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path: root/drivers/rtc/systohc.c
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Diffstat (limited to 'drivers/rtc/systohc.c')
-rw-r--r--drivers/rtc/systohc.c53
1 files changed, 38 insertions, 15 deletions
diff --git a/drivers/rtc/systohc.c b/drivers/rtc/systohc.c
index b4a68ffcd06b..0c177647ea6c 100644
--- a/drivers/rtc/systohc.c
+++ b/drivers/rtc/systohc.c
@@ -10,6 +10,7 @@
/**
* 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.
@@ -18,30 +19,52 @@
* 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)
+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;
-
- if (now.tv_nsec < (NSEC_PER_SEC >> 1))
- rtc_time64_to_tm(now.tv_sec, &tm);
- else
- rtc_time64_to_tm(now.tv_sec + 1, &tm);
+ bool ok;
rtc = rtc_class_open(CONFIG_RTC_SYSTOHC_DEVICE);
- if (rtc) {
- /* rtc_hctosys exclusively uses UTC, so we call set_time here,
- * not set_mmss. */
- if (rtc->ops &&
- (rtc->ops->set_time ||
- rtc->ops->set_mmss64 ||
- rtc->ops->set_mmss))
- err = rtc_set_time(rtc, &tm);
- rtc_class_close(rtc);
+ 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;
}

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