mirror of https://github.com/torvalds/linux.git
55 lines
1.3 KiB
Rust
55 lines
1.3 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Simple DMA object wrapper.
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use core::ops::{
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Deref,
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DerefMut, //
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};
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use kernel::{
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device,
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dma::CoherentAllocation,
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page::PAGE_SIZE,
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prelude::*, //
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};
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pub(crate) struct DmaObject {
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dma: CoherentAllocation<u8>,
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}
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impl DmaObject {
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pub(crate) fn new(dev: &device::Device<device::Bound>, len: usize) -> Result<Self> {
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let len = core::alloc::Layout::from_size_align(len, PAGE_SIZE)
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.map_err(|_| EINVAL)?
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.pad_to_align()
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.size();
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let dma = CoherentAllocation::alloc_coherent(dev, len, GFP_KERNEL | __GFP_ZERO)?;
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Ok(Self { dma })
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}
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pub(crate) fn from_data(dev: &device::Device<device::Bound>, data: &[u8]) -> Result<Self> {
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Self::new(dev, data.len()).and_then(|mut dma_obj| {
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// SAFETY: We have just allocated the DMA memory, we are the only users and
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// we haven't made the device aware of the handle yet.
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unsafe { dma_obj.write(data, 0)? }
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Ok(dma_obj)
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})
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}
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}
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impl Deref for DmaObject {
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type Target = CoherentAllocation<u8>;
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fn deref(&self) -> &Self::Target {
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&self.dma
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}
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}
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impl DerefMut for DmaObject {
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fn deref_mut(&mut self) -> &mut Self::Target {
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&mut self.dma
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}
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}
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