1 // Copyright 2023 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://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, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <cstdint> 17 18 #include "fsl_mu.h" 19 #include "pw_bytes/span.h" 20 #include "pw_status/status.h" 21 #include "pw_stream/stream.h" 22 #include "pw_sync/binary_semaphore.h" 23 24 namespace pw::stream { 25 26 // Stream for reading/writing between processor cores using the Mcuxpresso SDK. 27 // 28 // It uses the MU module from the SDK for signaling data readiness. MU channels 29 // 0 and 1 are claimed for exclusive use. Each core should have an instance of 30 // this class with shared buffers pointing at the same physical memory locations 31 // that is uncached on both sides. 32 // 33 // Interrupt setup is different between cores, so that is left to the user. An 34 // example can be found in the docs. In the MU interrupt handler on each core, 35 // the `HandleInterrupt` function on the stream should be called. 36 class ShmemMcuxpressoStream : public NonSeekableReaderWriter { 37 public: ShmemMcuxpressoStream(MU_Type * base,ByteSpan shared_read_buffer,ByteSpan shared_write_buffer)38 ShmemMcuxpressoStream(MU_Type* base, 39 ByteSpan shared_read_buffer, 40 ByteSpan shared_write_buffer) 41 : base_(base), 42 shared_read_buffer_(shared_read_buffer), 43 shared_write_buffer_(shared_write_buffer) {} 44 ~ShmemMcuxpressoStream(); 45 46 void Enable(); 47 void Disable(); 48 49 // To be called when MU interrupt fires. 50 void HandleInterrupt(); 51 52 private: 53 StatusWithSize DoRead(ByteSpan) override; 54 Status DoWrite(ConstByteSpan) override; 55 56 MU_Type* const base_; 57 ByteSpan shared_read_buffer_; 58 ByteSpan shared_write_buffer_; 59 sync::BinarySemaphore read_semaphore_; 60 sync::BinarySemaphore write_semaphore_; 61 sync::BinarySemaphore write_done_semaphore_; 62 }; 63 64 } // namespace pw::stream 65