packet.hh revision 2980:eab855f06b79 
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
46struct Packet;
47typedef Packet* PacketPtr;
48typedef uint8_t* PacketDataPtr;
49typedef std::list<PacketPtr> PacketList;
50
51//Coherence Flags
52#define NACKED_LINE 1 << 0
53#define SATISFIED 1 << 1
54#define SHARED_LINE 1 << 2
55#define CACHE_LINE_FILL 1 << 3
56#define COMPRESSED 1 << 4
57#define NO_ALLOCATE 1 << 5
58
59//For statistics we need max number of commands, hard code it at
60//20 for now.  @todo fix later
61#define NUM_MEM_CMDS 1 << 9
62
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
96    /** The address of the request.  This address could be virtual or
97     *   physical, depending on the system configuration. */
98    Addr addr;
99
100     /** The size of the request or transfer. */
101    int size;
102
103    /** Device address (e.g., bus ID) of the source of the
104     *   transaction. The source is not responsible for setting this
105     *   field; it is set implicitly by the interconnect when the
106     *   packet * is first sent.  */
107    short src;
108
109    /** Device address (e.g., bus ID) of the destination of the
110     *   transaction. The special value Broadcast indicates that the
111     *   packet should be routed based on its address. This field is
112     *   initialized in the constructor and is thus always valid
113     *   (unlike * addr, size, and src). */
114    short dest;
115
116    /** Are the 'addr' and 'size' fields valid? */
117    bool addrSizeValid;
118    /** Is the 'src' field valid? */
119    bool srcValid;
120
121
122  public:
123
124    /** Used to calculate latencies for each packet.*/
125    Tick time;
126
127    /** The special destination address indicating that the packet
128     *   should be routed based on its address. */
129    static const short Broadcast = -1;
130
131    /** A pointer to the original request. */
132    RequestPtr req;
133
134    /** A virtual base opaque structure used to hold coherence-related
135     *    state.  A specific subclass would be derived from this to
136     *    carry state specific to a particular coherence protocol.  */
137    class CoherenceState {
138      public:
139        virtual ~CoherenceState() {}
140    };
141
142    /** This packet's coherence state.  Caches should use
143     *   dynamic_cast<> to cast to the state appropriate for the
144     *   system's coherence protocol.  */
145    CoherenceState *coherence;
146
147    /** A virtual base opaque structure used to hold state associated
148     *    with the packet but specific to the sending device (e.g., an
149     *    MSHR).  A pointer to this state is returned in the packet's
150     *    response so that the sender can quickly look up the state
151     *    needed to process it.  A specific subclass would be derived
152     *    from this to carry state specific to a particular sending
153     *    device.  */
154    class SenderState {
155      public:
156        virtual ~SenderState() {}
157    };
158
159    /** This packet's sender state.  Devices should use dynamic_cast<>
160     *   to cast to the state appropriate to the sender. */
161    SenderState *senderState;
162
163  private:
164    /** List of command attributes. */
165    enum CommandAttribute
166    {
167        IsRead		= 1 << 0,
168        IsWrite		= 1 << 1,
169        IsPrefetch	= 1 << 2,
170        IsInvalidate	= 1 << 3,
171        IsRequest	= 1 << 4,
172        IsResponse 	= 1 << 5,
173        NeedsResponse	= 1 << 6,
174        IsSWPrefetch    = 1 << 7,
175        IsHWPrefetch    = 1 << 8
176    };
177
178  public:
179    /** List of all commands associated with a packet. */
180    enum Command
181    {
182        InvalidCmd      = 0,
183        ReadReq		= IsRead  | IsRequest | NeedsResponse,
184        WriteReq	= IsWrite | IsRequest | NeedsResponse,
185        WriteReqNoAck	= IsWrite | IsRequest,
186        ReadResp	= IsRead  | IsResponse | NeedsResponse,
187        WriteResp	= IsWrite | IsResponse | NeedsResponse,
188        Writeback       = IsWrite | IsRequest,
189        SoftPFReq       = IsRead  | IsRequest | IsSWPrefetch | NeedsResponse,
190        HardPFReq       = IsRead  | IsRequest | IsHWPrefetch | NeedsResponse,
191        SoftPFResp      = IsRead  | IsResponse | IsSWPrefetch | NeedsResponse,
192        HardPFResp      = IsRead  | IsResponse | IsHWPrefetch | NeedsResponse,
193        InvalidateReq   = IsInvalidate | IsRequest,
194        WriteInvalidateReq = IsWrite | IsInvalidate | IsRequest,
195        UpgradeReq      = IsInvalidate | IsRequest | NeedsResponse,
196        UpgradeResp     = IsInvalidate | IsResponse | NeedsResponse,
197        ReadExReq       = IsRead | IsInvalidate | IsRequest | NeedsResponse,
198        ReadExResp      = IsRead | IsInvalidate | IsResponse | NeedsResponse
199    };
200
201    /** Return the string name of the cmd field (for debugging and
202     *   tracing). */
203    const std::string &cmdString() const;
204
205    /** Reutrn the string to a cmd given by idx. */
206    const std::string &cmdIdxToString(Command idx);
207
208    /** Return the index of this command. */
209    inline int cmdToIndex() const { return (int) cmd; }
210
211    /** The command field of the packet. */
212    Command cmd;
213
214    bool isRead() 	 { return (cmd & IsRead)  != 0; }
215    bool isWrite()       { return (cmd & IsWrite) != 0; }
216    bool isRequest()	 { return (cmd & IsRequest)  != 0; }
217    bool isResponse()	 { return (cmd & IsResponse) != 0; }
218    bool needsResponse() { return (cmd & NeedsResponse) != 0; }
219    bool isInvalidate()  { return (cmd * IsInvalidate) != 0; }
220
221    bool isCacheFill() { return (flags & CACHE_LINE_FILL) != 0; }
222    bool isNoAllocate() { return (flags & NO_ALLOCATE) != 0; }
223    bool isCompressed() { return (flags & COMPRESSED) != 0; }
224
225    bool nic_pkt() { assert("Unimplemented\n" && 0); }
226
227    /** Possible results of a packet's request. */
228    enum Result
229    {
230        Success,
231        BadAddress,
232        Nacked,
233        Unknown
234    };
235
236    /** The result of this packet's request. */
237    Result result;
238
239    /** Accessor function that returns the source index of the packet. */
240    short getSrc() const { assert(srcValid); return src; }
241    void setSrc(short _src) { src = _src; srcValid = true; }
242
243    /** Accessor function that returns the destination index of
244        the packet. */
245    short getDest() const { return dest; }
246    void setDest(short _dest) { dest = _dest; }
247
248    Addr getAddr() const { assert(addrSizeValid); return addr; }
249    int getSize() const { assert(addrSizeValid); return size; }
250    Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
251
252    void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
253    void cmdOverride(Command newCmd) { cmd = newCmd; }
254
255    /** Constructor.  Note that a Request object must be constructed
256     *   first, but the Requests's physical address and size fields
257     *   need not be valid. The command and destination addresses
258     *   must be supplied.  */
259    Packet(Request *_req, Command _cmd, short _dest)
260        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
261           addr(_req->paddr), size(_req->size), dest(_dest),
262           addrSizeValid(_req->validPaddr),
263           srcValid(false),
264           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
265           result(Unknown)
266    {
267        flags = 0;
268    }
269
270    /** Alternate constructor if you are trying to create a packet with
271     *  a request that is for a whole block, not the address from the req.
272     *  this allows for overriding the size/addr of the req.*/
273    Packet(Request *_req, Command _cmd, short _dest, int _blkSize)
274        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
275           addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
276           dest(_dest),
277           addrSizeValid(_req->validPaddr), srcValid(false),
278           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
279           result(Unknown)
280    {
281        flags = 0;
282    }
283
284    /** Destructor. */
285    ~Packet()
286    { deleteData(); }
287
288    /** Reinitialize packet address and size from the associated
289     *   Request object, and reset other fields that may have been
290     *   modified by a previous transaction.  Typically called when a
291     *   statically allocated Request/Packet pair is reused for
292     *   multiple transactions. */
293    void reinitFromRequest() {
294        assert(req->validPaddr);
295        addr = req->paddr;
296        size = req->size;
297        addrSizeValid = true;
298        result = Unknown;
299        if (dynamicData) {
300            deleteData();
301            dynamicData = false;
302            arrayData = false;
303        }
304    }
305
306    /** Take a request packet and modify it in place to be suitable
307     *   for returning as a response to that request.  Used for timing
308     *   accesses only.  For atomic and functional accesses, the
309     *   request packet is always implicitly passed back *without*
310     *   modifying the command or destination fields, so this function
311     *   should not be called. */
312    void makeTimingResponse() {
313        assert(needsResponse());
314        assert(isRequest());
315        int icmd = (int)cmd;
316        icmd &= ~(IsRequest);
317        icmd |= IsResponse;
318        cmd = (Command)icmd;
319        dest = src;
320        srcValid = false;
321    }
322
323    /** Take a request packet that has been returned as NACKED and modify it so
324     * that it can be sent out again. Only packets that need a response can be
325     * NACKED, so verify that that is true. */
326    void reinitNacked() {
327        assert(needsResponse() && result == Nacked);
328        dest =  Broadcast;
329        result = Unknown;
330    }
331
332
333    /** Set the data pointer to the following value that should not be freed. */
334    template <typename T>
335    void dataStatic(T *p);
336
337    /** Set the data pointer to a value that should have delete [] called on it.
338     */
339    template <typename T>
340    void dataDynamicArray(T *p);
341
342    /** set the data pointer to a value that should have delete called on it. */
343    template <typename T>
344    void dataDynamic(T *p);
345
346    /** return the value of what is pointed to in the packet. */
347    template <typename T>
348    T get();
349
350    /** get a pointer to the data ptr. */
351    template <typename T>
352    T* getPtr();
353
354    /** set the value in the data pointer to v. */
355    template <typename T>
356    void set(T v);
357
358    /** delete the data pointed to in the data pointer. Ok to call to matter how
359     * data was allocted. */
360    void deleteData();
361
362    /** If there isn't data in the packet, allocate some. */
363    void allocate();
364
365    /** Do the packet modify the same addresses. */
366    bool intersect(Packet *p);
367};
368
369bool fixPacket(Packet *func, Packet *timing);
370#endif //__MEM_PACKET_HH
371