/* $NetBSD: mkclock_isa.c,v 1.15 2014/11/20 16:34:25 christos Exp $ */

/* $NetBSD: mkclock_isa.c,v 1.15 2014/11/20 16:34:25 christos Exp $ */

/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Klaus J. Klein.
*
* 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.
*/

/*
* Mostek MK48T18 time-of-day chip attachment to ISA bus, using two
* 8-bit ports for address selection and one 8-bit port for data.
*/

#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
__KERNEL_RCSID(0, "$NetBSD: mkclock_isa.c,v 1.15 2014/11/20 16:34:25 christos Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <sys/bus.h>

#include <dev/clock_subr.h>
#include <dev/ic/mk48txxreg.h>
#include <dev/ic/mk48txxvar.h>

#include <dev/isa/isavar.h>

/* Offsets of registers into ISA I/O space */
#define MKCLOCK_STB0 0 /* Address low */
#define MKCLOCK_STB1 1 /* Address high */
#define MKCLOCK_DATA 3 /* Data port */

#define MKCLOCK_NPORTS (MKCLOCK_DATA - MKCLOCK_STB0 + 1)

/* Autoconfiguration interface */
int mkclock_isa_match(device_t, cfdata_t, void *);
void mkclock_isa_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(mkclock_isa, sizeof(struct mk48txx_softc),
mkclock_isa_match, mkclock_isa_attach, NULL, NULL);

/* mk48txx interface */
uint8_t mkclock_isa_nvrd(struct mk48txx_softc *, int);
void mkclock_isa_nvwr(struct mk48txx_softc *, int, uint8_t);

int
mkclock_isa_match(device_t parent, cfdata_t cf, void *aux)
{
struct isa_attach_args *ia = aux;
struct mk48txx_softc mk48txx, *sc;
uint8_t csr, ocsr;
unsigned int t1, t2;
int found;

found = 0;

if (ia->ia_nio < 1 ||
(ia->ia_io[0].ir_addr != ISA_UNKNOWN_PORT &&
ia->ia_io[0].ir_addr != 0x74))
return (0);

if (ia->ia_niomem > 0 &&
(ia->ia_iomem[0].ir_addr != ISA_UNKNOWN_IOMEM))
return (0);

if (ia->ia_nirq > 0 &&
(ia->ia_irq[0].ir_irq != ISA_UNKNOWN_IRQ))
return (0);

if (ia->ia_ndrq > 0 &&
(ia->ia_drq[0].ir_drq != ISA_UNKNOWN_DRQ))
return (0);

/*
* Map I/O space, then try to determine if it's really there.
*/
sc = &mk48txx;
sc->sc_bst = ia->ia_iot;
if (bus_space_map(sc->sc_bst, 0x74, MKCLOCK_NPORTS, 0, &sc->sc_bsh))
return (0);

/* Supposedly no control bits are set after POST; check for this. */
ocsr = mkclock_isa_nvrd(sc, MK48T18_CLKOFF + MK48TXX_ICSR);
if (ocsr != 0)
goto unmap;

/* Set clock data to read mode, prohibiting updates from clock. */
csr = ocsr | MK48TXX_CSR_READ;
mkclock_isa_nvwr(sc, MK48T18_CLKOFF + MK48TXX_ICSR, csr);
/* Compare. */
if (mkclock_isa_nvrd(sc, MK48T18_CLKOFF + MK48TXX_ICSR) != csr)
goto restore;

/* Read from the seconds counter. */
t1 = bcdtobin(mkclock_isa_nvrd(sc, MK48T18_CLKOFF + MK48TXX_ISEC));
if (t1 > 59)
goto restore;

/* Make it tick again, wait, then look again. */
mkclock_isa_nvwr(sc, MK48T18_CLKOFF + MK48TXX_ICSR, ocsr);
DELAY(1100000);
mkclock_isa_nvwr(sc, MK48T18_CLKOFF + MK48TXX_ICSR, csr);
t2 = bcdtobin(mkclock_isa_nvrd(sc, MK48T18_CLKOFF + MK48TXX_ISEC));
if (t2 > 59)
goto restore;

/* If [1,2) seconds have passed since, call it a clock. */
if ((t1 + 1) % 60 == t2 || (t1 + 2) % 60 == t2)
found = 1;

restore:
mkclock_isa_nvwr(sc, MK48T18_CLKOFF + MK48TXX_ICSR, ocsr);
unmap:
bus_space_unmap(sc->sc_bst, sc->sc_bsh, MKCLOCK_NPORTS);

if (found) {
ia->ia_nio = 1;
ia->ia_io[0].ir_addr = 0x74;
ia->ia_io[0].ir_size = MKCLOCK_NPORTS;

ia->ia_niomem = 0;
ia->ia_nirq = 0;
ia->ia_ndrq = 0;
}

return (found);
}

void
mkclock_isa_attach(device_t parent, device_t self, void *aux)
{
struct mk48txx_softc *sc = device_private(self);
struct isa_attach_args *ia = aux;

sc->sc_dev = self;

/* Map I/O space. */
sc->sc_bst = ia->ia_iot;
if (bus_space_map(sc->sc_bst, ia->ia_io[0].ir_addr,
ia->ia_io[0].ir_size, 0, &sc->sc_bsh))
panic("mkclock_isa_attach: couldn't map clock I/O space");

/* Attach to MI mk48txx driver. */
sc->sc_model = "mk48t18";
sc->sc_year0 = 1968;
sc->sc_nvrd = mkclock_isa_nvrd;
sc->sc_nvwr = mkclock_isa_nvwr;

mk48txx_attach(sc);

aprint_normal(" Timekeeper NVRAM/RTC\n");
}

/*
* Bus access methods for MI mk48txx driver.
*/
uint8_t
mkclock_isa_nvrd(struct mk48txx_softc *sc, int off)
{
bus_space_tag_t iot;
bus_space_handle_t ioh;
uint8_t datum;
int s;

iot = sc->sc_bst;
ioh = sc->sc_bsh;

s = splclock();
bus_space_write_1(iot, ioh, MKCLOCK_STB0, off & 0xff);
bus_space_write_1(iot, ioh, MKCLOCK_STB1, off >> 8);
datum = bus_space_read_1(iot, ioh, MKCLOCK_DATA);
splx(s);

return (datum);
}

void
mkclock_isa_nvwr(struct mk48txx_softc *sc, int off, uint8_t datum)
{
bus_space_tag_t iot;
bus_space_handle_t ioh;
int s;

iot = sc->sc_bst;
ioh = sc->sc_bsh;

s = splclock();
bus_space_write_1(iot, ioh, MKCLOCK_STB0, off & 0xff);
bus_space_write_1(iot, ioh, MKCLOCK_STB1, off >> 8);
bus_space_write_1(iot, ioh, MKCLOCK_DATA, datum);
splx(s);
}