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/*
* Copyright (c) 2018, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef __EVENTS_H__
#define __EVENTS_H__
#include <spinlock.h>
typedef struct {
/*
* Counter that keeps track of the minimum number of recipients of the
* event. When the event is sent, this counter is incremented. When it
* is received, it is decremented. Therefore, a zero value means that
* the event hasn't been sent yet, or that all recipients have already
* received it.
*
* Volatile is needed as it will enforce ordering relatively to
* accesses to the lock.
*/
volatile unsigned int cnt;
/* Lock used to avoid concurrent accesses to the counter */
spinlock_t lock;
} event_t;
/*
* Initialise an event.
* event: Address of the event to initialise
*
* This function can be used either to initialise a newly created event
* structure or to recycle one.
*
* Note: This function is not MP-safe. It can't use the event lock as it is
* responsible for initialising it. Care must be taken to ensure this function
* is called in the right circumstances.
*/
void tftf_init_event(event_t *event);
/*
* Send an event to a CPU.
* event: Address of the variable that acts as a synchronisation object.
*
* Which CPU receives the event is determined on a first-come, first-served
* basis. If several CPUs are waiting for the same event then the first CPU
* which takes the event will reflect that in the event structure.
*
* Note: This is equivalent to calling:
* tftf_send_event_to(event, 1);
*/
void tftf_send_event(event_t *event);
/*
* Send an event to all CPUs.
* event: Address of the variable that acts as a synchronisation object.
*
* Note: This is equivalent to calling:
* tftf_send_event_to(event, PLATFORM_CORE_COUNT);
*/
void tftf_send_event_to_all(event_t *event);
/*
* Send an event to a given number of CPUs.
* event: Address of the variable that acts as a synchronisation object.
* cpus_count: Number of CPUs to send the event to.
*
* Which CPUs receive the event is determined on a first-come, first-served
* basis. If more than 'cpus_count' CPUs are waiting for the same event then the
* first 'cpus_count' CPUs which take the event will reflect that in the event
* structure.
*/
void tftf_send_event_to(event_t *event, unsigned int cpus_count);
/*
* Wait for an event.
* event: Address of the variable that acts as a synchronisation object.
*/
void tftf_wait_for_event(event_t *event);
#endif /* __EVENTS_H__ */
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