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Commit 9fd85eb5 authored by Will Deacon's avatar Will Deacon
Browse files

ARM: pmu: add support for interrupt-affinity property 



Historically, the PMU devicetree bindings have expected SPIs to be
listed in order of *logical* CPU number. This is problematic for
bootloaders, especially when the boot CPU (logical ID 0) isn't listed
first in the devicetree.

This patch adds a new optional property, interrupt-affinity, to the
PMU node which allows the interrupt affinity to be described using
a list of phandled to CPU nodes, with each entry in the list
corresponding to the SPI at the same index in the interrupts property.

Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent e429817b

arch/arm/include/asm/pmu.h

+1 −0
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ struct pmu_hw_events { 
struct arm_pmu {

	struct pmu	pmu;

	cpumask_t	active_irqs;

	int		*irq_affinity;

	char		*name;

	irqreturn_t	(*handle_irq)(int irq_num, void *dev);

	void		(*enable)(struct perf_event *event);

arch/arm/kernel/perf_event_cpu.c

+62 −7
Original line number Diff line number Diff line
@@ -92,11 +92,16 @@ static void cpu_pmu_free_irq(struct arm_pmu *cpu_pmu) 
		free_percpu_irq(irq, &hw_events->percpu_pmu);

	} else {

		for (i = 0; i < irqs; ++i) {

			if (!cpumask_test_and_clear_cpu(i, &cpu_pmu->active_irqs))

			int cpu = i;



			if (cpu_pmu->irq_affinity)

				cpu = cpu_pmu->irq_affinity[i];



			if (!cpumask_test_and_clear_cpu(cpu, &cpu_pmu->active_irqs))

				continue;

			irq = platform_get_irq(pmu_device, i);

			if (irq >= 0)

				free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, i));

				free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu));

		}

	}

}
@@ -128,32 +133,37 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler) 
		on_each_cpu(cpu_pmu_enable_percpu_irq, &irq, 1);

	} else {

		for (i = 0; i < irqs; ++i) {

			int cpu = i;



			err = 0;

			irq = platform_get_irq(pmu_device, i);

			if (irq < 0)

				continue;



			if (cpu_pmu->irq_affinity)

				cpu = cpu_pmu->irq_affinity[i];



			/*

			 * If we have a single PMU interrupt that we can't shift,

			 * assume that we're running on a uniprocessor machine and

			 * continue. Otherwise, continue without this interrupt.

			 */

			if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) {

			if (irq_set_affinity(irq, cpumask_of(cpu)) && irqs > 1) {

				pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",

					irq, i);

					irq, cpu);

				continue;

			}



			err = request_irq(irq, handler,

					  IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",

					  per_cpu_ptr(&hw_events->percpu_pmu, i));

					  per_cpu_ptr(&hw_events->percpu_pmu, cpu));

			if (err) {

				pr_err("unable to request IRQ%d for ARM PMU counters\n",

					irq);

				return err;

			}



			cpumask_set_cpu(i, &cpu_pmu->active_irqs);

			cpumask_set_cpu(cpu, &cpu_pmu->active_irqs);

		}

	}
@@ -291,6 +301,48 @@ static int probe_current_pmu(struct arm_pmu *pmu) 
	return ret;

}



static int of_pmu_irq_cfg(struct platform_device *pdev)

{

	int i;

	int *irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);



	if (!irqs)

		return -ENOMEM;



	for (i = 0; i < pdev->num_resources; ++i) {

		struct device_node *dn;

		int cpu;



		dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity",

				      i);

		if (!dn) {

			pr_warn("Failed to parse %s/interrupt-affinity[%d]\n",

				of_node_full_name(dn), i);

			break;

		}



		for_each_possible_cpu(cpu)

			if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL))

				break;



		of_node_put(dn);

		if (cpu >= nr_cpu_ids) {

			pr_warn("Failed to find logical CPU for %s\n",

				dn->name);

			break;

		}



		irqs[i] = cpu;

	}



	if (i == pdev->num_resources)

		cpu_pmu->irq_affinity = irqs;

	else

		kfree(irqs);



	return 0;

}



static int cpu_pmu_device_probe(struct platform_device *pdev)

{

	const struct of_device_id *of_id;
@@ -315,6 +367,9 @@ static int cpu_pmu_device_probe(struct platform_device *pdev) 


	if (node && (of_id = of_match_node(cpu_pmu_of_device_ids, pdev->dev.of_node))) {

		init_fn = of_id->data;



		ret = of_pmu_irq_cfg(pdev);

		if (!ret)

			ret = init_fn(pmu);

	} else {

		ret = probe_current_pmu(pmu);