131 lines
4.7 KiB
C++
131 lines
4.7 KiB
C++
/*
|
|
* Copyright (C) 2016 The Android Open Source Project
|
|
*
|
|
* 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
|
|
*
|
|
* http://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.
|
|
*/
|
|
|
|
#ifndef HIDL_EVENTFLAG_H
|
|
#define HIDL_EVENTFLAG_H
|
|
|
|
#include <time.h>
|
|
#include <utils/Errors.h>
|
|
#include <atomic>
|
|
|
|
namespace android {
|
|
namespace hardware {
|
|
|
|
/**
|
|
* EventFlag is an abstraction that application code utilizing FMQ can use to wait on
|
|
* conditions like full, empty, data available etc. The same EventFlag object
|
|
* can be used with multiple FMQs.
|
|
*/
|
|
struct EventFlag {
|
|
/**
|
|
* Create an event flag object from the address of the flag word.
|
|
*
|
|
* @param efWordPtr Pointer to the event flag word.
|
|
* @param status Returns a status_t error code. Likely error codes are
|
|
* NO_ERROR if the method is successful or BAD_VALUE if efWordPtr is a null
|
|
* pointer.
|
|
* @param ef Pointer to the address of the EventFlag object that gets created. Will be set to
|
|
* nullptr if unsuccesful.
|
|
*
|
|
* @return Returns a status_t error code. Likely error codes are
|
|
* NO_ERROR if the method is successful or BAD_VALUE if efAddr is a null
|
|
* pointer.
|
|
*
|
|
*/
|
|
static status_t createEventFlag(std::atomic<uint32_t>* efWordPtr,
|
|
EventFlag** ef);
|
|
|
|
/**
|
|
* Delete an EventFlag object.
|
|
*
|
|
* @param ef A double pointer to the EventFlag object to be destroyed.
|
|
*
|
|
* @return Returns a status_t error code. Likely error codes are
|
|
* NO_ERROR if the method is successful or BAD_VALUE due to
|
|
* a bad input parameter.
|
|
*/
|
|
static status_t deleteEventFlag(EventFlag** ef);
|
|
|
|
/**
|
|
* Set the specified bits of the event flag word here and wake up a thread.
|
|
* @param bitmask The bits to be set on the event flag word.
|
|
*
|
|
* @return Returns a status_t error code. Likely error codes are
|
|
* NO_ERROR if the method is successful or BAD_VALUE if the bit mask
|
|
* does not have any bits set.
|
|
*/
|
|
status_t wake(uint32_t bitmask);
|
|
|
|
/**
|
|
* Wait for any of the bits in the bit mask to be set.
|
|
*
|
|
* @param bitmask The bits to wait on.
|
|
* @param timeoutNanoSeconds Specifies timeout duration in nanoseconds. It is converted to
|
|
* an absolute timeout for the wait according to the CLOCK_MONOTONIC clock.
|
|
* @param efState The event flag bits that caused the return from wake.
|
|
* @param retry If true, retry automatically for a spurious wake. If false,
|
|
* will return -EINTR or -EAGAIN for a spurious wake.
|
|
*
|
|
* @return Returns a status_t error code. Likely error codes are
|
|
* NO_ERROR if the method is successful, BAD_VALUE due to bad input
|
|
* parameters, TIMED_OUT if the wait timedout as per the timeout
|
|
* parameter, -EAGAIN or -EINTR to indicate that the caller needs to invoke
|
|
* wait() again. -EAGAIN or -EINTR error codes will not be returned if
|
|
* 'retry' is true since the method will retry waiting in that case.
|
|
*/
|
|
status_t wait(uint32_t bitmask,
|
|
uint32_t* efState,
|
|
int64_t timeOutNanoSeconds = 0,
|
|
bool retry = false);
|
|
private:
|
|
bool mEfWordNeedsUnmapping = false;
|
|
std::atomic<uint32_t>* mEfWordPtr = nullptr;
|
|
|
|
/*
|
|
* Use this constructor if we already know where the event flag word
|
|
* lives.
|
|
*/
|
|
EventFlag(std::atomic<uint32_t>* efWordPtr, status_t* status);
|
|
|
|
/*
|
|
* Disallow constructor without argument and copying.
|
|
*/
|
|
EventFlag();
|
|
EventFlag& operator=(const EventFlag& other) = delete;
|
|
EventFlag(const EventFlag& other) = delete;
|
|
|
|
/*
|
|
* Wait for any of the bits in the bit mask to be set.
|
|
*/
|
|
status_t waitHelper(uint32_t bitmask, uint32_t* efState, int64_t timeOutNanoSeconds);
|
|
|
|
/*
|
|
* Utility method to unmap the event flag word.
|
|
*/
|
|
static status_t unmapEventFlagWord(std::atomic<uint32_t>* efWordPtr,
|
|
bool* efWordNeedsUnmapping);
|
|
|
|
/*
|
|
* Utility method to convert timeout duration to an absolute CLOCK_MONOTONIC
|
|
* clock time which is required by futex syscalls.
|
|
*/
|
|
inline void addNanosecondsToCurrentTime(int64_t nanoseconds, struct timespec* timeAbs);
|
|
~EventFlag();
|
|
};
|
|
} // namespace hardware
|
|
} // namespace android
|
|
#endif
|