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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 |