71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
/*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published by
|
|
* the Free Software Foundation.
|
|
*
|
|
*/
|
|
#include <linux/rtc.h>
|
|
#include <linux/time.h>
|
|
|
|
/**
|
|
* rtc_set_ntp_time - Save NTP synchronized time to the RTC
|
|
* @now: Current time of day
|
|
* @target_nsec: pointer for desired now->tv_nsec value
|
|
*
|
|
* Replacement for the NTP platform function update_persistent_clock64
|
|
* that stores time for later retrieval by rtc_hctosys.
|
|
*
|
|
* Returns 0 on successful RTC update, -ENODEV if a RTC update is not
|
|
* possible at all, and various other -errno for specific temporary failure
|
|
* cases.
|
|
*
|
|
* -EPROTO is returned if now.tv_nsec is not close enough to *target_nsec.
|
|
*
|
|
* If temporary failure is indicated the caller should try again 'soon'
|
|
*/
|
|
int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec)
|
|
{
|
|
struct rtc_device *rtc;
|
|
struct rtc_time tm;
|
|
struct timespec64 to_set;
|
|
int err = -ENODEV;
|
|
bool ok;
|
|
|
|
rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
|
|
if (!rtc)
|
|
goto out_err;
|
|
|
|
if (!rtc->ops || (!rtc->ops->set_time && !rtc->ops->set_mmss64 &&
|
|
!rtc->ops->set_mmss))
|
|
goto out_close;
|
|
|
|
/* Compute the value of tv_nsec we require the caller to supply in
|
|
* now.tv_nsec. This is the value such that (now +
|
|
* set_offset_nsec).tv_nsec == 0.
|
|
*/
|
|
set_normalized_timespec64(&to_set, 0, -rtc->set_offset_nsec);
|
|
*target_nsec = to_set.tv_nsec;
|
|
|
|
/* The ntp code must call this with the correct value in tv_nsec, if
|
|
* it does not we update target_nsec and return EPROTO to make the ntp
|
|
* code try again later.
|
|
*/
|
|
ok = rtc_tv_nsec_ok(rtc->set_offset_nsec, &to_set, &now);
|
|
if (!ok) {
|
|
err = -EPROTO;
|
|
goto out_close;
|
|
}
|
|
|
|
rtc_time64_to_tm(to_set.tv_sec, &tm);
|
|
|
|
/* rtc_hctosys exclusively uses UTC, so we call set_time here, not
|
|
* set_mmss.
|
|
*/
|
|
err = rtc_set_time(rtc, &tm);
|
|
|
|
out_close:
|
|
rtc_class_close(rtc);
|
|
out_err:
|
|
return err;
|
|
}
|