int err;
struct rtc_time before, now;
int first_time = 1;
+ unsigned long t_now, t_alm;
+ enum { none, day, month, year } missing = none;
+ unsigned days;
- /* The lower level RTC driver may not be capable of filling
- * in all fields of the rtc_time struct (eg. rtc-cmos),
- * and so might instead return -1 in some fields.
- * We deal with that here by grabbing a current RTC timestamp
- * and using values from that for any missing (-1) values.
+ /* The lower level RTC driver may return -1 in some fields,
+ * creating invalid alarm->time values, for reasons like:
+ *
+ * - The hardware may not be capable of filling them in;
+ * many alarms match only on time-of-day fields, not
+ * day/month/year calendar data.
+ *
+ * - Some hardware uses illegal values as "wildcard" match
+ * values, which non-Linux firmware (like a BIOS) may try
+ * to set up as e.g. "alarm 15 minutes after each hour".
+ * Linux uses only oneshot alarms.
+ *
+ * When we see that here, we deal with it by using values from
+ * a current RTC timestamp for any missing (-1) values. The
+ * RTC driver prevents "periodic alarm" modes.
*
* But this can be racey, because some fields of the RTC timestamp
* may have wrapped in the interval since we read the RTC alarm,
if (!alarm->enabled)
return 0;
+ /* full-function RTCs won't have such missing fields */
+ if (rtc_valid_tm(&alarm->time) == 0)
+ return 0;
+
/* get the "after" timestamp, to detect wrapped fields */
err = rtc_read_time(rtc, &now);
if (err < 0)
} while ( before.tm_min != now.tm_min
|| before.tm_hour != now.tm_hour
|| before.tm_mon != now.tm_mon
- || before.tm_year != now.tm_year
- || before.tm_isdst != now.tm_isdst);
+ || before.tm_year != now.tm_year);
- /* Fill in any missing alarm fields using the timestamp */
+ /* Fill in the missing alarm fields using the timestamp; we
+ * know there's at least one since alarm->time is invalid.
+ */
if (alarm->time.tm_sec == -1)
alarm->time.tm_sec = now.tm_sec;
if (alarm->time.tm_min == -1)
alarm->time.tm_min = now.tm_min;
if (alarm->time.tm_hour == -1)
alarm->time.tm_hour = now.tm_hour;
- if (alarm->time.tm_mday == -1)
+
+ /* For simplicity, only support date rollover for now */
+ if (alarm->time.tm_mday == -1) {
alarm->time.tm_mday = now.tm_mday;
- if (alarm->time.tm_mon == -1)
+ missing = day;
+ }
+ if (alarm->time.tm_mon == -1) {
alarm->time.tm_mon = now.tm_mon;
- if (alarm->time.tm_year == -1)
+ if (missing == none)
+ missing = month;
+ }
+ if (alarm->time.tm_year == -1) {
alarm->time.tm_year = now.tm_year;
+ if (missing == none)
+ missing = year;
+ }
+
+ /* with luck, no rollover is needed */
+ rtc_tm_to_time(&now, &t_now);
+ rtc_tm_to_time(&alarm->time, &t_alm);
+ if (t_now < t_alm)
+ goto done;
+
+ switch (missing) {
+
+ /* 24 hour rollover ... if it's now 10am Monday, an alarm that
+ * that will trigger at 5am will do so at 5am Tuesday, which
+ * could also be in the next month or year. This is a common
+ * case, especially for PCs.
+ */
+ case day:
+ dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
+ t_alm += 24 * 60 * 60;
+ rtc_time_to_tm(t_alm, &alarm->time);
+ break;
+
+ /* Month rollover ... if it's the 31th, an alarm on the 3rd will
+ * be next month. An alarm matching on the 30th, 29th, or 28th
+ * may end up in the month after that! Many newer PCs support
+ * this type of alarm.
+ */
+ case month:
+ dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
+ do {
+ if (alarm->time.tm_mon < 11)
+ alarm->time.tm_mon++;
+ else {
+ alarm->time.tm_mon = 0;
+ alarm->time.tm_year++;
+ }
+ days = rtc_month_days(alarm->time.tm_mon,
+ alarm->time.tm_year);
+ } while (days < alarm->time.tm_mday);
+ break;
+
+ /* Year rollover ... easy except for leap years! */
+ case year:
+ dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
+ do {
+ alarm->time.tm_year++;
+ } while (!rtc_valid_tm(&alarm->time));
+ break;
+
+ default:
+ dev_warn(&rtc->dev, "alarm rollover not handled\n");
+ }
+
+done:
return 0;
}
EXPORT_SYMBOL_GPL(rtc_read_alarm);
struct device *dev;
struct rtc_device *rtc = NULL;
- dev = class_find_device(rtc_class, name, __rtc_match);
+ dev = class_find_device(rtc_class, NULL, name, __rtc_match);
if (dev)
rtc = to_rtc_device(dev);
git.openpandora.org / pandora-kernel.git / blobdiff