* 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 Decleration of a bus object.
+ * @file
+ * Declaration of a bus object.
*/
#ifndef __MEM_BUS_HH__
#define __MEM_BUS_HH__
#include <string>
+#include <set>
#include <list>
-#include <inttypes.h>
+#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
{
- /** a globally unique id for this bus. */
- int busId;
-
- struct DevMap {
- int portId;
- Range<Addr> range;
- };
- std::vector<DevMap> portList;
-
-
- /** Function called by the port when the bus is recieving a Timing
- transaction.*/
- bool recvTiming(Packet *pkt);
-
- /** Function called by the port when the bus is recieving a Atomic
- transaction.*/
- Tick recvAtomic(Packet *pkt);
-
- /** Function called by the port when the bus is recieving a Functional
- transaction.*/
- void recvFunctional(Packet *pkt);
-
- /** 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.
- * @param id Id of the port this packet was received from (to prevent
- * loops)
- * @return pointer to port that the packet should be sent out of.
- */
- Port *findPort(Addr addr, int id);
-
- /** 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, AddrRangeList &snoop, int id);
-
-
- /** Decleration of the buses port type, one will be instantiated for each
+ /** 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;
/** Constructor for the BusPort.*/
BusPort(const std::string &_name, Bus *_bus, int _id)
- : Port(_name), bus(_bus), id(_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(Packet *pkt)
- { pkt->src = id; return bus->recvTiming(pkt); }
+ 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(Packet *pkt)
- { pkt->src = id; return bus->recvAtomic(pkt); }
+ 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(Packet *pkt)
- { pkt->src = id; bus->recvFunctional(pkt); }
+ 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,
- AddrRangeList &snoop)
+ bool &snoop)
{ bus->addressRanges(resp, snoop, id); }
- // Hack to make translating port work without changes
- virtual int deviceBlockSize() { return 32; }
+ // 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.*/
- std::vector<Port*> interfaces;
+ 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;
+
+ /** Has the user specified their own default responder? */
+ bool responderSet;
+
+ 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);
+ virtual Port *getPort(const std::string &if_name, int idx = -1);
+ virtual void deletePortRefs(Port *p);
virtual void init();
+ virtual void startup();
- Bus(const std::string &n, int bus_id)
- : MemObject(n), busId(bus_id) {}
+ unsigned int drain(Event *de);
+
+ Bus(const BusParams *p)
+ : MemObject(p), busId(p->bus_id), clock(p->clock),
+ headerCycles(p->header_cycles), width(p->width), tickNextIdle(0),
+ drainEvent(NULL), busIdle(this), inRetry(false), maxId(0),
+ defaultPort(NULL), funcPort(NULL), funcPortId(-4),
+ responderSet(p->responder_set), defaultBlockSize(p->block_size),
+ cachedBlockSize(0), cachedBlockSizeValid(false)
+ {
+ //width, clock period, and header cycles must be positive
+ if (width <= 0)
+ fatal("Bus width must be positive\n");
+ if (clock <= 0)
+ fatal("Bus clock period must be positive\n");
+ if (headerCycles <= 0)
+ fatal("Number of header cycles must be positive\n");
+ clearBusCache();
+ clearPortCache();
+ }
};
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