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| /openbmc/qemu/hw/openrisc/ |
| H A D | cputimer.c | ccaf1749 Tue Aug 25 10:17:15 CDT 2015 Laurent Vivier <lvivier@redhat.com> openrisc: remove muldiv64()
Originally, timers were ticks based, and it made sense to
add ticks to current time to know when to trigger an alarm.
But since commit:
7447545 change all other clock references to use nanosecond resolution accessors
All timers use nanoseconds and we need to convert ticks to nanoseconds, by
doing something like:
y = muldiv64(x, get_ticks_per_sec(), TIMER_FREQ)
where x is the number of device ticks and y the number of system ticks.
y is used as nanoseconds in timer functions,
it works because 1 tick is 1 nanosecond.
(get_ticks_per_sec() is 10^9)
But as openrisc timer frequency is 20 MHz, we can also do:
y = x * 50; /* 20 MHz period is 50 ns */
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
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