backend/genesys/motor.cpp

/* sane - Scanner Access Now Easy.

   Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>

   This file is part of the SANE package.

   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 of the
   License, 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.  If not, see <https://www.gnu.org/licenses/>.
*/

#define DEBUG_DECLARE_ONLY

#include "low.h"
#include "motor.h"
#include "utilities.h"
#include <cmath>
#include <numeric>

namespace genesys {

unsigned MotorSlope::get_table_step_shifted(unsigned step, StepType step_type) const
{
    // first two steps are always equal to the initial speed
    if (step < 2) {
        return initial_speed_w >> static_cast<unsigned>(step_type);
    }
    step--;

    float initial_speed_v = 1.0f / initial_speed_w;
    float speed_v = std::sqrt(initial_speed_v * initial_speed_v + 2 * acceleration * step);
    return static_cast<unsigned>(1.0f / speed_v) >> static_cast<unsigned>(step_type);
}

float compute_acceleration_for_steps(unsigned initial_w, unsigned max_w, unsigned steps)
{
    float initial_speed_v = 1.0f / static_cast<float>(initial_w);
    float max_speed_v = 1.0f / static_cast<float>(max_w);
    return (max_speed_v * max_speed_v - initial_speed_v * initial_speed_v) / (2 * steps);
}


MotorSlope MotorSlope::create_from_steps(unsigned initial_w, unsigned max_w,
                                         unsigned steps)
{
    MotorSlope slope;
    slope.initial_speed_w = initial_w;
    slope.max_speed_w = max_w;
    slope.acceleration = compute_acceleration_for_steps(initial_w, max_w, steps);
    return slope;
}

void MotorSlopeTable::slice_steps(unsigned count, unsigned step_multiplier)
{
    if (count > table.size() || count < step_multiplier) {
        throw SaneException("Invalid steps count");
    }
    count = align_multiple_floor(count, step_multiplier);
    table.resize(count);
    generate_pixeltime_sum();
}

void MotorSlopeTable::expand_table(unsigned count, unsigned step_multiplier)
{
    if (table.empty()) {
        throw SaneException("Can't expand empty table");
    }
    count = align_multiple_ceil(count, step_multiplier);
    table.resize(table.size() + count, table.back());
    generate_pixeltime_sum();
}

void MotorSlopeTable::generate_pixeltime_sum()
{
    pixeltime_sum_ = std::accumulate(table.begin(), table.end(),
                                     std::size_t{0}, std::plus<std::size_t>());
}

unsigned get_slope_table_max_size(AsicType asic_type)
{
    switch (asic_type) {
        case AsicType::GL646:
        case AsicType::GL841:
        case AsicType::GL842: return 255;
        case AsicType::GL843:
        case AsicType::GL845:
        case AsicType::GL846:
        case AsicType::GL847:
        case AsicType::GL124: return 1024;
        default:
            throw SaneException("Unknown asic type");
    }
}

MotorSlopeTable create_slope_table_for_speed(const MotorSlope& slope, unsigned target_speed_w,
                                             StepType step_type, unsigned steps_alignment,
                                             unsigned min_size, unsigned max_size)
{
    DBG_HELPER_ARGS(dbg, "target_speed_w: %d, step_type: %d, steps_alignment: %d, min_size: %d",
                    target_speed_w, static_cast<unsigned>(step_type), steps_alignment, min_size);
    MotorSlopeTable table;

    unsigned step_shift = static_cast<unsigned>(step_type);

    unsigned target_speed_shifted_w = target_speed_w >> step_shift;
    unsigned max_speed_shifted_w = slope.max_speed_w >> step_shift;

    if (target_speed_shifted_w < max_speed_shifted_w) {
        dbg.vlog(DBG_warn, "failed to reach target speed %d %d", target_speed_w,
                  slope.max_speed_w);
    }

    if (target_speed_shifted_w >= std::numeric_limits<std::uint16_t>::max()) {
        throw SaneException("Target motor speed is too low");
    }

    unsigned final_speed = std::max(target_speed_shifted_w, max_speed_shifted_w);

    table.table.reserve(max_size);

    while (table.table.size() < max_size - 1) {
        unsigned current = slope.get_table_step_shifted(table.table.size(), step_type);
        if (current <= final_speed) {
            break;
        }
        table.table.push_back(current);
    }

    // make sure the target speed (or the max speed if target speed is too high) is present in
    // the table
    table.table.push_back(final_speed);

    // fill the table up to the specified size
    while (table.table.size() < max_size - 1 &&
           (table.table.size() % steps_alignment != 0 || table.table.size() < min_size))
    {
        table.table.push_back(table.table.back());
    }

    table.generate_pixeltime_sum();

    return table;
}

std::ostream& operator<<(std::ostream& out, const MotorSlope& slope)
{
    out << "MotorSlope{\n"
        << "    initial_speed_w: " << slope.initial_speed_w << '\n'
        << "    max_speed_w: " << slope.max_speed_w << '\n'
        << "    a: " << slope.acceleration << '\n'
        << '}';
    return out;
}

std::ostream& operator<<(std::ostream& out, const MotorProfile& profile)
{
    out << "MotorProfile{\n"
        << "    max_exposure: " << profile.max_exposure << '\n'
        << "    step_type: " << profile.step_type << '\n'
        << "    motor_vref: " << profile.motor_vref << '\n'
        << "    resolutions: " << format_indent_braced_list(4, profile.resolutions) << '\n'
        << "    scan_methods: " << format_indent_braced_list(4, profile.scan_methods) << '\n'
        << "    slope: " << format_indent_braced_list(4, profile.slope) << '\n'
        << '}';
    return out;
}

std::ostream& operator<<(std::ostream& out, const Genesys_Motor& motor)
{
    out << "Genesys_Motor{\n"
        << "    id: " << motor.id << '\n'
        << "    base_ydpi: " << motor.base_ydpi << '\n'
        << "    profiles: "
        << format_indent_braced_list(4, format_vector_indent_braced(4, "MotorProfile",
                                                                    motor.profiles)) << '\n'
        << "    fast_profiles: "
        << format_indent_braced_list(4, format_vector_indent_braced(4, "MotorProfile",
                                                                    motor.fast_profiles)) << '\n'
        << '}';
    return out;
}

} // namespace genesys