packet.hh revision 2632:1bb2f91485ea 
1/*
2 * Copyright (c) 2006 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/**
30 * @file
31 * Declaration of the Packet Class, a packet is a transaction occuring
32 * between a single level of the memory heirarchy (ie L1->L2).
33 */
34
35#ifndef __MEM_PACKET_HH__
36#define __MEM_PACKET_HH__
37
38#include "mem/request.hh"
39#include "arch/isa_traits.hh"
40#include "sim/root.hh"
41
42struct Packet;
43typedef Packet* PacketPtr;
44typedef uint8_t* PacketDataPtr;
45
46/** List of all commands associated with a packet. */
47enum Command
48{
49    Read,
50    Write
51};
52
53/** The result of a particular pakets request. */
54enum PacketResult
55{
56    Success,
57    BadAddress,
58    Unknown
59};
60
61class SenderState{};
62class Coherence{};
63
64/**
65 * A Packet is the structure to handle requests between two levels
66 * of the memory system.  The Request is a global object that trancends
67 * all of the memory heirarchy, but at each levels interface a packet
68 * is created to transfer data/requests.  For example, a request would
69 * be used to initiate a request to go to memory/IOdevices, as the request
70 * passes through the memory system several packets will be created.  One
71 * will be created to go between the L1 and L2 caches and another to go to
72 * the next level and so forth.
73 *
74 * Packets are assumed to be returned in the case of a single response.  If
75 * the transaction has no response, then the consumer will delete the packet.
76 */
77struct Packet
78{
79  private:
80   /** A pointer to the data being transfered.  It can be differnt sizes
81        at each level of the heirarchy so it belongs in the packet,
82        not request. This may or may not be populated when a responder recieves
83        the packet. If not populated it memory should be allocated.
84    */
85    PacketDataPtr data;
86
87    /** Is the data pointer set to a value that shouldn't be freed when the
88     * packet is destroyed? */
89    bool staticData;
90    /** The data pointer points to a value that should be freed when the packet
91     * is destroyed. */
92    bool dynamicData;
93    /** the data pointer points to an array (thus delete [] ) needs to be called
94     * on it rather than simply delete.*/
95    bool arrayData;
96
97
98  public:
99    /** The address of the request, could be virtual or physical (depending on
100        cache configurations). */
101    Addr addr;
102
103    /** Flag structure to hold flags for this particular packet */
104    uint64_t flags;
105
106    /** A pointer to the overall request. */
107    RequestPtr req;
108
109    /** A virtual base opaque structure used to hold
110        coherence status messages. */
111    Coherence *coherence;  // virtual base opaque,
112                           // assert(dynamic_cast<Foo>) etc.
113
114    /** A virtual base opaque structure used to hold the senders state. */
115    void *senderState; // virtual base opaque,
116                           // assert(dynamic_cast<Foo>) etc.
117
118     /** Indicates the size of the request. */
119    int size;
120
121    /** A index of the source of the transaction. */
122    short src;
123
124    static const short Broadcast = -1;
125
126    /** A index to the destination of the transaction. */
127    short dest;
128
129    /** The command of the transaction. */
130    Command cmd;
131
132    /** The time this request was responded to. Used to calculate latencies. */
133    Tick time;
134
135    /** The result of the packet transaction. */
136    PacketResult result;
137
138    /** Accessor function that returns the source index of the packet. */
139    short getSrc() const { return src; }
140
141    /** Accessor function that returns the destination index of
142        the packet. */
143    short getDest() const { return dest; }
144
145    Packet()
146        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
147           time(curTick), result(Unknown)
148        {}
149
150    ~Packet()
151    { deleteData(); }
152
153
154    /** Minimally reset a packet so something like simple cpu can reuse it. */
155    void reset();
156
157    /** Set the data pointer to the following value that should not be freed. */
158    template <typename T>
159    void dataStatic(T *p);
160
161    /** Set the data pointer to a value that should have delete [] called on it.
162     */
163    template <typename T>
164    void dataDynamicArray(T *p);
165
166    /** set the data pointer to a value that should have delete called on it. */
167    template <typename T>
168    void dataDynamic(T *p);
169
170    /** return the value of what is pointed to in the packet. */
171    template <typename T>
172    T get();
173
174    /** get a pointer to the data ptr. */
175    template <typename T>
176    T* getPtr();
177
178    /** set the value in the data pointer to v. */
179    template <typename T>
180    void set(T v);
181
182    /** delete the data pointed to in the data pointer. Ok to call to matter how
183     * data was allocted. */
184    void deleteData();
185
186    /** If there isn't data in the packet, allocate some. */
187    void allocate();
188
189    /** Do the packet modify the same addresses. */
190    bool intersect(Packet *p);
191};
192
193bool fixPacket(Packet *func, Packet *timing);
194#endif //__MEM_PACKET_HH
195