Add sample code for allocating and mapping a scatter-gather table
(`SGTable`).
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Co-developed-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
samples/rust/rust_dma.rs | 35 ++++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 9 deletions(-)
diff --git a/samples/rust/rust_dma.rs b/samples/rust/rust_dma.rs
index c5e7cce68654..04007e29fd85 100644
--- a/samples/rust/rust_dma.rs
+++ b/samples/rust/rust_dma.rs
@@ -7,15 +7,19 @@
use kernel::{
bindings,
device::Core,
- dma::{CoherentAllocation, Device, DmaMask},
- pci,
+ dma::{CoherentAllocation, DataDirection, Device, DmaMask},
+ page, pci,
prelude::*,
+ scatterlist::{Owned, SGTable},
types::ARef,
};
+#[pin_data(PinnedDrop)]
struct DmaSampleDriver {
pdev: ARef<pci::Device>,
ca: CoherentAllocation<MyStruct>,
+ #[pin]
+ sgt: SGTable<Owned<VVec<u8>>>,
}
const TEST_VALUES: [(u32, u32); 5] = [
@@ -70,21 +74,30 @@ fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self
kernel::dma_write!(ca[i] = MyStruct::new(value.0, value.1))?;
}
- let drvdata = KBox::new(
- Self {
+ let size = 4 * page::PAGE_SIZE;
+ let pages = VVec::with_capacity(size, GFP_KERNEL)?;
+
+ let sgt = SGTable::new(pdev.as_ref(), pages, DataDirection::ToDevice, GFP_KERNEL);
+
+ let drvdata = KBox::pin_init(
+ try_pin_init!(Self {
pdev: pdev.into(),
ca,
- },
+ sgt <- sgt,
+ }),
GFP_KERNEL,
)?;
- Ok(drvdata.into())
+ Ok(drvdata)
}
}
-impl Drop for DmaSampleDriver {
- fn drop(&mut self) {
- dev_info!(self.pdev.as_ref(), "Unload DMA test driver.\n");
+#[pinned_drop]
+impl PinnedDrop for DmaSampleDriver {
+ fn drop(self: Pin<&mut Self>) {
+ let dev = self.pdev.as_ref();
+
+ dev_info!(dev, "Unload DMA test driver.\n");
for (i, value) in TEST_VALUES.into_iter().enumerate() {
let val0 = kernel::dma_read!(self.ca[i].h);
@@ -99,6 +112,10 @@ fn drop(&mut self) {
assert_eq!(val1, value.1);
}
}
+
+ for (i, entry) in self.sgt.iter().enumerate() {
+ dev_info!(dev, "Entry[{}]: DMA address: {:#x}", i, entry.dma_address());
+ }
}
}
--
2.51.0