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server udc fix

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This commit is contained in:
Brad Stein 2025-06-26 00:13:32 -05:00
parent 158b9ef3ab
commit a8d843fd2d
1 changed files with 35 additions and 30 deletions
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65
server/src/usb_gadget.rs
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@ -65,43 +65,40 @@ impl UsbGadget {
Err(anyhow::anyhow!("⚠️ UDC {ctrl} did not re‑appear within {limit_ms} ms"))
}
/// Scan platform devices when /sys/class/udc is empty
fn probe_platform_udc() -> Result<Option<String>> {
for entry in fs::read_dir("/sys/bus/platform/devices")? {
let p = entry?.file_name().into_string().unwrap();
if p.ends_with(".usb") { return Ok(Some(p)); }
}
Ok(None)
}
/*–––– public API ––––*/
/// Hard‑reset the gadget → identical to a physical cable re‑plug
pub fn cycle(&self) -> Result<()> {
/* 0 – ensure we *know* the controller even after a previous crash */
let ctrl = match Self::find_controller() {
Ok(c) => c,
Err(_) => {
// try to recover by reading the last name from the gadget’s UDC file
let last = fs::read_to_string(self.udc_file)?.trim().to_owned();
if last.is_empty() {
return Err(anyhow::anyhow!("no UDC present and UDC file is empty"));
}
warn!("⚠️ UDC missing, attempting to re‑bind {last}");
Self::rebind_driver(&last)?;
last
}
};
let mut ctrl = Self::find_controller()
.or_else(|_| Self::probe_platform_udc()?
.ok_or_else(|| anyhow::anyhow!("no UDC present")))?;
/* 1 – detach gadget */
info!("🔌 detaching gadget from {ctrl}");
Self::write_attr(self.udc_file, "")?;
Self::wait_state(&ctrl, "not attached", 3_000)?;
/* 2 – unbind / bind platform driver (dwc2/dwc3) */
/* 2 – reset driver */
Self::rebind_driver(&ctrl)?;
Self::wait_udc_present(&ctrl, 3_000)
.context("controller did not re‑appear after bind")?;
/* 3 – re‑attach gadget */
/* 3 – wait UDC node to re‑appear */
Self::wait_udc_present(&ctrl, 3_000)?;
/* 4 – re‑attach + pull‑up */
info!("🔌 re‑attaching gadget to {ctrl}");
Self::write_attr(self.udc_file, &ctrl)?;
/* 4 – assert pull‑up */
let sc = format!("/sys/class/udc/{ctrl}/soft_connect");
// toggle 0 → 1 to force the controller to assert pull‑ups
Self::write_attr(&sc, "0")?; // guarantee clean edge
Self::write_attr(&sc, "0")?;
thread::sleep(Duration::from_millis(50));
Self::write_attr(&sc, "1")?;
@ -128,20 +125,28 @@ impl UsbGadget {
/// helper: unbind + 300 ms reset + bind
fn rebind_driver(ctrl: &str) -> Result<()> {
let cand = ["dwc2", "dwc3"]; // cover RasPi, RK, AM62, …
let cand = ["dwc2", "dwc3"];
for drv in cand {
let root = format!("/sys/bus/platform/drivers/{drv}");
if !Path::new(&root).exists() {
continue;
}
if !Path::new(&root).exists() { continue }
info!("🔧 unbinding UDC driver ({drv})");
Self::write_attr(format!("{root}/unbind"), ctrl)?;
thread::sleep(Duration::from_millis(500));
let _ = Self::write_attr(format!("{root}/unbind"), ctrl); // ignore EINVAL
thread::sleep(Duration::from_millis(300));
info!("🔧 binding UDC driver ({drv})");
Self::write_attr(format!("{root}/bind"), ctrl)?;
thread::sleep(Duration::from_millis(500));
return Ok(());
for attempt in 1..=10 {
match Self::write_attr(format!("{root}/bind"), ctrl) {
Ok(_) => return Ok(()),
Err(e) if attempt < 10 => {
trace!("bind busy (#{attempt}) – retrying…");
thread::sleep(Duration::from_millis(100));
continue;
}
Err(e) => return Err(e)
.context(format!("bind failed after {attempt} tries")),
}
}
}
Err(anyhow::anyhow!("no dwc2/dwc3 driver nodes found"))
}