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
29/**
30 * @file
31 * Declaration of the Packet class.
32 */
33
34#ifndef __MEM_PACKET_HH__
35#define __MEM_PACKET_HH__
36
37#include "mem/request.hh"
38#include "arch/isa_traits.hh"
39#include "sim/root.hh"
40
41struct Packet;
42typedef Packet* PacketPtr;
43typedef uint8_t* PacketDataPtr;
44
45/**
46 * A Packet is used to encapsulate a transfer between two objects in
47 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
48 * single Request travels all the way from the requester to the
49 * ultimate destination and back, possibly being conveyed by several
50 * different Packets along the way.)
51 */
52class Packet
53{
54 private:
55 /** A pointer to the data being transfered. It can be differnt
56 * sizes at each level of the heirarchy so it belongs in the
57 * packet, not request. This may or may not be populated when a
58 * responder recieves the packet. If not populated it memory
59 * should be allocated.
60 */
61 PacketDataPtr data;
62
63 /** Is the data pointer set to a value that shouldn't be freed
64 * when the packet is destroyed? */
65 bool staticData;
66 /** The data pointer points to a value that should be freed when
67 * the packet is destroyed. */
68 bool dynamicData;
69 /** the data pointer points to an array (thus delete [] ) needs to
70 * be called on it rather than simply delete.*/
71 bool arrayData;
72
73
74 /** The address of the request. This address could be virtual or
75 * physical, depending on the system configuration. */
76 Addr addr;
77
78 /** The size of the request or transfer. */
79 int size;
80
81 /** Device address (e.g., bus ID) of the source of the
82 * transaction. The source is not responsible for setting this
83 * field; it is set implicitly by the interconnect when the
84 * packet * is first sent. */
85 short src;
86
87 /** Device address (e.g., bus ID) of the destination of the
88 * transaction. The special value Broadcast indicates that the
89 * packet should be routed based on its address. This field is
90 * initialized in the constructor and is thus always valid
91 * (unlike * addr, size, and src). */
92 short dest;
93
94 /** Are the 'addr' and 'size' fields valid? */
95 bool addrSizeValid;
96 /** Is the 'src' field valid? */
97 bool srcValid;
98
99 public:
100
101 /** The special destination address indicating that the packet
102 * should be routed based on its address. */
103 static const short Broadcast = -1;
104
105 /** A pointer to the original request. */
106 RequestPtr req;
107
108 /** A virtual base opaque structure used to hold coherence-related
109 * state. A specific subclass would be derived from this to
110 * carry state specific to a particular coherence protocol. */
111 class CoherenceState {
112 public:
113 virtual ~CoherenceState() {}
114 };
115
116 /** This packet's coherence state. Caches should use
117 * dynamic_cast<> to cast to the state appropriate for the
118 * system's coherence protocol. */
119 CoherenceState *coherence;
120
121 /** A virtual base opaque structure used to hold state associated
122 * with the packet but specific to the sending device (e.g., an
123 * MSHR). A pointer to this state is returned in the packet's
124 * response so that the sender can quickly look up the state
125 * needed to process it. A specific subclass would be derived
126 * from this to carry state specific to a particular sending
127 * device. */
128 class SenderState {
129 public:
130 virtual ~SenderState() {}
131 };
132
133 /** This packet's sender state. Devices should use dynamic_cast<>
134 * to cast to the state appropriate to the sender. */
135 SenderState *senderState;
136
137 private:
138 /** List of command attributes. */
139 enum CommandAttribute
140 {
141 IsRead = 1 << 0,
142 IsWrite = 1 << 1,
143 IsPrefetch = 1 << 2,
144 IsInvalidate = 1 << 3,
145 IsRequest = 1 << 4,
146 IsResponse = 1 << 5,
147 NeedsResponse = 1 << 6,
148 };
149
150 public:
151 /** List of all commands associated with a packet. */
152 enum Command
153 {
154 ReadReq = IsRead | IsRequest | NeedsResponse,
155 WriteReq = IsWrite | IsRequest | NeedsResponse,
156 WriteReqNoAck = IsWrite | IsRequest,
157 ReadResp = IsRead | IsResponse,
158 WriteResp = IsWrite | IsResponse
159 };
160
161 /** Return the string name of the cmd field (for debugging and
162 * tracing). */
163 const std::string &cmdString() const;
164
165 /** The command field of the packet. */
166 Command cmd;
167
168 bool isRead() { return (cmd & IsRead) != 0; }
169 bool isRequest() { return (cmd & IsRequest) != 0; }
170 bool isResponse() { return (cmd & IsResponse) != 0; }
171 bool needsResponse() { return (cmd & NeedsResponse) != 0; }
172
173 /** Possible results of a packet's request. */
174 enum Result
175 {
176 Success,
177 BadAddress,
178 Unknown
179 };
180
181 /** The result of this packet's request. */
182 Result result;
183
184 /** Accessor function that returns the source index of the packet. */
185 short getSrc() const { assert(srcValid); return src; }
186 void setSrc(short _src) { src = _src; srcValid = true; }
187
188 /** Accessor function that returns the destination index of
189 the packet. */
190 short getDest() const { return dest; }
191 void setDest(short _dest) { dest = _dest; }
192
193 Addr getAddr() const { assert(addrSizeValid); return addr; }
194 int getSize() const { assert(addrSizeValid); return size; }
195
196 /** Constructor. Note that a Request object must be constructed
197 * first, but the Requests's physical address and size fields
198 * need not be valid. The command and destination addresses
199 * must be supplied. */
200 Packet(Request *_req, Command _cmd, short _dest)
201 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
202 addr(_req->paddr), size(_req->size), dest(_dest),
203 addrSizeValid(_req->validPaddr),
204 srcValid(false),
205 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
206 result(Unknown)
207 {
208 }
209
210 /** Destructor. */
211 ~Packet()
212 { deleteData(); }
213
214 /** Reinitialize packet address and size from the associated
215 * Request object, and reset other fields that may have been
216 * modified by a previous transaction. Typically called when a
217 * statically allocated Request/Packet pair is reused for
218 * multiple transactions. */
219 void reinitFromRequest() {
220 assert(req->validPaddr);
221 addr = req->paddr;
222 size = req->size;
223 addrSizeValid = true;
224 result = Unknown;
225 if (dynamicData) {
226 deleteData();
227 dynamicData = false;
228 arrayData = false;
229 }
230 }
231
232 /** Take a request packet and modify it in place to be suitable
233 * for returning as a response to that request. Used for timing
234 * accesses only. For atomic and functional accesses, the
235 * request packet is always implicitly passed back *without*
236 * modifying the command or destination fields, so this function
237 * should not be called. */
238 void makeTimingResponse() {
239 assert(needsResponse());
240 int icmd = (int)cmd;
241 icmd &= ~(IsRequest | NeedsResponse);
242 icmd |= IsResponse;
243 cmd = (Command)icmd;
244 dest = src;
245 srcValid = false;
246 }
247
248 /** Set the data pointer to the following value that should not be freed. */
249 template <typename T>
250 void dataStatic(T *p);
251
252 /** Set the data pointer to a value that should have delete [] called on it.
253 */
254 template <typename T>
255 void dataDynamicArray(T *p);
256
257 /** set the data pointer to a value that should have delete called on it. */
258 template <typename T>
259 void dataDynamic(T *p);
260
261 /** return the value of what is pointed to in the packet. */
262 template <typename T>
263 T get();
264
265 /** get a pointer to the data ptr. */
266 template <typename T>
267 T* getPtr();
268
269 /** set the value in the data pointer to v. */
270 template <typename T>
271 void set(T v);
272
273 /** delete the data pointed to in the data pointer. Ok to call to matter how
274 * data was allocted. */
275 void deleteData();
276
277 /** If there isn't data in the packet, allocate some. */
278 void allocate();
279
280 /** Do the packet modify the same addresses. */
281 bool intersect(Packet *p);
282};
283
284bool fixPacket(Packet *func, Packet *timing);
285#endif //__MEM_PACKET_HH