freebsd-dev/sys/x86/isa/atrtc.c
Ian Lepore c82d887d47 Stop calling atrtc_set() from the xen timer clock_settime() method. That
removes the only reference to atrtc_set() from outside of atrtc.c, so make
it static.

The xen timer driver registers as a realtime clock with 1us resolution.  In
the past that resulted in only the xen timer's clock_settime() getting
called, so it would call atrtc_set() to set the hardware clock as well.  As
of r32090, the clock_settime() method of all registered realtime clocks gets
called, so the xen driver no longer needs to chain-call the lower-resolution
driver.

Thanks to royger@ for talking me through the xen stuff, and for testing.
2017-08-11 19:02:11 +00:00

431 lines
11 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/kdb.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"
/*
* clock_lock protects low-level access to individual hardware registers.
* atrtc_time_lock protects the entire sequence of accessing multiple registers
* to read or write the date and time.
*/
#define RTC_LOCK do { if (!kdb_active) mtx_lock_spin(&clock_lock); } while (0)
#define RTC_UNLOCK do { if (!kdb_active) mtx_unlock_spin(&clock_lock); } while (0)
struct mtx atrtc_time_lock;
MTX_SYSINIT(atrtc_lock_init, &atrtc_time_lock, "atrtc", MTX_DEF);
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)
{
int readval;
readval = rtcin(port);
if (readval >= 0 && (readval & 0xf) < 0xa && (readval & 0xf0) < 0xa0)
return (bcd2bin(readval));
return (0);
}
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);
}
static void
atrtc_set(struct timespec *ts)
{
struct clocktime ct;
clock_ts_to_ct(ts, &ct);
mtx_lock(&atrtc_time_lock);
/* 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
/* Re-enable RTC updates and interrupts. */
writertc(RTC_STATUSB, rtc_statusb);
rtcin(RTC_INTR);
mtx_unlock(&atrtc_time_lock);
}
/**********************************************************************
* 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, sbintime_t first, sbintime_t period)
{
atrtc_rate(max(fls(period + (period >> 1)) - 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;
rman_res_t s;
int i;
sc = device_get_softc(dev);
sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->port_rid,
IO_RTC, IO_RTC + 1, 2, RF_ACTIVE);
if (sc->port_res == NULL)
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++;
sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
&sc->intr_rid, 8, 8, 1, RF_ACTIVE);
if (sc->intr_res == NULL) {
device_printf(dev, "Can't map interrupt.\n");
return (0);
} else if ((bus_setup_intr(dev, sc->intr_res, INTR_TYPE_CLK,
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 = 0x00080000;
sc->et.et_max_period = 0x80000000;
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)
{
atrtc_set(ts);
return (0);
}
static int
atrtc_gettime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
/* 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.
* This is fast enough on most hardware, but a refinement would be
* to make sure that no more than 240us pass after we start reading,
* and try again if so.
*/
mtx_lock(&atrtc_time_lock);
while (rtcin(RTC_STATUSA) & RTCSA_TUP)
continue;
critical_enter();
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 += (ct.year < 80 ? 2000 : 1900);
#endif
critical_exit();
mtx_unlock(&atrtc_time_lock);
/* 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 */