70 lines
1.7 KiB
Rust
70 lines
1.7 KiB
Rust
use core::ops::{Deref, DerefMut};
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use libcortex_a9::mutex::{Mutex, MutexGuard};
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use crate::uart::Uart;
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const UART_RATE: u32 = 115_200;
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static mut UART: Mutex<LazyUart> = Mutex::new(LazyUart::Uninitialized);
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#[doc(hidden)]
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pub fn get_uart<'a>() -> MutexGuard<'a, LazyUart> {
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unsafe { UART.lock() }
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}
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pub fn drop_uart() {
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unsafe { UART = Mutex::new(LazyUart::Uninitialized); }
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}
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/// Initializes the UART on first use through `.deref_mut()` for debug
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/// output through the `print!` and `println!` macros.
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pub enum LazyUart {
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Uninitialized,
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Initialized(Uart),
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}
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impl Deref for LazyUart {
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type Target = Uart;
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fn deref(&self) -> &Uart {
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match self {
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LazyUart::Uninitialized =>
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panic!("stdio not initialized!"),
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LazyUart::Initialized(uart) =>
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uart,
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}
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}
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}
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impl DerefMut for LazyUart {
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fn deref_mut(&mut self) -> &mut Uart {
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match self {
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LazyUart::Uninitialized => {
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let uart = Uart::serial(UART_RATE);
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*self = LazyUart::Initialized(uart);
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self
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}
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LazyUart::Initialized(uart) =>
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uart,
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}
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}
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}
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#[macro_export]
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macro_rules! print {
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($($arg:tt)*) => ({
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use core::fmt::Write;
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let mut uart = $crate::stdio::get_uart();
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let _ = write!(uart, $($arg)*);
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})
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}
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#[macro_export]
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macro_rules! println {
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($($arg:tt)*) => ({
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use core::fmt::Write;
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let mut uart = $crate::stdio::get_uart();
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let _ = write!(uart, $($arg)*);
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let _ = write!(uart, "\n");
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// flush after the newline
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while !uart.tx_idle() {}
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})
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}
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