1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2026-present Eclipse ThreadX contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Semaphore */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_trace.h"
#include "tx_thread.h"
#include "tx_semaphore.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_semaphore_get PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function gets an instance from the specified counting */
/* semaphore. */
/* */
/* INPUT */
/* */
/* semaphore_ptr Pointer to semaphore control block*/
/* wait_option Suspension option */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _tx_thread_system_suspend Suspend thread service */
/* _tx_thread_system_ni_suspend Non-interruptable suspend thread */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/**************************************************************************/
UINT _tx_semaphore_get(TX_SEMAPHORE *semaphore_ptr, ULONG wait_option)
{
TX_INTERRUPT_SAVE_AREA
TX_THREAD *thread_ptr;
TX_THREAD *next_thread;
TX_THREAD *previous_thread;
UINT status;
/* Default the status to TX_SUCCESS. */
status = TX_SUCCESS;
/* Disable interrupts to get an instance from the semaphore. */
TX_DISABLE
#ifdef TX_SEMAPHORE_ENABLE_PERFORMANCE_INFO
/* Increment the total semaphore get counter. */
_tx_semaphore_performance_get_count++;
/* Increment the number of attempts to get this semaphore. */
semaphore_ptr -> tx_semaphore_performance_get_count++;
#endif
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_SEMAPHORE_GET, semaphore_ptr, wait_option, semaphore_ptr -> tx_semaphore_count, TX_POINTER_TO_ULONG_CONVERT(&thread_ptr), TX_TRACE_SEMAPHORE_EVENTS)
/* Log this kernel call. */
TX_EL_SEMAPHORE_GET_INSERT
/* Determine if there is an instance of the semaphore. */
if (semaphore_ptr -> tx_semaphore_count != ((ULONG) 0))
{
/* Decrement the semaphore count. */
semaphore_ptr -> tx_semaphore_count--;
/* Restore interrupts. */
TX_RESTORE
}
/* Determine if the request specifies suspension. */
else if (wait_option != TX_NO_WAIT)
{
/* Determine if the preempt disable flag is non-zero. */
if (_tx_thread_preempt_disable != ((UINT) 0))
{
/* Restore interrupts. */
TX_RESTORE
/* Suspension is not allowed if the preempt disable flag is non-zero at this point - return error completion. */
status = TX_NO_INSTANCE;
}
else
{
/* Prepare for suspension of this thread. */
#ifdef TX_SEMAPHORE_ENABLE_PERFORMANCE_INFO
/* Increment the total semaphore suspensions counter. */
_tx_semaphore_performance_suspension_count++;
/* Increment the number of suspensions on this semaphore. */
semaphore_ptr -> tx_semaphore_performance_suspension_count++;
#endif
/* Pickup thread pointer. */
TX_THREAD_GET_CURRENT(thread_ptr)
/* Setup cleanup routine pointer. */
thread_ptr -> tx_thread_suspend_cleanup = &(_tx_semaphore_cleanup);
/* Setup cleanup information, i.e. this semaphore control
block. */
thread_ptr -> tx_thread_suspend_control_block = (VOID *) semaphore_ptr;
#ifndef TX_NOT_INTERRUPTABLE
/* Increment the suspension sequence number, which is used to identify
this suspension event. */
thread_ptr -> tx_thread_suspension_sequence++;
#endif
/* Setup suspension list. */
if (semaphore_ptr -> tx_semaphore_suspended_count == TX_NO_SUSPENSIONS)
{
/* No other threads are suspended. Setup the head pointer and
just setup this threads pointers to itself. */
semaphore_ptr -> tx_semaphore_suspension_list = thread_ptr;
thread_ptr -> tx_thread_suspended_next = thread_ptr;
thread_ptr -> tx_thread_suspended_previous = thread_ptr;
}
else
{
/* This list is not NULL, add current thread to the end. */
next_thread = semaphore_ptr -> tx_semaphore_suspension_list;
thread_ptr -> tx_thread_suspended_next = next_thread;
previous_thread = next_thread -> tx_thread_suspended_previous;
thread_ptr -> tx_thread_suspended_previous = previous_thread;
previous_thread -> tx_thread_suspended_next = thread_ptr;
next_thread -> tx_thread_suspended_previous = thread_ptr;
}
/* Increment the number of suspensions. */
semaphore_ptr -> tx_semaphore_suspended_count++;
/* Set the state to suspended. */
thread_ptr -> tx_thread_state = TX_SEMAPHORE_SUSP;
#ifdef TX_NOT_INTERRUPTABLE
/* Call actual non-interruptable thread suspension routine. */
_tx_thread_system_ni_suspend(thread_ptr, wait_option);
/* Restore interrupts. */
TX_RESTORE
#else
/* Set the suspending flag. */
thread_ptr -> tx_thread_suspending = TX_TRUE;
/* Setup the timeout period. */
thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = wait_option;
/* Temporarily disable preemption. */
_tx_thread_preempt_disable++;
/* Restore interrupts. */
TX_RESTORE
/* Call actual thread suspension routine. */
_tx_thread_system_suspend(thread_ptr);
#endif
/* Return the completion status. */
status = thread_ptr -> tx_thread_suspend_status;
}
}
else
{
/* Restore interrupts. */
TX_RESTORE
/* Immediate return, return error completion. */
status = TX_NO_INSTANCE;
}
/* Return completion status. */
return(status);
}
|
