diff --git a/pipelined/src/cache/AHBBuscachefsm.sv b/pipelined/src/cache/AHBBuscachefsm.sv index 7645ab1df..b5b5eccc7 100644 --- a/pipelined/src/cache/AHBBuscachefsm.sv +++ b/pipelined/src/cache/AHBBuscachefsm.sv @@ -64,7 +64,8 @@ module AHBBuscachefsm #(parameter integer WordCountThreshold, STATE_CAPTURE, STATE_DELAY, STATE_CPU_BUSY, - STATE_CACHE_ACCESS} busstatetype; + STATE_CACHE_FETCH, + STATE_CACHE_EVICT} busstatetype; typedef enum logic [1:0] {AHB_IDLE = 2'b00, AHB_BUSY = 2'b01, AHB_NONSEQ = 2'b10, AHB_SEQ = 2'b11} ahbtranstype; @@ -75,7 +76,6 @@ module AHBBuscachefsm #(parameter integer WordCountThreshold, logic WordCountFlag; logic [2:0] LocalBurstType; logic WordCntReset; - logic [1:0] RWDelay, CacheRWDelay; // Used to send address for address stage of AHB. @@ -96,15 +96,10 @@ module AHBBuscachefsm #(parameter integer WordCountThreshold, assign NextWordCount = WordCount + 1'b1; assign WordCountFlag = (WordCountDelayed == WordCountThreshold[LOGWPL-1:0] ); // Detect when we are waiting on the final access. - assign WordCntEn = (BusNextState == STATE_CACHE_ACCESS & HREADY) | + assign WordCntEn = ((BusNextState == STATE_CACHE_EVICT | BusNextState == STATE_CACHE_FETCH) & HREADY) | (BusNextState == STATE_READY & |CacheRW & HREADY); assign WordCntReset = BusNextState == STATE_READY; - // replace with fsm with two more states. - flopenr #(2) RWReg(HCLK, ~HRESETn, 1'b1, RW, RWDelay); - flopenr #(2) CacheRWReg(HCLK, ~HRESETn, 1'b1, CacheRW, CacheRWDelay); - - always_ff @(posedge HCLK) if (~HRESETn) BusCurrState <= #1 STATE_READY; else BusCurrState <= #1 BusNextState; @@ -112,7 +107,8 @@ module AHBBuscachefsm #(parameter integer WordCountThreshold, always_comb begin case(BusCurrState) STATE_READY: if(HREADY & |RW) BusNextState = STATE_CAPTURE; - else if (HREADY & |CacheRW) BusNextState = STATE_CACHE_ACCESS; + else if (HREADY & CacheRW[0]) BusNextState = STATE_CACHE_EVICT; + else if (HREADY & CacheRW[1]) BusNextState = STATE_CACHE_FETCH; else BusNextState = STATE_READY; STATE_CAPTURE: if(HREADY) BusNextState = STATE_DELAY; else BusNextState = STATE_CAPTURE; @@ -120,26 +116,29 @@ module AHBBuscachefsm #(parameter integer WordCountThreshold, else BusNextState = STATE_READY; STATE_CPU_BUSY: if(CPUBusy) BusNextState = STATE_CPU_BUSY; else BusNextState = STATE_READY; - STATE_CACHE_ACCESS: if(HREADY & WordCountFlag) BusNextState = STATE_READY; - else BusNextState = STATE_CACHE_ACCESS; + STATE_CACHE_FETCH: if(HREADY & WordCountFlag) BusNextState = STATE_READY; + else BusNextState = STATE_CACHE_FETCH; + STATE_CACHE_EVICT: if(HREADY & WordCountFlag) BusNextState = STATE_READY; + else BusNextState = STATE_CACHE_EVICT; default: BusNextState = STATE_READY; endcase end assign BusStall = (BusCurrState == STATE_READY & (|RW | |CacheRW)) | (BusCurrState == STATE_CAPTURE) | - (BusCurrState == STATE_CACHE_ACCESS); + (BusCurrState == STATE_CACHE_FETCH) | + (BusCurrState == STATE_CACHE_EVICT); assign BusCommitted = BusCurrState != STATE_READY; // *** might not be correct assign HTRANS = (BusCurrState == STATE_READY & HREADY & (|RW | |CacheRW)) | (BusCurrState == STATE_CAPTURE & ~HREADY) | - (BusCurrState == STATE_CACHE_ACCESS & ~HREADY & ~|WordCount) ? AHB_NONSEQ : - (BusCurrState == STATE_CACHE_ACCESS & |WordCount) ? AHB_SEQ : AHB_IDLE; + ((BusCurrState == STATE_CACHE_FETCH | BusCurrState == STATE_CACHE_EVICT) & ~HREADY & ~|WordCount) ? AHB_NONSEQ : + ((BusCurrState == STATE_CACHE_FETCH | BusCurrState == STATE_CACHE_EVICT) & |WordCount) ? AHB_SEQ : AHB_IDLE; assign HWRITE = (BusCurrState == STATE_READY & (RW[0] | CacheRW[0])) | // *** might not be necessary, maybe just RW[0] - (BusCurrState == STATE_CACHE_ACCESS & CacheRW[0]); - assign CaptureEn = (BusCurrState == STATE_CAPTURE & RWDelay[1]) | (BusCurrState == STATE_CACHE_ACCESS & HREADY & CacheRWDelay[1]); + (BusCurrState == STATE_CACHE_EVICT); + assign CaptureEn = (BusCurrState == STATE_CAPTURE & RW[1]) | (BusCurrState == STATE_CACHE_FETCH & HREADY); assign HBURST = (|CacheRW) ? LocalBurstType : 3'b0; // Don't want to use burst when doing an Uncached Access. always_comb begin @@ -156,10 +155,10 @@ module AHBBuscachefsm #(parameter integer WordCountThreshold, (BusCurrState == STATE_CAPTURE) | (BusCurrState == STATE_DELAY); - assign CacheBusAck = (BusCurrState == STATE_CACHE_ACCESS & HREADY & WordCountFlag); + assign CacheBusAck = ((BusCurrState == STATE_CACHE_FETCH | BusCurrState == STATE_CACHE_EVICT) & HREADY & WordCountFlag); assign SelBusWord = (BusCurrState == STATE_READY & (RW[0] | CacheRW[0])) | (BusCurrState == STATE_CAPTURE & RW[0]) | - (BusCurrState == STATE_CACHE_ACCESS & CacheRW[0]); + (BusCurrState == STATE_CACHE_EVICT); endmodule