1 /*
2 * Copyright (c) 2019 Intel Corporation
3 * Copyright (c) 2012-2014 Wind River Systems, Inc.
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #include <zephyr/kernel.h>
9 #include <zephyr/sys/printk.h>
10 #include <zephyr/logging/log.h>
11 #include <zephyr/usb/usb_device.h>
12 #include <zephyr/tracing/tracing.h>
13
14 /*
15 * The hello world demo has two threads that utilize semaphores and sleeping
16 * to take turns printing a greeting message at a controlled rate. The demo
17 * shows both the static and dynamic approaches for spawning a thread; a real
18 * world application would likely use the static approach for both threads.
19 */
20
21
22 /* size of stack area used by each thread */
23 #define STACKSIZE (2048)
24
25 /* scheduling priority used by each thread */
26 #define PRIORITY 7
27
28 /* delay between greetings (in ms) */
29 #define SLEEPTIME 500
30
31 static uint32_t counter;
32
33 /*
34 * @param my_name thread identification string
35 * @param my_sem thread's own semaphore
36 * @param other_sem other thread's semaphore
37 */
helloLoop(const char * my_name,struct k_sem * my_sem,struct k_sem * other_sem)38 void helloLoop(const char *my_name,
39 struct k_sem *my_sem, struct k_sem *other_sem)
40 {
41 const char *tname;
42
43 while (1) {
44 /* take my semaphore */
45 k_sem_take(my_sem, K_FOREVER);
46
47 /* Provide a named trace, with the counter value */
48 sys_trace_named_event("counter_value", counter, 0);
49 counter++;
50
51 /* say "hello" */
52 tname = k_thread_name_get(k_current_get());
53 if (tname == NULL) {
54 printk("%s: Hello World from %s!\n",
55 my_name, CONFIG_BOARD);
56 } else {
57 printk("%s: Hello World from %s!\n",
58 tname, CONFIG_BOARD);
59 }
60
61 /* wait a while, then let other thread have a turn */
62 k_msleep(SLEEPTIME);
63 k_sem_give(other_sem);
64 }
65 }
66
67 /* define semaphores */
68
69 K_SEM_DEFINE(threadA_sem, 1, 1); /* starts off "available" */
70 K_SEM_DEFINE(threadB_sem, 0, 1); /* starts off "not available" */
71
72
73 /* threadB is a dynamic thread that is spawned by threadA */
74
threadB(void * dummy1,void * dummy2,void * dummy3)75 void threadB(void *dummy1, void *dummy2, void *dummy3)
76 {
77 ARG_UNUSED(dummy1);
78 ARG_UNUSED(dummy2);
79 ARG_UNUSED(dummy3);
80
81 /* invoke routine to ping-pong hello messages with threadA */
82 helloLoop(__func__, &threadB_sem, &threadA_sem);
83 }
84
85 K_THREAD_STACK_DEFINE(threadB_stack_area, STACKSIZE);
86 static struct k_thread threadB_data;
87
88 /* threadA is a static thread that is spawned automatically */
89
threadA(void * dummy1,void * dummy2,void * dummy3)90 void threadA(void *dummy1, void *dummy2, void *dummy3)
91 {
92 ARG_UNUSED(dummy1);
93 ARG_UNUSED(dummy2);
94 ARG_UNUSED(dummy3);
95
96 #if defined(CONFIG_USB_DEVICE_STACK)
97 int ret;
98
99 ret = usb_enable(NULL);
100 if (ret) {
101 printk("usb backend enable failed");
102 return;
103 }
104 #endif /* CONFIG_USB_DEVICE_STACK */
105
106 /* spawn threadB */
107 k_tid_t tid = k_thread_create(&threadB_data, threadB_stack_area,
108 STACKSIZE, threadB, NULL, NULL, NULL,
109 PRIORITY, 0, K_NO_WAIT);
110
111 k_thread_name_set(tid, "thread_b");
112
113 /* invoke routine to ping-pong hello messages with threadB */
114 helloLoop(__func__, &threadA_sem, &threadB_sem);
115 }
116
117 K_THREAD_DEFINE(thread_a, STACKSIZE, threadA, NULL, NULL, NULL,
118 PRIORITY, 0, 0);
119
