diff options
Diffstat (limited to 'arch/mips/kernel/cevt-r4k.c')
| -rw-r--r-- | arch/mips/kernel/cevt-r4k.c | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c index 98c5a97..e2d8e19 100644 --- a/arch/mips/kernel/cevt-r4k.c +++ b/arch/mips/kernel/cevt-r4k.c @@ -103,19 +103,10 @@ static int c0_compare_int_pending(void) /* * Compare interrupt can be routed and latched outside the core, - * so a single execution hazard barrier may not be enough to give - * it time to clear as seen in the Cause register. 4 time the - * pipeline depth seems reasonably conservative, and empirically - * works better in configurations with high CPU/bus clock ratios. + * so wait up to worst case number of cycle counter ticks for timer interrupt + * changes to propagate to the cause register. */ - -#define compare_change_hazard() \ - do { \ - irq_disable_hazard(); \ - irq_disable_hazard(); \ - irq_disable_hazard(); \ - irq_disable_hazard(); \ - } while (0) +#define COMPARE_INT_SEEN_TICKS 50 int c0_compare_int_usable(void) { @@ -126,8 +117,12 @@ int c0_compare_int_usable(void) * IP7 already pending? Try to clear it by acking the timer. */ if (c0_compare_int_pending()) { - write_c0_compare(read_c0_count()); - compare_change_hazard(); + cnt = read_c0_count(); + write_c0_compare(cnt); + back_to_back_c0_hazard(); + while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS)) + if (!c0_compare_int_pending()) + break; if (c0_compare_int_pending()) return 0; } @@ -136,7 +131,7 @@ int c0_compare_int_usable(void) cnt = read_c0_count(); cnt += delta; write_c0_compare(cnt); - compare_change_hazard(); + back_to_back_c0_hazard(); if ((int)(read_c0_count() - cnt) < 0) break; /* increase delta if the timer was already expired */ @@ -145,12 +140,17 @@ int c0_compare_int_usable(void) while ((int)(read_c0_count() - cnt) <= 0) ; /* Wait for expiry */ - compare_change_hazard(); + while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS)) + if (c0_compare_int_pending()) + break; if (!c0_compare_int_pending()) return 0; - - write_c0_compare(read_c0_count()); - compare_change_hazard(); + cnt = read_c0_count(); + write_c0_compare(cnt); + back_to_back_c0_hazard(); + while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS)) + if (!c0_compare_int_pending()) + break; if (c0_compare_int_pending()) return 0; |