Short-circuit out of NAK on interrupt pipes.

Don't bother retrying. NAK on an interrupt endpoint means there's no
data.

2 files changed, 14 insertions, 8 deletions

diff --git a/usbh/src/device.rs b/usbh/src/device.rs
index aba3919..fd5c1a1 100644
--- a/usbh/src/device.rs
+++ b/usbh/src/device.rs
@@ -302,7 +302,7 @@ impl Device {
             FSM::GetReport(0) => self.state = FSM::Steady,
 
             FSM::GetReport(count) => {
-                info!("+++ getting report {}", count);
+                debug!("+++ getting report {}", count);
 
                 // For now, just do an IN transfer to see if we can
                 // get some keyboard reports without further setup.
@@ -324,12 +324,11 @@ impl Device {
     fn read_report(&mut self, pipe_table: &mut PipeTable, host: &mut usb::HOST, id: u8) {
         if let Some(ref mut ep) = self.endpoints[id as usize] {
             let mut pipe = pipe_table.pipe_for(host, ep);
-            let mut buf: core::mem::MaybeUninit<[u8; 8]> = core::mem::MaybeUninit::uninit();
+            let mut buf: [u8; 8] = [0; 8];
             match pipe.in_transfer(ep, &mut buf, 15, self.millis) {
-                Ok(bytes_received) => {
-                    let tmp = unsafe { &(buf.assume_init())[..bytes_received] };
-                    info!("report {}: {:?}", id, tmp);
-                }
+                Ok(bytes_received) => info!("report {}: {} - {:?}", id, bytes_received, buf),
+
+                Err(PipeErr::Flow) => return,
 
                 Err(e) => trace!("error {}: {:?}", id, e),
             }
diff --git a/usbh/src/pipe.rs b/usbh/src/pipe.rs
index abdba2a..80ebe11 100644
--- a/usbh/src/pipe.rs
+++ b/usbh/src/pipe.rs
@@ -321,9 +321,9 @@ impl Pipe<'_, '_> {
             ep.out_toggle,
         );
         if self.regs.status.read().dtgl().bit_is_set() {
-            self.dtgl_clear();
-        } else {
             self.dtgl_set();
+        } else {
+            self.dtgl_clear();
         }
         if token == PToken::In {
             ep.in_toggle = self.regs.status.read().dtgl().bit_is_set()
@@ -377,6 +377,13 @@ impl Pipe<'_, '_> {
                     last_err = e;
                     match last_err {
                         PipeErr::DataToggle => self.dtgl(ep, token),
+
+                        // Flow error on interrupt pipes means we got
+                        // a NAK, which in this context means there's
+                        // no data. cf §32.8.7.5 of SAM D21 data
+                        // sheet.
+                        PipeErr::Flow if ep.transfer_type == TransferType::Interrupt => break,
+
                         PipeErr::Stall => break,
                         _ => {
                             naks += 1;