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[Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks in
From: |
Laurent Vivier |
Subject: |
[Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds |
Date: |
Mon, 3 Aug 2015 15:52:28 +0200 |
Originally, qemu_mod_timer() was using ticks to count time.
And i6300esb was converting internal clock ticks (33 MHz) to
QEMU timer ticks.
The timer has been changed by a script to use nanoseconds:
7447545 change all other clock references to use
nanosecond resolution accessors
As i6300esb takes nanoseconds, we don't need anymore to
multiply counter by get_ticks_per_sec()/33MHz, but instead
we must convert watchdog ticks into nanoseconds.
Signed-off-by: Laurent Vivier <address@hidden>
---
hw/watchdog/wdt_i6300esb.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c
index cfa2b1b..21119ab 100644
--- a/hw/watchdog/wdt_i6300esb.c
+++ b/hw/watchdog/wdt_i6300esb.c
@@ -124,19 +124,24 @@ static void i6300esb_restart_timer(I6300State *d, int
stage)
else
timeout = d->timer2_preload;
- if (d->clock_scale == CLOCK_SCALE_1KHZ)
+ /* convert timeout to 33Mhz clock ticks */
+ if (d->clock_scale == CLOCK_SCALE_1KHZ) {
+ /* The 20-bit Preload Value is loaded into bits 34:15 of the
+ * main down counter. [...] The approximate clock generated
+ * is 1 KHz, (Default)
+ */
timeout <<= 15;
- else
+ } else {
+ /* The 20-bit Preload Value is loaded into bits 24:5 of the
+ * main down counter. [...] The approximate clock generated
+ * is 1 MHz.
+ */
timeout <<= 5;
-
- /* Get the timeout in units of ticks_per_sec.
- *
- * ticks_per_sec is typically 10^9 == 0x3B9ACA00 (30 bits), with
- * 20 bits of user supplied preload, and 15 bits of scale, the
- * multiply here can exceed 64-bits, before we divide by 33MHz, so
- * we use a higher-precision intermediate result.
+ }
+ /* A 33 Mhz clock gives a 30 ns tick,
+ * convert timeout from ticks to ns
*/
- timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000);
+ timeout *= 30;
i6300esb_debug("stage %d, timeout %" PRIi64 "\n", d->stage, timeout);
--
2.1.0
- [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds,
Laurent Vivier <=
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Laurent Vivier, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Richard W.M. Jones, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Paolo Bonzini, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Laurent Vivier, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Paolo Bonzini, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Laurent Vivier, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Paolo Bonzini, 2015/08/03
- Re: [Qemu-devel] [PATCH] i6300esb: correctly convert watchdog clock ticks into nanoseconds, Laurent Vivier, 2015/08/03
[Qemu-devel] [PATCH][TRIVIAL] i6300esb: fix timer overflow, Laurent Vivier, 2015/08/04