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 <cassert>
42#include <list>
43#include <bitset>
44
45#include "base/compiler.hh"
46#include "base/misc.hh"
47#include "mem/request.hh"
48#include "sim/host.hh"
49#include "sim/root.hh"
50
51
52struct Packet;
53typedef Packet *PacketPtr;
54typedef uint8_t* PacketDataPtr;
55typedef std::list<PacketPtr> PacketList;
56
57//Coherence Flags
58#define NACKED_LINE (1 << 0)
59#define SATISFIED (1 << 1)
60#define SHARED_LINE (1 << 2)
61#define CACHE_LINE_FILL (1 << 3)
62#define COMPRESSED (1 << 4)
63#define NO_ALLOCATE (1 << 5)
64#define SNOOP_COMMIT (1 << 6)
65
66
67class MemCmd
68{
69 public:
70
71 /** List of all commands associated with a packet. */
72 enum Command
73 {
74 InvalidCmd,
75 ReadReq,
76 WriteReq,
77 WriteReqNoAck,
78 ReadResp,
79 WriteResp,
80 Writeback,
81 SoftPFReq,
82 HardPFReq,
83 SoftPFResp,
84 HardPFResp,
85 InvalidateReq,
86 WriteInvalidateReq,
87 WriteInvalidateResp,
88 UpgradeReq,
89 ReadExReq,
90 ReadExResp,
91 NUM_MEM_CMDS
92 };
93
94 private:
95 /** List of command attributes. */
96 enum Attribute
97 {
98 IsRead,
99 IsWrite,
100 IsPrefetch,
101 IsInvalidate,
102 IsRequest,
103 IsResponse,
104 NeedsResponse,
105 IsSWPrefetch,
106 IsHWPrefetch,
107 IsUpgrade,
108 HasData,
109 NUM_COMMAND_ATTRIBUTES
110 };
111
112 /** Structure that defines attributes and other data associated
113 * with a Command. */
114 struct CommandInfo {
115 /** Set of attribute flags. */
116 const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
117 /** Corresponding response for requests; InvalidCmd if no
118 * response is applicable. */
119 const Command response;
120 /** String representation (for printing) */
121 const std::string str;
122 };
123
124 /** Array to map Command enum to associated info. */
125 static const CommandInfo commandInfo[];
126
127 private:
128
129 Command cmd;
130
131 bool testCmdAttrib(MemCmd::Attribute attrib) const {
132 return commandInfo[cmd].attributes[attrib] != 0;
133 }
134
135 public:
136
137 bool isRead() const { return testCmdAttrib(IsRead); }
138 bool isWrite() const { return testCmdAttrib(IsWrite); }
139 bool isRequest() const { return testCmdAttrib(IsRequest); }
140 bool isResponse() const { return testCmdAttrib(IsResponse); }
141 bool needsResponse() const { return testCmdAttrib(NeedsResponse); }
142 bool isInvalidate() const { return testCmdAttrib(IsInvalidate); }
143 bool hasData() const { return testCmdAttrib(HasData); }
144
145 const Command responseCommand() const {
146 return commandInfo[cmd].response;
147 }
148
149 /** Return the string to a cmd given by idx. */
150 const std::string &toString() const {
151 return commandInfo[cmd].str;
152 }
153
154 int toInt() const { return (int)cmd; }
155
156 MemCmd(Command _cmd)
157 : cmd(_cmd)
158 { }
159
160 MemCmd(int _cmd)
161 : cmd((Command)_cmd)
162 { }
163
164 MemCmd()
165 : cmd(InvalidCmd)
166 { }
167
168 bool operator==(MemCmd c2) { return (cmd == c2.cmd); }
169 bool operator!=(MemCmd c2) { return (cmd != c2.cmd); }
170
171 friend class Packet;
172};
173
174/**
175 * A Packet is used to encapsulate a transfer between two objects in
176 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
177 * single Request travels all the way from the requester to the
178 * ultimate destination and back, possibly being conveyed by several
179 * different Packets along the way.)
180 */
181class Packet
182{
183 public:
184
185 typedef MemCmd::Command Command;
186
187 /** Temporary FLAGS field until cache gets working, this should be in coherence/sender state. */
188 uint64_t flags;
189
190 private:
191 /** A pointer to the data being transfered. It can be differnt
192 * sizes at each level of the heirarchy so it belongs in the
193 * packet, not request. This may or may not be populated when a
194 * responder recieves the packet. If not populated it memory
195 * should be allocated.
196 */
197 PacketDataPtr data;
198
199 /** Is the data pointer set to a value that shouldn't be freed
200 * when the packet is destroyed? */
201 bool staticData;
202 /** The data pointer points to a value that should be freed when
203 * the packet is destroyed. */
204 bool dynamicData;
205 /** the data pointer points to an array (thus delete [] ) needs to
206 * be called on it rather than simply delete.*/
207 bool arrayData;
208
209 /** The address of the request. This address could be virtual or
210 * physical, depending on the system configuration. */
211 Addr addr;
212
213 /** The size of the request or transfer. */
214 int size;
215
216 /** Device address (e.g., bus ID) of the source of the
217 * transaction. The source is not responsible for setting this
218 * field; it is set implicitly by the interconnect when the
219 * packet is first sent. */
220 short src;
221
222 /** Device address (e.g., bus ID) of the destination of the
223 * transaction. The special value Broadcast indicates that the
224 * packet should be routed based on its address. This field is
225 * initialized in the constructor and is thus always valid
226 * (unlike * addr, size, and src). */
227 short dest;
228
229 /** Are the 'addr' and 'size' fields valid? */
230 bool addrSizeValid;
231 /** Is the 'src' field valid? */
232 bool srcValid;
233
234
235 public:
236
237 /** Used to calculate latencies for each packet.*/
238 Tick time;
239
240 /** The time at which the packet will be fully transmitted */
241 Tick finishTime;
242
243 /** The time at which the first chunk of the packet will be transmitted */
244 Tick firstWordTime;
245
246 /** The special destination address indicating that the packet
247 * should be routed based on its address. */
248 static const short Broadcast = -1;
249
250 /** A pointer to the original request. */
251 RequestPtr req;
252
253 /** A virtual base opaque structure used to hold coherence-related
254 * state. A specific subclass would be derived from this to
255 * carry state specific to a particular coherence protocol. */
256 class CoherenceState {
257 public:
258 virtual ~CoherenceState() {}
259 };
260
261 /** This packet's coherence state. Caches should use
262 * dynamic_cast<> to cast to the state appropriate for the
263 * system's coherence protocol. */
264 CoherenceState *coherence;
265
266 /** A virtual base opaque structure used to hold state associated
267 * with the packet but specific to the sending device (e.g., an
268 * MSHR). A pointer to this state is returned in the packet's
269 * response so that the sender can quickly look up the state
270 * needed to process it. A specific subclass would be derived
271 * from this to carry state specific to a particular sending
272 * device. */
273 class SenderState {
274 public:
275 virtual ~SenderState() {}
276 };
277
278 /** This packet's sender state. Devices should use dynamic_cast<>
279 * to cast to the state appropriate to the sender. */
280 SenderState *senderState;
281
282 public:
283
284 /** The command field of the packet. */
285 MemCmd cmd;
286
287 /** Return the string name of the cmd field (for debugging and
288 * tracing). */
289 const std::string &cmdString() const { return cmd.toString(); }
290
291 /** Return the index of this command. */
292 inline int cmdToIndex() const { return cmd.toInt(); }
293
294 public:
295
296 bool isRead() const { return cmd.isRead(); }
297 bool isWrite() const { return cmd.isWrite(); }
298 bool isRequest() const { return cmd.isRequest(); }
299 bool isResponse() const { return cmd.isResponse(); }
300 bool needsResponse() const { return cmd.needsResponse(); }
301 bool isInvalidate() const { return cmd.isInvalidate(); }
302 bool hasData() const { return cmd.hasData(); }
303
304 bool isCacheFill() const { return (flags & CACHE_LINE_FILL) != 0; }
305 bool isNoAllocate() const { return (flags & NO_ALLOCATE) != 0; }
306 bool isCompressed() const { return (flags & COMPRESSED) != 0; }
307
308 bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN }
309
310 /** Possible results of a packet's request. */
311 enum Result
312 {
313 Success,
314 BadAddress,
315 Nacked,
316 Unknown
317 };
318
319 /** The result of this packet's request. */
320 Result result;
321
322 /** Accessor function that returns the source index of the packet. */
323 short getSrc() const { assert(srcValid); return src; }
324 void setSrc(short _src) { src = _src; srcValid = true; }
325
326 /** Accessor function that returns the destination index of
327 the packet. */
328 short getDest() const { return dest; }
329 void setDest(short _dest) { dest = _dest; }
330
331 Addr getAddr() const { assert(addrSizeValid); return addr; }
332 int getSize() const { assert(addrSizeValid); return size; }
333 Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
334
335 void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
336 void cmdOverride(MemCmd newCmd) { cmd = newCmd; }
337
338 /** Constructor. Note that a Request object must be constructed
339 * first, but the Requests's physical address and size fields
340 * need not be valid. The command and destination addresses
341 * must be supplied. */
342 Packet(Request *_req, MemCmd _cmd, short _dest)
343 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
344 addr(_req->paddr), size(_req->size), dest(_dest),
345 addrSizeValid(_req->validPaddr),
346 srcValid(false),
347 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
348 result(Unknown)
349 {
350 flags = 0;
351 time = curTick;
352 }
353
354 /** Alternate constructor if you are trying to create a packet with
355 * a request that is for a whole block, not the address from the req.
356 * this allows for overriding the size/addr of the req.*/
357 Packet(Request *_req, MemCmd _cmd, short _dest, int _blkSize)
358 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
359 addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize),
360 dest(_dest),
361 addrSizeValid(_req->validPaddr), srcValid(false),
362 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
363 result(Unknown)
364 {
365 flags = 0;
366 time = curTick;
367 }
368
369 /** Destructor. */
370 ~Packet()
371 { if (staticData || dynamicData) deleteData(); }
372
373 /** Reinitialize packet address and size from the associated
374 * Request object, and reset other fields that may have been
375 * modified by a previous transaction. Typically called when a
376 * statically allocated Request/Packet pair is reused for
377 * multiple transactions. */
378 void reinitFromRequest() {
379 assert(req->validPaddr);
380 flags = 0;
381 addr = req->paddr;
382 size = req->size;
383 time = req->time;
384 addrSizeValid = true;
385 result = Unknown;
386 if (dynamicData) {
387 deleteData();
388 dynamicData = false;
389 arrayData = false;
390 }
391 }
392
393 /** Take a request packet and modify it in place to be suitable
394 * for returning as a response to that request. Used for timing
395 * accesses only. For atomic and functional accesses, the
396 * request packet is always implicitly passed back *without*
397 * modifying the destination fields, so this function
398 * should not be called. */
399 void makeTimingResponse() {
400 assert(needsResponse());
401 assert(isRequest());
402 cmd = cmd.responseCommand();
403 dest = src;
404 srcValid = false;
405 }
406
407 /**
408 * Take a request packet and modify it in place to be suitable for
409 * returning as a response to that request.
410 */
411 void makeAtomicResponse()
412 {
413 assert(needsResponse());
414 assert(isRequest());
415 cmd = cmd.responseCommand();
416 }
417
418 /**
419 * Take a request packet that has been returned as NACKED and
420 * modify it so that it can be sent out again. Only packets that
421 * need a response can be NACKED, so verify that that is true.
422 */
423 void
424 reinitNacked()
425 {
426 assert(needsResponse() && result == Nacked);
427 dest = Broadcast;
428 result = Unknown;
429 }
430
431
432 /**
433 * Set the data pointer to the following value that should not be
434 * freed.
435 */
436 template <typename T>
437 void
438 dataStatic(T *p)
439 {
440 if(dynamicData)
441 dynamicData = false;
442 data = (PacketDataPtr)p;
443 staticData = true;
444 }
445
446 /**
447 * Set the data pointer to a value that should have delete []
448 * called on it.
449 */
450 template <typename T>
451 void
452 dataDynamicArray(T *p)
453 {
454 assert(!staticData && !dynamicData);
455 data = (PacketDataPtr)p;
456 dynamicData = true;
457 arrayData = true;
458 }
459
460 /**
461 * set the data pointer to a value that should have delete called
462 * on it.
463 */
464 template <typename T>
465 void
466 dataDynamic(T *p)
467 {
468 assert(!staticData && !dynamicData);
469 data = (PacketDataPtr)p;
470 dynamicData = true;
471 arrayData = false;
472 }
473
474 /** get a pointer to the data ptr. */
475 template <typename T>
476 T*
477 getPtr()
478 {
479 assert(staticData || dynamicData);
480 return (T*)data;
481 }
482
483 /** return the value of what is pointed to in the packet. */
484 template <typename T>
485 T get();
486
487 /** set the value in the data pointer to v. */
488 template <typename T>
489 void set(T v);
490
491 /**
492 * delete the data pointed to in the data pointer. Ok to call to
493 * matter how data was allocted.
494 */
495 void deleteData();
496
497 /** If there isn't data in the packet, allocate some. */
498 void allocate();
499
500 /** Do the packet modify the same addresses. */
501 bool intersect(PacketPtr p);
502};
503
504/** This function given a functional packet and a timing packet either satisfies
505 * the timing packet, or updates the timing packet to reflect the updated state
506 * in the timing packet. It returns if the functional packet should continue to
507 * traverse the memory hierarchy or not.
508 */
509bool fixPacket(PacketPtr func, PacketPtr timing);
510
511/** This function is a wrapper for the fixPacket field that toggles the hasData bit
512 * it is used when a response is waiting in the caches, but hasn't been marked as a
513 * response yet (so the fixPacket needs to get the correct value for the hasData)
514 */
515bool fixDelayedResponsePacket(PacketPtr func, PacketPtr timing);
516
517std::ostream & operator<<(std::ostream &o, const Packet &p);
518
519#endif //__MEM_PACKET_HH