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Commit d5efd9cc authored by Will Deacon's avatar Will Deacon
Browse files

arm64: 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 71bbf038

arch/arm64/include/asm/pmu.h

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ struct pmu_hw_events { 
struct arm_pmu {

	struct pmu		pmu;

	cpumask_t		active_irqs;

	int			*irq_affinity;

	const char		*name;

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

	void			(*enable)(struct hw_perf_event *evt, int idx);

arch/arm64/kernel/perf_event.c

+53 −4
Original line number Diff line number Diff line
@@ -25,8 +25,10 @@ 
#include <linux/irq.h>

#include <linux/kernel.h>

#include <linux/export.h>

#include <linux/of.h>

#include <linux/perf_event.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/uaccess.h>
@@ -405,7 +407,12 @@ armpmu_release_hardware(struct arm_pmu *armpmu) 
		free_percpu_irq(irq, &cpu_hw_events);

	} else {

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

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

			int cpu = i;



			if (armpmu->irq_affinity)

				cpu = armpmu->irq_affinity[i];



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

				continue;

			irq = platform_get_irq(pmu_device, i);

			if (irq > 0)
@@ -459,19 +466,24 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu) 
		on_each_cpu(armpmu_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 (armpmu->irq_affinity)

				cpu = armpmu->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_warning("unable to set irq affinity (irq=%d, cpu=%u)\n",

						irq, i);

						irq, cpu);

				continue;

			}
@@ -485,7 +497,7 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu) 
				return err;

			}



			cpumask_set_cpu(i, &armpmu->active_irqs);

			cpumask_set_cpu(cpu, &armpmu->active_irqs);

		}

	}
@@ -1298,9 +1310,46 @@ static const struct of_device_id armpmu_of_device_ids[] = { 


static int armpmu_device_probe(struct platform_device *pdev)

{

	int i, *irqs;



	if (!cpu_pmu)

		return -ENODEV;



	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);



	cpu_pmu->plat_device = pdev;

	return 0;

}