/*-
 * Copyright (c) 2005 Nate Lawson
 * Copyright (c) 2000 Mitsuru IWASAKI <iwasaki@jp.freebsd.org>
 * 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.
 *
 * $FreeBSD: head/sys/dev/acpica/acpi_battery.c 227992 2011-11-26 13:43:50Z dumbbell $
 */

#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/bus.h>
#include <sys/sysctl.h>

#include "acpi.h"

#include <dev/acpica/acpivar.h>
#include <dev/acpica/acpiio.h>

/* Default seconds before re-sampling the battery state. */
#define ACPI_BATTERY_INFO_EXPIRE        5

static int      acpi_batteries_initted;
static int      acpi_battery_info_expire = ACPI_BATTERY_INFO_EXPIRE;
static struct   acpi_battinfo   acpi_battery_battinfo;
static struct   sysctl_ctx_list acpi_battery_sysctl_ctx;
static struct   sysctl_oid      *acpi_battery_sysctl_tree;

ACPI_SERIAL_DECL(battery, "ACPI generic battery");

static void acpi_reset_battinfo(struct acpi_battinfo *info);
static void acpi_battery_clean_str(char *str, int len);
static device_t acpi_battery_find_dev(u_int logical_unit);
static int acpi_battery_ioctl(u_long cmd, caddr_t addr, void *arg);
static int acpi_battery_sysctl(SYSCTL_HANDLER_ARGS);
static int acpi_battery_units_sysctl(SYSCTL_HANDLER_ARGS);
static int acpi_battery_init(void);

int
acpi_battery_register(device_t dev)
{
    int error;

    error = 0;
    ACPI_SERIAL_INIT(battery);
    ACPI_SERIAL_BEGIN(battery);
    if (!acpi_batteries_initted)
        error = acpi_battery_init();
    ACPI_SERIAL_END(battery);
    return (error);
}

int
acpi_battery_remove(device_t dev)
{

    return (0);
}

int
acpi_battery_get_units(void)
{
    devclass_t batt_dc;

    batt_dc = devclass_find("battery");
    if (batt_dc == NULL)
        return (0);
    return (devclass_get_count(batt_dc));
}

int
acpi_battery_get_info_expire(void)
{

    return (acpi_battery_info_expire);
}

/* Check _BST results for validity. */
int
acpi_battery_bst_valid(struct acpi_bst *bst)
{
    return (bst->state != ACPI_BATT_STAT_NOT_PRESENT &&
        bst->cap != ACPI_BATT_UNKNOWN && bst->volt != ACPI_BATT_UNKNOWN);
}

/* Check _BIF results for validity. */
int
acpi_battery_bif_valid(struct acpi_bif *bif)
{
    return (bif->lfcap != 0);
}

/* Get info about one or all batteries. */
int
acpi_battery_get_battinfo(device_t dev, struct acpi_battinfo *battinfo)
{
    int batt_stat, devcount, dev_idx, error, i;
    int total_cap, total_min, valid_rate, valid_units;
    devclass_t batt_dc;
    device_t batt_dev;
    struct acpi_bst *bst;
    struct acpi_bif *bif;
    struct acpi_battinfo *bi;

    /*
     * Get the battery devclass and max unit for battery devices.  If there
     * are none or error, return immediately.
     */
    batt_dc = devclass_find("battery");
    if (batt_dc == NULL)
        return (ENXIO);
    devcount = devclass_get_maxunit(batt_dc);
    if (devcount == 0)
        return (ENXIO);

    /*
     * Allocate storage for all _BST data, their derived battinfo data,
     * and the current battery's _BIF data.
     */
    bst = kmalloc(devcount * sizeof(*bst), M_TEMP, M_WAITOK | M_ZERO);
    bi = kmalloc(devcount * sizeof(*bi), M_TEMP, M_WAITOK | M_ZERO);
    bif = kmalloc(sizeof(*bif), M_TEMP, M_WAITOK | M_ZERO);

    /*
     * Pass 1:  for each battery that is present and valid, get its status,
     * calculate percent capacity remaining, and sum all the current
     * discharge rates.
     */
    dev_idx = -1;
    batt_stat = valid_rate = valid_units = 0;
    for (i = 0; i < devcount; i++) {
        /* Default info for every battery is "not present". */
        acpi_reset_battinfo(&bi[i]);

        /*
         * Find the device.  Since devcount is in terms of max units, this
         * may be a sparse array so skip devices that aren't present.
         */
        batt_dev = devclass_get_device(batt_dc, i);
        if (batt_dev == NULL)
            continue;

        /* If examining a specific battery and this is it, record its index. */
        if (dev != NULL && dev == batt_dev)
            dev_idx = i;

        /*
         * Be sure we can get various info from the battery.  Note that
         * acpi_BatteryIsPresent() is not enough because smart batteries only
         * return that the device is present.
         */
        if (!acpi_BatteryIsPresent(batt_dev) ||
            ACPI_BATT_GET_STATUS(batt_dev, &bst[i]) != 0 ||
            ACPI_BATT_GET_INFO(batt_dev, bif) != 0)
            continue;

        /* If a battery is not installed, we sometimes get strange values. */
        if (!acpi_battery_bst_valid(&bst[i]) ||
            !acpi_battery_bif_valid(bif))
            continue;

        /*
         * Record current state.  If both charging and discharging are set,
         * ignore the charging flag.
         */
        valid_units++;
        if ((bst[i].state & ACPI_BATT_STAT_DISCHARG) != 0)
            bst[i].state &= ~ACPI_BATT_STAT_CHARGING;
        batt_stat |= bst[i].state;
        bi[i].state = bst[i].state;

        /*
         * If the battery info is in terms of mA, convert to mW by
         * multiplying by the design voltage.  If the design voltage
         * is 0 (due to some error reading the battery), skip this
         * conversion.
         */
        if (bif->units == ACPI_BIF_UNITS_MA && bif->dvol != 0 && dev == NULL) {
            bst[i].rate = (bst[i].rate * bif->dvol) / 1000;
            bst[i].cap = (bst[i].cap * bif->dvol) / 1000;
            bif->lfcap = (bif->lfcap * bif->dvol) / 1000;
        }

        /*
         * The calculation above may set bif->lfcap to zero. This was
         * seen on a laptop with a broken battery. The result of the
         * division was rounded to zero.
         */
        if (!acpi_battery_bif_valid(bif))
            continue;

        /* Calculate percent capacity remaining. */
        bi[i].cap = (100 * bst[i].cap) / bif->lfcap;

        /*
         * Some laptops report the "design-capacity" instead of the
         * "real-capacity" when the battery is fully charged.  That breaks
         * the above arithmetic as it needs to be 100% maximum.
         */
        if (bi[i].cap > 100)
            bi[i].cap = 100;

        /*
         * Some DSDTs report a negative 16-bit value for the rate and/or
         * report 0 as 65536.
         */
        if (acpi_quirks & ACPI_Q_BATT_RATE_ABS &&
            bif->units == ACPI_BIF_UNITS_MA &&
            bst[i].rate != ACPI_BATT_UNKNOWN &&
            (int16_t)bst[i].rate < 0)
                bst[i].rate = abs((int16_t)bst[i].rate);

        /*
         * On systems with more than one battery, they may get used
         * sequentially, thus bst.rate may only signify the one currently
         * in use.  For the remaining batteries, bst.rate will be zero,
         * which makes it impossible to calculate the total remaining time.
         * Therefore, we sum the bst.rate for batteries in the discharging
         * state and use the sum to calculate the total remaining time.
         */
        if (bst[i].rate != ACPI_BATT_UNKNOWN &&
            (bst[i].state & ACPI_BATT_STAT_DISCHARG) != 0)
            valid_rate += bst[i].rate;
    }

    /* If the caller asked for a device but we didn't find it, error. */
    if (dev != NULL && dev_idx == -1) {
        error = ENXIO;
        goto out;
    }

    /* Pass 2:  calculate capacity and remaining time for all batteries. */
    total_cap = total_min = 0;
    for (i = 0; i < devcount; i++) {
        /*
         * If any batteries are discharging, use the sum of the bst.rate
         * values.  Otherwise, we are on AC power, and there is infinite
         * time remaining for this battery until we go offline.
         */
        if (valid_rate > 0)
            bi[i].min = (60 * bst[i].cap) / valid_rate;
        else
            bi[i].min = 0;
        total_min += bi[i].min;

        /* If this battery is not present, don't use its capacity. */
        if (bi[i].cap != -1)
            total_cap += bi[i].cap;
    }

    /*
     * Return total battery percent and time remaining.  If there are
     * no valid batteries, report values as unknown.
     */
    if (valid_units > 0) {
        if (dev == NULL) {
            battinfo->cap = total_cap / valid_units;
            battinfo->min = total_min;
            battinfo->state = batt_stat;
            battinfo->rate = valid_rate;
        } else {
            battinfo->cap = bi[dev_idx].cap;
            battinfo->min = bi[dev_idx].min;
            battinfo->state = bi[dev_idx].state;
            battinfo->rate = bst[dev_idx].rate;
        }

        /*
         * If the queried battery has no discharge rate or is charging,
         * report that we don't know the remaining time.
         */
        if (valid_rate == 0 || (battinfo->state & ACPI_BATT_STAT_CHARGING))
            battinfo->min = -1;
    } else
        acpi_reset_battinfo(battinfo);

    error = 0;

out:
    if (bi)
        kfree(bi, M_TEMP);
    if (bif)
        kfree(bif, M_TEMP);
    if (bst)
        kfree(bst, M_TEMP);
    return (error);
}

static void
acpi_reset_battinfo(struct acpi_battinfo *info)
{
    info->cap = -1;
    info->min = -1;
    info->state = ACPI_BATT_STAT_NOT_PRESENT;
    info->rate = -1;
}

/* Make string printable, removing invalid chars. */
static void
acpi_battery_clean_str(char *str, int len)
{
    int i;

    for (i = 0; i < len && *str != '\0'; i++, str++) {
        if (!isprint(*str))
            *str = '?';
    }

    /* NUL-terminate the string if we reached the end. */
    if (i == len)
        *str = '\0';
}

/*
 * The battery interface deals with devices and methods but userland
 * expects a logical unit number.  Convert a logical unit to a device_t.
 */
static device_t
acpi_battery_find_dev(u_int logical_unit)
{
    int found_unit, i, maxunit;
    device_t dev;
    devclass_t batt_dc;

    dev = NULL;
    found_unit = 0;
    batt_dc = devclass_find("battery");
    maxunit = devclass_get_maxunit(batt_dc);
    for (i = 0; i < maxunit; i++) {
        dev = devclass_get_device(batt_dc, i);
        if (dev == NULL)
            continue;
        if (logical_unit == found_unit)
            break;
        found_unit++;
        dev = NULL;
    }

    return (dev);
}

static int
acpi_battery_ioctl(u_long cmd, caddr_t addr, void *arg)
{
    union acpi_battery_ioctl_arg *ioctl_arg;
    int error, unit;
    device_t dev;

    /* For commands that use the ioctl_arg struct, validate it first. */
    error = ENXIO;
    unit = 0;
    dev = NULL;
    ioctl_arg = NULL;
    if (IOCPARM_LEN(cmd) == sizeof(*ioctl_arg)) {
        ioctl_arg = (union acpi_battery_ioctl_arg *)addr;
        unit = ioctl_arg->unit;
        if (unit != ACPI_BATTERY_ALL_UNITS)
            dev = acpi_battery_find_dev(unit);
    }

    /*
     * No security check required: information retrieval only.  If
     * new functions are added here, a check might be required.
     */
    switch (cmd) {
    case ACPIIO_BATT_GET_UNITS:
        *(int *)addr = acpi_battery_get_units();
        error = 0;
        break;
    case ACPIIO_BATT_GET_BATTINFO:
        if (dev != NULL || unit == ACPI_BATTERY_ALL_UNITS) {
            bzero(&ioctl_arg->battinfo, sizeof(ioctl_arg->battinfo));
            error = acpi_battery_get_battinfo(dev, &ioctl_arg->battinfo);
        }
        break;
    case ACPIIO_BATT_GET_BIF:
        if (dev != NULL) {
            bzero(&ioctl_arg->bif, sizeof(ioctl_arg->bif));
            error = ACPI_BATT_GET_INFO(dev, &ioctl_arg->bif);

            /*
             * Remove invalid characters.  Perhaps this should be done
             * within a convenience function so all callers get the
             * benefit.
             */
            acpi_battery_clean_str(ioctl_arg->bif.model,
                sizeof(ioctl_arg->bif.model));
            acpi_battery_clean_str(ioctl_arg->bif.serial,
                sizeof(ioctl_arg->bif.serial));
            acpi_battery_clean_str(ioctl_arg->bif.type,
                sizeof(ioctl_arg->bif.type));
            acpi_battery_clean_str(ioctl_arg->bif.oeminfo,
                sizeof(ioctl_arg->bif.oeminfo));
        }
        break;
    case ACPIIO_BATT_GET_BST:
        if (dev != NULL) {
            bzero(&ioctl_arg->bst, sizeof(ioctl_arg->bst));
            error = ACPI_BATT_GET_STATUS(dev, &ioctl_arg->bst);
        }
        break;
    default:
        error = EINVAL;
    }

    return (error);
}

static int
acpi_battery_sysctl(SYSCTL_HANDLER_ARGS)
{
    int val, error;

    acpi_battery_get_battinfo(NULL, &acpi_battery_battinfo);
    val = *(u_int *)oidp->oid_arg1;
    error = sysctl_handle_int(oidp, &val, 0, req);
    return (error);
}

static int
acpi_battery_units_sysctl(SYSCTL_HANDLER_ARGS)
{
    int count, error;

    count = acpi_battery_get_units();
    error = sysctl_handle_int(oidp, &count, 0, req);
    return (error);
}

static int
acpi_battery_init(void)
{
    struct acpi_softc   *sc;
    device_t             dev;
    int                  error;

    ACPI_SERIAL_ASSERT(battery);

    error = ENXIO;
    dev = devclass_get_device(devclass_find("acpi"), 0);
    if (dev == NULL)
        goto out;
    sc = device_get_softc(dev);

    error = acpi_register_ioctl(ACPIIO_BATT_GET_UNITS, acpi_battery_ioctl,
        NULL);
    if (error != 0)
        goto out;
    error = acpi_register_ioctl(ACPIIO_BATT_GET_BATTINFO, acpi_battery_ioctl,
        NULL);
    if (error != 0)
        goto out;
    error = acpi_register_ioctl(ACPIIO_BATT_GET_BIF, acpi_battery_ioctl, NULL);
    if (error != 0)
        goto out;
    error = acpi_register_ioctl(ACPIIO_BATT_GET_BST, acpi_battery_ioctl, NULL);
    if (error != 0)
        goto out;

    sysctl_ctx_init(&acpi_battery_sysctl_ctx);
    acpi_battery_sysctl_tree = SYSCTL_ADD_NODE(&acpi_battery_sysctl_ctx,
        SYSCTL_CHILDREN(sc->acpi_sysctl_tree), OID_AUTO, "battery", CTLFLAG_RD,
        0, "battery status and info");
    SYSCTL_ADD_PROC(&acpi_battery_sysctl_ctx,
        SYSCTL_CHILDREN(acpi_battery_sysctl_tree),
        OID_AUTO, "life", CTLTYPE_INT | CTLFLAG_RD,
        &acpi_battery_battinfo.cap, 0, acpi_battery_sysctl, "I",
        "percent capacity remaining");
    SYSCTL_ADD_PROC(&acpi_battery_sysctl_ctx,
        SYSCTL_CHILDREN(acpi_battery_sysctl_tree),
        OID_AUTO, "time", CTLTYPE_INT | CTLFLAG_RD,
        &acpi_battery_battinfo.min, 0, acpi_battery_sysctl, "I",
        "remaining time in minutes");
    SYSCTL_ADD_PROC(&acpi_battery_sysctl_ctx,
        SYSCTL_CHILDREN(acpi_battery_sysctl_tree),
        OID_AUTO, "state", CTLTYPE_INT | CTLFLAG_RD,
        &acpi_battery_battinfo.state, 0, acpi_battery_sysctl, "I",
        "current status flags");
    SYSCTL_ADD_PROC(&acpi_battery_sysctl_ctx,
        SYSCTL_CHILDREN(acpi_battery_sysctl_tree),
        OID_AUTO, "units", CTLTYPE_INT | CTLFLAG_RD,
        NULL, 0, acpi_battery_units_sysctl, "I", "number of batteries");
    SYSCTL_ADD_INT(&acpi_battery_sysctl_ctx,
        SYSCTL_CHILDREN(acpi_battery_sysctl_tree),
        OID_AUTO, "info_expire", CTLFLAG_RW,
        &acpi_battery_info_expire, 0,
        "time in seconds until info is refreshed");

    acpi_batteries_initted = TRUE;

out:
    if (error != 0) {
        acpi_deregister_ioctl(ACPIIO_BATT_GET_UNITS, acpi_battery_ioctl);
        acpi_deregister_ioctl(ACPIIO_BATT_GET_BATTINFO, acpi_battery_ioctl);
        acpi_deregister_ioctl(ACPIIO_BATT_GET_BIF, acpi_battery_ioctl);
        acpi_deregister_ioctl(ACPIIO_BATT_GET_BST, acpi_battery_ioctl);
    }
    return (error);
}