io_device.hh

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/*
 * Copyright (c) 2012 ARM Limited
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 * to a hardware implementation of the functionality of the software
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#ifndef __DEV_IO_DEVICE_HH__
#define __DEV_IO_DEVICE_HH__
 
#include "mem/tport.hh"
#include "params/BasicPioDevice.hh"
#include "params/PioDevice.hh"
#include "sim/clocked_object.hh"
 
namespace gem5
{
 
class PioDevice;
class System;
 
template <class Device>
class PioPort : public SimpleTimingPort
{
  protected:
    Device *device;
 
    Tick
    recvAtomic(PacketPtr pkt) override
    {
        // Technically the packet only reaches us after the header delay,
        // and typically we also need to deserialise any payload.
        Tick receive_delay = pkt->headerDelay + pkt->payloadDelay;
        pkt->headerDelay = pkt->payloadDelay = 0;
 
        const Tick delay =
            pkt->isRead() ? device->read(pkt) : device->write(pkt);
        assert(pkt->isResponse() || pkt->isError());
        return delay + receive_delay;
    }
 
    AddrRangeList
    getAddrRanges() const override
    {
        return device->getAddrRanges();
    }
 
  public:
    PioPort(Device *dev) :
        SimpleTimingPort(dev->name() + ".pio", dev), device(dev)
    {}
};
 
class PioDevice : public ClockedObject
{
  protected:
    System *sys;
 
    PioPort<PioDevice> pioPort;
 
    virtual AddrRangeList getAddrRanges() const = 0;
 
    virtual Tick read(PacketPtr pkt) = 0;
 
    virtual Tick write(PacketPtr pkt) = 0;
 
  public:
    using Params = PioDeviceParams;
    PioDevice(const Params &p);
    virtual ~PioDevice();
 
    void init() override;
 
    Port &getPort(const std::string &if_name,
            PortID idx=InvalidPortID) override;
 
    friend class PioPort<PioDevice>;
 
};
 
class BasicPioDevice : public PioDevice
{
  protected:
    Addr pioAddr;
 
    Addr pioSize;
 
    Tick pioDelay;
 
  public:
    PARAMS(BasicPioDevice);
    BasicPioDevice(const Params &p, Addr size);
 
    AddrRangeList getAddrRanges() const override;
};
 
} // namespace gem5
 
#endif // __DEV_IO_DEVICE_HH__