1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __TRIGGER_H_ |
3 | #define __TRIGGER_H_ 1 |
4 | |
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_ON = 0, |
30 | TRIGGER_READY = 1, |
31 | TRIGGER_HIT = 2, |
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_ON; |
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 |
96 | |