Re: [PATCH RESEND v5 0/3] rust: platform: add Io support

Christian Schrefl
2025-01-16T21:24:53Z

Hi Daniel

On 16.01.25 1:56 PM, Daniel Almeida wrote:
> Changes in v5:
>
> - resend v5, as the r4l list was not cc'd
> - use srctree where applicable in the docs (Alice)
> - Remove 'mut' in Resource::from_ptr() (Alice)
> - Add 'invariants' section for Resource (Alice)
> - Fix typos in mem.rs (Alice)
> - Turn 'exclusive' into a const generic (Alice)
> - Fix example in platform.rs (Alice)
> - Rework the resource.is_null() check (Alice)
> - Refactor IoMem::new() to return DevRes<IoMem> directly (Danilo)
>
> link to v4: https://lore.kernel.org/rust-for-linux/20250109133057.243751-1-daniel.almeida@collabora.com/
>
> Changes in v4:
>
> - Rebased on top of driver-core-next
> - Split series in multiple patches (Danilo)
> - Move IoMem and Resource into its own files (Danilo)
> - Fix a missing "if exclusive {...}" check (Danilo)
> - Fixed the example, since it was using the old API (Danilo)
> - Use Opaque in `Resource`, instead of NonNull and PhantomData (Boqun)
> - Highlight that non-exclusive access to the iomem might be required in some cases
> - Fixed the safety comment in IoMem::deref()
>
> Link to v3: https://lore.kernel.org/rust-for-linux/20241211-topic-panthor-rs-platform_io_support-v3-1-08ba707e5e3b@collabora.com/
>
> Changes in v3:
> - Rebased on top of v5 for the PCI/Platform abstractions
> - platform_get_resource is now called only once when calling ioremap
> - Introduced a platform::Resource type, which is bound to the lifetime of the
> platform Device
> - Allow retrieving resources from the platform device either by index or
> name
> - Make request_mem_region() optional
> - Use resource.name() in request_mem_region
> - Reword the example to remove an unaligned, out-of-bounds offset
> - Update the safety requirements of platform::IoMem
>
> Changes in v2:
> - reworked the commit message
> - added missing request_mem_region call (Thanks Alice, Danilo)
> - IoMem::new() now takes the platform::Device, the resource number and
> the name, instead of an address and a size (thanks, Danilo)
> - Added a new example for both sized and unsized versions of IoMem.
> - Compiled the examples using kunit.py (thanks for the tip, Alice!)
> - Removed instances of `foo as _`. All `as` casts now spell out the actual
> type.
> - Now compiling with CLIPPY=1 (I realized I had forgotten, sorry)
> - Rebased on top of rust-next to check for any warnings given the new
> unsafe lints.
>
> Daniel Almeida (3):
> rust: io: add resource abstraction
> rust: io: mem: add a generic iomem abstraction
> rust: platform: allow ioremap of platform resources
>
> rust/bindings/bindings_helper.h | 1 +
> rust/helpers/io.c | 17 ++++++
> rust/kernel/io.rs | 3 +
> rust/kernel/io/mem.rs | 98 +++++++++++++++++++++++++++++
> rust/kernel/io/resource.rs | 53 ++++++++++++++++
> rust/kernel/platform.rs | 105 +++++++++++++++++++++++++++++++-
> 6 files changed, 276 insertions(+), 1 deletion(-)
> create mode 100644 rust/kernel/io/mem.rs
> create mode 100644 rust/kernel/io/resource.rs
>

I've tested this patch-set with my ARM 32-bit arm patches[0] on a De1Soc (Fpga + Arm Cortex A9).

I've got it to work by changing the three instances of u64 (mentioned on the individual patches) to bindings::resource_size_t.
I used a small Fpga configuration that allows me to change a led from the kernel driver.

So with these fixed:

Tested-by: Christian Schrefl <chrisi.schrefl@gmail.com>

[0]: https://github.com/onestacked/linux/commit/f84be45f7311ea5b5a76123028f9fb8fda9f9e7f

Cheers
Christian