NextState = STATE_READ_HOLD;
else if(CacheBusAck & ~CMOp[3]) NextState = STATE_FETCH;
else if(CacheBusAck) NextState = STATE_READ_HOLD;
else NextState = STATE_WRITEBACK;
// eviction needs a delay as the bus fsm does not correctly handle sending the write command at the same time as getting back the bus ack.
@ -145,32 +141,25 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_FLUSH_WRITEBACK: if(CacheBusAck & ~FlushFlag) NextState = STATE_FLUSH;
else if(CacheBusAck) NextState = STATE_READ_HOLD;
else NextState = STATE_FLUSH_WRITEBACK;
STATE_CMO_WRITEBACK: if(CacheBusAck & (CMOp[1] | CMOp[2])) NextState = STATE_READ_HOLD;
else NextState = STATE_CMO_WRITEBACK;
STATE_CMO_DONE: if(Stall) NextState = STATE_CMO_DONE;
else NextState = STATE_READY;
// exclusion-tag-end: icache case
default: NextState = STATE_READY;
endcase
end
// com back to CPU
assign CacheCommitted = (CurrState != STATE_READY) & ~(READ_ONLY_CACHE & (CurrState == STATE_READ_HOLD | CurrState == STATE_CMO_DONE));
assign CacheCommitted = (CurrState != STATE_READY) & ~(READ_ONLY_CACHE & (CurrState == STATE_READ_HOLD));
assign CacheStall = (CurrState == STATE_READY & (FlushCache | AnyMiss | CMOWritebackHit | CMOZeroEviction)) | // exclusion-tag: icache StallStates
(CurrState == STATE_FETCH) |
(CurrState == STATE_WRITEBACK) |
(CurrState == STATE_WRITE_LINE) | // this cycle writes the sram, must keep stalling so the next cycle can read the next hit/miss unless its a write.
(CurrState == STATE_FLUSH) |
(CurrState == STATE_FLUSH_WRITEBACK) |
(CurrState == STATE_CMO_WRITEBACK);
(CurrState == STATE_FLUSH_WRITEBACK);
// write enables internal to cache
assign CMOZeroHit = CurrState == STATE_READY & CMOp[3] & CacheHit ;
assign SetValid = CurrState == STATE_WRITE_LINE |
(P.ZICBOZ_SUPPORTED & CurrState == STATE_READY & CMOZeroNoEviction) |
(P.ZICBOZ_SUPPORTED & CurrState == STATE_WRITEBACK & CacheBusAck & CMOp[3]);
assign ClearValid = P.ZICBOM_SUPPORTED & ((CurrState == STATE_READY & CMOp[0] & CacheHit) |
(CurrState == STATE_CMO_WRITEBACK & CMOp[2] & CacheBusAck));
(CurrState == STATE_WRITEBACK & CMOp[2] & CacheBusAck));
// coverage off -item e 1 -fecexprrow 8
assign LRUWriteEn = (((CurrState == STATE_READY & (AnyHit | CMOZeroNoEviction)) |
(CurrState == STATE_WRITE_LINE)) & ~FlushStage) |
@ -182,7 +171,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
assign ClearDirty = (CurrState == STATE_WRITE_LINE & ~(CacheRW[0])) | // exclusion-tag: icache ClearDirty
(CurrState == STATE_FLUSH & LineDirty) | // This is wrong in a multicore snoop cache protocal. Dirty must be cleared concurrently and atomically with writeback. For single core cannot clear after writeback on bus ack and change flushadr. Clears the wrong set.
// Flush and eviction controls
(P.ZICBOM_SUPPORTED & CurrState == STATE_CMO_WRITEBACK & (CMOp[1] | CMOp[2]) & CacheBusAck);
(P.ZICBOM_SUPPORTED & CurrState == STATE_WRITEBACK & (CMOp[1] | CMOp[2]) & CacheBusAck);
assign SelWay = SelWriteback | (CurrState == STATE_WRITE_LINE) |
// This is almost the same as setvalid, but on cachehit we don't want to select
// the nonhit way, but instead want to force this to zero
@ -190,9 +179,9 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
(P.ZICBOZ_SUPPORTED & CurrState == STATE_WRITEBACK & CacheBusAck & CMOp[3]);
assign ZeroCacheLine = P.ZICBOZ_SUPPORTED & ((CurrState == STATE_READY & CMOZeroNoEviction) |
(CurrState == STATE_WRITEBACK & (CMOp[3] & CacheBusAck)));
assign SelWriteback = (CurrState == STATE_WRITEBACK & ~CacheBusAck) |
assign SelWriteback = (CurrState == STATE_WRITEBACK & ~CacheBusAck & ~(CMOp[1] | CMOp[2])) |
(CurrState == STATE_READY & AnyMiss & LineDirty);
assign SelCMOWriteback = CurrState == STATE_CMO_WRITEBACK;
assign SelCMOWriteback = CurrState == STATE_WRITEBACK & (CMOp[1] | CMOp[2]);
assign SelFlush = (CurrState == STATE_READY & FlushCache) |
(CurrState == STATE_FLUSH) |
@ -209,17 +198,16 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
// Bus interface controls
assign CacheBusRW[1] = (CurrState == STATE_READY & AnyMiss & ~LineDirty) | // exclusion-tag: icache CacheBusRCauses
(CurrState == STATE_FETCH & ~CacheBusAck) |
(CurrState == STATE_WRITEBACK & CacheBusAck & ~CMOp[3]);
(CurrState == STATE_WRITEBACK & CacheBusAck & ~(|CMOp));
assign CacheBusRW[0] = (CurrState == STATE_READY & AnyMiss & LineDirty) | // exclusion-tag: icache CacheBusW
(CurrState == STATE_WRITEBACK & ~CacheBusAck) |
(CurrState == STATE_FLUSH_WRITEBACK & ~CacheBusAck) |
(P.ZICBOM_SUPPORTED & CurrState == STATE_CMO_WRITEBACK & (CMOp[1] | CMOp[2]) & ~CacheBusAck);
(P.ZICBOM_SUPPORTED & CurrState == STATE_WRITEBACK & (CMOp[1] | CMOp[2]) & ~CacheBusAck);
assign SelAdr = (CurrState == STATE_READY & (CacheRW[0] | AnyMiss | (|CMOp))) | // exclusion-tag: icache SelAdrCauses // changes if store delay hazard removed
(CurrState == STATE_FETCH) |
(CurrState == STATE_WRITEBACK) |
(CurrState == STATE_WRITE_LINE) |
(CurrState == STATE_CMO_WRITEBACK) |
resetDelay;
assign SelFetchBuffer = CurrState == STATE_WRITE_LINE | CurrState == STATE_READ_HOLD;
assign CacheEn = (~Stall | FlushCache | AnyMiss) | (CurrState != STATE_READY) | reset | InvalidateCache; // exclusion-tag: dcache CacheEn

1
src/cache/cacheway.sv vendored
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@ -42,7 +42,6 @@ module cacheway import cvw::*; #(parameter cvw_t P,
input logic ClearValid, // Clear the valid bit in the selected way and set
input logic SetDirty, // Set the dirty bit in the selected way and set
input logic SelWay, // Controls which way to select a way data and tag, 00 = hitway, 10 = victimway, 11 = flushway
input logic CMOZeroHit, // Write zeros to all bytes of a cache line
input logic ClearDirty, // Clear the dirty bit in the selected way and set
input logic SelWriteback, // Overrides cached tag check to select a specific way and set for writeback
input logic SelCMOWriteback,// Overrides cached tag check to select a specific way and set for writeback for both data and tag