packet.hh revision 3293:4ac3d9486d6e 
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#define SNOOP_COMMIT 1 << 6
60
61//for now.  @todo fix later
62#define NUM_MEM_CMDS 1 << 11
63/**
64 * A Packet is used to encapsulate a transfer between two objects in
65 * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
66 * single Request travels all the way from the requester to the
67 * ultimate destination and back, possibly being conveyed by several
68 * different Packets along the way.)
69 */
70class Packet
71{
72  public:
73    /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */
74    uint64_t flags;
75
76  private:
77   /** A pointer to the data being transfered.  It can be differnt
78    *    sizes at each level of the heirarchy so it belongs in the
79    *    packet, not request. This may or may not be populated when a
80    *    responder recieves the packet. If not populated it memory
81    *    should be allocated.
82    */
83    PacketDataPtr data;
84
85    /** Is the data pointer set to a value that shouldn't be freed
86     *   when the packet is destroyed? */
87    bool staticData;
88    /** The data pointer points to a value that should be freed when
89     *   the packet is destroyed. */
90    bool dynamicData;
91    /** the data pointer points to an array (thus delete [] ) needs to
92     *   be called on it rather than simply delete.*/
93    bool arrayData;
94
95    /** The address of the request.  This address could be virtual or
96     *   physical, depending on the system configuration. */
97    Addr addr;
98
99     /** The size of the request or transfer. */
100    int size;
101
102    /** Device address (e.g., bus ID) of the source of the
103     *   transaction. The source is not responsible for setting this
104     *   field; it is set implicitly by the interconnect when the
105     *   packet * is first sent.  */
106    short src;
107
108    /** Device address (e.g., bus ID) of the destination of the
109     *   transaction. The special value Broadcast indicates that the
110     *   packet should be routed based on its address. This field is
111     *   initialized in the constructor and is thus always valid
112     *   (unlike * addr, size, and src). */
113    short dest;
114
115    /** Are the 'addr' and 'size' fields valid? */
116    bool addrSizeValid;
117    /** Is the 'src' field valid? */
118    bool srcValid;
119
120
121  public:
122
123    /** Used to calculate latencies for each packet.*/
124    Tick time;
125
126    /** The time at which the packet will be fully transmitted */
127    Tick finishTime;
128
129    /** The time at which the first chunk of the packet will be transmitted */
130    Tick firstWordTime;
131
132    /** The special destination address indicating that the packet
133     *   should be routed based on its address. */
134    static const short Broadcast = -1;
135
136    /** A pointer to the original request. */
137    RequestPtr req;
138
139    /** A virtual base opaque structure used to hold coherence-related
140     *    state.  A specific subclass would be derived from this to
141     *    carry state specific to a particular coherence protocol.  */
142    class CoherenceState {
143      public:
144        virtual ~CoherenceState() {}
145    };
146
147    /** This packet's coherence state.  Caches should use
148     *   dynamic_cast<> to cast to the state appropriate for the
149     *   system's coherence protocol.  */
150    CoherenceState *coherence;
151
152    /** A virtual base opaque structure used to hold state associated
153     *    with the packet but specific to the sending device (e.g., an
154     *    MSHR).  A pointer to this state is returned in the packet's
155     *    response so that the sender can quickly look up the state
156     *    needed to process it.  A specific subclass would be derived
157     *    from this to carry state specific to a particular sending
158     *    device.  */
159    class SenderState {
160      public:
161        virtual ~SenderState() {}
162    };
163
164    /** This packet's sender state.  Devices should use dynamic_cast<>
165     *   to cast to the state appropriate to the sender. */
166    SenderState *senderState;
167
168  private:
169    /** List of command attributes. */
170    // If you add a new CommandAttribute, make sure to increase NUM_MEM_CMDS
171    // as well.
172    enum CommandAttribute
173    {
174        IsRead                = 1 << 0,
175        IsWrite                = 1 << 1,
176        IsPrefetch        = 1 << 2,
177        IsInvalidate        = 1 << 3,
178        IsRequest        = 1 << 4,
179        IsResponse         = 1 << 5,
180        NeedsResponse        = 1 << 6,
181        IsSWPrefetch    = 1 << 7,
182        IsHWPrefetch    = 1 << 8,
183        IsUpgrade       = 1 << 9,
184        HasData                = 1 << 10
185    };
186
187  public:
188    /** List of all commands associated with a packet. */
189    enum Command
190    {
191        InvalidCmd      = 0,
192        ReadReq                = IsRead  | IsRequest | NeedsResponse,
193        WriteReq        = IsWrite | IsRequest | NeedsResponse | HasData,
194        WriteReqNoAck        = IsWrite | IsRequest | HasData,
195        ReadResp        = IsRead  | IsResponse | NeedsResponse | HasData,
196        WriteResp        = IsWrite | IsResponse | NeedsResponse,
197        Writeback       = IsWrite | IsRequest | HasData,
198        SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
199        HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
200        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch
201                                | NeedsResponse | HasData,
202        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch
203                                    | NeedsResponse | HasData,
204        InvalidateReq   = IsInvalidate | IsRequest,
205        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest
206                                   | HasData | NeedsResponse,
207        WriteInvalidateResp = IsWrite | IsInvalidate | IsRequest | NeedsResponse,
208        UpgradeReq      = IsInvalidate | IsRequest | IsUpgrade,
209        ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
210        ReadExResp      = IsRead | IsInvalidate | IsResponse
211                                | NeedsResponse | HasData
212    };
213
214    /** Return the string name of the cmd field (for debugging and
215     *   tracing). */
216    const std::string &cmdString() const;
217
218    /** Reutrn the string to a cmd given by idx. */
219    const std::string &cmdIdxToString(Command idx);
220
221    /** Return the index of this command. */
222    inline int cmdToIndex() const { return (int) cmd; }
223
224    /** The command field of the packet. */
225    Command cmd;
226
227    bool isRead() const         { return (cmd & IsRead)  != 0; }
228    bool isWrite()  const       { return (cmd & IsWrite) != 0; }
229    bool isRequest() const      { return (cmd & IsRequest)  != 0; }
230    bool isResponse() const     { return (cmd & IsResponse) != 0; }
231    bool needsResponse() const  { return (cmd & NeedsResponse) != 0; }
232    bool isInvalidate() const   { return (cmd & IsInvalidate) != 0; }
233    bool hasData() const        { return (cmd & HasData) != 0; }
234
235    bool isCacheFill() const    { return (flags & CACHE_LINE_FILL) != 0; }
236    bool isNoAllocate() const   { return (flags & NO_ALLOCATE) != 0; }
237    bool isCompressed() const   { return (flags & COMPRESSED) != 0; }
238
239    bool nic_pkt() { assert("Unimplemented\n" && 0); return false; }
240
241    /** Possible results of a packet's request. */
242    enum Result
243    {
244        Success,
245        BadAddress,
246        Nacked,
247        Unknown
248    };
249
250    /** The result of this packet's request. */
251    Result result;
252
253    /** Accessor function that returns the source index of the packet. */
254    short getSrc() const { assert(srcValid); return src; }
255    void setSrc(short _src) { src = _src; srcValid = true; }
256
257    /** Accessor function that returns the destination index of
258        the packet. */
259    short getDest() const { return dest; }
260    void setDest(short _dest) { dest = _dest; }
261
262    Addr getAddr() const { assert(addrSizeValid); return addr; }
263    int getSize() const { assert(addrSizeValid); return size; }
264    Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
265
266    void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
267    void cmdOverride(Command newCmd) { cmd = newCmd; }
268
269    /** Constructor.  Note that a Request object must be constructed
270     *   first, but the Requests's physical address and size fields
271     *   need not be valid. The command and destination addresses
272     *   must be supplied.  */
273    Packet(Request *_req, Command _cmd, short _dest)
274        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
275           addr(_req->paddr), size(_req->size), dest(_dest),
276           addrSizeValid(_req->validPaddr),
277           srcValid(false),
278           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
279           result(Unknown)
280    {
281        flags = 0;
282        time = curTick;
283    }
284
285    /** Alternate constructor if you are trying to create a packet with
286     *  a request that is for a whole block, not the address from the req.
287     *  this allows for overriding the size/addr of the req.*/
288    Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
289        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
290           addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
291           dest(_dest),
292           addrSizeValid(_req->validPaddr), srcValid(false),
293           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
294           result(Unknown)
295    {
296        flags = 0;
297        time = curTick;
298    }
299
300    /** Destructor. */
301    ~Packet()
302    { deleteData(); }
303
304    /** Reinitialize packet address and size from the associated
305     *   Request object, and reset other fields that may have been
306     *   modified by a previous transaction.  Typically called when a
307     *   statically allocated Request/Packet pair is reused for
308     *   multiple transactions. */
309    void reinitFromRequest() {
310        assert(req->validPaddr);
311        addr = req->paddr;
312        size = req->size;
313        time = req->time;
314        addrSizeValid = true;
315        result = Unknown;
316        if (dynamicData) {
317            deleteData();
318            dynamicData = false;
319            arrayData = false;
320        }
321    }
322
323    /** Take a request packet and modify it in place to be suitable
324     *   for returning as a response to that request.  Used for timing
325     *   accesses only.  For atomic and functional accesses, the
326     *   request packet is always implicitly passed back *without*
327     *   modifying the destination fields, so this function
328     *   should not be called. */
329    void makeTimingResponse() {
330        assert(needsResponse());
331        assert(isRequest());
332        int icmd = (int)cmd;
333        icmd &= ~(IsRequest);
334        icmd |= IsResponse;
335        if (isRead())
336            icmd |= HasData;
337        if (isWrite())
338            icmd &= ~HasData;
339        cmd = (Command)icmd;
340        dest = src;
341        srcValid = false;
342    }
343
344    /** Take a request packet and modify it in place to be suitable
345     *   for returning as a response to that request.
346     */
347    void makeAtomicResponse() {
348        assert(needsResponse());
349        assert(isRequest());
350        int icmd = (int)cmd;
351        icmd &= ~(IsRequest);
352        icmd |= IsResponse;
353        if (isRead())
354            icmd |= HasData;
355        if (isWrite())
356            icmd &= ~HasData;
357        cmd = (Command)icmd;
358    }
359
360    /** Take a request packet that has been returned as NACKED and modify it so
361     * that it can be sent out again. Only packets that need a response can be
362     * NACKED, so verify that that is true. */
363    void reinitNacked() {
364        assert(needsResponse() && result == Nacked);
365        dest =  Broadcast;
366        result = Unknown;
367    }
368
369
370    /** Set the data pointer to the following value that should not be freed. */
371    template <typename T>
372    void dataStatic(T *p);
373
374    /** Set the data pointer to a value that should have delete [] called on it.
375     */
376    template <typename T>
377    void dataDynamicArray(T *p);
378
379    /** set the data pointer to a value that should have delete called on it. */
380    template <typename T>
381    void dataDynamic(T *p);
382
383    /** return the value of what is pointed to in the packet. */
384    template <typename T>
385    T get();
386
387    /** get a pointer to the data ptr. */
388    template <typename T>
389    T* getPtr();
390
391    /** set the value in the data pointer to v. */
392    template <typename T>
393    void set(T v);
394
395    /** delete the data pointed to in the data pointer. Ok to call to matter how
396     * data was allocted. */
397    void deleteData();
398
399    /** If there isn't data in the packet, allocate some. */
400    void allocate();
401
402    /** Do the packet modify the same addresses. */
403    bool intersect(Packet *p);
404};
405
406
407/** This function given a functional packet and a timing packet either satisfies
408 * the timing packet, or updates the timing packet to reflect the updated state
409 * in the timing packet. It returns if the functional packet should continue to
410 * traverse the memory hierarchy or not.
411 */
412bool fixPacket(Packet *func, Packet *timing);
413
414std::ostream & operator<<(std::ostream &o, const Packet &p);
415
416#endif //__MEM_PACKET_HH
417