f50cd85c84
Add traits that let client cast typecast safely between object types. In particular, an upcast is compile-time guaranteed to succeed, and a YOLO C-style downcast must be marked as unsafe. The traits are based on an IsA<> trait that declares what is a subclass of what, which is an idea taken from glib-rs (https://docs.rs/glib/latest/glib/object/trait.IsA.html). The four primitives are also taken from there (https://docs.rs/glib/latest/glib/object/trait.Cast.html). However, the implementation of casting itself is a bit different and uses the Deref trait. This removes some pointer arithmetic from the pl011 device; it is also a prerequisite for the definition of methods, so that they can be invoked on all subclass structs. This will use the IsA<> trait to detect the structs that support the methods. glib also has a "monadic" casting trait which could be implemented on Option (as in https://docs.rs/glib/latest/glib/object/trait.CastNone.html) and perhaps even Result. For now I'm leaving it out, as the patch is already big enough and the benefit seems debatable. Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
51 lines
1.5 KiB
Rust
51 lines
1.5 KiB
Rust
// Copyright 2024 Red Hat, Inc.
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// Author(s): Paolo Bonzini <pbonzini@redhat.com>
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// SPDX-License-Identifier: GPL-2.0-or-later
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use std::{ffi::CStr, ptr::addr_of};
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pub use bindings::{SysBusDevice, SysBusDeviceClass};
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use crate::{
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bindings,
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cell::bql_locked,
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irq::InterruptSource,
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prelude::*,
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qdev::{DeviceClass, DeviceState},
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qom::ClassInitImpl,
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};
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unsafe impl ObjectType for SysBusDevice {
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type Class = SysBusDeviceClass;
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const TYPE_NAME: &'static CStr =
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unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_SYS_BUS_DEVICE) };
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}
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qom_isa!(SysBusDevice: DeviceState, Object);
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// TODO: add SysBusDeviceImpl
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impl<T> ClassInitImpl<SysBusDeviceClass> for T
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where
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T: ClassInitImpl<DeviceClass>,
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{
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fn class_init(sdc: &mut SysBusDeviceClass) {
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<T as ClassInitImpl<DeviceClass>>::class_init(&mut sdc.parent_class);
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}
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}
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impl SysBusDevice {
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/// Return `self` cast to a mutable pointer, for use in calls to C code.
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const fn as_mut_ptr(&self) -> *mut SysBusDevice {
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addr_of!(*self) as *mut _
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}
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/// Expose an interrupt source outside the device as a qdev GPIO output.
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/// Note that the ordering of calls to `init_irq` is important, since
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/// whoever creates the sysbus device will refer to the interrupts with
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/// a number that corresponds to the order of calls to `init_irq`.
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pub fn init_irq(&self, irq: &InterruptSource) {
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assert!(bql_locked());
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unsafe {
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bindings::sysbus_init_irq(self.as_mut_ptr(), irq.as_ptr());
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}
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}
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}
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