/*      $NetBSD: apple_smc_temp.c,v 1.7 2023/08/08 05:20:14 mrg Exp $   */

/*
 * Apple System Management Controller: Temperature Sensors
 */

/*-
 * Copyright (c) 2013 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Taylor R. Campbell.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: apple_smc_temp.c,v 1.7 2023/08/08 05:20:14 mrg Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/systm.h>

#include <dev/ic/apple_smc.h>

#include <dev/sysmon/sysmonvar.h>

struct apple_smc_temp_softc {
        device_t                sc_dev;
        struct apple_smc_tag    *sc_smc;
        struct sysmon_envsys    *sc_sme;
        struct {
                struct apple_smc_key    *sensor_key;
                struct envsys_data      sensor_data;
        }                       *sc_sensors;
        size_t                  sc_nsensors;
};

static int      apple_smc_temp_match(device_t, cfdata_t, void *);
static void     apple_smc_temp_attach(device_t, device_t, void *);
static int      apple_smc_temp_detach(device_t, int);
static void     apple_smc_temp_refresh(struct sysmon_envsys *,
                    struct envsys_data *);
static int      apple_smc_temp_count_sensors(struct apple_smc_tag *,
                    uint32_t *);
static void     apple_smc_temp_count_sensors_scanner(struct apple_smc_tag *,
                    void *, struct apple_smc_key *);
static int      apple_smc_temp_find_sensors(struct apple_smc_temp_softc *);
static int      apple_smc_temp_find_sensors_init(struct apple_smc_tag *,
                    void *, uint32_t);
static void     apple_smc_temp_find_sensors_scanner(struct apple_smc_tag *,
                    void *, struct apple_smc_key *);
static void     apple_smc_temp_release_keys(struct apple_smc_temp_softc *);
static int      apple_smc_scan_temp_sensors(struct apple_smc_tag *, void *,
                    int (*)(struct apple_smc_tag *, void *, uint32_t),
                    void (*)(struct apple_smc_tag *, void *,
                        struct apple_smc_key *));
static int      apple_smc_bound_temp_sensors(struct apple_smc_tag *,
                    uint32_t *, uint32_t *);
static bool     apple_smc_temp_sensor_p(const struct apple_smc_key *);

CFATTACH_DECL_NEW(apple_smc_temp, sizeof(struct apple_smc_temp_softc),
    apple_smc_temp_match, apple_smc_temp_attach, apple_smc_temp_detach, NULL);

static int
apple_smc_temp_match(device_t parent, cfdata_t match, void *aux)
{
        const struct apple_smc_attach_args *const asa = aux;
        uint32_t nsensors;
        int error;

        /* Find how many temperature sensors we have. */
        error = apple_smc_temp_count_sensors(asa->asa_smc, &nsensors);
        if (error)
                return 0;

        /* If there aren't any, don't bother attaching.  */
        if (nsensors == 0)
                return 0;

        return 1;
}

static void
apple_smc_temp_attach(device_t parent, device_t self, void *aux)
{
        struct apple_smc_temp_softc *const sc = device_private(self);
        const struct apple_smc_attach_args *const asa = aux;
        int error;

        /* Identify ourselves.  */
        aprint_normal(": Apple SMC temperature sensors\n");

        /* Initialize the softc. */
        sc->sc_dev = self;
        sc->sc_smc = asa->asa_smc;

        /* Create a sysmon_envsys record, but don't register it yet.  */
        sc->sc_sme = sysmon_envsys_create();
        sc->sc_sme->sme_name = device_xname(self);
        sc->sc_sme->sme_cookie = sc;
        sc->sc_sme->sme_refresh = apple_smc_temp_refresh;

        /* Find and attach all the sensors.  */
        error = apple_smc_temp_find_sensors(sc);
        if (error) {
                aprint_error_dev(self, "failed to find sensors: %d\n", error);
                goto fail;
        }

        /* Sensors are all attached.  Register with sysmon_envsys now.  */
        error = sysmon_envsys_register(sc->sc_sme);
        if (error) {
                aprint_error_dev(self, "failed to register with sysmon_envsys:"
                    " %d\n", error);
                goto fail;
        }

        /* Success!  */
        return;

fail:   sysmon_envsys_destroy(sc->sc_sme);
        sc->sc_sme = NULL;
}

static int
apple_smc_temp_detach(device_t self, int flags)
{
        struct apple_smc_temp_softc *const sc = device_private(self);

        /* If we registered with sysmon_envsys, unregister.  */
        if (sc->sc_sme != NULL) {
                sysmon_envsys_unregister(sc->sc_sme);

                KASSERT(sc->sc_sensors != NULL);
                KASSERT(sc->sc_nsensors > 0);

                /* Release the keys and free the memory for sensor records.  */
                apple_smc_temp_release_keys(sc);
                kmem_free(sc->sc_sensors,
                    (sizeof(sc->sc_sensors[0]) * sc->sc_nsensors));
                sc->sc_sensors = NULL;
                sc->sc_nsensors = 0;
        }

        /* Success!  */
        return 0;
}

static void
apple_smc_temp_refresh(struct sysmon_envsys *sme, struct envsys_data *edata)
{
        struct apple_smc_temp_softc *const sc = sme->sme_cookie;
        const struct apple_smc_key *key;
        uint16_t utemp16;
        int32_t temp;
        int error;

        /* Sanity-check the sensor number out of paranoia.  */
        if (edata->sensor >= sc->sc_nsensors) {
                aprint_error_dev(sc->sc_dev, "unknown sensor %"PRIu32"\n",
                    edata->sensor);
                return;
        }

        /* Read the raw temperature sensor value.  */
        key = sc->sc_sensors[edata->sensor].sensor_key;
        KASSERT(key != NULL);
        error = apple_smc_read_key_2(sc->sc_smc, key, &utemp16);
        if (error) {
                aprint_error_dev(sc->sc_dev,
                    "failed to read temperature sensor %"PRIu32" (%s): %d\n",
                    edata->sensor, apple_smc_key_name(key), error);
                edata->state = ENVSYS_SINVALID;
                return;
        }

        /* Sign-extend, in case we ever get below freezing...  */
        temp = (int16_t)utemp16;

        /* Convert to `millicentigrade'.  */
        temp *= 250;
        temp >>= 6;

        /* Convert to millikelvins.  */
        temp += 273150;

        /* Finally, convert to microkelvins as sysmon_envsys wants.  */
        temp *= 1000;

        /* Success!  */
        edata->value_cur = temp;
        edata->state = ENVSYS_SVALID;
}

static int
apple_smc_temp_count_sensors(struct apple_smc_tag *smc, uint32_t *nsensors)
{

        /* Start with zero sensors.  */
        *nsensors = 0;

        /* Count 'em.  */
        return apple_smc_scan_temp_sensors(smc, nsensors,
            NULL,
            &apple_smc_temp_count_sensors_scanner);
}

static void
apple_smc_temp_count_sensors_scanner(struct apple_smc_tag *smc, void *arg,
    struct apple_smc_key *key)
{
        uint32_t *const nsensors = arg;

        (*nsensors)++;
        apple_smc_release_key(smc, key);
}

struct fss {                    /* Find Sensors State */
        struct apple_smc_temp_softc     *fss_sc;
        unsigned int                    fss_sensor;
};

static int
apple_smc_temp_find_sensors(struct apple_smc_temp_softc *sc)
{
        struct fss fss;
        int error;

        /* Start with zero sensors.  */
        fss.fss_sc = sc;
        fss.fss_sensor = 0;

        /* Find 'em.  */
        error = apple_smc_scan_temp_sensors(sc->sc_smc, &fss,
            &apple_smc_temp_find_sensors_init,
            &apple_smc_temp_find_sensors_scanner);
        if (error)
                return error;

        /*
         * Success guarantees that sc->sc_nsensors will be nonzero and
         * sc->sc_sensors will be allocated.
         */
        KASSERT(sc->sc_sensors != NULL);
        KASSERT(sc->sc_nsensors > 0);

        /* If we didn't find any sensors, bail.  */
        if (fss.fss_sensor == 0) {
                kmem_free(sc->sc_sensors, sc->sc_nsensors);
                sc->sc_sensors = NULL;
                sc->sc_nsensors = 0;
                return EIO;
        }

        /* Shrink the array if we overshot.  */
        if (fss.fss_sensor < sc->sc_nsensors) {
                void *const sensors = kmem_alloc((fss.fss_sensor *
                        sizeof(sc->sc_sensors[0])), KM_SLEEP);

                (void)memcpy(sensors, sc->sc_sensors,
                    (fss.fss_sensor * sizeof(sc->sc_sensors[0])));
                kmem_free(sc->sc_sensors, sc->sc_nsensors);
                sc->sc_sensors = sensors;
                sc->sc_nsensors = fss.fss_sensor;
        }

        /* Success!  */
        return 0;
}

static int
apple_smc_temp_find_sensors_init(struct apple_smc_tag *smc, void *arg,
    uint32_t nsensors)
{
        struct fss *const fss = arg;

        /* Record the maximum number of sensors we may have.  */
        fss->fss_sc->sc_nsensors = nsensors;

        /* If we found a maximum of zero sensors, bail.  */
        if (nsensors == 0) {
                fss->fss_sc->sc_sensors = NULL;
                return EIO;
        }

        /*
         * If there may be any sensors, optimistically allocate as many
         * records for them as we may possibly need.
         */
        fss->fss_sc->sc_sensors = kmem_alloc((nsensors *
                sizeof(fss->fss_sc->sc_sensors[0])), KM_SLEEP);

        /* Success!  */
        return 0;
}

static void
apple_smc_temp_find_sensors_scanner(struct apple_smc_tag *smc, void *arg,
    struct apple_smc_key *key)
{
        struct fss *const fss = arg;
        const uint32_t sensor = fss->fss_sensor;
        struct envsys_data *const edata =
            &fss->fss_sc->sc_sensors[sensor].sensor_data;
        int error;

        /* Initialize the envsys_data record for this temperature sensor.  */
        edata->units = ENVSYS_STEMP;
        edata->state = ENVSYS_SINVALID;
        edata->flags = ENVSYS_FHAS_ENTROPY;

        /*
         * Use the SMC key name as the temperature sensor's name.
         *
         * XXX We ought to use a more meaningful name based on a table
         * of known temperature sensors.
         */
        CTASSERT(sizeof(edata->desc) >= 4);
        (void)strlcpy(edata->desc, apple_smc_key_name(key), 4);

        /* Attach this temperature sensor to sysmon_envsys.  */
        error = sysmon_envsys_sensor_attach(fss->fss_sc->sc_sme, edata);
        if (error) {
                aprint_error_dev(fss->fss_sc->sc_dev,
                    "failed to attach temperature sensor %s: %d\n",
                    apple_smc_key_name(key), error);
                return;
        }

        /* Success!  */
        fss->fss_sc->sc_sensors[sensor].sensor_key = key;
        fss->fss_sensor++;
}

static void
apple_smc_temp_release_keys(struct apple_smc_temp_softc *sc)
{
        uint32_t sensor;

        for (sensor = 0; sensor < sc->sc_nsensors; sensor++) {
                KASSERT(sc->sc_sensors[sensor].sensor_key != NULL);
                apple_smc_release_key(sc->sc_smc,
                    sc->sc_sensors[sensor].sensor_key);
        }
}

static int
apple_smc_scan_temp_sensors(struct apple_smc_tag *smc, void *arg,
    int (*init)(struct apple_smc_tag *, void *, uint32_t),
    void (*scanner)(struct apple_smc_tag *, void *, struct apple_smc_key *))
{
        uint32_t tstart, ustart, i;
        struct apple_smc_key *key;
        int error;

        /* Find [start, end) bounds on the temperature sensor key indices.  */
        error = apple_smc_bound_temp_sensors(smc, &tstart, &ustart);
        if (error)
                return error;
        KASSERT(tstart <= ustart);

        /* Inform the caller of the number of candidates.  */
        if (init != NULL) {
                error = (*init)(smc, arg, (ustart - tstart));
                if (error)
                        return error;
        }

        /* Take a closer look at all the candidates.  */
        for (i = tstart; i < ustart; i++) {
                error = apple_smc_nth_key(smc, i, NULL, &key);
                if (error)
                        continue;

                /* Skip it if it's not a temperature sensor.  */
                if (!apple_smc_temp_sensor_p(key)) {
                        apple_smc_release_key(smc, key);
                        continue;
                }

                /* Scan it if it is one.  */
                (*scanner)(smc, arg, key);
        }

        /* Success!  */
        return 0;
}

static bool
apple_smc_temp_sensor_p(const struct apple_smc_key *key)
{

        /* It's a temperature sensor iff its type is sp78.  */
        return (0 == memcmp(apple_smc_key_desc(key)->asd_type,
                APPLE_SMC_TYPE_SP78, 4));
}

static int
apple_smc_bound_temp_sensors(struct apple_smc_tag *smc, uint32_t *tstart,
    uint32_t *ustart)
{
        int error;

        /* Find the first `T...' key.  */
        error = apple_smc_key_search(smc, "T\0\0\0", tstart);
        if (error)
                return error;

        /* Find the first `U...' key.  */
        error = apple_smc_key_search(smc, "U\0\0\0", ustart);
        if (error)
                return error;

        /* Sanity check: `T...' keys had better precede `U...' keys.  */
        if (!(*tstart <= *ustart))
                return EIO;

        /* Success!  */
        return 0;
}

MODULE(MODULE_CLASS_DRIVER, apple_smc_temp, "apple_smc,sysmon_envsys");

#ifdef _MODULE
#include "ioconf.c"
#endif

static int
apple_smc_temp_modcmd(modcmd_t cmd, void *arg __unused)
{
#ifdef _MODULE
        int error;
#endif

        switch (cmd) {
        case MODULE_CMD_INIT:
#ifdef _MODULE
                error = config_init_component(cfdriver_ioconf_apple_smc_temp,
                    cfattach_ioconf_apple_smc_temp,
                    cfdata_ioconf_apple_smc_temp);
                if (error)
                        return error;
#endif
                return 0;

        case MODULE_CMD_FINI:
#ifdef _MODULE
                error = config_fini_component(cfdriver_ioconf_apple_smc_temp,
                    cfattach_ioconf_apple_smc_temp,
                    cfdata_ioconf_apple_smc_temp);
                if (error)
                        return error;
#endif
                return 0;

        default:
                return ENOTTY;
        }
}