// SPDX-License-Identifier: GPL-2.0
/*
 * ARM CoreSight Architecture PMU driver.
 *
 * This driver adds support for uncore PMU based on ARM CoreSight Performance
 * Monitoring Unit Architecture. The PMU is accessible via MMIO registers and
 * like other uncore PMUs, it does not support process specific events and
 * cannot be used in sampling mode.
 *
 * This code is based on other uncore PMUs like ARM DSU PMU. It provides a
 * generic implementation to operate the PMU according to CoreSight PMU
 * architecture and ACPI ARM PMU table (APMT) documents below:
 *   - ARM CoreSight PMU architecture document number: ARM IHI 0091 A.a-00bet0.
 *   - APMT document number: ARM DEN0117.
 *
 * The user should refer to the vendor technical documentation to get details
 * about the supported events.
 *
 * Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 *
 */

#include <linux/acpi.h>
#include <linux/cacheinfo.h>
#include <linux/ctype.h>
#include <linux/interrupt.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>

#include "arm_cspmu.h"

#define PMUNAME "arm_cspmu"
#define DRVNAME "arm-cs-arch-pmu"

#define ARM_CSPMU_CPUMASK_ATTR(_name, _config)                  \
        ARM_CSPMU_EXT_ATTR(_name, arm_cspmu_cpumask_show,       \
                                (unsigned long)_config)

/* Each SET/CLR register supports up to 32 counters. */
#define ARM_CSPMU_SET_CLR_COUNTER_SHIFT         5
#define ARM_CSPMU_SET_CLR_COUNTER_NUM           \
        (1 << ARM_CSPMU_SET_CLR_COUNTER_SHIFT)

/* Convert counter idx into SET/CLR register number. */
#define COUNTER_TO_SET_CLR_ID(idx)                      \
        (idx >> ARM_CSPMU_SET_CLR_COUNTER_SHIFT)

/* Convert counter idx into SET/CLR register bit. */
#define COUNTER_TO_SET_CLR_BIT(idx)                     \
        (idx & (ARM_CSPMU_SET_CLR_COUNTER_NUM - 1))

#define ARM_CSPMU_ACTIVE_CPU_MASK               0x0
#define ARM_CSPMU_ASSOCIATED_CPU_MASK           0x1

/*
 * Maximum poll count for reading counter value using high-low-high sequence.
 */
#define HILOHI_MAX_POLL 1000

static unsigned long arm_cspmu_cpuhp_state;

static DEFINE_MUTEX(arm_cspmu_lock);

static void arm_cspmu_set_ev_filter(struct arm_cspmu *cspmu,
                                    const struct perf_event *event);
static void arm_cspmu_set_cc_filter(struct arm_cspmu *cspmu,
                                    const struct perf_event *event);

static struct acpi_apmt_node *arm_cspmu_apmt_node(struct device *dev)
{
        struct acpi_apmt_node **ptr = dev_get_platdata(dev);

        return ptr ? *ptr : NULL;
}

/*
 * In CoreSight PMU architecture, all of the MMIO registers are 32-bit except
 * counter register. The counter register can be implemented as 32-bit or 64-bit
 * register depending on the value of PMCFGR.SIZE field. For 64-bit access,
 * single-copy 64-bit atomic support is implementation defined. APMT node flag
 * is used to identify if the PMU supports 64-bit single copy atomic. If 64-bit
 * single copy atomic is not supported, the driver treats the register as a pair
 * of 32-bit register.
 */

/*
 * Read 64-bit register as a pair of 32-bit registers using hi-lo-hi sequence.
 */
static u64 read_reg64_hilohi(const void __iomem *addr, u32 max_poll_count)
{
        u32 val_lo, val_hi;
        u64 val;

        /* Use high-low-high sequence to avoid tearing */
        do {
                if (max_poll_count-- == 0) {
                        pr_err("ARM CSPMU: timeout hi-low-high sequence\n");
                        return 0;
                }

                val_hi = readl(addr + 4);
                val_lo = readl(addr);
        } while (val_hi != readl(addr + 4));

        val = (((u64)val_hi << 32) | val_lo);

        return val;
}

/* Check if cycle counter is supported. */
static inline bool supports_cycle_counter(const struct arm_cspmu *cspmu)
{
        return (cspmu->pmcfgr & PMCFGR_CC);
}

/* Get counter size, which is (PMCFGR_SIZE + 1). */
static inline u32 counter_size(const struct arm_cspmu *cspmu)
{
        return FIELD_GET(PMCFGR_SIZE, cspmu->pmcfgr) + 1;
}

/* Get counter mask. */
static inline u64 counter_mask(const struct arm_cspmu *cspmu)
{
        return GENMASK_ULL(counter_size(cspmu) - 1, 0);
}

/* Check if counter is implemented as 64-bit register. */
static inline bool use_64b_counter_reg(const struct arm_cspmu *cspmu)
{
        return (counter_size(cspmu) > 32);
}

ssize_t arm_cspmu_sysfs_event_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct perf_pmu_events_attr *pmu_attr;

        pmu_attr = container_of(attr, typeof(*pmu_attr), attr);
        return sysfs_emit(buf, "event=0x%llx\n", pmu_attr->id);
}
EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_event_show);

/* Default event list. */
static struct attribute *arm_cspmu_event_attrs[] = {
        ARM_CSPMU_EVENT_ATTR(cycles, ARM_CSPMU_EVT_CYCLES_DEFAULT),
        NULL,
};

static struct attribute **
arm_cspmu_get_event_attrs(const struct arm_cspmu *cspmu)
{
        struct attribute **attrs;

        attrs = devm_kmemdup(cspmu->dev, arm_cspmu_event_attrs,
                sizeof(arm_cspmu_event_attrs), GFP_KERNEL);

        return attrs;
}

static umode_t
arm_cspmu_event_attr_is_visible(struct kobject *kobj,
                                struct attribute *attr, int unused)
{
        struct device *dev = kobj_to_dev(kobj);
        struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));
        struct perf_pmu_events_attr *eattr;

        eattr = container_of(attr, typeof(*eattr), attr.attr);

        /* Hide cycle event if not supported */
        if (!supports_cycle_counter(cspmu) &&
            eattr->id == ARM_CSPMU_EVT_CYCLES_DEFAULT)
                return 0;

        return attr->mode;
}

static struct attribute *arm_cspmu_format_attrs[] = {
        ARM_CSPMU_FORMAT_EVENT_ATTR,
        ARM_CSPMU_FORMAT_FILTER_ATTR,
        ARM_CSPMU_FORMAT_FILTER2_ATTR,
        NULL,
};

static struct attribute **
arm_cspmu_get_format_attrs(const struct arm_cspmu *cspmu)
{
        struct attribute **attrs;

        attrs = devm_kmemdup(cspmu->dev, arm_cspmu_format_attrs,
                sizeof(arm_cspmu_format_attrs), GFP_KERNEL);

        return attrs;
}

static u32 arm_cspmu_event_type(const struct perf_event *event)
{
        return event->attr.config & ARM_CSPMU_EVENT_MASK;
}

static bool arm_cspmu_is_cycle_counter_event(const struct perf_event *event)
{
        return (event->attr.config == ARM_CSPMU_EVT_CYCLES_DEFAULT);
}

static ssize_t arm_cspmu_identifier_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *page)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));

        return sysfs_emit(page, "%s\n", cspmu->identifier);
}

static struct device_attribute arm_cspmu_identifier_attr =
        __ATTR(identifier, 0444, arm_cspmu_identifier_show, NULL);

static struct attribute *arm_cspmu_identifier_attrs[] = {
        &arm_cspmu_identifier_attr.attr,
        NULL,
};

static struct attribute_group arm_cspmu_identifier_attr_group = {
        .attrs = arm_cspmu_identifier_attrs,
};

static const char *arm_cspmu_get_identifier(const struct arm_cspmu *cspmu)
{
        const char *identifier =
                devm_kasprintf(cspmu->dev, GFP_KERNEL, "%x",
                               cspmu->impl.pmiidr);
        return identifier;
}

static const char *arm_cspmu_type_str[ACPI_APMT_NODE_TYPE_COUNT] = {
        "mc",
        "smmu",
        "pcie",
        "acpi",
        "cache",
};

static const char *arm_cspmu_get_name(const struct arm_cspmu *cspmu)
{
        struct device *dev;
        struct acpi_apmt_node *apmt_node;
        u8 pmu_type;
        char *name;
        char acpi_hid_string[ACPI_ID_LEN] = { 0 };
        static atomic_t pmu_idx[ACPI_APMT_NODE_TYPE_COUNT] = { 0 };

        dev = cspmu->dev;
        apmt_node = arm_cspmu_apmt_node(dev);
        if (!apmt_node)
                return devm_kasprintf(dev, GFP_KERNEL, PMUNAME "_%u",
                                      atomic_fetch_inc(&pmu_idx[0]));

        pmu_type = apmt_node->type;

        if (pmu_type >= ACPI_APMT_NODE_TYPE_COUNT) {
                dev_err(dev, "unsupported PMU type-%u\n", pmu_type);
                return NULL;
        }

        if (pmu_type == ACPI_APMT_NODE_TYPE_ACPI) {
                memcpy(acpi_hid_string,
                        &apmt_node->inst_primary,
                        sizeof(apmt_node->inst_primary));
                name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%s_%u", PMUNAME,
                                      arm_cspmu_type_str[pmu_type],
                                      acpi_hid_string,
                                      apmt_node->inst_secondary);
        } else {
                name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%d", PMUNAME,
                                      arm_cspmu_type_str[pmu_type],
                                      atomic_fetch_inc(&pmu_idx[pmu_type]));
        }

        return name;
}

static ssize_t arm_cspmu_cpumask_show(struct device *dev,
                                      struct device_attribute *attr,
                                      char *buf)
{
        struct pmu *pmu = dev_get_drvdata(dev);
        struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
        struct dev_ext_attribute *eattr =
                container_of(attr, struct dev_ext_attribute, attr);
        unsigned long mask_id = (unsigned long)eattr->var;
        const cpumask_t *cpumask;

        switch (mask_id) {
        case ARM_CSPMU_ACTIVE_CPU_MASK:
                cpumask = &cspmu->active_cpu;
                break;
        case ARM_CSPMU_ASSOCIATED_CPU_MASK:
                cpumask = &cspmu->associated_cpus;
                break;
        default:
                return 0;
        }
        return cpumap_print_to_pagebuf(true, buf, cpumask);
}

static struct attribute *arm_cspmu_cpumask_attrs[] = {
        ARM_CSPMU_CPUMASK_ATTR(cpumask, ARM_CSPMU_ACTIVE_CPU_MASK),
        ARM_CSPMU_CPUMASK_ATTR(associated_cpus, ARM_CSPMU_ASSOCIATED_CPU_MASK),
        NULL,
};

static struct attribute_group arm_cspmu_cpumask_attr_group = {
        .attrs = arm_cspmu_cpumask_attrs,
};

static struct arm_cspmu_impl_match impl_match[] = {
        {
                .module_name    = "nvidia_cspmu",
                .pmiidr_val     = ARM_CSPMU_IMPL_ID_NVIDIA,
                .pmiidr_mask    = PMIIDR_IMPLEMENTER,
                .module         = NULL,
                .impl_init_ops  = NULL,
        },
        {
                .module_name    = "ampere_cspmu",
                .pmiidr_val     = ARM_CSPMU_IMPL_ID_AMPERE,
                .pmiidr_mask    = PMIIDR_IMPLEMENTER,
                .module         = NULL,
                .impl_init_ops  = NULL,
        },

        {0}
};

static struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr)
{
        struct arm_cspmu_impl_match *match = impl_match;

        for (; match->pmiidr_val; match++) {
                u32 mask = match->pmiidr_mask;

                if ((match->pmiidr_val & mask) == (pmiidr & mask))
                        return match;
        }

        return NULL;
}

static u32 arm_cspmu_get_pmiidr(struct arm_cspmu *cspmu)
{
        u32 pmiidr, pmpidr;

        pmiidr = readl(cspmu->base0 + PMIIDR);

        if (pmiidr != 0)
                return pmiidr;

        /* Construct PMIIDR value from PMPIDRs. */

        pmpidr = readl(cspmu->base0 + PMPIDR0);
        pmiidr |= FIELD_PREP(PMIIDR_PRODUCTID_PART_0,
                                FIELD_GET(PMPIDR0_PART_0, pmpidr));

        pmpidr = readl(cspmu->base0 + PMPIDR1);
        pmiidr |= FIELD_PREP(PMIIDR_PRODUCTID_PART_1,
                                FIELD_GET(PMPIDR1_PART_1, pmpidr));
        pmiidr |= FIELD_PREP(PMIIDR_IMPLEMENTER_DES_0,
                                FIELD_GET(PMPIDR1_DES_0, pmpidr));

        pmpidr = readl(cspmu->base0 + PMPIDR2);
        pmiidr |= FIELD_PREP(PMIIDR_VARIANT,
                                FIELD_GET(PMPIDR2_REVISION, pmpidr));
        pmiidr |= FIELD_PREP(PMIIDR_IMPLEMENTER_DES_1,
                                FIELD_GET(PMPIDR2_DES_1, pmpidr));

        pmpidr = readl(cspmu->base0 + PMPIDR3);
        pmiidr |= FIELD_PREP(PMIIDR_REVISION,
                                FIELD_GET(PMPIDR3_REVAND, pmpidr));

        pmpidr = readl(cspmu->base0 + PMPIDR4);
        pmiidr |= FIELD_PREP(PMIIDR_IMPLEMENTER_DES_2,
                                FIELD_GET(PMPIDR4_DES_2, pmpidr));

        return pmiidr;
}

#define DEFAULT_IMPL_OP(name)   .name = arm_cspmu_##name

static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
{
        int ret = 0;
        struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(cspmu->dev);
        struct arm_cspmu_impl_match *match;

        /* Start with a default PMU implementation */
        cspmu->impl.module = THIS_MODULE;
        cspmu->impl.pmiidr = arm_cspmu_get_pmiidr(cspmu);
        cspmu->impl.ops = (struct arm_cspmu_impl_ops) {
                DEFAULT_IMPL_OP(get_event_attrs),
                DEFAULT_IMPL_OP(get_format_attrs),
                DEFAULT_IMPL_OP(get_identifier),
                DEFAULT_IMPL_OP(get_name),
                DEFAULT_IMPL_OP(is_cycle_counter_event),
                DEFAULT_IMPL_OP(event_type),
                DEFAULT_IMPL_OP(set_cc_filter),
                DEFAULT_IMPL_OP(set_ev_filter),
                DEFAULT_IMPL_OP(event_attr_is_visible),
        };

        /* Firmware may override implementer/product ID from PMIIDR */
        if (apmt_node && apmt_node->impl_id)
                cspmu->impl.pmiidr = apmt_node->impl_id;

        /* Find implementer specific attribute ops. */
        match = arm_cspmu_impl_match_get(cspmu->impl.pmiidr);

        /* Load implementer module and initialize the callbacks. */
        if (match) {
                mutex_lock(&arm_cspmu_lock);

                if (match->impl_init_ops) {
                        /* Prevent unload until PMU registration is done. */
                        if (try_module_get(match->module)) {
                                cspmu->impl.module = match->module;
                                cspmu->impl.match = match;
                                ret = match->impl_init_ops(cspmu);
                                if (ret)
                                        module_put(match->module);
                        } else {
                                WARN(1, "arm_cspmu failed to get module: %s\n",
                                        match->module_name);
                                ret = -EINVAL;
                        }
                } else {
                        request_module_nowait(match->module_name);
                        ret = -EPROBE_DEFER;
                }

                mutex_unlock(&arm_cspmu_lock);
        }

        return ret;
}

static struct attribute_group *
arm_cspmu_alloc_event_attr_group(struct arm_cspmu *cspmu)
{
        struct attribute_group *event_group;
        struct device *dev = cspmu->dev;
        const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;

        event_group =
                devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);
        if (!event_group)
                return NULL;

        event_group->name = "events";
        event_group->is_visible = impl_ops->event_attr_is_visible;
        event_group->attrs = impl_ops->get_event_attrs(cspmu);

        if (!event_group->attrs)
                return NULL;

        return event_group;
}

static struct attribute_group *
arm_cspmu_alloc_format_attr_group(struct arm_cspmu *cspmu)
{
        struct attribute_group *format_group;
        struct device *dev = cspmu->dev;

        format_group =
                devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);
        if (!format_group)
                return NULL;

        format_group->name = "format";
        format_group->attrs = cspmu->impl.ops.get_format_attrs(cspmu);

        if (!format_group->attrs)
                return NULL;

        return format_group;
}

static int arm_cspmu_alloc_attr_groups(struct arm_cspmu *cspmu)
{
        const struct attribute_group **attr_groups = cspmu->attr_groups;
        const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;

        cspmu->identifier = impl_ops->get_identifier(cspmu);
        cspmu->name = impl_ops->get_name(cspmu);

        if (!cspmu->identifier || !cspmu->name)
                return -ENOMEM;

        attr_groups[0] = arm_cspmu_alloc_event_attr_group(cspmu);
        attr_groups[1] = arm_cspmu_alloc_format_attr_group(cspmu);
        attr_groups[2] = &arm_cspmu_identifier_attr_group;
        attr_groups[3] = &arm_cspmu_cpumask_attr_group;

        if (!attr_groups[0] || !attr_groups[1])
                return -ENOMEM;

        return 0;
}

static inline void arm_cspmu_reset_counters(struct arm_cspmu *cspmu)
{
        writel(PMCR_C | PMCR_P, cspmu->base0 + PMCR);
}

static inline void arm_cspmu_start_counters(struct arm_cspmu *cspmu)
{
        writel(PMCR_E, cspmu->base0 + PMCR);
}

static inline void arm_cspmu_stop_counters(struct arm_cspmu *cspmu)
{
        writel(0, cspmu->base0 + PMCR);
}

static void arm_cspmu_enable(struct pmu *pmu)
{
        bool disabled;
        struct arm_cspmu *cspmu = to_arm_cspmu(pmu);

        disabled = bitmap_empty(cspmu->hw_events.used_ctrs,
                                cspmu->num_logical_ctrs);

        if (disabled)
                return;

        arm_cspmu_start_counters(cspmu);
}

static void arm_cspmu_disable(struct pmu *pmu)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(pmu);

        arm_cspmu_stop_counters(cspmu);
}

static int arm_cspmu_get_event_idx(struct arm_cspmu_hw_events *hw_events,
                                struct perf_event *event)
{
        int idx, ret;
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);

        if (supports_cycle_counter(cspmu)) {
                if (cspmu->impl.ops.is_cycle_counter_event(event)) {
                        /* Search for available cycle counter. */
                        if (test_and_set_bit(cspmu->cycle_counter_logical_idx,
                                             hw_events->used_ctrs))
                                return -EAGAIN;

                        return cspmu->cycle_counter_logical_idx;
                }

                /*
                 * Search a regular counter from the used counter bitmap.
                 * The cycle counter divides the bitmap into two parts. Search
                 * the first then second half to exclude the cycle counter bit.
                 */
                idx = find_first_zero_bit(hw_events->used_ctrs,
                                          cspmu->cycle_counter_logical_idx);
                if (idx >= cspmu->cycle_counter_logical_idx) {
                        idx = find_next_zero_bit(
                                hw_events->used_ctrs,
                                cspmu->num_logical_ctrs,
                                cspmu->cycle_counter_logical_idx + 1);
                }
        } else {
                idx = find_first_zero_bit(hw_events->used_ctrs,
                                          cspmu->num_logical_ctrs);
        }

        if (idx >= cspmu->num_logical_ctrs)
                return -EAGAIN;

        if (cspmu->impl.ops.validate_event) {
                ret = cspmu->impl.ops.validate_event(cspmu, event);
                if (ret)
                        return ret;
        }

        set_bit(idx, hw_events->used_ctrs);

        return idx;
}

static bool arm_cspmu_validate_event(struct pmu *pmu,
                                 struct arm_cspmu_hw_events *hw_events,
                                 struct perf_event *event)
{
        if (is_software_event(event))
                return true;

        /* Reject groups spanning multiple HW PMUs. */
        if (event->pmu != pmu)
                return false;

        return (arm_cspmu_get_event_idx(hw_events, event) >= 0);
}

/*
 * Make sure the group of events can be scheduled at once
 * on the PMU.
 */
static bool arm_cspmu_validate_group(struct perf_event *event)
{
        struct perf_event *sibling, *leader = event->group_leader;
        struct arm_cspmu_hw_events fake_hw_events;

        if (event->group_leader == event)
                return true;

        memset(&fake_hw_events, 0, sizeof(fake_hw_events));

        if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events, leader))
                return false;

        for_each_sibling_event(sibling, leader) {
                if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events,
                                                  sibling))
                        return false;
        }

        return arm_cspmu_validate_event(event->pmu, &fake_hw_events, event);
}

static int arm_cspmu_event_init(struct perf_event *event)
{
        struct arm_cspmu *cspmu;
        struct hw_perf_event *hwc = &event->hw;

        cspmu = to_arm_cspmu(event->pmu);

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

        /*
         * Following other "uncore" PMUs, we do not support sampling mode or
         * attach to a task (per-process mode).
         */
        if (is_sampling_event(event)) {
                dev_dbg(cspmu->pmu.dev,
                        "Can't support sampling events\n");
                return -EOPNOTSUPP;
        }

        if (event->cpu < 0 || event->attach_state & PERF_ATTACH_TASK) {
                dev_dbg(cspmu->pmu.dev,
                        "Can't support per-task counters\n");
                return -EINVAL;
        }

        /*
         * Make sure the CPU assignment is on one of the CPUs associated with
         * this PMU.
         */
        if (!cpumask_test_cpu(event->cpu, &cspmu->associated_cpus)) {
                dev_dbg(cspmu->pmu.dev,
                        "Requested cpu is not associated with the PMU\n");
                return -EINVAL;
        }

        /* Enforce the current active CPU to handle the events in this PMU. */
        event->cpu = cpumask_first(&cspmu->active_cpu);
        if (event->cpu >= nr_cpu_ids)
                return -EINVAL;

        if (!arm_cspmu_validate_group(event))
                return -EINVAL;

        /*
         * The logical counter id is tracked with hw_perf_event.extra_reg.idx.
         * The physical counter id is tracked with hw_perf_event.idx.
         * We don't assign an index until we actually place the event onto
         * hardware. Use -1 to signify that we haven't decided where to put it
         * yet.
         */
        hwc->idx = -1;
        hwc->extra_reg.idx = -1;
        hwc->config = cspmu->impl.ops.event_type(event);

        return 0;
}

static inline u32 counter_offset(u32 reg_sz, u32 ctr_idx)
{
        return (PMEVCNTR_LO + (reg_sz * ctr_idx));
}

static void arm_cspmu_write_counter(struct perf_event *event, u64 val)
{
        u32 offset;
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);

        if (use_64b_counter_reg(cspmu)) {
                offset = counter_offset(sizeof(u64), event->hw.idx);

                if (cspmu->has_atomic_dword)
                        writeq(val, cspmu->base1 + offset);
                else
                        lo_hi_writeq(val, cspmu->base1 + offset);
        } else {
                offset = counter_offset(sizeof(u32), event->hw.idx);

                writel(lower_32_bits(val), cspmu->base1 + offset);
        }
}

static u64 arm_cspmu_read_counter(struct perf_event *event)
{
        u32 offset;
        const void __iomem *counter_addr;
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);

        if (use_64b_counter_reg(cspmu)) {
                offset = counter_offset(sizeof(u64), event->hw.idx);
                counter_addr = cspmu->base1 + offset;

                return cspmu->has_atomic_dword ?
                               readq(counter_addr) :
                               read_reg64_hilohi(counter_addr, HILOHI_MAX_POLL);
        }

        offset = counter_offset(sizeof(u32), event->hw.idx);
        return readl(cspmu->base1 + offset);
}

/*
 * arm_cspmu_set_event_period: Set the period for the counter.
 *
 * To handle cases of extreme interrupt latency, we program
 * the counter with half of the max count for the counters.
 */
static void arm_cspmu_set_event_period(struct perf_event *event)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
        u64 val = counter_mask(cspmu) >> 1ULL;

        local64_set(&event->hw.prev_count, val);
        arm_cspmu_write_counter(event, val);
}

static void arm_cspmu_enable_counter(struct arm_cspmu *cspmu, int idx)
{
        u32 reg_id, reg_bit, inten_off, cnten_off;

        reg_id = COUNTER_TO_SET_CLR_ID(idx);
        reg_bit = COUNTER_TO_SET_CLR_BIT(idx);

        inten_off = PMINTENSET + (4 * reg_id);
        cnten_off = PMCNTENSET + (4 * reg_id);

        writel(BIT(reg_bit), cspmu->base0 + inten_off);
        writel(BIT(reg_bit), cspmu->base0 + cnten_off);
}

static void arm_cspmu_disable_counter(struct arm_cspmu *cspmu, int idx)
{
        u32 reg_id, reg_bit, inten_off, cnten_off;

        reg_id = COUNTER_TO_SET_CLR_ID(idx);
        reg_bit = COUNTER_TO_SET_CLR_BIT(idx);

        inten_off = PMINTENCLR + (4 * reg_id);
        cnten_off = PMCNTENCLR + (4 * reg_id);

        writel(BIT(reg_bit), cspmu->base0 + cnten_off);
        writel(BIT(reg_bit), cspmu->base0 + inten_off);
}

static void arm_cspmu_event_update(struct perf_event *event)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        u64 delta, prev, now;

        do {
                prev = local64_read(&hwc->prev_count);
                now = arm_cspmu_read_counter(event);
        } while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev);

        delta = (now - prev) & counter_mask(cspmu);
        local64_add(delta, &event->count);
}

static inline void arm_cspmu_set_event(struct arm_cspmu *cspmu,
                                        struct hw_perf_event *hwc)
{
        u32 offset = PMEVTYPER + (4 * hwc->idx);

        writel(hwc->config, cspmu->base0 + offset);
}

static void arm_cspmu_set_ev_filter(struct arm_cspmu *cspmu,
                                    const struct perf_event *event)
{
        u32 filter = event->attr.config1 & ARM_CSPMU_FILTER_MASK;
        u32 filter2 = event->attr.config2 & ARM_CSPMU_FILTER_MASK;
        u32 offset = 4 * event->hw.idx;

        writel(filter, cspmu->base0 + PMEVFILTR + offset);
        writel(filter2, cspmu->base0 + PMEVFILT2R + offset);
}

static void arm_cspmu_set_cc_filter(struct arm_cspmu *cspmu,
                                    const struct perf_event *event)
{
        u32 filter = event->attr.config1 & ARM_CSPMU_FILTER_MASK;

        writel(filter, cspmu->base0 + PMCCFILTR);
}

static void arm_cspmu_start(struct perf_event *event, int pmu_flags)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;

        /* We always reprogram the counter */
        if (pmu_flags & PERF_EF_RELOAD)
                WARN_ON(!(hwc->state & PERF_HES_UPTODATE));

        arm_cspmu_set_event_period(event);

        if (event->hw.extra_reg.idx == cspmu->cycle_counter_logical_idx) {
                cspmu->impl.ops.set_cc_filter(cspmu, event);
        } else {
                arm_cspmu_set_event(cspmu, hwc);
                cspmu->impl.ops.set_ev_filter(cspmu, event);
        }

        hwc->state = 0;

        arm_cspmu_enable_counter(cspmu, hwc->idx);
}

static void arm_cspmu_stop(struct perf_event *event, int pmu_flags)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;

        if (hwc->state & PERF_HES_STOPPED)
                return;

        arm_cspmu_disable_counter(cspmu, hwc->idx);

        if (cspmu->impl.ops.reset_ev_filter)
                cspmu->impl.ops.reset_ev_filter(cspmu, event);

        arm_cspmu_event_update(event);

        hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
}

static inline u32 to_phys_idx(struct arm_cspmu *cspmu, u32 idx)
{
        return (idx == cspmu->cycle_counter_logical_idx) ?
                ARM_CSPMU_CYCLE_CNTR_IDX : idx;
}

static int arm_cspmu_add(struct perf_event *event, int flags)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
        struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;
        struct hw_perf_event *hwc = &event->hw;
        int idx;

        if (WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(),
                                           &cspmu->associated_cpus)))
                return -ENOENT;

        idx = arm_cspmu_get_event_idx(hw_events, event);
        if (idx < 0)
                return idx;

        hw_events->events[idx] = event;
        hwc->idx = to_phys_idx(cspmu, idx);
        hwc->extra_reg.idx = idx;
        hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;

        if (flags & PERF_EF_START)
                arm_cspmu_start(event, PERF_EF_RELOAD);

        /* Propagate changes to the userspace mapping. */
        perf_event_update_userpage(event);

        return 0;
}

static void arm_cspmu_del(struct perf_event *event, int flags)
{
        struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
        struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;
        struct hw_perf_event *hwc = &event->hw;
        int idx = hwc->extra_reg.idx;

        arm_cspmu_stop(event, PERF_EF_UPDATE);

        hw_events->events[idx] = NULL;

        clear_bit(idx, hw_events->used_ctrs);

        perf_event_update_userpage(event);
}

static void arm_cspmu_read(struct perf_event *event)
{
        arm_cspmu_event_update(event);
}

static struct arm_cspmu *arm_cspmu_alloc(struct platform_device *pdev)
{
        struct acpi_apmt_node *apmt_node;
        struct arm_cspmu *cspmu;
        struct device *dev = &pdev->dev;

        cspmu = devm_kzalloc(dev, sizeof(*cspmu), GFP_KERNEL);
        if (!cspmu)
                return NULL;

        cspmu->dev = dev;
        platform_set_drvdata(pdev, cspmu);

        apmt_node = arm_cspmu_apmt_node(dev);
        if (apmt_node) {
                cspmu->has_atomic_dword = apmt_node->flags & ACPI_APMT_FLAGS_ATOMIC;
        } else {
                u32 width = 0;

                device_property_read_u32(dev, "reg-io-width", &width);
                cspmu->has_atomic_dword = (width == 8);
        }

        return cspmu;
}

static int arm_cspmu_init_mmio(struct arm_cspmu *cspmu)
{
        struct device *dev;
        struct platform_device *pdev;

        dev = cspmu->dev;
        pdev = to_platform_device(dev);

        /* Base address for page 0. */
        cspmu->base0 = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(cspmu->base0)) {
                dev_err(dev, "ioremap failed for page-0 resource\n");
                return PTR_ERR(cspmu->base0);
        }

        /* Base address for page 1 if supported. Otherwise point to page 0. */
        cspmu->base1 = cspmu->base0;
        if (platform_get_resource(pdev, IORESOURCE_MEM, 1)) {
                cspmu->base1 = devm_platform_ioremap_resource(pdev, 1);
                if (IS_ERR(cspmu->base1)) {
                        dev_err(dev, "ioremap failed for page-1 resource\n");
                        return PTR_ERR(cspmu->base1);
                }
        }

        cspmu->pmcfgr = readl(cspmu->base0 + PMCFGR);

        cspmu->num_logical_ctrs = FIELD_GET(PMCFGR_N, cspmu->pmcfgr) + 1;

        cspmu->cycle_counter_logical_idx = ARM_CSPMU_MAX_HW_CNTRS;

        if (supports_cycle_counter(cspmu)) {
                /*
                 * The last logical counter is mapped to cycle counter if
                 * there is a gap between regular and cycle counter. Otherwise,
                 * logical and physical have 1-to-1 mapping.
                 */
                cspmu->cycle_counter_logical_idx =
                        (cspmu->num_logical_ctrs <= ARM_CSPMU_CYCLE_CNTR_IDX) ?
                                cspmu->num_logical_ctrs - 1 :
                                ARM_CSPMU_CYCLE_CNTR_IDX;
        }

        cspmu->num_set_clr_reg =
                DIV_ROUND_UP(cspmu->num_logical_ctrs,
                                ARM_CSPMU_SET_CLR_COUNTER_NUM);

        cspmu->hw_events.events =
                devm_kcalloc(dev, cspmu->num_logical_ctrs,
                             sizeof(*cspmu->hw_events.events), GFP_KERNEL);

        if (!cspmu->hw_events.events)
                return -ENOMEM;

        return 0;
}

static inline int arm_cspmu_get_reset_overflow(struct arm_cspmu *cspmu,
                                               u32 *pmovs)
{
        int i;
        u32 pmovclr_offset = PMOVSCLR;
        u32 has_overflowed = 0;

        for (i = 0; i < cspmu->num_set_clr_reg; ++i) {
                pmovs[i] = readl(cspmu->base1 + pmovclr_offset);
                has_overflowed |= pmovs[i];
                writel(pmovs[i], cspmu->base1 + pmovclr_offset);
                pmovclr_offset += sizeof(u32);
        }

        return has_overflowed != 0;
}

static irqreturn_t arm_cspmu_handle_irq(int irq_num, void *dev)
{
        int idx, has_overflowed;
        struct perf_event *event;
        struct arm_cspmu *cspmu = dev;
        DECLARE_BITMAP(pmovs, ARM_CSPMU_MAX_HW_CNTRS);
        bool handled = false;

        arm_cspmu_stop_counters(cspmu);

        has_overflowed = arm_cspmu_get_reset_overflow(cspmu, (u32 *)pmovs);
        if (!has_overflowed)
                goto done;

        for_each_set_bit(idx, cspmu->hw_events.used_ctrs,
                        cspmu->num_logical_ctrs) {
                event = cspmu->hw_events.events[idx];

                if (!event)
                        continue;

                if (!test_bit(event->hw.idx, pmovs))
                        continue;

                arm_cspmu_event_update(event);
                arm_cspmu_set_event_period(event);

                handled = true;
        }

done:
        arm_cspmu_start_counters(cspmu);
        return IRQ_RETVAL(handled);
}

static int arm_cspmu_request_irq(struct arm_cspmu *cspmu)
{
        int irq, ret;
        struct device *dev;
        struct platform_device *pdev;

        dev = cspmu->dev;
        pdev = to_platform_device(dev);

        /* Skip IRQ request if the PMU does not support overflow interrupt. */
        irq = platform_get_irq_optional(pdev, 0);
        if (irq < 0)
                return irq == -ENXIO ? 0 : irq;

        ret = devm_request_irq(dev, irq, arm_cspmu_handle_irq,
                               IRQF_NOBALANCING | IRQF_NO_THREAD, dev_name(dev),
                               cspmu);
        if (ret) {
                dev_err(dev, "Could not request IRQ %d\n", irq);
                return ret;
        }

        cspmu->irq = irq;

        return 0;
}

#if defined(CONFIG_ACPI) && defined(CONFIG_ARM64)
#include <acpi/processor.h>

static inline int arm_cspmu_find_cpu_container(int cpu, u32 container_uid)
{
        struct device *cpu_dev;
        struct acpi_device *acpi_dev;

        cpu_dev = get_cpu_device(cpu);
        if (!cpu_dev)
                return -ENODEV;

        acpi_dev = ACPI_COMPANION(cpu_dev);
        while (acpi_dev) {
                if (acpi_dev_hid_uid_match(acpi_dev, ACPI_PROCESSOR_CONTAINER_HID, container_uid))
                        return 0;

                acpi_dev = acpi_dev_parent(acpi_dev);
        }

        return -ENODEV;
}

static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)
{
        struct acpi_apmt_node *apmt_node;
        int affinity_flag;
        int cpu;

        apmt_node = arm_cspmu_apmt_node(cspmu->dev);
        affinity_flag = apmt_node->flags & ACPI_APMT_FLAGS_AFFINITY;

        if (affinity_flag == ACPI_APMT_FLAGS_AFFINITY_PROC) {
                for_each_possible_cpu(cpu) {
                        if (apmt_node->proc_affinity ==
                            get_acpi_id_for_cpu(cpu)) {
                                cpumask_set_cpu(cpu, &cspmu->associated_cpus);
                                break;
                        }
                }
        } else {
                for_each_possible_cpu(cpu) {
                        if (arm_cspmu_find_cpu_container(
                                    cpu, apmt_node->proc_affinity))
                                continue;

                        cpumask_set_cpu(cpu, &cspmu->associated_cpus);
                }
        }

        return 0;
}
#else
static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)
{
        return -ENODEV;
}
#endif

static int arm_cspmu_of_get_cpus(struct arm_cspmu *cspmu)
{
        struct of_phandle_iterator it;
        int ret, cpu;

        of_for_each_phandle(&it, ret, dev_of_node(cspmu->dev), "cpus", NULL, 0) {
                cpu = of_cpu_node_to_id(it.node);
                if (cpu < 0)
                        continue;
                cpumask_set_cpu(cpu, &cspmu->associated_cpus);
        }
        return ret == -ENOENT ? 0 : ret;
}

static int arm_cspmu_get_cpus(struct arm_cspmu *cspmu)
{
        int ret = 0;

        if (arm_cspmu_apmt_node(cspmu->dev))
                ret = arm_cspmu_acpi_get_cpus(cspmu);
        else if (device_property_present(cspmu->dev, "cpus"))
                ret = arm_cspmu_of_get_cpus(cspmu);
        else
                cpumask_copy(&cspmu->associated_cpus, cpu_possible_mask);

        if (!ret && cpumask_empty(&cspmu->associated_cpus)) {
                dev_dbg(cspmu->dev, "No cpu associated with the PMU\n");
                ret = -ENODEV;
        }
        return ret;
}

static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
{
        int ret, capabilities;

        ret = arm_cspmu_alloc_attr_groups(cspmu);
        if (ret)
                return ret;

        ret = cpuhp_state_add_instance(arm_cspmu_cpuhp_state,
                                       &cspmu->cpuhp_node);
        if (ret)
                return ret;

        capabilities = PERF_PMU_CAP_NO_EXCLUDE;
        if (cspmu->irq == 0)
                capabilities |= PERF_PMU_CAP_NO_INTERRUPT;

        cspmu->pmu = (struct pmu){
                .task_ctx_nr    = perf_invalid_context,
                .module         = cspmu->impl.module,
                .parent         = cspmu->dev,
                .pmu_enable     = arm_cspmu_enable,
                .pmu_disable    = arm_cspmu_disable,
                .event_init     = arm_cspmu_event_init,
                .add            = arm_cspmu_add,
                .del            = arm_cspmu_del,
                .start          = arm_cspmu_start,
                .stop           = arm_cspmu_stop,
                .read           = arm_cspmu_read,
                .attr_groups    = cspmu->attr_groups,
                .capabilities   = capabilities,
        };

        /* Hardware counter init */
        arm_cspmu_reset_counters(cspmu);

        ret = perf_pmu_register(&cspmu->pmu, cspmu->name, -1);
        if (ret) {
                cpuhp_state_remove_instance(arm_cspmu_cpuhp_state,
                                            &cspmu->cpuhp_node);
        }

        return ret;
}

static int arm_cspmu_device_probe(struct platform_device *pdev)
{
        int ret;
        struct arm_cspmu *cspmu;

        cspmu = arm_cspmu_alloc(pdev);
        if (!cspmu)
                return -ENOMEM;

        ret = arm_cspmu_init_mmio(cspmu);
        if (ret)
                return ret;

        ret = arm_cspmu_request_irq(cspmu);
        if (ret)
                return ret;

        ret = arm_cspmu_get_cpus(cspmu);
        if (ret)
                return ret;

        ret = arm_cspmu_init_impl_ops(cspmu);
        if (ret)
                return ret;

        ret = arm_cspmu_register_pmu(cspmu);

        /* Matches arm_cspmu_init_impl_ops() above. */
        if (cspmu->impl.module != THIS_MODULE)
                module_put(cspmu->impl.module);

        return ret;
}

static void arm_cspmu_device_remove(struct platform_device *pdev)
{
        struct arm_cspmu *cspmu = platform_get_drvdata(pdev);

        perf_pmu_unregister(&cspmu->pmu);
        cpuhp_state_remove_instance(arm_cspmu_cpuhp_state, &cspmu->cpuhp_node);
}

static const struct platform_device_id arm_cspmu_id[] = {
        {DRVNAME, 0},
        { },
};
MODULE_DEVICE_TABLE(platform, arm_cspmu_id);

static const struct of_device_id arm_cspmu_of_match[] = {
        { .compatible = "arm,coresight-pmu" },
        {}
};
MODULE_DEVICE_TABLE(of, arm_cspmu_of_match);

static struct platform_driver arm_cspmu_driver = {
        .driver = {
                .name = DRVNAME,
                .of_match_table = arm_cspmu_of_match,
                .suppress_bind_attrs = true,
        },
        .probe = arm_cspmu_device_probe,
        .remove = arm_cspmu_device_remove,
        .id_table = arm_cspmu_id,
};

static void arm_cspmu_set_active_cpu(int cpu, struct arm_cspmu *cspmu)
{
        cpumask_set_cpu(cpu, &cspmu->active_cpu);
        if (cspmu->irq)
                WARN_ON(irq_set_affinity(cspmu->irq, &cspmu->active_cpu));
}

static int arm_cspmu_cpu_online(unsigned int cpu, struct hlist_node *node)
{
        struct arm_cspmu *cspmu =
                hlist_entry_safe(node, struct arm_cspmu, cpuhp_node);

        if (!cpumask_test_cpu(cpu, &cspmu->associated_cpus))
                return 0;

        /* If the PMU is already managed, there is nothing to do */
        if (!cpumask_empty(&cspmu->active_cpu))
                return 0;

        /* Use this CPU for event counting */
        arm_cspmu_set_active_cpu(cpu, cspmu);

        return 0;
}

static int arm_cspmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
{
        unsigned int dst;

        struct arm_cspmu *cspmu =
                hlist_entry_safe(node, struct arm_cspmu, cpuhp_node);

        /* Nothing to do if this CPU doesn't own the PMU */
        if (!cpumask_test_and_clear_cpu(cpu, &cspmu->active_cpu))
                return 0;

        /* Choose a new CPU to migrate ownership of the PMU to */
        dst = cpumask_any_and_but(&cspmu->associated_cpus,
                                  cpu_online_mask, cpu);
        if (dst >= nr_cpu_ids)
                return 0;

        /* Use this CPU for event counting */
        perf_pmu_migrate_context(&cspmu->pmu, cpu, dst);
        arm_cspmu_set_active_cpu(dst, cspmu);

        return 0;
}

static int __init arm_cspmu_init(void)
{
        int ret;

        ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
                                        "perf/arm/cspmu:online",
                                        arm_cspmu_cpu_online,
                                        arm_cspmu_cpu_teardown);
        if (ret < 0)
                return ret;
        arm_cspmu_cpuhp_state = ret;
        return platform_driver_register(&arm_cspmu_driver);
}

static void __exit arm_cspmu_exit(void)
{
        platform_driver_unregister(&arm_cspmu_driver);
        cpuhp_remove_multi_state(arm_cspmu_cpuhp_state);
}

int arm_cspmu_impl_register(const struct arm_cspmu_impl_match *impl_match)
{
        struct arm_cspmu_impl_match *match;
        int ret = 0;

        match = arm_cspmu_impl_match_get(impl_match->pmiidr_val);

        if (match) {
                mutex_lock(&arm_cspmu_lock);

                if (!match->impl_init_ops) {
                        match->module = impl_match->module;
                        match->impl_init_ops = impl_match->impl_init_ops;
                } else {
                        /* Broken match table may contain non-unique entries */
                        WARN(1, "arm_cspmu backend already registered for module: %s, pmiidr: 0x%x, mask: 0x%x\n",
                                match->module_name,
                                match->pmiidr_val,
                                match->pmiidr_mask);

                        ret = -EINVAL;
                }

                mutex_unlock(&arm_cspmu_lock);

                if (!ret)
                        ret = driver_attach(&arm_cspmu_driver.driver);
        } else {
                pr_err("arm_cspmu reg failed, unable to find a match for pmiidr: 0x%x\n",
                        impl_match->pmiidr_val);

                ret = -EINVAL;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(arm_cspmu_impl_register);

static int arm_cspmu_match_device(struct device *dev, const void *match)
{
        struct arm_cspmu *cspmu = platform_get_drvdata(to_platform_device(dev));

        return (cspmu && cspmu->impl.match == match) ? 1 : 0;
}

void arm_cspmu_impl_unregister(const struct arm_cspmu_impl_match *impl_match)
{
        struct device *dev;
        struct arm_cspmu_impl_match *match;

        match = arm_cspmu_impl_match_get(impl_match->pmiidr_val);

        if (WARN_ON(!match))
                return;

        /* Unbind the driver from all matching backend devices. */
        while ((dev = driver_find_device(&arm_cspmu_driver.driver, NULL,
                        match, arm_cspmu_match_device))) {
                device_release_driver(dev);
                put_device(dev);
        }

        mutex_lock(&arm_cspmu_lock);

        match->module = NULL;
        match->impl_init_ops = NULL;

        mutex_unlock(&arm_cspmu_lock);
}
EXPORT_SYMBOL_GPL(arm_cspmu_impl_unregister);

module_init(arm_cspmu_init);
module_exit(arm_cspmu_exit);

MODULE_DESCRIPTION("ARM CoreSight Architecture Performance Monitor Driver");
MODULE_LICENSE("GPL v2");