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// SPDX-License-Identifier: GPL-2.0
//! Simple DMA object wrapper.
use core::ops::{Deref, DerefMut};
use kernel::device;
use kernel::dma::CoherentAllocation;
use kernel::page::PAGE_SIZE;
use kernel::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()).map(|mut dma_obj| {
// TODO[COHA]: replace with `CoherentAllocation::write()` once available.
// SAFETY:
// - `dma_obj`'s size is at least `data.len()`.
// - We have just created this object and there is no other user at this stage.
unsafe {
core::ptr::copy_nonoverlapping(
data.as_ptr(),
dma_obj.dma.start_ptr_mut(),
data.len(),
);
}
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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