/*
 * Copyright (C) 2013 Advanced Micro Devices, Inc.
 *
 * Author: Jacob Shin <jacob.shin@amd.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/perf_event.h>
#include <linux/percpu.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>

#include <asm/cpufeature.h>
#include <asm/perf_event.h>
#include <asm/msr.h>
#include <asm/smp.h>

#define NUM_COUNTERS_NB         4
#define NUM_COUNTERS_L2         4
#define NUM_COUNTERS_L3         6
#define MAX_COUNTERS            6

#define RDPMC_BASE_NB           6
#define RDPMC_BASE_LLC          10

#define COUNTER_SHIFT           16

#undef pr_fmt
#define pr_fmt(fmt)     "amd_uncore: " fmt

static int num_counters_llc;
static int num_counters_nb;
static bool l3_mask;

static HLIST_HEAD(uncore_unused_list);

struct amd_uncore {
        int id;
        int refcnt;
        int cpu;
        int num_counters;
        int rdpmc_base;
        u32 msr_base;
        cpumask_t *active_mask;
        struct pmu *pmu;
        struct perf_event *events[MAX_COUNTERS];
        struct hlist_node node;
};

static struct amd_uncore * __percpu *amd_uncore_nb;
static struct amd_uncore * __percpu *amd_uncore_llc;

static struct pmu amd_nb_pmu;
static struct pmu amd_llc_pmu;

static cpumask_t amd_nb_active_mask;
static cpumask_t amd_llc_active_mask;

static bool is_nb_event(struct perf_event *event)
{
        return event->pmu->type == amd_nb_pmu.type;
}

static bool is_llc_event(struct perf_event *event)
{
        return event->pmu->type == amd_llc_pmu.type;
}

static struct amd_uncore *event_to_amd_uncore(struct perf_event *event)
{
        if (is_nb_event(event) && amd_uncore_nb)
                return *per_cpu_ptr(amd_uncore_nb, event->cpu);
        else if (is_llc_event(event) && amd_uncore_llc)
                return *per_cpu_ptr(amd_uncore_llc, event->cpu);

        return NULL;
}

static void amd_uncore_read(struct perf_event *event)
{
        struct hw_perf_event *hwc = &event->hw;
        u64 prev, new;
        s64 delta;

        /*
         * since we do not enable counter overflow interrupts,
         * we do not have to worry about prev_count changing on us
         */

        prev = local64_read(&hwc->prev_count);
        rdpmcl(hwc->event_base_rdpmc, new);
        local64_set(&hwc->prev_count, new);
        delta = (new << COUNTER_SHIFT) - (prev << COUNTER_SHIFT);
        delta >>= COUNTER_SHIFT;
        local64_add(delta, &event->count);
}

static void amd_uncore_start(struct perf_event *event, int flags)
{
        struct hw_perf_event *hwc = &event->hw;

        if (flags & PERF_EF_RELOAD)
                wrmsrl(hwc->event_base, (u64)local64_read(&hwc->prev_count));

        hwc->state = 0;
        wrmsrl(hwc->config_base, (hwc->config | ARCH_PERFMON_EVENTSEL_ENABLE));
        perf_event_update_userpage(event);
}

static void amd_uncore_stop(struct perf_event *event, int flags)
{
        struct hw_perf_event *hwc = &event->hw;

        wrmsrl(hwc->config_base, hwc->config);
        hwc->state |= PERF_HES_STOPPED;

        if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
                amd_uncore_read(event);
                hwc->state |= PERF_HES_UPTODATE;
        }
}

static int amd_uncore_add(struct perf_event *event, int flags)
{
        int i;
        struct amd_uncore *uncore = event_to_amd_uncore(event);
        struct hw_perf_event *hwc = &event->hw;

        /* are we already assigned? */
        if (hwc->idx != -1 && uncore->events[hwc->idx] == event)
                goto out;

        for (i = 0; i < uncore->num_counters; i++) {
                if (uncore->events[i] == event) {
                        hwc->idx = i;
                        goto out;
                }
        }

        /* if not, take the first available counter */
        hwc->idx = -1;
        for (i = 0; i < uncore->num_counters; i++) {
                if (cmpxchg(&uncore->events[i], NULL, event) == NULL) {
                        hwc->idx = i;
                        break;
                }
        }

out:
        if (hwc->idx == -1)
                return -EBUSY;

        hwc->config_base = uncore->msr_base + (2 * hwc->idx);
        hwc->event_base = uncore->msr_base + 1 + (2 * hwc->idx);
        hwc->event_base_rdpmc = uncore->rdpmc_base + hwc->idx;
        hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;

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

        return 0;
}

static void amd_uncore_del(struct perf_event *event, int flags)
{
        int i;
        struct amd_uncore *uncore = event_to_amd_uncore(event);
        struct hw_perf_event *hwc = &event->hw;

        amd_uncore_stop(event, PERF_EF_UPDATE);

        for (i = 0; i < uncore->num_counters; i++) {
                if (cmpxchg(&uncore->events[i], event, NULL) == event)
                        break;
        }

        hwc->idx = -1;
}

static int amd_uncore_event_init(struct perf_event *event)
{
        struct amd_uncore *uncore;
        struct hw_perf_event *hwc = &event->hw;

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

        /*
         * NB and Last level cache counters (MSRs) are shared across all cores
         * that share the same NB / Last level cache. Interrupts can be directed
         * to a single target core, however, event counts generated by processes
         * running on other cores cannot be masked out. So we do not support
         * sampling and per-thread events.
         */
        if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
                return -EINVAL;

        /* and we do not enable counter overflow interrupts */
        hwc->config = event->attr.config & AMD64_RAW_EVENT_MASK_NB;
        hwc->idx = -1;

        /*
         * SliceMask and ThreadMask need to be set for certain L3 events in
         * Family 17h. For other events, the two fields do not affect the count.
         */
        if (l3_mask)
                hwc->config |= (AMD64_L3_SLICE_MASK | AMD64_L3_THREAD_MASK);

        if (event->cpu < 0)
                return -EINVAL;

        uncore = event_to_amd_uncore(event);
        if (!uncore)
                return -ENODEV;

        /*
         * since request can come in to any of the shared cores, we will remap
         * to a single common cpu.
         */
        event->cpu = uncore->cpu;

        return 0;
}

static ssize_t amd_uncore_attr_show_cpumask(struct device *dev,
                                            struct device_attribute *attr,
                                            char *buf)
{
        cpumask_t *active_mask;
        struct pmu *pmu = dev_get_drvdata(dev);

        if (pmu->type == amd_nb_pmu.type)
                active_mask = &amd_nb_active_mask;
        else if (pmu->type == amd_llc_pmu.type)
                active_mask = &amd_llc_active_mask;
        else
                return 0;

        return cpumap_print_to_pagebuf(true, buf, active_mask);
}
static DEVICE_ATTR(cpumask, S_IRUGO, amd_uncore_attr_show_cpumask, NULL);

static struct attribute *amd_uncore_attrs[] = {
        &dev_attr_cpumask.attr,
        NULL,
};

static struct attribute_group amd_uncore_attr_group = {
        .attrs = amd_uncore_attrs,
};

/*
 * Similar to PMU_FORMAT_ATTR but allowing for format_attr to be assigned based
 * on family
 */
#define AMD_FORMAT_ATTR(_dev, _name, _format)                                \
static ssize_t                                                               \
_dev##_show##_name(struct device *dev,                                       \
                struct device_attribute *attr,                               \
                char *page)                                                  \
{                                                                            \
        BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);                          \
        return sprintf(page, _format "\n");                                  \
}                                                                            \
static struct device_attribute format_attr_##_dev##_name = __ATTR_RO(_dev);

/* Used for each uncore counter type */
#define AMD_ATTRIBUTE(_name)                                                 \
static struct attribute *amd_uncore_format_attr_##_name[] = {                \
        &format_attr_event_##_name.attr,                                     \
        &format_attr_umask.attr,                                             \
        NULL,                                                                \
};                                                                           \
static struct attribute_group amd_uncore_format_group_##_name = {            \
        .name = "format",                                                    \
        .attrs = amd_uncore_format_attr_##_name,                             \
};                                                                           \
static const struct attribute_group *amd_uncore_attr_groups_##_name[] = {    \
        &amd_uncore_attr_group,                                              \
        &amd_uncore_format_group_##_name,                                    \
        NULL,                                                                \
};

AMD_FORMAT_ATTR(event, , "config:0-7,32-35");
AMD_FORMAT_ATTR(umask, , "config:8-15");
AMD_FORMAT_ATTR(event, _df, "config:0-7,32-35,59-60");
AMD_FORMAT_ATTR(event, _l3, "config:0-7");
AMD_ATTRIBUTE(df);
AMD_ATTRIBUTE(l3);

static struct pmu amd_nb_pmu = {
        .task_ctx_nr    = perf_invalid_context,
        .event_init     = amd_uncore_event_init,
        .add            = amd_uncore_add,
        .del            = amd_uncore_del,
        .start          = amd_uncore_start,
        .stop           = amd_uncore_stop,
        .read           = amd_uncore_read,
        .capabilities   = PERF_PMU_CAP_NO_EXCLUDE,
};

static struct pmu amd_llc_pmu = {
        .task_ctx_nr    = perf_invalid_context,
        .event_init     = amd_uncore_event_init,
        .add            = amd_uncore_add,
        .del            = amd_uncore_del,
        .start          = amd_uncore_start,
        .stop           = amd_uncore_stop,
        .read           = amd_uncore_read,
        .capabilities   = PERF_PMU_CAP_NO_EXCLUDE,
};

static struct amd_uncore *amd_uncore_alloc(unsigned int cpu)
{
        return kzalloc_node(sizeof(struct amd_uncore), GFP_KERNEL,
                        cpu_to_node(cpu));
}

static int amd_uncore_cpu_up_prepare(unsigned int cpu)
{
        struct amd_uncore *uncore_nb = NULL, *uncore_llc;

        if (amd_uncore_nb) {
                uncore_nb = amd_uncore_alloc(cpu);
                if (!uncore_nb)
                        goto fail;
                uncore_nb->cpu = cpu;
                uncore_nb->num_counters = num_counters_nb;
                uncore_nb->rdpmc_base = RDPMC_BASE_NB;
                uncore_nb->msr_base = MSR_F15H_NB_PERF_CTL;
                uncore_nb->active_mask = &amd_nb_active_mask;
                uncore_nb->pmu = &amd_nb_pmu;
                uncore_nb->id = -1;
                *per_cpu_ptr(amd_uncore_nb, cpu) = uncore_nb;
        }

        if (amd_uncore_llc) {
                uncore_llc = amd_uncore_alloc(cpu);
                if (!uncore_llc)
                        goto fail;
                uncore_llc->cpu = cpu;
                uncore_llc->num_counters = num_counters_llc;
                uncore_llc->rdpmc_base = RDPMC_BASE_LLC;
                uncore_llc->msr_base = MSR_F16H_L2I_PERF_CTL;
                uncore_llc->active_mask = &amd_llc_active_mask;
                uncore_llc->pmu = &amd_llc_pmu;
                uncore_llc->id = -1;
                *per_cpu_ptr(amd_uncore_llc, cpu) = uncore_llc;
        }

        return 0;

fail:
        if (amd_uncore_nb)
                *per_cpu_ptr(amd_uncore_nb, cpu) = NULL;
        kfree(uncore_nb);
        return -ENOMEM;
}

static struct amd_uncore *
amd_uncore_find_online_sibling(struct amd_uncore *this,
                               struct amd_uncore * __percpu *uncores)
{
        unsigned int cpu;
        struct amd_uncore *that;

        for_each_online_cpu(cpu) {
                that = *per_cpu_ptr(uncores, cpu);

                if (!that)
                        continue;

                if (this == that)
                        continue;

                if (this->id == that->id) {
                        hlist_add_head(&this->node, &uncore_unused_list);
                        this = that;
                        break;
                }
        }

        this->refcnt++;
        return this;
}

static int amd_uncore_cpu_starting(unsigned int cpu)
{
        unsigned int eax, ebx, ecx, edx;
        struct amd_uncore *uncore;

        if (amd_uncore_nb) {
                uncore = *per_cpu_ptr(amd_uncore_nb, cpu);
                cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
                uncore->id = ecx & 0xff;

                uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_nb);
                *per_cpu_ptr(amd_uncore_nb, cpu) = uncore;
        }

        if (amd_uncore_llc) {
                uncore = *per_cpu_ptr(amd_uncore_llc, cpu);
                uncore->id = per_cpu(cpu_llc_id, cpu);

                uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_llc);
                *per_cpu_ptr(amd_uncore_llc, cpu) = uncore;
        }

        return 0;
}

static void uncore_clean_online(void)
{
        struct amd_uncore *uncore;
        struct hlist_node *n;

        hlist_for_each_entry_safe(uncore, n, &uncore_unused_list, node) {
                hlist_del(&uncore->node);
                kfree(uncore);
        }
}

static void uncore_online(unsigned int cpu,
                          struct amd_uncore * __percpu *uncores)
{
        struct amd_uncore *uncore = *per_cpu_ptr(uncores, cpu);

        uncore_clean_online();

        if (cpu == uncore->cpu)
                cpumask_set_cpu(cpu, uncore->active_mask);
}

static int amd_uncore_cpu_online(unsigned int cpu)
{
        if (amd_uncore_nb)
                uncore_online(cpu, amd_uncore_nb);

        if (amd_uncore_llc)
                uncore_online(cpu, amd_uncore_llc);

        return 0;
}

static void uncore_down_prepare(unsigned int cpu,
                                struct amd_uncore * __percpu *uncores)
{
        unsigned int i;
        struct amd_uncore *this = *per_cpu_ptr(uncores, cpu);

        if (this->cpu != cpu)
                return;

        /* this cpu is going down, migrate to a shared sibling if possible */
        for_each_online_cpu(i) {
                struct amd_uncore *that = *per_cpu_ptr(uncores, i);

                if (cpu == i)
                        continue;

                if (this == that) {
                        perf_pmu_migrate_context(this->pmu, cpu, i);
                        cpumask_clear_cpu(cpu, that->active_mask);
                        cpumask_set_cpu(i, that->active_mask);
                        that->cpu = i;
                        break;
                }
        }
}

static int amd_uncore_cpu_down_prepare(unsigned int cpu)
{
        if (amd_uncore_nb)
                uncore_down_prepare(cpu, amd_uncore_nb);

        if (amd_uncore_llc)
                uncore_down_prepare(cpu, amd_uncore_llc);

        return 0;
}

static void uncore_dead(unsigned int cpu, struct amd_uncore * __percpu *uncores)
{
        struct amd_uncore *uncore = *per_cpu_ptr(uncores, cpu);

        if (cpu == uncore->cpu)
                cpumask_clear_cpu(cpu, uncore->active_mask);

        if (!--uncore->refcnt)
                kfree(uncore);
        *per_cpu_ptr(uncores, cpu) = NULL;
}

static int amd_uncore_cpu_dead(unsigned int cpu)
{
        if (amd_uncore_nb)
                uncore_dead(cpu, amd_uncore_nb);

        if (amd_uncore_llc)
                uncore_dead(cpu, amd_uncore_llc);

        return 0;
}

static int __init amd_uncore_init(void)
{
        int ret = -ENODEV;

        if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
            boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
                return -ENODEV;

        if (!boot_cpu_has(X86_FEATURE_TOPOEXT))
                return -ENODEV;

        if (boot_cpu_data.x86 == 0x17 || boot_cpu_data.x86 == 0x18) {
                /*
                 * For F17h or F18h, the Northbridge counters are
                 * repurposed as Data Fabric counters. Also, L3
                 * counters are supported too. The PMUs are exported
                 * based on family as either L2 or L3 and NB or DF.
                 */
                num_counters_nb           = NUM_COUNTERS_NB;
                num_counters_llc          = NUM_COUNTERS_L3;
                amd_nb_pmu.name           = "amd_df";
                amd_llc_pmu.name          = "amd_l3";
                format_attr_event_df.show = &event_show_df;
                format_attr_event_l3.show = &event_show_l3;
                l3_mask                   = true;
        } else {
                num_counters_nb           = NUM_COUNTERS_NB;
                num_counters_llc          = NUM_COUNTERS_L2;
                amd_nb_pmu.name           = "amd_nb";
                amd_llc_pmu.name          = "amd_l2";
                format_attr_event_df      = format_attr_event;
                format_attr_event_l3      = format_attr_event;
                l3_mask                   = false;
        }

        amd_nb_pmu.attr_groups  = amd_uncore_attr_groups_df;
        amd_llc_pmu.attr_groups = amd_uncore_attr_groups_l3;

        if (boot_cpu_has(X86_FEATURE_PERFCTR_NB)) {
                amd_uncore_nb = alloc_percpu(struct amd_uncore *);
                if (!amd_uncore_nb) {
                        ret = -ENOMEM;
                        goto fail_nb;
                }
                ret = perf_pmu_register(&amd_nb_pmu, amd_nb_pmu.name, -1);
                if (ret)
                        goto fail_nb;

                pr_info("%s NB counters detected\n",
                        boot_cpu_data.x86_vendor == X86_VENDOR_HYGON ?
                                "HYGON" : "AMD");
                ret = 0;
        }

        if (boot_cpu_has(X86_FEATURE_PERFCTR_LLC)) {
                amd_uncore_llc = alloc_percpu(struct amd_uncore *);
                if (!amd_uncore_llc) {
                        ret = -ENOMEM;
                        goto fail_llc;
                }
                ret = perf_pmu_register(&amd_llc_pmu, amd_llc_pmu.name, -1);
                if (ret)
                        goto fail_llc;

                pr_info("%s LLC counters detected\n",
                        boot_cpu_data.x86_vendor == X86_VENDOR_HYGON ?
                                "HYGON" : "AMD");
                ret = 0;
        }

        /*
         * Install callbacks. Core will call them for each online cpu.
         */
        if (cpuhp_setup_state(CPUHP_PERF_X86_AMD_UNCORE_PREP,
                              "perf/x86/amd/uncore:prepare",
                              amd_uncore_cpu_up_prepare, amd_uncore_cpu_dead))
                goto fail_llc;

        if (cpuhp_setup_state(CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
                              "perf/x86/amd/uncore:starting",
                              amd_uncore_cpu_starting, NULL))
                goto fail_prep;
        if (cpuhp_setup_state(CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE,
                              "perf/x86/amd/uncore:online",
                              amd_uncore_cpu_online,
                              amd_uncore_cpu_down_prepare))
                goto fail_start;
        return 0;

fail_start:
        cpuhp_remove_state(CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING);
fail_prep:
        cpuhp_remove_state(CPUHP_PERF_X86_AMD_UNCORE_PREP);
fail_llc:
        if (boot_cpu_has(X86_FEATURE_PERFCTR_NB))
                perf_pmu_unregister(&amd_nb_pmu);
        if (amd_uncore_llc)
                free_percpu(amd_uncore_llc);
fail_nb:
        if (amd_uncore_nb)
                free_percpu(amd_uncore_nb);

        return ret;
}
device_initcall(amd_uncore_init);