1 files changed, 122 insertions, 0 deletions
diff --git a/rust/hw/core/src/sysbus.rs b/rust/hw/core/src/sysbus.rs
new file mode 100644
index 0000000000..dda71ebda7
--- /dev/null
+++ b/rust/hw/core/src/sysbus.rs
@@ -0,0 +1,122 @@
+// Copyright 2024 Red Hat, Inc.
+// Author(s): Paolo Bonzini <pbonzini@redhat.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Bindings to access `sysbus` functionality from Rust.
+
+use std::{ffi::CStr, ptr::addr_of_mut};
+
+pub use bindings::SysBusDeviceClass;
+use common::Opaque;
+use qom::{prelude::*, Owned};
+use system::MemoryRegion;
+
+use crate::{
+    bindings,
+    irq::{IRQState, InterruptSource},
+    qdev::{DeviceImpl, DeviceState},
+};
+
+/// A safe wrapper around [`bindings::SysBusDevice`].
+#[repr(transparent)]
+#[derive(Debug, qemu_api_macros::Wrapper)]
+pub struct SysBusDevice(Opaque<bindings::SysBusDevice>);
+
+unsafe impl Send for SysBusDevice {}
+unsafe impl Sync for SysBusDevice {}
+
+unsafe impl ObjectType for SysBusDevice {
+    type Class = SysBusDeviceClass;
+    const TYPE_NAME: &'static CStr =
+        unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_SYS_BUS_DEVICE) };
+}
+
+qom_isa!(SysBusDevice: DeviceState, Object);
+
+// TODO: add virtual methods
+pub trait SysBusDeviceImpl: DeviceImpl + IsA<SysBusDevice> {}
+
+impl SysBusDeviceClass {
+    /// Fill in the virtual methods of `SysBusDeviceClass` based on the
+    /// definitions in the `SysBusDeviceImpl` trait.
+    pub fn class_init<T: SysBusDeviceImpl>(self: &mut SysBusDeviceClass) {
+        self.parent_class.class_init::<T>();
+    }
+}
+
+/// Trait for methods of [`SysBusDevice`] and its subclasses.
+pub trait SysBusDeviceMethods: ObjectDeref
+where
+    Self::Target: IsA<SysBusDevice>,
+{
+    /// Expose a memory region to the board so that it can give it an address
+    /// in guest memory.  Note that the ordering of calls to `init_mmio` is
+    /// important, since whoever creates the sysbus device will refer to the
+    /// region with a number that corresponds to the order of calls to
+    /// `init_mmio`.
+    fn init_mmio(&self, iomem: &MemoryRegion) {
+        assert!(bql::is_locked());
+        unsafe {
+            bindings::sysbus_init_mmio(self.upcast().as_mut_ptr(), iomem.as_mut_ptr());
+        }
+    }
+
+    /// Expose an interrupt source outside the device as a qdev GPIO output.
+    /// Note that the ordering of calls to `init_irq` is important, since
+    /// whoever creates the sysbus device will refer to the interrupts with
+    /// a number that corresponds to the order of calls to `init_irq`.
+    fn init_irq(&self, irq: &InterruptSource) {
+        assert!(bql::is_locked());
+        unsafe {
+            bindings::sysbus_init_irq(self.upcast().as_mut_ptr(), irq.as_ptr());
+        }
+    }
+
+    // TODO: do we want a type like GuestAddress here?
+    fn mmio_addr(&self, id: u32) -> Option<u64> {
+        assert!(bql::is_locked());
+        // SAFETY: the BQL ensures that no one else writes to sbd.mmio[], and
+        // the SysBusDevice must be initialized to get an IsA<SysBusDevice>.
+        let sbd = unsafe { *self.upcast().as_ptr() };
+        let id: usize = id.try_into().unwrap();
+        if sbd.mmio[id].memory.is_null() {
+            None
+        } else {
+            Some(sbd.mmio[id].addr)
+        }
+    }
+
+    // TODO: do we want a type like GuestAddress here?
+    fn mmio_map(&self, id: u32, addr: u64) {
+        assert!(bql::is_locked());
+        let id: i32 = id.try_into().unwrap();
+        unsafe {
+            bindings::sysbus_mmio_map(self.upcast().as_mut_ptr(), id, addr);
+        }
+    }
+
+    // Owned<> is used here because sysbus_connect_irq (via
+    // object_property_set_link) adds a reference to the IRQState,
+    // which can prolong its life
+    fn connect_irq(&self, id: u32, irq: &Owned<IRQState>) {
+        assert!(bql::is_locked());
+        let id: i32 = id.try_into().unwrap();
+        let irq: &IRQState = irq;
+        unsafe {
+            bindings::sysbus_connect_irq(self.upcast().as_mut_ptr(), id, irq.as_mut_ptr());
+        }
+    }
+
+    fn sysbus_realize(&self) {
+        // TODO: return an Error
+        assert!(bql::is_locked());
+        unsafe {
+            bindings::sysbus_realize(
+                self.upcast().as_mut_ptr(),
+                addr_of_mut!(util::bindings::error_fatal),
+            );
+        }
+    }
+}
+
+impl<R: ObjectDeref> SysBusDeviceMethods for R where R::Target: IsA<SysBusDevice> {}