98 lines
2.5 KiB
C
98 lines
2.5 KiB
C
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/****************************************************************************
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* Tick-based interval timers/one-shots - be mindful this is not really
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* intended for continuous timers but for events that need to run for a short
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* time and be cancelled without further software intervention.
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****************************************************************************/
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#include "config.h"
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#include "system.h" /* TIME_AFTER */
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#include "kernel.h"
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#include "timeout.h"
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#include "general.h"
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/* list of active timeout events */
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static struct timeout *tmo_list[MAX_NUM_TIMEOUTS+1];
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/* timeout tick task - calls event handlers when they expire
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* Event handlers may alter expiration, callback and data during operation.
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*/
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static void timeout_tick(void)
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{
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unsigned long tick = current_tick;
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struct timeout **p = tmo_list;
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struct timeout *curr;
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for(curr = *p; curr != NULL; curr = *(++p))
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{
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int ticks;
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if(TIME_BEFORE(tick, curr->expires))
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continue;
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/* this event has expired - call callback */
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ticks = curr->callback(curr);
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if(ticks > 0)
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{
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curr->expires = tick + ticks; /* reload */
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}
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else
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{
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timeout_cancel(curr); /* cancel */
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}
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}
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}
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/* Cancels a timeout callback - can be called from the ISR */
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void timeout_cancel(struct timeout *tmo)
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{
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int oldlevel = disable_irq_save();
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int rc = remove_array_ptr((void **)tmo_list, tmo);
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if(rc >= 0 && *tmo_list == NULL)
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{
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tick_remove_task(timeout_tick); /* Last one - remove task */
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}
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restore_irq(oldlevel);
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}
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/* Adds a timeout callback - calling with an active timeout resets the
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interval - can be called from the ISR */
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void timeout_register(struct timeout *tmo, timeout_cb_type callback,
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int ticks, intptr_t data)
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{
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int oldlevel;
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void **arr, **p;
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if(tmo == NULL)
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return;
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oldlevel = disable_irq_save();
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/* See if this one is already registered */
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arr = (void **)tmo_list;
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p = find_array_ptr(arr, tmo);
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if(p - arr < MAX_NUM_TIMEOUTS)
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{
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/* Vacancy */
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if(*p == NULL)
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{
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/* Not present */
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if(*tmo_list == NULL)
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{
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tick_add_task(timeout_tick); /* First one - add task */
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}
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*p = tmo;
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}
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tmo->callback = callback;
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tmo->data = data;
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tmo->expires = current_tick + ticks;
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}
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restore_irq(oldlevel);
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}
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