packet.hh revision 2989:9a6f66c38acc 
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 * Authors: Ron Dreslinski
29 *          Steve Reinhardt
30 *          Ali Saidi
31 */
32
33/**
34 * @file
35 * Declaration of the Packet class.
36 */
37
38#ifndef __MEM_PACKET_HH__
39#define __MEM_PACKET_HH__
40
41#include "mem/request.hh"
42#include "sim/host.hh"
43#include "sim/root.hh"
44#include <list>
45#include <cassert>
46
47struct Packet;
48typedef Packet* PacketPtr;
49typedef uint8_t* PacketDataPtr;
50typedef std::list<PacketPtr> PacketList;
51
52//Coherence Flags
53#define NACKED_LINE 1 << 0
54#define SATISFIED 1 << 1
55#define SHARED_LINE 1 << 2
56#define CACHE_LINE_FILL 1 << 3
57#define COMPRESSED 1 << 4
58#define NO_ALLOCATE 1 << 5
59
60//For statistics we need max number of commands, hard code it at
61//20 for now.  @todo fix later
62#define NUM_MEM_CMDS 1 << 9
63
64/**
65 * A Packet is used to encapsulate a transfer between two objects in
66 * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
67 * single Request travels all the way from the requester to the
68 * ultimate destination and back, possibly being conveyed by several
69 * different Packets along the way.)
70 */
71class Packet
72{
73  public:
74    /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */
75    uint64_t flags;
76
77  private:
78   /** A pointer to the data being transfered.  It can be differnt
79    *    sizes at each level of the heirarchy so it belongs in the
80    *    packet, not request. This may or may not be populated when a
81    *    responder recieves the packet. If not populated it memory
82    *    should be allocated.
83    */
84    PacketDataPtr data;
85
86    /** Is the data pointer set to a value that shouldn't be freed
87     *   when the packet is destroyed? */
88    bool staticData;
89    /** The data pointer points to a value that should be freed when
90     *   the packet is destroyed. */
91    bool dynamicData;
92    /** the data pointer points to an array (thus delete [] ) needs to
93     *   be called on it rather than simply delete.*/
94    bool arrayData;
95
96
97    /** The address of the request.  This address could be virtual or
98     *   physical, depending on the system configuration. */
99    Addr addr;
100
101     /** The size of the request or transfer. */
102    int size;
103
104    /** Device address (e.g., bus ID) of the source of the
105     *   transaction. The source is not responsible for setting this
106     *   field; it is set implicitly by the interconnect when the
107     *   packet * is first sent.  */
108    short src;
109
110    /** Device address (e.g., bus ID) of the destination of the
111     *   transaction. The special value Broadcast indicates that the
112     *   packet should be routed based on its address. This field is
113     *   initialized in the constructor and is thus always valid
114     *   (unlike * addr, size, and src). */
115    short dest;
116
117    /** Are the 'addr' and 'size' fields valid? */
118    bool addrSizeValid;
119    /** Is the 'src' field valid? */
120    bool srcValid;
121
122
123  public:
124
125    /** Used to calculate latencies for each packet.*/
126    Tick time;
127
128    /** The special destination address indicating that the packet
129     *   should be routed based on its address. */
130    static const short Broadcast = -1;
131
132    /** A pointer to the original request. */
133    RequestPtr req;
134
135    /** A virtual base opaque structure used to hold coherence-related
136     *    state.  A specific subclass would be derived from this to
137     *    carry state specific to a particular coherence protocol.  */
138    class CoherenceState {
139      public:
140        virtual ~CoherenceState() {}
141    };
142
143    /** This packet's coherence state.  Caches should use
144     *   dynamic_cast<> to cast to the state appropriate for the
145     *   system's coherence protocol.  */
146    CoherenceState *coherence;
147
148    /** A virtual base opaque structure used to hold state associated
149     *    with the packet but specific to the sending device (e.g., an
150     *    MSHR).  A pointer to this state is returned in the packet's
151     *    response so that the sender can quickly look up the state
152     *    needed to process it.  A specific subclass would be derived
153     *    from this to carry state specific to a particular sending
154     *    device.  */
155    class SenderState {
156      public:
157        virtual ~SenderState() {}
158    };
159
160    /** This packet's sender state.  Devices should use dynamic_cast<>
161     *   to cast to the state appropriate to the sender. */
162    SenderState *senderState;
163
164  private:
165    /** List of command attributes. */
166    enum CommandAttribute
167    {
168        IsRead		= 1 << 0,
169        IsWrite		= 1 << 1,
170        IsPrefetch	= 1 << 2,
171        IsInvalidate	= 1 << 3,
172        IsRequest	= 1 << 4,
173        IsResponse 	= 1 << 5,
174        NeedsResponse	= 1 << 6,
175        IsSWPrefetch    = 1 << 7,
176        IsHWPrefetch    = 1 << 8
177    };
178
179  public:
180    /** List of all commands associated with a packet. */
181    enum Command
182    {
183        InvalidCmd      = 0,
184        ReadReq		= IsRead  | IsRequest | NeedsResponse,
185        WriteReq	= IsWrite | IsRequest | NeedsResponse,
186        WriteReqNoAck	= IsWrite | IsRequest,
187        ReadResp	= IsRead  | IsResponse | NeedsResponse,
188        WriteResp	= IsWrite | IsResponse | NeedsResponse,
189        Writeback       = IsWrite | IsRequest,
190        SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
191        HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
192        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch | NeedsResponse,
193        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch | NeedsResponse,
194        InvalidateReq   = IsInvalidate | IsRequest,
195        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest,
196        UpgradeReq      = IsInvalidate | IsRequest | NeedsResponse,
197        UpgradeResp     = IsInvalidate | IsResponse | NeedsResponse,
198        ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
199        ReadExResp      = IsRead | IsInvalidate | IsResponse | NeedsResponse
200    };
201
202    /** Return the string name of the cmd field (for debugging and
203     *   tracing). */
204    const std::string &cmdString() const;
205
206    /** Reutrn the string to a cmd given by idx. */
207    const std::string &cmdIdxToString(Command idx);
208
209    /** Return the index of this command. */
210    inline int cmdToIndex() const { return (int) cmd; }
211
212    /** The command field of the packet. */
213    Command cmd;
214
215    bool isRead() 	 { return (cmd & IsRead)  != 0; }
216    bool isWrite()       { return (cmd & IsWrite) != 0; }
217    bool isRequest()	 { return (cmd & IsRequest)  != 0; }
218    bool isResponse()	 { return (cmd & IsResponse) != 0; }
219    bool needsResponse() { return (cmd & NeedsResponse) != 0; }
220    bool isInvalidate()  { return (cmd * IsInvalidate) != 0; }
221
222    bool isCacheFill() { return (flags & CACHE_LINE_FILL) != 0; }
223    bool isNoAllocate() { return (flags & NO_ALLOCATE) != 0; }
224    bool isCompressed() { return (flags & COMPRESSED) != 0; }
225
226    bool nic_pkt() { assert("Unimplemented\n" && 0); }
227
228    /** Possible results of a packet's request. */
229    enum Result
230    {
231        Success,
232        BadAddress,
233        Nacked,
234        Unknown
235    };
236
237    /** The result of this packet's request. */
238    Result result;
239
240    /** Accessor function that returns the source index of the packet. */
241    short getSrc() const { assert(srcValid); return src; }
242    void setSrc(short _src) { src = _src; srcValid = true; }
243
244    /** Accessor function that returns the destination index of
245        the packet. */
246    short getDest() const { return dest; }
247    void setDest(short _dest) { dest = _dest; }
248
249    Addr getAddr() const { assert(addrSizeValid); return addr; }
250    int getSize() const { assert(addrSizeValid); return size; }
251    Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
252
253    void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
254    void cmdOverride(Command newCmd) { cmd = newCmd; }
255
256    /** Constructor.  Note that a Request object must be constructed
257     *   first, but the Requests's physical address and size fields
258     *   need not be valid. The command and destination addresses
259     *   must be supplied.  */
260    Packet(Request *_req, Command _cmd, short _dest)
261        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
262           addr(_req->paddr), size(_req->size), dest(_dest),
263           addrSizeValid(_req->validPaddr),
264           srcValid(false),
265           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
266           result(Unknown)
267    {
268        flags = 0;
269    }
270
271    /** Alternate constructor if you are trying to create a packet with
272     *  a request that is for a whole block, not the address from the req.
273     *  this allows for overriding the size/addr of the req.*/
274    Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
275        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
276           addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
277           dest(_dest),
278           addrSizeValid(_req->validPaddr), srcValid(false),
279           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
280           result(Unknown)
281    {
282        flags = 0;
283    }
284
285    /** Destructor. */
286    ~Packet()
287    { deleteData(); }
288
289    /** Reinitialize packet address and size from the associated
290     *   Request object, and reset other fields that may have been
291     *   modified by a previous transaction.  Typically called when a
292     *   statically allocated Request/Packet pair is reused for
293     *   multiple transactions. */
294    void reinitFromRequest() {
295        assert(req->validPaddr);
296        addr = req->paddr;
297        size = req->size;
298        addrSizeValid = true;
299        result = Unknown;
300        if (dynamicData) {
301            deleteData();
302            dynamicData = false;
303            arrayData = false;
304        }
305    }
306
307    /** Take a request packet and modify it in place to be suitable
308     *   for returning as a response to that request.  Used for timing
309     *   accesses only.  For atomic and functional accesses, the
310     *   request packet is always implicitly passed back *without*
311     *   modifying the command or destination fields, so this function
312     *   should not be called. */
313    void makeTimingResponse() {
314        assert(needsResponse());
315        assert(isRequest());
316        int icmd = (int)cmd;
317        icmd &= ~(IsRequest);
318        icmd |= IsResponse;
319        cmd = (Command)icmd;
320        dest = src;
321        srcValid = false;
322    }
323
324    /** Take a request packet that has been returned as NACKED and modify it so
325     * that it can be sent out again. Only packets that need a response can be
326     * NACKED, so verify that that is true. */
327    void reinitNacked() {
328        assert(needsResponse() && result == Nacked);
329        dest =  Broadcast;
330        result = Unknown;
331    }
332
333
334    /** Set the data pointer to the following value that should not be freed. */
335    template <typename T>
336    void dataStatic(T *p);
337
338    /** Set the data pointer to a value that should have delete [] called on it.
339     */
340    template <typename T>
341    void dataDynamicArray(T *p);
342
343    /** set the data pointer to a value that should have delete called on it. */
344    template <typename T>
345    void dataDynamic(T *p);
346
347    /** return the value of what is pointed to in the packet. */
348    template <typename T>
349    T get();
350
351    /** get a pointer to the data ptr. */
352    template <typename T>
353    T* getPtr();
354
355    /** set the value in the data pointer to v. */
356    template <typename T>
357    void set(T v);
358
359    /** delete the data pointed to in the data pointer. Ok to call to matter how
360     * data was allocted. */
361    void deleteData();
362
363    /** If there isn't data in the packet, allocate some. */
364    void allocate();
365
366    /** Do the packet modify the same addresses. */
367    bool intersect(Packet *p);
368};
369
370bool fixPacket(Packet *func, Packet *timing);
371#endif //__MEM_PACKET_HH
372