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ntp, rtc: Move rtc_set_ntp_time() to ntp code

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rtc_set_ntp_time() is not really RTC functionality as the code is just a
user of RTC. Move it into the NTP code which allows further cleanups.

Requested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201206220542.166871172@linutronix.de
This commit is contained in:
Thomas Gleixner
2020-12-11 10:40:52 +01:00
parent c9e6189fb0
commit 33e62e8323
4 changed files with 85 additions and 99 deletions
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kernel/time/ntp.c
+85 -3
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@@ -519,15 +519,94 @@ static void sched_sync_hw_clock(unsigned long offset_nsec, bool retry)
hrtimer_start(&sync_hrtimer, exp, HRTIMER_MODE_ABS);
}
/*
* Determine if we can call to driver to set the time. Drivers can only be
* called to set a second aligned time value, and the field set_offset_nsec
* specifies how far away from the second aligned time to call the driver.
*
* This also computes 'to_set' which is the time we are trying to set, and has
* a zero in tv_nsecs, such that:
* to_set - set_delay_nsec == now +/- FUZZ
*
*/
static inline bool rtc_tv_nsec_ok(long set_offset_nsec,
struct timespec64 *to_set,
const struct timespec64 *now)
{
/* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
struct timespec64 delay = {.tv_sec = 0,
.tv_nsec = set_offset_nsec};
*to_set = timespec64_add(*now, delay);
if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
to_set->tv_nsec = 0;
return true;
}
if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
to_set->tv_sec++;
to_set->tv_nsec = 0;
return true;
}
return false;
}
#ifdef CONFIG_RTC_SYSTOHC
/*
* rtc_set_ntp_time - Save NTP synchronized time to the RTC
*/
static 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)
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);
err = rtc_set_time(rtc, &tm);
out_close:
rtc_class_close(rtc);
out_err:
return err;
}
static void sync_rtc_clock(void)
{
unsigned long offset_nsec;
struct timespec64 adjust;
int rc;
if (!IS_ENABLED(CONFIG_RTC_SYSTOHC))
return;
ktime_get_real_ts64(&adjust);
if (persistent_clock_is_local)
@@ -544,6 +623,9 @@ static void sync_rtc_clock(void)
sched_sync_hw_clock(offset_nsec, rc != 0);
}
#else
static inline void sync_rtc_clock(void) { }
#endif
#ifdef CONFIG_GENERIC_CMOS_UPDATE
int __weak update_persistent_clock64(struct timespec64 now64)