Merge pull request #1239 from hermit-os/interrupt-status

refactor(virtio/mmio): migrate `IsrStatusRaw` to `virtio-spec`

src/drivers/virtio/transport/mmio.rs

@@ -3,11 +3,12 @@
 //! The module contains ...
 #![allow(dead_code)]
 
-use core::ptr::{read_volatile, write_volatile};
+use core::mem;
 use core::sync::atomic::{fence, Ordering};
 
 use virtio_spec::mmio::{
 	DeviceRegisterVolatileFieldAccess, DeviceRegisterVolatileWideFieldAccess, DeviceRegisters,
+	InterruptStatus,
 };
 use virtio_spec::DeviceStatus;
 use volatile::VolatileRef;
@@ -380,56 +381,47 @@ impl NotifCtrl {
 	}
 }
 
-/// Wraps a [IsrStatusRaw] in order to preserve
+/// Wraps a [`DeviceRegisters`] in order to preserve
 /// the original structure and allow interaction with the device via
 /// the structure.
 ///
 /// Provides a safe API for Raw structure and allows interaction with the device via
 /// the structure.
 pub struct IsrStatus {
-	raw: &'static mut IsrStatusRaw,
+	// FIXME: integrate into device register struct
+	raw: VolatileRef<'static, DeviceRegisters>,
 }
 
 impl IsrStatus {
-	pub fn new(mut registers: VolatileRef<'_, DeviceRegisters>) -> Self {
-		let ptr = registers
-			.as_mut_ptr()
-			.interrupt_status()
-			.as_raw_ptr()
-			.as_ptr();
-		let raw: &'static mut IsrStatusRaw = unsafe { &mut *(ptr as *mut IsrStatusRaw) };
-
-		IsrStatus { raw }
+	pub fn new(registers: VolatileRef<'_, DeviceRegisters>) -> Self {
+		let raw =
+			unsafe { mem::transmute::<VolatileRef<'_, _>, VolatileRef<'static, _>>(registers) };
+		Self { raw }
 	}
 
 	pub fn is_interrupt(&self) -> bool {
-		unsafe {
-			let status = read_volatile(&self.raw.interrupt_status);
-			status & 0x1 == 0x1
-		}
+		self.raw
+			.as_ptr()
+			.interrupt_status()
+			.read()
+			.contains(InterruptStatus::USED_BUFFER_NOTIFICATION)
 	}
 
 	pub fn is_cfg_change(&self) -> bool {
-		unsafe {
-			let status = read_volatile(&self.raw.interrupt_status);
-			status & 0x2 == 0x2
-		}
+		self.raw
+			.as_ptr()
+			.interrupt_status()
+			.read()
+			.contains(InterruptStatus::CONFIGURATION_CHANGE_NOTIFICATION)
 	}
 
 	pub fn acknowledge(&mut self) {
-		unsafe {
-			let status = read_volatile(&self.raw.interrupt_status);
-			write_volatile(&mut self.raw.interrupt_ack, status);
-		}
+		let ptr = self.raw.as_mut_ptr();
+		let status = ptr.interrupt_status().read();
+		ptr.interrupt_ack().write(status);
 	}
 }
 
-#[repr(C)]
-struct IsrStatusRaw {
-	interrupt_status: u32,
-	interrupt_ack: u32,
-}
-
 pub(crate) enum VirtioDriver {
 	#[cfg(any(feature = "tcp", feature = "udp"))]
 	Network(VirtioNetDriver),

virtio-spec/src/mmio.rs

@@ -272,19 +272,10 @@ device_register_impl! {
         ///
         /// Reading from this register returns a bit mask of events that
         /// caused the device interrupt to be asserted.
-        /// The following events are possible:
-        ///
-        /// - Used Buffer Notification
-        ///     - bit 0 - the interrupt was asserted
-        ///     because the device has used a buffer
-        ///     in at least one of the active virtual queues.
-        /// - Configuration Change Notification
-        ///     - bit 1 - the interrupt was
-        ///     asserted because the configuration of the device has changed.
         #[doc(alias = "InterruptStatus")]
         #[offset(0x060)]
         #[access(ReadOnly)]
-        interrupt_status: le32,
+        interrupt_status: InterruptStatus,
 
         /// Interrupt acknowledge
         ///
@@ -294,7 +285,7 @@ device_register_impl! {
         #[doc(alias = "InterruptACK")]
         #[offset(0x064)]
         #[access(WriteOnly)]
-        interrupt_ack: le32,
+        interrupt_ack: InterruptStatus,
 
         /// Device status
         ///
@@ -528,3 +519,18 @@ impl_wide_field_access! {
         shm_base: shm_base_low, shm_base_high;
     }
 }
+
+virtio_bitflags! {
+    /// Interrupt Status
+    pub struct InterruptStatus: u8 {
+        /// Used Buffer Notification
+        ///
+        /// The interrupt was asserted because the device has used a buffer in at least one of the active virtual queues.
+        const USED_BUFFER_NOTIFICATION = 1 << 0;
+
+        /// Configuration Change Notification
+        ///
+        /// The interrupt was asserted because the configuration of the device has changed.
+        const CONFIGURATION_CHANGE_NOTIFICATION = 1 << 1;
+    }
+}

virtio-spec/src/volatile.rs

@@ -5,6 +5,7 @@ use core::marker::PhantomData;
 use volatile::access::{Readable, Writable};
 use volatile::VolatilePtr;
 
+use crate::mmio::InterruptStatus;
 use crate::{be32, be64, le16, le32, le64, DeviceStatus};
 
 /// A wide volatile pointer for 64-bit fields.
@@ -272,7 +273,18 @@ impl OveralignedField<le32> for DeviceStatus {
     }
 }
 
+impl OveralignedField<le32> for InterruptStatus {
+    fn from_field(field: le32) -> Self {
+        Self::from_bits_retain(u8::from_field(field))
+    }
+
+    fn into_field(self) -> le32 {
+        self.bits().into_field()
+    }
+}
+
 mod private {
+    use crate::mmio::InterruptStatus;
     use crate::{le16, le32, DeviceStatus};
 
     pub trait Sealed<T> {}
@@ -281,4 +293,5 @@ mod private {
     impl Sealed<le32> for u8 {}
     impl Sealed<le32> for le16 {}
     impl Sealed<le32> for DeviceStatus {}
+    impl Sealed<le32> for InterruptStatus {}
 }