100 lines
2.7 KiB
C
100 lines
2.7 KiB
C
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/* main.c - Hello World demo */
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/*
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* Copyright (c) 2012-2014 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <zephyr.h>
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#include <misc/printk.h>
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/*
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* The hello world demo has two threads that utilize semaphores and sleeping
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* to take turns printing a greeting message at a controlled rate. The demo
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* shows both the static and dynamic approaches for spawning a thread; a real
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* world application would likely use the static approach for both threads.
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*/
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/* size of stack area used by each thread */
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#define STACKSIZE 1024
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/* scheduling priority used by each thread */
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#define PRIORITY 7
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/* delay between greetings (in ms) */
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#define SLEEPTIME 500
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/*
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* @param my_name thread identification string
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* @param my_sem thread's own semaphore
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* @param other_sem other thread's semaphore
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*/
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void helloLoop(const char *my_name,
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struct k_sem *my_sem, struct k_sem *other_sem)
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{
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while (1) {
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/* take my semaphore */
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k_sem_take(my_sem, K_FOREVER);
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/* say "hello" */
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printk("%s: Hello World from %s!\n", my_name, CONFIG_ARCH);
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/* wait a while, then let other thread have a turn */
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k_sleep(SLEEPTIME);
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k_sem_give(other_sem);
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}
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}
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/* define semaphores */
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K_SEM_DEFINE(threadA_sem, 1, 1); /* starts off "available" */
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K_SEM_DEFINE(threadB_sem, 0, 1); /* starts off "not available" */
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/* threadB is a dynamic thread that is spawned by threadA */
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void threadB(void *dummy1, void *dummy2, void *dummy3)
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{
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ARG_UNUSED(dummy1);
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ARG_UNUSED(dummy2);
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ARG_UNUSED(dummy3);
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/* invoke routine to ping-pong hello messages with threadA */
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helloLoop(__func__, &threadB_sem, &threadA_sem);
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}
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char __noinit __stack threadB_stack_area[STACKSIZE];
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/* threadA is a static thread that is spawned automatically */
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void threadA(void *dummy1, void *dummy2, void *dummy3)
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{
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ARG_UNUSED(dummy1);
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ARG_UNUSED(dummy2);
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ARG_UNUSED(dummy3);
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/* spawn threadB */
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k_thread_spawn(threadB_stack_area, STACKSIZE, threadB, NULL, NULL, NULL,
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PRIORITY, 0, K_NO_WAIT);
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/* invoke routine to ping-pong hello messages with threadB */
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helloLoop(__func__, &threadA_sem, &threadB_sem);
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}
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K_THREAD_DEFINE(threadA_id, STACKSIZE, threadA, NULL, NULL, NULL,
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PRIORITY, 0, K_NO_WAIT);
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