gem5/src/mem/bus.hh
Steve Reinhardt 0685ae7a2d bus: clean up default responder code.
Clean up some minor things left over from the default responder
change in rev 9af6fb59752f.  Mostly renaming the 'responder_set'
param to 'use_default_range' to actually reflect what it does...
old name wasn't that descriptive in the first place, but now
it really doesn't make sense at all.

Also got rid of the bogus obsolete assignment to 'bus.responder'
which used to be a parameter but now is interpreted as an
implicit child assignment, and which was giving me problems in
the config restructuring to come.  (A good argument for not
allowing implicit child assignments, IMO, but that's water under
the bridge, I'm afraid.)

Also moved the Bus constructor to the .cc file since that's
where it should have been all along.
2010-08-17 05:06:21 -07:00

380 lines
12 KiB
C++

/*
* Copyright (c) 2002-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Ron Dreslinski
* Ali Saidi
*/
/**
* @file
* Declaration of a bus object.
*/
#ifndef __MEM_BUS_HH__
#define __MEM_BUS_HH__
#include <string>
#include <set>
#include <list>
#include "base/hashmap.hh"
#include "base/range.hh"
#include "base/range_map.hh"
#include "base/types.hh"
#include "mem/mem_object.hh"
#include "mem/packet.hh"
#include "mem/port.hh"
#include "mem/request.hh"
#include "params/Bus.hh"
#include "sim/eventq.hh"
class Bus : public MemObject
{
/** Declaration of the buses port type, one will be instantiated for each
of the interfaces connecting to the bus. */
class BusPort : public Port
{
bool _onRetryList;
/** A pointer to the bus to which this port belongs. */
Bus *bus;
/** A id to keep track of the intercafe ID this port is connected to. */
int id;
public:
/** Constructor for the BusPort.*/
BusPort(const std::string &_name, Bus *_bus, int _id)
: Port(_name, _bus), _onRetryList(false), bus(_bus), id(_id)
{ }
bool onRetryList()
{ return _onRetryList; }
void onRetryList(bool newVal)
{ _onRetryList = newVal; }
int getId() { return id; }
protected:
/** When reciving a timing request from the peer port (at id),
pass it to the bus. */
virtual bool recvTiming(PacketPtr pkt)
{ pkt->setSrc(id); return bus->recvTiming(pkt); }
/** When reciving a Atomic requestfrom the peer port (at id),
pass it to the bus. */
virtual Tick recvAtomic(PacketPtr pkt)
{ pkt->setSrc(id); return bus->recvAtomic(pkt); }
/** When reciving a Functional requestfrom the peer port (at id),
pass it to the bus. */
virtual void recvFunctional(PacketPtr pkt)
{ pkt->setSrc(id); bus->recvFunctional(pkt); }
/** When reciving a status changefrom the peer port (at id),
pass it to the bus. */
virtual void recvStatusChange(Status status)
{ bus->recvStatusChange(status, id); }
/** When reciving a retry from the peer port (at id),
pass it to the bus. */
virtual void recvRetry()
{ bus->recvRetry(id); }
// This should return all the 'owned' addresses that are
// downstream from this bus, yes? That is, the union of all
// the 'owned' address ranges of all the other interfaces on
// this bus...
virtual void getDeviceAddressRanges(AddrRangeList &resp,
bool &snoop)
{ bus->addressRanges(resp, snoop, id); }
// Ask the bus to ask everyone on the bus what their block size is and
// take the max of it. This might need to be changed a bit if we ever
// support multiple block sizes.
virtual unsigned deviceBlockSize() const
{ return bus->findBlockSize(id); }
};
class BusFreeEvent : public Event
{
Bus * bus;
public:
BusFreeEvent(Bus * _bus);
void process();
const char *description() const;
};
/** a globally unique id for this bus. */
int busId;
/** the clock speed for the bus */
int clock;
/** cycles of overhead per transaction */
int headerCycles;
/** the width of the bus in bytes */
int width;
/** the next tick at which the bus will be idle */
Tick tickNextIdle;
Event * drainEvent;
static const int defaultId = -3; //Make it unique from Broadcast
typedef range_map<Addr,int>::iterator PortIter;
range_map<Addr, int> portMap;
AddrRangeList defaultRange;
typedef std::vector<BusPort*>::iterator SnoopIter;
std::vector<BusPort*> snoopPorts;
/** Function called by the port when the bus is recieving a Timing
transaction.*/
bool recvTiming(PacketPtr pkt);
/** Function called by the port when the bus is recieving a Atomic
transaction.*/
Tick recvAtomic(PacketPtr pkt);
/** Function called by the port when the bus is recieving a Functional
transaction.*/
void recvFunctional(PacketPtr pkt);
/** Timing function called by port when it is once again able to process
* requests. */
void recvRetry(int id);
/** Function called by the port when the bus is recieving a status change.*/
void recvStatusChange(Port::Status status, int id);
/** Find which port connected to this bus (if any) should be given a packet
* with this address.
* @param addr Address to find port for.
* @return id of port that the packet should be sent out of.
*/
int findPort(Addr addr);
// Cache for the findPort function storing recently used ports from portMap
struct PortCache {
bool valid;
int id;
Addr start;
Addr end;
};
PortCache portCache[3];
// Checks the cache and returns the id of the port that has the requested
// address within its range
inline int checkPortCache(Addr addr) {
if (portCache[0].valid && addr >= portCache[0].start &&
addr < portCache[0].end) {
return portCache[0].id;
}
if (portCache[1].valid && addr >= portCache[1].start &&
addr < portCache[1].end) {
return portCache[1].id;
}
if (portCache[2].valid && addr >= portCache[2].start &&
addr < portCache[2].end) {
return portCache[2].id;
}
return -1;
}
// Clears the earliest entry of the cache and inserts a new port entry
inline void updatePortCache(short id, Addr start, Addr end) {
portCache[2].valid = portCache[1].valid;
portCache[2].id = portCache[1].id;
portCache[2].start = portCache[1].start;
portCache[2].end = portCache[1].end;
portCache[1].valid = portCache[0].valid;
portCache[1].id = portCache[0].id;
portCache[1].start = portCache[0].start;
portCache[1].end = portCache[0].end;
portCache[0].valid = true;
portCache[0].id = id;
portCache[0].start = start;
portCache[0].end = end;
}
// Clears the cache. Needs to be called in constructor.
inline void clearPortCache() {
portCache[2].valid = false;
portCache[1].valid = false;
portCache[0].valid = false;
}
/** Process address range request.
* @param resp addresses that we can respond to
* @param snoop addresses that we would like to snoop
* @param id ide of the busport that made the request.
*/
void addressRanges(AddrRangeList &resp, bool &snoop, int id);
/** Calculate the timing parameters for the packet. Updates the
* firstWordTime and finishTime fields of the packet object.
* Returns the tick at which the packet header is completed (which
* will be all that is sent if the target rejects the packet).
*/
Tick calcPacketTiming(PacketPtr pkt);
/** Occupy the bus until until */
void occupyBus(Tick until);
/** Ask everyone on the bus what their size is
* @param id id of the busport that made the request
* @return the max of all the sizes
*/
unsigned findBlockSize(int id);
BusFreeEvent busIdle;
bool inRetry;
std::set<int> inRecvStatusChange;
/** max number of bus ids we've handed out so far */
short maxId;
/** An array of pointers to the peer port interfaces
connected to this bus.*/
m5::hash_map<short,BusPort*> interfaces;
/** An array of pointers to ports that retry should be called on because the
* original send failed for whatever reason.*/
std::list<BusPort*> retryList;
void addToRetryList(BusPort * port)
{
if (!inRetry) {
// The device wasn't retrying a packet, or wasn't at an appropriate
// time.
assert(!port->onRetryList());
port->onRetryList(true);
retryList.push_back(port);
} else {
if (port->onRetryList()) {
// The device was retrying a packet. It didn't work, so we'll leave
// it at the head of the retry list.
assert(port == retryList.front());
inRetry = false;
}
else {
port->onRetryList(true);
retryList.push_back(port);
}
}
}
/** Port that handles requests that don't match any of the interfaces.*/
BusPort *defaultPort;
BusPort *funcPort;
int funcPortId;
/** If true, use address range provided by default device. Any
address not handled by another port and not in default device's
range will cause a fatal error. If false, just send all
addresses not handled by another port to default device. */
bool useDefaultRange;
unsigned defaultBlockSize;
unsigned cachedBlockSize;
bool cachedBlockSizeValid;
// Cache for the peer port interfaces
struct BusCache {
bool valid;
short id;
BusPort *port;
};
BusCache busCache[3];
// Checks the peer port interfaces cache for the port id and returns
// a pointer to the matching port
inline BusPort* checkBusCache(short id) {
if (busCache[0].valid && id == busCache[0].id) {
return busCache[0].port;
}
if (busCache[1].valid && id == busCache[1].id) {
return busCache[1].port;
}
if (busCache[2].valid && id == busCache[2].id) {
return busCache[2].port;
}
return NULL;
}
// Replaces the earliest entry in the cache with a new entry
inline void updateBusCache(short id, BusPort *port) {
busCache[2].valid = busCache[1].valid;
busCache[2].id = busCache[1].id;
busCache[2].port = busCache[1].port;
busCache[1].valid = busCache[0].valid;
busCache[1].id = busCache[0].id;
busCache[1].port = busCache[0].port;
busCache[0].valid = true;
busCache[0].id = id;
busCache[0].port = port;
}
// Invalidates the cache. Needs to be called in constructor.
inline void clearBusCache() {
busCache[2].valid = false;
busCache[1].valid = false;
busCache[0].valid = false;
}
public:
/** A function used to return the port associated with this bus object. */
virtual Port *getPort(const std::string &if_name, int idx = -1);
virtual void deletePortRefs(Port *p);
virtual void init();
virtual void startup();
unsigned int drain(Event *de);
Bus(const BusParams *p);
};
#endif //__MEM_BUS_HH__