# Copyright (c) 2010 Advanced Micro Devices, Inc.
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# Authors: Steve Reinhardt

from m5.params import *
from m5.objects import *

from BaseTopology import SimpleTopology

class Crossbar(SimpleTopology):
    description='Crossbar'

    def makeTopology(self, options, network, IntLink, ExtLink, Router):

        # default values for link latency and router latency.
        # Can be over-ridden on a per link/router basis
        link_latency = options.link_latency # used by simple and garnet
        router_latency = options.router_latency # only used by garnet

        # Create an individual router for each controller plus one more for
        # the centralized crossbar.  The large numbers of routers are needed
        # because external links do not model outgoing bandwidth in the
        # simple network, but internal links do.
        # For garnet, one router suffices, use CrossbarGarnet.py

        routers = [Router(router_id=i) for i in range(len(self.nodes)+1)]
        xbar = routers[len(self.nodes)] # the crossbar router is the last router created
        network.routers = routers

        ext_links = [ExtLink(link_id=i, ext_node=n, int_node=routers[i],
                             latency = link_latency)
                        for (i, n) in enumerate(self.nodes)]
        network.ext_links = ext_links

        link_count = len(self.nodes)

        int_links = []
        for i in range(len(self.nodes)):
            int_links.append(IntLink(link_id=(link_count+i),
                                     src_node=routers[i],
                                     dst_node=xbar,
                                     latency = link_latency))

        link_count += len(self.nodes)

        for i in range(len(self.nodes)):
            int_links.append(IntLink(link_id=(link_count+i),
                                     src_node=xbar,
                                     dst_node=routers[i],
                                     latency = link_latency))

        network.int_links = int_links