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authorLaurent Vivier <lvivier@redhat.com>2015-08-04 10:27:31 +0200
committerMichael Tokarev <mjt@tls.msk.ru>2015-09-11 10:21:38 +0300
commitfee562e9e41290a22623de83b673a8929ec5280d (patch)
tree77fcffdf9d062bdb50bd4bb6ad417002f532ab1d /hw
parent6883de6c9b647d5629ffe131ed5d97c06bb0db1a (diff)
i6300esb: fix timer overflow
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 <lvivier@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Diffstat (limited to 'hw')
-rw-r--r--hw/watchdog/wdt_i6300esb.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c
index cfa2b1be13..3e07d44878 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);