freebsd-skq/sys/dev/mc146818/mc146818.c
marius 3cd1a80422 Add a driver back end for MC146818 and compatible clocks based on the
respective NetBSD driver for use with the genclock interface.
It's first use will be on sparc64 but it was also tested on alpha with
a preliminary patch to switch alpha to use the genclock code together
with this driver instead of the respective code in alpha/alpha/clock.c
and the rather MD mcclock(4). Using it on i386 and amd64 won't be that
hard but some changes/extensions to improve the genclock code in general
should be done first, e.g. add locking and make it easier to access the
NVRAM usually coupled with RTCs.
2004-11-17 16:37:25 +00:00

276 lines
7.2 KiB
C

/*
* Copyright (c) 2003 Izumi Tsutsui. 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.
*
* from: NetBSD: mc146818.c,v 1.4 2003/11/24 06:20:40 tsutsui Exp
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* mc146818 and compatible time of day chip subroutines
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <machine/bus.h>
#include <dev/mc146818/mc146818reg.h>
#include <dev/mc146818/mc146818var.h>
#include "clock_if.h"
static u_int mc146818_def_getcent(device_t);
static void mc146818_def_setcent(device_t, u_int);
static u_int mc146818_def_read(device_t, u_int);
static void mc146818_def_write(device_t, u_int, u_int);
int
mc146818_attach(device_t dev)
{
struct mc146818_softc *sc;
sc = device_get_softc(dev);
if (sc->sc_mcread == NULL)
sc->sc_mcread = mc146818_def_read;
if (sc->sc_mcwrite == NULL)
sc->sc_mcwrite = mc146818_def_write;
if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
/*
* Note that setting MC146818_NO_CENT_ADJUST means that
* the century has to be stored in NVRAM somewhere.
*/
if (sc->sc_getcent == NULL)
sc->sc_getcent = mc146818_def_getcent;
if (sc->sc_setcent == NULL)
sc->sc_setcent = mc146818_def_setcent;
}
if (!(*sc->sc_mcread)(dev, MC_REGD) & MC_REGD_VRT) {
device_printf(dev, "mc146818_attach: battery low\n");
return (ENXIO);
}
sc->sc_rega = MC_BASE_32_KHz;
(*sc->sc_mcwrite)(dev, MC_REGA, sc->sc_rega);
sc->sc_regb = 0;
sc->sc_regb |= (sc->sc_flag & MC146818_BCD) ? 0 : MC_REGB_BINARY;
sc->sc_regb |= (sc->sc_flag & MC146818_12HR) ? 0 : MC_REGB_24HR;
(*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
clock_register(dev, 1000000); /* 1 second resolution. */
return (0);
}
/*
* Get time of day and convert it to a struct timespec.
* Return 0 on success, an error number otherwise.
*/
int
mc146818_gettime(device_t dev, struct timespec *ts)
{
struct mc146818_softc *sc;
struct clocktime ct;
int timeout, cent, year;
sc = device_get_softc(dev);
timeout = 1000000; /* XXX how long should we wait? */
/*
* XXX: Use a spinlock to mutex register access and increase the
* likelihood that all registers are read before an update
* occurs.
*/
/*
* If MC_REGA_UIP is 0 we have at least 244us before the next
* update. If it's 1 an update is imminent.
*/
for (;;) {
if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP))
break;
if (--timeout < 0) {
device_printf(dev, "mc146818_gettime: timeout\n");
return (EBUSY);
}
}
#define FROMREG(x) ((sc->sc_flag & MC146818_BCD) ? FROMBCD(x) : (x))
ct.nsec = 0;
ct.sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
ct.min = FROMREG((*sc->sc_mcread)(dev, MC_MIN));
ct.hour = FROMREG((*sc->sc_mcread)(dev, MC_HOUR));
ct.dow = FROMREG((*sc->sc_mcread)(dev, MC_DOW)) - 1;
ct.day = FROMREG((*sc->sc_mcread)(dev, MC_DOM));
ct.mon = FROMREG((*sc->sc_mcread)(dev, MC_MONTH));
year = FROMREG((*sc->sc_mcread)(dev, MC_YEAR));
if (sc->sc_getcent) {
cent = (*sc->sc_getcent)(dev);
year += cent * 100;
}
year += sc->sc_year0;
if (year < POSIX_BASE_YEAR && !(sc->sc_flag & MC146818_NO_CENT_ADJUST))
year += 100;
ct.year = year;
return (clock_ct_to_ts(&ct, ts));
}
#ifdef notyet
int
mc146818_getsecs(device_t dev, int *secp)
{
struct mc146818_softc *sc;
int sec, timeout;
sc = device_get_softc(dev);
timeout = 1000000; /* XXX how long should we wait? */
for (;;) {
if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP)) {
sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
break;
}
if (--timeout == 0) {
device_printf(dev, "mc146818_getsecs: timeout\n");
return (EBUSY);
}
}
#undef FROMREG
*secp = sec;
return (0);
}
#endif
/*
* Set the time of day clock based on the value of the struct timespec arg.
* Return 0 on success, an error number otherwise.
*/
int
mc146818_settime(device_t dev, struct timespec *ts)
{
struct mc146818_softc *sc;
struct clocktime ct;
int cent, year;
sc = device_get_softc(dev);
/* Accuracy is only one second. */
if (ts->tv_nsec >= 500000000)
ts->tv_sec++;
ts->tv_nsec = 0;
clock_ts_to_ct(ts, &ct);
/* Disable RTC updates and interrupts (if enabled). */
(*sc->sc_mcwrite)(dev, MC_REGB,
((sc->sc_regb & (MC_REGB_BINARY | MC_REGB_24HR)) | MC_REGB_SET));
#define TOREG(x) ((sc->sc_flag & MC146818_BCD) ? TOBCD(x) : (x))
(*sc->sc_mcwrite)(dev, MC_SEC, TOREG(ct.sec));
(*sc->sc_mcwrite)(dev, MC_MIN, TOREG(ct.min));
(*sc->sc_mcwrite)(dev, MC_HOUR, TOREG(ct.hour));
(*sc->sc_mcwrite)(dev, MC_DOW, TOREG(ct.dow + 1));
(*sc->sc_mcwrite)(dev, MC_DOM, TOREG(ct.day));
(*sc->sc_mcwrite)(dev, MC_MONTH, TOREG(ct.mon));
year = ct.year - sc->sc_year0;
if (sc->sc_setcent) {
cent = year / 100;
(*sc->sc_setcent)(dev, cent);
year -= cent * 100;
}
if (year > 99 && (sc->sc_flag & MC146818_NO_CENT_ADJUST) == 0)
year -= 100;
(*sc->sc_mcwrite)(dev, MC_YEAR, TOREG(year));
/* Reenable RTC updates and interrupts. */
(*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
#undef TOREG
return (0);
}
#define MC_ADDR 0
#define MC_DATA 1
static u_int
mc146818_def_read(device_t dev, u_int reg)
{
struct mc146818_softc *sc;
sc = device_get_softc(dev);
bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
return (bus_space_read_1(sc->sc_bst, sc->sc_bsh, MC_DATA));
}
static void
mc146818_def_write(device_t dev, u_int reg, u_int val)
{
struct mc146818_softc *sc;
sc = device_get_softc(dev);
bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_DATA, val);
}
/*
* Looks like it's common even across platforms to store the century at
* 0x32 in the NVRAM of the mc146818.
*/
#define MC_CENT 0x32
static u_int
mc146818_def_getcent(device_t dev)
{
struct mc146818_softc *sc;
sc = device_get_softc(dev);
return ((*sc->sc_mcread)(dev, MC_CENT));
}
static void
mc146818_def_setcent(device_t dev, u_int cent)
{
struct mc146818_softc *sc;
sc = device_get_softc(dev);
(*sc->sc_mcwrite)(dev, MC_CENT, cent);
}