/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009-2011 Nathan Whitehorn
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/systm.h>

#include <sys/types.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/reboot.h>
#include <sys/sysctl.h>
#include <sys/queue.h>

#include "powermac_thermal.h"

/* A 10 second timer for spinning down fans. */
#define FAN_HYSTERESIS_TIMER    10

static void fan_management_proc(void);
static void pmac_therm_manage_fans(void);

static struct proc *pmac_them_proc;
static int enable_pmac_thermal = 1;

static struct kproc_desc pmac_therm_kp = {
        "pmac_thermal",
        fan_management_proc,
        &pmac_them_proc
};

SYSINIT(pmac_therm_setup, SI_SUB_KTHREAD_IDLE, SI_ORDER_ANY, kproc_start,
    &pmac_therm_kp);
SYSCTL_INT(_machdep, OID_AUTO, manage_fans, CTLFLAG_RWTUN,
    &enable_pmac_thermal, 1, "Enable automatic fan management");
static MALLOC_DEFINE(M_PMACTHERM, "pmactherm", "Powermac Thermal Management");

struct pmac_fan_le {
        struct pmac_fan                 *fan;
        int                             last_val;
        int                             timer;
        SLIST_ENTRY(pmac_fan_le)        entries;
};
struct pmac_sens_le {
        struct pmac_therm               *sensor;
        int                             last_val;
#define MAX_CRITICAL_COUNT 6
        int                             critical_count;
        SLIST_ENTRY(pmac_sens_le)       entries;
};
static SLIST_HEAD(pmac_fans, pmac_fan_le) fans = SLIST_HEAD_INITIALIZER(fans);
static SLIST_HEAD(pmac_sensors, pmac_sens_le) sensors =
    SLIST_HEAD_INITIALIZER(sensors);

static void
fan_management_proc(void)
{
        /* Nothing to manage? */
        if (SLIST_EMPTY(&fans))
                kproc_exit(0);

        while (1) {
                pmac_therm_manage_fans();
                pause("pmac_therm", hz);
        }
}

static void
pmac_therm_manage_fans(void)
{
        struct pmac_sens_le *sensor;
        struct pmac_fan_le *fan;
        int average_excess, max_excess_zone, frac_excess;
        int fan_speed;
        int nsens, nsens_zone;
        int temp;

        if (!enable_pmac_thermal)
                return;

        /* Read all the sensors */
        SLIST_FOREACH(sensor, &sensors, entries) {
                temp = sensor->sensor->read(sensor->sensor);
                if (temp > 0) /* Use the previous temp in case of error */
                        sensor->last_val = temp;

                if (sensor->last_val > sensor->sensor->max_temp) {
                        sensor->critical_count++;
                        printf("WARNING: Current temperature (%s: %d.%d C) "
                            "exceeds critical temperature (%d.%d C); "
                            "count=%d\n",
                            sensor->sensor->name,
                            (sensor->last_val - ZERO_C_TO_K) / 10,
                            (sensor->last_val - ZERO_C_TO_K) % 10,
                            (sensor->sensor->max_temp - ZERO_C_TO_K) / 10,
                            (sensor->sensor->max_temp - ZERO_C_TO_K) % 10,
                            sensor->critical_count);
                        if (sensor->critical_count >= MAX_CRITICAL_COUNT) {
                                printf("WARNING: %s temperature exceeded "
                                    "critical temperature %d times in a row; "
                                    "shutting down!\n",
                                    sensor->sensor->name,
                                    sensor->critical_count);
                                shutdown_nice(RB_POWEROFF);
                        }
                } else {
                        if (sensor->critical_count > 0)
                                sensor->critical_count--;
                }
        }

        /* Set all the fans */
        SLIST_FOREACH(fan, &fans, entries) {
                nsens = nsens_zone = 0;
                average_excess = max_excess_zone = 0;
                SLIST_FOREACH(sensor, &sensors, entries) {
                        temp = imin(sensor->last_val,
                            sensor->sensor->max_temp);
                        frac_excess = (temp -
                            sensor->sensor->target_temp)*100 /
                            (sensor->sensor->max_temp - temp + 1);
                        if (frac_excess < 0)
                                frac_excess = 0;
                        if (sensor->sensor->zone == fan->fan->zone) {
                                max_excess_zone = imax(max_excess_zone,
                                    frac_excess);
                                nsens_zone++;
                        }
                        average_excess += frac_excess;
                        nsens++;
                }
                average_excess /= nsens;

                /* If there are no sensors in this zone, use the average */
                if (nsens_zone == 0)
                        max_excess_zone = average_excess;
                /* No sensors at all? Use default */
                if (nsens == 0) {
                        fan->fan->set(fan->fan, fan->fan->default_rpm);
                        continue;
                }

                /*
                 * Scale the fan linearly in the max temperature in its
                 * thermal zone.
                 */
                max_excess_zone = imin(max_excess_zone, 100);
                fan_speed = max_excess_zone * 
                    (fan->fan->max_rpm - fan->fan->min_rpm)/100 +
                    fan->fan->min_rpm;
                if (fan_speed >= fan->last_val) {
                    fan->timer = FAN_HYSTERESIS_TIMER;
                    fan->last_val = fan_speed;
                } else {
                    fan->timer--;
                    if (fan->timer == 0) {
                        fan->last_val = fan_speed;
                        fan->timer = FAN_HYSTERESIS_TIMER;
                    }
                }
                fan->fan->set(fan->fan, fan->last_val);
        }
}

void
pmac_thermal_fan_register(struct pmac_fan *fan)
{
        struct pmac_fan_le *list_entry;

        list_entry = malloc(sizeof(struct pmac_fan_le), M_PMACTHERM,
            M_ZERO | M_WAITOK);
        list_entry->fan = fan;

        SLIST_INSERT_HEAD(&fans, list_entry, entries);
}

void
pmac_thermal_sensor_register(struct pmac_therm *sensor)
{
        struct pmac_sens_le *list_entry;

        list_entry = malloc(sizeof(struct pmac_sens_le), M_PMACTHERM,
            M_ZERO | M_WAITOK);
        list_entry->sensor = sensor;
        list_entry->last_val = 0;
        list_entry->critical_count = 0;

        SLIST_INSERT_HEAD(&sensors, list_entry, entries);
}