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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-09-08 01:01:14 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-09-08 01:01:14 -0300
commite5fd91f1ef340da553f7a79da9540c3db711c937 (patch)
treeb11842027dc6641da63f4bcc524f8678263304a3 /drivers/rtc/rtc-efi.c
parent2a9b0348e685a63d97486f6749622b61e9e3292f (diff)
Linux-libre 4.2-gnu
Diffstat (limited to 'drivers/rtc/rtc-efi.c')
-rw-r--r--drivers/rtc/rtc-efi.c43
1 files changed, 16 insertions, 27 deletions
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
index cb989cd00..3806961b4 100644
--- a/drivers/rtc/rtc-efi.c
+++ b/drivers/rtc/rtc-efi.c
@@ -3,7 +3,7 @@
*
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
*
- * Author: dann frazier <dannf@hp.com>
+ * Author: dann frazier <dannf@dannf.org>
* Based on efirtc.c by Stephane Eranian
*
* This program is free software; you can redistribute it and/or modify it
@@ -24,10 +24,6 @@
#include <linux/efi.h>
#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
-/*
- * EFI Epoch is 1/1/1998
- */
-#define EFI_RTC_EPOCH 1998
/*
* returns day of the year [0-365]
@@ -38,31 +34,24 @@ compute_yday(efi_time_t *eft)
/* efi_time_t.month is in the [1-12] so, we need -1 */
return rtc_year_days(eft->day, eft->month - 1, eft->year);
}
+
/*
* returns day of the week [0-6] 0=Sunday
- *
- * Don't try to provide a year that's before 1998, please !
*/
static int
-compute_wday(efi_time_t *eft)
+compute_wday(efi_time_t *eft, int yday)
{
- int y;
- int ndays = 0;
-
- if (eft->year < EFI_RTC_EPOCH) {
- pr_err("EFI year < " __stringify(EFI_RTC_EPOCH) ", invalid date\n");
- return -1;
- }
-
- for (y = EFI_RTC_EPOCH; y < eft->year; y++)
- ndays += 365 + (is_leap_year(y) ? 1 : 0);
-
- ndays += compute_yday(eft);
+ int ndays = eft->year * (365 % 7)
+ + (eft->year - 1) / 4
+ - (eft->year - 1) / 100
+ + (eft->year - 1) / 400
+ + yday;
/*
- * 4=1/1/1998 was a Thursday
+ * 1/1/0000 may or may not have been a Sunday (if it ever existed at
+ * all) but assuming it was makes this calculation work correctly.
*/
- return (ndays + 4) % 7;
+ return ndays % 7;
}
static void
@@ -103,16 +92,16 @@ convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
if (!eft->month || eft->month > 12)
return false;
wtime->tm_mon = eft->month - 1;
- wtime->tm_year = eft->year - 1900;
- /* day of the week [0-6], Sunday=0 */
- wtime->tm_wday = compute_wday(eft);
- if (wtime->tm_wday < 0)
+ if (eft->year < 1900 || eft->year > 9999)
return false;
+ wtime->tm_year = eft->year - 1900;
/* day in the year [1-365]*/
wtime->tm_yday = compute_yday(eft);
+ /* day of the week [0-6], Sunday=0 */
+ wtime->tm_wday = compute_wday(eft, wtime->tm_yday);
switch (eft->daylight & EFI_ISDST) {
case EFI_ISDST:
@@ -233,7 +222,7 @@ static struct platform_driver efi_rtc_driver = {
module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe);
MODULE_ALIAS("platform:rtc-efi");
-MODULE_AUTHOR("dann frazier <dannf@hp.com>");
+MODULE_AUTHOR("dann frazier <dannf@dannf.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("EFI RTC driver");
MODULE_ALIAS("platform:rtc-efi");