Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3//! Simple DMA object wrapper.
4
5use core::ops::{
6 Deref,
7 DerefMut, //
8};
9
10use kernel::{
11 device,
12 dma::CoherentAllocation,
13 page::PAGE_SIZE,
14 prelude::*, //
15};
16
17pub(crate) struct DmaObject {
18 dma: CoherentAllocation<u8>,
19}
20
21impl DmaObject {
22 pub(crate) fn new(dev: &device::Device<device::Bound>, len: usize) -> Result<Self> {
23 let len = core::alloc::Layout::from_size_align(len, PAGE_SIZE)
24 .map_err(|_| EINVAL)?
25 .pad_to_align()
26 .size();
27 let dma = CoherentAllocation::alloc_coherent(dev, len, GFP_KERNEL | __GFP_ZERO)?;
28
29 Ok(Self { dma })
30 }
31
32 pub(crate) fn from_data(dev: &device::Device<device::Bound>, data: &[u8]) -> Result<Self> {
33 Self::new(dev, data.len()).and_then(|mut dma_obj| {
34 // SAFETY: We have just allocated the DMA memory, we are the only users and
35 // we haven't made the device aware of the handle yet.
36 unsafe { dma_obj.write(data, 0)? }
37 Ok(dma_obj)
38 })
39 }
40}
41
42impl Deref for DmaObject {
43 type Target = CoherentAllocation<u8>;
44
45 fn deref(&self) -> &Self::Target {
46 &self.dma
47 }
48}
49
50impl DerefMut for DmaObject {
51 fn deref_mut(&mut self) -> &mut Self::Target {
52 &mut self.dma
53 }
54}