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.
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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 "arch/isa_traits.hh"
43#include "sim/root.hh"
44
45struct Packet;
46typedef Packet* PacketPtr;
47typedef uint8_t* PacketDataPtr;
48
49/**
50 * A Packet is used to encapsulate a transfer between two objects in
51 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
52 * single Request travels all the way from the requester to the
53 * ultimate destination and back, possibly being conveyed by several
54 * different Packets along the way.)
55 */
56class Packet
57{
58 private:
59 /** A pointer to the data being transfered. It can be differnt
60 * sizes at each level of the heirarchy so it belongs in the
61 * packet, not request. This may or may not be populated when a
62 * responder recieves the packet. If not populated it memory
63 * should be allocated.
64 */
65 PacketDataPtr data;
66
67 /** Is the data pointer set to a value that shouldn't be freed
68 * when the packet is destroyed? */
69 bool staticData;
70 /** The data pointer points to a value that should be freed when
71 * the packet is destroyed. */
72 bool dynamicData;
73 /** the data pointer points to an array (thus delete [] ) needs to
74 * be called on it rather than simply delete.*/
75 bool arrayData;
76
77
78 /** The address of the request. This address could be virtual or
79 * physical, depending on the system configuration. */
80 Addr addr;
81
82 /** The size of the request or transfer. */
83 int size;
84
85 /** Device address (e.g., bus ID) of the source of the
86 * transaction. The source is not responsible for setting this
87 * field; it is set implicitly by the interconnect when the
88 * packet * is first sent. */
89 short src;
90
91 /** Device address (e.g., bus ID) of the destination of the
92 * transaction. The special value Broadcast indicates that the
93 * packet should be routed based on its address. This field is
94 * initialized in the constructor and is thus always valid
95 * (unlike * addr, size, and src). */
96 short dest;
97
98 /** Are the 'addr' and 'size' fields valid? */
99 bool addrSizeValid;
100 /** Is the 'src' field valid? */
101 bool srcValid;
102
103 public:
104
105 /** The special destination address indicating that the packet
106 * should be routed based on its address. */
107 static const short Broadcast = -1;
108
109 /** A pointer to the original request. */
110 RequestPtr req;
111
112 /** A virtual base opaque structure used to hold coherence-related
113 * state. A specific subclass would be derived from this to
114 * carry state specific to a particular coherence protocol. */
115 class CoherenceState {
116 public:
117 virtual ~CoherenceState() {}
118 };
119
120 /** This packet's coherence state. Caches should use
121 * dynamic_cast<> to cast to the state appropriate for the
122 * system's coherence protocol. */
123 CoherenceState *coherence;
124
125 /** A virtual base opaque structure used to hold state associated
126 * with the packet but specific to the sending device (e.g., an
127 * MSHR). A pointer to this state is returned in the packet's
128 * response so that the sender can quickly look up the state
129 * needed to process it. A specific subclass would be derived
130 * from this to carry state specific to a particular sending
131 * device. */
132 class SenderState {
133 public:
134 virtual ~SenderState() {}
135 };
136
137 /** This packet's sender state. Devices should use dynamic_cast<>
138 * to cast to the state appropriate to the sender. */
139 SenderState *senderState;
140
141 private:
142 /** List of command attributes. */
143 enum CommandAttribute
144 {
145 IsRead = 1 << 0,
146 IsWrite = 1 << 1,
147 IsPrefetch = 1 << 2,
148 IsInvalidate = 1 << 3,
149 IsRequest = 1 << 4,
150 IsResponse = 1 << 5,
151 NeedsResponse = 1 << 6,
152 };
153
154 public:
155 /** List of all commands associated with a packet. */
156 enum Command
157 {
158 ReadReq = IsRead | IsRequest | NeedsResponse,
159 WriteReq = IsWrite | IsRequest | NeedsResponse,
160 WriteReqNoAck = IsWrite | IsRequest,
161 ReadResp = IsRead | IsResponse,
162 WriteResp = IsWrite | IsResponse
163 };
164
165 /** Return the string name of the cmd field (for debugging and
166 * tracing). */
167 const std::string &cmdString() const;
168
169 /** The command field of the packet. */
170 Command cmd;
171
172 bool isRead() { return (cmd & IsRead) != 0; }
173 bool isRequest() { return (cmd & IsRequest) != 0; }
174 bool isResponse() { return (cmd & IsResponse) != 0; }
175 bool needsResponse() { return (cmd & NeedsResponse) != 0; }
176
177 /** Possible results of a packet's request. */
178 enum Result
179 {
180 Success,
181 BadAddress,
182 Unknown
183 };
184
185 /** The result of this packet's request. */
186 Result result;
187
188 /** Accessor function that returns the source index of the packet. */
189 short getSrc() const { assert(srcValid); return src; }
190 void setSrc(short _src) { src = _src; srcValid = true; }
191
192 /** Accessor function that returns the destination index of
193 the packet. */
194 short getDest() const { return dest; }
195 void setDest(short _dest) { dest = _dest; }
196
197 Addr getAddr() const { assert(addrSizeValid); return addr; }
198 int getSize() const { assert(addrSizeValid); return size; }
199
200 /** Constructor. Note that a Request object must be constructed
201 * first, but the Requests's physical address and size fields
202 * need not be valid. The command and destination addresses
203 * must be supplied. */
204 Packet(Request *_req, Command _cmd, short _dest)
205 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
206 addr(_req->paddr), size(_req->size), dest(_dest),
207 addrSizeValid(_req->validPaddr),
208 srcValid(false),
209 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
210 result(Unknown)
211 {
212 }
213
214 /** Destructor. */
215 ~Packet()
216 { deleteData(); }
217
218 /** Reinitialize packet address and size from the associated
219 * Request object, and reset other fields that may have been
220 * modified by a previous transaction. Typically called when a
221 * statically allocated Request/Packet pair is reused for
222 * multiple transactions. */
223 void reinitFromRequest() {
224 assert(req->validPaddr);
225 addr = req->paddr;
226 size = req->size;
227 addrSizeValid = true;
228 result = Unknown;
229 if (dynamicData) {
230 deleteData();
231 dynamicData = false;
232 arrayData = false;
233 }
234 }
235
236 /** Take a request packet and modify it in place to be suitable
237 * for returning as a response to that request. Used for timing
238 * accesses only. For atomic and functional accesses, the
239 * request packet is always implicitly passed back *without*
240 * modifying the command or destination fields, so this function
241 * should not be called. */
242 void makeTimingResponse() {
243 assert(needsResponse());
244 int icmd = (int)cmd;
245 icmd &= ~(IsRequest | NeedsResponse);
246 icmd |= IsResponse;
247 cmd = (Command)icmd;
248 dest = src;
249 srcValid = false;
250 }
251
252 /** Set the data pointer to the following value that should not be freed. */
253 template <typename T>
254 void dataStatic(T *p);
255
256 /** Set the data pointer to a value that should have delete [] called on it.
257 */
258 template <typename T>
259 void dataDynamicArray(T *p);
260
261 /** set the data pointer to a value that should have delete called on it. */
262 template <typename T>
263 void dataDynamic(T *p);
264
265 /** return the value of what is pointed to in the packet. */
266 template <typename T>
267 T get();
268
269 /** get a pointer to the data ptr. */
270 template <typename T>
271 T* getPtr();
272
273 /** set the value in the data pointer to v. */
274 template <typename T>
275 void set(T v);
276
277 /** delete the data pointed to in the data pointer. Ok to call to matter how
278 * data was allocted. */
279 void deleteData();
280
281 /** If there isn't data in the packet, allocate some. */
282 void allocate();
283
284 /** Do the packet modify the same addresses. */
285 bool intersect(Packet *p);
286};
287
288bool fixPacket(Packet *func, Packet *timing);
289#endif //__MEM_PACKET_HH
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