server usb cycle update

server/src/usb_gadget.rs

@@ -1,7 +1,7 @@
 // server/src/usb_gadget.rs
 use std::{fs::{self, OpenOptions}, io::Write, thread, time::Duration};
 use anyhow::{Context, Result};
-use tracing::{info, warn};
+use tracing::{info, warn, trace};
 
 #[derive(Clone)]
 pub struct UsbGadget {
@@ -17,59 +17,83 @@ impl UsbGadget {
         }
     }
 
-    /// Read the controller name currently written to `<gadget>/UDC`
-    fn current_udc(&self) -> Result<String> {
-        Ok(fs::read_to_string(self.udc_file)?.trim().to_owned())
-    }
-
-    /// Helper: busy‑loop (max 10s) until the UDC `state` file equals `wanted`.
-    fn wait_state(udc: &str, wanted: &str) -> Result<()> {
-        let state_file = format!("/sys/class/udc/{udc}/state");
-        for _ in 0..100 {
-            let state = fs::read_to_string(&state_file)
-                .unwrap_or_default()
-                .trim()
-                .to_owned();
-            if state == wanted {
-                return Ok(());
-            }
-            thread::sleep(Duration::from_millis(100));
-        }
-        Err(anyhow::anyhow!("🚧 UDC state did not reach '{wanted}' in time"))
-            .with_context(|| format!("waiting for {wanted} in {state_file}"))
-    }
-
-    /// Force the host to re‑enumerate our HID gadget *safely*.
-    pub fn cycle(&self) -> Result<()> {
-        let udc_name = std::fs::read_dir("/sys/class/udc")?
+    /// Return the first UDC name we find, e.g. `1000480000.usb`
+    fn controller() -> Result<String> {
+        Ok(std::fs::read_dir("/sys/class/udc")?
             .next()
             .transpose()?
             .context("no UDC present")?
             .file_name()
             .to_string_lossy()
-            .into_owned();
+            .into_owned())
+    }
 
-        /*–––– DETACH ––––*/
-        if !self.current_udc()?.is_empty() {
-            info!("🔌 UDC‑cycle: detaching gadget");
-            OpenOptions::new()
-                .write(true)
-                .open(self.udc_file)?
-                .write_all(b"")?;
-        } else {
-            info!("🔌 Gadget already detached");
+    /// Read the controller name currently written to `<gadget>/UDC`
+    fn current_udc(&self) -> Result<String> {
+        Ok(fs::read_to_string(self.udc_file)?.trim().to_owned())
+    }
+
+    /// Poll `/sys/class/udc/<name>/state` until it equals `wanted`.
+    fn wait_state(name: &str, wanted: &str, limit_ms: u64) -> Result<()> {
+        let p = format!("/sys/class/udc/{name}/state");
+        let tries = limit_ms / 50;
+        for attempt in 0..tries {
+            let state = fs::read_to_string(&p).unwrap_or_default();
+            if state.trim() == wanted {
+                return Ok(());
+            }
+            trace!("⏳ wait_state polling UDC, retry #{attempt}");
+            thread::sleep(Duration::from_millis(50));
         }
-        Self::wait_state(&udc_name, "not attached")?;
+        Err(anyhow::anyhow!("🚧 UDC never reached '{wanted}' (last state = {:?})", 
+                            fs::read_to_string(&p).unwrap_or_default()))
+    }
 
-        /*–––– ATTACH ––––*/
-        info!("🔌 UDC‑cycle: re‑attaching to {udc_name}");
-        OpenOptions::new()
-            .write(true)
-            .open(self.udc_file)?
-            .write_all(udc_name.as_bytes())?;
+    /// **Hard‑reset** the controller:  
+    ///   1. detach gadget (`UDC=""`)  
+    ///   2. un‑bind driver (`…/drivers/<udc>/unbind`)  
+    ///   3. bind again  
+    ///   4. re‑attach gadget  
+    ///   5. wait until state == `configured`
+    pub fn cycle(&self) -> Result<()> {
+        let ctrl = Self::controller()?;
 
-        Self::wait_state(&udc_name, "configured")?;
-        info!("🔌 USB‑gadget cycled successfully 🎉");
+        /*----- 1. detach gadget from UDC  --------------------------------*/
+        info!("🔌 detaching gadget from controller");
+        OpenOptions::new().write(true).open(self.udc_file)?.write_all(b"")?;
+        Self::wait_state(&ctrl, "not attached", 3_000)
+            .context("waiting for controller to report not‑attached")?;
+
+        /*----- 2./3. unbind / bind the UDC driver  -----------------------*/
+        let drv_dir = "/sys/bus/platform/drivers/dwc2";              // rk35xx & raspi
+        let unbind  = format!("{drv_dir}/unbind");
+        let bind    = format!("{drv_dir}/bind");
+
+        // Some kernels use dwc3 – try that if dwc2 is absent
+        let (unbind, bind) = if std::path::Path::new(&unbind).exists() {
+            (unbind, bind)
+        } else {
+            let d3 = "/sys/bus/platform/drivers/dwc3";
+            (format!("{d3}/unbind"), format!("{d3}/bind"))
+        };
+
+        info!("🔧 unbinding UDC driver");
+        OpenOptions::new().write(true).open(&unbind)?.write_all(ctrl.as_bytes())?;
+        thread::sleep(Duration::from_millis(300));
+
+        info!("🔧 binding   UDC driver");
+        OpenOptions::new().write(true).open(&bind)?.write_all(ctrl.as_bytes())?;
+        thread::sleep(Duration::from_millis(100));
+
+        /*----- 4. re‑attach gadget to controller -------------------------*/
+        info!("🔌 re‑attaching gadget to {ctrl}");
+        OpenOptions::new().write(true).open(self.udc_file)?.write_all(ctrl.as_bytes())?;
+
+        /*----- 5. wait until host finished enumeration -------------------*/
+        Self::wait_state(&ctrl, "configured", 6_000)
+            .context("waiting for host to enumerate gadget")?;
+
+        info!("✅ USB gadget cycle complete; controller back to 'configured'");
         Ok(())
     }
 }