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
|
// Copyright 2021 The Pigweed Authors
//
// 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
//
// https://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.
#include "pw_sync/thread_notification.h"
#include "FreeRTOS.h"
#include "pw_assert/check.h"
#include "pw_interrupt/context.h"
#include "pw_sync_freertos/config.h"
#include "task.h"
namespace pw::sync {
namespace {
BaseType_t WaitForNotification(TickType_t xTicksToWait) {
#ifdef configTASK_NOTIFICATION_ARRAY_ENTRIES
return xTaskNotifyWaitIndexed(
pw::sync::freertos::config::kThreadNotificationIndex,
0, // Clear no bits on entry.
0, // Clear no bits on exit.
nullptr, // Don't care about the notification value.
xTicksToWait);
#else // !configTASK_NOTIFICATION_ARRAY_ENTRIES
return xTaskNotifyWait(0, // Clear no bits on entry.
0, // Clear no bits on exit.
nullptr, // Don't care about the notification value.
xTicksToWait);
#endif // configTASK_NOTIFICATION_ARRAY_ENTRIES
}
} // namespace
void ThreadNotification::acquire() {
// Enforce the pw::sync::ThreadNotification IRQ contract.
PW_DCHECK(!interrupt::InInterruptContext());
// Enforce that only a single thread can block at a time.
PW_DCHECK(native_type_.blocked_thread == nullptr);
// Ensure that no one forgot to clean up nor corrupted the task notification
// state in the TCB.
PW_DCHECK(xTaskNotifyStateClear(nullptr) == pdFALSE);
taskENTER_CRITICAL();
if (native_type_.notified) {
native_type_.notified = false;
taskEXIT_CRITICAL();
return;
}
// Not notified yet, set the task handle for a one-time notification.
native_type_.blocked_thread = xTaskGetCurrentTaskHandle();
taskEXIT_CRITICAL();
#if INCLUDE_vTaskSuspend == 1 // This means portMAX_DELAY is indefinite.
const BaseType_t result = WaitForNotification(portMAX_DELAY);
PW_DCHECK_UINT_EQ(result, pdTRUE);
#else // INCLUDE_vTaskSuspend != 1
while (WaitForNotification(portMAX_DELAY) == pdFALSE) {
}
#endif // INCLUDE_vTaskSuspend
taskENTER_CRITICAL();
// The task handle was cleared by the notifier.
// Note that this may hide another notification, however this is considered
// a form of notification saturation just like as if this happened before
// acquire() was invoked.
native_type_.notified = false;
taskEXIT_CRITICAL();
}
void ThreadNotification::release() {
if (!interrupt::InInterruptContext()) { // Task context
taskENTER_CRITICAL();
if (native_type_.blocked_thread != nullptr) {
#ifdef configTASK_NOTIFICATION_ARRAY_ENTRIES
xTaskNotifyIndexed(native_type_.blocked_thread,
pw::sync::freertos::config::kThreadNotificationIndex,
0u,
eNoAction);
#else // !configTASK_NOTIFICATION_ARRAY_ENTRIES
xTaskNotify(native_type_.blocked_thread, 0u, eNoAction);
#endif // configTASK_NOTIFICATION_ARRAY_ENTRIES
native_type_.blocked_thread = nullptr;
}
native_type_.notified = true;
taskEXIT_CRITICAL();
return;
}
// Interrupt context
const UBaseType_t saved_interrupt_mask = taskENTER_CRITICAL_FROM_ISR();
if (native_type_.blocked_thread != nullptr) {
BaseType_t woke_higher_task = pdFALSE;
#ifdef configTASK_NOTIFICATION_ARRAY_ENTRIES
xTaskNotifyIndexedFromISR(
native_type_.blocked_thread,
pw::sync::freertos::config::kThreadNotificationIndex,
0u,
eNoAction,
&woke_higher_task);
#else // !configTASK_NOTIFICATION_ARRAY_ENTRIES
xTaskNotifyFromISR(
native_type_.blocked_thread, 0u, eNoAction, &woke_higher_task);
#endif // configTASK_NOTIFICATION_ARRAY_ENTRIES
native_type_.blocked_thread = nullptr;
portYIELD_FROM_ISR(woke_higher_task);
}
native_type_.notified = true;
taskEXIT_CRITICAL_FROM_ISR(saved_interrupt_mask);
}
} // namespace pw::sync
|
