/*
* 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 _FMSGQ_DESCRIPTOR_H
#define _FMSGQ_DESCRIPTOR_H
#include <unistd.h>
#include <cutils/native_handle.h>
#include <hidl/HidlInternal.h>
#include <hidl/HidlSupport.h>
namespace android {
namespace hardware {
typedef uint64_t RingBufferPosition;
struct GrantorDescriptor {
uint32_t flags __attribute__ ((aligned(4)));
uint32_t fdIndex __attribute__ ((aligned(4)));
uint32_t offset __attribute__ ((aligned(4)));
uint64_t extent __attribute__ ((aligned(8)));
};
static_assert(offsetof(GrantorDescriptor, flags) == 0, "wrong offset");
static_assert(offsetof(GrantorDescriptor, fdIndex) == 4, "wrong offset");
static_assert(offsetof(GrantorDescriptor, offset) == 8, "wrong offset");
static_assert(offsetof(GrantorDescriptor, extent) == 16, "wrong offset");
static_assert(sizeof(GrantorDescriptor) == 24, "wrong size");
static_assert(__alignof(GrantorDescriptor) == 8, "wrong alignment");
enum MQFlavor : uint32_t {
/*
* kSynchronizedReadWrite represents the wait-free synchronized flavor of the
* FMQ. It is intended to be have a single reader and single writer.
* Attempts to overflow/underflow returns a failure.
*/
kSynchronizedReadWrite = 0x01,
/*
* kUnsynchronizedWrite represents the flavor of FMQ where writes always
* succeed. This flavor allows one writer and many readers. A read operation
* can detect an overwrite and reset the read counter.
*/
kUnsynchronizedWrite = 0x02
};
template <typename T, MQFlavor flavor>
struct MQDescriptor {
MQDescriptor(
const std::vector<GrantorDescriptor>& grantors,
native_handle_t* nHandle, size_t size);
MQDescriptor(size_t bufferSize, native_handle_t* nHandle,
size_t messageSize, bool configureEventFlag = false);
MQDescriptor();
~MQDescriptor();
explicit MQDescriptor(const MQDescriptor &other);
MQDescriptor &operator=(const MQDescriptor &other) = delete;
size_t getSize() const;
size_t getQuantum() const;
int32_t getFlags() const;
bool isHandleValid() const { return mHandle != nullptr; }
size_t countGrantors() const { return mGrantors.size(); }
inline const ::android::hardware::hidl_vec<GrantorDescriptor> &grantors() const {
return mGrantors;
}
inline ::android::hardware::hidl_vec<GrantorDescriptor> &grantors() {
return mGrantors;
}
inline const ::native_handle_t *handle() const {
return mHandle;
}
inline ::native_handle_t *handle() {
return mHandle;
}
static const size_t kOffsetOfGrantors;
static const size_t kOffsetOfHandle;
enum GrantorType : int { READPTRPOS = 0, WRITEPTRPOS, DATAPTRPOS, EVFLAGWORDPOS };
/*
* There should at least be GrantorDescriptors for the read counter, write
* counter and data buffer. A GrantorDescriptor for an EventFlag word is
* not required if there is no need for blocking FMQ operations.
*/
static constexpr int32_t kMinGrantorCount = DATAPTRPOS + 1;
/*
* Minimum number of GrantorDescriptors required if EventFlag support is
* needed for blocking FMQ operations.
*/
static constexpr int32_t kMinGrantorCountForEvFlagSupport = EVFLAGWORDPOS + 1;
//TODO(b/34160777) Identify a better solution that supports remoting.
static inline size_t alignToWordBoundary(size_t length) {
constexpr size_t kAlignmentSize = 64;
if (kAlignmentSize % __WORDSIZE != 0) {
details::logAlwaysFatal("Incompatible word size");
}
/*
* Check if alignment to word boundary would cause an overflow.
*/
if (length > SIZE_MAX - kAlignmentSize/8 + 1) {
details::logAlwaysFatal("Queue size too large");
}
return (length + kAlignmentSize/8 - 1) & ~(kAlignmentSize/8 - 1U);
}
static inline size_t isAlignedToWordBoundary(size_t offset) {
constexpr size_t kAlignmentSize = 64;
return (offset & (kAlignmentSize/8 - 1)) == 0;
}
private:
::android::hardware::hidl_vec<GrantorDescriptor> mGrantors;
::android::hardware::details::hidl_pointer<native_handle_t> mHandle;
uint32_t mQuantum;
uint32_t mFlags;
};
template<typename T, MQFlavor flavor>
const size_t MQDescriptor<T, flavor>::kOffsetOfGrantors = offsetof(MQDescriptor, mGrantors);
template<typename T, MQFlavor flavor>
const size_t MQDescriptor<T, flavor>::kOffsetOfHandle = offsetof(MQDescriptor, mHandle);
/*
* MQDescriptorSync will describe the wait-free synchronized
* flavor of FMQ.
*/
template<typename T>
using MQDescriptorSync = MQDescriptor<T, kSynchronizedReadWrite>;
/*
* MQDescriptorUnsync will describe the unsynchronized write
* flavor of FMQ.
*/
template<typename T>
using MQDescriptorUnsync = MQDescriptor<T, kUnsynchronizedWrite>;
template<typename T, MQFlavor flavor>
MQDescriptor<T, flavor>::MQDescriptor(
const std::vector<GrantorDescriptor>& grantors,
native_handle_t* nhandle,
size_t size)
: mHandle(nhandle),
mQuantum(size),
mFlags(flavor) {
mGrantors.resize(grantors.size());
for (size_t i = 0; i < grantors.size(); ++i) {
if (isAlignedToWordBoundary(grantors[i].offset) == false) {
details::logAlwaysFatal("Grantor offsets need to be aligned");
}
mGrantors[i] = grantors[i];
}
}
template<typename T, MQFlavor flavor>
MQDescriptor<T, flavor>::MQDescriptor(size_t bufferSize, native_handle_t *nHandle,
size_t messageSize, bool configureEventFlag)
: mHandle(nHandle), mQuantum(messageSize), mFlags(flavor) {
/*
* If configureEventFlag is true, allocate an additional spot in mGrantor
* for containing the fd and offset for mmapping the EventFlag word.
*/
mGrantors.resize(configureEventFlag? kMinGrantorCountForEvFlagSupport : kMinGrantorCount);
size_t memSize[] = {
sizeof(RingBufferPosition), /* memory to be allocated for read pointer counter */
sizeof(RingBufferPosition), /* memory to be allocated for write pointer counter */
bufferSize, /* memory to be allocated for data buffer */
sizeof(std::atomic<uint32_t>)/* memory to be allocated for EventFlag word */
};
/*
* Create a default grantor descriptor for read, write pointers and
* the data buffer. fdIndex parameter is set to 0 by default and
* the offset for each grantor is contiguous.
*/
for (size_t grantorPos = 0, offset = 0;
grantorPos < mGrantors.size();
offset += memSize[grantorPos++]) {
mGrantors[grantorPos] = {
0 /* grantor flags */,
0 /* fdIndex */,
static_cast<uint32_t>(alignToWordBoundary(offset)),
memSize[grantorPos]
};
}
}
template<typename T, MQFlavor flavor>
MQDescriptor<T, flavor>::MQDescriptor(const MQDescriptor<T, flavor> &other)
: mGrantors(other.mGrantors),
mHandle(nullptr),
mQuantum(other.mQuantum),
mFlags(other.mFlags) {
if (other.mHandle != nullptr) {
mHandle = native_handle_create(
other.mHandle->numFds, other.mHandle->numInts);
for (int i = 0; i < other.mHandle->numFds; ++i) {
mHandle->data[i] = dup(other.mHandle->data[i]);
}
memcpy(&mHandle->data[other.mHandle->numFds],
&other.mHandle->data[other.mHandle->numFds],
other.mHandle->numInts * sizeof(int));
}
}
template<typename T, MQFlavor flavor>
MQDescriptor<T, flavor>::MQDescriptor() : MQDescriptor(
std::vector<android::hardware::GrantorDescriptor>(),
nullptr /* nHandle */,
0 /* size */) {}
template<typename T, MQFlavor flavor>
MQDescriptor<T, flavor>::~MQDescriptor() {
if (mHandle != nullptr) {
native_handle_close(mHandle);
native_handle_delete(mHandle);
}
}
template<typename T, MQFlavor flavor>
size_t MQDescriptor<T, flavor>::getSize() const {
return mGrantors[DATAPTRPOS].extent;
}
template<typename T, MQFlavor flavor>
size_t MQDescriptor<T, flavor>::getQuantum() const { return mQuantum; }
template<typename T, MQFlavor flavor>
int32_t MQDescriptor<T, flavor>::getFlags() const { return mFlags; }
template<typename T, MQFlavor flavor>
std::string toString(const MQDescriptor<T, flavor> &q) {
std::string os;
if (flavor & kSynchronizedReadWrite) {
os += "fmq_sync";
}
if (flavor & kUnsynchronizedWrite) {
os += "fmq_unsync";
}
os += " {"
+ toString(q.grantors().size()) + " grantor(s), "
+ "size = " + toString(q.getSize())
+ ", .handle = " + toString(q.handle())
+ ", .quantum = " + toString(q.getQuantum()) + "}";
return os;
}
} // namespace hardware
} // namespace android
#endif // FMSGQ_DESCRIPTOR_H