// SPDX-License-Identifier: GPL-2.0
/*
 * 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
#define dev_fmt pr_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/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,
                                const struct cpumask *affinity)
{
        struct pmu_hw_events __percpu *hw_events = pmu->hw_events;
        int cpu;

        cpumask_copy(&pmu->supported_cpus, affinity);

        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_property_present(node, "interrupt-affinity");
}

static int pmu_parse_irq_affinity(struct device *dev, 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(dev->of_node))
                return i;

        dn = of_parse_phandle(dev->of_node, "interrupt-affinity", i);
        if (!dn) {
                dev_warn(dev, "failed to parse interrupt-affinity[%d]\n", i);
                return -EINVAL;
        }

        cpu = of_cpu_node_to_id(dn);
        if (cpu < 0) {
                dev_warn(dev, "failed to find logical CPU for %pOFn\n", dn);
                cpu = nr_cpu_ids;
        }

        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;
        struct device *dev = &pdev->dev;

        num_irqs = platform_irq_count(pdev);
        if (num_irqs < 0)
                return dev_err_probe(dev, num_irqs, "unable to count PMU IRQs\n");

        /*
         * 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) {
                dev_warn(dev, "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) {
                const struct cpumask *affinity;
                int irq;

                irq = platform_get_irq_affinity(pdev, 0, &affinity);
                if ((irq > 0) && irq_is_percpu_devid(irq))
                        return pmu_parse_percpu_irq(pmu, irq, affinity);
        }

        if (nr_cpu_ids != 1 && !pmu_has_irq_affinity(dev->of_node))
                dev_warn(dev, "no interrupt-affinity property, guessing.\n");

        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_devid(irq)) {
                        dev_warn(dev, "multiple PPIs or mismatched SPI/PPI detected\n");
                        return -EINVAL;
                }

                cpu = pmu_parse_irq_affinity(dev, i);
                if (cpu < 0)
                        return cpu;
                if (cpu >= nr_cpu_ids)
                        continue;

                if (per_cpu(hw_events->irq, cpu)) {
                        dev_warn(dev, "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;
}

static int armpmu_request_irqs(struct arm_pmu *armpmu)
{
        struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;
        int cpu, err = 0;

        for_each_cpu(cpu, &armpmu->supported_cpus) {
                int irq = per_cpu(hw_events->irq, cpu);
                if (!irq)
                        continue;

                err = armpmu_request_irq(&hw_events->percpu_pmu, irq, cpu);
                if (err)
                        break;
        }

        return err;
}

static void armpmu_free_irqs(struct arm_pmu *armpmu)
{
        int cpu;
        struct pmu_hw_events __percpu *hw_events = armpmu->hw_events;

        for_each_cpu(cpu, &armpmu->supported_cpus) {
                int irq = per_cpu(hw_events->irq, cpu);

                armpmu_free_irq(&hw_events->percpu_pmu, irq, cpu);
        }
}

int arm_pmu_device_probe(struct platform_device *pdev,
                         const struct of_device_id *of_table,
                         const struct pmu_probe_info *probe_table)
{
        armpmu_init_fn init_fn;
        struct device *dev = &pdev->dev;
        struct arm_pmu *pmu;
        int ret = -ENODEV;

        pmu = armpmu_alloc();
        if (!pmu)
                return -ENOMEM;

        pmu->pmu.parent = &pdev->dev;
        pmu->plat_device = pdev;

        ret = pmu_parse_irqs(pmu);
        if (ret)
                goto out_free;

        init_fn = of_device_get_match_data(dev);
        if (init_fn) {
                pmu->secure_access = of_property_read_bool(dev->of_node,
                                                           "secure-reg-access");

                /* arm64 systems boot only as non-secure */
                if (IS_ENABLED(CONFIG_ARM64) && pmu->secure_access) {
                        dev_warn(dev, "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) {
                dev_err(dev, "failed to probe PMU!\n");
                goto out_free;
        }

        ret = armpmu_request_irqs(pmu);
        if (ret)
                goto out_free_irqs;

        ret = armpmu_register(pmu);
        if (ret) {
                dev_err(dev, "failed to register PMU devices!\n");
                goto out_free_irqs;
        }

        return 0;

out_free_irqs:
        armpmu_free_irqs(pmu);
out_free:
        armpmu_free(pmu);
        return ret;
}