cvw/src/debug/dm.sv
2024-06-11 22:42:30 -05:00

469 lines
18 KiB
Systemverilog

///////////////////////////////////////////
// dm.sv
//
// Written: matthew.n.otto@okstate.edu, james.stine@okstate.edu
// Created: 15 March 2024
//
// Purpose: Main debug module (dm) for Debug Specification
//
// A component of the CORE-V-WALLY configurable RISC-V project.
// https://github.com/openhwgroup/cvw
//
// Copyright (C) 2021-24 Harvey Mudd College & Oklahoma State University
//
// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
//
// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
// except in compliance with the License, or, at your option, the Apache License Version 2.0. You
// may obtain a copy of the License at
//
// https://solderpad.org/licenses/SHL-2.1/
//
// Unless required by applicable law or agreed to in writing, any work distributed under the
// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
// either express or implied. See the License for the specific language governing permissions
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////
module dm import cvw::*; #(parameter cvw_t P) (
input logic clk,
input logic rst,
// External JTAG signals
input logic tck,
input logic tdi,
input logic tms,
output logic tdo,
// Platform reset signal
output logic NdmReset,
// Core hazard signal
output logic DebugStall,
// Scan Chain
output logic DebugScanEn, // puts scannable flops into scan mode
input logic DebugScanIn, // (misc) scan chain data in
input logic GPRScanIn, // (GPR) scan chain data in
input logic FPRScanIn, // (FPR) scan chain data in
input logic CSRScanIn, // (CSR) scan chain data in
output logic DebugScanOut, // scan chain data out
output logic MiscSel, // selects general scan chain
output logic GPRSel, // selects GPR scan chain
output logic FPRSel, // selects FPR scan chain
output logic CSRSel, // selects CSR scan chain
output logic [11:0] RegAddr, // address for scanable regfiles (GPR, FPR, CSR)
output logic DebugCapture, // latches values into scan register before scanning out
output logic DebugRegUpdate // writes values from scan register after scanning in
);
`include "debug.vh"
// DMI Signals
logic ReqReady;
logic ReqValid;
logic [`ADDR_WIDTH-1:0] ReqAddress;
logic [31:0] ReqData;
logic [1:0] ReqOP;
logic RspReady;
logic RspValid;
logic [31:0] RspData;
logic [1:0] RspOP;
// JTAG ID for Wally:
// [31:27] = 1 (4 bits)
// ver [27:12] = 0x2A (42)
// JEDEC number [11:1] = 000_0000_0010 (Open HW Group)
// [0] set to 1
localparam JTAG_DEVICE_ID = 32'h1002_A005;
dtm #(`ADDR_WIDTH, JTAG_DEVICE_ID) dtm (.clk, .tck, .tdi, .tms, .tdo,
.ReqReady, .ReqValid, .ReqAddress, .ReqData, .ReqOP, .RspReady,
.RspValid, .RspData, .RspOP);
// Core control signals
logic HaltReq;
logic ResumeReq;
logic HaltOnReset;
logic Halted;
logic AckHaveReset;
hartcontrol hartcontrol(.clk, .rst(rst | ~DmActive), .NdmReset, .AckHaveReset, .HaltReq,
.ResumeReq, .HaltOnReset, .DebugStall, .Halted, .AllRunning, .AnyRunning,
.AllHalted, .AnyHalted, .AllResumeAck, .AnyResumeAck, .AllHaveReset, .AnyHaveReset);
enum logic [3:0] {INACTIVE, IDLE, ACK, R_DATA, W_DATA, DMSTATUS, W_DMCONTROL, R_DMCONTROL,
W_ABSTRACTCS, R_ABSTRACTCS, ABST_COMMAND, R_SYSBUSCS, READ_ZERO,
INVALID} State;
enum logic [1:0] {AC_IDLE, AC_UPDATE, AC_SCAN, AC_CAPTURE} AcState, NewAcState;
// AbsCmd internal state
logic AcWrite; // Abstract Command write state
logic [P.LLEN:0] ScanReg; // The part of the debug scan chain located within DM
logic [P.LLEN-1:0] ScanNext; // New ScanReg value
logic [P.LLEN-1:0] ARMask; // Masks which bits of the ScanReg get updated
logic [P.LLEN-1:0] PackedDataReg; // Combines DataX msg registers into a single LLEN wide register
logic [P.LLEN-1:0] MaskedScanReg; // Masks which bits of the ScanReg get written to DataX
logic [9:0] ShiftCount; // Position of the selected register on the debug scan chain
logic [9:0] ScanChainLen; // Total length of currently selected scan chain
logic [9:0] Cycle; // DM's current position in the scan chain
logic InvalidRegNo; // Requested RegNo is invalid
logic RegReadOnly; // Current RegNo points to a readonly register
logic GPRegNo; // Requested RegNo is a GPR
logic FPRegNo; // Requested RegNo is a FPR
logic CSRegNo; // Requested RegNo is a CSR
logic StoreScanChain; // Store current value of ScanReg into DataX
logic WriteMsgReg; // Write to DataX
logic WriteScanReg; // Insert data from DataX into ScanReg
logic [31:0] Data0Wr; // Muxed inputs to DataX regs
logic [31:0] Data1Wr; // Muxed inputs to DataX regs
logic [31:0] Data2Wr; // Muxed inputs to DataX regs
logic [31:0] Data3Wr; // Muxed inputs to DataX regs
// message registers
logic [31:0] Data0; // 0x04
logic [31:0] Data1; // 0x05
logic [31:0] Data2; // 0x06
logic [31:0] Data3; // 0x07
// debug module registers
logic [31:0] DMControl; // 0x10
logic [31:0] DMStatus; // 0x11
logic [31:0] AbstractCS; // 0x16
logic [31:0] SysBusCS; // 0x38
//// DM register fields
// DMControl
logic AckUnavail;
logic DmActive; // This bit is used to (de)activate the DM. Toggling acts as reset
// DMStatus
logic StickyUnavail;
logic ImpEBreak;
logic AllHaveReset;
logic AnyHaveReset;
logic AllResumeAck;
logic AnyResumeAck;
logic AllNonExistent; // TODO
logic AnyNonExistent;
logic AllUnavail; // TODO
logic AnyUnavail;
logic AllRunning;
logic AnyRunning;
logic AllHalted;
logic AnyHalted;
const logic Authenticated = 1;
logic AuthBusy;
const logic HasResetHaltReq = 1;
logic ConfStrPtrValid;
const logic [3:0] Version = 3; // DM Version
// AbstractCS
const logic [4:0] ProgBufSize = 0;
logic Busy;
const logic RelaxedPriv = 1;
logic [2:0] CmdErr;
const logic [3:0] DataCount = (P.LLEN/32);
// See spec 3.14.2
assign DMControl = {2'b0, 1'b0, 2'b0, 1'b0, 10'b0, 10'b0, 4'b0, NdmReset, DmActive};
// See spec 3.14.1
assign DMStatus = {7'b0, 1'b0, StickyUnavail, ImpEBreak, 2'b0,
AllHaveReset, AnyHaveReset, AllResumeAck, AnyResumeAck, AllNonExistent,
AnyNonExistent, AllUnavail, AnyUnavail, AllRunning, AnyRunning, AllHalted,
AnyHalted, Authenticated, AuthBusy, HasResetHaltReq, ConfStrPtrValid, Version};
assign AbstractCS = {3'b0, ProgBufSize, 11'b0, Busy, RelaxedPriv, CmdErr, 4'b0, DataCount};
assign SysBusCS = 32'h20000000; // SBVersion = 1
assign RspValid = (State == ACK);
assign ReqReady = (State != ACK);
always_ff @(posedge clk) begin
if (rst) begin
DmActive <= 0;
State <= INACTIVE;
end else begin
case (State)
INACTIVE : begin
// Reset Values
// TODO: one-line these
RspData <= 0;
HaltReq <= 0;
ResumeReq <= 0;
AckHaveReset <= 0;
HaltOnReset <= 0;
NdmReset <= 0;
StickyUnavail <= 0;
ImpEBreak <= 0;
AuthBusy <= 0;
ConfStrPtrValid <= 0;
CmdErr <= 0;
if (ReqValid) begin
if (ReqAddress == `DMCONTROL & ReqOP == `OP_WRITE & ReqData[`DMACTIVE]) begin
DmActive <= ReqData[`DMACTIVE];
RspOP <= `OP_SUCCESS;
end
State <= ACK; // acknowledge all Reqs even if they don't activate DM
end
end
ACK : begin
NewAcState <= AC_IDLE;
ResumeReq <= 0;
AckHaveReset <= 0;
if (~ReqValid)
State <= ~DmActive ? INACTIVE : IDLE;
end
IDLE : begin
if (ReqValid)
case ({ReqOP, ReqAddress}) inside
{`OP_WRITE,`DATA0} : State <= W_DATA;
{`OP_READ,`DATA0} : State <= R_DATA;
{`OP_WRITE,`DATA1} : State <= (P.LLEN >= 64) ? W_DATA : INVALID;
{`OP_READ,`DATA1} : State <= (P.LLEN >= 64) ? R_DATA : INVALID;
[{`OP_WRITE,`DATA2}:{`OP_WRITE,`DATA3}] : State <= (P.LLEN >= 128) ? W_DATA : INVALID;
[{`OP_READ,`DATA2}:{`OP_READ,`DATA3}] : State <= (P.LLEN >= 128) ? R_DATA : INVALID;
{`OP_WRITE,`DMCONTROL} : State <= W_DMCONTROL;
{`OP_READ,`DMCONTROL} : State <= R_DMCONTROL;
{`OP_READ,`DMSTATUS} : State <= DMSTATUS;
{`OP_WRITE,`ABSTRACTCS} : State <= W_ABSTRACTCS;
{`OP_READ,`ABSTRACTCS} : State <= R_ABSTRACTCS;
{`OP_WRITE,`COMMAND} : State <= ABST_COMMAND;
{`OP_READ,`COMMAND} : State <= READ_ZERO;
{`OP_WRITE,`SBCS} : State <= READ_ZERO;
{`OP_READ,`SBCS} : State <= R_SYSBUSCS;
{2'bx,`HARTINFO},
{2'bx,`ABSTRACTAUTO},
{2'bx,`NEXTDM} : State <= READ_ZERO;
default : State <= INVALID;
endcase
end
R_DATA : begin
if (Busy)
CmdErr <= ~|CmdErr ? `CMDERR_BUSY : CmdErr;
case (ReqAddress)
`DATA0 : RspData <= Data0;
`DATA1 : RspData <= Data1;
`DATA2 : RspData <= Data2;
`DATA3 : RspData <= Data3;
endcase
RspOP <= `OP_SUCCESS;
State <= ACK;
end
W_DATA : begin
if (Busy)
CmdErr <= ~|CmdErr ? `CMDERR_BUSY : CmdErr;
RspOP <= `OP_SUCCESS;
State <= ACK;
end
W_DMCONTROL : begin
// While an abstract command is executing (busy in abstractcs is high), a debugger must not change
// hartsel, and must not write 1 to haltreq, resumereq, ackhavereset, setresethaltreq, or clrresethaltreq
if (Busy & (ReqData[`HALTREQ] | ReqData[`RESUMEREQ] | ReqData[`ACKHAVERESET] | ReqData[`SETRESETHALTREQ] | ReqData[`CLRRESETHALTREQ]))
CmdErr <= ~|CmdErr ? `CMDERR_BUSY : CmdErr;
else begin
HaltReq <= ReqData[`HALTREQ];
AckUnavail <= ReqData[`ACKUNAVAIL];
NdmReset <= ReqData[`NDMRESET];
DmActive <= ReqData[`DMACTIVE]; // Writing 0 here resets the DM
// On any given write, a debugger may only write 1 to at most one of the following bits: resumereq,
// hartreset, ackhavereset, setresethaltreq, and clrresethaltreq. The others must be written 0
case ({ReqData[`RESUMEREQ],ReqData[`ACKHAVERESET],ReqData[`SETRESETHALTREQ],ReqData[`CLRRESETHALTREQ]})
4'b0000 :; // None
4'b1000 : ResumeReq <= 1;
4'b0100 : AckHaveReset <= 1;
4'b0010 : HaltOnReset <= 1;
4'b0001 : HaltOnReset <= 0;
default : begin // Invalid (not onehot), dont write any changes
HaltReq <= HaltReq;
AckUnavail <= AckUnavail;
NdmReset <= NdmReset;
DmActive <= DmActive;
end
endcase
end
RspOP <= `OP_SUCCESS;
State <= ACK;
end
R_DMCONTROL : begin
RspData <= DMControl;
RspOP <= `OP_SUCCESS;
State <= ACK;
end
DMSTATUS : begin
RspData <= DMStatus;
RspOP <= `OP_SUCCESS;
State <= ACK;
end
W_ABSTRACTCS : begin
if (Busy)
CmdErr <= ~|CmdErr ? `CMDERR_BUSY : CmdErr;
else
CmdErr <= |ReqData[`CMDERR] ? `CMDERR_NONE : CmdErr; // clear CmdErr
RspOP <= `OP_SUCCESS;
State <= ACK;
end
R_ABSTRACTCS : begin
RspData <= AbstractCS;
RspOP <= `OP_SUCCESS;
State <= ACK;
end
ABST_COMMAND : begin
if (CmdErr != `CMDERR_NONE); // If CmdErr, do nothing
else if (Busy)
CmdErr <= `CMDERR_BUSY; // If Busy, set CmdErr, do nothing
else if (~Halted)
CmdErr <= `CMDERR_HALTRESUME; // If not halted, set CmdErr, do nothing
else begin
case (ReqData[`CMDTYPE])
`ACCESS_REGISTER : begin
if (ReqData[`AARSIZE] > $clog2(P.LLEN/8)) // if AARSIZE (encoded) is greater than P.LLEN, set CmdErr, do nothing
CmdErr <= `CMDERR_BUS;
else if (~ReqData[`TRANSFER]); // If not TRANSFER, do nothing
else if (InvalidRegNo)
CmdErr <= `CMDERR_EXCEPTION; // If InvalidRegNo, set CmdErr, do nothing
else if (ReqData[`AARWRITE] & RegReadOnly)
CmdErr <= `CMDERR_NOT_SUPPORTED; // If writing to a read only register, set CmdErr, do nothing
else begin
AcWrite <= ReqData[`AARWRITE];
NewAcState <= AC_SCAN;
end
end
//`QUICK_ACCESS : State <= QUICK_ACCESS;
//`ACCESS_MEMORY : State <= ACCESS_MEMORY;
default : CmdErr <= `CMDERR_NOT_SUPPORTED;
endcase
end
RspOP <= `OP_SUCCESS;
State <= ACK;
end
R_SYSBUSCS : begin
RspData <= SysBusCS;
RspOP <= `OP_SUCCESS;
State <= ACK;
end
READ_ZERO : begin // Writes ignored, Read Zero
RspData <= 0;
RspOP <= `OP_SUCCESS;
State <= ACK;
end
INVALID : begin
RspOP <= `OP_FAILED;
State <= ACK;
end
endcase
end
end
// Abstract command engine
// Due to length of the register scan chain,
// abstract commands execute independently of other DM operations
always_ff @(posedge clk) begin
if (rst)
AcState <= AC_IDLE;
else begin
case (AcState)
AC_IDLE : begin
Cycle <= 0;
case (NewAcState)
AC_SCAN : AcState <= ~AcWrite ? AC_CAPTURE : AC_SCAN;
endcase
end
AC_CAPTURE : begin
AcState <= AC_SCAN;
end
AC_SCAN : begin
if ((GPRegNo | FPRegNo) & AcWrite & (Cycle == ScanChainLen)) // Writes to GPR/FPR are shifted in len(GPR) or len(FPR) cycles
AcState <= AC_UPDATE;
else if ((GPRegNo | FPRegNo) & ~AcWrite & (Cycle == P.LLEN)) // Reads from GPR/FPR are shifted in len(ScanReg) cycles
AcState <= AC_IDLE;
else if (~(GPRegNo | FPRegNo) & (Cycle == ScanChainLen)) // Misc scanchain must be scanned completely
AcState <= AC_IDLE;
else
Cycle <= Cycle + 1;
end
AC_UPDATE : begin
AcState <= AC_IDLE;
end
endcase
end
end
assign Busy = ~(AcState == AC_IDLE);
// Scan Chain
assign DebugScanEn = (AcState == AC_SCAN);
assign DebugCapture = (AcState == AC_CAPTURE);
assign DebugRegUpdate = (AcState == AC_UPDATE);
assign MiscSel = ~(CSRegNo | GPRegNo | FPRegNo) & (AcState != AC_IDLE);
assign CSRSel = CSRegNo & (AcState != AC_IDLE);
assign GPRSel = GPRegNo & (AcState != AC_IDLE);
assign FPRSel = FPRegNo & (AcState != AC_IDLE);
assign DebugScanOut = ScanReg[0];
always_comb begin
case ({CSRSel, GPRSel, FPRSel})
3'b100 : ScanReg[P.LLEN] = CSRScanIn;
3'b010 : ScanReg[P.LLEN] = GPRScanIn;
3'b001 : ScanReg[P.LLEN] = FPRScanIn;
default : ScanReg[P.LLEN] = DebugScanIn;
endcase
end
if (P.LLEN == 32)
assign PackedDataReg = Data0;
else if (P.LLEN == 64)
assign PackedDataReg = {Data1,Data0};
else if (P.LLEN == 128)
assign PackedDataReg = {Data3,Data2,Data1,Data0};
// Load data from message registers into scan chain
assign WriteScanReg = AcWrite & (~(GPRegNo | FPRegNo) & (Cycle == ShiftCount) | (GPRegNo | FPRegNo) & (Cycle == 0));
genvar i;
for (i=0; i<P.LLEN; i=i+1) begin
// ARMask is used as write enable for subword overwrites (basic mask would overwrite neighbors in the chain)
assign ScanNext[i] = WriteScanReg & ARMask[i] ? PackedDataReg[i] : ScanReg[i+1];
flopenr #(1) scanreg (.clk, .reset(rst), .en(AcState == AC_SCAN), .d(ScanNext[i]), .q(ScanReg[i]));
end
// Message Registers
assign MaskedScanReg = ARMask & ScanReg[P.LLEN:1];
assign WriteMsgReg = (State == W_DATA) & ~Busy;
assign StoreScanChain = (AcState == AC_SCAN) & (Cycle == ShiftCount) & ~AcWrite;
assign Data0Wr = WriteMsgReg ? ReqData : MaskedScanReg[31:0];
flopenr #(32) data0reg (.clk, .reset(rst), .en(StoreScanChain | WriteMsgReg & (ReqAddress == `DATA0)), .d(Data0Wr), .q(Data0));
if (P.LLEN >= 64) begin
assign Data1Wr = WriteMsgReg ? ReqData : MaskedScanReg[63:32];
flopenr #(32) data1reg (.clk, .reset(rst), .en(StoreScanChain | WriteMsgReg & (ReqAddress == `DATA1)), .d(Data1Wr), .q(Data1));
end
if (P.LLEN == 128) begin
assign Data2Wr = WriteMsgReg ? ReqData : MaskedScanReg[95:64];
assign Data3Wr = WriteMsgReg ? ReqData : MaskedScanReg[127:96];
flopenr #(32) data2reg (.clk, .reset(rst), .en(StoreScanChain | WriteMsgReg & (ReqAddress == `DATA2)), .d(Data2Wr), .q(Data2));
flopenr #(32) data3reg (.clk, .reset(rst), .en(StoreScanChain | WriteMsgReg & (ReqAddress == `DATA3)), .d(Data3Wr), .q(Data3));
end
rad #(P) regnodecode(.AarSize(ReqData[`AARSIZE]),.Regno(ReqData[`REGNO]),.CSRegNo,.GPRegNo,.FPRegNo,.ScanChainLen,.ShiftCount,.InvalidRegNo,.RegReadOnly,.RegAddr,.ARMask);
endmodule