Messages in this thread | | | Subject | Re: [PATCH 2/2] perf: arm_dsu: Support DSU ACPI devices. | From | Tuan Phan <> | Date | Thu, 19 Mar 2020 15:49:12 -0700 |
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Hi Suzuki,
> On Mar 18, 2020, at 5:45 PM, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > 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; > ? => I couldn’t find the device tree binding document of DSU anywhere. Is It enough to put a comment describing the acpi binding in the code or need somewhere else? > > >> + 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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