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Use the clock count register as a timecounter, as it's more accurate.

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This commit is contained in:
Olivier Houchard 2005-10-17 14:51:01 +00:00
parent 170c211c42
commit 3de553a473
1 changed files with 13 additions and 16 deletions
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29
sys/arm/xscale/i80321/i80321_timer.c
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@ -72,8 +72,6 @@ static unsigned i80321_timer_get_timecount(struct timecounter *tc);
static uint32_t counts_per_hz;
static uint32_t offset = 0;
static uint32_t last = -1;
static int ticked = 0;
#define COUNTS_PER_SEC 200000000 /* 200MHz */
@ -83,7 +81,7 @@ static struct timecounter i80321_timer_timecounter = {
i80321_timer_get_timecount, /* get_timecount */
NULL, /* no poll_pps */
~0u, /* counter_mask */
COUNTS_PER_SEC, /* frequency */
COUNTS_PER_SEC * 3, /* frequency */
"i80321 timer", /* name */
1000 /* quality */
};
@ -236,19 +234,11 @@ tisr_read(void)
static unsigned
i80321_timer_get_timecount(struct timecounter *tc)
{
uint32_t cur = tcr0_read();
if (cur > last && last != -1) {
offset += counts_per_hz;
if (ticked > 0)
ticked--;
}
if (ticked) {
offset += ticked * counts_per_hz;
ticked = 0;
}
last = cur;
return (counts_per_hz - cur + offset);
uint32_t ret;
__asm __volatile("mrc p14, 0, %0, c1, c0, 0\n"
: "=r" (ret));
return (ret);
}
/*
@ -329,6 +319,13 @@ cpu_initclocks(void)
tc_init(&i80321_timer_timecounter);
restore_interrupts(oldirqstate);
rid = 0;
/* Enable the clock count register. */
__asm __volatile("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (rid));
rid &= ~(1 << 3);
rid |= (1 << 2) | 1;
__asm __volatile("mcr p14, 0, %0, c0, c0, 0\n"
: : "r" (rid));
}