diff --git a/pipelined/src/ebu/ahbmultimanager.sv b/pipelined/src/ebu/ahbmultimanager.sv index e6eeabdb6..c3085af86 100644 --- a/pipelined/src/ebu/ahbmultimanager.sv +++ b/pipelined/src/ebu/ahbmultimanager.sv @@ -79,11 +79,12 @@ module ahbmultimanager logic [1:0] save, restore, dis, sel; logic both; - logic DoArbitration; logic [`PA_BITS-1:0] IFUHADDRSave, IFUHADDRRestore; logic [1:0] IFUHTRANSSave, IFUHTRANSRestore; logic [2:0] IFUHBURSTSave, IFUHBURSTRestore; + logic [2:0] IFUHSIZERestore; + logic IFUHWRITERestore; logic [`PA_BITS-1:0] LSUHADDRSave, LSUHADDRRestore; logic [1:0] LSUHTRANSSave, LSUHTRANSRestore; @@ -94,9 +95,9 @@ module ahbmultimanager logic IFUReq, LSUReq; logic IFUActive, LSUActive; - logic WordCntEn; - logic [4-1:0] NextWordCount, WordCount, WordCountDelayed; - logic WordCountFlag; + logic BeatCntEn; + logic [4-1:0] NextBeatCount, BeatCount, BeatCountDelayed; + logic FinalBeat; logic [2:0] LocalBurstType; logic CntReset; logic [3:0] Threshold; @@ -109,32 +110,18 @@ module ahbmultimanager // inputs. Abritration scheme is LSU always goes first. // input stage IFU - flopenr #(3+2+`PA_BITS) IFUSaveReg(HCLK, ~HRESETn, save[0], - {IFUHBURST, IFUHTRANS, IFUHADDR}, - {IFUHBURSTSave, IFUHTRANSSave, IFUHADDRSave}); - mux2 #(3+2+`PA_BITS) IFURestorMux({IFUHBURST, IFUHTRANS, IFUHADDR}, - {IFUHBURSTSave, IFUHTRANSSave, IFUHADDRSave}, - restore[0], - {IFUHBURSTRestore, IFUHTRANSRestore, IFUHADDRRestore}); - assign IFUReq = IFUHTRANSRestore != 2'b00; - - assign IFUHREADY = HREADY & ~dis[0]; - assign IFUActive = IFUReq & IFUHREADY; + managerinputstage IFUInput(.HCLK, .HRESETn, .Save(save[0]), .Restore(restore[0]), .Disable(dis[0]), + .Request(IFUReq), .Active(IFUActive), + .HWRITEin(1'b0), .HSIZEin(3'b010), .HBURSTin(IFUHBURST), .HTRANSin(IFUHTRANS), .HADDRin(IFUHADDR), + .HWRITERestore(IFUHWRITERestore), .HSIZERestore(IFUHSIZERestore), .HBURSTRestore(IFUHBURSTRestore), .HREADYRestore(IFUHREADY), + .HTRANSRestore(IFUHTRANSRestore), .HADDRRestore(IFUHADDRRestore), .HREADYin(HREADY)); // input stage LSU - flopenr #(1+3+3+2+`PA_BITS) LSUSaveReg(HCLK, ~HRESETn, save[1], - {LSUHWRITE, LSUHSIZE, LSUHBURST, LSUHTRANS, LSUHADDR}, - {LSUHWRITESave, LSUHSIZESave, LSUHBURSTSave, LSUHTRANSSave, LSUHADDRSave}); - mux2 #(1+3+3+2+`PA_BITS) LSURestorMux({LSUHWRITE, LSUHSIZE, LSUHBURST, LSUHTRANS, LSUHADDR}, - {LSUHWRITESave, LSUHSIZESave, LSUHBURSTSave, LSUHTRANSSave, LSUHADDRSave}, - restore[1], - {LSUHWRITERestore, LSUHSIZERestore, LSUHBURSTRestore, LSUHTRANSRestore, LSUHADDRRestore}); - - assign LSUReq = LSUHTRANSRestore != 2'b00; - assign LSUHREADY = HREADY & ~dis[1]; - assign LSUActive = LSUReq & LSUHREADY; - - assign both = LSUActive & IFUActive; + managerinputstage LSUInput(.HCLK, .HRESETn, .Save(save[1]), .Restore(restore[1]), .Disable(dis[1]), + .Request(LSUReq), .Active(LSUActive), + .HWRITEin(LSUHWRITE), .HSIZEin(LSUHSIZE), .HBURSTin(LSUHBURST), .HTRANSin(LSUHTRANS), .HADDRin(LSUHADDR), .HREADYRestore(LSUHREADY), + .HWRITERestore(LSUHWRITERestore), .HSIZERestore(LSUHSIZERestore), .HBURSTRestore(LSUHBURSTRestore), + .HTRANSRestore(LSUHTRANSRestore), .HADDRRestore(LSUHADDRRestore), .HREADYin(HREADY)); // output mux //*** rewrite for general number of managers. assign HADDR = sel[1] ? LSUHADDRRestore : sel[0] ? IFUHADDRRestore : '0; @@ -145,64 +132,50 @@ module ahbmultimanager assign HMASTLOCK = 0; // no locking supported assign HWRITE = sel[1] ? LSUHWRITERestore : sel[0] ? 1'b0 : '0; - // basic arb always selects LSU when both - assign save[0] = CurrState == IDLE & both; - assign restore[0] = CurrState == ARBITRATE; - assign dis[0] = CurrState == ARBITRATE; - assign sel[0] = (NextState == ARBITRATE) ? 1'b0 : IFUReq; + // data phase muxing. This would be a mux if IFU wrote data. + assign HWDATA = LSUHWDATA; + assign HWSTRB = LSUHWSTRB; + // HRDATA is sent to all managers at the core level. - // - assign save[1] = 1'b0; - assign restore[1] = 1'b0; - assign dis[1] = 1'b0; - assign sel[1] = NextState == ARBITRATE ? 1'b1: LSUReq; - - - - // Bus State FSM - // Data accesses have priority over instructions. However, if a data access comes - // while an cache line read is occuring, the line read finishes before - // the data access can take place. - + // FSM decides if arbitration needed. Arbitration is held until the last beat of + // a burst is completed. + assign both = LSUActive & IFUActive; flopenl #(.TYPE(statetype)) busreg(HCLK, ~HRESETn, 1'b1, NextState, IDLE, CurrState); always_comb case (CurrState) - IDLE: if (both) NextState = ARBITRATE; - else NextState = IDLE; - ARBITRATE: if (HREADY & WordCountFlag) NextState = IDLE; - else NextState = ARBITRATE; - default: NextState = IDLE; - endcase // case (CurrState) - - assign DoArbitration = CurrState == ARBITRATE; - - assign HWDATA = LSUHWDATA; - assign HWSTRB = LSUHWSTRB; + IDLE: if (both) NextState = ARBITRATE; + else NextState = IDLE; + ARBITRATE: if (HREADY & FinalBeat) NextState = IDLE; + else NextState = ARBITRATE; + default: NextState = IDLE; + endcase + // Manager needs to count beats. flopenr #(4) - WordCountReg(.clk(HCLK), + BeatCountReg(.clk(HCLK), .reset(~HRESETn | CntReset), - .en(WordCntEn), - .d(NextWordCount), - .q(WordCount)); + .en(BeatCntEn), + .d(NextBeatCount), + .q(BeatCount)); // Used to store data from data phase of AHB. flopenr #(4) - WordCountDelayedReg(.clk(HCLK), + BeatCountDelayedReg(.clk(HCLK), .reset(~HRESETn | CntReset), - .en(WordCntEn), - .d(WordCount), - .q(WordCountDelayed)); - assign NextWordCount = WordCount + 1'b1; + .en(BeatCntEn), + .d(BeatCount), + .q(BeatCountDelayed)); + assign NextBeatCount = BeatCount + 1'b1; assign CntReset = NextState == IDLE; - assign WordCountFlag = (WordCountDelayed == Threshold); // Detect when we are waiting on the final access. - assign WordCntEn = (NextState == ARBITRATE & HREADY); + assign FinalBeat = (BeatCountDelayed == Threshold); // Detect when we are waiting on the final access. + assign BeatCntEn = (NextState == ARBITRATE & HREADY); logic [2:0] HBURSTD; flopenr #(3) HBURSTReg(.clk(HCLK), .reset(~HRESETn), .en(HTRANS == 2'b10), .d(HBURST), .q(HBURSTD)); + // unlike the bus fsm in lsu/ifu, we need to derive the number of beats from HBURST. always_comb begin case(HBURSTD) 0: Threshold = 4'b0000; @@ -213,5 +186,17 @@ module ahbmultimanager endcase end + // basic arb always selects LSU when both + // replace this block for more sophisticated arbitration. + // Manager 0 (IFU) + assign save[0] = CurrState == IDLE & both; + assign restore[0] = CurrState == ARBITRATE; + assign dis[0] = CurrState == ARBITRATE; + assign sel[0] = (NextState == ARBITRATE) ? 1'b0 : IFUReq; + // Manager 1 (LSU) + assign save[1] = 1'b0; + assign restore[1] = 1'b0; + assign dis[1] = 1'b0; + assign sel[1] = NextState == ARBITRATE ? 1'b1: LSUReq; endmodule diff --git a/pipelined/src/ebu/managerinputstage.sv b/pipelined/src/ebu/managerinputstage.sv new file mode 100644 index 000000000..9ea587a73 --- /dev/null +++ b/pipelined/src/ebu/managerinputstage.sv @@ -0,0 +1,81 @@ +/////////////////////////////////////////// +// manager input stage +// +// Written: Ross Thompson August 31, 2022 +// ross1728@gmail.com +// Modified: +// +// Purpose: AHB multi manager interface to merge LSU and IFU controls. +// See ARM_HIH0033A_AMBA_AHB-Lite_SPEC 1.0 +// Arbitrates requests from instruction and data streams +// Connects core to peripherals and I/O pins on SOC +// Bus width presently matches XLEN +// Anticipate replacing this with an AXI bus interface to communicate with FPGA DRAM/Flash controllers +// +// A component of the Wally configurable RISC-V project. +// +// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University +// +// MIT LICENSE +// 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 managerinputstage + (input logic HCLK, + input logic HRESETn, + input logic Save, Restore, Disable, + output logic Request, Active, + // manager input + input logic HWRITEin, + input logic [2:0] HSIZEin, + input logic [2:0] HBURSTin, + input logic [1:0] HTRANSin, + input logic [`PA_BITS-1:0] HADDRin, + output logic HREADYRestore, + // manager output + output logic HWRITERestore, + output logic [2:0] HSIZERestore, + output logic [2:0] HBURSTRestore, + output logic [1:0] HTRANSRestore, + output logic [`PA_BITS-1:0] HADDRRestore, + input logic HREADYin + ); + + logic HWRITESave; + logic [2:0] HSIZESave; + logic [2:0] HBURSTSave; + logic [1:0] HTRANSSave; + logic [`PA_BITS-1:0] HADDRSave; + + flopenr #(1+3+3+2+`PA_BITS) SaveReg(HCLK, ~HRESETn, Save, + {HWRITEin, HSIZEin, HBURSTin, HTRANSin, HADDRin}, + {HWRITESave, HSIZESave, HBURSTSave, HTRANSSave, HADDRSave}); + mux2 #(1+3+3+2+`PA_BITS) RestorMux({HWRITEin, HSIZEin, HBURSTin, HTRANSin, HADDRin}, + {HWRITESave, HSIZESave, HBURSTSave, HTRANSSave, HADDRSave}, + Restore, + {HWRITERestore, HSIZERestore, HBURSTRestore, HTRANSRestore, HADDRRestore}); + + assign Request = HTRANSRestore != 2'b00; + assign HREADYRestore = HREADYin & ~Disable; + assign Active = Request & HREADYRestore; + +endmodule + + +