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95 lines
2.0 KiB
95 lines
2.0 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef __TRIGGER_H_ |
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#define __TRIGGER_H_ 1 |
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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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