// SPDX-License-Identifier: GPL-2.0
/*
 * Arch specific cpu topology information
 *
 * Copyright (C) 2016, ARM Ltd.
 * Written by: Juri Lelli, ARM Ltd.
 */

#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sched/topology.h>
#include <linux/cpuset.h>
#include <linux/cpumask.h>
#include <linux/init.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/sched.h>
#include <linux/smp.h>

static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data);
static struct cpumask scale_freq_counters_mask;
static bool scale_freq_invariant;

static bool supports_scale_freq_counters(const struct cpumask *cpus)
{
        return cpumask_subset(cpus, &scale_freq_counters_mask);
}

bool topology_scale_freq_invariant(void)
{
        return cpufreq_supports_freq_invariance() ||
               supports_scale_freq_counters(cpu_online_mask);
}

static void update_scale_freq_invariant(bool status)
{
        if (scale_freq_invariant == status)
                return;

        /*
         * Task scheduler behavior depends on frequency invariance support,
         * either cpufreq or counter driven. If the support status changes as
         * a result of counter initialisation and use, retrigger the build of
         * scheduling domains to ensure the information is propagated properly.
         */
        if (topology_scale_freq_invariant() == status) {
                scale_freq_invariant = status;
                rebuild_sched_domains_energy();
        }
}

void topology_set_scale_freq_source(struct scale_freq_data *data,
                                    const struct cpumask *cpus)
{
        struct scale_freq_data *sfd;
        int cpu;

        /*
         * Avoid calling rebuild_sched_domains() unnecessarily if FIE is
         * supported by cpufreq.
         */
        if (cpumask_empty(&scale_freq_counters_mask))
                scale_freq_invariant = topology_scale_freq_invariant();

        rcu_read_lock();

        for_each_cpu(cpu, cpus) {
                sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));

                /* Use ARCH provided counters whenever possible */
                if (!sfd || sfd->source != SCALE_FREQ_SOURCE_ARCH) {
                        rcu_assign_pointer(per_cpu(sft_data, cpu), data);
                        cpumask_set_cpu(cpu, &scale_freq_counters_mask);
                }
        }

        rcu_read_unlock();

        update_scale_freq_invariant(true);
}
EXPORT_SYMBOL_GPL(topology_set_scale_freq_source);

void topology_clear_scale_freq_source(enum scale_freq_source source,
                                      const struct cpumask *cpus)
{
        struct scale_freq_data *sfd;
        int cpu;

        rcu_read_lock();

        for_each_cpu(cpu, cpus) {
                sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));

                if (sfd && sfd->source == source) {
                        rcu_assign_pointer(per_cpu(sft_data, cpu), NULL);
                        cpumask_clear_cpu(cpu, &scale_freq_counters_mask);
                }
        }

        rcu_read_unlock();

        /*
         * Make sure all references to previous sft_data are dropped to avoid
         * use-after-free races.
         */
        synchronize_rcu();

        update_scale_freq_invariant(false);
}
EXPORT_SYMBOL_GPL(topology_clear_scale_freq_source);

void topology_scale_freq_tick(void)
{
        struct scale_freq_data *sfd = rcu_dereference_sched(*this_cpu_ptr(&sft_data));

        if (sfd)
                sfd->set_freq_scale();
}

DEFINE_PER_CPU(unsigned long, arch_freq_scale) = SCHED_CAPACITY_SCALE;
EXPORT_PER_CPU_SYMBOL_GPL(arch_freq_scale);

void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
                             unsigned long max_freq)
{
        unsigned long scale;
        int i;

        if (WARN_ON_ONCE(!cur_freq || !max_freq))
                return;

        /*
         * If the use of counters for FIE is enabled, just return as we don't
         * want to update the scale factor with information from CPUFREQ.
         * Instead the scale factor will be updated from arch_scale_freq_tick.
         */
        if (supports_scale_freq_counters(cpus))
                return;

        scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;

        for_each_cpu(i, cpus)
                per_cpu(arch_freq_scale, i) = scale;
}

DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
EXPORT_PER_CPU_SYMBOL_GPL(cpu_scale);

void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
{
        per_cpu(cpu_scale, cpu) = capacity;
}

DEFINE_PER_CPU(unsigned long, thermal_pressure);

void topology_set_thermal_pressure(const struct cpumask *cpus,
                               unsigned long th_pressure)
{
        int cpu;

        for_each_cpu(cpu, cpus)
                WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
}
EXPORT_SYMBOL_GPL(topology_set_thermal_pressure);

static ssize_t cpu_capacity_show(struct device *dev,
                                 struct device_attribute *attr,
                                 char *buf)
{
        struct cpu *cpu = container_of(dev, struct cpu, dev);

        return sysfs_emit(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id));
}

static void update_topology_flags_workfn(struct work_struct *work);
static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);

static DEVICE_ATTR_RO(cpu_capacity);

static int register_cpu_capacity_sysctl(void)
{
        int i;
        struct device *cpu;

        for_each_possible_cpu(i) {
                cpu = get_cpu_device(i);
                if (!cpu) {
                        pr_err("%s: too early to get CPU%d device!\n",
                               __func__, i);
                        continue;
                }
                device_create_file(cpu, &dev_attr_cpu_capacity);
        }

        return 0;
}
subsys_initcall(register_cpu_capacity_sysctl);

static int update_topology;

int topology_update_cpu_topology(void)
{
        return update_topology;
}

/*
 * Updating the sched_domains can't be done directly from cpufreq callbacks
 * due to locking, so queue the work for later.
 */
static void update_topology_flags_workfn(struct work_struct *work)
{
        update_topology = 1;
        rebuild_sched_domains();
        pr_debug("sched_domain hierarchy rebuilt, flags updated\n");
        update_topology = 0;
}

static DEFINE_PER_CPU(u32, freq_factor) = 1;
static u32 *raw_capacity;

static int free_raw_capacity(void)
{
        kfree(raw_capacity);
        raw_capacity = NULL;

        return 0;
}

void topology_normalize_cpu_scale(void)
{
        u64 capacity;
        u64 capacity_scale;
        int cpu;

        if (!raw_capacity)
                return;

        capacity_scale = 1;
        for_each_possible_cpu(cpu) {
                capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
                capacity_scale = max(capacity, capacity_scale);
        }

        pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale);
        for_each_possible_cpu(cpu) {
                capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
                capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
                        capacity_scale);
                topology_set_cpu_scale(cpu, capacity);
                pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
                        cpu, topology_get_cpu_scale(cpu));
        }
}

bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
{
        struct clk *cpu_clk;
        static bool cap_parsing_failed;
        int ret;
        u32 cpu_capacity;

        if (cap_parsing_failed)
                return false;

        ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
                                   &cpu_capacity);
        if (!ret) {
                if (!raw_capacity) {
                        raw_capacity = kcalloc(num_possible_cpus(),
                                               sizeof(*raw_capacity),
                                               GFP_KERNEL);
                        if (!raw_capacity) {
                                cap_parsing_failed = true;
                                return false;
                        }
                }
                raw_capacity[cpu] = cpu_capacity;
                pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
                        cpu_node, raw_capacity[cpu]);

                /*
                 * Update freq_factor for calculating early boot cpu capacities.
                 * For non-clk CPU DVFS mechanism, there's no way to get the
                 * frequency value now, assuming they are running at the same
                 * frequency (by keeping the initial freq_factor value).
                 */
                cpu_clk = of_clk_get(cpu_node, 0);
                if (!PTR_ERR_OR_ZERO(cpu_clk)) {
                        per_cpu(freq_factor, cpu) =
                                clk_get_rate(cpu_clk) / 1000;
                        clk_put(cpu_clk);
                }
        } else {
                if (raw_capacity) {
                        pr_err("cpu_capacity: missing %pOF raw capacity\n",
                                cpu_node);
                        pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
                }
                cap_parsing_failed = true;
                free_raw_capacity();
        }

        return !ret;
}

#ifdef CONFIG_CPU_FREQ
static cpumask_var_t cpus_to_visit;
static void parsing_done_workfn(struct work_struct *work);
static DECLARE_WORK(parsing_done_work, parsing_done_workfn);

static int
init_cpu_capacity_callback(struct notifier_block *nb,
                           unsigned long val,
                           void *data)
{
        struct cpufreq_policy *policy = data;
        int cpu;

        if (!raw_capacity)
                return 0;

        if (val != CPUFREQ_CREATE_POLICY)
                return 0;

        pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
                 cpumask_pr_args(policy->related_cpus),
                 cpumask_pr_args(cpus_to_visit));

        cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);

        for_each_cpu(cpu, policy->related_cpus)
                per_cpu(freq_factor, cpu) = policy->cpuinfo.max_freq / 1000;

        if (cpumask_empty(cpus_to_visit)) {
                topology_normalize_cpu_scale();
                schedule_work(&update_topology_flags_work);
                free_raw_capacity();
                pr_debug("cpu_capacity: parsing done\n");
                schedule_work(&parsing_done_work);
        }

        return 0;
}

static struct notifier_block init_cpu_capacity_notifier = {
        .notifier_call = init_cpu_capacity_callback,
};

static int __init register_cpufreq_notifier(void)
{
        int ret;

        /*
         * on ACPI-based systems we need to use the default cpu capacity
         * until we have the necessary code to parse the cpu capacity, so
         * skip registering cpufreq notifier.
         */
        if (!acpi_disabled || !raw_capacity)
                return -EINVAL;

        if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL))
                return -ENOMEM;

        cpumask_copy(cpus_to_visit, cpu_possible_mask);

        ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
                                        CPUFREQ_POLICY_NOTIFIER);

        if (ret)
                free_cpumask_var(cpus_to_visit);

        return ret;
}
core_initcall(register_cpufreq_notifier);

static void parsing_done_workfn(struct work_struct *work)
{
        cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
                                         CPUFREQ_POLICY_NOTIFIER);
        free_cpumask_var(cpus_to_visit);
}

#else
core_initcall(free_raw_capacity);
#endif

#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
/*
 * This function returns the logic cpu number of the node.
 * There are basically three kinds of return values:
 * (1) logic cpu number which is > 0.
 * (2) -ENODEV when the device tree(DT) node is valid and found in the DT but
 * there is no possible logical CPU in the kernel to match. This happens
 * when CONFIG_NR_CPUS is configure to be smaller than the number of
 * CPU nodes in DT. We need to just ignore this case.
 * (3) -1 if the node does not exist in the device tree
 */
static int __init get_cpu_for_node(struct device_node *node)
{
        struct device_node *cpu_node;
        int cpu;

        cpu_node = of_parse_phandle(node, "cpu", 0);
        if (!cpu_node)
                return -1;

        cpu = of_cpu_node_to_id(cpu_node);
        if (cpu >= 0)
                topology_parse_cpu_capacity(cpu_node, cpu);
        else
                pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n",
                        cpu_node, cpumask_pr_args(cpu_possible_mask));

        of_node_put(cpu_node);
        return cpu;
}

static int __init parse_core(struct device_node *core, int package_id,
                             int core_id)
{
        char name[20];
        bool leaf = true;
        int i = 0;
        int cpu;
        struct device_node *t;

        do {
                snprintf(name, sizeof(name), "thread%d", i);
                t = of_get_child_by_name(core, name);
                if (t) {
                        leaf = false;
                        cpu = get_cpu_for_node(t);
                        if (cpu >= 0) {
                                cpu_topology[cpu].package_id = package_id;
                                cpu_topology[cpu].core_id = core_id;
                                cpu_topology[cpu].thread_id = i;
                        } else if (cpu != -ENODEV) {
                                pr_err("%pOF: Can't get CPU for thread\n", t);
                                of_node_put(t);
                                return -EINVAL;
                        }
                        of_node_put(t);
                }
                i++;
        } while (t);

        cpu = get_cpu_for_node(core);
        if (cpu >= 0) {
                if (!leaf) {
                        pr_err("%pOF: Core has both threads and CPU\n",
                               core);
                        return -EINVAL;
                }

                cpu_topology[cpu].package_id = package_id;
                cpu_topology[cpu].core_id = core_id;
        } else if (leaf && cpu != -ENODEV) {
                pr_err("%pOF: Can't get CPU for leaf core\n", core);
                return -EINVAL;
        }

        return 0;
}

static int __init parse_cluster(struct device_node *cluster, int depth)
{
        char name[20];
        bool leaf = true;
        bool has_cores = false;
        struct device_node *c;
        static int package_id __initdata;
        int core_id = 0;
        int i, ret;

        /*
         * First check for child clusters; we currently ignore any
         * information about the nesting of clusters and present the
         * scheduler with a flat list of them.
         */
        i = 0;
        do {
                snprintf(name, sizeof(name), "cluster%d", i);
                c = of_get_child_by_name(cluster, name);
                if (c) {
                        leaf = false;
                        ret = parse_cluster(c, depth + 1);
                        of_node_put(c);
                        if (ret != 0)
                                return ret;
                }
                i++;
        } while (c);

        /* Now check for cores */
        i = 0;
        do {
                snprintf(name, sizeof(name), "core%d", i);
                c = of_get_child_by_name(cluster, name);
                if (c) {
                        has_cores = true;

                        if (depth == 0) {
                                pr_err("%pOF: cpu-map children should be clusters\n",
                                       c);
                                of_node_put(c);
                                return -EINVAL;
                        }

                        if (leaf) {
                                ret = parse_core(c, package_id, core_id++);
                        } else {
                                pr_err("%pOF: Non-leaf cluster with core %s\n",
                                       cluster, name);
                                ret = -EINVAL;
                        }

                        of_node_put(c);
                        if (ret != 0)
                                return ret;
                }
                i++;
        } while (c);

        if (leaf && !has_cores)
                pr_warn("%pOF: empty cluster\n", cluster);

        if (leaf)
                package_id++;

        return 0;
}

static int __init parse_dt_topology(void)
{
        struct device_node *cn, *map;
        int ret = 0;
        int cpu;

        cn = of_find_node_by_path("/cpus");
        if (!cn) {
                pr_err("No CPU information found in DT\n");
                return 0;
        }

        /*
         * When topology is provided cpu-map is essentially a root
         * cluster with restricted subnodes.
         */
        map = of_get_child_by_name(cn, "cpu-map");
        if (!map)
                goto out;

        ret = parse_cluster(map, 0);
        if (ret != 0)
                goto out_map;

        topology_normalize_cpu_scale();

        /*
         * Check that all cores are in the topology; the SMP code will
         * only mark cores described in the DT as possible.
         */
        for_each_possible_cpu(cpu)
                if (cpu_topology[cpu].package_id == -1)
                        ret = -EINVAL;

out_map:
        of_node_put(map);
out:
        of_node_put(cn);
        return ret;
}
#endif

/*
 * cpu topology table
 */
struct cpu_topology cpu_topology[NR_CPUS];
EXPORT_SYMBOL_GPL(cpu_topology);

const struct cpumask *cpu_coregroup_mask(int cpu)
{
        const cpumask_t *core_mask = cpumask_of_node(cpu_to_node(cpu));

        /* Find the smaller of NUMA, core or LLC siblings */
        if (cpumask_subset(&cpu_topology[cpu].core_sibling, core_mask)) {
                /* not numa in package, lets use the package siblings */
                core_mask = &cpu_topology[cpu].core_sibling;
        }
        if (cpu_topology[cpu].llc_id != -1) {
                if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask))
                        core_mask = &cpu_topology[cpu].llc_sibling;
        }

        return core_mask;
}

void update_siblings_masks(unsigned int cpuid)
{
        struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
        int cpu;

        /* update core and thread sibling masks */
        for_each_online_cpu(cpu) {
                cpu_topo = &cpu_topology[cpu];

                if (cpuid_topo->llc_id == cpu_topo->llc_id) {
                        cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
                        cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
                }

                if (cpuid_topo->package_id != cpu_topo->package_id)
                        continue;

                cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
                cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);

                if (cpuid_topo->core_id != cpu_topo->core_id)
                        continue;

                cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
                cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
        }
}

static void clear_cpu_topology(int cpu)
{
        struct cpu_topology *cpu_topo = &cpu_topology[cpu];

        cpumask_clear(&cpu_topo->llc_sibling);
        cpumask_set_cpu(cpu, &cpu_topo->llc_sibling);

        cpumask_clear(&cpu_topo->core_sibling);
        cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
        cpumask_clear(&cpu_topo->thread_sibling);
        cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
}

void __init reset_cpu_topology(void)
{
        unsigned int cpu;

        for_each_possible_cpu(cpu) {
                struct cpu_topology *cpu_topo = &cpu_topology[cpu];

                cpu_topo->thread_id = -1;
                cpu_topo->core_id = -1;
                cpu_topo->package_id = -1;
                cpu_topo->llc_id = -1;

                clear_cpu_topology(cpu);
        }
}

void remove_cpu_topology(unsigned int cpu)
{
        int sibling;

        for_each_cpu(sibling, topology_core_cpumask(cpu))
                cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
        for_each_cpu(sibling, topology_sibling_cpumask(cpu))
                cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
        for_each_cpu(sibling, topology_llc_cpumask(cpu))
                cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling));

        clear_cpu_topology(cpu);
}

__weak int __init parse_acpi_topology(void)
{
        return 0;
}

#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
void __init init_cpu_topology(void)
{
        reset_cpu_topology();

        /*
         * Discard anything that was parsed if we hit an error so we
         * don't use partial information.
         */
        if (parse_acpi_topology())
                reset_cpu_topology();
        else if (of_have_populated_dt() && parse_dt_topology())
                reset_cpu_topology();
}
#endif