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authorLaurent Vivier <lvivier@redhat.com>2015-08-25 16:16:21 +0200
committerLaurent Vivier <lvivier@redhat.com>2015-09-25 14:54:04 +0200
commit683dca6bd5057a87d9376475b0c7e30d56d8e532 (patch)
treee9a0ca88dcaf7bd08c4044b1ad0ff9c21478d57f /hw/openrisc/cputimer.c
parentc6acbe861f1ed4203f4864baf756686064ba561f (diff)
downloadfocaccia-qemu-683dca6bd5057a87d9376475b0c7e30d56d8e532.tar.gz
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mips: 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 MIPS timer frequency is 100 MHz, we can also do:

    y = x * 10; /* 100 MHz period is 10 ns */

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Diffstat (limited to 'hw/openrisc/cputimer.c')
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