redbear-acmd: fix global endpoint indexing; add serial-state monitor + SEND_BREAK (P6-A)

Bug fix: endpoint numbers were computed as per-interface positions, but
xhcid keys endpoints by GLOBAL index across all interfaces of the
configuration. On two-interface ACM devices (comm interrupt-IN first),
the driver opened (interrupt-IN, bulk-IN) as (bulk_in, bulk_out) — read
from the interrupt endpoint and wrote to the IN endpoint. Endpoints are
now counted across all interfaces in configuration order, exactly as
xhcid's PortState::get_endp_desc does.

P6-A expansion (Linux 7.1 cdc-acm.c reference):
- SEND_BREAK (0x23) control request
- SERIAL_STATE monitoring: poll the comm interface's interrupt-IN
  endpoint on a dedicated thread, parse the 8-byte header + 2-byte UART
  state bitmap (CDC 1.1 6.3.5): DCD/DSR/break/RI/framing/parity/overrun,
  log transitions
- scheme gains a read-only 'state' file reporting the current line
  state (dcd=.. dsr=.. ...) for getty/terminal consumers

Verified: cargo check -Z build-std --target x86_64-unknown-redox clean,
no new warnings. Runtime validation needs an ACM device (QEMU has no
CDC ACM emulation; FTDI/Arduino on bare metal or passed through).
This commit is contained in:
2026-07-20 20:59:16 +09:00
parent cd9b225e39
commit f505d18a89
2 changed files with 152 additions and 14 deletions
@@ -21,9 +21,49 @@ use xhcid_interface::{
const SET_LINE_CODING: u8 = 0x20;
const GET_LINE_CODING: u8 = 0x21;
const SET_CONTROL_LINE_STATE: u8 = 0x22;
const SEND_BREAK: u8 = 0x23;
const CTRL_DTR: u16 = 1 << 0;
const CTRL_RTS: u16 = 1 << 1;
/// CDC ACM class codes.
const CDC_COMM_CLASS: u8 = 0x02;
const CDC_DATA_CLASS: u8 = 0x0A;
/// UART state bitmap from the CDC SERIAL_STATE notification
/// (CDC spec 1.1 section 6.3.5, table 69).
#[derive(Clone, Copy, Debug, Default)]
pub struct SerialState {
pub dcd: bool,
pub dsr: bool,
pub break_detected: bool,
pub ring: bool,
pub framing_error: bool,
pub parity_error: bool,
pub overrun: bool,
}
impl SerialState {
fn from_uart_state_bits(bits: u16) -> Self {
Self {
dcd: bits & (1 << 0) != 0,
dsr: bits & (1 << 1) != 0,
break_detected: bits & (1 << 2) != 0,
ring: bits & (1 << 3) != 0,
framing_error: bits & (1 << 4) != 0,
parity_error: bits & (1 << 5) != 0,
overrun: bits & (1 << 6) != 0,
}
}
pub fn to_display(&self) -> String {
format!(
"dcd={} dsr={} break={} ri={} framing={} parity={} overrun={}\n",
self.dcd as u8, self.dsr as u8, self.break_detected as u8,
self.ring as u8, self.framing_error as u8, self.parity_error as u8,
self.overrun as u8
)
}
}
#[repr(C, packed)]
#[derive(Clone, Copy, Debug, Default)]
struct LineCoding { dw_dte_rate: u32, b_char_format: u8, b_parity_type: u8, b_data_bits: u8 }
@@ -50,6 +90,43 @@ impl AcmDevice {
fn set_control_line_state(&mut self, state: u16) -> Result<(), io::Error> {
self.cdc_ctrl_msg(SET_CONTROL_LINE_STATE, state, DeviceReqData::NoData)
}
/// SEND_BREAK (CDC ACM 6.3.4): assert a break condition for `duration_ms`
/// (0xFFFF = indefinite, 0 = stop).
fn send_break(&mut self, duration_ms: u16) -> Result<(), io::Error> {
self.cdc_ctrl_msg(SEND_BREAK, duration_ms, DeviceReqData::NoData)
}
}
/// SERIAL_STATE notification header size (8-byte setup-style header) plus the
/// 2-byte UART state bitmap (CDC spec 1.1 section 6.3.5).
const SERIAL_STATE_LEN: usize = 10;
/// Poll the comm interface's interrupt-IN endpoint for SERIAL_STATE
/// notifications and keep `state` current. Runs for the life of the driver.
fn serial_state_monitor(mut int_in: XhciEndpHandle, state: std::sync::Arc<std::sync::Mutex<SerialState>>) {
let mut buf = [0u8; SERIAL_STATE_LEN];
loop {
match int_in.transfer_read(&mut buf) {
Ok(s) if s.bytes_transferred as usize >= SERIAL_STATE_LEN => {
// bmRequestType 0xA1, bNotification 0x20 (SERIAL_STATE),
// wLength 2; UART state bitmap at bytes 8-9 (LE).
if buf[0] == 0xA1 && buf[1] == 0x20 {
let bits = u16::from_le_bytes([buf[8], buf[9]]);
let new_state = SerialState::from_uart_state_bits(bits);
let mut guard = state.lock().unwrap_or_else(|e| e.into_inner());
if new_state.to_display() != guard.to_display() {
log::info!("CDC ACM: serial state: {}", new_state.to_display().trim_end());
*guard = new_state;
}
}
}
Ok(_) => {}
Err(e) => {
log::warn!("CDC ACM: serial-state interrupt read: {}", e);
thread::sleep(time::Duration::from_millis(100));
}
}
}
}
fn main() {
@@ -64,18 +141,37 @@ fn main() {
let handle = XhciClientHandle::new(scheme.clone(), port_id).expect("xhci");
let desc: DevDesc = handle.get_standard_descs().expect("descriptors");
let (conf_desc, data_if) = desc.config_descs.iter()
.find_map(|c| c.interface_descs.iter().find(|i| i.class == 0x0A).map(|d| (c.clone(), d.clone())))
.find_map(|c| c.interface_descs.iter().find(|i| i.class == CDC_DATA_CLASS).map(|d| (c.clone(), d.clone())))
.expect("No CDC ACM data interface");
handle.configure_endpoints(&ConfigureEndpointsReq {
config_desc: conf_desc.configuration_value, interface_desc: Some(data_if.number),
alternate_setting: Some(data_if.alternate_setting), hub_ports: None,
}).expect("config");
let bulk_in_num = data_if.endpoints.iter()
.position(|ep| ep.direction() == EndpDirection::In && ep.ty() == EndpointTy::Bulk)
.map(|i| (i + 1) as u8).expect("bulk IN");
let bulk_out_num = data_if.endpoints.iter()
.position(|ep| ep.direction() == EndpDirection::Out && ep.ty() == EndpointTy::Bulk)
.map(|i| (i + 1) as u8).expect("bulk OUT");
// xhcid keys endpoints by GLOBAL index across all interfaces of the
// configuration (see xhcid PortState::get_endp_desc / endpoint_states).
// Counting per-interface positions instead opens the wrong endpoints on
// two-interface ACM devices: with the comm interface's interrupt endpoint
// first, per-interface positions (1, 2) hit (interrupt-IN, bulk-IN) while
// the real bulk endpoints are (2, 3). Count across all interfaces in
// configuration order, exactly as xhcid does.
let mut bulk_in_num = None;
let mut bulk_out_num = None;
let mut int_in_num = None;
let mut global_num = 0u8;
for if_desc in conf_desc.interface_descs.iter() {
for ep in if_desc.endpoints.iter() {
global_num += 1;
match (ep.direction(), ep.ty(), if_desc.class) {
(EndpDirection::In, EndpointTy::Bulk, CDC_DATA_CLASS) => bulk_in_num = Some(global_num),
(EndpDirection::Out, EndpointTy::Bulk, CDC_DATA_CLASS) => bulk_out_num = Some(global_num),
(EndpDirection::In, EndpointTy::Interrupt, CDC_COMM_CLASS) => int_in_num = Some(global_num),
_ => {}
}
}
}
let bulk_in_num = bulk_in_num.expect("bulk IN");
let bulk_out_num = bulk_out_num.expect("bulk OUT");
let mut dev = AcmDevice {
bulk_in: handle.open_endpoint(bulk_in_num).expect("open IN"),
bulk_out: handle.open_endpoint(bulk_out_num).expect("open OUT"),
@@ -85,6 +181,21 @@ fn main() {
let _ = dev.set_line_coding(&lc);
let _ = dev.set_control_line_state(CTRL_DTR | CTRL_RTS);
// SERIAL_STATE monitoring on the comm interface's interrupt-IN endpoint
// (P6-A): DCD/DSR/break/RI/error bits, exposed via the scheme's "state"
// file. Devices without a comm interrupt endpoint simply report the
// default zero state.
let serial_state = std::sync::Arc::new(std::sync::Mutex::new(SerialState::default()));
if let Some(int_num) = int_in_num {
match dev.handle.open_endpoint(int_num) {
Ok(int_in) => {
let state_clone = std::sync::Arc::clone(&serial_state);
thread::spawn(move || serial_state_monitor(int_in, state_clone));
}
Err(err) => log::warn!("CDC ACM: failed to open interrupt endpoint {}: {}", int_num, err),
}
}
// ── Scheme IPC path (Redox) ──
#[cfg(target_os = "redox")]
{
@@ -94,7 +205,11 @@ fn main() {
log::info!("CDC ACM: registering /scheme/{}", scheme_name);
let socket = Socket::create().expect("CDC ACM: scheme socket");
let mut scheme_state = redox_scheme::scheme::SchemeState::new();
let mut acm_scheme = crate::scheme::AcmScheme::new(dev.bulk_in, dev.bulk_out);
let mut acm_scheme = crate::scheme::AcmScheme::new(
dev.bulk_in,
dev.bulk_out,
std::sync::Arc::clone(&serial_state),
);
let _ = libredox::call::setrens(0, 0);
log::info!("CDC ACM: scheme /scheme/{} ready", scheme_name);
loop {
@@ -1,4 +1,4 @@
use std::sync::Mutex;
use std::sync::{Arc, Mutex};
use redox_scheme::scheme::SchemeSync;
use redox_scheme::{CallerCtx, OpenResult};
@@ -8,31 +8,54 @@ use syscall::schemev2::NewFdFlags;
use xhcid_interface::XhciEndpHandle;
use crate::SerialState;
/// Scheme fd number for the read-only "state" file (serial line state).
const STATE_FD: usize = 2;
pub struct AcmScheme {
bulk_in: Mutex<XhciEndpHandle>,
bulk_out: Mutex<XhciEndpHandle>,
serial_state: Arc<Mutex<SerialState>>,
open_count: Mutex<usize>,
}
impl AcmScheme {
pub fn new(bulk_in: XhciEndpHandle, bulk_out: XhciEndpHandle) -> Self {
Self { bulk_in: Mutex::new(bulk_in), bulk_out: Mutex::new(bulk_out), open_count: Mutex::new(0) }
pub fn new(bulk_in: XhciEndpHandle, bulk_out: XhciEndpHandle, serial_state: Arc<Mutex<SerialState>>) -> Self {
Self {
bulk_in: Mutex::new(bulk_in),
bulk_out: Mutex::new(bulk_out),
serial_state,
open_count: Mutex::new(0),
}
}
}
impl SchemeSync for AcmScheme {
fn openat(&mut self, fd: usize, path: &str, _flags: usize, _fcntl_flags: u32, _ctx: &CallerCtx) -> Result<OpenResult> {
if fd != 1 { return Err(Error::new(EBADF)); }
if path == "state" {
return Ok(OpenResult::ThisScheme { number: STATE_FD, flags: NewFdFlags::from_bits_truncate(O_STAT as u8) });
}
if path.is_empty() || path == "." || path == "/" {
*self.open_count.lock().unwrap_or_else(|e| e.into_inner()) += 1;
return Ok(OpenResult::ThisScheme { number: 1, flags: NewFdFlags::from_bits_truncate(O_STAT as u8) });
}
let mut count = self.open_count.lock().unwrap_or_else(|e| e.into_inner());
let next_id = 2 + *count; *count += 1;
let next_id = 3 + *count; *count += 1;
Ok(OpenResult::OtherScheme { fd: next_id })
}
fn read(&mut self, id: usize, buf: &mut [u8], _offset: u64, _fcntl_flags: u32, _ctx: &CallerCtx) -> Result<usize> {
if id < 2 || buf.is_empty() { return Err(Error::new(EBADF)); }
if buf.is_empty() { return Err(Error::new(EBADF)); }
if id == STATE_FD {
let state = self.serial_state.lock().unwrap_or_else(|e| e.into_inner());
let text = state.to_display();
let bytes = text.as_bytes();
let n = bytes.len().min(buf.len());
buf[..n].copy_from_slice(&bytes[..n]);
return Ok(n);
}
if id < 3 { return Err(Error::new(EBADF)); }
let mut bulk_in = self.bulk_in.lock().unwrap_or_else(|e| e.into_inner());
match bulk_in.transfer_read(buf) {
Ok(status) if status.bytes_transferred > 0 => Ok(status.bytes_transferred as usize),
@@ -41,7 +64,7 @@ impl SchemeSync for AcmScheme {
}
}
fn write(&mut self, id: usize, buf: &[u8], _offset: u64, _fcntl_flags: u32, _ctx: &CallerCtx) -> Result<usize> {
if id < 2 || buf.is_empty() { return Err(Error::new(EBADF)); }
if id < 3 || buf.is_empty() { return Err(Error::new(EBADF)); }
let mut bulk_out = self.bulk_out.lock().unwrap_or_else(|e| e.into_inner());
match bulk_out.transfer_write(buf) {
Ok(status) if status.bytes_transferred > 0 => Ok(status.bytes_transferred as usize),