Re: [PATCH RFC 4/5] bus: Add a shared BCMBCA PMC3 PMB transport

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] bus: Missing sparse lock annotations for transport lock functions
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commit f8e671cc4d072dbd3353e224bb3d5cee80468de7
Author: Linus Walleij <linusw@kernel.org>

bus: Add a shared BCMBCA PMC3 PMB transport

This commit adds a bus driver for shared access to the Processor Monitor Bus
(PMB) of the third generation Platform Management Controller (PMC3), initially
for BCM6846. It serializes complete register sequences with a mutex and a
hardware lock.

> diff --git a/include/linux/soc/bcm/bcmbca-pmb.h b/include/linux/soc/bcm/bcmbca-pmb.h
> new file mode 100644
> index 0000000000000..f95523d52e01b
> --- /dev/null
> +++ b/include/linux/soc/bcm/bcmbca-pmb.h
[ ... ]
> +/*
> + * Processor Monitor Bus (PMB) operations sleep. Hold the transport lock
> + * across a complete sequence, including read/modify/write operations.
> + * A successful lock must be paired with unlock, including on errors.
> + */
> +int bcmbca_pmb_lock(struct bcmbca_pmb *pmb);
> +void bcmbca_pmb_unlock(struct bcmbca_pmb *pmb);

[Severity: Low]
Does this code need sparse lock annotations for the transport lock functions?

Without __acquires(&pmb->lock) and __releases(&pmb->lock) on these
prototypes, sparse will report context imbalance warnings when child drivers
call bcmbca_pmb_lock() and bcmbca_pmb_unlock() (when built with C=1). While
sparse has limited strictness with mutexes compared to spinlocks, adding
the annotations can prevent build-time context imbalance warnings.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261014-xg6846b-bcmbca-xrdp-reset-v1-0-daf5d177e113@kernel.org?part=4