AmdFlash.cc

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#include "AmdFlash.hh"
#include "Rom.hh"
#include "SRAM.hh"
#include "MSXMotherBoard.hh"
#include "MSXCPU.hh"
#include "MSXDevice.hh"
#include "CliComm.hh"
#include "HardwareConfig.hh"
#include "MSXException.hh"
#include "one_of.hh"
#include "ranges.hh"
#include "serialize.hh"
#include "xrange.hh"
#include <bit>
#include <cstring>
#include <cassert>
#include <iterator>
#include <memory>
 
namespace openmsx {
 
AmdFlash::AmdFlash(const Rom& rom, std::span<const SectorInfo> sectorInfo_,
                   word ID_, Addressing addressing_,
                   const DeviceConfig& config, Load load)
        : motherBoard(config.getMotherBoard())
        , sectorInfo(std::move(sectorInfo_))
        , size(sum(sectorInfo, &SectorInfo::size))
        , ID(ID_)
        , addressing(addressing_)
{
        init(rom.getName() + "_flash", config, load, &rom);
}
 
AmdFlash::AmdFlash(const std::string& name, std::span<const SectorInfo> sectorInfo_,
                   word ID_, Addressing addressing_,
                   const DeviceConfig& config)
        : motherBoard(config.getMotherBoard())
        , sectorInfo(std::move(sectorInfo_))
        , size(sum(sectorInfo, &SectorInfo::size))
        , ID(ID_)
        , addressing(addressing_)
{
        init(name, config, Load::NORMAL, nullptr);
}
 
[[nodiscard]] static bool sramEmpty(const SRAM& ram)
{
        return ranges::all_of(xrange(ram.getSize()),
                              [&](auto i) { return ram[i] == 0xFF; });
}
 
void AmdFlash::init(const std::string& name, const DeviceConfig& config, Load load, const Rom* rom)
{
        assert(std::has_single_bit(getSize()));
 
        auto numSectors = sectorInfo.size();
 
        unsigned writableSize = 0;
        unsigned readOnlySize = 0;
        writeAddress.resize(numSectors);
        for (auto i : xrange(numSectors)) {
                if (sectorInfo[i].writeProtected) {
                        writeAddress[i] = -1;
                        readOnlySize += sectorInfo[i].size;
                } else {
                        writeAddress[i] = writableSize;
                        writableSize += sectorInfo[i].size;
                }
        }
        assert((writableSize + readOnlySize) == getSize());
 
        bool loaded = false;
        if (writableSize) {
                if (load == Load::NORMAL) {
                        ram = std::make_unique<SRAM>(
                                name, "flash rom",
                                writableSize, config, nullptr, &loaded);
                } else {
                        // Hack for 'Matra INK', flash chip is wired-up so that
                        // writes are never visible to the MSX (but the flash
                        // is not made write-protected). In this case it doesn't
                        // make sense to load/save the SRAM file.
                        ram = std::make_unique<SRAM>(
                                name, "flash rom",
                                writableSize, config, SRAM::DontLoadTag{});
                }
        }
        if (readOnlySize) {
                // If some part of the flash is read-only we require a ROM
                // constructor parameter.
                assert(rom);
        }
 
        const auto* romTag = config.getXML()->findChild("rom");
        bool initialContentSpecified = romTag && romTag->findChild("sha1");
 
        // check whether the loaded SRAM is empty, whilst initial content was specified
        if (!rom && loaded && initialContentSpecified && sramEmpty(*ram)) {
                config.getCliComm().printInfo(
                        "This flash device (", config.getHardwareConfig().getName(),
                        ") has initial content specified, but this content "
                        "was not loaded, because there was already content found "
                        "and loaded from persistent storage. However, this "
                        "content is blank (it was probably created automatically "
                        "when the specified initial content could not be loaded "
                        "when this device was used for the first time). If you "
                        "still wish to load the specified initial content, "
                        "please remove the blank persistent storage file: ",
                        ram->getLoadedFilename());
        }
 
        std::unique_ptr<Rom> rom_;
        if (!rom && !loaded) {
                // If we don't have a ROM constructor parameter and there was
                // no sram content loaded (= previous persistent flash
                // content), then try to load some initial content. This
                // represents the original content of the flash when the device
                // ships. This ROM is optional, if it's not found, then the
                // initial flash content is all 0xFF.
                try {
                        rom_ = std::make_unique<Rom>(
                                "", "", // dummy name and description
                                config);
                        rom = rom_.get();
                        config.getCliComm().printInfo(
                                "Loaded initial content for flash ROM from ",
                                rom->getFilename());
                } catch (MSXException& e) {
                        // ignore error
                        assert(rom == nullptr); // 'rom' remains nullptr
                        // only if an actual sha1sum was given, tell the user we failed to use it
                        if (initialContentSpecified) {
                                config.getCliComm().printWarning(
                                        "Could not load specified initial content "
                                        "for flash ROM: ", e.getMessage());
                        }
                }
        }
 
        readAddress.resize(numSectors);
        unsigned romSize = rom ? rom->getSize() : 0;
        unsigned offset = 0;
        for (auto i : xrange(numSectors)) {
                unsigned sectorSize = sectorInfo[i].size;
                if (isSectorWritable(unsigned(i))) {
                        readAddress[i] = &(*ram)[writeAddress[i]];
                        if (!loaded) {
                                auto* ramPtr = const_cast<byte*>(
                                        &(*ram)[writeAddress[i]]);
                                if (offset >= romSize) {
                                        // completely past end of rom
                                        memset(ramPtr, 0xFF, sectorSize);
                                } else if (offset + sectorSize >= romSize) {
                                        // partial overlap
                                        unsigned last = romSize - offset;
                                        unsigned missing = sectorSize - last;
                                        const byte* romPtr = &(*rom)[offset];
                                        memcpy(ramPtr, romPtr, last);
                                        memset(ramPtr + last, 0xFF, missing);
                                } else {
                                        // completely before end of rom
                                        const byte* romPtr = &(*rom)[offset];
                                        memcpy(ramPtr, romPtr, sectorSize);
                                }
                        }
                } else {
                        assert(rom); // must have rom constructor parameter
                        if ((offset + sectorSize) <= romSize) {
                                readAddress[i] = &(*rom)[offset];
                        } else {
                                readAddress[i] = nullptr;
                        }
                }
                offset += sectorSize;
        }
        assert(offset == getSize());
 
        reset();
}
 
AmdFlash::~AmdFlash() = default;
 
AmdFlash::GetSectorInfoResult AmdFlash::getSectorInfo(unsigned address) const
{
        address &= getSize() - 1;
        auto it = sectorInfo.begin();
        unsigned sector = 0;
        while (address >= it->size) {
                address -= it->size;
                ++sector;
                ++it;
                assert(it != sectorInfo.end());
        }
        unsigned sectorSize = it->size;
        unsigned offset = address;
        return {sector, sectorSize, offset};
}
 
void AmdFlash::reset()
{
        cmdIdx = 0;
        setState(ST_IDLE);
}
 
void AmdFlash::setState(State newState)
{
        if (state == newState) return;
        state = newState;
        motherBoard.getCPU().invalidateAllSlotsRWCache(0x0000, 0x10000);
}
 
byte AmdFlash::peek(unsigned address) const
{
        auto [sector, sectorSize, offset] = getSectorInfo(address);
        if (state == ST_IDLE) {
                if (const byte* addr = readAddress[sector]) {
                        return addr[offset];
                } else {
                        return 0xFF;
                }
        } else {
                if (addressing == Addressing::BITS_12) {
                        // convert the address to the '11 bit case'
                        address >>= 1;
                }
                switch (address & 3) {
                case 0:
                        return ID >> 8;
                case 1:
                        return ID & 0xFF;
                case 2:
                        // 1 -> write protected
                        return isSectorWritable(sector) ? 0 : 1;
                case 3:
                default:
                        // TODO what is this? According to this it reads as '1'
                        //  http://www.msx.org/forumtopicl8329.html
                        return 1;
                }
        }
}
 
bool AmdFlash::isSectorWritable(unsigned sector) const
{
        return vppWpPinLow && (sector == one_of(0u, 1u)) ? false : (writeAddress[sector] != -1) ;
}
 
byte AmdFlash::read(unsigned address) const
{
        // note: after a read we stay in the same mode
        return peek(address);
}
 
const byte* AmdFlash::getReadCacheLine(unsigned address) const
{
        if (state == ST_IDLE) {
                auto [sector, sectorSize, offset] = getSectorInfo(address);
                const byte* addr = readAddress[sector];
                return addr ? &addr[offset] : MSXDevice::unmappedRead;
        } else {
                return nullptr;
        }
}
 
void AmdFlash::write(unsigned address, byte value)
{
        assert(cmdIdx < MAX_CMD_SIZE);
        cmd[cmdIdx].addr = address;
        cmd[cmdIdx].value = value;
        ++cmdIdx;
        if (checkCommandManufacturer() ||
            checkCommandEraseSector() ||
            checkCommandProgram() ||
            checkCommandDoubleByteProgram() ||
            checkCommandQuadrupleByteProgram() ||
            checkCommandEraseChip() ||
            checkCommandReset()) {
                // do nothing, we're still matching a command, but it is not complete yet
        } else {
                reset();
        }
}
 
// The checkCommandXXX() methods below return
//   true  -> if the command sequence still matches, but is not complete yet
//   false -> if the command was fully matched or does not match with
//            the current command sequence.
// If there was a full match, the command is also executed.
bool AmdFlash::checkCommandReset()
{
        if (cmd[0].value == 0xf0) {
                reset();
        }
        return false;
}
 
bool AmdFlash::checkCommandEraseSector()
{
        static constexpr byte cmdSeq[] = { 0xaa, 0x55, 0x80, 0xaa, 0x55 };
        if (partialMatch(5, cmdSeq)) {
                if (cmdIdx < 6) return true;
                if (cmd[5].value == 0x30) {
                        unsigned addr = cmd[5].addr;
                        auto [sector, sectorSize, offset] = getSectorInfo(addr);
                        if (isSectorWritable(sector)) {
                                ram->memset(writeAddress[sector],
                                            0xff, sectorSize);
                        }
                }
        }
        return false;
}
 
bool AmdFlash::checkCommandEraseChip()
{
        static constexpr byte cmdSeq[] = { 0xaa, 0x55, 0x80, 0xaa, 0x55 };
        if (partialMatch(5, cmdSeq)) {
                if (cmdIdx < 6) return true;
                if (cmd[5].value == 0x10) {
                        if (ram) ram->memset(0, 0xff, ram->getSize());
                }
        }
        return false;
}
 
bool AmdFlash::checkCommandProgramHelper(unsigned numBytes, const byte* cmdSeq, size_t cmdLen)
{
        if (partialMatch(cmdLen, cmdSeq)) {
                if (cmdIdx < (cmdLen + numBytes)) return true;
                for (auto i : xrange(cmdLen, cmdLen + numBytes)) {
                        unsigned addr = cmd[i].addr;
                        auto [sector, sectorSize, offset] = getSectorInfo(addr);
                        if (isSectorWritable(sector)) {
                                unsigned ramAddr = writeAddress[sector] + offset;
                                ram->write(ramAddr, (*ram)[ramAddr] & cmd[i].value);
                        }
                }
        }
        return false;
}
 
bool AmdFlash::checkCommandProgram()
{
        static constexpr byte cmdSeq[] = { 0xaa, 0x55, 0xa0 };
        return checkCommandProgramHelper(1, cmdSeq, std::size(cmdSeq));
}
 
bool AmdFlash::checkCommandDoubleByteProgram()
{
        static constexpr byte cmdSeq[] = { 0x50 };
        return checkCommandProgramHelper(2, cmdSeq, std::size(cmdSeq));
}
 
bool AmdFlash::checkCommandQuadrupleByteProgram()
{
        static constexpr byte cmdSeq[] = { 0x56 };
        return checkCommandProgramHelper(4, cmdSeq, std::size(cmdSeq));
}
 
bool AmdFlash::checkCommandManufacturer()
{
        static constexpr byte cmdSeq[] = { 0xaa, 0x55, 0x90 };
        if (partialMatch(3, cmdSeq)) {
                if (cmdIdx == 3) {
                        setState(ST_IDENT);
                }
                if (cmdIdx < 4) return true;
        }
        return false;
}
 
bool AmdFlash::partialMatch(size_t len, const byte* dataSeq) const
{
        static constexpr unsigned addrSeq[] = { 0, 1, 0, 0, 1 };
        unsigned cmdAddr[2] = { 0x555, 0x2aa };
 
        assert(len <= 5);
        for (auto i : xrange(std::min(unsigned(len), cmdIdx))) {
                // convert the address to the '11 bit case'
                unsigned addr = (addressing == Addressing::BITS_12) ? cmd[i].addr >> 1 : cmd[i].addr;
                if (((addr & 0x7FF) != cmdAddr[addrSeq[i]]) ||
                    (cmd[i].value != dataSeq[i])) {
                        return false;
                }
        }
        return true;
}
 
 
static constexpr std::initializer_list<enum_string<AmdFlash::State>> stateInfo = {
        { "IDLE",  AmdFlash::ST_IDLE  },
        { "IDENT", AmdFlash::ST_IDENT }
};
SERIALIZE_ENUM(AmdFlash::State, stateInfo);
 
template<typename Archive>
void AmdFlash::AmdCmd::serialize(Archive& ar, unsigned /*version*/)
{
        ar.serialize("address", addr,
                     "value",   value);
}
 
template<typename Archive>
void AmdFlash::serialize(Archive& ar, unsigned version)
{
        ar.serialize("ram",    *ram,
                     "cmd",    cmd,
                     "cmdIdx", cmdIdx,
                     "state",  state);
        if (ar.versionAtLeast(version, 2)) {
                ar.serialize("vppWpPinLow", vppWpPinLow);
        }
}
INSTANTIATE_SERIALIZE_METHODS(AmdFlash);
 
} // namespace openmsx