Messages in this thread | | | Subject | Re: [PATCH 2/2] perf: arm_dsu: Support DSU ACPI devices. | From | Suzuki K Poulose <> | Date | Thu, 19 Mar 2020 00:45:37 +0000 |
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Hello,
Please find my comments below.
On 03/18/2020 12:28 AM, Tuan Phan wrote: > Add support for probing device from ACPI node. > Each DSU ACPI node defines "cpus" package which > each element is the MPIDR of associated cpu. > > Signed-off-by: Tuan Phan <tuanphan@os.amperecomputing.com> > --- > drivers/perf/arm_dsu_pmu.c | 53 +++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 45 insertions(+), 8 deletions(-) > > diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c Tua > index 2622900..6ef762c 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 +604,22 @@ 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_get_cpus: Get the list of CPUs in the cluster. > */ > -static int dsu_pmu_dt_get_cpus(struct device_node *dev, cpumask_t *mask) > +static int dsu_pmu_get_cpus(struct platform_device *pdev) > { > +#ifndef CONFIG_ACPI > + /* Get the list of CPUs from device tree */
What if we have a kernel with both:
CONFIG_OF=y CONFIG_ACPI=y
and boot the kernel on a system with DT ? In other words, the decision to choose the DT vs ACPI must be runtime decision, not buildtime.
See drivers/hwtracing/coresight/coresight-platform.c:coresight_get_platform_data() for an example.
> 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); > @@ -626,9 +631,33 @@ 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; > +#else /* CONFIG_ACPI */ > + 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_ANY, &obj);
Is the binding documented somewhere ?
nit: Also, why not : ret = acpi_dev_get_propert(adev, "cpus", ACPI_TYPE_PACKAGE, &obj); if (ret < 0) return ret; ?
> + if (ret < 0) > + return -EINVAL; > + > + if (obj->type != ACPI_TYPE_PACKAGE) > + return -EINVAL; > + > + for (i = 0; i < obj->package.count; i++) {
> + /* Each element is the MPIDR of associated cpu */ > + for_each_possible_cpu(cpu) { > + if (cpu_physical_id(cpu) == > + obj->package.elements[i].integer.value) > + cpumask_set_cpu(cpu, &dsu_pmu->associated_cpus); > + } > + } > + return 0; > +#endif > } >
Otherwise looks good to me.
Suzuki
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