[U-Boot] [PATCH v2 1/6] drivers: rtc: resolve year 2038 problem in rtc_to_tm
Heinrich Schuchardt
xypron.glpk at gmx.de
Sat Jul 7 21:39:11 UTC 2018
Our implementation of rtc_to_tm() cannot handle dates of more than
0x7fffffff seconds after 1970-01-01.
Adopt the Linux kernel implementation.
Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
v2
adopt the Linux kernel implementation
---
drivers/rtc/Makefile | 1 +
drivers/rtc/date.c | 43 ----------------------
drivers/rtc/i2c_rtc_emul.c | 4 ++-
drivers/rtc/rtc-lib.c | 73 ++++++++++++++++++++++++++++++++++++++
include/rtc.h | 16 +++++++--
5 files changed, 90 insertions(+), 47 deletions(-)
create mode 100644 drivers/rtc/rtc-lib.c
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 09f2b08244..513e3ffc07 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_DM_RTC) += rtc-uclass.o
obj-$(CONFIG_RTC_AT91SAM9_RTT) += at91sam9_rtt.o
obj-y += date.o
+obj-y += rtc-lib.o
obj-$(CONFIG_RTC_DAVINCI) += davinci.o
obj-$(CONFIG_RTC_DS1302) += ds1302.o
obj-$(CONFIG_RTC_DS1306) += ds1306.o
diff --git a/drivers/rtc/date.c b/drivers/rtc/date.c
index 1256ffe374..f2568cf886 100644
--- a/drivers/rtc/date.c
+++ b/drivers/rtc/date.c
@@ -19,10 +19,6 @@
#define days_in_year(a) (leapyear(a) ? 366 : 365)
#define days_in_month(a) (month_days[(a) - 1])
-static int month_days[12] = {
- 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
-};
-
static int month_offset[] = {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
@@ -65,45 +61,6 @@ int rtc_calc_weekday(struct rtc_time *tm)
return 0;
}
-int rtc_to_tm(int tim, struct rtc_time *tm)
-{
- register int i;
- register long hms, day;
-
- day = tim / SECDAY;
- hms = tim % SECDAY;
-
- /* Hours, minutes, seconds are easy */
- tm->tm_hour = hms / 3600;
- tm->tm_min = (hms % 3600) / 60;
- tm->tm_sec = (hms % 3600) % 60;
-
- /* Number of years in days */
- for (i = STARTOFTIME; day >= days_in_year(i); i++)
- day -= days_in_year(i);
- tm->tm_year = i;
-
- /* Number of months in days left */
- if (leapyear(tm->tm_year))
- days_in_month(FEBRUARY) = 29;
- for (i = 1; day >= days_in_month(i); i++)
- day -= days_in_month(i);
- days_in_month(FEBRUARY) = 28;
- tm->tm_mon = i;
-
- /* Days are what is left over (+1) from all that */
- tm->tm_mday = day + 1;
-
- /* Zero unused fields */
- tm->tm_yday = 0;
- tm->tm_isdst = 0;
-
- /*
- * Determine the day of week
- */
- return rtc_calc_weekday(tm);
-}
-
/*
* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
diff --git a/drivers/rtc/i2c_rtc_emul.c b/drivers/rtc/i2c_rtc_emul.c
index bad61c377f..d4b33e59d6 100644
--- a/drivers/rtc/i2c_rtc_emul.c
+++ b/drivers/rtc/i2c_rtc_emul.c
@@ -96,7 +96,9 @@ static int sandbox_i2c_rtc_get(struct udevice *dev, struct rtc_time *time)
now = plat->base_time;
}
- return rtc_to_tm(now + plat->offset, time);
+ rtc_to_tm(now + plat->offset, time);
+
+ return 0;
}
static int sandbox_i2c_rtc_set(struct udevice *dev, const struct rtc_time *time)
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
new file mode 100644
index 0000000000..b8a7a8b2d3
--- /dev/null
+++ b/drivers/rtc/rtc-lib.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * rtc and date/time utility functions
+ *
+ * Copyright (C) 2005-06 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo at towertech.it>
+ *
+ * U-Boot rtc_time differs from Linux rtc_time:
+ * - The year field takes the actual value, not year - 1900.
+ * - January is month 1.
+ */
+
+#include <common.h>
+#include <rtc.h>
+#include <linux/math64.h>
+
+static const unsigned char rtc_days_in_month[] = {
+ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+#define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
+
+/*
+ * The number of days in the month.
+ */
+static int rtc_month_days(unsigned int month, unsigned int year)
+{
+ return rtc_days_in_month[month] + (is_leap_year(year) && month == 1);
+}
+
+/*
+ * rtc_to_tm - Converts u64 to rtc_time.
+ * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
+ */
+void rtc_to_tm(u64 time, struct rtc_time *tm)
+{
+ unsigned int month, year, secs, days;
+
+ days = div_u64_rem(time, 86400, &secs);
+
+ /* day of the week, 1970-01-01 was a Thursday */
+ tm->tm_wday = (days + 4) % 7;
+
+ year = 1970 + days / 365;
+ days -= (year - 1970) * 365
+ + LEAPS_THRU_END_OF(year - 1)
+ - LEAPS_THRU_END_OF(1970 - 1);
+ while (days < 0) {
+ year -= 1;
+ days += 365 + is_leap_year(year);
+ }
+ tm->tm_year = year; /* Not year - 1900 */
+ tm->tm_yday = days + 1;
+
+ for (month = 0; month < 11; month++) {
+ int newdays;
+
+ newdays = days - rtc_month_days(month, year);
+ if (newdays < 0)
+ break;
+ days = newdays;
+ }
+ tm->tm_mon = month + 1; /* January = 1 */
+ tm->tm_mday = days + 1;
+
+ tm->tm_hour = secs / 3600;
+ secs -= tm->tm_hour * 3600;
+ tm->tm_min = secs / 60;
+ tm->tm_sec = secs - tm->tm_min * 60;
+
+ /* Zero unused fields */
+ tm->tm_isdst = 0;
+}
diff --git a/include/rtc.h b/include/rtc.h
index 746624d799..0d964d56d5 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -208,7 +208,18 @@ void rtc_write32(int reg, u32 value);
* rtc_init() - Set up the real time clock ready for use
*/
void rtc_init(void);
-#endif
+#endif /* CONFIG_DM_RTC */
+
+/**
+ * is_leap_year - Check if year is a leap year
+ *
+ * @year Year
+ * @return 1 if leap year
+ */
+static inline bool is_leap_year(unsigned int year)
+{
+ return (!(year % 4) && (year % 100)) || !(year % 400);
+}
/**
* rtc_calc_weekday() - Work out the weekday from a time
@@ -231,9 +242,8 @@ int rtc_calc_weekday(struct rtc_time *time);
*
* @time_t: Number of seconds since 1970-01-01 00:00:00
* @time: Place to put the broken-out time
- * @return 0 if OK, -EINVAL if the weekday could not be determined
*/
-int rtc_to_tm(int time_t, struct rtc_time *time);
+void rtc_to_tm(u64 time_t, struct rtc_time *time);
/**
* rtc_mktime() - Convert a broken-out time into a time_t value
--
2.18.0
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