Emulation/switch-linux
1
0
Fork 0
mirror of https://github.com/fail0verflow/switch-linux.git synced 2025-05-04 02:34:21 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

clockevents: Add direct ktime programming function

Browse source 
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@de.ibm.com>
Cc: john stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/20110823133142.815350967@de.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Martin Schwidefsky 2011-08-23 15:29:43 +02:00 • committed by Thomas Gleixner
parent d1748302f7
commit 65516f8a7c
2 changed files with 11 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
include/linux/clockchips.h
View file

@ -45,20 +45,22 @@ enum clock_event_nofitiers {
*/ */
#define CLOCK_EVT_FEAT_PERIODIC 0x000001 #define CLOCK_EVT_FEAT_PERIODIC 0x000001
#define CLOCK_EVT_FEAT_ONESHOT 0x000002 #define CLOCK_EVT_FEAT_ONESHOT 0x000002
#define CLOCK_EVT_FEAT_KTIME 0x000004
/* /*
* x86(64) specific misfeatures: * x86(64) specific misfeatures:
* *
* - Clockevent source stops in C3 State and needs broadcast support. * - Clockevent source stops in C3 State and needs broadcast support.
* - Local APIC timer is used as a dummy device. * - Local APIC timer is used as a dummy device.
*/ */
#define CLOCK_EVT_FEAT_C3STOP 0x000004 #define CLOCK_EVT_FEAT_C3STOP 0x000008
#define CLOCK_EVT_FEAT_DUMMY 0x000008 #define CLOCK_EVT_FEAT_DUMMY 0x000010
/** /**
* struct clock_event_device - clock event device descriptor * struct clock_event_device - clock event device descriptor
* @event_handler: Assigned by the framework to be called by the low * @event_handler: Assigned by the framework to be called by the low
* level handler of the event source * 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 * @next_event: local storage for the next event in oneshot mode
* @max_delta_ns: maximum delta value in ns * @max_delta_ns: maximum delta value in ns
* @min_delta_ns: minimum delta value in ns * @min_delta_ns: minimum delta value in ns
@ -81,6 +83,8 @@ struct clock_event_device {
void (*event_handler)(struct clock_event_device *); void (*event_handler)(struct clock_event_device *);
int (*set_next_event)(unsigned long evt, int (*set_next_event)(unsigned long evt,
struct clock_event_device *); struct clock_event_device *);
int (*set_next_ktime)(ktime_t expires,
struct clock_event_device *);
ktime_t next_event; ktime_t next_event;
u64 max_delta_ns; u64 max_delta_ns;
u64 min_delta_ns; u64 min_delta_ns;

4
kernel/time/clockevents.c
View file

@ -216,6 +216,10 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN) if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
return 0; 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())); delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
if (delta <= 0) if (delta <= 0)
return force ? clockevents_program_min_delta(dev) : -ETIME; return force ? clockevents_program_min_delta(dev) : -ETIME;