/*-
 * Copyright (c) 2015 M. Warner Losh <imp@FreeBSD.org>
 *
 * 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 unmodified, 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 ``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 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/systm.h>
#include <sys/kernel.h>

#include <sys/bus.h>
#include <sys/errno.h>
#include <sys/libkern.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sysctl.h>

#include <dev/ow/ow.h>
#include <dev/ow/own.h>

#define OWT_DS1820      0x10            /* Also 18S20 */
#define OWT_DS1822      0x22            /* Very close to 18B20 */
#define OWT_DS18B20     0x28            /* Also MAX31820 */
#define OWT_DS1825      0x3B            /* Just like 18B20 with address bits */

#define CONVERT_T               0x44
#define COPY_SCRATCHPAD         0x48
#define WRITE_SCRATCHPAD        0x4e
#define READ_POWER_SUPPLY       0xb4
#define RECALL_EE               0xb8
#define READ_SCRATCHPAD         0xbe

#define OW_TEMP_DONE            0x01
#define OW_TEMP_RUNNING         0x02

struct ow_temp_softc
{
        device_t        dev;
        int             type;
        int             temp;
        int             flags;
        int             bad_crc;
        int             bad_reads;
        int             reading_interval;
        int             parasite;
        struct mtx      temp_lock;
        struct proc     *event_thread;
};

static int
ow_temp_probe(device_t dev)
{

        switch (ow_get_family(dev)) {
        case OWT_DS1820:
                device_set_desc(dev, "One Wire Temperature");
                return BUS_PROBE_DEFAULT;
        case OWT_DS1822:
        case OWT_DS1825:
        case OWT_DS18B20:
                device_set_desc(dev, "Advanced One Wire Temperature");
                return BUS_PROBE_DEFAULT;
        default:
                return ENXIO;
        }
}

static int
ow_temp_read_scratchpad(device_t dev, uint8_t *scratch, int len)
{
        struct ow_cmd cmd;

        own_self_command(dev, &cmd, READ_SCRATCHPAD);
        cmd.xpt_read_len = len;
        own_command_wait(dev, &cmd);
        memcpy(scratch, cmd.xpt_read, len);

        return 0;
}

static int
ow_temp_convert_t(device_t dev)
{
        struct ow_cmd cmd;

        own_self_command(dev, &cmd, CONVERT_T);
        own_command_wait(dev, &cmd);

        return 0;
}

static int
ow_temp_read_power_supply(device_t dev, int *parasite)
{
        struct ow_cmd cmd;

        own_self_command(dev, &cmd, READ_POWER_SUPPLY);
        cmd.flags |= OW_FLAG_READ_BIT;
        cmd.xpt_read_len = 1;
        own_command_wait(dev, &cmd);
        *parasite = !cmd.xpt_read[0];   /* parasites pull bus low */

        return 0;
}

static void
ow_temp_event_thread(void *arg)
{
        struct ow_temp_softc *sc;
        uint8_t scratch[8 + 1];
        uint8_t crc;
        int retries, rv, tmp;

        sc = arg;
        pause("owtstart", device_get_unit(sc->dev) * hz / 100); // 10ms stagger
        mtx_lock(&sc->temp_lock);
        sc->flags |= OW_TEMP_RUNNING;
        mtx_unlock(&sc->temp_lock);
        ow_temp_read_power_supply(sc->dev, &sc->parasite);
        if (sc->parasite)
                device_printf(sc->dev, "Running in parasitic mode unsupported\n");
        mtx_lock(&sc->temp_lock);
        while ((sc->flags & OW_TEMP_DONE) == 0) {
                mtx_unlock(&sc->temp_lock);
                ow_temp_convert_t(sc->dev);
                mtx_lock(&sc->temp_lock);
                msleep(sc, &sc->temp_lock, 0, "owtcvt", hz);
                if (sc->flags & OW_TEMP_DONE)
                        break;
                mtx_unlock(&sc->temp_lock);
                for (retries = 5; retries > 0; retries--) {
                        rv = ow_temp_read_scratchpad(sc->dev, scratch, sizeof(scratch));
                        if (rv == 0) {
                                crc = own_crc(sc->dev, scratch, sizeof(scratch) - 1);
                                if (crc == scratch[8]) {
                                        if (sc->type == OWT_DS1820) {
                                                if (scratch[7]) {
                                                        /*
                                                         * Formula from DS18S20 datasheet, page 6
                                                         * DS18S20 datasheet says count_per_c is 16, DS1820 does not
                                                         */
                                                        tmp = (int16_t)((scratch[0] & 0xfe) |
                                                            (scratch[1] << 8)) << 3;
                                                        tmp += 16 - scratch[6] - 4; /* count_per_c == 16 */
                                                } else
                                                        tmp = (int16_t)(scratch[0] | (scratch[1] << 8)) << 3;
                                        } else
                                                tmp = (int16_t)(scratch[0] | (scratch[1] << 8));
                                        sc->temp = tmp * 1000 / 16 + 273150;
                                        break;
                                }
                                sc->bad_crc++;
                        } else
                                sc->bad_reads++;
                }
                mtx_lock(&sc->temp_lock);
                msleep(sc, &sc->temp_lock, 0, "owtcvt", sc->reading_interval);
        }
        sc->flags &= ~OW_TEMP_RUNNING;
        mtx_unlock(&sc->temp_lock);
        kproc_exit(0);
}

static int
ow_temp_attach(device_t dev)
{
        struct ow_temp_softc *sc;

        sc = device_get_softc(dev);
        sc->dev = dev;
        sc->type = ow_get_family(dev);
        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "temperature",
            CTLFLAG_RD | CTLTYPE_INT | CTLFLAG_NEEDGIANT,
            &sc->temp, 0, sysctl_handle_int,
            "IK3", "Current Temperature");
        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "badcrc", CTLFLAG_RD,
            &sc->bad_crc, 0,
            "Number of Bad CRC on reading scratchpad");
        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "badread", CTLFLAG_RD,
            &sc->bad_reads, 0,
            "Number of errors on reading scratchpad");
        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "reading_interval", CTLFLAG_RW,
            &sc->reading_interval, 0,
            "ticks between reads");
        SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "parasite", CTLFLAG_RW,
            &sc->parasite, 0,
            "In Parasite mode");
        /*
         * Just do this for unit 0 to avoid locking
         * the ow bus until that code can be put
         * into place.
         */
        sc->temp = -1;
        sc->reading_interval = 10 * hz;
        mtx_init(&sc->temp_lock, "lock for doing temperature", NULL, MTX_DEF);
        /* Start the thread */
        if (kproc_create(ow_temp_event_thread, sc, &sc->event_thread, 0, 0,
            "%s event thread", device_get_nameunit(dev))) {
                device_printf(dev, "unable to create event thread.\n");
                panic("ow_temp_attach, can't create thread");
        }

        return 0;
}

static int
ow_temp_detach(device_t dev)
{
        struct ow_temp_softc *sc;

        sc = device_get_softc(dev);

        /*
         * Wait for the thread to die.  kproc_exit will do a wakeup
         * on the event thread's struct thread * so that we know it is
         * safe to proceed.  IF the thread is running, set the please
         * die flag and wait for it to comply.  Since the wakeup on
         * the event thread happens only in kproc_exit, we don't
         * need to loop here.
         */
        mtx_lock(&sc->temp_lock);
        sc->flags |= OW_TEMP_DONE;
        while (sc->flags & OW_TEMP_RUNNING) {
                wakeup(sc);
                msleep(sc->event_thread, &sc->temp_lock, PWAIT, "owtun", 0);
        }
        mtx_destroy(&sc->temp_lock);

        return 0;
}

static device_method_t ow_temp_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         ow_temp_probe),
        DEVMETHOD(device_attach,        ow_temp_attach),
        DEVMETHOD(device_detach,        ow_temp_detach),
        DEVMETHOD_END
};

static driver_t ow_temp_driver = {
        "ow_temp",
        ow_temp_methods,
        sizeof(struct ow_temp_softc),
};

DRIVER_MODULE(ow_temp, ow, ow_temp_driver, 0, 0);
MODULE_DEPEND(ow_temp, ow, 1, 1, 1);