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()).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 42 impl Deref for DmaObject { 43 type Target = CoherentAllocation<u8>; 44 45 fn deref(&self) -> &Self::Target { 46 &self.dma 47 } 48 } 49 50 impl DerefMut for DmaObject { 51 fn deref_mut(&mut self) -> &mut Self::Target { 52 &mut self.dma 53 } 54 } 55