From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> There is at least one architecture (s390) with a sane clockevent device that can be programmed with the equivalent of a ktime. No need to create a delta against the current time, the ktime can be used directly. A new clock device function 'set_next_ktime' is introduced that is called with the unmodified ktime for the timer if the clock event device has the CLOCK_EVT_FEAT_KTIME bit set. Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> --- include/linux/clockchips.h | 10 +++++++--- kernel/time/clockevents.c | 4 ++++ 2 files changed, 11 insertions(+), 3 deletions(-) Index: linux-clockevents/include/linux/clockchips.h =================================================================== --- linux-clockevents.orig/include/linux/clockchips.h 2011-08-23 15:15:59.159588700 +0200 +++ linux-clockevents/include/linux/clockchips.h 2011-08-23 15:16:02.327629024 +0200 @@ -45,20 +45,22 @@ */ #define CLOCK_EVT_FEAT_PERIODIC 0x000001 #define CLOCK_EVT_FEAT_ONESHOT 0x000002 +#define CLOCK_EVT_FEAT_KTIME 0x000004 /* * x86(64) specific misfeatures: * * - Clockevent source stops in C3 State and needs broadcast support. * - Local APIC timer is used as a dummy device. */ -#define CLOCK_EVT_FEAT_C3STOP 0x000004 -#define CLOCK_EVT_FEAT_DUMMY 0x000008 +#define CLOCK_EVT_FEAT_C3STOP 0x000008 +#define CLOCK_EVT_FEAT_DUMMY 0x000010 /** * struct clock_event_device - clock event device descriptor * @event_handler: Assigned by the framework to be called by the low * level handler of the event source - * @set_next_event: set next event function + * @set_next_event: set next event function using a clocksource delta + * @set_next_ktime: set next event function using a direct ktime value * @next_event: local storage for the next event in oneshot mode * @max_delta_ns: maximum delta value in ns * @min_delta_ns: minimum delta value in ns @@ -81,6 +83,8 @@ void (*event_handler)(struct clock_event_device *); int (*set_next_event)(unsigned long evt, struct clock_event_device *); + int (*set_next_ktime)(ktime_t expires, + struct clock_event_device *); ktime_t next_event; u64 max_delta_ns; u64 min_delta_ns; Index: linux-clockevents/kernel/time/clockevents.c =================================================================== --- linux-clockevents.orig/kernel/time/clockevents.c 2011-08-23 15:15:59.159588700 +0200 +++ linux-clockevents/kernel/time/clockevents.c 2011-08-23 15:16:02.327629024 +0200 @@ -216,6 +216,10 @@ if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN) return 0; + /* Shortcut for clockevent devices that can deal with ktime. */ + if (dev->features & CLOCK_EVT_FEAT_KTIME) + return dev->set_next_ktime(expires, dev); + delta = ktime_to_ns(ktime_sub(expires, ktime_get())); if (delta <= 0) return force ? clockevents_program_min_delta(dev) : -ETIME; -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
