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Do calculations to estimate cpu and pclock using 64-bit and doing all

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the multiplications first.  Round to nearest, instead of down.

When estimating pclock don't compute sh_clock.cpucycle_1us * 1000000
sh_clock.cpuclock is exactly that (but without rounding errors).

This improves timekeeping on my Jornada.
This commit is contained in:
uwe 2006-10-11 02:31:19 +00:00
parent f6a0f2334c
commit 61a805fc2c
1 changed files with 12 additions and 6 deletions
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18
sys/arch/sh3/sh3/clock.c
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@ -1,4 +1,4 @@
/* $NetBSD: clock.c,v 1.34 2006/09/24 00:34:23 tsutsui Exp $ */
/* $NetBSD: clock.c,v 1.35 2006/10/11 02:31:19 uwe Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.34 2006/09/24 00:34:23 tsutsui Exp $");
__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.35 2006/10/11 02:31:19 uwe Exp $");
#include "opt_pclock.h"
#include "opt_hz.h"
@ -111,12 +111,14 @@ do { \
_reg_write_4(SH_(TCNT ## x), 0xffffffff); \
_reg_bset_1(SH_(TSTR), TSTR_STR##x); \
} while (/*CONSTCOND*/0)
#define TMU_ELAPSED(x) \
(0xffffffff - _reg_read_4(SH_(TCNT ## x)))
void
sh_clock_init(int flags)
{
uint32_t s, t0, t1 __attribute__((__unused__));
uint32_t s, t0;
sh_clock.flags = flags;
@ -155,7 +157,8 @@ sh_clock_init(int flags)
t0 = TMU_ELAPSED(0);
_cpu_exception_resume(s);
sh_clock.cpuclock = ((10000000 * 10) / t0) * sh_clock.tmuclk;
sh_clock.cpuclock
= ((uint64_t)sh_clock.tmuclk * 10000000 * 10 + t0/2) / t0;
sh_clock.cpucycle_1us = (sh_clock.tmuclk * 10) / t0;
if (CPU_IS_SH4)
@ -165,18 +168,21 @@ sh_clock_init(int flags)
* Estimate PCLOCK
*/
if (sh_clock.pclock == 0) {
uint32_t t1;
/* set TMU channel 1 source to PCLOCK / 4 */
_reg_write_2(SH_(TCR1), TCR_TPSC_P4);
s = _cpu_exception_suspend();
_cpu_spin(1); /* load function on cache. */
TMU_START(0);
TMU_START(1);
_cpu_spin(sh_clock.cpucycle_1us * 1000000); /* 1 sec. */
_cpu_spin(sh_clock.cpuclock); /* 1 sec. */
t0 = TMU_ELAPSED(0);
t1 = TMU_ELAPSED(1);
_cpu_exception_resume(s);
sh_clock.pclock = ((t1 * 4)/ t0) * SH_RTC_CLOCK;
sh_clock.pclock
= ((uint64_t)t1 * 4 * SH_RTC_CLOCK + t0/2) / t0;
}
/* Stop all counter */