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@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
---
Documentation/devicetree/bindings/arm/pmu.txt | 6 +++
arch/arm64/include/asm/pmu.h | 1 +
arch/arm64/kernel/perf_event.c | 57 +++++++++++++++++++++++++--
3 files changed, 60 insertions(+), 4 deletions(-)
diff --git a/Documentation/devicetree/bindings/arm/pmu.txt b/Documentation/devicetree/bindings/arm/pmu.txt
index 75ef91d08f3b..a9281fc48743 100644
--- a/Documentation/devicetree/bindings/arm/pmu.txt
+++ b/Documentation/devicetree/bindings/arm/pmu.txt
@@ -24,6 +24,12 @@ Required properties:
Optional properties:
+- interrupt-affinity : Valid only when using SPIs, specifies a list of phandles
+ to CPU nodes corresponding directly to the affinity of
+ the SPIs listed in the interrupts property. If absent,
+ the interrupts are assumed to be listed in logical CPU
+ order.
+
- qcom,no-pc-write : Indicates that this PMU doesn't support the 0xc and 0xd
events.
diff --git a/arch/arm64/include/asm/pmu.h b/arch/arm64/include/asm/pmu.h
index e6f087806aaf..b7710a59672c 100644
--- a/arch/arm64/include/asm/pmu.h
+++ b/arch/arm64/include/asm/pmu.h
@@ -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);
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 25a5308744b1..19821d936e75 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -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>
@@ -396,7 +398,12 @@ 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 (arm_pmu->irq_affinity)
+ cpu = arm_pmu->irq_affinity[i];
+
+ if (!cpumask_test_and_clear_cpu(cpu, &armpmu->active_irqs))
continue;
irq = platform_get_irq(pmu_device, i);
if (irq > 0)
@@ -450,19 +457,24 @@ 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;
}
@@ -476,7 +488,7 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu)
return err;
}
- cpumask_set_cpu(i, &armpmu->active_irqs);
+ cpumask_set_cpu(cpu, &armpmu->active_irqs);
}
}
@@ -1289,9 +1301,46 @@ 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 = -1;
+
+ dn = of_parse_phandle(pdev->dev.of_node, "interrupt-affinity",
+ i);
+ if (!dn) {
+ pr_warn("Failed to parse interrupt-affinity for idx %d\n",
+ i);
+ break;
+ }
+
+ for_each_possible_cpu(cpu)
+ if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL))
+ break;
+
+ if (cpu == -1) {
+ pr_warn("Failed to find logical CPU for %s\n",
+ dn->name);
+ break;
+ }
+
+ irqs[i] = cpu;
+ of_node_put(dn);
+ }
+
+ if (i == pdev->num_resources)
+ cpu_pmu->irq_affinity = irqs;
+ else
+ kfree(irqs);
+
cpu_pmu->plat_device = pdev;
return 0;
}
--
2.1.4
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