mayhem-firmware/firmware/application/rf_path.cpp

/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "rf_path.hpp"
#include "platform.hpp"

#include <array>
#include <initializer_list>

#include "hackrf_gpio.hpp"
using namespace hackrf::one;

#include "utility.hpp"

namespace rf {
namespace path {

namespace {

#ifdef PRALINE
/* PRALINE uses a simplified RF path with only 5 control signals.
 * The RF path architecture is completely different from HackRF One.
 */
struct PralineConfig {
    bool tx_en;
    bool mix_bypass;  // RF path mixer bypass (GPIO3[2])
    bool lpf_en;
    bool rf_amp_en;
    bool ant_bias_en_n;  // Inverted: 0 = bias enabled

    static void gpio_init() {
        gpio_tx_enable.output();
        gpio_mix_bypass.output();
        gpio_lpf_enable.output();
        gpio_rf_amp_enable.output();
        gpio_ant_bias_disable.output();
    }

    void apply() const {
        gpio_tx_enable.write(tx_en);
        gpio_mix_bypass.write(mix_bypass);  // Control RF path mixer
        gpio_lpf_enable.write(lpf_en);
        gpio_rf_amp_enable.write(rf_amp_en);
        gpio_ant_bias_disable.write(ant_bias_en_n);
    }
};

#else
/* HackRF One uses 11 GPIOs for RF path control */
using GPIOs = std::array<GPIO, 11>;

/* TODO: ARM GCC 4.8 2014q3 doesn't like this array inside struct Config.
 * No idea why.
 */
constexpr GPIOs gpios{
    gpio_mix_bypass,
    gpio_not_mix_bypass,
    gpio_tx_mix_bp,
    gpio_rx_mix_bp,
    gpio_hp,
    gpio_lp,
    gpio_amp_bypass,
    gpio_tx_amp,
    gpio_not_tx_amp_pwr,
    gpio_rx_amp,
    gpio_not_rx_amp_pwr,
};

/* HackRF One Config struct - not used on PRALINE */
struct Config {
    using base_type = uint16_t;

    union {
        struct {
            bool tx : 1;
            bool rx : 1;
            bool mix_bypass : 1;
            bool not_mix_bypass : 1;
            bool tx_mix_bp : 1;
            bool rx_mix_bp : 1;
            bool hp : 1;
            bool lp : 1;
            bool amp_bypass : 1;
            bool tx_amp : 1;
            bool not_tx_amp : 1;
            bool rx_amp : 1;
            bool not_rx_amp : 1;
        };
        base_type w;
    };

    constexpr Config(
        const Direction direction,
        const Band band,
        const bool amplify)
        : tx(direction == Direction::Transmit),
          rx(direction == Direction::Receive),
          mix_bypass(band == Band::Mid),
          not_mix_bypass(band != Band::Mid),
          tx_mix_bp((direction == Direction::Transmit) && (band == Band::Mid)),
          rx_mix_bp((direction == Direction::Receive) && (band == Band::Mid)),
          hp(band == Band::High),
          lp(band == Band::Low),
          amp_bypass(!amplify),
          tx_amp((direction == Direction::Transmit) && amplify),
          not_tx_amp(!tx_amp),
          rx_amp((direction == Direction::Receive) && amplify),
          not_rx_amp(!rx_amp) {
    }

    constexpr Config()
        : Config(Direction::Receive, Band::Mid, false) {
    }

    constexpr Config(
        const base_type w)
        : w(w) {
    }

    constexpr Config operator^(const Config& r) const {
        return w ^ r.w;
    }

    constexpr Config operator&(const Config& r) const {
        return w & r.w;
    }

    constexpr bool operator[](const size_t n) const {
        return (w >> n) & 1;
    }

    static void gpio_init() {
        if (hackrf_r9) {
            gpio_r9_rx.output();
        } else {
            gpio_og_tx.output();
            gpio_og_rx.output();
        }
        for (auto gpio : gpios) {
            gpio.output();
        }
    }

    void apply() const {
        /* NOTE: Assumes order in gpios[] and Config bitfield match,
         * after the 'tx' and 'rx' fields which are handled specially. */
        for (size_t n = 0; n < gpios.size() + 2; n++) {
            bool value = (*this)[n];
            switch (n) {
                case 0:
                    if (!hackrf_r9) {
                        gpio_og_tx.write(value);
                    }
                    break;
                case 1:
                    if (hackrf_r9) {
                        gpio_r9_rx.write(value);
                    } else {
                        gpio_og_rx.write(value);
                    }
                    break;
                default:
                    gpios[n - 2].write(value);
                    break;
            }
        }
    }
};

/* HackRF One config table - not used on PRALINE */
using ConfigAmp = std::array<Config, 2>;
using ConfigDirection = std::array<ConfigAmp, 2>;
using ConfigBand = std::array<ConfigDirection, 3>;

constexpr ConfigAmp config_amp(
    const Direction direction,
    const Band band) {
    return {{
        Config(direction, band, false),
        Config(direction, band, true),
    }};
}

constexpr ConfigDirection config_rx_tx(
    const Band band) {
    return {
        config_amp(Direction::Receive, band),
        config_amp(Direction::Transmit, band),
    };
}

constexpr ConfigBand config_band() {
    return {
        config_rx_tx(Band::Low),
        config_rx_tx(Band::Mid),
        config_rx_tx(Band::High),
    };
}

constexpr ConfigBand config_table = config_band();

static_assert(sizeof(config_table) == sizeof(Config::base_type) * 3 * 2 * 2, "rf path config table unexpected size");

constexpr Config get_config(
    const Direction direction,
    const Band band,
    const bool amplify) {
    return config_table[toUType(band)][toUType(direction)][amplify ? 1 : 0];
}
#endif /* PRALINE */

} /* namespace */

void Path::init() {
#ifdef PRALINE
    PralineConfig::gpio_init();
    /* Set safe initial state: RX mode, mixer enabled, LPF on, amp off, no bias */
    PralineConfig config = {
        .tx_en = false,
        .mix_bypass = false,   // RF path mixer bypass (GPIO3[2])
        .lpf_en = true,        // LPF on for low band
        .rf_amp_en = false,    // Amp off
        .ant_bias_en_n = true  // Bias off (inverted)
    };
    config.apply();
#else
    update();
    Config::gpio_init();
#endif
}

void Path::set_direction(const Direction new_direction) {
    direction = new_direction;
    update();
}

void Path::set_band(const Band new_band) {
    band = new_band;
    _band = new_band;
    update();
}

void Path::set_rf_amp(const bool new_rf_amp) {
    rf_amp = new_rf_amp;
    update();
}

void Path::update() {
    /* 0 ^ 0 => 0 & 0 = 0 ^ 0 = 0 (no change)
     * 0 ^ 1 => 1 & 0 = 0 ^ 0 = 0 (ignore change to 1)
     * 1 ^ 0 => 1 & 1 = 1 ^ 1 = 0 (allow change to 0)
     * 1 ^ 1 => 0 & 1 = 0 ^ 1 = 1 (no change) */

#ifdef PRALINE
    /* PRALINE RF path control:
     * - tx_en: 1 for TX, 0 for RX
     * - mix_bypass: 0 to enable RF path mixer bypass (GPIO3[2])
     * - lpf_en: 1 for low band (< 2.4 GHz), 0 for high band
     * - rf_amp_en: 1 to enable RF amplifier
     * - ant_bias_en_n: 0 to enable antenna bias (inverted)
     */
    // const Config changed = _config ^ config_next;
    // const Config turned_off = _config & changed;

    PralineConfig config;

    /* In transition, ignore the bits that are turning on. So this transition phase
     * only turns off signals. It doesn't turn on signals.
     */
    // const Config transition_config = _config ^ turned_off;
    // update_signals(transition_config);

    config.tx_en = (direction == Direction::Transmit);

    // RF path mixer bypass: 0=enabled, 1=bypassed
    config.mix_bypass = (band == Band::Mid);

    /* Move to the final state by turning on required signals. */
    /* LPF for low band */

    config.lpf_en = (band == Band::Low);

    /* RF amp when amplification requested */
    config.rf_amp_en = rf_amp;

    /* Antenna bias off by default */
    config.ant_bias_en_n = true;

    config.apply();

#else
    /* HackRF One RF path control */
    const auto config = get_config(direction, band, rf_amp);
    config.apply();
#endif
}

}  // namespace path
}  // namespace rf