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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
3dcc4436 WN |
2 | #ifndef __TRIGGER_H_ |
3 | #define __TRIGGER_H_ 1 | |
4 | ||
5 | #include "util/debug.h" | |
6 | #include "asm/bug.h" | |
7 | ||
8 | /* | |
9 | * Use trigger to model operations which need to be executed when | |
10 | * an event (a signal, for example) is observed. | |
11 | * | |
12 | * States and transits: | |
13 | * | |
14 | * | |
15 | * OFF--(on)--> READY --(hit)--> HIT | |
16 | * ^ | | |
17 | * | (ready) | |
18 | * | | | |
19 | * \_____________/ | |
20 | * | |
21 | * is_hit and is_ready are two key functions to query the state of | |
22 | * a trigger. is_hit means the event already happen; is_ready means the | |
23 | * trigger is waiting for the event. | |
24 | */ | |
25 | ||
26 | struct trigger { | |
27 | volatile enum { | |
28 | TRIGGER_ERROR = -2, | |
29 | TRIGGER_OFF = -1, | |
30 | TRIGGER_READY = 0, | |
31 | TRIGGER_HIT = 1, | |
32 | } state; | |
33 | const char *name; | |
34 | }; | |
35 | ||
36 | #define TRIGGER_WARN_ONCE(t, exp) \ | |
37 | WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \ | |
38 | t->name, t->state, __func__) | |
39 | ||
40 | static inline bool trigger_is_available(struct trigger *t) | |
41 | { | |
42 | return t->state >= 0; | |
43 | } | |
44 | ||
45 | static inline bool trigger_is_error(struct trigger *t) | |
46 | { | |
47 | return t->state <= TRIGGER_ERROR; | |
48 | } | |
49 | ||
50 | static inline void trigger_on(struct trigger *t) | |
51 | { | |
52 | TRIGGER_WARN_ONCE(t, TRIGGER_OFF); | |
53 | t->state = TRIGGER_READY; | |
54 | } | |
55 | ||
56 | static inline void trigger_ready(struct trigger *t) | |
57 | { | |
58 | if (!trigger_is_available(t)) | |
59 | return; | |
60 | t->state = TRIGGER_READY; | |
61 | } | |
62 | ||
63 | static inline void trigger_hit(struct trigger *t) | |
64 | { | |
65 | if (!trigger_is_available(t)) | |
66 | return; | |
67 | TRIGGER_WARN_ONCE(t, TRIGGER_READY); | |
68 | t->state = TRIGGER_HIT; | |
69 | } | |
70 | ||
71 | static inline void trigger_off(struct trigger *t) | |
72 | { | |
73 | if (!trigger_is_available(t)) | |
74 | return; | |
75 | t->state = TRIGGER_OFF; | |
76 | } | |
77 | ||
78 | static inline void trigger_error(struct trigger *t) | |
79 | { | |
80 | t->state = TRIGGER_ERROR; | |
81 | } | |
82 | ||
83 | static inline bool trigger_is_ready(struct trigger *t) | |
84 | { | |
85 | return t->state == TRIGGER_READY; | |
86 | } | |
87 | ||
88 | static inline bool trigger_is_hit(struct trigger *t) | |
89 | { | |
90 | return t->state == TRIGGER_HIT; | |
91 | } | |
92 | ||
93 | #define DEFINE_TRIGGER(n) \ | |
94 | struct trigger n = {.state = TRIGGER_OFF, .name = #n} | |
95 | #endif |