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authorFinn Thain <fthain@telegraphics.com.au>2018-04-23 04:02:57 +0300
committerGeert Uytterhoeven <geert@linux-m68k.org>2018-05-22 11:31:50 +0300
commitb65769fc013edb7c2e5fdcd91ea6124ad76168f5 (patch)
treeb6ad02cfbf7a81d1a4f339d0873fabb71b8b549e /arch/m68k/68000
parent4eee57d68b8b2e6e0a6960c0bacf93448e4ae214 (diff)
downloadlinux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.tar.xz
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/68000')
-rw-r--r--arch/m68k/68000/timers.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/m68k/68000/timers.c b/arch/m68k/68000/timers.c
index 252455bce144..71ddb4c98726 100644
--- a/arch/m68k/68000/timers.c
+++ b/arch/m68k/68000/timers.c
@@ -125,7 +125,9 @@ int m68328_hwclk(int set, struct rtc_time *t)
{
if (!set) {
long now = RTCTIME;
- t->tm_year = t->tm_mon = t->tm_mday = 1;
+ t->tm_year = 1;
+ t->tm_mon = 0;
+ t->tm_mday = 1;
t->tm_hour = (now >> 24) % 24;
t->tm_min = (now >> 16) % 60;
t->tm_sec = now % 60;