targets.hpp

#pragma once

#include <experimental/filesystem>
#include <phosphor-logging/elog-errors.hpp>
#include <phosphor-logging/log.hpp>
#include <xyz/openbmc_project/Sensor/Device/error.hpp>
#include "fan_speed.hpp"
#include "fan_pwm.hpp"

/** @class Targets
 *  @brief Target type traits.
 *
 *  @tparam T - The target type.
 */
template <typename T>
struct Targets
{
    static void fail()
    {
        static_assert(sizeof(Targets) == -1, "Unsupported Target type");
    }
};

/**@brief Targets specialization for fan speed. */
template <>
struct Targets<hwmon::FanSpeed>
{
    static constexpr InterfaceType type = InterfaceType::FAN_SPEED;
};

template <>
struct Targets<hwmon::FanPwm>
{
    static constexpr InterfaceType type = InterfaceType::FAN_PWM;
};

/** @brief addTarget
 *
 *  Creates the target type interface
 *
 *  @tparam T - The target type
 *
 *  @param[in] sensor - A sensor type and name
 *  @param[in] ioAccess - hwmon sysfs access object
 *  @param[in] devPath - The /sys/devices sysfs path
 *  @param[in] info - The sdbusplus server connection and interfaces
 *
 *  @return A shared pointer to the target interface object
 *          Will be empty if no interface was created
 */
template <typename T>
std::shared_ptr<T> addTarget(const SensorSet::key_type& sensor,
                             const sysfs::hwmonio::HwmonIO& ioAccess,
                             const std::string& devPath,
                             ObjectInfo& info)
{
    std::shared_ptr<T> target;
    namespace fs = std::experimental::filesystem;
    static constexpr bool deferSignals = true;

    auto& bus = *std::get<sdbusplus::bus::bus*>(info);
    auto& obj = std::get<Object>(info);
    auto& objPath = std::get<std::string>(info);
    auto type = Targets<T>::type;

    // Check if target sysfs file exists
    std::string sysfsFullPath;
    std::string targetName = sensor.first;
    std::string targetId = sensor.second;
    std::string entry = hwmon::entry::target;

    using namespace std::literals;
    const std::string pwm = "pwm"s;
    const std::string empty = ""s;

    if (InterfaceType::FAN_PWM == type)
    {
        targetName = pwm;
        // If PWM_TARGET is set, use the specified pwm id
        auto id = getEnv("PWM_TARGET", sensor);
        if (!id.empty())
        {
            targetId = id;
        }
        entry = empty;
    }

    sysfsFullPath = sysfs::make_sysfs_path(ioAccess.path(),
                                           targetName,
                                           targetId,
                                           entry);
    if (fs::exists(sysfsFullPath))
    {
        uint32_t targetSpeed = 0;

        try
        {
            targetSpeed = ioAccess.read(
                targetName,
                targetId,
                entry,
                sysfs::hwmonio::retries,
                sysfs::hwmonio::delay);
        }
        catch (const std::system_error& e)
        {
            using namespace phosphor::logging;
            using namespace sdbusplus::xyz::openbmc_project::
                Sensor::Device::Error;
            using metadata = xyz::openbmc_project::Sensor::
                Device::ReadFailure;

            report<ReadFailure>(
                    metadata::CALLOUT_ERRNO(e.code().value()),
                    metadata::CALLOUT_DEVICE_PATH(devPath.c_str()));

            log<level::INFO>("Logging failing sysfs file",
                    phosphor::logging::entry(
                            "FILE=%s", sysfsFullPath.c_str()));
        }

        target = std::make_shared<T>(ioAccess.path(),
                                     devPath,
                                     targetId,
                                     bus,
                                     objPath.c_str(),
                                     deferSignals,
                                     targetSpeed);
        obj[type] = target;
    }

    return target;
}