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authorLaurent Vivier <lvivier@redhat.com>2015-08-25 17:17:15 +0200
committerLaurent Vivier <lvivier@redhat.com>2015-09-25 14:54:22 +0200
commitccaf1749239aa33c5a5b755972232ffe1c0cf946 (patch)
treec52fc1d092f37976f1503a64d3613c1b48ac8a3e /hw
parent683dca6bd5057a87d9376475b0c7e30d56d8e532 (diff)
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>
Diffstat (limited to 'hw')
-rw-r--r--hw/openrisc/cputimer.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/hw/openrisc/cputimer.c b/hw/openrisc/cputimer.c
index 9c54945107..560cb914c5 100644
--- a/hw/openrisc/cputimer.c
+++ b/hw/openrisc/cputimer.c
@@ -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);
}