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/*-
* Copyright (c) 2017 Andrew Turner
* All rights reserved.
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
* ("CTSRD"), as part of the DARPA CRASH research programme.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/efi.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include "clock_if.h"
static bool efirtc_zeroes_subseconds;
static struct timespec efirtc_resadj;
static const u_int us_per_s = 1000000;
static const u_int ns_per_s = 1000000000;
static const u_int ns_per_us = 1000;
static void
efirtc_identify(driver_t *driver, device_t parent)
{
/* Don't add the driver unless we have working runtime services. */
if (efi_rt_ok() != 0)
return;
if (device_find_child(parent, "efirtc", -1) != NULL)
return;
if (BUS_ADD_CHILD(parent, 0, "efirtc", -1) == NULL)
device_printf(parent, "add child failed\n");
}
static int
efirtc_probe(device_t dev)
{
struct efi_tm tm;
int error;
/*
* Check whether we can read the time. This will stop us from attaching
* when there is EFI Runtime support but the gettime function is
* unimplemented, e.g. on some builds of U-Boot.
*/
if ((error = efi_get_time(&tm)) != 0) {
if (bootverbose)
device_printf(dev, "cannot read EFI realtime clock\n");
return (error);
}
device_set_desc(dev, "EFI Realtime Clock");
return (BUS_PROBE_DEFAULT);
}
static int
efirtc_attach(device_t dev)
{
struct efi_tmcap tmcap;
long res;
int error;
bzero(&tmcap, sizeof(tmcap));
if ((error = efi_get_time_capabilities(&tmcap)) != 0) {
device_printf(dev, "cannot get EFI time capabilities");
return (error);
}
/* Translate resolution in Hz to tick length in usec. */
if (tmcap.tc_res == 0)
res = us_per_s; /* 0 is insane, assume 1 Hz. */
else if (tmcap.tc_res > us_per_s)
res = 1; /* 1us is the best we can represent */
else
res = us_per_s / tmcap.tc_res;
/* Clock rounding adjustment is 1/2 of resolution, in nsec. */
efirtc_resadj.tv_nsec = (res * ns_per_us) / 2;
/* Does the clock zero the subseconds when time is set? */
efirtc_zeroes_subseconds = tmcap.tc_stz;
/*
* Register. If the clock zeroes out the subseconds when it's set,
* schedule the SetTime calls to happen just before top-of-second.
*/
clock_register_flags(dev, res, CLOCKF_SETTIME_NO_ADJ);
if (efirtc_zeroes_subseconds)
clock_schedule(dev, ns_per_s - ns_per_us);
return (0);
}
static int
efirtc_detach(device_t dev)
{
clock_unregister(dev);
return (0);
}
static int
efirtc_gettime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
struct efi_tm tm;
int error;
error = efi_get_time(&tm);
if (error != 0)
return (error);
ct.sec = tm.tm_sec;
ct.min = tm.tm_min;
ct.hour = tm.tm_hour;
ct.day = tm.tm_mday;
ct.mon = tm.tm_mon;
ct.year = tm.tm_year;
ct.nsec = tm.tm_nsec;
clock_dbgprint_ct(dev, CLOCK_DBG_READ, &ct);
return (clock_ct_to_ts(&ct, ts));
}
static int
efirtc_settime(device_t dev, struct timespec *ts)
{
struct clocktime ct;
struct efi_tm tm;
/*
* We request a timespec with no resolution-adjustment so that we can
* apply it ourselves based on whether or not the clock zeroes the
* sub-second part of the time when setting the time.
*/
ts->tv_sec -= utc_offset();
if (!efirtc_zeroes_subseconds)
timespecadd(ts, &efirtc_resadj);
clock_ts_to_ct(ts, &ct);
clock_dbgprint_ct(dev, CLOCK_DBG_WRITE, &ct);
bzero(&tm, sizeof(tm));
tm.tm_sec = ct.sec;
tm.tm_min = ct.min;
tm.tm_hour = ct.hour;
tm.tm_mday = ct.day;
tm.tm_mon = ct.mon;
tm.tm_year = ct.year;
tm.tm_nsec = ct.nsec;
return (efi_set_time(&tm));
}
static device_method_t efirtc_methods[] = {
/* Device interface */
DEVMETHOD(device_identify, efirtc_identify),
DEVMETHOD(device_probe, efirtc_probe),
DEVMETHOD(device_attach, efirtc_attach),
DEVMETHOD(device_detach, efirtc_detach),
/* Clock interface */
DEVMETHOD(clock_gettime, efirtc_gettime),
DEVMETHOD(clock_settime, efirtc_settime),
DEVMETHOD_END
};
static devclass_t efirtc_devclass;
static driver_t efirtc_driver = {
"efirtc",
efirtc_methods,
0
};
DRIVER_MODULE(efirtc, nexus, efirtc_driver, efirtc_devclass, 0, 0);
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