/*      $NetBSD: multicpu.c,v 1.37 2022/03/03 06:28:26 riastradh Exp $  */

/*
 * Copyright (c) 2000 Ludd, University of Lule}, Sweden. 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.
 */

/*
 * CPU-type independent code to spin up other VAX CPU's.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: multicpu.c,v 1.37 2022/03/03 06:28:26 riastradh Exp $");

#include "opt_multiprocessor.h"

#include <sys/param.h>
#include <sys/cpu.h>
#include <sys/device.h>
#include <sys/kmem.h>
#include <sys/proc.h>
#include <sys/xcall.h>
#include <sys/ipi.h>

#include <uvm/uvm_extern.h>

#include <vax/vax/gencons.h>

#include "ioconf.h"

const struct cpu_mp_dep *mp_dep_call;

struct cpuq {
        SIMPLEQ_ENTRY(cpuq) cq_q;
        struct cpu_info *cq_ci;
        device_t cq_dev;
};

SIMPLEQ_HEAD(, cpuq) cpuq = SIMPLEQ_HEAD_INITIALIZER(cpuq);

extern long avail_start, avail_end;
struct cpu_info_qh cpus = SIMPLEQ_HEAD_INITIALIZER(cpus);

void
cpu_boot_secondary_processors(void)
{
        struct cpuq *q;

        while ((q = SIMPLEQ_FIRST(&cpuq))) {
                SIMPLEQ_REMOVE_HEAD(&cpuq, cq_q);
                (*mp_dep_call->cpu_startslave)(q->cq_ci);
                kmem_free(q, sizeof(*q));
        }
}

/*
 * Allocate a cpu_info struct and fill it in then prepare for getting
 * started by cpu_boot_secondary_processors().
 */
void
cpu_slavesetup(device_t self, int slotid)
{
        struct cpu_info *ci;
        struct cpuq *cq;
        struct vm_page *pg;
        vaddr_t istackbase;

        KASSERT(device_private(self) == NULL);

        ci = kmem_zalloc(sizeof(*ci), KM_SLEEP);
        device_set_private(self, ci);
        ci->ci_dev = self;
        ci->ci_slotid = slotid;
        ci->ci_cpuid = device_unit(self);

        /* Allocate an interrupt stack */
        pg = uvm_pagealloc(NULL, 0, NULL, 0);
        if (pg == NULL)
                panic("cpu_slavesetup2");

        istackbase = VM_PAGE_TO_PHYS(pg) | KERNBASE;
        kvtopte(istackbase)->pg_v = 0; /* istack safety belt */

        /* Populate the PCB and the cpu_info struct */
        ci->ci_istack = istackbase + PAGE_SIZE;
        SIMPLEQ_INSERT_TAIL(&cpus, ci, ci_next);

        cq = kmem_zalloc(sizeof(*cq), KM_SLEEP);
        cq->cq_ci = ci;
        cq->cq_dev = ci->ci_dev;
        SIMPLEQ_INSERT_TAIL(&cpuq, cq, cq_q);

        mi_cpu_attach(ci);      /* let the MI parts know about the new cpu */
}

/*
 * Send an IPI of type type to the CPU with logical device number cpu.
 */
void
cpu_send_ipi(int cpu, int type)
{
        struct cpu_info *ci;
        int i;

        if (cpu >= 0) {
                ci = device_lookup_private(&cpu_cd, cpu);
                bbssi(type, &ci->ci_ipimsgs);
                (*mp_dep_call->cpu_send_ipi)(ci);
                return;
        }

        for (i = 0; i < cpu_cd.cd_ndevs; i++) {
                ci = device_lookup_private(&cpu_cd, i);
                if (ci == NULL)
                        continue;
                switch (cpu) {
                case IPI_DEST_MASTER:
                        if (ci->ci_flags & CI_MASTERCPU) {
                                bbssi(type, &ci->ci_ipimsgs);
                                (*mp_dep_call->cpu_send_ipi)(ci);
                        }
                        break;
                case IPI_DEST_ALL:
                        if (i == cpu_number())
                                continue;       /* No IPI to myself */
                        bbssi(type, &ci->ci_ipimsgs);
                        (*mp_dep_call->cpu_send_ipi)(ci);
                        break;
                }
        }
}

void
cpu_handle_ipi(void)
{
        struct cpu_info * const ci = curcpu();
        int bitno;
        int s;

        s = splhigh();

        while ((bitno = ffs(ci->ci_ipimsgs))) {
                bitno -= 1; /* ffs() starts from 1 */
                bbcci(bitno, &ci->ci_ipimsgs);
                switch (bitno) {
                case IPI_START_CNTX:
#ifdef DIAGNOSTIC
                        if (CPU_IS_PRIMARY(ci) == 0)
                                panic("cpu_handle_ipi");
#endif
                        gencnstarttx();
                        break;
                case IPI_SEND_CNCHAR:
#ifdef DIAGNOSTIC
                        if (CPU_IS_PRIMARY(ci) == 0)
                                panic("cpu_handle_ipi2");
#endif
                        (*mp_dep_call->cpu_cnintr)();
                        break;
                case IPI_RUNNING:
                        break;
                case IPI_TBIA:
                        mtpr(0, PR_TBIA);
                        break;
                case IPI_DDB:
                        Debugger();
                        break;
                case IPI_XCALL:
                        xc_ipi_handler();
                        break;
                case IPI_GENERIC:
                        ipi_cpu_handler();
                        break;
                default:
                        panic("cpu_handle_ipi: bad bit %x", bitno);
                }
        }
        splx(s);
}

/*
 * MD support for xcall(9) interface.
 */

void
xc_send_ipi(struct cpu_info *ci)
{
        KASSERT(kpreempt_disabled());
        KASSERT(curcpu() != ci);

        if (ci) {
                /* Unicast: remote CPU. */
                cpu_send_ipi(ci->ci_cpuid, IPI_XCALL);
        } else {
                /* Broadcast: all, but local CPU (caller will handle it). */
                cpu_send_ipi(IPI_DEST_ALL, IPI_XCALL);
        }
}

void
cpu_ipi(struct cpu_info *ci)
{
        KASSERT(kpreempt_disabled());
        KASSERT(curcpu() != ci);

        if (ci) {
                /* Unicast: remote CPU. */
                cpu_send_ipi(ci->ci_cpuid, IPI_GENERIC);
        } else {
                /* Broadcast: all, but local CPU (caller will handle it). */
                cpu_send_ipi(IPI_DEST_ALL, IPI_GENERIC);
        }
}