SystemC-Components-Test/examples/simple_system/gpio.cpp

////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2017, MINRES Technologies GmbH
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
//    this list of conditions and the following disclaimer.
//
// 2. 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.
//
// 3. Neither the name of the copyright holder 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 HOLDER 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.
//
// Contributors:
//       eyck@minres.com - initial implementation
//
//
////////////////////////////////////////////////////////////////////////////////

#include "gpio.h"
#include "scc/report.h"
#include "scc/utilities.h"
#include "gen/gpio_regs.h"
#include <limits>

namespace sysc {

using namespace sc_core;

gpio::gpio(sc_module_name nm)
: sc_module(nm)
, tlm_target<>(clk)
, NAMED(clk_i)
, NAMED(rst_i)
, NAMED(pins_o, 32)
, NAMED(pins_i, 32)
, NAMED(iof0_o, 32)
, NAMED(iof1_o, 32)
, NAMED(iof0_i, 32)
, NAMED(iof1_i, 32)
, NAMEDD(regs, gpio_regs)
{
    regs->registerResources(*this);
    SC_METHOD(clock_cb);
    sensitive << clk_i;
    SC_METHOD(reset_cb);
    sensitive << rst_i;
    dont_initialize();
    auto pins_i_cb =[this](unsigned int tag, tlm::scc::tlm_signal_gp<>& gp,
            tlm::tlm_phase& phase, sc_time& delay)->tlm::tlm_sync_enum{
        this->pin_input(tag, gp, delay);
        return tlm::TLM_COMPLETED;
    };
    auto i=0U;
    for(auto& s:pins_i){
        s.register_nb_transport(pins_i_cb, i);
        ++i;
    }
    auto iof0_i_cb =[this](unsigned int tag, tlm::scc::tlm_signal_gp<>& gp,
            tlm::tlm_phase& phase, sc_time& delay)->tlm::tlm_sync_enum{
        last_iof0[tag]=gp.get_value();
        this->iof_input(tag, 0, gp, delay);
        return tlm::TLM_COMPLETED;
    };
    i=0;
    for(auto& s:iof0_i){
        s.register_nb_transport(iof0_i_cb, i);
        ++i;
    }
    auto iof1_i_cb =[this](unsigned int tag, tlm::scc::tlm_signal_gp<>& gp,
            tlm::tlm_phase& phase, sc_time& delay)->tlm::tlm_sync_enum{
        last_iof1[tag]=gp.get_value();
        this->iof_input(tag, 1, gp, delay);
        return tlm::TLM_COMPLETED;
    };
    i=0;
    for(auto& s:iof1_i){
        s.register_nb_transport(iof1_i_cb, i);
        ++i;
    }
    auto update_pins_cb = [this](scc::sc_register<uint32_t> &reg, uint32_t data, sc_time d) -> bool {
        if (!this->regs->in_reset()) {
            auto changed_bits = (reg.get()^data);
            reg.put(data);
            update_pins(changed_bits);
        }
        return true;
    };
    regs->port.set_write_cb(update_pins_cb);
    regs->output_en.set_write_cb(update_pins_cb);
    regs->out_xor.set_write_cb(update_pins_cb);
    regs->iof_en.set_write_cb(update_pins_cb);
    regs->iof_sel.set_write_cb(update_pins_cb);
}

gpio::~gpio() {}

void gpio::reset_cb() {
    if (rst_i.read()){
        regs->reset_start();
    } else {
        regs->reset_stop();
    }
    update_pins(std::numeric_limits<uint32_t>::max());
}

void gpio::clock_cb() {
	this->clk = clk_i.read();
}

tlm::tlm_phase gpio::write_output(tlm::scc::tlm_signal_gp<bool>& gp, size_t i, bool val) {
    sc_time delay{SC_ZERO_TIME};
    tlm::tlm_phase phase{ tlm::BEGIN_REQ };
    gp.set_command(tlm::TLM_WRITE_COMMAND);
    gp.set_response_status(tlm::TLM_OK_RESPONSE);
    gp.set_value(val);
    pins_o.at(i)->nb_transport_fw(gp, phase, delay);
    return phase;
}

void gpio::update_pins(uint32_t changed_bits) {
    sc_inout_rv<32>::data_type out_val;
    tlm::scc::tlm_signal_gp<bool> gp;
    bool val;
    for(size_t i=0, mask = 1; i<32; ++i, mask<<=1){
        if(changed_bits&mask){
            if((regs->r_iof_en&mask!=0) && (iof0_i[i].size()==0 || iof1_i[i].size()==0)){
                if((regs->r_iof_sel&mask)==0 && iof0_i[i].size()>0){
                    val=last_iof0[i]?sc_dt::Log_1:sc_dt::Log_0;
                } else if((regs->r_iof_sel&mask)==1 && iof1_i[i].size()>0)
                    val=last_iof1[i]?sc_dt::Log_1:sc_dt::Log_0;
            } else {
                if((regs->r_output_en&mask) && (regs->r_port&mask))
                    val=true;
                else
                    val=false;
                if(regs->r_out_xor&mask)
                    val=~val;
            }
            tlm::tlm_phase phase = write_output(gp, i, val);
        }
    }
}

void gpio::pin_input(unsigned int tag, tlm::scc::tlm_signal_gp<bool>& gp, sc_time& delay) {
    if(delay>SC_ZERO_TIME){
        wait(delay);
        delay=SC_ZERO_TIME;
    }
    auto mask = 1u<<tag;
    switch(gp.get_value()){
    case true:
        if(regs->r_output_en&mask==0)
            regs->r_value|=mask;
        forward_pin_input(tag, gp);
        break;
    case false:
        if(regs->r_output_en&mask==0) regs->r_value&=~mask;
        forward_pin_input(tag, gp);
        break;
    }
}

void gpio::forward_pin_input(unsigned int tag, tlm::scc::tlm_signal_gp<bool>& gp) {
    const auto mask = 1U<<tag;
    if(regs->iof_en&mask){
        auto& socket = regs->iof_sel&mask?iof1_o[tag]:iof0_o[tag];
        tlm::scc::tlm_signal_gp<> new_gp;
        for(size_t i=0; i<socket.size(); ++i){
            sc_time delay{SC_ZERO_TIME};
            tlm::tlm_phase phase{tlm::BEGIN_REQ};
            new_gp.set_command(tlm::TLM_WRITE_COMMAND);
            new_gp.set_response_status(tlm::TLM_OK_RESPONSE);
            new_gp.set_value(gp.get_value());
            new_gp.update_extensions_from(gp);
            socket->nb_transport_fw(new_gp, phase, delay); // we don't care about phase and sync enum
        }
    }
}

void gpio::iof_input(unsigned int tag, unsigned iof_idx, tlm::scc::tlm_signal_gp<>& gp, sc_time& delay) {
    if(delay>SC_ZERO_TIME){
         wait(delay);
         delay=SC_ZERO_TIME;
    }
    const auto mask = 1U<<tag;
    if(regs->r_iof_en&mask){
        const auto idx = regs->r_iof_sel&mask?1:0;
        if(iof_idx == idx){
            auto& socket = pins_o[tag];
            for(size_t i=0; i<socket.size(); ++i){
                sc_time delay{SC_ZERO_TIME};
                tlm::tlm_phase phase{tlm::BEGIN_REQ};
                tlm::scc::tlm_signal_gp<> new_gp;
                new_gp.set_command(tlm::TLM_WRITE_COMMAND);
                auto val = gp.get_value();
                new_gp.set_value(val);
                new_gp.copy_extensions_from(gp);
                socket->nb_transport_fw(new_gp, phase, delay); // we don't care about phase and sync enum
                gp.update_extensions_from(new_gp);
            }
        }
    }
}

} /* namespace sysc */