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[MIPS] time: Make c0_compare_int_usable faster

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Try increasingly longer time periods starting of at 0x10 cycles.  This
should be fast on hardware and work nicely with emulators.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Atsushi Nemoto 2007-10-23 21:55:42 +09:00 committed by Ralf Baechle
parent c637fecb4f
commit 3a6c43a787
1 changed files with 10 additions and 4 deletions
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14
arch/mips/kernel/cevt-r4k.c
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@ -179,7 +179,7 @@ static int c0_compare_int_pending(void)
static int c0_compare_int_usable(void)
{
const unsigned int delta = 0x300000;
unsigned int delta;
unsigned int cnt;
/*
@ -192,9 +192,15 @@ static int c0_compare_int_usable(void)
return 0;
}
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
for (delta = 0x10; delta <= 0x400000; delta <<= 1) {
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
irq_disable_hazard();
if ((int)(read_c0_count() - cnt) < 0)
break;
/* increase delta if the timer was already expired */
}
while ((int)(read_c0_count() - cnt) <= 0)
; /* Wait for expiry */