cvs commit: src/sys/dev/mk48txx mk48txx.c mk48txxreg.h

[John Baldwin]

On Sunday 19 September 2004 05:38 pm, Marius Strobl wrote:
> marius      2004-09-19 21:38:11 UTC
>
>   FreeBSD src repository
>
>   Modified files:
>     sys/dev/mk48txx      mk48txx.c mk48txxreg.h
>   Log:
>   - Some of the upper bits of the time related (seconds, minutes, etc.)
>     registers are control bits or depending on the model contain additional
>     time bits with a different meaning than the lower ones. In order to
>     only read the desired time bits and not change the upper bits on write
>     use appropriate masks in the gettime and settime function respectively.
>     Due to the polarity of the stop oscillator bit and the fact that the
>     century bits aren't used on sparc64 not masking them didn't cause
>     problems so far.
>   - Fix two off-by-one errors in the handling of the day of week. The
>     genclock code represents the dow as 0 - 6 with 0 being Sunday but the
>     mk48txx use 1 - 7 with 1 being Sunday. In the settime function when
>     writing the dow to the clock the range wasn't adjusted accordingly but
>     the clock apparently played along nicely otherwise the second bug in
>     the gettime function which mapped 1 - 7 to 0 - 6 but with 0 meaning
>     Saturday would have been triggered. Fixing these makes the date being
>     stored in the same format Sun/Solaris uses and cures the "Invalid time
>     in real time clock. Check and reset the date immediately!" when the
>     date was set under Solaris prior to booting FreeBSD/sparc64. [1]
>     Looking at other clock drivers/code e.g. FreeBSD/alpha the former
> "bug", i.e. storing the dow as 0 - 6 even when the clock uses 1 - 7, seems
> to be common but might be on purpose for compatibility when multi-booting
> with other OS which do the same. So it might make sense to add a flag to
> handle the dow off-by-one for use of this driver on platforms other than
> sparc64.

Hmm, I get them occasionally on my Alphas which only run FreeBSD, so I think 
it's probably a bug that needs to be fixed in FreeBSD/alpha.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org