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Merge functionality of wakeups and semaphores-- fewer APIs and object types. semaphore_wait takes a timeout now so codecs and plugins have to be made incompatible. Don't make semaphores for targets not using them.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29492 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2011-03-02 08:49:38 +00:00
parent 05e180a130
commit 12375d1d3a
38 changed files with 294 additions and 311 deletions
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170
firmware/kernel.c
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@ -978,6 +978,9 @@ void mutex_unlock(struct mutex *m)
* Simple semaphore functions ;)
****************************************************************************/
#ifdef HAVE_SEMAPHORE_OBJECTS
/* Initialize the semaphore object.
* max = maximum up count the semaphore may assume (max >= 1)
* start = initial count of semaphore (0 <= count <= max) */
void semaphore_init(struct semaphore *s, int max, int start)
{
KERNEL_ASSERT(max > 0 && start >= 0 && start <= max,
@ -988,132 +991,97 @@ void semaphore_init(struct semaphore *s, int max, int start)
corelock_init(&s->cl);
}
void semaphore_wait(struct semaphore *s)
/* Down the semaphore's count or wait for 'timeout' ticks for it to go up if
* it is already 0. 'timeout' as TIMEOUT_NOBLOCK (0) will not block and may
* safely be used in an ISR. */
int semaphore_wait(struct semaphore *s, int timeout)
{
struct thread_entry *current;
int ret;
int oldlevel;
int count;
oldlevel = disable_irq_save();
corelock_lock(&s->cl);
if(LIKELY(--s->count >= 0))
count = s->count;
if(LIKELY(count > 0))
{
/* wait satisfied */
/* count is not zero; down it */
s->count = count - 1;
ret = OBJ_WAIT_SUCCEEDED;
}
else if(timeout == 0)
{
/* just polling it */
ret = OBJ_WAIT_TIMEDOUT;
}
else
{
/* too many waits - block until count is upped... */
struct thread_entry * current = thread_id_entry(THREAD_ID_CURRENT);
IF_COP( current->obj_cl = &s->cl; )
current->bqp = &s->queue;
/* return value will be OBJ_WAIT_SUCCEEDED after wait if wake was
* explicit in semaphore_release */
current->retval = OBJ_WAIT_TIMEDOUT;
if(timeout > 0)
block_thread_w_tmo(current, timeout); /* ...or timed out... */
else
block_thread(current); /* -timeout = infinite */
corelock_unlock(&s->cl);
return;
/* ...and turn control over to next thread */
switch_thread();
return current->retval;
}
/* too many waits - block until dequeued... */
current = thread_id_entry(THREAD_ID_CURRENT);
IF_COP( current->obj_cl = &s->cl; )
current->bqp = &s->queue;
disable_irq();
block_thread(current);
corelock_unlock(&s->cl);
restore_irq(oldlevel);
/* ...and turn control over to next thread */
switch_thread();
return ret;
}
/* Up the semaphore's count and release any thread waiting at the head of the
* queue. The count is saturated to the value of the 'max' parameter specified
* in 'semaphore_init'. */
void semaphore_release(struct semaphore *s)
{
IF_PRIO( unsigned int result = THREAD_NONE; )
int oldlevel;
oldlevel = disable_irq_save();
corelock_lock(&s->cl);
if(s->count < s->max && ++s->count <= 0)
if(LIKELY(s->queue != NULL))
{
/* there should be threads in this queue */
KERNEL_ASSERT(s->queue != NULL, "semaphore->wakeup\n");
/* a thread was queued - wake it up */
int oldlevel = disable_irq_save();
/* a thread was queued - wake it up and keep count at 0 */
KERNEL_ASSERT(s->count == 0,
"semaphore_release->threads queued but count=%d!\n", s->count);
s->queue->retval = OBJ_WAIT_SUCCEEDED; /* indicate explicit wake */
IF_PRIO( result = ) wakeup_thread(&s->queue);
restore_irq(oldlevel);
}
else
{
int count = s->count;
if(count < s->max)
{
/* nothing waiting - up it */
s->count = count + 1;
}
}
corelock_unlock(&s->cl);
restore_irq(oldlevel);
#ifdef HAVE_PRIORITY_SCHEDULING
if(result & THREAD_SWITCH)
#if defined(HAVE_PRIORITY_SCHEDULING) && defined(irq_enabled_checkval)
/* No thread switch if IRQ disabled - it's probably called via ISR.
* switch_thread would as well enable them anyway. */
if((result & THREAD_SWITCH) && irq_enabled_checkval(oldlevel))
switch_thread();
#endif
}
#endif /* HAVE_SEMAPHORE_OBJECTS */
#ifdef HAVE_WAKEUP_OBJECTS
/****************************************************************************
* Lightweight IRQ-compatible wakeup object
*/
/* Initialize the wakeup object */
void wakeup_init(struct wakeup *w)
{
w->queue = NULL;
w->signalled = false;
IF_COP( corelock_init(&w->cl); )
}
/* Wait for a signal blocking indefinitely or for a specified period */
int wakeup_wait(struct wakeup *w, int timeout)
{
int ret = OBJ_WAIT_SUCCEEDED; /* Presume success */
int oldlevel = disable_irq_save();
corelock_lock(&w->cl);
if(LIKELY(!w->signalled && timeout != TIMEOUT_NOBLOCK))
{
struct thread_entry * current = thread_id_entry(THREAD_ID_CURRENT);
IF_COP( current->obj_cl = &w->cl; )
current->bqp = &w->queue;
if (timeout != TIMEOUT_BLOCK)
block_thread_w_tmo(current, timeout);
else
block_thread(current);
corelock_unlock(&w->cl);
switch_thread();
oldlevel = disable_irq_save();
corelock_lock(&w->cl);
}
if(UNLIKELY(!w->signalled))
{
/* Timed-out or failed */
ret = (timeout != TIMEOUT_BLOCK) ?
OBJ_WAIT_TIMEDOUT : OBJ_WAIT_FAILED;
}
w->signalled = false; /* Reset */
corelock_unlock(&w->cl);
restore_irq(oldlevel);
return ret;
}
/* Signal the thread waiting or leave the signal if the thread hasn't
* waited yet.
*
* returns THREAD_NONE or THREAD_OK
*/
int wakeup_signal(struct wakeup *w)
{
int oldlevel = disable_irq_save();
int ret;
corelock_lock(&w->cl);
w->signalled = true;
ret = wakeup_thread(&w->queue);
corelock_unlock(&w->cl);
restore_irq(oldlevel);
return ret;
}
#endif /* HAVE_WAKEUP_OBJECTS */