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SubjectRe: [PATCH v3] perf: arm_dsu: Support DSU ACPI devices
[+ Suzuki as I'd like his Ack on this]

On Fri, Aug 14, 2020 at 05:39:40PM -0700, Tuan Phan wrote:
> Add support for probing device from ACPI node.
> Each DSU ACPI node and its associated cpus are inside a cluster node.
>
> Signed-off-by: Tuan Phan <tuanphan@os.amperecomputing.com>
> ---
> Changes in v3:
> - Based on the latest ARM ACPI binding at: https://developer.arm.com/documentation/den0093/c/
>
> Changes in v2:
> - Removed IRQF_SHARED.
> - Fixed ACPI runtime detection.
>
> drivers/perf/arm_dsu_pmu.c | 68 ++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 60 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
> index 96ed93c..4be355d 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 +630,51 @@ 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 cpu;
> + struct dsu_pmu *dsu_pmu = (struct dsu_pmu *) platform_get_drvdata(pdev);
> +
> + /*
> + * A dsu pmu node is inside a cluster parent node along with cpu nodes.
> + * We need to find out all cpus that have the same parent with this pmu.
> + */
> + for_each_possible_cpu(cpu) {
> + struct acpi_device *acpi_dev = ACPI_COMPANION(get_cpu_device(cpu));
> +
> + if (acpi_dev &&
> + acpi_dev->parent == ACPI_COMPANION(&pdev->dev)->parent)
> + cpumask_set_cpu(cpu, &dsu_pmu->associated_cpus);
> + }
> +
> + return 0;
> +}
> +
> +static int dsu_pmu_platform_get_cpus(struct platform_device *pdev)
> +{
> + int ret = -ENOENT;
> + struct fwnode_handle *fwnode = dev_fwnode(&pdev->dev);
> +
> + if (IS_ERR_OR_NULL(fwnode))
> + return ret;
> +
> + if (is_of_node(fwnode))
> + ret = dsu_pmu_dt_get_cpus(pdev);
> + else if (is_acpi_device_node(fwnode))
> + ret = dsu_pmu_acpi_get_cpus(pdev);
> +
> + return ret;
> +}
> +
> /*
> * dsu_pmu_probe_pmu: Probe the PMU details on a CPU in the cluster.
> */
> @@ -683,7 +727,9 @@ static int dsu_pmu_device_probe(struct platform_device *pdev)
> if (IS_ERR(dsu_pmu))
> return PTR_ERR(dsu_pmu);
>
> - rc = dsu_pmu_dt_get_cpus(pdev->dev.of_node, &dsu_pmu->associated_cpus);
> + platform_set_drvdata(pdev, dsu_pmu);

Hmm, this is a bit nasty because we haven't finished initialising the
dsu_pmu yet. I think it would actually be cleaner if you kept:

static int dsu_pmu_dt_get_cpus(struct device_node *dev, cpumask_t *mask)

for the DT case and added:

static int dsu_pmu_acpi_get_cpus(struct device *dev, cpumask_t *mask)

for the ACPI case. I suppose the DT case could take the struct device * too
if you wanted the prototypes to be the same.

> + rc = dsu_pmu_platform_get_cpus(pdev);
> if (rc) {
> dev_warn(&pdev->dev, "Failed to parse the CPUs\n");
> return rc;
> @@ -705,7 +751,6 @@ static int dsu_pmu_device_probe(struct platform_device *pdev)
> }
>
> dsu_pmu->irq = irq;
> - platform_set_drvdata(pdev, dsu_pmu);
> rc = cpuhp_state_add_instance(dsu_pmu_cpuhp_state,
> &dsu_pmu->cpuhp_node);
> if (rc)
> @@ -752,11 +797,19 @@ static const struct of_device_id dsu_pmu_of_match[] = {
> { .compatible = "arm,dsu-pmu", },
> {},
> };
> +MODULE_DEVICE_TABLE(of, dsu_pmu_of_match);
> +
> +static const struct acpi_device_id dsu_pmu_acpi_match[] = {
> + { "ARMHD500", 0},
> + {},
> +};
> +MODULE_DEVICE_TABLE(acpi, dsu_pmu_acpi_match);
>
> static struct platform_driver dsu_pmu_driver = {
> .driver = {
> .name = DRVNAME,
> .of_match_table = of_match_ptr(dsu_pmu_of_match),
> + .acpi_match_table = ACPI_PTR(dsu_pmu_acpi_match),
> .suppress_bind_attrs = true,
> },
> .probe = dsu_pmu_device_probe,
> @@ -826,7 +879,6 @@ static void __exit dsu_pmu_exit(void)
> module_init(dsu_pmu_init);
> module_exit(dsu_pmu_exit);
>
> -MODULE_DEVICE_TABLE(of, dsu_pmu_of_match);

Why have you moved this line?

Will

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