diff options
| author | Beata Michalska <beata.michalska@arm.com> | 2026-01-28 14:53:20 +0100 |
|---|---|---|
| committer | Danilo Krummrich <dakr@kernel.org> | 2026-01-28 16:53:24 +0100 |
| commit | c71257394bc9c59ea727803f6e55e83fe63db74e (patch) | |
| tree | 09dd812ecb0d3b5cb812a13cea19e78920a1f45f /rust | |
| parent | 7c60d964fbb100103730db9560f5594c1c4fc844 (diff) | |
rust: dma: allow drivers to tune max segment size
Make dma_set_max_seg_size() available to Rust so drivers can perform
standard DMA setup steps.
Signed-off-by: Beata Michalska <beata.michalska@arm.com>
Acked-by: Robin Murphy <robvin.murphy@arm.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260128135320.689046-1-beata.michalska@arm.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Diffstat (limited to 'rust')
| -rw-r--r-- | rust/helpers/dma.c | 6 | ||||
| -rw-r--r-- | rust/kernel/dma.rs | 17 |
2 files changed, 23 insertions, 0 deletions
diff --git a/rust/helpers/dma.c b/rust/helpers/dma.c index e7defeecda71..20232ac64850 100644 --- a/rust/helpers/dma.c +++ b/rust/helpers/dma.c @@ -43,3 +43,9 @@ size_t rust_helper_dma_max_mapping_size(struct device *dev) { return dma_max_mapping_size(dev); } + +__rust_helper void rust_helper_dma_set_max_seg_size(struct device *dev, + unsigned int size) +{ + dma_set_max_seg_size(dev, size); +} diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs index acc65b1e0f24..909d56fd5118 100644 --- a/rust/kernel/dma.rs +++ b/rust/kernel/dma.rs @@ -85,6 +85,23 @@ pub trait Device: AsRef<device::Device<Core>> { bindings::dma_set_mask_and_coherent(self.as_ref().as_raw(), mask.value()) }) } + + /// Set the maximum size of a single DMA segment the device may request. + /// + /// This method is usually called once from `probe()` as soon as the device capabilities are + /// known. + /// + /// # Safety + /// + /// This method must not be called concurrently with any DMA allocation or mapping primitives, + /// such as [`CoherentAllocation::alloc_attrs`]. + unsafe fn dma_set_max_seg_size(&self, size: u32) { + // SAFETY: + // - By the type invariant of `device::Device`, `self.as_ref().as_raw()` is valid. + // - The safety requirement of this function guarantees that there are no concurrent calls + // to DMA allocation and mapping primitives using this parameter. + unsafe { bindings::dma_set_max_seg_size(self.as_ref().as_raw(), size) } + } } /// A DMA mask that holds a bitmask with the lowest `n` bits set. |