diff options
Diffstat (limited to 'drivers/char/hpet.c')
| -rw-r--r-- | drivers/char/hpet.c | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c index b619ca5eaf8c..a1eb14e6d9f7 100644 --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -78,7 +78,7 @@ struct hpets { struct hpet __iomem *hp_hpet; unsigned long hp_hpet_phys; struct time_interpolator *hp_interpolator; - unsigned long hp_period; + unsigned long long hp_tick_freq; unsigned long hp_delta; unsigned int hp_ntimer; unsigned int hp_which; @@ -427,12 +427,14 @@ static int hpet_ioctl_ieon(struct hpet_dev *devp) return 0; } -static inline unsigned long hpet_time_div(unsigned long dis) +/* converts Hz to number of timer ticks */ +static inline unsigned long hpet_time_div(struct hpets *hpets, + unsigned long dis) { - unsigned long long m = 1000000000000000ULL; + unsigned long long m; + m = hpets->hp_tick_freq + (dis >> 1); do_div(m, dis); - return (unsigned long)m; } @@ -480,7 +482,7 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel) { struct hpet_info info; - info.hi_ireqfreq = hpet_time_div(hpetp->hp_period * + info.hi_ireqfreq = hpet_time_div(hpetp, devp->hd_ireqfreq); info.hi_flags = readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK; @@ -524,7 +526,7 @@ hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel) break; } - devp->hd_ireqfreq = hpet_time_div(hpetp->hp_period * arg); + devp->hd_ireqfreq = hpet_time_div(hpetp, arg); } return err; @@ -713,7 +715,7 @@ static void hpet_register_interpolator(struct hpets *hpetp) ti->source = TIME_SOURCE_MMIO64; ti->shift = 10; ti->addr = &hpetp->hp_hpet->hpet_mc; - ti->frequency = hpet_time_div(hpets->hp_period); + ti->frequency = hpetp->hp_tick_freq; ti->drift = HPET_DRIFT; ti->mask = -1; @@ -750,7 +752,7 @@ static unsigned long hpet_calibrate(struct hpets *hpetp) t = read_counter(&timer->hpet_compare); i = 0; - count = hpet_time_div(hpetp->hp_period * TICK_CALIBRATE); + count = hpet_time_div(hpetp, TICK_CALIBRATE); local_irq_save(flags); @@ -775,7 +777,8 @@ int hpet_alloc(struct hpet_data *hdp) size_t siz; struct hpet __iomem *hpet; static struct hpets *last = (struct hpets *)0; - unsigned long ns; + unsigned long ns, period; + unsigned long long temp; /* * hpet_alloc can be called by platform dependent code. @@ -825,8 +828,12 @@ int hpet_alloc(struct hpet_data *hdp) last = hpetp; - hpetp->hp_period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >> - HPET_COUNTER_CLK_PERIOD_SHIFT; + period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >> + HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */ + temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */ + temp += period >> 1; /* round */ + do_div(temp, period); + hpetp->hp_tick_freq = temp; /* ticks per second */ printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s", hpetp->hp_which, hdp->hd_phys_address, @@ -835,8 +842,7 @@ int hpet_alloc(struct hpet_data *hdp) printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]); printk("\n"); - ns = hpetp->hp_period; /* femptoseconds, 10^-15 */ - ns /= 1000000; /* convert to nanoseconds, 10^-9 */ + ns = period / 1000000; /* convert to nanoseconds, 10^-9 */ printk(KERN_INFO "hpet%d: %ldns tick, %d %d-bit timers\n", hpetp->hp_which, ns, hpetp->hp_ntimer, cap & HPET_COUNTER_SIZE_MASK ? 64 : 32); |
