1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef __TRIGGER_H_
3*4882a593Smuzhiyun #define __TRIGGER_H_ 1
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun #include "asm/bug.h"
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun /*
8*4882a593Smuzhiyun * Use trigger to model operations which need to be executed when
9*4882a593Smuzhiyun * an event (a signal, for example) is observed.
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun * States and transits:
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun *
14*4882a593Smuzhiyun * OFF--> ON --> READY --(hit)--> HIT
15*4882a593Smuzhiyun * ^ |
16*4882a593Smuzhiyun * | (ready)
17*4882a593Smuzhiyun * | |
18*4882a593Smuzhiyun * \_____________/
19*4882a593Smuzhiyun *
20*4882a593Smuzhiyun * is_hit and is_ready are two key functions to query the state of
21*4882a593Smuzhiyun * a trigger. is_hit means the event already happen; is_ready means the
22*4882a593Smuzhiyun * trigger is waiting for the event.
23*4882a593Smuzhiyun */
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun struct trigger {
26*4882a593Smuzhiyun volatile enum {
27*4882a593Smuzhiyun TRIGGER_ERROR = -2,
28*4882a593Smuzhiyun TRIGGER_OFF = -1,
29*4882a593Smuzhiyun TRIGGER_ON = 0,
30*4882a593Smuzhiyun TRIGGER_READY = 1,
31*4882a593Smuzhiyun TRIGGER_HIT = 2,
32*4882a593Smuzhiyun } state;
33*4882a593Smuzhiyun const char *name;
34*4882a593Smuzhiyun };
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun #define TRIGGER_WARN_ONCE(t, exp) \
37*4882a593Smuzhiyun WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \
38*4882a593Smuzhiyun t->name, t->state, __func__)
39*4882a593Smuzhiyun
trigger_is_available(struct trigger * t)40*4882a593Smuzhiyun static inline bool trigger_is_available(struct trigger *t)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun return t->state >= 0;
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun
trigger_is_error(struct trigger * t)45*4882a593Smuzhiyun static inline bool trigger_is_error(struct trigger *t)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun return t->state <= TRIGGER_ERROR;
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun
trigger_on(struct trigger * t)50*4882a593Smuzhiyun static inline void trigger_on(struct trigger *t)
51*4882a593Smuzhiyun {
52*4882a593Smuzhiyun TRIGGER_WARN_ONCE(t, TRIGGER_OFF);
53*4882a593Smuzhiyun t->state = TRIGGER_ON;
54*4882a593Smuzhiyun }
55*4882a593Smuzhiyun
trigger_ready(struct trigger * t)56*4882a593Smuzhiyun static inline void trigger_ready(struct trigger *t)
57*4882a593Smuzhiyun {
58*4882a593Smuzhiyun if (!trigger_is_available(t))
59*4882a593Smuzhiyun return;
60*4882a593Smuzhiyun t->state = TRIGGER_READY;
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun
trigger_hit(struct trigger * t)63*4882a593Smuzhiyun static inline void trigger_hit(struct trigger *t)
64*4882a593Smuzhiyun {
65*4882a593Smuzhiyun if (!trigger_is_available(t))
66*4882a593Smuzhiyun return;
67*4882a593Smuzhiyun TRIGGER_WARN_ONCE(t, TRIGGER_READY);
68*4882a593Smuzhiyun t->state = TRIGGER_HIT;
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
trigger_off(struct trigger * t)71*4882a593Smuzhiyun static inline void trigger_off(struct trigger *t)
72*4882a593Smuzhiyun {
73*4882a593Smuzhiyun if (!trigger_is_available(t))
74*4882a593Smuzhiyun return;
75*4882a593Smuzhiyun t->state = TRIGGER_OFF;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
trigger_error(struct trigger * t)78*4882a593Smuzhiyun static inline void trigger_error(struct trigger *t)
79*4882a593Smuzhiyun {
80*4882a593Smuzhiyun t->state = TRIGGER_ERROR;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
trigger_is_ready(struct trigger * t)83*4882a593Smuzhiyun static inline bool trigger_is_ready(struct trigger *t)
84*4882a593Smuzhiyun {
85*4882a593Smuzhiyun return t->state == TRIGGER_READY;
86*4882a593Smuzhiyun }
87*4882a593Smuzhiyun
trigger_is_hit(struct trigger * t)88*4882a593Smuzhiyun static inline bool trigger_is_hit(struct trigger *t)
89*4882a593Smuzhiyun {
90*4882a593Smuzhiyun return t->state == TRIGGER_HIT;
91*4882a593Smuzhiyun }
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun #define DEFINE_TRIGGER(n) \
94*4882a593Smuzhiyun struct trigger n = {.state = TRIGGER_OFF, .name = #n}
95*4882a593Smuzhiyun #endif
96