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# Authors: Thomas Grass
#          Andreas Hansson
#          Sascha Bischoff

from m5.params import *
from m5.proxy import *
from m5.objects.ClockedObject import ClockedObject

# Types of Stream Generators.
# Those are orthogonal to the other generators in the TrafficGen
# and are meant to initialize the stream and substream IDs for
# every memory request, regardless of how the packet has been
# generated (Random, Linear, Trace etc)
class StreamGenType(Enum): vals = [ 'none', 'fixed', 'random' ]

# The traffic generator is a master module that generates stimuli for
# the memory system, based on a collection of simple behaviours that
# are either probabilistic or based on traces. It can be used stand
# alone for creating test cases for interconnect and memory
# controllers, or function as a black-box replacement for system
# components that are not yet modelled in detail, e.g. a video engine
# or baseband subsystem in an SoC.
class BaseTrafficGen(ClockedObject):
    type = 'BaseTrafficGen'
    abstract = True
    cxx_header = "cpu/testers/traffic_gen/traffic_gen.hh"

    # Port used for sending requests and receiving responses
    port = MasterPort("Master port")

    # System used to determine the mode of the memory system
    system = Param.System(Parent.any, "System this generator is part of")

    # Should requests respond to back-pressure or not, if true, the
    # rate of the traffic generator will be slowed down if requests
    # are not immediately accepted
    elastic_req = Param.Bool(False,
                             "Slow down requests in case of backpressure")

    # Maximum number of requests waiting for response. Set to 0 for an
    # unlimited number of outstanding requests.
    max_outstanding_reqs = Param.Int(0,
                            "Maximum number of outstanding requests")

    # Let the user know if we have waited for a retry and not made any
    # progress for a long period of time. The default value is
    # somewhat arbitrary and may well have to be tuned.
    progress_check = Param.Latency('1ms', "Time before exiting " \
                                   "due to lack of progress")

    # Generator type used for applying Stream and/or Substream IDs to requests
    stream_gen = Param.StreamGenType('none',
        "Generator for adding Stream and/or Substream ID's to requests")

    # Sources for Stream/Substream IDs to apply to requests
    sids = VectorParam.Unsigned([], "StreamIDs to use")
    ssids = VectorParam.Unsigned([], "SubstreamIDs to use")

    # These additional parameters allow TrafficGen to be used with scripts
    # that expect a BaseCPU
    cpu_id = Param.Int(-1, "CPU identifier")
    socket_id = Param.Unsigned(0, "Physical Socket identifier")
    numThreads = Param.Unsigned(1, "number of HW thread contexts")

    @classmethod
    def memory_mode(cls):
        return 'timing'

    @classmethod
    def require_caches(cls):
        return False

    def createThreads(self):
        pass

    def createInterruptController(self):
        pass

    def connectCachedPorts(self, bus):
        if hasattr(self, '_cached_ports') and (len(self._cached_ports) > 0):
            for p in self._cached_ports:
                exec('self.%s = bus.slave' % p)
        else:
            self.port = bus.slave

    def connectAllPorts(self, cached_bus, uncached_bus = None):
        self.connectCachedPorts(cached_bus)

    def addPrivateSplitL1Caches(self, ic, dc, iwc = None, dwc = None):
        self.dcache = dc
        self.port = dc.cpu_side
        self._cached_ports = ['dcache.mem_side']
        self._uncached_ports = []