/*      $NetBSD: wdog.c,v 1.20 2025/01/27 21:20:25 andvar Exp $ */

/*-
* Copyright (C) 2000 SAITOH Masanobu.  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.
* 3. The name of the author may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: wdog.c,v 1.20 2025/01/27 21:20:25 andvar Exp $");

#include <sys/param.h>
#include <sys/buf.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/uio.h>
#include <sys/device.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/proc.h>
#include <sys/syslog.h>
#include <sys/conf.h>

#include <machine/cpu.h>
#include <machine/intr.h>

#include <sh3/frame.h>
#include <sh3/wdtreg.h>
#include <sh3/wdogvar.h>
#include <sh3/exception.h>

struct wdog_softc {
       device_t sc_dev;
       int flags;
};

static int wdogmatch(device_t, cfdata_t, void *);
static void wdogattach(device_t, device_t, void *);
static int wdogintr(void *);

CFATTACH_DECL_NEW(wdog, sizeof(struct wdog_softc),
   wdogmatch, wdogattach, NULL, NULL);

extern struct cfdriver wdog_cd;

dev_type_open(wdogopen);
dev_type_close(wdogclose);
dev_type_ioctl(wdogioctl);

const struct cdevsw wdog_cdevsw = {
       .d_open = wdogopen,
       .d_close = wdogclose,
       .d_read = noread,
       .d_write = nowrite,
       .d_ioctl = wdogioctl,
       .d_stop = nostop,
       .d_tty = notty,
       .d_poll = nopoll,
       .d_mmap = nommap,
       .d_kqfilter = nokqfilter,
       .d_discard = nodiscard,
       .d_flag = 0
};

void
wdog_wr_cnt(unsigned char x)
{

       SHREG_WTCNT_W = WTCNT_W_M | (unsigned short) x;
}

void
wdog_wr_csr(unsigned char x)
{

       SHREG_WTCSR_W = WTCSR_W_M | (unsigned short) x;
}

static int
wdogmatch(device_t parent, cfdata_t cfp, void *aux)
{

       if (strcmp(cfp->cf_name, "wdog"))
               return (0);

       return (1);
}

/*
*  functions for probing.
*/
/* ARGSUSED */
static void
wdogattach(device_t parent, device_t self, void *aux)
{
       struct wdog_softc *sc;

       sc = device_private(self);
       sc->sc_dev = self;

       aprint_naive("\n");
       aprint_normal(": internal watchdog timer\n");

       wdog_wr_csr(WTCSR_WT | WTCSR_CKS_4096); /* default to wt mode */

       intc_intr_establish(SH_INTEVT_WDT_ITI, IST_LEVEL, IPL_SOFTCLOCK,
           wdogintr, 0);
}

/*ARGSUSED*/
int
wdogopen(dev_t dev, int flag, int mode, struct lwp *l)
{
       struct wdog_softc *sc;

       sc = device_lookup_private(&wdog_cd, minor(dev));
       if (sc == NULL)
               return (ENXIO);

       if (sc->flags & WDOGF_OPEN)
               return (EBUSY);
       sc->flags |= WDOGF_OPEN;
       return (0);
}

/*ARGSUSED*/
int
wdogclose(dev_t dev, int flag, int mode, struct lwp *l)
{
       struct wdog_softc *sc;

       sc = device_lookup_private(&wdog_cd, minor(dev));

       if (sc->flags & WDOGF_OPEN)
               sc->flags = 0;

       return (0);
}

extern unsigned int maxwdog;

/*ARGSUSED*/
int
wdogioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
{
       int error = 0;
       int request;

       switch (cmd) {
       case SIOWDOGSETMODE:
               request = *(int *)data;

               switch (request) {
               case WDOGM_RESET:
                       wdog_wr_csr(SHREG_WTCSR_R | WTCSR_WT);
                       break;
               case WDOGM_INTR:
                       wdog_wr_csr(SHREG_WTCSR_R & ~WTCSR_WT);
                       break;
               default:
                       error = EINVAL;
                       break;
               }
               break;
       case SIORESETWDOG:
               wdog_wr_cnt(0);         /* reset to zero */
               break;
       case SIOSTARTWDOG:
               wdog_wr_csr(WTCSR_WT | WTCSR_CKS_4096);
               wdog_wr_cnt(0);         /* reset to zero */
               wdog_wr_csr(SHREG_WTCSR_R | WTCSR_TME); /* start!!! */
               break;
       case SIOSTOPWDOG:
               wdog_wr_csr(SHREG_WTCSR_R & ~WTCSR_TME); /* stop */
               break;
       case SIOSETWDOG:
               request = *(int *)data;

               if (request > 2) {
                       error = EINVAL;
                       break;
               }
               break;
       default:
               error = EINVAL;
               break;
       }

       return (error);
}

int
wdogintr(void *arg)
{
       struct trapframe *frame = arg;

       wdog_wr_csr(SHREG_WTCSR_R & ~WTCSR_IOVF); /* clear overflow bit */
       wdog_wr_cnt(0);                 /* reset to zero */
       printf("wdog trapped: spc = %x\n", frame->tf_spc);

       return (0);
}