96 lines
2 KiB
C
96 lines
2 KiB
C
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#ifndef __TRIGGER_H_
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#define __TRIGGER_H_ 1
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#include "util/debug.h"
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#include "asm/bug.h"
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/*
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* Use trigger to model operations which need to be executed when
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* an event (a signal, for example) is observed.
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*
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* States and transits:
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*
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*
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* OFF--> ON --> READY --(hit)--> HIT
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* ^ |
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* | (ready)
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* | |
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* \_____________/
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*
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* is_hit and is_ready are two key functions to query the state of
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* a trigger. is_hit means the event already happen; is_ready means the
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* trigger is waiting for the event.
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*/
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struct trigger {
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volatile enum {
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TRIGGER_ERROR = -2,
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TRIGGER_OFF = -1,
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TRIGGER_ON = 0,
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TRIGGER_READY = 1,
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TRIGGER_HIT = 2,
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} state;
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const char *name;
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};
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#define TRIGGER_WARN_ONCE(t, exp) \
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WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \
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t->name, t->state, __func__)
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static inline bool trigger_is_available(struct trigger *t)
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{
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return t->state >= 0;
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}
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static inline bool trigger_is_error(struct trigger *t)
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{
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return t->state <= TRIGGER_ERROR;
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}
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static inline void trigger_on(struct trigger *t)
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{
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TRIGGER_WARN_ONCE(t, TRIGGER_OFF);
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t->state = TRIGGER_ON;
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}
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static inline void trigger_ready(struct trigger *t)
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{
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if (!trigger_is_available(t))
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return;
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t->state = TRIGGER_READY;
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}
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static inline void trigger_hit(struct trigger *t)
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{
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if (!trigger_is_available(t))
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return;
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TRIGGER_WARN_ONCE(t, TRIGGER_READY);
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t->state = TRIGGER_HIT;
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}
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static inline void trigger_off(struct trigger *t)
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{
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if (!trigger_is_available(t))
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return;
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t->state = TRIGGER_OFF;
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}
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static inline void trigger_error(struct trigger *t)
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{
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t->state = TRIGGER_ERROR;
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}
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static inline bool trigger_is_ready(struct trigger *t)
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{
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return t->state == TRIGGER_READY;
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}
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static inline bool trigger_is_hit(struct trigger *t)
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{
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return t->state == TRIGGER_HIT;
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}
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#define DEFINE_TRIGGER(n) \
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struct trigger n = {.state = TRIGGER_OFF, .name = #n}
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#endif
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