From 21a85a19b31d96dba38a031d094046f9009e7635 Mon Sep 17 00:00:00 2001
From: Wedson Almeida Filho <wedsonaf@google.com>
Date: Sat, 13 Nov 2021 13:51:12 +0000
Subject: [PATCH] rust: add `PointerWrapper` implementation for `*mut T`.

The implementation is straightforward: converting to `void *` and
borrowing are just pointer casts.

This is used by the GPIO subsystem where some context data is controlled
by the C side, so it is necessarily a raw pointer. (This is hidden from
driver writers though.)

Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
---
 rust/kernel/types.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index e961e68568868b..80aa3037cf1a35 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -128,6 +128,22 @@ impl<T: PointerWrapper + Deref> PointerWrapper for Pin<T> {
     }
 }
 
+impl<T> PointerWrapper for *mut T {
+    type Borrowed<'a> = *mut T;
+
+    fn into_pointer(self) -> *const c_types::c_void {
+        self as _
+    }
+
+    unsafe fn borrow<'a>(ptr: *const c_types::c_void) -> Self::Borrowed<'a> {
+        ptr as _
+    }
+
+    unsafe fn from_pointer(ptr: *const c_types::c_void) -> Self {
+        ptr as _
+    }
+}
+
 /// Runs a cleanup function/closure when dropped.
 ///
 /// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running.