1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Simple DMA object wrapper. 4 5 use core::ops::{ 6 Deref, 7 DerefMut, // 8 }; 9 10 use kernel::{ 11 device, 12 dma::CoherentAllocation, 13 page::PAGE_SIZE, 14 prelude::*, // 15 }; 16 17 pub(crate) struct DmaObject { 18 dma: CoherentAllocation<u8>, 19 } 20 21 impl 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()).map(|mut dma_obj| { 34 // TODO[COHA]: replace with `CoherentAllocation::write()` once available. 35 // SAFETY: 36 // - `dma_obj`'s size is at least `data.len()`. 37 // - We have just created this object and there is no other user at this stage. 38 unsafe { 39 core::ptr::copy_nonoverlapping( 40 data.as_ptr(), 41 dma_obj.dma.start_ptr_mut(), 42 data.len(), 43 ); 44 } 45 46 dma_obj 47 }) 48 } 49 } 50 51 impl Deref for DmaObject { 52 type Target = CoherentAllocation<u8>; 53 54 fn deref(&self) -> &Self::Target { 55 &self.dma 56 } 57 } 58 59 impl DerefMut for DmaObject { 60 fn deref_mut(&mut self) -> &mut Self::Target { 61 &mut self.dma 62 } 63 } 64