[PATCH] arm64/perf: add ACPI support

From: Mark Salter
Date: Fri May 01 2015 - 10:46:13 EST


When using ACPI, the perf_event irq info needs to be parsed
from the MADT and a corresponding platform device needs to
be created and registered. The only change to the existing
driver is a check to avoid unnecessary devicetree parsing.

Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
---
arch/arm64/kernel/perf_event.c | 106 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 106 insertions(+)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 195991d..1e53b26 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -31,6 +31,7 @@
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
+#include <linux/acpi.h>

#include <asm/cputype.h>
#include <asm/irq.h>
@@ -1315,6 +1316,10 @@ static int armpmu_device_probe(struct platform_device *pdev)
if (!cpu_pmu)
return -ENODEV;

+ /* skip the devicetree parsing if we're using ACPI */
+ if (!acpi_disabled)
+ goto done;
+
irqs = kcalloc(pdev->num_resources, sizeof(*irqs), GFP_KERNEL);
if (!irqs)
return -ENOMEM;
@@ -1350,6 +1355,7 @@ static int armpmu_device_probe(struct platform_device *pdev)
else
kfree(irqs);

+done:
cpu_pmu->plat_device = pdev;
return 0;
}
@@ -1368,6 +1374,106 @@ static int __init register_pmu_driver(void)
}
device_initcall(register_pmu_driver);

+#ifdef CONFIG_ACPI
+struct acpi_pmu_irq {
+ int gsi;
+ int trigger;
+};
+
+static struct acpi_pmu_irq acpi_pmu_irqs[NR_CPUS] __initdata;
+
+static int __init
+acpi_parse_pmu_irqs(struct acpi_subtable_header *header,
+ const unsigned long end)
+{
+ struct acpi_madt_generic_interrupt *gic;
+ int cpu;
+ u64 mpidr;
+
+ gic = (struct acpi_madt_generic_interrupt *)header;
+ if (BAD_MADT_ENTRY(gic, end))
+ return -EINVAL;
+
+ mpidr = gic->arm_mpidr & MPIDR_HWID_BITMASK;
+
+ for_each_possible_cpu(cpu) {
+ if (cpu_logical_map(cpu) != mpidr)
+ continue;
+
+ acpi_pmu_irqs[cpu].gsi = gic->performance_interrupt;
+ if (gic->flags & ACPI_MADT_PERFORMANCE_IRQ_MODE)
+ acpi_pmu_irqs[cpu].trigger = ACPI_EDGE_SENSITIVE;
+ else
+ acpi_pmu_irqs[cpu].trigger = ACPI_LEVEL_SENSITIVE;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int __init pmu_acpi_init(void)
+{
+ struct platform_device *pdev;
+ struct acpi_pmu_irq *pirq = acpi_pmu_irqs;
+ struct resource *res, *r;
+ int err = -ENOMEM;
+ int i, count, irq;
+
+ if (acpi_disabled)
+ return 0;
+
+ count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
+ acpi_parse_pmu_irqs, num_possible_cpus());
+ /* Must have irq for boot boot cpu, at least */
+ if (count <= 0 || pirq->gsi == 0)
+ return -EINVAL;
+
+ irq = acpi_register_gsi(NULL, pirq->gsi, pirq->trigger,
+ ACPI_ACTIVE_HIGH);
+
+ if (irq_is_percpu(irq))
+ count = 1;
+
+ pdev = platform_device_alloc("arm-pmu", -1);
+ if (!pdev)
+ goto err_free_gsi;
+
+ res = kcalloc(count, sizeof(*res), GFP_KERNEL);
+ if (!res)
+ goto err_free_device;
+
+ for (i = 0, r = res; i < count; i++, pirq++, r++) {
+ if (i)
+ irq = acpi_register_gsi(NULL, pirq->gsi, pirq->trigger,
+ ACPI_ACTIVE_HIGH);
+ r->start = r->end = irq;
+ r->flags = IORESOURCE_IRQ;
+ if (pirq->trigger == ACPI_EDGE_SENSITIVE)
+ r->flags |= IORESOURCE_IRQ_HIGHEDGE;
+ else
+ r->flags |= IORESOURCE_IRQ_HIGHLEVEL;
+ }
+
+ err = platform_device_add_resources(pdev, res, count);
+ if (!err)
+ err = platform_device_add(pdev);
+ kfree(res);
+ if (!err)
+ return 0;
+
+err_free_device:
+ platform_device_put(pdev);
+
+err_free_gsi:
+ for (i = 0; i < count; i++)
+ acpi_unregister_gsi(acpi_pmu_irqs[i].gsi);
+
+ return err;
+}
+arch_initcall(pmu_acpi_init);
+
+#endif /* ACPI */
+
static struct pmu_hw_events *armpmu_get_cpu_events(void)
{
return this_cpu_ptr(&cpu_hw_events);
--
1.8.3.1

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