98 lines
2.4 KiB
Rust
98 lines
2.4 KiB
Rust
// Copyright (c) 2025 taitep
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// SPDX-License-Identifier: MIT
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//
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// This file is part of TRVE (https://gitea.taitep.se/taitep/trve)
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// See LICENSE file in the project root for full license text.
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use std::collections::VecDeque;
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use std::io;
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use std::os::fd::AsFd;
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use std::sync::{Arc, Mutex};
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use std::thread;
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use std::time::Duration;
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use nix::fcntl::fcntl;
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use nix::fcntl::{FcntlArg, OFlag};
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use trve::consts::{Addr, Byte};
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use trve::exceptions::MemoryExceptionType;
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use trve::mem::MemDeviceInterface;
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/// byte 0: rx/tx
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/// byte 1: status (------rt, r=rxready, t=txready)/none
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pub struct BasicUart {
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rx_buf: Mutex<VecDeque<u8>>,
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}
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impl BasicUart {
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pub fn new() -> Self {
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// Make sure stdin is nonblocking
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let stdin = io::stdin();
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let fd = stdin.as_fd();
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let flags = fcntl(fd, FcntlArg::F_GETFL).unwrap();
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fcntl(
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fd,
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FcntlArg::F_SETFL(OFlag::from_bits_truncate(flags) | OFlag::O_NONBLOCK),
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)
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.unwrap();
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BasicUart {
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rx_buf: Mutex::new(VecDeque::new()),
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}
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}
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pub fn spawn_poller(self, poll_interval: Duration) -> Arc<Self> {
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let shared = Arc::new(self);
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let uart_clone = shared.clone();
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thread::spawn(move || {
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loop {
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uart_clone.poll();
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thread::sleep(poll_interval);
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}
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});
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shared
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}
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fn write(&self, byte: u8) {
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print!("{}", byte as char);
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}
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fn read(&self) -> u8 {
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self.rx_buf.lock().unwrap().pop_front().unwrap_or(0)
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}
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fn can_read(&self) -> bool {
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!self.rx_buf.lock().unwrap().is_empty()
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}
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pub fn poll(&self) {
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let mut rx_buf = self.rx_buf.lock().unwrap();
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let mut buffer = [0u8; 1];
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while let Ok(1) = nix::unistd::read(io::stdin().as_fd(), &mut buffer) {
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rx_buf.push_back(buffer[0]);
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}
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}
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}
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impl MemDeviceInterface for BasicUart {
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fn write_byte(&self, addr: Addr, value: Byte) -> Result<(), MemoryExceptionType> {
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match addr {
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0 => {
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self.write(value);
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Ok(())
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}
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_ => Err(MemoryExceptionType::AccessFault),
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}
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}
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fn read_byte(&self, addr: Addr) -> Result<Byte, MemoryExceptionType> {
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match addr {
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0 => Ok(self.read()),
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1 => Ok(1 | (self.can_read() as u8) << 1),
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_ => Err(MemoryExceptionType::AccessFault),
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}
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}
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}
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