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| author | Finn Thain <fthain@telegraphics.com.au> | 2018-04-23 11:02:57 +1000 |
|---|---|---|
| committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2018-05-22 10:31:50 +0200 |
| commit | b65769fc013edb7c2e5fdcd91ea6124ad76168f5 (patch) | |
| tree | b6ad02cfbf7a81d1a4f339d0873fabb71b8b549e /arch/m68k/sun3 | |
| parent | 4eee57d68b8b2e6e0a6960c0bacf93448e4ae214 (diff) | |
| download | linux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.tar.gz | |
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.c | 8 |
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; |