Module Name: src
Committed By: snj
Date: Wed Sep 16 04:46:14 UTC 2009
Modified Files:
src/sys/arch/vax/vax [netbsd-5]: clock.c
Log Message:
Pull up following revision(s) (requested by mhitch in ticket #955):
sys/arch/vax/vax/clock.c: revision 1.51 via patch
Not understanding what vax_mfpr_get_counter() was doing, my fix for
backwards time was incorrect, and actually disabled the use of mfpr for
timecounters. The intent was to emulate a 32 bit counter using the
hardclock_ticks from the clock interrupt and the contents of the
Interval Counter register. The problem with that was when the ICR
wrapped, but the clock interrupt was blocked resulted in an incorrect
count. Work around this by keeping track of the previous ICR value
and hardclock_ticks to ensure the 32 bit counter doesn't go backwards.
Also, the ICR runs from -10000 to -1, so adjust the value when reading it.
Now mfpr works quit nicely on my 4000/90.
To generate a diff of this commit:
cvs rdiff -u -r1.49 -r1.49.20.1 src/sys/arch/vax/vax/clock.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/vax/vax/clock.c
diff -u src/sys/arch/vax/vax/clock.c:1.49 src/sys/arch/vax/vax/clock.c:1.49.20.1
--- src/sys/arch/vax/vax/clock.c:1.49 Mon Jan 7 16:40:17 2008
+++ src/sys/arch/vax/vax/clock.c Wed Sep 16 04:46:14 2009
@@ -1,4 +1,4 @@
-/* $NetBSD: clock.c,v 1.49 2008/01/07 16:40:17 joerg Exp $ */
+/* $NetBSD: clock.c,v 1.49.20.1 2009/09/16 04:46:14 snj Exp $ */
/*
* Copyright (c) 1995 Ludd, University of Lule}, Sweden.
* All rights reserved.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.49 2008/01/07 16:40:17 joerg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.49.20.1 2009/09/16 04:46:14 snj Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -83,13 +83,31 @@
{
int cur_hardclock;
u_int counter;
+ static int prev_count, prev_hardclock;
do {
cur_hardclock = hardclock_ticks;
- counter = mfpr(PR_ICR);
+ counter = mfpr(PR_ICR) + tick;
} while (cur_hardclock != hardclock_ticks);
- return counter + hardclock_ticks * tick;
+ /*
+ * Handle interval counter wrapping with interrupts blocked.
+ * If the current hardclock_ticks is less than what we saw
+ * previously, use the previous value.
+ * If the interval counter is smaller, assume it has wrapped,
+ * and if the [adjusted] current hardclock ticks is the same
+ * as what we saw previously, increment the local copy of
+ * the hardclock ticks.
+ */
+ if (cur_hardclock < prev_hardclock)
+ cur_hardclock = prev_hardclock;
+ if (counter < prev_count && cur_hardclock == prev_hardclock)
+ cur_hardclock++;
+
+ prev_count = counter;
+ prev_hardclock=cur_hardclock;
+
+ return counter + cur_hardclock * tick;
}
#if VAX46 || VAXANY
