root/drivers/nvme/host/hwmon.c
// SPDX-License-Identifier: GPL-2.0
/*
 * NVM Express hardware monitoring support
 * Copyright (c) 2019, Guenter Roeck
 */

#include <linux/hwmon.h>
#include <linux/units.h>
#include <linux/unaligned.h>

#include "nvme.h"

struct nvme_hwmon_data {
        struct nvme_ctrl *ctrl;
        struct nvme_smart_log *log;
        struct mutex read_lock;
};

static int nvme_get_temp_thresh(struct nvme_ctrl *ctrl, int sensor, bool under,
                                long *temp)
{
        unsigned int threshold = sensor << NVME_TEMP_THRESH_SELECT_SHIFT;
        u32 status;
        int ret;

        if (under)
                threshold |= NVME_TEMP_THRESH_TYPE_UNDER;

        ret = nvme_get_features(ctrl, NVME_FEAT_TEMP_THRESH, threshold, NULL, 0,
                                &status);
        if (ret > 0)
                return -EIO;
        if (ret < 0)
                return ret;
        *temp = kelvin_to_millicelsius(status & NVME_TEMP_THRESH_MASK);

        return 0;
}

static int nvme_set_temp_thresh(struct nvme_ctrl *ctrl, int sensor, bool under,
                                long temp)
{
        unsigned int threshold = sensor << NVME_TEMP_THRESH_SELECT_SHIFT;
        int ret;

        temp = millicelsius_to_kelvin(temp);
        threshold |= clamp_val(temp, 0, NVME_TEMP_THRESH_MASK);

        if (under)
                threshold |= NVME_TEMP_THRESH_TYPE_UNDER;

        ret = nvme_set_features(ctrl, NVME_FEAT_TEMP_THRESH, threshold, NULL, 0,
                                NULL);
        if (ret > 0)
                return -EIO;

        return ret;
}

static int nvme_hwmon_get_smart_log(struct nvme_hwmon_data *data)
{
        return nvme_get_log(data->ctrl, NVME_NSID_ALL, NVME_LOG_SMART, 0,
                           NVME_CSI_NVM, data->log, sizeof(*data->log), 0);
}

static int nvme_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
                           u32 attr, int channel, long *val)
{
        struct nvme_hwmon_data *data = dev_get_drvdata(dev);
        struct nvme_smart_log *log = data->log;
        int temp;
        int err;

        /*
         * First handle attributes which don't require us to read
         * the smart log.
         */
        switch (attr) {
        case hwmon_temp_max:
                return nvme_get_temp_thresh(data->ctrl, channel, false, val);
        case hwmon_temp_min:
                return nvme_get_temp_thresh(data->ctrl, channel, true, val);
        case hwmon_temp_crit:
                *val = kelvin_to_millicelsius(data->ctrl->cctemp);
                return 0;
        default:
                break;
        }

        mutex_lock(&data->read_lock);
        err = nvme_hwmon_get_smart_log(data);
        if (err)
                goto unlock;

        switch (attr) {
        case hwmon_temp_input:
                if (!channel)
                        temp = get_unaligned_le16(log->temperature);
                else
                        temp = le16_to_cpu(log->temp_sensor[channel - 1]);
                *val = kelvin_to_millicelsius(temp);
                break;
        case hwmon_temp_alarm:
                *val = !!(log->critical_warning & NVME_SMART_CRIT_TEMPERATURE);
                break;
        default:
                err = -EOPNOTSUPP;
                break;
        }
unlock:
        mutex_unlock(&data->read_lock);
        return err;
}

static int nvme_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
                            u32 attr, int channel, long val)
{
        struct nvme_hwmon_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_temp_max:
                return nvme_set_temp_thresh(data->ctrl, channel, false, val);
        case hwmon_temp_min:
                return nvme_set_temp_thresh(data->ctrl, channel, true, val);
        default:
                break;
        }

        return -EOPNOTSUPP;
}

static const char * const nvme_hwmon_sensor_names[] = {
        "Composite",
        "Sensor 1",
        "Sensor 2",
        "Sensor 3",
        "Sensor 4",
        "Sensor 5",
        "Sensor 6",
        "Sensor 7",
        "Sensor 8",
};

static int nvme_hwmon_read_string(struct device *dev,
                                  enum hwmon_sensor_types type, u32 attr,
                                  int channel, const char **str)
{
        *str = nvme_hwmon_sensor_names[channel];
        return 0;
}

static umode_t nvme_hwmon_is_visible(const void *_data,
                                     enum hwmon_sensor_types type,
                                     u32 attr, int channel)
{
        const struct nvme_hwmon_data *data = _data;

        switch (attr) {
        case hwmon_temp_crit:
                if (!channel && data->ctrl->cctemp)
                        return 0444;
                break;
        case hwmon_temp_max:
        case hwmon_temp_min:
                if ((!channel && data->ctrl->wctemp) ||
                    (channel && data->log->temp_sensor[channel - 1] &&
                     !(data->ctrl->quirks &
                       NVME_QUIRK_NO_SECONDARY_TEMP_THRESH))) {
                        if (data->ctrl->quirks &
                            NVME_QUIRK_NO_TEMP_THRESH_CHANGE)
                                return 0444;
                        return 0644;
                }
                break;
        case hwmon_temp_alarm:
                if (!channel)
                        return 0444;
                break;
        case hwmon_temp_input:
        case hwmon_temp_label:
                if (!channel || data->log->temp_sensor[channel - 1])
                        return 0444;
                break;
        default:
                break;
        }
        return 0;
}

static const struct hwmon_channel_info *const nvme_hwmon_info[] = {
        HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_CRIT | HWMON_T_LABEL | HWMON_T_ALARM,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                                HWMON_T_LABEL),
        NULL
};

static const struct hwmon_ops nvme_hwmon_ops = {
        .is_visible     = nvme_hwmon_is_visible,
        .read           = nvme_hwmon_read,
        .read_string    = nvme_hwmon_read_string,
        .write          = nvme_hwmon_write,
};

static const struct hwmon_chip_info nvme_hwmon_chip_info = {
        .ops    = &nvme_hwmon_ops,
        .info   = nvme_hwmon_info,
};

int nvme_hwmon_init(struct nvme_ctrl *ctrl)
{
        struct device *dev = ctrl->device;
        struct nvme_hwmon_data *data;
        struct device *hwmon;
        int err;

        data = kzalloc_obj(*data);
        if (!data)
                return -ENOMEM;

        data->log = kzalloc_obj(*data->log);
        if (!data->log) {
                err = -ENOMEM;
                goto err_free_data;
        }

        data->ctrl = ctrl;
        mutex_init(&data->read_lock);

        err = nvme_hwmon_get_smart_log(data);
        if (err) {
                dev_warn(dev, "Failed to read smart log (error %d)\n", err);
                goto err_free_log;
        }

        hwmon = hwmon_device_register_with_info(dev, "nvme",
                                                data, &nvme_hwmon_chip_info,
                                                NULL);
        if (IS_ERR(hwmon)) {
                dev_warn(dev, "Failed to instantiate hwmon device\n");
                err = PTR_ERR(hwmon);
                goto err_free_log;
        }
        ctrl->hwmon_device = hwmon;
        return 0;

err_free_log:
        kfree(data->log);
err_free_data:
        kfree(data);
        return err;
}

void nvme_hwmon_exit(struct nvme_ctrl *ctrl)
{
        if (ctrl->hwmon_device) {
                struct nvme_hwmon_data *data =
                        dev_get_drvdata(ctrl->hwmon_device);

                hwmon_device_unregister(ctrl->hwmon_device);
                ctrl->hwmon_device = NULL;
                kfree(data->log);
                kfree(data);
        }
}