1 // Copyright 2020 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
15 #include <cstddef>
16
17 #include "pw_hdlc/rpc_channel.h"
18 #include "pw_hdlc/rpc_packets.h"
19 #include "pw_log/log.h"
20 #include "pw_rpc_system_server/rpc_server.h"
21 #include "pw_stream/sys_io_stream.h"
22
23 namespace pw::rpc::system_server {
24 namespace {
25
26 constexpr size_t kMaxTransmissionUnit = 256;
27
28 // Used to write HDLC data to pw::sys_io.
29 stream::SysIoWriter writer;
30 stream::SysIoReader reader;
31
32 // Set up the output channel for the pw_rpc server to use.
33 hdlc::RpcChannelOutput hdlc_channel_output(writer,
34 pw::hdlc::kDefaultRpcAddress,
35 "HDLC channel");
36 Channel channels[] = {pw::rpc::Channel::Create<1>(&hdlc_channel_output)};
37 rpc::Server server(channels);
38
39 } // namespace
40
Init()41 void Init() {
42 // Send log messages to HDLC address 1. This prevents logs from interfering
43 // with pw_rpc communications.
44 pw::log_basic::SetOutput([](std::string_view log) {
45 pw::hdlc::WriteUIFrame(1, std::as_bytes(std::span(log)), writer);
46 });
47 }
48
Server()49 rpc::Server& Server() { return server; }
50
Start()51 Status Start() {
52 // Declare a buffer for decoding incoming HDLC frames.
53 std::array<std::byte, kMaxTransmissionUnit> input_buffer;
54 hdlc::Decoder decoder(input_buffer);
55
56 while (true) {
57 std::byte byte;
58 Status ret_val = pw::sys_io::ReadByte(&byte);
59 if (!ret_val.ok()) {
60 return ret_val;
61 }
62 if (auto result = decoder.Process(byte); result.ok()) {
63 hdlc::Frame& frame = result.value();
64 if (frame.address() == hdlc::kDefaultRpcAddress) {
65 server.ProcessPacket(frame.data(), hdlc_channel_output);
66 }
67 }
68 }
69 }
70
71 } // namespace pw::rpc::system_server
72