// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2017 NXP
 * Copyright 2016 Freescale Semiconductor, Inc.
 */

#include <linux/bitfield.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/perf_event.h>
#include <linux/slab.h>

#define COUNTER_CNTL            0x0
#define COUNTER_READ            0x20

#define COUNTER_DPCR1           0x30

#define CNTL_OVER               0x1
#define CNTL_CLEAR              0x2
#define CNTL_EN                 0x4
#define CNTL_EN_MASK            0xFFFFFFFB
#define CNTL_CLEAR_MASK         0xFFFFFFFD
#define CNTL_OVER_MASK          0xFFFFFFFE

#define CNTL_CSV_SHIFT          24
#define CNTL_CSV_MASK           (0xFF << CNTL_CSV_SHIFT)

#define EVENT_CYCLES_ID         0
#define EVENT_CYCLES_COUNTER    0
#define NUM_COUNTERS            4

#define to_ddr_pmu(p)           container_of(p, struct ddr_pmu, pmu)

#define DDR_PERF_DEV_NAME       "imx8_ddr"
#define DDR_CPUHP_CB_NAME       DDR_PERF_DEV_NAME "_perf_pmu"

static DEFINE_IDA(ddr_ida);

static const struct of_device_id imx_ddr_pmu_dt_ids[] = {
        { .compatible = "fsl,imx8-ddr-pmu",},
        { .compatible = "fsl,imx8m-ddr-pmu",},
        { /* sentinel */ }
};

struct ddr_pmu {
        struct pmu pmu;
        void __iomem *base;
        unsigned int cpu;
        struct  hlist_node node;
        struct  device *dev;
        struct perf_event *events[NUM_COUNTERS];
        int active_events;
        enum cpuhp_state cpuhp_state;
        int irq;
        int id;
};

static ssize_t ddr_perf_cpumask_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct ddr_pmu *pmu = dev_get_drvdata(dev);

        return cpumap_print_to_pagebuf(true, buf, cpumask_of(pmu->cpu));
}

static struct device_attribute ddr_perf_cpumask_attr =
        __ATTR(cpumask, 0444, ddr_perf_cpumask_show, NULL);

static struct attribute *ddr_perf_cpumask_attrs[] = {
        &ddr_perf_cpumask_attr.attr,
        NULL,
};

static struct attribute_group ddr_perf_cpumask_attr_group = {
        .attrs = ddr_perf_cpumask_attrs,
};

static ssize_t
ddr_pmu_event_show(struct device *dev, struct device_attribute *attr,
                   char *page)
{
        struct perf_pmu_events_attr *pmu_attr;

        pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
        return sprintf(page, "event=0x%02llx\n", pmu_attr->id);
}

#define IMX8_DDR_PMU_EVENT_ATTR(_name, _id)                             \
        (&((struct perf_pmu_events_attr[]) {                            \
                { .attr = __ATTR(_name, 0444, ddr_pmu_event_show, NULL),\
                  .id = _id, }                                          \
        })[0].attr.attr)

static struct attribute *ddr_perf_events_attrs[] = {
        IMX8_DDR_PMU_EVENT_ATTR(cycles, EVENT_CYCLES_ID),
        IMX8_DDR_PMU_EVENT_ATTR(selfresh, 0x01),
        IMX8_DDR_PMU_EVENT_ATTR(read-accesses, 0x04),
        IMX8_DDR_PMU_EVENT_ATTR(write-accesses, 0x05),
        IMX8_DDR_PMU_EVENT_ATTR(read-queue-depth, 0x08),
        IMX8_DDR_PMU_EVENT_ATTR(write-queue-depth, 0x09),
        IMX8_DDR_PMU_EVENT_ATTR(lp-read-credit-cnt, 0x10),
        IMX8_DDR_PMU_EVENT_ATTR(hp-read-credit-cnt, 0x11),
        IMX8_DDR_PMU_EVENT_ATTR(write-credit-cnt, 0x12),
        IMX8_DDR_PMU_EVENT_ATTR(read-command, 0x20),
        IMX8_DDR_PMU_EVENT_ATTR(write-command, 0x21),
        IMX8_DDR_PMU_EVENT_ATTR(read-modify-write-command, 0x22),
        IMX8_DDR_PMU_EVENT_ATTR(hp-read, 0x23),
        IMX8_DDR_PMU_EVENT_ATTR(hp-req-nocredit, 0x24),
        IMX8_DDR_PMU_EVENT_ATTR(hp-xact-credit, 0x25),
        IMX8_DDR_PMU_EVENT_ATTR(lp-req-nocredit, 0x26),
        IMX8_DDR_PMU_EVENT_ATTR(lp-xact-credit, 0x27),
        IMX8_DDR_PMU_EVENT_ATTR(wr-xact-credit, 0x29),
        IMX8_DDR_PMU_EVENT_ATTR(read-cycles, 0x2a),
        IMX8_DDR_PMU_EVENT_ATTR(write-cycles, 0x2b),
        IMX8_DDR_PMU_EVENT_ATTR(read-write-transition, 0x30),
        IMX8_DDR_PMU_EVENT_ATTR(precharge, 0x31),
        IMX8_DDR_PMU_EVENT_ATTR(activate, 0x32),
        IMX8_DDR_PMU_EVENT_ATTR(load-mode, 0x33),
        IMX8_DDR_PMU_EVENT_ATTR(perf-mwr, 0x34),
        IMX8_DDR_PMU_EVENT_ATTR(read, 0x35),
        IMX8_DDR_PMU_EVENT_ATTR(read-activate, 0x36),
        IMX8_DDR_PMU_EVENT_ATTR(refresh, 0x37),
        IMX8_DDR_PMU_EVENT_ATTR(write, 0x38),
        IMX8_DDR_PMU_EVENT_ATTR(raw-hazard, 0x39),
        NULL,
};

static struct attribute_group ddr_perf_events_attr_group = {
        .name = "events",
        .attrs = ddr_perf_events_attrs,
};

PMU_FORMAT_ATTR(event, "config:0-7");

static struct attribute *ddr_perf_format_attrs[] = {
        &format_attr_event.attr,
        NULL,
};

static struct attribute_group ddr_perf_format_attr_group = {
        .name = "format",
        .attrs = ddr_perf_format_attrs,
};

static const struct attribute_group *attr_groups[] = {
        &ddr_perf_events_attr_group,
        &ddr_perf_format_attr_group,
        &ddr_perf_cpumask_attr_group,
        NULL,
};

static u32 ddr_perf_alloc_counter(struct ddr_pmu *pmu, int event)
{
        int i;

        /*
         * Always map cycle event to counter 0
         * Cycles counter is dedicated for cycle event
         * can't used for the other events
         */
        if (event == EVENT_CYCLES_ID) {
                if (pmu->events[EVENT_CYCLES_COUNTER] == NULL)
                        return EVENT_CYCLES_COUNTER;
                else
                        return -ENOENT;
        }

        for (i = 1; i < NUM_COUNTERS; i++) {
                if (pmu->events[i] == NULL)
                        return i;
        }

        return -ENOENT;
}

static void ddr_perf_free_counter(struct ddr_pmu *pmu, int counter)
{
        pmu->events[counter] = NULL;
}

static u32 ddr_perf_read_counter(struct ddr_pmu *pmu, int counter)
{
        return readl_relaxed(pmu->base + COUNTER_READ + counter * 4);
}

static int ddr_perf_event_init(struct perf_event *event)
{
        struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        struct perf_event *sibling;

        if (event->attr.type != event->pmu->type)
                return -ENOENT;

        if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
                return -EOPNOTSUPP;

        if (event->cpu < 0) {
                dev_warn(pmu->dev, "Can't provide per-task data!\n");
                return -EOPNOTSUPP;
        }

        /*
         * We must NOT create groups containing mixed PMUs, although software
         * events are acceptable (for example to create a CCN group
         * periodically read when a hrtimer aka cpu-clock leader triggers).
         */
        if (event->group_leader->pmu != event->pmu &&
                        !is_software_event(event->group_leader))
                return -EINVAL;

        for_each_sibling_event(sibling, event->group_leader) {
                if (sibling->pmu != event->pmu &&
                                !is_software_event(sibling))
                        return -EINVAL;
        }

        event->cpu = pmu->cpu;
        hwc->idx = -1;

        return 0;
}


static void ddr_perf_event_update(struct perf_event *event)
{
        struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        u64 delta, prev_raw_count, new_raw_count;
        int counter = hwc->idx;

        do {
                prev_raw_count = local64_read(&hwc->prev_count);
                new_raw_count = ddr_perf_read_counter(pmu, counter);
        } while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
                        new_raw_count) != prev_raw_count);

        delta = (new_raw_count - prev_raw_count) & 0xFFFFFFFF;

        local64_add(delta, &event->count);
}

static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config,
                                  int counter, bool enable)
{
        u8 reg = counter * 4 + COUNTER_CNTL;
        int val;

        if (enable) {
                /*
                 * must disable first, then enable again
                 * otherwise, cycle counter will not work
                 * if previous state is enabled.
                 */
                writel(0, pmu->base + reg);
                val = CNTL_EN | CNTL_CLEAR;
                val |= FIELD_PREP(CNTL_CSV_MASK, config);
                writel(val, pmu->base + reg);
        } else {
                /* Disable counter */
                writel(0, pmu->base + reg);
        }
}

static void ddr_perf_event_start(struct perf_event *event, int flags)
{
        struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        int counter = hwc->idx;

        local64_set(&hwc->prev_count, 0);

        ddr_perf_counter_enable(pmu, event->attr.config, counter, true);

        hwc->state = 0;
}

static int ddr_perf_event_add(struct perf_event *event, int flags)
{
        struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        int counter;
        int cfg = event->attr.config;

        counter = ddr_perf_alloc_counter(pmu, cfg);
        if (counter < 0) {
                dev_dbg(pmu->dev, "There are not enough counters\n");
                return -EOPNOTSUPP;
        }

        pmu->events[counter] = event;
        pmu->active_events++;
        hwc->idx = counter;

        hwc->state |= PERF_HES_STOPPED;

        if (flags & PERF_EF_START)
                ddr_perf_event_start(event, flags);

        return 0;
}

static void ddr_perf_event_stop(struct perf_event *event, int flags)
{
        struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        int counter = hwc->idx;

        ddr_perf_counter_enable(pmu, event->attr.config, counter, false);
        ddr_perf_event_update(event);

        hwc->state |= PERF_HES_STOPPED;
}

static void ddr_perf_event_del(struct perf_event *event, int flags)
{
        struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        int counter = hwc->idx;

        ddr_perf_event_stop(event, PERF_EF_UPDATE);

        ddr_perf_free_counter(pmu, counter);
        pmu->active_events--;
        hwc->idx = -1;
}

static void ddr_perf_pmu_enable(struct pmu *pmu)
{
        struct ddr_pmu *ddr_pmu = to_ddr_pmu(pmu);

        /* enable cycle counter if cycle is not active event list */
        if (ddr_pmu->events[EVENT_CYCLES_COUNTER] == NULL)
                ddr_perf_counter_enable(ddr_pmu,
                                      EVENT_CYCLES_ID,
                                      EVENT_CYCLES_COUNTER,
                                      true);
}

static void ddr_perf_pmu_disable(struct pmu *pmu)
{
        struct ddr_pmu *ddr_pmu = to_ddr_pmu(pmu);

        if (ddr_pmu->events[EVENT_CYCLES_COUNTER] == NULL)
                ddr_perf_counter_enable(ddr_pmu,
                                      EVENT_CYCLES_ID,
                                      EVENT_CYCLES_COUNTER,
                                      false);
}

static int ddr_perf_init(struct ddr_pmu *pmu, void __iomem *base,
                         struct device *dev)
{
        *pmu = (struct ddr_pmu) {
                .pmu = (struct pmu) {
                        .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
                        .task_ctx_nr = perf_invalid_context,
                        .attr_groups = attr_groups,
                        .event_init  = ddr_perf_event_init,
                        .add         = ddr_perf_event_add,
                        .del         = ddr_perf_event_del,
                        .start       = ddr_perf_event_start,
                        .stop        = ddr_perf_event_stop,
                        .read        = ddr_perf_event_update,
                        .pmu_enable  = ddr_perf_pmu_enable,
                        .pmu_disable = ddr_perf_pmu_disable,
                },
                .base = base,
                .dev = dev,
        };

        pmu->id = ida_simple_get(&ddr_ida, 0, 0, GFP_KERNEL);
        return pmu->id;
}

static irqreturn_t ddr_perf_irq_handler(int irq, void *p)
{
        int i;
        struct ddr_pmu *pmu = (struct ddr_pmu *) p;
        struct perf_event *event, *cycle_event = NULL;

        /* all counter will stop if cycle counter disabled */
        ddr_perf_counter_enable(pmu,
                              EVENT_CYCLES_ID,
                              EVENT_CYCLES_COUNTER,
                              false);
        /*
         * When the cycle counter overflows, all counters are stopped,
         * and an IRQ is raised. If any other counter overflows, it
         * continues counting, and no IRQ is raised.
         *
         * Cycles occur at least 4 times as often as other events, so we
         * can update all events on a cycle counter overflow and not
         * lose events.
         *
         */
        for (i = 0; i < NUM_COUNTERS; i++) {

                if (!pmu->events[i])
                        continue;

                event = pmu->events[i];

                ddr_perf_event_update(event);

                if (event->hw.idx == EVENT_CYCLES_COUNTER)
                        cycle_event = event;
        }

        ddr_perf_counter_enable(pmu,
                              EVENT_CYCLES_ID,
                              EVENT_CYCLES_COUNTER,
                              true);
        if (cycle_event)
                ddr_perf_event_update(cycle_event);

        return IRQ_HANDLED;
}

static int ddr_perf_offline_cpu(unsigned int cpu, struct hlist_node *node)
{
        struct ddr_pmu *pmu = hlist_entry_safe(node, struct ddr_pmu, node);
        int target;

        if (cpu != pmu->cpu)
                return 0;

        target = cpumask_any_but(cpu_online_mask, cpu);
        if (target >= nr_cpu_ids)
                return 0;

        perf_pmu_migrate_context(&pmu->pmu, cpu, target);
        pmu->cpu = target;

        WARN_ON(irq_set_affinity_hint(pmu->irq, cpumask_of(pmu->cpu)));

        return 0;
}

static int ddr_perf_probe(struct platform_device *pdev)
{
        struct ddr_pmu *pmu;
        struct device_node *np;
        void __iomem *base;
        char *name;
        int num;
        int ret;
        int irq;

        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return PTR_ERR(base);

        np = pdev->dev.of_node;

        pmu = devm_kzalloc(&pdev->dev, sizeof(*pmu), GFP_KERNEL);
        if (!pmu)
                return -ENOMEM;

        num = ddr_perf_init(pmu, base, &pdev->dev);

        platform_set_drvdata(pdev, pmu);

        name = devm_kasprintf(&pdev->dev, GFP_KERNEL, DDR_PERF_DEV_NAME "%d",
                              num);
        if (!name)
                return -ENOMEM;

        pmu->cpu = raw_smp_processor_id();
        ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
                                      DDR_CPUHP_CB_NAME,
                                      NULL,
                                      ddr_perf_offline_cpu);

        if (ret < 0) {
                dev_err(&pdev->dev, "cpuhp_setup_state_multi failed\n");
                goto ddr_perf_err;
        }

        pmu->cpuhp_state = ret;

        /* Register the pmu instance for cpu hotplug */
        cpuhp_state_add_instance_nocalls(pmu->cpuhp_state, &pmu->node);

        /* Request irq */
        irq = of_irq_get(np, 0);
        if (irq < 0) {
                dev_err(&pdev->dev, "Failed to get irq: %d", irq);
                ret = irq;
                goto ddr_perf_err;
        }

        ret = devm_request_irq(&pdev->dev, irq,
                                        ddr_perf_irq_handler,
                                        IRQF_NOBALANCING | IRQF_NO_THREAD,
                                        DDR_CPUHP_CB_NAME,
                                        pmu);
        if (ret < 0) {
                dev_err(&pdev->dev, "Request irq failed: %d", ret);
                goto ddr_perf_err;
        }

        pmu->irq = irq;
        ret = irq_set_affinity_hint(pmu->irq, cpumask_of(pmu->cpu));
        if (ret) {
                dev_err(pmu->dev, "Failed to set interrupt affinity!\n");
                goto ddr_perf_err;
        }

        ret = perf_pmu_register(&pmu->pmu, name, -1);
        if (ret)
                goto ddr_perf_err;

        return 0;

ddr_perf_err:
        if (pmu->cpuhp_state)
                cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);

        ida_simple_remove(&ddr_ida, pmu->id);
        dev_warn(&pdev->dev, "i.MX8 DDR Perf PMU failed (%d), disabled\n", ret);
        return ret;
}

static int ddr_perf_remove(struct platform_device *pdev)
{
        struct ddr_pmu *pmu = platform_get_drvdata(pdev);

        cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
        irq_set_affinity_hint(pmu->irq, NULL);

        perf_pmu_unregister(&pmu->pmu);

        ida_simple_remove(&ddr_ida, pmu->id);
        return 0;
}

static struct platform_driver imx_ddr_pmu_driver = {
        .driver         = {
                .name   = "imx-ddr-pmu",
                .of_match_table = imx_ddr_pmu_dt_ids,
        },
        .probe          = ddr_perf_probe,
        .remove         = ddr_perf_remove,
};

module_platform_driver(imx_ddr_pmu_driver);
MODULE_LICENSE("GPL v2");