xref: /linux/samples/rust/rust_dma.rs (revision 1b8ac37677d307cd0fc10f6bf9bceae2c282bdb4)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 //! Rust DMA api test (based on QEMU's `pci-testdev`).
4 //!
5 //! To make this driver probe, QEMU must be run with `-device pci-testdev`.
6 
7 use kernel::{
8     device::Core,
9     dma::{CoherentAllocation, Device, DmaMask},
10     pci,
11     prelude::*,
12     types::ARef,
13 };
14 
15 struct DmaSampleDriver {
16     pdev: ARef<pci::Device>,
17     ca: CoherentAllocation<MyStruct>,
18 }
19 
20 const TEST_VALUES: [(u32, u32); 5] = [
21     (0xa, 0xb),
22     (0xc, 0xd),
23     (0xe, 0xf),
24     (0xab, 0xba),
25     (0xcd, 0xef),
26 ];
27 
28 struct MyStruct {
29     h: u32,
30     b: u32,
31 }
32 
33 impl MyStruct {
34     fn new(h: u32, b: u32) -> Self {
35         Self { h, b }
36     }
37 }
38 // SAFETY: All bit patterns are acceptable values for `MyStruct`.
39 unsafe impl kernel::transmute::AsBytes for MyStruct {}
40 // SAFETY: Instances of `MyStruct` have no uninitialized portions.
41 unsafe impl kernel::transmute::FromBytes for MyStruct {}
42 
43 kernel::pci_device_table!(
44     PCI_TABLE,
45     MODULE_PCI_TABLE,
46     <DmaSampleDriver as pci::Driver>::IdInfo,
47     [(pci::DeviceId::from_id(pci::Vendor::REDHAT, 0x5), ())]
48 );
49 
50 impl pci::Driver for DmaSampleDriver {
51     type IdInfo = ();
52     const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
53 
54     fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self>>> {
55         dev_info!(pdev.as_ref(), "Probe DMA test driver.\n");
56 
57         let mask = DmaMask::new::<64>();
58 
59         // SAFETY: There are no concurrent calls to DMA allocation and mapping primitives.
60         unsafe { pdev.dma_set_mask_and_coherent(mask)? };
61 
62         let ca: CoherentAllocation<MyStruct> =
63             CoherentAllocation::alloc_coherent(pdev.as_ref(), TEST_VALUES.len(), GFP_KERNEL)?;
64 
65         for (i, value) in TEST_VALUES.into_iter().enumerate() {
66             kernel::dma_write!(ca[i] = MyStruct::new(value.0, value.1))?;
67         }
68 
69         let drvdata = KBox::new(
70             Self {
71                 pdev: pdev.into(),
72                 ca,
73             },
74             GFP_KERNEL,
75         )?;
76 
77         Ok(drvdata.into())
78     }
79 }
80 
81 impl Drop for DmaSampleDriver {
82     fn drop(&mut self) {
83         dev_info!(self.pdev.as_ref(), "Unload DMA test driver.\n");
84 
85         for (i, value) in TEST_VALUES.into_iter().enumerate() {
86             let val0 = kernel::dma_read!(self.ca[i].h);
87             let val1 = kernel::dma_read!(self.ca[i].b);
88             assert!(val0.is_ok());
89             assert!(val1.is_ok());
90 
91             if let Ok(val0) = val0 {
92                 assert_eq!(val0, value.0);
93             }
94             if let Ok(val1) = val1 {
95                 assert_eq!(val1, value.1);
96             }
97         }
98     }
99 }
100 
101 kernel::module_pci_driver! {
102     type: DmaSampleDriver,
103     name: "rust_dma",
104     authors: ["Abdiel Janulgue"],
105     description: "Rust DMA test",
106     license: "GPL v2",
107 }
108