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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/sun3x | |
| parent | 4eee57d68b8b2e6e0a6960c0bacf93448e4ae214 (diff) | |
| download | linux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.tar.gz linux-b65769fc013edb7c2e5fdcd91ea6124ad76168f5.tar.bz2 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/sun3x')
| -rw-r--r-- | arch/m68k/sun3x/time.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/m68k/sun3x/time.c b/arch/m68k/sun3x/time.c index 7a2c53d9f779..047e2bcee3d7 100644 --- a/arch/m68k/sun3x/time.c +++ b/arch/m68k/sun3x/time.c @@ -52,8 +52,8 @@ int sun3x_hwclk(int set, struct rtc_time *t) h->hour = bin2bcd(t->tm_hour); h->wday = bin2bcd(t->tm_wday); h->mday = bin2bcd(t->tm_mday); - h->month = bin2bcd(t->tm_mon); - h->year = bin2bcd(t->tm_year); + h->month = bin2bcd(t->tm_mon + 1); + h->year = bin2bcd(t->tm_year % 100); h->csr &= ~C_WRITE; } else { h->csr |= C_READ; @@ -62,9 +62,11 @@ int sun3x_hwclk(int set, struct rtc_time *t) t->tm_hour = bcd2bin(h->hour); t->tm_wday = bcd2bin(h->wday); t->tm_mday = bcd2bin(h->mday); - t->tm_mon = bcd2bin(h->month); + t->tm_mon = bcd2bin(h->month) - 1; t->tm_year = bcd2bin(h->year); h->csr &= ~C_READ; + if (t->tm_year < 70) + t->tm_year += 100; } local_irq_restore(flags); |