[MIPS] time: Make c0_compare_int_usable faster
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>
diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c
index 7274fd2..a59f67f 100644
--- a/arch/mips/kernel/cevt-r4k.c
+++ b/arch/mips/kernel/cevt-r4k.c
@@ -179,7 +179,7 @@
static int c0_compare_int_usable(void)
{
- const unsigned int delta = 0x300000;
+ unsigned int delta;
unsigned int cnt;
/*
@@ -192,9 +192,15 @@
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 */