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Subject[PATCH 1/4] rtc-lib: Add rtc_show_time(const char *prefix_msg)
Date
Go directly to the rtc for persistent wall clock time and print.
Useful if REALTIME is required to be logged in a low level power
management function or when clock activities are suspended. An
aid to permit user space alignment of kernel activities.

Feature activated by CONFIG_RTC_SHOW_TIME.

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
---
drivers/rtc/Kconfig | 11 +++++++++++
drivers/rtc/rtc-lib.c | 16 ++++++++++++++++
include/linux/rtc.h | 5 +++++
3 files changed, 32 insertions(+)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 72419ac2c52a..7c308605bf42 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -5,6 +5,17 @@
config RTC_LIB
bool

+config RTC_SHOW_TIME
+ bool "rtc_show_time instrumentation"
+ select RTC_LIB
+ help
+ Activate rtc_show_time(const char *msg) wall clock time
+ instrumentation.
+
+ The instrumentation is used to help triage and synchronize
+ kernel logs using CLOCK_MONOTONIC and user space activity
+ logs utilizing CLOCK_REALTIME references.
+
config RTC_MC146818_LIB
bool
select RTC_LIB
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index 1ae7da5cfc60..676d6a83e843 100644
--- a/drivers/rtc/rtc-lib.c
+++ b/drivers/rtc/rtc-lib.c
@@ -94,6 +94,22 @@ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm)
}
EXPORT_SYMBOL(rtc_time64_to_tm);

+#ifdef CONFIG_RTC_SHOW_TIME
+void rtc_show_time(const char *prefix_msg)
+{
+ struct timespec ts;
+ struct rtc_time tm;
+
+ getnstimeofday(&ts);
+ rtc_time_to_tm(ts.tv_sec, &tm);
+ pr_info("%s %d-%02d-%02d %02d:%02d:%02d.%09lu UTC\n",
+ prefix_msg ? prefix_msg : "Time:",
+ tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+ tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
+}
+EXPORT_SYMBOL(rtc_show_time);
+#endif
+
/*
* Does the rtc_time represent a valid date/time?
*/
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 0a0f0d14a5fb..bf625e023799 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -22,6 +22,11 @@ extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year
extern int rtc_valid_tm(struct rtc_time *tm);
extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
+#ifdef CONFIG_RTC_SHOW_TIME
+extern void rtc_show_time(const char *prefix_msg);
+#else
+#define rtc_show_time(prefix_msg)
+#endif
ktime_t rtc_tm_to_ktime(struct rtc_time tm);
struct rtc_time rtc_ktime_to_tm(ktime_t kt);

--
2.13.2.932.g7449e964c-goog
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