Devin Moore | 133cb5e | 2020-07-07 16:31:22 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2020 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #pragma once |
| 18 | |
| 19 | #include <assert.h> |
Devin Moore | cfb5985 | 2020-08-25 15:47:19 -0700 | [diff] [blame] | 20 | #include <string> |
Devin Moore | 133cb5e | 2020-07-07 16:31:22 -0700 | [diff] [blame] | 21 | |
| 22 | namespace android { |
| 23 | namespace hardware { |
| 24 | |
| 25 | enum MQFlavor : uint32_t { |
| 26 | /* |
| 27 | * kSynchronizedReadWrite represents the wait-free synchronized flavor of the |
| 28 | * FMQ. It is intended to be have a single reader and single writer. |
| 29 | * Attempts to overflow/underflow returns a failure. |
| 30 | */ |
| 31 | kSynchronizedReadWrite = 0x01, |
| 32 | /* |
| 33 | * kUnsynchronizedWrite represents the flavor of FMQ where writes always |
| 34 | * succeed. This flavor allows one writer and many readers. A read operation |
| 35 | * can detect an overwrite and reset the read counter. |
| 36 | */ |
| 37 | kUnsynchronizedWrite = 0x02 |
| 38 | }; |
| 39 | |
Devin Moore | 7c04cfe | 2020-08-17 14:37:13 -0700 | [diff] [blame] | 40 | struct GrantorDescriptor { |
| 41 | uint32_t flags __attribute__((aligned(4))); |
| 42 | uint32_t fdIndex __attribute__((aligned(4))); |
| 43 | uint32_t offset __attribute__((aligned(4))); |
| 44 | uint64_t extent __attribute__((aligned(8))); |
| 45 | }; |
| 46 | |
| 47 | static_assert(offsetof(GrantorDescriptor, flags) == 0, "wrong offset"); |
| 48 | static_assert(offsetof(GrantorDescriptor, fdIndex) == 4, "wrong offset"); |
| 49 | static_assert(offsetof(GrantorDescriptor, offset) == 8, "wrong offset"); |
| 50 | static_assert(offsetof(GrantorDescriptor, extent) == 16, "wrong offset"); |
| 51 | static_assert(sizeof(GrantorDescriptor) == 24, "wrong size"); |
| 52 | static_assert(__alignof(GrantorDescriptor) == 8, "wrong alignment"); |
| 53 | |
Devin Moore | 133cb5e | 2020-07-07 16:31:22 -0700 | [diff] [blame] | 54 | namespace details { |
| 55 | |
Devin Moore | cfb5985 | 2020-08-25 15:47:19 -0700 | [diff] [blame] | 56 | void logError(const std::string& message); |
Devin Moore | 2741a81 | 2021-04-29 16:22:51 -0700 | [diff] [blame] | 57 | void errorWriteLog(int tag, const char* message); |
Devin Moore | cfb5985 | 2020-08-25 15:47:19 -0700 | [diff] [blame] | 58 | |
Devin Moore | 133cb5e | 2020-07-07 16:31:22 -0700 | [diff] [blame] | 59 | typedef uint64_t RingBufferPosition; |
| 60 | enum GrantorType : int { READPTRPOS = 0, WRITEPTRPOS, DATAPTRPOS, EVFLAGWORDPOS }; |
| 61 | /* |
| 62 | * There should at least be GrantorDescriptors for the read counter, write |
| 63 | * counter and data buffer. A GrantorDescriptor for an EventFlag word is |
| 64 | * not required if there is no need for blocking FMQ operations. |
| 65 | */ |
| 66 | static constexpr int32_t kMinGrantorCount = DATAPTRPOS + 1; |
| 67 | |
| 68 | /* |
| 69 | * Minimum number of GrantorDescriptors required if EventFlag support is |
| 70 | * needed for blocking FMQ operations. |
| 71 | */ |
| 72 | static constexpr int32_t kMinGrantorCountForEvFlagSupport = EVFLAGWORDPOS + 1; |
| 73 | |
| 74 | static inline size_t alignToWordBoundary(size_t length) { |
| 75 | constexpr size_t kAlignmentSize = 64; |
| 76 | if (kAlignmentSize % __WORDSIZE != 0) { |
| 77 | #ifdef __BIONIC__ |
| 78 | __assert(__FILE__, __LINE__, "Incompatible word size"); |
| 79 | #endif |
| 80 | } |
| 81 | |
| 82 | /* |
| 83 | * Check if alignment to word boundary would cause an overflow. |
| 84 | */ |
| 85 | if (length > SIZE_MAX - kAlignmentSize / 8 + 1) { |
| 86 | #ifdef __BIONIC__ |
| 87 | __assert(__FILE__, __LINE__, "Queue size too large"); |
| 88 | #endif |
| 89 | } |
| 90 | |
| 91 | return (length + kAlignmentSize / 8 - 1) & ~(kAlignmentSize / 8 - 1U); |
| 92 | } |
| 93 | |
| 94 | static inline size_t isAlignedToWordBoundary(size_t offset) { |
| 95 | constexpr size_t kAlignmentSize = 64; |
| 96 | return (offset & (kAlignmentSize / 8 - 1)) == 0; |
| 97 | } |
| 98 | |
| 99 | } // namespace details |
| 100 | } // namespace hardware |
| 101 | } // namespace android |