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authorLaurent Vivier <lvivier@redhat.com>2015-08-24 19:29:45 +0200
committerLaurent Vivier <lvivier@redhat.com>2015-09-25 14:53:29 +0200
commit37b9ab92f7f8295c61daa4a8893eb8fb1add63e2 (patch)
tree92c9a4c83231fdd65ae066f4571fcd9e1cba2ce2 /hw
parent9491e9bc019a365dfa9780f462984a0d052f4c0d (diff)
rtl8139: 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(), PCI_FREQUENCY) 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 PCI frequency is 33 MHz, we can also do: y = x * 30; /* 33 MHz PCI period is 30 ns */ Which is much more simple. This implies a 33.333333 MHz PCI frequency, but this is correct. Signed-off-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/net/rtl8139.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index b0d6c40f58..68e43f3d48 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -64,7 +64,7 @@
/* debug RTL8139 card */
//#define DEBUG_RTL8139 1
-#define PCI_FREQUENCY 33000000L
+#define PCI_PERIOD 30 /* 30 ns period = 33.333333 Mhz frequency */
#define SET_MASKED(input, mask, curr) \
( ( (input) & ~(mask) ) | ( (curr) & (mask) ) )
@@ -2834,8 +2834,7 @@ static void rtl8139_io_writew(void *opaque, uint8_t addr, uint32_t val)
static void rtl8139_set_next_tctr_time(RTL8139State *s)
{
- const uint64_t ns_per_period =
- muldiv64(0x100000000LL, get_ticks_per_sec(), PCI_FREQUENCY);
+ const uint64_t ns_per_period = (uint64_t)PCI_PERIOD << 32;
DPRINTF("entered rtl8139_set_next_tctr_time\n");
@@ -2853,7 +2852,7 @@ static void rtl8139_set_next_tctr_time(RTL8139State *s)
if (!s->TimerInt) {
timer_del(s->timer);
} else {
- uint64_t delta = muldiv64(s->TimerInt, get_ticks_per_sec(), PCI_FREQUENCY);
+ uint64_t delta = (uint64_t)s->TimerInt * PCI_PERIOD;
if (s->TCTR_base + delta <= qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)) {
delta += ns_per_period;
}
@@ -3127,8 +3126,8 @@ static uint32_t rtl8139_io_readl(void *opaque, uint8_t addr)
break;
case Timer:
- ret = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - s->TCTR_base,
- PCI_FREQUENCY, get_ticks_per_sec());
+ ret = (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - s->TCTR_base) /
+ PCI_PERIOD;
DPRINTF("TCTR Timer read val=0x%08x\n", ret);
break;
@@ -3222,8 +3221,7 @@ static void rtl8139_pre_save(void *opaque)
int64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
/* for migration to older versions */
- s->TCTR = muldiv64(current_time - s->TCTR_base, PCI_FREQUENCY,
- get_ticks_per_sec());
+ s->TCTR = (current_time - s->TCTR_base) / PCI_PERIOD;
s->rtl8139_mmio_io_addr_dummy = 0;
}