diff options
Diffstat (limited to 'drivers/char/hpet.c')
| -rw-r--r-- | drivers/char/hpet.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c index 32b8bbf5003e..340ba4f9dc54 100644 --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -72,7 +72,7 @@ static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ; #ifdef CONFIG_IA64 static void __iomem *hpet_mctr; -static cycle_t read_hpet(void) +static cycle_t read_hpet(struct clocksource *cs) { return (cycle_t)read_counter((void __iomem *)hpet_mctr); } @@ -713,7 +713,7 @@ static struct ctl_table_header *sysctl_header; */ #define TICK_CALIBRATE (1000UL) -static unsigned long hpet_calibrate(struct hpets *hpetp) +static unsigned long __hpet_calibrate(struct hpets *hpetp) { struct hpet_timer __iomem *timer = NULL; unsigned long t, m, count, i, flags, start; @@ -750,6 +750,26 @@ static unsigned long hpet_calibrate(struct hpets *hpetp) return (m - start) / i; } +static unsigned long hpet_calibrate(struct hpets *hpetp) +{ + unsigned long ret = -1; + unsigned long tmp; + + /* + * Try to calibrate until return value becomes stable small value. + * If SMI interruption occurs in calibration loop, the return value + * will be big. This avoids its impact. + */ + for ( ; ; ) { + tmp = __hpet_calibrate(hpetp); + if (ret <= tmp) + break; + ret = tmp; + } + + return ret; +} + int hpet_alloc(struct hpet_data *hdp) { u64 cap, mcfg; |