artiq/artiq/firmware/libboard_artiq/drtioaux.rs

152 lines
4.3 KiB
Rust

use core::slice;
use crc;
use io::{ProtoRead, ProtoWrite, Cursor, Error as IoError};
use board_misoc::{csr::DRTIOAUX, mem::DRTIOAUX_MEM, clock};
use proto_artiq::drtioaux_proto::Error as ProtocolError;
pub use proto_artiq::drtioaux_proto::Packet;
// this is parametric over T because there's no impl Fail for !.
#[derive(Fail, Debug)]
pub enum Error<T> {
#[fail(display = "gateware reported error")]
GatewareError,
#[fail(display = "packet CRC failed")]
CorruptedPacket,
#[fail(display = "link is down")]
LinkDown,
#[fail(display = "timed out waiting for data")]
TimedOut,
#[fail(display = "unexpected reply")]
UnexpectedReply,
#[fail(display = "routing error")]
RoutingError,
#[fail(display = "protocol error: {}", _0)]
Protocol(#[cause] ProtocolError<T>)
}
impl<T> From<ProtocolError<T>> for Error<T> {
fn from(value: ProtocolError<T>) -> Error<T> {
Error::Protocol(value)
}
}
impl<T> From<IoError<T>> for Error<T> {
fn from(value: IoError<T>) -> Error<T> {
Error::Protocol(ProtocolError::Io(value))
}
}
pub fn reset(linkno: u8) {
let linkno = linkno as usize;
unsafe {
// clear buffer first to limit race window with buffer overflow
// error. We assume the CPU is fast enough so that no two packets
// will be received between the buffer and the error flag are cleared.
(DRTIOAUX[linkno].aux_rx_present_write)(1);
(DRTIOAUX[linkno].aux_rx_error_write)(1);
}
}
fn has_rx_error(linkno: u8) -> bool {
let linkno = linkno as usize;
unsafe {
let error = (DRTIOAUX[linkno].aux_rx_error_read)() != 0;
if error {
(DRTIOAUX[linkno].aux_rx_error_write)(1)
}
error
}
}
fn receive<F, T>(linkno: u8, f: F) -> Result<Option<T>, Error<!>>
where F: FnOnce(&[u8]) -> Result<T, Error<!>>
{
let linkidx = linkno as usize;
unsafe {
if (DRTIOAUX[linkidx].aux_rx_present_read)() == 1 {
let ptr = DRTIOAUX_MEM[linkidx].base + DRTIOAUX_MEM[linkidx].size / 2;
let len = (DRTIOAUX[linkidx].aux_rx_length_read)();
let result = f(slice::from_raw_parts(ptr as *mut u8, len as usize));
(DRTIOAUX[linkidx].aux_rx_present_write)(1);
Ok(Some(result?))
} else {
Ok(None)
}
}
}
pub fn recv(linkno: u8) -> Result<Option<Packet>, Error<!>> {
if has_rx_error(linkno) {
return Err(Error::GatewareError)
}
receive(linkno, |buffer| {
if buffer.len() < 8 {
return Err(IoError::UnexpectedEnd.into())
}
let mut reader = Cursor::new(buffer);
let checksum_at = buffer.len() - 4;
let checksum = crc::crc32::checksum_ieee(&reader.get_ref()[0..checksum_at]);
reader.set_position(checksum_at);
if reader.read_u32()? != checksum {
return Err(Error::CorruptedPacket)
}
reader.set_position(0);
Ok(Packet::read_from(&mut reader)?)
})
}
pub fn recv_timeout(linkno: u8, timeout_ms: Option<u64>) -> Result<Packet, Error<!>> {
let timeout_ms = timeout_ms.unwrap_or(10);
let limit = clock::get_ms() + timeout_ms;
while clock::get_ms() < limit {
match recv(linkno)? {
None => (),
Some(packet) => return Ok(packet),
}
}
Err(Error::TimedOut)
}
fn transmit<F>(linkno: u8, f: F) -> Result<(), Error<!>>
where F: FnOnce(&mut [u8]) -> Result<usize, Error<!>>
{
let linkno = linkno as usize;
unsafe {
while (DRTIOAUX[linkno].aux_tx_read)() != 0 {}
let ptr = DRTIOAUX_MEM[linkno].base;
let len = DRTIOAUX_MEM[linkno].size / 2;
let len = f(slice::from_raw_parts_mut(ptr as *mut u8, len))?;
(DRTIOAUX[linkno].aux_tx_length_write)(len as u16);
(DRTIOAUX[linkno].aux_tx_write)(1);
Ok(())
}
}
pub fn send(linkno: u8, packet: &Packet) -> Result<(), Error<!>> {
transmit(linkno, |buffer| {
let mut writer = Cursor::new(buffer);
packet.write_to(&mut writer)?;
// Pad till offset 4, insert checksum there
let padding = (12 - (writer.position() % 8)) % 8;
for _ in 0..padding {
writer.write_u8(0)?;
}
let checksum = crc::crc32::checksum_ieee(&writer.get_ref()[0..writer.position()]);
writer.write_u32(checksum)?;
Ok(writer.position())
})
}