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// ----------------------------------------------------------------------------

// SystemC JTAG driver

// Copyright (C) 2008  Embecosm Limited <info@embecosm.com>

// Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

// This file is part of the cycle accurate model of the OpenRISC 1000 based

// system-on-chip, ORPSoC, built using Verilator.

// This program is free software: you can redistribute it and/or modify it

// under the terms of the GNU Lesser General Public License as published by

// the Free Software Foundation, either version 3 of the License, or (at your

// option) any later version.

// This program is distributed in the hope that it will be useful, but WITHOUT

// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public

// License for more details.

// You should have received a copy of the GNU Lesser General Public License

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

// ----------------------------------------------------------------------------

// $Id: JtagDriverSC.cpp 317 2009-02-22 19:52:12Z jeremy $

#include <iostream>

#include <iomanip>

#include "JtagDriverSC.h"

SC_HAS_PROCESS(JtagDriverSC);

//! Constructor for the JTAG driver.

//! We create a SC_THREAD in which we can spit out some actions. Must be a

//! thread, since we need to wait for the actions to complete.

//! @param[in] name             Name of this module, passed to the parent

//!                             constructor. 

//! @param[in] _tapActionQueue  Pointer to fifo of actions to perform

JtagDriverSC::JtagDriverSC(sc_core::sc_module_name name, sc_core::sc_fifo < TapAction * >*_tapActionQueue):

sc_module(name),

tapActionQueue(_tapActionQueue), currentScanChain(OR1K_SC_UNDEF)

{

        SC_THREAD(queueActions);

}                               // JtagDriverSC ()

//! SystemC thread to queue some actions

//! Have to use a thread, since we will end up waiting for actions to

//! complete.

void JtagDriverSC::queueActions()

{

        uint32_t res;           // General result variable

        // Reset the JTAG

        reset();

        // Select the register scan chain to stall the processor, stall the

        // processor and check it has stalled

        selectChain(OR1K_SC_REGISTER);

        writeReg(OR1K_RSC_RISCOP, RISCOP_STALL);

        do {

                res = readReg(OR1K_RSC_RISCOP);

                std::cout << sc_core::sc_time_stamp().to_seconds() * 1000000

                    << "us: RISCOP = " << std::hex << res << std::endl;

        }

        while ((res & RISCOP_STALL) != RISCOP_STALL);

        // Write the NPC SPR. Select the RISC_DEBUG scan chain, read the

        // register, write the register and read it back.

        selectChain(OR1K_SC_RISC_DEBUG);

        res = readReg(0x10);    // NPC

        std::cout << sc_core::sc_time_stamp().to_seconds() * 1000000

            << "us: Old NPC = " << std::hex << res << std::endl;

        writeReg(0x10, 0x4000100);

        res = readReg(0x10);    // NPC

        std::cout << sc_core::sc_time_stamp().to_seconds() * 1000000

            << "us: New NPC = " << std::hex << res << std::endl;

        // Unstall and check it has unstalled

        selectChain(OR1K_SC_REGISTER);

        writeReg(OR1K_RSC_RISCOP, 0);

        do {

                res = readReg(OR1K_RSC_RISCOP);

                std::cout << sc_core::sc_time_stamp().to_seconds() * 1000000

                    << "us: RISCOP = " << std::hex << res << std::endl;

        }

        while ((res & RISCOP_STALL) == RISCOP_STALL);

}                               // queueActions ()

//! Reset the JTAG

//! @note Must be called from a SystemC thread, because of the use of wait()

void JtagDriverSC::reset()

{

        sc_core::sc_event * actionDone = new sc_core::sc_event();

        TapActionReset *resetAction;

        // Create and queue the reset action and wait for it to complete

        resetAction = new TapActionReset(actionDone);

        tapActionQueue->write(resetAction);

        wait(*actionDone);

        delete resetAction;

        delete actionDone;

}                               // reset ()

//! Select an OpenRISC 1000 scan chain

//! Built on top of the JTAG commands to shift registers

//! We only do something if the scan chain needs to be changed.

//! - Shift-IR the CHAIN_SELECT instruction

//! - Shift-DR the specified chain

//! - Shift-IR the DEBUG instruction

//! @note Must be called from a SystemC thread, because of the use of wait()

//! @param[in] chain  The desired scan chain

void JtagDriverSC::selectChain(int chain)

{

        if (chain == currentScanChain) {

                return;

        } else {

                currentScanChain = chain;

        }

        sc_core::sc_event * actionDone = new sc_core::sc_event();

        TapActionIRScan *iRScan;

        TapActionDRScan *dRScan;

        // Create and queue the IR-Scan action for CHAIN_SELECT (no CRC)

        iRScan = new TapActionIRScan(actionDone, CHAIN_SELECT_IR, JTAG_IR_LEN);

        tapActionQueue->write(iRScan);

        wait(*actionDone);

        delete iRScan;

        // Create and queue the DR-Scan action for the specified chain (which we

        // know will fit into 64 bits)

        uint64_t chainReg = crc8(chain, CHAIN_DR_LEN) << (CHAIN_DR_LEN) | chain;

        dRScan =

            new TapActionDRScan(actionDone, chainReg, CHAIN_DR_LEN + CRC_LEN);

        tapActionQueue->write(dRScan);

        wait(*actionDone);

        delete dRScan;

        // Create and queue the IR-Scan action for DEBUG (no CRC)

        iRScan = new TapActionIRScan(actionDone, DEBUG_IR, JTAG_IR_LEN);

        tapActionQueue->write(iRScan);

        wait(*actionDone);

        delete iRScan;

        delete actionDone;

}                               // selectChain()

//! Read an OpenRISC 1000 JTAG register

//! Built on top of the JTAG commands to shift registers

//! - Shift-DR the specified address with R/W field unset

//! - read out the data shifted out.

//! DR register fields depend on the scan chain in use. For SC_REGISTER:

//! -   [4:0] Address to read from

//! -     [5] 0 indicating read

//! -  [37:6] Unused

//! - [45:38] CRC (CRC-8-ATM)

//! For SC_RISC_DEBUG (i.e. SPRs) and SC_WISHBONE:

//! -  [31:0] Address to read from

//! -    [32] 0 indicating read

//! - [64:33] unused

//! - [72:65] CRC (CRC-8-ATM)

//! In general two Scan-DR loops are needed. The first will cause the value

//! associated with the address to be loaded into the shift register, the

//! second will actually shift that value out. So we use a subsidiary call to

//! do the read (::readReg1()). This allows a future extension, where a block

//! of registers are read efficiently by overlapping ScanDR actions.

//! We can also provide a variant of ::readReg1 () that is optimized for

//! "small" value.

//! @note Must be called from a SystemC thread, because of the use of wait()

//! @param[in] addr  The address of the register

//! @return  The register value read

uint32_t JtagDriverSC::readReg(uint32_t addr)

{

        bool firstTime = true;

        int bitSizeNoCrc;       // Size of reg w/o its CRC field

        // Determine the size of register to read.

        switch (currentScanChain) {

        case OR1K_SC_RISC_DEBUG:

                bitSizeNoCrc = RISC_DEBUG_DR_LEN;

                break;

        case OR1K_SC_REGISTER:

                bitSizeNoCrc = REGISTER_DR_LEN;

                break;

        case OR1K_SC_WISHBONE:

                bitSizeNoCrc = WISHBONE_DR_LEN;

                break;

        }

        // Read the register twice. Use an optimized version if the register is

        // "small".

        if ((bitSizeNoCrc + CRC_LEN) < 64) {

                (void)readReg1(addr, bitSizeNoCrc);

                return readReg1(addr, bitSizeNoCrc);

        } else {

                uint64_t *dReg =

                    new uint64_t[(bitSizeNoCrc + CRC_LEN + 63) / 64];

                (void)readReg1(dReg, addr, bitSizeNoCrc);

                uint32_t res = readReg1(dReg, addr, bitSizeNoCrc);

                delete[]dReg;

                return res;

        }

}                               // readReg ()

//! Single read of an OpenRISC 1000 JTAG register

//! Built on top of the JTAG commands to shift registers

//! - Shift-DR the specified address with R/W field unset

//! - read out the data shifted out.

//! This version is for "small" values represented as a uint64_t.

//! @note Must be called from a SystemC thread, because of the use of wait()

//! @param[in]     addr          The address to read

//! @param[in]     bitSizeNoCrc  Size of the register excluding its CRC field

//! @return  The register value read

uint32_t JtagDriverSC::readReg1(uint32_t addr, int bitSizeNoCrc)

{

        // Useful fields and sizes and the register itself

        int fullBitSize = bitSizeNoCrc + CRC_LEN;

        int dataOffset = bitSizeNoCrc - DR_DATA_LEN;

        uint64_t dReg;

        // Allocate space for the shifted reg and a SystemC completion event

        sc_core::sc_event * actionDone = new sc_core::sc_event();

        // Loop until CRCs match

        while (true) {

                // Create the data to shift in

                dReg = 0ULL;

                dReg |= addr;

                uint8_t crc_in = crc8(dReg, bitSizeNoCrc);

                dReg |= (uint64_t) crc_in << bitSizeNoCrc;

                // Prepare the action, queue it and wait for it to complete

                TapActionDRScan *dRScan = new TapActionDRScan(actionDone, dReg,

                                                              fullBitSize);

                tapActionQueue->write(dRScan);

                wait(*actionDone);

                dReg = dRScan->getDRegOut();

                delete dRScan;

                // Check CRCs

                uint8_t crc_out = dReg >> bitSizeNoCrc;

                uint8_t crc_calc = crc8(dReg, bitSizeNoCrc);

                // All done if CRC matches

                if (crc_out == crc_calc) {

                        delete actionDone;

                        return (dReg >> dataOffset) & ((1ULL << DR_DATA_LEN) -

                                                       1);

                }

        }

}                               // readReg1 ()

//! Single read of an OpenRISC 1000 JTAG register

//! Built on top of the JTAG commands to shift registers

//! - Shift-DR the specified address with R/W field unset

//! - read out the data shifted out.

//! This version is for "large" values represented as an array of uint64_t.

//! @note Must be called from a SystemC thread, because of the use of wait()

//! @param[in,out] dRegArray     The shift register to use

//! @param[in]     addr          The address to read

//! @param[in]     bitSizeNoCrc  Size of the register excluding its CRC field

//! @return  The register value read

uint32_t

    JtagDriverSC::readReg1(uint64_t * dRegArray,

                           uint32_t addr, int bitSizeNoCrc)

{

        // Useful fields and sizes

        int fullBitSize = bitSizeNoCrc + CRC_LEN;

        int dataOffset = bitSizeNoCrc - DR_DATA_LEN;

        // Allocate a SystemC completion event

        sc_core::sc_event * actionDone = new sc_core::sc_event();

        // Loop until CRCs match

        while (true) {

                // Create the data to shift in

                memset(dRegArray, 0, fullBitSize / 8);

                dRegArray[0] |= addr;

                uint8_t crc_in = crc8(dRegArray, bitSizeNoCrc);

                insertBits(crc_in, CRC_LEN, dRegArray, bitSizeNoCrc);

                // Prepare the action, queue it and wait for it to complete

                TapActionDRScan *dRScan =

                    new TapActionDRScan(actionDone, dRegArray,

                                        fullBitSize);

                tapActionQueue->write(dRScan);

                wait(*actionDone);

                dRScan->getDRegOut(dRegArray);

                delete dRScan;

                // Check CRCs

                uint8_t crc_out = extractBits(dRegArray, bitSizeNoCrc, CRC_LEN);

                uint8_t crc_calc = crc8(dRegArray, bitSizeNoCrc);

                // All done if CRC matches

                if (crc_out == crc_calc) {

                        delete actionDone;

                        return extractBits(dRegArray, dataOffset, DR_DATA_LEN);

                }

        }

}                               // readReg1 ()

//! Write an OpenRISC 1000 JTAG register

//! Built on top of the JTAG commands to shift registers

//! - Shift-DR the specified address with R/W field set and data to write

//! DR register fields depend on the scan chain in use. For SC_REGISTER:

//! -   [4:0] Address to write to

//! -     [5] 1 indicating write

//! -  [37:6] Value to write

//! - [45:38] CRC (CRC-8-ATM)

//! For SC_RISC_DEBUG (i.e. SPRs) and SC_WISHBONE:

//! -  [31:0] Address to write to

//! -    [32] 1 indicating write

//! - [64:33] Value to write

//! - [72:65] CRC (CRC-8-ATM)

//! @note Must be called from a SystemC thread, because of the use of wait()

//! @param[in] addr  The address of the register

//! @param[in] data  The register data to write

void

 JtagDriverSC::writeReg(uint32_t addr, uint32_t data)

{

        int bitSizeNoCrc;       // Size of reg w/o its CRC field

        uint64_t writeBit;      // Mask for the write enable bit

        // Determine the size of register to write.

        switch (currentScanChain) {

        case OR1K_SC_RISC_DEBUG:

                bitSizeNoCrc = RISC_DEBUG_DR_LEN;

                writeBit = RISC_DEBUG_RW;

                break;

        case OR1K_SC_REGISTER:

                bitSizeNoCrc = REGISTER_DR_LEN;

                writeBit = REGISTER_RW;

                break;

        case OR1K_SC_WISHBONE:

                bitSizeNoCrc = WISHBONE_DR_LEN;

                writeBit = WISHBONE_RW;

                break;

        }

        // Create the register in an array

        int wordSize = (bitSizeNoCrc + CRC_LEN + 63) / 64;

        uint64_t *dReg = new uint64_t[wordSize];

        // Create the data to shift in

        memset(dReg, 0, wordSize * 8);

        dReg[0] |= writeBit | addr;

        insertBits(data, DR_DATA_LEN, dReg, bitSizeNoCrc - DR_DATA_LEN);

        insertBits(crc8(dReg, bitSizeNoCrc), CRC_LEN, dReg, bitSizeNoCrc);

        // Prepare the action, queue it and wait for it to complete

        sc_core::sc_event * actionDone = new sc_core::sc_event();

        TapActionDRScan *dRScan = new TapActionDRScan(actionDone, dReg,

                                                      bitSizeNoCrc + CRC_LEN);

        tapActionQueue->write(dRScan);

        wait(*actionDone);

        delete[]dReg;

        delete dRScan;

        delete actionDone;

}                               // writeReg ()

//! Compute CRC-8-ATM

//! The data is in a uint64_t, for which we use the first size bits to compute

//! the CRC.

//! @Note I am using the same algorithm as the ORPSoC debug unit, but I

//!       believe its function is broken! I don't believe the data bit should

//!       feature in the computation of bits 2 & 1 of the new CRC.

//! @Note I've realized that this is an algorithm for LSB first, so maybe it

//!       is correct!

//! @param data  The data whose CRC is desired

//! @param size  The number of bits in the data

uint8_t JtagDriverSC::crc8(uint64_t data, int size)

{

        uint8_t crc = 0;

        for (int i = 0; i < size; i++) {

                uint8_t d = data & 1;   // Latest data bit

                data >>= 1;

                uint8_t oldCrc7 = (crc >> 7) & 1;

                uint8_t oldCrc1 = (crc >> 1) & 1;

                uint8_t oldCrc0 = (crc >> 0) & 1;

                uint8_t newCrc2 = d ^ oldCrc1 ^ oldCrc7;        // Why d?

                uint8_t newCrc1 = d ^ oldCrc0 ^ oldCrc7;        // Why d?

                uint8_t newCrc0 = d ^ oldCrc7;

                crc =

                    ((crc << 1) & 0xf8) | (newCrc2 << 2) | (newCrc1 << 1) |

                    newCrc0;

        }

        return crc;

}                               // crc8 ()

//! Compute CRC-8-ATM

//! The data is in an array of uint64_t, for which we use the first size bits

//! to compute the CRC.

//! @Note I am using the same algorithm as the ORPSoC debug unit, but I

//!       believe its function is broken! I don't believe the data bit should

//!       feature in the computation of bits 2 & 1 of the new CRC.

//! @Note I've realized that this is an algorithm for LSB first, so maybe it

//!       is correct!

//! @param dataArray  The array of data whose CRC is desired

//! @param size       The number of bits in the data

uint8_t JtagDriverSC::crc8(uint64_t dataArray[], int size)

{

        uint8_t crc = 0;

        for (int i = 0; i < size; i++) {

                uint8_t d = (dataArray[i / 64] >> (i % 64)) & 1;

                uint8_t oldCrc7 = (crc >> 7) & 1;

                uint8_t oldCrc1 = (crc >> 1) & 1;

                uint8_t oldCrc0 = (crc >> 0) & 1;

                uint8_t newCrc2 = d ^ oldCrc1 ^ oldCrc7;        // Why d?

                uint8_t newCrc1 = d ^ oldCrc0 ^ oldCrc7;        // Why d?

                uint8_t newCrc0 = d ^ oldCrc7;

                crc =

                    ((crc << 1) & 0xf8) | (newCrc2 << 2) | (newCrc1 << 1) |

                    newCrc0;

        }

        return crc;

}                               // crc8 ()

//! Utility to insert a string of bits into array

//! This is a simple overwriting

//! @param  str       Bits to insert

//! @param  strLen    Number of bits to insert

//! @param  array     Array into which to insert

//! @param  startBit  Offset at which to insert bits

void JtagDriverSC::insertBits(uint64_t str,

                              int strLen, uint64_t * array, int startBit)

{

        int startWord = startBit / 64;

        int endWord = (startBit + strLen - 1) / 64;

        startBit = startBit % 64;

        // Deal with the startWord. Get enough bits for the mask and put them in the

        // right place

        uint64_t startMask = ((1ULL << strLen) - 1ULL) << startBit;

        array[startWord] &= ~startMask;

        array[startWord] |= str << startBit;

        // If we were all in one word, we can give up now.

        if (startWord == endWord) {

                return;

        }

        // Deal with the endWord. Get enough bits for the mask. No need to shift

        // these up - they're always at the bottom of the word

        int bitsToDo = (startBit + strLen) % 64;

        uint64_t endMask = (1ULL << bitsToDo) - 1ULL;

        array[endWord] &= ~endMask;

        array[endWord] |= str >> (strLen - bitsToDo);

}                               // insertBits()

//! Utility to extract a string of bits from an array

//! @param  array     Array from which to extract

//! @param  startBit  Offset at which to extract bits

//! @param  strLen    Number of bits to extract

//! @return  Extracted bits

uint64_t JtagDriverSC::extractBits(uint64_t * array, int startBit, int strLen)

{

        int startWord = startBit / 64;

        int endWord = (startBit + strLen - 1) / 64;

        startBit = startBit % 64;

        // Deal with the startWord. Get enough bits for the mask and put them in the

        // right place

        uint64_t startMask = ((1ULL << strLen) - 1ULL) << startBit;

        uint64_t res = (array[startWord] & startMask) >> startBit;

        // If we were all in one word, we can give up now.

        if (startWord == endWord) {

                return res;

        }

        // Deal with the endWord. Get enough bits for the mask. No need to shift

        // these up - they're always at the bottom of the word

        int bitsToDo = (startBit + strLen) % 64;

        uint64_t endMask = (1ULL << bitsToDo) - 1ULL;

        return res | ((array[endWord] & endMask) << (strLen - bitsToDo));

}                               // extractBits ()