1 /* 2 * Copyright (c) 2022-2023 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 /** 17 * @addtogroup DriverHdi 18 * @{ 19 * 20 * @brief Provides APIs for a system ability to obtain hardware device interface (HDI) services, 21 * load or unload a device, and listen for service status, and capabilities for the hdi-gen tool to 22 * automatically generate code in interface description language (IDL). 23 * 24 * The HDF and IDL code generated allow the system ability to accesses HDI driver services. 25 * 26 * @since 1.0 27 */ 28 29 /** 30 * @file hdi_smq_syncer.h 31 * 32 * @brief Provides communication mechanisms, including the wait() and wake() APIs, for the shared memory queue (SMQ). 33 * 34 * @since 1.0 35 */ 36 37 #ifndef HDI_SHARED_MEM_QUEUE_SYNCER_H 38 #define HDI_SHARED_MEM_QUEUE_SYNCER_H 39 40 #include <atomic> 41 #include <parcel.h> 42 #include <cstdint> 43 44 namespace OHOS { 45 namespace HDI { 46 namespace Base { 47 /** 48 * @brief Defines the <b>SharedMemQueueSyncer</b> class. 49 */ 50 class SharedMemQueueSyncer { 51 public: 52 explicit SharedMemQueueSyncer(std::atomic<uint32_t> *syncerPtr); 53 ~SharedMemQueueSyncer() = default; 54 /** 55 * @brief Enumerates the synchronization types. 56 */ 57 enum SyncWord : uint32_t { 58 /** Synchronous write */ 59 SYNC_WORD_WRITE = 0x01, 60 /** Synchronous read */ 61 SYNC_WORD_READ = 0x02, 62 }; 63 64 /** 65 * @brief Waits until a certain condition becomes true. 66 * This API will invoke the private member function <b>FutexWait</b>. 67 * 68 * @param bitset Indicates the synchronization type. 69 * @param timeoutNanoSec Indicates the time to wait, in nanoseconds. 70 * @return Returns <b>0</b> if the caller is woken up. 71 */ 72 int Wait(uint32_t bitset, int64_t timeoutNanoSec); 73 74 /** 75 * @brief Wakes up a waiter. 76 * 77 * @param bitset Indicates the synchronization type. 78 * @return Returns <b>0</b> if the waiter is woken up. 79 */ 80 int Wake(uint32_t bitset); 81 82 /** 83 * @brief Check the sync word. 84 * 85 * @param bitset Indicates the synchronization type. 86 * @return Returns <b>0</b> if the waiter is woken up. 87 */ 88 int CheckSyncStatus(uint32_t bitset); 89 90 private: 91 /** 92 * @brief Waits until a certain condition becomes true. 93 * 94 * @param bitset Indicates the synchronization type. 95 * @param timeoutNanoSec Indicates the time to wait, in nanoseconds. 96 * @return Returns <b>0</b> if the caller is woken up. 97 */ 98 int FutexWait(uint32_t bitset, int64_t timeoutNanoSec); 99 100 /** 101 * @brief Converts the wait time to real time. 102 * 103 * @param timeout Indicates the wait time. 104 * @param realtime Indicates the real time. 105 */ 106 void TimeoutToRealtime(int64_t timeout, struct timespec &realtime); 107 std::atomic<uint32_t> *syncAddr_; 108 }; 109 } // namespace Base 110 } // namespace HDI 111 } // namespace OHOS 112 113 #endif /* HDI_SHARED_MEM_QUEUE_SYNCER_H */ 114