1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/gpu/nova-core/dma.rs b/drivers/gpu/nova-core/dma.rs
new file mode 100644
index 000000000000..7215398969da
--- /dev/null
+++ b/drivers/gpu/nova-core/dma.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Simple DMA object wrapper.
+
+use core::ops::{
+    Deref,
+    DerefMut, //
+};
+
+use kernel::{
+    device,
+    dma::CoherentAllocation,
+    page::PAGE_SIZE,
+    prelude::*, //
+};
+
+pub(crate) struct DmaObject {
+    dma: CoherentAllocation<u8>,
+}
+
+impl DmaObject {
+    pub(crate) fn new(dev: &device::Device<device::Bound>, len: usize) -> Result<Self> {
+        let len = core::alloc::Layout::from_size_align(len, PAGE_SIZE)
+            .map_err(|_| EINVAL)?
+            .pad_to_align()
+            .size();
+        let dma = CoherentAllocation::alloc_coherent(dev, len, GFP_KERNEL | __GFP_ZERO)?;
+
+        Ok(Self { dma })
+    }
+
+    pub(crate) fn from_data(dev: &device::Device<device::Bound>, data: &[u8]) -> Result<Self> {
+        Self::new(dev, data.len()).and_then(|mut dma_obj| {
+            // SAFETY: We have just allocated the DMA memory, we are the only users and
+            // we haven't made the device aware of the handle yet.
+            unsafe { dma_obj.write(data, 0)? }
+            Ok(dma_obj)
+        })
+    }
+}
+
+impl Deref for DmaObject {
+    type Target = CoherentAllocation<u8>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.dma
+    }
+}
+
+impl DerefMut for DmaObject {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.dma
+    }
+}