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//! 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
7use kernel::{
8 device::Core,
9 dma::{CoherentAllocation, DataDirection, Device, DmaMask},
10 page, pci,
11 prelude::*,
12 scatterlist::{Owned, SGTable},
13 sync::aref::ARef,
14};
15
16#[pin_data(PinnedDrop)]
17struct DmaSampleDriver {
18 pdev: ARef<pci::Device>,
19 ca: CoherentAllocation<MyStruct>,
20 #[pin]
21 sgt: SGTable<Owned<VVec<u8>>>,
22}
23
24const TEST_VALUES: [(u32, u32); 5] = [
25 (0xa, 0xb),
26 (0xc, 0xd),
27 (0xe, 0xf),
28 (0xab, 0xba),
29 (0xcd, 0xef),
30];
31
32struct MyStruct {
33 h: u32,
34 b: u32,
35}
36
37impl MyStruct {
38 fn new(h: u32, b: u32) -> Self {
39 Self { h, b }
40 }
41}
42// SAFETY: All bit patterns are acceptable values for `MyStruct`.
43unsafe impl kernel::transmute::AsBytes for MyStruct {}
44// SAFETY: Instances of `MyStruct` have no uninitialized portions.
45unsafe impl kernel::transmute::FromBytes for MyStruct {}
46
47kernel::pci_device_table!(
48 PCI_TABLE,
49 MODULE_PCI_TABLE,
50 <DmaSampleDriver as pci::Driver>::IdInfo,
51 [(pci::DeviceId::from_id(pci::Vendor::REDHAT, 0x5), ())]
52);
53
54impl pci::Driver for DmaSampleDriver {
55 type IdInfo = ();
56 const ID_TABLE: pci::IdTable<Self::IdInfo> = &PCI_TABLE;
57
58 fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> impl PinInit<Self, Error> {
59 pin_init::pin_init_scope(move || {
60 dev_info!(pdev.as_ref(), "Probe DMA test driver.\n");
61
62 let mask = DmaMask::new::<64>();
63
64 // SAFETY: There are no concurrent calls to DMA allocation and mapping primitives.
65 unsafe { pdev.dma_set_mask_and_coherent(mask)? };
66
67 let ca: CoherentAllocation<MyStruct> =
68 CoherentAllocation::alloc_coherent(pdev.as_ref(), TEST_VALUES.len(), GFP_KERNEL)?;
69
70 for (i, value) in TEST_VALUES.into_iter().enumerate() {
71 kernel::dma_write!(ca[i] = MyStruct::new(value.0, value.1))?;
72 }
73
74 let size = 4 * page::PAGE_SIZE;
75 let pages = VVec::with_capacity(size, GFP_KERNEL)?;
76
77 let sgt = SGTable::new(pdev.as_ref(), pages, DataDirection::ToDevice, GFP_KERNEL);
78
79 Ok(try_pin_init!(Self {
80 pdev: pdev.into(),
81 ca,
82 sgt <- sgt,
83 }))
84 })
85 }
86}
87
88#[pinned_drop]
89impl PinnedDrop for DmaSampleDriver {
90 fn drop(self: Pin<&mut Self>) {
91 let dev = self.pdev.as_ref();
92
93 dev_info!(dev, "Unload DMA test driver.\n");
94
95 for (i, value) in TEST_VALUES.into_iter().enumerate() {
96 let val0 = kernel::dma_read!(self.ca[i].h);
97 let val1 = kernel::dma_read!(self.ca[i].b);
98 assert!(val0.is_ok());
99 assert!(val1.is_ok());
100
101 if let Ok(val0) = val0 {
102 assert_eq!(val0, value.0);
103 }
104 if let Ok(val1) = val1 {
105 assert_eq!(val1, value.1);
106 }
107 }
108
109 for (i, entry) in self.sgt.iter().enumerate() {
110 dev_info!(dev, "Entry[{}]: DMA address: {:#x}", i, entry.dma_address());
111 }
112 }
113}
114
115kernel::module_pci_driver! {
116 type: DmaSampleDriver,
117 name: "rust_dma",
118 authors: ["Abdiel Janulgue"],
119 description: "Rust DMA test",
120 license: "GPL v2",
121}