Message-ID: <6795845d-cda8-44dd-85d2-4d51364e0065@de.bosch.com>
Date: Wed, 23 Jul 2025 09:35:45 +0200
From: Dirk Behme <dirk.behme@...bosch.com>
To: Daniel Almeida <daniel.almeida@...labora.com>, Miguel Ojeda
	<ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, Boqun Feng
	<boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, Benno Lossin
	<lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl
	<aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>, Danilo Krummrich
	<dakr@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Rafael
 J. Wysocki" <rafael@...nel.org>
CC: <linux-kernel@...r.kernel.org>, <rust-for-linux@...r.kernel.org>, "Fiona
 Behrens" <me@...enk.dev>
Subject: Re: [PATCH v15 0/3] rust: platform: add Io support

On 17/07/2025 17:55, Daniel Almeida wrote:
> Changes in v15:
> - Use a default string in ioremap() if the resource doesn't have a name
> - Fix the doctests in mem.rs to use the new name for io_request_by_*
> - Link to v14: https://lore.kernel.org/r/20250716-topics-tyr-platform_iomem-v14-0-2c2709135cb2@collabora.com


I'm not sure if it is too late for this (already applied?) but with

https://lore.kernel.org/rust-for-linux/dd34e5f4-5027-4096-9f32-129c8a067d0a@de.bosch.com/

in case it helps:

Tested-by: Dirk Behme <dirk.behme@...bosch.com>

Thanks!

Dirk


> Changes in v14:
> - Changed Resource::size() to return ResourceSize instead of u64 (Alice)
> - Changed Resource::name() to return a non-static lifetime (i.e.: the
>   lifetime of &self). It turns out that although this value tends to often
>   point to string literals, this value is not necessarily static  in C.
>   (Thanks for bringing this up, Alice)
> - "name" is now owned by the Region. We were storing Resource::name()
>   previously as that was 'static, but that is not the case anymore. The
>   string is now copied from Resource::name() instead. If there is no name,
>   we fail.
> - Changed Resource::name() to return an Option, as the name may be NULL in
>   C (see the DEFINE_RES_* family of macros in C)
> - Added a TODO to the "size" cast in IoMem::ioremap(), noting that we
>   should fix this in C in the future (Thanks, Alice)
> - Casting "size" in IoMem::ioremap() only once now (thanks, Alice)
> - Introduced Flags::new(), which derives from a comment in the request_irq
>   series. This introduces a build_assert to reduce the number of casts.
> - Added Alice's r-b to patches 1-2
> - Added Miguel's a-b to patches 1-3 (Given in v11 and forgotten)
> - Link to v13: https://lore.kernel.org/r/20250711-topics-tyr-platform_iomem-v13-0-06328b514db3@collabora.com
> 
> Changes in v13:
> - Change ResourceSize to just be bindings::phys_addr_t (Danilo)
> - Mention that ResourceSize can be 32bits even on 64bit architectures (Alice)
> - Use the deref impl for Resource to avoid unsafe (Alice)
> - Change Resource::as_ref() to Resource::from_raw() (Alice)
> - Mention that it's ok for __request_region to store the name as we require
>   it to be 'static
> - Remove all instances of core::ffi::* as these are in the prelude already
>   (Alice)
> - Resource::start() and Resoruce::flags() do not copy &self anymore (Alice)
> - Define the resource::Flags constants within impl Flags itself (Alice)
> - Apply the diff from Danilo to return impl PinInit<...> instead of
>   Result<impl PinInin<...>> from the iomap() functions.
> - Fix the docs in patch 2 (Alice)
> - Use try_into() instead of blindly casting ResourceSize to usize (Alice)
> - Rename request_io_by{index,name} to io_request_by{index,name} (Danilo)
> - Link to v12: https://lore.kernel.org/rust-for-linux/20250704-topics-tyr-platform_iomem-v12-0-1d3d4bd8207d@collabora.com/
> 
> Changes in v12:
> - Fixed the typos that Miguel pointed out in resource.rs
> - Fixed a typo where thread was written as thead
> - Removed ioport_resource() and iomem_resource() (Danilo)
> - Created IoRequest<'a> and gave it an unsafe constructor (Danilo)
> - Moved all the logic to map resources from platform.rs to IoRequest.
> - Dropped the last patch as a result of the above.
> - Link to v11: https://lore.kernel.org/r/20250701-topics-tyr-platform_iomem-v11-0-6cd5d5061151@collabora.com
> 
> Changes in v11:
> - Rebased on top of driver-core-next (to get the latest Devres changes)
> - Changed the order between requesting the resource and mapping it
>   (Danilo)
> - Link to v10: https://lore.kernel.org/r/20250623-topics-tyr-platform_iomem-v10-0-ed860a562940@collabora.com
> 
> Changes in v10:
> - Rebased on driver-core-next
> - Fixed examples (they were still using try_access())
> - Removed map_err() from the examples, as it was not needed.
> - Added a pub use for Resource in io.rs
> - Reworked the platform code to make use of the pub use above
> - Link to v9: https://lore.kernel.org/r/20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com
> 
> Changes in v9:
> - Rebased on top of nova-next (for Devres::access())
> - Reworked the documentation to add more markdown.
> - Converted to &raw mut instead of addr_of_mut!()
> - Renamed 'from_ptr' to 'as_ref' for consistency
> - Changed the IoMem examples to use the signature for probe()
> - Changed resource() to resource_by_index(). It's a better fit given
>   the existance of resource_by_name().
> - Created a separate patch for the resource accessors above.
> - Moved the accessors into the generic impl block, so they work with all
>   Device contexts.
> - Take Device<Bound> where applicable
> - Renamed "ioremap_*" to "iomap_*", in order to be consistent with the code
>   in pci.rs
> - Switched to Devres::access()
> - Link to v8: https://lore.kernel.org/r/20250509-topics-tyr-platform_iomem-v8-0-e9f1725a40da@collabora.com
> 
> rust: platform: add Io support
> 
> Changes in v8:
> - Rebased on driver-core-next
> - Opted to wait for 'rust/revocable: add try_with() convenience method' to
>   land instead of using the suggested closure (let me know if we should
>   just switch to the closure anyways)
> - Cc'd more people
> - Link to v7: https://lore.kernel.org/r/20250318-topics-tyr-platform_iomem-v7-0-7438691d9ef7@collabora.com
> 
> Changes in v7:
> 
> - Rebased on top of rust-next
> - Fixed a few Clippy lints
> - Fixed typos (Thanks Daniel!)
> - "struct Flags" now contains a usize (thanks Daniel)
> - Fixed "Doc list without indentation" warning (thanks, Guangbo)
> 
> Thanks, Fiona {
> - Removed RequestFn, as all functions simply used request_region and RequestFn
>   had issues. Only request_region() is exposed now.
> - Gated iomem_resource on CONFIG_HAS_IOMEM
> - Require that the name argument be 'static
> }
> 
> - Correctly check for IORESOURCE_MEM_NONPOSTED. We now call ioremap_np if that
>   is set (thanks, Lina!)
> - Remove #[dead_code] attribute from ExclusiveIoMem::region.
> 
> Changes in v6:
> 
> - Added Fiona as co-developer in the first patch, as I merged part of her code
> from the LED driver series (thanks, Fiona)
> 
> - (Fiona) added the ResourceSize type, thereby fixing the u32 vs u64 issues
>   pointed out by Christian
> 
> - Moved the request_region, release_region and friends to resource.rs
> 
> - Added the Region type. This type represents a resource returned by
>   `request_region` and friends. It is also owned, representing the fact
>   that the region remains marked as busy until release_region is called on
>   drop. (Thanks Alice, for pointing out this pattern)
> 
> - Rewrote the IoMem abstraction to implement a separate type for exclusive
>   access to an underlying region. I really disliked the `EXCLUSIVE` const
>   generic, as it was definitely not ergonomic, i.e.:
> 
>   `IoMem<0, false>`
> 
>   ...doesn't really say much. In fact, I believe that boolean parameters
>   hurt readability in general.
> 
>   This new approach lets users build either regular IoMem's, which basically
>   call ioremap under the covers, and ExclusiveIoMem's , which also call request_region
>   via the Region type.
> 
> - Added access to the ioresource_port and ioresource_mem globals.
> 
> Link to v5: https://lore.kernel.org/rust-for-linux/20250116125632.65017-1-daniel.almeida@collabora.com/
> 
> 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: add resource accessors
> 
>  rust/bindings/bindings_helper.h |   1 +
>  rust/helpers/io.c               |  41 ++++++
>  rust/kernel/io.rs               |   5 +
>  rust/kernel/io/mem.rs           | 283 ++++++++++++++++++++++++++++++++++++++++
>  rust/kernel/io/resource.rs      | 229 ++++++++++++++++++++++++++++++++
>  rust/kernel/platform.rs         |  60 ++++++++-
>  6 files changed, 618 insertions(+), 1 deletion(-)
> ---
> base-commit: f5d3ef25d238901a76fe0277787afa44f7714739
> change-id: 20250318-topics-tyr-platform_iomem-1710a177e1df
> 
> Best regards,

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