swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Tip revision: f40ddce88593482919761f74910f42f4b84c004b authored by Linus Torvalds on 14 February 2021, 22:32:24 UTC
Linux 5.11
Linux 5.11
Tip revision: f40ddce
trigger.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __TRIGGER_H_
#define __TRIGGER_H_ 1
#include "asm/bug.h"
/*
* Use trigger to model operations which need to be executed when
* an event (a signal, for example) is observed.
*
* States and transits:
*
*
* OFF--> ON --> READY --(hit)--> HIT
* ^ |
* | (ready)
* | |
* \_____________/
*
* is_hit and is_ready are two key functions to query the state of
* a trigger. is_hit means the event already happen; is_ready means the
* trigger is waiting for the event.
*/
struct trigger {
volatile enum {
TRIGGER_ERROR = -2,
TRIGGER_OFF = -1,
TRIGGER_ON = 0,
TRIGGER_READY = 1,
TRIGGER_HIT = 2,
} state;
const char *name;
};
#define TRIGGER_WARN_ONCE(t, exp) \
WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \
t->name, t->state, __func__)
static inline bool trigger_is_available(struct trigger *t)
{
return t->state >= 0;
}
static inline bool trigger_is_error(struct trigger *t)
{
return t->state <= TRIGGER_ERROR;
}
static inline void trigger_on(struct trigger *t)
{
TRIGGER_WARN_ONCE(t, TRIGGER_OFF);
t->state = TRIGGER_ON;
}
static inline void trigger_ready(struct trigger *t)
{
if (!trigger_is_available(t))
return;
t->state = TRIGGER_READY;
}
static inline void trigger_hit(struct trigger *t)
{
if (!trigger_is_available(t))
return;
TRIGGER_WARN_ONCE(t, TRIGGER_READY);
t->state = TRIGGER_HIT;
}
static inline void trigger_off(struct trigger *t)
{
if (!trigger_is_available(t))
return;
t->state = TRIGGER_OFF;
}
static inline void trigger_error(struct trigger *t)
{
t->state = TRIGGER_ERROR;
}
static inline bool trigger_is_ready(struct trigger *t)
{
return t->state == TRIGGER_READY;
}
static inline bool trigger_is_hit(struct trigger *t)
{
return t->state == TRIGGER_HIT;
}
#define DEFINE_TRIGGER(n) \
struct trigger n = {.state = TRIGGER_OFF, .name = #n}
#endif