diff options
author | Grant Likely <grant.likely@secretlab.ca> | 2010-05-22 02:36:56 -0400 |
---|---|---|
committer | Grant Likely <grant.likely@secretlab.ca> | 2010-05-22 02:36:56 -0400 |
commit | cf9b59e9d3e008591d1f54830f570982bb307a0d (patch) | |
tree | 113478ce8fd8c832ba726ffdf59b82cb46356476 /kernel/time/clocksource.c | |
parent | 44504b2bebf8b5823c59484e73096a7d6574471d (diff) | |
parent | f4b87dee923342505e1ddba8d34ce9de33e75050 (diff) |
Merge remote branch 'origin' into secretlab/next-devicetree
Merging in current state of Linus' tree to deal with merge conflicts and
build failures in vio.c after merge.
Conflicts:
drivers/i2c/busses/i2c-cpm.c
drivers/i2c/busses/i2c-mpc.c
drivers/net/gianfar.c
Also fixed up one line in arch/powerpc/kernel/vio.c to use the
correct node pointer.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'kernel/time/clocksource.c')
-rw-r--r-- | kernel/time/clocksource.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 1f5dde637457..f08e99c1d561 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c | |||
@@ -625,6 +625,54 @@ static void clocksource_enqueue(struct clocksource *cs) | |||
625 | list_add(&cs->list, entry); | 625 | list_add(&cs->list, entry); |
626 | } | 626 | } |
627 | 627 | ||
628 | |||
629 | /* | ||
630 | * Maximum time we expect to go between ticks. This includes idle | ||
631 | * tickless time. It provides the trade off between selecting a | ||
632 | * mult/shift pair that is very precise but can only handle a short | ||
633 | * period of time, vs. a mult/shift pair that can handle long periods | ||
634 | * of time but isn't as precise. | ||
635 | * | ||
636 | * This is a subsystem constant, and actual hardware limitations | ||
637 | * may override it (ie: clocksources that wrap every 3 seconds). | ||
638 | */ | ||
639 | #define MAX_UPDATE_LENGTH 5 /* Seconds */ | ||
640 | |||
641 | /** | ||
642 | * __clocksource_register_scale - Used to install new clocksources | ||
643 | * @t: clocksource to be registered | ||
644 | * @scale: Scale factor multiplied against freq to get clocksource hz | ||
645 | * @freq: clocksource frequency (cycles per second) divided by scale | ||
646 | * | ||
647 | * Returns -EBUSY if registration fails, zero otherwise. | ||
648 | * | ||
649 | * This *SHOULD NOT* be called directly! Please use the | ||
650 | * clocksource_register_hz() or clocksource_register_khz helper functions. | ||
651 | */ | ||
652 | int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) | ||
653 | { | ||
654 | |||
655 | /* | ||
656 | * Ideally we want to use some of the limits used in | ||
657 | * clocksource_max_deferment, to provide a more informed | ||
658 | * MAX_UPDATE_LENGTH. But for now this just gets the | ||
659 | * register interface working properly. | ||
660 | */ | ||
661 | clocks_calc_mult_shift(&cs->mult, &cs->shift, freq, | ||
662 | NSEC_PER_SEC/scale, | ||
663 | MAX_UPDATE_LENGTH*scale); | ||
664 | cs->max_idle_ns = clocksource_max_deferment(cs); | ||
665 | |||
666 | mutex_lock(&clocksource_mutex); | ||
667 | clocksource_enqueue(cs); | ||
668 | clocksource_select(); | ||
669 | clocksource_enqueue_watchdog(cs); | ||
670 | mutex_unlock(&clocksource_mutex); | ||
671 | return 0; | ||
672 | } | ||
673 | EXPORT_SYMBOL_GPL(__clocksource_register_scale); | ||
674 | |||
675 | |||
628 | /** | 676 | /** |
629 | * clocksource_register - Used to install new clocksources | 677 | * clocksource_register - Used to install new clocksources |
630 | * @t: clocksource to be registered | 678 | * @t: clocksource to be registered |