freebsd-dev/sys/x86/isa/atrtc.c
Andriy Gapon 2b89f1fc9e atrtc: remove (pre-)historic check of RTC NVRAM at address 0x0e
Old scrolls tell that once upon a time IBM AT BIOS was known to put some
useful system diagnostic information into RTC NVRAM.  It is not really
known if and for how long PC BIOSes followed that convention, but I
believe that many, if not all, modern BIOSes do not do that any more
(not mentioning other types of x86 firmware).
Some diagnostic bits don't even make any sense any longer.
The check results in confusing messages upon boot on some systems.
So I am removing it.

Discussed with:	bde, jhb, mav
MFC after:	3 weeks
2010-10-16 10:45:36 +00:00

404 lines
10 KiB
C

/*-
* Copyright (c) 2008 Poul-Henning Kamp
* Copyright (c) 2010 Alexander Motin <mav@FreeBSD.org>
* 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 THE AUTHOR 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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_isa.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/rman.h>
#include <sys/timeet.h>
#include <isa/rtc.h>
#ifdef DEV_ISA
#include <isa/isareg.h>
#include <isa/isavar.h>
#endif
#include <machine/intr_machdep.h>
#include "clock_if.h"
#define RTC_LOCK mtx_lock_spin(&clock_lock)
#define RTC_UNLOCK mtx_unlock_spin(&clock_lock)
int atrtcclock_disable = 0;
static int rtc_reg = -1;
static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
static u_char rtc_statusb = RTCSB_24HR;
/*
* RTC support routines
*/
int
rtcin(int reg)
{
u_char val;
RTC_LOCK;
if (rtc_reg != reg) {
inb(0x84);
outb(IO_RTC, reg);
rtc_reg = reg;
inb(0x84);
}
val = inb(IO_RTC + 1);
RTC_UNLOCK;
return (val);
}
void
writertc(int reg, u_char val)
{
RTC_LOCK;
if (rtc_reg != reg) {
inb(0x84);
outb(IO_RTC, reg);
rtc_reg = reg;
inb(0x84);
}
outb(IO_RTC + 1, val);
inb(0x84);
RTC_UNLOCK;
}
static __inline int
readrtc(int port)
{
return(bcd2bin(rtcin(port)));
}
static void
atrtc_start(void)
{
writertc(RTC_STATUSA, rtc_statusa);
writertc(RTC_STATUSB, RTCSB_24HR);
}
static void
atrtc_rate(unsigned rate)
{
rtc_statusa = RTCSA_DIVIDER | rate;
writertc(RTC_STATUSA, rtc_statusa);
}
static void
atrtc_enable_intr(void)
{
rtc_statusb |= RTCSB_PINTR;
writertc(RTC_STATUSB, rtc_statusb);
rtcin(RTC_INTR);
}
static void
atrtc_disable_intr(void)
{
rtc_statusb &= ~RTCSB_PINTR;
writertc(RTC_STATUSB, rtc_statusb);
rtcin(RTC_INTR);
}
void
atrtc_restore(void)
{
/* Restore all of the RTC's "status" (actually, control) registers. */
rtcin(RTC_STATUSA); /* dummy to get rtc_reg set */
writertc(RTC_STATUSB, RTCSB_24HR);
writertc(RTC_STATUSA, rtc_statusa);
writertc(RTC_STATUSB, rtc_statusb);
rtcin(RTC_INTR);
}
/**********************************************************************
* RTC driver for subr_rtc
*/
struct atrtc_softc {
int port_rid, intr_rid;
struct resource *port_res;
struct resource *intr_res;
void *intr_handler;
struct eventtimer et;
};
static int
rtc_start(struct eventtimer *et,
struct bintime *first, struct bintime *period)
{
atrtc_rate(max(fls((period->frac + (period->frac >> 1)) >> 32) - 17, 1));
atrtc_enable_intr();
return (0);
}
static int
rtc_stop(struct eventtimer *et)
{
atrtc_disable_intr();
return (0);
}
/*
* This routine receives statistical clock interrupts from the RTC.
* As explained above, these occur at 128 interrupts per second.
* When profiling, we receive interrupts at a rate of 1024 Hz.
*
* This does not actually add as much overhead as it sounds, because
* when the statistical clock is active, the hardclock driver no longer
* needs to keep (inaccurate) statistics on its own. This decouples
* statistics gathering from scheduling interrupts.
*
* The RTC chip requires that we read status register C (RTC_INTR)
* to acknowledge an interrupt, before it will generate the next one.
* Under high interrupt load, rtcintr() can be indefinitely delayed and
* the clock can tick immediately after the read from RTC_INTR. In this
* case, the mc146818A interrupt signal will not drop for long enough
* to register with the 8259 PIC. If an interrupt is missed, the stat
* clock will halt, considerably degrading system performance. This is
* why we use 'while' rather than a more straightforward 'if' below.
* Stat clock ticks can still be lost, causing minor loss of accuracy
* in the statistics, but the stat clock will no longer stop.
*/
static int
rtc_intr(void *arg)
{
struct atrtc_softc *sc = (struct atrtc_softc *)arg;
int flag = 0;
while (rtcin(RTC_INTR) & RTCIR_PERIOD) {
flag = 1;
if (sc->et.et_active)
sc->et.et_event_cb(&sc->et, sc->et.et_arg);
}
return(flag ? FILTER_HANDLED : FILTER_STRAY);
}
/*
* Attach to the ISA PnP descriptors for the timer and realtime clock.
*/
static struct isa_pnp_id atrtc_ids[] = {
{ 0x000bd041 /* PNP0B00 */, "AT realtime clock" },
{ 0 }
};
static int
atrtc_probe(device_t dev)
{
int result;
result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids);
/* ENOENT means no PnP-ID, device is hinted. */
if (result == ENOENT) {
device_set_desc(dev, "AT realtime clock");
return (BUS_PROBE_LOW_PRIORITY);
}
return (result);
}
static int
atrtc_attach(device_t dev)
{
struct atrtc_softc *sc;
u_long s;
int i;
sc = device_get_softc(dev);
if (!(sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT,
&sc->port_rid, IO_RTC, IO_RTC + 1, 2, RF_ACTIVE)))
device_printf(dev,"Warning: Couldn't map I/O.\n");
atrtc_start();
clock_register(dev, 1000000);
bzero(&sc->et, sizeof(struct eventtimer));
if (!atrtcclock_disable &&
(resource_int_value(device_get_name(dev), device_get_unit(dev),
"clock", &i) != 0 || i != 0)) {
sc->intr_rid = 0;
while (bus_get_resource(dev, SYS_RES_IRQ, sc->intr_rid,
&s, NULL) == 0 && s != 8)
sc->intr_rid++;
if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
&sc->intr_rid, 8, 8, 1, RF_ACTIVE))) {
device_printf(dev,"Can't map interrupt.\n");
return (0);
} else if ((bus_setup_intr(dev, sc->intr_res,
INTR_MPSAFE | INTR_TYPE_CLK,
(driver_filter_t *)rtc_intr, NULL,
sc, &sc->intr_handler))) {
device_printf(dev, "Can't setup interrupt.\n");
return (0);
} else {
/* Bind IRQ to BSP to avoid live migration. */
bus_bind_intr(dev, sc->intr_res, 0);
}
sc->et.et_name = "RTC";
sc->et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_POW2DIV;
sc->et.et_quality = 0;
sc->et.et_frequency = 32768;
sc->et.et_min_period.sec = 0;
sc->et.et_min_period.frac = 0x0008LLU << 48;
sc->et.et_max_period.sec = 0;
sc->et.et_max_period.frac = 0x8000LLU << 48;
sc->et.et_start = rtc_start;
sc->et.et_stop = rtc_stop;
sc->et.et_priv = dev;
et_register(&sc->et);
}
return(0);
}
static int
atrtc_resume(device_t dev)
{
atrtc_restore();
return(0);
}
static int
atrtc_settime(device_t dev __unused, struct timespec *ts)
{
struct clocktime ct;
clock_ts_to_ct(ts, &ct);
/* Disable RTC updates and interrupts. */
writertc(RTC_STATUSB, RTCSB_HALT | RTCSB_24HR);
writertc(RTC_SEC, bin2bcd(ct.sec)); /* Write back Seconds */
writertc(RTC_MIN, bin2bcd(ct.min)); /* Write back Minutes */
writertc(RTC_HRS, bin2bcd(ct.hour)); /* Write back Hours */
writertc(RTC_WDAY, ct.dow + 1); /* Write back Weekday */
writertc(RTC_DAY, bin2bcd(ct.day)); /* Write back Day */
writertc(RTC_MONTH, bin2bcd(ct.mon)); /* Write back Month */
writertc(RTC_YEAR, bin2bcd(ct.year % 100)); /* Write back Year */
#ifdef USE_RTC_CENTURY
writertc(RTC_CENTURY, bin2bcd(ct.year / 100)); /* ... and Century */
#endif
/* Reenable RTC updates and interrupts. */
writertc(RTC_STATUSB, rtc_statusb);
rtcin(RTC_INTR);
return (0);
}
static int
atrtc_gettime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
int s;
/* Look if we have a RTC present and the time is valid */
if (!(rtcin(RTC_STATUSD) & RTCSD_PWR)) {
device_printf(dev, "WARNING: Battery failure indication\n");
return (EINVAL);
}
/* wait for time update to complete */
/* If RTCSA_TUP is zero, we have at least 244us before next update */
s = splhigh();
while (rtcin(RTC_STATUSA) & RTCSA_TUP) {
splx(s);
s = splhigh();
}
ct.nsec = 0;
ct.sec = readrtc(RTC_SEC);
ct.min = readrtc(RTC_MIN);
ct.hour = readrtc(RTC_HRS);
ct.day = readrtc(RTC_DAY);
ct.dow = readrtc(RTC_WDAY) - 1;
ct.mon = readrtc(RTC_MONTH);
ct.year = readrtc(RTC_YEAR);
#ifdef USE_RTC_CENTURY
ct.year += readrtc(RTC_CENTURY) * 100;
#else
ct.year += 2000;
#endif
/* Set dow = -1 because some clocks don't set it correctly. */
ct.dow = -1;
return (clock_ct_to_ts(&ct, ts));
}
static device_method_t atrtc_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, atrtc_probe),
DEVMETHOD(device_attach, atrtc_attach),
DEVMETHOD(device_detach, bus_generic_detach),
DEVMETHOD(device_shutdown, bus_generic_shutdown),
DEVMETHOD(device_suspend, bus_generic_suspend),
/* XXX stop statclock? */
DEVMETHOD(device_resume, atrtc_resume),
/* clock interface */
DEVMETHOD(clock_gettime, atrtc_gettime),
DEVMETHOD(clock_settime, atrtc_settime),
{ 0, 0 }
};
static driver_t atrtc_driver = {
"atrtc",
atrtc_methods,
sizeof(struct atrtc_softc),
};
static devclass_t atrtc_devclass;
DRIVER_MODULE(atrtc, isa, atrtc_driver, atrtc_devclass, 0, 0);
DRIVER_MODULE(atrtc, acpi, atrtc_driver, atrtc_devclass, 0, 0);
#include "opt_ddb.h"
#ifdef DDB
#include <ddb/ddb.h>
DB_SHOW_COMMAND(rtc, rtc)
{
printf("%02x/%02x/%02x %02x:%02x:%02x, A = %02x, B = %02x, C = %02x\n",
rtcin(RTC_YEAR), rtcin(RTC_MONTH), rtcin(RTC_DAY),
rtcin(RTC_HRS), rtcin(RTC_MIN), rtcin(RTC_SEC),
rtcin(RTC_STATUSA), rtcin(RTC_STATUSB), rtcin(RTC_INTR));
}
#endif /* DDB */