1/*
2 * Copyright (c) 2012 ARM Limited
3 * All rights reserved.
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2004-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Ali Saidi
41 *          Nathan Binkert
42 */
43
44#ifndef __DEV_IO_DEVICE_HH__
45#define __DEV_IO_DEVICE_HH__
46
47#include "mem/tport.hh"
48#include "params/BasicPioDevice.hh"
49#include "params/PioDevice.hh"
50#include "sim/clocked_object.hh"
51
52class PioDevice;
53class System;
54
55/**
56 * The PioPort class is a programmed i/o port that all devices that are
57 * sensitive to an address range use. The port takes all the memory
58 * access types and roles them into one read() and write() call that the device
59 * must respond to. The device must also provide getAddrRanges() function
60 * with which it returns the address ranges it is interested in.
61 */
62template <class Device>
63class PioPort : public SimpleTimingPort
64{
65  protected:
66    /** The device that this port serves. */
67    Device *device;
68
69    Tick
70    recvAtomic(PacketPtr pkt) override
71    {
72        // Technically the packet only reaches us after the header delay,
73        // and typically we also need to deserialise any payload.
74        Tick receive_delay = pkt->headerDelay + pkt->payloadDelay;
75        pkt->headerDelay = pkt->payloadDelay = 0;
76
77        const Tick delay =
78            pkt->isRead() ? device->read(pkt) : device->write(pkt);
79        assert(pkt->isResponse() || pkt->isError());
80        return delay + receive_delay;
81    }
82
83    AddrRangeList
84    getAddrRanges() const override
85    {
86        return device->getAddrRanges();
87    }
88
89  public:
90    PioPort(Device *dev) :
91        SimpleTimingPort(dev->name() + ".pio", dev), device(dev)
92    {}
93};
94
95/**
96 * This device is the base class which all devices senstive to an address range
97 * inherit from. There are three pure virtual functions which all devices must
98 * implement getAddrRanges(), read(), and write(). The magic do choose which
99 * mode we are in, etc is handled by the PioPort so the device doesn't have to
100 * bother.
101 */
102class PioDevice : public ClockedObject
103{
104  protected:
105    System *sys;
106
107    /** The pioPort that handles the requests for us and provides us requests
108     * that it sees. */
109    PioPort<PioDevice> pioPort;
110
111    /**
112     * Every PIO device is obliged to provide an implementation that
113     * returns the address ranges the device responds to.
114     *
115     * @return a list of non-overlapping address ranges
116     */
117    virtual AddrRangeList getAddrRanges() const = 0;
118
119    /** Pure virtual function that the device must implement. Called
120     * when a read command is recieved by the port.
121     * @param pkt Packet describing this request
122     * @return number of ticks it took to complete
123     */
124    virtual Tick read(PacketPtr pkt) = 0;
125
126    /** Pure virtual function that the device must implement. Called when a
127     * write command is recieved by the port.
128     * @param pkt Packet describing this request
129     * @return number of ticks it took to complete
130     */
131    virtual Tick write(PacketPtr pkt) = 0;
132
133  public:
134    typedef PioDeviceParams Params;
135    PioDevice(const Params *p);
136    virtual ~PioDevice();
137
138    const Params *
139    params() const
140    {
141        return dynamic_cast<const Params *>(_params);
142    }
143
144    void init() override;
145
146    Port &getPort(const std::string &if_name,
147            PortID idx=InvalidPortID) override;
148
149    friend class PioPort<PioDevice>;
150
151};
152
153class BasicPioDevice : public PioDevice
154{
155  protected:
156    /** Address that the device listens to. */
157    Addr pioAddr;
158
159    /** Size that the device's address range. */
160    Addr pioSize;
161
162    /** Delay that the device experinces on an access. */
163    Tick pioDelay;
164
165  public:
166    typedef BasicPioDeviceParams Params;
167    BasicPioDevice(const Params *p, Addr size);
168
169    const Params *
170    params() const
171    {
172        return dynamic_cast<const Params *>(_params);
173    }
174
175    /**
176     * Determine the address ranges that this device responds to.
177     *
178     * @return a list of non-overlapping address ranges
179     */
180    AddrRangeList getAddrRanges() const override;
181};
182
183#endif // __DEV_IO_DEVICE_HH__
184