/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008 Marcel Moolenaar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/bus.h>
#include <sys/cpuset.h>
#include <sys/domainset.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/smp.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>

#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/intr_machdep.h>
#include <machine/pcb.h>
#include <machine/platform.h>
#include <machine/md_var.h>
#include <machine/setjmp.h>
#include <machine/smp.h>

#include "pic_if.h"

volatile static int ap_awake;
volatile static u_int ap_letgo;
volatile static u_quad_t ap_timebase;
static struct mtx ap_boot_mtx;

void
machdep_ap_bootstrap(void)
{

        PCPU_SET(awake, 1);
        __asm __volatile("msync; isync");

        while (ap_letgo == 0)
                nop_prio_vlow();
        nop_prio_medium();

        /*
         * Set timebase as soon as possible to meet an implicit rendezvous
         * from cpu_mp_unleash(), which sets ap_letgo and then immediately
         * sets timebase.
         *
         * Note that this is instrinsically racy and is only relevant on
         * platforms that do not support better mechanisms.
         */
        platform_smp_timebase_sync(ap_timebase, 1);

        /* Give platform code a chance to do anything else necessary */
        platform_smp_ap_init();

        /* Initialize decrementer */
        decr_ap_init();

        /* Serialize console output and AP count increment */
        mtx_lock_spin(&ap_boot_mtx);
        ap_awake++;
        if (bootverbose)
                printf("SMP: AP CPU #%d launched\n", PCPU_GET(cpuid));
        else
                printf("%s%d%s", ap_awake == 2 ? "Launching APs: " : "",
                    PCPU_GET(cpuid), ap_awake == mp_ncpus ? "\n" : " ");
        mtx_unlock_spin(&ap_boot_mtx);

        while(smp_started == 0)
                ;

        /* Start per-CPU event timers. */
        cpu_initclocks_ap();

        /* Announce ourselves awake, and enter the scheduler */
        sched_ap_entry();
}

void
cpu_mp_setmaxid(void)
{
        struct cpuref cpuref;
        int error;

        mp_ncpus = 0;
        mp_maxid = 0;
        error = platform_smp_first_cpu(&cpuref);
        while (!error) {
                mp_ncpus++;
                mp_maxid = max(cpuref.cr_cpuid, mp_maxid);
                error = platform_smp_next_cpu(&cpuref);
        }
        /* Sanity. */
        if (mp_ncpus == 0)
                mp_ncpus = 1;
}

int
cpu_mp_probe(void)
{

        /*
         * We're not going to enable SMP if there's only 1 processor.
         */
        return (mp_ncpus > 1);
}

void
cpu_mp_start(void)
{
        struct cpuref bsp, cpu;
        struct pcpu *pc;
        int domain, error;

        error = platform_smp_get_bsp(&bsp);
        KASSERT(error == 0, ("Don't know BSP"));

        error = platform_smp_first_cpu(&cpu);
        while (!error) {
                if (cpu.cr_cpuid >= MAXCPU) {
                        printf("SMP: cpu%d: skipped -- ID out of range\n",
                            cpu.cr_cpuid);
                        goto next;
                }
                if (CPU_ISSET(cpu.cr_cpuid, &all_cpus)) {
                        printf("SMP: cpu%d: skipped - duplicate ID\n",
                            cpu.cr_cpuid);
                        goto next;
                }

                if (vm_ndomains > 1)
                        domain = cpu.cr_domain;
                else
                        domain = 0;

                if (cpu.cr_cpuid != bsp.cr_cpuid) {
                        void *dpcpu;

                        pc = &__pcpu[cpu.cr_cpuid];
                        dpcpu = kmem_malloc_domainset(DOMAINSET_PREF(domain),
                            DPCPU_SIZE, M_WAITOK | M_ZERO);
                        pcpu_init(pc, cpu.cr_cpuid, sizeof(*pc));
                        dpcpu_init(dpcpu, cpu.cr_cpuid);
                } else {
                        pc = pcpup;
                        pc->pc_cpuid = bsp.cr_cpuid;
                        pc->pc_bsp = 1;
                }
                pc->pc_domain = domain;
                pc->pc_hwref = cpu.cr_hwref;

                CPU_SET(pc->pc_cpuid, &cpuset_domain[pc->pc_domain]);
                KASSERT(pc->pc_domain < MAXMEMDOM, ("bad domain value %d\n",
                    pc->pc_domain));
                CPU_SET(pc->pc_cpuid, &all_cpus);
next:
                error = platform_smp_next_cpu(&cpu);
        }

#ifdef SMP
        platform_smp_probe_threads();
#endif
}

void
cpu_mp_announce(void)
{
        struct pcpu *pc;
        int i;

        if (!bootverbose)
                return;

        CPU_FOREACH(i) {
                pc = pcpu_find(i);
                if (pc == NULL)
                        continue;
                printf("cpu%d: dev=%x domain=%d ", i, (int)pc->pc_hwref, pc->pc_domain);
                if (pc->pc_bsp)
                        printf(" (BSP)");
                printf("\n");
        }
}

static void
cpu_mp_unleash(void *dummy)
{
        struct pcpu *pc;
        int cpus, timeout;
        int ret;

        if (mp_ncpus <= 1)
                return;

        mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);

        cpus = 0;
        smp_cpus = 0;
#ifdef BOOKE
        tlb1_ap_prep();
#endif
        STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
                cpus++;
                if (!pc->pc_bsp) {
                        if (bootverbose)
                                printf("Waking up CPU %d (dev=%x)\n",
                                    pc->pc_cpuid, (int)pc->pc_hwref);

                        pc->pc_flags = PCPU_GET(flags); /* Copy cached CPU flags */
                        ret = platform_smp_start_cpu(pc);
                        if (ret == 0) {
                                timeout = 2000; /* wait 2sec for the AP */
                                while (!pc->pc_awake && --timeout > 0)
                                        DELAY(1000);
                        }
                } else {
                        pc->pc_awake = 1;
                }
                if (pc->pc_awake) {
                        if (bootverbose)
                                printf("Adding CPU %d, hwref=%jx, awake=%x\n",
                                    pc->pc_cpuid, (uintmax_t)pc->pc_hwref,
                                    pc->pc_awake);
                        smp_cpus++;
                } else
                        CPU_SET(pc->pc_cpuid, &stopped_cpus);
        }

        ap_awake = 1;

        /* Provide our current DEC and TB values for APs */
        ap_timebase = mftb() + 10;
        __asm __volatile("msync; isync");

        /* Let APs continue */
        atomic_store_rel_int(&ap_letgo, 1);

        platform_smp_timebase_sync(ap_timebase, 0);

        while (ap_awake < smp_cpus)
                ;

        if (smp_cpus != cpus || cpus != mp_ncpus) {
                printf("SMP: %d CPUs found; %d CPUs usable; %d CPUs woken\n",
                    mp_ncpus, cpus, smp_cpus);
        }

        if (smp_cpus > 1)
                atomic_store_rel_int(&smp_started, 1);

        /* Let the APs get into the scheduler */
        DELAY(10000);

}

SYSINIT(start_aps, SI_SUB_SMP, SI_ORDER_FIRST, cpu_mp_unleash, NULL);

int
powerpc_ipi_handler(void *arg)
{
        u_int cpuid;
        uint32_t ipimask;

        CTR2(KTR_SMP, "%s: MSR 0x%08x", __func__, mfmsr());

        ipimask = atomic_readandclear_32(&(pcpup->pc_ipimask));
        if (ipimask == 0)
                return (FILTER_STRAY);
        if (ipimask & (1 << IPI_AST)) {
                CTR1(KTR_SMP, "%s: IPI_AST", __func__);
        }
        if (ipimask & (1 << IPI_PREEMPT)) {
                CTR1(KTR_SMP, "%s: IPI_PREEMPT", __func__);
                sched_preempt(curthread);
        }
        if (ipimask & (1 << IPI_RENDEZVOUS)) {
                CTR1(KTR_SMP, "%s: IPI_RENDEZVOUS", __func__);
                smp_rendezvous_action();
        }
        if (ipimask & (1 << IPI_STOP)) {

                /*
                 * IPI_STOP_HARD is mapped to IPI_STOP so it is not
                 * necessary to add such case.
                 */
                CTR1(KTR_SMP, "%s: IPI_STOP or IPI_STOP_HARD (stop)",
                                __func__);
                cpuid = PCPU_GET(cpuid);
                savectx(&stoppcbs[cpuid]);
                CPU_SET_ATOMIC(cpuid, &stopped_cpus);
                while (!CPU_ISSET(cpuid, &started_cpus))
                        cpu_spinwait();
                CPU_CLR_ATOMIC(cpuid, &stopped_cpus);
                CPU_CLR_ATOMIC(cpuid, &started_cpus);
                CTR1(KTR_SMP, "%s: IPI_STOP (restart)", __func__);
        }
        if (ipimask & (1 << IPI_HARDCLOCK)) {
                CTR1(KTR_SMP, "%s: IPI_HARDCLOCK", __func__);
                hardclockintr();
        }

        return (FILTER_HANDLED);
}

static void
ipi_send(struct pcpu *pc, int ipi)
{

        CTR4(KTR_SMP, "%s: pc=%p, targetcpu=%d, IPI=%d", __func__,
            pc, pc->pc_cpuid, ipi);

        atomic_set_32(&pc->pc_ipimask, (1 << ipi));
        powerpc_sync();
        PIC_IPI(root_pic, pc->pc_cpuid);

        CTR1(KTR_SMP, "%s: sent", __func__);
}

/* Send an IPI to a set of cpus. */
void
ipi_selected(cpuset_t cpus, int ipi)
{
        struct pcpu *pc;

        STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
                if (CPU_ISSET(pc->pc_cpuid, &cpus))
                        ipi_send(pc, ipi);
        }
}

/* Send an IPI to a specific CPU. */
void
ipi_cpu(int cpu, u_int ipi)
{

        ipi_send(cpuid_to_pcpu[cpu], ipi);
}

/* Send an IPI to all CPUs EXCEPT myself. */
void
ipi_all_but_self(int ipi)
{
        struct pcpu *pc;

        STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
                if (pc != pcpup)
                        ipi_send(pc, ipi);
        }
}