kernel/microkernel/k_event.c

/*
 * Copyright (c) 1997-2010, 2013-2014 Wind River Systems, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @file
 * @brief Event kernel services.
*/

#include <micro_private.h>
#include "microkernel/event.h"
#include <toolchain.h>
#include <sections.h>
#include <misc/__assert.h>

extern kevent_t _k_event_list_start[];
extern kevent_t _k_event_list_end[];

#define ASSERT_EVENT_IS_VALID(e, function) do { \
	__ASSERT((vaddr_t)e >= (vaddr_t)&_k_event_list_start,\
				"invalid event passed to %s", function); \
	__ASSERT((vaddr_t)e < (vaddr_t)&_k_event_list_end, \
				"invalid event passed to %s", function); \
} while ((0))

/**
 *
 * @brief Perform set event handler request
 *
 * @return N/A
 */
void _k_event_handler_set(struct k_args *A)
{
	struct _k_event_struct *E = (struct _k_event_struct *)A->args.e1.event;

	if (E->func != NULL) {
		if (likely(A->args.e1.func == NULL)) {
			/* uninstall handler */
			E->func = NULL;
			A->Time.rcode = RC_OK;
		} else {
			/* can't overwrite an existing handler */
			A->Time.rcode = RC_FAIL;
		}
	} else {
		/* install handler */
		E->func = A->args.e1.func;
		E->status = 0;
		A->Time.rcode = RC_OK;
	}
}

int task_event_handler_set(kevent_t event, kevent_handler_t handler)
{
	struct k_args A;

	ASSERT_EVENT_IS_VALID(event, __func__);

	A.Comm = _K_SVC_EVENT_HANDLER_SET;
	A.args.e1.event = event;
	A.args.e1.func = handler;
	KERNEL_ENTRY(&A);
	return A.Time.rcode;
}

/**
 *
 * @brief Finish handling a test for event request that timed out
 *
 * @return N/A
 */
void _k_event_test_timeout(struct k_args *A)
{
	struct _k_event_struct *E = (struct _k_event_struct *)A->args.e1.event;

	FREETIMER(A->Time.timer);
	A->Time.rcode = RC_TIME;
	E->waiter = NULL;
	_k_state_bit_reset(A->Ctxt.task, TF_EVNT);
}

/**
 *
 * @brief Perform test for event request
 *
 * @return N/A
 */
void _k_event_test(struct k_args *A)
{
	struct _k_event_struct *E = (struct _k_event_struct *)A->args.e1.event;

	if (E->status) { /* the next event can be received */
		E->status = 0;
		A->Time.rcode = RC_OK;
	} else {
		if (likely(A->Time.ticks != TICKS_NONE)) {
			/* Caller will wait for the event */
			if (likely(E->waiter == NULL)) {
				A->Ctxt.task = _k_current_task;
				E->waiter = A;
				_k_state_bit_set(_k_current_task, TF_EVNT);
#ifdef CONFIG_SYS_CLOCK_EXISTS
				if (A->Time.ticks == TICKS_UNLIMITED) {
					A->Time.timer = NULL;
				} else {
					A->Comm = _K_SVC_EVENT_TEST_TIMEOUT;
					_k_timeout_alloc(A);
				}
#endif
			} else {
				/* already a waiter present */
				A->Time.rcode = RC_FAIL;
			}
		} else {
			/* Caller will not wait for the event */
			A->Time.rcode = RC_FAIL;
		}
	}
}

int task_event_recv(kevent_t event, int32_t timeout)
{
	struct k_args A;

	ASSERT_EVENT_IS_VALID(event, __func__);

	A.Comm = _K_SVC_EVENT_TEST;
	A.args.e1.event = event;
	A.Time.ticks = timeout;
	KERNEL_ENTRY(&A);
	return A.Time.rcode;
}

/**
 *
 * @brief Signal an event
 *
 * Lowest level event signalling routine, which is invoked directly when the
 * signal is issued by a task and indirectly when the signal is issued by a
 * fiber or ISR. The specified event number must be valid.
 *
 * @return N/A
 */
void _k_do_event_signal(kevent_t event)
{
	struct _k_event_struct *E = (struct _k_event_struct *)event;
	struct k_args *A = E->waiter;
	int ret_val = 1; /* If no handler is available, then ret_val is 1 by default */

	if ((E->func) != NULL) { /* handler available */
		ret_val = (E->func)(event); /* call handler */
	}

	if (ret_val != 0) {
		E->status = 1;
	}
	/* if task waiting, will be rescheduled */
	if (((A) != NULL) && (E->status != 0)) {
#ifdef CONFIG_SYS_CLOCK_EXISTS
		if (A->Time.timer != NULL) {
			_k_timeout_free(A->Time.timer);
			A->Comm = _K_SVC_NOP;
		}
#endif
		A->Time.rcode = RC_OK;

		_k_state_bit_reset(A->Ctxt.task, TF_EVNT);
		E->waiter = NULL;
		E->status = 0;
	}

#ifdef CONFIG_OBJECT_MONITOR
	E->count++;
#endif
}

/**
 *
 * @brief Perform signal an event request
 *
 * @return N/A
 */
void _k_event_signal(struct k_args *A)
{
	kevent_t event = A->args.e1.event;

	_k_do_event_signal(event);
	A->Time.rcode = RC_OK;
}

int task_event_send(kevent_t event)
{
	struct k_args A;

	ASSERT_EVENT_IS_VALID(event, __func__);

	A.Comm = _K_SVC_EVENT_SIGNAL;
	A.args.e1.event = event;
	KERNEL_ENTRY(&A);
	return A.Time.rcode;
}

FUNC_ALIAS(isr_event_send, fiber_event_send, void);

void isr_event_send(kevent_t event)
{
	ASSERT_EVENT_IS_VALID(event, __func__);

	_COMMAND_STACK_SIZE_CHECK();

	nano_isr_stack_push(&_k_command_stack,
			    (uint32_t)event | KERNEL_CMD_EVENT_TYPE);
}