# Copyright (c) 2010 Advanced Micro Devices, Inc.
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# Authors: Brad Beckmann

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

class MeshDirCorners(Topology):
    description='MeshDirCorners'

# This file contains a special network creation function.  This
# networks is not general and will only work with specific system
# configurations.  The network specified is similar to GEMS old file
# specified network.

def makeTopology(nodes, options):
    num_routers = options.num_cpus
    num_rows = options.mesh_rows

    # First determine which nodes are cache cntrls vs. dirs vs. dma
    cache_nodes = []
    dir_nodes = []
    dma_nodes = []
    for node in nodes:
        if node.type == 'L1Cache_Controller' or \
           node.type == 'L2Cache_Controller':
            cache_nodes.append(node)
        elif node.type == 'Directory_Controller':
            dir_nodes.append(node)
        elif node.type == 'DMA_Controller':
            dma_nodes.append(node)

    # Obviously the number or rows must be <= the number of routers
    # and evenly divisible.  Also the number of caches must be a
    # multiple of the number of routers and the number of directories
    # must be four.
    assert(num_rows <= num_routers)
    num_columns = int(num_routers / num_rows)
    assert(num_columns * num_rows == num_routers)
    caches_per_router, remainder = divmod(len(cache_nodes), num_routers)
    assert(remainder == 0)
    assert(len(dir_nodes) == 4)

    # Connect each cache controller to the appropriate router
    ext_links = []
    for (i, n) in enumerate(cache_nodes):
        cntrl_level, router_id = divmod(i, num_routers)
        assert(cntrl_level < caches_per_router)
        ext_links.append(ExtLink(ext_node=n, int_node=router_id))

    # Connect the dir nodes to the corners.
    ext_links.append(ExtLink(ext_node=dir_nodes[0], int_node=0))
    ext_links.append(ExtLink(ext_node=dir_nodes[1],
                             int_node=(num_columns - 1)))

    ext_links.append(ExtLink(ext_node=dir_nodes[2],
                             int_node=(num_routers - num_columns)))

    ext_links.append(ExtLink(ext_node=dir_nodes[3],
                             int_node=(num_routers - 1)))

    # Connect the dma nodes to router 0.  These should only be DMA nodes.
    for (i, node) in enumerate(dma_nodes):
        assert(node.type == 'DMA_Controller')
        ext_links.append(ExtLink(ext_node=node, int_node=0))

    # Create the mesh links.  First row (east-west) links then column
    # (north-south) links
    int_links = []
    for row in xrange(num_rows):
        for col in xrange(num_columns):
            if (col + 1 < num_columns):
                east_id = col + (row * num_columns)
                west_id = (col + 1) + (row * num_columns)
                int_links.append(IntLink(node_a=east_id,
                                         node_b=west_id,
                                         weight=1))
    for col in xrange(num_columns):
        for row in xrange(num_rows):
            if (row + 1 < num_rows):
                north_id = col + (row * num_columns)
                south_id = col + ((row + 1) * num_columns)
                int_links.append(IntLink(node_a=north_id,
                                         node_b=south_id,
                                         weight=2))

    return MeshDirCorners(ext_links=ext_links,
                          int_links=int_links,
                          num_int_nodes=num_routers)