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author | Sascha Hauer <s.hauer@pengutronix.de> | 2013-12-12 17:17:06 +0100 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2013-12-18 16:47:48 +0100 |
commit | 3c46c02c5423fe8799f5ebcd2a07cf995b620a48 (patch) | |
tree | 2ff6d718f4671fda7f265d6f2bafe7a8ae29bfc9 | |
parent | 8fc3a9382537a029f5630d15209beb2dc44d4acd (diff) | |
download | barebox-3c46c02c5423fe8799f5ebcd2a07cf995b620a48.tar.gz barebox-3c46c02c5423fe8799f5ebcd2a07cf995b620a48.tar.xz |
poller: Allow to call functions asynchronously
Sometimes execution of a function has to be delayed, for example
when a backlight can only be turned on when the picture has stabilized.
To help in such situations add a convenience function around the poller
stuff to call a function after a delay.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
-rw-r--r-- | common/poller.c | 58 | ||||
-rw-r--r-- | include/poller.h | 14 |
2 files changed, 71 insertions, 1 deletions
diff --git a/common/poller.c b/common/poller.c index 0583a532cf..496636d1d7 100644 --- a/common/poller.c +++ b/common/poller.c @@ -11,24 +11,82 @@ #include <module.h> #include <param.h> #include <poller.h> +#include <clock.h> static LIST_HEAD(poller_list); static int poller_active; int poller_register(struct poller_struct *poller) { + if (poller->registered) + return -EBUSY; + list_add_tail(&poller->list, &poller_list); + poller->registered = 1; return 0; } int poller_unregister(struct poller_struct *poller) { + if (!poller->registered) + return -ENODEV; + list_del(&poller->list); + poller->registered = 0; return 0; } +static void poller_async_callback(struct poller_struct *poller) +{ + struct poller_async *pa = container_of(poller, struct poller_async, poller); + + if (get_time_ns() < pa->end) + return; + + pa->fn(pa->ctx); + pa->fn = NULL; + poller_unregister(&pa->poller); +} + +/* + * Cancel an outstanding asynchronous function call + * + * @pa the poller that has been scheduled + * + * Cancel an outstanding function call. Returns 0 if the call + * has actually been cancelled or -ENODEV when the call wasn't + * scheduled. + * + */ +int poller_async_cancel(struct poller_async *pa) +{ + return poller_unregister(&pa->poller); +} + +/* + * Call a function asynchronously + * + * @pa the poller to be used + * @delay The delay in nanoseconds + * @fn The function to call + * @ctx context pointer passed to the function + * + * This calls the passed function after a delay of delay_ns. Returns + * a pointer which can be used as a cookie to cancel a scheduled call. + */ +int poller_call_async(struct poller_async *pa, uint64_t delay_ns, + void (*fn)(void *), void *ctx) +{ + pa->ctx = ctx; + pa->poller.func = poller_async_callback; + pa->end = get_time_ns() + delay_ns; + pa->fn = fn; + + return poller_register(&pa->poller); +} + void poller_call(void) { struct poller_struct *poller, *tmp; diff --git a/include/poller.h b/include/poller.h index dc981557db..cda5b5774b 100644 --- a/include/poller.h +++ b/include/poller.h @@ -12,13 +12,25 @@ struct poller_struct { void (*func)(struct poller_struct *poller); - + int registered; struct list_head list; }; int poller_register(struct poller_struct *poller); int poller_unregister(struct poller_struct *poller); +struct poller_async; + +struct poller_async { + struct poller_struct poller; + void (*fn)(void *); + void *ctx; + uint64_t end; +}; + +int poller_call_async(struct poller_async *pa, uint64_t delay_ns, + void (*fn)(void *), void *ctx); +int poller_async_cancel(struct poller_async *pa); #ifdef CONFIG_POLLER void poller_call(void); |