205 lines
5.5 KiB
C
205 lines
5.5 KiB
C
/*-
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* Copyright (c) 2017 Andrew Turner
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* All rights reserved.
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*
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* This software was developed by SRI International and the University of
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* Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
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* ("CTSRD"), as part of the DARPA CRASH research programme.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/clock.h>
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#include <sys/efi.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include "clock_if.h"
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static bool efirtc_zeroes_subseconds;
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static struct timespec efirtc_resadj;
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static const u_int us_per_s = 1000000;
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static const u_int ns_per_s = 1000000000;
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static const u_int ns_per_us = 1000;
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static void
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efirtc_identify(driver_t *driver, device_t parent)
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{
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/* Don't add the driver unless we have working runtime services. */
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if (efi_rt_ok() != 0)
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return;
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if (device_find_child(parent, "efirtc", -1) != NULL)
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return;
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if (BUS_ADD_CHILD(parent, 0, "efirtc", -1) == NULL)
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device_printf(parent, "add child failed\n");
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}
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static int
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efirtc_probe(device_t dev)
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{
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struct efi_tm tm;
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int error;
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/*
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* Check whether we can read the time. This will stop us from attaching
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* when there is EFI Runtime support but the gettime function is
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* unimplemented, e.g. on some builds of U-Boot.
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*/
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if ((error = efi_get_time(&tm)) != 0) {
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if (bootverbose)
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device_printf(dev, "cannot read EFI realtime clock, "
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"error %d\n", error);
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return (error);
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}
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device_set_desc(dev, "EFI Realtime Clock");
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return (BUS_PROBE_DEFAULT);
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}
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static int
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efirtc_attach(device_t dev)
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{
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struct efi_tmcap tmcap;
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long res;
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int error;
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bzero(&tmcap, sizeof(tmcap));
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if ((error = efi_get_time_capabilities(&tmcap)) != 0) {
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device_printf(dev, "cannot get EFI time capabilities");
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return (error);
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}
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/* Translate resolution in Hz to tick length in usec. */
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if (tmcap.tc_res == 0)
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res = us_per_s; /* 0 is insane, assume 1 Hz. */
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else if (tmcap.tc_res > us_per_s)
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res = 1; /* 1us is the best we can represent */
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else
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res = us_per_s / tmcap.tc_res;
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/* Clock rounding adjustment is 1/2 of resolution, in nsec. */
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efirtc_resadj.tv_nsec = (res * ns_per_us) / 2;
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/* Does the clock zero the subseconds when time is set? */
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efirtc_zeroes_subseconds = tmcap.tc_stz;
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/*
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* Register. If the clock zeroes out the subseconds when it's set,
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* schedule the SetTime calls to happen just before top-of-second.
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*/
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clock_register_flags(dev, res, CLOCKF_SETTIME_NO_ADJ);
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if (efirtc_zeroes_subseconds)
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clock_schedule(dev, ns_per_s - ns_per_us);
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return (0);
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}
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static int
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efirtc_detach(device_t dev)
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{
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clock_unregister(dev);
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return (0);
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}
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static int
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efirtc_gettime(device_t dev, struct timespec *ts)
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{
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struct clocktime ct;
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struct efi_tm tm;
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int error;
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error = efi_get_time(&tm);
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if (error != 0)
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return (error);
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ct.sec = tm.tm_sec;
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ct.min = tm.tm_min;
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ct.hour = tm.tm_hour;
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ct.day = tm.tm_mday;
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ct.mon = tm.tm_mon;
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ct.year = tm.tm_year;
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ct.nsec = tm.tm_nsec;
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clock_dbgprint_ct(dev, CLOCK_DBG_READ, &ct);
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return (clock_ct_to_ts(&ct, ts));
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}
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static int
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efirtc_settime(device_t dev, struct timespec *ts)
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{
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struct clocktime ct;
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struct efi_tm tm;
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/*
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* We request a timespec with no resolution-adjustment so that we can
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* apply it ourselves based on whether or not the clock zeroes the
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* sub-second part of the time when setting the time.
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*/
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ts->tv_sec -= utc_offset();
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if (!efirtc_zeroes_subseconds)
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timespecadd(ts, &efirtc_resadj, ts);
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clock_ts_to_ct(ts, &ct);
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clock_dbgprint_ct(dev, CLOCK_DBG_WRITE, &ct);
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bzero(&tm, sizeof(tm));
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tm.tm_sec = ct.sec;
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tm.tm_min = ct.min;
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tm.tm_hour = ct.hour;
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tm.tm_mday = ct.day;
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tm.tm_mon = ct.mon;
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tm.tm_year = ct.year;
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tm.tm_nsec = ct.nsec;
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return (efi_set_time(&tm));
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}
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static device_method_t efirtc_methods[] = {
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/* Device interface */
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DEVMETHOD(device_identify, efirtc_identify),
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DEVMETHOD(device_probe, efirtc_probe),
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DEVMETHOD(device_attach, efirtc_attach),
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DEVMETHOD(device_detach, efirtc_detach),
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/* Clock interface */
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DEVMETHOD(clock_gettime, efirtc_gettime),
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DEVMETHOD(clock_settime, efirtc_settime),
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DEVMETHOD_END
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};
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static driver_t efirtc_driver = {
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"efirtc",
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efirtc_methods,
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0
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};
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DRIVER_MODULE(efirtc, nexus, efirtc_driver, 0, 0);
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MODULE_VERSION(efirtc, 1);
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MODULE_DEPEND(efirtc, efirt, 1, 1, 1);
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