/*      $NetBSD: ipi.c,v 1.30 2019/12/01 15:34:46 ad Exp $      */

/*-
 * Copyright (c) 2000, 2008, 2009, 2019 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by RedBack Networks Inc.
 *
 * Author: Bill Sommerfeld
 *
 * 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ipi.c,v 1.30 2019/12/01 15:34:46 ad Exp $");

#include "opt_mtrr.h"

#include <sys/param.h>
#include <sys/device.h>
#include <sys/systm.h>
#include <sys/atomic.h>
#include <sys/intr.h>
#include <sys/ipi.h>
#include <sys/cpu.h>
#include <sys/xcall.h>

#ifdef MULTIPROCESSOR

#include <machine/cpufunc.h>
#include <machine/cpuvar.h>
#include <machine/i82093var.h>
#include <machine/i82489reg.h>
#include <machine/i82489var.h>
#include <machine/mtrr.h>
#include <machine/gdt.h>

#include "acpica.h"

#include <x86/fpu.h>

static void     x86_ipi_ast(struct cpu_info *);
static void     x86_ipi_halt(struct cpu_info *);
static void     x86_ipi_kpreempt(struct cpu_info *);
static void     x86_ipi_xcall(struct cpu_info *);
static void     x86_ipi_generic(struct cpu_info *);

#ifdef MTRR
static void     x86_ipi_reload_mtrr(struct cpu_info *);
#else
#define         x86_ipi_reload_mtrr     NULL
#endif

#if NACPICA > 0
void    acpi_cpu_sleep(struct cpu_info *);
#else
#define acpi_cpu_sleep  NULL
#endif

static void     x86_ipi_synch_fpu(struct cpu_info *);

void (* const ipifunc[X86_NIPI])(struct cpu_info *) =
{
        x86_ipi_halt,           /* X86_IPI_HALT */
        x86_ipi_ast,            /* X86_IPI_AST */
        x86_ipi_generic,        /* X86_IPI_GENERIC */
        x86_ipi_synch_fpu,      /* X86_IPI_SYNCH_FPU */
        x86_ipi_reload_mtrr,    /* X86_IPI_MTRR */
        NULL,                   /* X86_IPI_GDT */
        x86_ipi_xcall,          /* X86_IPI_XCALL */
        acpi_cpu_sleep,         /* X86_IPI_ACPI_CPU_SLEEP */
        x86_ipi_kpreempt        /* X86_IPI_KPREEMPT */
};

/*
 * x86 IPI interface.
 */

int
x86_send_ipi(struct cpu_info *ci, int ipimask)
{
        uint32_t o, n;
        int ret = 0;

        /* Don't send IPI to CPU which isn't (yet) running. */
        if (__predict_false((ci->ci_flags & CPUF_RUNNING) == 0))
                return ENOENT;

        /* Set in new IPI bit, and capture previous state. */
        for (o = 0;; o = n) {
                n = atomic_cas_32(&ci->ci_ipis, o, o | ipimask);
                if (__predict_true(o == n)) {
                        break;
                }
        }

        /* If no IPI already pending, send one. */
        if (o == 0) {
                ret = x86_ipi(LAPIC_IPI_VECTOR, ci->ci_cpuid, LAPIC_DLMODE_FIXED);
                if (ret != 0) {
                        printf("ipi of %x from %s to %s failed\n",
                            ipimask,
                            device_xname(curcpu()->ci_dev),
                            device_xname(ci->ci_dev));
                }
        }

        return ret;
}

void
x86_broadcast_ipi(int ipimask)
{
        struct cpu_info *ci, *self = curcpu();
        int count = 0;
        CPU_INFO_ITERATOR cii;

        for (CPU_INFO_FOREACH(cii, ci)) {
                if (ci == self)
                        continue;
                if ((ci->ci_flags & CPUF_RUNNING) == 0)
                        continue;
                atomic_or_32(&ci->ci_ipis, ipimask);
                count++;
        }
        if (!count)
                return;

        x86_ipi(LAPIC_IPI_VECTOR, LAPIC_DEST_ALLEXCL, LAPIC_DLMODE_FIXED);
}

void
x86_ipi_handler(void)
{
        struct cpu_info *ci = curcpu();
        uint32_t pending;
        int bit;

        pending = atomic_swap_32(&ci->ci_ipis, 0);

        KDASSERT((pending >> X86_NIPI) == 0);
        while ((bit = ffs(pending)) != 0) {
                bit--;
                pending &= ~(1 << bit);
                ci->ci_ipi_events[bit].ev_count++;
                (*ipifunc[bit])(ci);
        }
}

/*
 * Common x86 IPI handlers.
 */

static void
x86_ipi_halt(struct cpu_info *ci)
{

        x86_disable_intr();
        atomic_and_32(&ci->ci_flags, ~CPUF_RUNNING);

        for (;;) {
                x86_hlt();
        }
}

static void
x86_ipi_synch_fpu(struct cpu_info *ci)
{

        panic("%s: impossible", __func__);
}

#ifdef MTRR
static void
x86_ipi_reload_mtrr(struct cpu_info *ci)
{

        if (mtrr_funcs != NULL) {
                /*
                 * mtrr_reload_cpu() is a macro in mtrr.h which picks
                 * the appropriate function to use.
                 */
                mtrr_reload_cpu(ci);
        }
}
#endif

static void
x86_ipi_kpreempt(struct cpu_info *ci)
{

        softint_trigger(1 << SIR_PREEMPT);
}

static void
x86_ipi_ast(struct cpu_info *ci)
{

        aston(ci->ci_onproc);
}

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

static void
x86_ipi_xcall(struct cpu_info *ci)
{
        xc_ipi_handler();
}

static void
x86_ipi_generic(struct cpu_info *ci)
{
        ipi_cpu_handler();
}

void
xc_send_ipi(struct cpu_info *ci)
{

        KASSERT(kpreempt_disabled());
        KASSERT(curcpu() != ci);

        if (ci) {
                /* Unicast: remote CPU. */
                x86_send_ipi(ci, X86_IPI_XCALL);
        } else {
                /* Broadcast: all, but local CPU (caller will handle it). */
                x86_broadcast_ipi(X86_IPI_XCALL);
        }
}

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

        if (ci) {
                /* Unicast: remote CPU. */
                x86_send_ipi(ci, X86_IPI_GENERIC);
        } else {
                /* Broadcast: all, but local CPU (caller will handle it). */
                x86_broadcast_ipi(X86_IPI_GENERIC);
        }
}

#else

int
x86_send_ipi(struct cpu_info *ci, int ipimask)
{

        return 0;
}

void
x86_broadcast_ipi(int ipimask)
{

}

void
cpu_ipi(struct cpu_info *ci)
{
}

#endif