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1 |
| -/* main.c - Hello World demo */ |
| 1 | +/* main.c - Synchronization demo */ |
2 | 2 |
|
3 | 3 | /*
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4 | 4 | * Copyright (c) 2012-2014 Wind River Systems, Inc.
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|
10 | 10 | #include <zephyr/sys/printk.h>
|
11 | 11 |
|
12 | 12 | /*
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13 |
| - * The hello world demo has two threads that utilize semaphores and sleeping |
| 13 | + * The synchronization demo has two threads that utilize semaphores and sleeping |
14 | 14 | * to take turns printing a greeting message at a controlled rate. The demo
|
15 | 15 | * shows both the static and dynamic approaches for spawning a thread; a real
|
16 | 16 | * world application would likely use the static approach for both threads.
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|
33 | 33 | * @param my_sem thread's own semaphore
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34 | 34 | * @param other_sem other thread's semaphore
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35 | 35 | */
|
36 |
| -void helloLoop(const char *my_name, |
37 |
| - struct k_sem *my_sem, struct k_sem *other_sem) |
| 36 | +void hello_loop(const char *my_name, |
| 37 | + struct k_sem *my_sem, struct k_sem *other_sem) |
38 | 38 | {
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39 | 39 | const char *tname;
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40 | 40 | uint8_t cpu;
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@@ -68,66 +68,61 @@ void helloLoop(const char *my_name,
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68 | 68 | }
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69 | 69 |
|
70 | 70 | /* define semaphores */
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| 71 | +K_SEM_DEFINE(thread_a_sem, 1, 1); /* starts off "available" */ |
| 72 | +K_SEM_DEFINE(thread_b_sem, 0, 1); /* starts off "not available" */ |
71 | 73 |
|
72 |
| -K_SEM_DEFINE(threadA_sem, 1, 1); /* starts off "available" */ |
73 |
| -K_SEM_DEFINE(threadB_sem, 0, 1); /* starts off "not available" */ |
74 |
| - |
75 |
| - |
76 |
| -/* threadB is a dynamic thread that is spawned by threadA */ |
77 |
| - |
78 |
| -void threadB(void *dummy1, void *dummy2, void *dummy3) |
| 74 | +/* thread_a is a dynamic thread that is spawned in main */ |
| 75 | +void thread_a_entry_point(void *dummy1, void *dummy2, void *dummy3) |
79 | 76 | {
|
80 | 77 | ARG_UNUSED(dummy1);
|
81 | 78 | ARG_UNUSED(dummy2);
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82 | 79 | ARG_UNUSED(dummy3);
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83 | 80 |
|
84 |
| - /* invoke routine to ping-pong hello messages with threadA */ |
85 |
| - helloLoop(__func__, &threadB_sem, &threadA_sem); |
| 81 | + /* invoke routine to ping-pong hello messages with thread_b */ |
| 82 | + hello_loop(__func__, &thread_a_sem, &thread_b_sem); |
86 | 83 | }
|
| 84 | +K_THREAD_STACK_DEFINE(thread_a_stack_area, STACKSIZE); |
| 85 | +static struct k_thread thread_a_data; |
87 | 86 |
|
88 |
| -K_THREAD_STACK_DEFINE(threadA_stack_area, STACKSIZE); |
89 |
| -static struct k_thread threadA_data; |
90 |
| - |
91 |
| -K_THREAD_STACK_DEFINE(threadB_stack_area, STACKSIZE); |
92 |
| -static struct k_thread threadB_data; |
93 |
| - |
94 |
| -/* threadA is a static thread that is spawned automatically */ |
95 |
| - |
96 |
| -void threadA(void *dummy1, void *dummy2, void *dummy3) |
| 87 | +/* thread_b is a static thread spawned immediately */ |
| 88 | +void thread_b_entry_point(void *dummy1, void *dummy2, void *dummy3) |
97 | 89 | {
|
98 | 90 | ARG_UNUSED(dummy1);
|
99 | 91 | ARG_UNUSED(dummy2);
|
100 | 92 | ARG_UNUSED(dummy3);
|
101 | 93 |
|
102 |
| - /* invoke routine to ping-pong hello messages with threadB */ |
103 |
| - helloLoop(__func__, &threadA_sem, &threadB_sem); |
| 94 | + /* invoke routine to ping-pong hello messages with thread_a */ |
| 95 | + hello_loop(__func__, &thread_b_sem, &thread_a_sem); |
104 | 96 | }
|
| 97 | +K_THREAD_DEFINE(thread_b, STACKSIZE, |
| 98 | + thread_b_entry_point, NULL, NULL, NULL, |
| 99 | + PRIORITY, 0, 0); |
| 100 | +extern const k_tid_t thread_b; |
105 | 101 |
|
106 | 102 | int main(void)
|
107 | 103 | {
|
108 |
| - k_thread_create(&threadA_data, threadA_stack_area, |
109 |
| - K_THREAD_STACK_SIZEOF(threadA_stack_area), |
110 |
| - threadA, NULL, NULL, NULL, |
| 104 | + k_thread_create(&thread_a_data, thread_a_stack_area, |
| 105 | + K_THREAD_STACK_SIZEOF(thread_a_stack_area), |
| 106 | + thread_a_entry_point, NULL, NULL, NULL, |
111 | 107 | PRIORITY, 0, K_FOREVER);
|
112 |
| - k_thread_name_set(&threadA_data, "thread_a"); |
113 |
| -#if PIN_THREADS |
114 |
| - if (arch_num_cpus() > 1) { |
115 |
| - k_thread_cpu_pin(&threadA_data, 0); |
116 |
| - } |
117 |
| -#endif |
| 108 | + k_thread_name_set(&thread_a_data, "thread_a"); |
118 | 109 |
|
119 |
| - k_thread_create(&threadB_data, threadB_stack_area, |
120 |
| - K_THREAD_STACK_SIZEOF(threadB_stack_area), |
121 |
| - threadB, NULL, NULL, NULL, |
122 |
| - PRIORITY, 0, K_FOREVER); |
123 |
| - k_thread_name_set(&threadB_data, "thread_b"); |
124 | 110 | #if PIN_THREADS
|
125 | 111 | if (arch_num_cpus() > 1) {
|
126 |
| - k_thread_cpu_pin(&threadB_data, 1); |
| 112 | + k_thread_cpu_pin(&thread_a_data, 0); |
| 113 | + |
| 114 | + /* |
| 115 | + * Thread b is a static thread that is spawned immediately. This means that the |
| 116 | + * following `k_thread_cpu_pin` call can fail with `-EINVAL` if the thread is |
| 117 | + * actively running. Let's suspend the thread and resume it after the affinity mask |
| 118 | + * is set. |
| 119 | + */ |
| 120 | + k_thread_suspend(thread_b); |
| 121 | + k_thread_cpu_pin(thread_b, 1); |
| 122 | + k_thread_resume(thread_b); |
127 | 123 | }
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128 | 124 | #endif
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129 | 125 |
|
130 |
| - k_thread_start(&threadA_data); |
131 |
| - k_thread_start(&threadB_data); |
| 126 | + k_thread_start(&thread_a_data); |
132 | 127 | return 0;
|
133 | 128 | }
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