| 1 | --- a/arch/mips/kernel/cevt-r4k.c |
| 2 | +++ b/arch/mips/kernel/cevt-r4k.c |
| 3 | @@ -21,6 +21,22 @@ |
| 4 | |
| 5 | #ifndef CONFIG_MIPS_MT_SMTC |
| 6 | |
| 7 | +/* |
| 8 | + * Compare interrupt can be routed and latched outside the core, |
| 9 | + * so a single execution hazard barrier may not be enough to give |
| 10 | + * it time to clear as seen in the Cause register. 4 time the |
| 11 | + * pipeline depth seems reasonably conservative, and empirically |
| 12 | + * works better in configurations with high CPU/bus clock ratios. |
| 13 | + */ |
| 14 | + |
| 15 | +#define compare_change_hazard() \ |
| 16 | + do { \ |
| 17 | + irq_disable_hazard(); \ |
| 18 | + irq_disable_hazard(); \ |
| 19 | + irq_disable_hazard(); \ |
| 20 | + irq_disable_hazard(); \ |
| 21 | + } while (0) |
| 22 | + |
| 23 | static int mips_next_event(unsigned long delta, |
| 24 | struct clock_event_device *evt) |
| 25 | { |
| 26 | @@ -30,6 +46,7 @@ static int mips_next_event(unsigned long |
| 27 | cnt = read_c0_count(); |
| 28 | cnt += delta; |
| 29 | write_c0_compare(cnt); |
| 30 | + compare_change_hazard(); |
| 31 | res = ((int)(read_c0_count() - cnt) > 0) ? -ETIME : 0; |
| 32 | return res; |
| 33 | } |
| 34 | |
