linux-kernel - Re: [PATCH v2] perf: arm_dsu: Support DSU ACPI devices.

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Message-Id: <2684F75B-98BC-4C24-BF29-C5214F9CD3BB@amperemail.onmicrosoft.com>
Date:   Thu, 21 May 2020 08:50:28 -0700
From:   Tuan Phan <tuanphan@...eremail.onmicrosoft.com>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     Tuan Phan <tuanphan@...amperecomputing.com>,
        Mark Rutland <mark.rutland@....com>,
        patches@...erecomputing.com, Will Deacon <will@...nel.org>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2] perf: arm_dsu: Support DSU ACPI devices.



> On May 21, 2020, at 6:55 AM, Sudeep Holla <sudeep.holla@....com> wrote:
> 
> On Mon, May 11, 2020 at 01:32:40PM -0700, Tuan Phan wrote:
>> Add ACPI node probing device support. Each DSU ACPI node
>> defines a "cpus" package with a per cpu MPIDR element.
>> 
>> Signed-off-by: Tuan Phan <tuanphan@...amperecomputing.com>
>> ---
>> Changes in v2:
>> - Removed IRQF_SHARED.
>> - Fixed ACPI runtime detection.
>> 
>> The ACPI binding spec for DSU ACPI node is under beta and located
>> in ARM server group under project "ACPI on ARM".
>> 
>> drivers/perf/arm_dsu_pmu.c | 71 ++++++++++++++++++++++++++++++++++++++++------
>> 1 file changed, 63 insertions(+), 8 deletions(-)
>> 
>> diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
>> index 70968c8..784d177 100644
>> --- a/drivers/perf/arm_dsu_pmu.c
>> +++ b/drivers/perf/arm_dsu_pmu.c
>> @@ -11,6 +11,7 @@
>> #define DRVNAME		PMUNAME "_pmu"
>> #define pr_fmt(fmt)	DRVNAME ": " fmt
>> 
>> +#include <linux/acpi.h>
>> #include <linux/bitmap.h>
>> #include <linux/bitops.h>
>> #include <linux/bug.h>
>> @@ -603,18 +604,21 @@ static struct dsu_pmu *dsu_pmu_alloc(struct platform_device *pdev)
>> }
>> 
>> /**
>> - * dsu_pmu_dt_get_cpus: Get the list of CPUs in the cluster.
>> + * dsu_pmu_dt_get_cpus: Get the list of CPUs in the cluster
>> + * from device tree.
>>  */
>> -static int dsu_pmu_dt_get_cpus(struct device_node *dev, cpumask_t *mask)
>> +static int dsu_pmu_dt_get_cpus(struct platform_device *pdev)
>> {
>> 	int i = 0, n, cpu;
>> 	struct device_node *cpu_node;
>> +	struct dsu_pmu *dsu_pmu =
>> +		(struct dsu_pmu *) platform_get_drvdata(pdev);
>> 
>> -	n = of_count_phandle_with_args(dev, "cpus", NULL);
>> +	n = of_count_phandle_with_args(pdev->dev.of_node, "cpus", NULL);
>> 	if (n <= 0)
>> 		return -ENODEV;
>> 	for (; i < n; i++) {
>> -		cpu_node = of_parse_phandle(dev, "cpus", i);
>> +		cpu_node = of_parse_phandle(pdev->dev.of_node, "cpus", i);
>> 		if (!cpu_node)
>> 			break;
>> 		cpu = of_cpu_node_to_id(cpu_node);
>> @@ -626,11 +630,54 @@ static int dsu_pmu_dt_get_cpus(struct device_node *dev, cpumask_t *mask)
>> 		 */
>> 		if (cpu < 0)
>> 			continue;
>> -		cpumask_set_cpu(cpu, mask);
>> +		cpumask_set_cpu(cpu, &dsu_pmu->associated_cpus);
>> 	}
>> 	return 0;
>> }
>> 
>> +/**
>> + * dsu_pmu_acpi_get_cpus: Get the list of CPUs in the cluster
>> + * from ACPI.
>> + */
>> +static int dsu_pmu_acpi_get_cpus(struct platform_device *pdev)
>> +{
>> +	int i, cpu, ret;
>> +	const union acpi_object *obj;
>> +	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
>> +	struct dsu_pmu *dsu_pmu =
>> +		(struct dsu_pmu *) platform_get_drvdata(pdev);
>> +
>> +	ret = acpi_dev_get_property(adev, "cpus", ACPI_TYPE_PACKAGE, &obj);
> 
> I don't see any property "cpus" in the document:
> DEN 0093 A (Generic ACPI for Arm Components 1.0) [1]
> 
> Is there any newer updates that I need to look at ?
> 
There is a newer DEN 0093 A version but it has not been public yet. Let abandon this
patch and I will post new one when the document has been finalized and available to public.

Thanks,
 
> -- 
> Regards,
> Sudeep
> 
> [1] https://static.docs.arm.com/den0093/a/DEN0093_ACPI_Arm_Components_1.0.pdf