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rework RP2040 PIO UART interrupt path #840

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Merged
HaoboGu merged 1 commit into from
May 10, 2026
Merged

rework RP2040 PIO UART interrupt path #840

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43 changes: 28 additions & 15 deletions rmk/src/split/rp/uart.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -425,11 +425,18 @@ impl<PIO: Instance + UartPioAccess> Handler<PIO::Interrupt> for UartInterruptHan
let mut writer = unsafe { PIO::uart_buffer().buf_rx.writer() };
let rx_buf = writer.push_slice();
if rx_buf.len() > 0 {
// SM1 RX FIFO is joined (FifoJoin::RxOnly), so depth is 8.
let mut n = 0;
while (pio.fstat().read().rxempty() & 1 << 1 as u8) == 0 && n < rx_buf.len() {
let byte = pio.rxf(1).read();
rx_buf[n] = (byte >> 24) as u8;
n += 1;
while n < rx_buf.len() {
let avail = pio.flevel().read().rx1() as usize;
if avail == 0 {
break;
}
let take = avail.min(rx_buf.len() - n);
for slot in &mut rx_buf[n..n + take] {
*slot = (pio.rxf(1).read() >> 24) as u8;
}
n += take;
}
writer.push_done(n);
PIO::Interrupt::unpend();
Expand All @@ -442,23 +449,29 @@ impl<PIO: Instance + UartPioAccess> Handler<PIO::Interrupt> for UartInterruptHan
PIO::Interrupt::unpend();
if PIO::uart_buffer().buf_tx.is_available() {
// Full-Duplex Mode
if !PIO::uart_buffer().buf_tx.is_full() {
let mut reader = unsafe { PIO::uart_buffer().buf_tx.reader() };
let tx_buf = reader.pop_slice();
let mut n = 0;
while (pio.fstat().read().txfull() & 1 << 0 as u8) == 0 && n < tx_buf.len() {
let byte = tx_buf[n];
pio.txf(0).write(|f| *f = byte as u32);
n += 1;
let mut reader = unsafe { PIO::uart_buffer().buf_tx.reader() };
let tx_buf = reader.pop_slice();
// SM0 TX FIFO is joined (FifoJoin::TxOnly), so depth is 8.
const TX_FIFO_DEPTH: usize = 8;
let mut n = 0;
while n < tx_buf.len() {
let free = TX_FIFO_DEPTH - pio.flevel().read().tx0() as usize;
if free == 0 {
break;
}
let push = free.min(tx_buf.len() - n);
for byte in &tx_buf[n..n + push] {
pio.txf(0).write(|f| *f = *byte as u32);
}
reader.pop_done(n);
n += push;
}
reader.pop_done(n);
if PIO::uart_buffer().buf_tx.is_empty() {
PIO::regs().irqs(0).inte().modify(|i| i.set_sm0_txnfull(false));
pio.irqs(0).inte().modify(|i| i.set_sm0_txnfull(false));
}
} else {
// Half-Duplex Mode
PIO::regs().irqs(0).inte().modify(|i| i.set_sm0_txnfull(false));
pio.irqs(0).inte().modify(|i| i.set_sm0_txnfull(false));
PIO::uart_buffer().waker_tx.wake();
}
}
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