packet.hh revision 3205:135273dc77a9 
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    };
179
180  public:
181    /** List of all commands associated with a packet. */
182    enum Command
183    {
184        InvalidCmd      = 0,
185        ReadReq		= IsRead  | IsRequest | NeedsResponse,
186        WriteReq	= IsWrite | IsRequest | NeedsResponse,
187        WriteReqNoAck	= IsWrite | IsRequest,
188        ReadResp	= IsRead  | IsResponse | NeedsResponse,
189        WriteResp	= IsWrite | IsResponse | NeedsResponse,
190        Writeback       = IsWrite | IsRequest,
191        SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
192        HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
193        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch | NeedsResponse,
194        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch | NeedsResponse,
195        InvalidateReq   = IsInvalidate | IsRequest,
196        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest,
197        UpgradeReq      = IsInvalidate | IsRequest
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); return false; }
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        time = curTick;
270    }
271
272    /** Alternate constructor if you are trying to create a packet with
273     *  a request that is for a whole block, not the address from the req.
274     *  this allows for overriding the size/addr of the req.*/
275    Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
276        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
277           addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
278           dest(_dest),
279           addrSizeValid(_req->validPaddr), srcValid(false),
280           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
281           result(Unknown)
282    {
283        flags = 0;
284        time = curTick;
285    }
286
287    /** Destructor. */
288    ~Packet()
289    { deleteData(); }
290
291    /** Reinitialize packet address and size from the associated
292     *   Request object, and reset other fields that may have been
293     *   modified by a previous transaction.  Typically called when a
294     *   statically allocated Request/Packet pair is reused for
295     *   multiple transactions. */
296    void reinitFromRequest() {
297        assert(req->validPaddr);
298        addr = req->paddr;
299        size = req->size;
300        time = req->time;
301        addrSizeValid = true;
302        result = Unknown;
303        if (dynamicData) {
304            deleteData();
305            dynamicData = false;
306            arrayData = false;
307        }
308    }
309
310    /** Take a request packet and modify it in place to be suitable
311     *   for returning as a response to that request.  Used for timing
312     *   accesses only.  For atomic and functional accesses, the
313     *   request packet is always implicitly passed back *without*
314     *   modifying the destination fields, so this function
315     *   should not be called. */
316    void makeTimingResponse() {
317        assert(needsResponse());
318        assert(isRequest());
319        int icmd = (int)cmd;
320        icmd &= ~(IsRequest);
321        icmd |= IsResponse;
322        cmd = (Command)icmd;
323        dest = src;
324        srcValid = false;
325    }
326
327    /** Take a request packet and modify it in place to be suitable
328     *   for returning as a response to that request.
329     */
330    void makeAtomicResponse() {
331        assert(needsResponse());
332        assert(isRequest());
333        int icmd = (int)cmd;
334        icmd &= ~(IsRequest);
335        icmd |= IsResponse;
336        cmd = (Command)icmd;
337    }
338
339    /** Take a request packet that has been returned as NACKED and modify it so
340     * that it can be sent out again. Only packets that need a response can be
341     * NACKED, so verify that that is true. */
342    void reinitNacked() {
343        assert(needsResponse() && result == Nacked);
344        dest =  Broadcast;
345        result = Unknown;
346    }
347
348
349    /** Set the data pointer to the following value that should not be freed. */
350    template <typename T>
351    void dataStatic(T *p);
352
353    /** Set the data pointer to a value that should have delete [] called on it.
354     */
355    template <typename T>
356    void dataDynamicArray(T *p);
357
358    /** set the data pointer to a value that should have delete called on it. */
359    template <typename T>
360    void dataDynamic(T *p);
361
362    /** return the value of what is pointed to in the packet. */
363    template <typename T>
364    T get();
365
366    /** get a pointer to the data ptr. */
367    template <typename T>
368    T* getPtr();
369
370    /** set the value in the data pointer to v. */
371    template <typename T>
372    void set(T v);
373
374    /** delete the data pointed to in the data pointer. Ok to call to matter how
375     * data was allocted. */
376    void deleteData();
377
378    /** If there isn't data in the packet, allocate some. */
379    void allocate();
380
381    /** Do the packet modify the same addresses. */
382    bool intersect(Packet *p);
383};
384
385bool fixPacket(Packet *func, Packet *timing);
386#endif //__MEM_PACKET_HH
387