arm64: pmu: add fallback probe table

In preparation for ACPI support, add a pmu_probe_info table to
the arm_pmu_device_probe() call. This table gets used when
probing in the absence of a devicetree node for PMU.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/perf_event.c

@@ -24,6 +24,7 @@
 #include <asm/sysreg.h>
 #include <asm/virt.h>
 
+#include <linux/acpi.h>
 #include <linux/of.h>
 #include <linux/perf/arm_pmu.h>
 #include <linux/platform_device.h>
@@ -1056,9 +1057,19 @@ static const struct of_device_id armv8_pmu_of_device_ids[] = {
 	{},
 };
 
+static const struct pmu_probe_info armv8_pmu_probe_table[] = {
+	PMU_PROBE(0, 0, armv8_pmuv3_init), /* if all else fails... */
+	{ /* sentinel value */ }
+};
+
 static int armv8_pmu_device_probe(struct platform_device *pdev)
 {
-	return arm_pmu_device_probe(pdev, armv8_pmu_of_device_ids, NULL);
+	if (acpi_disabled)
+		return arm_pmu_device_probe(pdev, armv8_pmu_of_device_ids,
+					    NULL);
+
+	return arm_pmu_device_probe(pdev, armv8_pmu_of_device_ids,
+				    armv8_pmu_probe_table);
 }
 
 static struct platform_driver armv8_pmu_driver = {

drivers/perf/arm_pmu.c

@@ -1048,7 +1048,7 @@ int arm_pmu_device_probe(struct platform_device *pdev,
 		ret = of_pmu_irq_cfg(pmu);
 		if (!ret)
 			ret = init_fn(pmu);
-	} else {
+	} else if (probe_table) {
 		cpumask_setall(&pmu->supported_cpus);
 		ret = probe_current_pmu(pmu, probe_table);
 	}