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/*
* Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef PUBSUB_H
#define PUBSUB_H
#ifdef __LINKER__
/* For the linker ... */
#define __pubsub_start_sym(event) __pubsub_##event##_start
#define __pubsub_end_sym(event) __pubsub_##event##_end
#define __pubsub_section(event) __pubsub_##event
/*
* REGISTER_PUBSUB_EVENT has a different definition between linker and compiler
* contexts. In linker context, this collects pubsub sections for each event,
* placing guard symbols around each.
*/
#if defined(USE_ARM_LINK)
#define REGISTER_PUBSUB_EVENT(event) \
__pubsub_start_sym(event) +0 FIXED \
{ \
*(__pubsub_section(event)) \
} \
__pubsub_end_sym(event) +0 FIXED EMPTY 0 \
{ \
/* placeholder */ \
}
#else
#define REGISTER_PUBSUB_EVENT(event) \
__pubsub_start_sym(event) = .; \
KEEP(*(__pubsub_section(event))); \
__pubsub_end_sym(event) = .
#endif
#else /* __LINKER__ */
/* For the compiler ... */
#include <assert.h>
#include <cdefs.h>
#include <stddef.h>
#include <arch_helpers.h>
#if defined(USE_ARM_LINK)
#define __pubsub_start_sym(event) Load$$__pubsub_##event##_start$$Base
#define __pubsub_end_sym(event) Load$$__pubsub_##event##_end$$Base
#else
#define __pubsub_start_sym(event) __pubsub_##event##_start
#define __pubsub_end_sym(event) __pubsub_##event##_end
#endif
#define __pubsub_section(event) __section("__pubsub_" #event)
/*
* In compiler context, REGISTER_PUBSUB_EVENT declares the per-event symbols
* exported by the linker required for the other pubsub macros to work.
*/
#define REGISTER_PUBSUB_EVENT(event) \
extern pubsub_cb_t __pubsub_start_sym(event)[]; \
extern pubsub_cb_t __pubsub_end_sym(event)[]
/*
* Have the function func called back when the specified event happens. This
* macro places the function address into the pubsub section, which is picked up
* and invoked by the invoke_pubsubs() function via the PUBLISH_EVENT* macros.
*
* The extern declaration is there to satisfy MISRA C-2012 rule 8.4.
*/
#define SUBSCRIBE_TO_EVENT(event, func) \
extern pubsub_cb_t __cb_func_##func##event __pubsub_section(event); \
pubsub_cb_t __cb_func_##func##event __pubsub_section(event) = (func)
/*
* Iterate over subscribed handlers for a defined event. 'event' is the name of
* the event, and 'subscriber' a local variable of type 'pubsub_cb_t *'.
*/
#define for_each_subscriber(event, subscriber) \
for (subscriber = __pubsub_start_sym(event); \
subscriber < __pubsub_end_sym(event); \
subscriber++)
/*
* Publish a defined event supplying an argument. All subscribed handlers are
* invoked, but the return value of handlers are ignored for now.
*/
#define PUBLISH_EVENT_ARG(event, arg) \
do { \
pubsub_cb_t *subscriber; \
for_each_subscriber(event, subscriber) { \
(*subscriber)(arg); \
} \
} while (0)
/* Publish a defined event with NULL argument */
#define PUBLISH_EVENT(event) PUBLISH_EVENT_ARG(event, NULL)
/* Subscriber callback type */
typedef void* (*pubsub_cb_t)(const void *arg);
#endif /* __LINKER__ */
#endif /* PUBSUB_H */
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