Re: [PATCH v12 2/3] perf: Add Raspberry Pi BCM2835 AXI PMU driver

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The patch includes out-of-tree `#if LINUX_VERSION_CODE` compatibility macros which violate upstream kernel contribution guidelines.
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--- Patch [2]: [PATCH v12 2/3] perf: Add Raspberry Pi BCM2835 AXI PMU driver ---
commit 26b0420ae938eb90972f1d893f5dc06525dcd8ac
Author: Ian Rogers <[email protected]>

perf: Add Raspberry Pi BCM2835 AXI PMU driver

This commit adds a new performance monitoring driver for the Raspberry Pi
AXI bus (BCM2835/2711), exposing system-level and VideoCore PMU hardware to
the Linux perf subsystem natively via the VideoCore mailbox interface.

> Note on out-of-tree macro compatibility:
> The inclusion of #if LINUX_VERSION_CODE < KERNEL_VERSION(6, 13, 0)
> surrounding hrtimer_setup is intentionally maintained alongside
> this patch to guarantee seamless out-of-tree compilation fallback
> compatibility for Raspberry Pi Long Term Support (LTS) kernel variants.

[Severity: Low]
Is it acceptable to include out-of-tree compatibility notes and macros in a
mainline submission? The Linux kernel typically requires code submitted for
mainline inclusion to be written exclusively against the current kernel API.

> diff --git a/drivers/perf/rpi_axi_pmu.c b/drivers/perf/rpi_axi_pmu.c
> new file mode 100644
> index 0000000000000..eda831d66056f
> --- /dev/null
> +++ b/drivers/perf/rpi_axi_pmu.c
[ ... ]
> +#include <linux/version.h>
> +
> +#if LINUX_VERSION_CODE < KERNEL_VERSION(6, 13, 0)
> +static inline void rpi_hrtimer_setup(struct hrtimer *timer,
> +				     enum hrtimer_restart (*function)(struct hrtimer *),
> +				     clockid_t clock_id, enum hrtimer_mode mode)
> +{
> +	hrtimer_init(timer, clock_id, mode);
> +	timer->function = function;
> +}
> +#define hrtimer_setup rpi_hrtimer_setup
> +#endif

[Severity: Low]
While the commit message notes this is intentional, does this align with
upstream coding style guidelines? Leaving LINUX_VERSION_CODE fallback wrappers
like rpi_hrtimer_setup in the driver may lead to upstream rejection due to
mainline coding policy violations.

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=2