From a2938fc7a3370f87069a8bbdf2179949d98b8241 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Sun, 19 Jan 2020 12:36:02 +1100
Subject: [PATCH 1/2] Allow Dma to use ?Sized types, mostly for slices.

---
 src/io/dma.rs | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/io/dma.rs b/src/io/dma.rs
index f2a9a12..44ca782 100644
--- a/src/io/dma.rs
+++ b/src/io/dma.rs
@@ -24,7 +24,7 @@ impl Drop for PhysBox {
     }
 }
 
-pub struct Dma<T> {
+pub struct Dma<T: ?Sized> {
     phys: PhysBox,
     virt: *mut T
 }
@@ -49,28 +49,45 @@ impl<T> Dma<T> {
             virt: virt
         })
     }
-
     pub fn physical(&self) -> usize {
         self.phys.address
     }
 }
+impl<T> Dma<[T]> {
+    /// Crates a new DMA buffer with a size only known at runtime.
+    /// ## Safety
+    /// * `T` must be properly aligned.
+    /// * `T` must be valid as zeroed (i.e. no NonNull pointers).
+    pub unsafe fn zeroed_unsized(count: usize) -> Result<Self> {
+        let phys = PhysBox::new(mem::size_of::<T>() * count)?;
+        let virt_ptr = crate::physmap(phys.address, phys.size, crate::PHYSMAP_WRITE)? as *mut T;
+        ptr::write_bytes(virt_ptr, 0, count);
 
-impl<T> Deref for Dma<T> {
+        let virt = core::slice::from_raw_parts_mut(virt_ptr, count);
+
+        Ok(Dma {
+            phys,
+            virt,
+        })
+    }
+}
+
+impl<T: ?Sized> Deref for Dma<T> {
     type Target = T;
     fn deref(&self) -> &T {
         unsafe { &*self.virt }
     }
 }
 
-impl<T> DerefMut for Dma<T> {
+impl<T: ?Sized> DerefMut for Dma<T> {
     fn deref_mut(&mut self) -> &mut T {
         unsafe { &mut *self.virt }
     }
 }
 
-impl<T> Drop for Dma<T> {
+impl<T: ?Sized> Drop for Dma<T> {
     fn drop(&mut self) {
-        unsafe { drop(ptr::read(self.virt)); }
-        let _ = unsafe { crate::physunmap(self.virt as usize) };
+        unsafe { ptr::drop_in_place(self.virt) }
+        let _ = unsafe { crate::physunmap(self.virt as *mut u8 as usize) };
     }
 }

From 08a3800e873b2cf018ecd7fb2695b0ea43326a9b Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Sun, 19 Jan 2020 13:16:56 +1100
Subject: [PATCH 2/2] Also allow ?Sized types to get the physaddr.

---
 src/io/dma.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/io/dma.rs b/src/io/dma.rs
index 44ca782..d3ffbb9 100644
--- a/src/io/dma.rs
+++ b/src/io/dma.rs
@@ -49,10 +49,13 @@ impl<T> Dma<T> {
             virt: virt
         })
     }
+}
+impl<T: ?Sized> Dma<T> {
     pub fn physical(&self) -> usize {
         self.phys.address
     }
 }
+
 impl<T> Dma<[T]> {
     /// Crates a new DMA buffer with a size only known at runtime.
     /// ## Safety