projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 3dcc4436 WN |
1 | #ifndef __TRIGGER_H_ |
| 2 | #define __TRIGGER_H_ 1 | |
| 3 | ||
| 4 | #include "util/debug.h" | |
| 5 | #include "asm/bug.h" | |
| 6 | ||
| 7 | /* | |
| 8 | * Use trigger to model operations which need to be executed when | |
| 9 | * an event (a signal, for example) is observed. | |
| 10 | * | |
| 11 | * States and transits: | |
| 12 | * | |
| 13 | * | |
| 14 | * OFF--(on)--> READY --(hit)--> HIT | |
| 15 | * ^ | | |
| 16 | * | (ready) | |
| 17 | * | | | |
| 18 | * \_____________/ | |
| 19 | * | |
| 20 | * is_hit and is_ready are two key functions to query the state of | |
| 21 | * a trigger. is_hit means the event already happen; is_ready means the | |
| 22 | * trigger is waiting for the event. | |
| 23 | */ | |
| 24 | ||
| 25 | struct trigger { | |
| 26 | volatile enum { | |
| 27 | TRIGGER_ERROR = -2, | |
| 28 | TRIGGER_OFF = -1, | |
| 29 | TRIGGER_READY = 0, | |
| 30 | TRIGGER_HIT = 1, | |
| 31 | } state; | |
| 32 | const char *name; | |
| 33 | }; | |
| 34 | ||
| 35 | #define TRIGGER_WARN_ONCE(t, exp) \ | |
| 36 | WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \ | |
| 37 | t->name, t->state, __func__) | |
| 38 | ||
| 39 | static inline bool trigger_is_available(struct trigger *t) | |
| 40 | { | |
| 41 | return t->state >= 0; | |
| 42 | } | |
| 43 | ||
| 44 | static inline bool trigger_is_error(struct trigger *t) | |
| 45 | { | |
| 46 | return t->state <= TRIGGER_ERROR; | |
| 47 | } | |
| 48 | ||
| 49 | static inline void trigger_on(struct trigger *t) | |
| 50 | { | |
| 51 | TRIGGER_WARN_ONCE(t, TRIGGER_OFF); | |
| 52 | t->state = TRIGGER_READY; | |
| 53 | } | |
| 54 | ||
| 55 | static inline void trigger_ready(struct trigger *t) | |
| 56 | { | |
| 57 | if (!trigger_is_available(t)) | |
| 58 | return; | |
| 59 | t->state = TRIGGER_READY; | |
| 60 | } | |
| 61 | ||
| 62 | static inline void trigger_hit(struct trigger *t) | |
| 63 | { | |
| 64 | if (!trigger_is_available(t)) | |
| 65 | return; | |
| 66 | TRIGGER_WARN_ONCE(t, TRIGGER_READY); | |
| 67 | t->state = TRIGGER_HIT; | |
| 68 | } | |
| 69 | ||
| 70 | static inline void trigger_off(struct trigger *t) | |
| 71 | { | |
| 72 | if (!trigger_is_available(t)) | |
| 73 | return; | |
| 74 | t->state = TRIGGER_OFF; | |
| 75 | } | |
| 76 | ||
| 77 | static inline void trigger_error(struct trigger *t) | |
| 78 | { | |
| 79 | t->state = TRIGGER_ERROR; | |
| 80 | } | |
| 81 | ||
| 82 | static inline bool trigger_is_ready(struct trigger *t) | |
| 83 | { | |
| 84 | return t->state == TRIGGER_READY; | |
| 85 | } | |
| 86 | ||
| 87 | static inline bool trigger_is_hit(struct trigger *t) | |
| 88 | { | |
| 89 | return t->state == TRIGGER_HIT; | |
| 90 | } | |
| 91 | ||
| 92 | #define DEFINE_TRIGGER(n) \ | |
| 93 | struct trigger n = {.state = TRIGGER_OFF, .name = #n} | |
| 94 | #endif |