[PATCH 3/3] perf/arm_cspmu: nvidia: fix BDF calculation examples in PCIE PMU docs

[Besar Wicaksono]

> -----Original Message-----
> From: Saurav Sachidanand <sauravsc at amazon.com>
> Sent: Monday, May 11, 2026 4:09 PM
> To: Will Deacon <will at kernel.org>
> Cc: Mark Rutland <mark.rutland at arm.com>; Besar Wicaksono
> <bwicaksono at nvidia.com>; Ilkka Koskinen
> <ilkka at os.amperecomputing.com>; Jon Hunter <jonathanh at nvidia.com>;
> linux-arm-kernel at lists.infradead.org; linux-perf-users at vger.kernel.org; linux-
> kernel at vger.kernel.org; aghayev at amazon.com; juew at amazon.com; Saurav
> Sachidanand <sauravsc at amazon.com>
> Subject: [PATCH 3/3] perf/arm_cspmu: nvidia: fix BDF calculation examples in
> PCIE PMU docs
> 
> External email: Use caution opening links or attachments
> 
> 
> The BDF hex values in the documentation examples are inconsistent with
> the stated formula (bus << 8) + (device << 3) + (function):
> 
>   - BDF 27:01.1: documented as 0x2781, correct value is 0x2709
>     (0x27 << 8) + (0x01 << 3) + 0x1 = 0x2709
>   - BDF 01:01.0: documented as 0x0180, correct value is 0x0108
>     (0x01 << 8) + (0x01 << 3) + 0x0 = 0x0108
> 
> It appears (device << 7) was used instead of (device << 3) when
> computing the example values.
> 
> Fixes: bf585ba14726 ("perf/arm_cspmu: nvidia: Add Tegra410 PCIE PMU")
> Signed-off-by: Saurav Sachidanand <sauravsc at amazon.com>

Thanks for the fix.
Reviewed-by: Besar Wicaksono <bwicaksono at nvidia.com>

> ---
>  Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
> b/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
> index 0656223b61d47..24f0e801d7b80 100644
> --- a/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
> +++ b/Documentation/admin-guide/perf/nvidia-tegra410-pmu.rst
> @@ -170,7 +170,7 @@ The list of event filters:
>      devices in root port 0 to 3.
>    * src_bdf: the BDF that will be monitored. This is a 16-bit value that
>      follows formula: (bus << 8) + (device << 3) + (function). For example, the
> -    value of BDF 27:01.1 is 0x2781.
> +    value of BDF 27:01.1 is 0x2709.
>    * src_bdf_en: enable the BDF filter. If this is set, the BDF filter value in
>      "src_bdf" is used to filter the traffic.
> 
> @@ -215,7 +215,7 @@ Example usage:
>  * Count event id 0x4 from BDF 01:01.0 of PCIE RC-4 on socket 0 targeting all
>    destinations::
> 
> -    perf stat -a -e
> nvidia_pcie_pmu_0_rc_4/event=0x4,src_bdf=0x0180,src_bdf_en=0x1/
> +    perf stat -a -e
> nvidia_pcie_pmu_0_rc_4/event=0x4,src_bdf=0x0108,src_bdf_en=0x1/
> 
>  .. _NVIDIA_T410_PCIE_PMU_RC_Mapping_Section:
> 
> --
> 2.47.3