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// 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
}
}
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