/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Copyright (C) 2000, 2001 Kanoj Sarcar
 * Copyright (C) 2000, 2001 Ralf Baechle
 * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
 * Copyright (C) 2000, 2001, 2003 Broadcom Corporation
 */
#include <linux/cache.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/export.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/sched/mm.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/ftrace.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_irq.h>

#include <linux/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/idle.h>
#include <asm/r4k-timer.h>
#include <asm/mips-cps.h>
#include <asm/mmu_context.h>
#include <asm/time.h>
#include <asm/setup.h>
#include <asm/maar.h>

int __cpu_number_map[CONFIG_MIPS_NR_CPU_NR_MAP];   /* Map physical to logical */
EXPORT_SYMBOL(__cpu_number_map);

int __cpu_logical_map[NR_CPUS];         /* Map logical to physical */
EXPORT_SYMBOL(__cpu_logical_map);

/* Number of TCs (or siblings in Intel speak) per CPU core */
int smp_num_siblings = 1;
EXPORT_SYMBOL(smp_num_siblings);

/* representing the TCs (or siblings in Intel speak) of each logical CPU */
cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(cpu_sibling_map);

/* representing the core map of multi-core chips of each logical CPU */
cpumask_t cpu_core_map[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(cpu_core_map);

static DECLARE_COMPLETION(cpu_starting);
static DECLARE_COMPLETION(cpu_running);

/*
 * A logcal cpu mask containing only one VPE per core to
 * reduce the number of IPIs on large MT systems.
 */
cpumask_t cpu_foreign_map[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(cpu_foreign_map);

/* representing cpus for which sibling maps can be computed */
static cpumask_t cpu_sibling_setup_map;

/* representing cpus for which core maps can be computed */
static cpumask_t cpu_core_setup_map;

cpumask_t cpu_coherent_mask;

#ifdef CONFIG_GENERIC_IRQ_IPI
static struct irq_desc *call_desc;
static struct irq_desc *sched_desc;
#endif

static inline void set_cpu_sibling_map(int cpu)
{
        int i;

        cpumask_set_cpu(cpu, &cpu_sibling_setup_map);

        if (smp_num_siblings > 1) {
                for_each_cpu(i, &cpu_sibling_setup_map) {
                        if (cpus_are_siblings(cpu, i)) {
                                cpumask_set_cpu(i, &cpu_sibling_map[cpu]);
                                cpumask_set_cpu(cpu, &cpu_sibling_map[i]);
                        }
                }
        } else
                cpumask_set_cpu(cpu, &cpu_sibling_map[cpu]);
}

static inline void set_cpu_core_map(int cpu)
{
        int i;

        cpumask_set_cpu(cpu, &cpu_core_setup_map);

        for_each_cpu(i, &cpu_core_setup_map) {
                if (cpu_data[cpu].package == cpu_data[i].package) {
                        cpumask_set_cpu(i, &cpu_core_map[cpu]);
                        cpumask_set_cpu(cpu, &cpu_core_map[i]);
                }
        }
}

/*
 * Calculate a new cpu_foreign_map mask whenever a
 * new cpu appears or disappears.
 */
void calculate_cpu_foreign_map(void)
{
        int i, k, core_present;
        cpumask_t temp_foreign_map;

        /* Re-calculate the mask */
        cpumask_clear(&temp_foreign_map);
        for_each_online_cpu(i) {
                core_present = 0;
                for_each_cpu(k, &temp_foreign_map)
                        if (cpus_are_siblings(i, k))
                                core_present = 1;
                if (!core_present)
                        cpumask_set_cpu(i, &temp_foreign_map);
        }

        for_each_online_cpu(i)
                cpumask_andnot(&cpu_foreign_map[i],
                               &temp_foreign_map, &cpu_sibling_map[i]);
}

const struct plat_smp_ops *mp_ops;
EXPORT_SYMBOL(mp_ops);

void register_smp_ops(const struct plat_smp_ops *ops)
{
        if (mp_ops)
                printk(KERN_WARNING "Overriding previously set SMP ops\n");

        mp_ops = ops;
}

#ifdef CONFIG_GENERIC_IRQ_IPI
void mips_smp_send_ipi_single(int cpu, unsigned int action)
{
        mips_smp_send_ipi_mask(cpumask_of(cpu), action);
}

void mips_smp_send_ipi_mask(const struct cpumask *mask, unsigned int action)
{
        unsigned long flags;
        unsigned int core;
        int cpu;

        local_irq_save(flags);

        switch (action) {
        case SMP_CALL_FUNCTION:
                __ipi_send_mask(call_desc, mask);
                break;

        case SMP_RESCHEDULE_YOURSELF:
                __ipi_send_mask(sched_desc, mask);
                break;

        default:
                BUG();
        }

        if (mips_cpc_present()) {
                for_each_cpu(cpu, mask) {
                        if (cpus_are_siblings(cpu, smp_processor_id()))
                                continue;

                        core = cpu_core(&cpu_data[cpu]);

                        while (!cpumask_test_cpu(cpu, &cpu_coherent_mask)) {
                                mips_cm_lock_other_cpu(cpu, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
                                mips_cpc_lock_other(core);
                                write_cpc_co_cmd(CPC_Cx_CMD_PWRUP);
                                mips_cpc_unlock_other();
                                mips_cm_unlock_other();
                        }
                }
        }

        local_irq_restore(flags);
}


static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id)
{
        scheduler_ipi();

        return IRQ_HANDLED;
}

static irqreturn_t ipi_call_interrupt(int irq, void *dev_id)
{
        generic_smp_call_function_interrupt();

        return IRQ_HANDLED;
}

static struct irqaction irq_resched = {
        .handler        = ipi_resched_interrupt,
        .flags          = IRQF_PERCPU,
        .name           = "IPI resched"
};

static struct irqaction irq_call = {
        .handler        = ipi_call_interrupt,
        .flags          = IRQF_PERCPU,
        .name           = "IPI call"
};

static void smp_ipi_init_one(unsigned int virq,
                                    struct irqaction *action)
{
        int ret;

        irq_set_handler(virq, handle_percpu_irq);
        ret = setup_irq(virq, action);
        BUG_ON(ret);
}

static unsigned int call_virq, sched_virq;

int mips_smp_ipi_allocate(const struct cpumask *mask)
{
        int virq;
        struct irq_domain *ipidomain;
        struct device_node *node;

        node = of_irq_find_parent(of_root);
        ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);

        /*
         * Some platforms have half DT setup. So if we found irq node but
         * didn't find an ipidomain, try to search for one that is not in the
         * DT.
         */
        if (node && !ipidomain)
                ipidomain = irq_find_matching_host(NULL, DOMAIN_BUS_IPI);

        /*
         * There are systems which use IPI IRQ domains, but only have one
         * registered when some runtime condition is met. For example a Malta
         * kernel may include support for GIC & CPU interrupt controller IPI
         * IRQ domains, but if run on a system with no GIC & no MT ASE then
         * neither will be supported or registered.
         *
         * We only have a problem if we're actually using multiple CPUs so fail
         * loudly if that is the case. Otherwise simply return, skipping IPI
         * setup, if we're running with only a single CPU.
         */
        if (!ipidomain) {
                BUG_ON(num_present_cpus() > 1);
                return 0;
        }

        virq = irq_reserve_ipi(ipidomain, mask);
        BUG_ON(!virq);
        if (!call_virq)
                call_virq = virq;

        virq = irq_reserve_ipi(ipidomain, mask);
        BUG_ON(!virq);
        if (!sched_virq)
                sched_virq = virq;

        if (irq_domain_is_ipi_per_cpu(ipidomain)) {
                int cpu;

                for_each_cpu(cpu, mask) {
                        smp_ipi_init_one(call_virq + cpu, &irq_call);
                        smp_ipi_init_one(sched_virq + cpu, &irq_resched);
                }
        } else {
                smp_ipi_init_one(call_virq, &irq_call);
                smp_ipi_init_one(sched_virq, &irq_resched);
        }

        return 0;
}

int mips_smp_ipi_free(const struct cpumask *mask)
{
        struct irq_domain *ipidomain;
        struct device_node *node;

        node = of_irq_find_parent(of_root);
        ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI);

        /*
         * Some platforms have half DT setup. So if we found irq node but
         * didn't find an ipidomain, try to search for one that is not in the
         * DT.
         */
        if (node && !ipidomain)
                ipidomain = irq_find_matching_host(NULL, DOMAIN_BUS_IPI);

        BUG_ON(!ipidomain);

        if (irq_domain_is_ipi_per_cpu(ipidomain)) {
                int cpu;

                for_each_cpu(cpu, mask) {
                        remove_irq(call_virq + cpu, &irq_call);
                        remove_irq(sched_virq + cpu, &irq_resched);
                }
        }
        irq_destroy_ipi(call_virq, mask);
        irq_destroy_ipi(sched_virq, mask);
        return 0;
}


static int __init mips_smp_ipi_init(void)
{
        if (num_possible_cpus() == 1)
                return 0;

        mips_smp_ipi_allocate(cpu_possible_mask);

        call_desc = irq_to_desc(call_virq);
        sched_desc = irq_to_desc(sched_virq);

        return 0;
}
early_initcall(mips_smp_ipi_init);
#endif

/*
 * First C code run on the secondary CPUs after being started up by
 * the master.
 */
asmlinkage void start_secondary(void)
{
        unsigned int cpu;

        cpu_probe();
        per_cpu_trap_init(false);
        mips_clockevent_init();
        mp_ops->init_secondary();
        cpu_report();
        maar_init();

        /*
         * XXX parity protection should be folded in here when it's converted
         * to an option instead of something based on .cputype
         */

        calibrate_delay();
        preempt_disable();
        cpu = smp_processor_id();
        cpu_data[cpu].udelay_val = loops_per_jiffy;

        cpumask_set_cpu(cpu, &cpu_coherent_mask);
        notify_cpu_starting(cpu);

        /* Notify boot CPU that we're starting & ready to sync counters */
        complete(&cpu_starting);

        synchronise_count_slave(cpu);

        /* The CPU is running and counters synchronised, now mark it online */
        set_cpu_online(cpu, true);

        set_cpu_sibling_map(cpu);
        set_cpu_core_map(cpu);

        calculate_cpu_foreign_map();

        /*
         * Notify boot CPU that we're up & online and it can safely return
         * from __cpu_up
         */
        complete(&cpu_running);

        /*
         * irq will be enabled in ->smp_finish(), enabling it too early
         * is dangerous.
         */
        WARN_ON_ONCE(!irqs_disabled());
        mp_ops->smp_finish();

        cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}

static void stop_this_cpu(void *dummy)
{
        /*
         * Remove this CPU:
         */

        set_cpu_online(smp_processor_id(), false);
        calculate_cpu_foreign_map();
        local_irq_disable();
        while (1);
}

void smp_send_stop(void)
{
        smp_call_function(stop_this_cpu, NULL, 0);
}

void __init smp_cpus_done(unsigned int max_cpus)
{
}

/* called from main before smp_init() */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
        init_new_context(current, &init_mm);
        current_thread_info()->cpu = 0;
        mp_ops->prepare_cpus(max_cpus);
        set_cpu_sibling_map(0);
        set_cpu_core_map(0);
        calculate_cpu_foreign_map();
#ifndef CONFIG_HOTPLUG_CPU
        init_cpu_present(cpu_possible_mask);
#endif
        cpumask_copy(&cpu_coherent_mask, cpu_possible_mask);
}

/* preload SMP state for boot cpu */
void smp_prepare_boot_cpu(void)
{
        set_cpu_possible(0, true);
        set_cpu_online(0, true);
}

int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
        int err;

        err = mp_ops->boot_secondary(cpu, tidle);
        if (err)
                return err;

        /* Wait for CPU to start and be ready to sync counters */
        if (!wait_for_completion_timeout(&cpu_starting,
                                         msecs_to_jiffies(1000))) {
                pr_crit("CPU%u: failed to start\n", cpu);
                return -EIO;
        }

        synchronise_count_master(cpu);

        /* Wait for CPU to finish startup & mark itself online before return */
        wait_for_completion(&cpu_running);
        return 0;
}

/* Not really SMP stuff ... */
int setup_profiling_timer(unsigned int multiplier)
{
        return 0;
}

static void flush_tlb_all_ipi(void *info)
{
        local_flush_tlb_all();
}

void flush_tlb_all(void)
{
        on_each_cpu(flush_tlb_all_ipi, NULL, 1);
}

static void flush_tlb_mm_ipi(void *mm)
{
        local_flush_tlb_mm((struct mm_struct *)mm);
}

/*
 * Special Variant of smp_call_function for use by TLB functions:
 *
 *  o No return value
 *  o collapses to normal function call on UP kernels
 *  o collapses to normal function call on systems with a single shared
 *    primary cache.
 */
static inline void smp_on_other_tlbs(void (*func) (void *info), void *info)
{
        smp_call_function(func, info, 1);
}

static inline void smp_on_each_tlb(void (*func) (void *info), void *info)
{
        preempt_disable();

        smp_on_other_tlbs(func, info);
        func(info);

        preempt_enable();
}

/*
 * The following tlb flush calls are invoked when old translations are
 * being torn down, or pte attributes are changing. For single threaded
 * address spaces, a new context is obtained on the current cpu, and tlb
 * context on other cpus are invalidated to force a new context allocation
 * at switch_mm time, should the mm ever be used on other cpus. For
 * multithreaded address spaces, intercpu interrupts have to be sent.
 * Another case where intercpu interrupts are required is when the target
 * mm might be active on another cpu (eg debuggers doing the flushes on
 * behalf of debugees, kswapd stealing pages from another process etc).
 * Kanoj 07/00.
 */

void flush_tlb_mm(struct mm_struct *mm)
{
        preempt_disable();

        if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
                smp_on_other_tlbs(flush_tlb_mm_ipi, mm);
        } else {
                unsigned int cpu;

                for_each_online_cpu(cpu) {
                        if (cpu != smp_processor_id() && cpu_context(cpu, mm))
                                cpu_context(cpu, mm) = 0;
                }
        }
        local_flush_tlb_mm(mm);

        preempt_enable();
}

struct flush_tlb_data {
        struct vm_area_struct *vma;
        unsigned long addr1;
        unsigned long addr2;
};

static void flush_tlb_range_ipi(void *info)
{
        struct flush_tlb_data *fd = info;

        local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
        struct mm_struct *mm = vma->vm_mm;

        preempt_disable();
        if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
                struct flush_tlb_data fd = {
                        .vma = vma,
                        .addr1 = start,
                        .addr2 = end,
                };

                smp_on_other_tlbs(flush_tlb_range_ipi, &fd);
        } else {
                unsigned int cpu;
                int exec = vma->vm_flags & VM_EXEC;

                for_each_online_cpu(cpu) {
                        /*
                         * flush_cache_range() will only fully flush icache if
                         * the VMA is executable, otherwise we must invalidate
                         * ASID without it appearing to has_valid_asid() as if
                         * mm has been completely unused by that CPU.
                         */
                        if (cpu != smp_processor_id() && cpu_context(cpu, mm))
                                cpu_context(cpu, mm) = !exec;
                }
        }
        local_flush_tlb_range(vma, start, end);
        preempt_enable();
}

static void flush_tlb_kernel_range_ipi(void *info)
{
        struct flush_tlb_data *fd = info;

        local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
}

void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
        struct flush_tlb_data fd = {
                .addr1 = start,
                .addr2 = end,
        };

        on_each_cpu(flush_tlb_kernel_range_ipi, &fd, 1);
}

static void flush_tlb_page_ipi(void *info)
{
        struct flush_tlb_data *fd = info;

        local_flush_tlb_page(fd->vma, fd->addr1);
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
        preempt_disable();
        if ((atomic_read(&vma->vm_mm->mm_users) != 1) || (current->mm != vma->vm_mm)) {
                struct flush_tlb_data fd = {
                        .vma = vma,
                        .addr1 = page,
                };

                smp_on_other_tlbs(flush_tlb_page_ipi, &fd);
        } else {
                unsigned int cpu;

                for_each_online_cpu(cpu) {
                        /*
                         * flush_cache_page() only does partial flushes, so
                         * invalidate ASID without it appearing to
                         * has_valid_asid() as if mm has been completely unused
                         * by that CPU.
                         */
                        if (cpu != smp_processor_id() && cpu_context(cpu, vma->vm_mm))
                                cpu_context(cpu, vma->vm_mm) = 1;
                }
        }
        local_flush_tlb_page(vma, page);
        preempt_enable();
}

static void flush_tlb_one_ipi(void *info)
{
        unsigned long vaddr = (unsigned long) info;

        local_flush_tlb_one(vaddr);
}

void flush_tlb_one(unsigned long vaddr)
{
        smp_on_each_tlb(flush_tlb_one_ipi, (void *) vaddr);
}

EXPORT_SYMBOL(flush_tlb_page);
EXPORT_SYMBOL(flush_tlb_one);

#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST

static DEFINE_PER_CPU(atomic_t, tick_broadcast_count);
static DEFINE_PER_CPU(call_single_data_t, tick_broadcast_csd);

void tick_broadcast(const struct cpumask *mask)
{
        atomic_t *count;
        call_single_data_t *csd;
        int cpu;

        for_each_cpu(cpu, mask) {
                count = &per_cpu(tick_broadcast_count, cpu);
                csd = &per_cpu(tick_broadcast_csd, cpu);

                if (atomic_inc_return(count) == 1)
                        smp_call_function_single_async(cpu, csd);
        }
}

static void tick_broadcast_callee(void *info)
{
        int cpu = smp_processor_id();
        tick_receive_broadcast();
        atomic_set(&per_cpu(tick_broadcast_count, cpu), 0);
}

static int __init tick_broadcast_init(void)
{
        call_single_data_t *csd;
        int cpu;

        for (cpu = 0; cpu < NR_CPUS; cpu++) {
                csd = &per_cpu(tick_broadcast_csd, cpu);
                csd->func = tick_broadcast_callee;
        }

        return 0;
}
early_initcall(tick_broadcast_init);

#endif /* CONFIG_GENERIC_CLOCKEVENTS_BROADCAST */