Merge pull request #50 from kbleeke/async-ioctls

Rework Ioctls to an async state machine

1 files changed, 111 insertions, 0 deletions

diff --git a/src/ioctl.rs b/src/ioctl.rs
new file mode 100644
index 000000000..6a7465593
--- /dev/null
+++ b/src/ioctl.rs
@@ -0,0 +1,111 @@
+use core::cell::{Cell, RefCell};
+use core::future::poll_fn;
+use core::task::{Poll, Waker};
+
+use embassy_sync::waitqueue::WakerRegistration;
+
+#[derive(Clone, Copy)]
+pub enum IoctlType {
+    Get = 0,
+    Set = 2,
+}
+
+#[derive(Clone, Copy)]
+pub struct PendingIoctl {
+    pub buf: *mut [u8],
+    pub kind: IoctlType,
+    pub cmd: u32,
+    pub iface: u32,
+}
+
+#[derive(Clone, Copy)]
+enum IoctlStateInner {
+    Pending(PendingIoctl),
+    Sent { buf: *mut [u8] },
+    Done { resp_len: usize },
+}
+
+#[derive(Default)]
+struct Wakers {
+    control: WakerRegistration,
+    runner: WakerRegistration,
+}
+
+pub struct IoctlState {
+    state: Cell<IoctlStateInner>,
+    wakers: RefCell<Wakers>,
+}
+
+impl IoctlState {
+    pub fn new() -> Self {
+        Self {
+            state: Cell::new(IoctlStateInner::Done { resp_len: 0 }),
+            wakers: Default::default(),
+        }
+    }
+
+    fn wake_control(&self) {
+        self.wakers.borrow_mut().control.wake();
+    }
+
+    fn register_control(&self, waker: &Waker) {
+        self.wakers.borrow_mut().control.register(waker);
+    }
+
+    fn wake_runner(&self) {
+        self.wakers.borrow_mut().runner.wake();
+    }
+
+    fn register_runner(&self, waker: &Waker) {
+        self.wakers.borrow_mut().runner.register(waker);
+    }
+
+    pub async fn wait_complete(&self) -> usize {
+        poll_fn(|cx| {
+            if let IoctlStateInner::Done { resp_len } = self.state.get() {
+                Poll::Ready(resp_len)
+            } else {
+                self.register_control(cx.waker());
+                Poll::Pending
+            }
+        })
+        .await
+    }
+
+    pub async fn wait_pending(&self) -> PendingIoctl {
+        let pending = poll_fn(|cx| {
+            if let IoctlStateInner::Pending(pending) = self.state.get() {
+                warn!("found pending ioctl");
+                Poll::Ready(pending)
+            } else {
+                self.register_runner(cx.waker());
+                Poll::Pending
+            }
+        })
+        .await;
+
+        self.state.set(IoctlStateInner::Sent { buf: pending.buf });
+        pending
+    }
+
+    pub async fn do_ioctl(&self, kind: IoctlType, cmd: u32, iface: u32, buf: &mut [u8]) -> usize {
+        warn!("doing ioctl");
+        self.state
+            .set(IoctlStateInner::Pending(PendingIoctl { buf, kind, cmd, iface }));
+        self.wake_runner();
+        self.wait_complete().await
+    }
+
+    pub fn ioctl_done(&self, response: &[u8]) {
+        if let IoctlStateInner::Sent { buf } = self.state.get() {
+            warn!("ioctl complete");
+            // TODO fix this
+            (unsafe { &mut *buf }[..response.len()]).copy_from_slice(response);
+
+            self.state.set(IoctlStateInner::Done {
+                resp_len: response.len(),
+            });
+            self.wake_control();
+        }
+    }
+}