Commit 5444799d authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

samples: rust: dma: add sample code for SGTable 



Add sample code for allocating and mapping a scatter-gather table
(`SGTable`).

Reviewed-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Reviewed-by: default avatarDaniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Co-developed-by: default avatarAbdiel Janulgue <abdiel.janulgue@gmail.com>
Signed-off-by: default avatarAbdiel Janulgue <abdiel.janulgue@gmail.com>
Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250828133323.53311-5-dakr@kernel.org


Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 05aa6fb1

samples/rust/rust_dma.rs

+26 −9
Original line number Diff line number Diff line
@@ -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());

        }

    }

}