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, os::raw::c_void}; 6 7 use crate::{ 8 bindings::{self, DeviceClass, DeviceState, Error, ObjectClass, Property, VMStateDescription}, 9 zeroable::Zeroable, 10 }; 11 12 /// Trait providing the contents of [`DeviceClass`]. 13 pub trait DeviceImpl { 14 /// _Realization_ is the second stage of device creation. It contains 15 /// all operations that depend on device properties and can fail (note: 16 /// this is not yet supported for Rust devices). 17 /// 18 /// If not `None`, the parent class's `realize` method is overridden 19 /// with the function pointed to by `REALIZE`. 20 const REALIZE: Option<fn(&mut Self)> = None; 21 22 /// If not `None`, the parent class's `reset` method is overridden 23 /// with the function pointed to by `RESET`. 24 /// 25 /// Rust does not yet support the three-phase reset protocol; this is 26 /// usually okay for leaf classes. 27 const RESET: Option<fn(&mut Self)> = None; 28 29 /// An array providing the properties that the user can set on the 30 /// device. Not a `const` because referencing statics in constants 31 /// is unstable until Rust 1.83.0. 32 fn properties() -> &'static [Property] { 33 &[Zeroable::ZERO; 1] 34 } 35 36 /// A `VMStateDescription` providing the migration format for the device 37 /// Not a `const` because referencing statics in constants is unstable 38 /// until Rust 1.83.0. 39 fn vmsd() -> Option<&'static VMStateDescription> { 40 None 41 } 42 } 43 44 /// # Safety 45 /// 46 /// This function is only called through the QOM machinery and 47 /// the `impl_device_class!` macro. 48 /// We expect the FFI user of this function to pass a valid pointer that 49 /// can be downcasted to type `T`. We also expect the device is 50 /// readable/writeable from one thread at any time. 51 unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp: *mut *mut Error) { 52 assert!(!dev.is_null()); 53 let state = dev.cast::<T>(); 54 T::REALIZE.unwrap()(unsafe { &mut *state }); 55 } 56 57 /// # Safety 58 /// 59 /// We expect the FFI user of this function to pass a valid pointer that 60 /// can be downcasted to type `T`. We also expect the device is 61 /// readable/writeable from one thread at any time. 62 unsafe extern "C" fn rust_reset_fn<T: DeviceImpl>(dev: *mut DeviceState) { 63 assert!(!dev.is_null()); 64 let state = dev.cast::<T>(); 65 T::RESET.unwrap()(unsafe { &mut *state }); 66 } 67 68 /// # Safety 69 /// 70 /// We expect the FFI user of this function to pass a valid pointer that 71 /// can be downcasted to type `DeviceClass`, because `T` implements 72 /// `DeviceImpl`. 73 pub unsafe extern "C" fn rust_device_class_init<T: DeviceImpl>( 74 klass: *mut ObjectClass, 75 _: *mut c_void, 76 ) { 77 let mut dc = ::core::ptr::NonNull::new(klass.cast::<DeviceClass>()).unwrap(); 78 unsafe { 79 let dc = dc.as_mut(); 80 if <T as DeviceImpl>::REALIZE.is_some() { 81 dc.realize = Some(rust_realize_fn::<T>); 82 } 83 if <T as DeviceImpl>::RESET.is_some() { 84 bindings::device_class_set_legacy_reset(dc, Some(rust_reset_fn::<T>)); 85 } 86 if let Some(vmsd) = <T as DeviceImpl>::vmsd() { 87 dc.vmsd = vmsd; 88 } 89 bindings::device_class_set_props(dc, <T as DeviceImpl>::properties().as_ptr()); 90 } 91 } 92 93 #[macro_export] 94 macro_rules! impl_device_class { 95 ($type:ty) => { 96 impl $crate::definitions::ClassInitImpl for $type { 97 const CLASS_INIT: Option< 98 unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut ::std::os::raw::c_void), 99 > = Some($crate::device_class::rust_device_class_init::<$type>); 100 const CLASS_BASE_INIT: Option< 101 unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut ::std::os::raw::c_void), 102 > = None; 103 } 104 }; 105 } 106 107 #[macro_export] 108 macro_rules! define_property { 109 ($name:expr, $state:ty, $field:ident, $prop:expr, $type:ty, default = $defval:expr$(,)*) => { 110 $crate::bindings::Property { 111 // use associated function syntax for type checking 112 name: ::std::ffi::CStr::as_ptr($name), 113 info: $prop, 114 offset: $crate::offset_of!($state, $field) as isize, 115 set_default: true, 116 defval: $crate::bindings::Property__bindgen_ty_1 { u: $defval as u64 }, 117 ..$crate::zeroable::Zeroable::ZERO 118 } 119 }; 120 ($name:expr, $state:ty, $field:ident, $prop:expr, $type:ty$(,)*) => { 121 $crate::bindings::Property { 122 // use associated function syntax for type checking 123 name: ::std::ffi::CStr::as_ptr($name), 124 info: $prop, 125 offset: $crate::offset_of!($state, $field) as isize, 126 set_default: false, 127 ..$crate::zeroable::Zeroable::ZERO 128 } 129 }; 130 } 131 132 #[macro_export] 133 macro_rules! declare_properties { 134 ($ident:ident, $($prop:expr),*$(,)*) => { 135 pub static $ident: [$crate::bindings::Property; { 136 let mut len = 1; 137 $({ 138 _ = stringify!($prop); 139 len += 1; 140 })* 141 len 142 }] = [ 143 $($prop),*, 144 $crate::zeroable::Zeroable::ZERO, 145 ]; 146 }; 147 } 148 149 // workaround until we can use --generate-cstr in bindgen. 150 pub const TYPE_DEVICE: &CStr = 151 unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_DEVICE) }; 152 pub const TYPE_SYS_BUS_DEVICE: &CStr = 153 unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_SYS_BUS_DEVICE) }; 154