Re: [PATCH 5/7] rust: io: let I/O locations carry an access mode

[sashiko-bot@kernel.org]

> `Io::read`, `Io::write`, `Io::update` and their fallible variants
> project the view to the given `IoLoc` and access it there. A location
> has no say in which accesses are allowed, so a register cannot be
> declared read-only or write-only.
> 
> Add the `io::access` module with the `Mode` trait and the `ReadWrite`,
> `ReadOnly` and `WriteOnly` modes, and add an `Access` associated type to
> `IoLoc`. Projecting through a location applies its mode: `ReadWrite`
> leaves the view as it is, while `ReadOnly` and `WriteOnly` wrap it in the
> `ReadOnly` and `WriteOnly` views. The bounds of the generic accessors now
> apply to the backend of the restricted view, so a write to a read-only
> location, or a read from a write-only one, does not compile.
> 
> Raw offsets are `ReadWrite`. `OffsetLoc` takes the mode as a type
> parameter that defaults to `ReadWrite`, and `RegisterArray` gets an
> `Access` type, which `register!` sets to `ReadWrite` for now.
> 
> No existing location changes its mode, so there is no functional change.
> A following patch lets `register!` declare read-only and write-only
> registers.
> 
> Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261015-io-access-modes-v1-0-93611b84b5e3@collabora.com?part=5