sambuc/atomthreads
1
0
Fork 0
mirror of https://github.com/kelvinlawson/atomthreads.git synced 2026-02-21 14:23:20 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity

atomtimer: Support timer callbacks registering new timers by walking the timer list, and building up a separate list of callbacks to be run later.

Browse Source
This commit is contained in:
Kelvin Lawson
2013-10-01 23:47:39 +01:00
parent 1b8681efa4
commit e3c90317a4
1 changed files with 46 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

57
kernel/atomtimer.c
View File

@@ -117,12 +117,6 @@ static void atomTimerDelayCallback (POINTER cb_data);
* through the time list, so the potential execution cycles cannot be
* determined in advance.
*
* Note that although the function can be called from interrupt context,
* it should not be called in the context of a timer callback interrupt.
* It modifies the internal timer list, and timer callbacks happen while
* walking the timer list, so you should not register a new timer in
* another timer's callback routine.
*
* @param[in] timer_ptr Pointer to timer descriptor
*
* @retval ATOM_OK Success
@@ -414,7 +408,8 @@ uint8_t atomTimerDelay (uint32_t ticks)
*/
static void atomTimerCallbacks (void)
{
ATOM_TIMER *prev_ptr, *next_ptr;
ATOM_TIMER *prev_ptr, *next_ptr, *saved_next_ptr;
ATOM_TIMER *callback_list_tail, *callback_list_head = NULL;
/*
* Walk the list decrementing each timer's remaining ticks count and
@@ -423,6 +418,9 @@ static void atomTimerCallbacks (void)
prev_ptr = next_ptr = timer_queue;
while (next_ptr)
{
/* Save the next timer in the list (we adjust next_ptr for callbacks) */
saved_next_ptr = next_ptr->next_timer;
/* Is this entry due? */
if (--(next_ptr->cb_ticks) == 0)
{
@@ -438,11 +436,28 @@ static void atomTimerCallbacks (void)
prev_ptr->next_timer = next_ptr->next_timer;
}
/* Call the registered callback */
if (next_ptr->cb_func)
/*
* Add this timer to the list of callbacks to run later when
* we've finished walking the list (we shouldn't call callbacks
* now in case they want to register new timers and hence walk
* the timer list.
*
* We reuse the ATOM_TIMER structure's next_ptr to maintain the
* callback list.
*/
if (callback_list_head == NULL)
{
next_ptr->cb_func (next_ptr->cb_data);
/* First callback request in the list */
callback_list_head = callback_list_tail = next_ptr;
}
else
{
/* Add callback request to the list tail */
callback_list_tail->next_timer = next_ptr;
}
/* Mark this timer as the end of the callback list */
next_ptr->next_timer = NULL;
/* Do not update prev_ptr, we have just removed this one */
@@ -459,8 +474,28 @@ static void atomTimerCallbacks (void)
}
/* Move on to the next in the list */
next_ptr = next_ptr->next_timer;
next_ptr = saved_next_ptr;
}
/*
* Check if any callbacks were due. We call them after we walk the list
* in case they want to register new timers (and hence walk the list).
*/
if (callback_list_head)
{
/* Walk the callback list */
next_ptr = callback_list_head;
while (next_ptr)
{
/* Call the registered callback */
if (next_ptr->cb_func)
{
next_ptr->cb_func (next_ptr->cb_data);
}
/* Move on to the next callback in the list */
next_ptr = next_ptr->next_timer;
}
}
}