drivers/perf: arm_pmu: split out platform device probe logic

Now that we've split the pdev and DT probing logic from the runtime
management, let's move the former into its own file. We gain a few lines
due to the copyright header and includes, but this should keep the logic
clearly separated, and paves the way for adding ACPI support in a
similar fashion.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
[will: rename nr_irqs to avoid conflict with global variable]
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 235 insertions, 0 deletions

diff --git a/drivers/perf/arm_pmu_platform.c b/drivers/perf/arm_pmu_platform.c
new file mode 100644
index 000000000000..69255f53057a
--- /dev/null
+++ b/drivers/perf/arm_pmu_platform.c
@@ -0,0 +1,235 @@
+/*
+ * platform_device probing code for ARM performance counters.
+ *
+ * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
+ * Copyright (C) 2010 ARM Ltd., Will Deacon <will.deacon@arm.com>
+ */
+#define pr_fmt(fmt) "hw perfevents: " fmt
+
+#include <linux/bug.h>
+#include <linux/cpumask.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/kconfig.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/percpu.h>
+#include <linux/perf/arm_pmu.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/smp.h>
+
+static int probe_current_pmu(struct arm_pmu *pmu,
+			     const struct pmu_probe_info *info)
+{
+	int cpu = get_cpu();
+	unsigned int cpuid = read_cpuid_id();
+	int ret = -ENODEV;
+
+	pr_info("probing PMU on CPU %d\n", cpu);
+
+	for (; info->init != NULL; info++) {
+		if ((cpuid & info->mask) != info->cpuid)
+			continue;
+		ret = info->init(pmu);
+		break;
+	}
+
+	put_cpu();
+	return ret;
+}
+
+static int pmu_parse_percpu_irq(struct arm_pmu *pmu, int irq)
+{
+	int cpu, ret;
+	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
+
+	ret = irq_get_percpu_devid_partition(irq, &pmu->supported_cpus);
+	if (ret)
+		return ret;
+
+	for_each_cpu(cpu, &pmu->supported_cpus)
+		per_cpu(hw_events->irq, cpu) = irq;
+
+	return 0;
+}
+
+static bool pmu_has_irq_affinity(struct device_node *node)
+{
+	return !!of_find_property(node, "interrupt-affinity", NULL);
+}
+
+static int pmu_parse_irq_affinity(struct device_node *node, int i)
+{
+	struct device_node *dn;
+	int cpu;
+
+	/*
+	 * If we don't have an interrupt-affinity property, we guess irq
+	 * affinity matches our logical CPU order, as we used to assume.
+	 * This is fragile, so we'll warn in pmu_parse_irqs().
+	 */
+	if (!pmu_has_irq_affinity(node))
+		return i;
+
+	dn = of_parse_phandle(node, "interrupt-affinity", i);
+	if (!dn) {
+		pr_warn("failed to parse interrupt-affinity[%d] for %s\n",
+			i, node->name);
+		return -EINVAL;
+	}
+
+	/* Now look up the logical CPU number */
+	for_each_possible_cpu(cpu) {
+		struct device_node *cpu_dn;
+
+		cpu_dn = of_cpu_device_node_get(cpu);
+		of_node_put(cpu_dn);
+
+		if (dn == cpu_dn)
+			break;
+	}
+
+	if (cpu >= nr_cpu_ids) {
+		pr_warn("failed to find logical CPU for %s\n", dn->name);
+	}
+
+	of_node_put(dn);
+
+	return cpu;
+}
+
+static int pmu_parse_irqs(struct arm_pmu *pmu)
+{
+	int i = 0, num_irqs;
+	struct platform_device *pdev = pmu->plat_device;
+	struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
+
+	num_irqs = platform_irq_count(pdev);
+	if (num_irqs < 0) {
+		pr_err("unable to count PMU IRQs\n");
+		return num_irqs;
+	}
+
+	/*
+	 * In this case we have no idea which CPUs are covered by the PMU.
+	 * To match our prior behaviour, we assume all CPUs in this case.
+	 */
+	if (num_irqs == 0) {
+		pr_warn("no irqs for PMU, sampling events not supported\n");
+		pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
+		cpumask_setall(&pmu->supported_cpus);
+		return 0;
+	}
+
+	if (num_irqs == 1) {
+		int irq = platform_get_irq(pdev, 0);
+		if (irq && irq_is_percpu(irq))
+			return pmu_parse_percpu_irq(pmu, irq);
+	}
+
+	if (!pmu_has_irq_affinity(pdev->dev.of_node)) {
+		pr_warn("no interrupt-affinity property for %s, guessing.\n",
+			of_node_full_name(pdev->dev.of_node));
+	}
+
+	/*
+	 * Some platforms have all PMU IRQs OR'd into a single IRQ, with a
+	 * special platdata function that attempts to demux them.
+	 */
+	if (dev_get_platdata(&pdev->dev))
+		cpumask_setall(&pmu->supported_cpus);
+
+	for (i = 0; i < num_irqs; i++) {
+		int cpu, irq;
+
+		irq = platform_get_irq(pdev, i);
+		if (WARN_ON(irq <= 0))
+			continue;
+
+		if (irq_is_percpu(irq)) {
+			pr_warn("multiple PPIs or mismatched SPI/PPI detected\n");
+			return -EINVAL;
+		}
+
+		cpu = pmu_parse_irq_affinity(pdev->dev.of_node, i);
+		if (cpu < 0)
+			return cpu;
+		if (cpu >= nr_cpu_ids)
+			continue;
+
+		if (per_cpu(hw_events->irq, cpu)) {
+			pr_warn("multiple PMU IRQs for the same CPU detected\n");
+			return -EINVAL;
+		}
+
+		per_cpu(hw_events->irq, cpu) = irq;
+		cpumask_set_cpu(cpu, &pmu->supported_cpus);
+	}
+
+	return 0;
+}
+
+int arm_pmu_device_probe(struct platform_device *pdev,
+			 const struct of_device_id *of_table,
+			 const struct pmu_probe_info *probe_table)
+{
+	const struct of_device_id *of_id;
+	armpmu_init_fn init_fn;
+	struct device_node *node = pdev->dev.of_node;
+	struct arm_pmu *pmu;
+	int ret = -ENODEV;
+
+	pmu = armpmu_alloc();
+	if (!pmu)
+		return -ENOMEM;
+
+	pmu->plat_device = pdev;
+
+	ret = pmu_parse_irqs(pmu);
+	if (ret)
+		goto out_free;
+
+	if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) {
+		init_fn = of_id->data;
+
+		pmu->secure_access = of_property_read_bool(pdev->dev.of_node,
+							   "secure-reg-access");
+
+		/* arm64 systems boot only as non-secure */
+		if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
+			pr_warn("ignoring \"secure-reg-access\" property for arm64\n");
+			pmu->secure_access = false;
+		}
+
+		ret = init_fn(pmu);
+	} else if (probe_table) {
+		cpumask_setall(&pmu->supported_cpus);
+		ret = probe_current_pmu(pmu, probe_table);
+	}
+
+	if (ret) {
+		pr_info("%s: failed to probe PMU!\n", of_node_full_name(node));
+		goto out_free;
+	}
+
+	ret = armpmu_request_irqs(pmu);
+	if (ret)
+		goto out_free_irqs;
+
+	ret = armpmu_register(pmu);
+	if (ret)
+		goto out_free;
+
+	return 0;
+
+out_free_irqs:
+	armpmu_free_irqs(pmu);
+out_free:
+	pr_info("%s: failed to register PMU devices!\n",
+		of_node_full_name(node));
+	armpmu_free(pmu);
+	return ret;
+}