io_device.hh

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· HH 代码 · 共 304 行

/*
 * Copyright (c) 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 *
 * Authors: Ali G. Saidi
 *          Nathan L. Binkert
 */

#ifndef __DEV_IO_DEVICE_HH__
#define __DEV_IO_DEVICE_HH__

#include "mem/mem_object.hh"
#include "mem/packet.hh"
#include "mem/tport.hh"
#include "params/BasicPioDevice.hh"
#include "params/DmaDevice.hh"
#include "params/PioDevice.hh"
#include "sim/sim_object.hh"

class Event;
class Platform;
class PioDevice;
class DmaDevice;
class System;

/**
 * The PioPort class is a programmed i/o port that all devices that are
 * sensitive to an address range use. The port takes all the memory
 * access types and roles them into one read() and write() call that the device
 * must respond to. The device must also provide the addressRanges() function
 * with which it returns the address ranges it is interested in.
 */
class PioPort : public SimpleTimingPort
{
  protected:
    /** The device that this port serves. */
    PioDevice *device;

    virtual Tick recvAtomic(PacketPtr pkt);

    virtual void getDeviceAddressRanges(AddrRangeList &resp,
                                        bool &snoop);

  public:

    PioPort(PioDevice *dev, System *s, std::string pname = "-pioport");
};


class DmaPort : public Port
{
  protected:
    struct DmaReqState : public Packet::SenderState
    {
        /** Event to call on the device when this transaction (all packets)
         * complete. */
        Event *completionEvent;

        /** Where we came from for some sanity checking. */
        Port *outPort;

        /** Total number of bytes that this transaction involves. */
        Addr totBytes;

        /** Number of bytes that have been acked for this transaction. */
        Addr numBytes;

        DmaReqState(Event *ce, Port *p, Addr tb)
            : completionEvent(ce), outPort(p), totBytes(tb), numBytes(0)
        {}
    };

    DmaDevice *device;
    std::list<PacketPtr> transmitList;

    /** The system that device/port are in. This is used to select which mode
     * we are currently operating in. */
    System *sys;

    /** Number of outstanding packets the dma port has. */
    int pendingCount;

    /** If a dmaAction is in progress. */
    int actionInProgress;

    /** If we need to drain, keep the drain event around until we're done
     * here.*/
    Event *drainEvent;

    /** time to wait between sending another packet, increases as NACKs are
     * recived, decreases as responses are recived. */
    Tick backoffTime;

    /** If the port is currently waiting for a retry before it can send whatever
     * it is that it's sending. */
    bool inRetry;

    virtual bool recvTiming(PacketPtr pkt);
    virtual Tick recvAtomic(PacketPtr pkt)
    { panic("dma port shouldn't be used for pio access."); M5_DUMMY_RETURN }
    virtual void recvFunctional(PacketPtr pkt)
    { panic("dma port shouldn't be used for pio access."); }

    virtual void recvStatusChange(Status status)
    { ; }

    virtual void recvRetry() ;

    virtual void getDeviceAddressRanges(AddrRangeList &resp,
                                        bool &snoop)
    { resp.clear(); snoop = false; }

    void queueDma(PacketPtr pkt, bool front = false);
    void sendDma();

    /** event to give us a kick every time we backoff time is reached. */
    EventWrapper<DmaPort, &DmaPort::sendDma> backoffEvent;

  public:
    DmaPort(DmaDevice *dev, System *s);

    void dmaAction(Packet::Command cmd, Addr addr, int size, Event *event,
                   uint8_t *data = NULL);

    bool dmaPending() { return pendingCount > 0; }

    int cacheBlockSize() { return peerBlockSize(); }
    unsigned int drain(Event *de);
};

/**
 * This device is the base class which all devices senstive to an address range
 * inherit from. There are three pure virtual functions which all devices must
 * implement addressRanges(), read(), and write(). The magic do choose which
 * mode we are in, etc is handled by the PioPort so the device doesn't have to
 * bother.
 */
class PioDevice : public MemObject
{
  protected:

    /** The platform we are in. This is used to decide what type of memory
     * transaction we should perform. */
    Platform *platform;

    System *sys;

    /** The pioPort that handles the requests for us and provides us requests
     * that it sees. */
    PioPort *pioPort;

    virtual void addressRanges(AddrRangeList &range_list) = 0;

    /** Pure virtual function that the device must implement. Called
     * when a read command is recieved by the port.
     * @param pkt Packet describing this request
     * @return number of ticks it took to complete
     */
    virtual Tick read(PacketPtr pkt) = 0;

    /** Pure virtual function that the device must implement. Called when a
     * write command is recieved by the port.
     * @param pkt Packet describing this request
     * @return number of ticks it took to complete
     */
    virtual Tick write(PacketPtr pkt) = 0;

  public:
    typedef PioDeviceParams Params;
    PioDevice(const Params *p);
    virtual ~PioDevice();

    const Params *
    params() const
    {
        return dynamic_cast<const Params *>(_params);
    }

    virtual void init();

    virtual unsigned int drain(Event *de);

    virtual Port *getPort(const std::string &if_name, int idx = -1)
    {
        if (if_name == "pio") {
            if (pioPort != NULL)
                panic("pio port already connected to.");
            pioPort = new PioPort(this, sys);
            return pioPort;
        } else
            return NULL;
    }
    friend class PioPort;

};

class BasicPioDevice : public PioDevice
{
  protected:
    /** Address that the device listens to. */
    Addr pioAddr;

    /** Size that the device's address range. */
    Addr pioSize;

    /** Delay that the device experinces on an access. */
    Tick pioDelay;

  public:
    typedef BasicPioDeviceParams Params;
    BasicPioDevice(const Params *p);

    const Params *
    params() const
    {
        return dynamic_cast<const Params *>(_params);
    }

    /** return the address ranges that this device responds to.
     * @param range_list range list to populate with ranges
     */
    void addressRanges(AddrRangeList &range_list);

};

class DmaDevice : public PioDevice
{
   protected:
    DmaPort *dmaPort;
    Tick minBackoffDelay;
    Tick maxBackoffDelay;

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

    const Params *
    params() const
    {
        return dynamic_cast<const Params *>(_params);
    }

    void dmaWrite(Addr addr, int size, Event *event, uint8_t *data)
    {
        dmaPort->dmaAction(MemCmd::WriteReq, addr, size, event, data);
    }

    void dmaRead(Addr addr, int size, Event *event, uint8_t *data)
    {
        dmaPort->dmaAction(MemCmd::ReadReq, addr, size, event, data);
    }

    bool dmaPending() { return dmaPort->dmaPending(); }

    virtual unsigned int drain(Event *de);

    int cacheBlockSize() { return dmaPort->cacheBlockSize(); }

    virtual Port *getPort(const std::string &if_name, int idx = -1)
    {
        if (if_name == "pio") {
            if (pioPort != NULL)
                panic("pio port already connected to.");
            pioPort = new PioPort(this, sys);
            return pioPort;
        } else if (if_name == "dma") {
            if (dmaPort != NULL)
                panic("dma port already connected to.");
            dmaPort = new DmaPort(this, sys);
            return dmaPort;
        } else
            return NULL;
    }

    friend class DmaPort;
};


#endif // __DEV_IO_DEVICE_HH__