[PATCH 04/10] rust: add bindings for gpio_{in|out} initialization

[Zhao Liu <zhao1.liu@intel.com>]

Wrap qdev_init_gpio_{in|out} as methods in DeviceMethods. And for
qdev_init_gpio_in, based on FnCall, it can support idiomatic Rust
callback without the need for C style wrapper.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
Changes since RFC:
 * Use FnCall to support gpio in callback.
 * Place gpio_{in|out} in DeviceMethods.
 * Accept &[InterruptSource] as the parameter of gpio_out.
---
 rust/qemu-api/src/qdev.rs | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index 32740c873604..96ca8b8aa9ad 100644
--- a/rust/qemu-api/src/qdev.rs
+++ b/rust/qemu-api/src/qdev.rs
@@ -6,16 +6,17 @@
 
 use std::{
     ffi::{CStr, CString},
-    os::raw::c_void,
+    os::raw::{c_int, c_void},
     ptr::NonNull,
 };
 
 pub use bindings::{Clock, ClockEvent, DeviceClass, DeviceState, Property, ResetType};
 
 use crate::{
-    bindings::{self, Error, ResettableClass},
+    bindings::{self, qdev_init_gpio_in, qdev_init_gpio_out, Error, ResettableClass},
     callbacks::FnCall,
     cell::bql_locked,
+    irq::{IRQState, InterruptSource},
     prelude::*,
     qom::{ClassInitImpl, ObjectClass, ObjectImpl, Owned},
     vmstate::VMStateDescription,
@@ -278,6 +279,38 @@ fn do_init_clock_in(
         // IsA<DeviceState> bound.
         do_init_clock_in(unsafe { self.as_mut_ptr() }, name, cb, events)
     }
+
+    fn init_gpio_in<F: for<'a> FnCall<(&'a Self::Target, u32, u32)>>(&self, num_lines: u32, _f: F) {
+        unsafe extern "C" fn rust_irq_handler<T, F: for<'a> FnCall<(&'a T, u32, u32)>>(
+            opaque: *mut c_void,
+            line: c_int,
+            level: c_int,
+        ) {
+            // SAFETY: the opaque was passed as a reference to `T`
+            F::call((unsafe { &*(opaque.cast::<T>()) }, line as u32, level as u32))
+        }
+
+        let gpio_in_cb: unsafe extern "C" fn(*mut c_void, c_int, c_int) =
+            rust_irq_handler::<Self::Target, F>;
+
+        unsafe {
+            qdev_init_gpio_in(
+                self.as_mut_ptr::<DeviceState>(),
+                Some(gpio_in_cb),
+                num_lines as c_int,
+            );
+        }
+    }
+
+    fn init_gpio_out(&self, pins: &[InterruptSource]) {
+        unsafe {
+            qdev_init_gpio_out(
+                self.as_mut_ptr::<DeviceState>(),
+                InterruptSource::as_slice_of_qemu_irq(pins).as_ptr() as *mut *mut IRQState,
+                pins.len() as c_int,
+            );
+        }
+    }
 }
 
 impl<R: ObjectDeref> DeviceMethods for R where R::Target: IsA<DeviceState> {}
-- 
2.34.1