dma_device.hh

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 * property including but not limited to intellectual property relating
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 * licensed hereunder.  You may use the software subject to the license
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 *
 * Authors: Ali Saidi
 *          Nathan Binkert
 *          Andreas Sandberg
 */

#ifndef __DEV_DMA_DEVICE_HH__
#define __DEV_DMA_DEVICE_HH__

#include <deque>
#include <memory>

#include "base/circlebuf.hh"
#include "dev/io_device.hh"
#include "params/DmaDevice.hh"
#include "sim/drain.hh"
#include "sim/system.hh"

class DmaPort : public MasterPort, public Drainable
{
  private:

    void trySendTimingReq();

    void sendDma();

    void handleResp(PacketPtr pkt, Tick delay = 0);

    struct DmaReqState : public Packet::SenderState
    {
        Event *completionEvent;

        const Addr totBytes;

        Addr numBytes;

        const Tick delay;

        DmaReqState(Event *ce, Addr tb, Tick _delay)
            : completionEvent(ce), totBytes(tb), numBytes(0), delay(_delay)
        {}
    };

  public:
    MemObject *const device;

    System *const sys;

    const MasterID masterId;

  protected:
    std::deque<PacketPtr> transmitList;

    EventWrapper<DmaPort, &DmaPort::sendDma> sendEvent;

    uint32_t pendingCount;

    bool inRetry;

  protected:

    bool recvTimingResp(PacketPtr pkt) override;
    void recvReqRetry() override;

    void queueDma(PacketPtr pkt);

  public:

    DmaPort(MemObject *dev, System *s);

    RequestPtr dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
                         uint8_t *data, Tick delay, Request::Flags flag = 0);

    bool dmaPending() const { return pendingCount > 0; }

    DrainState drain() override;
};

class DmaDevice : public PioDevice
{
   protected:
    DmaPort dmaPort;

  public:
    typedef DmaDeviceParams Params;
    DmaDevice(const Params *p);
    virtual ~DmaDevice() { }

    void dmaWrite(Addr addr, int size, Event *event, uint8_t *data,
                  Tick delay = 0)
    {
        dmaPort.dmaAction(MemCmd::WriteReq, addr, size, event, data, delay);
    }

    void dmaRead(Addr addr, int size, Event *event, uint8_t *data,
                 Tick delay = 0)
    {
        dmaPort.dmaAction(MemCmd::ReadReq, addr, size, event, data, delay);
    }

    bool dmaPending() const { return dmaPort.dmaPending(); }

    void init() override;

    unsigned int cacheBlockSize() const { return sys->cacheLineSize(); }

    BaseMasterPort &getMasterPort(const std::string &if_name,
                                  PortID idx = InvalidPortID) override;

};

class DmaCallback : public Drainable
{
  public:
    virtual const std::string name() const { return "DmaCallback"; }

    DrainState drain() override
    {
        return count ? DrainState::Draining : DrainState::Drained;
    }

  protected:
    int count;

    DmaCallback()
        : count(0)
    { }

    virtual ~DmaCallback() { }

    virtual void process() = 0;

  private:
    void chunkComplete()
    {
        if (--count == 0) {
            process();
            // Need to notify DrainManager that this object is finished
            // draining, even though it is immediately deleted.
            signalDrainDone();
            delete this;
        }
    }

    class DmaChunkEvent : public Event
    {
      private:
        DmaCallback *callback;

      public:
        DmaChunkEvent(DmaCallback *cb)
          : Event(Default_Pri, AutoDelete), callback(cb)
        { }

        void process() { callback->chunkComplete(); }
    };

  public:

    Event *getChunkEvent()
    {
        ++count;
        return new DmaChunkEvent(this);
    }
};

class DmaReadFifo : public Drainable, public Serializable
{
  public:
    DmaReadFifo(DmaPort &port, size_t size,
                unsigned max_req_size,
                unsigned max_pending,
                Request::Flags flags = 0);

    ~DmaReadFifo();

  public: // Serializable
    void serialize(CheckpointOut &cp) const override;
    void unserialize(CheckpointIn &cp) override;

  public: // Drainable
    DrainState drain() override;

  public: // FIFO access
    bool tryGet(uint8_t *dst, size_t len);

    template<typename T>
    bool tryGet(T &value) {
        return tryGet(static_cast<T *>(&value), sizeof(T));
    };

    void get(uint8_t *dst, size_t len);

    template<typename T>
    T get() {
        T value;
        get(static_cast<uint8_t *>(&value), sizeof(T));
        return value;
    };

    size_t size() const { return buffer.size(); }
    void flush() { buffer.flush(); }

  public: // FIFO fill control
    void startFill(Addr start, size_t size);

    void stopFill();

    bool atEndOfBlock() const {
        return nextAddr == endAddr;
    }

    bool isActive() const {
        return !(pendingRequests.empty() && atEndOfBlock());
    }

  protected: // Callbacks
    virtual void onEndOfBlock() {};

    virtual void onIdle() {};

  private: // Configuration
    const Addr maxReqSize;
    const size_t fifoSize;
    const Request::Flags reqFlags;

    DmaPort &port;

  private:
    class DmaDoneEvent : public Event
    {
      public:
        DmaDoneEvent(DmaReadFifo *_parent, size_t max_size);

        void kill();
        void cancel();
        bool canceled() const { return _canceled; }
        void reset(size_t size);
        void process();

        bool done() const { return _done; }
        size_t requestSize() const { return _requestSize; }
        const uint8_t *data() const { return _data.data(); }
        uint8_t *data() { return _data.data(); }

      private:
        DmaReadFifo *parent;
        bool _done;
        bool _canceled;
        size_t _requestSize;
        std::vector<uint8_t> _data;
    };

    typedef std::unique_ptr<DmaDoneEvent> DmaDoneEventUPtr;

    void dmaDone();

    void handlePending();

    void resumeFill();

    void resumeFillTiming();

    void resumeFillFunctional();

  private: // Internal state
    Fifo<uint8_t> buffer;

    Addr nextAddr;
    Addr endAddr;

    std::deque<DmaDoneEventUPtr> pendingRequests;
    std::deque<DmaDoneEventUPtr> freeRequests;
};

#endif // __DEV_DMA_DEVICE_HH__