port.hh revision 4022 
1/*
2 * Copyright (c) 2002-2005 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 */
30
31/**
32 * @file
33 * Port Object Declaration. Ports are used to interface memory objects to
34 * each other.  They will always come in pairs, and we refer to the other
35 * port object as the peer.  These are used to make the design more
36 * modular so that a specific interface between every type of objcet doesn't
37 * have to be created.
38 */
39
40#ifndef __MEM_PORT_HH__
41#define __MEM_PORT_HH__
42
43#include <list>
44#include <inttypes.h>
45
46#include "base/misc.hh"
47#include "base/range.hh"
48#include "mem/packet.hh"
49#include "mem/request.hh"
50
51/** This typedef is used to clean up the parameter list of
52 * getDeviceAddressRanges() and getPeerAddressRanges().  It's declared
53 * outside the Port object since it's also used by some mem objects.
54 * Eventually we should move this typedef to wherever Addr is
55 * defined.
56 */
57
58typedef std::list<Range<Addr> > AddrRangeList;
59typedef std::list<Range<Addr> >::iterator AddrRangeIter;
60
61class MemObject;
62
63/**
64 * Ports are used to interface memory objects to
65 * each other.  They will always come in pairs, and we refer to the other
66 * port object as the peer.  These are used to make the design more
67 * modular so that a specific interface between every type of objcet doesn't
68 * have to be created.
69 *
70 * Recv accesor functions are being called from the peer interface.
71 * Send accessor functions are being called from the device the port is
72 * associated with, and it will call the peer recv. accessor function.
73 */
74class Port
75{
76  private:
77
78    /** Descriptive name (for DPRINTF output) */
79    mutable std::string portName;
80
81    /** A pointer to the peer port.  Ports always come in pairs, that way they
82        can use a standardized interface to communicate between different
83        memory objects. */
84    Port *peer;
85
86    /** A pointer to the MemObject that owns this port. This may not be set. */
87    MemObject *owner;
88
89  public:
90
91    Port()
92        : peer(NULL), owner(NULL)
93    { }
94
95    /**
96     * Constructor.
97     *
98     * @param _name Port name for DPRINTF output.  Should include name
99     * of memory system object to which the port belongs.
100     * @param _owner Pointer to the MemObject that owns this port.
101     * Will not necessarily be set.
102     */
103    Port(const std::string &_name, MemObject *_owner = NULL)
104        : portName(_name), peer(NULL), owner(_owner)
105    { }
106
107    /** Return port name (for DPRINTF). */
108    const std::string &name() const { return portName; }
109
110    virtual ~Port() {};
111
112    // mey be better to use subclasses & RTTI?
113    /** Holds the ports status.  Currently just that a range recomputation needs
114     * to be done. */
115    enum Status {
116        RangeChange
117    };
118
119    void setName(const std::string &name)
120    { portName = name; }
121
122    /** Function to set the pointer for the peer port. */
123    void setPeer(Port *port);
124
125    /** Function to get the pointer to the peer port. */
126    Port *getPeer() { return peer; }
127
128    /** Function to set the owner of this port. */
129    void setOwner(MemObject *_owner) { owner = _owner; }
130
131    /** Function to return the owner of this port. */
132    MemObject *getOwner() { return owner; }
133
134  protected:
135
136    /** These functions are protected because they should only be
137     * called by a peer port, never directly by any outside object. */
138
139    /** Called to recive a timing call from the peer port. */
140    virtual bool recvTiming(PacketPtr pkt) = 0;
141
142    /** Called to recive a atomic call from the peer port. */
143    virtual Tick recvAtomic(PacketPtr pkt) = 0;
144
145    /** Called to recive a functional call from the peer port. */
146    virtual void recvFunctional(PacketPtr pkt) = 0;
147
148    /** Called to recieve a status change from the peer port. */
149    virtual void recvStatusChange(Status status) = 0;
150
151    /** Called by a peer port if the send was unsuccesful, and had to
152        wait.  This shouldn't be valid for response paths (IO Devices).
153        so it is set to panic if it isn't already defined.
154    */
155    virtual void recvRetry() { panic("??"); }
156
157    /** Called by a peer port in order to determine the block size of the
158        device connected to this port.  It sometimes doesn't make sense for
159        this function to be called, a DMA interface doesn't really have a
160        block size, so it is defaulted to a panic.
161    */
162    virtual int deviceBlockSize() { panic("??"); M5_DUMMY_RETURN }
163
164    /** The peer port is requesting us to reply with a list of the ranges we
165        are responsible for.
166        @param resp is a list of ranges responded to
167        @param snoop is a list of ranges snooped
168    */
169    virtual void getDeviceAddressRanges(AddrRangeList &resp,
170            AddrRangeList &snoop)
171    { panic("??"); }
172
173  public:
174
175    /** Function called by associated memory device (cache, memory, iodevice)
176        in order to send a timing request to the port.  Simply calls the peer
177        port receive function.
178        @return This function returns if the send was succesful in it's
179        recieve. If it was a failure, then the port will wait for a recvRetry
180        at which point it can possibly issue a successful sendTiming.  This is used in
181        case a cache has a higher priority request come in while waiting for
182        the bus to arbitrate.
183    */
184    bool sendTiming(PacketPtr pkt) { return peer->recvTiming(pkt); }
185
186    /** Function called by the associated device to send an atomic
187     *   access, an access in which the data is moved and the state is
188     *   updated in one cycle, without interleaving with other memory
189     *   accesses.  Returns estimated latency of access.
190     */
191    Tick sendAtomic(PacketPtr pkt)
192        { return peer->recvAtomic(pkt); }
193
194    /** Function called by the associated device to send a functional access,
195        an access in which the data is instantly updated everywhere in the
196        memory system, without affecting the current state of any block or
197        moving the block.
198    */
199    void sendFunctional(PacketPtr pkt)
200        { return peer->recvFunctional(pkt); }
201
202    /** Called by the associated device to send a status change to the device
203        connected to the peer interface.
204    */
205    void sendStatusChange(Status status) {peer->recvStatusChange(status); }
206
207    /** When a timing access doesn't return a success, some time later the
208        Retry will be sent.
209    */
210    void sendRetry() { return peer->recvRetry(); }
211
212    /** Called by the associated device if it wishes to find out the blocksize
213        of the device on attached to the peer port.
214    */
215    int peerBlockSize() { return peer->deviceBlockSize(); }
216
217    /** Called by the associated device if it wishes to find out the address
218        ranges connected to the peer ports devices.
219    */
220    void getPeerAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
221    { peer->getDeviceAddressRanges(resp, snoop); }
222
223    /** This function is a wrapper around sendFunctional()
224        that breaks a larger, arbitrarily aligned access into
225        appropriate chunks.  The default implementation can use
226        getBlockSize() to determine the block size and go from there.
227    */
228    virtual void readBlob(Addr addr, uint8_t *p, int size);
229
230    /** This function is a wrapper around sendFunctional()
231        that breaks a larger, arbitrarily aligned access into
232        appropriate chunks.  The default implementation can use
233        getBlockSize() to determine the block size and go from there.
234    */
235    virtual void writeBlob(Addr addr, uint8_t *p, int size);
236
237    /** Fill size bytes starting at addr with byte value val.  This
238        should not need to be virtual, since it can be implemented in
239        terms of writeBlob().  However, it shouldn't be
240        performance-critical either, so it could be if we wanted to.
241    */
242    virtual void memsetBlob(Addr addr, uint8_t val, int size);
243
244  private:
245
246    /** Internal helper function for read/writeBlob().
247     */
248    void blobHelper(Addr addr, uint8_t *p, int size, MemCmd cmd);
249};
250
251/** A simple functional port that is only meant for one way communication to
252 * physical memory. It is only meant to be used to load data into memory before
253 * the simulation begins.
254 */
255
256class FunctionalPort : public Port
257{
258  public:
259    FunctionalPort(const std::string &_name, MemObject *_owner = NULL)
260        : Port(_name, _owner)
261    {}
262
263  protected:
264    virtual bool recvTiming(PacketPtr pkt) { panic("FuncPort is UniDir");
265        M5_DUMMY_RETURN }
266    virtual Tick recvAtomic(PacketPtr pkt) { panic("FuncPort is UniDir");
267        M5_DUMMY_RETURN }
268    virtual void recvFunctional(PacketPtr pkt) { panic("FuncPort is UniDir"); }
269    virtual void recvStatusChange(Status status) {}
270
271  public:
272    /** a write function that also does an endian conversion. */
273    template <typename T>
274    inline void writeHtoG(Addr addr, T d);
275
276    /** a read function that also does an endian conversion. */
277    template <typename T>
278    inline T readGtoH(Addr addr);
279
280    template <typename T>
281    inline void write(Addr addr, T d)
282    {
283        writeBlob(addr, (uint8_t*)&d, sizeof(T));
284    }
285
286    template <typename T>
287    inline T read(Addr addr)
288    {
289        T d;
290        readBlob(addr, (uint8_t*)&d, sizeof(T));
291        return d;
292    }
293};
294
295#endif //__MEM_PORT_HH__
296