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authorFinn Thain <fthain@telegraphics.com.au>2018-04-23 03:02:57 +0200
committerGeert Uytterhoeven <geert@linux-m68k.org>2018-05-22 10:31:50 +0200
commitb65769fc013edb7c2e5fdcd91ea6124ad76168f5 (patch)
treeb6ad02cfbf7a81d1a4f339d0873fabb71b8b549e /arch/m68k/sun3
parentm68k: Fix style, spelling, and grammar in siginfo_build_tests() (diff)
downloadlinux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.tar.xz
linux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.zip
m68k: Fix off-by-one calendar month
This fixes a bug in read_persistent_clock() which causes the system clock to lag the Real Time Clock by one month. The problem was noticed on a Mac, but theoretically it must also affect Atari, BVME6000 and Q40. The tm_mon value in the struct rtc_time passed to mach_hwclk() is zero-based, and atari_mste_hwclk(), atari_tt_hwclk(), bvme6000_hwclk(), mac_hwclk() and q40_hwclk() all make this adjustment. Unfortunately, dn_dummy_hwclk(), mvme147_hwclk(), mvme16x_hwclk(), sun3_hwclk() and sun3x_hwclk() fail to decrement tm_mon. Also m68328_hwclk() assumes a one-based tm_mon. Bring these platforms into line and fix read_persistent_clock() so it works correctly on all m68k platforms. The datasheets for the RTC devices found on the affected platforms all confirm that the year is stored as a value in the range 0-99 and the month is stored as a value in the range 1-12. Please refer to the datasheets for MC146818 (Apollo), DS1643 (MVME), ICM7170 (Sun 3) and M48T02 (Sun 3x). Reported-by: Stan Johnson <userm57@yahoo.com> Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Diffstat (limited to 'arch/m68k/sun3')
-rw-r--r--arch/m68k/sun3/intersil.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/m68k/sun3/intersil.c b/arch/m68k/sun3/intersil.c
index 2cd0bcbe6f30..d911070af02a 100644
--- a/arch/m68k/sun3/intersil.c
+++ b/arch/m68k/sun3/intersil.c
@@ -48,9 +48,9 @@ int sun3_hwclk(int set, struct rtc_time *t)
todintersil->hour = t->tm_hour;
todintersil->minute = t->tm_min;
todintersil->second = t->tm_sec;
- todintersil->month = t->tm_mon;
+ todintersil->month = t->tm_mon + 1;
todintersil->day = t->tm_mday;
- todintersil->year = t->tm_year - 68;
+ todintersil->year = (t->tm_year - 68) % 100;
todintersil->weekday = t->tm_wday;
} else {
/* read clock */
@@ -58,10 +58,12 @@ int sun3_hwclk(int set, struct rtc_time *t)
t->tm_hour = todintersil->hour;
t->tm_min = todintersil->minute;
t->tm_sec = todintersil->second;
- t->tm_mon = todintersil->month;
+ t->tm_mon = todintersil->month - 1;
t->tm_mday = todintersil->day;
t->tm_year = todintersil->year + 68;
t->tm_wday = todintersil->weekday;
+ if (t->tm_year < 70)
+ t->tm_year += 100;
}
intersil_clock->cmd_reg = START_VAL;