[PATCH v2 0/5] dma::Device trait and DMA mask

From: Danilo Krummrich
Date: Wed Jul 16 2025 - 11:09:42 EST


This patch series adds the dma::Device trait to be implemented by bus devices on
DMA capable busses.

The dma::Device trait implements methods to set the DMA mask for for such
devices.

The first two bus devices implementing the trait are PCI and platform.

Unfortunately, the DMA mask setters have to be unsafe for now, since, with
reasonable effort, we can't prevent drivers from data races writing and reading
the DMA mask fields concurrently (see also [1]).

Link: https://lore.kernel.org/lkml/DB6YTN5P23X3.2S0NH4YECP1CP@xxxxxxxxxx/ [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/dakr/linux.git/log/?h=rust/dma-mask

Changes in v2:
- replace dma_bit_mask() with a new type DmaMask
- mention that DmaMask is the Rust equivalent of the C macro DMA_BIT_MASK()
- make DmaMask::new() fallible
- inline DmaMask methods

Danilo Krummrich (5):
rust: dma: implement `dma::Device` trait
rust: dma: add DMA addressing capabilities
rust: pci: implement the `dma::Device` trait
rust: platform: implement the `dma::Device` trait
rust: samples: dma: set DMA mask

rust/helpers/dma.c | 5 ++
rust/kernel/dma.rs | 125 ++++++++++++++++++++++++++++++++++++---
rust/kernel/pci.rs | 2 +
rust/kernel/platform.rs | 2 +
samples/rust/rust_dma.rs | 14 ++++-
5 files changed, 140 insertions(+), 8 deletions(-)


base-commit: d49ac7744f578bcc8708a845cce24d3b91f86260
--
2.50.0