packet.hh revision 3207:0698f82cfbb3 
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 statistics we need max number of commands, hard code it at
62//20 for now.  @todo fix later
63#define NUM_MEM_CMDS 1 << 9
64
65/**
66 * A Packet is used to encapsulate a transfer between two objects in
67 * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
68 * single Request travels all the way from the requester to the
69 * ultimate destination and back, possibly being conveyed by several
70 * different Packets along the way.)
71 */
72class Packet
73{
74  public:
75    /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */
76    uint64_t flags;
77
78  private:
79   /** A pointer to the data being transfered.  It can be differnt
80    *    sizes at each level of the heirarchy so it belongs in the
81    *    packet, not request. This may or may not be populated when a
82    *    responder recieves the packet. If not populated it memory
83    *    should be allocated.
84    */
85    PacketDataPtr data;
86
87    /** Is the data pointer set to a value that shouldn't be freed
88     *   when the packet is destroyed? */
89    bool staticData;
90    /** The data pointer points to a value that should be freed when
91     *   the packet is destroyed. */
92    bool dynamicData;
93    /** the data pointer points to an array (thus delete [] ) needs to
94     *   be called on it rather than simply delete.*/
95    bool arrayData;
96
97
98    /** The address of the request.  This address could be virtual or
99     *   physical, depending on the system configuration. */
100    Addr addr;
101
102     /** The size of the request or transfer. */
103    int size;
104
105    /** Device address (e.g., bus ID) of the source of the
106     *   transaction. The source is not responsible for setting this
107     *   field; it is set implicitly by the interconnect when the
108     *   packet * is first sent.  */
109    short src;
110
111    /** Device address (e.g., bus ID) of the destination of the
112     *   transaction. The special value Broadcast indicates that the
113     *   packet should be routed based on its address. This field is
114     *   initialized in the constructor and is thus always valid
115     *   (unlike * addr, size, and src). */
116    short dest;
117
118    /** Are the 'addr' and 'size' fields valid? */
119    bool addrSizeValid;
120    /** Is the 'src' field valid? */
121    bool srcValid;
122
123
124  public:
125
126    /** Used to calculate latencies for each packet.*/
127    Tick time;
128
129    /** The special destination address indicating that the packet
130     *   should be routed based on its address. */
131    static const short Broadcast = -1;
132
133    /** A pointer to the original request. */
134    RequestPtr req;
135
136    /** A virtual base opaque structure used to hold coherence-related
137     *    state.  A specific subclass would be derived from this to
138     *    carry state specific to a particular coherence protocol.  */
139    class CoherenceState {
140      public:
141        virtual ~CoherenceState() {}
142    };
143
144    /** This packet's coherence state.  Caches should use
145     *   dynamic_cast<> to cast to the state appropriate for the
146     *   system's coherence protocol.  */
147    CoherenceState *coherence;
148
149    /** A virtual base opaque structure used to hold state associated
150     *    with the packet but specific to the sending device (e.g., an
151     *    MSHR).  A pointer to this state is returned in the packet's
152     *    response so that the sender can quickly look up the state
153     *    needed to process it.  A specific subclass would be derived
154     *    from this to carry state specific to a particular sending
155     *    device.  */
156    class SenderState {
157      public:
158        virtual ~SenderState() {}
159    };
160
161    /** This packet's sender state.  Devices should use dynamic_cast<>
162     *   to cast to the state appropriate to the sender. */
163    SenderState *senderState;
164
165  private:
166    /** List of command attributes. */
167    enum CommandAttribute
168    {
169        IsRead		= 1 << 0,
170        IsWrite		= 1 << 1,
171        IsPrefetch	= 1 << 2,
172        IsInvalidate	= 1 << 3,
173        IsRequest	= 1 << 4,
174        IsResponse 	= 1 << 5,
175        NeedsResponse	= 1 << 6,
176        IsSWPrefetch    = 1 << 7,
177        IsHWPrefetch    = 1 << 8,
178        IsUpgrade       = 1 << 9
179    };
180
181  public:
182    /** List of all commands associated with a packet. */
183    enum Command
184    {
185        InvalidCmd      = 0,
186        ReadReq		= IsRead  | IsRequest | NeedsResponse,
187        WriteReq	= IsWrite | IsRequest | NeedsResponse,
188        WriteReqNoAck	= IsWrite | IsRequest,
189        ReadResp	= IsRead  | IsResponse | NeedsResponse,
190        WriteResp	= IsWrite | IsResponse | NeedsResponse,
191        Writeback       = IsWrite | IsRequest,
192        SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
193        HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
194        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch | NeedsResponse,
195        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch | NeedsResponse,
196        InvalidateReq   = IsInvalidate | IsRequest,
197        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest,
198        UpgradeReq      = IsInvalidate | IsRequest | IsUpgrade,
199        ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
200        ReadExResp      = IsRead | IsInvalidate | IsResponse | NeedsResponse
201    };
202
203    /** Return the string name of the cmd field (for debugging and
204     *   tracing). */
205    const std::string &cmdString() const;
206
207    /** Reutrn the string to a cmd given by idx. */
208    const std::string &cmdIdxToString(Command idx);
209
210    /** Return the index of this command. */
211    inline int cmdToIndex() const { return (int) cmd; }
212
213    /** The command field of the packet. */
214    Command cmd;
215
216    bool isRead() 	 { return (cmd & IsRead)  != 0; }
217    bool isWrite()       { return (cmd & IsWrite) != 0; }
218    bool isRequest()	 { return (cmd & IsRequest)  != 0; }
219    bool isResponse()	 { return (cmd & IsResponse) != 0; }
220    bool needsResponse() { return (cmd & NeedsResponse) != 0; }
221    bool isInvalidate()  { return (cmd & IsInvalidate) != 0; }
222
223    bool isCacheFill() { return (flags & CACHE_LINE_FILL) != 0; }
224    bool isNoAllocate() { return (flags & NO_ALLOCATE) != 0; }
225    bool isCompressed() { return (flags & COMPRESSED) != 0; }
226
227    bool nic_pkt() { assert("Unimplemented\n" && 0); return false; }
228
229    /** Possible results of a packet's request. */
230    enum Result
231    {
232        Success,
233        BadAddress,
234        Nacked,
235        Unknown
236    };
237
238    /** The result of this packet's request. */
239    Result result;
240
241    /** Accessor function that returns the source index of the packet. */
242    short getSrc() const { assert(srcValid); return src; }
243    void setSrc(short _src) { src = _src; srcValid = true; }
244
245    /** Accessor function that returns the destination index of
246        the packet. */
247    short getDest() const { return dest; }
248    void setDest(short _dest) { dest = _dest; }
249
250    Addr getAddr() const { assert(addrSizeValid); return addr; }
251    int getSize() const { assert(addrSizeValid); return size; }
252    Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
253
254    void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
255    void cmdOverride(Command newCmd) { cmd = newCmd; }
256
257    /** Constructor.  Note that a Request object must be constructed
258     *   first, but the Requests's physical address and size fields
259     *   need not be valid. The command and destination addresses
260     *   must be supplied.  */
261    Packet(Request *_req, Command _cmd, short _dest)
262        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
263           addr(_req->paddr), size(_req->size), dest(_dest),
264           addrSizeValid(_req->validPaddr),
265           srcValid(false),
266           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
267           result(Unknown)
268    {
269        flags = 0;
270        time = curTick;
271    }
272
273    /** Alternate constructor if you are trying to create a packet with
274     *  a request that is for a whole block, not the address from the req.
275     *  this allows for overriding the size/addr of the req.*/
276    Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
277        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
278           addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
279           dest(_dest),
280           addrSizeValid(_req->validPaddr), srcValid(false),
281           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
282           result(Unknown)
283    {
284        flags = 0;
285        time = curTick;
286    }
287
288    /** Destructor. */
289    ~Packet()
290    { deleteData(); }
291
292    /** Reinitialize packet address and size from the associated
293     *   Request object, and reset other fields that may have been
294     *   modified by a previous transaction.  Typically called when a
295     *   statically allocated Request/Packet pair is reused for
296     *   multiple transactions. */
297    void reinitFromRequest() {
298        assert(req->validPaddr);
299        addr = req->paddr;
300        size = req->size;
301        time = req->time;
302        addrSizeValid = true;
303        result = Unknown;
304        if (dynamicData) {
305            deleteData();
306            dynamicData = false;
307            arrayData = false;
308        }
309    }
310
311    /** Take a request packet and modify it in place to be suitable
312     *   for returning as a response to that request.  Used for timing
313     *   accesses only.  For atomic and functional accesses, the
314     *   request packet is always implicitly passed back *without*
315     *   modifying the destination fields, so this function
316     *   should not be called. */
317    void makeTimingResponse() {
318        assert(needsResponse());
319        assert(isRequest());
320        int icmd = (int)cmd;
321        icmd &= ~(IsRequest);
322        icmd |= IsResponse;
323        cmd = (Command)icmd;
324        dest = src;
325        srcValid = false;
326    }
327
328    /** Take a request packet and modify it in place to be suitable
329     *   for returning as a response to that request.
330     */
331    void makeAtomicResponse() {
332        assert(needsResponse());
333        assert(isRequest());
334        int icmd = (int)cmd;
335        icmd &= ~(IsRequest);
336        icmd |= IsResponse;
337        cmd = (Command)icmd;
338    }
339
340    /** Take a request packet that has been returned as NACKED and modify it so
341     * that it can be sent out again. Only packets that need a response can be
342     * NACKED, so verify that that is true. */
343    void reinitNacked() {
344        assert(needsResponse() && result == Nacked);
345        dest =  Broadcast;
346        result = Unknown;
347    }
348
349
350    /** Set the data pointer to the following value that should not be freed. */
351    template <typename T>
352    void dataStatic(T *p);
353
354    /** Set the data pointer to a value that should have delete [] called on it.
355     */
356    template <typename T>
357    void dataDynamicArray(T *p);
358
359    /** set the data pointer to a value that should have delete called on it. */
360    template <typename T>
361    void dataDynamic(T *p);
362
363    /** return the value of what is pointed to in the packet. */
364    template <typename T>
365    T get();
366
367    /** get a pointer to the data ptr. */
368    template <typename T>
369    T* getPtr();
370
371    /** set the value in the data pointer to v. */
372    template <typename T>
373    void set(T v);
374
375    /** delete the data pointed to in the data pointer. Ok to call to matter how
376     * data was allocted. */
377    void deleteData();
378
379    /** If there isn't data in the packet, allocate some. */
380    void allocate();
381
382    /** Do the packet modify the same addresses. */
383    bool intersect(Packet *p);
384};
385
386bool fixPacket(Packet *func, Packet *timing);
387#endif //__MEM_PACKET_HH
388