提交 ccaf1749 编写于 作者: L Laurent Vivier

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:

74475455 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: NLaurent Vivier <lvivier@redhat.com>
上级 683dca6b
......@@ -22,7 +22,7 @@
#include "hw/hw.h"
#include "qemu/timer.h"
#define TIMER_FREQ (20 * 1000 * 1000) /* 20MHz */
#define TIMER_PERIOD 50 /* 50 ns period for 20 MHz timer */
/* The time when TTCR changes */
static uint64_t last_clk;
......@@ -36,8 +36,7 @@ void cpu_openrisc_count_update(OpenRISCCPU *cpu)
return;
}
now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
cpu->env.ttcr += (uint32_t)muldiv64(now - last_clk, TIMER_FREQ,
get_ticks_per_sec());
cpu->env.ttcr += (uint32_t)((now - last_clk) / TIMER_PERIOD);
last_clk = now;
}
......@@ -59,7 +58,7 @@ void cpu_openrisc_timer_update(OpenRISCCPU *cpu)
} else {
wait = (cpu->env.ttmr & TTMR_TP) - (cpu->env.ttcr & TTMR_TP);
}
next = now + muldiv64(wait, get_ticks_per_sec(), TIMER_FREQ);
next = now + (uint64_t)wait * TIMER_PERIOD;
timer_mod(cpu->env.timer, next);
}
......
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