diff options
Diffstat (limited to 'src/mem/bridge.hh')
| -rw-r--r-- | src/mem/bridge.hh | 138 |
1 files changed, 49 insertions, 89 deletions
diff --git a/src/mem/bridge.hh b/src/mem/bridge.hh index cc428e44d..cf7673c47 100644 --- a/src/mem/bridge.hh +++ b/src/mem/bridge.hh @@ -52,15 +52,10 @@ #define __MEM_BRIDGE_HH__ #include <list> -#include <queue> -#include <string> #include "base/types.hh" #include "mem/mem_object.hh" -#include "mem/packet.hh" -#include "mem/port.hh" #include "params/Bridge.hh" -#include "sim/eventq.hh" /** * A bridge is used to interface two different busses (or in general a @@ -71,9 +66,9 @@ * The bridge comprises a slave port and a master port, that buffer * outgoing responses and requests respectively. Buffer space is * reserved when a request arrives, also reserving response space - * before forwarding the request. An incoming request is always - * accepted (recvTiming returns true), but is potentially NACKed if - * there is no request space or response space. + * before forwarding the request. If there is no space present, then + * the bridge will delay accepting the packet until space becomes + * available. */ class Bridge : public MemObject { @@ -106,40 +101,18 @@ class Bridge : public MemObject }; /** - * A deferred request stores a packet along with its scheduled - * transmission time, and whether we can expect to see a response - * or not. + * A deferred packet stores a packet along with its scheduled + * transmission time */ - class DeferredRequest + class DeferredPacket { public: - Tick ready; + Tick tick; PacketPtr pkt; - bool expectResponse; - DeferredRequest(PacketPtr _pkt, Tick t) - : ready(t), pkt(_pkt), expectResponse(_pkt->needsResponse()) - { } - }; - - /** - * A deferred response stores a packet along with its scheduled - * transmission time. It also contains information of whether the - * bridge NACKed the packet to be able to correctly maintain - * counters of outstanding responses. - */ - class DeferredResponse { - - public: - - Tick ready; - PacketPtr pkt; - bool nackedHere; - - DeferredResponse(PacketPtr _pkt, Tick t, bool nack = false) - : ready(t), pkt(_pkt), nackedHere(nack) + DeferredPacket(PacketPtr _pkt, Tick _tick) : tick(_tick), pkt(_pkt) { } }; @@ -157,21 +130,18 @@ class Bridge : public MemObject private: - /** A pointer to the bridge to which this port belongs. */ - Bridge *bridge; + /** The bridge to which this port belongs. */ + Bridge& bridge; /** - * Master port on the other side of the bridge - * (connected to the other bus). + * Master port on the other side of the bridge (connected to + * the other bus). */ BridgeMasterPort& masterPort; /** Minimum request delay though this bridge. */ Tick delay; - /** Min delay to respond with a nack. */ - Tick nackDelay; - /** Address ranges to pass through the bridge */ AddrRangeList ranges; @@ -180,13 +150,13 @@ class Bridge : public MemObject * queue for a specified delay to model the processing delay * of the bridge. */ - std::list<DeferredResponse> responseQueue; + std::list<DeferredPacket> transmitList; /** Counter to track the outstanding responses. */ unsigned int outstandingResponses; - /** If we're waiting for a retry to happen. */ - bool inRetry; + /** If we should send a retry when space becomes available. */ + bool retryReq; /** Max queue size for reserved responses. */ unsigned int respQueueLimit; @@ -199,22 +169,15 @@ class Bridge : public MemObject bool respQueueFull(); /** - * Turn the request packet into a NACK response and put it in - * the response queue and schedule its transmission. - * - * @param pkt the request packet to NACK - */ - void nackRequest(PacketPtr pkt); - - /** * Handle send event, scheduled when the packet at the head of * the response queue is ready to transmit (for timing * accesses only). */ - void trySend(); + void trySendTiming(); /** Send event for the response queue. */ - EventWrapper<BridgeSlavePort, &BridgeSlavePort::trySend> sendEvent; + EventWrapper<BridgeSlavePort, + &BridgeSlavePort::trySendTiming> sendEvent; public: @@ -225,44 +188,50 @@ class Bridge : public MemObject * @param _bridge the structural owner * @param _masterPort the master port on the other side of the bridge * @param _delay the delay from seeing a response to sending it - * @param _nack_delay the delay from a NACK to sending the response * @param _resp_limit the size of the response queue * @param _ranges a number of address ranges to forward */ - BridgeSlavePort(const std::string &_name, Bridge *_bridge, + BridgeSlavePort(const std::string& _name, Bridge& _bridge, BridgeMasterPort& _masterPort, int _delay, - int _nack_delay, int _resp_limit, - std::vector<Range<Addr> > _ranges); + int _resp_limit, std::vector<Range<Addr> > _ranges); /** * Queue a response packet to be sent out later and also schedule * a send if necessary. * * @param pkt a response to send out after a delay + * @param when tick when response packet should be sent + */ + void schedTimingResp(PacketPtr pkt, Tick when); + + /** + * Retry any stalled request that we have failed to accept at + * an earlier point in time. This call will do nothing if no + * request is waiting. */ - void queueForSendTiming(PacketPtr pkt); + void retryStalledReq(); protected: /** When receiving a timing request from the peer port, pass it to the bridge. */ - virtual bool recvTimingReq(PacketPtr pkt); + bool recvTimingReq(PacketPtr pkt); /** When receiving a retry request from the peer port, pass it to the bridge. */ - virtual void recvRetry(); + void recvRetry(); /** When receiving a Atomic requestfrom the peer port, pass it to the bridge. */ - virtual Tick recvAtomic(PacketPtr pkt); + Tick recvAtomic(PacketPtr pkt); /** When receiving a Functional request from the peer port, pass it to the bridge. */ - virtual void recvFunctional(PacketPtr pkt); + void recvFunctional(PacketPtr pkt); /** When receiving a address range request the peer port, pass it to the bridge. */ - virtual AddrRangeList getAddrRanges() const; + AddrRangeList getAddrRanges() const; }; @@ -276,12 +245,12 @@ class Bridge : public MemObject private: - /** A pointer to the bridge to which this port belongs. */ - Bridge* bridge; + /** The bridge to which this port belongs. */ + Bridge& bridge; /** - * Pointer to the slave port on the other side of the bridge - * (connected to the other bus). + * The slave port on the other side of the bridge (connected + * to the other bus). */ BridgeSlavePort& slavePort; @@ -293,10 +262,7 @@ class Bridge : public MemObject * queue for a specified delay to model the processing delay * of the bridge. */ - std::list<DeferredRequest> requestQueue; - - /** If we're waiting for a retry to happen. */ - bool inRetry; + std::list<DeferredPacket> transmitList; /** Max queue size for request packets */ unsigned int reqQueueLimit; @@ -306,10 +272,11 @@ class Bridge : public MemObject * the outbound queue is ready to transmit (for timing * accesses only). */ - void trySend(); + void trySendTiming(); /** Send event for the request queue. */ - EventWrapper<BridgeMasterPort, &BridgeMasterPort::trySend> sendEvent; + EventWrapper<BridgeMasterPort, + &BridgeMasterPort::trySendTiming> sendEvent; public: @@ -322,7 +289,7 @@ class Bridge : public MemObject * @param _delay the delay from seeing a request to sending it * @param _req_limit the size of the request queue */ - BridgeMasterPort(const std::string &_name, Bridge *_bridge, + BridgeMasterPort(const std::string& _name, Bridge& _bridge, BridgeSlavePort& _slavePort, int _delay, int _req_limit); @@ -338,8 +305,9 @@ class Bridge : public MemObject * a send if necessary. * * @param pkt a request to send out after a delay + * @param when tick when response packet should be sent */ - void queueForSendTiming(PacketPtr pkt); + void schedTimingReq(PacketPtr pkt, Tick when); /** * Check a functional request against the packets in our @@ -355,11 +323,11 @@ class Bridge : public MemObject /** When receiving a timing request from the peer port, pass it to the bridge. */ - virtual bool recvTimingResp(PacketPtr pkt); + bool recvTimingResp(PacketPtr pkt); /** When receiving a retry request from the peer port, pass it to the bridge. */ - virtual void recvRetry(); + void recvRetry(); }; /** Slave port of the bridge. */ @@ -368,17 +336,7 @@ class Bridge : public MemObject /** Master port of the bridge. */ BridgeMasterPort masterPort; - /** If this bridge should acknowledge writes. */ - bool ackWrites; - public: - typedef BridgeParams Params; - - protected: - Params *_params; - - public: - const Params *params() const { return _params; } virtual MasterPort& getMasterPort(const std::string& if_name, int idx = -1); @@ -386,6 +344,8 @@ class Bridge : public MemObject virtual void init(); + typedef BridgeParams Params; + Bridge(Params *p); }; |