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author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-25 13:27:36 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-25 13:27:36 -0800 |
commit | 9f9cba810f36d16f4e64477e879a69f6c47b389d (patch) | |
tree | d787abcbead1439d3f82f0719efe520fd9689f79 /arch/s390/include/asm/timex.h | |
parent | dbf5bef8da169b38db804996a661f8d634df8295 (diff) | |
parent | 949db153b6466c6f7cad5a427ecea94985927311 (diff) | |
download | op-kernel-dev-9f9cba810f36d16f4e64477e879a69f6c47b389d.zip op-kernel-dev-9f9cba810f36d16f4e64477e879a69f6c47b389d.tar.gz |
Merge 3.8-rc5 into tty-next
This resolves a number of tty driver merge issues found in linux-next
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390/include/asm/timex.h')
-rw-r--r-- | arch/s390/include/asm/timex.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index fba4d66..4c060bb 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -128,4 +128,32 @@ static inline unsigned long long get_clock_monotonic(void) return get_clock_xt() - sched_clock_base_cc; } +/** + * tod_to_ns - convert a TOD format value to nanoseconds + * @todval: to be converted TOD format value + * Returns: number of nanoseconds that correspond to the TOD format value + * + * Converting a 64 Bit TOD format value to nanoseconds means that the value + * must be divided by 4.096. In order to achieve that we multiply with 125 + * and divide by 512: + * + * ns = (todval * 125) >> 9; + * + * In order to avoid an overflow with the multiplication we can rewrite this. + * With a split todval == 2^32 * th + tl (th upper 32 bits, tl lower 32 bits) + * we end up with + * + * ns = ((2^32 * th + tl) * 125 ) >> 9; + * -> ns = (2^23 * th * 125) + ((tl * 125) >> 9); + * + */ +static inline unsigned long long tod_to_ns(unsigned long long todval) +{ + unsigned long long ns; + + ns = ((todval >> 32) << 23) * 125; + ns += ((todval & 0xffffffff) * 125) >> 9; + return ns; +} + #endif |