You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
57 lines
1.9 KiB
57 lines
1.9 KiB
4 months ago
|
// 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/timed_mutex.h"
|
||
|
|
|
||
|
|
#include <algorithm>
|
||
|
|
|
||
|
|
#include "RTOS.h"
|
||
|
|
#include "pw_assert/assert.h"
|
||
|
|
#include "pw_chrono/system_clock.h"
|
||
|
|
#include "pw_chrono_embos/system_clock_constants.h"
|
||
|
|
#include "pw_interrupt/context.h"
|
||
|
|
|
||
|
|
using pw::chrono::SystemClock;
|
||
|
|
|
||
|
|
namespace pw::sync {
|
||
|
|
|
||
|
|
bool TimedMutex::try_lock_for(SystemClock::duration for_at_least) {
|
||
|
|
PW_DCHECK(!interrupt::InInterruptContext());
|
||
|
|
|
||
|
|
// Use non-blocking try_lock for negative and zero length durations.
|
||
|
|
if (for_at_least <= SystemClock::duration::zero()) {
|
||
|
|
return try_lock();
|
||
|
|
}
|
||
|
|
|
||
|
|
// On a tick based kernel we cannot tell how far along we are on the current
|
||
|
|
// tick, ergo we add one whole tick to the final duration.
|
||
|
|
constexpr SystemClock::duration kMaxTimeoutMinusOne =
|
||
|
|
pw::chrono::embos::kMaxTimeout - SystemClock::duration(1);
|
||
|
|
while (for_at_least > kMaxTimeoutMinusOne) {
|
||
|
|
const int lock_count = OS_UseTimed(
|
||
|
|
&native_handle(), static_cast<OS_TIME>(kMaxTimeoutMinusOne.count()));
|
||
|
|
if (lock_count != 0) {
|
||
|
|
PW_CHECK_UINT_EQ(1, lock_count, "Recursive locking is not permitted");
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
for_at_least -= kMaxTimeoutMinusOne;
|
||
|
|
}
|
||
|
|
const int lock_count = OS_UseTimed(
|
||
|
|
&native_handle(), static_cast<OS_TIME>(for_at_least.count() + 1));
|
||
|
|
PW_CHECK_UINT_LE(1, lock_count, "Recursive locking is not permitted");
|
||
|
|
return lock_count == 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
} // namespace pw::sync
|