1 // Copyright 2024, Linaro Limited 2 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org> 3 // SPDX-License-Identifier: GPL-2.0-or-later 4 5 use std::ffi::CStr; 6 7 use crate::{ 8 bindings::{self, DeviceClass, DeviceState, Error, Property, VMStateDescription}, 9 definitions::ClassInitImpl, 10 prelude::*, 11 }; 12 13 /// Trait providing the contents of [`DeviceClass`]. 14 pub trait DeviceImpl { 15 /// _Realization_ is the second stage of device creation. It contains 16 /// all operations that depend on device properties and can fail (note: 17 /// this is not yet supported for Rust devices). 18 /// 19 /// If not `None`, the parent class's `realize` method is overridden 20 /// with the function pointed to by `REALIZE`. 21 const REALIZE: Option<fn(&mut Self)> = None; 22 23 /// If not `None`, the parent class's `reset` method is overridden 24 /// with the function pointed to by `RESET`. 25 /// 26 /// Rust does not yet support the three-phase reset protocol; this is 27 /// usually okay for leaf classes. 28 const RESET: Option<fn(&mut Self)> = None; 29 30 /// An array providing the properties that the user can set on the 31 /// device. Not a `const` because referencing statics in constants 32 /// is unstable until Rust 1.83.0. 33 fn properties() -> &'static [Property] { 34 &[] 35 } 36 37 /// A `VMStateDescription` providing the migration format for the device 38 /// Not a `const` because referencing statics in constants is unstable 39 /// until Rust 1.83.0. 40 fn vmsd() -> Option<&'static VMStateDescription> { 41 None 42 } 43 } 44 45 /// # Safety 46 /// 47 /// This function is only called through the QOM machinery and 48 /// used by the `ClassInitImpl<DeviceClass>` trait. 49 /// We expect the FFI user of this function to pass a valid pointer that 50 /// can be downcasted to type `T`. We also expect the device is 51 /// readable/writeable from one thread at any time. 52 unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp: *mut *mut Error) { 53 assert!(!dev.is_null()); 54 let state = dev.cast::<T>(); 55 T::REALIZE.unwrap()(unsafe { &mut *state }); 56 } 57 58 /// # Safety 59 /// 60 /// We expect the FFI user of this function to pass a valid pointer that 61 /// can be downcasted to type `T`. We also expect the device is 62 /// readable/writeable from one thread at any time. 63 unsafe extern "C" fn rust_reset_fn<T: DeviceImpl>(dev: *mut DeviceState) { 64 assert!(!dev.is_null()); 65 let state = dev.cast::<T>(); 66 T::RESET.unwrap()(unsafe { &mut *state }); 67 } 68 69 impl<T> ClassInitImpl<DeviceClass> for T 70 where 71 T: DeviceImpl, 72 { 73 fn class_init(dc: &mut DeviceClass) { 74 if <T as DeviceImpl>::REALIZE.is_some() { 75 dc.realize = Some(rust_realize_fn::<T>); 76 } 77 if <T as DeviceImpl>::RESET.is_some() { 78 unsafe { 79 bindings::device_class_set_legacy_reset(dc, Some(rust_reset_fn::<T>)); 80 } 81 } 82 if let Some(vmsd) = <T as DeviceImpl>::vmsd() { 83 dc.vmsd = vmsd; 84 } 85 let prop = <T as DeviceImpl>::properties(); 86 if !prop.is_empty() { 87 unsafe { 88 bindings::device_class_set_props_n(dc, prop.as_ptr(), prop.len()); 89 } 90 } 91 } 92 } 93 94 #[macro_export] 95 macro_rules! define_property { 96 ($name:expr, $state:ty, $field:ident, $prop:expr, $type:ty, default = $defval:expr$(,)*) => { 97 $crate::bindings::Property { 98 // use associated function syntax for type checking 99 name: ::std::ffi::CStr::as_ptr($name), 100 info: $prop, 101 offset: $crate::offset_of!($state, $field) as isize, 102 set_default: true, 103 defval: $crate::bindings::Property__bindgen_ty_1 { u: $defval as u64 }, 104 ..$crate::zeroable::Zeroable::ZERO 105 } 106 }; 107 ($name:expr, $state:ty, $field:ident, $prop:expr, $type:ty$(,)*) => { 108 $crate::bindings::Property { 109 // use associated function syntax for type checking 110 name: ::std::ffi::CStr::as_ptr($name), 111 info: $prop, 112 offset: $crate::offset_of!($state, $field) as isize, 113 set_default: false, 114 ..$crate::zeroable::Zeroable::ZERO 115 } 116 }; 117 } 118 119 #[macro_export] 120 macro_rules! declare_properties { 121 ($ident:ident, $($prop:expr),*$(,)*) => { 122 pub static $ident: [$crate::bindings::Property; { 123 let mut len = 0; 124 $({ 125 _ = stringify!($prop); 126 len += 1; 127 })* 128 len 129 }] = [ 130 $($prop),*, 131 ]; 132 }; 133 } 134 135 unsafe impl ObjectType for DeviceState { 136 type Class = DeviceClass; 137 const TYPE_NAME: &'static CStr = 138 unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_DEVICE) }; 139 } 140