/*
 * Copyright (c) 2000 Sascha Schumann. 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 SASCHA SCHUMANN ``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 REGENTS 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: src/sys/dev/ppbus/pcfclock.c,v 1.3.2.1 2000/05/24 00:20:57 n_hibma Exp $
 *
 */

#include "opt_pcfclock.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/uio.h>

#include <machine/clock.h>      /* for DELAY */

#include <bus/ppbus/ppbconf.h>
#include <bus/ppbus/ppb_msq.h>
#include <bus/ppbus/ppbio.h>

#include "ppbus_if.h"

#define PCFCLOCK_NAME "pcfclock"

struct pcfclock_data {
        int     count;
        struct  ppb_device pcfclock_dev;
};

#define DEVTOSOFTC(dev) \
        ((struct pcfclock_data *)device_get_softc(dev))
#define UNITOSOFTC(unit) \
        ((struct pcfclock_data *)devclass_get_softc(pcfclock_devclass, (unit)))
#define UNITODEVICE(unit) \
        (devclass_get_device(pcfclock_devclass, (unit)))

static devclass_t pcfclock_devclass;

static  d_open_t                pcfclock_open;
static  d_close_t               pcfclock_close;
static  d_read_t                pcfclock_read;

static struct dev_ops pcfclock_ops = {
        { PCFCLOCK_NAME, 0, 0 },
        .d_open =       pcfclock_open,
        .d_close =      pcfclock_close,
        .d_read =       pcfclock_read,
};

#ifndef PCFCLOCK_MAX_RETRIES
#define PCFCLOCK_MAX_RETRIES 10
#endif

#define AFC_HI 0
#define AFC_LO AUTOFEED

/* AUTO FEED is used as clock */
#define AUTOFEED_CLOCK(val) \
        ctr = (ctr & ~(AUTOFEED)) ^ (val); ppb_wctr(ppbus, ctr)

/* SLCT is used as clock */
#define CLOCK_OK \
        ((ppb_rstr(ppbus) & SELECT) == (i & 1 ? SELECT : 0))

/* PE is used as data */
#define BIT_SET (ppb_rstr(ppbus)&PERROR)

/* the first byte sent as reply must be 00001001b */
#define PCFCLOCK_CORRECT_SYNC(buf) (buf[0] == 9)

#define NR(buf, off) (buf[off+1]*10+buf[off])

/* check for correct input values */
#define PCFCLOCK_CORRECT_FORMAT(buf) (\
        NR(buf, 14) <= 99 && \
        NR(buf, 12) <= 12 && \
        NR(buf, 10) <= 31 && \
        NR(buf,  6) <= 23 && \
        NR(buf,  4) <= 59 && \
        NR(buf,  2) <= 59)

#define PCFCLOCK_BATTERY_STATUS_LOW(buf) (buf[8] & 4)
         
#define PCFCLOCK_CMD_TIME 0             /* send current time */
#define PCFCLOCK_CMD_COPY 7     /* copy received signal to PC */

static int
pcfclock_probe(device_t dev)
{
        struct pcfclock_data *sc;

        device_set_desc(dev, "PCF-1.0");

        sc = DEVTOSOFTC(dev);
        bzero(sc, sizeof(struct pcfclock_data));
        
        return (0);
}

static int
pcfclock_attach(device_t dev)
{
        int unit;
        
        unit = device_get_unit(dev);

        make_dev(&pcfclock_ops, unit,
                 UID_ROOT, GID_WHEEL, 0444, PCFCLOCK_NAME "%d", unit);

        return (0);
}

static int 
pcfclock_open(struct dev_open_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        u_int unit = minor(dev);
        struct pcfclock_data *sc = UNITOSOFTC(unit);
        device_t pcfclockdev = UNITODEVICE(unit);
        device_t ppbus = device_get_parent(pcfclockdev);
        int res;
        
        if (!sc)
                return (ENXIO);

        if ((res = ppb_request_bus(ppbus, pcfclockdev,
                (ap->a_oflags & O_NONBLOCK) ? PPB_DONTWAIT : PPB_WAIT)))
                return (res);

        sc->count++;
        
        return (0);
}

static int
pcfclock_close(struct dev_close_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        u_int unit = minor(dev);
        struct pcfclock_data *sc = UNITOSOFTC(unit);
        device_t pcfclockdev = UNITODEVICE(unit);
        device_t ppbus = device_get_parent(pcfclockdev);

        sc->count--;
        if (sc->count == 0) {
                ppb_release_bus(ppbus, pcfclockdev);
        }

        return (0);
}

static void
pcfclock_write_cmd(cdev_t dev, unsigned char command)
{
        u_int unit = minor(dev);
        device_t ppidev = UNITODEVICE(unit);
        device_t ppbus = device_get_parent(ppidev);
        unsigned char ctr = 14;
        char i;
        
        for (i = 0; i <= 7; i++) {
                ppb_wdtr(ppbus, i);
                AUTOFEED_CLOCK(i & 1 ? AFC_HI : AFC_LO);
                DELAY(3000);
        }
        ppb_wdtr(ppbus, command);
        AUTOFEED_CLOCK(AFC_LO);
        DELAY(3000);
        AUTOFEED_CLOCK(AFC_HI);
}

static void
pcfclock_display_data(cdev_t dev, char buf[18]) 
{
        u_int unit = minor(dev);
#ifdef PCFCLOCK_VERBOSE
        int year;

        year = NR(buf, 14);
        if (year < 70)
                year += 100;
        kprintf(PCFCLOCK_NAME "%d: %02d.%02d.%4d %02d:%02d:%02d, "
                        "battery status: %s\n",
                        unit,
                        NR(buf, 10), NR(buf, 12), 1900 + year,
                        NR(buf, 6), NR(buf, 4), NR(buf, 2),
                        PCFCLOCK_BATTERY_STATUS_LOW(buf) ? "LOW" : "ok");
#else
        if (PCFCLOCK_BATTERY_STATUS_LOW(buf))
                kprintf(PCFCLOCK_NAME "%d: BATTERY STATUS LOW ON\n",
                                unit);
#endif
}

static int 
pcfclock_read_data(cdev_t dev, char *buf, ssize_t bits)
{
        u_int unit = minor(dev);
        device_t ppidev = UNITODEVICE(unit);
        device_t ppbus = device_get_parent(ppidev);
        int i;
        char waitfor;
        int offset;

        /* one byte per four bits */
        bzero(buf, ((bits + 3) >> 2) + 1);
        
        waitfor = 100;
        for (i = 0; i <= bits; i++) {
                /* wait for clock, maximum (waitfor*100) usec */
                while(!CLOCK_OK && --waitfor > 0)
                        DELAY(100);

                /* timed out? */
                if (!waitfor) 
                        return (EIO);
                
                waitfor = 100; /* reload */
                
                /* give it some time */
                DELAY(500);

                /* calculate offset into buffer */
                offset = i >> 2;
                buf[offset] <<= 1;

                if (BIT_SET)
                        buf[offset] |= 1;
        }

        return (0);
}

static int 
pcfclock_read_dev(cdev_t dev, char *buf, int maxretries) 
{
        u_int unit = minor(dev);
        device_t ppidev = UNITODEVICE(unit);
        device_t ppbus = device_get_parent(ppidev);
        int error = 0;

        ppb_set_mode(ppbus, PPB_COMPATIBLE);

        while (--maxretries > 0) {
                pcfclock_write_cmd(dev, PCFCLOCK_CMD_TIME);
                if (pcfclock_read_data(dev, buf, 68))
                        continue;
                        
                if (!PCFCLOCK_CORRECT_SYNC(buf))
                        continue;

                if (!PCFCLOCK_CORRECT_FORMAT(buf))
                        continue;

                break;
        }

        if (!maxretries)
                error = EIO;
        
        return (error);
}

static int
pcfclock_read(struct dev_read_args *ap)
{
        cdev_t dev = ap->a_head.a_dev;
        u_int unit = minor(dev);
        char buf[18];
        int error = 0;

        if (ap->a_uio->uio_resid < 18)
                return (ERANGE);

        error = pcfclock_read_dev(dev, buf, PCFCLOCK_MAX_RETRIES);
        
        if (error) {
                kprintf(PCFCLOCK_NAME "%d: no PCF found\n", unit);
        } else {
                pcfclock_display_data(dev, buf);
                
                uiomove(buf, 18, ap->a_uio);
        }
        
        return (error);
}

/*
 * Because pcfclock is a static device that always exists under any
 * attached ppbus, and not scanned by the ppbus, we need an identify function
 * to create the device.
 */
static device_method_t pcfclock_methods[] = {
        /* device interface */
        DEVMETHOD(device_identify,      bus_generic_identify),
        DEVMETHOD(device_probe,         pcfclock_probe),
        DEVMETHOD(device_attach,        pcfclock_attach),

        DEVMETHOD_END
};

static driver_t pcfclock_driver = {
        PCFCLOCK_NAME,
        pcfclock_methods,
        sizeof(struct pcfclock_data),
};

DRIVER_MODULE(pcfclock, ppbus, pcfclock_driver, pcfclock_devclass, NULL, NULL);