/*
 * Copyright (c) 2008 Princeton University
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * 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: Niket Agarwal
 */

#include "base/stl_helpers.hh"
#include "mem/ruby/network/garnet/flexible-pipeline/Router.hh"
#include "mem/ruby/slicc_interface/NetworkMessage.hh"
#include "mem/ruby/network/garnet/flexible-pipeline/InVcState.hh"
#include "mem/ruby/network/garnet/flexible-pipeline/OutVcState.hh"
#include "mem/ruby/network/garnet/flexible-pipeline/VCarbiter.hh"

using namespace std;
using m5::stl_helpers::deletePointers;

Router::Router(int id, GarnetNetwork *network_ptr)
{
        m_id = id;
        m_net_ptr = network_ptr;
        m_virtual_networks = m_net_ptr->getNumberOfVirtualNetworks();
        m_vc_per_vnet = m_net_ptr->getVCsPerClass();
        m_round_robin_inport = 0;
        m_round_robin_start = 0;
        m_num_vcs = m_vc_per_vnet*m_virtual_networks;
        m_vc_arbiter = new VCarbiter(this);
}

Router::~Router()
{
        for (int i = 0; i < m_in_link.size(); i++)
        {
                deletePointers(m_in_vc_state[i]);
        }
        for (int i = 0; i < m_out_link.size(); i++)
        {
                deletePointers(m_out_vc_state[i]);
                deletePointers(m_router_buffers[i]);
        }
        deletePointers(m_out_src_queue);
        delete m_vc_arbiter;

}

void Router::addInPort(NetworkLink *in_link)
{
        int port = m_in_link.size();
        vector<InVcState *> in_vc_vector;
        for(int i = 0; i < m_num_vcs; i++)
        {
                in_vc_vector.push_back(new InVcState(i));
                in_vc_vector[i]->setState(IDLE_, g_eventQueue_ptr->getTime());
        }
        m_in_vc_state.push_back(in_vc_vector);
        m_in_link.push_back(in_link);
        in_link->setLinkConsumer(this);
        in_link->setInPort(port);

        int start = 0;
        m_round_robin_invc.push_back(start);

}

void Router::addOutPort(NetworkLink *out_link, const NetDest& routing_table_entry, int link_weight)
{
        int port = m_out_link.size();
        out_link->setOutPort(port);
        int start = 0;
        m_vc_round_robin.push_back(start);

        m_out_src_queue.push_back(new flitBuffer());

        m_out_link.push_back(out_link);
        m_routing_table.push_back(routing_table_entry);
        out_link->setSourceQueue(m_out_src_queue[port]);
        out_link->setSource(this);

        vector<flitBuffer *> intermediateQueues;
        for(int i = 0; i < m_num_vcs; i++)
        {
                intermediateQueues.push_back(new flitBuffer(m_net_ptr->getBufferSize()));
        }
        m_router_buffers.push_back(intermediateQueues);

        vector<OutVcState *> out_vc_vector;
        for(int i = 0; i < m_num_vcs; i++)
        {
                out_vc_vector.push_back(new OutVcState(i));
                out_vc_vector[i]->setState(IDLE_, g_eventQueue_ptr->getTime());
        }
        m_out_vc_state.push_back(out_vc_vector);
        m_link_weights.push_back(link_weight);
}

bool Router::isBufferNotFull(int vc, int inport)
{
        int outport = m_in_vc_state[inport][vc]->get_outport();
        int outvc = m_in_vc_state[inport][vc]->get_outvc();

        return (!m_router_buffers[outport][outvc]->isFull());
}

// A request for an output vc has been placed by an upstream Router/NI. This has to be updated and arbitration performed
void Router::request_vc(int in_vc, int in_port, NetDest destination, Time request_time)
{
        assert(m_in_vc_state[in_port][in_vc]->isInState(IDLE_, request_time));

        int outport = getRoute(destination);
        m_in_vc_state[in_port][in_vc]->setRoute(outport);
        m_in_vc_state[in_port][in_vc]->setState(VC_AB_, request_time);
        assert(request_time >= g_eventQueue_ptr->getTime());
        if(request_time > g_eventQueue_ptr->getTime())
                g_eventQueue_ptr->scheduleEventAbsolute(m_vc_arbiter, request_time);
        else
                vc_arbitrate();
}

void Router::vc_arbitrate()
{
        int inport = m_round_robin_inport;
        m_round_robin_inport++;
        if(m_round_robin_inport == m_in_link.size())
                m_round_robin_inport = 0;

        for(int port_iter = 0; port_iter < m_in_link.size(); port_iter++)
        {
                inport++;
                if(inport >= m_in_link.size())
                        inport = 0;
                int invc = m_round_robin_invc[inport];
                m_round_robin_invc[inport]++;

                if(m_round_robin_invc[inport] >= m_num_vcs)
                        m_round_robin_invc[inport] = 0;
                for(int vc_iter = 0; vc_iter < m_num_vcs; vc_iter++)
                {
                        invc++;
                        if(invc >= m_num_vcs)
                                invc = 0;
                        InVcState *in_vc_state = m_in_vc_state[inport][invc];

                        if(in_vc_state->isInState(VC_AB_, g_eventQueue_ptr->getTime()))
                        {
                                int outport = in_vc_state->get_outport();
                                vector<int> valid_vcs = get_valid_vcs(invc);
                                for(int valid_vc_iter = 0; valid_vc_iter < valid_vcs.size(); valid_vc_iter++)
                                {
                                        if(m_out_vc_state[outport][valid_vcs[valid_vc_iter]]->isInState(IDLE_, g_eventQueue_ptr->getTime()))
                                        {
                                                in_vc_state->grant_vc(valid_vcs[valid_vc_iter], g_eventQueue_ptr->getTime());
                                                m_in_link[inport]->grant_vc_link(invc, g_eventQueue_ptr->getTime());
                                                m_out_vc_state[outport][valid_vcs[valid_vc_iter]]->setState(VC_AB_, g_eventQueue_ptr->getTime());
                                                break;
                                        }
                                }
                        }
                }
        }
}

vector<int> Router::get_valid_vcs(int invc)
{
        vector<int> vc_list;

        for(int vnet = 0; vnet < m_virtual_networks; vnet++)
        {
                if(invc >= (vnet*m_vc_per_vnet) && invc < ((vnet+1)*m_vc_per_vnet))
                {
                        int base = vnet*m_vc_per_vnet;
                        int vc_per_vnet;
                        if(m_net_ptr->isVNetOrdered(vnet))
                                vc_per_vnet = 1;
                        else
                                vc_per_vnet = m_vc_per_vnet;

                        for(int offset = 0; offset < vc_per_vnet; offset++)
                        {
                                vc_list.push_back(base+offset);
                        }
                        break;
                }
        }
        return vc_list;
}

void Router::grant_vc(int out_port, int vc, Time grant_time)
{
        assert(m_out_vc_state[out_port][vc]->isInState(VC_AB_, grant_time));
        m_out_vc_state[out_port][vc]->grant_vc(grant_time);
        g_eventQueue_ptr->scheduleEvent(this, 1);
}

void Router::release_vc(int out_port, int vc, Time release_time)
{
        assert(m_out_vc_state[out_port][vc]->isInState(ACTIVE_, release_time));
        m_out_vc_state[out_port][vc]->setState(IDLE_, release_time);
        g_eventQueue_ptr->scheduleEvent(this, 1);
}

// This function calculated the output port for a particular destination.
int Router::getRoute(NetDest destination)
{
        int output_link = -1;
        int min_weight = INFINITE_;
        for(int link = 0; link < m_routing_table.size(); link++)
        {
                if (destination.intersectionIsNotEmpty(m_routing_table[link]))
                {
                        if((m_link_weights[link] >= min_weight))
                                continue;
                        output_link = link;
                        min_weight = m_link_weights[link];
                }
        }
        return output_link;
}

void Router::routeCompute(flit *m_flit, int inport)
{
        int invc = m_flit->get_vc();
        int outport = m_in_vc_state[inport][invc]->get_outport();
        int outvc = m_in_vc_state[inport][invc]->get_outvc();

        assert(m_net_ptr->getNumPipeStages() >= 1);
        m_flit->set_time(g_eventQueue_ptr->getTime() + (m_net_ptr->getNumPipeStages() - 1)); // Becasuse 1 cycle will be consumed in scheduling the output link
        m_flit->set_vc(outvc);
        m_router_buffers[outport][outvc]->insert(m_flit);

        if(m_net_ptr->getNumPipeStages() > 1)
                g_eventQueue_ptr->scheduleEvent(this, m_net_ptr->getNumPipeStages() -1 );
        if((m_flit->get_type() == HEAD_) || (m_flit->get_type() == HEAD_TAIL_))
        {
                NetworkMessage *nm =
                    safe_cast<NetworkMessage*>(m_flit->get_msg_ptr().get());
                NetDest destination = nm->getInternalDestination();
                if(m_net_ptr->getNumPipeStages() > 1)
                {
                        m_out_vc_state[outport][outvc]->setState(VC_AB_, g_eventQueue_ptr->getTime() + 1);
                        m_out_link[outport]->request_vc_link(outvc, destination, g_eventQueue_ptr->getTime() + 1);
                }
                else
                {
                        m_out_vc_state[outport][outvc]->setState(VC_AB_, g_eventQueue_ptr->getTime());
                        m_out_link[outport]->request_vc_link(outvc, destination, g_eventQueue_ptr->getTime());
                }
        }
        if((m_flit->get_type() == TAIL_) || (m_flit->get_type() == HEAD_TAIL_))
        {
                m_in_vc_state[inport][invc]->setState(IDLE_, g_eventQueue_ptr->getTime() + 1);
                m_in_link[inport]->release_vc_link(invc, g_eventQueue_ptr->getTime() + 1);
        }
}

void Router::wakeup()
{
        flit *t_flit;

        int incoming_port = m_round_robin_start; // This is for round-robin scheduling of incoming ports
        m_round_robin_start++;
        if (m_round_robin_start >= m_in_link.size()) {
                m_round_robin_start = 0;
        }

        for(int port = 0; port < m_in_link.size(); port++)
        {
                // Round robin scheduling
                incoming_port++;
                if(incoming_port >= m_in_link.size())
                        incoming_port = 0;
                if(m_in_link[incoming_port]->isReady()) // checking the incoming link
                {
                        DEBUG_EXPR(NETWORK_COMP, HighPrio, m_id);
                        DEBUG_EXPR(NETWORK_COMP, HighPrio, g_eventQueue_ptr->getTime());
                        t_flit = m_in_link[incoming_port]->peekLink();
                        routeCompute(t_flit, incoming_port);
                        m_in_link[incoming_port]->consumeLink();
                }
        }
        scheduleOutputLinks();
        checkReschedule(); // This is for flits lying in the router buffers
        vc_arbitrate();
        check_arbiter_reschedule();
}

void Router::scheduleOutputLinks()
{
        for(int port = 0; port < m_out_link.size(); port++)
        {
                int vc_tolookat = m_vc_round_robin[port];
                m_vc_round_robin[port]++;
                if(m_vc_round_robin[port] == m_num_vcs)
                        m_vc_round_robin[port] = 0;

                for(int i = 0; i < m_num_vcs; i++)
                {
                        vc_tolookat++;
                        if(vc_tolookat == m_num_vcs)
                        vc_tolookat = 0;

                        if(m_router_buffers[port][vc_tolookat]->isReady())
                        {
                                if(m_out_vc_state[port][vc_tolookat]->isInState(ACTIVE_, g_eventQueue_ptr->getTime()) && m_out_link[port]->isBufferNotFull_link(vc_tolookat))
                                // models buffer backpressure
                                {
                                        flit *t_flit = m_router_buffers[port][vc_tolookat]->getTopFlit();
                                        t_flit->set_time(g_eventQueue_ptr->getTime() + 1 );
                                        m_out_src_queue[port]->insert(t_flit);
                                        g_eventQueue_ptr->scheduleEvent(m_out_link[port], 1);
                                        break; // done for this port
                                }
                        }
                }
        }
}

void Router::checkReschedule()
{
        for(int port = 0; port < m_out_link.size(); port++)
        {
                for(int vc = 0; vc < m_num_vcs; vc++)
                {
                        if(m_router_buffers[port][vc]->isReadyForNext())
                        {
                                g_eventQueue_ptr->scheduleEvent(this, 1);
                                return;
                        }
                }
        }
}

void Router::check_arbiter_reschedule()
{
        for(int port = 0; port < m_in_link.size(); port++)
        {
                for(int vc = 0; vc < m_num_vcs; vc++)
                {
                        if(m_in_vc_state[port][vc]->isInState(VC_AB_, g_eventQueue_ptr->getTime() + 1))
                        {
                                g_eventQueue_ptr->scheduleEvent(m_vc_arbiter, 1);
                                return;
                        }
                }
        }
}

void Router::printConfig(ostream& out) const
{
        out << "[Router " << m_id << "] :: " << endl;
        out << "[inLink - ";
        for(int i = 0;i < m_in_link.size(); i++)
                out << m_in_link[i]->get_id() << " - ";
        out << "]" << endl;
        out << "[outLink - ";
        for(int i = 0;i < m_out_link.size(); i++)
                out << m_out_link[i]->get_id() << " - ";
        out << "]" << endl;
/*      out << "---------- routing table -------------" << endl;
        for(int i =0; i < m_routing_table.size(); i++)
                out << m_routing_table[i] << endl;
*/
}

void Router::print(ostream& out) const
{
        out << "[Router]";
}