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[Qemu-trivial] [PATCH][TRIVIAL] i6300esb: fix timer overflow
From: |
Laurent Vivier |
Subject: |
[Qemu-trivial] [PATCH][TRIVIAL] i6300esb: fix timer overflow |
Date: |
Tue, 4 Aug 2015 10:27:31 +0200 |
We use muldiv64() to compute the time to wait:
timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000);
but get_ticks_per_sec() is 10^9 (30 bit value) and timeout
is a 35 bit value.
Whereas muldiv64 is:
uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
So we loose 3 bits of timeout.
Swapping get_ticks_per_sec() and timeout fixes it.
We can also replace it by a multiplication by 30 ns,
but this changes PCI clock frequency from 33MHz to 33.333333MHz
and we need to do this on all the QEMU PCI devices (later...)
Signed-off-by: Laurent Vivier <address@hidden>
---
hw/watchdog/wdt_i6300esb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c
index cfa2b1b..3e07d44 100644
--- a/hw/watchdog/wdt_i6300esb.c
+++ b/hw/watchdog/wdt_i6300esb.c
@@ -136,7 +136,7 @@ static void i6300esb_restart_timer(I6300State *d, int stage)
* multiply here can exceed 64-bits, before we divide by 33MHz, so
* we use a higher-precision intermediate result.
*/
- timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000);
+ timeout = muldiv64(timeout, get_ticks_per_sec(), 33000000);
i6300esb_debug("stage %d, timeout %" PRIi64 "\n", d->stage, timeout);
--
2.1.0
- [Qemu-trivial] [PATCH][TRIVIAL] i6300esb: fix timer overflow,
Laurent Vivier <=