Re: [PATCH v3 1/5] perf/arm_cspmu: Add arm_cspmu_acpi_dev_get

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 30/09/2025 14:00, Besar Wicaksono wrote:
> 
> 
>> -----Original Message-----
>> From: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Sent: Tuesday, September 30, 2025 3:38 AM
>> To: Besar Wicaksono <bwicaksono@nvidia.com>; will@kernel.org;
>> robin.murphy@arm.com; ilkka@os.amperecomputing.com
>> Cc: linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; linux-
>> tegra@vger.kernel.org; mark.rutland@arm.com; Thierry Reding
>> <treding@nvidia.com>; Jon Hunter <jonathanh@nvidia.com>; Vikram Sethi
>> <vsethi@nvidia.com>; Rich Wiley <rwiley@nvidia.com>; Shanker Donthineni
>> <sdonthineni@nvidia.com>
>> Subject: Re: [PATCH v3 1/5] perf/arm_cspmu: Add arm_cspmu_acpi_dev_get
>>
>> External email: Use caution opening links or attachments
>>
>>
>> On 30/09/2025 01:26, Besar Wicaksono wrote:
>> > Add interface to get ACPI device associated with the
>> > PMU. This ACPI device may contain additional properties
>> > not covered by the standard properties.
>> >
>> > Signed-off-by: Besar Wicaksono <bwicaksono@nvidia.com>
>>
>> Repeat: Where is the user ?
> 
> I thought you were okay if the use case is on future (different) series.
> 
> So, this is a heads up on what I will have in nvidia_cspmu when adding the
> new PMU support. Do you prefer it to be part of this series?

No, I recommended the opposite. Apologies, if that wasn't clear.
Add a helper only when there is a user.

Suzuki


> 
> +static u32 nv_cspmu_get_inst_id(const struct arm_cspmu *cspmu)
> 
> +{
> 
> +     u32 inst_id;
> 
> +     struct fwnode_handle *fwnode;
> 
> +     struct acpi_device *adev;
> 
> +
> 
> +     inst_id = 0;
> 
> +
> 
> +     adev = arm_cspmu_acpi_dev_get(cspmu);
> 
> +     if (!adev)
> 
> +           return 0;
> 
> +
> 
> +     fwnode = acpi_fwnode_handle(adev);
> 
> +     if (fwnode && fwnode_property_read_u32(fwnode, "instance_id", 
> &inst_id))
> 
> +           kstrtou32(acpi_device_uid(adev), 0, &inst_id);
> 
> +
> 
> +     acpi_dev_put(adev);
> 
> +     return inst_id;
> 
> +}
> 
> Thanks,
> Besar
> 
>